JPS63118167A - Image forming device - Google Patents

Abstract

PURPOSE:To reproduce an image with high density by arranging fine small- island-shaped parts of the same kinds among plural kinds of fine small-insland- shaped parts adjacently to one another. CONSTITUTION:An image forming device is constituted by arranging a color separating function part consisting of plural kinds of fine small-island-shaped parts corresponding to light is a specific wavelength range on the light incidence side of a photoconductive layer, and small-island-shaped parts of the same kinds among the plural kinds of small-silant-shaped parts are arranged adjacently to one another, For example, the connection direction of respective unit filters of, for example, color separation filters R, G, and B is set to 90 deg. to the moving direction of the surface of a photosensitive body, and filters of the same kinds are provided adjacently to width a half as large as one side of a square unit filter. Consequently, the image forming device is obtained which is superior in resolution and gradient and increases image density sufficiently.

Description

[Detailed description of the invention]

to form a multicolor image. This invention relates to an image forming apparatus. BACKGROUND OF THE INVENTION Many methods and devices used therefor have been proposed in the past for obtaining multicolor images using electrophotography.
In general, it can be broadly classified as follows. One method is to repeatedly form a latent image using a photoreceptor and develop it with color toner according to the number of separated colors. This is a method of layering colors in rows. Another method uses a device that has multiple photoreceptors corresponding to the number of separated colors, and simultaneously exposes each photoreceptor with a light image of each color, and the latent image formed on each photoreceptor is colored. It is developed with toner, sequentially transferred onto a transfer material, and the colors are superimposed to obtain a multicolor image. However, the first method described above has a major drawback in that it takes time to record an image, and it is extremely difficult to speed up the process, since it is necessary to repeat the process of forming and developing a plurality of latent images. In addition, the second method described above is advantageous in terms of high speed because it uses multiple photoreceptors in parallel, but it requires multiple photoreceptors, an optical system, a developing means, etc., which makes the device difficult to use. It is complicated, large, expensive, and impractical. Furthermore, both of the above methods have a major drawback in that it is difficult to align images when image formation and transfer are repeated multiple times, and color shift of images cannot be completely prevented. In order to fundamentally solve these problems, it would be possible to record a multicolor image on a single photoreceptor with a single image exposure, but a method that can effectively implement this method has not yet been developed. The reality is that there is not. In particular, no consideration has been given to the developing conditions for developing with toner of each color, and as a result, it is impossible to avoid disturbances in toner images, reductions in image density, and the like. C1 Process leading to the invention In order to fundamentally solve these problems, the present inventors first invented an apparatus that can form a multicolor image by performing a single image exposure on a photoreceptor. did. The device includes a conductive member, a photoconductive layer, a photoreceptor having a plurality of different types of filters, or a photoconductive layer consisting of a plurality of parts having different spectral sensitivity distributions, and a photoconductive layer on the photoconductive layer. A multicolor image is formed as follows using a photoreceptor having an insulating layer provided thereon. That is, by applying image exposure to the surface of the photoreceptor at the same time as charging, an image is formed by the charge density at the interface between the insulating layer and the photoconductive layer, and by exposing the entire surface of the image forming surface to specific light, the photoreceptor is A potential pattern is formed on the filter portion, and the potential pattern is developed by a developing device containing toner of a specific color, thereby forming a monochrome toner image. After potential smoothing, the entire surface is exposed to light that passes through a different filter section than the previous one, and development is performed using a developing device that stores toner of a different color than the previous one, thereby producing a second color on the photoreceptor. A toner image is formed. Thereafter, potential smoothing, full-surface exposure, and development are repeated as many times as necessary. As a result, toners of different colors adhere to each filter portion of the photoreceptor, forming a multicolor image (see Japanese Patent Application Nos. 59-83096, 59-201085, and 60-229524).
. According to this multicolor image forming apparatus, image exposure is performed once,
Moreover, since the transfer only needs to be performed once, there is no risk of color misregistration. The portions in the filter (color separation filter) and the photoconductive layer where the spectral sensitivity distributions are different from each other, that is, the color separation functional portion, are
It is formed in the pattern shown in Figure 5. However, the constituent color separation filters R (red), G (green), and B
(blue) and how they are arranged are not fixed. The case in which the color separation function part is formed by a color separation filter will be explained below, but the basic difference is also the case in which the color separation function part is formed by parts with different spectral sensitivity distributions in the photoconductive layer. There is no place. Figure 25(a) shows color separation filters R (red), G (green),
Pattern with B (blue) arranged in stripes, same figure (b)
and (C) is a pattern in which color separation filters R, G, and B are arranged in a mosaic pattern as minute islands. The color separation filters R, G, and B may be arranged in any direction in the spreading direction of the photoreceptor. That is, for example, when the photoreceptor is a rotating drum-shaped photoreceptor, the length direction of the stripes may be parallel to the axis of the photoreceptor, at right angles, or helical. If the individual size of the color separation filter is too large, the resolution and color reproducibility of the image will decrease, resulting in deterioration of the image quality.If the individual size of the color separation filter is too small, and the size is the same as or smaller than that of the toner particles, the size of the other adjacent color separation filters will deteriorate. It becomes more susceptible to the influence of colored parts, and it becomes difficult to form a filter distribution pattern. Each filter section has a length of 10 to 20 mm as indicated by l in Figure 25.
It is preferable that the width or size is 0 μm. As a result of repeated studies, the inventor of the present invention has found that the above-mentioned multicolor image forming apparatus has solved the problems of the conventional apparatus described above, but the following problems still remain. There was found. In the pattern shown in FIG. 25(a), since the R, G, and day filters are continuous in a striped pattern, a high-density image can be obtained, but the resolution cannot be increased. In the pattern of the same figure (bl, (C)), minute island-like R, G
Since the day filters are arranged in a mosaic pattern, images with high resolution and excellent 7-story coverage can be obtained.
Since each microfilter is surrounded by different types of microfilters and is isolated, the potential pattern when forming a latent image is also isolated, and as a result, an image with sufficiently high density cannot be obtained. Although the image density can be changed by adjusting the developing bias, in color separation using the mosaic filter, it is still impossible to make the image density sufficiently high even by adjusting the developing bias. In other words, if the developing bias is increased recklessly, fogging and carrier adhesion will occur.
Furthermore, the life of the photoreceptor (I/W) will be shortened. The inventor of the present invention
As a result of repeated research to solve the above-mentioned problems still remaining in the multicolor image forming apparatus according to No. 01085, the present invention has been completed. 20 Object of the Invention That is, the present invention retains the advantages of the multicolor image forming apparatus of the above-mentioned Japanese Patent Application Nos. 59-83096 and 59-201085, and has excellent resolution and gradation. The object of the present invention is to provide an image forming apparatus that can sufficiently increase image density. E1.Structure of the Invention The present invention provides an image forming apparatus in which a color separation function section consisting of a plurality of types of micro-island portions corresponding to light in a specific wavelength range is disposed on the light incident side of a photoconductive layer. The present invention relates to an image forming apparatus characterized in that, among the plurality of types of micro-island portions, micro-island portions of the same type are arranged adjacent to each other. EXAMPLES Hereinafter, examples in which the present invention is applied to a multicolor image forming photoreceptor (hereinafter simply referred to as photoreceptor) and a multicolor image forming process will be described in detail. In the following explanation, red, green, and blue filters that transmit only red light, green light, and blue light, respectively, are used as color separation filters (filters that pass only light in a specific wavelength range) in the insulating layer. Only the photoreceptor for full color reproduction used will be described, but the color of the color separation filter and the color of the toner combined therewith are not fixed to the above. The process of forming a multicolor image using the above photoreceptor will be explained with reference to FIG. The figure schematically shows the image formation process in a portion of a photoreceptor that uses an n-type (high electron mobility) photosemiconductor such as cadmium sulfide as a photoconductive layer. , cross-sectional hatching of each part is omitted. In the figure, 1 and 2 are a conductive substrate and a photoconductive layer, respectively, and 3 is a three-color separation filter R, G.
, an insulating layer containing sun. Further, the graph at the bottom of each figure shows the potential on the surface of each part of the photoreceptor. First, as shown in FIG. 19 [1], when a positive corona discharge is applied to the entire surface by the charger 4, a positive charge is generated on the surface of the insulating layer 43, and correspondingly, the photoconductive layer 2 and the insulating layer 3 are A negative charge is induced at the interface. Next, as shown in FIG. 19 [2], alternating current or negative discharge is applied by the charger 5 equipped with an exposure slit, and while erasing the charge on the surface of the insulating layer 3, a colored image is exposed, for example, a red image is exposed LR. give. The red light passes through the red filter section R of the insulating layer 3, and in order to make the photoconductive layer 2 below it conductive, the red light passes through the red filter section R of the insulating layer 3, and in this filter section, the positive charges on the insulating layer 3 are erased and the photoconductive layer 2 is absorbed. Also erases the charge of On the other hand, since red light does not pass through the green 3G and blue filter parts 3, some positive charges on the insulating layer and negative charges on the photoconductive layer 2 remain as they are. The above corresponds to the formation of a primary latent image, but at this stage, not only the red filter 9 part whose charge has been erased, but also the parts 3G and 3B where charge remains have the same potential on the surface of the insulating layer. It does not function as an electrostatic image. Although FIG. 19 [2] shows a case where the potential after charging is approximately zero, it may be charged to a negative level. Next, as shown in FIG. 19 [3], for example, when the entire surface is exposed to blue light Ls obtained by the light source 6B and the blue filter Fj, the photoconductive layer 2 below the filter that transmits the blue light becomes conductive. Therefore, part of the negative charges on the photoconductive layer 2 and the charges on the conductive substrate 1 in this area are neutralized, and a potential pattern is generated only on the surface of the filter B. No change occurs in the G and R portions that do not transmit blue light. Then, when the charge image on filter B is developed with a developer containing negatively charged yellow 1-toner TY, the toner adheres only to the insulating FFtB portion which has a potential, and development is performed (Fig. 19 [4])
). Next, in order to eliminate the potential difference that has occurred, charging is performed by the charger 15 as shown in FIG. 19 [5], and then as shown in FIG.
When the entire surface is exposed to the green light Lq as in 6], a latent image is formed in the green filter portion G as in the case of the entire surface exposure to the blue light. If this is developed with magenta toner TM as shown in FIG. 19 [7], magenta toner TM will adhere only to the filter G portion. Next, Figure 19 [8
], after charging again in the same way, as shown in Fig. 19 (9) (10
) Gives full exposure to red light L4, but red filter part R
No potential pattern is formed on the surface, and even if development is performed with cyan toner, cyan toner does not adhere. When the toner image thus obtained is transferred onto a transfer material such as copy paper and fixed, a red image due to a color mixture of yellow toner and magenta toner is reproduced on the transfer material. As for other colors, as shown in the table below, color reproduction is performed by combining the three-color separation method and three primary color toners. In this table, (2) is the state of the first stage of electrostatic image formation, ○ is the completed electrostatic image, ・ is the state where development has been performed, and ↓ is the state 4J in the upper column is maintained as it is. The blank space represents the part where no electrostatic image exists. (The following is a blank space, continued on the next page.) The above explanation is based on an example using an n-type semiconductor layer, but p-type semiconductor layers such as selenium etc. Of course, it is also possible to use a type (that is, a high hole mobility) optical semiconductor layer, and in this case, the basic process is the same except that the positive and negative signs of the charges are all reversed. - If it is difficult to inject charges during the next charging, uniform irradiation with light is also used.As is clear from the above explanation, according to this embodiment, while charging the photoreceptor for forming a multicolor image, After giving an image exposure,
The process of performing development by exposing the entire surface to light of the same color as one of the plurality of types of filters is repeated according to the number of types of filters. That is, a fine color separation filter is placed on the photoreceptor, and after image exposure (step in FIG. 19 [2]), the entire surface is exposed to specific light (FIG. 19 [3], [6],

Step [9]) is applied, a potential pattern is formed for each color portion of the color separation filter, and development is performed using toner of the corresponding color (Fig. 19 [4]).
, [7], and [10]) and repeating this process to obtain a multicolor image. Therefore, according to this process, a photoreceptor is used, in which multiple color separation filters are arranged in a fine mosaic pattern on a photosensitive layer that is sensitive to the entire visible light range, and image exposure is first applied to the entire surface of the photoreceptor. A primary latent image corresponding to the resolved image density is formed on the photosensitive layer below each filter, and then a cough-colored image is formed by fully exposing the photoreceptor to light (of the same color as the filter in this particular embodiment). A secondary latent image is formed only on the filter, and a potential pattern is formed in accordance with the light intensity of the second layer image forming process. Then, it is developed with a color toner of a color corresponding to the color of the filter, preferably a color complementary to the color that passes through the filter, and the same operation is repeated for each separated image to create a multicolor image on the photoreceptor. A multicolor image can be recorded on the transfer material at once by one transfer. FIG. 20 is a schematic diagram of an image forming section of a color copying machine suitable for carrying out the above process of this embodiment. In the figure, reference numeral 41 denotes a photosensitive drum made of a photosensitive member having the structure shown in FIG. 19, which forms a multicolor image in the following manner during one rotation in the direction of arrow a during a copying operation. While rotating the photosensitive drum 41, the light source 4A is activated as necessary.
The entire surface of the document is charged with light while being irradiated with light, and the document is exposed to light while being subjected to alternating current or corona discharge of the opposite polarity to the electrode 4 from the next electrode 5 having an exposure slit. The next layer image forming step is completed. This exposure is
A document 51 placed on the document table 49 and in close contact with the document table 49 by the document presser 50 is irradiated with light from the light source lamp 31a, and the reflected light from the document 51 is reflected by the mirror 31b.
, a lens system 31C, and a mirror 31d to form an image on the photosensitive drum 41 from the back surface of the electrode 5. Light source lamp 31
An optical system 31 is constituted by mirrors 31b, 31d, and lens system 31C. The document table 49 is configured to move in the direction of the arrow at a predetermined speed, and the optical system 31 is configured to scan and illuminate the document 51. Subsequently, the entire surface of the developing sleeve 7 of the developing device 17Y is exposed to blue light obtained by the combination of the light source 6B and the blue filter Fa for the light source, and loaded with yellow toner.
Developed with Y. Subsequently, after recharging with the charger 15, the entire surface is exposed to green light from the light source 6G and the green light source filter F, the entire surface is exposed to red light from the light source 6R1 and the red light source filter FR, and the developing device 17C loaded with cyan toner is exposed. A multicolor image is formed on the photoreceptor drum through development by the developing sleeve 7C, recharging by the charger 25, exposure to white light from the light source 6W, and development by the developing device 17K loaded with black toner. The obtained multicolor toner image is transferred by a transfer electrode 9 onto a transfer material 8 supplied by a paper feeding means 18. However, 21 is a pre-transfer charging electrode, which is a photosensitive drum 41.
separated from the transport means 19)! ll sent,
A completed multicolor copy is fixed by the fixing device 13, and is discharged outside the machine. Meanwhile, I finished the transcription! 3
The light drum 41 is irradiated with a neutralizing light as necessary to eliminate static electricity using a neutralizing electrode 11, and a cleaning device 12 equipped with a cleaning blade removes residual toner on the surface of the drum 41 before being used again. The multicolor image forming apparatus shown in FIG. 21 forms a toner image of one color with one rotation of the photoreceptor 41, and is equipped with toner images for blue, green, red, and infrared colors that can be used selectively or simultaneously. This differs from the multicolor image forming apparatus shown in FIG. 20 in that the entire surface is exposed by a lamp 6 and the charger 5 of the image exposure device 31 is used to make the surface potential of the photoreceptor 41 uniform after development. Similar to the multicolor image forming apparatus shown in FIG. 20, this multicolor image forming apparatus also performs the image forming operation described in connection with FIG. Excellent monochromatic images can be formed. For example, when forming a three-color image, the photoreceptor 41 is charged by the charger 4, image exposure is performed by the charger 5, and the entire surface of the photoreceptor 41 is exposed to blue light from the lamp 6. , the potential pattern formed thereby is transferred to the developing device 17.
Y is developed to form a yellow toner image. This toner image is stored in developer @17M, 17C117K, pre-transfer charger 2.
1. The transfer device 9, the separator 10, the cleaning device 12, and the charger 4 pass through without being affected. When the photoreceptor 41 on which the toner image has been formed reaches the position of the charger 5, it receives a corona discharge and its surface potential becomes uniform, and the entire surface is exposed to green light obtained from the lamp 6, forming a potential pattern. Ru. Next, this is the developing device 17
M is developed to form a magenta toner image. Similarly, a potential pattern is formed using red light and development is performed by the developing device 17C. If you want to obtain an even better black reproduction image, then infrared light is irradiated by the lamp 6 to form a potential pattern, Black toner is deposited by the developing device 17K, and a color toner image is obtained. Infrared light is advantageous because it passes through toner that has already adhered, so it does not interfere with the formation of the potential pattern. As the developing device used in the present invention, a developing device having a structure shown in FIG. 22 is preferably used. This developing device 17 corresponds to the developing devices 17Y, 17M, and 17G shown in FIGS. 20 and 21, and
By rotating the sleeve 7 and/or the magnetic roll 43, the developer is conveyed on the circumferential surface of the sleeve 7 in the direction of the arrow, and the developer is supplied to the development area E. The amount of charge is controlled by a charge control agent. Magnetic roll 43 is indicated by arrow A
By rotating the sleeve 7 in the direction of the arrow,
The developer is fed in the direction of the arrow. The thickness of the developer layer is regulated by a spike control blade 40 made of a magnetic material during transportation. A stirring screw 42 is provided in the developer reservoir 47 to sufficiently stir the developer reservoir, and when the toner in the developer reservoir 47 is consumed, the toner supply roller 39 rotates. , toner T is replenished from the toner hopper 38. A DC power supply 45 is provided between the sleeve 7 and the photoreceptor drum 41 to apply a developing bias, and the developer is moved in the development area E so that the developer is transferred to the photoreceptor drum 41. AC power supply 4
6 is provided in series with the DC power supply 45. RE is a protection resistance. In the above image forming process, the developer used may be either a so-called one-component developer using non-magnetic toner or magnetic toner, or a so-called two-component developer using a mixture of toner and a magnetic carrier such as iron powder. Can be done. Direct rubbing with a magnetic brush may be used for development, but especially after the second development, in order to avoid damage to the formed toner image, the developer layer on the development sleeve should not be exposed to light. It is essential to use a non-contact development method that does not rub the body surface. This non-contact method uses a one-component or two-component developer containing non-magnetic toner or magnetic toner that can be freely selected for coloring, creates an alternating electric field in the developing area, and uses an electrostatic image support (photoreceptor) to Development is performed without rubbing the layers. In repeated development using an alternating electric field as described above, it is possible to repeat development several times on a photoreceptor on which a toner image has already been formed, but if appropriate development conditions are not set, This may disturb the toner image formed on the photoconductor in the previous stage, or the toner already attached to the photoconductor may return to the developing sleeve, which is the developer conveying body, and this may cause a developer of a different color from the developer in the previous stage to be disturb. This poses a problem in that it invades the later developing device that is housed, causing color mixing. From the above considerations, it is clear that the image forming conditions for recording at a desirable temperature and without image disturbance or color mixture using a -component developer or a two-component developer are as follows: -component developer or two-component developer It has become clear that this phenomenon exists in the process used. Essentially, this development condition is essentially operating the developer layer on the development sleeve without contacting the photoreceptor. For this purpose, the gap between the image carrier and the developing sleeve must be
It is thicker than the thickness of the developer layer on the developing sleeve (provided that there is no potential difference between the two).The more desirable condition is the step of forming a latent image on the image carrier, - When developing the latent image using a component developer to form a plurality of toner images on the image bearing member, in this development process, the amplitude of the alternating current component of the developing bias is set to V^ (V), and the frequency is set to 7 (Hz), and 0.2≦VAG/(d-f)≦1.6 is satisfied, where d (m) is the gap between the image carrier and the developer transporting body that IM-feeds the developer. In addition, the process includes a step of forming a latent image on an image carrier, and developing the latent image using a developer made of a plurality of components to form a plurality of toner images on the image carrier. In the forming method, in each development step, the amplitude of the AC component of the development bias is set to V
Ac (v), the frequency is j (Hz), and the gap between the image bearing member and the developer transporting member that transports the developer is d (m■).
When, it is preferable to satisfy 0.2≦Vac/(d−f)((Vxc/d)−1500)/J≦1.0. In addition, in order to prevent uneven development due to the AC component, the frequency of the AC component is set at 200
11z or higher, and when a rotating magnetic roll is used as a means for supplying the developer to the photoreceptor drum 41, the frequency of the AC component is set to 50011z or higher in order to eliminate the influence of the alternating current component and beats caused by the rotation of the magnetic roll. It is even more desirable to do so. The image forming process according to the present invention is as exemplified above, and subsequent toner images are sequentially developed on the photoreceptor drum 41 at a constant density without destroying the toner image formed on the photoreceptor drum 41. To do this, as development is repeated, (1) use toners with a sequentially larger charge amount. ■ Gradually reduce the amplitude of the electric field strength of the AC component of the developing bias. ■ Gradually increase the frequency of the AC component of the developing bias. It is more preferable to employ these methods alone or in any combination. Toner particles with a larger amount of charge are more easily affected by the electric field. Therefore, if highly charged toner particles adhere to the photoreceptor drum 41 during initial development, these toner particles may return to the sleeve during subsequent development. Therefore, point (1) mentioned above is to prevent the toner particles from returning to the sleeve during later development by using toner particles with a small amount of charge in the initial development. This method prevents the toner particles already attached to the photoreceptor drum 41 from returning by decreasing the electric field strength sequentially (that is, as the development progresses to a later stage). Specific methods for reducing the electric field strength include a method in which the voltage of the alternating current component is gradually lowered, and a method in which the gap d between the photoreceptor drum 41 and the sleeve 7 is made wider as the developing stage progresses. In addition, the above-mentioned method (2) is a method in which the frequency of the alternating current component is gradually increased as development is repeated, thereby preventing the toner particles already attached to the photoreceptor drum 41 from returning. These ■■■ are effective even when used alone, but for example,
It is even more effective to use a combination of increasing the toner charge amount by 157th order and decreasing the alternating current bias sequentially as development is repeated. Also,
When employing the above three methods, appropriate image density or color balance can be maintained by adjusting the DC bias respectively. FIG. 15 schematically shows a cross section of a photoreceptor that can be used in the present invention. A photoconductive layer 2 is provided on a conductive member or substrate 1, and a required color separation filter such as red (R
), green (G), and blue (B) filters are laminated. The conductive substrate 1 may be made of metals such as aluminum, iron, nickel, copper, and stainless steel, or alloys thereof, and may have an appropriate shape and structure as necessary, such as a cylindrical shape or an endless belt shape. The photoconductive layer 2 is made of a photoconductive material 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, antimony, bismuth, cadmium, molybdenum, etc. Inorganic photoconductive materials such as compounds, iodides, sulfides, and selenides;
vinyl carbazole, anthracene, phthalocyanine,
trinitrofluorenone, polyvinyl carbazole,
Organic photoconductive substances such as polyvinylanthracene and polyvinylpyrene are mixed into insulating binder resins such as polyethylene, polyester, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, acrylic resin, silicone resin, fluorine resin, and epoxy resin. It can be composed of a dispersed material, a functionally separated photosensitive layer consisting of a charge generation layer and a charge transfer layer, or the like. The insulating layer 3 is made of a transparent insulating material, such as various polymers,
It can be made of resin or the like, and has a colored portion on its surface or inside that acts as a color separation filter. As shown in FIG. 15(a), the colored portion is formed by printing an insulating material colored by adding a coloring agent such as a dye or pigment having a desired color onto the photoconductive layer 2 in a predetermined pattern. Alternatively, as shown in FIG.
It can be formed by adhering it to a predetermined pattern on the iaa by means such as printing or vapor deposition. Furthermore, a photoreceptor having the structure shown in FIGS. 15(a and 15b) can be constructed by attaching a film-like insulating material on which a colored portion has been formed on the photoconductive layer. The surface of the colored part may be further covered with an insulating material 3b to have a structure as shown in FIG. 15(C) or (dl).The spectral transmittance of the color separation filter is as shown in FIG. In addition, the present applicant had previously proposed a photoreceptor (patent application filed in 1983).
-199547). For example, as shown in FIG. 17, an insulator R3c is provided on one surface of the photoconductive layer 2, and a layer 3a consisting of a transparent conductor 75161 and a color separation filter is provided on the other surface (even though the color separation filter is conductive). ) are sequentially deposited and laminated. The transparent conductive layer 101 is formed by depositing ITO, for example. In the photoreceptor having this structure, charging is performed by injecting charges from the insulating layer 30 side, and image exposure and full-surface exposure are performed from the 3/ side formed by the color separation filter. The shape and arrangement of the plurality of types of fine color separation filters constituted by the colored portions are such that unit filters of the same type are arranged adjacently. Here, the direction in which they are arranged in succession is important for preventing moire from occurring. Multicolor image (
When forming a full-color image, if the original image (original) is a printed matter, moiré may occur. Printed matter is generally printed using halftone dot printing that reproduces the density of the original as a set of large and small dots, and the direction of these halftone dots is changed for each color to prevent the occurrence of moiré patterns. On the other hand, the angle is 15° for cyan, 75° for magenta, 30° for yellow, and 45° for black. The halftone dots are also arranged in a direction that is 90° plus the above angle. Therefore, in image formation, in order to prevent the occurrence of moiré, it is necessary to ensure that the direction in which the color separation filters are arranged does not coincide with the direction described above, and it is preferable that the difference be 15 degrees or more. In particular, the occurrence of moire is most noticeable in black colors. In addition, the number of halftone dots per inch of printed matter is 150 to 175 in art printing using art paper! Nationality is 80-1oo
The newspaper puts it at 60-65. In Figure 1, the connection direction of each unit filter of color separation filters R, G, and B is set at 90 degrees with respect to the moving direction of the photoreceptor surface, and filters of the same type with a width half the negative side of the square unit filter are shown. This shows a pattern in which the two are placed adjacent to each other. The pattern shown in FIG. 2 is a pattern in which the above-mentioned angle is set at 150° and filters of the same type are provided adjacently with a width half of one side of the square unit filter. The pattern in Figure 3 is a pattern in which square unit filters are arranged vertically and horizontally like the eyes of a board, and R, G, and day unit filters are arranged diagonally adjacent to each other at corner points. It is. In this pattern, unit filters of the same type are successively arranged in a direction at an angle of 135° with respect to the moving direction of the photoreceptor. With this pattern, when forming an image consisting of two of the three colors and a white background without black, moiré will not occur. However, in full-color image formation with the addition of black, moiré will occur. Therefore, for full-color image formation, it is recommended to
The arrangement may be rotated by 5 degrees or counterclockwise by 30 to 35 degrees or 45 degrees. In the patterns shown in FIGS. 1 to 3, since the unit filters are square in shape, the patterns can be easily formed. Moreover, the size 11 of the unit filter shown in the figure is 10~
Preferably, it is 200 μm. The pattern shown in FIG. 4 is a pattern in which the shape of each unit filter of the pattern shown in FIG. 3 is rectangular, and the direction in which the unit filters of the same kind are connected is oriented at 150 degrees with respect to the moving direction of the photoreceptor. The pattern in FIG. 5 and the pattern in FIG. 6 are patterns in which each unit filter has a rectangular shape, and unit filters of the same type are adjacent to each other along most of one side in the longitudinal direction, and the pattern is a pattern in which the unit filters of the same type are adjacent to each other along most of one side in the longitudinal direction, and The direction of movement of the photoreceptor surface is 150 degrees in the pattern of FIG. 5, and 60" in the pattern of FIG. 6. In the patterns of FIGS. The length 12 of the shorter side of the unit filter shown is preferably 10 to 200 μm. The pattern in FIG. 7 and the pattern in FIG. 8 are honeycomb-like patterns in which the unit filter has a regular hexagonal shape. , are adjacent to unit filters of the same type on one side of a regular hexagon.In the pattern of Figure 7, the direction in which the unit filters of the same type are arranged is 150° with respect to the moving direction of the photoreceptor surface.
In the pattern of FIG. 8, the direction is 90°. In the patterns shown in FIGS. 7 and 8, it is preferable that the length 13 between the opposing sides shown in the figures is 10 to 200 μm. In the pattern shown in FIG. 9, G is arranged diagonally downward to the right, and R, G, diary columns and day, G, R arrangement are alternately used for each row. As a result, B and R are arranged in a stepwise manner downward to the left. In the pattern shown in FIG. 10, G is arranged in a zigzag pattern every three rows. In Fig. 11, when compared with Fig. 10, the arrangement direction of G is the same, but the arrangement directions of day and R are different, and each row has R, G,
The B array and the day, G, and R arrays are used alternately. In Fig. 12, G is arranged in vertical stripes, and each row has R,
The G, B arrangement and the day, G, R arrangement are used alternately. In Figures 9, 11, and 12, excluding Figure 10, R,
G. Diary sequence and E3. Although the G and R arrays are used alternately for each row, it is of course possible to use a cycle of two or more rows, or a mixture of cycles of one to several rows. The size of the unit filter in FIGS. 9, 10, 11, and 12 is 14, l! 5 is preferably 10 to 200 μm. Here, 14=ISO is shown, but 1
．． + and βS may have different sizes. In Figure 13, the day is horizontal, the C is diagonal downward to the right, and the R
are arranged diagonally downward to the left. The day, G, and R filters may be replaced in sequence. unit filter size i6,
! 7.18 is preferably 10 to 200 μm. In FIG. 14, triangular unit filters are used. E3. R and G are arranged in the vertical direction. Unit filter size 19, el. is 10~200μ
It is preferable to set it to m. As shown in Figures 9 to 13, the direction in which the color separation filters are connected (
Indicated by virtual lines in each figure. ) in a zigzag manner or by changing the connection direction depending on the type of color separation filter, the color separation filter section as a whole loses directionality, and the occurrence of moiré can be more reliably prevented. The patterns shown in FIGS. 1 to 14 are all patterns in which unit filters of the same type are arranged adjacently over at least the entire latent image forming area on the surface of the photoreceptor, but in addition to the above, In the pattern of FIG. 25(b) or (C), patterns such as those shown in FIGS. 1 to 14 may be dispersed and arranged at many locations. Note that it is desirable that each filter has high resistance. Additionally, a layer of color separation filters can be suitably disposed through which the photoconductive layer can be exposed. In addition to the structures shown in FIGS. 15 and 17, a photoreceptor having the structure schematically shown in FIG. 18 (al, mountain) can be used. Components having the same functions as those in FIG. 15 are designated by the same reference numerals as in FIG. 15. A photoconductive layer 2 is provided on a conductive member or substrate 1, and this photoconductive layer has a photoconductive portion 2R having a desired spectral sensitivity distribution.
12G, 2B, including a large number of photoconductive parts sensitive to red (R), green (G), and blue (day), for example. An insulating layer 3b is laminated on this photoconductive layer. The conductive substrate 1 may be made of metals such as aluminum, iron, nickel, copper, or alloys thereof, and may have an appropriate shape and structure as necessary, such as a cylindrical shape or an endless belt shape. The photoconductive layer 2 is formed to a thickness of 10 to 100 μm and is made of a photoconductive material such as sulfur, selenium, amorphous silicon, or an alloy containing sulfur, selenium, tellurium, arsenic, antimony, etc.; or zinc, aluminum, antimony, etc. Inorganic photoconductive materials such as metal oxides, iodides, sulfides, and selenides such as bismuth, cadmium, and molybdenum; organic photoconductive materials such as vinyl carbazole, anthracenephthalocyanine, trinitrofluorenone, polyvinyl carbazole, polyvinylanthracene, and polyvinylpyrene. Conductive substances dispersed in insulating binder resins such as polyethylene, polyester, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, acrylic resin, silicone resin, fluororesin, epoxy resin, etc., and charge generation and transfer. It can be constructed by a functionally separated laminate, etc., in which the functions are carried by separate layers. The insulating layer 3b is formed to have a thickness of 10 to 100 μm, and can be made of a transparent insulating material, such as various polymers and resins. The photoconductive part I'52 has colored parts 2R12G and 2, which are photoconductive parts with different spectral sensitivity distributions, but these colored parts have the required spectral sensitivity as shown in FIG. 12(a). The photoconductive material can be deposited on the conductive layer 1 in a predetermined pattern by printing or other means. Alternatively, as shown in FIG. 12(b), charges are generated ff on the charge transport Fi2a uniformly formed in advance on the conductive layer 1 or on the photosensitive layer 52a.
12b (which consists of portions having different spectral sensitivities) may be formed by being attached in a predetermined pattern by means such as printing or vapor deposition. The planar arrangement of the photoconductive portion 2R12G52 may be the same as that shown in FIGS. 1 to 14. Next, a specific example carried out with the configuration described above will be described using the apparatus shown in FIGS. 20 and 22. A recording apparatus shown in FIG. 20 was used. However, image carrier 4
1 has a structure shown in FIG. 15 (a) and FIG.
, R was provided with an insulating layer having a periodic IC of 150 μm, and its circumferential speed was 180 mm/sec. The image carrier 41 was uniformly exposed to light by the lamp 4A of the primary charger 4 and charged by the DC scorotron corona discharger 4 so that the surface potential of the image carrier 41 was +2000 V. Next, the original 51 is scanned using the optical system 31, and while image exposure is performed on the photoreceptor, the image carrier 41 is
was charged so that its surface potential was 150V. During image exposure, infrared and ultraviolet light was cut off using a filter in advance. An electrostatic image with a contrast of -50 to 300 V was then formed by full exposure through a blue filter. This potential contrast was 1/3 of that when a transparent insulating layer was used. This electrostatic image was developed in a developing device 17Y as shown in FIG.
Contains dispersed particles, average particle size is 20μm, magnetization is 30Cmu
/ g, a carrier with a resistivity of 10'qΩcm or more;
A two-component developer consisting of a nonmagnetic toner with an average particle size of 5 μm, which is made by adding 10 parts by weight of a benzidine derivative as a yellow pigment to a styrene-acrylic resin and other charge control agents, has a toner to carrier ratio of 20 wt%. It was used under the following conditions. Further, the outer diameter of the developing sleeve 7 is 3 (hm,
The rotation speed is 1100 rp, the magnetic flux density of the N and S magnetic poles of the magnet body 43 is 900 Gauss, and the rotation speed is 11000 rp.
The thickness of the developer layer in the development area is 0.2 NM. The gap between the developing sleeve 7 and the image carrier 41 is 0.5 mm, and the developing sleeve 7 is supplied with a DC voltage of +150■ and 1.5 k.
The non-contact development conditions were such that a superimposed voltage of an alternating current voltage of 1000 V (the amplitude of the method wave is I'rxtooov) was applied. Incidentally, while the electrostatic image was being developed by the developing device 17Y, the other developing devices 17M and 17C, also shown in FIG. 22, were kept in a non-developing state. That is, disconnecting the developing sleeve from the power source 45, 46 and leaving it in a floating state, or grounding it.
Alternatively, this can be achieved by positively applying an electrostatic DC bias voltage of the same polarity as the image (that is, opposite polarity to the toner charging) to the developing sleeve, and it is particularly preferable to apply a DC bias voltage. In addition, the driving of the developing device was stopped during non-developing time. Developer units 17M and 17C are also developer unit 17.
Since development is performed under the same non-contact development conditions as Y, the developer layer on the development sleeve does not need to be removed. This developing device 17M uses a developer in which the toner in the developing device 17Y is changed to a toner containing polytungstophosphoric acid as a magenta pigment instead of a yellow pigment, and the developing device 17C uses the same ( A developer was used in which the toner was changed to a toner containing a copper phthalocyanine derivative as a cyan pigment, and a toner containing carbon black was used in the developing device 17K.The spectral reflectance of each toner was as follows: As shown in the figure.Of course, color toners made of other pigments or dyes can also be used, and the order of developing colors can be appropriately determined so as to obtain clear color images.Especially The order in which the colors are developed needs to be carefully determined as it may be related to the sharpness of the color image and the potential contrast obtained. After recharging the surface potential to -60V using a corona charger, the entire surface was exposed through a green filter.The position of the electrostatic image obtained was as follows:
It was +300V compared to 0V. This electrostatic image
DC component +50V, AC component 2.5kHz to developing sleeve
z, developing device 17Y except that a voltage of 2000 V was applied.
The film was developed using the developing device 17M under the same conditions as in . After being similarly recharged to a surface potential of 70 V using a scorotron charger, the entire surface was exposed through a left filter. As a result, +250■ for the background part -70V
An electrostatic image is formed on the developing sleeve with a DC component of +20V and an AC component of 2.5 kHz, 2000V.
Developing was carried out in the developing device 17C under the same conditions as in the developing device 17Y, except that a voltage of 1 was applied. After similarly recharging the surface potential to 180 V using a scorotron charger, white light was irradiated and the entire surface was exposed. As a result, an electrostatic image of +230 V is formed against the background area of -80 V, and this electrostatic image is transferred to the developing sleeve with a DC component of +IO.
Developing was carried out in the developing unit 17K under the same conditions as in the developing unit 17Y, except that a voltage of 2,000 V and an AC component of 3.0 kHz was applied. When this fourth development is performed and a three-color image and a black image are formed on the image carrier 41, the corona discharger 21 and the pre-transfer lamp 22 are activated, thereby causing the color The image was made easily transferable and was transferred onto a transfer material 8 by a transfer device 9, separated by a separator 10, and fixed by a fixed heat roller fixer 13. The image carrier 41 to which the color image has been transferred is subjected to static electricity removal by the static eliminator 11 while being irradiated with white light.
The remaining toner was removed from the surface by the cleaning blade 2, and one cycle of color image recording was completely completed when the surface on which the color image was formed passed through the cleaning device 12. The density of the original image (original) and the full-color image (copy) obtained as described above was measured for each color using a reflective density needle, and the results are shown in FIG. 2. For comparison, the same figure also shows the results of similar image formation using a layer made of color separation filters having the pattern shown in FIG. 25(b) in broken lines. The image according to this example has a higher density for each color than the comparative image, is approximately the same as the density of the original image, has the same resolution and gradation as the original image, and has no color shift or color turbidity. Furthermore, the occurrence of moiré was not discernible to the naked eye, but could only be discerned using a looper, and the image was of high quality and faithful to the original image. Further, the pattern shown in FIG. 11 was adopted as the arrangement of the color separation filters (however, 14 and eS were both 50 μm), and image formation was performed under the same conditions as above. The obtained image was of high quality and faithful to the original image, as in the above example, and no moiré was observed. The reason why moiré can be prevented so reliably is that the unit filters are arranged so that the color separation filter section as a whole has no directionality, as described above. The results of image formation by the multicolor image forming apparatus shown in FIG. 21 are also as follows.
The results were similar to those above. The reason why high-density images can be obtained by using a color separation function section in which unit filters of the same type are arranged adjacently as shown in Figures 1 to 14 is as follows. considered to be a thing. % 25 ff1 Like the patterns of (b) and (c),
In a pattern in which a unit filter is isolated surrounded by different types of unit filters, the potential pattern of the latent image of each color is also formed isolated in a narrow area, and therefore the electric field between the filter and the developing electrode (developing sleeve) is The image density also becomes smaller and the image density becomes lower. On the other hand, when unit filters of the same type are placed adjacent to each other, as in the pattern in Figure 2 (the patterns in Figures 2 to 14 are similar), the potential pattern is also formed over a wide area, so the filter The electric field between the photoreceptor and the developing electrode also becomes thicker (and as a result, the image density also increases. Development is not limited to the above-mentioned development method, but as a modified example of a development method that is performed without sliding the photoreceptor, A method in which only the toner is taken out from a composite developer onto a developer transport carrier and one-component development is performed using lunar in an alternating electric field (Japanese Patent Laid-Open No. 59-42565, Japanese Patent Application No. 58-231434)
, a method of developing with a one-component developer in an alternating electric field by providing a linear or rope-shaped control electrode (Japanese Patent Laid-Open No. 56-125
No. 753), a method in which a similar control bridge is installed and development is carried out using a two-component developer in an alternating electric field (Japanese Patent Application No. 58-979)
Needless to say, the method (No. 73) is also included in the multicolor image forming method according to the present invention. In the above embodiments, corona transfer is used as the toner image transfer method, but other methods may also be used. For example, Japanese Patent Publication No. 46-41679, No. 48-
When the adhesive transfer method described in Japanese Patent No. 22763 is used, transfer can be performed without considering the polarity of the toner. In addition, the layer structure of the photoreceptor can be made transparent by providing a transparent insulating layer, a photoreceptor layer, a conductive layer, and a filter to provide primary and secondary charging from the transparent insulating layer side, image exposure from the filter side, and overall exposure. A configuration may also be adopted in which development is performed from the insulating layer side. In addition, all of the above explanations have been made regarding examples of color copying machines that use so-called three-color separation filters and three primary color toners, but the embodiments of the present invention are not limited to this, and can be applied to various multi-color image recording devices. Can be widely used in color photo printers, etc. It goes without saying that the combination of the color of the separation filter and the color of the toner corresponding thereto can be arbitrarily selected depending on the purpose. For example, a process to obtain a two-color copy may be considered;
A filter in which the filters are continuously distributed can be used, and the original can be made up of two colors, a red part and a black part. In this case, if you use basically the same process as above (however, the entire surface exposure is done with G and R1 or G and day),
As a copy, for the black part of the original f^, a nearly black copy part consisting of black toner and red toner is obtained,
There is a process for obtaining a red part made of red toner for the red part of an original. Therefore, in this specification, the term "multiple types of filters" refers to a photoreceptor that has a layer consisting of a portion (which may be transparent resin, air, etc.) that does not have a single type of color filter. Since the part without this filter can be regarded as a transparent filter, such cases are also included. Note that the term "electrification" as used herein includes cases where the surface potential becomes 0 or the surface charge disappears when "charging" is performed. In addition, in the above explanation, the spectral characteristics of the specific light for full-surface exposure are those of the same color as the filters of the photoreceptor, green (G), blue (B), and red (R), but the spectral characteristics is not something that jumps to G, Japan, and R. In short, any spectral characteristic is sufficient as long as it forms a potential pattern only on a specific filter section (not necessarily constant) corresponding to specific light on the photoreceptor by full-surface exposure to specific light.For example, if a potential pattern is formed on a blue filter For example, when a pattern is formed, the entire surface is exposed using a material having broad spectral characteristics including wavelengths of approximately 500 nm or less and 400 nm or less. As described in detail in Section 1, the present invention has the following effects. (1) Equipped with a color separation function section consisting of multiple types of micro-island-shaped parts that correspond to light in a specific wavelength range, it is possible to form a latent image with a single image exposure, resulting in color shift and color turbidity. It is possible to easily form images without (2) Among the plurality of types of micro-island portions, the micro-island portions of the same type are arranged adjacent to each other;
A potential pattern of latent image is formed continuously for each color, 71$
The electric field in the l', It development area also becomes stronger, and as a result, a high-density image is reproduced.

[Brief explanation of the drawing]

1 to 24 show embodiments of the present invention, and FIG. 1, FIG. 2, FIG. 3, FIG. Figures 9, 10, 11, 12, 13, and 14 are enlarged plan views showing the arrangement of color separation filters, and Figures 15 (a), (b), and (C1 and (d
) is an enlarged sectional view of the photoreceptor, FIG. 16 is a graph showing the spectral transmittance of the color separation filter, FIGS. 17 and 18 (a) and (b) are enlarged sectional views of other photoreceptors, respectively. Figure 19 [1], [2], [3], [4], [5], [
6], [7], [8],

[9] and [10] are process flow diagrams showing the image forming process, Figures 20 and 21 are schematic diagrams of a multicolor image forming apparatus, Figure 22 is a cross-sectional view of the developing device, and Figure 23 is a toner FIG. 24 is a graph showing the relationship between the density of the original image and the density of the reproduced image (copy). In addition, in the symbols shown in the drawings, 1... Conductive substrate 2... Photoconductive layer 3... Color separation filter. Insulating stone including 4.
......-Flying charger 5...Secondary charger 7.7Y, 7M, 7G, 7K...Development sleeve 8...・・・・・・Transfer material 15.16・・・・・・Recharger 17, 17Y,
17M, 17C, 17K...Developer 31...Optical system 41...Photosensitive drum (image carrier) 51
......Original image (manuscript) R...
...Red filter G in the color separation function section...
...Green filter B in the color separation function section...
...Blue filter 2B in the color separation function section...
...Blue light-sensitive photoconductive section 2R in the color separation function section.... Red light-sensitive photoconductive section 2G in the color separation function section... Color separation function section Inside green light sensitive photoconductive part Fs......Blue filter F (......Green filter FR.......Red filter R... ...The red component of the image exposure light...
・・・・・・Red light LB・・・・・・Blue light L9・・・・・・Green light TY・・・・・・Yellow toner TM・・・・・・
. . . Magenta toner O . . . Developer T . . . Toner.

Claims (1)

[Claims] 1. In an image forming apparatus in which a color separation function section consisting of a plurality of types of micro-island-shaped parts corresponding to light in a specific wavelength range is disposed on the light incident side of the photoconductive layer, the plurality of micro-island-shaped parts of the plurality of types An image forming apparatus characterized in that the image forming apparatus includes a structure in which micro island-shaped parts of the same type are arranged adjacent to each other.