JPS5878157A - Method and device for three colors image forming - Google Patents

Abstract

PURPOSE:To increase a printing speed by a simple device, by using a drum provided with a recording body layer, resolving an orignal into 3 colors by laser light, giving a latent optical image onto the recording body surface simultaneously, and executing development of 3 colors by one rotation of the drum. CONSTITUTION:A recording body 13 is obtained by providing a photoconductive layer 2 and a transparent insulator layer 3 on a drum 1. Along the circumferential side of the recording body 13, charges 14, 4A, reverse charging charger 4, developing devices 24, 25 and 26, transfer device 29, destaticizer 34 and a cleaner 31. Subsequently, in order to color-separate an original, lasers 17, 18 and 19, rotary mirror 16, scanning mirror 20 and a reflector are provided, the original is resolved into 3 colors of E1, E2 and E3 simultaneously, the recording body 13 is irradiated simultaneously, and a latent optical image is formed. As for this latent optical image of 3 colors, it is color-developed in order by 3 developing devices, and is transferred to transfer paper 30 by a trnsfer device 26. By one rotation of the recording body drum 13, a three colors image is formed, therefore, the printing speed is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-color image forming method using electrophotography and an apparatus therefor.

Conventionally, in order to form three-color images, a drum around which a recording medium is mounted is rotated three times, an image of one color is formed on the recording medium for each rotation, and these three images are overlapped, or the drum is rotated three times. During one rotation, uniform charging of the recording medium, first exposure, first development,
Second exposure, second development.

A method has been adopted in which the third exposure and third development are performed sequentially.

However, the former conventional method has the disadvantage of a decrease in printing speed, and the latter conventional method has the disadvantage of a complicated structure, resulting in inconveniences in the device configuration and an increase in size. Ta.

The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to provide a three-color image forming method that can increase printing speed, and a three-color image forming apparatus that has a simple structure, can be easily manufactured, and can be miniaturized.

In order to achieve the above object, 1 the method of the present invention performs a uniform charging step of uniformly charging a recording medium, and
a first exposure step of exposing a first light image by performing a corona discharge toward the transparent insulator layer portion and focusing a first light image on the photoconductor layer portion below the transparent insulator layer portion; and a second exposure step of exposing the second light image by focusing a second light image on an arbitrary second position photoconductor layer portion of the recording body, and forming the transparent insulator layer at the second position. A first step for developing a first color toner image by depositing a first color toner on the partial surface.
A developing step is performed, and a third exposure step is performed in which a third optical image is focused on an arbitrary third position photoconductor layer portion of the recording medium to expose the third optical image.

A second developing step is performed in which a second color toner is attached to the surface of the transparent insulator layer portion at the third position and a second color toner image is developed, and uniform exposure is performed in which light is uniformly irradiated over the entire surface of the recording medium. a third layer is formed on the surface of the transparent insulator layer portion at the first position.
An apparatus of the present invention is characterized in that a third step of developing a color toner image is performed.

A recording body having a photoconductor layer formed on a conductive substrate and a transparent insulating layer formed on the photoconductor layer and attached to the circumferential side of a rotating drum, and a recording body uniformly a charger for reverse charging that performs a corona discharge for reverse charging toward the uniformly charged surface of the transparent insulator layer portion at an arbitrary first position of the recording medium; Exposure of the first light image is performed by focusing a first light image on a portion of the photoconductor layer, and exposure of the second light image is performed by focusing a second light image on an optional second photoconductor layer portion. a first exposure system including a first exposure optical system that exposes a light image; and a first exposure system that attaches a first color toner to the surface of the transparent insulator layer portion at the second position and develops the first color toner image. a second exposure system consisting of a first developing device and a second exposure optical system that exposes the third light image by focusing the third light image on a photoconductor layer portion at an arbitrary third position of the recording body; .

a second developer for developing a second color toner image by depositing a second color toner on the surface of the third position transparent insulator layer portion; and a uniform exposure light source for uniformly irradiating light over the entire surface of the recording medium. and,
and a third developing device for developing a third color toner image by attaching a third color toner to the surface of the first position transparent insulating layer portion, the charging device.

A first exposure system, a first developer, a second exposure system, a second developer, a uniform exposure light source, and a third developer are sequentially arranged along the circumferential side of the drum, sandwiching the second developer. So number one. 2nd j
t. An optical system is configured to focus the image and the third optical image onto the recording medium, and a three-color toner image is formed on the recording medium while the drum is rotating.

Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a first embodiment of the method according to the invention. In FIG. 1, a photoconductor layer 2 is provided on a substrate 1 of a recording medium 13.
A transparent insulating layer 3 is formed on the photoconductor layer 2.

This photoconductor layer 2 has the property of being an insulator when not irradiated with light and becoming a conductor when irradiated with light, and the transparent insulator layer 3 is an insulator that can transmit light. Consists of.

In the method shown in FIG. 1, before performing the exposure step and the development step of the three-color image, a charging step is performed to uniformly form charge pairs on the surface of the transparent insulating layer 300 as shown in FIG. 1(a). conduct.

In this charging step, it is preferable to charge the surface of the insulating layer 3 positively when the photoconductor layer 2 is of N type, and negatively when it is P type, but this may not be necessary depending on the case. Further, it is preferable to irradiate the recording medium 13 with light at the same time as the above-mentioned charging so that electrification can be easily induced at the interface between the photoconductor layer 2 and the insulating layer 3.

Next, in the method shown in FIG. 1, the following exposure step for reversal development and first exposure step for regular development are performed.

In this embodiment, an exposure step for reversal development is performed first, and then a first exposure step for regular development is performed.

FIG. 1(b) explains the exposure process for reverse development, in which corona discharge is performed using a reverse charging charger 4 toward the surface of an arbitrary portion of the insulating layer 3, and the insulation at the position is Charges on the surface of the body layer 3 are removed. Also, at this time, an insulator layer 3 is formed on the photoconductor layer 2 portion below the transparent insulator layer 3 portion.
A latent light image E is formed through the photoconductor layer 3 in this area.
becomes conductive, and the charge directly on the transparent insulating layer 3 is removed.

In this embodiment, the exposure step for reversal development is performed as described above, and as a result, the potential on the surface of the portion of the insulating layer 3 at the first position becomes approximately 0 port.

Incidentally, in this step, a corona discharge can be performed when the surface potential of the insulating layer 3 at the first position becomes a positive potential depending on the magnitude of the reverse charge, and in this embodiment, a negative DC corona discharge is performed. ing.

In the next first regular development exposure step, as shown in FIG. , are connected, and the charge on the back surface of the transparent insulator layer 3 portion at the second position is removed. As a result, the potential on the surface of the portion of the insulator layer 3 at the second position increases.

After the first regular development exposure step is performed, the following first regular development step is performed. That is, in this embodiment, as shown in FIG. 1(d), the recording medium 1 is coated with the first color toner 5 having a charge of opposite polarity to the surface charge of the insulating layer 3.
3 is performed, and the one-color toner 5 adheres only to the surface of the portion of the insulating layer 3 where the first regular optical image E is formed. - When the first regular developing step is performed in this manner, the first regular optical image E is developed at the second position.

Next, a second regular development exposure step and a second regular exposure step are performed.

The above-mentioned exposure process and development process of this example are shown in Figure 1 (
These steps are shown in e) and (f), and these steps are performed in the same manner as the first regular development exposure step and the first regular development step described above. However, in this second regular development exposure step, a second regular light image E is formed at a third position different from the first and second positions, and in the second development step, the third position is transparent. A second color toner 6 is attached to the surface of a portion of the insulating layer 3 . As a result.

A toner 6 of a second color is placed at a third position on the surface of the transparent insulating layer 3.
A second regular optical image E3 is developed.

Further, in this embodiment, the following charge latent image forming exposure step and reversal development step are performed.

FIGS. 1(g) and 1(h) illustrate the exposure step for forming a latent charge image and the reversal development step. In the exposure process for forming a charge latent image in FIG. 1(g), uniform light E is applied over the entire surface of the recording medium 13. is irradiated. As a result, the layer structure E1
The surface potential of the insulator layer 3 other than the portion of the insulator layer 3 to which the insulator layer 3 is connected increases, and the surface potential of the portion of the insulator layer 3 at the first position relatively decreases, resulting in the formation of a charge latent image. .

Then, in the reversal development process shown in FIG. Develop 1. As a result, an image of the third color is formed on the recording medium 13 at the third position.

Thereafter, a transfer process is performed in which the toners 5, 6.7 are charged, and a reversely charged transfer paper is pressed against the surface of the insulating layer to adhere each color toner 5, 6.7 to the transfer paper. 6
．． The entire process is completed by performing a fixing step of fixing 7 on the transfer paper.

As explained above, according to the method of the present invention, a three-color image is not formed by repeating beam scanning exposure and development three times, so a three-color image can be formed at high speed.

In the present invention, it is also possible to carry out the reversal exposure step in two steps, and an embodiment in this case will be described with reference to FIG.

FIG. 2(a) shows the potential change on the surface of the recording medium 13 during the image forming process in the embodiment shown in FIG. 1, and FIG. It shows the change in the surface potential of the recording medium 13 in the case of this embodiment, which is divided into three times. In the figure, 8°12 is the bright part of the latent light image E, 9 is the dark part, 10 is the bright part of the light image E2, and 11 is the light image E.
3 shows the potential change in the bright area. In addition, 12 is the latent light image E
, shows the potential change after uniform exposure.

In the case of FIG. 2(b), after DC corona charging is performed, a latent optical image E1 is formed on the photoconductor layer 2 at the first position, and DC corona charging is performed again. By doing so as well, it is possible to form a three-color image similarly to the embodiment shown in FIG.

Note that the above corona charge may be an AC corona charge, or an AC corona charge and a DC corona charge may be arbitrarily combined. Further, the subsequent reverse charging effect is not necessarily required, and only the surface position of the recording medium 13 needs to be made uniform.

Next, the apparatus of the present invention will be explained.

FIG. 3 shows a first embodiment of the apparatus of the present invention, in which the recording medium 13 is attached to the circumferential surface of a rotating drum.

As described above, in the apparatus of the present invention, a charger is installed along the circumferential side of the rotating drum, that is, the recording medium 13.

A first exposure type, a second exposure type, a uniform exposure light source 1 and a reversal developing device are arranged in this order. For this reason, in this embodiment, the charger 140, the first exposure system consisting of the charger 4 for reverse charging and the first exposure optical system to be described later, and the Next to the first regular developing device 24, a second regular developing device 24 consisting of a second exposure optical system, which will be described later, is installed.
The exposure system.

Next to this second exposure system is a second regular developing device 25.

Further, next to the second regular developing device 25, a uniform exposure light source 27 is provided.
Furthermore, a reversal developing device 26 is arranged next to the uniform exposure light source 27.

The charger 14 is used for performing charging in the above-described charging process, and the reverse charger 4 is constituted by a simultaneous exposure charger used in the above-described exposure process for reverse development. The developing units 24 and 25 are used for the first regular developing process and the second regular developing process, respectively.

Further, a uniform exposure light source 27. The developing device 26 is used for the above-described exposure process for forming a latent charge image and the reversal development process.

Further, in the present invention, the exposure system consists of the above-mentioned first and second exposure systems, and in this embodiment, these exposure systems are constructed as follows.

In FIG. 3, the light image E1. Modulated scanning beam lights corresponding to E, . Further, the light enters the mirrors 38A and 38B and is irradiated onto the recording medium 13.

Here, the first exposure optical system is a mirror 36A.

36B and 37, a latent light image E1 can be formed on the photoconductor layer 2 portion at the first position of the recording body 13, and a first image can be formed on the photoconductor layer 2 portion at the second position of the recording body 13. A normal optical image E2 can be formed.

Further, the second exposure optical system is a mirror 38A.

38B, and a second normal light image can be focused on a portion of the photoconductor layer 2 at the third position of the recording body 13.

In FIG. 3, in this embodiment, a charger 28 for reversely charging the recording medium 13 is provided next to the developing device 26, and a transfer paper 30 is placed next to the charger 28 on the surface of the recording medium 13.
A transfer device 29 is provided which applies pressure to the substrate and charges it positively. The three color toner images formed on the recording medium 13 are transferred onto the transfer paper 30 by these. And transfer paper 30
These toner images transferred to are fixed to the transfer paper 30 in a fixing step, and a three-color electronic image is completed.

A cleaner 31 is provided next to the transfer device 29, and the toner powder remaining on the recording medium 13 is cleaned and removed, and the cleaned recording medium 13 is used again for image formation.

The embodiment shown in FIG. 3 has the above configuration, and its operation will be explained below.

The apparatus of this embodiment can operate in the same manner as the embodiment of FIG. 1 described above. That is, charge pairs are uniformly formed on the front and back surfaces of the transparent insulating layer 3 by the charger 14. and the first
The charge on the surface of the transparent insulator layer 3 at the position is removed by corona discharge of the reverse charging charger 4, and the photoconductor layer below the transparent insulator layer 3 at the first position is removed by the first exposure optical system. A latent light image E1 is formed on the two portions, and the charge formed on the back surface of the first position transparent insulating layer 3 portion is removed.

Next, the normal light image E2 of the first exposure optical system converts the photoconductor layer 2 portion at an arbitrary second position of the recording medium 13 into a conductor, and removes the charge on the back surface of the transparent insulator layer 3 portion at the second position. and the first regular image is exposed. The first regular image is developed by the developing device 24, and an image of the first color toner 5 is formed at a first position on the surface of the recording medium 13. Further, a second regular image is exposed to a portion of the photoconductor layer 2 at the third position of the recording body 13 by a second regular light image E of the second exposure optical system, and this second regular image is transferred to the developing device 25. Developed with
An image of the second color toner 6 is formed on the surface of the recording medium 130 at the third position. Next, the recording medium 13 is exposed by the uniform exposure light source 27.
A uniform light Eu is irradiated over the entire surface of the recording medium 13 to form a latent light image on the recording medium 13. This latent optical image is reversely developed by the developing device 26, and a third image is formed at a third position on the surface of the recording medium 13. A color toner image is formed.

The three-color toner image formed on the recording medium 13 as described above is reversely charged by the charger 28, and these reversely charged three-color toner images are pressed against the transfer device 29 while being positively charged. The image is transferred onto transfer paper 30 and then fixed thereon.

Note that the toner remaining on the surface of the recording medium 130 after the above-described transfer is removed by the cleaner 31.

The recording medium 13 is used again for image formation.

As described above, according to the present invention, toner images of three colors can be formed for each rotation of the drum.
A color image forming device can be provided.

Further, according to the present invention, since it is sufficient to irradiate the recording medium with three beam light images by sandwiching the first regular developing device, the configuration of the exposure optical system for this purpose becomes easy.

The device can be manufactured inexpensively and compactly.

Note that in the apparatus of the present invention, the Σ signals that modulate the three optical image beams are arbitrarily selected, switched or combined, and the operation of the developing device is selected, thereby producing monochrome or multicolor images. can also be formed. Furthermore, although the laser beam images are each independent in the embodiment of FIG. 3, it is not necessary to do so; for example, one laser beam may be divided and each of these may be modulated. Alternatively, three semiconductor lasers may be formed in a play shape and their laser beams may be made into a bundle and incident on the rotating mirror.

Next, another example of the three-color image forming apparatus according to the present invention will be explained.

FIG. 4 shows this embodiment, and the same members as those in the above-described embodiment of FIG. 3 are given the same reference numerals, and their explanation will be omitted.

This embodiment is almost the same in structure as the embodiment shown in FIG. 3, but the process of forming each color light image is slightly different, and
A and a reverse charging charger 4B are provided.

Note that in this embodiment, the charger 28 is not provided, but a static eliminator 34 and an erase light source 35 are provided before the cleaner 31.

The embodiment shown in FIG. 4 has the above configuration, and its operation will be explained below using FIGS. 5 and 6.

The recording medium 13 is uniformly charged by the charger 14, and firstly, the recording medium 13 is subjected to corona discharge and charging with the same polarity as the above charging by the charger 4A.

Although it is possible to omit one of the chargers 14 and 4A, it is preferable to configure it as in this embodiment in order to quickly and uniformly obtain a high-contrast, high-level latent image.

Next, a reverse polarity corona discharge is performed by the reverse charging charger 4B to expose the latent light image E, and the same steps as in the embodiment shown in FIG. 3 are performed.

Note that after the toner powder remaining on the recording medium 13 is neutralized by the static eliminator 34 and the erase light source 35, it is removed by the cleaner 3.
removed by 1.

FIG. 5 shows the exposure step for reversal development for forming a latent image in FIG. 4.

In this embodiment, the surface of the transparent insulating layer 3 is uniformly charged as shown in FIG. 5(a). . . . The uniform charging of the photoconductor is different from that shown in FIG. That is, charging is performed between the base 1 and the surface of the insulating layer 3. For this reason, in this embodiment, a material with very little charge injection from the base 1 is used for the photoconductor layer 2.

When the photoconductor layer 2 is of P type, the above charge polarity is exactly N.
In the case of a type, it is preferable to take a negative value.

Next, when exposure is performed at the same time as charging to the same polarity, as shown in FIG. A charge is generated in the transparent insulating layer 3, and the surface potential of the transparent insulating layer 3 at the first position is the same as the others. Then, when reverse charging is performed, the surface potential decreases and the polarity becomes reversed, as shown in FIG. Note that if either the charger 14 or the charger 4A is omitted, the surface potentials will be approximately the same in this step.

In this embodiment, the bright portions of each optical image are reversely developed.

FIG. 7 shows still another embodiment of the present invention. In this figure, the same members as those in the previous figures are given the same reference numerals, and the explanation thereof will be omitted.

The apparatus of this embodiment has almost the same configuration as the apparatus of the embodiment shown in FIG. 4, but the uniform exposure light source 27 is next to the simultaneous exposure charger 4A
A uniform exposure light source 40 separate from the above is provided.

The operation of the embodiment shown in FIG. 7 will be explained below with reference to FIG.

In this embodiment, the recording medium 13 is charged, exposed to the light image E1, and simultaneously charged as in the embodiment shown in FIG. It is then reversely charged.

In this embodiment, as shown in FIG. 8, the bright area potential during normal development exposure and the uniform exposure light source 27 are higher than in the case of FIG. 6.
Since the potential after exposure can be set to approximately 0 port, development can be easily performed.

Further, in this embodiment, toners of the same polarity are used for toners 5, 6, and 7, and the optical images E, , E, ., are reversely developed, and the optical image E1 is normally developed. In this embodiment, since each toner 5, 6.7 can be made to have the same polarity as described above, the transfer process can be performed satisfactorily.

Note that when the recording medium 13 described in FIG. 5 is used, and when the same polarity charging after the first exposure or the simultaneous charging during exposure as shown in FIGS. , and there is no need to perform a reverse charging process. Therefore, after this, the exposure and reversal development of the light image E2, and the light image E3
When exposure and reversal development, uniform exposure, and regular development of the optical image E are performed, a three-color toner image is formed on the recording medium 13.

As described above, according to the present invention, a three-color image can be formed at high speed.

Further, according to the present invention, since the configuration of the optical system can be simplified, it is possible to provide a device that is inexpensive, small, and easy to manufacture.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing the method of the first embodiment according to the present invention, FIG. 3 is a block diagram of the recording medium surface potential change of the second embodiment method, FIG. 3 is a block diagram of the first embodiment apparatus according to the present invention, FIG. 4 is a block diagram of the second embodiment apparatus according to the present invention, and FIG. a) and (b) are the optical images E1 of the embodiment in FIG.
FIG. 6 is a diagram showing the change in surface potential of the recording medium in the embodiment shown in FIG. 4, FIG. FIG. 3 is a diagram of changes in surface potential of a recording medium. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Photoconductor layer, 3... Transparent insulator layer. 4... Charger for reverse charging, 5... First color toner, 6...
...Second color toner, 7...Third color toner, 13...
Charger, 16...Rotating mirror, 17, 18.19...
・Laser light source, 20...Scanning mirror, 36A, 36B
, 37° 38A, 38B...Mirror, 24, 25.2
6...Developer, 27...Uniform exposure light source, 29...
Transfer device, 30 pieces/ffl 7i:tm bottom 2m 13 Figure 5 Eyes 3rd figure 1111 - If 4 pieces ¥7 Figure 5 Eyes

Claims (1)

[Claims] 1. A uniform charging step is performed to uniformly charge the recording medium, and a corona discharge is performed toward a transparent insulating layer portion at an arbitrary first position of the recording body, and a portion below the transparent insulating layer portion is A first exposure step of exposing the first light image by focusing the first light image on the photoconductor layer portion of the recording body, and focusing a second light image on the photoconductor layer portion at an arbitrary second position of the recording body. a second exposure step of exposing the second optical image, and a first development step of developing a first color toner image by attaching a first color toner to the surface of the transparent insulator layer portion at the second position; The third optical image is focused on the photoconductor layer at an arbitrary third position on the recording body.
A third exposure step is performed to expose a light image, and a second development step is performed to develop a second color toner image by attaching a second color toner to the surface of the transparent insulating layer portion at the third position, thereby covering the entire surface of the recording medium. performing a uniform exposure step of uniformly irradiating light over the area, and performing a third developing step of attaching a third color toner to the surface of the transparent insulator layer portion at the first position to develop a third color toner image; A three-color image forming method characterized by: 2. A recording body having a photoconductor layer formed on a conductive substrate and a transparent insulating layer formed on the photoconductor layer and attached to the circumferential side of a rotating drum; A charger that uniformly charges a charge, a charger for reverse charging that performs a corona discharge for reverse charging toward the surface of a uniformly charged portion of a transparent insulator layer at an arbitrary first position of a recording medium, and a transparent insulator layer at the first position. Exposure of the first light image is performed by focusing a first light image on a portion of the photoconductor layer below the portion, and a second light image is formed on a portion of the photoconductor layer at an arbitrary second position.
The first light image is exposed by forming a light image of the second light image.
a first developing device that develops a first color toner image by depositing a first color toner on the surface of the transparent insulating layer portion at the second position; By focusing a third light image on a portion of the photoconductor layer at an arbitrary third position, the third position is
a second exposure system comprising a second exposure optical system that exposes a light image; a second developer for developing a second color toner image by depositing a second color toner on the surface of the transparent insulator layer portion at the third position; and a second developer for uniformly irradiating light over the entire surface of the recording medium. an exposure light source; a third developing device for developing a third color toner image by depositing a third color toner on the surface of the first position transparent insulating layer portion; A first developing device, a second exposure system, a second developing device, a uniform exposure light source, and a third developing device are sequentially arranged along the circumferential side of the drum, with the second developing device sandwiched between the first developing device and the third developing device. A three-color image forming apparatus, characterized in that an optical system is configured to connect a second light source and a third light source onto a recording medium, and a three-color toner image is formed on the recording medium while the drum is rotating.