JPS6173964A - Formation of polychromatic image - Google Patents

Abstract

PURPOSE:To obtain a polychromatic image which has neither a deficiency in density nor color blurr at a high speed by adding development which uses black toner among repetitive processes of the electrostatic charging, image exposure, entire-surface exposure using light having a spectral distribution, and color toner development as to a photosensitive body which has a layer containing plural filters. CONSTITUTION:The photosensitive body 4 which has the layer 3 containing plural filters R, G, and B having mutually different spectral transmissivity characteristics, a photoconductive layer, and a conductive layer is charged electrostatically and exposed to an image, and then entire-surface exposure using light having a different spectral distribution at each time and development of a formed electrostatic latent image with toner of different colors 8C, 8M, and 8Y are performed several times to form a polychromatic image on the photosensitive body 4. In this case, development using black tone 8K is added among those repetitive processes of development. Consequently, the polychromatic image is formed on the surface of the photosensitive body 4 by using toner of four colors without color blurr nor color mixing. This image is transferred to a transfer material P and fixed to obtain the sharp polychromatic image which has no deficiency in density and superior contrast.

Description

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

[Prior art]

Conventionally, the following two methods have been known as multicolor image forming methods using electrophotography. The first method uses a common photoreceptor for each color, and electrostatic Either the formation of a latent image and the development for each color are repeated, and the toner images for each color are superimposed on the photoreceptor, or the toner images for each color are transferred to the transfer material each time the development for each color is performed, and the toner images for each color are transferred to the transfer material. This is a method in which toner images of different colors are superimposed. The second method uses multiple photoreceptors for each color, forms and develops electrostatic latent images for each color, and sequentially transfers the color-specific toner images formed on each photoreceptor. This first method does not require repeating the formation of electrostatic latent images for each color and the development for each color.
The drawback is that it takes time to form a multicolor image, and it is difficult to speed up the process. The second method is advantageous in terms of speedup because multiple photoreceptors can be used in parallel, but it requires multiple photoreceptors and their respective optical systems, developing means, etc., making the device complicated and The drawbacks are that it is large, expensive, and not practical. In addition, both of the above methods have 1
This method has a major drawback in that it is extremely difficult to superimpose color-specific toner images without misalignment, and color misregistration in multicolor images cannot be completely prevented.

In order to fundamentally solve these problems, the present inventors have previously invented a method that can form a multicolor image by performing one image exposure on a photoreceptor.

In this method, a photoreceptor having an insulating surface layer, a photoconductive layer, and a conductive layer forming a distribution layer of a plurality of filter portions having different spectral transmittance characteristics is charged and imagewise exposed. This is a method of forming a multicolor image on a photoreceptor by exposing the entire surface to light in a different color each time and developing the electrostatic latent image formed thereon with different color toners multiple times. According to this method, since the formation of an electrostatic latent image each time takes advantage of the previously performed charging and image exposure, there is no risk of color shift occurring in multicolor images. Further, since charging and image exposure, followed by full-surface exposure and development can be repeated during one cycle of the photoreceptor, three excellent effects can be obtained: high-speed multicolor image formation can be achieved. However, it has been found that this method has a problem in that the multicolor images formed are seen as lacking in density.

[Purpose of the invention]

The present invention was made in order to solve the problem of the multicolor images formed in the above-mentioned invention being considered to be insufficient in density, and it is possible to form multicolor images at high speed without color shift, and furthermore, To provide a multicolor image forming method in which a multicolor image does not appear to be lacking in density.

[Structure of the invention]

The present invention provides a photoreceptor having an insulating surface layer, a photoconductive layer, and a conductive layer forming a distribution layer of a plurality of filter portions having different spectral transmittance characteristics. After that, at least make a full exposure of a different color each time.
A method for forming a multicolor image on a photoreceptor by developing a well-formed electrostatic latent image with different color toners a plurality of times, including development with black toner during the repeated development. As for the characteristic multicolor image forming method,
This configuration achieves the above objective.

That is, in the present invention, the reason why the multicolor image formed by the method of the previous invention appears to be insufficient in density is that the reproduction of black in the multicolor image is also based on the additive coloring method using color toners of the three primary colors. In this additive coloring method, three primary color toners are arranged densely on a recording medium so that they do not overlap each other.
Relatively black is expressed by the combination of the reflected light from these color toners, but if the light reflection from these color toners is large, it will appear gray even if the colors are well balanced. As a result of this investigation, the problem of the method of Ama's invention was solved by using black toner to reproduce black in multicolor images.

〔Example〕

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

1 to 3 are partial plan views showing examples of distribution of filter portions in the insulating surface layer of the photoreceptor used in the present invention, FIG. 4114 is a graph showing an example of spectral transmittance characteristics of each filter portion, and FIG. The figures are graphs showing examples of the spectral transmittance characteristics of the filter portion that also transmits ultraviolet light, Figures 6 to 9.
The figures are a partial cross-sectional view schematically showing an example of the layered structure of a photoreceptor, FIG. 10 is a process diagram illustrating an example of the present invention, and FIG.
The figures are a schematic cross-sectional view showing an example of a recording apparatus that implements the method of the present invention, and a schematic cross-sectional view showing an example of a developing device used in the recording apparatus shown in FIG. 12 and FIG. 11.

In FIGS. 1 to 3, %T, B, G, and R are filter portions having spectral transmittance characteristics as shown in FIG. 4, respectively. Note that the spectral transmittance characteristics of the T filter portion may be such that the transmittance in the visible light region or the ultraviolet light region is changed as shown in FIG.

As will be described later, the T filter portion, which has a low transmittance in the visible light range, has a spectral transmittance characteristic as shown in FIG. 4, and therefore has a different effect from that of the filter portion.

However, unless otherwise specified below, it is assumed that the T filter portion has sufficient transmittance even in the visible light range as shown in FIG.

The insulating surface layer in FIG. 1 includes ribbon-shaped filter portions B, G,
Ribbon-shaped filter part molecule with narrow R! For example, when the photoreceptor is a rotating drum, the length direction of the stripe can be the circumferential direction, the direction perpendicular to it, or the helical direction. It can be in any direction. Such a striped pattern is preferable because it can be formed relatively easily. Second
The insulating surface layer shown in Figures and 3 consists of a mosaic distribution in which circular or square filter parts B, G, and R are arranged at intervals, and the empty ground part is the T filter part. Such a mosaic distribution is preferable because it allows relatively delicate multicolor image reproduction. Note that each filter portion in the insulating surface layer has T, B, G, R as described above.
The combination is not limited to the above example, but is a combination of multiple types of filter parts related to the color of the combination that synthesizes white light and at least a filter part that transmits light that does not pass through any of the filter parts. That's fine. If the colors and the number of types of filter parts related to the combination of colors that synthesize white light change, the colors and the number of types of color toner used for development will change accordingly. The number also changes depending on the number of color toners.

Also, the distribution pattern of each filter part is shown in Figures 1 to 3.
It is not limited to the illustrated example. However, if the individual sizes of the film molecules, B, G, R, etc., are too large, the image resolution and color mixing properties will decrease, resulting in deterioration of the image quality. If the particle size is the same as or smaller than the particle size, the toner adhesion K11i will be easily affected by the part of the filter that is in contact with it, and it will be difficult to form a distribution pattern. The length of l is preferably in the range of 10 to 200 μm, and the upper limit of the length of l' is preferably as narrow as 200 μm.

The insulating surface layer as described above is formed on the photoreceptor as shown in FIGS. 6 to 9.

In FIGS. 6 to 9, l is a conductive material formed of metal such as aluminum, iron, nickel, steel, or an alloy thereof into an appropriate shape or structure as required, such as a cylindrical shape or a heartless belt shape. Layer 2 is a photoconductor such as sulfur, selenium, amorphous silicon or an alloy containing sulfur, selenium, tellurium, arsenic, antimony, etc., or an oxide of a metal such as zinc, aluminum, antimono, bismuth, cadmium, molybdenum, etc. , iodide, sulfide, selenide, etc., or organic photoconductive substances such as vinylcarbazole, anthracenephthalocyanine, trinitrofluoro, polyvinylcarbazole, polyvinylanthracene, polyvinylpyrene, etc. to polyethylene, 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, epoxy resin, etc.; The above-mentioned R (red), B (blue), formed from polymers, resins, etc. and colorants such as dyes,
It is an insulating surface layer consisting of a color separation filter portion such as G (green) and a T filter portion that transmits light from the ultraviolet region to visible light. The insulating surface layer 3 in FIG. 6 is formed by printing on the photoconductive layer 2 an insulating material such as a resin colored with a coloring agent and a transparent resin without the addition of a coloring agent to form the color separation filter portion, respectively. The insulating surface layer 3 shown in FIG. 7 is formed by depositing it in a predetermined pattern by the method described above.The insulating surface layer 3 shown in FIG. The insulating surface layer 3 shown in FIG. 8 is formed by adhering a resin or the like in a predetermined pattern by printing, vapor deposition, etc., by further forming a transparent insulating layer on the insulating surface layer 3 shown in FIG. The insulating surface layer 3 shown in FIG. 9 can be formed by depositing a coloring agent on the photoconductive layer 2 in a predetermined pattern by direct printing or vapor deposition, or by applying the insulating surface layer 3 shown in FIG. On top, insulating layer # of Fig. 8
Similar to No. 3, a transparent insulating layer is provided.

The formation of the insulating surface layer 3 is not limited to the above-mentioned example, but it may also be previously formed into a film and then attached or adhered onto the photoconductive layer 2 by an appropriate means. Further, as can be inferred from the above-described forming method, the T filter portion may be formed by continuously forming a transparent resin forming a paste layer or a protective film.

The method of the present invention using the photoreceptor 4 having the layer structure as described above will be explained with reference to FIG. In addition, Fig. 10 shows
An example is shown in which an n-type photosemiconductor such as cadmium sulfide is used for the photoconductor M2 of the photoreceptor 4, but if a p-type photosemiconductor such as selenium is used, the positive and negative charges shown in the figure are All the basic processes are the same, just the signs are reversed.

First, as shown in FIG. 10 [1], the surface of the photoreceptor 4 is uniformly charged by positive corona discharge from the charger 5. In this state, a positive charge is generated on the surface of the insulating surface layer 3, and a corresponding negative charge is induced at the interface between the photoconductive layer 2 and the insulating surface layer 3. As a result, the surface of the photoreceptor 4 has a potential E As shown in the graph, it shows a uniform potential. If it is difficult to inject charges into the photoreceptor 4 during this charging, uniform irradiation with light is also used. The conductive layer 2 of the photoreceptor 4 is connected to the zero-order K which is grounded, and is connected to the exposure discharger 6 which has a % exposure slit and performs alternating current or negative corona discharge, as shown in [2], with respect to the above-mentioned charging surface. Imagewise exposure of a multicolor image is performed through an exposure slit along with a corona discharge.

In the figure, to simplify the explanation, the red component LR during image exposure is
I will discuss this in detail. In each process diagram, P indicates a bright area of image exposure, and D indicates a dark area of image exposure. Furthermore, when performing normal image exposure, it is desirable to cant light other than visible light.

The red component LR passes through the R and T filter portions of the insulating surface layer 3 and makes the portion of the photoconductive layer 2 below it conductive, so that in that portion, the insulating surface layer 3 of the photoconductive layer M2
The negative charge on the interface with the insulating surface layer 3 disappears, and the positive charge on the surface of the insulating surface layer 3 is also erased by the discharge of the exposure discharger 6, so that no charge exists.

Among these, the transmittance of the T filter part may be selected as shown in Figure 5 depending on the purpose of the image to be obtained, and instead of having sufficient transmittance in the visible light range, it may have low transmittance. When a material is used, the lower the transmittance, the more charge remains depending on the transmittance. On the other hand, since the B and G filter portions do not transmit the red component LR, the negative charges of the photoconductive layer 2 remain in those portions, and even if discharge is performed by the exposure discharger 6, the negative charges remain in those portions. After passing through the position, positive charges are induced on the surface of the insulating layer 3 by the negative charges of the photoconductive layer 2. However, not only the R and T filter parts where the charges have disappeared, but also the B and G filter parts where charges remain and the R, B, G, and T filter parts in the dark area are affected by the balance of positive and negative charges on the photoreceptor 4. The surface potential is almost O as seen in the graph of potential E. In other words, where the red component LR of the image exposure is strongly incident to the R and T filter parts so as to eliminate the charge, the charge disappears, but where it is not so strongly incident, the R2T filter part also has the same effect as the B and G filter parts. The positive and negative charges remain in balance depending on the exposure fFr The superimposed state is a state in which image exposure is performed by the exposure discharger 6.

In this state of the photoreceptor 4, a primary latent image is formed which does not function as an electrostatic latent image indicating a surface potential pattern.

This primary latent image forming surface is entirely exposed to light that passes through only one of the T, B, G, and H filter portions.

Figure 10 [3] shows this first full-surface exposure using ultraviolet light.
Uniform exposure device 7 using filter FUv that transmits only
An example of using UV light is shown. When the entire surface of the primary latent image formation surface is exposed to ultraviolet light LUv, the ultraviolet light LUv passes through only the T filter portion and is exposed to the photoconductive WJ below.
2 is conductive, and as a result, the charge at the upper and lower interfaces of the photoconductive layer 2 in that part is neutralized, and as a result, a potential appears in the dark region on the surface of the insulating surface layer 3 in the T filter part, and the bright region At P, the fli level becomes approximately 1-, and a potential pattern is generated that provides a black image of the primary latent image, as shown by the solid line in the graph below. Here, since the B, G, and R filter portions do not transmit the ultraviolet light LUv, the charged state of these portions is the same as the primary latent image formation state described in [2].

The electrostatic latent image formed by the potential of the T filter portion is developed as shown in FIG. 10 [4] by a developing device 8K using negatively charged black toner TK as a developer. The black toner TK adheres only to the T filter portion that shows a potential, and does not adhere to the B, G, and R filter portions that do not show a potential. In addition, if the T filter part sufficiently transmits light in the visible light range, no potential appears in the T filter part in the bright region P, as shown by the solid line in the graph of [3] ([2] Since the electric charge is lost during the process, toner does not stick to the surface. However, if the T filter part has low transmittance in the visible light region, the bright region P
Also, a potential appears as shown by the dotted line in the graph [3] depending on the absorption rate of the T filter portion, so toner adheres depending on the magnitude of this potential. Therefore, T
Depending on the selection of the visible light transmittance of the filter section or the selection of the ultraviolet light transmittance, toner does not adhere during white image exposure, and toner slightly adheres during colored image exposure. You can also change it like this.

Through the above steps, a black toner image is formed on the surface of the photoreceptor 4, giving the black portion of the multicolor image. Then, the potential of the T filter portion decreases as seen in the graph of potential E in [4] due to the adhesion of black toner TKO. However, even if the potential decreases, it still exhibits a slight potential, and therefore, in the next development, toner of another color may adhere to this area, resulting in uneven color.

Therefore, if necessary, an exposure discharger 6
A charger 9 that performs a corona discharge similar to that shown in Fig. 10
Perform discharge as shown in 5], and lower the potential of the T filter part to which black toner TKO is attached, as shown in the graph of potential E, so as to have almost no effect on the B, G, and R filter parts. .

This step is intended to prevent the occurrence of color turbidity as described above, and may be omitted depending on the case. The exposure discharge device 6 can also be used as a charger used in this step.

The four surfaces of the photoreceptor shown in FIG. 10 [4] or [5] on which the black toner image has been formed as described above are then exposed using a uniform exposure device using, for example, a blue filter, in the same manner as shown in FIG. 10 [3].
Perform full-surface exposure to blue light. As a result, a potential that provides a complementary color image of blue among the primary latent images appears in the B filter portion (see Japanese Patent Application No. 59-83096).
This electrostatic image is developed by a developing device using yellow toner as a developer. As a result, a color-separated one-color yellow toner image is formed on the surface of the photoreceptor 4. The electric potential of the yellow toner-attached filter portion is lowered as required by the charger 9 as shown in the electric potential E graph in FIG. The entire surface of the body 4 is then exposed to green light, for example. As a result, an image potential appears in the G filter portion, so this electrostatic image is developed by a developing device using magenta toner as a developer.
Forms a magenta toner image. The potential of this image forming surface is also lowered as necessary in the same manner as before, and finally the entire surface of the image forming surface is exposed to red light. As a result, an image potential appears in the R filter portion, so the electrostatic image is developed by a developing device using cyan toner as a developer, and a cyan toner image is formed in the same manner as in Fig. 10 [4]. . However, cyan toner adheres when the amount of light to dark areas or red components is small. As a result of the above, the photoreceptor 4
A multicolor image is formed on the surface of the toner using four colors of toner without color shift or color smudging. Since the black portions of this multicolor image are expressed by the color of the black toner, the image does not appear to lack image density and gives a very clear impression. This multicolor image is transferred and fixed onto a transfer material by conventionally known means.

The multicolor image forming method of the present invention, as in the example described above,
Although it is preferable to form the black component image first because it reduces the possibility of black toner adhering to other color toner images, the present invention is not limited to this, and the formation of the color component images may be performed in any order. You may go.

Table 1 shows the changes in each filter portion of the photoreceptor in each step of the present invention described with reference to FIG. 10 in relation to the color of the original image. In the table, G] indicates an 11th-order latent image, O indicates an electrostatic latent image, ■ indicates a toner image, ↓ indicates a state in which the state in the upper column is maintained as is, and a blank indicates a state in which no image exists. ing. In addition, - in the attached toner column indicates that no toner is attached. % Y IM, C, and C indicate that yellow, magenta, cyan, and black toners are attached, respectively.

Further, () indicates the case where the absorption rate of the T filter portion is high and no toner adheres to the white image, and 0) indicates the case where it is even higher. Of course, the colors of the original image and the reproduced colors in Table 1 indicate the colors of the constituent parts of a multicolor image. Black in the reproduced color is created by an additive coloring method using black toner and three primary color toners, and the density of the reproduced multicolor image is significantly improved due to the presence of this black toner. K
Become.

The recording apparatus shown in FIG. 11 below is a recording apparatus suitable for high-speed reproduction of multicolor images by carrying out the method of the present invention during 681 rotations of a drum-shaped photosensitive member. In other words, this recording device is
The photoreceptor 4 rotates in the direction of the arrow, and the charger 5 charges its surface to a uniform potential as shown in FIG. 10 [1], and the exposure discharger 6 is placed on the charged surface as shown in FIG. 10 [2]. As mentioned above, corona discharge and image exposure are performed to form a primary latent image,
A uniform exposure device 7U'V using an ultraviolet filter FUV exposes the entire surface of the primary latent image formation surface with ultraviolet light LUV to form an electrostatic image as shown in FIG. 10 [3]. The developing device 8K develops the latent image with black toner as shown in FIG. 10 [4], and the charger 9 changes the potential of the developed surface to
As shown in Figure [5], uniform exposure device 7B uses a blue filter FB on the development surface whose potential has been smoothed.
performs full-surface exposure with blue light to form an electrostatic image based on the potential of the B filter portion of the photoreceptor 4, the developing device 8Y develops the electrostatic image with yellow toner, and the potential of the developed surface is transferred to the charger 9. is smoothed in the same manner as in FIG. 10 [5], and a green filter F is applied to the developing surface whose potential has been smoothed. A uniform exposure device 7G using green light exposes the entire surface of the photoreceptor 4.
An electrostatic image is formed by the potential of the G filter portion of , the developing device 8M develops the electrostatic image with magenta toner, the charger 9 smoothes the potential of the developing surface, and the potential is smoothed. Uniform exposure system using red filter FR on the surface [7
R performs full-surface exposure with red light to form an electrostatic image based on the potential of the R filter portion of the photoconductor 4, and the developing device 8C develops the electrostatic image with cyan toner to form four colors on the photoconductor 4. A multicolor image is formed by overlapping toner images. The formed multicolor image is then transferred to the recording paper supply device 1.
The transferred recording paper P is separated from the photoreceptor 4 by the separator 12, and is sent to the fixing device 14 by the conveyance means 13, where it is transferred to the recording paper P fed from 0. The multicolor image is fixed and ejected outside the machine. The cleaning device 15 removes residual toner from the surface of the photoreceptor 4 to which the multicolor image has been transferred, and the photoreceptor 4 returns to a state where a multicolor image can be formed again.

The recording apparatus that implements the method of the present invention is not limited to the above-mentioned recording apparatus suitable for high speed, but may be one in which the photoreceptor 4 rotates or reciprocates by a number of times such as 8C to the developing device 8. It's okay. In such an apparatus, it is also possible to utilize a single uniform exposure device in which the entire surface exposure for each color is performed by switching filters for each color.

In the developing device 8 in the recording apparatus as described above, ~80
For example, a magnetic brush developing device as shown in FIG. 12 is preferably used. In the developing device shown in FIG. 12, the developing sleeve 81 rotates to the left or stands still, and the magnet body 82 having N and S magnetic poles on the inner peripheral surface of the developing sleeve 81 stands still or rotates in the direction of the arrow. The developer that is attracted to the surface of the developing sleeve 810 from the developer reservoir 83 by magnetic force is conveyed in the direction of the arrow by the rotation of either or both of the developing sleeve 81 and the magnet body 82;
During the conveyance, the layer thickness is regulated by the layer thickness regulating blade 84 to form a developer layer. The electrostatic latent image on the body 4 is developed.

During development, a developing bias voltage is applied to the developing sleeve 81 by a bias power supply 80, and if necessary, even when development is not performed, the bias power supply 80 is applied to prevent toner from being transferred from the developing sleeve 81 to the photoconductor 4, A voltage is applied to the developing sleeve 81 to prevent the toner from migrating to the developing sleeve 81. 85 is a cleaning blade that removes the developer layer that has passed through the developing area from the developing sleeve 81 and returns it to the developer reservoir 83; 86 is a cleaning blade that agitates and homogenizes the developer in the developer reservoir 83, and also triboelectrically charges the toner. The stirring means 88 is a toner supply roller that supplies toner from the toner hopper 87 to the developer reservoir 83. Such a developing device may be used under the condition that the developer layer on the developing sleeve 81, that is, the magnetic brush, rubs against the surface of the photoreceptor 40, but especially after the second development in the method of the present invention, In order to avoid damage to the toner image formed during development, the gap between the photoreceptor 4 and the developing sleeve 81 is wider than the thickness of the developer layer up to the developing area regulated by the layer thickness regulating blade 84 (developing Under the condition that there is no potential difference between the sleeve 81 and the photoreceptor 4), non-contact development conditions in which the magnetic brush does not rub the surface of the photoreceptor 4, such as U.S. Pat. ．． Specification No. 893,418, % Japanese Patent Publication No. 18656/1983, especially Japanese Patent Application No. 58/5744
No. 6, % Application No. 58-238295, Patent Application No. 1987-23
It is preferable to use the conditions as described in each specification of No. 8296. It uses a one-component or two-component developer containing non-magnetic toner that allows you to freely choose the coloring.
This is a developing method in which an alternating electric field is formed in a developing area to cause toner to fly from the developer layer and transfer to the photoreceptor without bringing the photoreceptor and developer layer into contact.

As the developer, either a one-component developer consisting of magnetic or non-magnetic toner or a two-component developer consisting of a mixture of toner and a magnetic carrier such as iron powder can be used. The toner is made using known techniques, and is made from known binding resins, organic and inorganic pigments, various chromatic and achromatic colorants such as dyes, and various magnetic additives that are normally used in toners. A toner with an electrostatic image development layer can be used, and carriers include iron powder, ferrite powder, which are usually used for electrostatic images, those suitable for coating with resin, or those with magnetic material dispersed in resin. Various known carriers such as magnetic carriers can be used.

In addition, the applicant filed the patent application No. 58-24966 earlier.
The developing methods described in the specifications of No. 9 and No. 240066 may be used.

Next, more specific examples of the present invention will be shown.

Example 1 The photoreceptor 4 in the recording apparatus shown in FIG.
As shown in the figure, the diameter is 30 μm with the filter part as the ground.
circular B, G, and R filter portions arranged with a 5 μm gap and an insulating layer with a thickness of 20 μm; an outer diameter of 180 mm.
It was assumed that it rotated at a surface speed of 200 m/1960 at 1R. The developing device shown in FIG. 12 was used as the developing device ii8 to 8C. The developing sleeve 81 is made of non-magnetic stainless steel, has an outer diameter of 30 m, and has a surface speed of 150 during development.
Rotate in the direction of the arrow at m/sec. The magnet body 82 is N
, the number of S magnetic poles is 8, and the maximum number of magnetic poles is 80 on the surface of the developing sleeve 810.
Provide a magnetic flux density of 0 G and 300 rpm during development.
to rotate in the direction of the arrow. Photoreceptor 4 and developing sleeve 810
The surface gap is equal to 0.7 in each developing device 8 ~ 80
5 cod, and a developer layer having a thickness of 0.4 mm was formed on the developing sleeve 81. The developer has an average particle size of 10μ
-10~20μC/? A toner that is triboelectrically charged and a carrier made of a resin containing a dispersed magnetic material having an average particle diameter of 25 μm and a resistivity of 10152 cm or more were mixed at a weight ratio of 1:4. The toner colors are black, yellow, and magenta in each developing device 8 to 8C.

Of course, it is different from cyan. A corotron discharger was used as the charger 5, and a scorotron discharger was used as the discharger of the exposure discharger 6 and the charger 9. and,
The charger 5 has a uniform surface potential of 1.5 kV on the photoreceptor 4.
A discharge voltage is applied such that the surface potential of the photoreceptor becomes uniformly -200 to
A discharge voltage such as v was applied. Also,
When ~8G is applied to the developing device 8, a DC voltage of 150V (7) and an effective value of 1.0 are applied to the developing sleeve 81.
kV.

A development bias voltage consisting of a superposition of alternating current voltages with a frequency of 2 kHz was applied.

When a multicolor image was formed under the above conditions as described with reference to FIG. 10 and recorded on the recording paper P, the recorded image obtained showed no color shift at all, the colors were insignificant, and the contrast was poor. The image quality was high and the sharpness seen in high image density was excellent.

In the above-mentioned embodiment, the T-filter part has a property of transmitting at least the ultraviolet light region and the visible light region. It is also possible to use a filter part that has the characteristic of transmitting the external light region and the refining light region (of course, it may also transmit ultraviolet light), and to perform full-surface exposure with infrared light in order to perform black development. good.

〔Effect of the invention〕

According to the method of the present invention, since each color component image is superimposed and formed using one image exposure, there is no risk of color misregistration, and each color component image contains a black toner image. , the black toner image compensates for the lack of image density due to the additive coloring method, and a clear multicolor image with excellent contrast can be reproduced.

The present invention is not limited to color copying machines, but can be widely used in various multicolor image recording devices, color photo printers, and the like. Furthermore, as already mentioned, the color of the separation filter and the combination of the corresponding toner colors can be arbitrarily selected depending on the purpose, and the photoreceptor is not limited to the shape of a drum or belt. Of course.

[Brief explanation of the drawing]

1 to 3 are partial plan views showing examples of the distribution of filter portions in the insulating surface layer of the photoreceptor used in the present invention, and FIG. 4 is a graph showing an example of the spectral transmittance characteristics of each filter portion, and FIG. Figure 5 is a graph showing an example of the spectral transmittance characteristics of a filter portion that also transmits ultraviolet light, Figures 6 to 9 are partial cross-sectional views each schematically showing examples of the layer structure of the photoreceptor, and Figure 10 is A process diagram explaining an example of the present invention, FIG. 11 is a schematic sectional view showing an example of a recording device that implements the method of the present invention, and FIG. 12 shows an example of a developing device used in the recording device of FIG. It is a schematic sectional view. T, B, G, R... Filter portion, 1... Conductive layer, 2... Photoconductive layer, 3...
... Insulating surface layer, 4... Photoreceptor, 5... Charger, 6... Exposure discharger, 7UV,
7B, 7G, 7R---Uniform exposure device, FUv・
...Ultraviolet filter, FB...Blue filter, F
G...Green filter, FR...Red filter, LR
...Red component, L (JV...Ultraviolet light, 8K
, 8Y, 8M, 80...Developing device, TK
...Black toner, 9...Charger, 10...
Recording paper supply device, P... Recording paper, 11... Transfer device,
12...Separator, 13...Transportation means, 14
...Fixing device, 15...Cleaning device, 80.
...Bias power supply, 81...Development sleeve, 82...
- Magnet body, 83... Developer reservoir, 84... Layer thickness regulating blade, 85... Cleaning blade, 86... Stirring means, 87... Toner hopper, 88
...Toner replenishment cola. Patent Applicant Konishiroku Photo Industry Co., Ltd. Sechi/Kano No. 5 Zuzu Sei C Bamboo" Figure 7 Figure 6 Figures 1 and 1 Figure 12 β Procedure Amendment Document January 1980/V Date

Claims (1)

[Claims] 1. Charging and image exposure are applied to a photoreceptor having an insulating surface layer, a photoconductive layer, and a conductive layer forming a distribution layer of a plurality of filter portions having different spectral transmittance characteristics. A method of forming a multicolor image on a photoreceptor by performing multiple exposures of a different color on the entire surface at least each time and developing the electrostatic latent image formed thereby with different color toners. A multicolor image forming method, wherein the repeated development includes development with black toner. 2. A multicolor image forming method, characterized in that development with the black toner is performed prior to development with other color toners. 3. A multicolor image forming method, wherein the color toner is a black toner and a chromatic color.