JP3476998B2 - Wet electrophotographic compact color printer and color image forming method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus and an image forming method, and more particularly to a small (desktop type) color laser printer and an image forming method suitable therefor.

[0002]

2. Description of the Related Art Multicolor images (color images) by electrophotography
The formation was already successful in the mid-1970s, but it was not realized. This technique was by wet electrophotography. After that, in the 1980s, color image formation was attempted using the dry digital PPC technology established up to that point, and as a result of being applied to a copying machine, it is now seeing prosperity.

As the next stage, small size (desktop type)
The application to printers has been very recently undertaken, and the result has been revealed as a sale by several leading companies from last year to this year. However, the problems of dry electrophotography have already been pointed out since the time of color copying, which has caused many companies to hesitate to adopt printers.

The problem is as follows. (1) Insufficient resolution. 400 dpi, 600 for latent images
Although the resolution is high, 400 dpi is Max in the visible image. (2) Solid uniformity is poor and sufficient photographic reproduction cannot be performed. In the digital copying technique, dots are represented by binary values, and the solid uniformity can be modified. However, when it becomes 400 dpi or more, the dots become closer to each other when viewed from the developing system as the height becomes higher, and the dots become continuous and equivalent to analog. That is, the badness at the time of analog comes out again. (3) Gradation reproduction is insufficient. (Similar to the above, it becomes closer to analog at higher resolution.) (4) The device becomes larger. (5) Maintenance-free property is low. (It can't be said that it will be operated for several years with no maintenance after installation at the user's site.) (6) The device is complicated. On the other hand, as a wet electrostatic color printer, Japanese Patent Laid-Open No. 3-1
Although there are those disclosed in Japanese Patent Publication No. 97987, these are large-sized printers, and none have been put to practical use as small-sized wet color printers.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to achieve a maintenance-free property in which an electrostatic image can be accurately color-developed and transferred to a high-quality color image by a small and relatively uncomplicated mechanism. An object is to realize a high color printer and to provide a color image forming method therefor.

[0006]

The object of the present invention is as follows. (1) "A charging device, an exposing device, a developing device, and a transferring device are provided around a drum-shaped photoreceptor having a photosensitive layer on a conductive substrate. An electrophotographic color printer including a fixing device, a discharging device, a cleaning device, and a paper feeding device and a paper discharging device, wherein the developing device is for developing liquids of black, yellow, magenta, and cyan. The respective developing units for are arranged in parallel, and the developing units are mainly the developer tank,
It comprises a developing solution, a developing roller, a developing / non-developing control section, and a developing solution drawing-up thickness controlling section, and the developing-non-developing controlling section also serves as the developing solution drawing-up thickness controlling section and the developing roller.
When the developer and the photoconductor are placed in contact with each other,
Is pressed against the developing roller and sucked to the contact part.
It is possible to completely prevent pumping up so that there is no developing solution
And further has a solvent recovery device if necessary,
Small electrophotographic color printer using wet toner ",
(2) "The means for turning ON / OFF the carrying of the developing solution on the developing roller in the developing device is performed by urging and releasing the doctor blade made of resin against the developing roller. (1) The small electrophotographic color printer described in (1) above, and (3) "wherein the exposure device is an optical system of laser scanning, LED irradiation, plasma display irradiation, EL irradiation, or a combination of a light source and a liquid crystal shutter. (1) The small electrophotographic color printer according to (1) or (2) above, (4) "wherein the charging device and the transfer device are composed of corona discharge or voltage application roller charging. (1) The small electrophotographic color printer described in any one of (1) to (3), (5) "Use collected by the cleaning device. 5. The device according to any one of (1) to (4) above, which is equipped with a device for separating toner particles and carrier liquid from a developer, and has means for recycling only the carrier liquid to a developer tank. , (6) "Repeat transfer of four colors and transfer of the transfer material after being fixed in or after the transfer material to the paper discharge path is controlled by moving the claw. (7) The small electrophotographic color printer according to any one of (1) to (5) above, characterized in that the fixing device is an ordinary heat roller or the back side of the transfer material (opposite the toner adhering surface). Any one of the above (1) to (6), characterized in that it is heated directly or indirectly from the side) by a heater.
Compact electrophotographic color printer described in ". In addition, (8) "a toner image is formed by subjecting the photosensitive layer of a drum-shaped photoreceptor having a photosensitive layer on a conductive substrate to each of black, yellow, magenta, and cyan for charging, exposure, and development. The toner image is transferred to a blanket adjacent to the photoconductor by pressing and / or heating and / or applying an electric field, and the toner image formed on the blanket is pressed and / or heated from the blanket to a transfer material. And / or repeating the step of transferring by applying an electric field four times,
An electrophotographic color image forming method including a step of fixing a toner image on the transfer material, if necessary, wherein the developing treatment step is carried out in developing sections of the four colors arranged in parallel,
Respective developing unit is a developer tank, a developer, a developing roller, a developing - non developing control unit consists developer pumping thickness control unit to the developing roller, and developing - non-developed control unit, on said developer Kumi
Also functions as a thickness control unit, and further, the developing roller and the photosensitive member
When installed in contact, when not developing, the developing roller
No developer is sucked into the contact area due to pressure contact with
An electrophotographic color image forming method characterized by being able to completely prevent pumping up to such an extent , (9) "First
The electrophotography according to the above (8), characterized in that an image is formed in color, the toner image is transferred to a transfer material by applying an electric field, this is repeated up to the fourth color, and then a fixing process is carried out if necessary. Color image forming method ", (10)" Toner image obtained by subjecting the photosensitive layer of a drum-shaped photoreceptor having a photosensitive layer on a conductive substrate to each of black, yellow, magenta, and cyan for charging, exposure, and development. The toner image is formed on an endless belt made of an insulating resin and is transferred to the paper conveyed without mechanical clamp by applying a transfer electric field from the back side of the belt by a corona charging or voltage application roller to transfer the image. The method is an electrophotographic color image forming method including a step of performing fixing if necessary, repeating the step 4 times, separating the transfer paper from the endless belt, and performing fixing if necessary, wherein the development processing step comprises Each of the four colors Of the developing units arranged side by side, each developing unit comprising a developing tank, a developing solution, a developing roller, a developing-non-developing control section, a developing solution pumping thickness control section for the developing roller, and the developing section. The non-development controller draws up the developer.
Also serves as a thickness control unit, and also contacts the developing roller and the photoconductor.
If the product is not touching when it is installed in touch,
By the pressure contact, the developer is attracted to the contact portion is none
(11) "Electrophotographic color image forming method characterized by being able to completely prevent scooping up ", (11) "Transfer of the transfer material by the endless belt for the transfer is performed before the transfer material is aligned with the paper. Charging of the transfer material by a corona discharger facing a grounded guide plate provided in the conveying process, and electrostatic attraction between the charge and the belt and / or the grounded drive pulley. The electrophotographic color image forming method according to (10) above,
(12) “The transfer of the transfer material on the transfer endless belt is performed by charging the transfer material by a corona discharger provided facing a pulley that is grounded at a position where the transfer material is aligned with the belt. The method for forming an electrophotographic color image according to (10) or (11) above, characterized in (1)
3) “A toner image is formed by performing a charging, exposing, and developing process on a photosensitive layer on a drum-shaped photosensitive body having a photosensitive layer on a conductive substrate for each color of black, yellow, magenta, and cyan to form a transfer material. Repeat the process of transporting the toner image on the photoconductor to the transfer material for each color to the transfer material, fixing the toner image on the transfer material as necessary, and fixing the toner image if necessary. An electrophotographic color image forming method including a step of printing on paper, wherein the developing process is carried out in developing units arranged in parallel for each of the four colors, each developing unit comprising a developer tank, a developer, a developing roller, The development-non-development control unit and the developer scooping thickness control unit are included .
Also serves as an image liquid pumping thickness control unit,
When installing in contact with the photoconductor, when not developing,
Due to the pressure contact with the developing roller, the current attracted to the contact portion is detected.
It can completely prevent pumping up to the point where there is no image liquid.
That it is achieved by an electrophotographic color image forming method ", wherein.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to Examples. FIG. 1 is a cross-sectional view of an example of a developing device of a small wet type color printer which is the basis of the present invention. (4a-B
k), (4a-C), (4a-M), and (4a-Y) developing units having four color developers are arranged in parallel and arranged with respect to the photoconductor (1). This figure shows the rightmost color development unit (4
a-Bk) is shown being developed, and the developing parts for the other three colors are in a non-developing state.

The diameter of the photoreceptor (1) in this example is usually 3
0 mmφ to 200 mmφ, therefore, the width of the developing portion for each color is 20 to 100 mm, and the total width of four colors is 80 to 40 mm.
It is 0 mm. One developing unit will be described with reference to FIG.

FIG. 2A shows a non-developed state and FIG. 2B shows a developed state. In the development-non-development, a movable rubber blade (4d) is rotationally moved around a support shaft (4e) so as to be pressed against the development roller (4c) (non-development) or released ( Development). The thickness (4f) of the drawn up developer layer is the blade (4d)
Gap between the developing roller (4c) and the photoconductor (1). Each of the developing sections has a developer tank (4a) and a developer solution (4a).
b), the developing roller (4c), the rubber blade (4d), and the blade supporting portion (4e), which are simplified and can be accommodated within a maximum width of 100 mmφ. If necessary, other parts may be added. The rotation direction of the photoconductor (1) is the direction of the arrow in the figure.
The smaller the gap with the photoconductor (1), the higher the resolution of the image, but it is set to 0 to 1.0 mm. (Contact also acceptable.) The developing roller (4c) is mainly a bias voltage consists metallic layer is applied (omitted in the drawing). The depth of the tank (4a) is 20-
It is 100 mm. The contactor tank, inlet, carrier liquid (solvent) tank, and inlet are omitted in the figure.

The contact toner is replenished as needed.
In addition, the development / non-development control by the blade (4d) is 1
It's an example, not something to be bound to.

FIG. 3 shows an example of the construction of a wet small color printer of the present invention using the developing device of FIG. PC: The photoconductor (1) has a photoconductor layer (organic or inorganic) provided on a grounded conductive substrate. Charging and transfer are performed by a corona or a roller to which a voltage is applied. The charging device in this example shows a corona. The PC (1) is rotated in the direction of the arrow in the figure. The exposure by the exposure device (3) is laser scanning, L
It is performed by an optical system of any one of an ED light source and a lens, a plasma light source and a lens, an EL light source and a lens, and a light source and a liquid crystal shutter. It may also be an analog optical image. Laser light is used in this example. The developing unit has the structure as described above. After the development, the blanket (5) is pressed and rotated at a constant speed with the photoconductor (1). Its structure mainly comprises a gold layer core and a rubber layer. In this device example, the blanket (5) is heated by the heater (6) and the surface temperature is 50 to 200 ° C. Since carrier liquid is present in the developed developer, either (i) breaking of the toner liquid from the surface tension zone of the carrier liquid or (ii) carrier liquid-carrier liquid division is required for transfer. Therefore, the transfer is difficult as compared with the dry method. The transfer function is insufficient by electrostatic transfer with a corona or roller. However, in this apparatus example, the blanket (5) is used, and the transfer rate is high because transfer is performed by heating (not heating) and the pressing effect. A bias voltage may be applied to the gold layer core of the blanket (5) to utilize the electrostatic transfer effect together.

The transfer material (21), which may be, for example, paper, is fed from the tray (22) by the paper feeding corona and guided to the charging portion (12) of the conveyor belt (9b) via the guide plate (9c). The conveyor belt (9b) is an endless belt formed of resin, rubber or the like, and includes a pair of pulleys (9b).
It is stretched by d) and rotated in the direction of the arrow in the figure. The paper guided to the charging section (12) by the conveyor belt (9b) drops the corona toward the grounded one by the conductive plate (19) provided under the belt (9b) (the charging corona ( The belt is charged by 12), sucked together and sent to the blanket transfer station. The metastases, mainly by the pressing roller 2 transfer device comprising a metallic layer (13), a belt, since the paper is pressed against the blanket (5), warming effect of the blanket (5), the pressing roller The pressing effect of (13), and in this device example, since the pressing roller (13) is applied with the bias voltage, the developing toner (4b) is transferred from the blanket (5) to the paper (21) by the three parties of the electrostatic effect. ) Is transferred to. Compared with the blanket (5), the paper (21) has a rough surface and is porous, so that the toner is easily transferred. When the first to fourth colors are developed and transferred, the separation claw (18) of the conveyor belt (9b)
Is dissociated. After the above developing, transferring and transferring steps are repeated four times, the separation claw (18) is urged to separate the paper (21) from the conveyor belt (9b), and if necessary, it is fixed by the fixing device (10) and discharged. To be paper. Fixing device (10)
A heat roller, a heating plate, an atmosphere fixing, or the like is used as this. If necessary, a static eliminator for neutralizing the charge on the conveyor belt (9b) may be provided.

As the static elimination device (7) around the PC (1), light irradiation and / or corona static elimination are used. A corona is provided in this example device. PC after transfer (1)
The developer remaining on the upper part enters the cleaning section (8) and is wiped off by a rubber blade (8a). To prevent backflow, the seal plate (8b) made of a thin resin plate is used for PC
It is in contact with (1). The stored cleaning developer may be sent to a pipe (not shown) by the feed blade (8c), the toner particles may be removed by the toner separating device, and the remaining carrier liquid may be recycled to the developing unit if necessary. In this case, the carrier liquid is consumed less, and it is almost unnecessary to replenish it. Isolated captured toner housed in the toner Box not shown Re collected et Figure is (automatically) recovered by or serviceman is discarded by the user.

The disadvantage of wet electrophotography is that solvent gas is generated. The occurrence locations are the developing section, the fixing section, and the cleaning section. If necessary, a recovery device may be provided. In this example, solvent recovery ports (14) and (15) are provided and sucked by a fan. Almost all of the solvent is vaporized by fixing, so almost no solvent is discharged outside the machine through the fixing section. Not even on copy paper. Fixing is also important as solvent removal. The sucked solvent gas is sent to a recovery device (not shown). There are two types of recovery devices: a liquefaction device and an adsorption device. In the type of collecting, the collected intake air is concentrated and pressurized, and then cooled to be liquefied. The liquefied solvent (carrier liquid) has a high purity and does not cause any problem even when returned to the developing section.

The above is the operation and operation of the individual apparatus of this example. The overall movement is as follows. Photoconductor (1)
Is charged by the charging device (2), an optical image corresponding to the first color is irradiated on the PC (1) by the exposure device (3), a latent image is formed, and a first color developer, for example, a developer is formed in the developing section. After being developed by (4a-Bk), it is transferred to the blanket (5) and further transferred to the paper (21).

At this time, the separating claw (18) is disengaged from the conveyor belt (9b), and the paper (2) together with the belt (9b) is separated.
1) is conveyed again. After that, static elimination by the static elimination device (7) and cleaning by the cleaning device (8) are performed. Next, after the same process from charging to development for the second color is carried out, the PC (1) and the paper (21) are sent to the transfer section again without any positional deviation and transferred to the blanket (5). First
The color toner is transferred to the paper by heat, pressure, and electric field at the transfer portion, and is anchored in the porous paper (21). Therefore, the first color toner is blanket (5).
It never transposes back to. Similarly, the second color toner is also anchored to the paper (1) by superposing it on the first color. Since the transfer rate from the blanket (5) to the paper (1) is almost 100%, the images do not overlap even if the blanket (5) is not cleaned. After that, the charge is removed and cleaned. Repeat this for 4 colors. When the transfer of the four colors is completed, the separation claw (18) of the conveyor belt (9b) is actuated, the paper (1) is separated from the belt (9b), and the fixed paper is discharged. All the developing rollers (4c-Bk) (4c- around the drum (1)
C) (4c-M) and (4c-Y) are put in a non-developed state, and the PC (1) is completely cleaned and prepared for the next print.

FIG. 4 shows another example of the apparatus. Exposure, transfer,
The configuration is the same as that of FIG. 3 except for the fixing unit. The fixing device (10) is provided in the transfer section, and there is no fixing section after the transfer of all toner images. As for the transfer section, the conveyor belt is not provided. Further, the image on the photoconductor (1) is directly transferred as a mirror image to the transfer material, rather than being transferred once to an intermediate transfer body such as a blanket and then transferred to the transfer material again. It is a mirror image of the image of the original, and therefore the number of reflecting mirrors in the photosensitive device is an odd number. The switching between the repeated transfer and the discharge is performed by the branch claw (18). When the transfer is repeated four times, the lower part is lowered and the upper part is discharged. Paper fed from the paper feed tray (22) (2
Transfer material after the transfer of the first color developer separation claw 1) (2
It is separated from the PC by 3 ), and the path is bent by the suction means (15) which also serves as the solvent recovery means to enter the transportation path. Here, it is fixed by the heater (10) from the back side of the paper (21) and is sent to the transfer section again. Paper transport is all 4
It is carried out by individual feeding rollers (9 g). If four colors are transferred, the paper is ejected. In this example, solvent recovery means (14), (15) and (17) are provided at three locations.

FIG. 5 shows another device example. Figure 3 except for transcription
The device is the same as that of. The paper (21) is fed by the paper feed roller of the paper feed unit (22), delivered to the feed roller (9), and fed along the guide plate (9c). Guide plate (9
c) it is grounded made metallic, corona charger (12) is disposed toward thereto. Paper fed (21)
Are now charged and electrostatically stick to the conveyor belt (20). 3 is the same as in the apparatus example of FIG. 3 except that the toner image on the photoconductor (1) is directly transferred onto the paper as a mirror image.

The paper (21) is sent to the transfer portion by the belt (20) and charged together with the conveyor belt (20), and the developing toner is transferred onto the paper. The conveyor belt (20) is a belt similar to that shown in FIG. The paper (21) is conveyed by the belt (20) as it is, and the paper (21) is conveyed by the belt (20).
The fixing device (10) arranged on the back side of the sheet heat-fixes from the back side. However, the fixing at this time is provisional to the extent that reverse transfer is not performed, and the heater surface temperature is as low as 50 to 100 ° C. The peeling (separating) claw (18) is separated from the belt (20), and thus is sent to the hypothetical attachment part. Do this 4 times (color)
After the repetition, the separation claw (18) is urged to separate the paper (21), and the paper is surely fixed by the fixing device (11) and discharged.

A conveyor belt satisfying these requirements is an endless belt made of an insulating resin film. The application of the transfer electric field through the belt is achieved by directly performing corona discharge from the outside. That is,
In the state where the photoconductor, the transfer material, and the belt are stacked in close contact with each other in sequence, a transfer electric field is applied by corona discharge from the belt side. If necessary, a belt static eliminator may be provided. In this example, the solvent recovery device was omitted.

FIG. 6 shows a modification of the embodiment shown in FIG. The pulley is made of metal and is grounded. The transfer material is attached to the belt by the corona charging device being arranged toward the pulley in a device where the transfer material is superposed on the belt by the guide plate and facing the pulley, and the corona charging device charges the entire belt. In this embodiment, a roller transfer device is used instead of the corona transfer device, but the function is the same. The roller is energized. The other parts are the same as in FIG. 6 and are omitted.

According to the present invention, since the developing device is small and simple, the entire machine is downsized in any of the examples, and a desktop type machine is realized.

[0023]

As described above in detail and specifically, according to the present invention, the resolution and gradation reproducibility are excellent, the solid uniformity is sufficient, and the photographic reproducibility is good. It is possible to obtain a system that is not complicated and that is largely maintenance-free. Further, since the developing unit is miniaturized, there is a remarkable effect that a color printer using a wet type electrophotographic desktop can be realized.
It is expected to have the power to shape the market for new color printers.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a developing device of a small wet type color printer, which is the basis of the present invention.

FIG. 2 is a diagram showing a non-developed state (a) and a developed state (b) of the developing device according to the present invention.

FIG. 3 is a diagram showing an example of a wet compact color printer using the developing device of the present invention.

FIG. 4 is a diagram showing another example of the wet compact color printer of the present invention.

FIG. 5 is a diagram showing still another example of the wet compact color printer of the present invention.

FIG. 6 is a diagram showing still another example of the wet compact color printer of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Exposure device 4 Development part 4a Developer tank 4b Developer 4c Development roller 4d Rubber blade 4e Support shaft 4f Developer layer thickness 5 Blanket 6 Heater 7 Static eliminator 8 Cleaning part 8a Blade 8b Seal plate 8c the feed vanes 9 feed roller 9b conveyor belt 9c guide plate 9d pulley 9g feed roller 10 fixing device 11 heater 12 charging unit 13 pressing roller 14 solvent recovery port 15 inlet means 16 electrostatic device 17 solvent recovery port 18 minutes Toki pawl 19 conductive Plate 20 Conveyor Belt 21 Transfer Material (Paper) 22 Paper Tray 23 Separation Claw

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G03G 15/10 (56) Reference JP-A-3-144668 (JP, A) JP-A-7-239614 (JP, A) Special Kaihei 8-6404 (JP, A) JP 5-45997 (JP, A) JP 3-155582 (JP, A) JP 7-230220 (JP, A) JP 3-267971 ( JP, A) JP 6-19267 (JP, A) Actual opening 57-78055 (JP, U) Actual opening 63-20170 (JP, U) Special table 5-508026 (JP, A) Special table Flat 6-500406 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/01-15/01 117 G03G 15/10-15/11 G03G 15/08-15/095 G03G 21/10

Claims (13)

(57) [Claims] 1. A charging device, an exposing device, a developing device, a transferring device, a fixing device, a discharging device, and a cleaning device are arranged around a drum-shaped photosensitive member having a photosensitive layer on a conductive substrate. An electrophotographic color printer having a paper device and a paper discharge device, wherein the developing device is black,
The developing sections for the four color developing solutions of yellow, magenta and cyan are arranged in parallel, and the developing sections are mainly the developing solution tank, the developing solution, the developing roller, the developing-non-developing control section, the developing solution. And a developing / non-developing control unit that also functions as the developer pumping thickness control unit.
When the roller and the photoconductor are placed in contact with each other, non-development
Occasionally, the pressure is applied to the developing roller, and suction is applied to the contact area.
Can completely prevent pumping up to the extent that there is no developer
Ones, still has a solvent recovery device optionally small electrophotographic color printer using a liquid toner. 2. A means for turning on / off carrying of a developing solution on a developing roller in the developing device is performed by urging and releasing a doctor blade made of resin on the developing roller. Claim 1
The small electrophotographic color printer described. 3. The optical system according to claim 1, wherein the exposure device is an optical system of any one of laser scanning, LED irradiation, plasma display irradiation, EL irradiation, and a combination of a light source and a liquid crystal shutter. Small electrophotographic color printer. 4. The miniature electrophotographic color printer according to claim 1, wherein the charging device and the transfer device are formed by corona discharge or voltage application roller charging. 5. A device for separating toner particles and carrier liquid from the used developer collected by the cleaning device is mounted, and means for recycling only the carrier liquid to the developer tank is provided. The small electrophotographic color printer according to claim 1. 6. The method according to claim 1, wherein the transfer of the four-color repetitive transfer and the post-transfer material which has undergone fixing in or after the transfer is released from the conveying device and guided to the paper discharge path is performed by moving the claw. 5. The small electrophotographic color printer described in any one of 5. 7. The fixing device according to claim 1, wherein the fixing device is heated by an ordinary heat roller or by a heater directly or indirectly from the back side of the transfer material (the side opposite to the toner adhering surface). The small electrophotographic color printer described in any one of 1. 8. A toner image is formed by subjecting the photosensitive layer of a drum-shaped photoreceptor having a photosensitive layer on a conductive substrate to each of black, yellow, magenta, and cyan for charging, exposing, and developing to form a toner image. The toner image is transferred to a blanket adjacent to the photoconductor by pressing and / or heating and / or applying an electric field, and the toner image formed on the blanket is pressed and / or heated and transferred from the blanket to a transfer material. And / or an electrophotographic color image forming method including a step of repeating a step of transferring by applying an electric field four times, and fixing a toner image on the transfer material as necessary, wherein the developing treatment step is performed for each of the four colors. Of the developing units arranged side by side, each developing unit comprising a developing tank, a developing solution, a developing roller, a developing-non-developing control section, a developing solution pumping thickness control section for the developing roller, and the developing section. Non-present The image control unit determines the pumping thickness of the developer.
Also serves as a control unit, and also contacts the developing roller and the photoconductor.
When not installed in the development state,
By the pressure contact, there is no developer sucked into the contact part.
An electrophotographic color image forming method characterized in that it can completely prevent pumping up . 9. The image forming method according to claim 1, wherein the toner image is transferred onto a transfer material by applying an electric field, and this process is repeated up to the fourth color, and then a fixing process is performed if necessary. 8
The method for forming an electrophotographic color image according to 1. 10. A drum-shaped photoreceptor having a photosensitive layer on a conductive substrate, wherein black, yellow, magenta,
A toner image is formed by performing charging, exposure, and development processing for each color of cyan, and the toner image is transferred to a paper conveyed on an endless belt made of an insulating resin without mechanical clamping,
A transfer electric field is applied from the back side of the belt by a corona charging or voltage application roller to transfer, and fixing is performed if necessary, and after repeating the process 4 times, the transfer paper is separated from the endless belt and fixing is performed if necessary. An electrophotographic color image forming method including a step of applying, wherein the developing processing step is performed in developing units arranged in parallel for each of the four colors, each developing unit including a developing tank, a developing solution, a developing roller, The developing-non-developing control unit and the developer pumping thickness control unit for the developing roller, and the developing-non-developing control unit also functions as the developer pumping thickness control unit.
I installed the developing roller and the photoconductor in contact with each other.
When not developing, press contact with the developing roller
Pump up so that there is no developer sucked into the contact area.
A method for forming an electrophotographic color image, which is capable of completely preventing the above problems. 11. The transfer material is conveyed by the endless belt for conveyance by charging the transfer material by a corona discharger facing a grounded guide plate provided in the paper conveyance process before the transfer material is attached to the paper. 11. The electrophotographic color image forming method according to claim 10, wherein the electrophotographic color image forming method is performed by an electrostatic attraction force between the electric charge and a belt and / or a driving pulley that is grounded. 12. The transfer material is conveyed by the endless belt for conveyance at a position where the transfer material is fitted to the belt, by charging the transfer material by a corona discharger provided opposite to a grounded pulley. The electrophotographic color image forming method according to claim 10, which is characterized by: 13. A toner image is formed by subjecting a photosensitive layer on a drum-shaped photosensitive body having a photosensitive layer on a conductive substrate for each color of black, yellow, magenta, and cyan to a toner image by charging, exposing, and developing. Repeat the process of transporting the material to the transfer position and directly transferring the toner image on the photoconductor to the transfer material for each color, fixing the toner image on the transfer material as necessary, and fixing if necessary. An electrophotographic color image forming method including a step of applying and ejecting paper, wherein the developing process is performed in developing units arranged in parallel for each of the four colors, each developing unit including a developing solution tank, a developing solution, and a developing solution. A roller, a development / non-development control section, and a developer drawing-up thickness control section, and the development-non-development control section also serves as the developer drawing-up thickness control section.
When the roller and the photoconductor are placed in contact with each other, non-development
Occasionally, the pressure is applied to the developing roller, and suction is applied to the contact area.
Can completely prevent pumping up to the extent that there is no developer
What is claimed is: 1. An electrophotographic color image forming method, comprising: