US2776182A - Pictorial representation reproducing head - Google Patents

Description

Jan. 1, 1957 N. R. GUNDERSON PICTORIAL'REPRESENTATION REPRODUCING HEAD 2 Sheets-Sheet 1 Filed Feb. 9, 1953 135- 153 157 1.49 1 9a m 151 1 H6. 5: A/B H. GUNDEPSOM INVENTOR.

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Jan. 1, 1957 N. R. GUNDERSON PICTORIAL REPRESENTATION REPRODUCING HEAD Filed Feb. 9, 1953 United States Patent PICTORIAL REPRESENZEAATION REPRODUCENG HE D Norman R. Gunderson, Pasadena, (Zalif. Application February 9, 1953, Serial No. 335,733

3 Claims. (Cl. 346-75) This invention relates generally to reproducing heads adapted for use in making colored pictorial representations, facsimiles, or reproductions of colored subjects. More specifically, it relates to reproducing heads adapted to mix various colored inks and a black ink in accordance with electric signals corresponding to the various colored inks and the black ink, and to apply said mixed atomized inks upon succeeding small, elemental areas or points of a suitable medium, such as paper or the like (which may be mounted upon a suitably driven rotatable and axially movable drum) so that a reproduction in substantially natural colors (or desired colors) is obtained.

This application is a continuation-in-part of my parent copending application Serial No. 702,174, filed October 9, 1946, now Patent No. 2,628,150, issued February 10, 1953, and the reproducing heads described, illustrated and claimed herein are adapted for use in the system disclosed in my Patent No. 2,413,796 or in many other color reproduction systems, as will be apparent to those skilled in the art.

Prior art reproducing heads have numerous disadvantages. For example, most prior art reproducing heads have very slow response. In other words, the flow of the various inks lags, to a considerable extent, behind the corresponding electric signal, and if the electric signal is changing rapidly, the flow of the corresponding ink cannot follow the electric signal, and distortion results. Also, most prior art reproducing heads do not properly mix and atomize the inks whereas the reproducing heads of my invention have exceedingly fast accurate response with distortion minimized.

Generally speaking, my invention comprises: an air conduit provided with means for supplying air under pressure to said conduit; at least one nozzle provided with a fixed opening directed into the air stream from said air conduit; an ink conduit for supplying the nozzle with ink; and means for causing ink flow to the nozzle. The term ink, as used herein, includes any fluid solution dispersion or suspension adapted for use in the system.

In the preferred embodiments of my invention, I have employed three colored ink nozzles and a black ink nozzle; however, any desired number might be used.

In the present invention the means for causing ink flow to the nozzle above referred to comprises means for generating and modulating a high frequency oscillatory electric current in accordance with an electric signal corresponding to that colored ink, and applying said modulated high frequency current to the ink for heating and expanding same.

With the above points in mind:

It is an object of this invention to provide an improved reproducing head having an exceedingly fast response and a minimum of distortion.

It is a further object of this invention to provide an improved reproducing head having an exceedingly fast response and a minimum of distortion wherein the flow of ink is caused by electrically controlled heating and expansion of the ink.

Patented Jan. I, 1957 Other and allied objects will become apparent to those skilled in the art after a careful examination and perusal of the illustrations, specifications and claims appended hereto.

'For purpose of illustration reference will be had to the following drawings, of which:

Fig. 1 is a vertical sectional view of a preferred embodiment of my invention.

Fig. 2 is a top plan view of the embodiment shown in Fig. 1 with the top plate, nozzles and one of the ink reservoir wheels removed.

Fig. 3 is a vertical sectional view of a modified form of the invention.

Fig. 4 is a top plan view of the reproducing head shown in Fig. 3 with the top plate, nozzles and one of the ink reservoir wheels removed.

Fig. 5 is a wiring diagram schematically illustrating one form of modulator for use with the reproducing head of my invention.

i Fig. 6 is an isometric perspective view of an alternative embodiment of the invention with portions cut away on horizontal and vertical planes for clarity.

Fig. 7 is a perspective diagrammatic representation of the conduits and connections associated with a single nozzle of the reproducing head of Fig. 6.

Fig. 8 is a perspective view of the lower portion of the reproducing head of Fig. 6 with a section cut away.

Fig. 9 is a plan view of a modified arrangement of nozzles for use in the reproducing head.

Fig. 10 is a fragmentary vertical sectional view taken along the line XX of Fig. 9.

The reproducing head of this invention is adapted to be used in making colored facsimiles or reproductions. A more particularly pointed out in Patent No. 2,413,706, a plurality of color separation photographic images may be scanned by suitable scanning means, and electric signals generated by the scanning means may be modified in suitable ways. A signal corresponding to each color of inks to be used may then be applied to the apparatus of the present invention.

In the drawings a reproducing head having four nozzles is shown, three of these nozzles being adapted to supply colored inks, the fourth nozzle being associated with a source of black ink. In accordance with the present invention, the rate of feed of the inks through the nozzles is controlled in accordance with the variations in the electrical input signals to the reproducing head.

The reproducing head shown in Fig. l and Fig. 2 contains four ink reservoir wheels or rotatable members (one for each ink), three of which are shown as 41, 42 and 43 in Fig. 2. Each of these wheels is mounted for rotation by means of a shaft 44, 45, 46 and 47, which extends through the block 48 and has a driving gear mounted on the other end thereof such as gears 49 and 50 shown in Fig. 1, it being understood that the other two shafts are also provided with suitable driving gears. These four gears intermesh with each other so that if one shaft turns, the other must turn also. A suitable driving means is connected to the shaft 45 so that the four ink reservoir wheels may be rotated at a desired rate.

The holes in the ink reservoir wheels (best shown in Fig. 2) form the ink reservoirs or chambers and each ink reservoir or chamber is flushed out at each revolution with the corresponding ink. This is done as follows: Assuming that the ink reservoir wheel 43 rotates in a clockwise direction, the ink enters a port may be mentioned that a suitable pump such as a small U centrifugal or gear pump and a large ink reservoir may be provided for flushing the ink from each of the ink reservoir wheels. The ink in each of these large reservoirs is maintained at uniform temperature by suitable means. Such means are well known in the art and need not be shown.

Positioned around the four ink reservoir wheels and between the upper plate 53 and the lower block 48 is an annular ring 55 adapted to seal in and enclose the space containing the four ink reservoir wheels. Passing longitudinally through the lower block 48 and through the enclosed chamber containing the ink reservoir wheels and through the upper plate 53 is an air conduit 56 adapted to be supplied with air under pressure from suitable means not shown.

Positioned upon the upper plate 53 are four nozzles (two of which, and 53, are shown in Fig. 1 connected to tubes 59 and 60 which pass through the plate 53 to points opposite their ink reservoirs, it being understood that the other two nozzles are also provided with similar tubes and that all of said tubes may be capillary tubes). The nozzles are provided with tiny spray jets or orifices (having diameters of the order of 0.004 of an inch) and are inwardly directed toward the air stream emitted by theair conduit 56 so as to be atomized and mixed thereby. The atomized, mixed inks are then adapted to be sprayed onto a suitable medium such as paper or the like. Although the nozzles shown in Figs. l and 2 are pointed transversely to the air stream, other arrangements may be used such as, for example, that shown in Figs. 9 and 10 wherein the nozzles are upwardly extended into the air stream.

The flow of each ink to the corresponding nozzle or spray jet is caused by heating and expanding it by the passage of a high frequency alternating electric current. The ink reservoir wheels are made of an electrical insulator such as methyl methacrylate resin or other suitable material and the upper electrode for each wheel is the plate 53 which is made of metal or other suitable electrically conductive material. The lower block 48 is also preferably made of an insulating material such as methyl methacrylate resin, phenol-formaldehyde resin or other similar material.

Lower electrically conductive electrodes are mounted in the lower block 48 and are shown at 61, 62, 63 and 64. These electrodes are provided with insulated leads or connecting wires 65, 66, 67 and 63. The heating cycle for each reservoir is that portion of its path in which it is in contact with its corresponding electrodes. The upper plate 53 is slotted to correspond to the shape of electrodes 61, 62, 63 and 64- so that the ink chamber or reservoir is connected to its tube and to the spray jet of a nozzle during all parts of its heating cycle when the lower electrode is in contact with the ink. The flow of ink to the spray jet of the nozzle is then caused by passage. of the corresponding electric current. The flow is proportional to the rate of heating or to the current squared multiplied by the resistance, in which the current is the actual current passing through the ink in the ink chamber or reservoir and the resistance is the effective resistance between electrodes in the ink chamber or reservoir. This heating effect may be greatly increased by dissolving salt or the like in the ink for increasing the electrical conductivity thereof.

Due to the very short time of the heating cycle, the heat transfer from the ink to the walls of the container or chamber causes only a negligible change in fiow to the spray jet of the nozzle. Therefore, it should be emphasized that this system has very little time lag. In other words, it has an extremely fast response because there is no time lag in the rate of heating or the rate of flow of the ink behind the electric current passed therethrough. Also, since the electrical load is a resistive one, there can be no lag in current behind applied voltage due to inductive or capacitive effects. Practically all of the time lag in the flow will then be due to the compression of the liquid due to the change in pressure on the liquid occurring with changes of heating rate and changes in flow of the liquid. This effect can be reduced to a negligible value by making the volume of liquid connected to the spray jet of the nozzle suificiently small.

It should be noted that the effect of heating losses from the liquid to the container are minimized until they are negligible. This is done because the heating chamber is separate from the tube carrying the ink from the ink chamber to the spray jet of the nozzle. At the beginning of the heating cycle the temperature of the ink is the same as that of the ink chamber so that the heat transfer is zero. As the electric current is passed through the liquid and heat is generated in the liquid, the temperature of the liquid rises and the heat transfer from the liquid to the ink chamber becomes greater and greater. As soon as the temperature of the ink reaches a point at which the heat loss from the ink causes an appreciable error or reduction in the flow of the ink from the ink chamber, then the ink reservoir wheel will have revolved so that a new ink chamber is substituted for the old one. The ink in the ink chamber now has the same temperature as the walls of the ink chamber so that heat loss is zero and no error results from heat loss.

Although I have described the construction and operation of one ink reservoir, spray nozzle and associated elements, etc., corresponding to one ink channel, the description also applies to the other three ink reservoir wheels, spray nozzles and associated parts.

Fig. 5 illustrates one form of modulator for use with my invention. An input electric signal is applied to input terminal in Fig. 5. The input terminal 130 is connected to the grid 131 of the phase inverter tube 132. The cathode 133 of the phase inverter tube 132 is connected through a suitable cathode resistor 134 to negative power input terminal 135. The anode 136 of the phase inverter tube 132 is connected through a plate resistor 137 to positive power input terminal 138. The anode 136 of the phase inverter tube 132 is also connected through a resistor 139 to the control grids 140, 141, 142 and the anodes 143, 144 and 145, respectively, of electron tubes 146, 147, and 148, and through radio frequency transformer secondary winding 149 to the grid 150 of the modulator 151.

The before mentioned grids, anodes and oscillator transformer secondary winding are also connected through a resistor 152 to negative power input terminal 153. The cathode 154 of the electron tube 146 is connected to negative power input terminal 155. The cathode 156 of the electron tube 147 is connected to negative power input terminal 157. The cathode 158 of electron tube 148 is connected to negative power input terminal 159. The cathode 160 of the modulator tube 151 is connected to negative power input terminal 161.

The anode 162 of the modulator tube 151 is connected through the primary winding 163 of an output frequency transformer to positive power input terminal 164. The primary winding 165 of the oscillator radio frequency transformer has the opposite ends thereof connected to input terminals 166 and 167 which are adapted to be connected to a radio frequency oscillator which is not shown since such oscillators are well known in the art. The secondary Winding 168 of the output radio frequency transformer has the opposite ends thereof connected to output terminals 169 and 170 which are adapted to be connected to the upper and lower electrodes at the upper and lower ends of one ink chamber in the reproducing head. shown in Figs. 1 and 2.

Similar systems are utilized for each of the other ink channels. One essential requirement of the modulator is that it modulates the high frequency alternating voltage in such a way that the output voltage from the modulator is proportional to the square root of the input signal voltage. This is due to the fact that the heating effect S of the current passed through the ink in the reproducing head is proportional to the current squared times the resistance of the ink.

In the system shown in Fig. 5, the phase inverter tube 132 is used so as to cause the reproducing head to produce an increase in the flow of ink in response to a more negative input signal. The phase inverter tube maybe dispensed with entirely if it is desired to have the flow of ink from the reproducing head function oppositely from that described.

The electron tubes 146, 147 and 148 together form a virtually square root amplifier. Each of the tubes 146, 147 and 148 acts as a rectifier and draws current when its grid is more positive than its cathode. This causes a reduction in the rate of increase of grid voltage of the tubes 146, 147, 148 and the modulator tube 151 with constant rate of change of the grid voltage of the phase inverter tube 132. By adjusting the voltages of the cathodes 154, 156 and 158 of the three electron tubes 146, 147 and 148, respectively, to the proper values, a nonlinear amplification may be obtained which may be made to closely approximate a square root curve. Thus, the output at terminals 169 and 170 is a radio frequency alternating current so modulated that the heating efiect thereof will vary linearly with the input signal delivered to input terminal 130.

In Figs. 3 and 4 is shown a modified form of the invention heretofore described in connection with Figs. 1 and 2 wherein the upper plate 53' is somewhat deeper than the upper plate 53 of the embodiment shown in Figs. 1 and 2. The deep upper plate 53' includes outlet port 54, which corresponds in function to outlet port 54 of Figs. 1 and 2. In the embodiment of Figs. 3 and 4 it will be understood that during the flushing and replenishing portion of the cycle, ink enters inlet port 51' from a source of ink at a constant relatively low temperature, flows upwardly through the ink reservoir in'alignment with the inlet port, thence through channel 52' and outwardly through the aforementioned outlet port 54', which is desirably but not necessarily in vertical alignment with the inlet port 51'. Remaining components of the form of invention in Figs. 3 and 4 are indicated by primed reference characters corresponding to those of Figs. 1 and 2.

In the forms of the invention shown in Figs. 1, 2, 3 and 4, it will be understood that shaft 45 or 45' is caused to rotate at a relatively slow preferably constant speed by suitable means so that one or portions of two adjacent ink reservoirs are always electrically connected at their lower ends to contact 64 or 64' and at their upper ends in communication with the tube 60 or 60' and thus with nozzle 58 or 58.

Figs. 6, 7 and 8 illustrate an alternative embodiment of the invention wherein a single reciprocally rotatable ink reservoir wheel is provided to alford replenishing means for all four of the inks used. Such a circular member is best seen at 17 in Fig. 8, and is made of an insulating material such as methyl methacrylate resin, teflon or similar non-conductive substance chemically inert to inks being used. The member 17 is fixedly mounted upon the upper end of a tubular shaft 30 which is caused, intermittently, to rotate through a small angle, as will be later understood, for periodically bringing a fresh supply of ink into operative position. Extending through the hollow center of shaft 30 is a hollow air conduit 3 terminating at its upper end in an upwardly directed opening 31, and the conduit is adapted to be connected at its lower end to an air pump or other suitable source of air under pressure (not shown).

Circular member 17 is housed in a reproducing head including an upper block 1 and lower block 2 held in assembled relation by suitable means as shown in Fig. 6, and the blocks 1 and 2 are provided with nozzles, ports and conduits for ink passage. The upper block 1 is made of any suitable electrically conductive material such as metal and the lower block 2 is made of a nea conductive material (like rotatable member 17) such as tefion, methyl methacrylate resin or the like inert to the inks to be used.

There will now be described the nozzle, ports and conduits associated with the supply of only a single ink, it being understood that identical nozzles, ports and conduits are provided for inks of other colors to be used. As previously mentioned, the apparatus herein shown presupposes the use of four inks, which will typically be black and three other colors, but it is obvious that a greater number of different inks may be used if desired without departing from the scope of the present invention. Upon the top of upper block 1 there are mounted four ink nozzles 5, 6, 7 and 8 (see Fig. 9), one of which is shown at 6 in Fig. 6 and another indicated diagrammatically at 5 in the representation of Fig. 7.,

Each of the nozzles is provided with an orifice having a diameter of the order of 0.004 inch, and the nozzles are all directed into the upwardly moving air stream emitted by the opening 31. The nozzles may be arranged to be substantially transverse to the air stream as shown in Figs. 6 and 7, or they may be formed to discharge ink in a direction approaching parallelism with the air stream as shown in Figs. 9 and 10.

Supply of ink to a nozzle is effected through its as sociated ink conduit as shown at 10 in Fig. 7, which is adapted to communicate with an ink reservoir chamber in the member 17.

The ink reservoir chambers just referred to are circumferentially arranged in pairs and vertically disposed in the member 17 as shown at 18 and 19. In Fig. 7, the vertical ink reservoir chamber 19 is shown in communication at its upper end with the conduit leading to nozzle 5 and at its lower end is in electrical contact with electrode 32 connected to input conductor 9. Since the lower block 2 and the member 17 are insulators and upper block 1 is a conductor, an input electric current can be caused to flow through a circuit including conductor 9, electrode 32, the ink in reservoir chamber 19 and the upper block 1. The ink itself is of course conductive as previously pointed out, and the passage of current therethrough heats the ink and expands it in accordance with well known principles. As in the case of the embodiment of the invention first shown and described, the heat transfer to the walls of chamber 19 is small and may be made to be negligible for a desired period of operation.

Means are provided for replenishing the ink at periodic intervals. Such means include port 20 adapted to be connected to a source of ink or an ink pump, port 20 communicating with conduit 21 having branches 22 and 23 and vertical ducts 24 and 25 whose lower open ends abut the upper surface of the member 17. In the position shown in Fig. 7, port 20 is in communication with reservoir 18 of the member 17 by conduits 21, 23 and 25. The lower block 2 of the reproducing head is provided with conduits or discharge tubes 26 and 27 joining at ink discharge port 29.

Discharge port 29 is in communication with an ink storage reservoir or sump. The ink is pumped from this reservoir through a plug of cotton or glass wool in order to remove any drops of oil which may be present and is then passed through a chamber for the separation of any possible air bubbles. Thus the ink flows into port 20, out of port 29, and back into the storage reservoir. Oil which has been flushed from the ink reservoirs 18 and 19 accumulates in the storage reservoir either above or below the ink according to its density. Periodically the oil is drained from the storage reservoir and the ink is replenished. The ink pump may be a small diaphragm pump such as an automobile gasoline pump.

The circular member 17 is partially rotated at suitable intervals in successive opposite directions so as to periodically introduce a bore filled with fresh ink into the ink 7 conduit leading to a" nozzle. In Fig. 7, the bore 18 is shown being flushed whereas bore 19 has been introduced into the inkconduit. When the circular member 17 is' partially rotated it will be rotated so as to move the bore 19 into alignment with the flushing bore 24, the refilled and recharged bore 18 being then placed in alignment with the ink conduit 10. Preferably the bores 18' and 19' are spaced a distance equal to their diameter along the arc of their movement so that the change from bore 18 to 19 and vice versa is almost instantaneous.

It is to be understood that although the conduits associated with nozzle 5 have been described in detail, similar' arrangements of conduits, chambers, electrodes and input electric conductors are associated with each of the other nozzles.

Fig. 8 discloses means for supplying a lubricating oil to the periphery of the intermittently reciprocated circular member 17, a suitable sealing ring 28 (see Fig. 6) being positioned around the member 17 to prevent oil leakage between the blocks 1 and 2. Such means include an oil inlet port 33 and a conduit 34 communicating with the annular chamber surrounding member 17 and within sealing ring 23. The pressure of the oil in the sealed chamber thus formed is maintained at a value greater than the maximum pressure in any of the ink reservoirs. By this means the inks are prevented from leaking out along the sliding surfaces of member 17. Instead, the lubricating oil leaks into the ink reservoirs along the sliding surfaces, but due to the high viscosity of the oil the leakage is negligible, and, as previously set forth, the oil is strained or otherwise removed from the inks while the inks are passed through their respective sumps.

It will now be seen that the modulated alternating current signal produced by the circuit of Fig. 5 constitutes the input signal to be applied to conductor 9 of Fig. 7

and'of course other input signals corresponding to other colors may be fed to their corresponding conductors in the lower block 2 of the reproducing head.

Many modifications and changes may be made from the specific forms of the invention herein shown and described without departing from the spirit of the invention, and all such modifications and changes are intended to'be embraced within the scope of the appended claims.

I claim:

1. A reproducing head adapted for use in the reproduction of pictorial illustration comprising: an air conduit; means for supplying air under pressure to said conduit; a nozzle having an opening directed into the air stream from said air conduit; a movable member within said head provided with a plurality of ink chambers and adapted, by its movement, to successively insert each of said-ink chambers, one at a time, into communication with said nozzle; means for heating ink in the chamber in communication with said nozzle at a rate instantaneously correlated to the amplitude of an input electric signal; means for moving said member; and means for flushing and replenishing the ink in an ink chamber not in communication with the nozzle.

2. A reproducing head adapted for use in the reproduction of pictorial illustrations comprising: an air conduit; means for supplying air under pressure to said conduit; a nozzle having an opening directed into the air stream from said air conduit; means forming ink chambers in said head; means for successively inserting one of said chambers into communication with said nozzle, said inserted chamber being otherwise closed; means for passing a controllable electric current through ink in said inserted chamber; and means for flushing and replenishing ink in another of said chambers not in communication with said nozzle.

3. A reproducing head adapted for use in the reproduction of pictorial illustrations comprising: an air conduit; means for supplying air under pressure to said conduit; a nozzle having an opening directed into the air stream from said air conduit; means forming ink chambers in said head; means for successively inserting one of said chambers into communication with said nozzle, said inserted chamber being otherwise closed; means for heating ink in said inserted chamber at a rate instantaneously correlated to the amplitude of an input electric signal; and means for flushing and replenishing ink in another of said chambers not in communication with said nozzle.

References Cited in the file of this patent UNITED STATES PATENTS 1,709,926 Weaver Apr. 23, 1929 1,957,646 Hinton May 8, 1934 2,060,039 Clapp Nov. 10, 1936 2,100,204 Shore Nov. 23, 1937 2,186,718 Ferguson Jan. 9, 1940 2,262,964 Reilly et al. Nov. 18, 1941 2,278,940 Murphy Apr. 7, 1942 2,526,405 Peeps Oct. 17, 1950

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