JPH08248776A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device capable of making the heaping of toner on a separating pawl hard by uniformly and stably coating an image carrier with an adequate quantity of lubricant. CONSTITUTION: A lubricant coating means 23 is provided with a roller type coating member 25 supported by a case 20, a supporting member 27 and a spring 28 which fixedly support a solid lubricant 26 and press it against the outer periphery of the coating member 25 and a scraper member 29 coming into slidable contact with the outer periphery of the coating member 25, to regulate the film thickness of the lubricant. The coating member 25 is rotated in the direction shown by the arrow to be coated with the lubricant from the solid lubricant 26 coming into contact with the coating member 25, so that a thin layer of the lubricant is formed on the surface of the coating member. The lubricant which is laminated on the coating member 25 once is extended/ scraped by the scraper member 29 and a cleaning brush 22, but the lubricant on the surface of the coating member is not removed. The surface of the image carrier is coated with a part of the lubricant concerned with the cleaning brush 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer or a facsimile machine. The present invention relates to an image forming apparatus that improves separation performance of transfer paper and prevents toner from accumulating on a separation claw.

[0002]

2. Description of the Related Art FIG. 4 shows an example of the structure of an image forming unit of an image forming apparatus using an electrophotographic process such as a conventional copying machine, printer, facsimile apparatus and the like. In this image forming unit, the image carrier 1 is uniformly charged in advance by the transfer charger 2 and the surface of the image carrier 1 is irradiated with optical image information from the exposure optical system 3 so that the electrostatic latent image is formed. An image is formed. The eraser 4 removes unnecessary electric charges in the non-image area such as the inter-transfer sheet area and both ends of the transfer sheet, and the developing device 5 supplies toner to the electrostatic latent image to visualize it. The transfer charger 6 transfers the toner image on the image carrier by charging the transfer paper by corona discharge,
Further, the separation charger 7 discharges the transfer paper by corona discharge to facilitate separation of the transfer paper electrostatically adsorbed on the image carrier 1 via the toner image. When a situation occurs in which the transfer paper cannot be separated from the surface of the image carrier, the transfer paper enters the cleaning device 9 and damages the surface of the image carrier. Therefore, the separation claw 10 is provided to prevent this.
After the transfer, the separated transfer paper is conveyed to the fixing device,
It is fixed by heat and pressure. The toner remaining on the image carrier without being transferred in the transfer step is removed by the cleaning device 9. After the toner is removed, the image carrier 1 is electrostatically initialized by being irradiated with light from the charge eliminating lamp 16 and is repeatedly used.

In the image forming section as described above, transfer residual toner and reversely charged toner remain on the image carrier 1 after the transfer is completed, and these toners are scraped off by the separating claw 10. When the separation claw 10 is continuously used for a long period of time, toner accumulates on the separation claw and these drop on the transfer paper, resulting in deterioration of image quality. Further, the separation performance of the separation charger alone is not sufficient to separate the transfer paper from the image carrier, and when the transfer paper comes into contact with the separation claw, toner may adhere to the leading edge of the transfer paper. .

In order to solve such a problem, in Japanese Unexamined Patent Publication No. 3-36577, separation is performed by controlling a pre-transfer exposure lamp according to copying conditions, transfer paper conditions, and temperature conditions. Techniques have been proposed that prevent performance deterioration and image quality deterioration due to poor separation. Further, JP-A-5-142951 includes means for detecting the position where the transfer paper is separated from the image carrier, and changes and controls the separation condition when separating the transfer paper from the image carrier based on the detection result. A technique for properly separating the transfer paper is disclosed. However, if the separation ability due to curvature separation is low due to the large diameter of the image carrier, the linear velocity of the image carrier is high, or the rigidity of the transfer paper is low, the above conditions are changed. Even if you do, you will not get enough results. That is, as described above, in many cases, it is difficult to perform complete separation by the separation method that depends only on the electrostatic force, so that a mechanical separation mechanism using a separation claw has to be adopted. Moreover, when the separation claw is used, toner is accumulated on the tip of the claw, and the accumulated toner adheres to the transfer paper to form a separation claw mark, resulting in a situation in which the image quality is deteriorated.

In Japanese Patent Laid-Open No. 3-182785, a means for removing toner is provided at a position near the tip of the separation claw when the separation claw is displaced from the operating position to the inoperative position or the opposite direction. Discloses a technique for preventing the transfer paper from becoming dirty due to the transfer from the separation claw, but this technique also cannot exhibit a sufficient cleaning effect, and the separation claw is used for the toner in a short time. Since it becomes dirty due to adhesion, it is not possible to prevent dirt on the leading edge of the transfer paper.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an image forming apparatus in which an appropriate amount of a lubricant is uniformly and stably applied to an image carrier to prevent toner from accumulating on the separation claw. It is intended to be provided. Also, to provide an image forming apparatus in which an appropriate amount of a lubricant is uniformly and stably applied only to a portion of the surface of an image carrier corresponding to a separation claw so as not to deteriorate the separation performance of transfer paper. It is an object.

[0007]

To achieve the above object, the invention according to claim 1 is an image carrier for holding a toner image, a transfer means for transferring the toner image on the image carrier onto a transfer paper, and the image carrier. An image forming apparatus having a separation claw that comes into contact with an image carrier to separate the transfer paper from the body, is provided with a lubricant applying means for uniformly and stably applying an appropriate amount of lubricant to the surface of the image carrier. It is characterized by According to a second aspect of the present invention, the lubricant applying means applies the lubricant to at least the image carrier portion corresponding to the separation claw.

[0008]

According to the first aspect of the invention, the image bearing member is constituted so that a proper amount of the lubricant is applied uniformly and stably, so that the friction coefficient of the surface of the image bearing member is lowered. As a result,
When the electrostatic latent image on the image carrier is developed by the toner from the developing device, the extra background stain toner adhering to the background portion is scraped off. In addition, a small amount of the lubricant also adheres to the surface of the toner to reduce the degree of aggregation of the toner. This makes it difficult for the toner to be deposited on the separation claw, and prevents the toner from falling onto the transfer paper and the formation of the separation claw mark on the tip of the transfer paper.

According to the second aspect of the invention, the lubricant is applied to at least the portion corresponding to the separating claw. That is, since the background toner is appropriately present in the portion other than the separation claw, the adhesion between the image carrier and the transfer paper is not so high and the peeling is easy, so that the separation performance is not deteriorated. The same effect as that of the item 1 can be obtained.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 is an explanatory view of a main part configuration of an image forming apparatus to which the present invention is applied, FIG. 2 is a view showing a main part configuration of FIG. 1, and FIG. 3 is an enlarged perspective view of the main part of FIG. In each figure, the same parts as those in the conventional example of FIG. The cleaning device 9 has a configuration in which a case 20 supports a cleaning blade 21, a cleaning brush (medium applying member) 22, and a lubricant applying unit 23. As is well known, the cleaning blade 21 slidably contacts the surface of the photoconductor 1 to scrape off the residual toner, and the cleaning brush 22 which is a brush roller has a brush 22b on the outer periphery of a shaft 22a.

The lubricant applying means 23 of the present invention comprises a roller-shaped applying member 25 supported by the case 20 so that the outer peripheral surface of the cleaning brush 22 is brought into pressure contact with the tip of the brush 22b of the cleaning brush 22 by a predetermined pressure contact force, and solid lubrication. A support member 27 and a spring 28 for fixedly supporting the agent 26 and pressing the solid lubricant 26 toward the outer peripheral surface of the coating member 25;
It has a scraper member 29 and the like that is in sliding contact with the outer peripheral surface of the coating member 25 to regulate the film thickness of the lubricant. The coating member 25 is driven in the arrow direction.

When the coating member 25 rotates in the direction of the arrow, the lubricant is applied from the solid lubricant 26 that contacts the coating member 25, and a thin layer of the lubricant is formed on the surface of the coating member. The lubricant once laminated on the coating member 25 is stretched by the scraper member 29 and the cleaning brush 22 and scraped off at the same time, but the lubricant on the surface of the coating member is not removed. A part of the lubricant on the surface of the coating member is coated on the surface of the image carrier through the cleaning brush 22. This lubricant applied to the image bearing member is a necessary minimum amount and is applied uniformly and stably. Therefore, the friction coefficient of the surface of the image bearing member is lowered to achieve the intended purpose of the present invention. It is possible to do.

As the coating member 25, for example, φ1
6mm stainless steel roller with surface roughness of about 5μ
As the cleaning brush (medium applying member) 22, for example, a brush roller in which a looped brush of polyester fiber having a bristle length of 6 mm is wound around an aluminum cylinder having an outer diameter of 13 mm is used. As the scraper member 29, for example, a plate-shaped polyurethane rubber having a thickness of 1.5 mm and a length of 20 mm is used. However, the above materials, shapes and dimensions are merely examples,
It is not intended to be limited to this. Therefore, for example, the coating member 25 may be various metals, rubbers, foaming resins, or those whose surfaces are coated with another material. Also, the cleaning brush 22 is not limited to the material, the form, the thickness of the fiber, the length of the bristle, the number of twists, the biting material, and the like. The materials and characteristics of all members are not uniformly determined, but relative to the uncertain factors such as the hardness and surface roughness of the image bearing member and other contact members, or the system characteristics of the image forming apparatus itself. It should be selected based on the physical relationship.

Here, the amount of biting by the pressure contact between the cleaning brush 22 and the image carrier 1 is 2.5 mm, and the amount of biting between the cleaning brush 22 and the coating member 25 is 1, 5 mm. The method of pressurizing the lubricant 26 toward the coating member 25 is not limited to the method using the coil spring described above, and a pressing method using a leaf spring or other elastic member may be employed. Any method may be used as long as it is a pressurizing method capable of obtaining a uniform pressing force over substantially the entire length.

The solid lubricant (dry solid hydrophobic lubricant) usable in the present invention includes, for example, zinc stearate, barium stearate, lead stearate,
Iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate, zinc oleate, manganese oleate, iron oleate, cobalt oleate,
Lead oleate, magnesium oleate, copper oleate, palmitic acid, zinc cobalt palmitate, copper palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate,
Lead caproate, zinc linolenate, cobalt linolenate,
Mention may be made of relatively higher fatty acids such as calcium linolenate or cadmium lycorinoneate, eg colloidal high temperature silica powders such as Ca-O-S11 commercially available from Kapot Corporation. Natural waxes such as carnauba wax are also effective.

FIG. 3 is a schematic diagram showing the positional relationship between the coating member 25 and the separating claw 10 (see FIG. 3). The two solid lubricants 26 are both downstream corresponding to the separating claw 10 located on the upstream side. It is arranged at the side position, and the lubricant is applied around the surface of the photoconductor 1 with which the separation claw 10 is in contact. Therefore, it is possible to prevent the toner from accumulating on the separation claw and the deterioration of the separation performance.

In the above embodiment, the lubricant applying means for applying the lubricant to the surface of the photoconductor 1 has been exemplified, but the lubricant is applied on the intermediate transfer member (intermediate transfer belt). Good. That is, the intermediate transfer member is used in a color copying machine or the like, and it receives the toner image on the photosensitive member, temporarily holds it, and then collectively transfers it onto the transfer paper at a predetermined timing. This is because the intermediate transfer member also uses a separating claw for peeling off the transfer paper in this intermediate transfer member as in the case of the photosensitive member, and the same problem as in the case of the photosensitive member occurs.

[0018]

As described above, according to the invention of claim 1,
An image having an image carrier that holds a toner image, a transfer unit that transfers the toner image on the image carrier onto a transfer paper, and a separation claw that contacts the image carrier to separate the transfer paper from the carrier. Since the forming apparatus is provided with the lubricant applying means for uniformly and stably applying the appropriate amount of the lubricant to the surface of the image carrier, the background toner on the image carrier is reduced and the toner is aggregated. The amount of toner deposited on the separation claw can be significantly reduced. As a result, it is possible to prevent the toner from falling onto the transfer paper and the situation where a separation claw mark is formed at the tip of the transfer paper.

According to the second aspect of the present invention, the lubricant applying means applies the lubricant to at least the image bearing member portion corresponding to the separation claw, so that the separation performance is not deteriorated and the image is not deteriorated. It is possible to reduce the amount of background stain toner on the carrier, reduce the degree of toner aggregation, and significantly reduce the amount of toner deposited on the separation claw. As a result, it is possible to prevent the toner from falling onto the transfer paper and the situation where a separation claw mark is formed at the tip of the transfer paper.

[Brief description of drawings]

FIG. 1 is a diagram showing a main configuration of an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a main part of FIG.

FIG. 3 is a perspective view showing a further main part of FIG.

FIG. 4 is a structural explanatory view of a conventional example which is a premise of the present invention.

[Explanation of symbols]

1 image carrier, 2 transfer charger, 3 exposure optical system,
4 eraser, 5 developing device, 6 transfer charger, 7
Separation Charger, 9 Cleaning Device, 10 Separation Claw, 20 Case, 21 Cleaning Blade, 22
Cleaning brush (mediating application member), 23 lubricant applying means, 25 applying member, 26 solid lubricant, 27
Support member, 28 spring, 29 scraper member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michikuni 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Masato Yanagida 1-3-6 Nakamagome, Ota-ku, Tokyo No. Stock Company Ricoh

Claims (2)

[Claims] 1. An image carrier for holding a toner image, transfer means for transferring the toner image on the image carrier onto a transfer paper, and contact with the image carrier for separating the transfer paper from the image carrier. An image forming apparatus provided with a separating claw, characterized in that it is provided with a lubricant applying means for uniformly and stably applying an appropriate amount of lubricant to the surface of the image carrier. 2. The image forming apparatus according to claim 1, wherein the lubricant applying unit applies the lubricant to at least an image carrier portion corresponding to the separation claw.