JP6929614B2 - Develop equipment, process cartridges and image forming equipment - Google Patents

Description

The present invention relates to a developing apparatus used in an electrophotographic image forming apparatus.

In an image forming apparatus such as a copier, a printer, or a facsimile, which forms an image on a recording material by using an electrophotographic image forming method (electrophotographic process), the electrophotographic photosensitive member as an image carrier is used in the image forming step. An electrostatic image is formed, and the electrostatic image is developed with a developer. The developing apparatus responsible for the developing step in the image forming step may be configured to be detachably attached to the apparatus main body of the image forming apparatus as an independent unit or as a part of a process cartridge. The developing device is rotatably arranged in a frame body called a developing container or the like that stores toner as a developing agent and an opening of the frame body, and by rotating, the toner is supported and conveyed from the inside of the frame body to the outside. It includes a developing roller as a developer carrier. The developing apparatus further includes a developing blade as a regulating member that comes into contact with the surface of the developing roller in order to regulate the amount of toner that is supported by the developing roller and passes through the opening, and a frame in which the toner is supported and conveyed by the developing roller. It is provided with various sealing members to prevent leakage to the outside. Various sealing members include end sealing members (also referred to as end peripheral surface sealing members) for preventing toner leakage around both ends in the axial direction (longitudinal direction) of the rotating shaft of the developing roller at the opening.

The end sealing member is a flexible sealing member whose surface to be rubbed against the developing roller is made of felt, pile fabric, or the like. The end sealing member is attached to each of the seating surfaces provided at both ends of the opening in the longitudinal direction, and is between the frame, the back surface of the developing blade, and the peripheral surface of the developing roller at both ends of the opening in the longitudinal direction. Seal the gap. The end sealing member is provided so as to be in close contact with the end of the developing roller and to press the developing blade against the developing roller. The end sealing member is generally configured to obtain a repulsive force and secure the sealing property by compressing and deforming the portion overlapping the developing blade with a predetermined crushing amount.

Here, in Patent Document 1, the thickness of the toner layer on the developing roller is constant in the developing blade which extends from one end fixed to the frame in the direction opposite to the rotation direction of the developing roller and the other end contacts the surface of the developing roller. The following configurations have been proposed to regulate the amount. That is, a pressure contacting portion that is in pressure contact with the developing roller and a facing portion that is formed so as to face the developing roller on the upstream side in the rotational direction of the developing roller away from the developing roller. And, it is a configuration having. According to this configuration, a toner pool is stably formed between the surface of the developing roller and the surface of the developing roller at the facing portion on the upstream side of the pressure contact portion in the rotation direction of the developing roller, and the toner pressure immediately before the layer regulation is made uniform. A uniform toner layer can be stably obtained.

Japanese Unexamined Patent Publication No. 11-2702067

In recent years, the speed of image formation and the extension of life have progressed, and it has become more important to achieve both a reduction in contact pressure with the developing roller at the end of the developing blade and a sealing property that fills the gap. Due to the high speed of image formation, the frictional heat between the developing roller and the developing blade becomes large, and toner fusion on the developing roller and the developing blade is more likely to occur as compared with the conventional case. When a fused product of toner is formed on the contact surface between the developing roller and the developing blade, a gap is formed between the developing roller and the developing blade, which may cause toner leakage. Therefore, it is preferable that the contact pressure at the end of the developing blade with the developing roller is lower.

However, in the above configuration in which the developing blades overlap on the end sealing member, when a developing blade having a shape defined as in Patent Document 1 is used, toner is applied at the rubbing portion between the developing blade end and the developing roller. Toner leakage due to fusion may occur. At the portion where the developing blade overlaps the end sealing member, the contact pressure with respect to the developing roller increases due to the repulsive force of the end sealing member. Due to this increase in contact pressure, toner may be fused to the end of the developing blade or the developing roller, and a gap may be formed between the end of the developing blade and the developing roller.

Further, when a developing blade having a defined shape as in Patent Document 1 is used, the contact pressure with respect to the developing roller increases at the stepped portion between the pressure contact portion and the facing portion as compared with the flat developing blade, so that the developing blade melts. Toner leakage due to adhesion may worsen. Further, due to the extension of the life of the cartridge, higher sealing performance is required for the seal between the end sealing member, the developing blade, and the developing roller. At this time, if the repulsive force of the end sealing member is not sufficient, the toner may enter the above-mentioned gap and the toner may leak.

An object of the present invention is to provide a technique capable of effectively suppressing the occurrence of toner leakage due to toner fusion with a simple configuration.

In order to achieve the above object, the developing apparatus of the present invention
A developing device used in an image forming device.
A frame that houses the developer and
A developer carrier that is rotatably provided in the opening of the frame and that carries and conveys the developer.
A blade-shaped regulating member that comes into contact with the developer carrier in order to regulate the amount of the developer carried on the developer carrier, and one end of the frame does not move relative to the frame. is secured to, Ri free end der the Ru extending in a direction opposite to the rotational direction of the other end said developer carrying member, a regulating member to which the other end is in contact with the developer carrier,
An end sealing member that is attached to the seating surfaces provided at both ends of the opening, adheres to the end of the developer carrier, and presses the regulating member against the developer carrier.
With
The regulatory member
In the portion facing the developer carrier, a convex portion protruding toward the developer carrier is provided at a distance from the tip of the other end.
When the cross section perpendicular to the rotation axis of the developer carrier is viewed in a state where the end sealing member is not assembled to the frame, the facing portion is the tip of the other end of the convex portion. The side portion has the closest contact portion closest to the developer carrier and has a closest contact portion.
The distance from the seating surface to the closest contacting portion in the virtual line connecting the seating surface and the center of rotation of the developer carrier through the closest contacting portion is D1 (mm), and the developing agent from the seating surface. When the distance to the surface of the carrier is D2 (mm),
0.79 ≤ D1 / D2 ≤ 0.96
It is characterized in that it is assembled to the frame body so as to satisfy the above conditions.
In order to achieve the above object, the process cartridge of the present invention is
A process cartridge that can be attached to and detached from the main body of the image forming device.
With the above developing device
An image carrier on which a latent image developed by the developing device is formed, and
It is characterized by having.
In order to achieve the above object, the image forming apparatus of the present invention
An image forming device that forms an image on a recording material.
With the above developing device
An image carrier on which a latent image developed by the developing device is formed, and
With
The latent image is developed and the developer image formed on the image carrier is transferred to a recording material.

According to the present invention, the occurrence of toner leakage due to toner fusion can be effectively suppressed by a simple configuration.

Schematic cross-sectional view of the image forming apparatus according to the first embodiment. Schematic cross-sectional view of the process cartridge according to the first embodiment Schematic cross-sectional view of the vicinity of the end of the developing roller in Example 1. Configuration explanatory view of the vicinity of the end peripheral surface sealing member pasting seat surface in the first embodiment Schematic cross-sectional view of the end peripheral surface sealing member according to the first embodiment. Explanatory drawing of shape of developing blade in Example 1 Explanatory drawing of shape of developing blade in Example 1 Dimensional relationship explanatory view in the vicinity of the end peripheral surface sealing member pasting seat surface in the first embodiment Explanatory drawing of positional relationship between development blade and development roller in Example 1.

Hereinafter, embodiments for carrying out the present invention will be described in detail exemplarily based on examples with reference to the drawings. However, the dimensions, materials, shapes, etc. of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

(Example 1)
<1-1>: Overall schematic configuration of the image forming apparatus With reference to FIG. 1, the overall configuration of the electrophotographic image forming apparatus (hereinafter, image forming apparatus) according to the embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view of the image forming apparatus 100 of this embodiment. The image forming apparatus 100 of this embodiment is a full-color laser printer that employs an in-line method and an intermediate transfer method. The image forming apparatus 100 can form a full-color image on a recording material (for example, recording paper, plastic sheet, cloth, etc.) according to the image information. The image information is input to the image forming apparatus main body 100A from a host device such as an image reading device connected to the image forming apparatus main body 100A or a personal computer communicably connected to the image forming apparatus main body 100A.

The image forming apparatus 100 forms first, second, and third images of each color of yellow (Y), magenta (M), cyan (C), and black (K) as a plurality of image forming units, respectively. , Has a fourth image forming unit SY, SM, SC, SK. In this embodiment, the first to fourth image forming portions SY, SM, SC, and SK are arranged in a row in a direction intersecting the vertical direction. In this embodiment, the configurations and operations of the first to fourth image forming units SY, SM, SC, and SK are substantially the same except that the colors of the formed images are different. Therefore, in the following, if no particular distinction is required, the subscripts Y, M, C, and K given to the code to indicate that the element is provided for any of the colors are omitted, and the whole is summarized. explain.

In this embodiment, the image forming apparatus 100 has four drum-type electrophotographic photosensitive members arranged side by side in a direction intersecting the vertical direction, that is, a photosensitive drum 1, as a plurality of image carriers. The photosensitive drum 1 is rotationally driven in the direction of arrow A (clockwise) by a drive means (drive source) (not shown). Around the photosensitive drum 1, a charging roller 2 as a charging means for uniformly charging the surface of the photosensitive drum 1, and an electrostatic image (electrostatic latent image) on the photosensitive drum 1 by irradiating a laser based on image information. A scanner unit (exposure device) 3 is arranged as an exposure means for forming the above. Further, around the photosensitive drum 1, a developing unit (developer) 4 as a developing means for developing an electrostatic image as a toner image (developer image), and transfer residual toner remaining on the surface of the photosensitive drum 1 after transfer. A cleaning member 6 is arranged as a cleaning means for removing the above. Further, an intermediate transfer belt 5 as an intermediate transfer body for transferring the toner image on the photosensitive drum 1 to the recording material 12 is arranged above the photosensitive drum 1 so as to face the four photosensitive drums 1.

In this embodiment, the developing unit 4 as a developing device uses a toner of a non-magnetic one-component developer as a developing agent. Further, in this embodiment, the developing unit 4 performs reverse development by bringing a developing roller as a developing agent carrier into contact with the photosensitive drum 1. That is, in this embodiment, the developing unit 4 is a portion (image unit) in which the toner charged with the same polarity as the charging polarity of the photosensitive drum 1 (negative electrode property in this embodiment) is charged by exposure on the photosensitive drum 1. , The exposed part) to develop the electrostatic image.

In this embodiment, the photosensitive drum 1 and the charging roller 2, the developing unit 4, and the cleaning member 6 as process means acting on the photosensitive drum 1 are integrated, that is, integrally made into a cartridge, and the process cartridge is formed. 7 is formed. The process cartridge 7 can be attached to and detached from the image forming apparatus 100 via mounting means such as a mounting guide and a positioning member provided on the image forming apparatus main body 100A. In this embodiment, the process cartridges 7 for each color all have the same shape, and the process cartridges 7 for each color contain yellow (Y), magenta (M), cyan (C), and blanks, respectively. The toner of each color of K) is stored. Further, in this embodiment, a non-magnetic one-component toner is used as the developer.

The intermediate transfer belt 5 formed of the endless belt as the intermediate transfer body abuts on all the photosensitive drums 1 and circulates (rotates) in the direction of arrow B (counterclockwise) in the drawing. The intermediate transfer belt 5 is hung on the drive roller 51, the secondary transfer opposed roller 52, and the driven roller 53 as a plurality of support members. On the inner peripheral surface side of the intermediate transfer belt 5, four primary transfer rollers 8 as primary transfer means are arranged side by side so as to face each photosensitive drum 1. The primary transfer roller 8 presses the intermediate transfer belt 5 toward the photosensitive drum 1 to form a primary transfer portion N1 in which the intermediate transfer belt 5 and the photosensitive drum 1 come into contact with each other. Then, a bias having a polarity opposite to the normal charging polarity of the toner is applied to the primary transfer roller 8 from a primary transfer bias power supply (high voltage power supply) as a primary transfer bias applying means (not shown). As a result, the toner image on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 5.

Further, a secondary transfer roller 9 as a secondary transfer means is arranged at a position facing the secondary transfer facing roller 52 on the outer peripheral surface side of the intermediate transfer belt 5. The secondary transfer roller 9 is pressed against the secondary transfer opposed roller 52 via the intermediate transfer belt 5 to form a secondary transfer portion N2 in which the intermediate transfer belt 5 and the secondary transfer roller 9 come into contact with each other. Then, a bias having a polarity opposite to the normal charging polarity of the toner is applied to the secondary transfer roller 9 from a secondary transfer bias power supply (high pressure power supply) as a secondary transfer bias applying means (not shown). As a result, the toner image on the intermediate transfer belt 5 is transferred (secondary transfer) to the recording material 12.

For example, when forming a full-color image, the above-mentioned processes up to the primary transfer are sequentially performed in the first to fourth image forming units SY, SM, SC, and SK, and a toner image of each color is formed on the intermediate transfer belt 5. Next, they are overlaid and primary transferred. After that, the recording material 12 is conveyed to the secondary transfer unit N2 in synchronization with the movement of the intermediate transfer belt 5. The four-color toner image on the intermediate transfer belt 5 is collectively secondarily transferred onto the recording material 12 by the action of the secondary transfer roller 9 which is in contact with the intermediate transfer belt 5 via the recording material 12. The recording material 12 on which the toner image is transferred is conveyed to the fixing device 10 as a fixing means. By applying heat and pressure to the recording material 12 in the fixing device 10, the toner image is fixed to the recording material 12.

The primary transfer residual toner remaining on the photosensitive drum 1 after the primary transfer step is removed and recovered by the cleaning member 6. Further, the secondary transfer residual toner remaining on the intermediate transfer belt 5 after the secondary transfer step is cleaned by the intermediate transfer belt cleaning device 11. The image forming apparatus 100 can also form a monochromatic or multicolor image by using only one desired image forming unit or using only some (but not all) image forming units. It has become like.

<1-2>: Schematic configuration of the process cartridge With reference to FIG. 2, the overall configuration of the process cartridge 7 mounted on the image forming apparatus 100 of this embodiment will be described. In this embodiment, the configuration and operation of the process cartridge 7 for each color are substantially the same except for the type (color) of the stored toner. FIG. 2 is a schematic cross-sectional view (main cross section) of the process cartridge 7 of the present embodiment as viewed along the longitudinal direction (rotational axis direction) of the photosensitive drum 1. The posture of the process cartridge 7 in FIG. 2 is a posture in a state of being mounted on the image forming apparatus main body, and when the positional relationship and direction of each member of the process cartridge are described below, the positional relationship and direction in this posture. Etc. are shown.

The process cartridge 7 is configured by integrating a photoconductor unit 13 including a photosensitive drum 1 and the like and a developing unit 4 including a developing roller 17 and the like. The photoconductor unit 13 has a cleaning frame body 14 as a frame body that supports various elements in the photoconductor unit 13. A photosensitive drum 1 is rotatably attached to the cleaning frame 14 via a bearing (not shown). The photosensitive drum 1 is rotationally driven in the direction of arrow A (clockwise) according to the image forming operation by transmitting the driving force of a drive motor as a drive means (drive source) (not shown) to the photoconductor unit 13. NS. In this embodiment, the photosensitive drum 1 which is the center of the image forming process is an organic photosensitive drum 1 in which an undercoat layer, a carrier generation layer, and a carrier transfer layer, which are functional films, are sequentially coated on the outer peripheral surface of an aluminum cylinder. I am using it.

Further, in the photoconductor unit 13, a cleaning member 6 and a charging roller 2 are arranged so as to come into contact with the peripheral surface of the photosensitive drum 1. The transfer residual toner removed from the surface of the photosensitive drum 1 by the cleaning member 6 is dropped and accommodated in the cleaning frame 14. The charging roller 2, which is a charging means, rotates drivenly by bringing the roller portion of the conductive rubber into pressure contact with the photosensitive drum 1. Here, a predetermined DC voltage is applied to the photosensitive drum 1 as a charging step on the core metal of the charging roller 2, whereby a uniform dark potential (Vd) is applied to the surface of the photosensitive drum 1. Is formed. The spot pattern of the laser light emitted in response to the image data by the laser light from the scanner unit 3 described above exposes the photosensitive drum 1, and the exposed portion is charged by the carriers from the carrier generation layer. It disappears and the potential drops. As a result, an electrostatic latent image having a predetermined bright area potential (Vl) in the exposed area and a predetermined dark area potential (Vd) in the unexposed area is formed on the photosensitive drum 1. In this embodiment, Vd = −500V and Vl = −100V.

<1-3>: Description of the developing unit The developing unit 4 includes a developing roller 17 as a developer carrier for supporting the toner 80, a toner supply roller 20 as a supply member for supplying toner to the developing roller 17, and a toner. A stirring transfer member 22 as a transfer member for transporting the 80 to the toner supply roller 20 is provided. The developing unit 4 includes a developing container 18 as a frame into which a developing roller 17, a toner supply roller 20, and a stirring and transporting member 22 are rotatably assembled. In the developing container 18, the toner can move between the toner accommodating chamber 18a in which the stirring and transporting member 22 is arranged, the developing chamber 18b in which the developing roller 17 and the toner supply roller 20 are arranged, and the toner accommodating chamber 18a and the developing chamber 18b. It has a communication port 18c, which communicates with each other as much as possible. The developing chamber 18b is provided with a developing opening 30b as an opening for carrying the toner to the outside of the developing container 18, and the developing roller 17 is rotatably assembled to the developing container 18 in an arrangement that closes the developing opening 30b. ing. That is, the toner contained in the developing container 18 is carried and conveyed by the rotating developing roller 17 to pass through the developing opening 30b and move to the outside of the developing container 18 to develop the electrostatic latent image of the photosensitive drum 1. Will be offered to. At that time, the amount of toner carried out of the developing container 18 is regulated and adjusted by the developing blade 21. The toner accommodating chamber 18a is located below the developing chamber 18b in the direction of gravity. The position where the developing blade 21 comes into contact with the developing roller 17 is located below the center of rotation of the developing roller 17 and between the center of rotation of the developing roller 17 and the center of rotation of the toner supply roller 20 in the horizontal direction.

The stirring and transporting member 22 stirs the toner stored in the toner accommodating chamber 18a and conveys the toner toward the upper part of the toner supply roller 20 in the developing chamber 18b in the direction of arrow G in the drawing. In this embodiment, the stirring and transporting member 22 is driven and rotated at a rotation speed of 60 rpm. The developing roller 17 and the photosensitive drum 1 rotate so that their surfaces move in the same direction (in this embodiment, from the bottom to the top) at the facing portions. In this embodiment, the developing roller 17 is arranged in contact with the photosensitive drum 1, but the developing roller 17 may be arranged close to the photosensitive drum 1 at a predetermined interval. good. In this embodiment, the toner negatively charged by triboelectric charging with respect to the predetermined DC bias applied to the developing roller 17 is brought into the bright potential portion from the potential difference in the developing portion in contact with the photosensitive drum 1. Only the transition is made to visualize the electrostatic latent image. In this embodiment, by applying V = −300V to the developing roller, a potential difference ΔV = 200V from the bright potential portion is formed, and a toner image is formed.

The surfaces of the toner supply roller 20 and the developing roller rotate in a direction in which the surfaces of the toner supply roller 20 and the developing roller move from the upper end to the lower end of the nip portion N. That is, the toner supply roller 20 rotates in the direction of arrow E (clockwise) in the drawing, and the developing roller 17 rotates in the direction of arrow D. The toner supply roller 20 is an elastic sponge roller having a foam layer formed on the outer periphery of the conductive core metal. The toner supply roller 20 and the developing roller 17 are in contact with each other with a predetermined amount of penetration, that is, in FIG. 2, the toner supply roller 20 has a recessed amount ΔE that is made concave by the developing roller 17. The toner supply roller 20 and the developing roller 17 rotate in the nip portion N in the same direction with a peripheral speed difference (the peripheral surface of the toner supply roller 20 moves faster than the peripheral surface of the developing roller 17). do). By this operation, the toner supply roller 20 supplies toner to the developing roller 17. At that time, the amount of toner supplied to the developing roller can be adjusted by adjusting the potential difference between the toner supply roller and the developing roller.

In this embodiment, the toner supply roller is driven and rotated at a rotation speed of 300 rpm and the developing roller is driven at a rotation speed of 200 rpm, and a DC bias is applied to the developing roller so that the toner supply roller becomes Δ-50V. That is, V = −300V is applied to the developing roller, and V = −350V is applied to the toner supply roller. By doing so, the toner can be easily supplied from the toner supply roller to the developing roller. In this embodiment, both the developing roller 17 and the toner supply roller 20 have an outer diameter of 15 mm, and the amount of penetration of the toner supply roller 20 into the developing roller 17, that is, the toner supply roller 20 is concave due to the developing roller 17. The dent amount ΔE, which is said to be, was set to 1.0 mm. Further, the toner supply roller and the developing roller are arranged so that the center heights are the same.

<1-4>: Seal configuration of the developing unit The toner seal configuration of the developing unit 4 in this embodiment will be described with reference to FIGS. 3 and 4. FIG. 3A is a schematic cross-sectional view showing the configuration of the developing unit 4 around the end portion of the developing roller 17 in the rotation axis direction (longitudinal direction), and FIG. 3B is FIG. 3A. It is an enlarged view around the tip of the developing blade. FIG. 4 is a schematic view illustrating the dimensional relationship in the longitudinal direction (direction of the rotation axis of the developing roller 17) in the configuration around the mounting seat surface of the peripheral peripheral surface sealing member, and is perpendicular to the rotation axis of the developing roller 17. The dimensional relationship of each member is shown in the direction. It should be noted that each drawing for explaining this embodiment schematically shows each member in order to make it easier to understand the apparatus configuration, and does not strictly show the dimensional relationship between them.

As shown in FIG. 3A, at both ends in the longitudinal direction of the developing opening 30b of the developing container 18 in which the developing roller 17 is arranged, the seating surface 41 on which the end sealing member 40 is attached is the rotation axis of the developing roller 17. It is formed in a form including an arc-shaped surface centered on. An end seal member (hereinafter, end seal) 40, which is a flexible member such as a pile whose surface is woven with felt or fibers and electrostatic flocking, is attached to the seat surface 41. A part of the end seal 40 overlaps with the developing blade 21 in the longitudinal direction, and a gap between the developing opening 30b and the back surface of the developing blade 21 (the surface opposite to the contact surface of the developing blade 21 with the developing roller 17). Is filling. That is, the end seal 40 has a structure in which (the end portion) of the developing blade 21 is interposed between the developing roller 17 and a part of the portion facing the developing roller 17, and the sealing surface thereof is the developing roller. Not only the peripheral surface of 17 is contacted, but also a part of the developing blade 21 is contacted. By pressure-contacting the end seal 40 with the peripheral surface of the developing roller 17 and the back surface of the developing blade 21, toner is provided in the longitudinal direction not only between the peripheral surface of the developing roller 17 but also between the back surface of the developing blade 21. Is prevented from leaking.

As shown in FIG. 4, the developing blade 21 overlaps the end seal 40 at the end in the region II. Here, the widths (lengths) of the developing rollers 17, the developing blades 21, and the end seals 40 used in this embodiment in the longitudinal direction are 235.6 mm, 226 mm, and 4.8 mm, respectively. The developing roller 17 and the developing blade 21 are arranged with reference to the center in the longitudinal direction (the positions of the midpoints in the longitudinal direction match), and the end of the developing blade 21 is 4.8 mm inside the end of the developing roller 17 in the longitudinal direction. Located in. The end seal 40 is arranged so that the outer end in the longitudinal direction is located 2.0 mm inward in the longitudinal direction with respect to the end of the developing roller 17, and the inner end in the longitudinal direction is located with respect to the end of the developing blade 21. It is located 2.0 mm inward in the longitudinal direction. That is, the end seal 40 overlaps the developing blade 21 in the longitudinal direction by 2.0 mm (region II). With this overlapping configuration, the region I formed by the developing blade 21, the developing roller 17, and the end seal 40 shown in FIG. 3B is the end seal 40 compressed by the developing roller 17 and the developing blade 21. , It is filled by pressing against them. A predetermined sealing property can be obtained between the developing blade 21 and the developing roller 17 by pressing the developing blade 21 against the developing roller 17 by receiving the pressure contact force of the end seal 40 at the overlapping portion.

FIG. 5 is a schematic cross-sectional view illustrating the cross-sectional configuration of the end seal member 40 in this embodiment, and is shown in a flat shape state before being attached to the seat surface 41. As shown in FIG. 5, the end sealing member 40 of this embodiment is composed of three layers of a surface layer 40a, an intermediate layer 40b, and an adhesive layer 40c. The surface layer 40a is a layer made of pile woven fabric, having a thickness of 1.9 mm and a JIS-A hardness of 34 °. The intermediate layer 40b is a layer made of a foam layer, made of urethane foam, having a thickness of 3.0 mm, and having a JIS-A hardness of 12 °. The adhesive layer 40c is a layer made of double-sided tape and having a thickness of 0.05 mm.

<1-5>: Configuration of the developing blade in the present embodiment The configuration of the developing blade 21 in the present embodiment will be described in detail with reference to FIG. FIG. 6 is a schematic cross-sectional view for explaining the shape of the developing blade 21 in this embodiment. The regulation blade 21 is a blade-like member having a support member 21a and a resin layer 21b integrally attached to the tip end side of the support member 21a. One end of the support member 21a in the lateral direction is fixed to the developing container 18 by a fastener such as a screw, and the other end is a free end of the cantilever. That is, in the developing blade 21, the other end of the support member 21a becomes the base end of the developing blade 21, and one end of the supporting member 21a on which the resin layer 21b is formed is in sliding contact with the developing roller 17. It becomes the tip. The tip end side of the support member 21a faces upstream in the rotation direction of the developing roller 17. That is, the developing blade 21 is arranged so as to face the counter direction with respect to the rotation of the developing roller 17.

The toner is triboelectrically charged by rubbing between the developing blade 21 and the developing roller 17, and is charged, and at the same time, the layer thickness is regulated. Further, in this embodiment, a predetermined voltage is applied to the developing blade 21 from a blade bias power supply (not shown) to stabilize the toner coating. In this embodiment, V = −500V is applied as the blade bias.

The support member 21a is a plate-shaped elastic member. For the support member 21a, a thin metal plate (sheet metal) was used and stainless steel was used in order to have elasticity (springiness). However, in addition to stainless steel, phosphor bronze, aluminum alloy, or the like may be used. In this embodiment, the support member 21a uses a sheet metal having a width of 226 mm in the longitudinal direction, a width of 9.6 mm in the lateral direction orthogonal to the longitudinal direction, and a thickness of 0.08 mm.

The resin layer 21b is the other end of the support member 21a from the side facing the developing roller 17 on the support member 21a to the side facing the end seal 40 through the tip of the other end. It is formed to cover the part. The resin layer 21b was produced by coating the support member 21a with polyurethane. In addition, the material of the resin layer 21b may be a polyamide, a polyamide elastomer, a polyester, a polyester elastomer, a polyester terephthalate, a silicone rubber, a silicone resin, or a melamine resin, or may be used alone or in combination of two or more. Further, these materials may contain various additives such as coarse particles, if necessary. Further, a metal may be used for the coat layer.

In addition to the coating method adopted this time, the resin layer 21b can be roughly divided into a method of directly forming (integral molding) on the support member 21a and a method of forming the resin layer 21b in advance and adhering it to the support member 21a. .. As a method of forming the resin layer 21b directly on the support member 21a, there are a method of extruding a raw material on the support member 21a and a method of applying the resin layer 21b to a thin metal plate by dipping, coating, spraying or the like. Further, as a method of forming the resin layer 21b in advance, there are a method of cutting out a sheet prepared from a raw material and a method of forming the resin layer 21b with a mold or the like.

In the resin layer 21b, the convex portion 21b1 protruding toward the developing roller 17 is predetermined from the tip (the other end side of the support member 21a, the upstream side in the rotational direction of the developing roller 17) at the portion facing the developing roller 17. It is provided at a distance. The facing portion 21b2 on the tip side of the convex portion 21b1, that is, on the upstream side in the rotational direction of the developing roller 17, faces the developing roller 17 via a predetermined space. The side of the convex portion 21b1 opposite to the tip end side (base end side of the developing blade 21), that is, the downstream side in the rotational direction of the developing roller 17, is formed in a planar shape facing the developing roller 17 via a predetermined space. It is a straight portion 21b3.

Here, the height of the step between the convex portion 21b1 and the facing portion 21b2 (the height of the convex portion 21b1), that is, the pressure contact surface that presses against the developing roller 17 on the developing blade 21, and the developing roller rather than the pressure contact surface. Let H (mm) be the distance from the facing surface that takes a distance from 17. Further, the length of the facing portion 21b2 in the lateral direction is L (mm). Further, the tip surface of the convex portion 21b1 when viewed in the contact radius of the convex portion 21b1 of the developing blade 21 that abuts on the developing roller 17, that is, the cross section perpendicular to the rotation axis of the developing roller 17, that is, the cross section of FIG. The radius of curvature of the arc forming the above is R (mm). The radius of curvature R is preferably 1.00 mm or more so that the developing blade 21 can stably contact the developing roller 17 with a constant contact width.

7A and 7B are schematic cross-sectional views for explaining the shape of the developing blade in the modified example of this embodiment, in which FIG. 7A is a modified example 1 and FIG. 7B is a modified example 2. As the configuration of the developing blade 21 to which the present invention is applied, various configurations can be adopted as shown in FIG. 7 for the other portions as long as the facing portion 21b2 described above is provided. As shown in FIG. 6, in the first embodiment, the straight portion 21b3 is configured to be lower than the convex portion 21b1 (so as to keep a distance from the developing roller 17), whereas in FIG. 7A, the straight portion 21b3 is configured to be lower than the convex portion 21b1. In the first modification, the straight portion 21b3 is formed at the same height as the convex portion 21b1. Further, in the modified example 2 of FIG. 7B, a second convex portion lower than the convex portion 21b1 is formed in the opposing portion 21b2 on the tip side of the convex portion 21b1. In this configuration, the tip of the second convex portion is the closest contact portion with the developing roller 17 in the facing portion 21b2 of the developing blade 21, which will be described later.

8A and 8B are schematic views for explaining the positional relationship and the dimensional relationship between the developing blade 21, the developing roller 17, and the end peripheral surface sealing member pasting seat surface 41. FIG. The positional relationship and dimensional relationship of each member in Example 2 (FIG. 7 (b)) are shown. Note that FIG. 8 schematically shows each member in order to make it easier to understand the device configuration, and does not strictly show the dimensional relationship between them. In this embodiment, as shown in FIG. 8, the distance between the seat surface 41 and the tip of the developing blade 21 is D1 (mm), and the distance between the surface of the developing roller 17 is D2 (mm). These D1 and D2 are the distances when the end seal 40 is removed, and connect the center of the developing roller 17 and the closest contact portion with the developing roller 17 in the facing portion 21b2 on the tip side of the convex portion 21b1 of the developing blade 21. It shall be on a virtual straight line. That is, D1 and D2 are distances when the cross section perpendicular to the rotation axis of the developing roller 17 is viewed in a state where the end seal 40 is not assembled to the developing container 18. D1 passes through the closest contact portion closest to the developing roller 17 at the portion of the developing blade 21 facing the developing roller 17 on the tip side of the convex portion 21b1 and passes through the seat surface 41 and the rotation center of the developing roller 17. It is the distance from the seat surface 41 to the closest contact portion in the connecting virtual line. D2 is the distance from the seat surface 41 to the surface of the developing roller 17 in the virtual line.

In this embodiment, D1 = 1.9 (mm) and D2 = 2.2 (mm). Then, the height H of the convex portion 21b1 of the developing blade 21 is 0.1 (mm), the length L of the opposing portion 21b2 is 0.3 (mm), and the contact radius R of the convex portion 21b1 is 1.0 (mm). ), No image defect (ghost image) occurred, and no toner leakage occurred.

<1-6>: Experiment contents The following experiments were performed in the configuration of this example. In the configuration of this example, some values of D1 and D2 described above were assigned to perform a toner leakage experiment. The contact radius R of the convex portion 21b1 of the developing blade 21 was fixed to 1.0 mm, and a sample was prepared by swinging the height H of the convex portion 21b1 and the length L of the opposing portion 21b2.

A method of changing D1 and D2 will be described with reference to FIGS. 8 and 9. FIG. 9 is a schematic view illustrating the positional relationship and the dimensional relationship between the developing blade 21, the developing roller 17, the end sealing member 40, and the seat surface 41. Consider a coordinate system in a cross section perpendicular to the rotation axis of the developing roller 17 as shown in FIG. That is, in the above cross section, the direction substantially parallel to the extending direction of the developing blade 21 in the state of being pressed against the developing roller 17 by the end seal 40 is defined as the y-axis, and the direction perpendicular to the y-axis is defined as the x-axis. The origin is the rotation center O of the developing roller 17, and the center coordinates of the developing roller 17 are (x, y) = (0,0). In this coordinate system, the position of the developing blade tip 21b in the y-axis direction is defined as the Y value. When changing D1, it was done by changing the above Y value. Further, D1 was also changed by changing the height H of the convex portion 21b1 of the developing blade 21 and the length L of the facing portion 21b2. D2 was changed by scraping the seat surface 41 and changing the distance between the seat surface 41 and the developing roller 17. Of course, if the seat surface 41 is scraped, D1 will also be changed.

The device in which the above dimensional settings are assembled with various values is left overnight in an environment of high temperature and high humidity (30 ° C., 80% Rh), and after being sufficiently acclimatized to the environment, an experimental image is formed on a recording material. Image formation was performed intermittently on 10,000 recording materials, and the presence or absence of toner leakage was compared. Intermittent paper is a paper that prints once, waits for the next print, and then prints the next print. In this example, as an experimental image, an image in which horizontal lines with an image printing rate of 0.5% appear periodically was used.

＜表２＞本実施例におけるトナー漏れ評価の結果

<1-7> Experimental Results Tables 1 and 2 show the setting and evaluation results of this example. In Table 2, ◯ indicates that no toner leakage has occurred, and × indicates that toner leakage has occurred.
<Table 1> Toner leakage evaluation settings in this embodiment

<Table 2> Results of toner leakage evaluation in this example

The experiment was carried out by shaking D1 (mm) to 1.68 to 2.15 mm and D2 (mm) to 2.20 to 4.00 mm, and the following results were obtained.
When D1 / D2 is 0.76 or less, toner leakage has occurred.
When D1 / D2 is 0.79 to 0.96, no toner leakage has occurred.
-When D1 / D2 is 0.98 or more, toner leakage has occurred.
Therefore, from these experimental results, it was found that the appropriate ratio of D1 and D2 is in the following range.
0.79 ≤ D1 / D2 ≤ 0.96
Therefore, if the configuration in the above range is adopted, it is possible to improve toner leakage due to toner fusion while suppressing the occurrence of image defects (ghost images).

<1-8>: Effect of improving toner leakage The effects of this example were verified below. The contact pressure with respect to the developing roller 17 at the portion of the developing blade 21 where the end seals 40 overlap (the portion of the developing blade 21 that is pressed against the developing roller 17 by the repulsive force of the end seal 40) was measured. .. For the contact pressure at the end of the developing blade 21, the developing device from which the developing roller 17 is removed is attached to a dedicated measuring jig, and the developing blade 21 is applied to an aluminum sleeve having the same diameter as the developing roller 17 as a virtual developing roller. Make contact and measure. The length of the stylus is 50 mm, and the contact pressure of the developing blade is calculated from the average value at the two measurement points at both ends. Below, Table 3 shows the relationship between D1 / D2, D2-D1 and the contact pressure in this embodiment. In this embodiment, D1 / D2 is shaken from 0.76 to 0.98 for verification.
<Table 3> Relationship between D1 / D2, D2-D1 and contact pressure in this embodiment

The mechanism for improving toner leakage in this embodiment will be described with reference to FIGS. 3 and 8. In the toner leakage, the contact pressure of the developing blade 21 with respect to the developing roller 17 increases due to the repulsive force of the end seal 40, and the toner is fused to the end of the developing blade 21 and the developing roller 17, so that the developing blade 21 The cause is that a gap is generated between the end portion and the developing roller 17. In the above experiment, toner leakage occurred when D2-D1> 0.47. On the other hand, if the contact pressure with respect to the developing roller 17 at the end of the developing blade 21 is too low, toner enters the gap between the end seal 40, the developing blade 21, and the developing roller 17, and toner leakage occurs. In the above experiment, toner leakage occurred when D2-D1 <0.09. Therefore, in FIG. 8, when the value of D1 / D2 is low, the contact pressure of the developing blade 21 with respect to the developing roller 17 increases, and toner leakage occurs. Further, when the value of D1 / D2 is high, the contact pressure of the developing blade 21 with respect to the developing roller 17 decreases, and the toner penetrates into the gap between the end seal 40, the developing blade 21, and the developing roller 17 in FIG. , Toner leakage occurs.

From the above results,
0.79 ≤ D1 / D2 ≤ 0.96
or,
0.09 ≤ D2-D1 ≤ 0.47
Each member is designed and assembled so as to satisfy the relationship of. As a result, when the pressure contact pressure of the portion of the developing blade 21 pressed against the developing roller 17 by the end seal 40 with respect to the developing roller 17 is X (gf / cm).
15 ≤ X ≤ 58
Relationship can be satisfied.

In this embodiment, as the end seal 40, an end seal member having a structure as shown in FIG. 5 is used, but the present invention is not limited to this. The end where D1 / D2 is in the range of 0.79 to 0.96, or D2-D1 is in the range of 0.09 to 0.47, and the contact pressure is 15 (gf / cm) to 58 (gf / cm). As long as it is a partial seal member, an end seal member having another structure may be used.

According to the developing blade 21 of this embodiment, even if the distance of D1 is changed, a toner pool is stably formed in the facing portion on the upstream side of the developing roller 17 in the rotational direction with respect to the convex portion 21b1, and the toner immediately before the layer regulation is formed. The pressure becomes uniform, and a uniform toner layer can be stably obtained. On the other hand, in the case of a flat developing blade, it is not preferable to change D1 to improve toner leakage because a uniform toner layer cannot be stably obtained by changing the distance of D1.

As described above, according to the developing blade 21 of this embodiment, the ratio of D1 and D2 may be in the range of 0.79 ≦ D1 / D2 ≦ 0.96 or 0.09 ≦ D2-D1 ≦ 0.47. For example, it is possible to improve toner leakage while suppressing the occurrence of image defects (ghost images).

Although the present embodiment illustrates an image forming apparatus capable of forming a color image, the present invention is not limited thereto. In a configuration in which a toner supply roller using a non-magnetic one-component toner rotates in the same direction as the developing roller, the same effect can be obtained even with an image forming apparatus capable of forming a monochrome image. Further, in the present embodiment, a printer is exemplified as an image forming apparatus, but the present invention is not limited thereto. The present invention is also applicable to other image forming devices such as a copier, a facsimile machine, or a multifunction device combining these functions.

4 ... Development unit (development device), 17 ... Development roller, 18 ... Development container (frame), 20 ... Toner supply roller (supply member), 21 ... Development blade (regulatory member), 21b ... Development blade tip, 21b1 ... Convex part, 21b2 ... Opposite part, 30b ... Development opening (opening), 40 ... End peripheral surface sealing member (end sealing member), 41 ... End peripheral surface sealing member pasting seat surface

Claims (12)

A developing device used in an image forming device.
A frame that houses the developer and
A developer carrier that is rotatably provided in the opening of the frame and that carries and conveys the developer.
A blade-shaped regulating member that comes into contact with the developer carrier in order to regulate the amount of the developer carried on the developer carrier, and one end of the frame does not move relative to the frame. is secured to, Ri free end der the Ru extending in a direction opposite to the rotational direction of the other end said developer carrying member, a regulating member to which the other end is in contact with the developer carrier,
An end sealing member that is attached to the seating surfaces provided at both ends of the opening, adheres to the end of the developer carrier, and presses the regulating member against the developer carrier.
With
The regulatory member
In the portion facing the developer carrier, a convex portion protruding toward the developer carrier is provided at a distance from the tip of the other end.
When the cross section perpendicular to the rotation axis of the developer carrier is viewed in a state where the end sealing member is not assembled to the frame, the facing portion is the tip of the other end of the convex portion. The side portion has the closest contact portion closest to the developer carrier and has a closest contact portion.
In the virtual line connecting the seat surface and the center of rotation of the developer carrier through the closest contact portion, the distance from the seat surface to the closest contact portion is D1 (mm), and the developer is formed from the seat surface. When the distance to the surface of the carrier is D2 (mm),
0.79 ≤ D1 / D2 ≤ 0.96
A developing apparatus characterized in that it is assembled to the frame body so as to satisfy the above conditions. 0.09 ≤ D2-D1 ≤ 0.47
The developing apparatus according to claim 1, wherein the relationship between the two is satisfied. When the pressure contact pressure of the portion of the regulating member pressed against the developer carrier by the end sealing member with respect to the developer carrier is X (gf / cm).
15 ≤ X ≤ 58
The developing apparatus according to claim 1 or 2, wherein the relationship of the above is satisfied. The developing apparatus according to any one of claims 1 to 3, wherein the closest contact portion is the tip of the other end. The regulating member according to any one of claims 1 to 3, wherein a second convex portion lower than the convex portion is provided on the tip end side of the other end of the convex portion. Developing equipment. The developing apparatus according to claim 5, wherein the closest contact portion is the tip of the second convex portion. In order to supply the developer to the developer carrier, a supply member provided on the frame so as to contact and rotate the developer carrier is further provided.
The position where the restricting member comes into contact with the developer carrier is below the center of rotation of the developer carrier and in the horizontal direction between the center of rotation of the developer carrier and the center of rotation of the supply member. The developing apparatus according to any one of claims 1 to 6, wherein the developing apparatus is located. The regulating member has an elastic support member and a resin layer provided on the surface of the support member and in contact with the developer carrier.
The developing apparatus according to any one of claims 1 to 7, wherein the convex portion is integrally molded as a part of the resin layer. The developing apparatus according to any one of claims 1 to 8, wherein the developing agent is a non-magnetic one-component toner. A process cartridge that can be attached to and detached from the main body of the image forming device.
The developing apparatus according to any one of claims 1 to 9,
An image carrier on which a latent image developed by the developing device is formed, and
A process cartridge characterized by being equipped with. An image forming device that forms an image on a recording material.
The developing apparatus according to any one of claims 1 to 9,
An image carrier on which a latent image developed by the developing device is formed, and
With
An image forming apparatus, characterized in that the latent image is developed and a developer image formed on the image carrier is transferred to a recording material. It is characterized by further including an intermediate transfer body which is arranged above the image carrier and the developer image formed on the image carrier is transferred and the transferred developer image is transferred to the recording material. The image forming apparatus according to claim 11.

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