JP2001034139A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively secure heaped toner brought into contact with the surface of an image carrier, to trap paper powder and to reduce the friction of a contact part between the image carrier and a cleaning means. SOLUTION: This image forming device is constituted as follows. A prescribed printing pattern consisting of the composite pattern of solid and white or a half pattern is selected from the plural printing patterns 1, 2,...(n) (S1). Then, an electrostatic latent image is formed with the selected printing pattern (S2) and developed with toner (S3). Besides, the toner is heaped by adjusting the quantity of toner arriving at a cleaning blade part (S4).

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 which reduces friction at a contact portion between a cleaning member for scraping off residual toner on the surface of an image carrier and the image carrier.

[0002]

2. Description of the Related Art A rake sheet in the form of a film, which is gently pressed against the surface of an image carrier, is disposed below a cleaning blade for removing toner by contact of the edge with the surface of the image carrier, and a retaining wall opposed thereto. Then, the toner removed by the cleaning blade is deposited in a space between the rake sheet and the retaining wall, and the deposited toner is softly brought into contact with the surface of the image carrier to trap paper powder slipping through the rake sheet. It has been proposed (Japanese Unexamined Patent Publication No. 1-1612
No. 88).

Further, toner scraped off by a cleaning blade is deposited on a rake sheet and a rotatable deposition plate, and the deposited toner is softly brought into contact with the surface of an image carrier to remove paper dust passing through the rake sheet. There is also proposed a device in which the accumulated toner is dropped to the lower part of the casing by trapping the toner and rotating the stacking plate (Japanese Patent Application Laid-Open No. 5-127577).

[0004]

However, the above-mentioned conventional apparatus does not disclose how and when toner is stored in the vicinity of a rake sheet, and accumulation of toner is not possible depending on how the image forming apparatus is used. Therefore, the paper dust cannot be trapped effectively, and the paper dust may directly hit the cleaning blade to cause a streak-like stain on an image.

[0005] The present invention is to solve the above problems,
Effectively secure the deposited toner that comes into contact with the image carrier surface,
It is an object of the present invention to trap paper dust and reduce friction at a contact portion between an image carrier and a cleaning unit.

[0006]

According to the present invention, there is provided an image forming apparatus comprising: charging means for charging the surface of an image carrier; and electrostatic latent image forming means for forming an electrostatic latent image on the surface of the image carrier. Developing means for developing the electrostatic latent image with toner, transferring means for transferring the developed toner image, a cleaning blade for scraping off the toner remaining on the surface of the image carrier, and a part of the toner scraped by the cleaning blade And a cleaning unit including a deposition member that deposits the toner on the surface of the image carrier so as to rub the image on the surface of the image carrier, comprising: a selection unit that selects a predetermined print pattern from a plurality of print patterns. An electrostatic latent image is formed with the selected print pattern, toner is developed, and the toner on the surface of the image carrier is scraped off by the cleaning blade and deposited on the deposition member. Characterized in that was. The invention according to claim 2 is characterized in that the print pattern is a composite pattern of solid and white. The invention according to claim 3 is characterized in that the print pattern is a half pattern. Further, the invention according to claim 4, further comprising a transfer bias control means for controlling a transfer bias of the transfer means, wherein the transfer bias is controlled by the transfer bias control means, and the cleaning blade removes toner remaining on the surface of the image carrier after transfer. And is deposited on the deposition member.

[0007]

Embodiments of the present invention will be described below.

In the field of image forming apparatuses such as copiers and printers using an electrophotographic process, there is a tendency for higher image quality (smaller toner particle size), higher speed, and longer life, and particularly, a smaller toner particle size. In order to prevent a decrease in the fluidity of the toner, an excessive amount of a fluidity improver (inorganic substance) such as silica or titanium oxide is added, and therefore, the cleaning property of the toner tends to deteriorate. I have. To improve (ensure) the cleaning performance, it is necessary to increase the contact pressure and the contact angle of the cleaning blade. However, if the cleaning performance is improved in this way, the frictional force between the blade and the surface of the image carrier is increased. And the cleaning blade is turned up. In particular, turning over is likely to occur in an image pattern with little residual toner or in a high temperature and high humidity environment.

In order to solve this problem, the present applicant has proposed to stabilize the frictional force between the blade and the surface of the image carrier at a low level by accumulating toner in a contact portion between the cleaning blade and the image carrier. As a result, the contact pressure and contact angle of the cleaning blade are made tighter, and the problem of turning over can be solved while ensuring the cleaning property, and the performance of the cleaner can be greatly improved. Therefore, in the present invention, the method of storing the toner is devised irrespective of the countermeasures against foreign matter such as paper dust and the countermeasures against turning up the cleaning blade.

FIG. 1 is a schematic view showing the overall configuration of an image forming apparatus according to the present invention, and FIG. 2 is a view illustrating a cleaning apparatus according to the present invention. The drum-shaped photoconductor 1 is driven to rotate in the direction of arrow D by a driving source (not shown). A charging roller 2 is arranged on the outer periphery of the photoconductor 1, and uniformly charges the surface of the photoconductor 1 while rotating in contact with the photoconductor 1. The uniformly charged photoconductor 1 is selectively scanned and exposed as a first color according to, for example, yellow image information by a latent image forming unit (not shown), and a yellow electrostatic latent image is formed. On the downstream side in the rotation direction of the photoreceptor 1 on which the electrostatic latent image is recorded, developing means 4, 5, 6, and 7 which store yellow, magenta, cyan, and black toners as developers, respectively, are arranged and formed. The yellow electrostatic latent image thus developed is developed by contacting only the yellow developing unit 4 with the photoconductor 1 to form a yellow toner image.

An intermediate transfer belt 8 is disposed adjacent to the photoconductor 1 on the downstream side in the rotation direction of the photoconductor 1 on which the toner image is formed. The intermediate transfer belt 8 is wound around a driving roller 9, a backup roller 10, a tension roller 11, and a wrinkle removing roller 12, and is driven at the same speed as the peripheral speed of the photoconductor 1. In addition, by transmitting the driving force of the photoconductor 1 to the driving roller 9, the photoconductor 1 and the intermediate transfer belt 8 are driven synchronously. The primary transfer roller 13 is urged toward the photoreceptor 1 via the intermediate transfer belt 8. At a primary transfer position where the intermediate transfer belt 8 is sandwiched between the photoreceptor 1 and the primary transfer roller 13, a high-voltage power supply (not shown) is used. When a voltage is supplied to the primary transfer roller 13, the yellow toner image is transferred to the surface of the intermediate transfer belt 8. The photoreceptor 1 having transferred the yellow toner image to the intermediate transfer belt 8 further rotates in the direction of arrow D, and the toner remaining on the surface is scraped off by the cleaning blade 16, so that the image can be formed again. It is to be noted that the charge removing means for resetting the photoconductor potential before charging may be operated. By repeating the same procedure for the second to fourth color images in this manner, four color toner images are sequentially superimposed and recorded on the intermediate transfer belt 8.

The cleaning blade 16 is attached to the inside of the case 14 by a cleaning blade supporting metal plate 15, and the tip of the cleaning blade 16 is in contact with the surface of the photosensitive member 1. A rake sheet 17 is attached to the lower side of the case 14 so as to face the cleaning blade 16 so that the residual toner scraped off by the cleaning blade 16 does not leak out of the case. In addition to the rake sheet, a toner accumulating member 18 is provided so as to extend to a position higher than the leading edge of the cleaning blade 15, accumulates scraped toner, and accumulates the accumulated toner on the surface of the photoconductor 1 and the cleaning blade. So that it also accumulates in the contact area.

That is, as shown in FIG. 2, the toner 20 accumulates in the space formed by the rake sheet 17, the toner accumulating member 18, and the surface of the photosensitive member 1, and the tip of the cleaning blade 16 is buried in the toner. As a result, the toner is present at the contact portion between the surface of the photoconductor 1 and the cleaning blade, so that the frictional force between the two can be stabilized at a low level. In addition, a cloud is usually generated from the tip of the cleaning blade. However, since the cloud is buried in the toner, the generation of the cloud is prevented, and contamination outside the apparatus can be prevented.

Next, a method for storing toner in the toner accumulation member will be described. To efficiently supply toner to the cleaning blade, for example, an electrostatic latent image is formed in a black pattern, the photoreceptor is solid-developed, and most of the developed toner is removed from the cleaning blade without applying a transfer bias. It is to reach. However, if an excessively large amount of toner is supplied to the cleaner by such a method, a cleaning failure occurs, most of the toner passes through the cleaning blade, and there is a possibility that the toner cannot be accumulated in the toner accumulation member.

Therefore, in the present invention, an appropriate amount of toner is supplied to the cleaner by using a composite pattern including a solid portion 30 and a white portion 31, as shown in FIG. According to such a pattern, the toner supply amount to the cleaning blade can be freely adjusted by changing the area ratio of the solid portion 30 and the white portion 31.

Further, as shown in FIG. 4, a half pattern 40 composed of a halftone dot pattern may be used to supply an appropriate amount of toner to the cleaner. Again,
By changing the area ratio of the halftone black dots, the amount of toner supply to the cleaning blade can be freely adjusted.

FIG. 5 is a diagram showing a flow in the case where the amount of toner is adjusted by the composite pattern to store the toner. A plurality of print patterns 1, 2... N having different black solid portions and white portions are prepared, and a specific print pattern is selected from these (S 1). Next, an electrostatic latent image is formed based on the selected print pattern (S2), the toner is developed (S3), and the toner is supplied to a cleaning blade to scrape off the toner, and a toner accumulation process for accumulating with a toner accumulation member is performed. Perform (S4). By selecting the print pattern in this manner, the amount of toner reaching the cleaning blade can be adjusted, so that toner accumulation can be performed without causing cleaning failure. By not applying the transfer bias, most of the developed toner reaches the cleaning blade portion, and the toner can be supplied efficiently.

FIG. 6 is a diagram showing a flow in the case where the toner is adjusted by the transfer bias control to store the toner.
First, a predetermined print pattern is selected to form an electrostatic latent image (S11 to S12). The printing pattern at this time is arbitrary, and may be a pattern as shown in FIGS. 3 and 4 or a solid pattern. Next, the toner is developed (S1
3) Then, transfer is performed (S14), and then, a toner storing process is performed (S15). In the embodiment of the present invention, the intermediate transfer belt is used. However, the image may be transferred to a sheet. In this transfer, the transfer bias is controlled to adjust the amount of toner to be transferred. By controlling the transfer bias, the amount of toner reaching the cleaning blade portion is adjusted, and the toner can be stored without causing cleaning failure.

[0019]

As described above, according to the present invention, a predetermined printing pattern, for example, a printing pattern such as a composite pattern of solid and white or a half pattern is selected from a plurality of printing patterns and an electrostatic latent image is formed. An image is formed, the toner is developed, and the amount of the toner reaching the cleaning blade portion is adjusted, so that the toner can be stored without causing a cleaning failure.

Further, the amount of toner that reaches the cleaning blade by controlling the transfer bias can be adjusted, and the toner can be stored without causing cleaning failure.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an overall configuration of an image forming apparatus of the present invention.

FIG. 2 is a diagram illustrating a cleaning device of the present invention.

FIG. 3 is a diagram showing a solid and white composite pattern.

FIG. 4 is a diagram showing a half pattern.

FIG. 5 is a diagram showing a flow in a case where toner is stored by adjusting a toner amount by a composite pattern.

FIG. 6 is a diagram showing a flow in a case where toner is adjusted by transfer bias control to store toner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoreceptor, 2 ... Charging roller, 4, 5, 6, 7 ... Developing means, 8 ... Intermediate transfer belt, 9 ... Driving roller, 10 ... Backup roller, 11 ... Tension roller, 12 ... Wrinkle removing roller, 13 ... Primary transfer roller, 14 ... case, 15
... cleaning blade support sheet metal, 16 ... cleaning blade, 17 ... rake sheet, 18 ... toner accumulation member, 19 ... holding member, 20 ... accumulated toner, 30 ... solid portion, 31 ... white portion.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahiro Maeda 3-3-5 Yamato, Suwa-shi, Nagano F-term in Seiko Epson Corporation (reference) 2H027 DA32 EA09 EC03 ED24 ED28 EF09 HB19 2H032 AA05 BA01 BA05 BA09 CA02 CA13 2H034 AA02 AA05 AA06 AA07 BA05 BF01 CA04

Claims (4)

[Claims] A charging means for charging a surface of the image carrier;
Electrostatic latent image forming means for forming an electrostatic latent image on the surface of the image carrier, developing means for developing the formed electrostatic latent image with toner,
A transfer means for transferring the developed toner image, a cleaning blade for scraping off the toner remaining on the surface of the image carrier, and a portion of the toner scraped off by the cleaning blade for depositing so as to rub against the surface of the image carrier. An image forming apparatus comprising: a cleaning unit including a deposition member; and a selection unit that selects a predetermined print pattern from a plurality of print patterns, and forms an electrostatic latent image with the print pattern selected by the selection unit. An image forming apparatus, wherein the toner is developed, and the toner on the surface of the image carrier is scraped off by the cleaning blade and deposited on a deposition member. 2. The image forming apparatus according to claim 1, wherein the print pattern is a composite pattern of solid and white. 3. The image forming apparatus according to claim 1, wherein the print pattern is a half pattern. 4. A charging means for charging a surface of an image carrier,
Electrostatic latent image forming means for forming an electrostatic latent image on the surface of the image carrier, developing means for developing the formed electrostatic latent image with toner,
A transfer means for transferring the developed toner image, a cleaning blade for scraping off the toner remaining on the surface of the image carrier, and a portion of the toner scraped off by the cleaning blade for depositing so as to rub against the surface of the image carrier. An image forming apparatus comprising: a cleaning unit including a deposition member; and a transfer bias control unit configured to control a transfer bias of the transfer unit. The transfer bias is controlled by the transfer bias control unit. An image forming apparatus, wherein the removed toner is scraped off by the cleaning blade and deposited on a deposition member.