JP2003076235A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus whose components can be replaced inexpensively and whose maintenance can be carried out while saving labor and time by preventing toner from leaking to the outside of a photoreceptor cleaning means. SOLUTION: Foamed polyurethane-made side seals 6a/6b are arranged on both ends of a cleaning blade (consisting of a rubber blade 3 and an alloyed holder 2) in the longitudinal direction. A skin layer is formed on the surface of a photoreceptor to be abutted on the cleaning blade so that the seals 6a/6b can be abutted on the abutting edge of the cleaning blade on the photoreceptor. The pore of the foamed polyurethane is made independent or semi-independent from another pore and made to have <=150 μm diameter. The restriction of the seals 6a/6b is strengthened by making larger the external forms of non- contact parts of the seals 6a/6b with the edge of the cleaning blade and widening the area where a double coated adhesive tape is adhered.

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 such as a copying machine, a facsimile or a printer, and more particularly, it is a one-component developing type or two-component developing type image forming apparatus having a drum-shaped photosensitive member. The present invention relates to an image forming apparatus having a mechanism that collects the transfer residual toner on a cleaning device by a fixed cleaning blade.

[0002]

2. Description of the Related Art In recent digital image forming apparatuses,
In most cases, the cleaning means for the photosensitive member is arranged above the photosensitive member in view of the arrangement of the device due to miniaturization and the like.
Further, the cleaning means includes a brush type and a blade type, but the blade type is generally used because of its simple structure and low cost. With the blade method,
The tip edge (blade edge) of the cleaning blade is pressed against the photoconductor to scrape the transfer residual toner adhering to the photoconductor. Here, in the case of an image forming apparatus in which the cleaning blade is arranged beside the photoconductor, the transfer residual toner scraped off easily moves downward due to gravity, and the amount of escape in the longitudinal direction of the cleaning blade is not large. However, in a configuration in which the cleaning blade is arranged above the photoconductor as in a downsized image forming apparatus, the transfer residual toner scraped off cannot escape downward, and therefore, most of them are longer than the cleaning blade. It escapes in the direction, leaks to the outside of the cleaning means and falls, which causes deterioration of toner scattering in the apparatus.

In order to prevent the toner from scattering, there is a technique of attaching side seals to both end faces of the cleaning blade in the longitudinal direction. However, as shown in FIG. 5, the conventional side seals have corrosion on both end faces of the cleaning blade in the longitudinal direction. By being stuck together, the gap is eliminated and toner leakage is prevented. In the case of a cleaning blade of the type in which the urethane rubber blade is fixed to the holder sheet metal with hot melt or an adhesive, the end surface deviation between the blade rubber and the holder sheet metal is usually 0 to 1 mm. In order to guarantee the bite of the product, it is necessary to bite it in advance and attach the side seal. Actually, since there are variations in other parts, the stacking tolerance of the above gap is approximately ± 0.92 mm, and it is necessary to bite it by 1.84 mm or more and attach the side seal to ensure that there is no gap.

However, when the thickness of the side seal is 8 mm or less, the size of the side seal deformed by a bite of 1.84 mm or more reaches a non-negligible level. The side seal is greatly deformed in the lateral direction to reduce the apparent thickness, and the adhesion to the photoconductor is impaired, causing toner leakage. Further, since the stress on the end surface of the cleaning blade becomes large, that is, the stress becomes large, the straightness of the blade edge cannot be maintained, and the contact condition of the cleaning blade to the photosensitive member becomes uneven, which causes an influence. , Causing toner leakage from a portion where the contact pressure is low. Also,
In recent years, it is difficult to set the thickness of the side seals to 8 mm or more due to layout restrictions because of the demand for space saving due to downsizing of the image forming apparatus. Normally, a sealing material having a thickness of 3 to 4 mm is used. Is generally used.

On the other hand, if the cleaning blade is of a fixed type (no swing), the cleaning device may be independently discarded depending on its life. If the entire image forming cartridge, in which the cleaning unit, some or all of the photoconductor, the charging unit, and the developing unit are integrated, is replaced with a new one, after installing the cleaning blade, By accurately sticking the side seal while properly biting so that there is no gap in accordance with the attached cleaning blade end surface, it is possible to prevent toner leakage without considering the above blade end surface variation.

[0006]

However, in recent years when environmental problems have been attracting attention, instead of discarding the cleaning device or the image forming cartridge as a whole, a life component such as a cleaning blade, a photoconductor or a charging roller or a developer is used. Since it is becoming necessary to reuse the image forming cartridge by replacing the cleaning blade or replenishing the toner, in such a case, the side seal is replaced with a new cleaning blade every time the cleaning blade is replaced. It must be reattached according to the position of the end face of. The side seal is attached to the frame of the image forming cartridge with double-sided tape, but if you remove the attached one, the side seal will deform and the adhesive strength of the double-sided tape will decrease, making it difficult to reuse the side seal. is there.

Therefore, every time the cleaning blade is replaced, the side seals at both ends of the blade must be replaced with new ones, resulting in an increase in cost. In addition, since a large amount of the residual transfer toner that has been collected is present around the side seals, when reattaching the side seals, it causes contamination due to toner scattering to the surroundings, and it also scatters on the side seal sticking surface. If the toner is not completely wiped off, the adhesive strength of the seal will decrease, and re-installation of the side seal will be a very troublesome work, which will increase the maintenance time and downtime of the machine, which will be a disadvantage to the user. There are problems such as.

In view of the above problems, it is an object of the present invention to provide an image forming apparatus which prevents toner from leaking out of the photoconductor cleaning means, increases the cost of parts replacement, and saves the labor of maintenance.

[0009]

In order to solve the above-mentioned problems, the present invention according to claim 1 provides a drum-shaped photosensitive member which is rotatably driven with a rotating shaft supported in a substantially horizontal direction, and the photosensitive member. Charging means arranged along the lateral side surface of the photoconductor to uniformly charge the photoconductor, optical writing means arranged downstream of the charging means in the rotational direction of the photoconductor to record image information on the photoconductor, and optical writing Developing means for developing the electrostatic latent image on the photoconductor formed by the means, transfer means for transferring the developed image formed on the photoconductor to a transfer paper, and at least one counter located above the photoconductor. In an electrophotographic image forming apparatus having an image forming unit including a cleaning means for removing transfer residual toner on the photoconductor from the photoconductor, the both ends of the cleaning blade in the longitudinal direction are provided. The foamed polyurethane of the side seal provided, the side seals and an image forming apparatus, characterized in that in contact with the contact edge of the cleaning blade and the photoreceptor. The present invention according to claim 2 is the image forming apparatus according to claim 1, wherein the side seal made of foamed polyurethane is provided with a skin layer on the photoconductor contact surface. The present invention according to claim 3 provides the image forming apparatus according to claim 1 or 2, wherein the foamed polyurethane foam forming the side seal is a closed cell or a semi-closed cell. The present invention according to claim 4 is the image forming apparatus according to any one of claims 1 to 3, wherein the foamed polyurethane foam forming the side seal has a diameter of 150 μm or less. The invention according to claim 5 is the image forming apparatus according to claim 1, wherein the side seal has an outer shape in which a non-contact portion with the blade edge is enlarged.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of an image forming unit provided in the image forming apparatus of the present invention. The image forming unit in FIG. 1 is a drum-shaped photoconductor 1 that rotates in the direction of the arrow in the figure.
And a charging device as charging means for the photoconductor 1, and the photoconductor 1
A writing device as an optical writing means for recording image information on a recording medium, a developing device as a developing means for developing an electrostatic latent image on the photoconductor 1 formed by the writing device, and a cleaning device for cleaning the photoconductor. It has and. Transfer means 5 are arranged on the lateral side surface of the photoconductor 1 so as to face each other, and the transport path of the transfer paper extends substantially vertically.

FIG. 2 is a side view for explaining the cleaning device of the present invention, and FIG. 3 is a plan view of the cleaning blade of FIG. 2 seen from below. The cleaning blade contacts the photoconductor in the counter direction and is arranged above the photoconductor 1. The cleaning blade according to the present invention includes a blade rubber 3 and a holder metal plate 2. The material of the blade rubber 3 is polyurethane rubber, and is adhered to a metal holder sheet metal 2 such as zinc-treated steel plate by an adhesive material such as hot melt. Blade back seal 4 is PE
Made of flexible sheet material such as T and polyurethane,
One side in the width direction (the left side in FIG. 2) is adhered to the image forming cartridge frame 8 with a double-sided tape. The other protruding side (the right side in FIG. 2) is free, and at least after the photoconductor 1 is mounted, the free protruding portion is bent and the surface of the blade rubber 3 opposite to the photoconductor 1 (see FIG. By closely contacting the image forming cartridge frame 8 and the cleaning blade (the blade rubber 3 and the holder sheet metal 2), the toner leakage is prevented.

Further, both longitudinal ends of the blade back seal 4 overlap the small side seals 5a / 5b. The small side seals 5a / 5b are fixed to the image forming cartridge frame 8, and the blade back seal 4 is compressed and brought into close contact with each other, so that the small side seals 5a / 5b form the image forming cartridge frame 8 and the cleaning blade (blade rubber 3 and The space between the holder metal plates 2) is sealed to prevent toner leakage from both ends in the longitudinal direction.

The side seals 6a / 6b are attached to the image forming cartridge frame 8 by a double-sided tape so as to face the contact edges of the blade rubber 3 at both ends in the longitudinal direction with the photoconductor 1. Since the displacement of the position of the contact edge between the blade rubber 3 and the photoconductor 1 has a great influence on the performance of toner cleaning, strict tolerances are set for the dimensions that determine the position of the edge of each component. For example, the tolerance from the positioning part of the holder sheet metal 2 to the edge is ± 0.1 m.
m. Therefore, as compared with the case where the side seals are attached so as to face both end faces in the longitudinal direction of the cleaning blade in which the end surface deviation between the blade rubber 3 and the holder sheet metal 2 is 0 to 1 mm, the length of the cleaning blade of the side seals 6a / 6b is longer. The amount of bite into both end faces in the direction can be set small.
According to the calculation by the inventor of the present invention, when the side seals 6a / 6b are attached so as to face the contact edges of the blade rubber 3 at both ends in the longitudinal direction with the photoconductor 1, the stacking tolerance of the gap is ± 0. In order to ensure that there is no gap, the side seal may be pasted by cutting into 0.94 mm or more in advance. This can be about half of the bite amount (1.84 mm) in the case of pasting on both end faces in the conventional direction, so that the seal thickness can be 4 mm,
Space saving can be realized, and since it is not necessary to change the side seal every time the blade is replaced, cost and resources can be saved.

Since the small side seals 5a / 5b and the side seals 6a / 6b are made of foamed polyurethane and have appropriate flexibility which is more flexible than the blade rubber 3 with which they abut, the blade rubber 3 It is possible to prevent the blade rubber 3 from being deformed without applying a contact pressure to such an extent that it bends, and to maintain good adhesion with the contact edge with the photoconductor 1. Further, by providing the skin layer on the photoconductor contact surface of the side seals 6a / 6b, the toner that has penetrated into the side seals 6a / 6b can be prevented from exuding to the photoconductor side, and the toner sealing property can be kept good. be able to.

If the material of the side seals 6a / 6b is made of polyurethane foam, and if the bubbles of the foam are open cells (a structure in which there is no wall at the boundary between the bubbles), the toner that has entered the bubbles forms bubbles. From the side seal 6a / to the bubbles because the toner easily penetrates into the foam.
The amount of toner that oozes out of 6b reaches a level that cannot be ignored. Therefore, the side seals 6a / 6b
It is desirable that the foam of the foam used for is a closed cell (a structure with a wall at the boundary between the cells) or a semi-closed foam (a structure with a hole at the boundary between the cells but with a wall remaining). .

If the size of the bubbles is larger than φ150 μm, the unevenness of the surface of the side seals 6a / 6b becomes large, so that it becomes difficult to maintain good adhesion with the edges of the side seals and the sealing performance is impaired. Get lost. In addition, the toner that has entered the bubbles easily moves from bubble to bubble, and the amount of toner that exudes outside the seal reaches a level that cannot be ignored, so the size of the bubble is φ15.
It is preferably 0 μm or less.

As shown in FIG. 3, the side seals 6a / 6b are quadrangular, and a part of the upper side of the quadrangle (6a is the right half and 6b is the left half) is in contact with the blade edge. If so, the side seals 6a / 6b are subjected to stress in the direction of rotation of the photoconductor (upward in FIG. 3) due to friction with the photoconductor. The stress is received by the blade at the contact portion with the blade edge, but since the non-contact portion continues to receive the stress, only the non-contact portion plastically deforms upward or cracks in the deformed portion over time. Occasionally, or the attached double-sided tape creeps and the attachment position shifts. In order to prevent such deformation and displacement of the non-contact portions of the side seals 6a / 6b, the side seal 6 shown in FIG.
It is effective to expand the outer shape of the non-contact portion to the outer side of both end surfaces of the blade as in c / 6d, and to increase the attachment area of the double-sided tape to strengthen the restraint of the non-contact portion.

[0018]

As described above, according to the first aspect of the present invention, the side seal is made of foamed polyurethane which is more flexible and moderately flexible than the blade rubber of the cleaning blade. Thus, it is possible to provide an image forming apparatus capable of maintaining good adhesion to the edge of the cleaning blade without deforming the blade rubber and preventing toner leakage. Further, according to the present invention as set forth in claim 2, by providing the skin layer on the photoconductor contact surface of the side seal, it is possible to prevent the toner that has penetrated into the side seal from exuding to the photoconductor side. An image forming apparatus capable of preventing leakage can be provided. Further, according to the present invention as set forth in claim 3, by making the foamed polyurethane foam forming the side seal into a closed cell or a semi-closed cell, the toner hardly penetrates into the side seal and the inside of the side seal is prevented. It is possible to provide an image forming apparatus capable of preventing toner from leaking through. Further, according to the present invention as set forth in claim 4, the size (diameter) of the foamed polyurethane foam forming the side seal is φ150 μm or less, so that the adhesion between the side seal and the edge of the cleaning blade is good. Therefore, it is possible to provide an image forming apparatus capable of keeping toner leakage and preventing toner leakage. Further, according to the present invention as set forth in claim 5, by enlarging the outer shape of the non-contact portion of the side seal with the blade edge and enlarging the attachment area of the double-sided tape, the side seal can be restrained more strongly. It is possible to provide an image forming apparatus capable of preventing the side seal from being plastically deformed over time, cracks in the deformed portion, and displacement of the sticking position.

[Brief description of drawings]

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

FIG. 2 is a side view showing a cleaning device of the present invention.

FIG. 3 is a plan view showing the shapes of a cleaning blade and side seals of the present invention.

FIG. 4 is a plan view showing the shapes of a cleaning blade and side seals of the present invention.

FIG. 5 is a plan view showing the shapes of a conventional cleaning blade and side seals.

[Explanation of symbols]

1 photoconductor 2 Holder sheet metal 3 blade rubber 4 Blade back seal 5a, 5b Small side seal 6a, 6b Side seal 7 entrance seal 8 frames

Claims (5)

[Claims] 1. A drum-shaped photoconductor that is rotatably driven with a rotation shaft supported in a substantially horizontal direction, a charging unit arranged along a lateral side surface of the photoconductor to uniformly charge the photoconductor, and a charging unit. An optical writing unit that is arranged on the downstream side of the photosensitive member in the rotation direction of the photosensitive member to record image information on the photosensitive member; a developing unit that develops the electrostatic latent image formed on the photosensitive member by the optical writing unit; A transfer unit that transfers a developed image formed on a transfer sheet to the transfer sheet, and a cleaning blade that is located above the photoconductor and that has at least one counter-type cleaning blade, and removes transfer residual toner on the photoconductor from the photoconductor. In the electrophotographic image forming apparatus, the side seals made of polyurethane foam are provided at both ends of the cleaning blade in the longitudinal direction. An image forming apparatus, characterized in that in contact with the contact edge of the blade and the photoreceptor. 2. A side seal made of foamed polyurethane is
The image forming apparatus according to claim 1, wherein a skin layer is provided on the photoconductor contact surface. 3. The image forming apparatus according to claim 1, wherein the foamed polyurethane foam forming the side seal is a closed-cell foam or a semi-closed-cell foam. 4. The image forming apparatus according to claim 1, wherein the foamed polyurethane foam forming the side seal has a diameter of 150 μm or less. 5. The image forming apparatus according to claim 1, wherein the side seal has an outer shape in which a non-contact portion with the blade edge is enlarged.