JP2001142368A - Cleaning method for organic photoreceptor drum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method for an organic photoreceptor drum by which toner is effectively prevented from infiltrating to the surface of the photoreceptor drum on which a positioning roller abuts. SOLUTION: Non-coated surfaces A and B where an organic photoreceptive layer is not formed exist at both end parts of the pipe stock of the organic photoreceptor drum 1, and the positioning rollers 7 of a developing roller 5 abut on the surfaces A and B, so that a distance between the roller 5 and an organic photoreceptive layer 3 is kept to be constant. Then, a cleaning blade 8 is inclined to the axial direction of the drum 1 so that the end 8b on either side of the blade 8 may be inside from the end of the coating finishing side of the layer 3, the end 8a on the other side of the blade 8 may be outside from a positioning roller abutting surface, and the end 8a may be positioned on a more downstream side in the rotating direction of the drum 1 than the end 8b, and is made to abut on the annular surface of the drum 1 so as to clean the drum 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer,
The present invention relates to a method for cleaning an organic photosensitive drum used in an electrophotographic apparatus such as a facsimile.

[0002]

2. Description of the Related Art In an electrophotographic apparatus represented by a copying machine, the surface of a photosensitive drum is uniformly charged, and an electrostatic latent image corresponding to a document image is formed on the surface of the photosensitive drum by image exposure. By developing the electrostatic latent image to form a toner image on the surface of the photoconductor drum, transferring the toner image from the surface of the photoconductor drum onto transfer paper, and fixing the transferred toner image by heat, pressure, or the like. , An image is formed.

In such an electrophotographic apparatus, an electrostatic image formed on the surface of a photosensitive drum is developed by using a magnetic developer or a liquid developer containing a toner charged to a predetermined polarity.
This is performed by supplying the developer onto the surface of the photosensitive drum by a developer conveying roller. After the toner image formed on the surface of the photoconductor is transferred by developing the electrostatic latent image, the toner remaining on the surface of the photoconductor is removed by a cleaning blade, and the surface of the photoconductor drum is further neutralized. Thus, one cycle of image formation is completed, and the next image formation is performed.

In the above-described electrophotographic apparatus, the distance between the surface of the photosensitive drum and a developer conveying roller (hereinafter, sometimes referred to as a developing roller) is set to a constant value with high accuracy. It is necessary. That is, when the distance fluctuates, the electric force for transferring the charged toner on the developing roller to the photosensitive drum fluctuates or is supplied to the developing area (the gap between the photosensitive drum and the developer roller). This is because the amount of the charged toner fluctuates, which causes variations in the density of the formed image, toner scattering, fog, and the like.

For this reason, in a conventionally known electrophotographic apparatus, positioning rollers are provided at both ends of a rotating shaft of a developing roller.
In order for this positioning roller to contact the photoreceptor drum surface,
A photosensitive drum and a developing roller are arranged. That is, the distance between the surface of the photosensitive drum and the surface of the developing roller is always kept constant by bringing the positioning roller into contact with the surface of the photosensitive drum.

On the other hand, as the photosensitive drum, an inorganic photosensitive drum having an inorganic photosensitive layer such as an amorphous silicon photosensitive layer or a selenium photosensitive layer, or a charge generating agent or a charge transporting agent dispersed in a binder resin is used. Organic photosensitive drums having such organic photosensitive layers are widely used. Among such photosensitive drums, the organic photosensitive drum has a disadvantage that the organic photosensitive layer is easily scraped. That is, if the interval is set by contacting the above-described positioning roller with the organic photosensitive layer, the organic photosensitive layer is scraped as the image formation is repeated,
There is a problem that the distance between the organic photosensitive layer and the developing roller set by the positioning roller fluctuates. For this reason, an organic photosensitive layer is formed by applying a coating liquid in which an organic photosensitive material is dispersed or dissolved to the central portion of the annular surface of a conductive element tube such as aluminum to form an organic photosensitive layer. The above-mentioned positioning roller is brought into contact with the (surface on which the organic photosensitive layer is not formed).

Further, when cleaning (removal of toner remaining on the photosensitive layer after transfer) is performed by bringing a cleaning blade into contact with the organic photosensitive drum, the cleaning blade is in contact with an end of the organic photosensitive layer. In addition, there is a problem that the organic photosensitive layer is peeled off from the end. For this reason, in the organic photosensitive drum in which the uncoated surfaces are formed at both ends of the annular surface of the conductive element tube as described above, the organic photosensitive drum is so arranged that the cleaning blade does not contact the end of the organic photosensitive layer. Cleaning is performed by bringing the cleaning blade into contact only within the layer.

[0008]

However, when the cleaning is performed as described above, since the cleaning blade is not in contact with the non-coating surface with which the positioning rollers are in contact, the toner is in contact with the positioning rollers. Penetrates, and the set interval between the photosensitive drum and the developing roller fluctuates due to the positioning rollers. That is, since the developer is not supplied to the non-coated surface,
Basically, no toner is present on the non-coated surface, but the toner blocked by the cleaning blade moves to both ends of the blade by the rotation of the photosensitive drum, and further, the non-coated surface. Flowed to
It enters between the positioning roller and the conductive element tube as the photosensitive layer supporting substrate. In particular, when an image is formed using a liquid developer in which a charged toner is dispersed in a liquid having a high insulating property and a low dielectric constant, the above tendency is extremely high because the fluidity of the toner is high.

Accordingly, it is an object of the present invention to effectively prevent the toner from entering the positioning roller contact surface, and to clean the organic photosensitive drum without changing the distance between the organic photosensitive layer and the developing roller. It is to provide a method.

[0010]

According to the present invention, an organic photosensitive drum is arranged to face a developing roller for transporting a developer, and the organic photosensitive layer of the drum is rotated while rotating the organic photosensitive drum. A cleaning blade for contacting the surface of the organic photosensitive layer to clean toner adhered to the surface of the organic photosensitive layer, wherein the organic photosensitive layer of the organic photosensitive drum is disposed at the center of the annular surface of the conductive element tube. An uncoated surface on which an organic photosensitive layer is not formed is formed at both ends of the conductive element tube by applying a coating solution containing an organic photosensitive agent, and the developing roller rotates Positioning rollers are provided at each of the shaft end portions, and the positioning rollers are in contact with the non-coating surfaces of both end portions of the annular surface of the organic photosensitive drum,
The interval between the developing roller and the organic photosensitive layer is fixedly defined, and one end of the cleaning blade is located inside the coating end side end of the organic photosensitive layer, and At the other end of the cleaning blade,
Beyond the coating end side end of the organic photosensitive layer, and positioned outside the positioning roller contact surface on the non-coated surface,
The cleaning blade is inclined with respect to the axial direction of the organic photoconductor drum so that an end of the cleaning blade located on the non-coating surface is located downstream of the other end in the rotation direction of the organic photoconductor drum. Then, the cleaning blade is brought into contact with the annular surface of the organic photosensitive drum to perform the cleaning, thereby providing a method of cleaning the organic photosensitive drum.

In summary, the most important features of the present invention are:
(1) One end of the cleaning blade is disposed in the organic photosensitive layer, and the other end is extended to a non-coating surface (a region where the organic photosensitive layer is not formed), and the cleaning is performed even on the positioning roller contact surface. (2) so that the end on the non-coating surface side of the cleaning blade is located downstream of the other end located in the organic photosensitive layer in the rotation direction of the photosensitive drum, The point is that the blade is inclined and brought into contact with the surface of the photosensitive drum.

The feature (1) will be described. In the case where an organic photosensitive layer is formed by applying a coating liquid to the annular surface of a conductive tube made of aluminum or the like, the end portion on the application start side smoothly increases in thickness. However, the end portion on the side of the coating end portion is a convex portion which rises upward due to the end surface treatment with the solvent. For this reason, when the cleaning blade is brought into contact with the edge of the organic photosensitive layer, the photosensitive layer hardly peels at the coating start end, and the photosensitive layer peels intensively at the coating end side. . Therefore,
In the present invention, the cleaning blade is not brought into contact with the end of the organic photosensitive layer on the coating end side, the end of the blade is positioned in the organic photosensitive layer, and the end of the organic photosensitive layer on the other side of the coating start side is positioned on the coating start side. Is to contact the blade and extend it to the non-coated surface area to clean the contact surface of the positioning roller.

Further, the feature (2) will be described.
When the blade is arranged as described above, cleaning is effectively performed on the non-coating surface adjacent to the end of the organic photosensitive layer on the coating start side, and the intrusion of the toner into the positioning roller contact surface located in this portion is prevented. Effectively prevented. Therefore, there is a problem that the toner enters the non-coating surface adjacent to the end of the organic photosensitive layer on the coating end side. Therefore, in the present invention, the cleaning blade is inclined with respect to the axial direction of the photosensitive drum, and the end of the cleaning blade extending to the coating surface adjacent to the end of the organic photosensitive layer on the coating start side is connected to the other end. Of the photosensitive drum relative to the rotation direction of the photosensitive drum. By inclining the cleaning blade in this manner, the toner blocked by the blade moves to the application start side of the organic photosensitive layer. Therefore, the intrusion of the toner onto the non-coating surface adjacent to the end of the organic photosensitive layer on the coating end side is effectively prevented. On the other hand, even if the toner flows into the other side, the non-coated surface on this side is cleaned by extending the cleaning blade, so that the toner does not enter the positioning roller contact surface. .

As described above, according to the present invention, the peeling of the edge of the organic photosensitive layer is effectively avoided, and at the same time, the intrusion of the toner into the contact surface of the positioning roller is effectively prevented. It does not fluctuate due to intrusion.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to specific examples shown in the accompanying drawings. FIG. 1 is a plan view showing a positional relationship among a photosensitive drum, a developing roller, and a cleaning blade for performing the cleaning method of the present invention. FIG. 2 is a cross-sectional view of the organic photosensitive layer of the organic photosensitive drum shown in FIG. FIG.

In FIG. 1, an organic photosensitive drum (hereinafter, simply referred to as a photosensitive drum) indicated by 1 is formed by applying a coating liquid containing an organic photosensitive material onto a conductive element tube 2 made of aluminum or the like. As is clear from FIG. 1, the non-coated surfaces A and B are formed at both ends of the conductive element tube 2, respectively. No organic photosensitive layer 3 is formed. A developing roller 5 is arranged so as to face the photosensitive drum 1, and the entire developing roller 5 faces the organic photosensitive layer 3. That is, the width of the organic photosensitive layer 3 is larger than the width of the developing roller, so that the developer conveyed by the developing roller 5 is always supplied onto the organic photosensitive layer 3. Positioning rollers 7 are provided at both ends of the rotating shaft 6 of the developing roller 5, and the positioning rollers 7 contact the non-coating surfaces A and B at both ends of the photosensitive drum 1. 5 and the organic photosensitive layer 3 of the photosensitive drum 1 are always kept constant. In FIG. 1, the contact surface of the positioning roller 7 is indicated by 50.
Further, a cleaning blade 8 is in contact with the photosensitive drum 1.

In the electrophotographic apparatus in which the photosensitive drum 1, the developing roller 5, and the cleaning blade 8 are disposed as described above, the entire surface of the organic photosensitive layer 3 is uniformly and uniformly fixed to a predetermined polarity while rotating the photosensitive drum 1. Then, an image is exposed to light to attenuate the potential of the light-irradiated portion to form an electrostatic image. Further, the developing roller 5 allows a one-component or two-component magnetic developer or a liquid developer obtained by dispersing a charged toner in a solvent, which is known per se, to a developing area between the organic photosensitive layer 3 and the developing roller 5. And the developer is used to develop the electrostatic image to form a toner image on the organic photosensitive layer 3. This toner image is
An image is formed by being transferred onto a predetermined transfer material (for example, paper) surface by a transfer device such as a transfer charger or a transfer roller, and fixing the toner image on the transfer material surface by heat, pressure, or the like. The organic photosensitive layer 3 after the transfer of the toner image is rubbed by the cleaning blade 8 described above,
The toner remaining on the surface of the photosensitive layer 3 is scraped off, and the charged charge on the photosensitive layer 3 is removed by light irradiation with a static elimination lamp or the like, whereby the image forming cycle is completed and the next image formation is performed.

In the above-described photosensitive drum 1, the organic photosensitive layer 3 is composed of a layer in which a charge generating agent and a charge transporting agent are dispersed in a binder resin, and the organic photosensitive layer 3 may be a single layer. For example, it may have a laminated structure in which a charge generating layer containing a charge generating agent and a charge transporting layer containing a charge transporting agent are laminated. Such an organic photosensitive layer 3 is formed by applying a coating liquid containing these photosensitive layer forming materials to the annular surface of the conductive element tube 2,
One end 3a is an application start side end,
The other end 3b is a coating end side end. Accordingly, the non-coated surface A where the organic photosensitive layer 3 is not formed is adjacent to the coating start side end 3a of the organic photosensitive layer 3, and the non-coated surface B is the coating end side end of the organic photosensitive layer 3. 3b.

In FIG. 2 showing the cross section of the organic photosensitive layer 3 described above, the coating start side end 3a is formed so as to increase its thickness very smoothly.
In b, since the end face treatment using a solvent is performed to adjust the width and the position of the organic photosensitive layer 3, a raised portion 60 is formed. Therefore, as can be understood from FIG. 2, when the cleaning blade 8 is brought into contact with the coating start side end 3a, the photosensitive layer 3 hardly peels from this portion, but the coating end side end 3a. When the cleaning blade 8 is brought into contact with the 3b cleaning blade 8, the photosensitive layer 3 is separated from this portion because the raised portion 60 is formed.

Returning to FIG. 1 again, as is apparent from the above, in the present invention, the end 8a of the cleaning blade 8 located on the photosensitive layer application start side is extended to the non-coating surface A, The cleaning of the positioning roller contact surface 50 existing in the coating surface A is performed. That is,
The coating start side end 3a of the organic photosensitive layer 3 contacts the cleaning blade 8, but as described above, the organic photosensitive layer 3 does not peel off from the coating start side end 3a. on the other hand,
The end 8b of the cleaning blade 8 located on the photosensitive layer application end side does not extend to the non-coating surface B, but is located inside the application end side end 3b of the organic photosensitive layer 3. Therefore, the coating end side end 3b of the organic photosensitive layer 3 is not in contact with the cleaning blade 8, and the organic photosensitive layer 3 does not peel off from this portion. It is needless to say that the end 8b of the cleaning blade 8 located on the side where the application of the photosensitive layer is completed needs to be located outside the side surface 5a of the developing roller 5. If it is located inside the side surface 5a of the developing roller 5, cleaning failure occurs in an area where development is performed by the developing roller 5.

Further, in the present invention, the cleaning blade 8 is disposed so as to be inclined with respect to the axial direction of the photosensitive drum 1. That is, as is clear from FIG. 1, the end 8a of the cleaning blade 8 located on the photosensitive layer application start side.
Is positioned downstream of the other end 8b in the rotation direction of the photosensitive drum 1 (indicated by an arrow C in FIG. 1).

When the cleaning blade 8 is inclined in this manner, the toner blocked by the blade 8 moves from the end 8b to the downstream end 8a by the rotational force of the photosensitive drum 1. . Therefore, the cleaning by the cleaning blade 8 is not performed on the non-coated surface B, but there is no possibility that the toner will flow out into this area, and the intrusion of the toner into the positioning roller contact surface 50 located in the non-coated surface B will not occur. Effectively prevented. On the other hand, although the toner flows to the end 8a side of the cleaning blade 8 located on the photosensitive layer application start side, the cleaning blade 8
Are extended, and cleaning is performed by the blade. Therefore, the toner does not enter the positioning roller contact surface 50 located in the non-coated surface A.

In the above-described present invention, the inclination angle θ of the cleaning blade 8 with respect to the axial direction of the photosensitive drum 1 is set.
Although it varies depending on the diameter of the photosensitive drum 1 (conductive tube 2) and the width of the organic photosensitive layer 3 or the developing roller 5, it is generally preferable to set the angle in the range of 1 to 2 °. If the inclination angle θ is larger than necessary, the cleaning area becomes excessively large, and it becomes difficult to make the ground space of other mechanisms disposed around the photosensitive drum 1 sufficiently large. If the inclination angle θ is too small,
This is because it is difficult to prevent the toner from entering the non-coated surface B.

The above-described cleaning method of the present invention is particularly useful for an electrophotographic apparatus in which development is performed using a liquid developer in which a charged toner is dispersed in a solvent. That is, when the liquid developer is used, the fluidity of the toner is extremely high, and the intrusion of the toner into the positioning roller contact surface 50 due to the flow of the toner is extremely likely to occur. According to the present invention, even when a liquid developer is used, such intrusion of the toner can be effectively prevented.

[0025]

According to the present invention, it is possible to effectively prevent toner from entering the surface contacting the positioning roller without causing the organic photosensitive layer to be scraped or peeled off, and to provide a photosensitive drum defined by the positioning roller. The distance between the developing roller and the developing roller is always kept constant, and image defects due to the fluctuation of the distance can be effectively avoided.

[Brief description of the drawings]

FIG. 1 is a plan view showing a positional relationship among an organic photosensitive drum, a developing roller, and a cleaning blade for performing a cleaning method of the present invention.

FIG. 2 is a diagram showing a cross section of an organic photosensitive layer of the organic photosensitive drum of FIG.

[Explanation of symbols]

 1: photosensitive drum 2: conductive tube 3: organic photosensitive layer 5: developing roller 7: positioning roller 8: cleaning blade 50: positioning roller contact surface

Claims (2)

[Claims] An organic photosensitive drum is disposed so as to face a developing roller for transporting a developer, and a cleaning blade is brought into contact with an organic photosensitive layer of the drum while rotating the organic photosensitive drum. In the method for cleaning an organic photosensitive drum for cleaning toner adhered to a layer surface, the organic photosensitive layer of the organic photosensitive drum is coated with a coating liquid containing an organic photosensitive agent on a central portion of an annular surface of a conductive tube. Non-coated surface on which the organic photosensitive layer is not formed is formed at both end portions of the conductive element tube, and the developing roller is provided at each of both end portions of the rotation shaft thereof.
Positioning rollers are provided, and the positioning rollers are in contact with the non-coating surfaces at both ends of the annular surface of the organic photoconductor drum, so that the distance between the developing roller and the organic photosensitive layer is fixed. At the same time, one end of the cleaning blade is positioned inside the coating end side of the organic photosensitive layer, and the other end of the cleaning blade is coated with the organic photosensitive layer. Beyond the side end, and positioned outside the positioning roller contact surface on the non-coating surface, the end of the cleaning blade located on the non-coating surface is more organic photosensitive than the other end. Cleaning is performed by inclining the cleaning blade with respect to the axial direction of the organic photosensitive drum so that the cleaning blade is in contact with the annular surface of the organic photosensitive drum so as to be positioned on the downstream side in the rotation direction of the body drum. The cleaning method of an organic photosensitive drum, wherein. 2. The cleaning method according to claim 1, wherein an inclination angle θ of the cleaning blade with respect to the axial direction of the organic photoconductor drum is set to 1 to 2 ° to make contact with the annular surface of the organic photoconductor drum.