JP2008164911A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-life developing device 16 capable of preventing a toner supply part 58 from being excessively filled with toner, causing neither deterioration of toner nor sorting of particle size and further coping with miniaturization. <P>SOLUTION: The developing device 16 has a photoreceptor drum 11, a developing roller 53, a supply roller 54, a regulating member 55 and a stirring member 56. A first partition 61 is provided to partition the developing device 16 so as to form the toner supply part 58 in which the developing roller 53, the supply roller 54 and the regulating member 55 are arranged, and a toner storage part 59 in which the stirring member 56 is arranged, and a second partition 62 is provided nearer to the toner storage part 59 side than the first partition 61 so as to be opposed to the first partition 61. The first partition 61 has one or a plurality of apertures 63 at a position where it is opposed to the second partition 62, and a path part 64 where the toner moves is formed by the first partition 61 and the second partition 62. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, and a facsimile machine, and an image forming apparatus including the developing device.

  In general, in an electrophotographic image forming apparatus (such as a copying machine or a printer), an electrostatic latent image is formed on an image carrier, and toner is supplied to the image carrier, and a toner image developed with the toner is displayed. An image is formed by transferring and fixing it onto a sheet or the like. Here, the developing device plays a role of supplying toner to the image carrier. Specifically, in general, the developing device supplies toner to a predetermined potential by a regulating member or the like that is pressed against the developing roller to form a thin toner layer on the developing roller provided to face the image carrier. The charged toner is supplied toward the electrostatic latent image on the image carrier, and the electrostatic latent image is developed.

  In general, a developing device includes a one-component developing method and a two-component developing method. The one-component development method is a method using a developer mainly composed of toner, and the two-component development method is a method using a developer mainly composed of toner and a carrier (magnetic material). Development devices based on the one-component development system have been conventionally disposable because they are generally lower in cost and smaller than those based on the two-component development method. However, in recent years, development devices have been developed from the viewpoint of increasing environmental awareness and effective use of resources. Regardless of the system, a long-life developing device has been demanded.

  However, in particular, in a one-component developing type developing device, the image forming apparatus is generally deteriorated in image quality as the developing device is used for a long time due to toner deterioration or particle size selection. There are technical difficulties.

  When the toner is deteriorated, the fluidity of the toner is lowered and the charging of the toner becomes unstable, and the toner is excessively charged or insufficiently charged, thereby causing fogging, density reduction, unevenness, toner scattering, and the like. Further, in the particle size selection in which the toner remaining in the developing device is increased in size and accumulated, the toner remaining for a long time is pressurized by a regulating member in the developing device, and the external additive is buried in the toner. In many cases, it has already deteriorated due to peeling or peeling. When such deteriorated toner is used for development, the toner may be deposited on a white background portion of paper or the like that should not be printed (so-called fogging), the density may be reduced, and the toner may be scattered. The quality of the recorded image will deteriorate.

Therefore, the invention described in Patent Document 1 has been proposed mainly for the problem of toner particle size selection. Japanese Patent Application Laid-Open No. 2004-133620 discloses a partition member that separates a toner storage unit that stores toner therein, a toner supply unit that transports toner to an image carrier, and a partition member in a direction from the toner storage unit to the toner supply unit. In a developing device provided with an opening / closing member that opens only, a toner feeding member that guides toner from the toner container to the toner supply unit, and a toner supply member that conveys toner to the toner carrier, the upper end of the opening / closing member is fixed and the lower end Describes a developing device provided with a protrusion protruding toward the toner supply section (see Patent Document 1: Claim 1, FIG. 4, etc.). With this configuration, the toner having a large particle size is prevented from returning to the toner supply unit, and a large amount of toner is supplied to the toner supply unit and the toner supply unit is prevented from being clogged with toner. An excessive load is not applied (see Patent Document 1: Paragraph 0014).
JP2003-255687

  Here, in the invention described in Patent Document 1, an open / close member as a backflow prevention valve for preventing the return of the large particle size toner is provided in the toner storage portion so that the toner does not move from the toner storage portion toward the toner supply portion. I have to. It is also possible to prevent an excessive burden on the toner supply member.

  However, the toner supply unit is always full of toner, and the pressure in the toner supply unit is always kept high. When image formation, particularly low density printing, is performed with such an excessively filled toner, toner deterioration proceeds due to the regulating member, etc., and the pressure of the toner supply unit is high, so the toner deterioration is accelerated. There is a problem of going forward.

  Further, when the gap between the newly supplied toner and the degree of toner deterioration existing in the toner containing portion becomes large, the detailed cause is unknown, but the toner is poorly charged and is opposite to the polarity at which the deteriorated toner is to be charged. In some cases, the polarity is charged. This is presumably because the toner with advanced deterioration becomes unstable in charging and may be charged to the opposite polarity. Such charging to the reverse polarity causes fogging and causes deterioration in image quality.

  When the toner deteriorates, the fluidity of the toner is deteriorated, charging becomes insufficient or excessively charged, and the charging of the toner becomes unstable. Problems such as a decrease in image density, fogging, toner scattering, unevenness, etc. Occurs, and the image quality of the formed image decreases. That is, the invention of Patent Document 1 has a problem that the deterioration of the toner may cause the image quality to deteriorate at an early stage after the use of the image forming apparatus, and the request for a long life cannot be satisfied. .

  In particular, in recent years, there has been a demand for downsizing of the developing device, and in the downsized developing device, the amount of toner accommodated is reduced. Therefore, when the invention described in Patent Document 1 is downsized, there is a problem that the ratio of deteriorated toner in the toner supply unit is relatively high, and deteriorated toner is easily accumulated in the toner supply unit. Therefore, the invention of Patent Document 1 cannot cope with the downsizing of the developing device.

  In summary, the developing device described in Patent Document 1 cannot cope with the problem of toner deterioration because there is no mention of toner deterioration even though it can cope with the problem of particle size selection. In addition, as described above, it is impossible to meet the demand for longer life and size reduction of the developing device.

  The present invention has been made in view of the above-described problems of the prior art. In the developing device, the toner supply unit is not excessively filled with toner, and there is no toner deterioration or particle size selection, and further miniaturization is achieved. An object of the present invention is to provide a developing device having a corresponding long life. It is another object of the present invention to provide an image forming apparatus having a long life by stabilizing the quality of an image formed over a long period of time by using this developing device.

  According to the first aspect of the present invention, the toner is accommodated in the apparatus, and the toner is supplied to the image carrier to develop the electrostatic latent image formed on the image carrier, and is arranged to face the image carrier. A developing roller, a supply roller that supplies toner to the developing roller, a regulating member that contacts the developing roller and regulates the thickness of the toner layer formed on the developing roller, and stirs the contained toner A developing device having a stirring member for forming a toner supply portion in which the developing roller, the supply roller, and the regulating member are disposed, and a toner storage portion in which the stirring member is disposed. And a second partition is provided on the toner container side of the first partition so as to face the first partition. The first partition faces the second partition. To do Has one or more openings in, by the first partition and the second partition, it was decided to passage of toner is moved is formed.

  According to a second aspect of the present invention, in the developing device according to the first aspect, the first partition is opposed to an inner wall portion of the frame in the developing device close to the developing roller in the frame of the developing device. The first partition is provided to extend to a position closer to the opposed inner wall portion than the second partition.

  According to a third aspect of the present invention, in the developing device according to the first or second aspect, an end opening having a predetermined length is provided at an end in the longitudinal direction of the first partition, and the second partition is provided. Is provided so as not to face the end opening.

  According to a fourth aspect of the present invention, in the developing device according to the third aspect, the end opening is provided with a valve so that the toner of the toner supply section moves only from the toner supply section side toward the toner storage section side. Was decided to be provided.

  According to a fifth aspect of the present invention, the toner is accommodated in the apparatus, the toner is supplied to the image carrier to develop the electrostatic latent image formed on the image carrier, and the toner is opposed to the image carrier. A developing roller, a supply roller that supplies toner to the developing roller, a regulating member that contacts the developing roller and regulates the thickness of the toner layer formed on the developing roller, and the contained toner A developing member having an agitating member for agitating the toner, a toner supply portion in which the developing roller, the supply roller, and the regulating member are disposed in the developing device, and a toner storage portion in which the agitating member is disposed. In order to form the first partition, a second partition is provided on the toner supply unit side of the first partition so as to face the first partition, and the first partition and the second partition are formed. By Was the passage of toner is moved is formed.

  According to a sixth aspect of the present invention, in the developing device according to the fourth aspect, the first partition is opposed to an inner wall portion of the frame body adjacent to the supply roller in the developing device in the frame body of the developing device. The second partition is provided in a direction from the opposed inner wall portion toward the first partition.

  According to a seventh aspect of the present invention, in a developing unit that supports a plurality of developing devices and has a rotating frame for rotationally driving the plurality of developing devices, some or all of the plurality of developing devices are claimed. Item 7. The developing device according to any one of Items 1 to 6, wherein the developing roller of each developing device faces the image carrier when the support rotates.

  According to an eighth aspect of the present invention, an image forming apparatus includes the developing device according to any one of the first to sixth aspects or the developing unit according to the seventh aspect.

  According to the first aspect of the present invention, the toner is replenished by moving from the toner storage portion to the toner supply portion through the passage portion formed by the first partition and the second partition. Only the amount of toner that has been applied is gradually supplied to the toner supply unit, and the toner supply unit is not excessively filled with toner. Accordingly, the pressure in the toner supply unit can be kept constant and low, and toner deterioration can be minimized. Further, since the inside of the developing device is separated by the first partition and the second partition, it is possible to make the particle size selection difficult to occur.

  Thus, since it is difficult for toner deterioration and particle size selection to occur, it is possible to provide a long-life developing device that is free from problems such as fogging, density reduction, and toner scattering and does not deteriorate image quality over a long period of time. Further, since the deteriorated toner is not accumulated in the toner supply unit in the developing device even if the developing device is downsized, it is possible to provide a developing device that can cope with downsizing.

  Invention of Claim 2 is one of the concrete structures for forming a channel | path part, In addition to the effect of the invention of Claim 1, the structure of a 1st partition and a 2nd partition is a simple thing. In addition, it is possible to easily provide a developing device free from toner deterioration. This is one of the preferred embodiments.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, due to the configuration, the toner flow may deteriorate at the end in the longitudinal direction of the developing device, and toner accumulation may occur. However, since the end opening is provided at the longitudinal end of the first partition corresponding to the longitudinal end of the developing device, the toner can be returned from the toner supply unit to the toner storage unit. As a result, it is possible to prevent toner from being accumulated at the end portion in the longitudinal direction of the developing device in the toner supply unit, and it is possible to prevent an increase in pressure and toner deterioration in the toner supply unit.

  According to the invention described in claim 4, in addition to the effect of the invention described in claim 3, since the valve member is provided at the end opening, the toner that has just been replenished to the developing device and has not been sufficiently stirred is supplied to the toner supply portion. Intrusion can be prevented, and the degree of toner deterioration in the developing device can be made uniform.

  The invention according to claim 5 is different from the invention according to claim 1 in the positions where the first partition and the second partition are provided, and has the same effect as the invention according to claim 1.

  Invention of Claim 6 is one of the concrete structures for forming a channel | path part, In addition to the effect of the invention of Claim 5, the structure of a 1st partition and a 2nd partition can be simplified. Therefore, it is possible to easily provide a developing device free from toner deterioration.

  According to the seventh aspect of the invention, since the developing unit is a so-called rotary type developing unit, the toner is returned from the passage portion to the toner supply portion by rotating the developing unit. Can do. As a result, the degree of toner deterioration in the toner storage unit and the toner supply unit is made uniform, the residual toner in the toner storage unit does not remain, and a developing device free from image defects such as fogging can be provided. .

  According to the eighth aspect of the present invention, since the image forming apparatus includes the developing device or the developing unit according to any one of the first to seventh aspects, an image forming apparatus having stable image quality over a long period of time and a long service life is provided. Can do. Further, since the developing device is compatible with miniaturization, the image forming apparatus can be miniaturized regardless of color or monochrome.

  Embodiments of the present invention will be described below with reference to the drawings. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

  First, the outline of the image forming apparatus 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view for explaining a schematic configuration of an image forming apparatus 1 according to the first embodiment of the present invention. The present invention can be applied to any tandem type or rotary type developing device, but in the present embodiment, an image forming apparatus 1 including a rotary type developing unit 2 will be described.

  The image forming apparatus 1 according to the present embodiment includes an image forming unit 10, a replenishing unit 20, an intermediate transfer unit 24, a paper feeding unit 30, a paper transport unit 35, a secondary transfer unit 45, a fixing device 47, and the like. .

  As shown in FIG. 1, the image forming unit 10 includes a rotary developing unit 2, a photosensitive drum 11, a charging roller 12, a drum cleaning device 13, a laser unit 14, and the like.

  The photosensitive drum 11 has an electrostatic latent image formed on its surface as an image carrier, and is driven to rotate approximately at the center of the image forming apparatus 1 (the direction of rotation is indicated by an arrow). The rotation shaft (not shown) is provided so as to extend perpendicular to the paper surface of FIG. The photosensitive drum 11 is formed to have a photosensitive layer such as amorphous silicon or an OPC photosensitive member.

  The charging roller 12 is provided on the photosensitive drum 11. The charging roller 12 is in contact with the photosensitive drum 11 to uniformly charge the surface of the photosensitive drum 11, and is rotatably supported. Note that a cleaner 12 a for cleaning adhering matter adhering to the charging roller 12 is provided above the charging roller 12.

  The drum cleaning device 13 is provided on the right side of the photosensitive drum 11 in FIG. 1 and is for cleaning toner and deposits remaining on the surface of the photosensitive drum 11.

  The rotary developing unit 2 is for developing the electrostatic latent image formed on the photosensitive drum 11 with toner of each color, and is provided adjacent to the left side of the photosensitive drum 11 in FIG. . The rotary developing unit 2 includes a rotating frame 15 and four developing devices 16B (black), 16Y (yellow), 16C (cyan), and 16M (magenta) supported by the rotating frame 15. It is rotated by a drive mechanism that does not include a motor or gear. Accordingly, the rotary developing unit 2 has a cylindrical shape that is rotatable around the rotation shaft 15a. The rotary shaft 15 a of the rotary developing unit 2 passes through the center of the rotary frame 15, and the axial direction thereof is parallel to the axial direction of the rotary shaft of the photosensitive drum 11.

  As shown in FIG. 1, the rotating frame 15 has four sections that are equally divided into four in the circumferential direction by partition frames 15 b that extend radially from the center of the rotating shaft 15 a. In each section, developing devices 16B, 16Y, 16C, and 16M corresponding to four toner colors of black, yellow, cyan, and magenta are arranged. The developing devices 16B, 16Y, 16C, and 16M have the same configuration. is there. When the rotary developing unit 2 rotates, the developing rollers 53 of the developing devices 16B, 16Y, 16C, and 16M face the photosensitive drum 11 with a predetermined gap. The detailed structure of each developing device 16B, 16Y, 16C, 16M will be described later.

  The laser unit 14 is for scanning and exposing the photosensitive drum 11 based on image information from an external computer or the like, and is provided above the rotary developing unit 2. Data for causing the laser unit 14 to output the laser light 14L is created by the data processing unit 17 that receives image information. Then, the laser light 14L is emitted from the laser unit 14. A reflection mirror 18 is provided on the optical path of the laser beam 14L, and the laser beam 14L is irradiated onto the surface of the photosensitive drum 11 by the reflection mirror 18 (the laser beam 14L is shown by a two-dot chain line). The laser unit 14 includes a laser light source, a polygon mirror, a polygon mirror driving motor, and the like as an internal configuration (not shown).

  The replenishing unit 20 includes a toner storage container 21 and a toner replenishing device 22. The toner storage containers 21 are provided above the photosensitive drum 11 and the intermediate transfer belt 25, and four toner storage containers 21 are arranged side by side in the direction perpendicular to the paper surface of FIG. Each toner storage container 21 is a portion that stores toner to be replenished to each developing device 16B, 16Y, 16C, 16M of the rotary developing unit 2. That is, each toner storage container 21 stores toner of any one color of black, yellow, cyan, and magenta. In FIG. 1, the toner container 21 is invisible except for one toner container 21.

  The toner replenishing device 22 is disposed above the photosensitive drum 11 in a space between the laser unit 14 and the toner storage container 21, and is configured to be movable up and down. Four toner replenishing devices are provided corresponding to the respective colors. . Each toner replenishing device 22 is connected to the corresponding toner storage container 21 by a pipe, a hose or the like, and supplies the toner of each color stored in the toner storage container 21 to the corresponding developing device 16B, 16Y, 16C, 16M.

  Specifically, the toner replenishing device 22 has an insertion portion 22a with a thin tip, and when it moves downward, the tip is inserted into the developing devices 16B, 16Y, 16C, and 16M to supply toner. . Further, when the replenishment is completed, it moves upward and the rotary developing unit 2 becomes rotatable. In FIG. 1, the parts other than one toner supply device 22 are invisible. Further, the moving direction of the toner replenishing device 22 is shown by a broken line.

  The intermediate transfer unit 24 includes an intermediate transfer belt 25 to which toner images of respective colors formed on the photosensitive drum 11 are sequentially transferred, a driving roller 26 for tensioning and rotating the intermediate transfer belt 25, a tension roller 27, A primary transfer roller 28 adjacent to the photosensitive drum 11 via the intermediate transfer belt 25, a driven roller 28a provided between the drive roller 26 and the primary transfer roller in the vicinity of the primary transfer roller 28, and intermediate transfer A belt cleaning device 29 for cleaning the belt 25 is configured. The intermediate transfer belt 25 stretched around each roller rotates and passes through the nip between the photosensitive drum 11 and the primary transfer roller 28, and the toner images of the respective colors are superimposed and primarily transferred, and the superimposed toner images. Is later transferred to the paper P by the secondary transfer unit 45.

  The paper feed unit 30 includes a paper feed cassette 31, a manual feed tray 32, and the like. A paper feed cassette 31 having a placement plate 31 a on which the paper P is placed is provided at the bottom of the image forming apparatus 1. In addition, the paper feed unit 30 prevents the double feed to the right side of the pickup roller 33 and the pickup roller 33 to the right of the pickup cassette 31 in order to send out the paper P on the loading plate 31 a one by one to the paper conveyance path. A roller pair 34 is provided. Further, a manual feed tray 32 is provided on the right side surface of the apparatus so that paper can be separately fed. The manual feed tray 32 is also provided with a pickup roller 33 for sending the paper P one by one to the paper transport path.

  The paper transport unit 35 is for transporting the paper P in the image forming apparatus 1. The sheet conveying section 35 is a sheet for discharging the image-formed sheet P from the sheet feeding section 30 to a secondary transfer roller 46 described later, and from the secondary transfer roller 46 through the fixing device 47. From the second conveyance path 37 that reaches the discharge port 42, the reverse conveyance path 38 that is provided so as to connect the middle of the first conveyance path 36 to the middle of the second conveyance path 37 on the downstream side of the fixing device 47 in the sheet conveyance direction. Composed. Note that the paper transport direction is indicated by arrows.

  A curved portion 39 is provided in the first conveyance path 36 in order to reverse the conveyance direction of the paper P sent out from the paper feed cassette 31. In addition, at the upper part of the curved portion 39, the conveyance path from the manual feed tray 32 joins. In front of the secondary transfer roller 46, a registration roller pair 40 for controlling the conveyance timing of the paper P is disposed. A plurality of pairs of conveyance rollers 41 are provided in the conveyance path in which these elements are provided, and a guide plate (not shown) for guiding the paper P is also provided as appropriate.

The second transport path 37 is provided with a plurality of transport roller pairs 41. A guide plate (not shown) for guiding the paper P is also provided as appropriate. A paper discharge port 42 is provided at the end of the second transport path 37.
And a discharge tray 43 for receiving the discharged paper P is provided.

  The reverse conveyance path 38 is a conveyance path for duplex printing. The reverse conveyance path 38 is provided so as to join the upstream side of the registration roller pair 40 in the sheet conveyance direction from the branching claw 44 located in the middle of the second conveyance path 37 and downstream of the fixing device 47 in the sheet conveyance direction. The reverse conveyance path 38 is provided so as to pass above the paper feed cassette 31. The reverse conveyance path 38 is also provided with a plurality of conveyance roller pairs 41, and a guide plate (not shown) for guiding the paper P is also provided as appropriate.

  The secondary transfer unit 45 includes a secondary transfer roller 46 and a driving roller 26. The secondary transfer roller 46 is for transferring the toner image transferred to the intermediate transfer belt 25 onto the sheet P conveyed so as to be sandwiched between the secondary transfer roller 46 and the intermediate transfer belt 25. Therefore, the secondary transfer roller 46 is supported so as to be rotatable and in contact with and away from the intermediate transfer belt 25 so as to form a nip via the drive roller 26 and the intermediate transfer belt 25. Further, a voltage is applied to the secondary transfer roller 46 so that the toner is transferred onto the paper P at a predetermined timing by a voltage applying means (not shown).

  The fixing device 47 is for melting and fixing the toner transferred onto the paper P, and is provided in the middle of the second transport path 37 and below the rotary developing unit 2. The fixing device 47 includes a heating roller 48 that incorporates a heater and a pressure roller 49 that presses the heating roller 48. The toner is heated and pressurized and fixed on the paper P.

  Next, an image forming operation will be briefly described. The image forming apparatus 1 executes an image forming operation based on the input image data as follows.

  First, the photosensitive drum 11 is charged by the charging roller 12. The laser unit 14 scans and exposes the surface of the photosensitive drum 11 in accordance with data from the data processing unit 17 to which image data is input, and the electrostatic latent image is formed on the photosensitive drum 11. Is formed. Next, the rotary developing unit 2 is rotated, and one of the corresponding color developing devices 16 faces the photosensitive drum 11. In this state, the electrostatic latent image on the photosensitive drum 11 is developed by supplying the corresponding color toner. The developed toner image is transferred to the intermediate transfer belt 25. The above operation is sequentially repeated for each color, and a full-color toner image is formed on the intermediate transfer belt 25 (if full color, the intermediate transfer belt 25 rotates four times). For example, when a black single-color image is formed, the above operation may be performed once. The toner remaining on the photosensitive drum 11 after the transfer is cleaned by the drum cleaning device 13.

  On the other hand, in the paper feed unit 30, one sheet P is taken out from the paper feed cassette 31 or the manual feed tray 32 by the pickup roller 33 and conveyed to the registration roller pair 40. Thereafter, the sheet P is conveyed from the registration roller pair 40 to the toner image on the intermediate transfer belt 25 in time, and is guided to the secondary transfer unit 45. A predetermined voltage is applied to the secondary transfer roller 46 while being in contact with the intermediate transfer belt 25, and the toner image on the intermediate transfer belt 25 is transferred to the paper P. The sheet P is guided to the fixing device 47 through the second conveyance path 37, and the toner image is fixed on the sheet P by the fixing device 47. In the case of single-sided printing, the paper is sequentially discharged from the paper discharge port 42 via the branching claw 44, and the paper P is received by the discharge tray 43.

  On the other hand, in the case of duplex printing, the paper P that has passed through the fixing device 47 is switched back in the second conveyance path 37 downstream of the branching claw 44 in the paper conveyance direction, and the reverse conveyance path 38 is guided by the branching claw 44. To be introduced. Thereafter, the paper P that is turned upside down is returned to the upstream side of the pair of registration rollers 40 in the first transport path 36 again. Then, the toner image is transferred from the secondary transfer roller 46 in time with the back side of the paper P. After that, it is the same as above.

  Next, the developing devices 16B, 16Y, 16C, and 16M according to the first embodiment of the present invention supported by the rotary developing unit 2 will be described with reference to FIG. Here, since the constructions of the developing devices 16B, 16Y, 16C, and 16M are the same, the following explanation and the reference numerals of the drawings are omitted unless otherwise indicated. The description will be made in a unified manner with the device 16. Therefore, the following description applies in common to the developing devices 16B, 16Y, 16C, and 16M unless otherwise specified.

  FIG. 2 is a cross-sectional view showing a schematic configuration of the developing device 16 according to the first embodiment of the present invention. 2 shows a state where the developing roller 53 is stationary at a position where the developing roller 53 faces the photosensitive drum 11.

  The developing device 16 mainly includes a frame 51, a partition member 52, a developing roller 53, a supply roller 54, a regulating member 55, a stirring member 56, a toner supply port 57, and the like.

  The frame 51 constitutes the outer shell of the developing device 16. Then, the toner is accommodated in the inside and other members are provided.

  The partition member 52 is formed of, for example, a metal or resin plate member, and includes a first partition 61 and a second partition 62. The first partition 61 is provided in the frame body 51 of the developing device 16 from the inner wall portion 51a of the frame body adjacent to the developing roller 53 and the supply roller 54 in the developing device 16 to the opposed inner wall portion 51b (see FIG. 2 from bottom to top). On the other hand, the second partition 62 is provided on the toner container 59 side of the first partition 61 so as to face the first partition 61. In other words, the second partition 62 is attached to the first partition 61 so as to face along a direction parallel to the longitudinal direction of the first partition 61.

  Of the partition members 52, the interior of the developing device 16 is separated into the toner supply unit 58 and the toner storage unit 59 mainly by the first partition 61. The toner supply unit 58 is a part that supplies toner to the photosensitive drum 11, and includes a developing roller 53, a supply roller 54, a regulating member 55, and the like. A stirring member 56 and a toner supply port 57 are disposed in the toner storage portion 59.

  As described above, the first partition 61 separates the inside of the developing device 16 into the toner supply unit 58 and the toner storage unit 59, but has one or a plurality of openings 63 at a position facing the second partition 62. Through the opening 63, the toner can be moved from the toner containing portion 59 to the toner supply portion 58, and the toner is replenished. That is, the opposing part of the 1st partition 61 and the 2nd partition 62 is the channel | path part 64 for a toner to move. A more detailed configuration of the first partition 61 and the second partition 62 will be described later.

  As shown in FIG. 2, a part of the developing roller 53 is exposed from the frame 51, and is arranged opposite to the photosensitive drum 11 (a part is shown by a broken line in FIG. 2) with a certain gap. It is rotatably supported. Then, the rotary developing unit 2 rotates, and the developing roller 53 on which a thin layer of toner of each color is formed is opposed to the photosensitive drum 11 and supplies toner to the photosensitive drum 11. A seal member 53a is provided between the developing roller 53 and the frame 51 to prevent toner leakage.

  The supply roller 54 is provided between the developing roller 53 and the partition member 52 so as to be in contact with the developing roller 53 in order to supply and convey toner to the developing roller 53. The supply roller 54 is rotatable and supported so that the axis of the supply roller 54 and the axis of the developing roller 53 are parallel. The supply roller 54 is rotated in the same direction as the developing roller 53 (clockwise in FIG. 2) by a drive mechanism (not shown) including a gear, a motor, and the like. The supply roller 54 supplies toner to the developing roller 53 at the contact portion between the developing roller 53 and the supply roller 54 in the upper contact portion in FIG. 2 (near the regulating member 55), and the lower contact portion in FIG. The portion (in the vicinity of the inner wall portion 51a) functions to scrape off toner that has not been used for development.

  The regulating member 55 is formed in a film shape or a blade shape with resin, metal or the like. The regulating member 55 is supported so that one plane abuts along the axial direction of the developing roller 53. As described above, the regulating member 55 is for forming a thin layer of toner on the developing roller 53, and further has a function of charging the toner by friction and a predetermined voltage applying means (not shown). .

  The agitating member 56 is for agitating the toner in the toner accommodating portion 59, and the supply roller 54, the developing roller 53 and the axis line are provided substantially parallel and in parallel, and the agitating member 56a, the agitating blade 56b, and the like. Composed. The shaft portion 56a is provided so as to be bridged in the toner storage portion 59 and is rotatably supported. As shown in FIG. 2, the shaft portion 56a has a substantially T-shaped cross section, and its longitudinal end portion is connected to a gear and a motor (not shown) and is rotated. For example, a film-like or sheet-like stirring blade 56b made of a resin such as PET is attached to the shaft member 56a, and the stirring member 56 is configured.

  The toner replenishing port 57 is for receiving toner replenishment from the replenishing portion 20, and is provided in the toner accommodating portion 59 on the frame portion 51 b facing the frame portion 51 a close to the stirring member 56. (Upper position in FIG. 2). The front end portion 22 a of the toner supply device 22 is inserted into the toner supply port 57, and toner is supplied to the developing device 16. Therefore, the toner supply port 57 is provided corresponding to the toner supply device 22.

  Next, a more detailed configuration of the partition member 52 in the developing device 16 according to the first embodiment of the present invention will be described based on FIG. FIG. 3A is a perspective view of the first partition 61 according to the first embodiment of the present invention as viewed from the toner supply unit 58 side, and FIG. 3B is a diagram illustrating how the second partition 62 is attached to the first partition 61. FIG. 6 is a perspective view seen from the direction of the toner storage portion 59 for explanation. (C) is a perspective view showing a state in which the second partition 62 is attached to the first partition 61.

  As shown in FIG. 3A, the first partition 61 is formed long in the left-right direction in FIG. That is, the first partition 61 is formed to extend along the axial direction of the developing roller 53 and the stirring member 56 in the developing device 16 (see FIG. 2). A plurality of openings 63 are provided in parallel in the longitudinal direction of the first partition 61 slightly above the center of the first partition 61 in the vertical direction. By providing the opening 63, toner is supplied from the toner storage unit 59 to the toner supply unit 58.

  Further, the first partition 61 has a curved portion 65 from the approximate center in the vertical direction to the lower end. This is because the first partition 61 is provided from the inner wall portion 51a of the frame adjacent to the developing roller 53 and the supply roller 54 toward the inner wall portion 51b facing the supply roller 54 so as to cover the supply roller 54 (FIG. 2). A plurality of locking claws 66 for fixing the position of the first partition 61 are provided at the lower end portion of the first partition 61 so as to be inserted into locking portions (not shown) provided on the inner wall portion 51a. The first partition 61 is firmly fixed by the locking claws.

  Then, as shown in FIGS. 3B and 3C, the second partition 62 is attached to the first partition 61 (the attachment direction is shown by a two-dot chain line). In the present embodiment, the length of the second partition 62 in the longitudinal direction is the same as that of the first partition 61. Here, the 2nd partition 62 is formed so that it may have two side wall parts 62a by bend | folding one plate-shaped member at the both ends in a longitudinal direction. Further, the side wall 62a is formed so as to coincide with the shape of the curved portion 65 of the first partition 61 when attached.

  By attaching the second partition 62 to the first partition 61, the first partition 61 and the second partition 62 face each other, and a pocket-shaped toner passage portion 64 is formed (see FIG. 2). The first partition 61 extends to a position closer to the inner wall portion 52b than the second partition 62. That is, even if the second partition 62 is attached, the first partition 61 protrudes longer in the upper part in the vertical direction with respect to the longitudinal direction of the first partition 61 (up and down direction in FIG. 3).

  Here, with reference to FIG. 2, a specific embodiment of the developing device 16 will be described, and the actual movement of the toner will be described. It should be noted that the present invention is not limited to this embodiment.

  As an example of the developing device 16, an elastic roller having a JIS-A hardness of 45 degrees and a surface roughness Ra of 1.0 μm is used for the developing roller 53. The supply roller 54 is adjusted using a urethane sponge roller so that the nip width with the developing roller 53 is 3 mm. The regulating member 55 is made of SUS having a thickness of 0.08 mm, and the regulating pressure that contacts the developing roller 53 is set to 25 N / m. As the sealing member, a conductive high molecular weight PE film is used, and is backed up with a urethane sponge so as to uniformly contact the developing roller 53. Further, a PET film having a thickness of 40 μm is used for the stirring blade 56 b of the stirring member 56.

  On the other hand, in the present embodiment, SUS having a thickness of 0.5 mm is used for the first partition 61 and the second partition 62 as the partition member 52, but may be appropriately changed according to the size of the developing device 16. It is possible. Here, the width of the gap between the first partition 61 and the second partition 62 facing each other is 1 to 8 mm, more preferably about 2 to 4 mm in the developing device 16 of the present embodiment. Furthermore, the 1st partition 61 is extended and formed in the inner wall part 51b of a frame rather than the 2nd partition 62, and it is 1-10 mm upwards in FIG. 2, More preferably, it is about 6-8 mm higher. Is formed. This is because toner flows into the passage portion 64, which is desirable in terms of replenishment and movement of the toner supply portion 58 and the toner storage portion 59 described later.

  In the developing device 16 formed in this way, as shown in FIG. 2, when the agitating member 56 rotates, the toner is agitated and splashed up in the toner accommodating portion 59 (so that the toner accommodating portion 59 is separated from the hopper portion). Sometimes called). Then, the splashed toner enters the passage portion 64. Since the height of the first partition 61 is higher than that of the first partition 61, toner accumulates up to the height of the second partition 62. That is, toner accumulates at the opposing portions of the first partition 61 and the second partition 62. The height of toner accumulation in the passage portion 64 is shown as a line L1.

  The toner that has entered the passage portion 64 is conveyed to the toner supply portion 58 via the supply roller 54. However, since the width of the gap between the first partition 61 and the second partition 62 of the passage portion 64 is about 4 mm, the toner does not flow into the toner supply portion 58 at once, and is matched to the amount of consumed toner. The toner is gradually supplied to the toner supply unit 58 by the weight of the toner. As a result, toner is not supplied more than necessary, and the toner supply unit 58 is not excessively filled with toner. Accordingly, the pressure in the toner supply unit 58 does not become so high as to cause toner deterioration, and is kept substantially constant (a guideline for the height of the toner in the toner supply unit 58 is shown as a line L2). Thereby, even if the low density output is continued, the toner does not deteriorate.

  That is, since the toner supply unit 58 and the toner storage unit 59 are separated by the partition member 52, the toner particle size selection can be suppressed, and the toner deterioration can be suppressed as described above. The developing device 16 or the image forming apparatus 1 has a long life without density reduction and toner scattering. Further, even if the developing device 16 is downsized, no particular adverse effects occur, and it is possible to meet the demand for downsizing of the developing device 16.

  Further, the developing device 16 in the present embodiment is supported by the rotary developing unit 2. As the rotary developing unit 2 rotates, part of the toner in the toner supply unit 58 returns to the toner storage unit 59 through the passage unit 64. As a result, although the amount of toner is changed little by little, it becomes possible to reduce the difference in the degree of toner deterioration between the toner supply unit 58 and the toner storage unit 59. When the difference in the degree of toner deterioration becomes large (when toner deterioration of the toner supply unit 59 progresses too much), the deteriorated toner may be charged to a polarity opposite to the polarity to be charged, resulting in a decrease in image quality. cause. However, in this embodiment, the difference in the degree of deterioration can be reduced, and the image quality is maintained.

  Even in the case of an image forming apparatus using a tandem developing device, if the developing device 16 in the present embodiment is used, the particle size selection and the toner deterioration hardly occur in the first place, so that the long-life developing device 16 and the image forming device 1 are used. It becomes.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4A is a perspective view seen from the direction of the toner container 59 in order to explain the attachment of the second partition 62 to the first partition 61 according to the second embodiment of the present invention. FIG. 6B is a perspective view showing a state in which the second partition 62 is attached to the first partition 61. Here, the second embodiment is different from the first embodiment in the way of providing the second partition 62.

  Since the basic configuration of the second embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 3, the configuration common to the above embodiment is described in the drawings. The description is omitted. That is, the points other than the differences to be described may be the same as those in the first embodiment.

  As shown in FIGS. 4A and 4B, the partition member 52 of the second embodiment is provided with an end opening 67 having a predetermined length at an end of the first partition 61 in the longitudinal direction. As shown in FIG. 4A, the second partition 62 is provided so as not to face the end opening 67. That is, the passage portion 64 is not formed at the longitudinal end portion of the first partition 61.

  Further, the end opening 67 is provided with a valve 68 so that the toner of the toner supply unit 58 moves only from the toner supply unit 58 side toward the toner storage unit 59 side. Specifically, from the toner container 59 side, a sheet-like member made of resin such as PET is used as a valve 68 so as to cover the end opening 67 along one side of the rectangular end opening 67. Fix by gluing.

  As a result, since the toner is returned from the toner supply unit 58 to the toner storage unit 59 at the end portion in the longitudinal direction of the developing device 16, an increase in pressure in the toner supply unit 58 can be avoided and the difference in the degree of deterioration of the toner can be avoided. It can be prevented from becoming large. Further, the valve 68 can prevent the toner immediately after replenishment into the developing device 16 from directly moving to the toner supply part 58, particularly when the end opening is located directly below the toner replenishment port 57.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view of the developing device 16 according to the third embodiment of the present invention. Here, the third embodiment is different from the first embodiment in the way of providing the partition member 52.

  Since the basic configuration of the third embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 3, the configuration common to the above embodiment is described in the drawings. The description is omitted. That is, the points other than the differences to be described may be the same as those in the first embodiment.

  As shown in FIG. 5, the first partition 61 and the second partition 62 are provided as the partition member 52 in the same manner as the other embodiments, but the first partition is closer to the toner supply unit 58 than the first partition 61. The difference is that a second partition 62 is provided so as to face 61. Thus, even if the partition member 52 is provided, the passage portion 64 through which the toner moves is formed.

  Specifically, the first partition 61 is provided from the inner wall portion 51a of the frame adjacent to the developing roller 52 toward the opposing inner wall portion 51b (in the direction from bottom to top in FIG. 5), and the second partition 61 62 is provided in the direction from the opposing inner wall portion 51b toward the first partition 61 (the direction from the top to the bottom in FIG. 5). Even if the partition member 52 is configured in this manner, the same effect as in the first embodiment is obtained.

  In this manner, as shown in the first embodiment, the toner is accommodated in the apparatus, and the photosensitive drum 11 is developed to develop the electrostatic latent image formed on the photosensitive drum 11 as the image carrier. A developing roller 53 that supplies toner and is arranged to face the photosensitive drum 11, a supply roller 54 that supplies toner to the developing roller 53, and a toner layer formed on the developing roller 53 in contact with the developing roller 53 In the developing device 16 having a regulating member 55 for regulating the thickness and an agitating member 56 for agitating the stored toner, toner in which the developing roller 53, the supply roller 54, and the regulating member 55 are arranged in the developing device 16. A first partition 61 is provided to form the supply unit 58 and the toner storage unit 59 in which the stirring member 56 is disposed. The first partition 61 is closer to the toner storage unit 59 than the first partition 61. A second partition 62 is provided so as to face the first partition 61, and the first partition 61 has one or a plurality of openings 63 at a position facing the second partition 62, and the first partition 61 and the second partition 62 If the passage portion 64 where the toner moves is formed, only the amount of toner consumed in the toner supply portion 58 is gradually replenished to the toner supply portion 58, and the toner is supplied by the toner supply portion 58. It will not be overfilled. Therefore, the pressure in the toner supply unit 58 can be kept constant and low, and toner deterioration can be minimized. Further, since the inside of the developing device 16 is separated by the first partition 61 and the second partition 62, the particle size selection can be hardly caused. As described above, since it is difficult for toner deterioration and particle size selection to occur, it is possible to provide a long-life developing device 16 that is free from defects such as fogging, density reduction, and toner scattering and does not deteriorate image quality over a long period of time. Further, even if the developing device 16 is downsized, the deteriorated toner is not accumulated in the toner supply unit 58 in the developing device 16, and therefore the developing device 16 that meets the demand for downsizing can be provided.

  Further, the first partition 61 is provided in the frame body 51 of the developing device 16 from the inner wall portion 51a of the frame body 51 adjacent to the developing roller 53 in the developing device 16 toward the inner wall portion 51b facing the first partition 61. If the partition 61 is provided to extend to a position closer to the opposed inner wall portion 51b than the second partition 62, the configuration of the first partition 61 and the second partition 62 can be simplified, and the toner deteriorates. It is possible to easily provide the developing device 16 without such as.

  As shown in the second embodiment, an end opening 67 having a predetermined length is provided at an end of the first partition 61 in the longitudinal direction so that the second partition 62 does not face the end opening 67. If provided, the toner flow may deteriorate at the longitudinal end portion of the developing device 16 due to the configuration, and toner accumulation may occur. However, the first partition corresponding to the longitudinal end portion of the developing device 16 may occur. Since the end opening 67 is provided at the end in the longitudinal direction of the toner 61, the toner can be returned from the toner supply unit 58 to the toner storage unit 59. As a result, it is possible to prevent toner from being accumulated at the end portion of the developing device 16 in the toner supply unit 58 in the longitudinal direction, and it is possible to prevent an increase in pressure at the toner supply unit 58 and toner deterioration.

  Further, if a valve 68 is provided at the end opening 67 so that the toner of the toner supply unit 58 moves only from the toner supply unit 58 side to the toner storage unit 59 side, it is sufficient that the developing device 16 has just been replenished. Therefore, it is possible to prevent the toner that has not been agitated from entering the toner supply unit 58 and to further uniform the degree of deterioration of the toner in the developing device 16.

  Further, as shown in the third embodiment, the toner is accommodated in the apparatus, and the toner is supplied to the photosensitive drum 11 for developing the electrostatic latent image formed on the photosensitive drum 11 as the image carrier. The developing roller 53 disposed opposite to the photosensitive drum 11, the supply roller 54 for supplying toner to the developing roller 53, and the thickness of the toner layer formed on the developing roller 53 in contact with the developing roller 53. In the developing device 16 having a regulating member 55 for regulating and an agitating member 56 for stirring the contained toner, a toner supply unit in which the developing roller 53, the supply roller 54, and the regulating member 55 are arranged in the developing device 16. 58 and a toner container 59 provided with a stirring member 56 are provided with a first partition 61, and the first partition 61 is closer to the toner supply unit 58 than the first partition 61. Even if the first partition 61 and the second partition 62 form a passage portion 64 through which the toner moves, the developing device 16 shown in the first embodiment is provided. Has the same effect.

  The first partition 61 is provided in the frame 51 of the developing device 16 from the inner wall 51a of the frame 51 adjacent to the developing roller 53 and the supply roller 54 in the developing device 16 toward the facing inner wall 51b. If the second partition 62 is provided in the direction from the opposed inner wall portion 51b toward the first partition 61, the configuration of the first partition 61 and the second partition 62 can be simplified, and toner deterioration, etc. It is possible to easily provide the developing device 16 without any problem.

  In the developing unit that supports the plurality of developing devices 16 and has a rotating frame for rotationally driving the plurality of developing devices 16, some or all of the plurality of developing devices 16 are the developing devices 16 according to the present invention. If the developing roller 53 of each developing device 16 is opposed to the image carrier by rotating the support, the developing unit rotates because the developing unit is a so-called rotary type developing unit. Thus, the toner can be returned from the passage portion 64 to the toner supply portion 58 from the toner storage portion 59. As a result, the degree of toner deterioration in the toner storage unit 59 and the toner supply unit 58 is made uniform, the residual of the deteriorated toner in the toner storage unit 59 is eliminated, and the developing device 16 free from image defects such as fog is provided. can do.

  Further, if the image forming apparatus 1 includes the developing device 16 or the developing unit, the image forming apparatus 1 having a stable image quality and a long life can be provided over a long period of time. Further, since the developing device 16 is compatible with miniaturization, the image forming apparatus 1 can be miniaturized regardless of color or monochrome.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in a developing device used in an image forming apparatus and an image forming apparatus provided with the developing device.

1 is a schematic cross-sectional view for explaining a schematic configuration of an image forming apparatus according to a first embodiment of the present invention. 1 is a cross-sectional view illustrating a schematic configuration of a developing device according to a first embodiment of the present invention. (A) is the perspective view which looked at the 1st partition concerning the 1st embodiment of the present invention from the toner supply part side, (b) is a toner storage in order to explain attachment of the 2nd partition to the 1st partition. It is the perspective view seen from the part direction. (C) is a perspective view which shows the state which attached the 2nd partition to the 1st partition. (A) is the perspective view seen from the toner accommodating part direction, in order to demonstrate attachment of the 2nd partition to the 1st partition which concerns on the 2nd Embodiment of this invention. (B) is a perspective view which shows the state which attached the 2nd partition to the 1st partition. These are sectional drawings of the developing device concerning a 3rd embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Rotary developing unit 16, 16B, 16Y, 16C, 16M Developing apparatus 51a, 51b Inner wall part (frame body 51)
52 Partition member 53 Developing roller 54 Supply roller 55 Restriction member 56 Stirring member 58 Toner supply unit 59 Toner storage unit 61 First partition (partition member 52)
62 Second partition (partition member 52)
64 passage 67 end opening 68 valve

Claims (8)

A developing roller which accommodates toner in the apparatus and supplies the toner to the image carrier in order to develop an electrostatic latent image formed on the image carrier and is disposed opposite to the image carrier; Development including a supply roller that supplies toner to the roller, a regulating member that is in contact with the developing roller and regulates the thickness of the toner layer formed on the developing roller, and a stirring member that stirs the stored toner In the device
A first partition is provided in the developing device to form a toner supply portion in which the developing roller, the supply roller, and the regulating member are disposed, and a toner storage portion in which the stirring member is disposed. A second partition is provided on the toner storage portion side of the first partition so as to face the first partition;
The first partition has one or more openings at a position facing the second partition,
A developing device according to claim 1, wherein the first partition and the second partition form a passage portion through which toner moves.   In the frame of the developing device, the first partition is provided from the inner wall portion of the frame adjacent to the developing roller in the developing device toward the opposing inner wall portion, and the first partition is more 2. The developing device according to claim 1, wherein the developing device extends to a position closer to the opposed inner wall portion than the second partition. An end opening with a predetermined length is provided at an end in the longitudinal direction of the first partition,
The developing device according to claim 1, wherein the second partition is provided so as not to face the end opening.   4. The developing device according to claim 3, wherein the end opening is provided with a valve so that the toner of the toner supply unit moves only from the toner supply unit side toward the toner storage unit side. A developing roller which accommodates toner in the apparatus and supplies the toner to the image carrier in order to develop an electrostatic latent image formed on the image carrier and is disposed opposite to the image carrier; A supply roller for supplying toner to the roller; a regulating member for regulating a layer thickness of a toner layer formed on the developing roller in contact with the developing roller; and an agitating member for agitating the stored toner In the developing device,
A first partition is provided in the developing device to form a toner supply portion in which the developing roller, the supply roller, and the regulating member are disposed, and a toner storage portion in which the stirring member is disposed. A second partition is provided on the toner supply section side of the first partition so as to face the first partition;
A developing device according to claim 1, wherein the first partition and the second partition form a passage portion through which toner moves.   In the frame of the developing device, the first partition is provided from an inner wall portion of the developing device close to the supply roller to an opposing inner wall portion, and the second partition is the facing inner wall portion. 6. The developing device according to claim 5, wherein the developing device is provided in a direction toward the first partition. In a developing unit that supports a plurality of developing devices and has a rotating frame for rotationally driving the plurality of developing devices,
7. The developing device according to claim 1, wherein a part or all of the plurality of developing devices is the developing device according to claim 1, and the developing roller of each developing device is attached to the image carrier when the support rotates. A developing unit characterized by being opposed to each other.   An image forming apparatus comprising the developing device according to claim 1 or the developing unit according to claim 7.

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