JPS5918702B2 - Electrophotographic method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photosensitive plate provided with an injection blocking layer having photoconductivity and a novel electrophotographic method using the electrophotographic photosensitive plate.

FIG. 1 shows a conventional electrophotographic photosensitive plate 4 (hereinafter referred to as photosensitive plate).
The cross-sectional structure and normal usage are shown. A photosensitive plate 4 is composed of a conductive electrode 1, a photoconductor layer 2, and a surface insulator layer 3. Charging of the photosensitive plate 4 by the corona charger 5 and irradiation of the recording image light 6 are both performed from the surface insulator layer 3 side. In such a configuration, in the case of a conventional photosensitive plate 4 that requires simultaneous charging and exposure, the recording image source T cannot be brought into close contact with the photosensitive plate 4 due to the presence of the charger 5, resulting in optical loss. It was the cause. In order to solve this problem, FIG. 2 shows a structure in which only the conductive electrode 1 of the conventional photosensitive plate 4 is replaced with a transparent conductive electrode 8, and recording image light 6 is irradiated onto the photosensitive plate 4 from the side opposite to the charger 5. In this example, the transparent conductive electrode 8 and the photoconductor layer 2 are in direct contact with each other, and the photosensitive plate 4 has a surface insulator layer 3 on which it is exposed. When forming a charge image, since a high voltage of about 1000 to 2000 (V) is effectively applied by the corona charger 5, the photoconductor layer 2 is
Injection of majority carriers into the recording image light 6 occurs even in dark areas, regardless of the presence or absence of the recording image light 6.

Therefore, the injected carriers in the dark area are induced in the surface insulating layer 3 as background charges in the dark area, so that the S/N of the recorded image decreases.
significantly decreases This disadvantage is caused by the transparent conductive electrode 8
This occurs because the photoconductor layer 2 and the photoconductor layer 2 are in direct contact with each other. This invention eliminates these drawbacks, significantly reduces the background of the charge image formed on the surface insulator layer 3 that is not affected by recording image light, and makes it possible to obtain a recorded image with a good S/N ratio. The present invention provides a photographic photosensitive plate and an electrophotographic method using the same. FIG. 3 shows a basic structural diagram of a photosensitive plate used in the electrophotographic method according to the present invention.

That is, the photoreceptor 11 of the present invention includes a transparent support 9, a transparent conductive electrode 8, a photoconductive injection blocking layer 10, and a photoconductor layer 2.
It has a five-layer structure including a surface insulating layer 3 and a surface insulating layer 3.
For convenience of explanation, only the case where the surface insulating layer 3 made of polyethylene terephthalate is used as the surface layer will be described in detail below. Further, although many changes are possible for each of the other elements of the photoreceptor 11, the transparent support 9
Polyethylene terephthalate is used as the transparent conductive electrode 8, copper iodide or indium oxide layer is used as the transparent conductive electrode 8, and polyvinyl carbazole (PV) is used as the photoconductive injection blocking layer 10.
K) will be explained in detail with respect to the case where a selenium-tellurium alloy vapor deposited layer is used as the photoconductor layer 2. The most important component of the electrophotographic photosensitive plate of the present invention having the structure shown in FIG. 3 is the photoconductive injection blocking layer 10 provided between the transparent conductive electrode 8 and the photoconductor layer 2. An electrophotographic method using a photosensitive plate 11 provided with this photoconductive injection blocking layer 10 will be explained with reference to the basic process diagram of FIG. First, in FIG. 4A, a negative corona charger 14 consisting of a thin corona wire 13 and a guard electrode 12 is placed on the side of the surface insulating layer 3 of the photosensitive plate 11. On the other hand, recording image light 6 is irradiated from the transparent support 9 side. Here again, the photoconductive injection blocking layer 10 has a sufficiently low concentration of majority carriers compared to the photoconductor layer 2Vc, and prevents injection of majority carriers from the transparent conductive electrode 8 into the photoconductor layer 2 in the dark. The PVK used in this example is a typical example of such a material. The thickness of the photoconductive injection blocking layer 10 is such that it can prevent the injection of majority carriers (holes in the case of selenium and tellurium alloys) from the transparent conductive electrode 8 to the photoconductor layer 2 due to the tunnel effect. Here, it is selected to be 0.1 micron or more.

There is no clear limit on the maximum thickness, and it is determined in relation to the surrounding systems such as the photoconductor layer 2 and the surface insulator layer 3, but an appropriate thickness for manufacturing is 1 to 20 microns. The maximum thickness is preferably 50 microns or less. or,
By making the thickness of the photoconductive injection blocking layer 10 thinner than the thickness of the surface insulating layer 3, the potential of the surface insulating layer 3, which has excellent charge retention ability, can be increased, and the recording density is mainly controlled by the surface insulating layer. It can be designed so that the body layer 3 potential is determined. All embodiments of this invention include a photoconductive injection blocking layer 1
The case where the thickness of the surface insulating layer 3 is made smaller than that of the surface insulating layer 3 is shown. For convenience of explanation, a case will be described in which only the right half of the figure is irradiated with the recording image light 6.

Now, in the dark area on the left half, the photoconductive injection blocking layer 10 is used to prevent holes from being injected from the transparent conductive electrode 8 into the photoconductor layer 2 due to the corona electric field from the negative corona charger 14. This makes it possible to completely remove it. Therefore, the dark area is mainly subjected to a weak negative charge due to the dielectric polarization component, while in the irradiated area of the recording image light 6 in the right half, free holes generated in the photoconductor layer 2 by the recording image light 6 are transferred to the surface insulator. It moves to the layer 3 side by the corona electric field, and in addition to the same dielectric polarization as the dark part, a charge image is formed by an induced polarization component due to the movement of photo-generated holes on the surface insulator layer 3. Polarization due to the corona electric field occurs not only in the surface insulator layer 3, but also in
They also occur in the photoconductor layer 2 and the photoconductive injection blocking layer 10, respectively. The polarized charges on the photoconductor layer 2 are removed by exposing the entire surface of the photoconductor layer 2 to light using an exposure lamp 15 as shown in FIG. 4B.

Next, as shown in Fig. c, the charge image is transferred onto the dielectric recording paper 18 using the transfer roller 19. The dielectric recording paper 18 is the low resistance base paper 1
7 and a dielectric layer 16 are shown as a representative example. Next, as shown in figure d, the dielectric recording paper 1 to which the charge image has been transferred is
8 is developed with liquid toner in the developing section 20, and completed as a hard copy through a heating and fixing process. On the other hand, a residual charge image exists on the photosensitive plate 11, which hinders re-recording. Therefore, in order to erase the residual charge image, the photoconductive injection blocking layer 1
PVK shows photoconductivity from the 0 side. For example, while uniformly irradiating the photosensitive plate 11 with a mercury discharge lamp 21, the photosensitive plate 11 is uniformly charged with a positive corona charger 22. Through this step, the residual charge on the photoconductive injection blocker 10 is completely erased, and the surface insulator layer 3 is kept at a constant positive potential determined by the charging conditions in the positive corona charger 22. At this time, by uniformly irradiating the surface insulating layer 3 from the side of the surface insulating layer 3 with the second exposure lamp 23, equilibrium of the surface insulating layer 3 to a constant brass potential can be promoted. In this way, the photosensitive plate 11 maintained at a constant positive potential returns to the process shown in FIG. 4a again to perform rerecording. In order to take advantage of the features of the photosensitive plate 11 of the present invention whose cross-sectional structure is shown in FIG.
Irradiation direction of recording image light 6, polarity of charger, and photoconductor layer 2
It is necessary that a certain relationship be established between the conduction type of

For example, when the recording image light 6 is irradiated from the side of the transparent conductive electrode 8 as shown in FIG. When 2 is P type, the polarity of each charger is selected so that the transparent conductive electrode 2 becomes positive. When such a relationship is selected, the majority carriers generated by the recording image light can be efficiently utilized. Note that the photoconductive injection blocking layer 10 is not only made of PVK shown in the embodiment, but also has the property of blocking the injection of majority carriers from the electrode 8 into the photoconductor layer 2 in the dark, and also prevents photoconductive injection by irradiation with radiation. All materials exhibiting properties can be used.

For example, other typical examples include indefinite materials such as zinc sulfide, zinc oxide, and zinc selenide, and organic materials such as anthracene.
Moreover, many changes are possible for the photoconductor layer 2, and in addition to the selenium vapor deposited layer, a selenium-tellurium alloy vapor deposited layer, monoarsenic selenide, zinc oxide, cadmium sulfide, cadmium selenide, lead oxide, etc. , is a typical example. Further, regarding the manufacturing method, not only vapor deposition but also a powder coating layer made of an organic resin binder, a sintered layer, etc. can be used. Furthermore, the transparent support 9 can be varied in many ways, including not only polyethylene terephthalate in the embodiment of this invention, but also organic resins such as fluororesin, polyester, polycarbonate, acrylic, and polyethylene, or permanent materials such as glass. can each be used as a support. Although the thickness of the transparent support 9 is not particularly limited, when the optical fiber tube 25 is used as a recording image light source as shown in FIG. The fiber section 24 is placed in close proximity to the transparent support 9. At this time, in order to minimize the decrease in resolution of the recording image light from the optical fiber portion 24, the thickness of the transparent substrate 9 is preferably as thin as possible. For example, for applications requiring a resolution of 10 lines/Mm, 100 micron polyethylene terephthalate was used as the transparent support 9. Moreover, many changes are possible for the transparent conductive electrode 8, and indium oxide, copper iodide, a metal semitransparent vapor deposited film, etc. were used.

In addition, although the voltage applied to the charger has been explained as a positive or negative DC voltage, this means that it effectively works as a positive or negative voltage, and the voltage applied to the charger is a DC voltage that is generated in the photoconductor layer 2. Any voltage waveform that allows the majority carriers to be moved substantially in the direction of the surface insulator layer 2 can be used. For example, half-wave or full-wave rectified sine wave voltage,
Typical examples are short waveform and triangular wave voltage. As described in detail above, according to the present invention, an electrophotographic method with extremely good S/N is provided without injection of majority carriers from a transparent conductive electrode even when recording image light is applied from the transparent support side. When a single optical fiber tube is used as a recording image light source, it has the advantage that an electrophotographic apparatus with less optical loss can be provided.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the cross-sectional structure and normal usage of a conventional electrophotographic photosensitive plate, Fig. 2 is a diagram showing the configuration of a conventional electrophotographic photosensitive plate provided with transparent conductive electrodes during image formation, and Fig. 3 4 is a basic structural diagram of the photosensitive plate of this invention, FIG. 4 is a basic process diagram showing an electrophotographic method using the photosensitive plate of this invention, and FIG. 5 is a diagram of the case where a single optical fiber tube is used as a recording image light source. This is an example of this invention. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Using a photosensitive plate formed by laminating a transparent support, a transparent conductive electrode layer, a photoconductive injection blocking layer, a photoconductor, and a surface insulator layer in this order, the photosensitive plate is effectively coated from the surface insulator layer side. When a recording image light is irradiated from the transparent support side to form a charge latent image on the surface of the insulating layer while applying positive or negative corona charging to the transparent support, the photoconductive injection blocking layer acts as a carrier from the transparent electrode to the photoconductor layer. and a step of irradiating the photoconductive injection blocking layer with an electromagnetic wave that induces photoconductivity during a period after irradiation with the recording image light to release polarized charges in the photoconductive injection blocking layer. An electrophotographic method with