JP2009223208A - Development apparatus, process cartridge, image forming apparatus, and screwing method for developer regulating member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development apparatus capable of securing a path of laser beams writing an electrostatic latent image to a latent image carrier even if it is miniaturized. <P>SOLUTION: In a development roller 33Yb supplying toner to the electrostatic latent image to carry out development, and the developer regulating member (a doctor blade 33Yg) separated for just a predetermined gap G to regulate thickness of a developer, when screwing the developer regulating member to a developer housing case 33Ya housing the developer, screwing is carried out such that a screw head is positioned in an inner side of the developer housing case 33Ya. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device and a process cartridge used in an electrophotographic image forming apparatus such as a copying machine, a facsimile machine, a printer, and a composite machine of these, and more particularly to a screwing method for a developer regulating member.

  2. Description of the Related Art Conventionally, a developing roller (developer carrying member) carrying a developer on its surface and a doctor blade (developer regulating member) for regulating the developer carried by the developing roller are provided, and an electrostatic latent image on the latent image carrying member is provided. A developing device for converting an image into a toner image with toner of each color and a process cartridge provided with the developing device have been proposed, and various methods have been proposed for attaching the doctor blade to a developing case (developer housing case). (For example, Patent Documents 1 and 2).

  In recent years, tandem-type full-color image forming apparatuses have become widespread because of their high speed, and various types of tandem-type full-color image forming apparatuses have been proposed. In such an image forming apparatus, in order to increase the commercial value, there is an increasing demand for downsizing the image forming portion including the developing device. However, simply reducing the size of the developing device causes problems with durability and layout.

  In terms of durability, for example, if the diameter of the photosensitive drum is reduced, it is disadvantageous against discharge breakdown due to wear of the photosensitive drum film thickness, and the two-component developer accommodated by downsizing the developing device is small. When the capacity is reached, a small number of carriers are repeatedly agitated, which is disadvantageous against discharge breakdown due to the carrier film being scraped. In addition, if the gear is reduced in diameter, it is disadvantageous against wear, and other components generally have a problem that the strength becomes weaker when the gear becomes thinner and thinner.

  In terms of layout, for example, when the developing device is downsized, the proportion of tolerance with respect to the dimension increases, the degree of freedom in layout is lost, and design becomes difficult. For parts such as screws, bolts, and nuts, it is advantageous in terms of cost to use commercially available standard products. However, when standard parts are used, the size is limited to the standard and cannot be simply reduced. There is also a problem.

  In particular, when the diameter of the photosensitive drum is reduced, the ratio of the apparatus disposed around the photosensitive drum such as a developing device, a charging member, and a cleaning device occupies the outer peripheral surface of the photosensitive drum relatively increases, and exposure is increased. There is a problem that it is difficult to make a space through which the laser beam of the means passes.

  FIG. 7 is an explanatory diagram for explaining a problem when the diameter of the photosensitive drum is reduced. In the figure, reference numeral 100 denotes a photosensitive drum, reference numeral 110 denotes a charging roller, reference numeral 120 denotes a developing device, and L denotes a laser beam. The developing device 120 is a biaxial transport type developing device exemplified as a conventional developing device, and is supported by a developer containing case 121 for containing a developer composed of toner and a carrier, and a developer containing case 121. A developing roller 122 that carries developer on the outer peripheral surface and supplies toner to the electrostatic latent image on the photosensitive drum 100 for development; a doctor blade 123 that regulates the layer thickness of the developer carried by the developing roller 122; It has. The doctor blade 123 is screwed to the developer accommodating case 121 with a screw N so that the protruding end protrudes from the developer accommodating case 121 and is separated from the outer peripheral surface of the developing roller 122 by a predetermined gap.

  As is clear from FIG. 7, when the photosensitive drum 100 is downsized, the proportion of the developing device 120 and the charging roller 110 occupying the outer peripheral surface of the photosensitive drum 100 relatively increases. The interval is narrowed. It can be seen that the laser beam L emitted from the optical unit is blocked by the screw head of the screw N that holds the doctor blade 123 to the developer accommodating case 121 and does not reach the photosensitive drum 100. When the diameter of the photosensitive drum 100 is reduced in this way, it becomes difficult to secure a gap between the developing device 120 through which the laser beam L passes and the charging roller 110. Further, since the laser beam passes through the lens many times inside the optical unit and is irradiated after being reflected by the mirror, it is normal to expect an error of about 1 mm before reaching the photosensitive drum 100. Therefore, it is necessary to secure about several mm of this gap with a margin.

JP 2006-126664 A JP 2002-072671 A

  Accordingly, the present invention improves the method of attaching the developer regulating member to the development case in order to solve the above-mentioned conventional problems, and writes a latent electrostatic image on a latent image carrier even if the entire apparatus is downsized. It is an object of the present invention to provide a developing device, a process cartridge, an image forming apparatus, and a screwing method for a developer regulating member that can secure a light path.

  In order to solve the above-mentioned problems, the invention described in claim 1 is directed to a developer storage case for storing a developer, a shaft supported by the developer storage case, and a developer supported on the outer peripheral surface to carry a latent image. A developing roller that supplies toner to the electrostatic latent image on the body and develops it, and a developer regulating member that regulates the layer thickness of the developer carried by the developing roller, and the protruding end of the developer regulating member is In the developing device that is screwed to the developer accommodating case with a screw so as to be separated from the outer peripheral surface of the developing roller by a predetermined gap, the developer regulating member has an axial direction of the developing roller as a longitudinal direction. The flat plate portion has a plurality of screw holes threadedly engaged with the screw along the longitudinal direction, and the flat plate portion is located on the inside of the developer containing case. It is screwed so that the screw head of And butterflies.

  The invention according to claim 2 is characterized in that, in claim 1, the length of the screw foot of the screw is set to a length that does not protrude from the developer regulating member.

  A third aspect of the present invention is characterized in that, in the first or second aspect, the screw is made of a nonmagnetic material.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the hole through which the screw of the developer housing case passes is an oblong hole that is long in a direction perpendicular to the axis of the developing roller. And

  The invention described in claim 5 is the developer storage case according to claim 4, wherein the developer storage case is connected to the inside of the oval hole and is recessed in a shape similar to the oval hole to receive the screw head of the screw. And the shortest inner diameter of the counterbore part is substantially the same as the diameter of the screw head.

  The invention described in claim 6 is the screw according to claim 5, wherein the screw is a step screw provided with a step portion having a diameter smaller than the screw head diameter and larger than the screw foot diameter between the screw head and the screw foot. The diameter of the stepped portion of the stepped screw is characterized by a fitting tolerance with the short diameter of the oblong hole.

  A seventh aspect of the present invention is characterized in that, in any one of the first to sixth aspects, the developer containing case is provided with an insertion port for inserting a driver on an extension of the axis of the screw.

  The invention described in claim 8 is the developer storage case according to claim 7, wherein the developer containing case includes a stirring screw that stirs and conveys the developer to the developing roller, and the insertion port includes the axis of the stirring screw and the insertion path of the driver. And the straight line connecting the insertion hole and the screw hole of the developer accommodating case is arranged so as not to intersect.

  The invention described in claim 9 is the developer storage case according to claim 8, wherein the developer storage case is a two-axis transport type including a stirring screw and two transport paths thereof, and the insertion port is a transport path on the developer regulating member side. It is characterized by being provided only in.

  According to a tenth aspect of the present invention, in the seventh aspect, the developer storage case includes a stirring blade that stirs and supplies the developer to the developing roller, and the stirring blade is bent to avoid the driver when the driver is inserted. It is characterized by having flexibility.

  According to an eleventh aspect of the present invention, in any one of the seventh to tenth aspects, the insertion port is closed with a film-like seal from the inside or the outside of the developer accommodating case.

  A twelfth aspect of the present invention includes the developing device according to any one of the first to eleventh aspects.

  A thirteenth aspect of the invention includes the developing device according to any one of the first to eleventh aspects or the process cartridge according to the twelfth aspect.

  According to a fourteenth aspect of the present invention, the developer is accommodated by a developer regulating member that regulates the layer thickness of the developer by being separated by a predetermined gap from a developing roller that supplies toner to the electrostatic latent image for development. In the screwing method in which the developer containing case is screwed, the screw is fixed so that the screw head comes to the inside of the developer containing case.

  According to a fifteenth aspect of the present invention, in the fourteenth aspect, a screwdriver is inserted and screwed from an insertion port provided in the developer housing case.

  The invention described in claim 16 is characterized in that, in claim 15, the developer restricting member is screwed to the developer accommodating case, and then the insertion port is closed with a film-like seal.

  The present invention is as described above. According to the first aspect of the present invention, the developer storage case for storing the developer, the shaft supported by the developer storage case, and carrying the developer on the outer peripheral surface. A developing roller for supplying toner to the electrostatic latent image on the latent image carrier for development, and a developer regulating member for regulating the layer thickness of the developer carried by the developing roller. In the developing device in which the protruding end of the restricting member is screwed to the developer containing case with a screw so that the protruding end of the restricting member is separated from the outer peripheral surface of the developing roller by a predetermined gap, the developer restricting member is The flat plate portion has a rectangular shape with the axial direction as the longitudinal direction, the flat plate portion has a plurality of screw holes that are screwed with the screw along the longitudinal direction, and the flat plate portion is the developer containing case. Screwed so that the screw head of the screw comes inside Therefore, according to the second aspect of the present invention, the length of the screw foot of the screw is set to a length that does not protrude from the developer restricting member. The latent image carrier can be reduced in size without sacrificing the above, and a laser beam path for writing an electrostatic latent image on the latent image carrier can be secured.

  According to the third aspect of the present invention, since the screw is made of a nonmagnetic material in the first or second aspect, in addition to the above effects, there is no possibility that the screw is magnetized to adversely affect the conveyance of the developer.

  According to the fourth aspect of the present invention, in any one of the first to third aspects, the hole through which the screw of the developer accommodating case passes is an oblong hole that is long in the direction perpendicular to the axis of the developing roller. In addition to the above effect, the gap between the developer regulating member and the developing roller can be easily adjusted to a predetermined value by, for example, screwing a plate having the same thickness as the gap between the developing roller and the developer regulating member and screwing it. Can be screwed. In addition, the gap can be easily set to a predetermined value during readjustment such as maintenance.

  According to a fifth aspect of the present invention, in the fourth aspect, the developer accommodating case has a countersink portion that is recessed in a shape similar to the oblong hole and accommodates the screw head of the screw inside the oblong hole. Since the shortest inner diameter of the countersunk portion is substantially the same as the diameter of the screw head, in addition to the above effects, the screw head of the screw does not interfere with the developer conveyance, and the countersink portion It is possible to minimize wasteful developer that accumulates in the toner. Further, the counterbore part functions as a guide when the screw is attached to the screw hole, and can be easily screwed.

  According to the invention described in claim 6, in claim 5, the screw is a step screw in which a step portion having a diameter smaller than the screw head diameter and larger than the screw foot diameter is provided between the screw head and the screw foot. Since the diameter of the stepped portion of the stepped screw has a fitting tolerance with the short diameter of the oblong hole, in addition to the above effect, the stepped portion of the stepped screw having no thread groove on the outer peripheral surface The developer regulating member can be attached so as to have a predetermined gap without fine adjustment by simply fitting the portion and the oval hole.

  According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the developer containing case is provided with an insertion port for inserting a driver on an extension of the axis of the screw. The developer regulating member can be easily screwed from the inside of the developer housing case with a general-purpose tool such as a screwdriver. Further, the gap between the developer regulating member and the developing roller can be easily readjusted during readjustment such as maintenance.

  According to an eighth aspect of the present invention, in the seventh aspect, the developer storage case includes a stirring screw that stirs and conveys the developer to the developing roller, and the insertion port includes an axis of the stirring screw and a screwdriver screw. Since the straight line connecting the insertion port serving as the insertion path and the screw hole of the developer accommodating case is arranged not to intersect, the developer regulating member and the developing roller are attached after the stirring screw is attached to the developer accommodating case. It is also possible to finely adjust the gap, and it is not necessary to remove the stirring screw once at the time of readjustment such as maintenance, thereby improving workability.

  According to the ninth aspect of the present invention, in the eighth aspect, the developer accommodating case is a two-axis conveying type provided with two stirring screws and two conveying paths, and the insertion port is located on the developer regulating member side. Since it is provided only in the conveyance path, that is, in the developing device of the biaxial conveyance type, the driver insertion path when attaching the developer regulating member to the plane on which the two stirring screws exist is set to a predetermined angle or more. In this way, the driver has only one insertion port, so even in the biaxial transport type developing device, the work for closing the insertion port is only one place, and the work efficiency is improved.

  According to a tenth aspect of the present invention, in the seventh aspect, the developer storage case includes a stirring blade that stirs and supplies the developer to the developing roller, and the stirring blade avoids the driver when the driver is inserted. In addition to the above-described effect, the developer regulating member can be attached to the developer accommodating case after the agitating blade is attached to the developer accommodating case, so that workability is improved. Further, it is easy to finely adjust the gap between the developer regulating member and the developing roller, and it is not necessary to remove the stirring blade during readjustment such as maintenance.

  According to an eleventh aspect of the present invention, in the seventh to tenth aspects, the insertion port is closed with a film-like seal from the inside or the outside of the developer housing case. The insertion port can be closed only by the operation of sticking to the insertion port, and the work efficiency is improved. Moreover, if the adhesive of the seal is made to be able to be reattached, the work can be easily performed only by removing or sticking the seal in the case of readjustment such as maintenance.

  According to the twelfth aspect of the present invention, since the process cartridge includes the developing device according to any of the first to eleventh aspects, the above effect can be achieved in the process cartridge.

  According to the thirteenth aspect of the present invention, the image forming apparatus includes the developing device according to any one of the first to eleventh aspects or the process cartridge according to the twelfth aspect. Can be played.

  According to the fourteenth aspect of the present invention, the developer regulating member that regulates the layer thickness of the developer separated from the developing roller that supplies toner to the electrostatic latent image and develops it by a predetermined gap is provided with the developer. In the screwing method in which the developer containing case is screwed, the screw head is screwed inside the developer containing case so that the latent image carrier can be made small without sacrificing the degree of freedom of layout. Thus, a laser beam path for writing an electrostatic latent image on the latent image carrier can be secured.

  According to the fifteenth aspect of the present invention, in the fourteenth aspect, since a screwdriver is inserted and screwed from an insertion port provided in the developer housing case, in addition to the above effects, it is easy to use with a general-purpose tool such as a screwdriver. Further, the developer regulating member can be screwed from the inside of the developer containing case. Further, the gap between the developer regulating member and the developing roller can be easily readjusted during readjustment such as maintenance.

  According to the invention described in claim 16, in addition to the above effect, in addition to the above-described effect, the seal is formed by sealing the insertion port with a film-like seal after screwing the developer regulating member to the developer containing case. The insertion port can be closed only by the operation of sticking to the insertion port, and the work efficiency is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Image forming apparatus]
FIG. 1 is an explanatory diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. Reference numeral 1 in the figure denotes a four-tandem type intermediate transfer type color printer that forms a color image from toners of four colors of yellow, cyan, magenta, and black exemplified as an embodiment of the image forming apparatus of the present invention. The color printer 1 includes a device body 10 having a substantially casing shape, a new toner storage portion 2 that is disposed at the top of the device body 10 and stores the four colors of new toner, and a center of the device body 10. The image forming unit 3 for forming each single-color toner image from the four color toners, and the image forming unit 3 is disposed below the image forming unit 3, and each latent image carrier of the image forming unit 3 has an electrostatic latent image. An optical unit 4 for writing an image, a transfer unit 5 disposed above the image forming unit 3 and transferring the toner image formed by the image forming unit 2 to a recording material, and near one side end above the transfer unit 5 Placed A fixing unit 6 that fixes the toner image transferred by the transfer unit 5 to a recording material, a paper feeding unit 7 that is disposed at the lowermost part of the apparatus main body 10 and feeds recording paper as a recording material to the transfer unit 4; A paper discharge unit 8 is formed on the upper surface of the apparatus main body 10 and stacks recording sheets on which images are fixed by the fixing unit 6.

  The new toner storage unit 2 is a space for storing new toner, which is a new toner that is not used for development, and new toner bottles 2Y, 2C, and 2M that individually store yellow, cyan, magenta, and black toners. , 2K.

  The image forming unit 3 includes four process cartridges 3Y, 3C, 3D, which will be described later, centering on four photosensitive drums Y, C, M, and K as latent image carriers corresponding to yellow, cyan, magenta, and black toners. Consists mainly of 3M and 3K, and forms single-color toner images with process cartridges 3Y, 3C, 3M, and 3K from yellow, cyan, magenta, and black toners supplied from new toner bottles 2Y, 2C, 2M, and 2K. To do.

  The optical unit 4 has a laser light source (not shown) such as a semiconductor laser (LD) or a light emitting diode (LED), and the photosensitive drums Y, C, M, and K are irradiated with laser light from the laser light source to obtain a predetermined light source. The surfaces of the photosensitive drums Y, C, M, and K that are uniformly charged to polarities are exposed to form an electrostatic latent image.

  The transfer unit 5 includes an endless belt-like intermediate transfer belt 50 made of a semiconductive elastic resin as an intermediate transfer member, and four support rollers 51, 52, 53, 54 that support and stretch the intermediate transfer belt 50. And four primary transfer rollers 55Y, 55C, 55M, and 55K that face the four photosensitive drums Y, C, M, and K with the intermediate transfer belt 50 interposed therebetween, respectively. The support roller 51 is a drive roller connected to a drive means (not shown), and rotationally drives the intermediate transfer belt 50 in the direction of the arrow in the figure. A secondary transfer roller 56 is provided at a position facing the drive roller 51 and the intermediate transfer belt 50, and a cleaning unit 57 is provided at a position facing the support roller 52 and the intermediate transfer belt 50. ing.

Each of these primary transfer rollers 55Y, 55C, 55M, and 55K takes image deterioration due to gap discharge into consideration, from a directly facing position where the photosensitive drums Y, C, M, and K are in contact with the intermediate transfer belt 50 therebetween. Contact-type transfer bias (transfer voltage) applying means disposed at a position slightly shifted downstream in the transport direction of the intermediate transfer belt 50, connected to a bias power source (not shown), and connected to and separated from the intermediate transfer belt 50 by a contact / separation mechanism (not shown). The primary transfer nip is formed by contact from the inside of the intermediate transfer belt, and a primary transfer bias having a polarity opposite to that of the toner image is applied from the back surface (inner peripheral surface) of the intermediate transfer belt 50.
The transfer bias applying means may be a non-contact type using a transfer charger, but in the present embodiment, the primary transfer roller that generates less transfer dust is employed.

  The secondary transfer roller 56 is configured to be in pressure contact with the intermediate transfer belt 50 on the outer periphery of the driving roller 51 by an urging unit (not shown) to form a secondary transfer nip, and is connected to a bias power source (not shown). This is a contact-type transfer bias applying means for applying a secondary transfer bias having a polarity opposite to the above. Further, the drive roller 51 may be a transfer bias applying unit, and in this case, a transfer bias having the same polarity as the toner image to be transferred is applied.

  The cleaning unit 57 is a cleaning unit that collects transfer residual toner attached to the surface of the intermediate transfer belt 50 with a fur brush and a cleaning blade. The collected transfer residual toner is not shown in the cleaning unit 57 by a conveyance unit (not shown). It is transported to the waste toner tank and discarded.

  The fixing unit 6 includes a fixing roller 60 having a heater as a heat generating means, a pressure roller 61, and the like. The pressure roller 61 is urged and pressed against the fixing roller 60 by an urging means (not shown). A fixing nip is formed. Then, in this fixing nip, the recording material conveyed from the paper feeding unit 7 to be described later is subjected to heat from the fixing roller 60 and pressure from the pressure roller 61, whereby the unfixed image transferred to the recording material by the transfer unit 5 is determined. The fixed toner image is fixed on the recording material.

  The paper supply unit 7 includes a paper supply cassette 70 for storing and stocking a recording material (not limited to paper) of a predetermined size such as a copy paper, a resin sheet (such as an OHP sheet) and the like. A pickup roller 71 that is pressed against the recording material at a predetermined pressure and feeds the recording material one by one to the conveyance path based on a control signal of a control means (not shown), and a timing for conveying the recording material to the secondary transfer nip. A registration roller pair 72 to be adjusted is provided.

  The paper discharge unit 8 includes a paper discharge tray 80 formed on the upper surface of the apparatus main body 10, and a paper discharge roller pair 81 that discharges the recording material that has passed through the fixing unit 6 to the paper discharge tray 80 from the apparatus main body 10. The recording material discharged from the discharge roller pair 81 is accumulated on the discharge tray 80.

[Process cartridge]
Next, the process cartridge of the printer 1 will be described.
FIG. 2 is an explanatory diagram showing the structure of a process cartridge according to an embodiment of the present invention. As described above, the color printer 1 includes the four process cartridges 3Y, 3C, 3M, and 3K in the order of yellow, cyan, magenta, and black from the upstream side in the movement direction along the lower surface of the intermediate transfer belt 50 ( (See FIG. 1). Since these process cartridges 3Y, 3C, 3M, and 3K have substantially the same configuration, the process cartridge 3Y for yellow disposed at the most upstream will be described as an example.

  The process cartridge 3Y includes a lubricant applying means 30Y for applying a lubricant to the photosensitive drum Y from the upstream side in the rotation direction around the photosensitive drum Y as a latent image carrier, and the photosensitive member after the primary transfer. Cleaning means 31Y for cleaning transfer residual toner remaining on the drum Y, charging means 32Y for uniformly charging the outer peripheral surface of the photosensitive drum Y to a predetermined polarity, and an electrostatic latent image carried by the photosensitive drum Y Is mainly composed of a developing device 33Y that visualizes the image with yellow toner.

  The lubricant application means 30Y is housed in the housing case 30Ya, the solid lubricant 30Yb that is housed in the housing case 30Ya and is formed into a rectangular parallelepiped, and rotates to scrape the solid lubricant 30Yb to form the photosensitive drum Y. The brush roller 30Yc to be applied and a pressure spring 30Yd that presses the solid lubricant 30Yb against the brush roller 30Yc are mainly configured.

  The cleaning unit 31Y is in contact with the photosensitive drum Y and scrapes off the primary transfer residual toner that adheres to the outer peripheral surface of the photosensitive drum Y even after the primary transfer, cleans the cleaning blade 31Ya, its support member 31Yb, The blade pressing spring 31Yc, which is an urging means that presses the support member 31Yb to press the cleaning blade 31Ya against the photosensitive drum Y with a predetermined pressure, and the transfer residual toner scraped off by the cleaning blade 31Ya to a waste toner tank (not shown). And a toner conveying screw 31Yd for conveying.

  The lubricant applying unit 30Y may be provided in the cleaning unit 31Y together with the cleaning blade 31Ya. By doing so, the toner adhering to the brush by rubbing the photosensitive drum Y with the brush roller 30Yc can be easily collected by shaking off with the solid lubricant 30Yb or flicker.

  The charging unit 32Y is disposed in proximity to the photosensitive drum Y, and is disposed so as to contact the charging roller 32Ya as a charging member that uniformly charges the outer peripheral surface of the photosensitive drum Y to a predetermined polarity. The cleaning roller 32Yb removes the toner adhering to the charging roller 32Ya.

[Developer]
Next, the developing device 33Y will be described in detail with reference to FIG.
FIG. 3 is an explanatory diagram showing the configuration of the developing device according to the embodiment of the present invention.
The illustrated developing device 33Y is a biaxial transport type two-component developing type developing device exemplified as an embodiment of the developing device of the present invention, and contains a powdery two-component developer composed of toner and carrier. A developer storage case 33Ya that is supported by the developer storage case 33Ya, a developer roller 33Yb that is supported by the developer storage case 33Ya, is driven to rotate in the direction indicated by the arrow in FIG. Two agitating screws 33Yc and 33Yd that are supported by the case 33Ya and convey the developer to the developing roller 33Yb while agitating the developer, and a first developer conveying path 33Ye and a second developer conveying path that are conveying paths thereof 33Yf and a doctor blade 33Yg that is a developer regulating member that regulates the layer thickness of the developer carried by the developing roller.

  As shown in the figure, the developer accommodating case 33Ya has an opening for exposing the developing roller 33Yb, and serves as a conveying path for supplying the developer to the developing roller 33Yb. The first developer conveying path 33Ye And a second developer transport path 33Yf. An insertion port D for inserting a driver, which will be described later, is provided at the bottom of the second developer transport path 33Yf. The film-like seal S is stuck from the outside of the case and closed.

  The developing roller 33Yb is composed of a developing sleeve 34Y whose surface is processed so as to easily carry the developer, and a magnet roller 35Y as magnetic field generating means mounted inside the developing sleeve 34Y, and contains the developer. It is partially exposed from the opening of the case 33Ya and is arranged close to the photosensitive drum Y so as to be driven to rotate in the direction of the arrow in the figure. The magnet roller 35Y has magnets P1, P2, P3, P4, and P5 extending in the axial direction of the developing sleeve 34Y. The magnet roller 35Y is installed in a direction in which the magnet P3 and the magnet P4 generate a magnetic field having the same polarity. Matching magnets are installed in directions that generate magnetic fields of different polarities.

  The stirring screws 33Yc and 33Yd each have a rotation shaft and a screw surface, and are installed in the first developer transport path 33Ye and the second developer transport path 33Yf. Then, the developer roller 33Yb is rotated while rotating in the direction of the arrow in the drawing, charged with stirring, conveyed in the opposite direction, and circulated along the axial direction (horizontal direction) of the developing roller 33Yb. To supply.

  The doctor blade 33Yg is a blade plate that is a rectangular flat plate portion with the axial direction of the developing roller 33Yb as a longitudinal direction. The doctor blade 33Yg protrudes from the developer containing case 33Ya, and the protruding end thereof has a predetermined gap from the outer peripheral surface of the developing roller 33Yb. The developer accommodating case 33Ya is screwed with a screw n so as to be separated by G. The blade plate of the doctor blade 33Yg has a plurality of screw holes h1 along the longitudinal direction, and the screw holes h1 are formed with screw grooves that are screwed with the threads of the screw n. The screw n is screwed so that the screw head of the screw n comes inside the developer containing case 33Ya. The doctor blade 33Yg may be composed of a chevron plate that is bent to provide strength, rather than a blade plate made only of a flat plate portion. In that case, the folded portion is folded toward the developer containing case.

(Development operation)
Next, the operation of the developing device will be described with reference to FIG.
The developer is stirred by the stirring screws 33Yc and 33Yd, the toner is charged to a predetermined polarity, and the carrier is charged to the opposite polarity. Then, the charged yellow toner is pumped up by the magnetic force of the magnet roller 35Y of the developing roller 33Yb in the agent supply region, and is carried on the developing roller 33Yb (developing sleeve 34Y). Then, the developer layer thickness is regulated by the tip of the doctor blade 33Yg, and the developing roller 33Yb is rotated to be carried to a developing area close to the outer peripheral surface of the photosensitive drum Y. Therefore, the yellow toner carried on the developing roller 33Yb is electrostatically transferred to the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum Y, whereby the electrostatic latent image on the photosensitive drum Y is changed. It is visualized to become a yellow toner image. The developer remaining on the outer peripheral surface of the photosensitive drum Y after development is conveyed to the agent removal area by the further rotation of the developing roller 33Yb. The agent detachment region is a repulsive magnetic field region in which the magnets P3 and P4 of the magnet roller 35Y generate a repelling magnetic field, and the developer conveyed by this magnetic force is separated from the surface of the developing sleeve 34Y. In this agent detachment area, the developer separated from the surface of the developing sleeve 34Y falls to the second developer conveyance path 33Yf and is used for re-development.

(Process cartridge operation)
Next, the operation of the process cartridge will be described with reference to FIG.
First, the outer peripheral surface of the photosensitive drum Y is uniformly charged to a predetermined polarity by the charging roller 32Ya, and a laser beam is generated based on the image information by the optical unit 4 in the downstream area of the charging roller 32Ya in the rotation direction of the photosensitive drum Y. An electrostatic latent image is formed by decreasing the surface potential of the uniformly charged photoreceptor drum Y by irradiating L, and reducing only the irradiated portion. Then, as described above, the developing device 33Y converts the electrostatic latent image into a toner image and develops it. This toner image moves to the primary transfer nip with the rotation of the photosensitive drum Y, where a primary transfer bias is applied from the primary transfer roller 55Y and transferred to the intermediate transfer belt 50. Thereafter, the lubricant is applied to the surface of the photosensitive drum Y by the lubricant applying means 30Y. The primary transfer residual toner that adheres to the outer peripheral surface of the photosensitive drum Y even after the primary transfer is cleaned by the cleaning unit 31Y, and is prepared for another image formation.

(Image forming operation)
Next, the image forming operation of the color printer 1 will be described with reference to FIG.
First, as described above, a yellow single-color toner image is formed on the photosensitive drum Y in the process cartridge 3Y. Subsequently, the photosensitive drum Y is rotated to the primary transfer nip, where a primary transfer bias having a polarity (for example, plus) opposite to the polarity of the toner is applied by the primary transfer roller 55Y, and electrostatic attraction is applied. A yellow monochrome toner image is transferred to the intermediate transfer belt 50. Similarly, in the other process cartridges 3C, 3M, and 3K, a single color toner image is formed, and primary transfer is performed in the order of yellow, cyan, and magenta in accordance with the rotation timing of the intermediate transfer belt 50. Is performed and superimposed on the intermediate transfer belt 50 to form a full-color toner image.

  On the other hand, the recording material conveyed from the paper feeding unit 7 is fed to the secondary transfer nip after the transfer timing is adjusted by the registration roller pair 72. Therefore, a secondary transfer bias is applied by the secondary transfer roller 56, and the full-color toner image on the intermediate transfer belt 50 is transferred onto the recording material by electrostatic attraction. Next, the recording material carrying the unfixed toner image on the surface is sent to the fixing nip of the fixing unit 6 and fixed by applying heat and pressure. As described above, after the image is fixed on the recording material, the image is discharged and stacked on the paper discharge unit 8. Further, the transfer residual toner that adheres to the surface of the intermediate transfer belt 50 after the secondary transfer after the transfer is removed by the cleaning unit 57 and is prepared for another image forming operation. The transfer residual toner removed by the cleaning unit 57 is carried to a waste toner tank (not shown) and discarded.

[Screw and screw hole]
Next, screws and screw holes according to embodiments of the present invention will be described with reference to FIGS. FIG. 4 is a front view showing an outline of a screw exemplified as an embodiment of the screw of the present invention, and FIG. 5 is a developer containing case as seen from the inside of the developer containing case in the direction of arrow A in FIG. It is A arrow line view which shows the through-hole of this.
As shown in FIG. 4, the screw n illustrated as an embodiment of the screw of the present invention is made of a non-magnetic material, and includes a screw head n1, a screw foot n2, and a step portion n3 provided therebetween. It is a stepped screw. As shown in the figure, the step portion n3 has a diameter r3 smaller than the diameter r1 of the screw head n1 and larger than the outer diameter r2 of the screw foot n2, and no thread is formed on the outer peripheral surface. The length t2 of the screw foot n2 is set to a length that does not protrude from the doctor blade 33Yg. That is, t2 ≦ T.

  The hole (h2) through which the screw n of the developer containing case 33Ya shown in FIG. 5 passes is provided in the doctor blade 33Yg and is provided in a position corresponding to the plurality of screw holes h1 screwed with the screw n. One of the holes on the case 33Ya side is illustrated, and as shown in the figure, it is an oblong hole having a long diameter r4 and a short diameter r5 that is long in the direction perpendicular to the axis of the developing roller 33Yb. Further, the developer containing case 33Ya is provided with a countersink portion h3 (shaded portion in FIG. 5) which is recessed in a shape similar to the oblong hole h2 on the inner wall surface of the oblong hole h2. The countersink part h3 is a space for accommodating the screw head n1 of the screw n, and the thickness t1 of the screw head n1 and the depth d of the countersink part h3 are set to be substantially the same. Further, the shortest inner diameter r6 of the counterbore part h3 is substantially the same diameter slightly smaller than the diameter r1 of the screw head n1. For this reason, the screw head n1 of the screw n does not hinder the developer conveyance, and wasteful developer accumulated in the countersunk portion h3 can be minimized. Further, the counterbore part h3 functions as a guide when the screw n is attached to the oblong hole h2, and can be easily screwed.

  Further, the step n3 of the screw n has a fitting tolerance relationship with the diameter r3 of the step r3 of the oblong hole h2, and therefore, the step n3 and the oblong hole h2 in which no thread groove is cut on the outer peripheral surface. And the developer regulating member can be attached so as to have a predetermined gap G without fine adjustment.

(Insertion position)
Next, the position of the insertion slot will be described with reference to FIG.
The insertion port D is an opening for inserting a screwdriver for tightening the screw n, and is provided on the extension of the axis of the screw n, and the driver insertion path indicated by the rotating shafts of the stirring screws 33Yc and 33Yd and the dashed arrow A, that is, The straight line connecting the insertion opening D and the screw holes h1 and h2 is arranged so as not to intersect. That is, the driver insertion path is set to be at a predetermined angle or more with respect to the plane where the two stirring screws 33Yc and 33Yd exist, and the driver insertion path is connected to the first developer transport path 33Ye and the second developer transport path 33Ye. Since the driver has only one insertion port so as not to pass through the two conveyance paths of the developer conveyance path 33Yf, the work for closing the insertion port is completed at one place, and the work efficiency is improved.

Next, the screwing method according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is an explanatory diagram for explaining a screwing method according to the embodiment of the present invention.
As shown in FIG. 6, when the doctor blade 33Yg is screwed to the developer accommodating case 33Ya, basically, the stirring screw 33Yd is attached without being attached. This is because the stirring screw 33Yd is obstructive and difficult to work. However, as described above, since the position of the insertion port D is set so that the rotation shaft of the stirring screw 33Yd and the driver insertion path do not intersect with each other, after the stirring screw 33Yd is mounted on the developer containing case 33Ya. But it can be screwed. Therefore, the gap between the doctor blade 33Yg and the developing roller 33Yb can be easily readjusted during readjustment such as maintenance.
At this time, as shown in the figure, when a plate P having the same thickness as the gap G is inserted between the doctor blade 33Yg and the developing roller 33Yb and is bitten, a screwdriver is inserted from the insertion port D and screwed. Can be set easily and reliably.
When the gap is screwed to a predetermined value G, a film-like seal S is attached from the outside of the developer accommodating case 33Ya to close the insertion opening D as shown in FIG. As described above, since the insertion port can be closed only by an extremely simple operation of sticking the seal, the work efficiency is improved.

  As described above, according to the development measure and the process cartridge according to the present embodiment, the path of the laser beam from the optical unit can be secured even if the photosensitive drum is miniaturized, and thus there is a degree of freedom in layout. The developing device and the process cartridge can be reduced in size. In the above description, the screw according to the embodiment of the present invention has been described by taking a step screw as an example, but it may be a commercially available general screw such as a flat screw, a round screw, a pan-bottom screw, Even in that case, since the screw head does not protrude outside from the developer accommodating case and the developer regulating member, it is needless to say that the path of the laser beam can be secured. Further, although a screw-like stirring screw has been described as an example of the developer agitating and conveying means, an agitating blade having sufficient flexibility that can be bent to avoid the driver when the driver is inserted (for example, Mylar) It is good also as a stirring blade made from. By doing so, the doctor blade can be attached to the developer accommodating case with the stirring blades attached to the developer accommodating case, and the workability is improved. Further, it is easy to finely adjust the gap between the doctor blade and the developing roller, and it is not necessary to remove the stirring blade during readjustment such as maintenance.

Further, the image forming apparatus according to the embodiment of the present invention has been described by taking a four-tandem type intermediate transfer system as an example. However, the image forming apparatus is not necessarily limited to this, and for example, a four-tandem type direct transfer system. Or a monochrome image forming apparatus. In short, a developer containing case, a developing roller, and a developer regulating member are provided, and the developer containing case is screwed with a screw so that the protruding end of the developer regulating member is separated from the outer peripheral surface of the developing roller by a predetermined gap. Any image forming apparatus that is stopped may be used.
In addition, the detailed configuration of the new toner storage unit, the optical unit, the transfer unit, the fixing unit, the paper feeding unit, the paper discharge unit, etc. is merely an example, and the configuration of other known devices and means, etc. Can be adopted. Even in such a case, it is clear that the same effect can be obtained with respect to the above-mentioned problem.
In addition, the shape, structure, etc. of each structural member shown by drawing show a preferable example to the last.

1 is a configuration explanatory view showing an image forming apparatus according to a first embodiment of the present invention. 1 is a configuration explanatory view showing a process cartridge according to an embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating a configuration of a developing device according to an embodiment of the present invention. It is a front view showing a schematic structure of a screw illustrated as an embodiment of a screw of the present invention. FIG. 4 is an A arrow view showing a through hole of the developer accommodating case when the inside of the developer accommodating case is viewed in the direction of arrow A in FIG. It is explanatory drawing explaining the screwing method which concerns on embodiment of this invention. FIG. 6 is an explanatory diagram for explaining a problem when the diameter of the photosensitive drum is reduced.

Explanation of symbols

1 Color printer (image forming device)
3Y, 3C, 3M, 3K Process cartridge 33Y Developer 33Ya Developer housing case h2 Oval hole (hole through which screw passes)
h3 Countersink 33Yb Developing roller (developer carrier)
33Yc, 33Yd Stirring screw (stirring conveyance means)
33Ye First developer transport path (transport path)
33Yf Second developer transport path (transport path)
33Yg Doctor blade (Developer regulating member)
h1 Screw hole n Screw n1 Screw head n2 Screw foot n3 Step D Insertion slot S Seal

Claims (16)

A developer accommodating case for accommodating the developer, and a developing roller that is pivotally supported by the developer accommodating case, carries the developer on the outer peripheral surface, and supplies toner to the electrostatic latent image on the latent image bearing member for development. And a developer regulating member that regulates the layer thickness of the developer carried by the developing roller,
In the developing device screwed to the developer containing case so that the protruding end of the developer regulating member is separated from the outer peripheral surface of the developing roller by a predetermined gap,
The developer regulating member has a rectangular flat plate portion whose longitudinal direction is the axial direction of the developing roller, and the flat plate portion has a plurality of screw holes that are screwed with the screw along the longitudinal direction. The developing device is characterized in that the flat plate portion is screwed so that the screw head of the screw comes inside the developer accommodating case.   The developing device according to claim 1, wherein a length of a screw foot of the screw is set to a length that does not protrude from the developer regulating member.   The developing device according to claim 1, wherein the screw is made of a nonmagnetic material.   4. The developing device according to claim 1, wherein the hole through which the screw of the developer storage case passes is an oblong hole that is long in a direction perpendicular to the axis of the developing roller. 5.   The developer storage case is connected to the inside of the oval hole, and has a countersink portion that is recessed in a shape similar to the oval hole and receives the screw head of the screw. The developing device according to claim 4, wherein the inner diameter is substantially the same as the diameter of the screw head. The screw is a step screw in which a step portion having a diameter smaller than the screw head diameter and larger than the screw foot diameter is provided between the screw head and the screw foot.
6. The developing device according to claim 5, wherein the diameter of the stepped portion of the stepped screw has a fitting tolerance with the short diameter of the oblong hole.   7. The developing device according to claim 1, wherein the developer housing case has an insertion port for inserting a driver on an extension of an axis of the screw. The developer storage case includes a stirring screw that stirs and conveys the developer to the developing roller,
The insertion port is arranged so that an axis of the stirring screw and a straight line connecting an insertion port serving as a driver insertion path and a screw hole of the developer containing case do not intersect with each other. Item 8. The developing device according to Item 7.   The developer storage case is a biaxial transport type including the stirring screw and two transport paths thereof, and the insertion port is provided only in the transport path on the developer regulating member side. The developing device according to claim 8. The developer storage case includes a stirring blade that stirs and supplies the developer to the developing roller,
The developing device according to claim 7, wherein the stirring blade has flexibility to bend to avoid the driver when the driver is inserted.   The developing device according to claim 7, wherein the insertion port is closed with a film-like seal from the inside or the outside of the developer containing case.   12. A process cartridge comprising the developing device according to claim 1.   An image forming apparatus comprising the developing device according to claim 1 or the process cartridge according to claim 12. A screw that screws a developer regulating member that regulates the layer thickness of the developer with a predetermined gap away from a developing roller that supplies toner to the electrostatic latent image and develops it to a developer housing case that houses the developer In stopping method,
A method of screwing a developer regulating member, wherein the screw is fixed so that a screw head comes inside the developer containing case.   The method of screwing a developer regulating member according to claim 14, wherein a screwdriver is inserted and screwed from an insertion port provided in the developer containing case.   16. The method for screwing a developer regulating member according to claim 15, wherein the insertion port is closed with a film-like seal after the developer regulating member is screwed to the developer housing case.

Images