JPS604461B2 - Image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic image forming method using a multilayer structure photoreceptor having at least an electrode, a photoconductor layer, and an insulator layer, and more particularly to a method for forming an image by electrophotography, in which two types of electrostatic latent images are formed on the photoreceptor. It relates to a method of forming a .

At present, many electrophotographic recording devices have been announced, and multicolor recording is attracting particular attention.

An example of this is color recording by electrophotography using a multilayer photoreceptor such as xerography NP and KIP. It is hoped that by applying this kind of multicolor recording to the field of information processing, for example, by color-coding form records and data records, or by color-coding the recorded contents, it will be easier to read and make a stronger impression on readers. can. As a method for performing two-color recording for this purpose, the above-mentioned xerography, or color recording using the NP or KIP system can be applied. That is, when there is only one photoreceptor, a static exposure latent image is first formed on the photoreceptor, this is developed with toner particles, and the developed toner image is transferred to recording paper. Two-color recording can be obtained by performing the process twice with different colors. This method has the drawback that the time required for recording is twice that of the one-color method, and that continuous recording cannot be performed on a roll of recording paper. Furthermore, two-color recording can be obtained by using two photoreceptors and forming a single-color toner image on each photoreceptor using conventional technology, and transferring the images overlappingly onto a recording medium, but this requires two conventional devices and is large-scale. It had the disadvantage that it became a poor device. The development of a simpler two-color recording method has been awaited. SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method characterized by forming two types of electrostatic latent images, positive and negative, on a photoreceptor, in order to solve the above-mentioned conventional drawbacks.

According to the present invention, a photoconductor having a multilayer structure consisting of at least a transparent electrode, a photoconductor layer, and a transparent insulator layer is used, and while optical information is irradiated from both sides of the photoconductor layer, AC corona is applied to the photoconductor. It is characterized by forming two types of electrostatic latent images having positive and negative polarities on the photosensitive plate by sequentially performing a means for applying electric discharge and a means for irradiating the entire surface of the photoconductor layer with light. An image forming method is obtained.

The photoreceptor used in the present invention is, for example, as shown in FIG.
A light source consisting of a transparent electrode 2 such as a metal oxide film or a metal thin film such as No. 3, a charge injection blocking layer 3 such as a transparent insulator, and a photoconductive substance (for example, Se, CdS, CdSe, Zn○, organic semiconductor, etc.) A photoreceptor made by sequentially laminating a conductor layer 4 and a transparent insulator layer 5 such as fluororesin or polyethylene terephthalate, or a transparent support substrate 6, a transparent electrode 7, and a photoconductor layer 8 as shown in the opening of the figure. A photoreceptor made by sequentially laminating a transparent insulating layer 9 and a transparent insulating layer 9 can be used.

When using the photoreceptor shown in FIG. 1, it is desirable that the charge injected from the transparent electrode 2 into the photoconductor layer 4 when no light is irradiated is less than the charge generated by light irradiation. The present invention utilizes the fact that the effective mobility of positive and negative charges generated in the photoconductor layer by light irradiation when moving through the photoconductor layer differs depending on the polarity.

This will be explained in detail below using the drawings. FIG. 2 shows how an electrostatic latent image is formed when a photoreceptor comprising, for example, an N-type photoconductor layer 4 having the structure shown in FIG. 1A is used.

According to the present invention, optical information is irradiated from both sides of the photoreceptor while applying AC corona discharge to the photoreceptor using an AC corona discharger 10 or the like. First, to explain the area A that is irradiated with only the light 12 of the first optical information, positive and negative charges are generated in the vicinity of the photoconductor layer 4 in contact with the transparent insulator layer 5 due to the light irradiation. . During the negative half-wave of AC corona discharge, negative charges among the charges generated by the light irradiation move in the photoconductor layer 4 toward the transparent charge injection blocking layer 3, and the photoconductor layer 4 The interface in contact with the transparent charge injection blocking layer 3 is captured nearby. On the other hand, in the case of a positive half wave, the positive charge receives a force from the electric field toward the transparent charge injection blocking layer, but N
In a type photoconductor, positive charges hardly move because their effective mobility is lower than that of negative charges. As a result, with each negative half-wave, negative charges increase at or near the interface of the photoconductor layer 4 in contact with the transparent charge injection blocking layer 3. At this time, the transparent insulating layer 5
The surface of is charged with a negative charge 14. On the other hand, in the region C where only the second optical information light 13 is irradiated, positive and negative charges are generated in the vicinity of the photoconductor layer 4 in contact with the charge injection blocking layer 3 . In this case, negative charges increase at and near the interface of the photoconductor layer 4 in contact with the transparent insulating layer 5 for each positive half-wave of the AC corona discharge, and at this time, the surface of the transparent insulating layer 5 has a positive charge of 18 is charged with electricity. On the other hand, in the area B where both the first and second optical information lights were irradiated and the area D where neither of the lights were irradiated, the positive and negative half-waves of the corona discharge are charged to the same degree, so positive and negative charges are generated. cancel each other out, and there is almost no charge on the surface of the transparent insulating layer 5. Next, the entire surface of the photoconductor layer 4 is irradiated with light to extinguish the internal electric field of the photoconductor layer 4, so that the transparent electrode 2 is oriented in a direction corresponding to the light irradiated part of the optical information, as shown in the opening of FIG. And an electrostatic latent image with a negative potential is obtained. When using a photoconductor that uses a P-type photoconductor, the actual mobility of positive charges is higher than that of negative charges, so everything is the opposite of when using an N-type photoconductor as described above. An electrostatic latent image is obtained using charges of polarity.

When a photosensitive plate having the structure shown in FIG. 1 is used, an electrostatic latent image is formed by the same means.

For example, FIG. 3 shows an example in which a photoreceptor comprising an N-type photoconductor layer 8 is used. Apply an AC current to the photoreceptor using an AC corona discharger 10 or the like. Optical information is irradiated from both sides of the photoreceptor while applying a discharge. At this time, in the area A where only the first optical information light 26 is irradiated, positive and negative charges are generated in the vicinity of the photoconductor layer 8 in contact with the transparent insulator layer 9 due to edge irradiation. Since positive charges have a lower effective mobility than negative charges, negative charges flow into the transparent electrode every negative half-wave, and during positive half-waves, almost no positive charges move. Therefore, positive charges 29 increase at or near the interface of the photoconductor layer 8 in contact with the transparent insulator layer 9, and the surface of the transparent insulator layer 9 is charged with negative charges 28. In addition, in the region C where only the second optical information light 27 is irradiated, negative charges 32 increase at and near the interface of the photoconductor layer 8 in contact with the transparent insulator layer 9, contrary to the region A, and positive charges 32 increase. Charge flows into the transparent electrode 7. As a result, the surface of the transparent insulating layer 9 is charged with positive charges 31. On the other hand, in the area B where both the first and second optical information lights were irradiated and the area D where neither was irradiated, the positive and negative half-waves are charged to the same degree, so the positive and negative charges are canceled out. Transparent insulator layer 9
There is almost no charge on the surface. Next, the entire surface of the photoconductor layer 8 is irradiated with light to extinguish the internal electric field of the photoconductor layer 8, so that the transparent electrode 7 is oriented in a direction corresponding to the light irradiated part of the optical information, as shown in the opening of FIG. And an electrostatic latent image with negative potential is obtained. Also in the photoreceptor having this structure, when a P-type photoconductor is used, an electrostatic latent image is obtained due to charges of polarity completely opposite to that when the above-mentioned N-type photoconductor is used.

The electrostatic latent images of positive and negative polarity formed by the above method are developed by developing means such as the cascade method, magnetic brush method, powder cloud method, etc. The toner particles are developed to form a toner image, which is then transferred to a recording medium such as paper.

Next, the image is fixed by heating, pressure, a solvent, etc. to obtain an image. After the transfer, the toner particles remaining on the surface of the transparent insulating layer 9 are removed and static electricity is removed, so that the transparent insulating layer 9 can be used again. FIG. 4 shows a schematic diagram of a first embodiment of a recording device according to the invention.

This apparatus uses a photosensitive drum 101 in which various layers are laminated as shown in FIG. 1A on a hollow cylindrical transparent support base such as glass or resin. This device includes the photoreceptor drum 101, an AC corona discharger 102, and means 1 for irradiating optical information from the outside and inside of the photoreceptor drum 101.
03, 104, an exposing device 105 for exposing the entire surface of the photoreceptor drum 101, a developing means 106 for developing two types of electrostatic latent images, positive and negative, with two types of toner particles of different sacrifices, and a toner. An image is stored on a recording medium 108 such as paper.
a transfer means 107 for transferring the toner image onto the recording medium 108, a fixing means 109 for fixing the toner image transferred onto the recording medium 108, and a cleaning means 110 for removing toner particles remaining on the surface of the photoreceptor drum 101 after the toner image has been transferred. and a discharging means 111 for erasing electrostatic latent images on the surface of the insulating layer of the photosensitive drum and inside the light guide layer. The order of cleaning means 110 and static eliminating means 111 may be reversed, or cleaning and static eliminating may be performed simultaneously. Photosensitive drum 1
01 rotates and passes through each part in turn. The cleaned and neutralized photosensitive drum 101 is irradiated with optical information by the first and second optical irradiation means 103 and 104 while being subjected to AC corona discharge by the AC corona discharger 102, and then exposed to light by the exposure means 105 over the entire surface. As a result, two types of electrostatic latent images having positive and negative characteristics are formed on the surface of the photoreceptor drum 101 as described above. This entire surface exposure can be made more effective by performing it from the inside and outside of the photoreceptor drum. A toner image is formed from these electrostatic latent images by a one-bath development method or a two-bath development method using toner particles of opposite signs using a cascade method, a magnetic brush method, a powder cloud method, or the like. These toner images are transferred onto a recording medium such as paper by a transfer means 107 using electrostatic force, adhesive force, or the like. As this transfer means, for example, toner particles of different polarities are charged to the same polarity using a corona charger or the like, and then a toner image of different polarities is transferred to the recording medium by pressing the recording medium against the toner image using a ground roller or the like. Can be transferred well. and heat rollers, heat plates, infrared heaters,
A fixing means 109 fixes this toner image onto a recording medium using a pressure roller or the like to obtain a recording. Toboo particles remaining on the photosensitive drum 101 after transfer are removed by a cleaning means 110, such as a brush or a blade, and are neutralized by a deburring means 111 and used again to form a latent image. As the disarming means 111, the photosensitive drum 10
AC corona charging may be performed while irradiating light onto 1. Next, FIG. 5 shows a schematic diagram of a second embodiment of the recording device. This apparatus uses a photoreceptor film 112 in which each layer is laminated as shown in FIG. The film 112 is conveyed by a conveying means such as a lo-fu 113 or the like. Other latent image formation, development, transfer, fixing, cleaning, and charge removal are performed in the same manner as in the first embodiment. In this embodiment, since the photoreceptor film 112 is used, optical information can be easily irradiated. In this way, this printer can produce two-color recording with a configuration comparable to that of a secondary recording device.

Further, since continuous recording is possible, two-color recording can be obtained even on a roll-shaped recording medium.

[Brief explanation of drawings]

Figure 1 shows the structure of the photoreceptor used in the present invention, Figure 2 shows the structure of the photoreceptor used in the present invention.
The figure is an explanatory diagram of the electrostatic charge latent image forming method when using the photoreceptor with the structure shown in Fig. 1A, and Fig. 3 shows the electrostatic charge when using the photoreceptor with the structure shown in Fig. 1B. FIG. 4 is a schematic diagram for explaining the first embodiment of the recording device according to the present invention, and FIG. 5 is a schematic diagram for explaining the second embodiment of the recording device according to the present invention. FIG. In the figure, 1 and 6 are transparent support bases, 2 and 7
3 is a transparent electrode, 3 is a transparent charge injection blocking layer, 4 and 8 are photoconductor layers, 5 and 9 are transparent insulator layers, 1 is an AC corona discharger, 1 is an AC power supply, 12 is a first Optical information light, 13 is second optical information light, 14 and 22 are negative charges charged on the transparent insulating layer, 15, 20, 22
, 25, 29 and 34 are positive charges in the photoconductor layer, 1
6, 19, 23, 24, 32, and 35 are negative charges in the photoconductor layer, 17 and 33 are positive charges transmitted through the transparent electrode, and 18 and 31 are charged on the transparent insulator layer. 21 and 30 are negative charges induced in the transparent electrode, 26 is the light of the first optical information, 27 is the light of the second optical information, 101 is the photoreceptor drum, and 102 is the AC coil. 103 and 104 are optical information irradiation means;
05 is an exposure device, 106 is a developing means, 107 is a transfer means,
108 is a recording medium, 109 is a fixing means, 110 is a cleaning means, 111 is a static eliminating means, and 112 is a photoreceptor film. Figure 5 Eagle r Figure Tsutomu ≧ Z Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A photoconductor having different electric conductivities for holes and electrons, and in which photoelectric liberation of electrons and holes occurs in a surface layer of the photoconductor that is irradiated with light. Using a photoreceptor with a multilayer structure including at least a conductor, a transparent electrode, and a transparent insulator, a first optical image is obtained from one surface of the photoreceptor,
After positive and negative corona charging is performed on one surface of the photoreceptor while irradiating a second optical image from the other surface, the first and first surfaces are irradiated with light over the entire surface of the photoreceptor. An image forming method characterized by sensing two types of electrostatic latent images having positive and negative polarities corresponding to two optical images. 2. The image forming method according to claim 1, wherein a photoreceptor having a multilayer structure is used instead of sequentially laminating at least a transparent electrode body, a photoconductor layer, and a transparent insulator layer. 3. The image forming method according to claim 1, which uses a photoreceptor having a multilayer structure in which at least a transparent electrode, a transparent charge injection blocking layer, a photoconductor layer, and a transparent insulator layer are successively laminated.