JPH0688424B2 - Electrophotographic recording device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrophotographic recording device used in a copying machine, a printer, a facsimile, and the like.

[Prior Art] As an electrophotographic recording apparatus, one using a so-called Carlson process has been widely put into practical use, but in recent years, an apparatus having a recording principle different from the above-mentioned Carlson process has also been studied.

Examples of the recording method by the non-Carlson process include those described in Japanese Patent Application No. 63-161307 and drawings.

This recording method will be described below.

In FIG. 3, 1 is a first support having a light-transmitting property, 2
Is a second support placed opposite to the first support, 3 is a back electrode formed on the first support, 4
Is a photosensitive layer formed on the back electrode 3, 5 is a surface electrode partially formed on the photosensitive layer 4, 6 is a charging electrode formed on the second support 2, and 7 is a light source. , 8 is a recording medium installed between the first support 1 and the second support 2, 21 is toner, and 21a is a toner image formed on the recording medium 8 by the flight of the toner 21. Is.

The back electrode 3, the surface electrode 5, and the charging electrode 6 have a first potential V1, a second potential V2, and a third potential V3, respectively.
Is kept at.

FIG. 6A shows a state when light is not irradiated (hereinafter, referred to as dark time).

The portion of the photosensitive layer 4 where the surface electrode 5 is not formed (hereinafter,
It is called the photosensitive layer surface. 2), the resistance components Rvd and surface resistance Rsd in the laminating direction of the photosensitive layer 4 can be divided into resistance components. By appropriately selecting the resistivity and film thickness of the photosensitive layer 4 and the distance of the portion where the surface electrode 5 is not formed, and Rvd >> Rsd, the surface potential of the surface of the photosensitive layer 4 is approximately the potential of the surface electrode 5. It is equal to V2. Therefore
The value of V2 and V3 is selected appropriately, and the potential V3 of the charging electrode 6
The electric field generated by the potential difference (~ | V3 ~ V2 |) between the surface potential (~ V2) and the surface potential (~ V2) is set to a predetermined electric field or less, and the toner 21 and the charging electrode 6 are attached more than the Coulomb force acting on the toner 21 by the electric field. Toner 21 can be
Never jumps out.

FIG. 2B shows a case where light is irradiated (hereinafter referred to as light).
It shows the state of.

When the light from the light source 7 is irradiated from the back surface side of the first support 1 to the photosensitive layer 4 in the portion where the surface electrode 5 is not formed, photocarriers are generated in the photosensitive layer 4 in this portion. , The resistance value in the stacking direction decreases to Rvp. On the other hand, the surface resistance value Rsp hardly changes. That is, Rvp << Rvd, R
It can be thought of as sp ~ Rsd. If the resistivity of the photosensitive layer 4 at the time of light irradiation is an appropriate value, it is possible to set Rvp << Rsp.
Becomes equal to the potential V1 of. Therefore, by appropriately selecting the value of V1, the electric field generated by the potential difference (~ | V3 ~ V1 |) between the potential V3 of the charging electrode 6 and the surface potential (~ V1) is set to a predetermined electric field or more, and If the Coulomb force acting on the toner 21 is made larger than the adhesive force between the toner 21 and the charging electrode 6, the toner 21 leaves the charging electrode 6 and flies toward the recording medium 8 to form a toner image on the recording medium 8. 21a is formed.

When actually displaying characters or figures in dots,
A photosensitive layer or the like is formed in a line shape, and a toner image is formed for each dot for dot display.

[Problems to be Solved] In the above-described conventional recording apparatus, when the distance between the light source and the photosensitive layer is displaced due to the warp of the first substrate or the like, the irradiation range of the light irradiated on the photosensitive layer may be expanded. . Therefore, the dots due to the toner image may become large or the peripheral edge of the dots may be blurred, resulting in a decrease in resolution.

An object of the present invention is to provide an electrophotographic recording device with good resolution.

[Means for Solving the Problems] In the present invention, a light-shielding film formed so as to surround the light-transmitting portion is provided, or a back-light-shielding rear electrode formed so as to surround the light-transmitting portion is provided, Light is irradiated to a certain area of the photosensitive layer through these light transmitting portions.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 shows a first embodiment of the present invention.

In the figure, 1 is a first support having a light-transmitting property, 2 is a second support installed to face the first support,
3 is a light-transmissive back electrode formed on the upper part of the first support, 4 is at least a photosensitive layer formed on the back electrode 3, and 5 is a surface partially formed on the photosensitive layer 4. An electrode, 6 is a charging electrode formed on the second support 2,
Reference numeral 7 is a light source, and 8 is a recording medium installed between the first support 1 and the second support 2. The back electrode 3, the surface electrode 5, and the charging electrode 6 have a first potential V1 and a second potential V2, respectively.
Of the electric potential V2 and the third electric potential V3. These are basically the same as the above conventional example. That is, in this example, the basic recording principle is the same as in the conventional example. Reference numeral 11 denotes a conductive floating electrode provided on the photosensitive layer 4, which is disclosed in Japanese Patent Application No. 63-63
As described in the specification of No. 161307, the resolution of each dot by the toner image is improved. Reference numeral 9 is a light-shielding film formed on the first support body so as to surround the translucent portion 9a. The light shielding film 9 blocks the light from the light source 7, and the translucent portion 9a transmits the light from the light source 7. That is, the light-shielding film 9 and the light-transmissive portion 9a are appropriately determined according to the wavelength of the light of the light source 7. For example, a metal film may be used for the light-shielding film 9, and the light-transmitting portion 9a may be formed by opening the metal film. Reference numeral 12 is an insulating layer formed on the light-shielding film 9 and electrically insulates the light-shielding film 9 from the back electrode 3 or the photosensitive layer 4 when the light-shielding film 9 is made of a conductive material. Is. Therefore, when the light shielding film 9 is made of an insulating material, the insulating layer 12
Is not always necessary.

Note that, in FIG. 1, the light-shielding film 9 and the insulating layer 12 are drawn spatially separated, but this is for the purpose of making it easier to see each component for the sake of description. It is in close contact with 12.

In this example, it is important to match the positional relationship between the light source 7 and the translucent portion 9a so that the light from the light source 7 is sufficiently transmitted through the translucent portion 9a. In addition, the light source 7 transmitted through the translucent portion 9a
Accurately irradiating the floating electrode 11 with light from is also important for improving the resolution.

Each component on the first support is preferably formed by a thin film forming technique such as a vapor deposition method or a vapor phase growth method and a photolithography technique. By using the photolithography technique, the translucent portion 9a and the floating electrode 11 can be accurately aligned.

In this example, since the light shielding film 9 is provided, the photosensitive layer 4 is irradiated with only the light transmitted through the translucent portion 9a, so that the irradiation range of the light with which the photosensitive layer 4 is irradiated does not expand. As a result, the dots formed by the toner image do not become large and the peripheral portions of the dots do not become blurred, and the resolution is greatly improved.

Further, if each component on the first support is formed by the photolithography technique, the translucent portion 9a and the floating electrode 11 can be accurately aligned. for that reason,
Instead of aligning the light source 7 and the floating electrode 11 which has been difficult in the past, the light transmissive portion 9a and the floating electrode 11 may be aligned.
Can be accurately aligned with.

Embodiment 2 FIG. 2 shows a second embodiment of the present invention.

This example is an improvement of the back electrode of the above conventional example,
The basic recording principle is the same as that of the conventional example. Therefore,
In FIG. 2 and FIG. 3 showing the conventional example or FIG. 1 showing the first embodiment, the same reference numerals indicate the same things.

In FIG. 2, the first support 1 and the back electrode 3 and the photosensitive layer 4 are illustrated as being spatially separated, but this is for the purpose of making each component easy to see for the sake of description. The first support 1 and the back electrode 3 are in close contact with the photosensitive layer 4.

In this example, the back electrode 3 has a light shielding property and is formed so as to surround the translucent portion 3a. The back electrode 3 having a light blocking property blocks the light from the light source 7, and is a transparent part.
Reference numeral 9a is for transmitting the light from the light source 7. That is,
The back electrode 3 and the transparent portion 3a are appropriately determined according to the wavelength of the light of the light source 7. For example, a metal film may be used for the back electrode 3, and the light-transmissive portion 9a may be formed by opening this metal film.

In this example, it is important to match the positional relationship between the light source 7 and the translucent portion 3a so that the light from the light source 7 is sufficiently transmitted through the translucent portion 3a. It is also important for the floating electrode 11 to be accurately irradiated with the light from the light source 7 that has passed through the transparent portion 3a in order to improve the resolution.

Each component on the first support is preferably formed by a thin film forming technique such as a vapor deposition method or a vapor phase growth method and a photolithography technique. By using the photolithography technique, the transparent portion 3a and the floating electrode 11 can be accurately aligned.

In this example, since the back electrode 3 has a light-shielding property and is formed so as to surround the translucent portion 3a, only the light transmitted through the translucent portion 3a is irradiated to the photosensitive layer 4, so that the photosensitive layer 4 is exposed. The irradiation range of the light with which the layer 4 is irradiated is not expanded. As a result, the dots formed by the toner image do not become large and the peripheral portions of the dots do not become blurred, and the resolution is greatly improved.

Further, if each component on the first support is formed by the photolithography technique, the transparent portion 3a and the floating electrode 11 can be accurately aligned. for that reason,
Instead of aligning the light source 7 and the floating electrode 11 which has been difficult in the past, the light transmissive portion 3a and the floating electrode 11 may be aligned.
Can be accurately aligned with.

[Effect] According to the present invention, a light-shielding film formed so as to surround the light-transmitting portion is provided, or a light-shielding back electrode formed so as to surround the light-transmitting portion is provided. Since light is irradiated to a certain area of the photosensitive layer through the characteristic portion, it is possible to prevent the irradiation range of the light irradiated to the photosensitive layer from expanding.
Therefore, it is possible to prevent the dots of the toner image from becoming large and the peripheral portions of the dots from blurring, and it is possible to significantly improve the resolution.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention, FIG. 2 is a perspective view showing a second embodiment of the present invention, and FIG. 3 is an explanatory view showing a conventional example. 1 ... First support 2 ... Second support 3 ... Back electrode 3a ... Translucent part 4 ... Photosensitive layer 5 ... Surface electrode 6 ... Charging electrode 7 ... Light source 8 ... Recording medium 9 ... Shading film 9a ... Translucent part 21 ... Toner 21a ... Toner image V1 ... First potential V2 ... Second potential V3 ... Third potential

Claims (2)

[Claims] 1. A first support having a light-transmitting property, a second support facing the first support, and a surface of the first support facing the second support. A translucent back electrode formed on the side and held at a first potential, and a second surface region formed at least on the back electrode and spaced from the first surface region and the first surface region. And a light-shielding film formed between the first support and the photosensitive layer, the light-shielding film being formed so as to surround the light-transmitting portion provided corresponding to the first surface region. A surface electrode formed on the second surface region of the photosensitive layer and held at a second potential, and formed on a surface of the second support opposite to the first support, The charging electrode held at a third potential and the first side of the first support through the light-transmitting portion from the back side of the first support. A light source that emits light to a region corresponding to the first surface region, wherein the absolute value of the difference between the first potential and the third potential is larger than a predetermined potential difference, and the second potential is When the first, second, and third potentials are set such that the absolute value of the difference from the third potential is smaller than a predetermined potential difference, and the light is applied to the photosensitive layer, The potential of the first surface region of the photosensitive layer in the portion irradiated with the light is set to a potential substantially equal to the potential of the back electrode, and when the light is not emitted to the photosensitive layer, the photosensitive layer is exposed. The potential of the first surface region is set to be substantially equal to the potential of the surface electrode, and when the light is irradiated on the photosensitive layer, the light-irradiated portion of the photosensitive layer is The toner on the first surface area is ejected toward the charging electrode. The Rukoto, electrophotographic recording apparatus characterized by forming a toner image on the recording medium between the first support and the second support. 2. A first support having a light-transmitting property, a second support facing the first support, and a surface of the first support facing the second support. A light-shielding back electrode formed on the side so as to surround the light-transmitting portion and held at a first potential; and a first electrode formed on at least the back electrode and corresponding to the light-transmitting portion. A photosensitive layer having a first surface region and a second surface region separated from the first surface region; and a surface electrode formed on the second surface region of the photosensitive layer and held at a second potential. And a charging electrode formed on the surface of the second support facing the first support and held at a third potential, and the translucency from the back side of the first support. A light source for irradiating light to a region corresponding to the first surface region of the photosensitive layer through a portion, the first potential The absolute value of the difference between the second potential and the third potential is larger than a predetermined potential difference, and the absolute value of the difference between the second potential and the third potential is smaller than the predetermined potential difference. When the first, second and third electric potentials are set and the photosensitive layer is irradiated with the light, the electric potential of the first surface region of the photosensitive layer in a portion irradiated with the light is set to the first electric potential. The potential of the first surface region of the photosensitive layer is set to be substantially equal to the second potential when the light is not applied to the photosensitive layer. When the photosensitive layer is irradiated with the light, the toner on the first surface region of the photosensitive layer in a portion irradiated with the light is caused to fly toward the charging electrode, whereby the first Image on the recording medium between the second support and the second support. Forming an electrophotographic recording apparatus, characterized by.