JPH09218549A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which is free of peeling of a photoreceptive layer, abnormal discharge of an electrifier, an image quality defect, damage to a substrate, etc., even if it is used for a long time. SOLUTION: The device is composed of an electrophotographic photoreceptor 1 with a flange 2 fitted round the opening of at least one side of its cylindrical substrate on the surface of which the photoreceptive layer is formed, a developing device having a developing roll 3 near at least one end of which a tracking roll 4 is provided, and/or a transfer device having a transfer roll. In this case, the tracking roll 4 is in contact with the periphery of the flange 2 of the electrophotographic photoreceptor by being pressed with a specific pressure, and a specific amount of gap is made between the photoreceptive layer and the developing roll and/or the transfer roll.

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 flanged electrophotographic photosensitive member which can be used in a copying machine, a laser printer, a facsimile, a printing machine and the like.

[0002]

2. Description of the Related Art In an image forming apparatus, a flanged electrophotographic photosensitive member is used in which a flange is fitted in at least one opening of a cylindrical substrate having a photosensitive layer formed by a dip coating method. In order to maintain a predetermined amount of gap between the photographic photosensitive member and the developing roll of the developing device or the transferring roll of the transferring device, at least one of the developing roll and the tracking roll provided at the end of the transferring roll is conventionally used as an electronic device. The pressing is performed on the photosensitive layer surface at the end of the photographic photoreceptor or the exposed portion of the substrate.

FIG. 3 is a view for explaining a mounting state of a flanged electrophotographic photosensitive member and a developing roll in a conventional image forming apparatus, and an electrophotographic photosensitive member having flanges 2 fitted at both ends of a cylindrical substrate. 1, a developing roll 3 provided with tracking rolls 4 near both ends is pressed by a pressing means 5, whereby the tracking roll 4 comes into contact with the photosensitive layer surface or the exposed base portion of the electrophotographic photosensitive member 1 near both ends. Then, a predetermined gap is formed between the photosensitive layer and the developing roll.

[0004]

By the way, in the conventional image forming apparatus equipped with the electrophotographic photosensitive member with the flange, when the tracking roll of the developing roll or the transfer roll is directly pressed against the surface of the photosensitive layer (see FIG. 4). , There were the following problems. In the figure, the flange 2 is fitted into the end of the cylindrical substrate 6 having the photosensitive layer 7, and the tracking roll 4 is directly pressed against the photosensitive layer 7.

(1) Since the tracking roll is pressed to a portion where the film thickness at the start of coating at the edge of the photosensitive layer is not constant, the photosensitive layer is formed when an image is formed using this flanged electrophotographic photosensitive member. It becomes impossible to keep the gap between the developing roll and the transfer roll constant,
As a result, an image with a density difference is formed in the axial direction of the electrophotographic photosensitive member with a flange. (2) The tracking roller is directly slid on the photosensitive layer, so that the photosensitive layer is worn and the drive system is slightly moved. Variation causes uneven wear, which makes it impossible to keep the gap between the photosensitive layer and the developing roll or transfer roll constant.As in the case above, the difference in density in the axial direction of the flanged electrophotographic photosensitive member (3) Peeling occurs on the photosensitive layer, and as a result,
There are problems that the image is disturbed due to biting into another drive system, the image quality is defective, and the machine malfunctions due to the abnormal discharge of the charger.

When the tracking roll of the developing roll or the transfer roll is pressed against the exposed portion of the cylindrical substrate of the electrophotographic photosensitive member with the flange for the purpose of avoiding the above-mentioned problems and preventing a difference in density between images ( (See Figure 5)
However, when forming the photosensitive layer 7, a wiping operation for forming an uncoated portion of the photosensitive layer or the like is required, which increases the manufacturing cost of the electrophotographic photosensitive member in which the flange 2 is fitted. There is also a tracking roll 4
However, there is a problem in that the base body is scratched and cannot be reused even if it is collected as a base body for an electrophotographic photoreceptor, because the base body slides on the exposed portion of the cylindrical base body 6.

Therefore, the present invention aims to remedy the above-mentioned problems in the prior art. That is, an object of the present invention is to provide an image forming apparatus which does not cause peeling of a photosensitive layer, abnormal discharge of a charger, occurrence of image quality defects, damage to a substrate, etc. even after long-term use.

[0008]

DISCLOSURE OF THE INVENTION As a result of studies by the present inventor, as a result of the fact that a portion of a developing device or a transfer device for pressing a tracking roll with a predetermined pressure is provided on the outer peripheral surface of the flange of the electrophotographic photosensitive member with a flange, The inventors have found that the above object of the invention can be achieved and completed the present invention.

According to the present invention, there is provided a developing device having a flanged electrophotographic photosensitive member having a flange fitted in at least one opening of a cylindrical substrate having a photosensitive layer on the surface thereof, and a developing roll having a tracking roll at least near one end thereof. In an image forming apparatus equipped with a transfer device having a transfer device and / or a transfer roll, the tracking roll is brought into contact with the outer peripheral surface of the flange of the flanged electrophotographic photosensitive member by being pressed with a predetermined pressure, A predetermined gap is formed between the developing roller and the transfer roller and / or the transfer roller.

In the present invention, since the tracking roll of the developing roll or the transfer roll is not pressed onto the photosensitive layer of the electrophotographic photosensitive member with the flange, there is no uneven wear of the photosensitive layer due to the sliding of the tracking roll, and the photosensitive layer is not exposed. Even if there is an upper-end sagging portion caused by coating at the end of the layer, or even if the photosensitive layer causes uneven wear due to slight fluctuations of the drive system, the electrophotographic photosensitive member with a cylindrical flange and the developing roll or transfer roll The gap between and can be kept constant. Therefore, the formed copy image does not have a density difference in the axial direction of the electrophotographic photosensitive member. Moreover, since the photosensitive layer does not peel off, image disturbance due to biting into other drive system, image quality defect due to peeling of the photosensitive layer itself, and malfunction of the machine due to abnormal discharge of the charger may occur. There is no.

Further, in the present invention, it is not necessary to provide an exposed portion on the cylindrical substrate of the electrophotographic photosensitive member with a flange for abutting the tracking roll, so that the photosensitive layer can be wiped off to avoid abrasion and peeling. No work required, no increase in manufacturing costs,
The electrophotographic photosensitive member can be reused without damaging the cylindrical substrate.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a schematic configuration diagram of an image forming apparatus of the present invention. Around the electrophotographic photosensitive member 1 in which flanges are fitted at both ends, a charging device 11 such as a corotron, an exposure device 12, a developing device 13 provided with a developing roll, and a transfer device 1
4, a cleaning device 15 is provided. Further, FIG. 1 is a view for explaining a mounting state of a flanged electrophotographic photosensitive member and a developing roll in the image forming apparatus of the present invention. In FIG. 1, reference numeral 1 is an electrophotographic photosensitive member, in which flanges 2 are fitted at both ends of a cylindrical substrate. Reference numeral 3 denotes a developing roll, which is provided with tracking rolls 4 in the vicinity of both ends thereof and is further provided with a pressing means 5. The tracking roll 4 of the developing roll is pressed against the outer peripheral surface of the flange 2 by the pressing means 5. As a result, a predetermined gap is formed between the photosensitive layer of the electrophotographic photosensitive member and the developing roll.

[0013]

The details of the present invention will be described below with reference to the embodiment shown in FIG. Aluminum alloy A1050 defined by JIS as a cylindrical substrate for electrophotographic photoreceptor
Prepared a blank tube. Outer diameter is 84.5 mmφ and length is 3
The inner diameter was 25 mm and the inner diameter was 82 mmφ. This raw tube was subjected to mirror-cutting processing by a precision lathe using a single crystal diamond cutting tool so that the outer diameter was 83.95 mmφ. Since the photosensitive layer is not directly involved in the present invention, detailed description thereof will be omitted.
No. 7358, that is, the surface of a cylindrical substrate is roughened by honing, and then a charge generation layer made of phthalocyanine and a charge transport layer made of a benzidine compound and a polycarbonate resin are applied by a dip coating method. Formed.

At this time, the starting point of dip coating of the photosensitive layer was a position 1 mm away from the upper end. The average thickness of the photosensitive layer was 25 μm, and the portion 20 mm from the upper end had a sag in the film thickness, so that it was a portion that could not be used for image formation. Further, in the lower end portion as well, a region of about 5 mm was disturbed in the photosensitive layer, and thus was not a portion that could be used for image formation. Therefore, the area of this photosensitive layer that can be used for image formation is 325- (20 + 5) = 300 m.
Although it was m, it was sufficient to make A3 the maximum paper size.

Flange was fitted into both openings of the cylindrical substrate of the electrophotographic photosensitive member. As the flange, a fluorine-containing polycarbonate (Upilon LS-2030, manufactured by Mitsubishi Gas Chemical Co., Inc.) was used as a material which was injection-molded into a previously prepared molding die and processed. The outer diameter of the portion of this flange that fits with the inner diameter portion of the electrophotographic photosensitive member is 82 mmφ, and the outer diameter of the portion that comes into contact with the tracking roll arranged coaxially with the developing roll described later is 84 mmφ. there were.

As a developing roll, a blank tube made of aluminum alloy A6063 defined by JIS was prepared. Outer diameter is 24.2 mmφ, length is 345 mm, inner diameter is 22 mmφ
Met. The above tube was ground by a centerless grinding machine using a grinding wheel (GC80, manufactured by Noritake Company Limited) so that the outer diameter was 24 mmφ.

The flanges fitted on both ends of the developing roll are
The aluminum alloy A5052 specified in JIS was used for the cutting work. The outer diameter of the portion fitted into the developing roll was 22 mmφ, and the outer diameter of the tracking roll to be described later was 16 mmφ. further,
An E-ring groove for fixing the tracking roll was also processed at the same time.

As the tracking roll, a polyacetal resin (Delrin, manufactured by DuPont) which was prepared by injection molding in a molding die prepared in advance was used.
The inner diameter of the part that fits the developing roll flange is 16mm
The outer diameter of the portion in contact with the electrophotographic photosensitive member with the flange was 24.1 mm and the width was 3 mm.

The above flange was fitted and fixed to the developing roll, and the tracking roll was fitted from both ends thereof and fixed by E-rings to obtain a developing roll with a flange and a tracking roll.

The developing roll having the above structure is opposed to the electrophotographic photosensitive member, and the tracking roll of the developing roll is pressed against the outer peripheral surface of the flange of the electrophotographic photosensitive member.
By pressing with a spring, an image forming apparatus having the structure shown in FIG. 2 was manufactured. The charging device, the cleaning device, and the like used were those used in a conventional manner.

[0021]

Since the image forming apparatus of the present invention has the above-mentioned structure, even if there is an upper end sagging portion caused by coating on the end portion of the photosensitive layer, the photosensitive layer is uneven due to a slight fluctuation of the drive system. Even if abrasion occurs, the gap between the electrophotographic photosensitive member with the cylindrical flange and the developing roll or the transfer roll can be kept constant. Therefore, the formed copy image does not have a density difference in the axial direction of the electrophotographic photosensitive member.

Further, since the tracking roll does not slide on the photosensitive layer, the photosensitive layer is not unevenly worn or peeled off, so that the image is disturbed by being caught in another driving system. In addition, the image quality defect due to the peeling of the photosensitive layer itself and the malfunction of the machine due to the abnormal discharge of the charger do not occur. Furthermore, since it is not necessary to provide an exposed portion when the photosensitive layer is provided on the cylindrical substrate,
Since the wiping operation is unnecessary and the cylindrical base is not scratched by the tracking roll, the electrophotographic photosensitive member can be reused.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a relationship between an electrophotographic photosensitive member and a developing device in an image forming apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of an image forming apparatus of the present invention.

FIG. 3 is a diagram illustrating a relationship between an electrophotographic photosensitive member and a developing device in a conventional image forming apparatus.

FIG. 4 is a diagram illustrating an aspect of contact between an electrophotographic photosensitive member and a developing device in a conventional image forming apparatus.

FIG. 5 is a diagram illustrating another mode of contact between the electrophotographic photosensitive member and the developing device in the conventional image forming apparatus.

[Explanation of symbols]

1 ... Electrophotographic photoreceptor, 2 ... Flange, 3 ... Development roll,
4 ... Tracking roll, 6 ... Cylindrical substrate, 7 ... Photosensitive layer, 11 ... Charging device, 12 ... Exposure device, 13 ... Developing device, 1
4 ... Transfer device, 15 ... Cleaning device.

Claims (1)

[Claims] 1. A flanged electrophotographic photosensitive member having a flange fitted in at least one opening of a cylindrical substrate having a photosensitive layer on the surface thereof, and a developing device having a developing roll provided with a tracking roll at least near one end, / Or an image forming apparatus equipped with a transfer device having a transfer roll, the tracking roll is pressed against the outer peripheral surface of the flange of the electrophotographic photosensitive member with the flange with a predetermined pressure to develop the photosensitive layer and the photosensitive layer. An image forming apparatus, wherein a predetermined gap is formed between the roll and / or the transfer roll.