JPS6163856A - Polychromatic picture forming method - Google Patents

Abstract

PURPOSE:To form plural color-decomposed latent images only by one image exposure and to obtain a polychromatic picture of high quality by using a photosensitive body having an insulating layer containing filter distribution layers for different colors on its photoconductive layer and smoothing the potential of the photosensitive body before the 2nd exposure or after of the whole surface. CONSTITUTION:After exposing an image while electrifying the surface of the photosensitive body having the insulating layer 3 containing the fine filter distribution layers 3a for different colors on its photoconductive layer 2, the whole surface of the photosensitive body is exposed to specific light to form a potential pattern on a part corresponding to a specific filter in the filters 3a. Then, the electrostatic latent image is developed. In the polychromatic picture formation repeating picture formation twice or more, charging process for smoothing the potential on the surface of the photosensitive body is executed prior to each whole surface exposure after the 2nd operation. The smoothing of the potential on the surface of the photosensitive body prior to the whole surface exposure after the 2nd operation makes it possible to prevent a toner adhering part in the preceding development from being reduced sufficiently at its potential and adhesion of other toner and execute the succeeding toner image transfer efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel multicolor image forming method using a multicolor image forming photoreceptor for forming multicolor images using electrophotography.

[Prior art]

Many methods and devices used therefor have been proposed for the purpose of obtaining multicolor images using electrophotography, but they can generally be classified into the following types. One method is to repeatedly form a latent image and develop with color toner according to the number of separated colors using a photoreceptor, or to overlap the colors on the photoreceptor each time, or to transfer the colors to a transfer material each time the development is performed. This is a method of layering. Another method uses a device having multiple photoconductors corresponding to the number of separated colors, exposes each photoconductor with a light image of each color at the same time, and uses color toner to cover the latent image formed on each photoconductor. In this method, the images are developed and sequentially transferred onto a transfer material to overlap the colors to obtain a multicolor image.

The first method has a major drawback in that it is necessary to repeat a plurality of latent image formation and development processes, and it takes time to record an image, making it extremely difficult to speed up the process. In addition, in the case of overlapping toner images on a photoreceptor, the potential drop in the previously developed toner adhering area is not sufficient.
Another drawback is that toner to be developed later tends to adhere to previously developed toner areas that should not originally adhere, resulting in color smudging.

The second method uses multiple photoreceptors in parallel, so it is advantageous in terms of high speed, but it requires multiple photoreceptors, an optical system,
Since a developing means and the like are required, the apparatus is complicated, large-sized, and expensive, which has the disadvantage that practicality is limited.

Furthermore, both types have a major drawback in that it is difficult to align images during image formation and transfer a plurality of times, and it is not possible to completely prevent image color misregistration.

In order to fundamentally solve these problems, K should record a multicolor image on a single photoreceptor with one image exposure, but the reality is that such a system has not yet been developed.

[Purpose of the invention]

The present invention has been made in view of the above circumstances.-
It is possible to form electrostatic latent images with multiple color separations through multiple image exposures, so there is no color blurring, and the toner to be developed later will adhere to the previously developed toner adhesion area. The object of the present invention is to provide a multicolor image forming method that can form high-quality multicolor images at high speed and through a simple process.

[Structure of the invention]

The present invention provides a photoconductive layer on a conductive member.

After performing image exposure while charging the surface of the photoreceptor using a photoreceptor having an insulating layer □ including a distribution layer of fine filters of different colors on the photoconductive layer, A step of exposing the entire surface of the photoreceptor to specific light to form a potential pattern on a portion of the filter corresponding to the specific filter, and a step of developing an electrostatic latent image formed thereby, depending on the type of filter. A multicolor image forming method that is repeated at least two times or more according to the desired condition, characterized in that a charging process is performed to flatten the potential of the photoreceptor surface before every second and subsequent full-surface exposure. The present invention is an image forming method, and this configuration achieves the above object.

〔Example〕

The present invention will be described below with reference to illustrated examples.

Note that all the illustrated examples are red, which transmit red light, green light, and blue light, respectively, as color separation filters (filters that transmit only light in a specific wavelength range).

Although an example is shown in which three types of filters, green and blue, and three corresponding color toners are used, the present invention is not limited to such number of color combinations.

Figures 1 to 4 are cross-sectional views schematically showing the structure of a photoreceptor using 8Alc according to the present invention, and Figures 5 to 7 are examples of filter arrangement of the filter distribution layer in the insulating layer of the photoreceptor. The top view shown in FIG. 8 implements the method of the invention. FIG. 9 is a schematic block diagram showing an example of the apparatus, FIG. 9 is a process diagram of the method of the present invention, and FIG.

In Figures 1 to 4, 1 is a conductive material made of metal such as aluminum, iron, nickel, copper, or an alloy thereof, and formed into an appropriate shape or structure as required, such as a cylindrical shape or an endless belt shape. Photoconductors such as parts, 2 sulfur 1 selenium, amorphous silicon or alloys containing sulfur, selenium, tellurium, arsenic, antimony, etc., or oxides of metals such as zinc, aluminum, antimony, bismuth, cadmium, molybdenum, etc. , iodide, sulfide, selenide, or organic photoconductive substances such as vinylcarbazole, anthracenephthalocyanine, t')nitrofluorenone, polyvinylcarbazole, polyvinyl anthracete/, polyvinylpyrene, etc. 3 is a photoconductive layer consisting of an organic photoconductor dispersed in an insulating binder resin such as polyester, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, acrylic resin, silicone resin, fluororesin, or epoxy resin; Red (R1, @(Gl, blue (B)) formed from various polymers, resins, etc. and colorants such as dyes.
This is an insulating layer including a distribution layer 3a of a color separation filter.

The insulating layer 3 in the photoconductor shown in FIG. 1 is formed by printing an insulating material such as a resin colored with a coloring agent to form a color separation filter onto the photoconductive layer 2 in a predetermined pattern. The insulating layer 3 of the photoreceptor shown in FIG. 2 is formed by first forming a transparent insulating layer on the photoconductive layer 2 by a conventionally known means, and then applying a coloring agent, a colored resin, etc. to the surface of the transparent insulating layer. The insulating layer 3 in the photoreceptor shown in FIG. 3, which is formed by adhering it in a predetermined pattern by means such as printing or vapor deposition, is formed by further providing a transparent insulating layer on the insulating layer 3 shown in FIG. 2 by a conventionally known means. The fourth
The insulating layer 3 in the photoreceptor shown in the figure can be formed by depositing a colorant in a predetermined pattern on the photoconductive layer 2 by direct printing, vapor deposition, or other means, or on the insulating layer 3 shown in FIG. K, 3rd
Similar to the insulating layer 3 in the figure, it is formed by providing a transparent insulating layer. The formation of the insulating layer 3 is not limited to the above example, but it is also possible to first form an insulating film or sheet containing the distribution layer 3a of the color separation filter, and then attach it on the photoconductive layer 3 by an appropriate means. Alternatively, it may be adhesively bonded.

The distribution layer 3a of the color separation filter, which is formed by the adhesion of colorants, colored resin, etc., on the insulating layer 3 has R, G,
Although the shape and arrangement of the fine filters such as B are not particularly limited, it is preferable to have a striped distribution as shown in Figure 5 because pattern formation is easy, and a delicate multicolor image can be reproduced. A mosaic distribution as shown in FIGS. 6 and 7 is preferable because of the fact that this is possible. The direction in which the R, G, B, etc. filters are arranged may be in any direction in the spreading direction of the photoreceptor, not only in a mosaic distribution but also in a stripe distribution. That is, for example, in the case of a rotating drum-shaped photoreceptor, the length direction of the stripes may be parallel to or perpendicular to the axis of the photoreceptor, or may be spiral. The types of filters are not limited to the three types of R, G, and B, but also the three types of filters of other colors, such as Y (yellow) and M (
Magenta), C (cyan), or when used for two colors instead of full color, it may be a color separation filter in which a white light transmitting part and a specific color light (for example, red) transmitting part are distributed. Good too. R (red).

If the individual sizes of filters such as G (M) and B (blue) are too large, the resolution and color mixing properties of the image will decrease, resulting in deterioration of the image quality, and if they are too small, the particle size of the toner particles will deteriorate. Even if the value is the same as or lower than that, it will be easier to be influenced by other adjacent color parts and it will be difficult to form a filter distribution pattern.
In the case of food filter distribution, it is preferable that the width or size is such that the length l of one cycle of the repeating arrangement is 30 to 300 μm. Of course, if the number of types of filters changes, the preferred range of the above-mentioned length l will also change.

The image forming apparatus shown in FIG. 8 forms a multicolor image by the method of the present invention using a drum-shaped image carrier 4 made of the photoreceptor as described above. That is, the image carrier 4 rotates in the direction of the arrow, the charger 5 charges its surface to a uniform potential, and the image exposure device 6 emits reflected or transmitted light from scanning the document with white light onto the charged surface. While being charged with a charger that performs alternating current or corona discharge of the opposite sign to the charger 5, image exposure is performed by making the light incident through the slit of the charger, and then a color exposure device 7B applies a blue filter to the charged surface. The blue light LB passed through the FB is incident uniformly, thereby forming an electrostatic latent image that provides a complementary color image of blue on the image exposure surface, and the electrostatic latent image is developed using yellow toner as a developer. The developing device 1t8Y develops the image, and the charger 9Y, which performs a corona discharge similar to the charger of the image exposure device 6, discharges the image carrier 4 after development to smooth the potential of the image carrier 4. The color exposure device 7G has a green filter F on the surface. Green glow through. uniformly enters the image to form an electrostatic latent image giving a complementary color image of green, and the developing device 8M using magenta toner as a developer develops the electrostatic latent image. A charger 9M similar to the charger 9Y performs corona discharge to smooth the potential of the image carrier 4, and a color exposure device 7R uniformly impinges red light LR passed through a red filter FR onto the smoothed surface. The electrostatic latent image is then developed by the developing device 8G, which uses cyan toner as a developer, thereby forming yellow, magenta, and cyan colors on the image bearing surface. A multicolor image consisting of a superposition of three color toner images is formed. This multicolor image is transferred to a recording paper P fed by a paper feeding device (not shown) by a transfer device 10.
The transferred recording paper is separated from the four surfaces of the image carrier by a separator 11, the multicolor image is fixed by a fixing device (not shown), and the transferred recording paper is discharged outside the machine. The surface of the image carrier onto which the multicolor image has been transferred is neutralized by a static eliminator 12 that performs exposure and discharge, and residual toner is removed by a cleaning device 13, returning to a state in which the next multicolor image can be formed.

Each step of the multicolor image forming method of the present invention, which is carried out by the apparatus shown in FIG. 8 as described above, will be further explained with reference to FIG. Note that FIG. 9 shows an example in which an n-type semiconductor photoconductor such as cadmium sulfide is used in the photoconductive layer 2 of the image carrier 4, and FIG. The same reference numerals indicate the same functional members.

FIG. 9(1) shows a state in which the image carrier 4 rotates and is uniformly charged by the positive corona discharge of the charger 5, and a positive charge is generated on the surface of the insulating layer 3, and a corresponding charge is generated on the surface of the insulating layer 3. As a result, a negative charge is induced at the interface between the photoconductive layer 2 and the insulating layer 3, and as a result, the surface of the image carrier 4 exhibits a uniform potential as shown in the graph of the potential E (Fig. 9 [2]). ] indicates a change in the charged surface due to the red component LR of the original image exposure that is incident on the charged surface by the image exposure device 6, and the red component LR passes through the R filter portion of the insulating layer 3 and becomes the light below it. Since the conductive layer 20 portion is made conductive,
In that part, the negative charge on the interface between the photoconductive layer 2 and the insulating layer 3 disappears, and the positive charge on the surface of the insulating layer 30 is also erased by the discharge from the charger of the image exposure device 6, so that no charge exists. (From the top of explaining the principle, the red component L
This article focuses on the strong parts of R. ).

On the other hand, since the G and B filter portions do not pass the red component LR, the negative charges of the photoconductive layer 2 remain as they are in those portions, and even if discharge is performed by the discharger, the image exposure device After passing through position 6, positive charges are induced on the surface of the insulating layer 3 by the negative charges of the photoconductive layer 2. but,
In addition to the R filter part where the charge has disappeared, there is still a charge of 6G.

In the B filter section, the surface potential of the image carrier 4 due to positive and negative charges is balanced and becomes almost 0 as seen in the graph of potential E.
becomes. Although not shown in FIG. 9, the green and blue components of imagewise exposure give similar results, and their integrated state is the state in which imagewise exposure is performed by the imagewise exposure device 6. , this state does not function as an electrostatic image1
This is the state in which the next latent image has been formed.

FIG. 9 [3] shows that the blue filter FB is exposed by the color exposure device 7B.
This shows a state in which the blue light LB that has passed through is uniformly incident on the above-mentioned image exposure surface. The blue light LB does not pass through the R and G filter parts, so it does not affect those parts, but it passes through the B filter part and makes the photoconductive layer 2 below it conductive, thereby changing that part. The charges at the upper and lower interfaces of the photoconductive layer 2 are neutralized, and as a result, a B filter portion is formed on the surface of the insulating layer 30 by the previous image exposure.
A potential that gives a complementary color image appears as shown in the graph of potential E.

FIG. 9 (4) shows that the electrostatic latent image formed by uniform exposure of blue light LB is negatively charged, and yellow toner T of the complementary color of 9B is used.
1 is developed by a developing device 8YK using No. 1 as a developer. The yellow toner TY adheres only to the #B filter portion that shows potential, and does not adhere to the R and G filter portions that do not show potential. As a result, one color of yellow toner is formed on the surface of the image carrier 4 as a color separation layer. The potential of the B filter part is yellow toner T
Although it decreases due to the adhesion of Y, it still remains as shown in the graph of potential E, and in the next development, another toner may adhere to this area, causing color smudges.

FIG. 9 [5] shows a state in which corona discharge is applied from the charger 9YK to the surface of the image carrier 4 that has been developed by the developing device 8YK in order to prevent other toner from adhering to the B filter portion. It shows. This discharge by the charger 9YK, unlike the strong discharge by the charger 5, has almost no effect on the R and G filter parts, and mainly lowers the potential of the B filter part to which yellow toner T is attached. . Therefore, the surface potential of the image carrier 4 uniformly becomes K, which almost shows O, as seen in the graph of the potential E.

This prevents other toner from adhering to the B filter portion to which the yellow toner TY has adhered in the next developing step, and color smearing is prevented from occurring.

Therefore, this yellow toner image is formed in Fig. 9 [5].
] The surface of the image carrier 4 is illuminated with green light by the @jlE optical device 7G. When uniform exposure is performed, an image potential appears in the G filter portion, as described in FIG. 9 [3]. When this electrostatic latent image is developed by a developing device 8MK using magenta toner as a developer, the magenta toner adheres only to the G filter portion and a magenta toner image is formed as in FIG. 9 [4]. This means that the two color toner images are superimposed. Corona discharge is also performed on this image forming surface by the charger 9M to lower the potential of the G filter portion to which the magenta toner has adhered, thereby preventing other toner from adhering to that portion.

Further, when the color exposure device 7RK uniformly exposes the surface of the image carrier 40 with the red light LR on which the two-color toner image is formed, the red light LR is uniformly exposed to the red light LR as described in FIG. 9 [3].
Since an image potential appears in the filter portion, the electrostatic latent image is developed by the developing device 8C using cyan toner as a developer, and a cyan toner image is formed. As a result,
A clear three-color image without color shift or color turbidity is formed on the image carrier 4.

The above-mentioned FIG. 9 shows an example in which an n-type optical semiconductor is used for the photoconductive layer 2 of the image carrier 4.
Of course, it is possible to use a p-type optical semiconductor such as selenium, and in that case, the basic process is the same except that the positive and negative signs of the charges are all reversed. Note that if it is difficult to inject charges into the image carrier 4 by the charger 5,
Uniform irradiation with light may also be used. Also, Figure 9 [2
] The surface potential of the image carrier 4 after being charged was set to almost 0, but it does not matter if it is slightly biased toward the positive or negative side. Table 1 shows the colors of the original image and the three-color separation method described above. The relationship between image formation using three primary color toners using the nine-subtractive color method is shown. 1 in the table.
rJ, 1 is a primary latent image, O is an electrostatic latent image, ・ is a toner image, ↓ is a state in which the state in the upper column is maintained, and empty state is a state in which no image exists. . Also, - in the attached toner column indicates that no toner is attached, Y, M, (3
indicates that yellow toner, maze/tatoner, and cyan toner are attached, respectively.

It shows the situation where the surface potential at G and H changes according to the image formation process described above, and the horizontal axis is 5°6.7B, B.
Y, 9Y, 7G, 8M, 9M, 7R.

8C indicates a step in which the same reference numerals in FIG. 8 or 9 act on the image carrier 4, and B, G, R
indicates the highest or average potential of each filter section.

The development in the image forming method of the present invention is preferably carried out by a magnetic brush method, and the developer can be either a so-called one-component developer consisting only of toner or a two-component developer using toner and a magnetic carrier. For development, a method of directly rubbing with a magnetic brush may be used, but in order to avoid damage to the formed toner image, especially after the second development, a developing method in which the developer layer does not come into contact with the photoreceptor surface is used, such as in the United States. Patent No. 3,893,418 specification, Japanese Patent Application Laid-open No. 55-1
Publication No. 8656, Japanese Patent Application No. 58-57446, Japanese Patent Application No. 1983
No. 8-238295, patent application 1982-”23'8'296
It is particularly preferable to use a method such as that described in the specifications of "Fune".This method uses a component developer containing non-magnetic toner that can be freely selected for coloring, and forms an alternating electric field in the developing area. Developing is carried out without contacting the image carrier and the developer layer.Developing is carried out without substantially contacting the developer layer with the image carrier, because the developer in the image carrier and the developing device This is done by setting the gap between the developer sleeve that transports the layer wider than the thickness of the developer layer that is transported to the development area.

The color toner used for development is made using known techniques and consists of known binding resins, organic and inorganic pigments, various chromatic and achromatic colorants such as dyes, and various magnetic additives that are commonly used in toners. Toner for developing electrostatic images can be used, and the carrier can be iron powder, ferrite powder, which are usually used for electrostatic images, resin coatings thereof, or resin-coated toners with magnetic substances dispersed in the resin. Various known carriers such as magnetic carriers can be used.

Also, this case - patent application No. 58-24966, which the applicant previously filed.
9 and 24oo66M may be used.

In the present invention, as a charger for charging the surface of the image bearing member that has been developed before every second and subsequent full-surface exposure, a charger that performs biased or unbiased AC corona discharge is used. , or a DC charger is used. In particular, in the case of a DC charger, a corotron charger with a grid that can control the charging potential is preferable to a corotron charger with only a charging wire, and the charging potential is almost the same as that at the end of the secondary charging simultaneous image exposure process. Preferably, it is a potential. For example, if the secondary charging simultaneous image exposure process ends at Ov, and the potential of the toner adhesion area is biased towards positive, set the grid of the scorotron charger to approximately Ov (grounded, for example) and apply a negative voltage to the charging wire. Just apply it.

The effect of the above-mentioned charging treatment is that it sufficiently lowers the residual potential of the area to which toner has adhered due to the previous development and prevents other toner from adhering to the same area, as described above. In addition, the upper ILty) piece of the potential on the surface of the image carrier due to the dark decay of the potential of the photoconductive layer +Lll'hJ
RJ--MIF), Su-41 (1~f a
It is also possible to obtain the effect of imparting a sufficient amount of charge to the toner so as to cause the toner to have an impact. In order to compare this with the embodiment of the present invention described in FIGS. 8 and 9, a three-color image was created under the same conditions except that the chargers 9Y and 9M immediately after the developing devices 8Y and 8M were removed. When the image was formed, the recorded image obtained had poor color tone and was very inferior to the original image.

On the other hand, according to the embodiment of the present invention described above,
Not only was it possible to obtain a recorded image with vivid colors that were almost the same as the original image, but the toner transfer rate was also improved.
The effect of reducing the amount of toner collected by the cleaning device 13 was also obtained.

As is clear from the above, the charging process immediately after development is extremely important for obtaining a good multicolor image.

Specifically, in the image forming apparatus shown in FIG.
consists of a photoreceptor with the layer structure shown in Figure 4, and the photoconductive layer 3 has a layer thickness of 3.
The insulating layer 4 is made of CdS with a thickness of 0 μm and has a layer thickness of 20 μm.
m, and t of the distribution of R, G, and B filter parts in Figure 6 is 1.
including a filter layer 4a with a diameter of 00 μm and a diameter of 120 W
It is assumed that the image bearing member 4 rotates in the direction of the arrow at a surface speed of 200 M/Sec, and the surface potential of the image carrier 4 becomes 1.5 kV after being charged with the charger 5 using a corotron charger.
The charger of the image exposure device 6 is assumed to have a voltage of 1200V on the surface of the image carrier 40 after discharging with a scorotron charger, and each of the developing devices 8Y to 8C is a developing sleeve with an outer diameter of 25 mm made of non-magnetic stainless steel. rotates counterclockwise at a rotation speed of 153 rpm, and the internal magnet body touches the surface of the developing sleeve up to 8
The magnetic brush developing device has eight magnetic poles in the circumferential direction giving a magnetic flux density of 00 G and rotates clockwise at a rotational speed of soo rpm to convey a developer layer, and includes an image carrier 4 and each developing device 8Y to The surface gap with the developing sleeve of 8C is 1 inch,
Each of the developing devices 8Y to 8G has an average particle diameter of 10 μm for yellow, magenta, and cyan, and a triboelectric charge amount of −10 to −20 μ0/? toner with an average particle size of 25 μm
A developer layer is formed on the developing sleeve of each developing device ff8Y to 8C using a developer mixed with a carrier made of a resin containing dispersed magnetic material having a resistivity of 10 Ωcm or more at a weight ratio of 1:4. The layer thickness is 5W5+1, and when each developing device 8Y to 8C performs development, a developing bias consisting of a DC voltage of 1150 cm and an AC voltage with an effective value of 1 kV and a frequency of 2 kHz is applied to the developing sleeve. The smoothing by the chargers 9Y and 9M is performed under the following conditions: -200V DC voltage is applied to the back plate and 6 kV AC voltage is applied to the charging electrode in the first example, and the back plate is smoothed in the second example. Grounded and charged electrode -5,5k
When three color images were copied under the conditions of applying a DC voltage of V and setting the grid voltage to -200V, the first. In each of the second examples, there was no color shift at all, and extremely clear images with good color reproduction were obtained.

All of the above explanations have been made regarding examples of color copying machines that use so-called three-color separation filters and subtractive three-primary-color toner, but the present invention is not limited to the illustrated example, and the number and color of separation filters and It goes without saying that the combination of toner color and the corresponding toner color can be arbitrarily selected depending on the purpose. For example, processes for obtaining two-color copies are also conceivable.

In such a process, if a photoreceptor with G filter depths distributed in a scattered manner is used, and the original is made up of two colors, red and black, the process is basically the same as above. When using the process (however, the entire surface is exposed using G and R or G and B), for the black part of the original, a black copy part that is almost black, consisting of black toner and red toner, is obtained as a copy. For the red part of , there is a process that yields a red part made of red toner.

Therefore, the photoreceptor that has a distribution layer of "multiple types of filters" in the explanation so far has a layer consisting of a single type of color separation filter and a part without a filter (which may be transparent resin or air, etc.). It may also be a photoreceptor, and in this case, the portion without the filter closure is regarded as a transparent filter and included in the plurality of types of filters.

In addition, "charging" in the above description includes cases where the surface potential of the photoreceptor becomes O when charging is performed, and cases where the surface charge disappears.

Furthermore, in the above explanation, the spectral characteristics of light for full-surface exposure can be obtained by using green (G), blue (B), and red (R) filters 4N, but they cannot be obtained by means other than filtering. However, its spectral characteristics are also G
, B, and H, but in short, a spectral filter that forms a latent image only on a specific filter Any characteristic is fine.

Further, in the present invention, a color exposure device that switches and uses a plurality of color filters is provided only at one location between the image exposure device and the development device, and the color exposure device is provided at only one location between the image exposure device and the development device, and the color exposure device is configured to switch between a plurality of color filters. It is also possible to use an image forming apparatus in which the filter is changed and a discharger of the image exposure device is used for the charging process immediately after development, that is, an image forming apparatus in which toner images are superimposed every rotation.

〔Effect of the invention〕

According to the multicolor image forming method of the present invention, one image exposure is required to form electrostatic latent images for each color, so there is no color shift in the multicolor image, and the toner image is During overlaying, another toner does not adhere to the area where the toner previously adhered, so there is no color fading, and therefore clear bird-quality images with no color shift can be recorded. Image formation can be performed at high speed, and the device is compact because the image carrier, exposure and scanning drive unit, etc. need to be as simple as a monochrome copying machine.

It can be formed at low cost and has many excellent effects such as improved reliability.

[Brief explanation of the drawing]

FIGS. 1 to 4 are cross-sectional views schematically showing the structure of a photoreceptor used in the present invention, and FIGS. 5 to 7 are examples of filter arrangement of a filter distribution layer in an insulating layer of the photoreceptor, respectively. FIG. 8 is a schematic configuration diagram showing an example of an apparatus for carrying out the method of the present invention, FIG. 9 is a process diagram of the method of the present invention, and FIG. This is a graph chronologically showing the states in which DESCRIPTION OF SYMBOLS 1... Conductive member, 2... Photoconductive layer, 3...
...Insulating layer, 3a...Distribution layer of color separation filter, 4...Image carrier, 5...Charger, 6...
・Image exposure device, 7B, 7G: 7R...Color exposure device, FB...
・Blue filter% Fo...Green filter, FR・
...Red filter, LB...Blue light, L, ,--Green light, LR...Red light, 8Y, 8m[,
80--Developing device, 9Y, 9M... Charger,
P...Recording paper, 10...Transfer device, 11...Separator, 12...Static eliminator, 13...Cleaning device. Patent applicant Konishiroku Photo Industry Co., Ltd. 1WA Figure 2 Figure 3 Figure 416 Figure 5 @ Figure 6 Figure 7 Procedural amendment March 30, 1985

Claims (1)

[Claims] A photoconductive layer is provided on a conductive member, and a photoconductor is provided with an insulating layer including a distribution layer of fine filters of different colors on the photoconductive layer, and the surface of the photoconductor is charged. After imagewise exposure is performed, the entire surface of the photoreceptor is exposed to specific light to form a potential pattern on a portion of the filter that corresponds to the specific filter, and an electrostatic latent image formed thereby. A multicolor image forming method in which the developing step is repeated at least twice or more depending on the type of filter, and a charging process is performed to flatten the potential of the photoreceptor surface before each second and subsequent full-surface exposure. A multicolor image forming method characterized by: