JPH0527564A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent reflection which is repeated inside a light transmissive supporting body and to obtain a high-quality exposed image by bringing a light transmissive material whose refractive index, at least, is larger than that of air into contact with the back surface side of the light transmissive supporting body. CONSTITUTION:A photosensitive drum 1 is formed by laminating a light transmissive electrode layer 1b and a photoconductive layer 1c on the drum-like light transmissive supporting body 1a and constructed so that it can rotate in a direction shown by an arrow. The light transmissive material 4 is sealed in the photosensitive drum 1 in which an exposing unit 3 is inserted. As for the light transmissive material 4 which is brought into contact with the rear surface side of the light transmissive supporting body 1a positioned on the exposing unit 3 side, the material whose refractive index is larger than that of the air, at least, is desirable, and the material whose refractive index is equal to or above that of the light transmissive supporting body 1a is more desirable, for example, silicone resin for sealing an IC is sealed in the drum and then hardened so that the resin may be rotated integrally with an exposing head 2 so as to contact and slide on the inner peripheral surface side of the photosensitive drum 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a photosensitive drum, a photosensitive belt or other photosensitive member having an exposing means incorporated therein, and in particular, exposure by reflection of an exposure image of a light-transmitting support constituting the photosensitive member. An object of the present invention is to provide an image forming apparatus capable of preventing a decrease in image sharpness.

[0002]

2. Description of the Related Art Conventionally, for example, in a photosensitive drum formed by laminating a transparent electrode layer and a photoconductor layer on a transparent support,
An exposure head for generating a light output corresponding to image information is inserted, and the light output of the exposure head is focused to form a latent image on the photoconductor layer. An image forming apparatus is known in which after the latent image is formed into a toner image through the developing means, the toner image can be transferred onto plain paper through a transfer roller or other transfer means. (JP-A-58-44445, etc.)

[0003]

Since the light-transmitting support used in this type of image forming apparatus is formed by using a cylindrical glass body or resin body, the refractive index is larger than that in air. On the other hand, if there are substances with different refractive indices, such as air and water, or air and glass, even if both are transparent, the refractive index will be When light is incident from a substance having a high intensity to a substance having a low intensity, partial reflection or total reflection occurs corresponding to the incident angle.

For this reason, for example, as shown in FIG. 1B, after the exposure image optically output from the LED 22, EL or the like constituting the exposure means 2 passes through the air and enters the translucent support 1a. , The photoconductive layer 1 through the translucent electrode layer 1b (hereinafter, the translucent support and the translucent electrode layer are referred to as translucent substrate).
However, since the conductive layer 1c is non-transparent, it is reflected at the boundary with the transparent substrate, and the reflected light is transmitted. Optical support 1a
As the beam width is expanded by repeating reflection inside, the exposure image is repeatedly formed on the photoconductor layer 1c.
Even if the focal length is accurately adjusted by the focusing lens 23, the exposed print line width is enlarged and a predetermined print line width cannot be obtained, which not only causes deterioration of print quality, but also It becomes impossible to express precision characters such as crushing, blurring and other intermediate density.

An object of the present invention is to provide an image forming apparatus capable of suppressing the repeated reflection between the translucent support and the air layer as much as possible, thereby preventing a decrease in the sharpness of an exposed image and a decrease in the print quality. is there.

[0006]

According to the present invention, a translucent substance having a refractive index higher than that of at least air, more preferably a translucent substance having a refractive index equal to or higher than that of the translucent support. It is characterized in that the photo-sensitive material is brought into contact with the back surface side of the transparent support located on the exposure means side.

[0007]

As described above, in the image forming apparatus, the LE
An exposure image optically output from D, EL or the like is incident on the light-transmissive support to form an exposure latent image on the photoconductor layer, and then reflected at the boundary with the light-transmissive support, The reflected light is repeatedly reflected inside the translucent support. In the present invention, however, the incident side (rear side) of the support has a refractive index equal to or higher than that of the translucent support. Since the light-transmitting substance that is contained therein is in contact with the light-transmitting substance, it is emitted to the light-transmitting substance side as it is without being reflected inside the support, and it is possible to prevent deterioration of printing quality due to the repeated reflection.

In this case, if the refractive index of the translucent material is not more than the refractive index of the support but not less than the refractive index of air, the repetitive reflection is reduced and the deterioration of print quality can be suppressed. In this case, an air layer may be interposed between the light-transmitting substance and the exposing means. However, with this structure, the light output from the exposing means is attenuated at the interface between the air layer and the light-transmitting substance. Therefore, it is preferable to interpose the light-transmitting substance in the entire area between the exposing means and the transparent support.

The transparent substance may be a solid, jelly-like substance or fluid, and may be a thin film. For example, when the photoconductor is formed of a photoconductor drum, a viscous substance is used in the drum. It is preferable that the light-transmitting substance composed of a fluid is enclosed so that there is no boundary friction between the light-transmitting substance and the exposure head forming the exposure means.

[0010]

Embodiments of the present invention will now be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely examples, unless otherwise specified. Not too much.

FIG. 1A shows the overall structure of an image forming apparatus according to an embodiment of the present invention. Reference numeral 1 is a photosensitive drum, which is a drum-shaped transparent support 1a and a transparent electrode layer 1b. The photoconductor layer 1c is formed by stacking and is rotatable in the arrow direction. The transparent support 1a is made of glass,
In addition to inorganic materials such as quartz and sapphire, transparent resins such as fluororesin, polyester, polycarbonate, polyethylene and epoxy are used.

For the transparent electrode layer 1b, a transparent conductive material such as ITO (indium / tin / oxide), tin oxide, lead oxide or indium oxide is formed as a thin film on the support 1a. The photoconductive layer is made of a-Si, and the transparent electrode layer 1
A film is formed on b by glow discharge decomposition method, sputtering method, or the like.

On the other hand, 2 is an exposure unit inserted in the photosensitive drum 1, which is a support made of a non-translucent insulating material.
LED array 2 that produces light output corresponding to image information on 21
2 and focusing lens 23 (trade name: SELFOC lens)
Is extended and fixed over the entire axial direction. The image forming position of the exposure system is formed so as to form an image on the photoconductor layer 1c positioned on the focal line connecting the photosensitive drum 1 and the developing sleeve 3 described later.

Reference numeral 3 denotes a developing sleeve containing a fixed magnet assembly, and by rotating the sleeve 3 in the direction of the arrow, the toner in the toner container 31 is exposed to the exposure system 22-2.
It is configured to be guided to the developing position corresponding to the image forming position of No. 3. The photosensitive drum 1 and the developing sleeve 3 are configured to be rotatable in opposite directions at a rotational speed that causes a relative speed difference. Then, in the photosensitive drum 1 in which the exposure unit 3 is inserted, the transparent substance 4 which is the gist of the present invention is provided.
Is enclosed.

As described above, it is preferable that the translucent substance 4 has a refractive index at least larger than that of air, preferably equal to or higher than that of the translucent support 1a. For example, a silicon resin for IC encapsulation. Alternatively, the resin may be sealed in the drum and then cured, and the resin may rotate integrally with the exposure head 2 by sliding in contact with the inner peripheral surface of the photosensitive drum 1.
Further, the translucent substance 1a may be enclosed in the drum 1 in a fluid state without being cured. In this case, the fluid translucent substance is preferably an insulating fluid in order to prevent electric leakage or leak at the contact portion of the exposure unit 2 or the like, and for example, Fluorinert, alcohol, oil or the like can be used.
When the contact portion is covered with an insulating material, it is possible to use, for example, water whose viscosity is adjusted by mixing glycerin. In this case, in order to prevent liquid leakage, the fluid preferably has a predetermined viscosity, for example 100
It is better to set it below CPS.

FIG. 2 shows a sealing structure in which a fluid is used as the translucent material 4, and 5 is a fixed shaft for supporting the exposure head at both ends of a housing (not shown). The end is D-cut, and the D-cut portion 5a is used for positioning. 10 is a gear integrated with the photosensitive drum, 11
Is a bearing bearing arranged at both ends of the drum, and is configured to rotate the photosensitive drum 1 in a predetermined direction while holding the exposure unit 2 in position via a fixed shaft 5 by a drive system (not shown). ing.

An oil seal 12 is interposed between the bearing 11 and the drum 1, and the bearing 11 and the drum 1 are arranged.
The inner circumference is configured to be liquid-tightly sealed. Instead of adopting the above configuration, as shown in FIG. 3, the fixed shaft 5 and the drum 1 may be directly liquid-tightly sealed by only the oil seal 13. In this case, the oil seal 13 and The sliding bearing 14 fixed to the fixed shaft 5 is disposed adjacent to the side,
The drum 1 may be rotatable while the exposure unit 2 is fixed in position by the slide bearing 14 via the fixed shaft 5.

FIG. 4 shows another embodiment in which the EL head 6 is used. The light emitting head 6 in which EL light emitting elements are arranged in rows is directly contacted with the inner peripheral surface of the drum 1 and is adjacent to the light emitting head 6. A liquid translucent substance applicator 8 which also functions as a lubricant is disposed, and the thin film translucent substance 4 is interposed between the surface of the light emitting head 6 and the inner peripheral surface of the drum 1 by the applicator 8. In the figure, 15 is a transfer device, 16 is a fixing device, and 17 is plain paper for transferring a toner image.

[0019]

As described above, according to the present invention, the transparent support 1a is brought into contact with the rear side of the transparent support 1a by a transparent substance having a refractive index higher than that of air.
It is possible to obtain a high quality exposure image by preventing repeated reflection inside.

[Brief description of drawings]

FIG. 1A is a basic configuration diagram of the present invention, and FIG. 1B is an enlarged view of a main part of an image forming apparatus of the related art.

FIG. 2 shows an internal structure of a photosensitive drum according to an exemplary embodiment of the present invention.

FIG. 3 shows a modified example of the sealing portion of FIG.

FIG. 4 shows another embodiment of the present invention using an EL head.

[Explanation of symbols]

1 photoconductor drum 1a translucent support 1c Photoconductive layer 2 Exposure means 4 Translucent material

Claims (4)

[Claims] 1. A photoconductor comprising a photoconductive layer having a photoconductive layer directly or indirectly formed on the surface side of a translucent support, said photoconductive layer being provided by an exposing means arranged on the back side of the photoconductive layer. An image forming apparatus capable of forming an exposure image on a surface thereof, wherein a transparent substance having a refractive index at least higher than that of air is brought into contact with the rear surface side of the transparent support on the exposure means side. . 2. The image forming apparatus according to claim 1, wherein the translucent substance is a translucent substance having a refractive index that is the same as or higher than the refractive index of the translucent support. 3. An image forming apparatus, wherein the translucent material is interposed between an exposing means and a transparent support. 4. The image forming apparatus according to claim 1, wherein the photoconductor is formed of a photoconductor drum, and a translucent substance made of a viscous fluid is enclosed in the drum.