JP2017026926A - Method of assembling developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a change in shape of an SB gap in a developing device.SOLUTION: A developing device, which is used in an image forming apparatus, comprises a developer container that stores developer and a strength member that provides strength to the developing device. A method of assembling the developing device includes: a first step of pressing the developer container in contact with a butting member, to deform the developer container; and a second step of attaching the strength member providing strength to the developing device to the developer container, while the developer container is deformed through the first step.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an image forming apparatus using toner. For example, the present invention relates to an image forming apparatus applied to an image forming apparatus such as a copying machine and a laser beam printer using an electrophotographic system or an electrostatic recording system.

  Conventionally, in an image forming apparatus such as an electrophotographic copying machine, an electrostatic latent image formed on the surface of a photoreceptor is developed as a toner image by a developing device, transferred to a recording medium such as paper, and fixed and recorded by a fixing unit. A method of obtaining an image is used.

  In general, a developing device has a developing sleeve carrying a developer provided with a certain gap (hereinafter referred to as SD gap) with respect to a photosensitive drum. If the SD gap is wide, the developability deteriorates, and if the SD gap is narrow, the developer overflows. If the gap uniformity in the front, middle, and back is broken, the image density difference increases. Therefore, a pair of spacer rollers are arranged at both ends in the longitudinal direction of the developing sleeve, and the outer periphery of the spacer rollers abuts against the abutting members provided at both ends of the photosensitive drum, whereby the developing sleeve and the photosensitive drum are A configuration that guarantees the gap has been proposed.

  In recent years, there has been a demand for higher speed and higher image quality of copiers and printers. Correspondingly, the first developing sleeve located upstream of the image forming process and the first located downstream are aimed at stabilizing the image. A developing device having two developing sleeves is put into practical use. By providing two developing sleeves, the developing area between the developing sleeve and the photosensitive drum is widened so that high speed and high image quality can be accommodated. A developing device in which two developing sleeves each provided with a pair of spacer rollers at both ends of the developing sleeve are already put into practical use (Patent Document 1).

  Here, by providing two developing sleeves, the following problems occur. That is, in the developing device having the two developing sleeves, the spacer rollers for assuring the SD gap are grounded at four positions on the surface of the photosensitive drum or the abutting member. Generally, in order to obtain a stable surface contact, it is fundamental to abut three points. With the abutment of four points as described above, one point of the spacer roller is in a floating state. Therefore, in the positioning of the developing device and the photosensitive drum, a play is provided in the radial direction to allow a bus line deviation generated between the developing sleeve and the photosensitive drum to absorb the influence of the alignment error between the two sleeves. (Patent Document 2).

JP 2002-351111 A JP 2011-257745 A

  In the above-described conventional technology, the developing device is in a state in which distortion is included due to the force received during assembly, and is fixed by the strength member in a state including the distortion. Then, since the four spacer rollers are abutted against the positioning portion of the developing device provided in the dedicated jig, the developing device is deformed to the position where the spacer roller abuts on the jig, and the distortion is corrected.

  Therefore, on the jig, the SB gap between the developing sleeve and the blade is adjusted in a state including distortion. On the other hand, since the distortion of the developing device is absorbed by the positioning play provided on the photosensitive drum side when the developing device is installed in the main body, the four spacer rollers are abutted while the developing device is distorted. It will be. As described above, since the distortion corrected on the jig is not corrected in the main body, the SB gap is shifted between the jig and the main body by the distortion of the developing device.

  That is, on the jig, the developing device is twisted in a state where the strength member is attached, and this twist is returned when the developing device is mounted on the image forming apparatus. For this reason, the shape of the developing device is different between the jig and the image forming apparatus, and a value such as an SB gap may be different.

  Accordingly, an object of the present invention is to provide a developing device assembling method capable of suppressing changes in the SB gap and the like when the developing device is mounted on an image forming apparatus.

  A typical configuration of the present invention is a developing device used in an image forming apparatus, and a method for assembling a developing device having a developing container for storing a developer and a strength member for imparting strength to the developing device. A first step of deforming the developing container by abutting and pressing the developing container against an abutting member, and giving strength to the developing device in a state where the developing container is deformed by the first step And a second step of attaching a strength member to the developing container.

  In the assembling method of the developing device of the present invention, a strength member that gives strength to the developing device is attached to the developing container in a state where the developing container is abutted against and pressed against the abutting member to deform the developing container. By attaching a strength member with the developing container deformed, the developing device is fixed in the deformed state, and the developing device assembled on the jig can be used in the image forming apparatus to change the shape of the developing device such as the SB gap. Can be suppressed.

1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. It is a perspective view which shows the structure of the process unit which concerns on embodiment of this invention. 1 is a perspective view showing a state in which a developing device according to an embodiment of the present invention is mounted on a process unit. FIG. 3 is a perspective view showing a configuration of a mechanism for moving a developing device of the process unit according to the embodiment of the present invention. FIG. 2 is a cross-sectional view showing a developing device and its periphery when the developing device is stored in a process unit according to an embodiment of the present invention. 1 is a perspective view of a developing device according to an embodiment of the present invention. 1 is a perspective view of a photosensitive drum and its periphery according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a relationship between a developing sleeve and a photosensitive drum when the developing device according to the embodiment of the present invention is pressurized. It is the figure which showed the assembly procedure of the conventional developing device. FIG. 3 is a view of a developing sleeve and a photosensitive drum as viewed from the developing device side, and shows a bus line deviation. It is the figure which showed the assembly and adjustment process in this embodiment of a developing device. FIG. 6 is a view showing the periphery of a photosensitive drum and a developing device of an image forming apparatus according to another embodiment of the present invention.

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

<First Embodiment>
Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

(Overall configuration of image forming apparatus)
The overall configuration of the image forming apparatus of this embodiment will be described.

  FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the image forming apparatus 1 includes an image forming unit that forms an image using each toner of yellow Y, magenta M, cyan C, and black Bk. Each of the image forming units PY, PM, PC, and PK has the same configuration except for the color of the toner.

  First, as an explanation of the image forming unit, the image forming unit PY will be described as a representative. The photosensitive drum 20Y, which is an image carrier, is rotatably provided. The primary charger 21Y uniformly charges the surface of the rotating photosensitive drum 20Y. Thereafter, the uniformly charged surface is exposed by an exposure device 22Y such as a laser in accordance with an information signal, thereby forming an electrostatic latent image on the photosensitive drum 20Y. The formed electrostatic latent image is visualized as a toner image on the photosensitive drum 20Y by the developing device 30Y. In this embodiment, a two-component development method using toner and a carrier is adopted.

  Next, the toner image visualized on the photosensitive drum 20Y is transferred to the intermediate transfer belt 24 by the primary transfer portion 23Y. Such a process is performed in each image forming unit, and a color image is formed on the intermediate transfer belt 24. The toner image formed on the intermediate transfer belt 24 is conveyed to the secondary transfer unit 29 and is secondarily transferred to the recording material 27 conveyed on the sheet conveyance path 28 in the secondary transfer unit 29. The recording material 27 on which the toner image is formed is further fixed on the recording material 27 by heat and pressure by the fixing device 25. The toner remaining on the photosensitive drum 20Y is removed by the drum cleaner 26Y.

  The photosensitive drum 20Y, the developing device 30Y, the primary charger 21Y, and the drum cleaner 26Y are provided in the process unit 10Y.

  Since the configuration of the image forming unit is the same except for the color of the toner, the contents described below apply to all the colors in the process unit 10, the developing device 30, the photosensitive drum 20, and the like.

(Process unit configuration)
Next, the process unit 10 will be described.

  FIG. 2 is a perspective view showing the configuration of the process unit 10.

  As shown in the figure, the developing device 30 can be inserted into and removed from the process unit 10.

  FIG. 3 is a perspective view showing a state in which the developing device 30 is attached to the process unit 10.

  As shown in the figure, an operation lever 31 is provided to pressurize the developing device 30 to the photosensitive drum 20 after the developing device 30 is inserted into the process unit 10. By operating the operation lever 31 in the direction A in the figure, the developing device 30 is slid in the direction of the arrow B in the figure and pressed against the photosensitive drum 20.

  FIG. 4 is a perspective view showing a configuration of a mechanism for moving the developing device 30 of the process unit 10.

  Next, the movement of the developing device 30 will be described with reference to FIG.

  The process unit 10 that holds the developing device 30 and the photosensitive drum 20 includes a pressing member 32 that presses the developing device 30 against the photosensitive drum 20 therein.

  The pressing member 32 can be moved left and right by operating the operation lever 31 back and forth. Specifically, by pressing the operation lever 31 toward the depth, the pressing member 32 operates from left to right, and when the pressing member 32 presses the back surface of the developing device 30, the developing device 30 moves the photosensitive drum 20. It is configured to be pressed against. When the developing device 30 is separated from the photosensitive drum 20, the pressing member 32 is moved from right to left by pulling the operation lever 31 toward the front, and the developing device 30 is separated from the photosensitive drum 20. The attaching / detaching operation of the developing device 30 is performed by a service person when replacing the developing device 30 that has reached the end of life or when investigating the cause when an abnormal image occurs.

  FIG. 5 is a cross-sectional view showing the developing device 30 and its surroundings when the developing device 30 is stored in the process unit 10. FIG. 5A is a cross-sectional view of the developing device 30, the photosensitive drum 20, and the pressing member 32 when viewed from the front of the main body. FIG. 5B is an enlarged view of a developing nip portion formed by the developing sleeves 35 and 36 (developer carrying member) and the photosensitive drum 20 shown in FIG. FIG. 5C is an enlarged view of the peripheral portion of the developing sleeve 36 shown in FIG.

  Next, the relationship between the developing device 30 and the photosensitive drum 20 will be described in detail with reference to these drawings. The developing device 30 includes a developing sleeve 35 and a developing sleeve 36. Further, the developing device 30 includes a screw 34 that conveys the developer in the developing container 33. As shown in FIG. 5B, the developing sleeve 35 and the developing sleeve 36 are arranged on the left side of the photosensitive drum 20 with a certain SD gap D1, D2 with respect to the photosensitive drum. If the SD gap is too wide, the developability deteriorates, and if it is too narrow, the developer overflows. In addition, there is a characteristic that the image density difference increases when the uniformity of the gaps in the front, center, and back side in the thrust direction is lost.

(Formation of SD gap)
Next, formation of the SD gap will be described.

  FIG. 6 is a perspective view of the developing device 30.

  As shown in the figure, spacer rollers 40 and 41 including bearings are provided at both ends of the developing sleeve 35 and the developing sleeve 36 on the front side and the back side in the thrust direction so that the SD gap is within an appropriate range. ing. The spacer rollers 40 and 41 are rotatable with respect to the developing sleeves 35 and 36 by including a bearing. 5B, the outer peripheral portions of the spacer rollers 40 and 41 are abutted against the abutting members 42 and 43 disposed on the front side and the back side of the photosensitive drum 20, so that the surface of the photosensitive drum 20 and A gap (SD gap) is formed between the surfaces of the developing sleeves 35 and 36.

  FIG. 7 is a perspective view of the photosensitive drum 20 and its periphery.

  As shown in FIGS. 6 and 7, the positioning of the developing device 30 with respect to the photosensitive drum 20 is performed by two bosses J1 and J2 provided on the back side and the near side in the axial direction of the developing sleeves 35 and 36 (FIG. 6). And the holes K1 and K2 (see FIG. 7) provided in the abutting members 42 and 43 are engaged with each other.

  Further, only the hole K1 of the abutting member 42 on the near side is provided with play in the vertical direction (H in FIG. 5C).

  FIG. 8 is a view showing the relationship between the developing sleeves 35 and 36 and the photosensitive drum 20 when the developing device 30 is pressurized.

  As shown in the figure, in a state where the developing device 30 is pressed toward the photosensitive drum 20 by the pressing member 32, the developing device 30 gives priority to the four spacer rollers abutting and balances the ground pressure of each spacer roller. Change posture so that is taken. Changing the posture of the developing device 30 causes a deviation in the bus line between the developing sleeves 35 and 36 and the photosensitive drum 20, but priority is given to four spacer rollers abutting against each other.

(Configuration of the developing device 30)
Next, the configuration of the developing device 30 will be described in detail with reference to FIG.

  The developing device 30 includes a developing container 33. Bearings are provided at both ends of the developing sleeves 35 and 36, and the developing sleeves 35 and 36 are rotatably installed with respect to the developing container 33 by engaging the bearings with the developing container 33. A blade support member 37 and an upper lid 38 are attached to the upper surface of the developing device 30 so as to cover the developing container 33. The blade support member 37 and the upper lid 38 are each screw-fixed to the developing container 33, and the blade support member 37 and the upper lid 38 are also screw-fixed. Further, as shown in FIG. 5, the blade support member 37 has a curved portion parallel to the longitudinal direction of the developing sleeves 35 and 36, and a blade 39 (layer thickness regulating) that regulates the layer thickness of the developer on the surface E of the curved portion. Member) is attached.

  Next, the function of the blade 39 will be described.

  The developer accommodated in the developing container 33 is carried on a plurality of developing sleeves 35 and 36. The layer thickness of the developer carried on the developing sleeves 35 and 36 is regulated by a gap (interval, SB gap) formed by the tip of the blade 39 and the developing sleeve 35. If the SB gap is too small, the developer layer thickness on the developing sleeves 35 and 36 becomes thin, and there is a problem that the toner supplied to the photosensitive drum 20 is reduced and the density is lowered. If the SB gap is too large, the toner moving from the developing sleeves 35 and 36 to the photosensitive drum 20 is excessively supplied, and the toner is clogged at the SD gap portion between the developing sleeves 35 and 36 and the photosensitive drum 20. Problems arise. Therefore, the SB gap needs to be adjusted to an appropriate range.

(Assembling a conventional developing device)
Next, an assembling procedure of the conventional developing device 30 will be described.

  FIG. 9 is a diagram showing an assembling procedure of a conventional developing device. In the assembly process, conventionally, strength members (strength members) such as the blade support member 37 and the upper lid 38 are assembled without fixing the developing device 30 (FIG. 9A). At this time, the developing device 30 is distorted, twisted, or bent due to a force received when the upper lid 38 and the blade support member 37 are screw-fixed to the developing container 33 or a twisting of the developing container 33 which is held by the developing container 33 as a single unit. Solidified by strength members in state.

  Next, the developing device 30 having distortion or the like is placed on the jig 100 in order to adjust the SB gap (FIG. 9B). The developing device 30 placed on the jig 100 is pressed toward the abutting members 142 and 143 by the pressing member 132 (FIG. 9C). Then, the spacer rollers 40 and 41 installed at the four ends of the developing sleeve 35 and the developing sleeve 36 abut against the abutting members 142 and 143. Here, unlike the main body, no play is provided in the positioning portion (L in FIG. 9C) of the developing device 30 provided in the jig 100.

  Generally, in order to obtain stable surface contact, it is basic to ground three points. When the spacer rollers 40 and 41 are four places, one place is in a floating state. Therefore, in order to abut the spacer rollers 40 and 41 at all four locations, the developing device 30 is deformed to the position where the four spacer rollers 40 and 41 abut on the jig 100 by the pressing member 132, and the distortion of the developing device 30 is corrected. Is done. In this state, an appropriate SB gap can be obtained by adjusting the position of the blade in the G direction in FIG. When the developing device 30 is removed from the jig 100, the developing device 30 is released from being pressed by the pressing member 132 and is distorted again, and the SB gap is shifted by an amount corresponding to the distortion of the developing device 30 from the time of adjustment.

  Such a conventional assembly / adjustment process has the following problems.

  First, there is a problem that the SD gap is shifted before, in the center, and at the back of the developing sleeves 35 and 36 due to the deviation of the bus line between the developing sleeves 35 and 36 and the photosensitive drum 20.

  FIG. 10 is a view of the developing sleeves 35 and 36 and the photosensitive drum 20 as viewed from the developing device 30 side.

  As shown in the figure, when the developing sleeve 35 is displaced from the photosensitive drum 20 in the bus line, the center of the SD gap is narrower toward the back side and the front side. When the SD gap is shifted in the longitudinal direction of the developing sleeves 35 and 36 as described above, the developability with respect to the photosensitive drum 20 is not uniform in the longitudinal direction, and a density step is generated in the image. A play is provided for positioning the developing sleeves 35 and 36 and the photosensitive drum 20 in the apparatus main body. For this reason, when the developing device 30 having distortion is pressed by the pressing member 32 in the main body, the posture of the developing device 30 is naturally adjusted so that the ground pressures at the four positions of the spacer rollers 40 and 41 are balanced. . As a result, misalignment between the developing sleeves 35 and 36 and the photosensitive drum 20 occurs.

  Secondly, there arises a problem that the SB gap adjusted on the jig 100 is shifted in the main body. That is, by providing play in the positioning of the developing device 30 and the photosensitive drum 20, the distortion of the developing device 30 is corrected in the main body in exchange for the fact that the four spacer rollers 40 and 41 easily come into contact with each other. Without spacer roller. This is because when the SB gap is adjusted on the jig as described above, since the distortion of the developing device 30 is corrected, the distortion state of the developing device 30 differs between the jig 100 and the main body. Because.

  Thirdly, as a problem in the configuration of the developing device 30, there is a problem that the developing sleeves 35 and 36 are easily twisted due to service distribution or handling by a service person. This is because in the conventional assembly process, it is necessary to change the posture of the developing device 30 having distortion until the spacer rollers 40 and 41 are grounded at all four points, and therefore the rigidity of the developing device 30 must be lowered.

(Assembly of developing device of this embodiment)
Therefore, in this embodiment, these problems are solved by assembling and adjusting the developing device as follows.

  FIG. 11 is a view showing an assembly and adjustment process of the developing device 30 in this embodiment.

  First, the developing sleeve 35, the developing sleeve 36, the screw 34, and the like are assembled in the developing container 33. Next, the developing device 30 is placed on the jig 100 for adjusting the SB gap (FIG. 11A). At the stage of placing on the jig 100, the spacer rollers 40 and 41 provided on the developing sleeve 35 and the developing sleeve 36 are pressed against the abutting members 142 and 143 by the pressing member 32. At this time, the strength member (strength member) is not yet attached, and the developing device 30 has a low rigidity, so that the spacer rollers 40 and 41 are in a state where the four abutting members 142 abut on the abutting member 142 easily.

  Then, the blade support member 37 and the upper lid 38 (strength member) attached to the upper side of the developing device 30 are assembled with the spacer rollers 40 and 41 being abutted against each other (FIG. 11B). The blade support member 37 and the upper lid 38 are each fixed to the developing container 33 with screws, but in the present embodiment, the blade support member 37 and the upper lid 38, which were not conventionally fixed, are also firmly fixed. The rigidity of the developing device 30 is increased. That is, the upper lid 38 functions as a lid of the developing device 30 and also functions as a strength member that gives strength to the developing device 30.

  By performing the assembly process as described above, a state in which the distortion of the developing device 30 is corrected can be created, and then the developing device 30 can be fixed by strength members such as the blade support member 37 and the upper lid 38. Thereby, even if the developing device 30 is removed from the jig 100, the developing device 30 that is not twisted can be obtained. The developing device 30 is adjusted so that the SB gap becomes a predetermined value by moving the blade 39 on the jig 100 in the direction of arrow G in FIG.

  In the present embodiment, the distortion, twist, and deflection of the developing device 30 can be reduced by performing the assembly process as described above. Therefore, the amount of deviation of the bus line between the developing sleeves 35 and 36 and the photosensitive drum 20 which occurs in order to prioritize the contact of the four spacer rollers 40 and 41 is reduced, and the difference between the front, middle and back of the SD gap can be suppressed.

  Further, since the difference in the distortion state of the developing device 30 is small between the jig 100 and the inside of the main body, the difference in the SB gap due to the change in the distortion state of the developing device 30 can also be reduced. Furthermore, since the rigidity of the developing device 30 can be increased, it is possible to suppress the risk of SB gap change due to service logistics or serviceman handling.

  That is, in the present embodiment, at least a part of the assembly of the developing device 30 is performed on the jig 100.

Second Embodiment
In the first embodiment, the adjustment of the SB gap is performed on the jig 100, but in the present embodiment, the adjustment is performed on the image forming apparatus 1. That is, at least a part of the assembly of the developing device 30 is performed on the image forming apparatus 1.

  FIG. 12 is a view showing the periphery of the photosensitive drum 20 and the developing device 30 in the image forming apparatus 1.

  In the first embodiment, since a dimensional difference is generated between the jig 100 and the components in the main body, a difference is generated between the SB gap adjusted on the jig 100 and the SB gap on the main body. However, in the present embodiment, since an appropriate SB gap is obtained by adjusting the position of the blade 39 in the G direction on the image forming apparatus 1 as shown in FIG. 12, the accuracy of the SB gap in the main body is further improved. Can be made.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 10 ... Process unit 20 ... Photosensitive drum 30 ... Developing device 31 ... Operation lever 32, 132 ... Pushing member 33 ... Developing container 35, 36 ... Developing sleeve 38 ... Upper lid 39 ... Blade 42, 43, 142, 143 ... Abutting member 100 ... Jig

Claims (11)

A developing device for use in an image forming apparatus, comprising: a developing container for storing a developer; and a developing device assembly method including a strength member for imparting strength to the developing device,
A first step of deforming the developing container by pressing the developing container against an abutting member;
And a second step of attaching a strength member that gives strength to the developing device to the developing container in a state where the developing container is deformed by the first step. The developing device further comprises a developer carrier that carries the developer,
The method of assembling a developing device according to claim 1, further comprising a step of attaching the developer carrying member to the developing container before the first step. The developing device further includes a layer thickness regulating member that regulates the layer thickness of the developer on the developer carrying member,
The method of assembling a developing device according to claim 2, further comprising a step of adjusting a distance between the layer thickness regulating member and the developer carrier after the second step.   In the first step, when the developing device is mounted on the image forming apparatus, a predetermined distance is provided between the surface of the image carrier provided on the image forming apparatus and the surface of the developer carrier. 4. The method of assembling a developing device according to claim 2, wherein the developing container is deformed by pressing the developing container against the abutting member.   5. The abutting member is provided in a jig for assembling the developing device, and at least a part of the assembling of the developing device is performed using the jig. The method of assembling the developing device according to any one of the above.   6. The method of assembling a developing device according to claim 5, wherein, in the first step, the developing container is pressed against the abutting member by a pressing member provided on the jig.   5. The abutting member is provided in the image forming apparatus, and at least a part of the assembly of the developing device is performed inside the image forming apparatus. 4. A method for assembling the developing device according to 1.   The method of assembling the developing device according to claim 7, wherein in the first step, the developing container is pressed against the abutting member by a pressing member provided in the image forming apparatus.   The method for assembling a developing device according to claim 1, wherein the strength member is at least a part of a lid of the developing container.   10. The method of assembling a developing device according to claim 3, wherein the layer thickness regulating member is provided on the strength member.   11. The developing device assembling method according to claim 2, wherein the developer carrying member has a plurality of developing sleeves.

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