DE2428732A1 - COLOR REPRODUCTION PROCESS AND DEVICE FOR CARRYING OUT THE PROCESS - Google Patents

Description

PATENT AGENCY OFFICE TlEDTKE - BüHLING - KlNNE 2428732

TEL. (0811) 539653-58 TELEX: 524845 llpat CABLE ADDRESS: Germaniapatent Munich

8000 Munich 2

Bavarlaring 4

P.O. Box 20 2403 »June 14, 1974

B 6087

Canon Kabushiki Kaisha Tokyo / Japan

Color reproduction method and apparatus for carrying out

of the procedure

The invention relates to color reproduction techniques in electrophotography, using multicolor developing agents, and more particularly to a color reproduction method and apparatus for its implementation, in which the developing agents are used very effectively and sparingly.

Various electrophotographic methods such as the Carlson method and the NP method in which an electrostatic charge image is formed on a photosensitive body, the TESI method in which

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the electrostatic charge image first on recording paper (or an image transfer sheet), and then transfer the recording paper to which the Charge image has been transferred, developed, or a screen process etc. This electrophotographic As is well known, processes can also be grouped according to two systems, namely according to the direct system in which the reproduced image as it is fixed on the photosensitive body and the transmission system, in which the image formed on the photosensitive body is transferred to a transmission organ, whereupon the transferred image is frozen. More precisely, the image is in the case of a colored original image after the direct. th system by repeating an electrical charge 3 or 4 times, an exposure through a color separation filter, development and fixing while repeating the color image in the transfer system cleaning of the photosensitive plate, electrical charging, exposure through color separation filters, of developing and transmitting is obtained.

In the devices for carrying out the above-mentioned method steps one encounters the problem that the color developing agents used for dye reproduction used tend to be in the developing section

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and the cleaning section of the device. So far it has been quite natural that such a developing agent mixture was disposed of as waste, since it is able to change the hue of the colored the reproduced image. However, the accumulation of such waste inevitably exercises one adversely affect the maintenance of the reproducing apparatus and the environment into which this waste is discharged will.

In view of this problem peculiar to the conventional devices, it is an object of the invention therein, an improved color reproduction process and to provide an apparatus for carrying out the same in which the remaining developing agents are exposed to the light "" sensitive bodies can be recovered and regenerated for reuse without being disposed of as waste. In addition, the color reproduction apparatus of the present invention should be equipped with a control mechanism that can be used without affecting the quality of the images to be reproduced is impaired simultaneously with the reuse of the regenerated developing agent will. The color reproduction apparatus of the present invention is intended also enable masking reproductions and monochromatic reproductions, and a mechanism for effectively distributing an amount of developing agent, so that the reproducing apparatus is very

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works economically.

The invention is a color reproduction method provided with the use of multicolored developing agents, that by recovering the multicolor developing agents used for image development and during the development process have been mixed together, and by regenerating that recovered as overflow Developing agent for reuse is excellent as the black developing agent.

The device according to the invention for color reproduction of a color original, in which an electrostatic Charge image formed on an electrostatic charge image support member with multicolor development development media is developed includes a plurality of development devices, at least one of which is black Developing agent contains means for recovering the developing agent used during the image developing process have been mixed, and a device for transferring the mixed multicolored Development funds from the recovery facility to

the developing device containing the black developing agent.

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The transmission device for the mixed
multicolor developing agent advantageously has one
Device for determining the transfer amount of mixed developing agent and a device for controlling the transfer process.

The developing agent recovery device
the color reproducing device according to the invention has, in particular, a device for storing the recovered undeveloping agent and a device for determining the color phase of the mixed multicolor developing agent in the storage device.

The developing agent storage device of the present invention The color reproducing device also advantageously includes a device for supplying and mixing in one additional amount of black developing agent depending on the output of the detector Determination of the color phase.

The invention is explained below on the basis of the description of exemplary embodiments with reference to FIG
Drawing explained in more detail.

Fig. 1 shows a vertical section of the color reproduction device according to the invention in Sche-4U9ÖÖ1 / 1169

matic representation;

Pig. 2 is a perspective view of FIG

Color developing agent recovery means attached to the cleaning section the reproduction apparatus is provided;

Fig. 3 is a block diagram for explaining an embodiment of the recovery the mixed developing agent for reuse;

Fig. 4 is a circuit diagram of an embodiment of the means for determining the concentration the primary color developing agent in the black developing agent acting as Result of the development process mixed up have been.

Fig. 1 shows the construction of a reproduction apparatus employing wet development and a photosensitive one NP-type plate as a photosensitive member and multi-color reproduction or reproduction a color original can be obtained. The color master 2, which lies on a transparent support 1, is v / ird from a Light source 3 irradiated. The light emitted by the light source 3 passes through mirrors 4 and 5 through an objective and passes through a color separation filter 7a, which is of a

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Turret 7 is carried for the color separation filter, which is changed depending on the respective color breakdown; then the light is reflected by means of mirrors 8 and 9 by an AC charger 12 to a photosensitive Drum 10 is reflected.

In the above optical system, the light source 3 and the mirrors 4 and 5 become synchronous with the Rotation of the photosensitive drum 10 in their

Positions 3 ¹ , 4 ¹ and 5 ¹ moved. The photosensitive drum 10 is operated by a cleaning blade

Jl

2 4 cleaned, by means of a primary charger · 11 elektrlsceh charged and discharged by means of the AC charger 12 at the same time as the image exposure.

The photosensitive drum 12 exposed in this way then becomes a total exposure of its entire Surface exposed by means of a further light source 13 and through one of the development containers 14, 15, and 17 developed. Each of these developing tanks gets a specific developing agent from one of the developing tanks 14 ', 15', 16 * and 17 '. The development tanks are constructed to be synchronized with the movement of each of the respective color decomposing means 7a, 7b, 7c and 7d in the filter turret 7 are pushed into the development position and back. The one at the

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photosensitive drum 10 adhering to an excessive amount of developing agent is squeezed off with the help of an electric charger provided for squeezing or stripping. On the other hand, a transfer paper 19 is set in motion by means of a roller 20 and placed on an image transfer streammer 21 held adjacent to the photosensitive drum 10. The developed on the photosensitive drum 10 Image is therefore on the tangential line of contact between the two drums onto the transfer paper held on the drum 21.

In the event / that a dye reproduction is created should, the aforementioned method steps are repeated three or four times, whereupon the transfer paper 19 detached from the transfer drum 21 and by means of a Conveyor belt 22 is carried to an image fuser 23 where the transferred image is fused to complete the copy will. The transfer drum 21 is otherwise by a movable cleaning blade 25 cleaned so that the back of the subsequent transfer paper is not through any foreign matter left on the drum may be stained.

On the other hand, if a monochromatic copy is to be obtained, exposure is carried out through the filter 7d, while the exposed image on the photosensitive

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Drum is developed by the developing tank 17. In this case, it goes without saying that the transfer paper already detached after the completion of a transfer process from the transfer drum 21, in the Fixing device is fixed and issued.

In the course of the aforementioned developing and cleaning operations, however, occurs on the cleaning blade 24 of the reproduction apparatus inevitably mixing or mixing of the developing agents takes place. Such a thing Mixing also occurs near development tanks 14, 15, 16 and 17 as the development agents are attached to them Places tend to drip down. Further, the developing agents are subject to the use of the electric charger stripped from the surface of the photosensitive drum IO be a mixture of colors. The mixed or blended developing agents are made by various kinds recovered from resources. For example, on each of the development containers, the electric charger for stripping, the cleaning blade etc. a collecting vessel is provided so that the dripping liquid developer is collected therein and with the help of a pipe to the developing tank for black toner or the storage tanks for the appropriate developing agent can be supplied. As As explained below, it is of course possible to do this

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to conduct collected developing agent into the desired container only when the color phase and concentration of the color developing agent are set appropriately.

A diluent for the developing agent can be supplied to the cleaning blade 2 4 through a liquid supply pipe 26 flow so as to prevent the recovered developing agent from adhering to the cleaning blade adheres so that the developer is effectively recovered together with the diluent. You can also use the of the cleaning blade 25 with a colorless diluent for the developing agent attached thereto Let the cleaning blade 25 flow away and recover it, so that the one held on the transfer drum Transfer paper is not stained. For this liquid recovery, the details are given in the description British Patent 1,326,786 (DAS 2 047 130), for example, explains the construction of the photosensitive body particularly suitable.

It is also possible that the recovered liquid is first collected in a collecting container and then with a concentrated black developing liquid adjusted to a certain concentration for reuse or that the recovered liquid is poured directly into a container for the black developing agent.

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and adding the concentrated black developing agent depending on the necessity is used again for this purpose.

Fig. 3 explains an embodiment of a control mechanism for adjusting the concentration of the Developing agent. According to this control mechanism, the recovered developing agent is first collected in a collecting tank 31 and then through a valve 33 in a mixing tank 35 out. The mixing tank 35 is provided with an end detector 351 of the control circuit to the Determine and control the color phase, and with an agitator 352 to increase the concentration of the developing agent equalize.

Fig. 4 shows an embodiment of a mechanism for detecting the color phase and for controlling in which the end detector 351 with a plurality of photocells CdSl, CdS2 and CdS3 is provided, which have a red, a blue and a green filter fl, f2 and f3 and which have a single white light source LP1 in common. With this circuit configuration of the end detector 351 the valve 33 or the valve 34 according to FIG. 3 is opened or depending on the output signal of this detector closed.

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If the output of each photocell is essentially the same, in the color phase control, for example, valve 33 is opened, while if any of the photocells provides a different output, valve 34 is opened. Otherwise, valve 33 is constantly open and an upper value is set for the strength of each hue, and if any of the detent elements exceeds the upper limit of the set value, valve 34 is opened so that the desired result of color phasing is obtained. The embodiment shown in FIG. 4 corresponds to this design, in which each set value can be set as desired by regulating one of the input terminal potentials of each operational amplifier by means of each variable resistor VR ₁ , VR 2 or VR _3.

In this way, the developing agent present in the mixing tank 35 shown in FIG. 3 may always be black or on a hue recognized to be substantially black.

On the other hand, the opening and closing of one between the mixing tank 35 and a developing unit 38 becomes provided valve 37 is controlled by an output of a further end detector 381 in the developing unit 38 is provided, whereby the concentration of the development

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can be kept at a constant level by means of.

Although the above description is based on a liquid development, it is of course possible that achieves almost the same construction, function and effect in the case of using a dry developer will. In this case, the recovery blades, etc. may also be constructed as shown in the drawing is, although the design of the recovery and conveying devices for the developing agent included in Pui ^ rform is available »special attention should be paid should. As shown in Fig. 2, a screw 28, the total length of which corresponds to the drum width, is just in front of the Cleaning blade 24 is arranged and transports the powdery developing agent that is stripped from the blade has been, in the transverse direction. The powder developer transported sideways in this way is then placed in a chute collected, through which he is promoted to the development unit. The caught Balverentwiekler can on the other hand can also be fed into the development unit via a pipe with the aid of a suction fan. Finally, a funnel-shaped Container 291 for storing a certain amount of the transported developing agent at the end of the chute or the pipe 29 may be provided with a valve opened and closed by the operation of a solenoid SDL is when a predetermined amount of the transported powder

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developer with the help of a lamp LP and a photocell CdS is detected.

For a better understanding of the invention, as far as it has been described above, the following is used The result of an experiment shown with the critical amount of each of the primary color developing agents experimentally which is allowed to be present in the black developing agent has been determined.

Color developing agents for blue, red and yellow were prepared, and each of these developing agents became mixed with black developing agent in a certain amount for each of the cases below. Afterward a monochromatic reproduction was carried out using the reproduction device described above, to find out the critical admixture amount at which the hue of the reproduced image is no more than really black is recognized. The results are as follows:

colored developing agent, critical mixing amount with which was mixed with black developing agent medium

blue Red (*) 20% Red yellow {*) 1O% yellow blue (*) 2O% blue + red + yellow (*) 30% red + 409881/1 169 20% yellow + 25% blue + 65%

(*) Each developing agent in an equivalent amount.

As described in detail above, the reproduction apparatus of the present invention is capable of the mixed To regenerate developer so that there is no fear of wasted developer after development and any loss of developing agent can be reduced, making it very economical Maintenance and operation of the reproduction device contributes.

Incidentally, in a reproduction apparatus for office use, both multicolor reproduction as well as monochromatic reproduction, the mixed developing agent can be used as it is, without requiring any complicated control of the color phase when in monochromatic reproduction the color tone of the copies produced does not matter.

Further, when the mixed developing agent is mixed with black developing agent for reuse a good shade of black can easily be obtained if a locking and control element of known type is used is, therefore, the 'construction of the operable device can be realized very effectively.

4US881 / 1169.

The invention thus provides a color reproduction apparatus which uses multicolor developing agents, the developing agents which change in the course of the
Development have mixed, can be reused as black developing agent, for whatever purpose the device with
a plurality of developing devices, a mixed developing agent recovery unit, and one
Conveyor unit is equipped for the mixed developing agent to transport them from the recovery unit to the developing unit.

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Claims (7)

Claims (l. <color reproduction process, the multicolor developing agent used, characterized in that those multicolor developing agents, which are in the course of the development process, recovered and reused as black developing agent be regenerated. 2. The method according to claim 1, characterized in that at least three primary color developing agents are used as multicolor developing agents and a black developing agent and the amount of the three primary color developing agents which may be mixed with the black developing agent does not exceed 65% by weight. 3. A method for color reproduction of a colored original image using at least three primary color developing agents and a black developing agent characterized by the following steps: (a) Recovering and storing - the multicolor developing agents, that were mixed together during the image development process; (b) determining the color phase of the mixed multicolor developing agent; and A 0 9 8 8 1/1 1 6 9 (c) admixing an additional amount of the black developing agent to regenerate the mixed ones used Multi-color developing agent as a black developing agent for repeated use depending on from the result of the determination of the color phase. 4. Device for dye reproduction of a colored Original image in which an electrostatic charge image formed on a charge image carrier member with multicolor developing agents is developed, characterized by a plurality of developing devices (14, 15, 16, 17), at least one of which (17) contains black developing agent, by means (24, 25, 27) for recovery of the multicolor developing agents used during the image developing process are mixed together, and by means for transferring the mixed together Multicolor developing agent from the recovery device to the one developing device containing black developing agent. 5. color reproduction device according to claim 4, characterized in that the means for transferring the multicolor developing agents mixed together means for detecting the amount of transfer of the mixed developing agents; and means for 4 09 88 1/1169 Control of the transfer process contains. 6. color reproduction device according to claim 4, characterized in that the means for recovering the mixed developing agents comprises means (35) to store the recovered developing agents and means (351) for determining the color phase of each other mixed multicolor developing agent in the storage means. 7. color reproduction device according to claim 6, characterized in that the means (35) for storage the developing means a device (32, 33, 34, 36) for supplying and blending an additional amount of the black developing agent depending on one Signal from the color phase detection device (351). 433381/1169 Blank page