CA2082416C - Organic photoconductor - Google Patents
Organic photoconductor Download PDFInfo
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- CA2082416C CA2082416C CA002082416A CA2082416A CA2082416C CA 2082416 C CA2082416 C CA 2082416C CA 002082416 A CA002082416 A CA 002082416A CA 2082416 A CA2082416 A CA 2082416A CA 2082416 C CA2082416 C CA 2082416C
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- Prior art keywords
- photoconductor
- photoconductive layer
- organic photoconductor
- photoconductive
- layer
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Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/02—Charge-receiving layers
- G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/005—Materials for treating the recording members, e.g. for cleaning, reactivating, polishing
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/02—Charge-receiving layers
- G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
- G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/10—Bases for charge-receiving or other layers
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/14—Inert intermediate or cover layers for charge-receiving layers
- G03G5/147—Cover layers
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/14—Inert intermediate or cover layers for charge-receiving layers
- G03G5/147—Cover layers
- G03G5/14708—Cover layers comprising organic material
- G03G5/14713—Macromolecular material
- G03G5/14747—Macromolecular material obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- G03G5/1476—Other polycondensates comprising oxygen atoms in the main chain; Phenol resins
Abstract
An organic photoconductor including a base layer formed of a first material and a photoconductive layer formed of a second material. The organic photoconductor being characterized in that when it is maintained in a curved orientation with the photoconductive layer facing outward, the photoconductive layer is subjected to less strees than the base layer. In one embodiment the first material is relatively more flexible and stretchable than said second material and the materials are pre-stressed in opposite senses. In a second embodiment the first material is relatively flexible and stretchable and the second material is an initially less flexible and stretchable material which has been chemically treated to increase its stretchability and flexibility.
Description
2Q~241~, '~U 91/17485 _ 1 _ PCT/NL90/00066 3 The present invention relates to photoconductors 4 generally and more particularly to organic photoconductors.
BACRGROUND OF THE INVENTION
6 Various types of organic photoconductors are known.
7 Most organic photoconductors are susceptible to attack by 8 organic solvents of the type used in liquid toner 9 electrophotography and are therefore unsuitable for such applications. These photoconductors include those which 11 dissolve in the solvents and others which are caused to 12 crack as the result of exposure thereto when they are under 13 stress, especially when under tension.
14 It is known in the art to provide protective coatings for organic photoconductors. Examples of these coatings are 16 given in U.S. Patents 4,891,290 and 4,894,304.
18 The present invention seeks to provide an improved 19 organic photoconductor which is resistant to cracking in a stressed environment wherein organic solvents of the type 21 used in liquid toner electrophotography are present.
22 There is thus provided in accordance with a preferred 23 embodiment of the present invention an organic 24 photoconductor including a base layer formed of a first material and a photoconductive layer formed of a second 26 material, the organic photoconductor being characterized in 27 that when it is maintained in a curved orientation with the 28 photoconductive layer facing outward, the photoconductive 29 layer is subjected to less stress than the base layer. In accordance with a preferred embodiment of the invention the 31 first material is relatively more flexible than the second 32 material. In accordance with an alternative preferred 33 embodiment of the invention the first material is relatively 34 flexible and stretchable and the second material is an initially less flexible and stretchable material, which has 36 been chemically treated to increase its stretchability and 37 flexibility.
38 There is also provided in accordance with a preferred 5 2 0 8 2 4 i 6 _ 2 _ PCT/NL90/0006' 1 embodiment of the present invention an organic 2 photoconductor including a base layer formed of a first 3 material and a photoconductive layer formed of a second 4 material, the base and photoconductive layers being pre-stressed in opposite senses.
BACRGROUND OF THE INVENTION
6 Various types of organic photoconductors are known.
7 Most organic photoconductors are susceptible to attack by 8 organic solvents of the type used in liquid toner 9 electrophotography and are therefore unsuitable for such applications. These photoconductors include those which 11 dissolve in the solvents and others which are caused to 12 crack as the result of exposure thereto when they are under 13 stress, especially when under tension.
14 It is known in the art to provide protective coatings for organic photoconductors. Examples of these coatings are 16 given in U.S. Patents 4,891,290 and 4,894,304.
18 The present invention seeks to provide an improved 19 organic photoconductor which is resistant to cracking in a stressed environment wherein organic solvents of the type 21 used in liquid toner electrophotography are present.
22 There is thus provided in accordance with a preferred 23 embodiment of the present invention an organic 24 photoconductor including a base layer formed of a first material and a photoconductive layer formed of a second 26 material, the organic photoconductor being characterized in 27 that when it is maintained in a curved orientation with the 28 photoconductive layer facing outward, the photoconductive 29 layer is subjected to less stress than the base layer. In accordance with a preferred embodiment of the invention the 31 first material is relatively more flexible than the second 32 material. In accordance with an alternative preferred 33 embodiment of the invention the first material is relatively 34 flexible and stretchable and the second material is an initially less flexible and stretchable material, which has 36 been chemically treated to increase its stretchability and 37 flexibility.
38 There is also provided in accordance with a preferred 5 2 0 8 2 4 i 6 _ 2 _ PCT/NL90/0006' 1 embodiment of the present invention an organic 2 photoconductor including a base layer formed of a first 3 material and a photoconductive layer formed of a second 4 material, the base and photoconductive layers being pre-stressed in opposite senses.
6 There is further provided in accordance with a 7 preferred embodiment of the present invention an organic 8 photoconductor including a base layer formed of a first 9 material and a photoconductive layer formed of a second material, the second material being chemically treated to 11 relieve stress therein. In a preferred embodiment of the 12 invention, the chemical treatment causes the photoconductive 13 layer to become more flexible and stretchable. Preferably 14 the photoconductive layer becomes more elastic or plastic.
Additionally in accordance with a preferred embodiment 16 of the present invention there is provided a method for 17 manufacturing an organic photoconductor including the steps 18 of 19 providing an organic photoconductor having a base layer and a photoconductor layer, and 21 treating at least one of the base layer and 22 photoconductive layer to relieve stress in the 23 photoconductive layer.
24 Additionally in accordance with the above embodiment of the invention, the base layer of the organic photoconductor 26 has greater flexibility and stretchability than the 27 photoconductor layer.
28 Further in accordance with the above embodiment of the 29 invention, the base layer has a stress relief temperature higher than that of the photoconductive layer.
31 Additionally in accordance with the preceding 32 embodiment, the step of treating includes the steps of 33 stressing the base layer and the photoconductive layer and 34 while they are stressed, heating them to a temperature between the stress relief temperatures of the base layer and 36 photoconductive layer.
37 In accordance with an alternative embodiment of the 38 invention, the step of treating includes the step of 2os~~~~
WO 91/17485 - 3 ~ PCT/NL90/00066 1 chemically treating the photoconductive layer to soften and 2 render it more elastic or plasi:ic that it previously was.
3 Additionally in accordancea with a preferred embodiment 4 of the invention there is provided a liquid toner electrophotographic system including a drum, a 6 photoconductive surface providE:d on the drum, apparatus for 7 forming a latent image on t:he photoconductive surface, 8 apparatus for liquid toner de~relopment of the latent image 9 on the photoconductive surface and apparatus for transferring the image after deavelopment thereof to a final 11 substrate, the photoconductive surface comprising an organic 12 photoconductor sheet mounted onto the drum.
13 In accordance with a preferred embodiment of the 14 invention, the photoconductor sheet is constructed and operative in accordance with any of the embodiments 16 described above, alone or in suitable combination.
WO 91/17485 _ 4 _ PCT/NL90/00066 1 BRIEF DE8C1~IPTION OF THE DRAWINGS
2 The present invention will be understood and 3 appreciated more fully from the following detailed 4 description, taken in conjunction with the drawings in which:
6 Fig. 1 is a simplified sectional illustration of liquid 7 toner electrophotographic apparatus constructed and 8 operative in accordance with a preferred embodiment of the 9 present invention;
Fig. 2 is a simplified illustration of an organic 11 photoconductor sheet useful in the embodiment of Fig. 1: and 12 Fig. 3 is a detailed illustration of pre-stressing of 13 the photoconductor in accordance with an embodiment of the 14 present invention.
DETAINED DESCRIPTION OF PREFERRED EMBODIMENT
16 Reference is now made to Fig. 1 which illustrates 17 liquid toner electrophotographic imaging apparatus 18 constructed and operative in accordance with a preferred 19 embodiment of the present invention. The invention is described for liquid developer systems with negatively 21 charged toner particles, and negatively charged 22 photoconductors, i.e., systems operating in the reversal 23 mode. For other combinations of toner particle and 24 photoconductor polarity, the values and polarities of the voltages are changed, in accordance with the principles of 26 the invention.
27 The invention can be practiced using a variety of 28 liquid developer types but is especially useful for liquid 29 developers comprising carrier liquid and pigmented polymeric toner particles. In a preferred embodiment of the 31 invention the carrier liquid is a solvent such as Isopar 32 (Exxon). Examples of such developers are given in U. S.
33 Patent 4,794,651, the disclosure of which is included herein 34 by reference.
As in conventional electrophotographic systems, the 36 apparatus of Fig. 1 typically comprises a drum 10 arranged 37 for rotation about an axle 12 in a direction generally 38 indicated by arrow 14. An organic photoconductor 100 is ~4 91/17485 2 0 8 2 416 _ 5 _ PCT/NL90/00066 1 mounted on the drum and :.s stretched tight by stretchers 99.
2 A corona discharge device 18 is operative to generally 3 uniformly charge organic photoconductor 100 with a negative 4 charge. Continued rotation of drum 10 brings charged organic photoconductor 100 into image receiving relationship with an 6 exposure unit including a lens 20, which focuses an image 7 onto charged organic photoconductor 100, selectively 8 discharging the photoconductor, thus producing an 9 electrostatic latent image 'thereon. The latent image comprises image areas at a given range of potentials and 11 background areas at a different potential. The image may be 12 laser generated as in printing :from a computer or it may be 13 the image of an original as in .a copier.
14 Continued rotation of drum 10 brings charged photoconductor 100, bearing the electrostatic latent image, 16 into a development unit 22 :including charged developer 17 plates 24. Development unit 22 :is operative to apply liquid 18 developer, comprising a solids portion including pigmented 19 toner particles and a liquid portion including carrier liquid preferably an organic liquid, to develop the 21 electrostatic latent image. Tlae developed image includes 22 image areas having pigmented toner particles thereon and 23 background areas.
24 While development unit 22 is shown as a single color developer of a conventional type, it may be replaced by a 26 plurality of single color developers for the production of 27 full color images as is known in the art. Alternatively, 28 full color images may be produced by changing the liquid 29 toner in the development unit when the color to be printed is changed. Alternatively, highlight color development may 31 be employed, as is known in the art.
32 In accordance with a preferred embodiment of the 33 invention, following application of toner thereto, 34 photoconductor 100 passes a typically charged rotating roller 26, preferably rotating in a direction indicated by 36 an arrow 28. Typically the spal:ial separation of roller 26 37 from photoconductor 100 is about 50 microns. Roller 26 thus 38 acts as a metering roller as is known in the art, reducing the amount of carrier liquid on the background areas and reducing the amount of liquid overlaying the image.
Preferably the potential on roller 26 is intermediate that of the latent image areas and of the background areas on the photoconductor. Typical approximate voltages are:
roller 26: -200 V to -800 V, background area: -1000 V and latent image areas: -150 V.
The liquid toner image which passes roller 26 should be relatively free of pigmented particles except in the region of the latent image.
Downstream of roller 26 there is preferably provided a rigidizing roller 30.
Rigidizing roller 30 is preferably formed of resilient polymeric material, such as polyurethane which may have only its natural conductivity or which may be filled with carbon black to increase its conductivity.
According to one embodiment of the invention, roller 30 is urged against photoconductor 100 as by a spring mounting (not shown). The surface of roller typically moves in the same direction and with the same velocity as the photoconductor surface to remove liquid from the image.
Preferably, the biassed squeegee described in U.S. Patent No. 4,286,039, is used as the roller 30. Roller 30 is biassed to a potential of at least several hundred and up to several thousand Volts with respect to the potential o the developed image on photoconductor 100, so that it repels the charged pigmented particles and causes them to more closely approach the image areas of photoconductor 100, thus compacting and rigidizing the image.
In a preferred embodiment of the invention, rigidizing roller 30 comprises an aluminum core having a 20 mm diameter, coated with a 4 mm thick carbon-filled polyurethane coating having a Shore A hardness of about 30-35, and avolume resistivity of about 10g ohm-cm. Preferably roller 30 is urged against photoconductor 100 with a pressure of about 40-70 grams per linear cm of contact, which extends along the length of the drum. The core of rigidizing roller 30 is energized to between about -1800 and ED0~2~~.~i WO 91/17485 - 7 ._ PCT/NL90/00066 1 -2800 volts, to provide a voli~age difference of preferably 2 between about 1600 and 2700 volts between the core and the 3 photoconductor surface in the image areas.
4 Under these conditions and for the preferred toner, the solids percentage in the image portion is believed to be as 6 high as 35% or more. It is prei'erable to have an image with 7 at least 25-30% solids, after rigidizing.
8 Downstream of rigidizing roller 30 there is provided 9 apparatus for direct transfer- of the image from organic photoconductor 100 to a substrate 130 such as paper. The 11 direct transfer is effected by the provision of guide 12 rollers 132, 134 and 136, which guide a continuous web of 13 substrate 130, and a drive roller 138, which cooperates with 14 a support web 140. A suitab7.e charging device, such as corona discharge device 142, charges the substrate at a 16 transfer location, for effecting electrophoretic transfer of 17 the image from photoconductor 100 to substrate 130.
18 Following transfer of the toner image to substrate 130, 19 photoconductor 100 is engaged by a cleaning roller 50, which typically rotates in a direction indicated by an arrow 52, 21 such that its surface moves in a direction opposite to the 22 movement of adjacent surface of: photoconductor 100 which it 23 operatively engages. Cleaning roller 50 is operative to 24 scrub and clean photoconductor 100. A cleaning material, such as toner or another cleaning solvent, may be supplied 26 to the cleaning roller 50, via a conduit 54. A wiper blade 27 56 completes the cleaning of the photoconductor surface. Any 28 residual charge left on photoconductor 100 is removed by 29 flooding the photoconductor surface with light from a lamp 58.
31 In a multi-color system, subsequent to completion of 32 the cycle for one color the cycle is sequentially repeated 33 for other colors which are sequentially transferred from 34 photoconductor 100 to substrate: 130.
Alternatively the direct. transfer apparatus may be 36 replaced by an intermediate transfer member which receives 37 the images from photoconductor 100 and transfers them to the 38 final substrate.
~0~~~~
1 Fig. 2 illustrates a preferred organic photoconductor 2 sheet 100, useful in the embodiment of Fig. 1. The sheet 3 comprises a base layer 102, typically formed of Aluminized 4 Polyethylene Telephthalate, which is commercially available under the trademark Mylar. The base layer is preferably 6 about 80 microns in thickness and has a melting point of 7 250" C.
8 Disposed above the base layer 102 is a sublayer 104, 9 typically formed of Polyester, Toluenesulfonamide formaldehyde resin and Polyamide and having a thickness of 11 about 0.2 microns. Disposed above the sublayer 104 is a 12 charge generation layer 106, typically formed of 13 Hydroxysquarylium Dye and Toluenesulfonamide-resin and 14 having a thickness of about 0.3 microns.
Disposed above layer 106 is a charge transport layer 16 108, typically formed of Polyester, Polycarbonate, Yellow 17 Dye, 4-[N,N-diethylamino] benzaldehydedipenylhydrazone and 18 Polysiloxane in a minor proportion, having a thickness of 19 about 18 microns. Charge transport layer 108 and charge generation layer 106 together define the photoconductive 21 layer referred to above.
22 The organic photoconductor described so far is 23 commercially available from IBM Corporation under the trade 24 name Emerald.
In accordance with an embodiment of the present 26 invention, and as illustrated in Fig. 3, the organic 27 photoconductor, as received from IBM Corporation, is 28 subjected to an annealing procedure which will now be 29 described in detail.
According to one embodiment of the invention, organic 31 photoconductor 100 is mounted on a stretcher 120 and 32 tensioned to a strain of 3 Kg per cm of width of 33 photoconductor 100. While subject to the above strain, 34 photoconductor 100 is heated, preferably in an oven (not shown) to a temperature of 60° C, for about 30 minutes.
36 Thereafter, photoconductor 100 is cooled to room temperature 37 and thereafter, the external stress is removed therefrom.
38 It is noted that the temperature of 60 degrees lies 20~~~~.
WO 91/17485 _ 9 ,_ PCT/NL90/00t166 1 intermediate the stres;~ relief temperature of base layer 2 102, which is approximately 150° C and the glass transition 3 temperature of charge transport layer 108, which is 4 approximately 45° C.
After treatment in the m<inner described above, i.e., 6 after the external stres:a is removed from sheet 7 photoconductor 100, charge transport layer 108 of 8 photoconductor 100 remains stressed under compression, while 9 base layer 102 remains stressed under tension. When photoconductor 100 is mounted on drum 10 as illustrated in il Fig. l, and subject to external tension, charge transport 12 layer 108 is either in compression or becomes relatively 13 free of stress, and therefore is less susceptible to 14 cracking or other defect geaneration as the result of exposure to organic solvents,, such as Isopar, which are 16 common in a liquid toner electrophotographic environment.
17 For example, an organic photoconductor 100 which was 18 not annealed as described above, developed cracks after 19 about 500 copy cycles in a liquid toner copier. In contrast, an organic photoconductor which was treated as described 21 above developed no cracks, even after several tens of 22 thousands of copy cycles. It should be noted that annealing 23 the sheet photoconductor without subjecting it to 24 simultaneous tension does noi: substantially improve the Isopar resistance of the photoconductor.
26 In accordance with an a:Lternative embodiment of the 27 present invention, organic phoi~oconductor 100 may be treated 28 chemically to reduce stress cracking in a liquid toner 29 environment. In accordance with this embodiment, the charge transport layer is treated wii~h a solvent or other reagent 31 to soften charge transport layer 108 and to render it more 32 stretchable, i.e., more pla:~tic or elastic than it was 33 previously.
34 The chemical treatment is selected so as to leave the electrical and optical characteristics of the photoconductor 36 essentially unchanged. When such a chemically treated 37 photoconductor sheet is stretched around drum 10, stress 38 does not develop in charge transport layer 108. Accordingly, ~a~~"~-_ ~.
w ~~ .~ i) WO 91/17485 _ 10 _ PCT/NL90/00066 1 when stretched photoconductoi- 100 is exposed to organic 2 solvents it does not tend to crack.
3 A specific chemical treatment which has been found to 4 be effective is dipping of photoconductor 10o in cyclohexanone diluted by isopropyl alcohol in the ratio 1:5 6 for 2 minutes. This treatment does not significantly change 7 the electrical and optica7L characteristics of the 8 photoconductor but eliminates cracking as described above.
9 An alternative chemical t~.~eatment employs cyclohexanone alone or vinyl modified epoxy 1A24, commercially available 11 from HumiSeal Division of Co:Lumbia Chase Corporation of 12 Woodside, NY, diluted 1:20 with cyclohexanone. These 13 materials can be applied by a wire-rod technique on the top 14 surface of photoconductor 100. In such a case, an RK Print-Coat Instrument Ltd. of Litl:ington, Royston, Merts., UK, 16 Model KCC 303 coater, using bar #2 (rod diameter 13 mm, wire 17 diameter 0.15 mm) may be operated with bar linear speed of 18 70 mm/sec.
19 If pure cyclohexanone i:a used, then the results are similar to those for dipping, and the solvent evaporates 21 within about 20-30 seconds.
22 If the mixture of cyclohexanone and epoxy is used, 23 then in addition to the above described effects of the 24 cyclohexanone, the residual vinyl modified epoxy forms a mechanically protective overcoating which is substantially 26 abhesive to toner particles rafter the evaporation of the 27 solvent.
28 It will be appreciated b:y persons skilled in the art 29 that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the 31 scope of the present invention is defined only by the claims 32 which follow:
Additionally in accordance with a preferred embodiment 16 of the present invention there is provided a method for 17 manufacturing an organic photoconductor including the steps 18 of 19 providing an organic photoconductor having a base layer and a photoconductor layer, and 21 treating at least one of the base layer and 22 photoconductive layer to relieve stress in the 23 photoconductive layer.
24 Additionally in accordance with the above embodiment of the invention, the base layer of the organic photoconductor 26 has greater flexibility and stretchability than the 27 photoconductor layer.
28 Further in accordance with the above embodiment of the 29 invention, the base layer has a stress relief temperature higher than that of the photoconductive layer.
31 Additionally in accordance with the preceding 32 embodiment, the step of treating includes the steps of 33 stressing the base layer and the photoconductive layer and 34 while they are stressed, heating them to a temperature between the stress relief temperatures of the base layer and 36 photoconductive layer.
37 In accordance with an alternative embodiment of the 38 invention, the step of treating includes the step of 2os~~~~
WO 91/17485 - 3 ~ PCT/NL90/00066 1 chemically treating the photoconductive layer to soften and 2 render it more elastic or plasi:ic that it previously was.
3 Additionally in accordancea with a preferred embodiment 4 of the invention there is provided a liquid toner electrophotographic system including a drum, a 6 photoconductive surface providE:d on the drum, apparatus for 7 forming a latent image on t:he photoconductive surface, 8 apparatus for liquid toner de~relopment of the latent image 9 on the photoconductive surface and apparatus for transferring the image after deavelopment thereof to a final 11 substrate, the photoconductive surface comprising an organic 12 photoconductor sheet mounted onto the drum.
13 In accordance with a preferred embodiment of the 14 invention, the photoconductor sheet is constructed and operative in accordance with any of the embodiments 16 described above, alone or in suitable combination.
WO 91/17485 _ 4 _ PCT/NL90/00066 1 BRIEF DE8C1~IPTION OF THE DRAWINGS
2 The present invention will be understood and 3 appreciated more fully from the following detailed 4 description, taken in conjunction with the drawings in which:
6 Fig. 1 is a simplified sectional illustration of liquid 7 toner electrophotographic apparatus constructed and 8 operative in accordance with a preferred embodiment of the 9 present invention;
Fig. 2 is a simplified illustration of an organic 11 photoconductor sheet useful in the embodiment of Fig. 1: and 12 Fig. 3 is a detailed illustration of pre-stressing of 13 the photoconductor in accordance with an embodiment of the 14 present invention.
DETAINED DESCRIPTION OF PREFERRED EMBODIMENT
16 Reference is now made to Fig. 1 which illustrates 17 liquid toner electrophotographic imaging apparatus 18 constructed and operative in accordance with a preferred 19 embodiment of the present invention. The invention is described for liquid developer systems with negatively 21 charged toner particles, and negatively charged 22 photoconductors, i.e., systems operating in the reversal 23 mode. For other combinations of toner particle and 24 photoconductor polarity, the values and polarities of the voltages are changed, in accordance with the principles of 26 the invention.
27 The invention can be practiced using a variety of 28 liquid developer types but is especially useful for liquid 29 developers comprising carrier liquid and pigmented polymeric toner particles. In a preferred embodiment of the 31 invention the carrier liquid is a solvent such as Isopar 32 (Exxon). Examples of such developers are given in U. S.
33 Patent 4,794,651, the disclosure of which is included herein 34 by reference.
As in conventional electrophotographic systems, the 36 apparatus of Fig. 1 typically comprises a drum 10 arranged 37 for rotation about an axle 12 in a direction generally 38 indicated by arrow 14. An organic photoconductor 100 is ~4 91/17485 2 0 8 2 416 _ 5 _ PCT/NL90/00066 1 mounted on the drum and :.s stretched tight by stretchers 99.
2 A corona discharge device 18 is operative to generally 3 uniformly charge organic photoconductor 100 with a negative 4 charge. Continued rotation of drum 10 brings charged organic photoconductor 100 into image receiving relationship with an 6 exposure unit including a lens 20, which focuses an image 7 onto charged organic photoconductor 100, selectively 8 discharging the photoconductor, thus producing an 9 electrostatic latent image 'thereon. The latent image comprises image areas at a given range of potentials and 11 background areas at a different potential. The image may be 12 laser generated as in printing :from a computer or it may be 13 the image of an original as in .a copier.
14 Continued rotation of drum 10 brings charged photoconductor 100, bearing the electrostatic latent image, 16 into a development unit 22 :including charged developer 17 plates 24. Development unit 22 :is operative to apply liquid 18 developer, comprising a solids portion including pigmented 19 toner particles and a liquid portion including carrier liquid preferably an organic liquid, to develop the 21 electrostatic latent image. Tlae developed image includes 22 image areas having pigmented toner particles thereon and 23 background areas.
24 While development unit 22 is shown as a single color developer of a conventional type, it may be replaced by a 26 plurality of single color developers for the production of 27 full color images as is known in the art. Alternatively, 28 full color images may be produced by changing the liquid 29 toner in the development unit when the color to be printed is changed. Alternatively, highlight color development may 31 be employed, as is known in the art.
32 In accordance with a preferred embodiment of the 33 invention, following application of toner thereto, 34 photoconductor 100 passes a typically charged rotating roller 26, preferably rotating in a direction indicated by 36 an arrow 28. Typically the spal:ial separation of roller 26 37 from photoconductor 100 is about 50 microns. Roller 26 thus 38 acts as a metering roller as is known in the art, reducing the amount of carrier liquid on the background areas and reducing the amount of liquid overlaying the image.
Preferably the potential on roller 26 is intermediate that of the latent image areas and of the background areas on the photoconductor. Typical approximate voltages are:
roller 26: -200 V to -800 V, background area: -1000 V and latent image areas: -150 V.
The liquid toner image which passes roller 26 should be relatively free of pigmented particles except in the region of the latent image.
Downstream of roller 26 there is preferably provided a rigidizing roller 30.
Rigidizing roller 30 is preferably formed of resilient polymeric material, such as polyurethane which may have only its natural conductivity or which may be filled with carbon black to increase its conductivity.
According to one embodiment of the invention, roller 30 is urged against photoconductor 100 as by a spring mounting (not shown). The surface of roller typically moves in the same direction and with the same velocity as the photoconductor surface to remove liquid from the image.
Preferably, the biassed squeegee described in U.S. Patent No. 4,286,039, is used as the roller 30. Roller 30 is biassed to a potential of at least several hundred and up to several thousand Volts with respect to the potential o the developed image on photoconductor 100, so that it repels the charged pigmented particles and causes them to more closely approach the image areas of photoconductor 100, thus compacting and rigidizing the image.
In a preferred embodiment of the invention, rigidizing roller 30 comprises an aluminum core having a 20 mm diameter, coated with a 4 mm thick carbon-filled polyurethane coating having a Shore A hardness of about 30-35, and avolume resistivity of about 10g ohm-cm. Preferably roller 30 is urged against photoconductor 100 with a pressure of about 40-70 grams per linear cm of contact, which extends along the length of the drum. The core of rigidizing roller 30 is energized to between about -1800 and ED0~2~~.~i WO 91/17485 - 7 ._ PCT/NL90/00066 1 -2800 volts, to provide a voli~age difference of preferably 2 between about 1600 and 2700 volts between the core and the 3 photoconductor surface in the image areas.
4 Under these conditions and for the preferred toner, the solids percentage in the image portion is believed to be as 6 high as 35% or more. It is prei'erable to have an image with 7 at least 25-30% solids, after rigidizing.
8 Downstream of rigidizing roller 30 there is provided 9 apparatus for direct transfer- of the image from organic photoconductor 100 to a substrate 130 such as paper. The 11 direct transfer is effected by the provision of guide 12 rollers 132, 134 and 136, which guide a continuous web of 13 substrate 130, and a drive roller 138, which cooperates with 14 a support web 140. A suitab7.e charging device, such as corona discharge device 142, charges the substrate at a 16 transfer location, for effecting electrophoretic transfer of 17 the image from photoconductor 100 to substrate 130.
18 Following transfer of the toner image to substrate 130, 19 photoconductor 100 is engaged by a cleaning roller 50, which typically rotates in a direction indicated by an arrow 52, 21 such that its surface moves in a direction opposite to the 22 movement of adjacent surface of: photoconductor 100 which it 23 operatively engages. Cleaning roller 50 is operative to 24 scrub and clean photoconductor 100. A cleaning material, such as toner or another cleaning solvent, may be supplied 26 to the cleaning roller 50, via a conduit 54. A wiper blade 27 56 completes the cleaning of the photoconductor surface. Any 28 residual charge left on photoconductor 100 is removed by 29 flooding the photoconductor surface with light from a lamp 58.
31 In a multi-color system, subsequent to completion of 32 the cycle for one color the cycle is sequentially repeated 33 for other colors which are sequentially transferred from 34 photoconductor 100 to substrate: 130.
Alternatively the direct. transfer apparatus may be 36 replaced by an intermediate transfer member which receives 37 the images from photoconductor 100 and transfers them to the 38 final substrate.
~0~~~~
1 Fig. 2 illustrates a preferred organic photoconductor 2 sheet 100, useful in the embodiment of Fig. 1. The sheet 3 comprises a base layer 102, typically formed of Aluminized 4 Polyethylene Telephthalate, which is commercially available under the trademark Mylar. The base layer is preferably 6 about 80 microns in thickness and has a melting point of 7 250" C.
8 Disposed above the base layer 102 is a sublayer 104, 9 typically formed of Polyester, Toluenesulfonamide formaldehyde resin and Polyamide and having a thickness of 11 about 0.2 microns. Disposed above the sublayer 104 is a 12 charge generation layer 106, typically formed of 13 Hydroxysquarylium Dye and Toluenesulfonamide-resin and 14 having a thickness of about 0.3 microns.
Disposed above layer 106 is a charge transport layer 16 108, typically formed of Polyester, Polycarbonate, Yellow 17 Dye, 4-[N,N-diethylamino] benzaldehydedipenylhydrazone and 18 Polysiloxane in a minor proportion, having a thickness of 19 about 18 microns. Charge transport layer 108 and charge generation layer 106 together define the photoconductive 21 layer referred to above.
22 The organic photoconductor described so far is 23 commercially available from IBM Corporation under the trade 24 name Emerald.
In accordance with an embodiment of the present 26 invention, and as illustrated in Fig. 3, the organic 27 photoconductor, as received from IBM Corporation, is 28 subjected to an annealing procedure which will now be 29 described in detail.
According to one embodiment of the invention, organic 31 photoconductor 100 is mounted on a stretcher 120 and 32 tensioned to a strain of 3 Kg per cm of width of 33 photoconductor 100. While subject to the above strain, 34 photoconductor 100 is heated, preferably in an oven (not shown) to a temperature of 60° C, for about 30 minutes.
36 Thereafter, photoconductor 100 is cooled to room temperature 37 and thereafter, the external stress is removed therefrom.
38 It is noted that the temperature of 60 degrees lies 20~~~~.
WO 91/17485 _ 9 ,_ PCT/NL90/00t166 1 intermediate the stres;~ relief temperature of base layer 2 102, which is approximately 150° C and the glass transition 3 temperature of charge transport layer 108, which is 4 approximately 45° C.
After treatment in the m<inner described above, i.e., 6 after the external stres:a is removed from sheet 7 photoconductor 100, charge transport layer 108 of 8 photoconductor 100 remains stressed under compression, while 9 base layer 102 remains stressed under tension. When photoconductor 100 is mounted on drum 10 as illustrated in il Fig. l, and subject to external tension, charge transport 12 layer 108 is either in compression or becomes relatively 13 free of stress, and therefore is less susceptible to 14 cracking or other defect geaneration as the result of exposure to organic solvents,, such as Isopar, which are 16 common in a liquid toner electrophotographic environment.
17 For example, an organic photoconductor 100 which was 18 not annealed as described above, developed cracks after 19 about 500 copy cycles in a liquid toner copier. In contrast, an organic photoconductor which was treated as described 21 above developed no cracks, even after several tens of 22 thousands of copy cycles. It should be noted that annealing 23 the sheet photoconductor without subjecting it to 24 simultaneous tension does noi: substantially improve the Isopar resistance of the photoconductor.
26 In accordance with an a:Lternative embodiment of the 27 present invention, organic phoi~oconductor 100 may be treated 28 chemically to reduce stress cracking in a liquid toner 29 environment. In accordance with this embodiment, the charge transport layer is treated wii~h a solvent or other reagent 31 to soften charge transport layer 108 and to render it more 32 stretchable, i.e., more pla:~tic or elastic than it was 33 previously.
34 The chemical treatment is selected so as to leave the electrical and optical characteristics of the photoconductor 36 essentially unchanged. When such a chemically treated 37 photoconductor sheet is stretched around drum 10, stress 38 does not develop in charge transport layer 108. Accordingly, ~a~~"~-_ ~.
w ~~ .~ i) WO 91/17485 _ 10 _ PCT/NL90/00066 1 when stretched photoconductoi- 100 is exposed to organic 2 solvents it does not tend to crack.
3 A specific chemical treatment which has been found to 4 be effective is dipping of photoconductor 10o in cyclohexanone diluted by isopropyl alcohol in the ratio 1:5 6 for 2 minutes. This treatment does not significantly change 7 the electrical and optica7L characteristics of the 8 photoconductor but eliminates cracking as described above.
9 An alternative chemical t~.~eatment employs cyclohexanone alone or vinyl modified epoxy 1A24, commercially available 11 from HumiSeal Division of Co:Lumbia Chase Corporation of 12 Woodside, NY, diluted 1:20 with cyclohexanone. These 13 materials can be applied by a wire-rod technique on the top 14 surface of photoconductor 100. In such a case, an RK Print-Coat Instrument Ltd. of Litl:ington, Royston, Merts., UK, 16 Model KCC 303 coater, using bar #2 (rod diameter 13 mm, wire 17 diameter 0.15 mm) may be operated with bar linear speed of 18 70 mm/sec.
19 If pure cyclohexanone i:a used, then the results are similar to those for dipping, and the solvent evaporates 21 within about 20-30 seconds.
22 If the mixture of cyclohexanone and epoxy is used, 23 then in addition to the above described effects of the 24 cyclohexanone, the residual vinyl modified epoxy forms a mechanically protective overcoating which is substantially 26 abhesive to toner particles rafter the evaporation of the 27 solvent.
28 It will be appreciated b:y persons skilled in the art 29 that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the 31 scope of the present invention is defined only by the claims 32 which follow:
Claims (16)
1. A method of manufacturing a photoconductor for use in an electrostatic imaging machine, including:
providing an organic photoconductor having a base layer and a photoconductive layer;
placing the photoconductor in a curved configuration, the photoconductive layer facing outward, wherein tension is applied to the photoconductive layer;
heat treating the stressed organic photoconductor to relieve stress in the photoconductive layer without relieving stress in the base layer;
releasing the organic photoconductor from the curved configuration after the organic photoconductor has cooled and prior to its use.
providing an organic photoconductor having a base layer and a photoconductive layer;
placing the photoconductor in a curved configuration, the photoconductive layer facing outward, wherein tension is applied to the photoconductive layer;
heat treating the stressed organic photoconductor to relieve stress in the photoconductive layer without relieving stress in the base layer;
releasing the organic photoconductor from the curved configuration after the organic photoconductor has cooled and prior to its use.
2. A method according to claim 1 wherein the base layer has a strain relief temperature higher than that of the photoconductive layer.
3. A method according to claim 1 or 2 wherein heat treating include:
heating the stressed organic photoconductor to a temperature between the stress relief temperatures of the base layer and photoconductive layer.
heating the stressed organic photoconductor to a temperature between the stress relief temperatures of the base layer and photoconductive layer.
4. A method according to claim 3 and also including:
cooling the base layer and photoconductive layer while they are stressed after the step of heat treating; and removing the external stress from the base layer and photoconductive layers without forming an image on the photoconductor.
cooling the base layer and photoconductive layer while they are stressed after the step of heat treating; and removing the external stress from the base layer and photoconductive layers without forming an image on the photoconductor.
5. A method of manufacturing a photoconductor including:
providing an organic photoconductor having a base layer and a photoconductive layer;
stressing the organic photoconductor;
heat treating the stressed organic photoconductor to relieve stress in the photoconductive layer without relieving the stress in the base layer;
cooling the organic photoconductor without removing the stress therefrom; and removing the external stress from the photoconductor prior to forming an image on the photoconductor.
providing an organic photoconductor having a base layer and a photoconductive layer;
stressing the organic photoconductor;
heat treating the stressed organic photoconductor to relieve stress in the photoconductive layer without relieving the stress in the base layer;
cooling the organic photoconductor without removing the stress therefrom; and removing the external stress from the photoconductor prior to forming an image on the photoconductor.
6. An organic photoconductor sheet comprising:
a base layer formed of a first material and a photoconductive layer formed of a second material, the base and photoconductive layers being stressed in opposite senses from each other, wherein the photoconductive layer is in compression.
a base layer formed of a first material and a photoconductive layer formed of a second material, the base and photoconductive layers being stressed in opposite senses from each other, wherein the photoconductive layer is in compression.
7. An organic photoconductor sheet comprising:
a base layer formed of a first material; and a photoconductive layer formed of a second material, the organic photoconductor being characterized in that when it is subjected to externally applied tension, the photoconductive layer is in compression.
a base layer formed of a first material; and a photoconductive layer formed of a second material, the organic photoconductor being characterized in that when it is subjected to externally applied tension, the photoconductive layer is in compression.
8. A method of treating a photoconductor including:
providing an organic photoconductor having a base layer and a photoconductive layer; and chemically treating with an organic solvent the photoconductive layer in the provided organic photoconductor to relieve stress in the photoconductive layer.
providing an organic photoconductor having a base layer and a photoconductive layer; and chemically treating with an organic solvent the photoconductive layer in the provided organic photoconductor to relieve stress in the photoconductive layer.
9. A method according to claim 8 wherein the base layer of the provided organic photoconductor has greater flexibility and stretchability then the photoconductive layer.
10. A method according to claim 8 or 9 wherein chemically treating includes softening the photoconductive layer to render it more elastic than it previously was.
11. A method according to any of claims 8 to 10 wherein treating includes softening the photoconductive layer to render it more plastic than it previously was.
12. A method according to any of claims 8 to 11 wherein chemically treating also includes forming a protective layer on the photoconductive layer.
13. A method according to claim 12 wherein the protective material is an vinyl modified epoxy.
14. A method according to any of claims 8 to 13 wherein the step of chemically treating comprises:
applying of a protective material in the organic solvent to the photoconductive layer whereby the solvent causes the photoconductive layer to soften and become more elastic; and allowing the solvent to evaporate to leave a protective coating on the photoconductive layer.
applying of a protective material in the organic solvent to the photoconductive layer whereby the solvent causes the photoconductive layer to soften and become more elastic; and allowing the solvent to evaporate to leave a protective coating on the photoconductive layer.
15. An organic photoconductor manufactured according to the method of any of claims 1 to 5 or 8 to 14.
16. A liquid toner electrophotographic system comprising:
a drum;
an organic photoconductor according to any of claims 6, 7 or 15, disposed on the surface of the drum;
means for forming a latent image on the photoconductive surface;
means for liquid toner development of the latent image on the photoconductive surface; and means for transferring the image after development thereof to a final substrate.
a drum;
an organic photoconductor according to any of claims 6, 7 or 15, disposed on the surface of the drum;
means for forming a latent image on the photoconductive surface;
means for liquid toner development of the latent image on the photoconductive surface; and means for transferring the image after development thereof to a final substrate.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/946,411 US5376491A (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
| PCT/NL1990/000066 WO1991017485A1 (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
| EP90908309A EP0527727B1 (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
| EP95202276A EP0690350B1 (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
| CA002082416A CA2082416C (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
| US08/325,501 US5527652A (en) | 1990-05-08 | 1994-10-19 | Organic photoconductor |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/NL1990/000066 WO1991017485A1 (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
| CA002082416A CA2082416C (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2082416A1 CA2082416A1 (en) | 1991-11-09 |
| CA2082416C true CA2082416C (en) | 2000-04-11 |
Family
ID=4150664
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002082416A Expired - Fee Related CA2082416C (en) | 1990-05-08 | 1990-05-08 | Organic photoconductor |
Country Status (3)
| Country | Link |
|---|---|
| US (2) | US5376491A (en) |
| EP (1) | EP0527727B1 (en) |
| CA (1) | CA2082416C (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6623902B1 (en) * | 1991-03-28 | 2003-09-23 | Hewlett-Packard Indigo B.V. | Liquid toner and method of printing using same |
| US5606396A (en) * | 1995-01-06 | 1997-02-25 | Xerox Corporation | Imaging process using flexible electrostatographic imaging member |
| EP0944861B2 (en) | 1996-12-03 | 2005-10-05 | Hewlett-Packard Indigo B.V. | Method and apparatus for cleaning an image transfer member |
| AU2105897A (en) | 1997-03-13 | 1998-09-29 | Indigo N.V. | Organic photoconductor and treatment therefor |
| US5885512A (en) * | 1997-10-01 | 1999-03-23 | Xerox Corporation | Method of treating preformed flexible imaging belts to form ripple-free and dimensionally precise belts |
| US6074504A (en) * | 1998-01-08 | 2000-06-13 | Xerox Corporation | Defocused laser seam stress release in flexible electrostatographic imaging member belts |
| US6056839A (en) * | 1998-01-08 | 2000-05-02 | Xerox Corporation | Rapid electrostatographic belt treatment system |
| US6068722A (en) * | 1998-01-08 | 2000-05-30 | Xerox Corporation | Seam stress release in flexible electrostatographic imaging belts |
| US6165670A (en) * | 1999-05-24 | 2000-12-26 | Xerox Corporation | Method of treating electrostatographic imaging web and method of making electrostatographic imaging members using such imaging web |
| CA2375624A1 (en) | 1999-07-05 | 2001-01-11 | Indigo N.V. | Printers and copiers with pre-transfer substrate heating |
| US6652691B1 (en) | 1999-10-28 | 2003-11-25 | Xerox Corporation | Seam stress release and protrusion elimination process |
| US6328922B1 (en) | 1999-10-28 | 2001-12-11 | Xerox Corporation | Process for post treatment of a flexible imaging member belt |
| US6861193B1 (en) | 2000-05-17 | 2005-03-01 | Hewlett-Packard Indigo B.V. | Fluorescent liquid toner and method of printing using same |
| US7410548B2 (en) * | 2005-08-26 | 2008-08-12 | Xerox Corporation | Flexible imaging member belt seam smoothing method |
| US7977023B2 (en) * | 2007-07-26 | 2011-07-12 | Hewlett-Packard Development Company, L.P. | Ink formulations and methods of making ink formulations |
| US8623582B2 (en) * | 2007-07-30 | 2014-01-07 | Hewlett-Packard Development Company, L.P. | Treatment for enhancing crack resistance of organic photoconductors |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1814644B2 (en) * | 1967-12-26 | 1976-09-02 | Fuji Shashin Film K.K., Ashigara, Kanagawa (Japan) | ELECTROPHOTOGRAPHIC RECORDING MATERIAL |
| DE1906969A1 (en) * | 1969-02-07 | 1970-08-20 | Matsushita Electric Ind Co Ltd | Flexible, transparent electrophotographic - recording material |
| US3717462A (en) * | 1969-07-28 | 1973-02-20 | Canon Kk | Heat treatment of an electrophotographic photosensitive member |
| US3764590A (en) * | 1970-04-08 | 1973-10-09 | Hitachi Ltd | Organic photoconductive materials |
| JPS4923905B1 (en) * | 1970-10-31 | 1974-06-19 | ||
| GB1603972A (en) * | 1978-02-15 | 1981-12-02 | Reed K J | Transfer sheets with releasable layers |
| US4286039A (en) * | 1979-05-15 | 1981-08-25 | Savin Corporation | Method and apparatus for removing excess developing liquid from photoconductive surfaces |
| DE3032773A1 (en) * | 1980-08-30 | 1982-05-06 | Hoechst Ag, 6000 Frankfurt | ELECTROPHOTOGRAPHIC RECORDING MATERIAL AND METHOD FOR THE PRODUCTION THEREOF |
| US4387146A (en) * | 1980-09-08 | 1983-06-07 | Eastman Kodak Company | Multicolor filters with nonplanar support elements |
| JPS599667A (en) * | 1982-07-09 | 1984-01-19 | Toray Ind Inc | Method for forming electrostatic latent image on electrophotographic receptor and on its photoreceptor |
| US4497566A (en) * | 1983-03-03 | 1985-02-05 | Eastman Kodak Company | Correction of image defects in photoconductive film |
| US4794651A (en) * | 1984-12-10 | 1988-12-27 | Savin Corporation | Toner for use in compositions for developing latent electrostatic images, method of making the same, and liquid composition using the improved toner |
| US4582773A (en) * | 1985-05-02 | 1986-04-15 | Energy Conversion Devices, Inc. | Electrophotographic photoreceptor and method for the fabrication thereof |
| JPS63188153A (en) * | 1987-01-30 | 1988-08-03 | Diafoil Co Ltd | Polyester film for holding electrophotographic sensitive layer |
| JPH0792610B2 (en) * | 1987-06-10 | 1995-10-09 | 富士電機株式会社 | Electrophotographic photoconductor |
| JP2595574B2 (en) * | 1987-11-06 | 1997-04-02 | ミノルタ株式会社 | Photoconductor |
| US5032481A (en) * | 1989-10-30 | 1991-07-16 | Eastman Kodak Company | Photoconductor elements with multiphase stress-dampening interlayers |
-
1990
- 1990-05-08 US US07/946,411 patent/US5376491A/en not_active Expired - Lifetime
- 1990-05-08 EP EP90908309A patent/EP0527727B1/en not_active Expired - Lifetime
- 1990-05-08 CA CA002082416A patent/CA2082416C/en not_active Expired - Fee Related
-
1994
- 1994-10-19 US US08/325,501 patent/US5527652A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US5527652A (en) | 1996-06-18 |
| CA2082416A1 (en) | 1991-11-09 |
| EP0527727A1 (en) | 1993-02-24 |
| EP0527727B1 (en) | 2000-09-06 |
| US5376491A (en) | 1994-12-27 |
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| EEER | Examination request | ||
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