JPS59121356A - Color electrophotographic method - Google Patents

Abstract

PURPOSE:To obtain a color image having high definition by laminating a photoconductive layer having photosensitivity only to respective color light of red, blue and green and two layers of photoconductive layers having different spectral sensitivities by bringing the two layers having overalpped photosensitivity regions into direct contact with each other and performing irradiation and development of the color image. CONSTITUTION:A photosensitive body 1 is formed by laminating photoconductive layers P1, P2, P3, P4, P5 in this order on a conductive base body B. The layers P1, P3, P5 have photosensitivity respectively to only the color light of blue, green and red. The layer P2 has light sensitivity to blue color light and light shorter in wavelength than said light. The layer P4 has the photosensitivity overlapping with the layer P3 and has photosensitivity to a wavelength region of >=700munm. The layers P1, P3, P5 are thus charged to a prescribed polarity and after the layers P2, P4 are charged to a reversed polarity, a color image is irradiated thereto to expose the layers with the image. The photosensitive body is then subjected to development with a cyan toner and primary exposure, development with a cyan toner and primary exposure, development with a magenta toner and secondary exposure and finally development with a yellow toner, whereby the color electrophotographic image is obtd.

Description

[Detailed description of the invention] (Technical field〕 The present invention relates to a color Shishiko photographic method.

(Prior Art) As a color electrophotographic method, a method that combines the Carlson process and color separation is well known. That is, an electrostatic latent image corresponding to the color-separated image of a color image separated by one of the three elephant colors is formed on a photoreceptor having panchromatic photosensitivity, and this electrostatic latent image is The image is visualized using toner containing KN colors that are complementary to the colors of the color separation, and the resulting visible group is transferred onto a recording medium such as paper. Repeat this process for the other two primary colors.
A color image is synthetically reproduced using 640 visible images with different colors that are superimposed and transferred onto the same recording medium.

In this method, to obtain one color electrophotographic image, it is necessary to repeat the Carlnon process as many times as there are color separations.
There is a problem in that it is difficult to improve the efficiency of the color electrophotographic process.

To solve this problem, we need to use as many photoreceptors as there are color separations, and perform the Carlson process required for each color separation simultaneously on each photoreceptor.
#1M'k, A method has also been proposed in which images are transferred onto the same recording medium in an overlapping manner, but this method requires multiple equipment for the Carlson process, including a photoreceptor, so it is difficult to realize this method. There is a problem in that the equipment for doing so becomes larger.

Furthermore, both of the above methods produce visible images that are different in color from each other.
The process of mutually aligned transfer onto the same recording medium is essential, and since perfect alignment is impossible, there is a slight misalignment, which results in good resolution (・A common problem is that color electrophotographic images cannot be obtained.

(Objective) Therefore, the present invention aims to provide a completely new color electrophotographic method that does not have the above-mentioned alignment problem, is highly efficient, and can be implemented with a compact device.

(composition) The present invention will be explained below.

One of the features of the present invention lies in the configuration of the photoreceptor used.

That is, this photoreceptor is constructed by laminating five photoconductive layers on a conductive substrate. One of these five photoconductive layers has photosensitivity only to red light, the other layer has photosensitivity only to blue light, and the still other layer has photosensitivity only to green light. The other two photoconductive layers have photosensitivity to light of one or more colors of blue, red, and green, and also have photosensitivity to light of other colors. However, the spectral sensitivities of these two photoconductive layers are different from each other.

Here, additional explanation will be added regarding the above-mentioned light, blue, and green. That is, in this specification, the above light, blue,
Green is used in a special way.

That is, these are used as colors representative of the three primary colors. Therefore, in this specification, when referring to red and blue-green, these can be replaced with the other three primary colors.

When red, blue, and green actually and literally mean red, blue, and green, this will be specifically stated.

Now, the five photoconductive layers described above are laminated so that the two layers whose photosensitive areas overlap are in direct contact with each other.

Among the photoconductive layers of this photoreceptor, the six layers that are sensitive to only red light, only blue light, and only green light are charged to a predetermined polarity, and the other two layers are charged to the opposite polarity. is charged to.

After each photoconductive layer is charged in this manner, the photoreceptor is illuminated with a color image.

Development is then carried out with a toner colored complementary to the color to which the top photoconductive layer, ie the fifth photoconductive layer, is photosensitized.

Next, the photoreceptor is uniformly irradiated with light that turns only the top two photoconductive layers, ie, the fourth and fifth photoconductive layers, into conductors. This is followed by development with a toner colored complementary to the color to which the third photoconductive layer is photosensitized.

Further, the photoreceptor is uniformly irradiated with light that makes only the third and second photoconductive layers conductive, and finally, a toner colored in a complementary color to the color to which the first photoconductive layer has photosensitivity is applied. Development is performed by

As a result, a color visible image corresponding to the above color image is obtained on the photoreceptor.

Is this color visible image directly fixed on the photoreceptor and used for recording (if the photoreceptor itself is in the form of a sheet)?
Alternatively, it is transferred and fixed onto a recording medium such as paper.

Hereinafter, 8gK will be specifically explained with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a photoreceptor used in carrying out the present invention as an explanatory diagram.

The photoreceptor 1 has five photoconductive layers Pl on a conductive substrate B,
R2, R3, R4, and R5 are stacked in this order. The photoconductive layers P1 to R5 are referred to as first to fifth photoconductive layers in this order.

These first to fifth photoconductive layers have spectral sensitivities as shown by reference numerals 2-1.2-2.2-3.2-4.2-5 in FIG. 2, respectively.

That is, the first photoconductive layer P1 actually has photosensitivity only to blue light, and the third and fifth photoconductive layers actually have photosensitivity only to green light and only red light, respectively. Further, the second light guide layer has photosensitivity to blue light and light with a shorter wavelength, and the fourth light guide layer has a photosensitivity that overlaps with the sixth light guide layer P3, and It has photosensitivity in the wavelength region of 700 nm or more.

The first photoconductive layer JfiP1 and the second photoconductive layer P2 have optical sensitivities overlapping each other in the blue light region, and are provided so as to be in direct contact with each other.

Also, both the third photoconductive layer P6 and the fourth photoconductive layer P4! 1
- Since the spectral sensitivities overlap in the green light region, they are placed in contact with each other.

Each of these photoconductive layers is formed by coating an organic photoconductor or dye-sensitized zinc oxide-resin (inder) either sequentially or simultaneously using a dipping method or a spray method. Floating circles are about 3 to 20 μm, preferably about 5 to 10 μm.

Now, below is a color electrophotograph according to the present invention).

Explain the process.

First, for the photoconductor IK, remove the green light component from the white light.
uniformly irradiates light. This kind of light can be easily obtained by filtering white light through a filter that does not allow the color light component to pass through.

Pantonoshui/L.Tar as mentioned above has a vapor deposition rate of 16
It can be easily created with one model. When irradiated with such light,
In the photoreceptor 1, except for the sixth photoconductive layer P3 <41m
It will be easily understood by looking at the distribution of spectral sensitivity in FIG. 2 that all of the photoconductive layers become conductive.

- In such a state, when a positive corona discharge was applied to the photoreceptor, an electric double layer was formed via the state shown in FIG. 3 (IJ, that is, the third photoconductive layer P5) 7. The state is realized. Therefore, by comparing the third photoconductive layer P3 to a capacitor, this state is considered to be the case where the photoconductive layer P3 is charged.
Considering the direction of the dipole moment in the multilayer, let's define this state as 5, for example, when the photoconductor VIP6 is positively charged.
On the other hand, when light in a wavelength range of 700 nm or more is irradiated, only the fifth photoconductive layer P5 becomes a conductor.

In this state, if a negative corona discharge is performed, the result will be as shown in Figure 3 (
The situation shown in II) can be realized. However, here,
It is assumed that there is rectification of holes between the conductive substrate B and the first photoconductive layer P1. According to the previous expression, Figure 3 (
The state shown in 1) is a state in which both the second photoconductive layer P2 and the fourth photoconductive layer P4 are negatively charged.

Next, when a positive corona discharge is applied in the dark,
The state shown in FIG. 3 ([1] is realized.

In this state, the first, third, and fifth photoconductive layers P1. R3°R5 is charged to positive polarity, and the second and fourth photoconductive layers are charged to negative polarity (.

Note that the first positive corona discharge is called primary charging, the next negative corona discharge is called secondary charging, and the third positive corona discharge is called tertiary charging. For example 1
+800■ after the next charge, -200■ after the second charge, 6th
Assume that the voltage is +500 V after the next charging.

In this state, as shown in FIG.
Perform image exposure.

It is assumed that a color original O has a white background part WVc, a black part N, a cyan part C, a 7471 part M, one yellow part Is Y, a red part R1 edge G, and a back part B.

First, considering the part of the photoreceptor corresponding to the black area N, this part is hardly exposed to light, so the surface potential of this part is maintained at about +500 . On the other hand, at a portion corresponding to the white portion W, the photoelectric state of each light guiding layer is canceled by the photoconductive phenomenon, so that the surface potential of this portion becomes approximately OV.

Next, considering the part corresponding to the cyan part C, the wavelength range of the n/n light is an intermediate range between green and blue, and that wavelength range is the spectral range of the first to fourth photoconductive layers P1 to P4. In the sensitive region Kli, the charged state of these four photoconductive layers disappears, and only the charged state of the fifth photoconductive layer P5 remains, and the surface potential becomes 400 to 500 V.

Similarly, in the part corresponding to the magenta part MK, the first and second
, the fifth photoconductive layer Pi, the fifth charging state is resolved,
The surface potential is reversed to a negative polarity of about -ioov.

In the portion corresponding to the yellow portion Y, the sixth, fourth, and fifth photoconductive layers P3. 4th. The fifth charging state is eliminated, and the surface potential becomes about -100V. In addition, in the part corresponding to the red part R, the charged state of the fifth photoconductive layer is eliminated, and the surface potential is
The voltage will be approximately -100V.

At the portion corresponding to the edge G, the sixth and fourth photoconductive layers P3.
The fourth state of charge is eliminated and the surface potential is +400~5
00V. Finally, in the area corresponding to back B,
First and second photoconductive layers P1. The second state of charge is eliminated and the surface potential becomes +400 to 500V3, so the fifth
The photoconductive layer P5 is colored with a light-sensitive color, -4, that is, the complementary color of red, that is, cyan, and is negatively charged.
Cyan area C1 edge G, blue rfB Photoreceptor corresponding to B =
Position B is developed. This state is shown in FIG. 6ffJ.

Next, as shown in FIG. 6 (Vll), a light "45" that turns only the fourth and fifth photoconductive layers P4. When the charged state of the fourth and fifth photoconductive layers is released, 777 parts C are newly generated.
The surface potential of the parts corresponding to the area is 0, and the surface potential of the photoconductor parts corresponding to the black part N, magenta part M, red part R, and blue back part is +400 to 500 V, yellow part Y, and edge CVc.
At the corresponding site, the surface potential is approximately -ioov. This uniform irradiation is called primary light.

Therefore, development was carried out using magenta toner TM, which is negatively charged and colored magenta, which is a complementary color to green, which is the color that has the highest photosensitivity of the sixth photoconductive layer P3. , then the second and sixth photoconductive layers P2. P,
! The photoreceptor 1 is uniformly irradiated with the light L25 that turns i into a conductor (Fig. 3 (Mll). This light L23 has a wave J￥60
The component in the wavelength range of 400 to 500 nm is removed from the light in the range of 0 to 600 nm using a pantone filter. As a result of this uniform exposure, the charged state of the first photoconductive layer P1 is as follows: black part N, yellow part Y, red part R1.
The photoreceptor surface potential remains only at the edges (corresponding to Ic), and the surface potential of the photoreceptor at these locations is +400 to 500 cm, and approximately OV at other locations. This uniform irradiation is called secondary exposure.

Therefore, the first photoconductive layer is colored yellow, which is a complementary color to the blue light to which the first photoconductive layer is sensitive, and is developed with yellow toner TY, which has a negative polarity.

In this way, a color-1jr visual image for the original 4740 VC is obtained on the photoreceptor 1 (FIG. 6 (target)).

In this color image, black is cyan toner TC1
The color is a mixture of magenta toner TM and yellow toner TY, and the red color is a mixture of yellow toner TY and magenta toner TM.
It is expressed by a mixture of colors. Also, the green color is yellow toner TY
The blue color is a mixture of cyan toner and TC, and the blue color is magenta toner.
Each color is expressed by a mixture of TM and cyan toner TO.

All that remains is to either transfer this color visible image to the photoconductor iK and use it for recording (when the photoconductor 1 itself is in a sorted state), or transfer and fix it to another suitable recording medium, such as paper. It would be good to submit it for the record (・.

In conclusion, the features of the color electrophotography of the present invention can be described as follows. In this case, an electrostatic latent image corresponding to the color-separated image that would be obtained if color separation was performed using a blue filter was formed on the first light-guiding layer P1, and a wax color separation image that would be obtained when color separation was performed using a green filter was created. An electrostatic/i image corresponding to a color-separated image that would be obtained by color separation using a red filter is formed in the third and fifth light guide layers P3. P
5VC, respectively, are formed at the stage of color image exposure (Fig. 6 (concave)) as positive charge. However, the electrostatic 7 group image corresponding to the color separation image by the blue filter is formed on the second photoconductive layer P2. The electrostatic latent image corresponding to the color-separated image by the green filter is also formed as a negative charge in the fourth optically exclusive layer P4 in the form of a negative charge.

Therefore, at the stage of color image exposure (FIG. 3, 11VI), electrostatic latent particles corresponding to the color-separated images produced by the evening filter and the green filter are not formed on the surface.

This is visualized by sequentially extracting it with light irradiation alternating with development, that is, with first and second exposure.

FIG. 4 schematically shows changes in the photoreceptor surface potential at each step shown in FIG. 6. N.C.G.

B, W, M, R, and Y indicate the surface potentials of the portions corresponding to the same reference numerals shown in FIG. 3 (11V)K.

FIG. 5 schematically shows only the essential parts of an example of an apparatus for carrying out the present invention.

Reference numeral 10 indicates a tram-shaped photoreceptor, and this photoreceptor 10 rotates in the direction of the arrow. It is assumed that the spectral sensitivity of each photoconductive layer is as shown in FIG.

Red lead 11, 12. 3 shows chargers for the primary, secondary, and 6th-order bands, respectively. Charger 11.12
consists of a charger, light source, and filter.

Symbols 15, 17, and 19 are developing devices, and symbols 16 and 18 are
Lamps for primary and secondary exposure, respectively. It has 16°F1a.

Symbol 20 is a transfer charger, symbol S is recording paper, symbol 2
1 is a cleaner, and 14 is a color image.

While rotating the photoreceptor 1 in the direction of the arrow, charger 11
．． At step 12.13, primary charging and sixth charging are performed, and then image exposure is performed using the color image 1 image 14, and the developing device 1
5, perform development with cyan toner TCK, and then turn on lamp 1.
6, primary exposure is performed, and a developing device 17 performs development using magenta toner TM. Next, if secondary exposure is not performed in the rung 18 and development is performed with yellow toner in the developing device R19, each process shown in FIG. Since a color electrophotographic image is obtained, it is transferred from the transfer charger 20K to a recording medium S, which is a recording medium, and fixed by a fixing device (not shown) to obtain a desired color electrophotographic image.

(Effects) As described above, according to the present invention, a novel color photography method can be provided. With this color electrophotographic method, a color electrophotograph 7 can be obtained with one image exposure, so the process is efficient, and since color images are formed on the same photoreceptor, each color is different. High-resolution color images can be obtained without the need for image alignment.

[Brief explanation of drawings]

1 to 4 are diagrams for explaining the present invention, and FIG. 5 is an explanatory front view schematically showing only essential parts of an example of an apparatus for carrying out the present invention.

Claims (1)

[Scope of Claims] A photoconductive layer having photosensitivity only to red light, a photoconductive layer having photosensitivity only to blue light, a photoconductive layer having photosensitivity only to green light, and red and blue lights. , two photoconductive layers having different spectral sensitivities and having photosensitivity to one or more of green light and light of colors other than these, on a conductive substrate,
The photoreceptor is made up of five layers, with two overlapping photosensitive areas in direct contact with each other, and has six layers that are sensitive to only red light, only blue light, and only green light. After charging the conductive layer to a predetermined polarity and charging the other two photoconductive layers to a polarity opposite to the above predetermined polarity, this photoreceptor is irradiated with a color image to perform image exposure. Development is carried out with a toner colored to the complementary color of the color to which the photoconductive acid layer has photosensitivity (...), and then only the top photoconductive layer and the fourth photoconductive layer below it are developed with light that makes them electrically conductive. , the photoreceptor is uniformly exposed (...), and then the third photoconductive layer is exposed to the complementary color KN color of the color to which the third photoconductive layer exhibits photosensitivity.
Perform development with the toner that was
The photoconductor is uniformly exposed to light that converts only the photoconductive layer into a 4-electrode, and the bottom photoconductive layer is developed with a toner colored to the complementary color of the color for which it has photosensitivity. , the above color drawing 1
4) Color electronic photography method according to the color image.