CA2374783A1 - Electrostatic image developing process with optimized setpoints - Google Patents
Electrostatic image developing process with optimized setpoints Download PDFInfo
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- CA2374783A1 CA2374783A1 CA002374783A CA2374783A CA2374783A1 CA 2374783 A1 CA2374783 A1 CA 2374783A1 CA 002374783 A CA002374783 A CA 002374783A CA 2374783 A CA2374783 A CA 2374783A CA 2374783 A1 CA2374783 A1 CA 2374783A1
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- velocity
- shell
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- electrostatic image
- toner
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G13/00—Electrographic processes using a charge pattern
- G03G13/06—Developing
- G03G13/08—Developing using a solid developer, e.g. powder developer
- G03G13/09—Developing using a solid developer, e.g. powder developer using magnetic brush
Abstract
The invention relates generally to processes for electrostatic image development and setpoints that provide uniform image development. In particular, an apparatus and process having a magnetic brush (14) formed from a developing mixture (16) of hard carriers and toner, a rotating magnetic core (20), and a rotating shell (18) enclosing the magnetic core is disclosed. The process implements one or more of the following optimum setpoints: a range of shell surface speeds that prevent toner plate-out, a skive spacing that minimizes sensitivity to variation, a magnetic core speed that minimizes sensitivity to variation, and an imaging member spacing that minimizes sensitivity to variation.
Description
ELECTROSTATIC IMAGE DEVELOPING
PROCESS WITH OPTIMIZED SETPOINTS
BACKGROUND
The invention relates generally to processes for electrostatic image development, and setpoints that provide uniform image development.
Processes for developing electrostatic images using dry toner are well known in the art.
A process that implements hard magnetic Garners and a rotating magnetic core is described in United States Patents 4,546,060 and 4,473,029. The rotating magnetic core promotes agitated flow of the tonerlcarrier mixture, which improves development relative to certain other development processes. In spite of such improvements, certain image artifacts still occur, some of which are the result of process setpoints. Therefore, a more robust process without image artifacts is generally desired.
SUMMARY
A process for developing electrostatic images comprising depositing a uniform toner density on an electrostatic image using a magnetic brush comprising hard magnetic carriers, a rotating shell, and a rotating plurality of magnets inside the rotating shell, without plating-out the rotating shell with toner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 presents a side cross-sectional view of an apparatus for developing electrostatic images, according to an aspect of the present invention.
FIG. 2 presents a side schematic view of a discharged area development configuration of the Figure 1 apparatus with a background area passing over a magnetic brush.
FIG. 3 presents a side schematic view of a discharged area development configuration of the Figure 1 apparatus with an area that is being toned passing over a magnetic brush.
FIG. 4 presents a plan view of an electrostatic imaging member having an electrostatic image.
FIG. 5 presents a plan view of Figure 4 electrostatic imaging member after development.
FIG. 6 presents a plot of toning density versus position for the developed image of Figure 5.
FIG. 7 presents a plan view of an electrostatic imaging member having an electrostatic image.
FIG. 8 presents a plan view of Figure 7 electrostatic imaging member after development.
-I-FIG. 9 presents a plot of toning density versus position for the developed image of Figure 8. ~ ' FIG. 10 presents a plot of core speed versus toning density.
FIG. 11 presents a plot of skive spacing versus toning density.
FIG. 12 presents a plot of electrostatic imaging member spacing relative to the magnetic brush shell versus toning density.
FIG. 13 presents a cross-sectional view of a toning station that implements the development apparatus of Figure 1.
FIG. 14 presents a toned image comprising a solid area followed by a half tone or grey area.
FIG. 15 presents development process of the Figure 14 image, according to an aspect of the invention.
DETAILED DESCRIPTION
Various aspects of the invention are presented in Figures 1-15, which are not drawn to scale, and wherein like components in the numerous views are numbered alike.
Referring now specifically to Figure 1, an apparatus and process are presented, according to an aspect of the invention. An apparatus 10 for developing electrostatic images is presented comprising an electrostatic imaging member 12 having an electrostatic image and a magnetic brush 14 comprising a rotating shell 18, a mixture 16 of hard magnetic carriers and toner (also referred to herein as "developer"), and a rotating plurality of magnets 20 inside the rotating shell 18. A
process for developing electrostatic images, according to an aspect of the invention, comprises depositing a uniform toner density on the electrostatic image using the magnetic brush 14 comprising hard magnetic carriers, a rotating shell 18, and a rotating plurality of magnets 20 inside the rotating shell 18, without plating-out the rotating shell 18 with toner. As used herein, "plate-out" refers to a condition wherein the external surface of the rotating shell 18 is coated with toner particles to the extent that the image is affected.
The magnetic brush 14 operates according to the principles described in United States Patents 4,473,029 and 4,546,060, the contents of which are fully incorporated by reference as if set forth herein. The two-component dry developer composition of United States Patent 4,546,060 comprises charged toner particles and oppositely charged, magnetic carrier particles, which (a) comprise a magnetic material exhibiting "hard" magnetic properties, as characterized by a coercivity of at least 300 gauss and (b) exhibit an induced magnetic moment of at least 20 EMLTIgm when in an applied field of 1000 gauss, is disclosed. As described in the '060 patent, the developer is employed in combination with a magnetic applicator comprising a rotatable -a-magnetic core and an outer, nonmagnetizable shell to develop electrostatic images. When hard magnetic carrier particle's are employed, exposure to a succession of magnetic fields emanating from the rotating core applicator causes the particles to flip or turn to move into magnetic alignment in each new field. Each flip, moreover, as a consequence of both the magnetic moment of the particles and the coercivity of the magnetic material, is accompanied by a rapid circumferential step by each particle in a direction opposite the movement of the rotating core.
The observed result is that the developers of the '060 flow smoothly and at a rapid rate around the shell while the core rotates in the opposite direction, thus rapidly delivering fresh toner to the photoconductor and facilitating high-volume copy and printer applications.
The electrostatic imaging member 12 of Figures 1-3 is configured as a sheet-like film.
However, it may be configured in other ways, such as a drum, depending upon the particular application. A film electrostatic imaging member 12 is relatively resilient, typically under tension, and a pair of backer bars 32 may be provided that hold the imaging member in a desired position relative to the shell 18, as shown in Figure 1.
According to a further aspect of the invention, the process comprises moving electrostatic imaging member 12 at a member velocity 24, and rotating the shell 18 with a shell surface velocity 26 adjacent the electrostatic imaging member 12 and co-directional with the member velocity 24. The shell 18 and magnetic poles 20 bring the mixture 16 of hard magnetic Garners and toner into contact with the electrostatic imaging member 12. The mixture 16 contacts that electrostatic imaging member 12 over a length indicated as L.
The electrostatic imaging member is electrically grounded 22 and defines a ground plane. The surface of the electrostatic imaging member facing the shell 18 is a photoconductor that can be treated at this point in the process as an electrical insulator, the shell opposite that is grounded is an electrical conductor. Biasing the shell relative to the ground 22 with a voltage V
creates an electric field that attracts toner particles to the electrostatic image with a uniform toner density, the electric field being a maximum where the shell 18 is adjacent to the electrostatic imaging member 12.
According to an aspect of the invention, toner plate-out is avoided by the electric field being a maximum where the shell 18 is adjacent to the electrostatic imaging member 12, and by the shell surface velocity 26 being greater than or equal to a minimum shell surface velocity below which toner plate-out occurs on the shell 18 adjacent the electrostatic imaging member 12.
This aspect of the invention is explained more fully with reference to Figures 2 and 3, wherein the apparatus 10 is presented in a configuration for Discharged Area Development (DAD). Cross-hatching and arrows indicating movement are removed for the sake of clarity.
Figure 2 represents development of a background area (no toner deposited), and Figure 3 represents development of a toned area (toner deposited). Referring specifically to Figure 2, the surface of the electrostatic imaging member 12 is charged using methods known in the electrostatic imaging arts to a negative static voltage, -750 VDC, for example, relative to ground. The shell is biased with a lesser negative voltage, -600 VDC, for example, relative to ground. The difference in electrical potential generates an electric field E
that is maximum where the imaging member 12 is adjacent the shell 18. The electric field E is presented at numerous locations proximate the surface of the shell 18 with relative strength indicated by the size of the arrows. The toner particles are negatively charged in a DAD
system, and are not drawn to the surface of the imaging member 12. However, the toner particles are drawn to the surface of the shell 18 where the electric field E is maximum (adjacent the electrostatic imaging member 12). Plate-out is avoided by moving the surface of the shell 18 through the contact length L faster than plate-out is able to occur (the minimum shell surface velocity below which toner plate-out occurs on the shell 18 adjacent the electrostatic imaging member 12). Plate-out on the remainder of the shell 18 is prevented by the agitated motion of the mixture 16 induced by the rotating magnet poles 20, and by avoiding placement of any biased structure adjacent the shell 18, other than the electrostatic imaging member 20, that would generate a plate-out causing electric field.
The existence of plate out may be determined experimentally in at least two ways. One, for example, is the appearance of image artifacts as described in United States Patent 4,473,029.
Alternatively, the magnetic brush 14 may be operated for an extended period of time and subsequently removed. The surface of the shell 18 may then be inspected for plate-out.
Referring now to Figure 3, the apparatus 10 of Figures 1 and 2 is shown with a discharged area of the electrostatic imaging member 12 passing over the magnetic brush 14.
The static voltage of -750 VDC on electrostatic imaging member 12 has been discharged to a lesser static voltage, -150 VDC, for example, by methods known in the art such as a laser or LED printing head, without limitation. Note that the sense of the electric field E is now reversed, and negative toner particles 46 are attracted to and adhere to the surface of the electrostatic imaging member. A residual positive charge is developed in the mixture 16, which is carried away by the flow of the mixture 16. Although described in relation to a DAD system, the principles described herein are equally applicable to a charged area development (CAD) system with positive toner particles.
Referring now to Figures 4-6, a DAD development process is presented wherein the shell surface velocity 26 (Figure 1) is too slow. The member velocity 24 is presented in Figures 4 and 5 for reference purposes. Refernng specifically to Figure 4, the electrostatic imaging member 12 has an electrostatic image comprising a charged area 28 and a discharged area 30.
Referring specifically to'Figure 5, the electrostatic imaging member 12 is presented after passing through the development zone L (Figure 1). The discharged area 30 of Figure 4 is now toned. Still referring to Figure 5, there is a zone 32 of greater toner density on the leading edge of the electrostatic image than on the balance 34 of the electrostatic image.
A plot of toner density versus position is presented in Figure 6.
Referring now to Figures 7-9, a DAD development process is presented wherein the shell surface velocity 26 (Figure 1) is too fast. The member velocity 24 is presented in Figures 7 and 8 for reference purposes. Referring specifically to Figure 7, the electrostatic imaging member 12 has the same electrostatic image as Figure 4 comprising the charged area 28 and the discharged area 30. Referring specifically to Figure 8, the electrostatic imaging member 12 is presented after passing through the development zone L (Figure 1). The discharged area 30 of Figure 7 is now toned. Still referring to Figure 7, there is a zone 36 of greater toner density on the trailing edge of the electrostatic image than on the balance 34 of the electrostatic image. A
plot of toner density versus position is presented in Figure 9.
Therefore, according to a further aspect of the invention, the shell suxface velocity 26 is greater than a shell surface velocity that creates noticeably greater toner density 32 on leading edges of the electrostatic image than on the balance 34 of the electrostatic image (Figures 4-6), and less than a shell surface velocity that creates noticeably greater toner density 36 on trailing edges of the electrostatic image than on the balance 34 of the electrostatic image (Figures 7-9).
Stated differently, there is a maximum shell surface velocity above (greater than) which toner density 36 on the trailing edges is noticeably greater than on the balance 34 of the electrostatic image, and there is a minimum shell surface velocity below (less than) which toner density 36 on the leading edges is noticeably greater than on the balance 34 of the electrostatic image, the shell surface velocity being greater than or equal to the minimum shell surface velocity and less than or equal to the maximum shell surface velocity. In practice, the toned image is transferred to a print media, such a sheet of paper or overhead transparency, without limitation, and the term "noticeably greater" means that the difference in toning density is discernable by the unaided human eye.
According to a fixrther aspect of the invention, the minimum shell velocity is 40% of the member velocity and the maximum shell velocity is 105% of the member velocity.
According to a preferred embodiment, the minimum shell velocity is 50% of the member velocity 24 and the maximum shell velocity is 105% of the member velocity 24. According to a particularly preferred embodiment, the minimum shell velocity is 50% of the member velocity 24 and the maximum shell velocity is 100% of the member velocity 24. According to a preferred embodiment, the'magnitude of the member velocity 24 is at least 11.4 inches per second and, more preferably, is at least than 15 inches per second. The development zone length L is preferably greater than 0.25 inches.
According to a further aspect of the invention, certain further setpoints are optimized to improve image uniformity. Referring now to Figure 10, a plot of core speed versus toning density is presented, showing a core speed setpoint 34, and an actual maximum 36. Here, toning density refers to the transmission density of the toned image on the photoconductor or on the receiver. The core speed is preferably set at the speed where the slope is approximately zero and also a maximum. Geaxing limitations may prevent the core speed setpoint 34 from corresponding to the actual maximum 36. According to a preferred embodiment, the setpoint 34 is close enough to the actual maximum such that gear chatter does not appear in the developed image.
Referring now to Figure 1 l, a plot of skive spacing versus toning density is presented, showing a skive space setpoint 38, and an actual maximum 40. Skive spacing S
is presented in Figure 1. Skive spacing is preferably set at the spacing S where the slope is approximately zero and also a maximum. Referring now to Figure 12, a plot of film spacing relative to the shell 18 is presented, showing a film spacing setpoint 42 and an actual minimum 44.
Filin spacing M is presented in Figure 1. Fihn spacing is preferably set at the spacing M where the slope is approximately zero and also a minimum. In Figures 11 and 12, the setpoints 38 and 42 are not set at the actual maximum 40 and minimum 44, respectively, in order to illustrate application of the invention in realistic situations wherein mechanical tolerances, for example, +/- 0.003 inches, are taken into account. The invention is useful if the optimum operating point falls within the tolerance range. The curves presented in Figures 10-12 are determined experimentally, and can vary depending upon the particular application.
Referring now to Figure 13, a development station is presented of the type that implements the development apparatus 10 according to the present invention.
The toning station has a nominally 2" diameter stainless steel toning shell containing a 14 pole magnetic core. Each alternating north and south pole has a field strength of approximately 1000 gauss.
The toner has diameter 11.5 microns. The hard magnetic carrier has diameter of approximately 30 microns and resistivity of 1011 ohm-cm. The starting point for tests at process speeds greater than 110 PPM was to increase toning station speeds proportionally to photoconductor speed, as shown below.
PROCESS WITH OPTIMIZED SETPOINTS
BACKGROUND
The invention relates generally to processes for electrostatic image development, and setpoints that provide uniform image development.
Processes for developing electrostatic images using dry toner are well known in the art.
A process that implements hard magnetic Garners and a rotating magnetic core is described in United States Patents 4,546,060 and 4,473,029. The rotating magnetic core promotes agitated flow of the tonerlcarrier mixture, which improves development relative to certain other development processes. In spite of such improvements, certain image artifacts still occur, some of which are the result of process setpoints. Therefore, a more robust process without image artifacts is generally desired.
SUMMARY
A process for developing electrostatic images comprising depositing a uniform toner density on an electrostatic image using a magnetic brush comprising hard magnetic carriers, a rotating shell, and a rotating plurality of magnets inside the rotating shell, without plating-out the rotating shell with toner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 presents a side cross-sectional view of an apparatus for developing electrostatic images, according to an aspect of the present invention.
FIG. 2 presents a side schematic view of a discharged area development configuration of the Figure 1 apparatus with a background area passing over a magnetic brush.
FIG. 3 presents a side schematic view of a discharged area development configuration of the Figure 1 apparatus with an area that is being toned passing over a magnetic brush.
FIG. 4 presents a plan view of an electrostatic imaging member having an electrostatic image.
FIG. 5 presents a plan view of Figure 4 electrostatic imaging member after development.
FIG. 6 presents a plot of toning density versus position for the developed image of Figure 5.
FIG. 7 presents a plan view of an electrostatic imaging member having an electrostatic image.
FIG. 8 presents a plan view of Figure 7 electrostatic imaging member after development.
-I-FIG. 9 presents a plot of toning density versus position for the developed image of Figure 8. ~ ' FIG. 10 presents a plot of core speed versus toning density.
FIG. 11 presents a plot of skive spacing versus toning density.
FIG. 12 presents a plot of electrostatic imaging member spacing relative to the magnetic brush shell versus toning density.
FIG. 13 presents a cross-sectional view of a toning station that implements the development apparatus of Figure 1.
FIG. 14 presents a toned image comprising a solid area followed by a half tone or grey area.
FIG. 15 presents development process of the Figure 14 image, according to an aspect of the invention.
DETAILED DESCRIPTION
Various aspects of the invention are presented in Figures 1-15, which are not drawn to scale, and wherein like components in the numerous views are numbered alike.
Referring now specifically to Figure 1, an apparatus and process are presented, according to an aspect of the invention. An apparatus 10 for developing electrostatic images is presented comprising an electrostatic imaging member 12 having an electrostatic image and a magnetic brush 14 comprising a rotating shell 18, a mixture 16 of hard magnetic carriers and toner (also referred to herein as "developer"), and a rotating plurality of magnets 20 inside the rotating shell 18. A
process for developing electrostatic images, according to an aspect of the invention, comprises depositing a uniform toner density on the electrostatic image using the magnetic brush 14 comprising hard magnetic carriers, a rotating shell 18, and a rotating plurality of magnets 20 inside the rotating shell 18, without plating-out the rotating shell 18 with toner. As used herein, "plate-out" refers to a condition wherein the external surface of the rotating shell 18 is coated with toner particles to the extent that the image is affected.
The magnetic brush 14 operates according to the principles described in United States Patents 4,473,029 and 4,546,060, the contents of which are fully incorporated by reference as if set forth herein. The two-component dry developer composition of United States Patent 4,546,060 comprises charged toner particles and oppositely charged, magnetic carrier particles, which (a) comprise a magnetic material exhibiting "hard" magnetic properties, as characterized by a coercivity of at least 300 gauss and (b) exhibit an induced magnetic moment of at least 20 EMLTIgm when in an applied field of 1000 gauss, is disclosed. As described in the '060 patent, the developer is employed in combination with a magnetic applicator comprising a rotatable -a-magnetic core and an outer, nonmagnetizable shell to develop electrostatic images. When hard magnetic carrier particle's are employed, exposure to a succession of magnetic fields emanating from the rotating core applicator causes the particles to flip or turn to move into magnetic alignment in each new field. Each flip, moreover, as a consequence of both the magnetic moment of the particles and the coercivity of the magnetic material, is accompanied by a rapid circumferential step by each particle in a direction opposite the movement of the rotating core.
The observed result is that the developers of the '060 flow smoothly and at a rapid rate around the shell while the core rotates in the opposite direction, thus rapidly delivering fresh toner to the photoconductor and facilitating high-volume copy and printer applications.
The electrostatic imaging member 12 of Figures 1-3 is configured as a sheet-like film.
However, it may be configured in other ways, such as a drum, depending upon the particular application. A film electrostatic imaging member 12 is relatively resilient, typically under tension, and a pair of backer bars 32 may be provided that hold the imaging member in a desired position relative to the shell 18, as shown in Figure 1.
According to a further aspect of the invention, the process comprises moving electrostatic imaging member 12 at a member velocity 24, and rotating the shell 18 with a shell surface velocity 26 adjacent the electrostatic imaging member 12 and co-directional with the member velocity 24. The shell 18 and magnetic poles 20 bring the mixture 16 of hard magnetic Garners and toner into contact with the electrostatic imaging member 12. The mixture 16 contacts that electrostatic imaging member 12 over a length indicated as L.
The electrostatic imaging member is electrically grounded 22 and defines a ground plane. The surface of the electrostatic imaging member facing the shell 18 is a photoconductor that can be treated at this point in the process as an electrical insulator, the shell opposite that is grounded is an electrical conductor. Biasing the shell relative to the ground 22 with a voltage V
creates an electric field that attracts toner particles to the electrostatic image with a uniform toner density, the electric field being a maximum where the shell 18 is adjacent to the electrostatic imaging member 12.
According to an aspect of the invention, toner plate-out is avoided by the electric field being a maximum where the shell 18 is adjacent to the electrostatic imaging member 12, and by the shell surface velocity 26 being greater than or equal to a minimum shell surface velocity below which toner plate-out occurs on the shell 18 adjacent the electrostatic imaging member 12.
This aspect of the invention is explained more fully with reference to Figures 2 and 3, wherein the apparatus 10 is presented in a configuration for Discharged Area Development (DAD). Cross-hatching and arrows indicating movement are removed for the sake of clarity.
Figure 2 represents development of a background area (no toner deposited), and Figure 3 represents development of a toned area (toner deposited). Referring specifically to Figure 2, the surface of the electrostatic imaging member 12 is charged using methods known in the electrostatic imaging arts to a negative static voltage, -750 VDC, for example, relative to ground. The shell is biased with a lesser negative voltage, -600 VDC, for example, relative to ground. The difference in electrical potential generates an electric field E
that is maximum where the imaging member 12 is adjacent the shell 18. The electric field E is presented at numerous locations proximate the surface of the shell 18 with relative strength indicated by the size of the arrows. The toner particles are negatively charged in a DAD
system, and are not drawn to the surface of the imaging member 12. However, the toner particles are drawn to the surface of the shell 18 where the electric field E is maximum (adjacent the electrostatic imaging member 12). Plate-out is avoided by moving the surface of the shell 18 through the contact length L faster than plate-out is able to occur (the minimum shell surface velocity below which toner plate-out occurs on the shell 18 adjacent the electrostatic imaging member 12). Plate-out on the remainder of the shell 18 is prevented by the agitated motion of the mixture 16 induced by the rotating magnet poles 20, and by avoiding placement of any biased structure adjacent the shell 18, other than the electrostatic imaging member 20, that would generate a plate-out causing electric field.
The existence of plate out may be determined experimentally in at least two ways. One, for example, is the appearance of image artifacts as described in United States Patent 4,473,029.
Alternatively, the magnetic brush 14 may be operated for an extended period of time and subsequently removed. The surface of the shell 18 may then be inspected for plate-out.
Referring now to Figure 3, the apparatus 10 of Figures 1 and 2 is shown with a discharged area of the electrostatic imaging member 12 passing over the magnetic brush 14.
The static voltage of -750 VDC on electrostatic imaging member 12 has been discharged to a lesser static voltage, -150 VDC, for example, by methods known in the art such as a laser or LED printing head, without limitation. Note that the sense of the electric field E is now reversed, and negative toner particles 46 are attracted to and adhere to the surface of the electrostatic imaging member. A residual positive charge is developed in the mixture 16, which is carried away by the flow of the mixture 16. Although described in relation to a DAD system, the principles described herein are equally applicable to a charged area development (CAD) system with positive toner particles.
Referring now to Figures 4-6, a DAD development process is presented wherein the shell surface velocity 26 (Figure 1) is too slow. The member velocity 24 is presented in Figures 4 and 5 for reference purposes. Refernng specifically to Figure 4, the electrostatic imaging member 12 has an electrostatic image comprising a charged area 28 and a discharged area 30.
Referring specifically to'Figure 5, the electrostatic imaging member 12 is presented after passing through the development zone L (Figure 1). The discharged area 30 of Figure 4 is now toned. Still referring to Figure 5, there is a zone 32 of greater toner density on the leading edge of the electrostatic image than on the balance 34 of the electrostatic image.
A plot of toner density versus position is presented in Figure 6.
Referring now to Figures 7-9, a DAD development process is presented wherein the shell surface velocity 26 (Figure 1) is too fast. The member velocity 24 is presented in Figures 7 and 8 for reference purposes. Referring specifically to Figure 7, the electrostatic imaging member 12 has the same electrostatic image as Figure 4 comprising the charged area 28 and the discharged area 30. Referring specifically to Figure 8, the electrostatic imaging member 12 is presented after passing through the development zone L (Figure 1). The discharged area 30 of Figure 7 is now toned. Still referring to Figure 7, there is a zone 36 of greater toner density on the trailing edge of the electrostatic image than on the balance 34 of the electrostatic image. A
plot of toner density versus position is presented in Figure 9.
Therefore, according to a further aspect of the invention, the shell suxface velocity 26 is greater than a shell surface velocity that creates noticeably greater toner density 32 on leading edges of the electrostatic image than on the balance 34 of the electrostatic image (Figures 4-6), and less than a shell surface velocity that creates noticeably greater toner density 36 on trailing edges of the electrostatic image than on the balance 34 of the electrostatic image (Figures 7-9).
Stated differently, there is a maximum shell surface velocity above (greater than) which toner density 36 on the trailing edges is noticeably greater than on the balance 34 of the electrostatic image, and there is a minimum shell surface velocity below (less than) which toner density 36 on the leading edges is noticeably greater than on the balance 34 of the electrostatic image, the shell surface velocity being greater than or equal to the minimum shell surface velocity and less than or equal to the maximum shell surface velocity. In practice, the toned image is transferred to a print media, such a sheet of paper or overhead transparency, without limitation, and the term "noticeably greater" means that the difference in toning density is discernable by the unaided human eye.
According to a fixrther aspect of the invention, the minimum shell velocity is 40% of the member velocity and the maximum shell velocity is 105% of the member velocity.
According to a preferred embodiment, the minimum shell velocity is 50% of the member velocity 24 and the maximum shell velocity is 105% of the member velocity 24. According to a particularly preferred embodiment, the minimum shell velocity is 50% of the member velocity 24 and the maximum shell velocity is 100% of the member velocity 24. According to a preferred embodiment, the'magnitude of the member velocity 24 is at least 11.4 inches per second and, more preferably, is at least than 15 inches per second. The development zone length L is preferably greater than 0.25 inches.
According to a further aspect of the invention, certain further setpoints are optimized to improve image uniformity. Referring now to Figure 10, a plot of core speed versus toning density is presented, showing a core speed setpoint 34, and an actual maximum 36. Here, toning density refers to the transmission density of the toned image on the photoconductor or on the receiver. The core speed is preferably set at the speed where the slope is approximately zero and also a maximum. Geaxing limitations may prevent the core speed setpoint 34 from corresponding to the actual maximum 36. According to a preferred embodiment, the setpoint 34 is close enough to the actual maximum such that gear chatter does not appear in the developed image.
Referring now to Figure 1 l, a plot of skive spacing versus toning density is presented, showing a skive space setpoint 38, and an actual maximum 40. Skive spacing S
is presented in Figure 1. Skive spacing is preferably set at the spacing S where the slope is approximately zero and also a maximum. Referring now to Figure 12, a plot of film spacing relative to the shell 18 is presented, showing a film spacing setpoint 42 and an actual minimum 44.
Filin spacing M is presented in Figure 1. Fihn spacing is preferably set at the spacing M where the slope is approximately zero and also a minimum. In Figures 11 and 12, the setpoints 38 and 42 are not set at the actual maximum 40 and minimum 44, respectively, in order to illustrate application of the invention in realistic situations wherein mechanical tolerances, for example, +/- 0.003 inches, are taken into account. The invention is useful if the optimum operating point falls within the tolerance range. The curves presented in Figures 10-12 are determined experimentally, and can vary depending upon the particular application.
Referring now to Figure 13, a development station is presented of the type that implements the development apparatus 10 according to the present invention.
The toning station has a nominally 2" diameter stainless steel toning shell containing a 14 pole magnetic core. Each alternating north and south pole has a field strength of approximately 1000 gauss.
The toner has diameter 11.5 microns. The hard magnetic carrier has diameter of approximately 30 microns and resistivity of 1011 ohm-cm. The starting point for tests at process speeds greater than 110 PPM was to increase toning station speeds proportionally to photoconductor speed, as shown below.
Image artifacts can be produced during toning at high process speeds by the countercharge in'the developer, for example the positive charges noted in Figure 3. The countercharge can cause solid areas to have dark leading edges and light trail edges. For solid areas embedded in halftone fields, a halo artifact can occur at the trail edge of the solid area, as presented in Figure 14. Referring to Figure 14, the photoconductor 12 comprises a developed image 48 having an elongate solid area 50 followed by a half tone area 52.
Note that an undeveloped halo area 54 immediately follows the solid area 50. The halo area 54 is generated due to build up of positive charge in the developer 16 while toning the solid area 50.
For a given shell speed and photoconductor speed, the extent of the halo can be used to estimate the value of shell speed needed to prevent this problem. Referring now to Figure 15, development of image 48 of Figure 14 is presented. The trailing edge of the solid area 50 is at the center of the toning zone of width L. The toning shell adjacent the trail edge has been exposed to the solid area for time t = (L/2) / VS, (1) where VS is toning shell velocity. The time t in seconds also represents a number of toning time constants and countercharge removal time constants. Until this location on the toning shell leaves the toning zone, it will be adjacent the photoconductor for a distance x on the photoconductor, with x given by x = t~m - Vs)a (2) where Vm is the photoconductor velocity. From (1) and (2), x = (L/2) ~m - VS) / Vs. (3) Where x = 5/16" for the extent of the halo at 110 PPM, with the halo measured from the trail edge of the solid to the point in the subsequent gray area where image density has recovered to half its normal density. The toning nip has effective width L of approximately 0.352". According to this example, VS greater than 75% of Vm reduces the halo to less than 1/16" in length. According to an aspect of the invention, the halo is minimized, but not entirely eliminated, since the countercharge is removed by flow of the developer 16.
Increasing shell speed Vs increases the flow rate of developer, increases the rate of removal of countercharge from the develop~nerit zone L, and minimizes halo.
Although the invention has been described and illustrated with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. Those skilled in the art will recognize that variations and modifications can be made without departing from the true scope and spirit of the invention as defined by the claims that follow. For example, the invention can be used with electrophotographic or electrographic images. The invention can be used with imaging elements or photoconductors in either web or drum formats. Optimized setpoints for some embodiments may be attained using reflection density instead of transmission density, and the exact values of optimum setpoints may depend on the geometry of particular embodiments or particular characteristics of development in those embodiments. It is therefore intended to include within the invention all such variations and modifications as fall within the scope of the appended claims and equivalents thereof.
_g_
Note that an undeveloped halo area 54 immediately follows the solid area 50. The halo area 54 is generated due to build up of positive charge in the developer 16 while toning the solid area 50.
For a given shell speed and photoconductor speed, the extent of the halo can be used to estimate the value of shell speed needed to prevent this problem. Referring now to Figure 15, development of image 48 of Figure 14 is presented. The trailing edge of the solid area 50 is at the center of the toning zone of width L. The toning shell adjacent the trail edge has been exposed to the solid area for time t = (L/2) / VS, (1) where VS is toning shell velocity. The time t in seconds also represents a number of toning time constants and countercharge removal time constants. Until this location on the toning shell leaves the toning zone, it will be adjacent the photoconductor for a distance x on the photoconductor, with x given by x = t~m - Vs)a (2) where Vm is the photoconductor velocity. From (1) and (2), x = (L/2) ~m - VS) / Vs. (3) Where x = 5/16" for the extent of the halo at 110 PPM, with the halo measured from the trail edge of the solid to the point in the subsequent gray area where image density has recovered to half its normal density. The toning nip has effective width L of approximately 0.352". According to this example, VS greater than 75% of Vm reduces the halo to less than 1/16" in length. According to an aspect of the invention, the halo is minimized, but not entirely eliminated, since the countercharge is removed by flow of the developer 16.
Increasing shell speed Vs increases the flow rate of developer, increases the rate of removal of countercharge from the develop~nerit zone L, and minimizes halo.
Although the invention has been described and illustrated with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. Those skilled in the art will recognize that variations and modifications can be made without departing from the true scope and spirit of the invention as defined by the claims that follow. For example, the invention can be used with electrophotographic or electrographic images. The invention can be used with imaging elements or photoconductors in either web or drum formats. Optimized setpoints for some embodiments may be attained using reflection density instead of transmission density, and the exact values of optimum setpoints may depend on the geometry of particular embodiments or particular characteristics of development in those embodiments. It is therefore intended to include within the invention all such variations and modifications as fall within the scope of the appended claims and equivalents thereof.
_g_
Claims (42)
1. A process for developing electrostatic images comprising depositing a uniform toner density on an electrostatic image using a magnetic brush comprising hard magnetic carriers, a rotating shell, and a rotating plurality of magnets inside said rotating shell, without plating-out said rotating shell with toner.
2. The process of claim 1, further comprising moving said electrostatic image over said magnetic brush at a speed at least 11.4 inches per second.
3. The process of claim 1, further comprising moving said electrostatic image over said magnetic brush at a speed greater than 15 inches per second.
4. The process of claim 1, further comprising a development zone length where said magnetic brush contacts said electrostatic image that is greater than 0.25 inches.
5. The process of claim 1, wherein said electrostatic image is on an electrostatic imaging member having a member velocity, and said shell has a surface velocity co-directional with said member velocity that is 40% to 105% of said member velocity.
6. The process of claim 1, wherein said electrostatic image is on an electrostatic imaging member having a member velocity, and said shell has a surface velocity co-directional with said member velocity that is 50% to 105% of said member velocity.
7. The process of claim 1, wherein said electrostatic image is on an electrostatic imaging member having a member velocity, and said shell has a surface velocity co-directional with said member velocity that is 50% to 100% of said member velocity.
8. A process for developing electrostatic images, comprising:
moving an electrostatic imaging member having an electrostatic image at a member velocity;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity; and rotating a plurality of magnetic poles inside said shell, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member thereby depositing toner on said electrostatic image with a uniform toner density, wherein said shell surface velocity is greater than or equal to a minimum shell surface velocity below which toner plate-out occurs on said shell adjacent said electrostatic image member thereby preventing toner plate-out on said shell.
moving an electrostatic imaging member having an electrostatic image at a member velocity;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity; and rotating a plurality of magnetic poles inside said shell, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member thereby depositing toner on said electrostatic image with a uniform toner density, wherein said shell surface velocity is greater than or equal to a minimum shell surface velocity below which toner plate-out occurs on said shell adjacent said electrostatic image member thereby preventing toner plate-out on said shell.
9. The process of claim 8, wherein said member velocity is at least 11.4 inches per second.
10. The process of claim 8, wherein said member velocity is greater than 15 inches per second.
11. The process of claim 8, further comprising a development zone length where said mixture of toner and hard magnetic carriers contact said electrostatic imaging member that is greater than 0.25 inches.
12. The process of claim 8, wherein said shell surface velocity is in the range of 40% to 105%
of said member velocity.
of said member velocity.
13. The process of claim 8, wherein said shell surface velocity is 50% to 105%
of said member velocity.
of said member velocity.
14. The process of claim 8, wherein said shell surface velocity is 50% to 100%
of said member velocity.
of said member velocity.
15. A process for developing electrostatic images, comprising:
moving an electrostatic imaging member having an electrostatic image at a member velocity;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity; and rotating a plurality of magnetic poles inside said shell, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member thereby depositing toner on said electrostatic image;
said shell surface velocity being greater than a shell surface velocity that creates noticeably greater toner density on leading edges of said electrostatic image than on the balance of said electrostatic image, and less than a shell surface velocity that creates noticeably greater toner density on trailing edges of said electrostatic image than on the balance of said electrostatic image.
moving an electrostatic imaging member having an electrostatic image at a member velocity;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity; and rotating a plurality of magnetic poles inside said shell, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member thereby depositing toner on said electrostatic image;
said shell surface velocity being greater than a shell surface velocity that creates noticeably greater toner density on leading edges of said electrostatic image than on the balance of said electrostatic image, and less than a shell surface velocity that creates noticeably greater toner density on trailing edges of said electrostatic image than on the balance of said electrostatic image.
16. The process of claim 15, wherein said member velocity is at least 11.4 inches per second.
17. The process of claim 15, wherein said member velocity is greater than 15 inches per second.
18. The process of claim 15, further comprising a development zone length where said mixture of toner and hard magnetic carriers contact said electrostatic imaging member that is greater than 0.25 inches.
19. The process of claim 15, wherein said shell surface velocity that creates noticeably greater toner density on leading edges of said electrostatic image than on the balance of said electrostatic image is less than 40% of said member velocity, and shell surface velocity that creates noticeably greater toner density on trailing edges of said electrostatic image than on the balance of said electrostatic image is greater than 105% of said member velocity.
20. The process of claim 15, wherein said shell surface velocity that creates noticeably greater toner density on leading edges of said electrostatic image than on the balance of said electrostatic image is less than 50% of said member velocity, and shell surface velocity that creates noticeably greater toner density on trailing edges of said electrostatic image than on the balance of said electrostatic image is greater than 105% of said member velocity.
21. The process of claim 15, wherein said shell surface velocity that creates noticeably greater toner density on leading edges of said electrostatic image than on the balance of said electrostatic image is less than 50% of said member velocity, and shell surface velocity that creates noticeably greater toner density on trailing edges of said electrostatic image than on the balance of said electrostatic image is greater than 100% of said member velocity.
22. A process for developing electrostatic images, comprising:
moving an electrostatic imaging member having an electrostatic image at a member velocity, said electrostatic image having leading edges and trailing edges;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity; and rotating a plurality of magnetic poles inside a shell and rotating said shell with a shell surface velocity co-directional with said member velocity, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member thereby depositing toner on said electrostatic image with a toner density wherein (a) there is a minimum shell surface velocity below which toner density on said leading edges is noticeably greater than on the balance of said electrostatic image, and (b) there is a maximum shell surface velocity above which toner density on said trailing edges is noticeably greater than on the balance of said electrostatic image, said shell surface velocity being greater than or equal to said minimum shell surface velocity and less than or equal to said maximum shell surface velocity.
moving an electrostatic imaging member having an electrostatic image at a member velocity, said electrostatic image having leading edges and trailing edges;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity; and rotating a plurality of magnetic poles inside a shell and rotating said shell with a shell surface velocity co-directional with said member velocity, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member thereby depositing toner on said electrostatic image with a toner density wherein (a) there is a minimum shell surface velocity below which toner density on said leading edges is noticeably greater than on the balance of said electrostatic image, and (b) there is a maximum shell surface velocity above which toner density on said trailing edges is noticeably greater than on the balance of said electrostatic image, said shell surface velocity being greater than or equal to said minimum shell surface velocity and less than or equal to said maximum shell surface velocity.
23. The process of claim 22, wherein said member velocity is at least 11.4 inches per second.
24. The process of claim 22, wherein said member velocity is greater than 15 inches per second.
25. The process of claim 22, further comprising a development zone length where said mixture of toner and hard magnetic carriers contact said electrostatic imaging member that is greater than 0.25 inches.
26. The process of claim 22, wherein said minimum shell velocity is 40% of said member velocity and said maximum shell velocity is 105% of said member velocity.
27. The process of claim 22, wherein said minimum shell velocity is 50% of said member velocity and said maximum shell velocity is 105% of said member velocity.
28. The process of claim 22, wherein said minimum shell velocity is 50% of said member velocity and said maximum shell velocity is 100% of said member velocity.
29. A process for developing electrostatic images, comprising:
moving an electrostatic imaging member having an electrostatic image at a member velocity, said electrostatic imaging member being electrically grounded and defining a ground plane;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity;
rotating a plurality of magnetic poles inside said shell, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member; and, biasing said shell relative to said ground with a voltage thereby creating an electric field that attracts toner particles to said electrostatic image with a uniform toner density, said electric field being a maximum where said shell is adjacent to said electrostatic member;
wherein said shell surface velocity is greater than or equal to a minimum shell surface velocity below which toner plate-out occurs on said shell adjacent said electrostatic imaging member.
moving an electrostatic imaging member having an electrostatic image at a member velocity, said electrostatic imaging member being electrically grounded and defining a ground plane;
rotating a shell with a shell surface velocity adjacent said electrostatic imaging member and co-directional with said member velocity;
rotating a plurality of magnetic poles inside said shell, said shell and said magnetic poles bringing a mixture of toner and hard magnetic carriers into contact with said electrostatic imaging member; and, biasing said shell relative to said ground with a voltage thereby creating an electric field that attracts toner particles to said electrostatic image with a uniform toner density, said electric field being a maximum where said shell is adjacent to said electrostatic member;
wherein said shell surface velocity is greater than or equal to a minimum shell surface velocity below which toner plate-out occurs on said shell adjacent said electrostatic imaging member.
30. The process of claim 29, further comprising a development zone length where said mixture of toner and hard magnetic carriers contact said electrostatic imaging member that is greater than 0.25 inches.
31. The process of claim 29, wherein said member velocity is at least 11.4 inches per second.
32. The process of claim 29, wherein said member velocity is greater than 15 inches per second.
33. The process of claim 29, wherein said shell surface velocity is greater than or equal to 40%
of said member velocity and said shell surface velocity is less than or equal to 105% of said member velocity.
of said member velocity and said shell surface velocity is less than or equal to 105% of said member velocity.
34. The process of claim 29, wherein said shell surface velocity is greater than or equal to 50%
of said member velocity and said shell surface velocity is less than or equal to 105% of said member velocity.
of said member velocity and said shell surface velocity is less than or equal to 105% of said member velocity.
35. The process of claim 29, wherein said shell surface velocity is greater than or equal to 50%
of said member velocity and said shell surface velocity is less than or equal to 100% of said member velocity.
of said member velocity and said shell surface velocity is less than or equal to 100% of said member velocity.
36. A process for developing electrostatic images comprising depositing a uniform toner density on an electrostatic image using a magnetic brush comprising hard magnetic carriers, a rotating shell, and a rotating plurality of magnets inside said rotating shell, without plating-out said rotating shell with toner, and minimizing halo in a grey or half-tone area following an area of greater toner density by increasing shell surface velocity.
37. The process of claim 36, further comprising moving said electrostatic image over said magnetic brush at a speed at least 11.4 inches per second.
38. The process of claim 36, further comprising moving said electrostatic image over said magnetic brush at a speed greater than 15 inches per second.
39. The process of claim 36, further comprising a development zone length where said magnetic brush contacts said electrostatic image that is greater than 0.25 inches.
40. The process of claim 36, wherein said electrostatic image is on an electrostatic imaging member having a member velocity, and said shell has a surface velocity co-directional with said member velocity that is 40% to 105% of said member velocity.
41. The process of claim 36, wherein said electrostatic image is on an electrostatic imaging member having a member velocity, and said shell has a surface velocity co-directional with said member velocity that is 50% to 105% of said member velocity.
42. The process of claim 36, wherein said electrostatic image is on an electrostatic imaging member having a member velocity, and said shell has a surface velocity co-directional with said member velocity that is 50% to 100% of said member velocity.
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Families Citing this family (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6728503B2 (en) | 2001-02-28 | 2004-04-27 | Heidelberger Druckmaschinen Ag | Electrophotographic image developing process with optimized average developer bulk velocity |
US6946230B2 (en) | 2001-11-13 | 2005-09-20 | Heidelberger Druckmaschinen Ag | Electrostatic image developing processes and compositions |
CN100487807C (en) | 2002-10-04 | 2009-05-13 | Lg电子有限公司 | Recording medium having a data structure for managing reproduction of graphic data and recording and reproducing methods and apparatuses |
US7110706B1 (en) | 2003-04-11 | 2006-09-19 | Eastman Kodak Company | Toner replenisher and method for an electrographic imaging machine |
US7120379B2 (en) * | 2003-09-26 | 2006-10-10 | Eastman Kodak Company | Electrographic development method and apparatus |
US20050142468A1 (en) | 2003-12-24 | 2005-06-30 | Eastman Kodak Company | Printing system, process, and product with a variable pantograph |
WO2005088406A2 (en) * | 2004-03-09 | 2005-09-22 | Eastman Kodak Company | Powder coating using an electromagnetic brush |
US20060150902A1 (en) * | 2004-03-09 | 2006-07-13 | Eastman Kodak Company | Powder coating apparatus and method of powder coating using an electromagnetic brush |
GB0407312D0 (en) * | 2004-03-31 | 2004-05-05 | Phoqus Pharmaceuticals Ltd | Method and apparatus for the application of powder material to substrates |
DE102005004125B4 (en) * | 2005-01-28 | 2007-01-18 | OCé PRINTING SYSTEMS GMBH | Apparatus and method for coloring a charge image with toner material in a printer or copier |
US20060250656A1 (en) * | 2005-05-05 | 2006-11-09 | Eastman Kodak Company | Printing system, process, and product with a variable watermark |
US7426361B2 (en) * | 2005-09-01 | 2008-09-16 | Eastman Kodak Company | Developer mixing apparatus having four ribbon blenders |
US7885584B2 (en) * | 2007-06-29 | 2011-02-08 | Eastman Kodak Company | Self-cleaning electrophotographic toning roller system |
US8219009B2 (en) * | 2009-03-31 | 2012-07-10 | Eastman Kodak Company | Developer station and method for an electrographic printer with magnetically enabled developer removal |
US8204411B2 (en) * | 2009-07-31 | 2012-06-19 | Eastman Kodak Company | Electrographic image developing apparatus and method for developing including compensation for slippage |
US8224209B2 (en) * | 2009-08-18 | 2012-07-17 | Eastman Kodak Company | High-frequency banding reduction for electrophotographic printer |
US8311463B2 (en) * | 2009-08-18 | 2012-11-13 | Eastman Kodak Company | Method and system to reduce high-frequency banding for electrophotographic development stations |
US8452204B2 (en) * | 2010-06-03 | 2013-05-28 | Eastman Kodak Company | Process control with longitudinal member toner removal |
Family Cites Families (91)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4546060A (en) | 1982-11-08 | 1985-10-08 | Eastman Kodak Company | Two-component, dry electrographic developer compositions containing hard magnetic carrier particles and method for using the same |
US4602863A (en) | 1983-07-01 | 1986-07-29 | Eastman Kodak Company | Electrographic development method, apparatus and system |
US4473029A (en) * | 1983-07-01 | 1984-09-25 | Eastman Kodak Company | Electrographic magnetic brush development method, apparatus and system |
US4531832A (en) | 1983-08-01 | 1985-07-30 | Eastman Kodak Company | Electrographic apparatus, method and system employing image development adjustment |
US4496643A (en) | 1984-03-23 | 1985-01-29 | Eastman Kodak Company | Two-component dry electrostatic developer composition containing onium charge control agent |
US4887132A (en) | 1984-04-06 | 1989-12-12 | Eastman Kodak Company | Electrographic development apparatus having a ribbon blender |
US4637973A (en) * | 1984-11-15 | 1987-01-20 | Konishiroku Photo Industry Co., Ltd. | Image forming process for electrophotography |
US4634286A (en) | 1985-09-06 | 1987-01-06 | Eastman Kodak Company | Electrographic development apparatus having a continuous coil ribbon blender |
US4714046A (en) | 1985-11-20 | 1987-12-22 | Eastman Kodak Company | Electrographic magnetic brush development apparatus and system |
US4671207A (en) | 1985-12-11 | 1987-06-09 | Eastman Kodak Company | Magnetic brush development apparatus |
EP0227006B1 (en) * | 1985-12-17 | 1991-03-13 | Konica Corporation | A method of developing electrostatic latent images |
US4764445A (en) | 1987-06-15 | 1988-08-16 | Eastman Kodak Company | Electrographic magnetic carrier particles |
US4825244A (en) | 1987-11-23 | 1989-04-25 | Eastman Kodak Company | Development station with improved mixing and feeding apparatus |
US4922302A (en) | 1988-07-07 | 1990-05-01 | Eastman Kodak Company | Device for developing electrostatic images on a film belt |
US5001028A (en) | 1988-08-15 | 1991-03-19 | Eastman Kodak Company | Electrophotographic method using hard magnetic carrier particles |
US4949127A (en) * | 1988-11-28 | 1990-08-14 | Mita Industrial Co., Ltd. | Magnetic brush development process |
EP0371734B1 (en) * | 1988-11-28 | 1994-01-12 | Mita Industrial Co., Ltd. | Magnetic brush development process |
JPH03170978A (en) * | 1989-11-29 | 1991-07-24 | Mita Ind Co Ltd | Developing device |
US5019796A (en) | 1989-12-22 | 1991-05-28 | Eastman Kodak Company | Bar magnet for construction of a magnetic roller core |
US4967236A (en) | 1989-12-27 | 1990-10-30 | Eastman Kodak Company | Charge retention xeroprinting |
US5484680A (en) * | 1990-02-28 | 1996-01-16 | Hitachi Metals, Ltd. | Magnetic brush developing method |
US5061586A (en) | 1990-04-05 | 1991-10-29 | Eastman Kodak Company | Glass composite magnetic carrier particles |
US5043760A (en) | 1990-04-09 | 1991-08-27 | Eastman Kodak Company | Carrier particle loosening device |
US5040003A (en) | 1990-06-04 | 1991-08-13 | Eastman Kodak Company | Method and apparatus for recording color with plural printheads |
US5106714A (en) | 1990-08-01 | 1992-04-21 | Eastman Kodak Company | Interdispersed two-phase ferrite composite and electrographic magnetic carrier particles therefrom |
US5063399A (en) | 1990-08-06 | 1991-11-05 | Eastman Kodak Company | Electrophotographic apparatus having reduced drum drive flutter |
JP2979599B2 (en) * | 1990-08-10 | 1999-11-15 | ミノルタ株式会社 | Electrophotographic development |
US5095340A (en) | 1990-09-06 | 1992-03-10 | Eastman Kodak Company | Method of controlling the operation of a magnetic brush toning station |
US5104761A (en) | 1990-09-14 | 1992-04-14 | Eastman Kodak Company | Interdispersed three-phase ferrite composite and electrographic magnetic carrier particles therefrom |
US5066981A (en) | 1990-10-15 | 1991-11-19 | Eastman Kodak Company | Mechanism for responsively spacing a development roller |
US5047807A (en) | 1990-10-15 | 1991-09-10 | Eastman Kodak Company | Development apparatus having a plate scavenging device |
US5138388A (en) | 1990-12-24 | 1992-08-11 | Eastman Kodak Company | Method and apparatus for removing unexposed marking particles with magnetic carrier particles |
WO1992009936A1 (en) | 1990-11-30 | 1992-06-11 | Eastman Kodak Company | Migration imaging system |
US5227265A (en) | 1990-11-30 | 1993-07-13 | Eastman Kodak Company | Migration imaging system |
US5182608A (en) | 1990-12-03 | 1993-01-26 | Eastman Kodak Company | Method and apparatus for applying toner to an electrostatic image |
US5111245A (en) | 1990-12-03 | 1992-05-05 | Eastman Kodak Company | Apparatus for positioning a development unit with respect to an image member |
US5247331A (en) | 1991-11-19 | 1993-09-21 | Eastman Kodak Company | Color image forming apparatus with translatable development apparatus having an integral wheel mount |
US5237127A (en) | 1990-12-24 | 1993-08-17 | Eastman Kodak Company | Development apparatus having means for translating development units in producing multicolor images |
US5132732A (en) | 1991-01-22 | 1992-07-21 | Eastman Kodak Company | Dual axis displacement lifting mechanism for a development apparatus |
US5084739A (en) | 1991-01-22 | 1992-01-28 | Eastman Kodak Company | Self-loading cleaning blade and holder therefor |
US5146278A (en) | 1991-03-15 | 1992-09-08 | Eastman Kodak Company | Apparatus for applying toner to an electrostatic image |
US5196887A (en) | 1991-06-07 | 1993-03-23 | Eastman Kodak Company | Image forming apparatus having a magnetic brush toning station |
US5148220A (en) | 1991-06-07 | 1992-09-15 | Eastman Kodak Company | Toning station drive for image-forming apparatus |
US5162854A (en) | 1991-06-07 | 1992-11-10 | Eastman Kodak Company | Image forming apparatus having at least two toning stations |
US5300988A (en) | 1991-06-07 | 1994-04-05 | Eastman Kodak Company | Toning station for selectively applying toner to an electrostatic image |
JPH056099A (en) | 1991-06-28 | 1993-01-14 | Mita Ind Co Ltd | Developing method |
US5184194A (en) | 1991-10-28 | 1993-02-02 | Eastman Kodak Company | Carrier particle scavenging device |
US5190842A (en) | 1991-12-19 | 1993-03-02 | Eastman Kodak Company | Two phase ferroelectric-ferromagnetic composite carrier |
US5190841A (en) | 1991-12-19 | 1993-03-02 | Eastman Kodak Company | Two-phase ferroelectric-ferromagnetic composite and carrier therefrom |
US5245388A (en) | 1992-04-27 | 1993-09-14 | Eastman Kodak Company | Image forming apparatus including indexible toning units |
US5241327A (en) | 1992-06-01 | 1993-08-31 | Eastman Kodak Company | Method and apparatus for removing untacked toner from images |
US5280302A (en) | 1992-06-05 | 1994-01-18 | Eastman Kodak Company | Recording apparatus with magnetic brush removal of non-tacked toner |
US5298358A (en) | 1992-06-29 | 1994-03-29 | Eastman Kodak Company | Method and apparatus for reproducing image information |
US5296898A (en) | 1992-08-05 | 1994-03-22 | Eastman Kodak Company | Method for producing images |
US5332645A (en) | 1992-09-28 | 1994-07-26 | Eastman Kodak Company | Low dusting carriers |
US5347345A (en) | 1992-10-19 | 1994-09-13 | Eastman Kodak Company | Method and apparatus of creating two-color images in a single pass |
US5306592A (en) | 1992-10-29 | 1994-04-26 | Eastman Kodak Company | Method of preparing electrographic magnetic carrier particles |
US5268249A (en) | 1992-10-29 | 1993-12-07 | Eastman Kodak Company | Magnetic carrier particles |
US5339140A (en) | 1992-11-04 | 1994-08-16 | Eastman Kodak Company | Method and apparatus for control of toner charge |
US5293201A (en) | 1992-11-09 | 1994-03-08 | Eastman Kodak Company | Image forming apparatus in which toner is recycled between toner applying and cleaning stations |
US5296905A (en) | 1992-11-12 | 1994-03-22 | Eastman Kodak Company | Cleaning device using magnetic particulate cleaning material |
US5291259A (en) | 1992-11-12 | 1994-03-01 | Eastman Kodak Company | Image forming apparatus having toner cleaning device |
US5400124A (en) | 1992-11-16 | 1995-03-21 | Eastman Kodak Company | Development station having a roughened toning shell |
US5313993A (en) | 1992-12-03 | 1994-05-24 | Eastman Kodak Company | Toner container and receiving apparatus therefor |
US5296894A (en) | 1992-12-03 | 1994-03-22 | Eastman Kodak Company | Image forming apparatus and an image member cartridge containing a photoconductive drum |
US5255053A (en) | 1992-12-03 | 1993-10-19 | Eastman Kodak Company | Image forming apparatus having a transfer drum, an image member cartridge and exposure means |
US5268719A (en) | 1992-12-03 | 1993-12-07 | Eastman Kodak Company | Image forming apparatus having a positioning mechanism for multiple developing units |
US5282002A (en) | 1992-12-03 | 1994-01-25 | Eastman Kodak Company | Image forming apparatus having a sump component for multiple developing units |
US5376492A (en) | 1993-05-20 | 1994-12-27 | Eastman Kodak Company | Method and apparatus for developing an electrostatic image using a two component developer |
US5409791A (en) | 1993-05-20 | 1995-04-25 | Eastman Kodak Company | Image forming method and apparatus |
US5325161A (en) | 1993-05-24 | 1994-06-28 | Eastman Kodak Company | Device for developing an electrostatic image on an image member |
US5347347A (en) | 1993-05-25 | 1994-09-13 | Eastman Kodak Company | Apparatus for applying toner to an electrostatic image having improved developer flow |
US5592268A (en) | 1994-07-22 | 1997-01-07 | Brother Kogyo Kabushiki Kaisha | Mechanism to prevent toner leakage from an image forming unit |
US5512404A (en) | 1994-08-29 | 1996-04-30 | Eastman Kodak Company | Developer compositions exhibiting high development speeds |
US5500320A (en) | 1994-08-29 | 1996-03-19 | Eastman Kodak Company | High speed developer compositions with ferrite carriers |
US5648842A (en) | 1995-01-21 | 1997-07-15 | Ricoh Company, Ltd. | Methods and systems for cleaning residual toner from image-developing device |
US5705307A (en) | 1995-08-23 | 1998-01-06 | Eastman Kodak Company | Method of developing electrostatic images |
US5748218A (en) | 1996-01-17 | 1998-05-05 | Eastman Kodak Company | Method for forming toner images with two distinct toners |
US5713064A (en) | 1996-01-17 | 1998-01-27 | Eastman Kodak Company | Method and apparatus for forming toner images with two distinct toners |
US5701550A (en) | 1996-03-22 | 1997-12-23 | Eastman Kodak Company | Method and apparatus for controlling charge on toner in a toning station |
JP3535681B2 (en) * | 1996-12-04 | 2004-06-07 | キヤノン株式会社 | Image forming device |
US5853941A (en) | 1996-12-11 | 1998-12-29 | Eastman Kodak Company | Eliminating triboelectrically generated background in an electrophotographically produced image |
US5732311A (en) | 1996-12-26 | 1998-03-24 | Eastman Kodak Company | Compliant electrographic recording member and method and apparatus for using same |
US5923933A (en) * | 1997-02-21 | 1999-07-13 | Hitachi Koki Co., Ltd. | Electrophotographic apparatus |
US5835832A (en) | 1997-06-26 | 1998-11-10 | Eastman Kodak Company | Optimal toner charge for use with a compliant transfer intermediate |
US5926679A (en) | 1997-12-08 | 1999-07-20 | Eastman Kodak Company | Method and apparatus for forming an image for transfer to a receiver sheet using a clear toner and sintering of a pigmented toner layer |
US5998076A (en) | 1998-03-09 | 1999-12-07 | Xerox Corporation | Carrier |
US5923937A (en) | 1998-06-23 | 1999-07-13 | Eastman Kodak Company | Electrostatographic apparatus and method using a transfer member that is supported to prevent distortion |
US6610451B2 (en) * | 2000-12-26 | 2003-08-26 | Heidelberger Druckmaschinen Ag | Development systems for magnetic toners having reduced magnetic loadings |
US6728503B2 (en) * | 2001-02-28 | 2004-04-27 | Heidelberger Druckmaschinen Ag | Electrophotographic image developing process with optimized average developer bulk velocity |
US6946230B2 (en) * | 2001-11-13 | 2005-09-20 | Heidelberger Druckmaschinen Ag | Electrostatic image developing processes and compositions |
-
2001
- 2001-05-15 CA CA002374783A patent/CA2374783A1/en not_active Abandoned
- 2001-05-15 WO PCT/US2001/015574 patent/WO2001088628A1/en unknown
- 2001-05-15 EP EP01111750A patent/EP1156377B1/en not_active Expired - Lifetime
- 2001-05-15 AU AU2001263117A patent/AU2001263117A1/en not_active Abandoned
- 2001-05-15 US US09/855,384 patent/US6526247B2/en not_active Expired - Fee Related
- 2001-05-15 JP JP2001584960A patent/JP2003533748A/en active Pending
- 2001-05-15 DE DE60142147T patent/DE60142147D1/en not_active Expired - Lifetime
-
2003
- 2003-01-17 US US10/346,748 patent/US6775505B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
EP1156377B1 (en) | 2010-05-19 |
EP1156377A2 (en) | 2001-11-21 |
DE60142147D1 (en) | 2010-07-01 |
US6775505B2 (en) | 2004-08-10 |
EP1156377A3 (en) | 2004-11-10 |
WO2001088628A1 (en) | 2001-11-22 |
JP2003533748A (en) | 2003-11-11 |
AU2001263117A1 (en) | 2001-11-26 |
US20010043822A1 (en) | 2001-11-22 |
US6526247B2 (en) | 2003-02-25 |
US20030175053A1 (en) | 2003-09-18 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
FZDE | Discontinued |