Manufacturing method of developing device

Abstract

To make a gap between a developer carrier and the regulating part within a predetermined range in the longitudinal direction of the developer carrier when the regulating blade is fixed to an attachment part of a developing frame body, even if a resin regulating blade having a low accuracy of straightness of a regulating part for regulating the amount of developer carried on the developer carrier is used. A force is applied to the regulating blade to bend it so that the gap between the developer carrier supported on the developing frame and the regulating blade attached to the attachment portion of the developing frame is within a predetermined range in the longitudinal direction of the developer carrier.The regulating blade is bent by the force applied to it, and the regulating blade is fixed to the attachment portion in a state where the gap is within the predetermined range in the longitudinal direction of the developer carrier.

Description

[Technical field]

[0001] The present invention relates to a regulating blade made of resin. A manufacturing method of a developing device comprising: Regarding. [Background technology]

[0002] The developing device includes a regulating blade (developer regulating member) having a coat amount regulating surface (regulating portion) that regulates the amount of developer (developer coat amount) carried on the surface of a developer carrier that carries a developer to develop an electrostatic latent image formed on the image carrier. The regulating blade is disposed facing the developer carrier over the longitudinal direction of the developer carrier with a predetermined gap (hereinafter referred to as SB gap G) between the surface of the developer carrier. The SB gap G is the shortest distance between the surface of the developer carrier supported by the frame (developer frame) of the developer container and the coat amount regulating surface of the regulating blade attached to the frame of the developer container. By adjusting the size of this SB gap G, the amount of developer transported to the development area where the developer carrier faces the image carrier is adjusted.

[0003] The developing device described in Patent Document 1 includes a resin developer regulating member molded from resin, and a resin developing container frame molded from resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-197175 A Summary of the Invention [Problem to be solved by the invention]

[0005] As the width of the sheet on which an image is formed increases, the area of ​​the coat amount control surface corresponding to the image area that can be formed on the image carrier increases, and the length of the longitudinal direction of the control blade increases. When a control blade with a large longitudinal length is molded from resin, it is difficult to guarantee the straightness of the coat amount control surface of the resin-made control blade molded from resin. This is because, when a control blade with a large longitudinal length is molded from resin, the rate at which the thermally expanded resin thermally contracts tends to vary. Therefore, in a resin-made control blade, the SB gap G tends to vary in the longitudinal direction of the developer carrier due to the straightness of the coat amount control surface of the control blade as the longitudinal length of the control blade increases. If the SB gap G varies in the longitudinal direction of the developer carrier, there is a risk of unevenness in the amount of developer carried on the surface of the developer carrier in the longitudinal direction of the developer carrier.

[0006] Therefore, in a developing device equipped with a resin regulating blade, it is desirable to ensure that the SB gap G is within a predetermined range in the longitudinal direction of the developer carrier when the regulating blade is fixed to the mounting portion of the developing frame, regardless of the straightness of the coat amount regulating surface of the regulating blade.

[0007] The present invention has been made in view of the above problems. A manufacturing method of a developing device in which the size of the gap between the developer carrier supported by the developing frame and the resin-made regulating blade attached to the attachment portion of the developing frame is within a predetermined range along the longitudinal direction of the developer carrier. The purpose of this invention is to provide [Means for solving the problem]

[0008] In order to achieve the above object, a method for manufacturing a developing device according to one aspect of the present invention has the following configuration: That is, a method for manufacturing a developing device including a developer carrier that carries and transports a developer to a development position, a resin-made regulating blade that is disposed opposite to the developer carrier in a non-contact manner and that regulates the amount of developer carried on the developer carrier, and a resin-made developing frame that has an attachment portion to which the regulating blade is attached and supports the developer carrier, the method including a coating step of coating an adhesive on the attachment portion, and a method for manufacturing a developing device including a coating step of coating an adhesive on the attachment portion after the adhesive applied to the attachment portion in the coating step is brought into contact with the regulating blade and before the adhesive applied to the attachment portion in the coating step is completely cured, the method including a coating step of coating an adhesive on the attachment portion, and a method for manufacturing a developing device including a coating step of coating an adhesive on the attachment portion ... Place fixed Tolerance of The present invention is characterized by having a positioning process that adjusts the force for bending the regulating blade so that it is within a certain range, and determines the position at which the regulating blade is attached to the mounting portion while applying the adjusted force to each of multiple points in the longitudinal direction of the regulating blade. In order to achieve the above object, a manufacturing method of a developing device according to another aspect of the present invention has the following configuration: That is, a manufacturing method of a developing device including a developer carrier that carries and transports a developer to a development position, a resin-made regulating blade that is disposed opposite to the developer carrier in a non-contact manner and that regulates the amount of developer carried on the developer carrier, and a resin-made developing frame that has an attachment portion to which the regulating blade is attached and supports the developer carrier, the manufacturing method including a coating step of coating an adhesive on the regulating blade, and a method of manufacturing a developing device including a coating step of coating an adhesive on the regulating blade, and a method of manufacturing a developing device including a coating step of coating an adhesive on the regulating blade, the method including a coating step of contacting the adhesive applied to the regulating blade with the attachment portion and a method of manufacturing a developing device including a coating step of contacting the adhesive applied to the regulating blade with the attachment portion and a method of manufacturing a developing device including a coating step of coating an adhesive on the regulating blade, the method ... Place fixed Tolerance ofThe present invention is characterized by having a positioning process that adjusts the force for bending the regulating blade so that it is within a certain range, and determines the position at which the regulating blade is attached to the mounting portion while applying the adjusted force to each of multiple points in the longitudinal direction of the regulating blade. Effect of the Invention

[0009] According to the present invention, The size of the gap between the developer carrier supported by the developing frame and the resin-made regulating blade attached to the attachment portion of the developing frame can be set within a predetermined range along the longitudinal direction of the developer carrier. . [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a configuration of an image forming apparatus. [Diagram 2] FIG. 2 is a perspective view illustrating a configuration of a developing device according to the first embodiment. [Diagram 3] FIG. 2 is a perspective view illustrating a configuration of a developing device according to the first embodiment. [Figure 4] 1 is a cross-sectional view showing a configuration of a developing device according to a first embodiment. [Diagram 5] FIG. 2 is a perspective view showing a configuration of a resin developing frame (single unit). [Figure 6] FIG. 2 is a perspective view showing the configuration of a resin doctor blade (single unit). [Figure 7] FIG. 2 is a schematic diagram for explaining the rigidity of a resin doctor blade (single unit). [Figure 8] 4 is a schematic diagram for explaining the rigidity of a resin developing frame (single unit). FIG. [Figure 9] 1A to 1C are schematic diagrams for explaining steps of a method for fixing a resin doctor blade. [Figure 10] 1A to 1C are schematic diagrams for explaining steps of a method for fixing a resin doctor blade. [Figure 11] 1A to 1C are schematic diagrams for explaining steps of a method for fixing a resin doctor blade. [Figure 12] 1A to 1C are schematic diagrams for explaining steps of a method for fixing a resin doctor blade. [Figure 13]1A to 1C are schematic diagrams for explaining steps of a method for fixing a resin doctor blade. [Figure 14] 1A to 1C are schematic diagrams for explaining steps of a method for fixing a resin doctor blade. [Figure 15] 10 is a cross-sectional view for explaining deformation of a resin doctor blade caused by agent pressure. FIG. [Figure 16] FIG. 2 is a perspective view illustrating deformation of a resin doctor blade caused by a temperature change. [Figure 17] FIG. 11 is a perspective view showing a configuration of a developing device according to a second embodiment. [Figure 18] FIG. 11 is a cross-sectional view showing the configuration of a developing device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present invention, and not all of the combinations of features described in the first embodiment are necessarily essential to the solution of the present invention. The present invention can be implemented in various applications, such as printers, various printing machines, copiers, FAX machines, and multifunction machines.

[0012] [First embodiment] (Configuration of Image Forming Apparatus) First, the configuration of an image forming apparatus according to a first embodiment of the present invention will be described with reference to the cross-sectional view of Fig. 1. As shown in Fig. 1, an image forming apparatus 60 includes an endless intermediate transfer belt (ITB) 61 as an intermediate transfer body, and four image forming units 600 arranged from the upstream side to the downstream side along the rotation direction (the direction of arrow C in Fig. 1) of the intermediate transfer belt 61. Each of the image forming units 600 forms a toner image of each color, yellow (Y), magenta (M), cyan (C), and black (Bk).

[0013] The image forming unit 600 includes a rotatable photoconductor drum 1 as an image carrier. The image forming unit 600 also includes a charging roller 2 as a charging means, a developing device 3 as a developing means, a primary transfer roller 4 as a primary transfer means, and a photoconductor cleaner 5 as a photoconductor cleaning means, which are arranged along the rotation direction of the photoconductor drum 1.

[0014] Each of the developing devices 3 is detachably attached to the image forming apparatus 60. Each of the developing devices 3 has a developing container 50 that contains a two-component developer (hereinafter simply referred to as developer) containing a non-magnetic toner (hereinafter simply referred to as toner) and a magnetic carrier. Each of the toner cartridges that contain the toner of each color Y, M, C, and Bk is detachably attached to the image forming apparatus 60. The toner of each color Y, M, C, and Bk is supplied to each of the developing containers 50 through a toner transport path. Details of the developing device 3 will be described later with reference to FIGS. 2 to 4, and details of the developing container 50 will be described later with reference to FIG. 5.

[0015] The intermediate transfer belt 61 is stretched by a tension roller 6, a driven roller 7a, a primary transfer roller 4, a driven roller 7b, and a secondary transfer inner roller 66, and is driven to be transported in the direction of arrow C in Fig. 1. The secondary transfer inner roller 66 also serves as a drive roller that drives the intermediate transfer belt 61. As the secondary transfer inner roller 66 rotates, the intermediate transfer belt 61 rotates in the direction of arrow C in Fig. 1.

[0016] The intermediate transfer belt 61 is pressed by a primary transfer roller 4 from the back side of the intermediate transfer belt 61. In addition, by bringing the intermediate transfer belt 61 into contact with the photosensitive drum 1, a primary transfer nip portion serving as a primary transfer portion is formed between the photosensitive drum 1 and the intermediate transfer belt 61.

[0017] An intermediate transfer body cleaner 8 as a belt cleaning means is in contact with a position facing the tension roller 6 across the intermediate transfer belt 61. Also, a secondary transfer outer roller 67 as a secondary transfer means is disposed at a position facing the secondary transfer inner roller 66 across the intermediate transfer belt 61. The intermediate transfer belt 61 is sandwiched between the secondary transfer inner roller 66 and the secondary transfer outer roller 67. As a result, a secondary transfer nip portion as a secondary transfer portion is formed between the secondary transfer outer roller 67 and the intermediate transfer belt 61. In the secondary transfer nip portion, a predetermined pressure force and a transfer bias (electrostatic load bias) are applied to cause a toner image to adhere to the surface of the sheet S (for example, paper, film, etc.).

[0018] The sheets S are stored in a stacked state in a sheet storage section 62 (e.g., a feeding cassette or a feeding deck). The feeding means 63 feeds the sheets S in accordance with the image formation timing, for example, using a friction separation method using a feeding roller or the like. The sheets S sent out by the feeding means 63 are transported to a registration roller 65 arranged midway along a transport path 64. After skew correction and timing correction are performed by the registration roller 65, the sheets S are transported to a secondary transfer nip section. In the secondary transfer nip section, the timing of the sheets S and the toner image coincides, and secondary transfer is performed.

[0019] A fixing device 9 is disposed downstream of the secondary transfer nip portion in the conveying direction of the sheet S. The fixing device 9 applies a predetermined pressure and heat to the sheet S conveyed to the fixing device 9, thereby melting and fixing the toner image on the surface of the sheet S. The sheet S with the image fixed in this manner is discharged directly to a discharge tray 601 by forward rotation of discharge rollers 69.

[0020] When double-sided image formation is performed, the discharge rollers 69 are rotated in the forward direction to convey the sheet S until the rear end passes through the switching flapper 602, and then the discharge rollers 69 are rotated in the reverse direction. As a result, the sheet S is conveyed to a double-sided conveying path 603 with the leading and trailing ends switched. Thereafter, in accordance with the timing for the next image formation, the sheet S is conveyed again to the conveying path 64 by the re-feed rollers 604.

[0021] (Image formation process) During image formation, the photoconductor drum 1 is rotated by a motor. The charging roller 2 uniformly charges the surface of the photoconductor drum 1 that is rotated in advance. The exposure device 68 forms an electrostatic latent image on the surface of the photoconductor drum 1 that has been charged by the charging roller 2, based on a signal of image information input to the image forming device 60. The photoconductor drum 1 is capable of forming electrostatic latent images of a plurality of sizes.

[0022] The developing device 3 has a rotatable developing sleeve 70 as a developer carrier that carries a developer. The developing device 3 develops the electrostatic latent image formed on the surface of the photosensitive drum 1 by using the developer carried on the surface of the developing sleeve 70. As a result, toner adheres to the exposed portion on the surface of the photosensitive drum 1, and a visible image is formed. A transfer bias (electrostatic load bias) is applied to the primary transfer roller 4, and the toner image formed on the surface of the photosensitive drum 1 is transferred onto the intermediate transfer belt 61. A small amount of toner (transfer residual toner) remaining on the surface of the photosensitive drum 1 after the primary transfer is collected by the photosensitive cleaner 5 and prepared for the next image forming process.

[0023] The image forming process of each color, which is processed in parallel by the image forming unit 600 of each color of Y, M, C, and Bk, is performed at a timing to sequentially superimpose the toner image of the upstream color that has been primarily transferred onto the intermediate transfer belt 61. As a result, a full-color toner image is formed on the intermediate transfer belt 61, and the toner image is conveyed to the secondary transfer nip portion. A transfer bias is applied to the secondary transfer outer roller 67, and the toner image formed on the intermediate transfer belt 61 is transferred to the sheet S conveyed to the secondary transfer nip portion. A small amount of toner (transfer residual toner) remaining on the intermediate transfer belt 61 after the sheet S has passed through the secondary transfer nip portion is collected by the intermediate transfer body cleaner 8. The fixing device 9 fixes the toner image transferred onto the sheet S. The recording material S that has been subjected to the fixing process by the fixing device 9 is discharged to the discharge tray 601.

[0024] The series of image forming processes as described above is now complete, and the next image forming operation is prepared.

[0025] (Configuration of the developing device) Next, the configuration of the developing device 3 according to the first embodiment of the present invention will be described with reference to the perspective view of Fig. 2, the perspective view of Fig. 3, and the cross-sectional view of Fig. 4. Fig. 4 is a cross-sectional view of the developing device 3 taken along the cross section H of Fig. 2.

[0026] The developing device 3 includes a developing container 50 that is made up of a resin developing frame (hereinafter simply referred to as the developing frame 30) and a resin cover frame (hereinafter simply referred to as the cover frame 40) that is formed separately from the developing frame 30 and is also made of resin. Figures 2 and 4 show a state in which the cover frame 40 is attached to the developing frame 30, while Figure 3 shows a state in which the cover frame 40 is not attached to the developing frame 30. Details of the configuration of the developing frame 30 (single unit) will be described later with reference to Figure 5.

[0027] The developing container 50 has an opening at a position corresponding to a developing region where the developing sleeve 70 faces the photosensitive drum 1. The developing sleeve 70 is rotatably disposed relative to the developing container 50 so that a portion of the developing sleeve 70 is exposed at the opening of the developing container 50. Bearings 71, which are bearing members, are provided at both ends of the developing sleeve 70.

[0028] The inside of the developing container 50 is partitioned by a partition wall 38 extending in the vertical direction into a developing chamber 31 as a first chamber and an agitating chamber 32 as a second chamber. The developing chamber 31 and the agitating chamber 32 are connected at both ends in the longitudinal direction via two communication portions 39 that the partition wall 38 has. Therefore, the developer can communicate between the developing chamber 31 and the agitating chamber 32 via the communication portions 39. The developing chamber 31 and the agitating chamber 32 are arranged side by side in the horizontal direction.

[0029] A magnet roll is fixedly disposed inside the developing sleeve 70, which has a plurality of magnetic poles along the rotation direction of the developing sleeve 70 and serves as a magnetic field generating means for generating a magnetic field for carrying the developer on the surface of the developing sleeve 70. The developer in the developing chamber 31 is pumped up by the influence of the magnetic field caused by the magnetic poles of the magnet roll, and is supplied to the developing sleeve 70. Since the developer is supplied from the developing chamber 31 to the developing sleeve 70 in this manner, the developing chamber 31 is also called a supply chamber.

[0030] In the developing chamber 31, a first conveying screw 33 serving as a conveying means for stirring and conveying the developer in the developing chamber 31 is disposed opposite the developing sleeve 70. The first conveying screw 33 includes a rotating shaft 33a serving as a rotatable shaft portion, and a spiral blade portion 33b serving as a developer conveying portion provided along the outer periphery of the rotating shaft 33a, and is rotatably supported by the developing container 50. Bearing members are provided on both ends of the rotating shaft 33a.

[0031] Further, in the stirring chamber 32, a second conveying screw 34 is disposed as a conveying means for stirring the developer in the stirring chamber 32 and conveying the developer in the opposite direction to the first conveying screw 33. The second conveying screw 34 includes a rotating shaft 34a as a rotatable shaft portion and a spiral blade portion 34b as a developer conveying portion provided along the outer periphery of the rotating shaft 34a, and is rotatably supported by the developing container 50. Bearing members are provided on both ends of the rotating shaft 34a. The developer circulates between the developing chamber 31 and the stirring chamber 32 via a communication portion 39 as the first conveying screw 33 and the second conveying screw 34 are driven to rotate.

[0032] A regulating blade (hereinafter referred to as doctor blade 36) serving as a developer regulating member for regulating the amount of developer carried on the surface of the developing sleeve 70 (also referred to as developer coat amount) is attached to the developing container 50 so as to face the surface of the developing sleeve 70 in a non-contact manner. The doctor blade 36 has a coat amount regulating surface 36r serving as a regulating portion for regulating the amount of developer carried on the surface of the developing sleeve 70. The doctor blade 36 is a resin doctor blade molded from resin. The configuration of the doctor blade 36 (single unit) will be described later with reference to FIG. 6.

[0033] The doctor blade 36 is disposed opposite to the developing sleeve 70 with a predetermined gap (hereinafter referred to as SB gap G) between the developing sleeve 70 and the developing sleeve 70 across the longitudinal direction of the developing sleeve 70 (i.e., the direction parallel to the rotation axis direction of the developing sleeve 70). In the present invention, the SB gap G is the shortest distance between an area of ​​the developing sleeve 70 corresponding to the maximum image area that can be formed on the surface of the photosensitive drum 1 (so-called the maximum image area of ​​the developing sleeve 70) and an area of ​​the doctor blade 36 corresponding to the maximum image area (so-called the maximum image area of ​​the doctor blade 36). In the first embodiment, since the photosensitive drum 1 can form electrostatic latent images of multiple sizes, the maximum image area refers to an image area corresponding to the largest size (e.g., A3 size) among the multiple sizes of image areas that can be formed on the photosensitive drum 1. On the other hand, in a modified example in which the photosensitive drum 1 can form electrostatic latent images of only one size, the maximum image area is interpreted as referring to the image area of ​​that one size that can be formed on the photosensitive drum 1.

[0034] The doctor blade 36 is disposed substantially opposite to the peak position of the magnetic flux density of the magnetic pole of the magnet roll. The developer supplied to the developing sleeve 70 is affected by the magnetic field of the magnetic pole of the magnet roll. The developer regulated and scraped off by the doctor blade 36 tends to accumulate in the upstream portion of the SB gap G. As a result, a developer pool is formed upstream of the doctor blade 36 in the rotation direction of the developing sleeve 70. Then, a part of the developer in the developer pool is transported to pass through the SB gap G as the developing sleeve 70 rotates. At this time, the layer thickness of the developer passing through the SB gap G is regulated by the coat amount regulating surface 36r of the doctor blade 36. In this way, a thin layer of developer is formed on the surface of the developing sleeve 70.

[0035] A predetermined amount of developer carried on the surface of the developing sleeve 70 is transported to the developing area as the developing sleeve 70 rotates. Therefore, the amount of developer transported to the developing area is adjusted by adjusting the size of the SB gap G. In the first embodiment, the size of the SB gap G that is targeted when adjusting the size of the SB gap G (so-called target value of the SB gap G) is set to about 300 μm.

[0036] The developer transported to the development area stands up in the development area to form magnetic ears. When these magnetic ears come into contact with the photosensitive drum 1, the toner in the developer is supplied to the photosensitive drum 1. Then, the electrostatic latent image formed on the surface of the photosensitive drum 1 is developed as a toner image. The developer on the surface of the development sleeve 70 after passing through the development area and supplying the toner to the photosensitive drum 1 (hereinafter referred to as the developer after the development process) is peeled off from the surface of the development sleeve 70 by a repulsive magnetic field formed between the magnetic poles of the same polarity of the magnet roll. The developer after the development process peeled off from the surface of the development sleeve 70 falls into the development chamber 31 and is collected in the development chamber 31.

[0037] As shown in FIG. 4, the developer container 50 is provided with a developer guide portion 35 for guiding the developer so that it is transported toward the SB gap G. The developer guide portion 35 and the developing frame 30 are integrally formed, and the developer guide portion 35 and the doctor blade 36 are separately formed. The developer guide portion 35 is formed inside the developing frame 30, and is disposed upstream of the coat amount control surface 36r of the doctor blade 36 in the rotation direction of the developing sleeve 70. The developer guide portion 35 stabilizes the flow of the developer and adjusts it to a predetermined developer density, thereby making it possible to regulate the weight of the developer at the position where the coat amount control surface 36r of the doctor blade 36 is closest to the surface of the developing sleeve 70.

[0038] 4, the cover frame 40 is formed separately from the developing frame 30 and attached to the developing frame 30. The cover frame 40 covers a part of the opening of the developing frame 30 so that a part of the outer circumferential surface of the developing sleeve 70 is covered over the entire area in the longitudinal direction of the developing sleeve 70. At this time, the cover frame 40 covers a part of the opening of the developing frame 30 so that the developing region of the developing sleeve 70 facing the photosensitive drum 1 is exposed. In the first embodiment, the cover frame 40 is fixed to the developing frame 30 by ultrasonic bonding, but the method of fixing the cover frame 40 to the developing frame 30 may be any method such as screw fastening, snap fitting, bonding, welding, etc.

[0039] Next, the configuration of the developing frame 30 (single unit) will be described with reference to the perspective view of Fig. 5. Fig. 5 shows a state in which the cover frame 40 is not attached to the developing frame 30.

[0040] The developing frame 30 has a developing chamber 31 and an agitating chamber 32 partitioned from the developing chamber 31 by a partition wall 38. The partition wall 38 is made of resin, and may be formed separately from the developing frame 30, or may be formed integrally with the developing frame 30.

[0041] The developing frame 30 has a sleeve support portion 42 for supporting bearings 71 provided at both ends of the developing sleeve 70, thereby rotatably supporting the developing sleeve 70. The developing frame 30 also has a blade attachment portion 41 formed integrally with the sleeve support portion 42, for attaching the doctor blade 36. Figure 5 shows a hypothetical state in which the doctor blade 36 is lifted off the blade attachment portion 41.

[0042] In the first embodiment, with the doctor blade 36 attached to the blade attachment part 41, the adhesive A applied to the blade attachment surface 41s of the blade attachment part 41 hardens, thereby fixing the doctor blade 36 to the blade attachment part 41. Details of the method of fixing the doctor blade 36 to the blade attachment part 41 will be described later with reference to FIG. 9 and subsequent figures.

[0043] (Plastic doctor blade) As the width of the sheet S on which an image is to be formed increases, for example to A3 size, the area of ​​the coat amount control surface corresponding to the maximum image area that can be formed on the surface of the photosensitive drum 1 becomes larger, and therefore the longitudinal length of the doctor blade becomes larger.

[0044] When a doctor blade having a large longitudinal length is molded from a resin, it is difficult to guarantee the straightness of the coating amount control surface of the resin doctor blade molded from the resin. This is because when a doctor blade having a large longitudinal length is molded from a resin, the rate at which the thermally expanded resin thermally contracts is likely to vary. The straightness of the coating amount control surface is expressed by the absolute value of the difference between the maximum and minimum values ​​of the outer shape of the coating amount control surface when a predetermined location on the coating amount control surface in the longitudinal direction of the coating amount control surface is used as a reference. For example, the center of the coating amount control surface in the longitudinal direction of the coating amount control surface is set as the origin of an orthogonal coordinate system, a predetermined straight line passing through the origin is set as the X-axis, and a straight line drawn from the origin at a right angle to the X-axis is set as the Y-axis. In this orthogonal coordinate system, the straightness of the coating amount control surface is expressed by the absolute value of the difference between the maximum and minimum values ​​of the Y-coordinate of the outer shape of the coating amount control surface.

[0045] For example, if a resin doctor blade whose longitudinal length corresponds to A3 size (hereinafter referred to as an A3 size resin doctor blade) is manufactured with the precision of a typical resin molded product, the straightness of the coat amount control surface is about 300 μm to 500 μm. Even if an A3 size resin doctor blade is manufactured with high precision using a high precision resin material, the straightness of the coat amount control surface is about 100 μm to 200 μm.

[0046] Therefore, in a resin doctor blade, the SB gap tends to vary in the longitudinal direction of the developer carrier due to the straightness of the coat amount control surface as the longitudinal length of the doctor blade increases. If the SB gap varies in the longitudinal direction of the developer carrier, there is a risk of unevenness in the amount of developer carried on the surface of the developer carrier in the longitudinal direction of the developer carrier.

[0047] Therefore, in the first embodiment, in order to suppress unevenness in the amount of developer carried on the surface of the developing sleeve 70 in the longitudinal direction of the developing sleeve 70, the SB gap G is set to be within a predetermined range over the longitudinal direction of the developing sleeve 70. Specifically, in the first embodiment, the tolerance of the SB gap G (i.e., the tolerance of the SB gap G with respect to the target value) is set to ±10% or less, and the SB gap G is set to be within a predetermined range over the longitudinal direction of the developing sleeve 70.

[0048] In the first embodiment, the method described below is used to determine whether the SB gap G is within a predetermined range over the longitudinal direction of the developing sleeve 70. Details of the measurement method (calculation method) of the SB gap G will be described later with reference to FIG.

[0049] First, the area corresponding to the maximum image area of ​​the doctor blade 36 is divided into four or more equal intervals, and the SB gap G is measured at five or more points at each divided portion of the doctor blade 36 (including both ends and the center of the area corresponding to the maximum image area of ​​the doctor blade 36). Then, the maximum value of the SB gap G, the minimum value of the SB gap G, and the median value of the SB gap G are extracted from the sample of measurement values ​​of the SB gap G measured at five or more points. At this time, it is sufficient that the absolute value of the difference between the maximum value of the SB gap G and the median value of the SB gap G is 10% or less of the median value of the SB gap G, and the absolute value of the difference between the minimum value of the SB gap G and the median value of the SB gap G is 10% or less of the median value of the SB gap G. In this case, it is satisfied that the tolerance of the SB gap G is ±10% or less, and that the SB gap G is within a predetermined range over the longitudinal direction of the developing sleeve 70.

[0050] For example, if the median value of the SB gap G is 300 μm from a sample of measurement values ​​of the SB gap G measured at five or more locations, the maximum value of the SB gap G may be 330 μm or less, and the minimum value of the SB gap G may be 270 μm or more. That is, in this case, the adjustment value of the SB gap G is 300 μm ± 30 μm, which means that the tolerance of the SB gap G is allowed up to 60 μm. For this reason, even if an A3-size resin doctor blade is manufactured with the precision of a general resin molded product, or even if it is manufactured with high precision using a high-precision resin material, the accuracy of the straightness of the coat amount control surface alone will exceed the allowable range of the tolerance of the SB gap G.

[0051] Therefore, in a developing device equipped with a resin doctor blade, it is desired that the SB gap G is within a predetermined range in the longitudinal direction of the developer carrier when the doctor blade is fixed to the attachment portion of the developing frame, regardless of the straightness of the coat amount control surface. In the first embodiment, by adopting the configuration described below, even if a resin doctor blade with low accuracy of the straightness of the coat amount control surface is used, the gap between the developer carrier and the doctor blade is within a predetermined range in the longitudinal direction of the developer carrier when the doctor blade is fixed to the attachment portion of the developing frame. Details are described below.

[0052] First, the configuration of the doctor blade 36 (single unit) will be described with reference to the perspective view of FIG.

[0053] During the image forming operation (developing operation), developer pressure (hereinafter referred to as developer pressure) generated from the flow of developer is applied to the doctor blade 36. The smaller the rigidity of the doctor blade 36, the more likely the doctor blade 36 is to deform and the more likely the size of the SB gap G is to vary when the developer pressure is applied to the doctor blade 36 during the image forming operation (developing operation). During the image forming operation (developing operation), the developer pressure is applied in the short-side direction of the doctor blade 36 (the direction of the arrow M in FIG. 6). Therefore, in order to suppress the variation in the size of the SB gap G during the image forming operation (developing operation), it is desirable to make the doctor blade 36 resistant to deformation in the short-side direction by increasing the rigidity of the doctor blade 36 in the short-side direction.

[0054] As shown in FIG. 6, in the first embodiment, the doctor blade 36 is plate-shaped from the viewpoint of mass production and cost. Also, as shown in FIG. 6, in the first embodiment, the cross-sectional area of ​​the side surface 36t of the doctor blade 36 is made small, and further, the length t2 in the thickness direction of the doctor blade 36 is made smaller than the length t1 in the short direction of the doctor blade 36. As a result, the doctor blade 36 (single unit) is easily deformed in a direction (arrow M direction in FIG. 6) perpendicular to the longitudinal direction of the doctor blade 36 (arrow N direction in FIG. 6). Therefore, in the first embodiment, in order to correct the straightness of the coat amount control surface 36r, the doctor blade 36 is fixed to the blade attachment portion 41 of the developing frame 30 in a state where at least a part of the doctor blade 36 is bent in the arrow M direction in FIG. 6. The details of the method of fixing the doctor blade 36 to the blade attachment portion 41 of the developing frame 30 (hereinafter, referred to as the fixing method of the doctor blade 36) will be described later with reference to FIG. 9 and subsequent figures.

[0055] Next, the rigidity of the doctor blade 36 (single unit) will be described with reference to the schematic diagram of Fig. 7. The rigidity of the doctor blade 36 (single unit) is measured in a state where the doctor blade 36 is not fixed to the blade attachment portion 41 of the developing frame 30.

[0056] 7, a concentrated load F1 is applied in the short-side direction of the doctor blade 36 to a central portion 36z of the doctor blade 36 in the longitudinal direction of the doctor blade 36. At this time, the rigidity of the doctor blade 36 (single unit) is measured based on the amount of deflection of the doctor blade 36 in the short-side direction of the doctor blade 36 at the central portion 36z of the doctor blade 36.

[0057] For example, assume that a concentrated load F1 of 300 gf is applied in the short-side direction of the doctor blade 36 to a central portion 36z of the doctor blade 36 in the longitudinal direction of the doctor blade 36. At this time, the deflection amount in the short-side direction of the doctor blade 36 at the central portion 36z of the doctor blade 36 is 700 μm or more. At this time, the deformation amount of the central portion 36z of the doctor blade 36 on the cross section is 5 μm or less.

[0058] Next, the rigidity of the developing frame 30 (single unit) will be described with reference to the schematic diagram of Fig. 8. The rigidity of the developing frame 30 (single unit) is measured in a state where the doctor blade 36 is not fixed to the blade attachment portion 41 of the developing frame 30.

[0059] 8, a concentrated load F1 is applied in the short-side direction of the blade mounting portion 41 to a central portion 41z of the blade mounting portion 41 in the longitudinal direction of the blade mounting portion 41. At this time, the rigidity of the developing frame 30 (single unit) is measured based on the amount of bending of the central portion 41z of the blade mounting portion 41 in the short-side direction of the blade mounting portion 41.

[0060] For example, assume that a concentrated load F1 of 300 gf is applied in the short-side direction of the blade mounting portion 41 to a central portion 41z of the blade mounting portion 41 in the longitudinal direction of the blade mounting portion 41. At this time, the amount of deflection of the blade mounting portion 41 in the short-side direction at the central portion 41z of the blade mounting portion 41 is 60 μm or less.

[0061] Assume that a concentrated load F1 of the same magnitude is applied to the center 36z of the doctor blade 36 and the center 41z of the blade mounting portion 41 of the developing frame 30. At this time, the amount of bending of the center 36z of the doctor blade 36 is 10 times or more larger than the amount of bending of the center 41z of the blade mounting portion 41. Therefore, the rigidity of the developing frame 30 (single unit) is 10 times or more larger than the rigidity of the doctor blade 36 (single unit). Therefore, in a state in which the doctor blade 36 is attached to the blade mounting portion 41 of the developing frame 30 and fixed to the blade mounting portion 41 of the developing frame 30, the rigidity of the developing frame 30 becomes dominant over the rigidity of the doctor blade 36.

[0062] In addition, the rigidity of the developing frame 30 (single unit) is greater than the rigidity of the cover frame 40 (single unit). Therefore, in a state in which the cover frame 40 is attached to the developing frame 30 and fixed to the developing frame 30, the rigidity of the developing frame 30 becomes dominant over the rigidity of the cover frame 40.

[0063] (How to fix a plastic doctor blade) 9 to 14, the steps of the method for fixing the doctor blade 36 will be described below. An external device (hereinafter, simply referred to as device 100) performs the steps of the method for fixing the doctor blade 36 described below.

[0064] First, the device 100 detects the outer shape of the coat amount control surface 36r of the doctor blade 36. Next, the device 100 recognizes the straightness of the coat amount control surface 36r with respect to the outer shape of the coat amount control surface 36r in the longitudinal direction of the coat amount control surface 36r, based on the center of the coat amount control surface 36r (the tip 36e3 of the doctor blade 36). In the process of the fixing method of the doctor blade 36, a resin doctor blade corresponding to A3 size manufactured with the accuracy of a general resin molded product is used. Therefore, the device 100 recognizes that the straightness of the coat amount control surface 36r is about 300 μm to 500 μm. Then, the device 100 bends at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36 by the force applied to the doctor blade 36. Then, the device 100 corrects the straightness of the coat amount control surface 36r to 50 μm or less (hereinafter referred to as the bending process).

[0065] Next, the device 100 determines a position for fixing the doctor blade 36, at least a part of which has been deflected in the deflecting step, to the blade attachment portion 41 of the developing frame 30 so as to set the SB gap G within a predetermined range (hereinafter referred to as a positioning step). Next, with the doctor blade 36 in a state in which the part of the area corresponding to the maximum image area is deflected, the device 100 fixes the part of the area corresponding to the maximum image area of ​​the doctor blade 36 at the predetermined position of the blade attachment portion 41 determined in the positioning step (hereinafter referred to as a fixing step).

[0066] The device 100 has a stand 103 for placing the doctor blade 36 (single unit). The device 100 also has five fingers 101 (101p1 to 101p5) for gripping the gripping portions 37 (37p1 to 37p5) provided at five locations within an area corresponding to the maximum image area of ​​the doctor blade 36. Each of the fingers 101 (101p1 to 101p5) is independently movable in the direction J in Fig. 9, and can move forward and backward relative to the direction J in Fig. 9.

[0067] The device 100 also has five cameras 102 (102p1-102p5) for measuring the positions of five tips 36e (36e1-36e5) included in the coat amount control surface 36r of the doctor blade 36. The cameras 102 (102p1-102p5) are arranged in a direction (the direction of arrow F in FIG. 9) toward the tips 36e (36e1-36e5) of the doctor blade 36. The cameras 102 (102p1-102p5) measure the positions of the tips 36e (36e1-36e5) of the doctor blade 36 to detect the outline of the coat amount control surface 36r of the doctor blade 36. Next, the device 100 recognizes the straightness of the coat amount control surface 36r with respect to the outer shape of the coat amount control surface 36r in the longitudinal direction of the coat amount control surface 36r, using the center of the coat amount control surface 36r (the tip 36e3 of the doctor blade 36) as a reference. Note that, although an example in which the position of the tip 36e (36e1 to 36e5) of the doctor blade 36 is measured by the camera 102 (102p1 to 102p5) will be described below, a modified example in which the position is measured by a non-contact sensor may also be used.

[0068] The doctor blade 36 is manufactured with the precision of a typical resin molded product. As described above, when a resin doctor blade for A3 size is manufactured with the precision of a typical resin molded product, the straightness of the coat amount control surface is about 300 μm to 500 μm. Assume that the doctor blade 36 is a resin doctor blade for A3 size manufactured with the precision of a typical resin molded product. In this case, when the doctor blade 36 is placed on the mounting table 103, the positions of the five tips 36e (36e1 to 36e5) of the doctor blade 36 are measured with the camera 102 (102p1 to 102p5), and there is a difference of about 300 μm to 500 μm. Meanwhile, as described above, in order to suppress unevenness in the amount of developer carried on the surface of the developing sleeve 70 in the longitudinal direction of the developing sleeve 70, the tolerance of the SB gap G is set to ±10% or less.

[0069] Therefore, in consideration of the allowable value of the tolerance of the SB gap G and the mounting accuracy of the doctor blade 36 to the developing frame 30, it is necessary to correct the straightness of the tip portions 36e1-36e5 of the doctor blade 36 (i.e., the straightness of the coat amount control surface 36r) to 50 μm or less. In consideration of the fact that the straightness accuracy of a metal doctor blade is 20 μm or less due to the secondary cutting process, it is more preferable to correct the straightness of the coat amount control surface 36r of the resin doctor blade 36 to 20 μm or less.

[0070] Next, a series of steps (deflection step, positioning step, and fixing step) of the method for fixing the doctor blade 36 will be described in detail below.

[0071] (1) Deflection process First, the details of the bending process will be described with reference to the schematic diagram of Fig. 9. The device 100 holds the doctor blade 36 by gripping the gripping portion 37 (37p1-37p5) of the doctor blade 36 with the fingers 101 (101p1-101p5). Next, the camera 102 (102p1-102p5) measures the position of the tip 36e (36e1-36e5) of the doctor blade 36 while the gripping portion 37 (37p1-37p5) of the doctor blade 36 is gripped with the fingers 101 (101p1-101p5). In this way, the device 100 detects the outline of the coat amount control surface 36r of the doctor blade 36. Next, the device 100 recognizes the straightness of the coat amount control surface 36r with respect to the outer shape of the coat amount control surface 36r in the longitudinal direction of the coat amount control surface 36r, using the center of the coat amount control surface 36r (the tip 36e3 of the doctor blade 36) as a reference.

[0072] Then, the device 100 moves each of the fingers 101 (101p1 to 101p5) holding the gripping portions 37 (37p1 to 37p5) of the doctor blade 36 in the direction J in FIG. 9 . As a result, the device 100 applies a force to the doctor blade 36 via the gripping portions 37 of the doctor blade 36 held by the fingers 101 to deflect at least a part of the area of ​​the doctor blade 36 corresponding to the maximum image area. Therefore, the gripping portions 37 of the doctor blade 36 serve as a force receiving portion for receiving the force applied from the device 100 to the doctor blade 36 to deflect at least a part of the area of ​​the doctor blade 36 corresponding to the maximum image area.

[0073] As shown in FIG. 10, the doctor blade 36 (single unit) has a shape in which the center of the coat amount control surface 36r of the doctor blade 36 is largely bent in the longitudinal direction of the doctor blade 36. Therefore, it is necessary to correct the straightness of the coat amount control surface 36r of the doctor blade 36 by reducing the difference in the position of the tip 36e (36e1 to 36e5) of the doctor blade 36. Therefore, based on the result of measuring the position of the tip 36e (36e1 to 36e5) of the doctor blade 36 (the detected outer shape of the coat amount control surface 36r), the difference in the position of the tip 36e (36e1 to 36e5) of the doctor blade 36 is reduced. For this purpose, the device 100 applies a force (also called a straightness correction force) to the doctor blade 36 for bending at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36, thereby correcting the straightness of the coat amount control surface 36r to 50 μm or less.

[0074] Next, the device 100 grips the gripping portions 37 (37p1 to 37p5) of the doctor blade 36 placed on the stand 103 with the fingers 101 (101p1 to 101p5). Then, while the fingers 101 (101p1 to 101p5) grip the gripping portions 37 (37p1 to 37p5) of the doctor blade 36, the device 100 moves each of the fingers 101 forward or backward independently in the direction of arrow J in Fig. 9. At this time, the device 100 applies a force to the doctor blade 36 via the gripping portions 37 of the doctor blade 36 to bend at least a part of the area of ​​the doctor blade 36 corresponding to the maximum image area.

[0075] In the example of Fig. 10, the device 100 applies a straightness correction force to the doctor blade 36 so that the outer shapes of the tip portions 36e1 and 36e5 of the doctor blade 36 are aligned with the reference, and the straightness correction force is applied to the doctor blade 36 so that the outer shapes of the tip portions 36e2, 36e3, and 36e4 are aligned with the reference. In the example of Fig. 10, the doctor blade 36 receives a force from the outside through three of the five gripping portions 37 (37p2 to 37p4) for bending at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36. Then, due to the force received by the doctor blade 36 through the three gripping portions 37 (37p2 to 37p4), a straightness correction force for correcting the straightness of the coat amount control surface 36r is applied to the tip portions 36e2 to 36e4 of the doctor blade 36 in the direction of arrow I in Fig. 10. At this time, a straightness correction force is applied to the coat amount control surface 36r, and at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36 is bent, thereby correcting the straightness of the coat amount control surface 36r of the doctor blade 36. In the example of Fig. 10, the shape of the coat amount control surface 36r of the doctor blade 36 is corrected from coat amount control surface 36r1 to coat amount control surface 36r2.

[0076] As a result, the straightness of the coat amount control surface 36r of the doctor blade 36 can be corrected to 50 μm or less. In the example of FIG. 10, the reference when the device 100 adjusts the outer shape of the tip 36e of the doctor blade 36 is the outer shape of the tips 36e1 and 36e5 of the doctor blade 36, but the reference may be the tip 36e3 (i.e., the center of the coat amount control surface 36r). In this modification, the device 100 applies a straightness correction force to the doctor blade 36 so that the outer shape of the tip 36e3 of the doctor blade 36 is adjusted to the reference.

[0077] In the first embodiment, in consideration of a realistic mass production process, the set value of the straightness correction of the coating amount control surface 36r of the doctor blade 36 is set to about 20 μm to 50 μm, and the magnitude of the straightness correction force applied to the tip 36e of the doctor blade 36 is set to about 500 g. In general, the smaller the magnitude of the straightness correction force applied to the tip 36e of the doctor blade 36, the cheaper and more compact the device 100 can be. However, if the magnitude of the straightness correction force applied to the tip 36e of the doctor blade 36 is too small compared to the rigidity of the doctor blade 36, it becomes impossible to correct the straightness of the coating amount control surface 36r of the doctor blade 36. Therefore, the magnitude of the straightness correction force applied to the tip 36e of the doctor blade 36 is set based on the rigidity of the doctor blade 36.

[0078] In the example of FIG. 9, the gripping portions 37 are provided at five positions on the doctor blade 36, but the number and positions of the gripping portions 37 on the doctor blade 36 are not limited to this, as long as the straightness correction force can be applied to the coating amount control surface 36r. In addition, in the example of FIG. 9, the gripping portions 37 of the doctor blade 36 are convex, but the shape of the gripping portions 37 is not limited to this. As described above, the finger 101 grips the gripping portions 37 of the doctor blade 36 so that the device 100 applies a force (straightness correction force) to the doctor blade 36 for bending at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36. Therefore, as long as the finger 101 can grip the gripping portions 37, the shape of the gripping portions 37 may be, for example, a concave shape, a groove shape, a notch shape, or a flat shape, other than a convex shape, or a combination of these shapes. In the drawings in this specification in which the doctor blade 36 is shown, the gripping portion 37 of the doctor blade 36 is omitted, except for Figs. 9 to 12.

[0079] (2) Positioning process Next, details of the positioning step will be described with reference to the schematic views of Figures 11 and 12. As shown in Figures 11 and 12, the positioning step is performed in a state in which the developing sleeve 70 is supported by the sleeve supporting portion 42 of the developing frame 30.

[0080] The fingers 101 (101p1 to 101p5) move the doctor blade 36 from the stand 103 to the blade attachment part 41 while holding the doctor blade 36 in the state bent in the bending process (i.e., the state in which the straightness of the coating amount control surface 36r has been corrected). The amount and direction of movement of the fingers 101 (101p1 to 101p5) are preset in a program. The fingers 101 (101p1 to 101p5) are driven by an actuator and operate according to a preset program.

[0081] Then, the device 100 moves the doctor blade 36 in the bent state to the blade attachment portion 41 of the developing frame 30 while the fingers 101 (101p1 to 101p5) are still gripping the gripping portion 37 of the doctor blade 36 in the bending process. Next, the device 100 attaches the doctor blade 36 in the bent state to the blade attachment portion 41. At this time, the doctor blade 36 in the bent state comes into contact with (also referred to as a hit state) the blade attachment surface 41s (see FIGS. 4 and 5) of the developing frame 30.

[0082] FIG. 11 shows the doctor blade 36 in a state where it has been bent in the bending process and has landed on the blade attachment surface 41s while the gripping portions 37 (37p1 to 37p5) of the doctor blade 36 are gripped by the fingers 101 (101p1 to 101p5).

[0083] As described above, in order to suppress unevenness in the amount of developer carried on the surface of the developing sleeve 70 in the longitudinal direction of the developing sleeve 70, the tolerance range of the SB gap G (i.e., the range allowed as the tolerance for the target value of the SB gap G) is set to a range of about 60 μm. Since the tolerance range of the SB gap G is strict, the SB gap G is unlikely to fall within the adjustment range of the SB gap G that takes into account the tolerance range of the SB gap G (i.e., the adjustment range of the SB gap G includes the target value of the SB gap G) by simply landing the doctor blade 36 on the blade mounting surface 41s of the developing frame 30. Therefore, it is necessary to adjust the SB gap G so that it falls within the adjustment range of the SB gap G by determining the position at which the doctor blade 36 is fixed relative to the blade mounting surface 41s of the developing frame 30 so that the SB gap G falls within the tolerance range.

[0084] The device 100 has five cameras 104 (104p1 to 104p5) for measuring the positions of the five tips 36e (36e1 to 36e5) of the doctor blade 36 when the doctor blade 36 is landed on the blade mounting surface 41s of the developing frame 30 by the finger 101. The cameras 104 (104p1 to 104p5) are arranged in a direction toward the tips 36e (36e1 to 36e5) of the doctor blade 36 (the direction of the arrow F in FIG. 11), and can measure the positions of the tips 36e (36e1 to 36e5) of the doctor blade 36. In the first embodiment, an example in which the positions of the tips 36e (36e1 to 36e5) of the doctor blade 36 are measured by the cameras 104 (104p1 to 104p5) will be described below, but a modified example in which the positions are measured by a non-contact sensor may be used.

[0085] Here, a method for measuring (calculating) the size of the SB gap G will be described. The size of the SB gap G is measured in a state where the developing sleeve 70 is supported by the sleeve support portion 42 of the developing frame 30, the doctor blade 36 is attached to the blade attachment portion 41 of the developing frame 30, and the cover frame 40 is fixed to the developing frame 30. In measuring the size of the SB gap G, a light source (e.g., an LED array or a light guide) is inserted into the developing chamber 31 along the longitudinal direction of the developing chamber 31. The light source inserted into the developing chamber 31 irradiates light from within the developing chamber 31 toward the SB gap G. Then, the camera 104 (104p1 to 104p5) captures an image of the light beam emitted from the SB gap G to the outside of the developing frame 30. At this time, the cameras 104 (104p1-104p5) read the positions 70a (70a1-70a5) on the surface of the developing sleeve 70 where the developing sleeve 70 is closest to the doctor blade 36, and the tip 36e (36e1-36e5) of the doctor blade 36. Next, the device 100 converts pixel values ​​into distances from the image data generated by reading with the cameras 104 (104p1-104p5), and calculates the size of the SB gap G. If the calculated size of the SB gap G is not within a predetermined range, the device 100 adjusts the SB gap G.

[0086] Here, the details of the method of adjusting the SB gap G will be described with reference to the schematic diagram of Fig. 12. The device 100 moves the fingers 101 (101p1-101p5) of the doctor blade 36 in the direction of the arrow K shown in Fig. 12 while gripping the gripping portions 37 (37p1-37p5) of the doctor blade 36 with the fingers 101. The direction of the arrow K in Fig. 12 is the direction in which the relative position of the doctor blade 36 with respect to the developing sleeve 70 supported by the sleeve support portion 42 of the developing frame 30 is adjusted (i.e., the direction that defines the SB gap G). The direction of the arrow K in Fig. 12 also indicates the direction in which the doctor blade 36 approaches or moves away from the developing sleeve 70 supported by the sleeve support portion 42 of the developing frame 30. As a result, the relative position of the tip 36e (36e1 to 36e5) of the doctor blade 36 with respect to the position 70a (70a1 to 70a5) on the surface of the developing sleeve 70 where the developing sleeve 70 is closest to the doctor blade 36 is adjusted.

[0087] For example, assume that the SB gap G calculated at the initial position where the doctor blade 36 lands on the blade mounting surface 41s of the developing frame 30 is 350 μm. Meanwhile, assume that the adjustment range of the SB gap G is 300 μm±30 ​​μm, and the tolerance of the SB gap G is allowed up to 60 μm. In this case, at the initial position where the doctor blade 36 lands on the blade mounting surface 41s of the developing frame 30, the SB gap G is 50 μm larger than the nominal value of 300 μm. Therefore, while gripping the gripping portion 37 of the doctor blade 36, the finger 101 translates the doctor blade 36 in the direction of the arrow K shown in FIG. 12, in a direction that brings the doctor blade 36 closer to the surface of the developing sleeve 70 by 50 μm.

[0088] Then, the camera 104 reads the position 70a (70a1-70a5) closest to the doctor blade 36 translated by the finger 101, and the tip 36e (36e1-36e5) of the doctor blade 36 translated by the finger 101. Next, the device 100 recalculates the SB gap G for the doctor blade 36 translated by the finger 101.

[0089] When the apparatus 100 determines that the calculated size of the SB gap G is within the range of the adjustment value of the SB gap G (300 μm±30 ​​μm), it ends the adjustment of the SB gap G described above. On the other hand, when the apparatus 100 determines that the calculated size of the SB gap G is not within the adjustment range of the SB gap G (300 μm±30 ​​μm), it repeats the adjustment of the SB gap G described above until it is within the adjustment range of the SB gap G (300 μm±30 ​​μm). In this way, by fixing the doctor blade 36 to the blade attachment portion 41 of the developing frame 30 with the straightness of the coat amount control surface 36r corrected to 50 μm or less, it is possible to bring the size of the SB gap G within the adjustment range of the SB gap G.

[0090] Here, a more preferable embodiment for adjusting the SB gap G with higher accuracy will be described with reference to the schematic diagrams of Figures 13 and 14. In this embodiment, the SB gap G is adjusted with higher accuracy by taking into consideration not only the straightness of the coat amount control surface 36r of the doctor blade 36 but also the straightness of the surface of the developing sleeve 70.

[0091] Since the sleeve tube constituting the outer shell of the developing sleeve 70 is made of metal, the straightness of the surface of the developing sleeve 70 can be made highly accurate, such as ±15 μm or less, by subjecting the sleeve tube to secondary cutting processing. However, the straightness of ±15 μm of the developing sleeve 70 means that the outer diameter of the developing sleeve 70 appears to vary by ±15 μm when the developing sleeve 70 is rotating in actual use. In order to minimize the effect on the SB gap G caused by the accuracy of the straightness of the coat amount control surface 36r of the doctor blade 36 when the developing sleeve 70 is rotating, it is effective to measure the SB gap G while rotating the developing sleeve 70.

[0092] Fig. 13 shows the position of the tip 36e of the doctor blade 36 when the developing sleeve 70 is stopped. Fig. 13(A) shows a state in which the SB gap G has been adjusted with the developing sleeve 70 stopped at a position far from the doctor blade 36. Meanwhile, Fig. 13(B) shows a state in which the SB gap G has been adjusted with the developing sleeve 70 stopped at a position close to the doctor blade 36. Fig. 14 shows the position of the tip 36e of the doctor blade 36 when the developing sleeve 70 is rotating.

[0093] As shown in Figs. 13A and 13B, the size of the SB gap G is the same between Figs. 13A and 13B, but the position of the tip 36e of the doctor blade 36 is different between Figs. 13A and 13B. In addition, there is a difference between the phase of the developing sleeve 70 when the developing sleeve 70 is stopped at a position far from the doctor blade 36 and the phase of the developing sleeve 70 when the developing sleeve 70 is stopped at a position close to the doctor blade 36. As a result, even if the developing sleeve 70 and the doctor blade 36 with the same accuracy are used and adjusted with the same adjustment value of the SB gap G, the doctor blade 36 will be fixed to the blade attachment portion 41 of the developing frame 30 with the tip 36e in a different position. This means that manufacturing variations are allowed in the manufacturing of the developing device 3. Therefore, the SB gap G is adjusted while rotating the developing sleeve 70, thereby reducing the manufacturing variations.

[0094] When the developing sleeve 70 is rotated, due to the straightness of the surface of the developing sleeve 70, a runout, which is a movement of the outer diameter line of the developing sleeve 70 (hereinafter, referred to as the runout of the outer diameter of the developing sleeve 70), occurs. As shown in FIG. 14, the outer diameter line of the developing sleeve 70 is seen to move back and forth between the outer diameter line 73L1 of the developing sleeve 70 and the outer diameter line 73L2 of the developing sleeve 70, with the center line 73L0 of the runout of the outer diameter of the developing sleeve 70 as the center. Therefore, by measuring the runout of the outer diameter of the developing sleeve 70, the center of the runout of the outer diameter of the developing sleeve 70 can be detected. Therefore, it is sufficient to detect the center line 73L0 of the runout of the outer diameter of the developing sleeve 70 and measure the size of the SB gap G from the center line 73L0 of the runout of the outer diameter of the developing sleeve 70. This makes it possible to suppress the variation in the position of the tip portion 36e of the doctor blade 36 caused by the difference between the phase of the developing sleeve 70 when it is stopped at a position far from the doctor blade 36 and the phase of the developing sleeve 70 when it is stopped at a position close to the doctor blade 36.

[0095] Therefore, by using the same developing sleeve 70 and the same doctor blade 36, and by using the same adjustment value of the SB gap G while rotating the developing sleeve 70, it becomes possible to reproduce the position of the tip 36e of the doctor blade 36 in the same position. This makes it possible to reduce variations in manufacturing.

[0096] As described above, the straightness of the surface of the developing sleeve 70 is within ±15 μm, but in order to adjust the SB gap with higher precision, it is necessary to consider not only the straightness of the coating amount control surface 36r of the doctor blade 36 but also the straightness of the surface of the developing sleeve 70. Therefore, in the positioning process, the finger 101 performs the following operation with the doctor blade 36 landed on the blade attachment surface 41s while translating the doctor blade 36 in a direction to bring the doctor blade 36 closer to the surface of the developing sleeve 70.

[0097] Before landing the doctor blade 36 on the blade attachment surface 41s, the device 100 applies a straightness correction force to the doctor blade 36 via the gripping portion 37 of the doctor blade 36 to correct the straightness of the coat amount control surface 36r. That is, before landing the doctor blade 36 on the blade attachment surface 41s, the device 100 corrects the straightness of the coat amount control surface 36r to 50 μm or less in advance. Then, the device 100 lands the doctor blade 36, with the straightness of the coat amount control surface 36r corrected to 50 μm or less, on the blade attachment surface 41s.

[0098] Next, the device 100 applies an adjustment force to the doctor blade 36 via the gripping portion 37 of the doctor blade 36 to adjust the relative position of the coat amount control surface 36r of the doctor blade 36 with respect to the developing sleeve 70 so that the SB gap G falls within a predetermined range (i.e., the adjustment range of the SB gap G) when the doctor blade 36 is fixed to the blade attachment portion 41. That is, the finger 101 bends at least a part of the area of ​​the doctor blade 36 corresponding to the maximum image area so that the SB gap G measured by the camera 104 falls within the adjustment range of the SB gap G when the doctor blade 36 lands on the blade attachment surface 41s. At this time, at least a part of the area of ​​the doctor blade 36 corresponding to the maximum image area is bent in a direction in which the doctor blade 36 attached to the blade attachment portion 41 approaches or moves away from the developing sleeve 70 supported by the sleeve support portion 42.

[0099] This makes it possible to adjust the SB gap G with higher accuracy, taking into consideration not only the straightness of the coat amount control surface 36r of the doctor blade 36 but also the straightness of the surface of the developing sleeve 70. It also becomes possible to adjust the relative position of the coat amount control surface 36r of the doctor blade 36 with respect to the developing sleeve 70 so that the tolerance of the SB gap G is 60 μm or less along the longitudinal direction of the developing sleeve 70. In this case, after the relative position of the coat amount control surface 36r with respect to the developing sleeve 70 is adjusted so that the tolerance of the SB gap G is 60 μm or less along the longitudinal direction of the developing sleeve 70, the doctor blade 36 is fixed to the blade attachment portion 41 by a fixing process described below.

[0100] Incidentally, when the straightness of the surface of the developing sleeve 70 is more precise (for example, ±5 μm or less), the SB gap G may be adjusted while taking into consideration the straightness of the coat amount control surface 36r, and it is not essential to take into consideration the straightness of the surface of the developing sleeve 70. Similarly, when the latitude of the SB gap G is large, the SB gap G is adjusted while taking into consideration the straightness of the coat amount control surface 36r of the doctor blade 36, but it is not essential to take into consideration the straightness of the surface of the developing sleeve 70.

[0101] (3) Fixing process Next, the details of the fixing step will be described with reference to the schematic diagram of Fig. 12. In the first embodiment, as shown in Fig. 12, the fixing step is performed in a state where the doctor blade 36, which has been bent in the bending step, is landed at a predetermined position of the blade attachment portion 41 of the developing frame 30 determined in the positioning step.

[0102] In the first embodiment, the device 100 applies adhesive A to the blade mounting surface 41s over substantially the entire area corresponding to the maximum image area before the doctor blade 36 lands on the blade mounting surface 41s of the developing frame 30. Then, the doctor blade 36 in the bending state in the bending process is adhered (fixed) to the blade mounting portion 41 over substantially the entire area corresponding to the maximum image area. At this time, the doctor blade 36 is adhered (fixed) to the blade mounting portion 41 with the straightness of the coat amount control surface 36r corrected to 50 μm or less.

[0103] That is, in the first embodiment, the area of ​​the doctor blade 36 that corresponds to the maximum image area and that is bent to correct the straightness of the coat amount control surface 36r is fixed to the blade attachment portion 41. This makes it possible to prevent the area of ​​the doctor blade 36 that corresponds to the maximum image area and that is bent to correct the straightness of the coat amount control surface 36r from returning from the bent state to its original state before bending.

[0104] On the other hand, depending on the shape of the blade attachment part 41, there may be an area on the blade attachment surface 41s where it is difficult for the device 100 to apply the adhesive A. In such a case, as long as the area that receives the force for bending at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36 is fixed to the blade attachment part 41 by the adhesive A, it is not necessary for the adhesive A to be applied to a part of the blade attachment surface 41s.

[0105] Thus, the adhesive A being applied over substantially the entire area of ​​the area corresponding to the maximum image area on the blade attachment surface 41s means that the following conditions are met: The adhesive A is applied over 95% or more of the area corresponding to the maximum image area in the longitudinal direction of the blade attachment surface 41s, including the area of ​​the doctor blade 36 that is bent to correct the straightness of the coat amount control surface 36r within the area corresponding to the maximum image area.

[0106] When selecting adhesive A, it is necessary that the adhesive A has an adhesive strength sufficient to prevent the doctor blade 36 from peeling off from the blade attachment surface 41s of the developing frame 30 during the image forming operation (developing operation). The load applied to the doctor blade 36 during the image forming operation (developing operation) is about 2 kgf in a drop test, and there is no problem if the doctor blade 36 does not peel off from the blade attachment surface 41s of the developing frame 30 under that load. For this reason, it is known that a general adhesive A can ensure sufficient adhesive strength, and from the viewpoint of ensuring mass productivity, the shorter the curing time of adhesive A, the better.

[0107] Next, a description will be given of the film thickness of the adhesive A applied to the blade mounting surface 41s of the developing frame 30. Since the doctor blade 36 and the blade mounting surface 41s of the developing frame 30 are joined using the adhesive A, the adhesive A is interposed between the doctor blade 36 and the blade mounting surface 41s of the developing frame 30. For this reason, it is necessary to take into consideration the film thickness of the adhesive A applied to the blade mounting surface 41s so that the adhesive A interposed between the doctor blade 36 and the blade mounting surface 41s of the developing frame 30 does not affect the size of the SB gap G.

[0108] Regarding the relationship between the film thickness of adhesive A and the magnitude of the breaking load of the portion bonded by adhesive A, the greater the amount of adhesive A, the greater the adhesive strength of adhesive A. As described above, the magnitude of the load applied to the doctor blade 36 during the image forming operation (developing operation) is about 2 kgf, and to allow for a margin, in the first embodiment, the strength required for the adhesive strength of adhesive A is set to 10 kgf or more. Therefore, in order to ensure that the adhesive strength of adhesive A is 10 kgf or more, the film thickness of adhesive A applied to the blade attachment surface 41s of the developing frame 30 should be set to 20 μm or more.

[0109] Next, the relationship between the thickness of the adhesive A applied and the magnitude of the dimensional fluctuation of the adhesive A in the thickness direction will be described. In general, the larger the film thickness of the adhesive A, the greater the dimensional fluctuation of the adhesive A in the thickness direction due to the shrinkage of the adhesive A when the adhesive A hardens. On the other hand, the magnitude of the dimensional fluctuation of the adhesive A in the thickness direction when the film thickness of the adhesive A is 150 μm is only about 8 μm larger than the magnitude of the dimensional fluctuation of the adhesive A in the thickness direction when the film thickness of the adhesive A is 30 μm. If the difference in the magnitude of the dimensional fluctuation of the adhesive A in the thickness direction is about 8 μm, it is at a level that can be ignored as the influence of the dimensional fluctuation in the direction perpendicular to the thickness direction of the adhesive A (i.e., the direction that defines the SB gap G). Therefore, the upper limit of the film thickness of the adhesive A applied to the blade attachment surface 41s of the developing frame 30 may be determined not by the influence of the shrinkage of the adhesive A, but by individual production requirements such as the curing time and cost of the adhesive A.

[0110] In the first embodiment, the adhesive A is applied to the blade mounting portion 41 side, but the adhesive A may be applied to the doctor blade 36 side or to both the blade mounting portion 41 side and the doctor blade 36 side. If the adhesive A is applied to the blade mounting portion 41 side prior to the start of the positioning step (more preferably, in parallel with the bending step), the total time required for the series of steps of the method for fixing the doctor blade 36 can be shortened. That is, in this example, this means a series of steps in which the adhesive A is applied to the blade mounting portion 41 of the developing frame 30 while correcting the straightness of the coat amount control surface 36r. Therefore, in the first embodiment, the following description will be given assuming that the step of applying the adhesive A to the blade mounting portion 41 of the developing frame 30 is performed prior to the start of the positioning step.

[0111] When the doctor blade 36 is fixed by the adhesive A, if the adhesive A hardens during the adjustment of the SB gap G for the doctor blade 36 that has landed on the blade attachment surface 41s in the positioning step, the SB gap G cannot be adjusted thereafter. Therefore, the adjustment of the SB gap G must be completed before the adhesive A hardens. The time it takes for the adhesive A to harden is determined depending on the material of the adhesive A and the amount of adhesive A applied. Therefore, the time it takes for the adhesive A to harden can be predicted to some extent. Therefore, the number of times that the SB gap G can be repeatedly adjusted before the adhesive A hardens is determined in advance from the time required for each adjustment of the SB gap G. Therefore, within the range of the number of times, the adhesive A has not yet hardened, so the SB gap G can be repeatedly adjusted.

[0112] If repeated adjustment of the SB gap G is prioritized over shortening the total time required for the series of steps of the method for fixing the doctor blade 36, a modified example in which the adhesive A is applied to the blade mounting portion 41 side after the positioning step is completed may be used. In this modified example, the device 100 stores in a memory of the device 100 information on the position at which the doctor blade 36 is fixed to the blade mounting surface 41s of the developing frame 30, which is determined by adjusting the SB gap G in the positioning step. Then, after the positioning step is completed, the device 100 performs a step of applying the adhesive A to the blade mounting portion 41 side of the developing frame 30. Then, after the adhesive A is applied to the blade mounting portion 41 side, the device 100 lands the doctor blade 36, which has been bent in the bending step, on the blade mounting surface 41s of the developing frame 30, based on the information on the fixing position of the doctor blade 36 stored in the memory. Then, after the doctor blade 36 in the bent state has landed on the blade attachment surface 41s, the device 100 may start the fixing step described above.

[0113] After completing the adjustment of the SB gap G, in order to achieve a desired adhesive strength between the doctor blade 36 and the blade attachment portion 41 of the developing frame 30, it is necessary to keep the doctor blade 36 in close contact with the blade attachment portion 41 until the adhesive A hardens. In order to bond the doctor blade 36 to the blade attachment portion 41 with sufficient adhesive strength, the degree of adhesion between the doctor blade 36 and the blade attachment portion 41 is important. This is because, if the gap between the doctor blade 36 and the blade attachment portion 41 is large, the adhesive strength will be weak even if the adhesive A is present in the gap.

[0114] Therefore, in order to bring the doctor blade 36 into close contact with the blade attachment portion 41, it is necessary to apply a certain load. Specifically, the device 100 applies a load to bring the doctor blade 36 into close contact with the blade attachment portion 41 by dropping a weight having a predetermined weight on the doctor blade 36 in a state where the doctor blade 36 is in contact with the blade attachment portion 41 while the doctor blade 36 is in contact with the blade attachment portion 41 under such load in order to obtain sufficient adhesive strength, the finger 101 must continue to hold the doctor blade 36 for a period of time until the adhesive A is sufficiently cured. For example, if the curing time of the adhesive A is 15 seconds, the load to bring the doctor blade 36 into close contact with the blade attachment portion 41 may be set to be applied for 20 seconds with a margin of error.

[0115] Then, after the doctor blade 36 has been attached to the blade attachment portion 41, the device 100 raises the weight to remove the load from the doctor blade 36. Then, the device 100 operates the fingers 101 (101p1 to 101p5) to separate the fingers 101 (101p1 to 101p5) from the doctor blade 36, and then moves the fingers 101 (101p1 to 101p5) to a preparation position for the next operation.

[0116] The above is the details of the steps of the fixing method of the doctor blade 36. In the above-described series of fixing methods, the device 100 preliminarily corrects the straightness of the coat amount control surface 36r to 50 μm or less before landing the doctor blade 36, whose coat amount control surface 36r has an accuracy of about 300 μm to 500 μm, on the blade mounting surface 41s. As a result, even if a resin doctor blade 36 having a low accuracy of straightness of the coat amount control surface 36r is used, the SB gap G can be set within the adjustment range of the SB gap G when the doctor blade 36 is fixed to the blade mounting part 41. In this example, the function for performing the bending process and the function for performing the positioning process are provided in separate devices 100. That is, the doctor blade 36 (single unit) is placed on the mounting table 103 of the device 100 for performing the bending process, which is a device different from the device 100 for performing the positioning process. The device 100 for performing the bending process applies a force to the doctor blade 36, with the doctor blade 36 (single) placed on a support table 103, to bend at least a portion of the area corresponding to the maximum image area of ​​the doctor blade 36.

[0117] On the other hand, a modified example in which a function for performing the bending process and a function for performing the positioning process are provided in one device 100 is also conceivable. In this modified example, the one device 100 does not correct the straightness of the coat amount control surface 36r to 50 μm or less before landing the doctor blade 36, whose accuracy of the coat amount control surface 36r is about 300 μm to 500 μm, on the blade attachment surface 41s. Instead, the one device 100 bends at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36 so that the SB gap G falls within the adjustment range of the SB gap G, during the time period from when the doctor blade 36 lands on the blade attachment surface 41s until the adhesive A hardens. That is, this modified example means a series of steps in which the doctor blade 36 is fixed to the blade attachment surface 41s while bending at least a part of the area corresponding to the maximum image area of ​​the doctor blade 36 so that the SB gap G falls within a predetermined range (i.e., the adjustment range of the SB gap G). As a result, even if a resin doctor blade 36 having a low straightness accuracy of the coat amount control surface 36r is used, when the doctor blade 36 is fixed to the blade attachment portion 41, the SB gap G can be within the adjustment range of the SB gap G.

[0118] However, as described above, when a doctor blade made of resin compatible with A3 size is manufactured with the accuracy of a general resin molded product, the straightness of the coat amount control surface is about 300 μm to 500 μm. For this reason, it is preferable that the device 100 corrects the straightness of the coat amount control surface 36r to 50 μm or less before the doctor blade 36 lands on the blade attachment surface 41s. This is because the SB gap G is adjusted in a state where the straightness of the coat amount control surface 36r is corrected to 50 μm or less, and the adjustment time is shorter than when the SB gap G is adjusted in a state where the straightness of the coat amount control surface 36r is about 300 μm to 500 μm. In other words, the time required for the process performed in a state where the doctor blade 36 lands on the blade attachment surface 41s (the adjustment time of the SB gap G) is shorter, so that the time until the adhesive A applied to the blade attachment surface 41s hardens can be set to be shorter. Furthermore, having the function for performing the bending process and the function for performing the positioning process in separate devices 100 is advantageous in terms of mass productivity, since the takt time can generally be shortened compared to having them in a single device 100.

[0119] Next, the deformation of the doctor blade 36 caused by the agent pressure generated by the flow of the developer acting on the doctor blade 36 during the image forming operation (developing operation) will be described with reference to the cross-sectional view of Fig. 15. Fig. 15 is a cross-sectional view of the developing device 3 taken along a cross section (cross section H in Fig. 2) perpendicular to the rotation axis of the developing sleeve 70. Fig. 15 also shows the configuration in the vicinity of the doctor blade 36 fixed to the blade attachment portion 41 of the developing frame 30 with adhesive A.

[0120] As shown in FIG. 15, the line connecting the closest position of the doctor blade 36 to the developing sleeve 70 on the coating amount control surface 36r and the rotation center of the developing sleeve 70 is taken as the X-axis. At this time, the doctor blade 36 is long in the X-axis direction, and the rigidity in the cross section in the X-axis direction is large. Also, as shown in FIG. 15, the ratio of the cross-sectional area T1 of the doctor blade 36 to the cross-sectional area T2 of the wall portion 30a of the developing frame 30 located in the vicinity of the developer guide portion 35 is small. As described above, in the first embodiment, the rigidity of the developing frame 30 (single unit) is set to be 10 times or more larger than the rigidity of the doctor blade 36 (single unit). Therefore, in a state in which the doctor blade 36 is fixed to the blade attachment portion 41 of the developing frame 30, the rigidity of the developing frame 30 becomes dominant with respect to the doctor blade 36. As a result, during image formation operation (development operation), the displacement amount (maximum deflection amount) of the coat amount control surface 36r of the doctor blade 36 when the doctor blade 36 is subjected to developer pressure becomes substantially equivalent to the displacement amount (maximum deflection amount) of the developing frame 30.

[0121] During the image forming operation (developing operation), the developer pumped up from the first conveying screw 33 passes through the developer guide portion 35 and is conveyed to the surface of the developing sleeve 70. After that, even when the doctor blade 36 determines the layer thickness of the developer to the size of the SB gap G, the doctor blade 36 receives developer pressure from various directions. As shown in FIG. 15, when the direction perpendicular to the X-axis direction (the direction that determines the SB gap G) is the Y-axis direction, the developer pressure in the Y-axis direction is perpendicular to the blade mounting surface 41s of the developing frame 30. That is, the developer pressure in the Y-axis direction is a force in a direction that peels the doctor blade 36 off the blade mounting surface 41s. Therefore, the bonding force of the adhesive A needs to be sufficiently large relative to the agent pressure in the Y-axis direction. Therefore, in the first embodiment, the adhesive area and coating thickness of the adhesive A on the blade mounting surface 41s are optimized in consideration of the force that peels the doctor blade 36 off the blade mounting surface 41s due to the agent pressure and the adhesive force of the adhesive A. Furthermore, in the first embodiment, the cross-sectional area T2 of the wall portion 30a of the developing frame 30 is made sufficiently large relative to the developer pressure in the Y-axis direction received by the developer guide portion 35, so that deformation of the doctor blade 36 due to the developer pressure during the image formation operation (developing operation) can be suppressed.

[0122] Next, the deformation of the doctor blade 36 caused by the temperature change due to the heat generated during the image forming operation (developing operation) will be described with reference to the perspective view of Fig. 16. Examples of heat generated during the developing operation include heat generated when the rotating shaft of the developing sleeve 70 and the bearing 71 rotate, heat generated when the rotating shaft 33a of the first conveying screw 33 and the bearing member rotate, and heat generated when the developer passes through the SB gap G. These heats generated during the image forming operation (developing operation) change the temperature around the developing device 3, and the temperatures of the doctor blade 36, the developing frame 30, and the cover frame 40 also change.

[0123] On the other hand, when the linear expansion coefficient α1 of the resin constituting the doctor blade 36 is different from the linear expansion coefficient α2 of the resin constituting the developing frame 30, the amount of deformation due to temperature change will differ due to the difference in linear expansion coefficients. As described above, in the first embodiment, the doctor blade 36 is fixed to the blade attachment portion 41 of the developing frame 30 by the adhesive A over substantially the entire area corresponding to the maximum image area. In addition, when there is a large difference between the linear thermal expansion coefficient α2 of the resin constituting the developing frame 30 and the linear thermal expansion coefficient α1 of the resin constituting the doctor blade 36, the following problem occurs when a temperature change occurs. That is, when a temperature change occurs, the amount of deformation (amount of expansion and contraction) of the doctor blade 36 due to the temperature change will differ from the amount of deformation (amount of expansion and contraction) of the developing frame 30 due to the temperature change.

[0124] For example, suppose that the doctor blade 36 is fixed to the blade attachment surface 41s at least in a first region, a second region, and a third region (e.g., three or more regions including both ends and a center of the region corresponding to the maximum image region of the doctor blade 36) in the region corresponding to the maximum image region of the doctor blade 36. In this case, since the amount of thermal expansion differs between the center and both ends of the doctor blade 36, the doctor blade 36 may be significantly deflected and may be significantly warped. As a result, even if the SB gap G is adjusted with high accuracy when determining the position for attaching the doctor blade 36 to the blade attachment surface 41s of the developing frame 30, the size of the SB gap G will vary due to temperature changes during the image forming operation (developing operation).

[0125] In the first embodiment, the doctor blade 36 is fixed to the blade mounting surface 41s over almost the entire area corresponding to the maximum image area, so it is necessary to suppress fluctuations in the size of the SB gap G caused by temperature changes during the image formation operation (development operation).

[0126] As shown in FIG. 16, the amount of extension of the doctor blade 36 due to temperature change is H [μm], and the amount of extension of the blade mounting surface 41s of the blade mounting portion 41 of the developing frame 30 due to temperature change is I [μm]. In addition, it is assumed that the linear expansion coefficient α1 of the resin constituting the doctor blade 36 is different from the linear expansion coefficient α2 of the resin constituting the developing frame 30. In this case, the difference in the linear expansion coefficients causes the amounts of deformation of the developing frame 30 and the doctor blade 36 due to temperature change to differ, and in order to compensate for the difference between H [μm] and I [μm], the doctor blade 36 deforms in the direction of the arrow J in FIG. 16. The deformation of the doctor blade 36 in the direction of the arrow J in FIG. 16 is hereinafter referred to as the deformation in the warping direction of the doctor blade 36. The deformation in the warping direction of the doctor blade 36 leads to a change in the size of the SB gap G. In order to suppress fluctuations in the size of the SB gap G caused by heat, the linear expansion coefficient α2 of the resin constituting the sleeve support portion 42 and the blade mounting portion 41 of the developing frame 30 (single unit) and the linear expansion coefficient α1 of the resin constituting the doctor blade 36 (single unit) are each related.

[0127] Hereinafter, the difference between the linear expansion coefficient α1 of the resin constituting the doctor blade 36 and the linear expansion coefficient α2 of the resin constituting the developing frame 30 having the sleeve support portion 42 and the blade attachment portion 41 will be referred to as the linear expansion coefficient difference α2-α1. The change in the maximum deflection amount of the doctor blade 36 due to this linear expansion coefficient difference α2-α1 will be described with reference to Table 1. With the doctor blade 36 fixed to the blade attachment portion 41 of the developing frame 30 over almost the entire area corresponding to the maximum image area, the maximum deflection amount of the doctor blade 36 was measured when a temperature change from room temperature (23°C) to a high temperature (40°C) was applied.

[0128] The linear expansion coefficient of the resin constituting the developing frame 30 having the sleeve support portion 42 and the blade attachment portion 41 is α2 [m / °C], and the linear expansion coefficient of the resin constituting the doctor blade 36 is α1 [m / °C]. The parameter of the linear expansion coefficient difference α2-α1 was changed, and the maximum deflection amount of the doctor blade 36 was measured. The results are shown in Table 1.

[0129] As described above, in order to suppress unevenness in the amount of developer carried on the surface of the developing sleeve 70 in the longitudinal direction of the developing sleeve 70, the fluctuation amount of the SB gap G caused by heat generally needs to be suppressed to ±20 μm or less. Therefore, in Table 1, when the absolute value of the maximum deflection amount of the doctor blade 36 is 20 μm or less, the maximum deflection amount is indicated as "O", and when the absolute value of the maximum deflection amount of the doctor blade 36 is greater than 20 μm, the maximum deflection amount is indicated as "X".

[0130] [Table 1]

[0131] As can be seen from Table 1, in order to suppress the amount of variation in the SB gap G due to heat to within ±20 μm, the linear expansion coefficient difference α2-α1 needs to satisfy the following relational expression (Equation 1). (Formula 1) -0.45×10 -5 [m / ℃]≦α2-α1≦0.55×10 -5 [m / ℃]

[0132] Therefore, the difference in linear expansion coefficient α2-α1 is -0.45×10 -5 [m / ℃] or more 0.55×10 -5 The resin constituting the developing frame 30 and the resin constituting the doctor blade 36 may be selected so that the linear expansion coefficient difference α2-α1 satisfies (Formula 1) as the resin constituting the developing frame 30 and the resin constituting the doctor blade 36 is equal to or less than ±20 μm. It is more preferable to make the linear expansion coefficient difference α2-α1 zero. In order to make the linear expansion coefficient difference α2-α1 zero, the same resin may be selected as the resin constituting the developing frame 30 and the resin constituting the doctor blade 36.

[0133] In addition, since the cover frame 40 is fixed to the developing frame 30, if the deformation amounts of the developing frame 30 and the cover frame 40 due to temperature change differ, the deformation in the warping direction of the cover frame 40 leads to a change in the size of the SB gap G. As a result, even if the SB gap G is adjusted with high accuracy in the positioning process of the doctor blade 36, there is a risk that the size of the SB gap G will change due to temperature changes during the image forming operation (developing operation).

[0134] To suppress the fluctuation in the size of the SB gap G caused by temperature changes, the linear expansion coefficient α2 of the resin constituting the sleeve support portion 42 and the blade attachment portion 41 of the developing frame 30 (single unit) and the linear expansion coefficient α3 of the resin constituting the cover frame 40 (single unit) are related. As described above, it is necessary to suppress the amount of fluctuation in the SB gap G caused by heat to ±20 μm or less. The linear expansion coefficient of the resin constituting the developing frame 30 having the sleeve support portion 42 and the blade attachment portion 41 is α2 [m / °C], and the linear expansion coefficient of the resin constituting the cover frame 40 is α3 [m / °C].

[0135] Hereinafter, the difference between the linear expansion coefficient α2 of the resin constituting the developing frame 30 having the sleeve support portion 42 and the blade attachment portion 41 and the linear expansion coefficient α3 of the resin constituting the cover frame 40 will be referred to as the linear expansion coefficient difference α3-α2. As with Table 1, this linear expansion coefficient difference α3-α2 needs to satisfy the following relational expression (Equation 2). (Formula 2) -0.45×10 -5 [m / ℃]≦α3-α2≦0.55×10 -5 [m / ℃]

[0136] Therefore, the difference in linear expansion coefficient α3-α2 is -0.45×10 -5 [m / ℃] or more 0.55×10 -5The resin constituting the developing frame 30 and the resin constituting the cover frame 40 may be selected so that the linear expansion coefficient difference α3-α2 satisfies (Equation 2) as the resin constituting the developing frame 30 and the resin constituting the cover frame 40 is equal to or less than ±20 μm. It is more preferable to make the linear expansion coefficient difference α3-α2 zero. In order to make the linear expansion coefficient difference α3-α2 zero, the same resin may be selected as the resin constituting the developing frame 30 and the resin constituting the cover frame 40.

[0137] When adhesive A is applied to the doctor blade 36 and the developing frame 30, the linear expansion coefficients of the doctor blade 36 and the developing frame 30 to which adhesive A is applied vary. However, the volume of adhesive A applied to the doctor blade 36 and the developing frame 30 is very small, and the effect on the dimensional fluctuation in the thickness direction of adhesive A due to temperature change is negligible. Therefore, when adhesive A is applied to the doctor blade 36 and the developing frame 30, the deformation in the warp direction of the doctor blade 36 caused by the fluctuation in the linear expansion coefficient difference α2-α1 is negligible.

[0138] Generally, resin molded products tend to have poorer abrasion resistance than metal molded products. One factor affecting the abrasion resistance of the doctor blade 36 is the agent pressure applied to the doctor blade 36. In selecting a resin for the doctor blade 36, it is generally known that the greater the surface hardness of the resin, the better the abrasion resistance.

[0139] Therefore, in consideration of wear resistance, a resin having a surface hardness of 100 or more on the L scale of Rockwell hardness (JIS K7202-2) is selected as the resin constituting the doctor blade 36. This makes it possible to suppress wear of the doctor blade 36 during the image forming operation (developing operation). The doctor blade 36 made of such a resin only wears to 10 μm or less even in a durability test equivalent to about 500,000 sheets. The greater the surface hardness of the doctor blade 36, the more improved the wear resistance of the doctor blade 36 becomes, but the mass productivity of the doctor blade 36 tends to decrease. This is because resins with high surface hardness generally contain a large amount of reinforcing agent such as glass fiber. When molding a resin with such high surface hardness in a mold, the reinforcing agent added to the resin damages the mold. Therefore, if a certain amount or more of reinforcing agent is added to the resin, the mass productivity of the doctor blade 36 cannot be maintained. Therefore, it has been found that mass productivity of the doctor blade 36 can be ensured by selecting a resin having a surface hardness of 100 or less on the M scale of Rockwell hardness (JIS K7202-2) as the resin constituting the doctor blade 36.

[0140] In the first embodiment, in consideration of both the wear resistance and mass productivity of the doctor blade 36, the doctor blade 36 is molded from a resin having a surface hardness of 100 or more on the Rockwell hardness L scale and 100 or less on the Rockwell hardness M scale. Examples of resins having a surface hardness of 100 or more on the Rockwell hardness L scale and 100 or less on the Rockwell hardness M scale include the following. For example, a resin (hereinafter referred to as resin X) having polyphenylene ether (PPE) and polystyrene (PS) as base materials and containing 30% to 35% by weight of a reinforcing agent is included. Another example is a resin (hereinafter referred to as resin Y) having polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) as base materials and containing 20% ​​to 30% by weight of a reinforcing agent.

[0141] Therefore, in consideration of both the wear resistance and mass productivity of the doctor blade 36, assume that "resin X" or "resin Y" is selected as the resin constituting the doctor blade 36. In this case, the resin constituting the developing frame 30 should be selected so that the difference between the linear expansion coefficient α1 of the doctor blade 36 and the linear expansion coefficient α2 of the developing frame 30 (linear expansion coefficient difference α2-α1) satisfies the above-mentioned (Formula 1).

[0142] When "resin X" is selected as the resin constituting the doctor blade 36, the linear expansion coefficient difference α2-α1 satisfies the above-mentioned (formula 1) by selecting "resin X" or "resin Y" as the resin constituting the developing frame 30. Also, when "resin Y" is selected as the resin constituting the doctor blade 36, the linear expansion coefficient difference α2-α1 satisfies the above-mentioned (formula 1) by selecting "resin X" or "resin Y" as the resin constituting the developing frame 30.

[0143] On the other hand, when "resin X" is selected as the resin constituting the developing frame 30, "resin X" or "resin Y" may be selected as the resin constituting the cover frame 40. In this case, the difference between the linear expansion coefficient α2 of the developing frame 30 and the linear expansion coefficient α3 of the cover frame 40 (linear expansion coefficient difference α2-α3) satisfies the above-mentioned (Equation 2). Also, when "resin Y" is selected as the resin constituting the developing frame 30, the linear expansion coefficient difference α2-α3 satisfies the above-mentioned (Equation 2) by selecting "resin X" or "resin Y" as the resin constituting the cover frame 40.

[0144] As described above, in the first embodiment, the doctor blade 36 is used in which the straightness of the coat amount control surface 36r is the same as that of a typical resin molded product. Then, a part of the area of ​​the doctor blade 36 corresponding to the maximum image area is bent to correct the straightness of the coat amount control surface 36r, and the doctor blade 36 is fixed to the blade attachment surface 41s over substantially the entire area corresponding to the maximum image area. With this configuration, even if a resin doctor blade for A3 size, which has a low straightness accuracy of the coat amount control surface 36r, is used, the SB gap G can be set within a range of approximately 300 μm±30 ​​μm (i.e., the adjustment range of the SB gap G) over the longitudinal direction of the developing sleeve.

[0145] In the first embodiment, the resin constituting the doctor blade 36 was selected in consideration of both the wear resistance and mass productivity of the doctor blade 36. The resin constituting the developing frame 30 was selected so that the difference between the linear expansion coefficient α1 of the doctor blade 36 and the linear expansion coefficient α2 of the developing frame 30 (linear expansion coefficient difference α2-α1) satisfies the above-mentioned (Formula 1). Furthermore, the resin constituting the cover frame 40 was selected so that the difference between the linear expansion coefficient α2 of the developing frame 30 and the linear expansion coefficient α3 of the cover frame 40 (linear expansion coefficient difference α2-α3) satisfies the above-mentioned (Formula 2). As a result, it is possible to suppress the fluctuation in the size of the SB gap G caused by temperature changes during the image forming operation (developing operation).

[0146] In the first embodiment, the doctor blade 36 is fixed over substantially the entire area corresponding to the maximum image area to the blade attachment portion 41 of the developing frame 30. This increases the rigidity of the doctor blade 36 when fixed to the developing frame 30, compared to when only both ends (two locations) of the doctor blade 36 in the longitudinal direction of the doctor blade 36 are fixed to the blade attachment portion 41. As a result, it is possible to suppress fluctuations in the size of the SB gap G caused by the developer pressure applied to the doctor blade 36 during the image forming operation (developing operation).

[0147] [Second embodiment] In the above-described first embodiment, an example has been described in which the adhesive A is applied over substantially the entire area of ​​the area corresponding to the maximum image area on the blade attachment surface 41s of the developing frame 30. By applying the adhesive A over substantially the entire area of ​​the area corresponding to the maximum image area on the blade attachment surface 41s of the developing frame 30, the deflected area of ​​the doctor blade 36 corresponding to the maximum image area is fixed to the blade attachment surface 41s. This prevents the area of ​​the doctor blade 36 corresponding to the maximum image area, which is deflected to correct the straightness of the coat amount control surface 36r, from returning from the deflected state to its original state before the deflection.

[0148] On the other hand, the second embodiment differs from the first embodiment in that the device 100 does not apply the adhesive A to the blade mounting surface 41s of the developing frame 30 over substantially the entire area of ​​the area corresponding to the maximum image area. In the second embodiment, the device 100 stores in a memory the area of ​​the doctor blade 36 that is bent to correct the straightness of the coat amount control surface 36r among the areas corresponding to the maximum image area. Next, the device 100 determines a predetermined area to which the adhesive A is applied among the areas corresponding to the maximum image area of ​​the blade mounting surface 41s of the developing frame 30 based on the information on the bent area of ​​the doctor blade 36 stored in the memory. Then, the device 100 applies the adhesive A to the determined predetermined area of ​​the blade mounting surface 41s. The application width and film thickness of the adhesive A to be applied to the blade mounting surface 41s may be determined from the adhesive strength and application amount of the adhesive A in consideration of the man-hours and costs. As a result, the bent area among the areas corresponding to the maximum image area of ​​the doctor blade 36 is fixed to the blade mounting surface 41s.

[0149] In order to suppress the variation in the size of the SB gap G caused by the agent pressure applied to the doctor blade 36 during the image forming operation (developing operation), it is necessary to increase the rigidity of the doctor blade 36 in a state where it is fixed to the developing frame 30. Therefore, it is preferable that the device 100 further applies the adhesive A to at least three locations including both ends and an approximate center of the area corresponding to the maximum image area of ​​the blade mounting surface 41s of the developing frame 30, in addition to the predetermined area of ​​the determined blade mounting surface 41s. Note that the approximate center of the area corresponding to the maximum image area of ​​the blade mounting surface 41s covers an area shifted in parallel to one end side or the other end side by a length of 10% or less of the longitudinal length of the area, based on the center of the area corresponding to the maximum image area of ​​the blade mounting surface 41s.

[0150] As a result, in addition to the deflected area of ​​the doctor blade 36 corresponding to the maximum image area, at least three locations including both ends and a substantial center of the area corresponding to the maximum image area of ​​the doctor blade 36 are fixed to the blade attachment surface 41s. This further increases the rigidity of the doctor blade 36 in the state where it is fixed to the developing frame 30, thereby suppressing fluctuations in the size of the SB gap G caused by the agent pressure applied to the doctor blade 36 during the image forming operation (developing operation).

[0151] The method of fixing at least three points including both ends and the approximate center of the area corresponding to the maximum image area of ​​the doctor blade 36 to the blade mounting surface 41s is not limited to fixing with adhesive A, and may be fixing with screws. FIG. 17 is a perspective view showing the configuration of the developing device 300 in which three points, both ends and the approximate center of the area corresponding to the maximum image area of ​​the doctor blade 36, are fixed to the blade mounting surface 41s with screws 80. FIG. 18 is a cross-sectional view of the developing device 300 at the cross section H of FIG. 17, showing the configuration in the vicinity of the doctor blade 36 fixed to the blade mounting portion 41 of the developing frame 30 with screws 80. In FIG. 17, the same reference numerals as in FIG. 2 indicate the same configuration. Also, in FIG. 18, the same reference numerals as in FIG. 15 indicate the same configuration.

[0152] 17, an insert nut is inserted into a fixed position on the blade mounting surface 41s of the developing frame 30. Then, a screw 80 is fastened to the insert nut to improve the fastening force for fixing the doctor blade 36 to the blade mounting surface 41s. If the fastening force can be maintained, the insert nut may be eliminated and a self-tapping screw, in which the screw 80 itself cuts a tap when it is screwed in, may be used instead.

[0153] When the doctor blade 36 is fixed to the blade attachment surface 41s with the screw 80, the doctor blade 36 may be fixed to the blade attachment surface 41s with the screw 80 after the adjustment of the SB gap G is completed in the positioning step described above. The gripping portion 37 of the doctor blade 36 is shifted from the screw fastening portion provided on the doctor blade 36 for fastening to the blade attachment surface 41s with the screw 80 by an amount equivalent to the fixing width per location by the screw 80. In the example of Fig. 17, the fixing width per location by the screw 80 corresponds to the width at which the screw 80 is fastened, and is about 5 mm.

[0154] (Other embodiments) The present invention is not limited to the above-described embodiments, and various modifications (including organic combinations of the respective embodiments) are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0155] In the above embodiment, as shown in Fig. 4, the developer guide portion 35 and the developing frame 30 are integrally formed, and the developer guide portion 35 and the doctor blade 36 are formed separately, but the present invention is not limited to this. As long as the doctor blade 36 (single unit) has a rigidity such that the finger 101 can bend the doctor blade 36, and the developer flow and developer pressure during the developing operation are within the range of the design values, the developer guide portion 35 and the doctor blade 36 may be integrally formed.

[0156] In the above embodiment, the image forming apparatus 60 is configured to use the intermediate transfer belt 61 as an image carrier as shown in Fig. 1, but the present invention is not limited to this. It is also possible to apply the present invention to an image forming apparatus configured to transfer recording materials by directly contacting the recording materials with the photosensitive drums 1 in sequence. In this case, the photosensitive drums 1 constitute a rotatable image carrier that carries a toner image.

[0157] In the above embodiment, the developing device 3 is described as an example in which the developing sleeve 70 rotates counterclockwise and the doctor blade 36 is disposed below the developing sleeve 70 as shown in Fig. 2, but the present invention is not limited to this. It is also possible to apply the present invention to a developing device 3 in which the developing sleeve 70 rotates clockwise and the doctor blade 36 is disposed above the developing sleeve 70.

[0158] In the above embodiment, the developing device 3 is configured such that the developing chamber 31 and the stirring chamber 32 are arranged side by side in the horizontal direction as shown in Fig. 2, but the present invention is not limited to this. It is also possible to apply the present invention to a developing device 3 configured such that the developing chamber 31 and the stirring chamber 32 are arranged side by side vertically in the direction of gravity.

[0159] In addition, in the above embodiment, the developing device 3 has been described as a single unit, but the same effect can be obtained even if the image forming section 600 (see FIG. 1) including the developing device 3 is integrated into a unit and is in the form of a process cartridge that is detachably attached to the image forming device 60. Furthermore, the present invention can be applied to image forming devices 60 that include the developing device 3 or process cartridge, regardless of whether they are monochrome or color machines. [Explanation of symbols]

[0160] 3. Developing device 30 Developing frame 36 Doctor Blade 41 Blade attachment part 70 Developing sleeve

Claims

1. A manufacturing method of a developing device including a developer carrier which carries and transports a developer to a development position, a resin-made regulating blade which is disposed opposite to the developer carrier in a non-contact manner and regulates an amount of developer carried on the developer carrier, and a resin-made developing frame which has an attachment portion to which the regulating blade is attached and which supports the developer carrier, comprising: a coating step of coating the mounting portion with an adhesive; a positioning step of adjusting a force for bending the regulating blade so that a size of a gap between the developer carrier supported on the developing frame and the regulating blade attached to the attachment portion falls within a predetermined tolerance range along the longitudinal direction of the developer carrier after the adhesive applied to the attachment portion in the application step is brought into contact with the regulating blade and before hardening of the adhesive applied to the attachment portion in the application step is completed, and determining a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of a plurality of points in the longitudinal direction of the regulating blade; A manufacturing method of a developing device comprising the steps of:

2. The positioning step includes adjusting the force in a state where the regulating blade is landed on the attachment portion to which the adhesive is applied in the application step, and determining a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of the plurality of points in the longitudinal direction of the regulating blade. The method for manufacturing a developing device according to claim 1 .

3. The method further includes a measuring step of measuring the size of the gap, The positioning step adjusts the force so that the size of the gap measured in the measuring step falls within the range of the predetermined tolerance along the longitudinal direction of the developer carrier, and determines a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of the plurality of points in the longitudinal direction of the regulating blade.

3. The method for manufacturing a developing device according to claim 1, wherein the developing device is a semiconductor device.

4. The positioning step adjusts the force so that the size of the gap at each of a plurality of positions in the longitudinal direction of the developer carrier is 270 μm or more and 330 μm or less, and determines a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of the plurality of positions in the longitudinal direction of the regulating blade.

4. The method for manufacturing a developing device according to claim 1,

5. In the measuring step, a light source installed inside the developing frame irradiates light from inside the developing frame toward the gap, and an imaging unit installed outside the developing frame images the light emitted from the gap to the outside of the developing frame, thereby measuring the size of the gap.

4. The method for manufacturing a developing device according to claim 3.

6. The developer carrier is rotatable, The measuring step measures the size of the gap while the developer carrier is rotating.

6. The method for manufacturing a developing device according to claim 3 or 5.

7. After the adhesive applied to the attachment portion in the application step has been cured, an absolute value of a difference between values ​​of the gap at a plurality of positions in the longitudinal direction of the developer carrier and a median value of the gap at the plurality of positions is 10% or less of the median value.

7. The method for manufacturing a developing device according to claim 1,

8. The plurality of locations in the longitudinal direction of the regulating blade include one end of the region of the regulating blade corresponding to the maximum image region, the other end of the region of the regulating blade corresponding to the maximum image region, and a central portion of the region of the regulating blade corresponding to the maximum image region. The method for manufacturing a developing device according to any one of claims 1 to 7.

9. The length of the region of the regulating blade corresponding to the maximum image region is a length corresponding to A3 size. The method for manufacturing a developing device according to claim 8 .

10. A manufacturing method of a developing device including a developer carrier which carries and transports a developer to a development position, a resin-made regulating blade which is disposed opposite to the developer carrier in a non-contact manner and regulates an amount of developer carried on the developer carrier, and a resin-made developing frame which has an attachment portion to which the regulating blade is attached and which supports the developer carrier, comprising: a coating step of coating the regulating blade with an adhesive; a positioning step of adjusting a force for bending the regulating blade so that a size of a gap between the developer carrier supported on the developing frame and the regulating blade attached to the attachment portion falls within a predetermined tolerance range along the longitudinal direction of the developer carrier, after the adhesive applied to the regulating blade in the application step is brought into contact with the attachment portion and before hardening of the adhesive applied to the regulating blade in the application step is completed, and determining a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of a plurality of points in the longitudinal direction of the regulating blade; A manufacturing method of a developing device comprising the steps of:

11. The positioning step includes adjusting the force in a state where the regulating blade to which the adhesive has been applied in the application step is landed on the attachment portion, and determining a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of the plurality of points in the longitudinal direction of the regulating blade. The method for manufacturing a developing device according to claim 10 .

12. The method further includes a measuring step of measuring the size of the gap, The positioning step adjusts the force so that the size of the gap measured in the measuring step falls within the range of the predetermined tolerance along the longitudinal direction of the developer carrier, and determines a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of the plurality of points in the longitudinal direction of the regulating blade.

12. The method for manufacturing a developing device according to claim 10 or 11.

13. The positioning step adjusts the force so that the size of the gap at each of a plurality of positions in the longitudinal direction of the developer carrier is 270 μm or more and 330 μm or less, and determines a position for attaching the regulating blade to the attachment portion while applying the adjusted force to each of the plurality of positions in the longitudinal direction of the regulating blade.

13. The method for manufacturing a developing device according to claim 10,

14. In the measuring step, a light source installed inside the developing frame irradiates light from inside the developing frame toward the gap, and an imaging unit installed outside the developing frame images the light emitted from the gap to the outside of the developing frame, thereby measuring the size of the gap. The method for manufacturing a developing device according to claim 12 .

15. The developer carrier is rotatable, The measuring step measures the size of the gap while the developer carrier is rotating.

15. The method for manufacturing a developing device according to claim 12 or 14.

16. After the adhesive applied to the attachment portion in the application step has been cured, an absolute value of a difference between values ​​of the gap at a plurality of positions in the longitudinal direction of the developer carrier and a median value of the gap at the plurality of positions is 10% or less of the median value.

16. The method for manufacturing a developing device according to claim 10,

17. The plurality of locations in the longitudinal direction of the regulating blade include one end of the region of the regulating blade corresponding to the maximum image region, the other end of the region of the regulating blade corresponding to the maximum image region, and a central portion of the region of the regulating blade corresponding to the maximum image region. The method for manufacturing a developing device according to any one of claims 10 to 16.

18. The length of the region of the regulating blade corresponding to the maximum image region is a length corresponding to A3 size. The method for manufacturing a developing device according to claim 17 .

Images