JPS6391677A - Copying machine using photosensitive body with color separating function - Google Patents

Abstract

PURPOSE:To record a color image which faithfully reproduces the image of an original by providing an original image reading means detecting the image density of the original on an original platen by color and automatically deciding on development conditions in a color image forming step according to information from the reading means. CONSTITUTION:The original image reading means 13 is provided which detects the image density of the original on the original platen 5 by color. According to the information from the reading means 13, development condition in the color image forming step are automatically decided. Namely, a CPU produces a color-by-color density histogram from information outputted from a color image sensor, judges a line picture,a photograph and an ordinary picture in which a line picture and a photograph are mixed, and sets development conditions according to the judgement. Thus, even a layman easily records a high reproducibility transferred image fitting to the line picture of the original, an ordinary picture or a photograph.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a copying machine using a photoreceptor having a color separation function.

[Background of the invention]

The above-mentioned copying machine charges a photoreceptor and imagewise exposes it to form a primary latent image, and then uniformly exposes the photoreceptor to a specific light that produces a potential pattern in a specific color separation functional area from the next layer image. By repeating development with a specific color toner of a potential pattern,
Since a color image is formed on a photoreceptor by combining toner images of each color separated, it has the advantage of being able to reproduce color images without color turbidity due to color shift or color mixture.

However, on the other hand, it is difficult to faithfully reproduce high-density areas for images with clear contrast, such as line drawings and graphics in manuscripts, and to faithfully reproduce halftone areas for tonal gradations such as photographic images. Even if there is a general demand that it is desirable, there is a problem in that it is not easy to respond to it. The reason for this is that the potential pattern of each color separation, that is, the electrostatic image developed with toner, is extracted from the primary latent image formed by the image exposure of - times, so the formation of the electrostatic image of each color separation can be controlled independently. ■ The potential contrast of each color separation electrostatic image changes because the spectral sensitivity of each color separation functional part differs; ■ The potential contrast of the electrostatic image developed later decreases due to dark decay; ■ This is because the fatigue of the photoreceptor may vary depending on the color separation functional portion, and thus an electrostatic image cannot be formed to satisfy the above-mentioned requirements.

Therefore, the present inventors first completed an invention for a copying machine in which the above-mentioned problem was solved by changing the developing bias applied to the developer conveying sleeve of the developing device (Japanese Patent Application No. 60-258774 issue).

With this copier, by selecting and pressing the density/gradation button on the operation panel, you can record a color image that faithfully reproduces high-density areas or a color image that faithfully reproduces halftone areas. . However, such selection can be quite troublesome for those who are not familiar with copying machine operations, and may result in incorrect selections being made or forgetting to make a selection, resulting in line drawings with low density being recorded, or lines with high contrast being recorded. It is easy to record images with too many gradations.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and each development condition is automatically determined depending on whether the image of the original is a high-contrast image, a gradation image, etc.
An object of the present invention is to provide a copying machine using a photoreceptor having a color separation function capable of recording a color image that faithfully reproduces an original image.

[Structure of the invention]

In the present invention, after charging a photoreceptor having a color separation function and exposing the original to light using light, uniform exposure to a specific light and development using a specific color toner are repeated to create a plurality of toner images. A copying machine that forms a composite color image is provided with a document image reading device that detects the image density of the document on the document table for each color, and automatically adjusts each development condition in the color image forming step based on information from the reading device. The above object is achieved by this configuration.

〔Example〕

The present invention will be explained below using illustrated examples.

1 to 4 are partial cross-sectional views schematically showing examples of the layer structure of a photoconductor used in the copying machine of the present invention, and FIGS. 5 to 7 are distributions of color separation functional elements of the photoconductor, respectively. FIG. 8 is a schematic configuration diagram showing an example of the copying machine of the present invention, FIG. 9 is a partial plan view showing an example of the operation panel of the copying machine of the present invention, and FIG. 10 is a color image. An explanatory diagram of the forming process, FIG. 11 is a schematic configuration diagram showing an example of a developing device used in the copying machine of the present invention, and FIGS. 12 and 13 are diagrams showing the case where the voltage and frequency of the AC component of the developing bias are changed, respectively. A graph showing the relationship between electrostatic image potential and recorded image density. FIG. 14 is a partial plan view of the document table showing an example in which the document image reading means scans the document. FIGS. 15 and 16 are reading diagrams of the document image reading means. A partial sectional view and a partial plan view showing the configuration of the parts, FIG. 17 is a density histogram for each color obtained by processing information of the document image reading means, and FIG. 18 is a configuration showing another example of the copying machine of the present invention. The schematic diagram, FIG. 19, is a sectional view showing an example of a specific light type exposure device used in the copying machine shown in FIG. 18.

The photoreceptor shown in FIGS. 1 to 4 is made of aluminum.

On the electric shock base 1, which is made of metal such as iron, nickel, W4, etc. or an alloy thereof, and is formed into an appropriate shape and structure as necessary, such as a cylindrical shape or an endless belt shape, and is used as a ground electrode,
Photoconductors such as sulfur, selenium, amorphous silicon or alloys containing sulfur, selenium, tellurium, arsenic, antimony, etc., or zinc.

Inorganic photoconductors such as oxides, iodides, sulfides, and selenides of metals such as aluminum, antimony, bismuth, cadmium, and molybdenum, or vinyl carbazole,
Anthracenephthalocyanine.

trinitrofluorenone, polyvinyl carbazole,
Organic photoconductive materials such as polyvinylanthracene, polyvinylpyrene, polyethylene, polyester, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, acrylic resin, silicone resin, fluororesin.

A photoconductive layer 2 consisting of an organic photoconductor dispersed in an insulating binder resin such as an epoxy resin, or a functionally separated photoconductive layer 2 consisting of a charge generation layer and a charge transfer layer is provided, and a color separation function is provided thereon. The elements blue (B), green (G), red (R
), etc., is provided with a light-transmitting insulating layer 3 including a filter distribution layer 3a. The photoreceptor in Fig. 1 is
An insulating material such as a resin colored by adding a coloring agent such as a pigment or dye to form a color separation filter is directly applied to the electrical layer 2 by means such as printing, vapor deposition, or photoresist. The photoreceptor of FIG. 2, in which the insulating layer 3 consisting of the filter distribution layer 3a is formed by depositing it in the pattern shown in FIG. 7, has a conventional color separation function on the photoconductive layer 2. Similar to the photoconductor with a three-layer structure, a transparent insulating layer 3b is formed, and a filter distribution layer 3a is formed thereon, similar to the photoconductor shown in FIG. Distributed layer 3a (!: i7i bright insulating layer 3b
It consists of The photoreceptor shown in FIG. 3 can be obtained by further providing a transparent insulating layer 3C on the photoreceptor shown in FIG. The photoconductive layer 2 is obtained by attaching the film to the photoconductive layer 2 using a transparent insulating adhesive or pressure-sensitive adhesive, and the latter method is inexpensive.

In this case, the transparent insulating layer 3C serves as a protective layer for preventing the filter distribution N3a from deteriorating due to ozone or the like generated during the image forming process.

In addition, the transparent insulating layer 3b in the photoreceptor in FIGS. 2 and 3
is an adhesive layer for the photoconductive layer N2 of the insulating layer N3. The photoreceptor shown in FIG. 4 has a transparent insulating layer 3C as a protective layer provided on the photoreceptor shown in FIG. 1. Figures 2 and 4
When the photoreceptor in the figure is cylindrical, it also includes one in which a film provided with a filter distribution layer 3 is wound around the photoconductive layer 2 and fixed by mechanical means;
can be easily replaced.

Although the shape and arrangement of the B, G, and R filters in filter distribution F3a are not particularly limited, a striped distribution as shown in FIG. 5 is preferred because it facilitates pattern formation, and delicate multicolor A mosaic distribution as shown in FIGS. 6 and 7 is preferable in terms of image reproduction.

The direction in which the filters and the like are arranged may be in any direction in the spreading direction of the photoreceptor, not only in a mosaic distribution but also in a stripe distribution. That is, for example, in the case of a rotating drum-shaped photoreceptor, whether the length direction of the stripe is parallel or perpendicular to the axis of the photoreceptor,
Alternatively, it may be helical. If the individual size of filters etc. becomes too large, the resolution and color reproducibility of the image will decrease, resulting in deterioration of the image quality.On the other hand, if the individual size of the filter etc. becomes too small, it will be the same as or smaller than the particle size of the toner particles. , it becomes easier to be influenced by other adjacent color parts, and it becomes difficult to form a filter distribution pattern. Therefore, the size is as shown! It is preferable that the width or size is such that the length shown by is 10 to 500 μm.

The copying machine shown in FIG. 8 uses the drum-shaped photoreceptor 4 as described above. In this copy hall, copies are made as described below.

First, a case will be described in which a color image is copied by specifying whether it is a line drawing, a photographic drawing, or a general image that includes both. First, as an operation common to other cases, place the document 0 on the glass plate 5a of the document table 5 as shown in FIG. 14, close the document table cover (not shown), and press the operation panel shown in FIG. The user specifies the number of copies using the copy number designation button 6, and appropriately moves the Y, M, C, or even K shade adjustment slide buttons as necessary. Is it a line drawing or a photographic drawing?
If you want to specify whether it is general, press the button for line drawing, general, or photo, respectively. When you want to obtain a color image, do not press the single color specification button. Then press the copy start button. As a result, the photoreceptor 4 rotates in the direction of the arrow in FIG.
Charge as shown in Figure 0 [1]. In the 10th article, an example in which an n-type semiconductor photoconductor such as cadmium sulfide is used for the photoconductive layer 2 of the photoreceptor, and therefore the corona discharge of the charger 7 is made a positive corona discharge. However, if a p-type photoconductor such as selenium is used for the photoconductive N2, the image forming process in the following explanation will basically change except that the positive and negative polarities of charging etc. will be reversed. do not have.

FIG. 10 [1] shows that a positive charge is given to the surface of the insulating layer 3 of the photoreceptor 4 by the positive corona discharge of the charger 7, and as a result, a negative charge is applied to the interface between the photoconductive layer 2 and the insulating layer 3. is induced, and as a result, the surface of the photoreceptor 4 has a uniform potential as seen in the graph of potential E. If it is difficult to inject charges during this charging process, uniform irradiation with light may also be used to facilitate charge injection.

The image exposure device 8 scans and exposes the original O with white light, and the reflected light enters the surface of the photoreceptor 4 charged as described above as image exposure I, and at the same time, the charger 9 substantially causes the corona of the charger 7 to enter. An alternating current or direct current corona discharge with a polarity opposite to that of the discharge is performed to form a primary latent image consisting of a charge density on the photoreceptor 4 as shown in FIG. 10 [2].

FIG. 10 [2] shows changes due to the red components I and I of the image exposure I. The red component (1) passes through the R filter part of the insulating layer 3 and makes the part of the photoconductive layer 2 below it conductive, so in that part, the negative side of the interface with the insulating layer N3 of the photoconductive layer 2 becomes conductive. The charge disappears. On the other hand, B
, G, and R filter portions do not transmit the red component ①, so the negative charge of the photoconductor N2 remains in those portions. The same applies to the other color component lights 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, which is composed of a charge density corresponding to the intensity of the color component light transmitted through each filter.

However, due to the action of corona discharge from the charger 9, the insulating layer 3
Regardless of the amount of charge on the interface between the photoconductive layer 2 and the photoconductive layer 2, that is, regardless of whether or not the imagewise exposure light (2) is incident, the surface potential of the photoreceptor 4 is approximately zero or negative as shown in the graph of the potential E. The potential becomes constant. This is because the corona discharge of the charger 9 charges the photoreceptor surface so as to balance the charge on the boundary surface, and in this state, the second layer image does not function as an electrostatic image to which toner is attached. In the image exposure device 8, either the optical system or the document table may be of a reciprocating type, or the document passing type may be used.

The uniform exposure device 10B uniformly emits blue light onto the above-mentioned primary latent image forming surface. FIG. 10 [3] shows the change in the charging state due to this. In other words, the blue light is R
, G filter parts do not pass through, so there is no change in those parts, but the B filter part passes through and makes the photoconductive layer 2 below it conductive, thereby making the upper and lower parts of the photoconductive layer 2 in that part conductive. The charges at the interface are neutralized, and as a result, a potential pattern, that is, an electrostatic image, appears on the surface of the insulating layer 3 on the surface of the insulating layer 3 in the blue complementary color image of the previous image exposure, as shown in the graph of the potential E. . The --like exposure device 10B may use a blue light emitting lamp, or may use a combination of a white light lamp and a filter that selectively transmits blue light from the white light. The same applies to the uniform exposure device 10B and IOR, which will be described later.

The electrostatic image formed by uniform exposure to blue light is developed by a developing device 11Y containing yellow toner that is negatively charged by friction. Figure 1θ [4] shows the developed state. That is, the yellow toner TV adheres only to the B filter portion where the potential has changed due to -like exposure to blue light.
It does not adhere to the R and G filter parts where the potential does not change.

As a result, a yellow toner image is formed on the surface of the photoreceptor 4. Note that the development conditions are line drawings related to the image type.

This varies depending on whether the general or photo button is pressed, which will be explained later.

The potential of the B filter portion to which the yellow toner Tv has adhered decreases somewhat, but is still high as seen in the graph of the potential E, and the next time development is performed, toner will adhere and color mixing will occur.

In order to prevent this mixing and color, the charger 12Y performs a corona discharge similar to the charger 9 on the surface of the photoreceptor 4 on which the yellow toner image has been formed.
As shown in the graph, the potential of the B filter portion is lowered to smooth the surface potential to a potential at which toner does not adhere.

The uniform exposure device 10G uniformly makes green light LG incident on the surface of the photoreceptor 4 whose surface potential has been smoothed. From this, a potential pattern appears in the G filter portion, as shown in FIG. 10 [6]. When this potential pattern is developed by the developing device 11M containing magenta toner, the magenta toner adheres only to the G filter portion, forming a magenta toner image as shown in FIG. 10 [7]. As a result, two-color toner images are combined on the photoreceptor 4.

Furthermore, a corona discharge is applied to this image forming surface by the charger 12M to smooth the surface potential as shown in FIG. 10 [8]. Next, the uniform exposure device 10R uniformly applies red light LR to the image forming surface whose potential has been smoothed.

If the original image is in full color, a potential pattern appears in the R filter section, so when this potential pattern is developed by the developing device 11C that stores cyan toner, a cyan toner image consisting of cyan toner attached only to the R filter section is created. is formed. As a result, a full-color image consisting of a composite of yellow, magenta, and cyan toner images is formed on the photoreceptor 4 without color turbidity due to color shift or color mixture.

In the above image forming process, if the original image is a red image and the image exposure (2) is only the red component (1) as shown in FIG. 10 [2], there is no potential pattern in the R filter portion. The cyan toner does not appear and the cyan toner does not adhere even if it is developed by the developing device 11C. That is, in this case,
A red image is formed by combining a yellow toner image and a magenta toner image. At the same time, if the image exposure I consists only of green or blue components, a green image consisting of a combination of a cyan toner image and a yellow toner image or a blue image consisting of a combination of a cyan toner image and a magenta toner image are formed, respectively. . Furthermore, when the document image is a single color image of yellow, magenta, and cyan, a single color image consisting of yellow, magenta, and cyan toner images is formed, respectively.

The above is the color image forming process when the single color designation button is not pressed, and Table 1 summarizes the situation in which the original image is reproduced on the photoreceptor 4 in this process. In Table 1, the symbol "] February means that an image pattern of charge density is formed at the interface between the insulating layer 3 and the photoconductive layer 2 of the photoreceptor, and the symbol rOJ
The symbol "0" indicates that an image-like potential pattern appears on the surface of the photoconductor, the symbol "0" indicates that a toner image is formed, and the symbol "↓" indicates that a toner image is formed.
indicates that the state in the upper column is maintained as it is, and 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.

Developing devices 11Y to IIC and further developing device 11 to be described later.
K uses a developing device as shown in FIG. The developing device shown in FIG. 11 has a plurality of N
, a magnet body 112 having 5 Tet poles arranged on its circumferential surface is provided, and the developer consisting of a mixture of magnetic carrier and toner in the developer reservoir 113 is attracted to the surface of the sleeve 111 by the magnet of the magnet body 112. When one or both of the sleeve 111 and the magnet 112 rotate in the direction of the arrow, the adsorbed developer is conveyed in the direction of the upward arrow on the sleeve 111, and during the conveyance, the layer thickness of the developer is controlled by the layer thickness regulating blade 114. 4 and the sleeve 111, and apply a developing bias consisting of a superimposed voltage of alternating current and direct current to the sleeve 111 from a bias power supply 110 included in the drive circuit shown in FIG. 8 through a protective resistor. This causes toner to fly from the developer layer on the sleeve 111 and adhere to the electrostatic image on the photoreceptor 4 in the development area A where the sleeve 111 faces the photoreceptor 4. The developer on the sleeve 111 that has passed through the development area A is moved to a developer reservoir 113 by a cleaning blade 115.
In the developer reservoir 113, the stirring roller 1
16 is a toner replenishing roller 11 from a toner hopper 117
Stir to uniformly mix with the toner replenished in step 8. This agitation is also agitation that imparts frictional charge to the toner. In this developing device, the sleeve 111 is grounded or floated during non-development, or the AC component of the developing bias is stopped and the voltage applied to the sleeve 111 is set to a DC voltage with the opposite polarity to the charging of the toner. Even without removing the developer layer on the photoreceptor 111, it is possible to bring the photoreceptor 4 into an inactive state without adhering toner to the photoreceptor 4 or disturbing the toner image already formed on the photoreceptor 4. can. In the development by this developing device, if the effective value amplitude V ac of the AC component of the developing bias applied to the sleeve 111- is changed, the surface potential of the photoreceptor 4, that is, the electrostatic image potential, is The amount, that is, the developed density changes as shown in FIG. 12 for the recorded image density. Furthermore, even if the frequency f of the alternating current component of the developing bias is changed, the recorded image density changes as shown in FIG. 13.

In FIGS. 12 and 13, the photoreceptor 4 in FIG. 8 is made of 5eTe.
120 in the direction of the arrow with a photoconductive layer 2 made of a photoconductor.
It rotates at a surface speed of ts/see, the outer diameter of the sleeve 111 of the developing device is 30 m, the gap with the photoreceptor 4 is 700 μm, the rotation speed in the direction of the arrow is 65 rpm, the number of magnetic poles of the la stone body 8 is 8, and the magnetic pole is the same as that of the sleeve 111. Maximum magnetic flux density generated on the surface: 900 Gauss, rotation speed in the direction of the arrow: 700 rpm
The developer used was an insulating magnetic carrier made of a resin containing magnetic powder with a weight average particle diameter of about 30 μm and a resistivity of about 10+Ω as measured with a Coulter Counter manufactured by Coulter or an Omnicon Alpha manufactured by Bausch & Lomb. A gap between the layer thickness regulating blade 114 and the sleeve 111 made of a two-component developer made of a magnetic material, consisting of a two-component developer mixed with positively triboelectrically charged insulating non-magnetic black toner having a weight average particle size of approximately 7 μm at a toner weight ratio of 20%. 300 μm, the layer thickness of the developer layer regulated by 500 μm, the DC component of the developing bias applied to the sleeve 111 -100V, the AC component frequency of 2kHz in FIG. 12, and the AC component effective value amplitude of 100 in FIG.
It shows the result of developing under 0 V conditions and transferring and fixing the obtained toner image onto copy paper. Photoconductivity N of photoreceptor 4
In the case where 2 is made of an n-type semiconductor as shown in FIG. 10, almost the same results can be obtained by reversing the polarities of the electrostatic image potential, the charging characteristics of the toner, the DC component of the developing bias, etc.

As shown in Figures 12 and 13, if the voltage of the developing bias AC component is increased in the range of 100V to 100OV, or the frequency is decreased in the range of 6kHz to 2kHz, the electrostatic image potential changes. On the other hand, the change in development density is thick (and the gradation (γ) is hard).In addition, in order to reproduce images with large contrast such as line drawings, the change in development density is large with respect to the change in electrostatic image potential. Development conditions are suitable, and development conditions with small changes in the degree of change are suitable for the reproduction of gradation such as photographic images.

When the line drawing, general, and photo designation buttons on the operation panel 6 in FIG. 9 are pressed, the developing devices 11Y to II
K develops under the developing bias condition with a large density change gradient as shown in Figures 12 and 13, and when the photo button is pressed, development occurs under the developing bias condition with a small density change gradient, and when the -m button is pressed, the density changes. The developing conditions are changed so that development is performed under a developing bias condition with an intermediate gradient. This control is performed by the CPU that receives specified information from the operation panel 6.
is performed by driving the bias power supply 110 via the D/A converter. As a result, line drawings and gradation drawings in original images are reproduced in tones with clear contrast and tones with gradation, respectively, and images containing line drawings and gradation drawings are reproduced in appropriate intermediate tones. will be reproduced. The Y- slide button for adjusting the density on the operation panel 6 is used to change the developing density by changing the DC component voltage of the developing bias. When the DC component voltage is changed, the developed density changes in such a way that the curves in FIGS. 12 and 13 are horizontally shifted in parallel.

Instead of providing this slide button for adjusting the density, a density reference patch for density is provided on the document table 5, an electrostatic image or toner image of the reference punch is formed on the photoreceptor 4 in advance, and the electrostatic image potential or toner image is It is also possible that the density is detected by a detector and the CPU automatically determines the DC component of the developing bias based on the information.

Next, without pressing the line drawing, general, or photo designation button,
The case where the start button is pressed will be explained. In this case, prior to the above-described image forming step, the swing arm 1 of the document image reading means 13 shown in detail in FIGS. 14 to 16 is
31 reciprocates from the solid line position to the two-dot chain line position in FIG. receives the reflected light from the original O and outputs image information to the CPU via an A/D converter. Light source 13
The color image sensor 133 consists of a B, G, and R filter array and a photoelectric element array that receives the light transmitted through each filter. The reflected light is focused by a lens 134 and enters a color image sensor 133. C.P.
U is the first value from the output information of the color image sensor 133.
Create a density histogram for each color as shown in Figure 7, and use this histogram as a density D that is close to density O, which corresponds to the white background.
It is divided into a relatively low concentration area W from I to D2, a relative medium concentration area Wg from the concentration D2 to 1, and a relative high concentration area W3 with a concentration of 1 or more, wl, Wg.

For each range of W, integrate the frequencies above a predetermined level as shown by Lo in the figure, and if the integrated frequency exceeds an appropriately set judgment level, it is a high density area W, and if it is high, it is a line drawing, low density. If there is only one or both of the area W1 or the medium density area W2, it is determined that it is a photographic image, and if it is also in the high density area W3, it is determined that it is a general surface with a mixture of line drawings and photographic images, and the developing conditions are set according to this determination. And then there's the line drawing.

Generally, the image forming process is performed in the same way as when the photo designation button is pressed.

The reason why the range from density O to 0 is excluded from the judgment when classifying the histogram is because this range corresponds to the white background of the document and does not provide image information. The histogram in FIG. 17 shows the frequency near the density O corresponding to the blank area of the original by canting it. The divisions of the histogram are not limited to the three divisions described above, but can also be divided into four or five divisions. When the divisions are subdivided in this way, even in line drawings, integration frequencies higher than the judgment level may appear in the two sections on the high-density side, so it is necessary to determine that these are also line drawings. For example, when determining a photographic image or a general surface, if there is no integration frequency higher than the judgment level in the highest density category and it is in any other density category, it is considered a photographic image, and the lower density side excluding the highest density category and the next category. If it is in the category, it can be done to make it general. If the classification is too detailed, the judgment conditions will become complicated, so it is preferable to use three classifications.

When controlling the image density by changing the AC component voltage of the developing bias as shown in FIG. 12, the developing conditions for line drawings, photographic drawings, and general images are preferably set as shown in Table 2. In general, the superimposed DC voltage should be set slightly higher for line drawings or general surfaces containing line drawings than for photographic images, to prevent fogging in non-image areas.
In addition, when controlling the image density by changing the AC component frequency of the developing bias as shown in Figure 13, it is preferable to set the DC voltage as shown in Table 3. It is similar to

Table 2 Table 3 The CPU determines that document 0 is blank or not on the document table unless there is a frequency of 50 or more in any of the color density histograms in FIG. When the copy start button is pressed again, the warning display is erased and the image forming process is controlled under the conditions of, for example, a photographic image. Even one of the color density histograms in Figure 17 is a line drawing.

If there is something that can determine whether it is a general image or a photographic image, it will be controlled accordingly. Further, since the determinations in all color density histograms do not necessarily match, if they do not match, it is determined that it is a general surface and the image forming process is controlled.

As described above, even if a person who is not familiar with the operation of a copying machine makes a copy, it is possible to obtain a copy image with excellent reproducibility depending on whether the original image is a line drawing, a general drawing, or a photographic image. In addition,
Although the button for specifying line drawings, general drawings, and photographs in such a copying machine may not be provided, it can be used, for example, to reproduce a photographic drawing with strong contrast like a line drawing.

If the original image is a monochromatic image, if it is copied using the color image forming process as described above, the copied image will have inferior resolution and density compared to those obtained by a copying machine that uses a photoreceptor that does not have a color separation function. become something. This is because, as shown in Table 1, a specific color toner adheres only to a specific color separation filter portion of the photoconductor 4, and as a result, the amount of toner adhering to the entire surface is reduced, or the black-and-white image is In case,
This is due to the fact that the reflectance of color toner is higher than that of black toner. Therefore, if you want to obtain a monochrome image, press the desired monochrome button on the operation panel 6 and then press the copy start button. The image forming process in this case is as follows. That is, the process up to the uniform exposure of the --like exposure device 10B is the same as the color image forming process described above, but the development device 11Y is
, IIM and chargers 12Y and 12M are placed in an inoperative state, and uniform exposure devices 10G and IIM are placed on the next layer image forming surface.
Uniform exposure by OR continues. By this-
Electrostatic images are generated on the B, G, and R filter portions of the photoreceptor 4 from the next layer image. This electrostatic image is transferred to the photoreceptor 4 by the developing device 11C when the single color button C or black is pressed, or by the developing device 11K using black toner as a developer, and by the developing device 11K when the single color button C or black is pressed. Developing device 11 in the rotating eye
If blue, green, or red is pressed by Y or IIM, developing devices 11C and 11M, IIC and II
Developed with Y, IIY and IIM respectively. In this case, all other image forming means, transfer and cleaning means from electrostatic image formation to development are inactive. As a result, a monochromatic toner image can be formed on the photoreceptor 4 with the same resolution and density as that of a photoreceptor without a color separation function. In addition, in the above monochrome image forming process, the --like exposure device 10B is used.

10G, instead of uniform exposure with IOR, e.g.
A combination of a white light lamp and a blue light selection transmission filter may be used in the -like exposure device 10B, and in the monochromatic image forming process, the -like exposure device 10B may perform uniform exposure with white light that does not pass through the filter. . According to this, monochromatic images of all colors can be formed within one rotation of the photoreceptor 4. Tables 4 and 5 show the conditions in which a monochrome image is formed in the above-mentioned monochrome image forming process, and the same reference numerals as in Table 1 indicate the same conditions. indicates that black toner has adhered.

In the above single-color image forming process as well, line drawings and general drawings are used, as in the above-mentioned color image forming process.

Development conditions are determined based on the designation or judgment of the photograph. However, in the case of specifying a single color, development may be performed under general development conditions, for example.

Photoreceptor 4 in a color image forming process or a monochrome image forming process.
The toner image formed thereon is facilitated to be transferred by a pre-transfer charger 14, and is transferred by a transfer device 16 onto copy paper P fed from a paper feeder 15. The copy paper P onto which the toner image has been transferred is separated from the photoreceptor 4 by the separator 17, sent to the fixing device 19 by the conveyance means 18, where the toner image is fixed by the fixing device 19, and then discharged outside the machine.

The surface of the photoreceptor 40 to which the toner image has been transferred is neutralized by a static eliminator 20 that performs exposure and corona discharge, and residual toner is removed by a cleaning device 21 to return to a state where the next image forming process can be performed.

Incidentally, since the filter layer 3a of the photoreceptor 4 is normally not endless, the image forming process is performed a specified number of copies so that the image forming process is not performed on the joint portion of the filter layer 3a. Finally, it stops when cleaning is complete and returns to the starting phase. If the filter jii3a could be formed endlessly, it would no longer be necessary to keep the starting phase constant as described above.

The copying machine shown in FIG. 18 includes uniform exposure devices 10B and I in FIG.
A uniform exposure device 10 as shown in FIG. 19 is provided in place of the OG and IOH, and the chargers 12Y and 12M are omitted and the charger 9 is used instead, thereby reducing the size and weight. This achieved cost reduction. In this copying machine, a monochromatic image is formed within one rotation of the photoreceptor 4, but a color image is formed by multiple rotations of the photoreceptor 4. That is, the color image forming process is performed until the -next layer image formation.
Same as the copying machine shown in the figure, the uniform exposure device 10 shown in FIG.
is opened, the other shutters SG and SR are closed, and the light from the white light lamp is uniformly incident as blue light through filter F.
The electrostatic image thus formed is developed into a yellow toner image by the developing device 11Y, the potential of the developed surface is smoothed by the charger 9 during the second rotation of the photoreceptor 4, and a uniform exposure device is applied to the potential smooth surface. 10 now closes the shutter S, filter F,
The shutter S in front of the shutter S is opened, and the filter FG causes white light to green light to uniformly enter, and the electrostatic image formed thereby is developed into a magenta toner image by the developing device 14M.
The charger 9 smoothes the potential of the developing surface as before, and the uniform exposure device 10 then applies the shutter S to the potential smoothed surface.
0 is closed, the shutter S in front of the filter F is opened, and white light to red light is uniformly incident through the filter F, and the electrostatic image formed thereby is developed into a cyan toner image by the developing device 14C. consists of things. Further, in the monochrome image forming step, the uniform exposure device 10 opens all the shutters Sll, SG, and S11 on the next layer image forming surface to produce blue and green images.

Red light is uniformly incident on the ζ photoreceptor 4, thereby
, the electrostatic images generated on the R filter portion are transferred to the developing device 1.
It consists of developing with any one of 1Y to IIK or any two of 11Y-11C.

This copying machine is the same as the copying machine shown in Fig. 8 in that the developing conditions are determined according to the specification or judgment of line drawing, general, or photograph, and other conditions such as transfer and fixing.

Of course, the cleaning process is also performed in the same way. In addition to the color image forming process described above, the color image forming process of this copying machine is performed by changing the potential of the developing surface of the cyan toner image to the charger 9.
, and a uniform exposure device 10 is applied to the potential smoothing surface of all the shutters S1. S.G.

The SR may be opened to allow blue, green, and red light to enter uniformly, and the electrostatic image formed thereby may be developed into a black toner image by the developing device 11. As a result, a color image whose contrast is enhanced by the black toner image can be obtained. Also in the copying machine shown in FIG.
By providing a charger for potential smoothing and a white light uniform exposure device before step 1, the color image forming process can be contrasted with a black toner image. If a black toner image is formed during the second rotation of the photoreceptor 4,
It is possible to eliminate the need for a charger or a white light uniform exposure device.

The copying machine of the present invention is not limited to the above-mentioned example, and even when the color separation function of the photoreceptor is provided by a photoconductive layer, the charging of the photoreceptor and the exposure such as image exposure or uniform exposure are performed on both the front and back surfaces respectively. The development may be carried out by using a different color toner instead of the yellow, magenta, or cyan toner, or by a method in which development is carried out by attaching toner charged to the same polarity to a low potential portion of the photoreceptor.

〔Effect of the invention〕

According to the copying machine of the present invention, even a person who is not skilled in operation can easily record a copy image with good reproducibility depending on whether it is a line drawing, a general drawing, or a photographic drawing of an original image.

[Brief explanation of the drawing]

1 to 4 are partial cross-sectional views schematically showing examples of the layer structure of a photoconductor used in the copying machine of the present invention, and FIGS. 5 to 7 are distributions of color separation functional elements of the photoconductor, respectively. FIG. 8 is a schematic configuration diagram showing an example of the copying machine of the present invention, FIG. 9 is a partial plan view showing an example of the operation panel of the copying machine of the present invention, and FIG. 10 is a color image. An explanatory diagram of the forming process, FIG. 11 is a schematic configuration diagram showing an example of a developing device used in the copying machine of the present invention, and FIGS. 12 and 13 are diagrams showing the case where the voltage and frequency of the AC component of the developing bias are changed, respectively. A graph showing the relationship between electrostatic image potential and recorded image density. FIG. 14 is a partial plan view of the document table showing an example in which the document image reading means scans the document. FIGS. 15 and 16 are reading diagrams of the document image reading device. A partial sectional view and a partial plan view showing the configuration of the parts, FIG. 17 is a density histogram for each color obtained by processing information of the document image reading means, and FIG. 18 is a configuration showing another example of the copying machine of the present invention. The schematic diagram, FIG. 19, is a sectional view showing an example of a specific light type exposure device used in the copying machine shown in FIG. 18. 4...Photoconductor, 5...Document stand, 6...
·control panel, ? , 9.12Y, 12M... Charger, 8...
Image exposure device, 10, IOB, IOG, LOR... exposure device, 11Y, IIM, IIC, IIK... developing device,
13... Original image reading means, 131... Swinging arm, 1
32...Light source, 133...Color image sensor, 14...Pre-transfer charger, 16...Transfer device, 17
...Separator, 2o...Static eliminator, 21...
・Cleaning device. Patent applicant Konishiroku Photo Industry Co., Ltd., 27.7. −
・Representative Patent Attorney Haru Takashi T2. . Fig. 1 Fig. 2 Fig. 4 Fig. 6 Fig. 7 Fig. 9 - Fig. 11 Fig. 12 Fig. 1 Species (V) Fig. 14 Fig. 15 Fig. 16 / 37732 r53 Fig. 17 Fig. 18 Procedural amendment document February 1986 r Japanese Patent Office Commissioner Black 1) Akio Yu 1, Indication of the case 1986 Patent Application No. 236192 2, Name of the invention Copying machine using a photoreceptor with color separation function 3, Relationship with the case of the person making the amendment Patent applicant address 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name
(127) Konishiroku Photo Industry Co., Ltd. 4, Agent
160 phone number 356-6090 or '-='; 1 5. Date of amendment order January 27, 1985 (shipment date) As shown in the appendix of the drawing (Figure 8) originally attached to the application ( (No change in content)

Claims (2)

[Claims] (1) After charging a photoconductor with a color separation function and exposing the original to light, uniform exposure to a specific light and development with a specific color toner are repeated to synthesize multiple toner images. In a copying machine that forms a color image, a copying machine is provided with an original image reading means for detecting the image density of the original on the original platen for each color, and information from the reading means is used to automatically determine each development condition in the color image forming step. A copying machine characterized in that it allows decisions to be made. (2) The scope of claim 1, wherein each development condition is automatically determined based on the information of the document image reading means when a copy start button is pressed without specifying the type of document image. copy machine.