JPS6330870A - Image forming device using photosensitive body having color separation function - Google Patents

Abstract

PURPOSE:To form a color image which is free from color shift, color turbidity, and deviation in color balance, and has reproduced faithfully an original drawing, by constituting the titled device so that an area ratio of a color separating function element is in inverse proportion to a contrast ratio of a potential pattern. CONSTITUTION:Areas of specific color separating function elements related to forma tion of potential patterns of first, second and third colors are denoted as S1, S2 and S3, respectively, and potential differences in case a specific color uniform exposure has been executed, and in case it has not been executed to an area where an image exposure of a photosensitive body has not been made incident at the time point of first, second, and third developments are denoted as V1, V2 and V3 respectively, and relations of S2=alpha(V1/V2) S1, S3=beta(V1/V3) S1, and 0.7<=alpha<=1.3, 0.7<=beta<=1.3 are satisfied. In this way, even if an adjustment of a toner image density by such a development condition as fogging and color mixture caused by the fogging are generated is not executed, lowering of an adhesion density is compensated by an adhesion area of a toner, since an area of a color separating function element part lowering its contrast is large, and color balance worsening can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus using a photoreceptor having a color separation function. After performing exposure to form a primary latent image, uniform exposure to specific light to extract a potential pattern from the primary latent image to a specific color separation functional element portion and development of the potential pattern are repeated to form a potential pattern on the photoreceptor. The present invention relates to an apparatus for forming a color image formed by combining a plurality of color toner images.

[Background of the invention]

The present inventors have previously completed various inventions regarding the image forming apparatus as described above (Japanese Patent Application Nos. 59-185440, 59-187044, and 60-229524).
. Such an image forming apparatus is capable of forming toner images of each color of color separation in -times of image exposure, so there is no color shift, and each color toner image adheres to a specific color separation functional element portion. In principle, it is possible to form a color image without color bias due to the formation order of each color toner image or color mixing due to different color toners adhering to the same area. However, in reality, the surface potential of the photoreceptor changes due to dark decay, resulting in polarization due to the order in which toner images of each color are formed and color mixing due to toners of different colors adhering to the same area. In other words, the surface potential of the photoreceptor changes due to dark decay, creating a potential pattern before uniform exposure to specific light, and
This is because the change in surface potential becomes faster as the photosensitive/dark decay of the body increases, and the potential contrast decreases over time. Another cause is that a potential pattern due to dark decay occurs at the same speed in each color separation functional element portion. Color mixing due to dark decay can be prevented by smoothing the surface potential of the photoreceptor to a potential at which toner does not adhere before uniform exposure to specific light after development. Furthermore, density changes between color toner images caused by a decrease in potential contrast formed by uniform exposure to specific light due to dark decay, etc. can be adjusted by changing development conditions. but,
If development is carried out to reproduce the highlight portions of an image, fogging and color mixing are likely to occur, and if development is attempted to reproduce the solid portions of the image, there is a problem in that the image density is significantly reduced.

[Purpose of the invention]

The present invention has been made for the purpose of providing an image forming apparatus using a photoreceptor having a color separation function that does not disrupt color balance even when there is dark decay.

[Structure of the invention]

The present invention involves forming a primary latent image by charging and imagewise exposing a photoreceptor having a distribution layer of color separation functional elements, and then extracting a potential pattern from the secondary latent image to a specific color separation functional element portion. In an apparatus for forming a color image consisting of a composite of a plurality of color toner images on a photoreceptor by repeating uniform exposure and development of the potential pattern, the first. Second. The area of the specific color separation functional element related to the formation of the potential pattern of the third color is S
t.

Sz, Ss, 1st. Second. The potential difference between when specific color uniform exposure is performed and not performed on the area where image exposure of the photoreceptor was not incident at the time of the third development is V, , V2
As V, sz=α(v+/vz)Sl, S :l=
β (Vl/V co)Sl, 0.7
An image forming apparatus using a photoreceptor having a decomposition function is characterized by satisfying the following relationships: ≦ α ≦ 1.3 ° 0.7 ≦ β ≦ 1.3. achieve.

〔Example〕

The present invention will be explained below using illustrated examples.

1 to 5 are schematic partial cross-sectional views showing examples of the layer structure of the photoreceptor used in the present invention, and FIGS. 6 to 8 respectively show the distribution shape of the color separation functional elements of the photoreceptor. A partial plan view of a distribution layer showing an example, FIG. 9 is a spectral sensitivity graph of a selenium-based photoconductive layer, and FIG. 10 is a color separation functional element B
, G, R filter example spectral transmittance graph, 11th
1 and 12 are schematic configuration diagrams showing an example of the image forming apparatus of the present invention, FIG. 13 is a process diagram of image formation, and FIG. 14 is a graph of changes in surface potential of the photoreceptor in the image forming process.
FIG. 15 is a schematic sectional view showing an example of a developing device used in the image forming apparatus of the present invention, and FIG. 16 is a spectral reflectance graph of toner.

In Figures 1 to 5, 1 is made of metal such as aluminum, iron, nickel, copper, stainless steel, or an alloy thereof, and is formed into an appropriate shape or structure as necessary, such as a cylindrical shape or an endless belt shape. The conductive member 2 is a photoconductor such as sulfur, selenium, amorphous silicon or an alloy containing sulfur, selenium, tellurium, arsenic, antimony, etc., or zinc, aluminum, antimony, bismuth, cadmium, molybdenum, etc. Inorganic photoconductors such as metal oxides, iodides, sulfides, selenides, etc., or organic photoconductors such as vinylcarbazole, anthracenephthalocyanine, trinitrofluorenone, polyvinylcarbazole, holhynylanthracene, polyvinylpyrene, etc. A photoconductive layer consisting of an organic conductive conductor dispersed in an insulating binder resin such as polyethylene, polyether, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, acrylic resin, silicone resin, fluorine resin, or epoxy resin. , or charge generation layer 2a
and a charge transfer layer 2b, and 3 is a color separation functional element for blue (B) and green (G) formed from various polymers, resins, etc. and colorants such as dyes and pigments.
, red (R), etc., is an insulating layer containing N3a, which has a distribution of color separation filters such as red (R). Generally, the sensitivity of the photoconductive layer 2 differs depending on the wavelength, as shown in FIG. 9, which shows the spectral sensitivity of a selenium-based layer. In particular, the sensitivity decreases as the wavelength becomes longer. In addition, as color separation filters B, G, and R,
A material with spectral transmittance characteristics as shown in FIG. 10 is used.

The insulating layer 3 of the photoreceptor 4 in FIGS. 1 and 5 is formed by printing an insulating material such as a resin colored with a coloring agent on the photoconductive layer 2 to form a color separation filter, respectively. formed by adhering it in a predetermined pattern,
The insulating layer 3 in the photoreceptor 4 in FIG. 2 is a filter layer 3a formed in a predetermined pattern on the surface of a transparent insulating layer formed by conventionally known means, and the insulating layer 3 in the photoreceptor 4 in FIG. The filter layer 3a is sandwiched between transparent insulating layers, and the insulating layer 3 in the photoreceptor 4 shown in FIG. 4 has the filter layer 3a on the photoconductive layer 2 side and a transparent insulating layer on the outside thereof. . These filter layers 3a
is formed by means such as printing, printing, photoresist, etc.

The insulating layer 3 may be formed by first forming an insulating film or sheet containing the filter layer 3a, and attaching or adhering it onto the photoconductive layer 2 by appropriate means.

The filter layer 3a formed by adhering a coloring agent, colored resin, etc. to the insulating layer 3 has R and G colors.

Although the shape and arrangement of minute filters such as B and the size of each filter are not particularly limited, in terms of easy pattern formation, striped distribution as shown in Fig. 6, delicate multifilter It is the seventh in terms of color image reproduction.
A mosaic distribution as shown in the figure and FIG. 8 is preferable. The arrangement direction of the B, G, R, etc. filters in such a distribution may be in any direction in the spreading direction of the photoreceptor 4, not only in a mosaic distribution but also in a stripe distribution. . That is, for example, when the photoreceptor 4 is a rotating drum-shaped photoreceptor, the length direction of the stripes may be parallel to, perpendicular to, or helical to the axis of the photoreceptor. The individual sizes of R, G, B, etc. filters are as follows:
(If it becomes too thick, the resolution and color reproducibility of the image will decrease and the image quality will deteriorate; on the other hand, if it becomes too small and the particle size is the same as or smaller than the toner particle size, other adjacent colors will Therefore, each filter portion has a length of 10 to 2 as shown by J, JG, AR, l in the figure.
Preferably, the width or size is 00 μm.

In addition to the above distribution shape, G
For example, if the number of filter arrays is greater than the number of B and R filter arrays, B is in a sea of G filters.

A distribution shape in which R filter islands are scattered is also preferable because pattern formation is relatively easy and delicate multicolor images can be reproduced.

In the image forming apparatus shown in FIGS. 11 and 12, a drum-shaped photoreceptor 4 as described above rotates in the direction of the arrow, and a color image formed by combining yellow, magenta, and cyan color toner images is formed on the photoreceptor 4. In the image forming apparatus shown in FIG. 11, the image is formed within one rotation, and in the image forming apparatus shown in FIG. 12, it is formed within three rotations. This color image formation will be explained according to the process diagram of FIG.

Although FIG. 13 shows an example in which an n-type semiconductor photoconductor such as cadmium sulfide is used for the photoconductive layer 2 of the photoreceptor 4, it is not possible to use a p-type semiconductor such as selenium. Even if this happens, the basic color image formation process remains the same, only that the positive and negative signs of the charges in the following explanation are reversed.

The photoreceptor 4 rotates in the direction of the arrow in FIGS. 11 and 12,
The charger 5 charges the surface of the photoreceptor 4 with a positive corona discharge.
As shown in Figure 3 [1], it is uniformly charged. That is,
Positive charges are generated on the surface of the insulating layer 3, and correspondingly negative charges are induced at the interface between the photoconductive layer 2 and the insulating layer 3.
The surface of the photoreceptor 4 exhibits a -like potential as seen in the potential E graph. If it is difficult to inject charges into the photoreceptor 4 during this charging, uniform irradiation with white light may also be used.

Image exposure T is applied to the surface of the charged photoreceptor 4 by an image exposure device 6.
is incident. At this time, the charger 7 simultaneously performs corona discharge of alternating current or direct current of opposite polarity to that of the charger 5. As an example, in FIG. 13 [2], the red component of the image exposure (1) or the red image exposure (2) makes the lower part of the photoconductive layer 2 conductive, so in that part, the photoconductive layer 2 is made conductive. Negative charges at the interface between 2 and the insulating layer 3 disappear. On the other hand, G,
Since the B filter portion does not transmit the red image exposure I8, the negative charge of the photoconductor N2 remains in that portion. The same applies to the other color components of image exposure (3).

In this way, a primary latent image is formed on the interface between the insulating layer 3 and the photoconductive layer 2 by the charge density corresponding to the color component of each filter. However, due to the action of the corona discharge of the charger 7,
Regardless of the amount of charge on the interface between the insulating layer 3 and the photoconductive layer 2, that is, regardless of whether image exposure is applied or not, the surface potential of the photoreceptor remains constant as shown in the graph of potential E. . This is because the charge on the surface of the photoreceptor is balanced with the charge on the boundary surface, and in this state the primary latent image does not function as an electrostatic image to which toner is attached. The image exposure device 6 may be of a reciprocating type or an original passing type in either the optical system or the document table, or may be of a transmissive type rather than an original reflecting type.

Next, the uniform exposure device 8B uniformly emits blue light onto the blowhole image forming surface. FIG. 13 [3] shows the change in potential state caused by this. That is, blue light is R,
The G filter part does not pass through, so it does not change those parts, but the B filter part passes through and makes the photoconductive layer 2 below it conductive, thereby making the upper and lower interfaces of the photoconductive layer 2 in that part conductive. The charge is neutralized, resulting in B
The filter part has a potential pattern that gives a complementary color image of blue in the previous image exposure on the surface of the insulator N3, that is, an electrostatic image is at the potential E.
It appears as shown in the graph.

This electrostatic image is developed by a developing device 9Y containing yellow toner that is negatively triboelectrically charged. FIG. 13 [4] shows the developed state. That is, yellow toner T7 is
It adheres only to the B filter portion where the potential has changed due to uniform exposure with the blue light L8, and does not adhere to the R and G filter portions where the potential has not changed. As a result, a yellow toner image is formed on the surface of the photoreceptor 4. Although the potential of the area where the yellow toner T7 is attached in the B filter area decreases somewhat due to development, it is still high as seen in the graph of potential E, so that when development is performed again next time, toner will adhere and color mixing will occur. Become.

In order to prevent the above-mentioned color mixture, a charger 10Y is installed on the surface of the photoreceptor 4 on which the yellow toner image is formed, in the image forming apparatus of Section 11, and in the image forming apparatus of FIG. The charger 7 that discharged during image exposure performs corona discharge, lowering the potential of the B filter portion and reducing the surface potential of the toner adhesion, as shown in the potential E graph in FIG. 13 [5]. Equalize the potential to a level that does not. That is, the charger 10Y shown in FIG. 11 performs the same discharge as the charger 7, and in the image forming apparatus shown in FIG. The developing device 9Y and the like disposed on the way to the position are all placed in an inoperative state so as not to damage the yellow toner image, the primary latent image, etc.

A uniform exposure device 8G uniformly applies green light LG to the surface of the photoreceptor 4 on which a yellow toner image has been formed and whose surface potential has been made uniform. As a result, Figure 13 [3]
As described above, a potential pattern appears in the G filter section this time. When this potential pattern is developed by the developing device 9M containing magenta toner, the magenta toner adheres only to the G filter portion and a magenta toner image is formed as in FIG. 13 [4]. As a result, two-color toner images are combined on the photoreceptor. Furthermore, the charger 10M of FIG. 11 is placed on this image forming surface as in FIG. 13 [5].
Or perform corona discharge using the charger 7 shown in FIG.
Equalizes the surface potential.

Subsequently, the uniform exposure device 8R uniformly applies red light LR to this image forming surface. When the image exposure I is full color, a potential pattern appears in the R filter section, so this potential pattern is transferred to the developing bag f9c that stores the cyan toner.
When developed, a cyan toner image consisting of cyan toner adhered only to the R filter portion is formed. As a result, a full-color image consisting of a combination of yellow, magenta, and cyan toner images is formed on the photoreceptor 4 without color misregistration or color mixture. In addition, when the image exposure (2) is a red image exposure I8 consisting only of red components as shown in FIG. 13 [2] as an example, if the image exposure
No potential pattern appears in the filter section, therefore,
Cyan toner does not adhere even if developed by the developing device 9C.

That is, in this case, a red image is formed by combining a yellow toner image and a magenta toner image. Similarly,
The green component of imagewise exposure or green image exposure and the blue component of imagewise exposure or blue image exposure respectively produce a green image consisting of a combination of a cyan toner image and a yellow toner image;
A blue image is formed by combining the cyan toner image and the magenta toner image.

Table 1 shows the relationship in which the colors of the original image are reproduced by the above image forming process. In Table 1, the symbol "'2" indicates that a - blowhole image is formed, the symbol "○" indicates that a potential pattern or electrostatic image is formed, the symbol "O" indicates that a toner image is formed, and the symbol rlJ indicates that an upper The state of the column remains the same,
A blank column indicates a state in which no image exists. Further, "-" in the attached toner column indicates that no toner is attached, and Y, M, and C indicate that yellow toner, magenta toner, and cyan toner are attached, respectively.

If there is no dark decay on the photoconductor 4, as is clear from the above explanation, regardless of the order in which the separated color toner images are formed, a color image that faithfully reproduces the original image without color shift or color turbidity will be produced on the photoconductor 4. is formed.

However, in reality, due to dark decay, a potential pattern will be generated even in the part of the filter that is not irradiated with the uniform exposure of the specific light. The contrast of the potential pattern may be reduced, resulting in color turbidity due to color mixture, or the color balance may be disrupted due to the order in which separated color toner images are formed. This becomes more significant as the dark decay increases. and a first one in which a three-color full-color image is formed within one rotation of the photoreceptor 4.
The image forming apparatus shown in FIG. 12, which requires three rotations, is more remarkable than the image forming apparatus shown in FIG.

In addition to smoothing the potential, it also has the effect of preventing color mixture due to dark decay. On the other hand, the decrease in toner image density due to the decrease in the contrast of the potential pattern has conventionally been adjusted by adjusting the development conditions.

However, this tends to be accompanied by problems such as fogging and resulting color mixing.

Therefore, in the image forming apparatus of the present invention, the first, the second, and the second.
The area of a specific color separation functional element related to the third potential pattern formation, that is, in the example of the image forming apparatus shown in FIG.
(The ratio of Sl, S2, and 33 is the stripe width of each color separation functional element in the striped distribution shown in FIG. 6, which is 1.
In the mosaic distribution shown in Figures 7 and 8, where the size of each microfilter is equal for each of B, G, and R, it is equal to the area ratio of one B, G, and R filter.) 1. Second. At the third development time, that is,
In the image forming apparatus shown in FIG. 1112, the developing device 9Y.

9M and 9C are the potential difference between when the area of the photoreceptor where the image exposure did not enter is subjected to uniform white exposure and when it is not applied at the time when development starts, V, , V,.

As V3, S: Sz: S3 = 1:
α(V+/Vz):β(Vl/Vyu), (However,
The area ratio of the color separation functional element is made inversely proportional to the contrast ratio of the potential pattern so that α and β are in the range of 0.7 to 1.3 and satisfy the relationship A (Company). As a result, even if the toner image density is not adjusted by developing conditions that may cause fogging or color mixing, since the area of the color separation function element where the contrast decreases is large, the adhesion density can be reduced due to the toner adhesion area. By compensating for this, it is possible to prevent the color balance from collapsing.

Note that the potential differences V, , V2 . V, is the potential difference V, , V2 . shown by double arrows in FIG. It is given by V. In FIG. 14, the primary charging curve shows the change in surface potential while the surface of the photoreceptor 4 passes through the charger 5, and the secondary charging and image exposure curve shows the charger 7 where the image exposure I is also incident. Change in surface potential while passing through the position, surface potential of the part where image exposure I was not incident when uniform exposure was not performed on the area where light was applied and 11s image exposure ■ was not incident The curve E1 shows the change in the surface potential of the area where the image exposure I was applied when uniform exposure to blue light was carried out.The curve of recharging after the first development shows the image formation in Figure 11. Changes in potential smoothing by the charger 10Y in the device and the charger 7 in the image forming device shown in FIG. 12, followed by a curve E0' of uniform exposure to green light.

EO'lEI' is the surface potential change of a portion given the same history as the curve ED, EO, and E+ of uniform exposure to blue light when development is performed by the developing device 9M, and recharging after the second development. The curve shown in Fig. 11 is the charger 10M or
The changes in the potential smoothing by the charger 7 in the figure and the subsequent changes in the surface potential of portions given the same history as the uniform red light exposure tracks Eo, Eo, and E+ are shown, respectively.

The potential difference V 1 is determined from such a history of the photoreceptor 4-.

V2. V mainly depends on the properties of the photoconductive layer 2.

For example, the 5eTe photoconductive layer shown in FIG. 9 has increased sensitivity at long wavelengths by doping Te. However, as the Te doping ratio increases to 15.20.25%, the sensitivity decreases. Although the wavelength range with good wavelength expands, the proportion of dark attenuation also increases. Further, carbon black is used as the conductive member, the charge transfer layer is made of a styryltriphenylamine compound and polycarbonate, and the charge generation layer 2a is
is azo pigment 1.0, polymethyl methacrylate 0.4
, a styryltriphenylamine compound, and a polycarbonate, each of which has an amount of 0.75 parts by weight, as the amount of the azo pigment in the charge generation layer increases, the amount of dark decay increases. Conversely, when the amount of azo pigment is reduced, the amount of dark decay decreases, but the sensitivity of the photoconductive layer decreases. As described above, the dark decay of the photoreceptor 4 is largely related to the type of photoconductive layer, so for a photoreceptor without a filter layer, V, , V2. All you have to do is find V. Further, α and β indicate that the spectral sensitivity of the photoconductive layer is not -like as shown in FIG. 9, and as shown in FIG.

This is a coefficient determined by considering the transmittance characteristics of the G and R filters or the spectral characteristics of the image exposure light, etc. If this value exceeds the range of 0.7 to 1.3, the original image must be faithfully reproduced. It is difficult to do so. This α.

For example, β can be obtained by recording solid images of yellow, magenta, and cyan toner using a photoreceptor having an insulating layer containing only one type of B, G, and R filters, respectively, and placing them on a rotating plate with various fan-shaped area ratios. It can be determined experimentally by determining the area ratio that provides a color balance by pasting the images. From the above, ■1°V2. V, the area ratio S+:Sz:S:l is 1 on the photoconductive layer having the photoconductive layer.
:α(V+/VZ):β(Vl/V:l) By forming the filter layer 3a, the image forming apparatus of the present invention can be obtained.

In the image forming apparatus shown in FIGS. 11 and 12, B of the photoreceptor 4,
Since the G and R filters have the above-mentioned area ratio, it is possible to form a color image on the photoreceptor 4 that faithfully reproduces the original image without color shift or color turbidity, and the formed color image is easily transferred by a transfer pre-processing device 11 using a corona detector and a uniform exposure device for white light or infrared light, and is transferred by a transfer device 12 onto recording paper P fed by a paper feeder. Ru. The recording paper P on which the color image has been transferred is separated from the photoreceptor 4 by the separator 13 and sent to the fixing device 15 by the conveying device 14.
The color image is fixed in the fixing device 15 and then discharged outside the machine.

Then, the cleaning device 16 removes residual toner from the surface of the photoreceptor 4 to which the color image has been transferred, and the surface returns to a state where the next image formation can be performed.

It should be noted that when recording a black and white image, the image forming apparatus illustrated in the figure is configured such that - all the exposure devices 8B and 8G are uniformly exposed on the blowhole image forming surface;
, 8R or the image forming apparatus shown in FIG. 11 performs uniform exposure using a white light or infrared light uniform exposure device 8W, thereby producing B and G images.

The potential pattern generated in the R filter portion is developed by a developing device 9 containing toner to form a black toner image. At this time, the developing device 9Y in FIG.

The chargers 9M, 9C1, 10Y, IOM, IOC and the developing devices 9Y, 9M, 9C shown in FIG. 12 are not operated during image formation. As a result, a black and white image can be recorded with the same image density and resolution as in a conventional image forming apparatus using a photoreceptor without a color separation function. In this case, the image forming apparatus in FIG.
Since a combination of a white light lamp and filters F, FG, and F similar to the B, G, and R filters of the photoreceptor 4 is used for R, for example, it is possible to save the filter F3 of the sound sampling light device 8B. It is also possible to create a potential pattern in the B, G, and R filter portions by uniform exposure using the uniform exposure device 8B with the filter F retracted. Further, the charger 10C and the uniform exposure device 8W shown in FIG. 11 are also used when a black toner image is further formed after forming a color image to add contrast to the color image.

Hereinafter, further specific examples of the present invention will be shown.

Example I.

The image forming apparatus shown in FIG. 11 was used. In the photoreceptor 4, the photoconductive layer 3 having the layer structure shown in FIG. 3 is made of a 5eTe photoconductor shown in FIG. 9 with a Te doping amount of 15%, and the filter layer 3a is made of B, G, The R filter was assumed to have the distribution shown in FIG.

The developing devices 9Y to 9 contain a mixture of toner having the configuration shown in FIG. 15 and having the spectral reflection characteristics shown in FIG. A component developer was used. The surface speed of the photoreceptor 4 in the direction of the arrow was 92x*/sec, and the time required for one rotation was 4 sec. In this case, the time required from the incident position of image exposure (3) to the developing device 9Y is 0.8 sec. Potential contrast at the time of development for a photoreceptor with a 15% S e Te photoconductive layer) Vz
was about 790 V, and the potential contrast V3 at the time of development by the developing device 9C was about 750 V. According to this, S+ : SZ : Sz in the distribution of B, G, and R filters shown in FIG. 6, that is, fB:nG
:1e is 50:53.8α when 15 is 50μm
: 56.7β. Assuming there is no dark decay in the photoreceptor, there is no problem with color balance when each filter has an equal area. In contrast, in this embodiment, the stripe width of each filter is set to Ils = 50/Jm in consideration of dark decay.
, la = 54 μm, lm = 57 μm. Further, each of the developing devices 9Y, 9M, and 9C has a gap of 0.5 m between the photoreceptor 4 and the developing sleeve 91 in FIG.
By setting the layer thickness of the developer layer, which is conveyed at a sufficient supply speed in the same direction as the rotation direction of the developing sleeve 91 by the rotation of the magnet body 92 and the direction of the arrows, to 0.2 n, the bias power supply time is maintained. Either the application of the developing bias is stopped and the developing sleeve 91 is placed in a floating state, the developing sleeve 91 is grounded, or a DC bias with a polarity opposite to that of the toner is applied, and the developing sleeve 91 and the magnet body 92 are rotated. will also be suspended.

As described with reference to FIG. 13, the above-described image forming apparatus forms a color image consisting of a combination of three-color toner images of yellow, magenta, and cyan, so that there is no color shift, no color mixture, and no bias in color balance. We were able to record color images that were faithful to the original drawings.

On the other hand, the B, G, and R filters are 'l, 'G+2R in Fig. 6.
When a color image was formed using an image forming apparatus under the same conditions except that a photoreceptor having a distribution of 50 μm was used, a color image was recorded in which the yellow component was emphasized compared to the original image.

Example 2゜Photoconductive layer 2 of photoreceptor 4 is 5eT with 25% Te doping
E photoconductor, the potential contrast VI at the first development time is approximately 900ν, the potential contrast Vz at the second development time is approximately 810v, and the potential contrast ■ at the third development time is approximately At 750V, if the area SI of the B filter related to the initial potential pattern formation is 50, then S: SZ: S3 = 50: 55.6 α: 6
0β, and the filter distribution shape in Figure 6 is set to lm=50μ.
m, j! A color image was formed and recorded under the same conditions as in Example 1 except that G=56 μm and j2R=6Q μm. As in Example 1, the obtained color image was a faithful reproduction of the original image with no color shift, no turbidity in 2 colors, and no imbalance in 1 color.

On the other hand, fB of the filter distribution shape in FIG. 6, ! ! ,.

When a color image was formed and recorded in the same manner using the same image forming apparatus except that the lR was 50 μm, the obtained color image was compared to the original image better than the one listed for comparison in Example 1. It had a stronger yellow component.

Although the first and second embodiments are about striped filters, the present invention can be similarly applied to filters having any arrangement pattern. FIGS. 7 and 8 show examples of how to arrange the filters when the area of the filters is changed in that case. In the figure, the dotted line indicates the filter size when dark decay is not considered, and the solid line indicates the filter size when dark decay is considered.

〔Effect of the invention〕

According to the image forming apparatus of the present invention, an excellent effect can be obtained in that a color image that faithfully reproduces the original image can be formed without color shift, color turbidity, or unbalanced color.

[Brief explanation of drawings]

FIGS. 1 to 5 are schematic partial sectional views showing examples of the layer structure of the photoreceptor used in the present invention, and FIGS. 6 to 8, respectively.
The figures are a partial plan view of a distribution layer showing an example of the distribution shape of color separation functional elements of a photoreceptor, Figure 9 is a spectral sensitivity graph of a selenium-based photoconductive layer, and Figure 10 is a color separation functional element B,
A spectral transmittance graph showing examples of G and R filters, FIGS. 11 and 12 are schematic configuration diagrams showing examples of the image forming apparatus of the present invention, FIG. 13 is a process diagram of image formation, and FIG. 14 is an image FIG. 15 is a schematic sectional view showing an example of a developing device used in the image forming apparatus of the present invention, and FIG. 16 is a graph of spectral reflectance of toner. DESCRIPTION OF SYMBOLS 1... Conductive member, 2... Photoconductive layer, 3...
... Insulating layer, 3a... Color separation filter layer, 4... Photoreceptor, 5, 7. IOY, IOM... Charger, 6...
Image exposure device, 8B, 8G, 8R... - Sound recording device, 9Y, 9M, 9
C, 9K...Developing device, 11...Transfer pre-processing device,
12...Transfer device, 13...Separator, 16...Cleaning device. Patent applicant: Konishi Roku Photo Industry Co., Ltd.

Claims (1)

[Claims] After forming a primary latent image by charging and imagewise exposing a photoreceptor having a distribution layer of color separation functional elements, a specific uniform exposure is performed to extract a potential pattern from the primary latent image to a specific color separation functional element portion. In an apparatus that repeatedly develops the potential pattern and forms a color image on a photoreceptor by combining a plurality of color toner images, a specific color separation related to the formation of potential patterns of the first, second, and third colors is used. The area of the functional element is S_1, S_
2, S_3, and the potential difference between when specific color uniform exposure is performed and not performed on the area where the image exposure of the photoreceptor was not incident at the time of the first, second, and third development is V_1, V
_2, V_3, S_2=α(V_1/V_2)S
_1, S_3 = β (V_1/V_3) S_1, 0.7≦
An image forming apparatus using a photoreceptor having a color separation function, characterized in that the relationships α≦1.3 and 0.7≦β≦1.3 are satisfied.