JPS6027027B2 - Color electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color electrophotographic apparatus, and more particularly to a color electrophotographic apparatus in which reproduction of an original positive image or a negative image can be easily selected.

and an apparatus capable of producing positive-positive prints from color originals (i.e., color positive prints from color transparency originals) based on color electrophotography;
- Various apparatuses have been proposed for obtaining negative and positive prints from originals (ie, color positive prints from color transparent negative originals).

However, the equipment used to produce positive and positive prints and the equipment used to produce negative and positive prints are very different in terms of functionality. It is necessary to use toner with the same polarity as the image potential and to perform reversal development using a developing electrode, making it practical to selectively obtain negative/positive prints and positive/positive prints with a simple switching operation. There were no dual-purpose machines. SUMMARY OF THE INVENTION In view of the above-mentioned points, it is an object of the present invention to provide a novel color electrophotographic apparatus that can produce positive-positive prints and negative-positive prints from a color original by a simple switching operation.

The apparatus of the present invention has a structure that can effectively carry out two different types of color electrophotographic processes, and the structure is briefly described below.

In color electrophotography for obtaining a positive copy image from a positive or negative original, a photoreceptor having a conductive layer, a photoconductive layer, and an insulating layer; a primary charging means for uniformly charging the surface of the photoreceptor; an optical image exposure means for projecting original color separated light onto the photoreceptor after primary charging; and a discharge means for attenuating the surface charge of the photoreceptor acting on the photoreceptor simultaneously with or prior to the exposure of the exposure means. , an entire surface exposure means for applying uniform light to the photoreceptor after exposure by the optical image exposure means, and a projection device used for projecting a color negative film onto the photoreceptor, When using a color negative film, the discharge means exposes the light image exposure means to a light intensity set to a higher amount of light than when producing an original color positive image, on the downstream side of the discharge means in the direction of movement of the photoreceptor. On the other hand, when a color positive image is used for the original, the above-mentioned discharge means and optical imaging means are simultaneously applied to the photoreceptor and the entire surface exposure means is not activated. It is characterized by causing it to act.

As an effective electrophotographic method that can be applied to the color electrophotographic apparatus of the present invention, for example, Japanese Patent Publication No. 42-2
There are methods described in No. 391 and Japanese Patent Publication No. 44-13437.

Special public interest in color positive print
The method described in Publication No. 91 is applied. That is, using an electrophotographic photoreceptor having a photoconductive layer and an insulating layer on a conductive support, the surface of the chick-resistant layer of the photoreceptor is uniformly charged by corona discharge, and the photoconductive layer and Charges are captured at or near the interface of the insulating layer, and then a light image is irradiated onto the surface of the photoconductive layer, and the polarity is opposite to that of the previous one, or corona discharge of the light stream is performed, and insulation is created depending on the brightness of the light image. The charge on the photoconductive surface is discharged, and the entire surface of the photoconductive layer is uniformly exposed to light, and the captured charge in the area corresponding to the dark part of the image is discharged to form a static exposure bath image, which is then exposed to light with the same polarity as the captured charge. Developed with toner,
A print is obtained by transfer, and this is done for each color separation image of a color original, and by forming an overlay color print, color reproduction with the same brightness and darkness as the color nukabashi is achieved. That is, in the above-mentioned color electrophotographic process, first, the photoreceptor is charged by corona discharge,
Next, the light image of the color original is projected onto the photoconductive layer through a filter of one of the three primary colors of the additive color method, for example, blue, while performing corona discharge of opposite polarity or alternating current. A blue separation image is formed by forming an image, developing it with one of the three subtractive primary colors in a toner that is an aftercolor of the filter color, i.e., yellow, and transferring it to another support, such as paper. do. Next, a color separated image is formed in the same way, but this time the light image is projected step by step through a green filter, and magenta toner is used for development.
In addition, for transfer, the previous yellow image is correctly positioned on top of the blue separated image, and superimposed transfer is performed to form a magenta line separated image superimposed on the yellow image.

Finally, in the same way, the light image was projected through a red filter, developed using cyan toner, and properly aligned and superimposed on the magenta color image to be superimposed on the green separated image of the magenta color. Forms a cyan red-separated image. In this way, an overlay color print is formed. If necessary, use a yellow filter to form a latent image, develop it with black toner, align it correctly on top of the color print, and perform superimposed transfer to improve the image quality by overlapping a so-called black plate. It is also possible to consider the following. Next, for color negative positive prints, the method described in Japanese Patent Publication No. 44-13437 is applied.

That is, using the same electrophotographic photoreceptor as above, the surface of the insulating layer of the photoreceptor is charged by corona discharge, and charges are captured at or near the interface between the photoconductive layer and the insulating layer. Then, a corona discharge of opposite polarity or alternating current is performed to discharge the charges on the surface of the insulating layer. Furthermore, a light image is irradiated onto the surface of the photo-thunderelectric layer, and the captured charge is selectively discharged according to the brightness of the light image, forming a static exposure latent image, which is developed with a toner that has the same trough as the captured charge, and is transferred and printed. is obtained,
This is done for each color-separated image of a color negative original, and by forming an overlay color print, the original is reproduced as a color-positive image in which the brightness and darkness are reversed. In the apparatus of the present invention which switches and applies the above-mentioned processes, primary band flea and reverse polarity corona charging,
Alternatively, the operating position of the AC corona charge eliminating means is switched to the same layer as the exposure position, or to the position after primary charging and before exposure.

In an apparatus according to one embodiment of the present invention, a plurality of disarming means that are selectively operated are arranged at the disassembly exposure position and a position in front of the exposure position. Another specific device configuration is one in which a single static eliminating means is provided movably along the photoreceptor movement path and is switched between the above-mentioned disassembly exposure position and a position in front of this exposure position. Applicable.

In this case, a moving mechanism is required, but the static elimination unit,
Power supplies etc. are simplified. Furthermore, a different concrete example of the apparatus configuration is such that the decomposition light position is moved and switched to a position at the same level as the static eliminator position or a position after it.

In this case, it is practically necessary to avoid fluctuations in the optical distance and to fix the optical system after transfer, but the static elimination unit, power supply, etc. are simplified, as in the above example.

As mentioned above, even in the case of deviation, it is necessary to perform control so that the entire surface exposure means is activated when the static eliminating means and the decomposition exposure are activated simultaneously.

Therefore, in the apparatus of the present invention, when changing the reproduction between positive-positive print and negative-positive print, the operation position of the color separation exposure and disarming means is changed, and the operation of the entire surface exposure means is also changed. At the same time, switching control is performed.

Furthermore, in switching between positive-positive printing and negative-positive printing, it is important to control the amount of color separation exposure.

This is because the color exposure amount for color negative and positive prints must be greater than that for color positive and positive prints, and the color negative original used for color negative and positive prints is Generally dye color correction (
This is because it has an orange mask image for masking).

The blue, green, and red filter densities of the unexposed area of commercially available color negative film from Company A after development are 0.63 and 0, respectively.
．． 48, 0.21, and the blue, green, and red filter densities of the transparent part of the color reversal film from Company A after development were all 0.18; Company C's color negative film and color reversal film were about the same level. For this reason, blue, green, and
The red color separation exposure is 2.8 times and 2.5 times higher than that for color positive and positive prints, respectively. sound, 1.1
Requires double. Therefore, when switching the reproduction between color negative/positive prints and color positive/positive prints, it is extremely important to switch the color separation exposure amount.

As a specific example of changing the color separation exposure amount, the input voltage of the light source can be changed by phase control using a slide duff. However, making large or medium voltage adjustments is not always satisfactory because in the former case there is a problem of heat generation, in the latter case there is a problem of noise generation, and in both cases there is a common adverse effect on the halogen cycle. In one of the embodiments of the present invention, dedicated filter groups with different amounts of transmitted light are selectively used for negative/positive prints and positive/positive prints, and each filter group has blue, green,
It consists of a set of red filters.

Furthermore, it is effective not only to simply change the amount of transmitted light between the dedicated filter groups, but also to vary the wavelength range of the spectral transmission characteristics of the filters depending on the original characteristics.

That is, good results can be obtained by varying the spectral transmission characteristic wavelength of each filter group depending on the original so as to improve the color balance of the reproduced print.

Also, as this color separation exposure amount switching means, a set of blue, green,
It is effective to provide a filter group for adjusting the exposure amount using an ND filter or the like together with the red filter group.

At this time, appropriate exposure is provided by selectively using a filter for adjusting pseudo-light amount in accordance with the selection of the reproduction print, as well as at the foot of the color separation filter. In addition to the ND filter, it is also effective to use a CO filter for color balance adjustment, which is used in silver halide color printing, either exclusively or in combination with the filter for adjusting the exposure amount.

On the other hand, in the selective reproduction of positive/bodi prints and negative/bodi prints, better results can be obtained by (adjusting) the latent image potential characteristics.

That is, the image gamma value of normal color negative film is 0. Before and after the mirror, on the other hand, with color positive film, it is 1. It is around the time of silkworm.

If this film is directly printed under the same beach image forming conditions, the gamma values of the reproduced images will differ by a large amount, which is not preferable for the purpose of the apparatus aiming to obtain uniform image quality.

Therefore, for both color negative/positive prints and positive/positive prints, for example, the gamma value should be set to 1.
It is effective to adjust the electrostatic latent image potential so that it becomes 0.

In each case, it is effective for this switching adjustment to effectively set the voltage applied to the primary charger or the voltage applied to the static eliminator to a predetermined value.

FIG. 1 shows a sectional view of an embodiment of a color electrophotographic apparatus according to the present invention.

In the illustrated example, a color negative or positive film projection adding device 29 is mounted on a document table glass 2 of a color copying machine using an NP type photosensitive drum 1. First, I will explain color, positive, and positive prints.

Positive 9 film 292 fixed to film fixing frame 29
is irradiated through a condenser lens 295 by a light source 294 equipped with a reflecting mirror 293, and a projection lens 29
A light image is projected onto the original glass plate 2 through a Fresnel lens 30. The projected image on the document platen glass 2 is mirrors 4, 5, lens 6, mirror 7,
Blue 8, green 83, red 83 can be switched according to each color separation
, color separation filter group 8 having ND84 filters
, ND9 which is switched corresponding to the color separation filter group 8.
5 (density 0.45), ND96 (density 0.30),
The light passes through a mirror 10 and an ND filter group 9 including ND97 (density 0.05) and ND98 (density 0) filters, passes through an AC static eliminator 11, and is exposed onto the photosensitive drum 1. That is, 8, and 95 for blue fog, and 82 and 9 for green exposure.
6. During red exposure, the light is illuminated through filters 83 and 97. The illumination lamp 3 and mirrors 4 and 5 in the optical system are moved to positions 3', 4' and 5', respectively, in synchronization with the rotation of the photosensitive drum 1.

The photosensitive drum 1 is cleaned by a cleaning blade 12, neutralized by an AC static eliminator 13, then positively charged (10) by a primary charger 14, and then charged by an AC static eliminator 1.
1, charge removal is performed simultaneously with image exposure. Furthermore, the entire surface of the photosensitive drum 1 is exposed to light from 15 light sources, and yellow 16, magenta 162, cyan 163, and black 1
The toner is developed with negatively charged toner supplied by one of the developing means 16 having units for supplying 64 color developers. On the other hand, the transfer paper 18 in the cassette 17 is fed into the machine by the paper feed roller 19, and the rough timing is interrupted by the first register roller 20, then the transfer paper 18 in the cassette 17 is transferred to the second register roller 22 via the intermediate roller 21. Accurate timing is taken to ensure that the gripper 23. of the transfer unit 23 holds the transfer material. is maintained. Next, while the transfer paper 18 passes between the transfer corona charger 232 and the photosensitive drum, the toner image on the photosensitive drum is transferred onto the transfer paper. The gripper 23 (holding the transfer paper 18) transfers the toner image onto the transfer paper 18 by making three rotations in the case of full-color copying or one rotation in the case of monochrome copying. After the transfer is completed, the transfer paper 18 is released from the gripper 23, guided to the conveyor belt 25 by the operation of the separation claw 24, and further delivered to the roller fixing device 26 where it is heated and fixed. Thereafter, the transfer paper 18 is discharged to the tray 27. Further, after the transfer, the surface of the photosensitive drum 1 is cleaned by a cleaning blade 12 and the process proceeds to the next cycle. In this way, a color positive print is obtained on the transfer paper. Next, color, negative, and positive prints will be explained.

An optical image of a negative film is projected onto the original table glass 2 instead of the positive film of 292.

The projected light image is a path of mirrors 4, 5, lens 6, mirror 7, color separation filter group 8 which is switched according to each color separation, ND98 (density 0) filter of fixed ND filter group 9, and mirror 10. is exposed to the photosensitive drum. At this time, the AC static eliminator 11 is not operated.

The illumination lamp 3 and mirrors 4 and 5 in the optical system are moved to positions 3', 4' and 5', respectively, in synchronization with the rotation of the photosensitive drum 1. The photosensitive drum 1 is cleaned by a cleaning blade 12 and neutralized by an AC static eliminator 13, then positively charged (10) by a primary charger 14, and then static neutralized by an AC static eliminator 28. Furthermore, the photosensitive drum 1 is given image exposure. In this process, the entire surface exposure light source 15 is not turned on. Next, photosensitive drum 1 is yellow I61, magenta 162, cyan 163 and black 1.
The toner is developed with negatively charged toner by one unit in the developing means 16, which has a plurality of units providing 64 color developers. The subsequent operations are performed in the same manner as in the color positive print described above to obtain a color positive print on the transfer paper. FIG. 2 is a partial cross-sectional view showing a modified example of the fog optical system portion of the apparatus according to the embodiment of the present invention.

In this modified apparatus, the original is projected directly onto the photoreceptor surface, and a pew screen for checking the projected image is also provided. Reference numeral 29 denotes a color film projection device, in which an original film 292 is inserted and moved into a film fixing frame 29 having a slit-like opening, and light from a light source 294 having a reflector 293 is irradiated through a condenser lens 295.

The original scanning light image transmitted through the slit opening is projected onto the photoreceptor 1 via the optical lens 296, the color separation filter groups 30 and 31, the movable mirror 32, and the fixed mirror 10.

Color separation filter groups 30 and 3 provided on this optical path
1 has blue, green, and red color separation filters having mutually different spectral transmittance characteristics, and also has one ND(0) filter.

Therefore, the ND(0) filter 31 of the color separation filter group 30 may be combined with any of the blue, green, and red color separation filters, or the ND(0) filter 31 of the color separation filter group 30 may be combined with any of the color separation filters of the color separation filter group 30. Combinations of ND(0) filters can be selectively implemented.

At this time, a color separation filter group 30 is used for positive and positive purposes.
When the color separation filter group 31 is used for negative and positive use, it is preferable that the transmittance of the filter group 30 is lower than that of each filter of the 31 filter groups.

In the case of color positive/positive printing, the color separation filter group 31 is fixed to an ND (0) filter, and each color separation filter of the filter group 30 forms an optical image.

At this time, a corona discharger 13, a front light lamp 13, a primary charger 14, a corona discharger 11 for static elimination, and a lamp 15.
is activated and the corona discharger 28 is switched to deactivation. On the other hand, in the case of color negative/positive prints, the ND(0) filter is fixed for each color separation filter group 3, and each color separation filter of the filter group 31 is used.

At this time, the corona discharger 13, the front light lamp 1
3. The primary charger 14 and the demobilization corona discharger 28 are switched to the operating state, and the corona discharger 11 and the lamp 15 are switched to the non-operating state. The apparatus of this embodiment has a view screen 34 for monitoring, and prior to light image exposure, the movable mirror 32 is moved to the 32' position, and the mirror 331 enables projection observation onto the screen.

Further, it is effective to use a half mirror as the movable mirror 32 because the mechanism can be simplified.

As described in detail in the above specific examples, the apparatus of the present invention has a simple configuration and can quickly obtain original negative/positive prints and positive/positive prints, while maintaining image quality with good gradation density of both prints. It is possible to obtain.

Since the color balance of the color reproduction image can be well adjusted according to each original, an image with excellent color balance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view illustrating an embodiment of the apparatus according to the present invention, and FIG. 2 is a partial sectional view showing a modification of the exposure optical system. In the figure, 1...photoreceptor, 2...document stand,
3... Irradiation light source, 4, 5... Moving mirror, 6... Lens system, 7, 10... Reflecting mirror, 8, 9... - Color separation filter group. Younger brother 1 younger brother 2

Claims (1)

[Claims] 1 In color electrophotography to obtain a positive copy image from a positive or negative original, conductive layers, photoconductive layers,
a photoreceptor having an insulating layer; a primary charging means for uniformly charging the surface of the photoreceptor; a photoimage exposure means for projecting an original color separation onto the primarily charged photoreceptor; means for acting on the photoreceptor at the same time as or prior to exposure to attenuate the surface charge of the photoreceptor; full-surface exposure means for applying uniform light to the photoreceptor after exposure by the optical image exposure means; and color. - A projection device used to project a negative film onto a photoreceptor as an original, and when a color negative film is used as the original, the discharge means is Exposure by a photoimage exposure means set to a large amount of light is applied to the photoreceptor on the downstream side of the discharge means in the direction of movement of the photoreceptor, so that the entire surface exposure means does not act, while a color positive image is used as the original. A color electrophotographic apparatus characterized in that, in some cases, the discharge means and the photoimage exposure means are simultaneously applied to the photoreceptor, and the entire surface exposure means is further applied.