JP4712565B2 - Lubricant coating apparatus, process cartridge, and image forming apparatus - Google Patents

Description

The present invention relates to a lubricant application device that forms a thin layer of lubricant by applying a lubricant to the surface of an image carrier, and a process cartridge and an image forming apparatus including the lubricant application device.

As an image forming Engineering in an electrophotographic image forming apparatus to form an electrostatic latent image on a photosensitive member as an image bearing member using a photoconductive phenomenon, the toner particles colored in the electrostatic latent image It refers to the process of making a visible image by applying electrostatic force. In an image forming apparatus that employs such an electrophotographic system, a lubricant application device that applies a lubricant to the surface of a photoreceptor, which is the main member, is usually provided.
The lubricant application device is used to eliminate a problem that occurs in a cleaning process of an image forming apparatus, for example, a process in which toner remaining on the surface of a photoreceptor after image transfer is scraped with a cleaning brush or a cleaning blade. That is, the life of the photosensitive member and the intermediate transfer belt is mainly determined by the degree of wear due to mechanical friction with the cleaning brush or the cleaning blade, and therefore by applying a lubricant to the surface of the photosensitive member and the intermediate transfer belt. The friction coefficient of the surface is reduced to suppress wear, thereby extending the life.

By applying a lubricant to the surface of the photoconductor, not only the life of the photoconductor is extended, but also the deposits adhering to the surface of the photoconductor are easily cleaned as the coefficient of friction of the surface of the photoconductor decreases. That is, by applying a lubricant to the surface of the photoreceptor, residual toner remaining on the surface of the photoreceptor or intermediate transfer body without being completely transferred to the recording medium or the like in the transfer step can be easily removed by a cleaning brush or a cleaning blade.
By the way, in recent years, spheroidized toners prepared by a polymerization method have been suitably used. However, since spheroidized toners have a uniform particle size distribution and can effectively reduce the particle size, image quality can be improved. While exhibiting the effect of improving, there is a problem that removal of residual toner from the photoreceptor, that is, cleaning becomes difficult. From this point of view, it is considered that a technique for applying a lubricant to the surface of the photosensitive member by a lubricant application device and thereby improving the cleaning property of the photosensitive member will become more important in the future.

The lubricant is applied by supplying a small amount of the lubricant in the form of powder to the surface of the photoreceptor. As a specific application method, for example, as disclosed in Patent Document 1, the lubricant is blocked by an application means such as a brush. And a method of scraping and applying the lubricant formed into a shape. Further, as disclosed in Patent Document 2, there is a method in which a lubricant is externally added to the toner and supplied to the photoreceptor. When the lubricant is externally added to the photoreceptor and the lubricant is supplied to the photoconductor, the supply amount depends on the output image area, so that it is difficult to always supply the lubricant to the entire surface of the photoconductor stably. Therefore, from the viewpoint of stably supplying the lubricant to the entire surface of the photoreceptor, a method of scraping and applying the solid lubricant with a brush is preferable.

When the lubricant is applied to the surface of the photoreceptor, it is important to control the application amount and the application state in order to maximize the two effects of preventing wear and improving the cleaning property. If the emphasis is on imparting lubricity, it is sufficient to continue supplying a certain amount or more of the lubricant, but if the supply amount becomes excessive, excess lubricant is mixed in, for example, a developing device provided adjacently, There may be a problem that the charge amount of the toner cannot be controlled. Further, due to the recent demand for miniaturization of copying machines and printers, miniaturization of each element member is becoming an important technology, and it is not preferable to mount a solid lubricant larger than necessary as equipment.

As a conventional technique for controlling the application state of a lubricant to a photoconductor as an image carrier, for example, Patent Document 3 discloses a pressure of a solid lubricant applied to a photoconductor or a coating brush in contact with the solid lubricant depending on temperature. A technique for controlling the rotation speed is disclosed. Patent Document 4 discloses a technique for defining the amount of lubricant applied per unit rotational speed of the photoreceptor. Further, Patent Document 5 discloses a technique for controlling the number of rotations of the lubricant application brush in accordance with image formation information.

JP 2000-162881 A Japanese Patent No. 2859646 JP-A-9-62163 JP 2000-75752 A JP 2002-24485 A

However, the above prior art avoids inconvenience caused by the accumulation of lubricant powder on the blade holder that supports the lubricant application blade provided adjacent to the lubricant application brush roller in the lubricant application device. The technical idea to be attempted is not shown at all, and a powdery lubricant that is scraped off by a brush roller and falls without being applied to the surface of the photoreceptor as an image carrier is deposited on the blade holder. There is a problem that the powdered lubricant adheres to the surface of the photoreceptor and causes image smearing on images formed thereafter.
FIGS. 7 and 8 are explanatory views showing such a conventional technique. FIG. 7 is a perspective view showing a conventional blade holder applied to a conventional lubricant application device, and FIG. It is sectional drawing of a process cartridge provided with the lubricant application device to which a blade holder is applied.
FIG. 7 shows a blade holder 27 in which no through hole is provided in any of the bent portion 27a and the flat plate portions 27b and 27c. In FIG. 8, the process cartridge 100 is constituted by the photosensitive member 10 and the cleaning device 30, the lubricant applying device 20, the charging device 40, and the developing device 50 arranged around the photosensitive member 10 along the rotation direction. It is configured. The lubricant application device 20 is adjacent to the solid lubricant 21, the brush roller 22 in contact with the solid lubricant 21 and the photoreceptor 10, and the solid lubricant 21 on the downstream side in the rotation direction of the brush roller 22. And a blade holder 27 that supports the coating blade 23 is provided.

In such a lubricant application device, it is subjected to the image forming process for a long period of time, and as a result of repeating the lubricant application operation on the surface of the photoconductor 10, it is scraped off by the brush roller 22 and scattered without being applied to the surface of the photoconductor 10. The powdery lubricant 28 thus deposited may be deposited on the flat plate portion of the blade holder 27.
When the amount of the powdery lubricant deposited on the blade holder 27 exceeds a predetermined amount, the powdery lubricant is attracted between the photoreceptor 10 and the coating blade 23, and an electrically strong history of the photoreceptor 10 remains. In the next image formation, the image is transferred to the transfer belt side or the recording paper side (not shown) and causes the image to become dirty.
The present invention has been made in view of the problems of the prior art, and a powdery lubricant that is scraped off by a brush roller and falls without being applied to the surface of the image carrier is deposited on the blade holder. , And a lubricant application apparatus capable of preventing image smearing caused by the powdery lubricant adhering to the surface of the photoreceptor as a lump, and a process cartridge and an image forming apparatus provided with the lubricant application apparatus It is an issue to provide.

In order to solve the above-described problems, a lubricant application device according to the present invention includes a solid lubricant, a brush roller that contacts the solid lubricant and the image carrier, and applies the lubricant to the surface of the image carrier. the solid lubricant to the adjacent rotating direction downstream side of the brush roller, and provided et the coating blade in contact with the trailing direction with respect to the image carrier, the image carrier surface the coating blade A blade holder disposed below the coating blade and provided so that a contact surface with the coating blade is substantially horizontal, and the image carrier is supported by the brush roller. A lubricant application device for leveling the lubricant applied to the surface with the application blade, wherein the lubricant is scraped off by the brush roller onto the blade holder and dropped onto the blade holder without being applied to the surface of the image carrier. Wherein the through hole powdery lubricant passes is provided.
In this case, the blade holder has a bent section having a saddle shape in cross section, and the through hole can be formed in the bent section along the longitudinal direction of the blade holder.
In addition, the blade holder may have a bent portion having a saddle-shaped cross section, and the through hole may be formed in a flat plate portion adjacent to the bent portion along the longitudinal direction of the blade holder.
In this case, the through holes may be formed uniformly along the longitudinal direction of the blade holder, but the through holes may be formed only at both ends in the longitudinal direction of the blade holder. .

The process cartridge according to the present invention integrally supports an image carrier having an electrostatic latent image carrying surface, and at least one process unit selected from a charging unit, a developing unit, and a cleaning unit. In the process cartridge formed detachably on the main body, the process cartridge is provided with any one of the above-described lubricant application devices.
An image forming apparatus according to the present invention forms an electrostatic latent image by exposing an image carrier, charging means for charging the surface of the image carrier, and exposing the surface of the image carrier based on image information. Via an exposure means, a developing means for supplying a toner to the electrostatic latent image on the surface of the image carrier to make a visible image, an intermediate transfer member that moves while contacting the image carrier, or directly, An image forming apparatus comprising: a transfer unit that transfers the visible image onto a recording medium; and a cleaning unit that collects toner remaining on the surface of the image carrier after the transfer. Any one lubricant applicator or the process cartridge is provided.

According to the present invention, the powdery lubricant that has been scraped off by the brush roller and dropped without being applied to the surface of the image carrier passes through the through-hole provided in the blade holder and falls further downward. There is no accumulation on the holder. Accordingly, it is possible to prevent image contamination due to the powdery lubricant deposited on the blade holder being agglomerated and adhering to the surface of the image carrier.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a perspective view showing a blade holder of a lubricant application device according to a first embodiment of the present invention. In FIG. 1, the blade holder 27 has a bent portion 27a having a bowl-shaped cross section, and a plurality of through holes 29 are provided at equal intervals along the longitudinal direction of the blade holder in the bent portion 27a. The blade holder 27 is made of, for example, a steel plate having a pressure of 1.6 mm, the length in the longitudinal direction of the blade holder 27 is 350 mm, the width of the flat plate portion 27b is 10 mm, and the width of the flat plate portion 27c is 7.5 mm. In this case, the size of the through hole 29 has an elliptical shape with a major axis of 8 mm and a minor axis of 3 mm, for example. In this case, the ratio of the sum total of the opening areas with respect to all the flat plate portions of the blade holder 27 is, for example, 19.5%.
Such a blade holder 27 constitutes a part of a lubricant application device as a support member for supporting the application blade 23, and the lubricant application device to which this blade holder 27 is applied is incorporated in a process cartridge. It becomes a member.

FIG. 2 is a cross-sectional view of a process cartridge incorporating a lubricant application device to which the blade holder 27 of FIG. 1 is applied.
In FIG. 2, the process cartridge 100 includes a photoconductor 10, and a lubricant application device 20, a cleaning device 30, a charging device 40, and a developing device 50 arranged around the photoconductor 10. The cleaning device 30 is provided with a cleaning blade 31 that contacts the surface of the photoreceptor 10. The lubricant application device 20 includes a solid lubricant 21, a lubricant support member 24 that supports the solid lubricant 21, and a lubricant application that rotates in contact with both the solid lubricant 21 and the photoconductor 10. The brush roller 22 is provided. The brush roller 22 applies a powdery lubricant scraped from the solid lubricant 21 to the surface of the photoreceptor 10. An application blade 23 is disposed downstream of the solid lubricant 21 in the rotation direction of the brush roller 22, and the application blade 23 is attached to the blade holder 27 in a state in which a tip portion thereof is in contact with the surface of the photoconductor 10. It is supported. The coating blade 23 levels the lubricant applied to the surface of the photoconductor 10 so that the thickness thereof is uniform. The blade holder 27 is provided with the above-described through hole 29 in the bent portion 27a.

On the other hand, the charging device 40 is mainly composed of a charging roller 41 disposed so as to be in contact with the photosensitive member 10 and a charging roller cleaner 42 that rotates in contact with the charging roller 41. The developing device 50 includes a developing roller 51 that supplies toner as a developer to the surface of the photoreceptor 10 to visualize the electrostatic latent image, and a mixing roller that stirs the developer stored in the developer storage unit. 52 and a supply roller 53 that supplies the stirred and mixed developer to the developing roller 51.
Such a process cartridge is incorporated in an image forming apparatus and used for image formation.

FIG. 3 is a schematic configuration diagram of an image forming apparatus to which the process cartridge of FIG. 2 is applied.
In FIG. 3, the image forming apparatus 200 forms a full color image, and mainly includes a reading unit 110, an image forming unit 120, and a paper feeding unit 130. In the reading unit 110, a first reading traveling body 111, a second reading traveling body 112, an imaging lens 113, and a reading sensor 114 are arranged.
The image forming unit 120 is provided with four process cartridges 121 (Y, C, M, and K), an endless intermediate transfer belt 122, and a secondary transfer roller 123.

The intermediate transfer belt 122 is disposed above the photosensitive member 10 of each process cartridge, and the lower running surface of the intermediate transfer belt 122 is in contact with the peripheral surface of each photosensitive member 10. The configuration in which a toner image is formed on each photoconductor 10 and the toner image is transferred to the intermediate transfer belt 122 is substantially the same in each process cartridge. Below the process cartridge row, an exposure device 60 for irradiating the surface of the charged photoreceptor 10 with laser light to form an electrostatic latent image is disposed.
On the other hand, the paper feed unit 130 is provided with a paper feed cassette 131 for storing transfer paper as a recording medium and a paper feed roller 132. The paper feed roller 132 is connected to the intermediate transfer belt 122 via a registration roller 133. The transfer paper is fed at a predetermined timing toward the nip portion with the next transfer roller 123. In addition, a fixing device 126 is disposed at the outlet of the secondary transfer roller 123, and a paper discharge roller 127 and a paper discharge storage unit 128 that stores the discharged recording paper are provided downstream of the fixing device 126. Is provided.

Hereinafter, the operation of the image forming apparatus having such a configuration will be described.
First, the photosensitive member 10 is rotated clockwise, and the surface thereof is charged to a predetermined polarity by the charging roller of the charging device 40. The charged photoreceptor 10 is irradiated with, for example, a laser beam emitted from the exposure device 60 and subjected to light modulation, thereby forming an electrostatic latent image on the surface of each photoreceptor 10. Each electrostatic latent image is supplied with a developer of each color from the developing roller of the developing device 50, and a toner image corresponding to each developer is formed to make a visible image.
Next, for example, a transfer voltage is applied to a primary transfer roller (not shown) to cause each toner image on the photoreceptor 10 to be primarily transferred onto the intermediate transfer belt 122, and each image is superimposed to form a color image. For example, the color image transferred to the intermediate transfer belt 122 is secondarily transferred onto a recording sheet discharged from the paper supply roller 132 at a predetermined timing. The recording paper on which the color image is secondarily transferred is sent to the fixing device 126, where the color image on the recording paper is fixed on the recording paper. The recording paper on which the color image is fixed is discharged to the paper discharge storage portion 128 by the paper discharge roller 127.
On the other hand, the transfer residual toner remaining on the photoreceptor 10 after the toner image is transferred is collected and removed by the cleaning blade of the cleaning device 30.

Next, a lubricant is applied to the cleaned surface of the photoreceptor 10. That is, the solid lubricant 21 is scraped off and applied to the surface of the photoconductor 10 as a powdery lubricant by the brush roller 22 that rotates in contact with both the solid lubricant 21 and the photoconductor 10 in FIG. The lubricant applied to the surface of the body 10 is uniformly leveled by the downstream application blade 23 to form a lubricant film having a predetermined thickness on the surface of the photoreceptor 10. At this time, a part of the powdery lubricant scraped off by the brush roller 22 is not applied to the surface of the photoreceptor 10 but is blown to the downstream side in the rotation direction by the brush roller 22 and falls onto the blade holder 27. However, as shown in FIGS. 1 and 2, since the through hole 29 for allowing the powdered lubricant to pass through the bent portion 27a of the blade holder 27 is provided, the powdered lubricant is It falls to the lower part through 29. Therefore, the powdery lubricant scraped off by the brush roller 22 does not accumulate on the blade holder 27, so that a lump of powdery lubricant passes on the blade holder 27 on the surface of the photoreceptor 10. Inconvenience due to adhesion is avoided.

According to the present embodiment, by providing a large number of through-holes 29 in the bent portion 27 a of the blade holder 27, it is possible to prevent the powdery lubricant from accumulating on the blade holder 27. Accordingly, it is possible to prevent, for example, image contamination caused by the lump of powdery lubricant adhering to the surface of the photoreceptor 10.
In the present embodiment, it is preferable to provide a lubricant receiver below the blade holder 27 for receiving the powdered lubricant that has passed through the through hole 29 and dropped. Thereby, scattering of the powdery lubricant can be prevented.
In this embodiment, zinc stearate (ZnSt) is suitably used as the lubricant, but calcium stearate (CaSt) or other lubricants can also be used.

In the present invention, the through holes through which the powdery lubricant passes can be formed only at both ends in the longitudinal direction of the blade holder. FIG. 4 is a perspective view showing a blade holder of the lubricant application device according to the second embodiment of the present invention. In FIG. 4, the blade holder 427 is different from the blade holder 27 in FIG. 1 in that through holes 429 are provided only at both ends in the longitudinal direction of the blade holder 427. The ratio with respect to the length of all the blade holders in the length of the part provided with the through holes at both ends is, for example, 20 to 40%.
According to the present embodiment, in the same manner as in the first embodiment, accumulation of powdery lubricant on the blade holder 427 is prevented, and an image resulting from adhesion of the powdery lubricant to the surface of the photoconductor 10 is obtained. Dirt can be prevented.
It is conventionally known that the amount of powder lubricant deposited on the blade holder is the largest at both ends in the longitudinal direction, and only the both ends in the longitudinal direction of the blade holder as in this embodiment. The intended purpose can also be achieved by forming a through-hole.

In the present invention, the through hole through which the powdery lubricant passes can be formed in the flat plate portion adjacent to the bent portion of the blade holder. FIG. 5 is a perspective view showing a blade holder of the lubricant application device according to the third embodiment of the present invention. The blade holder 527 is different from the blade holder 27 of FIG. 1 in that a through hole 529 is provided in a flat plate portion 527b adjacent to the bent portion 527a of the blade holder 527. In the present embodiment, the through hole 529 has a circular shape.
According to the present embodiment, as in the first embodiment, accumulation of powdery lubricant on the coating blade holder 527 can be prevented.

Further, in the present invention, the through-hole through which the powdery lubricant passes can be formed only in the flat plate portion adjacent to the bent portion and at both ends in the longitudinal direction of the blade holder. FIG. 6 is a perspective view showing a blade holder of the lubricant application device according to the fourth embodiment of the present invention. The blade holder 627 differs from the blade holder 527 of FIG. 5 in that through holes 629 are formed only at both ends in the longitudinal direction of the blade holder 627. The ratio with respect to the length of all the blade holders in the length of the part provided with the through holes at both ends is, for example, 20 to 40%.
According to the present embodiment, accumulation of powdery lubricant on the coating blade holder 627 can be prevented in substantially the same manner as in the third embodiment.
Note that it is conventionally known that the amount of powder lubricant deposited on the coating blade holder is the largest at both ends in the longitudinal direction, as in this embodiment, both ends in the longitudinal direction of the coating blade holder. By forming the through hole only in the portion, the intended purpose can be achieved.

Here, the coating blade leveles the lubricant applied to the surface of the photoconductor to form a lubricant film having a uniform thickness, and the blade holder applies the coating blade to the surface of the photoconductor with a predetermined pressing force. It supports and fixes so that it may contact | abut. Therefore, the blade holder is required to have a predetermined strength, but the blade holder is provided with a through-hole for allowing the powdered lubricant that is scraped off by the brush roller and dropped without being applied to the surface of the photoreceptor to pass therethrough. By providing, the strength is reduced, and the maximum displacement of the blade holder when securing a predetermined contact pressure of the coating blade is increased.
That is, when the maximum displacement for maintaining a contact pressure of 0.2 N / cm on the photosensitive member surface 10 of the coating blade in the conventional blade holder of FIG. The maximum displacement of the blade holder in the first embodiment under the same conditions is 2.8, the maximum displacement of the blade holder in the second embodiment is 1.9, the maximum displacement of the blade holder in the third embodiment is 1.2, and the fourth The maximum displacement of the blade holder in the embodiment was 1.1 to 1.2 (1.17).
From this result, it can be seen that it is more preferable to provide the through hole in the flat plate portion along the bent portion of the blade holder in order to reduce the strength reduction of the blade holder as much as possible and prevent the accumulation of the powdery lubricant. .

It is a perspective view of a blade holder applied to a lubricant application device according to an embodiment of the present invention. It is sectional drawing of the process cartridge incorporating the blade holder of FIG. FIG. 3 is a schematic configuration diagram of an image forming apparatus incorporating the process cartridge of FIG. 2. It is a perspective view of the blade holder applied to other embodiment. It is a perspective view of the blade holder applied to another embodiment. Furthermore, it is a perspective view of the blade holder applied to another embodiment. It is a perspective view of the coating blade holder in a prior art. It is sectional drawing of the process cartridge incorporating the conventional blade holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Photosensitive body 20 Lubricant coating device 21 Solid lubricant 22 Brush roller 23 Coating blade 24 Lubricant holding member 25 Lubricant holder 27 Blade holder 27a Bending part 27b Flat plate part 27c Flat plate part 28 Powdery lubricant 29 Through-hole 30 Cleaning device 31 Cleaning Blade 40 Charging Device 41 Charging Roller 42 Charging Roller Cleaner 50 Developing Device 51 Developing Roller 52 Mixing Roller 53 Supply Roller
60 Exposure device 110 Reading unit 111 First reading traveling body 112 Second reading traveling body 113 Imaging lens 114 Reading sensor 120 Image forming unit 121 Process cartridge 122 Intermediate transfer belt 123 Secondary transfer roller 126 Fixing device 127 Paper discharge roller 128 Ejection Paper storage unit 130 Paper feed unit 131 Paper feed cassette 132 Paper feed roller 133 Image forming apparatus 427 Blade holder 427a Bending part 429 Through hole 527 Blade holder 527a Bending part 527b Flat plate part 529 Through hole 627 Blade holder 627b Flat plate part 629 Through hole

Claims (7)

Solid lubricant,
A brush roller that contacts the solid lubricant and the image carrier and applies the lubricant to the surface of the image carrier;
With respect to the solid lubricant, adjacent to the rotation direction downstream side of the brush roller, and provided et the coating blade in contact with the trailing direction with respect to the image carrier,
A blade holder that supports the coating blade in contact with the surface of the image carrier, is disposed below the coating blade, and is provided so that a contact surface with the coating blade is substantially horizontal ; ,
A lubricant application device for leveling the lubricant applied to the surface of the image carrier by the brush roller with the application blade;
Lubricant characterized in that the blade holder is provided with a through hole through which a powdery lubricant that is scraped off by the brush roller and falls on the blade holder without being applied to the surface of the image carrier passes. Coating device. The lubrication according to claim 1, wherein the blade holder has a bent portion having a saddle-shaped cross section, and the through hole is formed in the bent portion along a longitudinal direction of the blade holder. Agent applicator. The blade holder includes a bent portion having a saddle-shaped cross section, and the through hole is formed in a flat plate portion adjacent to the bent portion along a longitudinal direction of the blade holder. 2. The lubricant application device according to 1. The lubricant application device according to claim 2 or 3, wherein the through holes are formed uniformly along a longitudinal direction of the blade holder. The lubricant application device according to claim 2 or 3, wherein the through holes are formed only at both ends in the longitudinal direction of the blade holder. An image carrier having an electrostatic latent image carrying surface;
In a process cartridge which integrally supports at least one process means selected from a charging means, a developing means and a cleaning means, and is detachably formed on the image forming apparatus main body,
The process cartridge includes the lubricant application device according to claim 1. An image carrier;
Charging means for charging the surface of the image carrier;
Exposure means for exposing the surface of the image carrier based on image information to form an electrostatic latent image; and
Developing means for supplying a toner to the electrostatic latent image on the surface of the image bearing member to make a visible image;
A transfer means for transferring the visible image onto a recording medium directly or via an intermediate transfer member that moves in contact with the image carrier;
Cleaning means for recovering toner remaining on the surface of the image carrier after transfer;
In an image forming apparatus comprising:
The image forming apparatus includes the lubricant application device according to any one of claims 1 to 5 or the process cartridge according to claim 6.

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