JPH03203764A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To avoid cases where a photosensitive body needs to be exchanged by providing a detecting means which detects any state of deformation of a cleaning blade brought into pressurized contact with the photosensitive body surface. CONSTITUTION:When the cleaning blade 6 is brought into a pressurized contact with the surface of the photosensitive body 1 after transferring and residue toner on the photosensitive body 1 surface is eliminated by the cleaning blade 6, the state of deformation of the cleaning blade 6 brought into pressurized contact with the surface of the photosensitive body 1 is detected by a detecting means 11. Therefore, deterioration of cleaning function of the cleaning blade 6 which eliminates residual toner on the surface of the photosensitive body 1 after transferring can be easily sensed. Thus, by exchanging the cleansing blade at the time the deterioration of the cleaning function is sensed, generation of image noise due to cleaning failure and filming of the toner to the photosensitive body is controlled, and the exchanging of the photosensitive body can be avoided.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic device such as a copying machine or a printer that uses an electrophotographic process, and particularly relates to an electrophotographic device that uses an electrophotographic process to transfer toner supplied to the surface of a photoreceptor. The present invention relates to an electrophotographic apparatus in which a cleaning blade is brought into pressure contact with the surface of the photoreceptor, and toner remaining on the surface of the photoreceptor is removed by the cleaning blade.

[Prior art and its problems] Conventionally, when forming an image in an electrophotographic apparatus, the surface of a photoreceptor (1) is charged with a charger (2) as shown in FIG. Image exposure is performed on the surface of the photoreceptor (1), which has been charged to Toner is supplied from the developing device (3) to the surface of the photoreceptor (1) on which the latent image has been formed, and after forming a toner image on the surface of the photoreceptor (1), this toner image is transferred and separated into a charger. (4) onto recording paper (not shown).

After the toner image formed on the surface of the photoreceptor (1) is transferred onto the recording paper, a cleaning blade (6) made of polyurethane rubber or the like held by a blade holder (5) is moved by a spring. pressed against the surface of the photoreceptor (1) by a biasing means (7) such as;
After the transfer, the toner remaining on the surface of the photoreceptor (1) was removed by the cleaning blade (6).

However, as described above, the cleaning blade (6) is pressed against the surface of the photoreceptor (1), and the photoreceptor (1) is removed after transfer.
When the toner remaining on the surface of the cleaning blade (6) is removed, even if the toner is removed sufficiently by the cleaning blade (6) at first, the cleaning blade (6)
The cleaning blade (6) may be damaged due to deterioration of the material of the cleaning blade (6) or elongation of the biasing means (7) such as a spring that presses the cleaning blade (6) against the surface of the photoreceptor (1).
The toner is not removed sufficiently by the cleaning blade (6), and this poor cleaning by the leaning blade (6) causes problems such as noise in the formed image.

Furthermore, even if noise occurs in an image due to poor cleaning by the cleaning blade (6), it is difficult to accurately detect the presence of image noise at the beginning of the occurrence.

Therefore, even if image noise occurs due to poor cleaning as described above, image formation may be continued using the electrophotographic device described above without noticing this. If image formation is performed for a long period of time in a state of poor cleaning, toner remaining on the surface of the photoconductor (1) without being removed by the cleaning blade (6) will gradually become embedded in the surface of the photoconductor (1). As a result, so-called filming occurs, resulting in problems such as the need to replace the photoreceptor (1) itself.

[Problems to be Solved by the Invention] The present invention involves transferring the toner supplied to the surface of the photoreceptor, and then pressing a cleaning blade against the surface of the photoreceptor to remove the toner remaining on the surface of the photoreceptor. It is an object of this invention to solve the above-mentioned problems in electrophotographic apparatuses in which cleaning blades are used to remove particles.

That is, the present invention uses the cleaning blade in the above-mentioned electrophotographic apparatus to remove toner remaining on the surface of the photoreceptor after transfer. If toner is not removed sufficiently and a cleaning failure occurs, this can be detected at an early stage, causing noise in the formed image or filming on the photoconductor, requiring the photoconductor to be replaced. The goal is to eliminate situations where this would otherwise occur.

[Background of the Invention] Therefore, in order to solve the above-mentioned problems, the inventor conducted intensive research on the process by which cleaning failures occur in electrophotographic apparatuses such as those mentioned above, and found that the cleaning blade could be replaced with a spring or the like. Initially, when the force is brought into pressure contact with the surface of the rotating photoreceptor,
As shown in FIG. 7 (A>), the cleaning blade (6) is deformed into a bow shape, and the cleaning blade (6) is in contact with the surface of the photoconductor (1). (6) Edge part (6a
) and the tangential direction of the photoconductor (1) is large, and the cleaning blade (1) cleans the photoconductor (
1) Toner remaining on the surface was sufficiently removed.

However, in cases where the cleaning blade (1) has deteriorated, as shown in FIG. Due to the frictional force between the rotating photoreceptor (1), the cleaning blade (6) is gradually pulled up in the rotational direction of the photoreceptor (1), and the edge portion (6a) of the cleaning blade (6) and the photoreceptor (1) are tangentially pulled up. It has been found that as the angle θ between the photoreceptor and the photoreceptor gradually decreases, the direction of the pressing force applied by the cleaning blade (6) deviates from the center of the photoreceptor (1), and the cleaning performance of the cleaning blade (6) deteriorates.

[Means and effects for solving the problem] In order to solve the above-mentioned problem, in the present invention, after the toner supplied to the surface of the photoreceptor is transferred, a cleaning blade is applied to the surface of the photoreceptor. In an electrophotographic apparatus in which the toner remaining on the surface of the photoreceptor is removed by a cleaning blade, the cleaning blade is brought into pressure contact with the surface of the photoreceptor. I made it.

Here, in the electrophotographic apparatus as described above, when the cleaning blade is initially brought into pressure contact with the surface of the photoreceptor after transfer using a biasing means such as a spring, as shown in FIG. 7(A) above, , this cleaning blade (6) is deformed into a bow shape, and the angle θ between the edge portion (6a) of this cleaning blade (6) and the tangential direction of the photoreceptor (1) is large, and this cleaning blade ( 1) makes it possible to sufficiently remove toner remaining on the surface of the photoreceptor (1) after transfer.

However, when the electrophotographic apparatus described above is used for a long period of time, the cleaning blade (6) deteriorates and the photoreceptor (1) deteriorates as shown in FIG. 7(B). The tip of the cleaning blade (6), which was in pressure contact with the surface, is gradually pulled up in the direction of rotation of the photoconductor (1) due to the frictional force between it and the rotating photoconductor (1), and the cleaning blade (6) The angle θ between the edge portion (6a) and the tangential direction of the photoconductor (1) gradually becomes smaller, and the direction of the pressure contact force by the cleaning blade (6) shifts from the center of the photoconductor (1), causing the cleaning blade (6a) to deviate from the center of the photoconductor (1). ), the cleaning performance decreases.

In the present invention, the deformation of the cleaning blade pressed against the surface of the photoreceptor is detected by the detection means, and the deformation of the cleaning blade is thereby detected.
) The cleaning blade that removes the toner remaining on the surface of the photoconductor detects a state in which the cleaning performance deteriorates and replaces the cleaning blade, thereby preventing image noise due to poor cleaning and toner filming on the photoconductor. It is designed to suppress

[Example] Hereinafter, an example of the present invention will be specifically described based on the accompanying drawings.

(Example 1) The electrophotographic apparatus of this example also has the following features as shown in FIG.
Charge the surface of the photoreceptor (1) with a charger (2),
Image exposure is performed on the surface of the photoreceptor (1) charged in this way using an appropriate exposure means (not shown) to form an electrostatic latent image on the surface of the photoreceptor (1). Toner is supplied from the developing device (3) to the surface of the photoconductor (1) on which the electrostatic latent image is formed, and after forming a toner image on the surface of the photoconductor (1), this toner image is transferred and transferred. Separation charger (
4) onto recording paper (not shown).

After the toner image formed on the surface of the photoreceptor (1) is transferred onto the recording paper, a cleaning blade (6) made of polyurethane rubber or the like held by a blade holder (5) is moved by a spring. pressed against the surface of the photoreceptor (1) by a biasing means (7) such as;
After the transfer, the toner remaining on the surface of the photoreceptor (1) is removed by the cleaning blade (6).

Here, in this example, the cleaning blade (
As shown in FIG. 1, as a detection means (10) for detecting the deformation state of the cleaning blade (6), strain gauges (11 ). As the strain gauge (11), F-1s-12T11W3 (trade name) manufactured by Minebea ■ was used.

As shown in FIG. 2(A), before the leaning blade (6) is brought into pressure contact with the surface of the photoreceptor (1), as shown in FIG. 3(A), the above-mentioned distortion occurs. After adjusting the voltage output from the gauge (11) to Ov, move the cleaning blade (6) onto the photoreceptor (
1), and the voltage output from the strain gauge (11) was measured.

Here, as shown in FIG. 2(B), the photoreceptor (1) before the tip of the cleaning blade (6) is rotated.
When pressed against the cleaning blade (6), the cleaning blade (6)
is deformed into a bow shape, and the angle θ between the edge portion (6a) of the cleaning blade (6) and the tangential direction of the photoreceptor (1) is large, and as shown in FIG. 3(B), the above distortion occurs. The voltage output from the gauge (11) has increased.

Furthermore, when the photoconductor (1) is rotated as shown in FIG. 2(C) with the tip of the cleaning blade (6) pressed against the photoconductor (1) as described above, the photoconductor (
Cleaning blade (6) that was pressed against the surface of
) is slightly pulled up in the direction of rotation of the photoreceptor (1) due to the frictional force between it and the rotating photoreceptor (1), and the edge portion (6a) of the cleaning blade (6)
The angle θ between
) was lower than before the photoreceptor (1) was rotated.

Next, in the above-mentioned electrophotographic apparatus shown in FIG. 8, toner made of a polar styrene-acrylic resin and having an average particle size of 11 μm is supplied to the developing device (3), while
The cleaning blade (6) was made of polyurethane rubber and had a thickness of 2 mm.

Using this electrophotographic apparatus, images were formed as described above, and a 200,000-sheet printing durability test was conducted to determine the deformation state of the cleaning blade (6) and the strain gauge (11).
) to detect the point at which a cleaning failure occurs in the removal of toner remaining on the surface of the photoreceptor (1) by the cleaning blade (6).

Here, as the cleaning blade (6) deforms,
When we investigated the state in which the voltage output from the strain gauge (11) changes, we found that the number of sheets tested in the printing durability test and the strain gauge (11)
The relationship with the voltage output from 1) was as shown in FIG.

In addition, as a result of such a printing durability test, a strain gauge (1
At the time of the 200,000-sheet printing durability test when the voltage output from the cleaning blade (1) reached 1.95V, the cleaning blade (
A cleaning failure occurred in removing the toner remaining on the surface of the photoreceptor (1) using 6).

For this reason, in this embodiment, for safety reasons, the voltage output from the strain gauge (11) is higher than the above 1.95V, as shown by the broken line in FIG. 1V is the boundary line, and when the voltage output from the strain gauge (11) reaches 2.1V of this boundary line, an alarm is issued,
) to remove the toner remaining on the surface of the photoreceptor (1), it can be detected that there is a possibility that a cleaning failure may occur.

As a result, in this embodiment, by replacing the cleaning blade (6) with a new one at the time the alarm is issued, it is possible to suppress cleaning failures caused by the cleaning blade (6), and improve the quality of the formed image. It is possible to eliminate situations where noise occurs or toner is filmed on the photoreceptor (1), resulting in the need to replace the photoreceptor (1).

(Example 2) In this example, the cleaning blade (6) as shown in FIG. (6) The above blade holder (
5), the reference plate (12) is attached to a biasing means (7) such as a spring.
) is attached so as to correspond to the mounting plate (8) to which the reference plate (12) is attached, and a displacement sensor (13) is provided to measure the vertical movement of this reference plate (12).
13) to measure the distance to the reference plate (12).

That is, in this example, FIG. 7(B)
As shown in FIG.
) When the cleaning blade (6) is deformed so as to be pulled up in the rotational direction of the photoreceptor (1) due to friction with the cleaning blade (6), the cleaning blade (6)
The blade holder (5) holding the blade holder (5) is pushed by the cleaning blade (6), and the urging means (7) such as a spring is pushed by the bearing (5a) provided at the top of the blade holder (5) as a fulcrum. Since the part to which the cleaning blade (6) is attached rotates upward, the distance between the cleaning blade (6) and the reference plate (12) is measured by the displacement sensor (13), and the amount of deformation of the cleaning blade (6) is detected. It is.

In this example, the above-mentioned displacement sensor (13) is an ultrasonic type UD-1 manufactured by Keyence ■.
120 (product name), but any displacement sensor (
13) can also be used.

In this example, a 200,000-sheet printing durability test was conducted in the same manner as in Example 1, and the deformation state of the cleaning blade (6) and the displacement sensor (13) were measured. The relationship between the distance to the reference plate (12) and the distance to the reference plate (12) was investigated, and the point in time when a cleaning failure occurs in the removal of toner remaining on the surface of the photoreceptor (1) by the cleaning blade (6) was detected.

Here, as the cleaning blade (6) deforms,
Reference plate (12) measured by displacement sensor (13)
), the relationship between the number of sheets tested in the printing durability test and the distance to the reference plate (12) measured by the displacement sensor (13) is as shown in Figure 6. there were.

Further, as a result of such a printing durability test, a cleaning failure occurred in the removal of toner remaining on the surface of the photoreceptor (1) by the cleaning blade (6) at the time of the printing durability test of 200,000 sheets.

Therefore, in this embodiment, for safety reasons, the distance to the reference plate (12) measured by the displacement sensor (13) is 7.5 mm, as shown by the broken line in FIG. 15 mm as the boundary line, and when the distance to the reference plate (12) measured by the displacement sensor (13) reaches 7.15 mm, an alarm is issued, etc., and the cleaning blade (6) removes the photoreceptor (1). ) Be able to detect the possibility of a cleaning failure when removing toner remaining on the surface.

As a result, in this embodiment as well, by replacing the cleaning blade (6) with a new one when the alarm is issued, it is possible to suppress cleaning failures caused by the cleaning blade (6), and to improve the quality of the formed image. It is possible to eliminate situations where noise occurs or toner is filmed on the photoreceptor (1), resulting in the need to replace the photoreceptor (1).

[Effects of the Invention] As detailed above, in the electrophotographic apparatus according to the present invention, the cleaning blade is brought into pressure contact with the surface of the photoreceptor after transfer, and the toner remaining on the surface of the photoreceptor is removed by the cleaning blade. In this process, a detection means detects the deformation of the cleaning blade that is pressed against the surface of the photoreceptor, and this determines the cleaning performance of the cleaning blade that removes toner remaining on the surface of the photoreceptor after transfer. Decrease can now be easily detected.

As a result, in the electrophotographic apparatus according to the present invention, when the detection means detects a decrease in the cleaning performance of the cleaning blade, the cleaning blade can be replaced, thereby preventing image noise caused by poor cleaning or the photoreceptor. It is also possible to suppress toner filming on the photoreceptor, thereby avoiding the need to replace the photoreceptor.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a state in which a strain gauge is attached to a cleaning blade in Embodiment 1 of the present invention;
Figures (A), (B), and (C) show the state before C when the cleaning blade is pressed against the photoreceptor, the state when the cleaning blade is pressed against the photoreceptor, and the state when the cleaning blade is pressed against the photoreceptor in the same embodiment. FIG. 3(A) is a partial side view showing a rotated state of the photoreceptor. (B) and (C) are the above-mentioned FIGS. 2 (A) and (B). FIG. 4 is a diagram showing the state of the voltage output from the strain gauge in the state of (C); FIG. Fig. 5 is a perspective view showing the state in which the deformed state of the cleaning blade is detected by the displacement sensor in Embodiment 2 of the present invention, and Fig. 6 shows the number of sheets tested in the printing durability test and the reference plate measured by the displacement sensor in the same embodiment. 7(A) and 7(B) are partial side views showing the deformed state of the cleaning blade pressed against the surface of a rotating photoreceptor, and FIG. 8 is an electrophotographic apparatus. FIG. (1)...Photoreceptor, (6)...Cleaning blade. <10)...Detection means. Number of sheets tested (X 10') Number of sheets tested (X 10')

Claims (1)

[Claims] 1. After transferring the supplied toner to the surface of the photoreceptor,
In an electrophotographic apparatus in which a cleaning blade is brought into pressure contact with the surface of the photoreceptor and the cleaning blade removes toner remaining on the surface of the photoreceptor, deformation of the cleaning blade that is brought into pressure contact with the surface of the photoreceptor. An electrophotographic device characterized by being provided with a detection means for detecting a state.