JP7118715B2 - Developing device manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a developing device having a regulation blade made of resin .

The developing device has a coat amount that regulates the amount of developer (developer coat amount) carried on the surface of a developer carrier that carries developer to develop an electrostatic latent image formed on the image carrier. A regulating blade (developer regulating member) having a regulating surface (regulating portion) is provided. The regulating blade is arranged across the longitudinal direction of the developer carrier so as to face the developer carrier with a predetermined gap (hereinafter referred to as SB gap G) between itself and 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 of the developing container (developing frame) and the coat amount regulating surface of the regulating blade attached to the frame of the developing container. It's about. By adjusting the size of the SB gap G, the amount of developer conveyed to the developing area where the developer carrier faces the image carrier is adjusted.

The developing device described in Patent Document 1 includes a resin developer regulating member molded from resin and a resin developing container frame body molded from resin.

JP 2014-197175 A

As the width of the sheet on which an image is to be formed increases, the area of the coating amount regulating surface corresponding to the image area that can be formed on the image carrier increases, so the length of the regulating blade in the longitudinal direction increases. . When a regulating blade having a large length in the longitudinal direction is molded from resin, it is difficult to ensure the straightness of the coating amount regulating surface of the resin regulating blade molded from resin. This is because when the regulation blade having a large length in the longitudinal direction is molded from resin, the rate at which the thermally expanded resin thermally shrinks tends to vary. Therefore, with the resin regulating blade, the SB gap G tends to vary in the longitudinal direction of the developer carrier due to the straightness of the coat amount regulating surface of the regulating blade as the length of the regulating blade in the longitudinal direction increases. tend to become If the SB gap G is different in the longitudinal direction of the developer carrier, the amount of developer carried on the surface of the developer carrier may be uneven in the longitudinal direction of the developer carrier.

Therefore, in a developing device provided with a resin-made regulation blade, the SB gap G is maintained in a state in which the regulation blade is fixed to the mounting portion of the developing frame regardless of the straightness of the coating amount regulation surface of the regulation blade. It is desired that the longitudinal direction of the developer carrying member is within a predetermined range.

The present invention has been made in view of the above problems. It is an object of the present invention to provide a gap between a developer carrier supported by a developing frame and a resin regulating blade attached to a mounting portion of the developing frame so that the length of the developer carrier extends in the longitudinal direction of the developer carrier. To provide a manufacturing method of a developing device that is within a predetermined range along the line .

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 developer bearing member that carries and conveys the developer to a development position, and a resin that is arranged to face the developer bearing member without contact and regulates the amount of developer carried on the developer bearing member. and a developing frame body made of resin, which has a mounting portion to which the regulating blade is mounted and supports the developer carrying member, the developing device manufacturing method comprising: The regulating blade is arranged such that the size of the gap between the supported developer carrier and the regulating blade attached to the mounting portion is within a predetermined range along the longitudinal direction of the developer carrier. a positioning step of determining a position where the regulating blade is attached to the mounting portion while applying a force for bending the regulating blade to each of a plurality of locations in the longitudinal direction of the regulating blade; and after the positioning step is completed, the An adhesive is used while maintaining the state in which the regulation blade is bent by the force applied to the regulation blade so that the adhesion operation between the regulation blade and the mounting portion is started. and an attaching step of attaching the regulating blade to the attaching portion.

According to the present invention, the size of the gap between the developer carrier supported by the developing frame and the resin regulating blade attached to the mounting portion of the developing frame is adjusted in the longitudinal direction of the developer carrier. It can be made to be within a predetermined range along .

1 is a cross-sectional view showing the configuration of an image forming apparatus; FIG. 1 is a perspective view showing the configuration of a developing device according to a first embodiment; FIG. 1 is a perspective view showing the configuration of a developing device according to a first embodiment; FIG. 2 is a cross-sectional view showing the configuration of the developing device according to the first embodiment; FIG. FIG. 3 is a perspective view showing the configuration of a resin-made development frame (single body); FIG. 3 is a perspective view showing the configuration of a resin doctor blade (single body); FIG. 4 is a schematic diagram for explaining the rigidity of a resin doctor blade (single body); FIG. 3 is a schematic diagram for explaining the rigidity of a resin-made development frame (single body); FIG. 4 is a schematic diagram for explaining steps of a method for fixing a resin doctor blade. FIG. 4 is a schematic diagram for explaining steps of a method for fixing a resin doctor blade. FIG. 4 is a schematic diagram for explaining steps of a method for fixing a resin doctor blade. FIG. 4 is a schematic diagram for explaining steps of a method for fixing a resin doctor blade. FIG. 4 is a schematic diagram for explaining steps of a method for fixing a resin doctor blade. FIG. 4 is a schematic diagram for explaining steps of a method for fixing a resin doctor blade. FIG. 4 is a cross-sectional view for explaining deformation of a resin doctor blade caused by agent pressure; FIG. 4 is a perspective view for explaining deformation of a resin doctor blade caused by temperature change; FIG. 5 is a perspective view showing the configuration of a developing device according to a second embodiment; FIG. 5 is a cross-sectional view showing the configuration of a developing device according to a second embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the following embodiments do not limit the present invention according to the claims, and all combinations of features described in the first embodiment are not essential to the solution of the present invention. Not exclusively. The present invention can be implemented in various applications such as printers, various printing machines, copiers, facsimiles, and multi-function machines.

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

The image forming section 600 includes a rotatable photosensitive drum 1 as an image carrier. Further, the image forming unit 600 includes a charging roller 2 as charging means, a developing device 3 as developing means, a primary transfer roller 4 as primary transfer means, and a primary transfer roller 4 as primary transfer means. , a photoreceptor cleaner 5 as a photoreceptor cleaning means.

Each of the developing devices 3 is detachable from the image forming device 60 . Each developing device 3 has a developing container 50 containing a two-component developer (hereinafter simply referred to as developer) containing non-magnetic toner (hereinafter simply referred to as toner) and magnetic carrier. In addition, toner cartridges containing toner of each color of Y, M, C, and Bk are detachable from the image forming apparatus 60 . The respective color toners of Y, M, C, and Bk are supplied to the developing containers 50 through the toner conveying paths. Details of the developing device 3 will be described later with reference to FIGS. 2 to 4, and details of the developer container 50 will be described later with reference to FIG.

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 conveyed in the direction of arrow C in FIG. The inner secondary transfer roller 66 also serves as a drive roller for driving the intermediate transfer belt 61 . As the inner secondary transfer roller 66 rotates, the intermediate transfer belt 61 rotates in the direction of arrow C in FIG.

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

An intermediate transfer body cleaner 8 as belt cleaning means is in contact with the tension roller 6 via the intermediate transfer belt 61 . Further, a secondary transfer outer roller 67 as a secondary transfer means is arranged at a position facing the secondary transfer inner roller 66 with the intermediate transfer belt 61 interposed therebetween. The intermediate transfer belt 61 is sandwiched between a secondary transfer inner roller 66 and a 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 . At the secondary transfer nip portion, the toner image is attracted to the surface of the sheet S (paper, film, etc.) by applying a predetermined pressure and transfer bias (electrostatic load bias).

Sheets S are stacked and stored in a sheet storage unit 62 (for example, a feeding cassette, a feeding deck, or the like). The feeding unit 63 feeds the sheet S in time with the image forming timing by using, for example, a friction separation method using a feeding roller or the like. The sheet S sent out by the feeding means 63 is conveyed to the registration rollers 65 arranged in the middle of the conveying path 64 . After skew correction and timing correction are performed by the registration rollers 65, the sheet S is conveyed to the secondary transfer nip portion. At the secondary transfer nip portion, the sheet S and the toner image are synchronized in timing, and secondary transfer is performed.

A fixing device 9 is disposed downstream of the secondary transfer nip portion in the sheet S conveying direction. The fixing device 9 applies a predetermined amount of 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. FIG. The sheet S on which the image has been fixed in this way is discharged to the discharge tray 601 as it is by forward rotation of the discharge roller 69 .

In the case of double-sided image formation, the ejection roller 69 rotates forward to convey the sheet S until the trailing edge of the sheet S passes through the switching flapper 602, and then rotates the ejection roller 69 in the reverse direction. As a result, the sheet S is conveyed to the double-sided conveying path 603 with the leading and trailing edges exchanged. After that, the sheet is conveyed again to the conveying path 64 by the re-feeding roller 604 in time with the next image forming timing.

(Image forming process)
During image formation, the photosensitive drum 1 is rotationally driven by a motor. The charging roller 2 uniformly charges the surface of the photosensitive drum 1 which is driven to rotate. The exposure device 68 forms an electrostatic latent image on the surface of the photosensitive drum 1 charged by the charging roller 2 based on the image information signal input to the image forming device 60 . The photoreceptor drum 1 can form electrostatic latent images of a plurality of sizes.

The developing device 3 has a rotatable developing sleeve 70 as a developer carrier that carries developer. The developing device 3 develops the electrostatic latent image formed on the surface of the photoreceptor drum 1 using the developer carried on the surface of the developing sleeve 70 . As a result, the toner adheres to the exposed portion on the surface of the photoreceptor drum 1 to form a visible image. 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 photoreceptor drum 1 after the primary transfer is collected by the photoreceptor cleaner 5 and prepared for the next image forming process.

The image forming processes of the respective colors, which are processed in parallel by the image forming units 600 of the respective colors of Y, M, C, and Bk, are sequentially superimposed on the toner images of the upstream colors primarily transferred onto the intermediate transfer belt 61 . done. 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 (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 member cleaner 8 . The fixing device 9 fixes the toner image transferred onto the sheet S. As shown in FIG. The recording material S subjected to the fixing process by the fixing device 9 is discharged 601 to the discharge tray.

A series of image forming processes as described above is completed, and preparations are made for the next image forming operation.

(Structure of 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. FIG. 4 is a sectional view of the developing device 3 along section H in FIG.

The developing device 3 includes a resin-made developing frame body (hereinafter simply referred to as the developing frame body 30) molded from resin, and a resin-made cover formed separately from the developing frame body 30 and molded from resin. A developer container 50 configured by a frame (hereinafter simply referred to as a cover frame 40) is provided. 2 and 4 show the state in which the cover frame 40 is attached to the developing frame 30, and FIG. 3 shows the cover frame 40 attached to the developing frame 30. FIG. It shows the state without The details of the configuration of the development frame 30 (single body) will be described later with reference to FIG.

The developer container 50 is provided with 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 arranged with respect to the developing container 50 so that a part of the developing sleeve 70 is exposed to the opening of the developing container 50 . Bearings 71 that are bearing members are provided at both ends of the developing sleeve 70 .

The interior of the developing container 50 is partitioned into a developing chamber 31 as a first chamber and a stirring chamber 32 as a second chamber by a vertically extending partition wall 38 . The developing chamber 31 and the stirring chamber 32 are connected at both ends in the longitudinal direction via two communicating portions 39 of the partition wall 38 . Therefore, the developer can be communicated between the developing chamber 31 and the stirring chamber 32 through the communicating portion 39 . The developing chamber 31 and the stirring chamber 32 are arranged side by side in the horizontal direction.

Inside the developing sleeve 70 is fixed a magnet roll as magnetic field generating means that has a plurality of magnetic poles along the rotation direction of the developing sleeve 70 and generates a magnetic field for carrying the developer on the surface of the developing sleeve 70 . are arranged as follows. The developer in the developing chamber 31 is pumped up under the influence of the magnetic field generated by the magnetic poles of the magnet roll and 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.

A first conveying screw 33 serving as conveying means for agitating and conveying the developer in the developing chamber 31 is arranged in the developing chamber 31 so as to face the developing sleeve 70 . The first conveying screw 33 includes a rotating shaft 33a as a rotatable shaft portion and a spiral blade portion 33b as a developer conveying portion provided along the outer periphery of the rotating shaft 33a. rotatably supported. A bearing member is provided at each of both ends of the rotary shaft 33a.

Further, in the stirring chamber 32 , a second conveying screw 34 is arranged as a conveying means for agitating the developer in the stirring chamber 32 and conveying the same 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 helical blade portion 34b as a developer conveying portion provided along the outer circumference of the rotating shaft 34a. rotatably supported. A bearing member is provided at each of both ends of the rotating shaft 34a. By rotating the first conveying screw 33 and the second conveying screw 34 , the developer circulates between the developing chamber 31 and the stirring chamber 32 via the communicating portion 39 .

In the developer container 50, a regulating blade (hereinafter referred to as a doctor blade 36) as a developer regulating member for regulating the amount of developer carried on the surface of the developing sleeve 70 (also referred to as the developer coat amount) is provided for the developer. It is attached facing the surface of the sleeve 70 in a non-contact manner. The doctor blade 36 has a coat amount regulating surface 36 r as a regulating portion that regulates 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 body) will be described later with reference to FIG.

The doctor blade 36 is provided with a predetermined gap (hereinafter referred to as an SB gap G) with the developing sleeve 70 over the longitudinal direction of the developing sleeve 70 (that is, in a direction parallel to the rotation axis direction of the developing sleeve 70). It is arranged to face the developing sleeve 70 . In the present invention, the SB gap G is an area corresponding to the maximum image area formable on the surface of the photosensitive drum 1 of the developing sleeve 70 (so-called maximum image area of the developing sleeve 70), and the corresponding gap of the doctor blade 36. Suppose that it is the shortest distance between the area corresponding to the maximum image area (the so-called maximum image area of the doctor blade 36). In the first embodiment, the photosensitive drum 1 is capable of forming electrostatic latent images of a plurality of sizes. An image area corresponding to a large size (for example, A3 size) shall be indicated. On the other hand, in the modification in which the photosensitive drum 1 can form an electrostatic latent image of only one size, the maximum image area is the size of the image area of that one size that can be formed on the photosensitive drum 1. shall be read as indicating that

The doctor blade 36 is arranged substantially facing the peak position of the magnetic flux density of the magnetic poles of the magnet roll. The developer supplied to the developing sleeve 70 is affected by the magnetic field generated by the magnetic poles of the magnet roll. Further, the developer that is regulated and scraped by the doctor blade 36 tends to stay 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 rotational direction of the developing sleeve 70 . Part of the developer in the developer pool is conveyed so as 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 coating amount regulating surface 36r of the doctor blade 36. FIG. In this manner, a thin layer of developer is formed on the surface of the developing sleeve 70 .

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

The developer conveyed to the development area rises in the development area to form magnetic ears. The toner in the developer is supplied to the photoreceptor drum 1 by the contact of the magnetic brush with the photoreceptor 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 developing sleeve 70 after passing through the developing region and supplying the toner to the photosensitive drum 1 (hereinafter referred to as the developer after the developing process) is formed between the same magnetic poles of the magnet roll. It is peeled off from the surface of the developing sleeve 70 by the repelling magnetic field. The developer stripped off from the surface of the developing sleeve 70 after the developing process drops into the developing chamber 31 and is collected into the developing chamber 31 .

As shown in FIG. 4, the developer container 50 is provided with a developer guide portion 35 for guiding the developer to be transported toward the SB gap G. As shown in FIG. The developer guide portion 35 and the developing frame 30 are formed integrally, and the developer guide portion 35 and the doctor blade 36 are formed separately. The developer guide portion 35 is formed inside the developing frame 30 and arranged upstream of the coat amount regulating surface 36 r of the doctor blade 36 in the rotation direction of the developing sleeve 70 . By stabilizing the flow of the developer by the developer guide portion 35 and arranging the developer so as to have a predetermined developer density, the coating amount regulation surface 36r of the doctor blade 36 is in the closest proximity to the surface of the developing sleeve 70. A developer weight can be specified.

Further, as shown in FIG. 4 , the cover frame 40 is formed separately from the developing frame 30 and attached to the developing frame 30 . Further, the cover frame 40 partially covers the opening of the developing sleeve 30 so that the outer peripheral surface of the developing sleeve 70 is partially covered over the entire longitudinal direction of the developing sleeve 70 . At this time, the cover frame 40 partially covers 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. , welding, or the like.

Next, the configuration of the development frame 30 (single body) will be described with reference to the perspective view of FIG. FIG. 5 shows a state in which the cover frame 40 is not attached to the developing frame 30 .

The developing frame 30 has a developing chamber 31 and a stirring 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 .

The development frame 30 has a sleeve support portion 42 for rotatably supporting the development sleeve 70 by supporting bearings 71 provided at both ends of the development sleeve 70 . The development frame 30 also has a blade mounting portion 41 integrally formed with the sleeve support portion 42 and for mounting the doctor blade 36 thereon. FIG. 5 shows a virtual state in which the doctor blade 36 is lifted from the blade mounting portion 41. FIG.

In the first embodiment, in a state where the doctor blade 36 is attached to the blade attachment portion 41, the adhesive A applied to the blade attachment surface 41s of the blade attachment portion 41 is cured, thereby causing the blade attachment portion 41 to The doctor blade 36 is fixed at the end. Details of a method for fixing the doctor blade 36 to the blade attachment portion 41 will be described later with reference to FIG. 9 and subsequent figures.

(resin doctor blade)
In response to the increase in the width of the sheet S, such as the width of the sheet S on which the image is to be formed is A3 size, the coating amount regulation surface corresponding to the maximum image area that can be formed on the surface of the photosensitive drum 1 is changed. Due to the increased area, the longitudinal length of the doctor blade is increased.

When a doctor blade having a large length in the longitudinal direction is molded from resin, it is difficult to ensure the straightness of the coated amount regulating surface of the resin doctor blade molded from resin. This is because when a doctor blade having a large length in the longitudinal direction is molded from resin, the rate at which the thermally expanded resin thermally shrinks tends to vary. The straightness of the coating amount control surface is the difference between the maximum value and the minimum value of the outer shape of the coating amount control surface when a predetermined location of the coating amount control surface in the longitudinal direction of the coating amount control surface is used as a reference. Expressed as an absolute value. For example, the central portion of the coating amount regulating surface in the longitudinal direction of the coating amount regulating surface is the origin of the orthogonal coordinate system, a predetermined straight line passing through the origin is the X axis, and a straight line drawn from the origin perpendicular to the X axis is the X axis. Y-axis. In this orthogonal coordinate system, the straightness of the coat amount control surface is represented by the absolute value of the difference between the maximum value and the minimum value of the Y coordinate of the outer shape of the coat amount control surface.

For example, a resin doctor blade whose length in the longitudinal direction corresponds to A3 size (hereinafter referred to as a resin doctor blade corresponding to A3 size) was manufactured with the accuracy of a general resin molded product. In this case, the straightness of the coating amount regulating surface is about 300 μm to 500 μm. Further, even if a resin doctor blade corresponding to A3 size is manufactured with high precision using a high-precision resin material, the straightness of the coating amount control surface is about 100 μm to 200 μm.

Therefore, with the resin doctor blade, the longer the length of the doctor blade in the longitudinal direction, the more the SB gap tends to vary in the longitudinal direction of the developer carrier due to the straightness of the coating amount regulating surface. . If the SB gap is different in the longitudinal direction of the developer carrier, there is a possibility that the amount of developer carried on the surface of the developer carrier may be uneven in the longitudinal direction of the developer carrier.

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 within a predetermined range in the longitudinal direction of the developing sleeve 70. It is something that makes you feel inside. Specifically, in the first embodiment, the tolerance of the SB gap G (that is, the tolerance for the target value of the SB gap G) is set to ±10% or less, and the SB gap G extends in the longitudinal direction of the developing sleeve 70 within a predetermined range. be inside.

In the first embodiment, it is determined whether the SB gap G is within a predetermined range along the longitudinal direction of the developing sleeve 70 by the method described below. Details of the method for measuring (calculating) the SB gap G will be described later with reference to FIG.

First, the area corresponding to the maximum image area of the doctor blade 36 is divided into four or more at equal intervals, and each divided portion of the doctor blade 36 (however, the both ends and the central portion of the area corresponding to the maximum image area of the doctor blade 36 are ), the SB gap G is measured at five or more locations. 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 samples of the measured values of the SB gap G measured at five or more locations. At this time, 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 minimum value of the SB gap G and the median value of the SB gap G The absolute value of the difference should be 10% or less of the median value of the SB gap G. In this case, it is assumed that the tolerance of the SB gap G is ±10% or less, and that the SB gap G is within a predetermined range along the longitudinal direction of the developing sleeve 70 .

For example, when the median value of the SB gap G is 300 μm from samples of measured values of the SB gap G measured at five or more locations, the maximum value of the SB gap G is 330 μm or less and the minimum value of the SB gap G is 270 μm. Anything above that is fine. That is, in this case, the adjustment value of the SB gap G is 300 .mu.m.+-.30 .mu.m, which means that the tolerance of the SB gap G is allowed up to 60 .mu.m. For this reason, even if a resin doctor blade corresponding to A3 size is manufactured with the accuracy of a general resin molded product, even if it is manufactured with high precision using a high-precision resin material, the straightness of the coating amount control surface The tolerance of the SB gap G is exceeded by the degree of accuracy alone.

Therefore, in a developing device equipped with a resin doctor blade, the SB gap G carries the developer when the doctor blade is fixed to the mounting portion of the developing frame regardless of the straightness of the coat amount regulating surface. It is desired to be within a predetermined range along the length of the body. In the first embodiment, by adopting the configuration described below, the doctor blade can be fixed to the mounting portion of the developing frame even when using a resin doctor blade having a coating amount regulating surface with low straightness accuracy. In this state, the gap between the developer carrier and the doctor blade should be within a predetermined range along the longitudinal direction of the developer carrier. Details are described below.

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

During the image forming operation (developing operation), developer pressure (hereinafter referred to as developer pressure) generated by the developer flow is applied to the doctor blade 36 . As the rigidity of the doctor blade 36 decreases, the doctor blade 36 tends to deform more easily when the agent pressure is applied to the doctor blade 36 during the image forming operation (developing operation), and the size of the SB gap G tends to fluctuate more easily. It is in. During the image forming operation (developing operation), the agent pressure is applied in the lateral direction of the doctor blade 36 (direction of 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), the rigidity of the doctor blade 36 in the lateral direction is increased, thereby reducing the deformation of the doctor blade 36 in the lateral direction. It is desirable to be strong against

As shown in FIG. 6, in the first embodiment, the doctor blade 36 is shaped like a plate from the viewpoint of mass productivity and cost. Further, 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 the length t2 in the thickness direction of the doctor blade 36 is equal to the length t2 of the doctor blade 36. It is smaller than the length t1 in the hand direction. As a result, the doctor blade 36 (single body) is configured to be easily deformed in a direction (arrow M direction in FIG. 6) perpendicular to the longitudinal direction (arrow N direction in FIG. 6) of the doctor blade 36 . Therefore, in the first embodiment, in order to correct the straightness of the coat amount regulating surface 36r, the doctor blade 36 is bent in the direction of arrow M in FIG. It is fixed to the blade attachment portion 41 of 30 . Details of a method of fixing the doctor blade 36 to the blade mounting portion 41 of the developing frame 30 (hereinafter referred to as a fixing method of the doctor blade 36) will be described later with reference to FIG.

Next, the rigidity of the doctor blade 36 (single body) will be described with reference to the schematic diagram of FIG. The rigidity of the doctor blade 36 (single body) is measured in a state where the doctor blade 36 is not fixed to the blade mounting portion 41 of the developing frame 30 .

As shown in FIG. 7, a concentrated load F1 is applied in the lateral direction of the doctor blade 36 to the central portion 36z of the doctor blade 36 in the longitudinal direction of the doctor blade 36. As shown in FIG. At this time, the rigidity of the doctor blade 36 (single body) is measured based on the deflection amount of the doctor blade 36 in the lateral direction at the central portion 36z of the doctor blade 36 .

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

Next, the rigidity of the development frame 30 (single body) will be described with reference to the schematic diagram of FIG. The rigidity of the development frame 30 (single body) is measured in a state where the doctor blade 36 is not fixed to the blade mounting portion 41 of the development frame 30 .

As shown in FIG. 8 , a concentrated load F1 is applied in the lateral direction of the blade mounting portion 41 to the 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 development frame 30 (single body) is measured based on the bending amount of the blade mounting portion 41 in the lateral direction at the central portion 41z of the blade mounting portion 41 .

For example, assume that a concentrated load F1 of 300 gf is applied in the lateral direction of the blade mounting portion 41 to the central portion 41z of the blade mounting portion 41 in the longitudinal direction of the blade mounting portion 41 . At this time, the bending amount in the lateral direction of the blade mounting portion 41 at the central portion 41z of the blade mounting portion 41 is 60 μm or less.

Assume that the central portion 36z of the doctor blade 36 and the central portion 41z of the blade mounting portion 41 of the developing frame 30 are each applied with the same concentrated load F1. At this time, the amount of bending of the central portion 36z of the doctor blade 36 is ten times or more the amount of bending of the central portion 41z of the blade mounting portion 41 . Therefore, the rigidity of the developing frame 30 (single body) is ten times or more greater than the rigidity of the doctor blade 36 (single body). Therefore, when the doctor blade 36 is attached to the blade mounting portion 41 of the developing frame 30 and the doctor blade 36 is fixed to the blade mounting portion 41 of the developing frame 30, the rigidity of the doctor blade 36 is reduced. The stiffness of the body 30 becomes dominant.

Further, the rigidity of the developing frame 30 (single body) is larger than the rigidity of the cover frame 40 (single body). Therefore, when the cover frame 40 is attached to the developing frame 30 and the cover frame 40 is fixed to the developing frame 30 , the rigidity of the developing frame 30 is higher than that of the cover frame 40 . become dominant.

(Fixing method of resin doctor blade)
Each step of the fixing method of the doctor blade 36 will be described with reference to the schematic diagrams of FIGS. 9 to 14. FIG. An external device (hereinafter simply referred to as device 100) performs each step of the method of fixing the doctor blade 36 described below.

First, the device 100 detects the outer shape of the coating amount regulation surface 36r of the doctor blade 36. As shown in FIG. Subsequently, the apparatus 100 determines the outer shape of the coating amount regulation surface 36r in the longitudinal direction of the coating amount regulation surface 36r, with the central portion of the coating amount regulation surface 36r (tip 36e3 of the doctor blade 36) as a reference. Recognize the straightness of 36r. In the process of fixing the doctor blade 36, a resin doctor blade corresponding to A3 size manufactured with the precision of a general resin molded product is used. Therefore, the device 100 recognizes that the straightness of the coating amount regulation surface 36r is about 300 μm to 500 μm. The apparatus 100 then causes the force applied to the doctor blade 36 to deflect at least a portion of the area of the doctor blade 36 corresponding to the maximum image area. Then, the apparatus 100 corrects the straightness of the coating amount regulation surface 36r to 50 μm or less (hereinafter referred to as a bending step).

Subsequently, the apparatus 100 determines a position for fixing the doctor blade 36, which has been bent in at least a part of the area corresponding to the maximum image area in the bending step, to the blade mounting portion 41 of the developing frame 30, and the SB gap G is set to a predetermined position. (hereinafter referred to as a positioning step). Subsequently, the apparatus 100 moves a portion of the area corresponding to the maximum image area of the doctor blade 36 with the portion of the area corresponding to the maximum image area of the doctor blade 36 flexed. It is fixed at a predetermined position of the mounting portion 41 (hereinafter referred to as a fixing step).

The apparatus 100 has a stand 103 for placing the doctor blade 36 (single body). In addition, the device 100 has five fingers 101 (101p1 to 101p5) for respectively gripping the gripping portions 37 (37p1 to 37p5) provided at five locations within the area corresponding to the maximum image area of the doctor blade 36. have. Each of the fingers 101 (101p1 to 101p5) is independently movable in the direction J in FIG. 9, and can move forward and backward in the direction J in FIG.

The apparatus 100 also has five cameras 102 (102p1 to 102p5) for respectively measuring the positions of the five tip portions 36e (36e1 to 36e5) included in the coating amount regulation surface 36r of the doctor blade 36. The cameras 102 (102p1 to 102p5) are arranged along the direction toward the tip 36e (36e1 to 36e5) of the doctor blade 36 (direction of arrow F in FIG. 9). The camera 102 (102p1 to 102p5) detects the outer shape of the coating amount regulation surface 36r of the doctor blade 36 by measuring the position of the tip portion 36e (36e1 to 36e5) of the doctor blade 36. FIG. Subsequently, the apparatus 100 determines the outer shape of the coating amount regulation surface 36r in the longitudinal direction of the coating amount regulation surface 36r, with the central portion of the coating amount regulation surface 36r (tip 36e3 of the doctor blade 36) as a reference. Recognize the straightness of 36r. 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, but a non-contact sensor may be used as a modification.

The doctor blade 36 is manufactured with the accuracy of a general resin molding. As described above, when a resin doctor blade corresponding to A3 size is manufactured with the precision of a general resin molded product, the straightness of the coat amount control surface is about 300 μm to 500 μm. It is assumed that the doctor blade 36 is a resin-made doctor blade corresponding to A3 size manufactured with the accuracy of a general resin molded product. In this case, when the doctor blade 36 is placed on the pedestal 103, the positions of the five tip portions 36e (36e1 to 36e5) of the doctor blade 36 are measured by the cameras 102 (102p1 to 102p5), and the positions are about 300 μm to 500 μm. will have a difference of On the other hand, 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.

Therefore, the straightness of the tip portions 36e1 to 36e5 of the doctor blade 36 (that is, the straightness of the coating amount regulating surface 36r) is determined in consideration of the allowable tolerance of the SB gap G, the mounting accuracy of the doctor blade 36 with respect to the developing frame 30, and the like. degree) must be corrected to 50 μm or less. In view of the fact that the accuracy of the straightness of the metal doctor blade is 20 μm or less by secondary cutting, it is more preferable to set the straightness of the coating amount regulation surface 36r of the resin doctor blade 36 to 20 μm or less. It is to correct.

Subsequently, details of a series of steps (bending step, positioning step, fixing step) of the fixing method of the doctor blade 36 will be described below.

(1) Bending process First, details of the bending process will be described with reference to the schematic diagram of FIG. 9 . The apparatus 100 holds the doctor blade 36 by gripping the gripping portions 37 (37p1-37p5) of the doctor blade 36 with the fingers 101 (101p1-101p5). Subsequently, the camera 102 (102p1 to 102p5) moves the tip portion 36e (36e1 to 36e5) of the doctor blade 36 while gripping the gripping portion 37 (37p1 to 37p5) of the doctor blade 36 with the fingers 101 (101p1 to 101p5). Measure the position of Thereby, the apparatus 100 detects the outer shape of the coating amount regulation surface 36r of the doctor blade 36. FIG. Next, the device 100 determines the outer shape of the coating amount regulation surface 36r in the longitudinal direction, with the central portion of the coating amount regulation surface 36r (tip 36e3 of the doctor blade 36) as a reference. Recognize the straightness of 36r.

Then, the device 100 moves each of the fingers 101 (101p1 to 101p5) in the J direction in FIG. As a result, the apparatus 100 applies a force to the doctor blade 36 via the grasping portion 37 of the doctor blade 36 grasped by the fingers 101 to bend at least a portion of the area corresponding to the maximum image area of the doctor blade 36 . Give. Thus, the gripping portion 37 of the doctor blade 36 serves as a force receiving portion for receiving the force applied to the doctor blade 36 by the apparatus 100 to deflect at least a portion of the area of the doctor blade 36 corresponding to the maximum image area. play the role of

As shown in FIG. 10, in the doctor blade 36 (single body), the central portion of the coating amount regulation surface 36r of the doctor blade 36 is greatly bent in the longitudinal direction of the doctor blade 36. As shown in FIG. Therefore, it is necessary to correct the straightness of the coating amount regulation surface 36r of the doctor blade 36 by reducing the difference in the positions of the tip portions 36e (36e1 to 36e5) of the doctor blade 36. FIG. Therefore, the positions of the tip portions 36e (36e1 to 36e5) of the doctor blade 36 are determined based on the results of measuring the positions of the tip portions 36e (36e1 to 36e5) of the doctor blade 36 (detected outer shape of the coating amount regulation surface 36r). so that the difference between Therefore, the apparatus 100 applies a force (also called a straightness correction force) to the doctor blade 36 to bend at least a part of the area corresponding to the maximum image area of the doctor blade 36, thereby reducing the coating amount. The straightness of the regulation surface 36r is corrected to 50 μm or less.

Subsequently, the device 100 grips the gripping portions 37 (37p1 to 37p5) of the doctor blade 36 placed on the mounting table 103 with the fingers 101 (101p1 to 101p5). Then, the device 100 moves each of the fingers 101 independently in the direction of arrow J in FIG. Or move backward. At this time, the apparatus 100 applies a force to the doctor blade 36 via the gripping portion 37 of the doctor blade 36 to deflect at least a portion of the area corresponding to the maximum image area of the doctor blade 36 .

In the example of FIG. 10, the apparatus 100 uses the outer shape of the tip portions 36e1 and 36e5 of the doctor blade 36 as a reference, and straightens the doctor blade 36 so that the outer shapes of the tip portions 36e2, 36e3, and 36e4 match the reference. It provides degree correction power. In the example of FIG. 10, the doctor blade 36 is used to bend at least a portion of the area corresponding to the maximum image area of the doctor blade 36 via three gripping portions 37 (37p2 to 37p4) out of five. receive power from the outside. Then, force applied to the doctor blade 36 via the gripping portions 37 (37p2 to 37p4) at three locations is used to correct the straightness of the coating amount regulation surface 36r with respect to the tip portions 36e2 to 36e4 of the doctor blade 36. A straightness correction force is applied in the direction of arrow I in FIG. At this time, a straightness correction force is applied to the coat amount regulation surface 36r, and at least a part of the area corresponding to the maximum image area of the doctor blade 36 is bent, thereby reducing the straightness of the coat amount regulation surface 36r of the doctor blade 36. A correction is made. In the example of FIG. 10, the shape of the coat amount regulation surface 36r of the doctor blade 36 is corrected from the coat amount regulation surface 36r1 to the coat amount regulation surface 36r2.

As a result, the straightness of the coating amount regulation surface 36r of the doctor blade 36 can be corrected to 50 μm or less. In the example of FIG. 10, the tip 36e1 and 36e5 of the doctor blade 36 are used as a reference for matching the outer shape of the tip 36e of the doctor blade 36 with the apparatus 100. A modified example in which the center portion of the amount restricting surface 36r) is also possible. In this modified example, the apparatus 100 uses the outer shape of the tip portion 36e3 of the doctor blade 36 as a reference, and straightens the doctor blade 36 so that the outer shapes of the tip portions 36e1, 36e2, 36e4, and 36e5 match the reference. Gives degree correction power.

In the first embodiment, in consideration of a realistic mass production process, the set value for correcting the straightness of the coating amount regulation surface 36r of the doctor blade 36 is set to about 20 μm to 50 μm, and applied to the tip 36e of the doctor blade 36. The magnitude of the straightness correction force is set to approximately 500 g. In general, the smaller the magnitude of the straightness correction force applied to the tip 36e of the doctor blade 36, the smaller the apparatus 100 can be made at low cost. However, if the magnitude of the straightness correction force applied to the tip portion 36e of the doctor blade 36 is too small with respect to the rigidity of the doctor blade 36, the straightness of the coating amount regulation surface 36r of the doctor blade 36 is corrected. I can't do it. Therefore, the magnitude of the straightness correction force applied to the tip portion 36 e of the doctor blade 36 is set based on the rigidity of the doctor blade 36 .

In the example of FIG. 9, an example in which the gripping portions 37 are provided at five locations on the doctor blade 36 has been described. The locations and number of blades 36 provided are not limited to this. Further, in the example of FIG. 9, an example in which the grasping portion 37 of the doctor blade 36 has a convex shape has been described, but the shape of the grasping portion 37 is not limited to this. As previously mentioned, in order for the apparatus 100 to apply a force (straightness correction force) to the doctor blade 36 to deflect at least a portion of the area corresponding to the maximum image area of the doctor blade 36, the fingers 101 are: It grips the gripping portion 37 of the doctor blade 36 . Therefore, as long as the fingers 101 can grip the gripping portion 37, the shape of the gripping portion 37 may be, for example, a concave shape, a grooved shape, a cutout shape, or a flat shape, in addition to the convex shape. or a combination of these shapes. Of the drawings in this specification, in the drawings showing the doctor blade 36, the grasping portion 37 of the doctor blade 36 is omitted except for FIGS.

(2) Positioning Process Subsequently, the details of the positioning process will be described with reference to the schematic diagrams of FIGS. 11 and 12. FIG. As shown in FIGS. 11 and 12 , the positioning process is performed while the developing sleeve 70 is supported by the sleeve supporting portion 42 of the developing frame 30 .

The fingers 101 (101p1 to 101p5) move the doctor blade 36 from the mounting table 103 while holding the doctor blade 36 in a state of being bent in the bending step (that is, a state in which the straightness of the coating amount regulation surface 36r is corrected). It is moved to the blade attachment portion 41 . The moving amount and moving direction of the fingers 101 (101p1 to 101p5) are preset by a program. Fingers 101 (101p1 to 101p5) are driven by actuators and operate according to preset programs.

Then, the device 100 moves the bent doctor blade 36 to the developing frame while the fingers 101 (101p1 to 101p5) grasp the grasping portions 37 of the bent doctor blade 36 in the bending step. 30 to the blade attachment portion 41 . Subsequently, the device 100 attaches the doctor blade 36 in a bent state to the blade attachment portion 41 . At this time, the doctor blade 36 in a bent state is in a state of being landed (also referred to as a state of contact) with the blade mounting surface 41s (see FIGS. 4 and 5) of the developing frame 30. As shown in FIG.

In FIG. 11, the gripping portions 37 (37p1 to 37p5) of the doctor blade 36, which is bent in the bending step, are held by the fingers 101 (101p1 to 101p5), and the doctor blade 36 is attached to the blade mounting surface 41s. It shows the landed state.

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 (that is, range) is set to about 60 μm in the range. Since the range of the tolerance of the SB gap G is thus severe, the SB gap G does not exceed the tolerance of the SB gap G simply by landing the doctor blade 36 on the blade mounting surface 41s of the developing frame 30. It is unlikely that the range falls within the considered SB gap G adjustment range (ie, the SB gap G adjustment range includes the SB gap G target value). Therefore, by determining the position where the doctor blade 36 is fixed to the blade mounting surface 41s of the developing frame 30 so that the SB gap G is within the tolerance range, the SB gap G is within the adjustment range of the SB gap G. should be adjusted to fit.

The apparatus 100 has five cameras 104 for respectively measuring the positions of five tip portions 36e (36e1 to 36e5) of the doctor blade 36 which is landed on the blade mounting surface 41s of the developing frame 30 by the finger 101. (104p1 to 104p5). The cameras 104 (104p1 to 104p5) are arranged along the direction toward the tip 36e (36e1 to 36e5) of the doctor blade 36 (direction of arrow F in FIG. 11). 36e5) can be measured. In the first embodiment, an example in which the positions of the tip portions 36e (36e1 to 36e5) of the doctor blade 36 are measured by the cameras 104 (104p1 to 104p5) will be described below. It can be an example.

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 with the developing sleeve 70 supported by the sleeve supporting portion 42 of the developing frame 30, the doctor blade 36 mounted on the blade mounting portion 41 of the developing frame 30, and the cover frame 40 It is performed in a state fixed to the developing frame 30 . Also, in measuring the size of the SB gap G, a light source (for example, an LED array, a light guide, etc.) is inserted into the developing chamber 31 along the longitudinal direction of the developing chamber 31 . A light source inserted into the developing chamber 31 irradiates the SB gap G from within the developing chamber 31 with light. Then, the cameras 104 (104p1 to 104p5) pick up images of light rays emitted from the SB gap G to the outside of the developing frame 30. FIG. At this time, the cameras 104 (104p1 to 104p5) capture the position 70a (70a1 to 70a5) where the developing sleeve 70 is closest to the doctor blade 36 on the surface of the developing sleeve 70 and the tip portion 36e (36e1 to 36e5) of the doctor blade 36. read. Subsequently, the device 100 converts the pixel values from the image data generated by reading with the cameras 104 (104p1 to 104p5) into distances, and calculates the size of the SB gap G. FIG. If the calculated size of the SB gap G is not within the predetermined range, the device 100 adjusts the SB gap G.

Details of the method for adjusting the SB gap G will now be described with reference to the schematic diagram of FIG. The device 100 moves the fingers 101 in the direction of arrow K shown in FIG. The direction of 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 supporting portion 42 of the developing frame 30 is adjusted (that is, the direction defining the SB gap G). be. 12 indicates the direction in which the doctor blade 36 approaches or moves away from the developing sleeve 70 supported by the sleeve supporting portion 42 of the developing frame 30. As shown in FIG. As a result, the relative position of the tip portion 36e (36e1 to 36e5) of the doctor blade 36 with respect to the position 70a (70a1 to 70a5) where the developing sleeve 70 is closest to the doctor blade 36 on the surface of the developing sleeve 70 is adjusted.

For example, assume that the SB gap G calculated at the initial position where the doctor blade 36 is landed on the blade mounting surface 41s of the developing frame 30 is 350 μm. On the other hand, it is assumed that the adjustment range of the SB gap G is 300 μm±30 μm, and the maximum allowable tolerance of the SB gap G is 60 μm. In this case, at the initial position where the doctor blade 36 is landed 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, the finger 101 grips the gripping portion 37 of the doctor blade 36 and moves the doctor blade 36 in the direction of the arrow K shown in FIG. 36 is translated.

Then, the position 70a (70a1 to 70a5) closest to the doctor blade 36 translated by the camera 104 and the finger 101 and the distal end portion 36e (36e1 to 36e5) of the doctor blade 36 translated by the finger 101 are read. Subsequently, the device 100 recalculates the SB gap G with respect to the doctor blade 36 translated by the finger 101 .

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 device 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 is within the adjustment range of the SB gap G (300 μm±30 μm) The adjustment of the SB gap G described above is repeated until . By fixing the doctor blade 36 to the blade mounting portion 41 of the developing frame 30 in a state in which the straightness of the coating amount regulation surface 36r is corrected to 50 μm or less in this manner, the size of the SB gap G is set to SB gap. It can be put in the adjustment range of G.

Here, a more preferable embodiment for adjusting the SB gap G with higher accuracy will be described with reference to the schematic diagrams of FIGS. 13 and 14. FIG. In this embodiment, the straightness of the surface of the developing sleeve 70 is taken into consideration in addition to the straightness of the coating amount regulation surface 36r of the doctor blade 36, so that the SB gap G can be adjusted with higher accuracy.

Since the sleeve tube forming the outer shell of the developing sleeve 70 is made of metal, the surface straightness of the developing sleeve 70 can be made highly accurate to ±15 μm or less by secondary cutting the sleeve tube. However, the straightness of ±15 μm of the developing sleeve 70 is perceived as if the outer diameter of the developing sleeve 70 apparently fluctuates by ±15 μm when the developing sleeve 70 is rotated in actual use. In order to minimize the influence on the SB gap G caused by the accuracy of the straightness of the coating amount regulation surface 36r of the doctor blade 36 in the rotating state of the developing sleeve 70, the SB gap G is adjusted while the developing sleeve 70 is rotated. It is useful to measure

FIG. 13 shows the position of the tip 36e of the doctor blade 36 when the developing sleeve 70 is stopped. FIG. 13A shows a state in which the SB gap G is adjusted while the developing sleeve 70 is stopped at a position far from the doctor blade 36 . On the other hand, FIG. 13B shows a state in which the SB gap G is adjusted while the developing sleeve 70 is stopped at a position close to the doctor blade 36 . 14 shows the position of the tip 36e of the doctor blade 36 while the developing sleeve 70 is rotating.

As shown in FIGS. 13A and 13B, the size of the SB gap G is the same between FIGS. 13A and 13B, but between FIGS. The position of the tip 36e of the doctor blade 36 is different. Also, 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 near the doctor blade 36 There is a difference in the phase of As a result, even if the developing sleeve 70 with the same accuracy and the doctor blade 36 with the same accuracy are used and the adjustment value of the SB gap G is the same, the doctor blade 36 has a different position of the tip portion 36e of the developing device. It will be fixed to the blade attachment portion 41 of the frame 30 . This means that manufacturing variations are allowed in the manufacturing of the developing device 3 . Therefore, by adjusting the SB gap G while rotating the developing sleeve 70, variations in manufacturing are reduced.

When the developing sleeve 70 is rotated, due to the straightness of the surface of the developing sleeve 70, a runout (hereinafter referred to as a runout of the outer diameter of the developing sleeve 70) occurs due to the coming and going of the outer diameter line of the developing sleeve 70. . As shown in FIG. 14, the outer diameter line of the developing sleeve 70 is centered on the center line 73L0 of the deflection of the outer diameter of the developing sleeve 70, the outer diameter line 73L1 of the developing sleeve 70, and the outer diameter line 73L2 of the developing sleeve 70. can be perceived as going back and forth between Therefore, by measuring the deflection of the outer diameter of the developing sleeve 70, the center of the deflection of the outer diameter of the developing sleeve 70 can be detected. Therefore, the center line 73L0 of the deflection of the outer diameter of the developing sleeve 70 is detected, and the size of the SB gap G is measured from the center line 73L0 of the deflection of the outer diameter of the developing sleeve 70. FIG. As a result, the tip of the doctor blade 36 is caused by the difference in the phase of the developing sleeve 70 when stopped at a position far from the doctor blade 36 and the phase of the developing sleeve 70 when stopped at a position close to the doctor blade 36. Variation in the position of the portion 36e can be suppressed.

Therefore, by using the developing sleeve 70 with the same accuracy and the doctor blade 36 with the same accuracy, while rotating the developing sleeve 70, the position of the tip portion 36e of the doctor blade 36 can be adjusted to the same position by using the same adjusted value of the SB gap G. position can be reproduced. As a result, manufacturing variations can be reduced.

As described above, the straightness of the surface of the developing sleeve 70 is ±15 μm or less. , the straightness of the surface of the developing sleeve 70 must be considered. Therefore, in the positioning process, the finger 101 moves the doctor blade 36 parallel to the surface of the developing sleeve 70 in a direction to bring the doctor blade 36 closer to the surface of the developing sleeve 70, and the doctor blade 36 is landed on the blade mounting surface 41s. is performed.

The apparatus 100 applies a straightness correction force for correcting the straightness of the coating amount regulation surface 36r to the doctor blade 36 via the grasping portion 37 of the doctor blade 36 before landing the doctor blade 36 on the blade attachment surface 41s. 36. That is, the device 100 corrects the straightness of the coating amount regulation surface 36r to 50 μm or less in advance before the doctor blade 36 is landed on the blade attachment surface 41s. Then, the apparatus 100 lands the doctor blade 36 with the straightness of the coating amount regulation surface 36r corrected to 50 μm or less on the blade attachment surface 41s.

Subsequently, the device 100 moves the developing sleeve 70 to keep the SB gap G within a predetermined range (that is, the adjustment range of the SB gap G) in a state where the doctor blade 36 is fixed to the blade mounting portion 41 . An adjusting force is applied to the doctor blade 36 via the grasping portion 37 of the doctor blade 36 to adjust the relative position of the coating amount regulation surface 36r of the doctor blade 36 with respect to the . That is, the finger 101 is positioned in the maximum image area of the doctor blade 36 so that the SB gap G measured by the camera 104 is within the adjustment range of the SB gap G in a state in which the doctor blade 36 is in contact with the blade attachment surface 41s. At least a portion of the corresponding area is deflected. At this time, at least a portion of the area corresponding to the maximum image area of the doctor blade 36 is flexed 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 . state.

As a result, the SB gap G can be adjusted with higher accuracy in consideration of not only the straightness of the coating amount regulation surface 36r of the doctor blade 36 but also the straightness of the surface of the developing sleeve 70. FIG. Then, it becomes possible to adjust the relative position of the coating amount regulation 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 that case, after the relative position of the coating amount regulation 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 in the longitudinal direction of the developing sleeve 70, the doctor blade 36 is fixed by a fixing step to be described later. It is fixed to the mounting portion 41 .

If the straightness of the surface of the developing sleeve 70 is of a higher precision (for example, ±5 μm or less), the straightness of the coating amount regulation surface 36r should be taken into consideration when adjusting the SB gap G. Well, it is not essential to consider even the straightness of the surface of the developing sleeve 70 . Similarly, when the SB gap G has a large latitude, the straightness of the coating amount regulation surface 36r of the doctor blade 36 is considered when adjusting the SB gap G, but the straightness of the surface of the developing sleeve 70 It is not essential to consider

(3) Fixing Step Subsequently, 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, in the fixing step, the doctor blade in a bent state in the bending step is held at a predetermined position of the blade mounting portion 41 of the developing device frame 30 determined in the positioning step. 36 is on the ground.

In the first embodiment, before the doctor blade 36 lands on the blade mounting surface 41s of the developing frame 30, the apparatus 100 applies the adhesive over substantially the entire area corresponding to the maximum image area with respect to the blade mounting surface 41s. Apply A. Then, in the bending process, the doctor blade 36 in a bent state 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 coating amount regulation surface 36r corrected to 50 μm or less.

That is, in the first embodiment, of the area corresponding to the maximum image area of the doctor blade 36, the area bent to correct the straightness of the coating amount regulation surface 36r is fixed to the blade mounting portion 41. will be As a result, of the area corresponding to the maximum image area of the doctor blade 36, the area bent to correct the straightness of the coating amount regulation surface 36r returns from the bent state to the original state before bending. You can restrain yourself from trying.

On the other hand, depending on the shape of the blade mounting portion 41, there may be areas where it is difficult for the device 100 to apply the adhesive A to the blade mounting surface 41s. In such a case, if the area subjected to the force to deflect at least a portion of the area corresponding to the maximum image area of the doctor blade 36 is fixed to the blade mounting portion 41 by adhesive A, the blade mounting surface It is assumed that the adhesive A may not be applied to a part of 41s.

Therefore, the adhesive A is applied over substantially the entire area corresponding to the maximum image area on the blade mounting surface 41s means that the following conditions are satisfied. 95 of the area corresponding to the maximum image area in the longitudinal direction of the blade mounting surface 41s, including the area bent to correct the straightness of the coat amount control surface 36r, out of the area corresponding to the maximum image area of the doctor blade 36; % or more of the adhesive A is applied.

As for the selection of the adhesive A, it is necessary that the adhesive strength is such that the doctor blade 36 does not separate from the blade mounting 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 the drop test. there is no problem. Therefore, 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 the adhesive A, the better.

Next, the film thickness of the adhesive A applied to the blade mounting surface 41s of the developing frame 30 will be described. 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 must be interposed between the doctor blade 36 and the blade mounting surface 41s of the developing frame 30. Become. Therefore, a film 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 Thickness must be considered.

Regarding the relationship between the film thickness of the adhesive A and the magnitude of the breaking load of the portion bonded with the adhesive A, the larger the amount of the adhesive A, the greater the bonding strength of the 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. The strength is set to 10 kgf or more. Therefore, in order to ensure that the adhesive strength of the adhesive A is 10 kgf or more, the film thickness of the adhesive A applied to the blade mounting surface 41s of the developing frame 30 should be 20 μm or more.

Next, the relationship between the thickness of the adhesive A to be applied and the magnitude of dimensional variation of the adhesive A in the thickness direction will be described. In general, as the film thickness of the adhesive A increases, the dimensional variation in the thickness direction of the adhesive A occurs due to shrinkage of the adhesive A when the adhesive A hardens. On the other hand, the magnitude of the dimensional variation in the thickness direction of the adhesive A when the film thickness of the adhesive A is 150 μm is greater than the dimensional variation in the thickness direction of the adhesive A when the film thickness of the adhesive A is 30 μm. It is only about 8 μm larger than the size. If the size of the dimensional variation in the thickness direction of the adhesive A is about 8 μm, the effect of the dimensional variation in the direction perpendicular to the thickness direction of the adhesive A (that is, the direction defining the SB gap G) can be ignored. level. Therefore, the upper limit of the film thickness of the adhesive A to be applied to the blade mounting surface 41s of the developing frame 30 is not determined by the shrinkage of the adhesive A, but rather depends on individual production factors such as the curing time and cost of the adhesive A. It should be determined by the requirements.

In the first embodiment, an example in which the adhesive A is applied to the blade mounting portion 41 side has been described. Alternatively, the coating may be applied to both the side and the doctor blade 36 side. As for the timing of applying the adhesive A to the blade mounting portion 41 side, prior to the start of the positioning process (more preferably in parallel with the bending process), a series of steps of the fixing method of the doctor blade 36 can be performed. It is possible to shorten the total time required for That is, in this example, it means a series of steps of applying the adhesive A to the blade mounting portion 41 of the developing frame 30 while correcting the straightness of the coating amount regulation surface 36r. Therefore, in the first embodiment, the step of applying the adhesive A to the blade mounting portion 41 side of the developing frame 30 is performed prior to the start of the positioning step.

When the doctor blade 36 is fixed with the adhesive A, in the positioning process, if the adhesive A hardens during the adjustment of the SB gap G with respect to the doctor blade 36 that has landed on the blade mounting surface 41s, then the SB Gap G cannot be adjusted. Therefore, the adjustment of the SB gap G must be completed before the adhesive A hardens. The curing time of the adhesive A is determined based on the material of the adhesive A and the amount of the adhesive A applied. Therefore, the curing time of adhesive A can be predicted to some extent. Therefore, the number of times the SB gap G can be repeatedly adjusted until the adhesive A hardens is determined in advance from the time required for each adjustment of the SB gap G. FIG. Therefore, within the range of the number of times, the adjustment of the SB gap G can be repeated because the adhesive A has not yet hardened.

If repeating the adjustment of the SB gap G is prioritized over shortening the total time required for a series of steps of fixing the doctor blade 36, the adhesive A is applied after the positioning step is completed. may be applied to the blade mounting portion 41 side. In the modified example, in the positioning process, the device 100 receives information on the position at which the doctor blade 36 is fixed to the blade mounting surface 41s of the developing device frame 30, which is determined from the adjustment of the SB gap G. stored in memory. After the positioning process is completed, the apparatus 100 performs a process 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 moves the doctor blade 36 in the bent state in the bending step based on the information on the fixed position of the doctor blade 36 stored in the memory. is landed on the blade mounting surface 41 s of the developing frame 30 . Then, after the doctor blade 36 in a bent state lands on the blade mounting surface 41s, the device 100 may start the fixing process described above.

After the adjustment of the SB gap G is completed, the doctor blade 36 and the blade attachment portion 41 of the developing frame 30 are kept in a desired adhesive strength until the adhesive A is cured. 36 must be kept in close contact with the blade mounting portion 41 . In order to adhere 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 when the gap between the doctor blade 36 and the blade mounting portion 41 is large, even if the adhesive A is interposed in the gap, the bonding strength is weakened.

Therefore, in order to bring the doctor blade 36 into close contact with the blade mounting portion 41, it is necessary to apply a constant load. Specifically, in the apparatus 100, the doctor blade 36 is placed on the blade mounting surface 41s of the developing frame 30, and a weight having a predetermined weight is dropped on the doctor blade 36 to move the doctor blade 36 to the blade position. A load is applied to bring the mounting portion 41 into close contact. In order to obtain a sufficient adhesive strength, the finger 101 is held in contact with the doctor blade 36 against the blade mounting portion 41 under such a load for a period of time until the adhesive A is sufficiently hardened. must continue to hold the doctor blade 36. For example, if the curing time of the adhesive A is 15 seconds, the load for bringing the doctor blade 36 into close contact with the blade mounting portion 41 may be set to be applied for 20 seconds with a margin.

After the doctor blade 36 is completely adhered to the blade mounting portion 41 , the device 100 lifts the weight to remove the load from the doctor blade 36 . Then, the device 100 operates the fingers 101 (101p1-101p5) to release the fingers 101 (101p1-101p5) from the doctor blade 36, and then moves the fingers 101 (101p1-101p5) to the preparation positions for the next operation. to move.

The details of the steps of the method for fixing the doctor blade 36 have been described above. In this series of fixing methods described above, the apparatus 100, before landing the doctor blade 36 whose accuracy of the coating amount regulation surface 36r is about 300 μm to 500 μm on the blade mounting surface 41s, corrects the straightness of the coating amount regulation surface 36r. is corrected in advance to 50 μm or less. As a result, even if the doctor blade 36 made of resin whose straightness accuracy of the coating amount regulation surface 36r is low is used, the SB gap G is reduced to SB An example in which the gap G can be within the adjustment range has been described. In this example, separate devices 100 are provided with a function for performing the bending process and a function for performing the positioning process. That is, the doctor blade 36 (single body) is placed on the table 103 of the apparatus 100 for performing the bending process, which is a separate apparatus from the apparatus 100 for performing the positioning process. The device 100 for performing the bending process is for bending at least a part of the area corresponding to the maximum image area of the doctor blade 36 in a state where the doctor blade 36 (single body) is placed on the table 103. A force was applied to the doctor blade 36 .

On the other hand, a modification in which one device 100 has a function for performing the bending process and a function for performing the positioning process is also conceivable. In this modified example, the one device 100, before landing the doctor blade 36, whose precision of the coating amount regulation surface 36r is about 300 μm to 500 μm, on the blade mounting surface 41s, makes the coating amount regulation surface 36r straight. The degree is not corrected in advance to 50 μm or less. Instead, the one device 100 is configured so that the SB gap G is within the adjustment range of the SB gap G after the doctor blade 36 is landed on the blade mounting surface 41s and before the adhesive A is cured. at least a portion of the area corresponding to the maximum image area of the doctor blade 36 is deflected. That is, in this modified example, while the doctor blade 36 is fixed to the blade mounting surface 41s, the maximum image area of the doctor blade 36 is adjusted to keep the SB gap G within a predetermined range (that is, the adjustment range of the SB gap G). means a series of steps of bending at least a portion of the region corresponding to . As a result, even if the doctor blade 36 made of resin whose straightness accuracy of the coating amount regulation surface 36r is low is used, the SB gap G is reduced to SB It can be put within the adjustment range of the gap G.

However, as described above, when a resin doctor blade corresponding to A3 size is manufactured with the precision of a general resin molded product, the straightness of the coating amount control surface is about 300 μm to 500 μm. For this reason, it is preferable for the device 100 to previously correct the straightness of the coating amount regulation surface 36r to 50 μm or less before the doctor blade 36 lands on the blade mounting surface 41s. This is because the adjustment of the SB gap G is performed in a state in which the straightness of the coating amount regulation surface 36r is corrected to 50 μm or less. This is because the adjustment time is shortened compared to the case where the adjustment is performed. In other words, the time required for the process performed with the doctor blade 36 in contact with the blade mounting surface 41s (the time for adjusting the SB gap G) is shortened. can be set shorter. Further, the takt time is shorter when the function for performing the bending process and the function for performing the positioning process are provided in separate devices 100 compared to the case where one device 100 is provided with the function. can generally be shortened, which is advantageous from the viewpoint of mass productivity.

Next, the deformation of the doctor blade 36 due to the agent pressure generated from the flow of the developer being applied to 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 in a cross section perpendicular to the rotation axis of the developing sleeve 70 (cross section H in FIG. 2). 15 shows the configuration of the vicinity of the doctor blade 36 fixed with the adhesive A to the blade mounting portion 41 of the developing frame 30. As shown in FIG.

As shown in FIG. 15, a line connecting the closest position of the doctor blade 36 to the developing sleeve 70 on the coat amount regulating surface 36r and the center of rotation of the developing sleeve 70 is defined as the X axis. At this time, the doctor blade 36 has a long length in the X-axis direction and a high rigidity in the cross section in the X-axis direction. Further, 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 device frame 30 located near the developer guide portion 35 is small. . As described above, in the first embodiment, the rigidity of the developing frame 30 (single body) is ten times or more the rigidity of the doctor blade 36 (single body). Therefore, when the doctor blade 36 is fixed to the blade mounting portion 41 of the developing frame 30 , the rigidity of the developing frame 30 is dominant with respect to the doctor blade 36 . As a result, during the image forming operation (developing operation), the amount of displacement (maximum amount of deflection) of the coating amount regulation surface 36r of the doctor blade 36 when the doctor blade 36 receives the developer pressure is equal to the amount of displacement of the developing frame 30. (maximum amount of deflection).

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 . Thereafter, even when the doctor blade 36 defines 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 defining the SB gap G) is defined as the Y-axis direction, the developer pressure in the Y-axis direction is applied to the blade mounting surface 41s of the developing frame 30. perpendicular to That is, the agent pressure in the Y-axis direction is a force in the direction of peeling off the doctor blade 36 from the blade mounting surface 41s. Therefore, the bonding force of the adhesive A must be sufficiently large against the agent pressure in the Y-axis direction. Therefore, in the first embodiment, the adhesion of the adhesive A to the blade mounting surface 41s is considered in consideration of the adhesive force of the adhesive A and the force that tends to separate the doctor blade 36 from the blade mounting surface 41s due to the pressure of the agent. The area and coating thickness are optimized. Further, in the first embodiment, the cross-sectional area T2 of the wall portion 30a of the developing frame 30 is sufficiently large with respect to the developer pressure in the Y-axis direction that the developer guide portion 35 receives. It is possible to suppress the deformation of the doctor blade 36 due to the developer pressure during (developing operation).

Next, the deformation of the doctor blade 36 due to 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. Examples of heat generated during the developing operation include heat generated when the rotation shaft of the developing sleeve 70 and the bearing 71 rotate, heat generated when the rotation shaft 33a of the first conveying screw 33 and the bearing member rotate, and the SB gap G. There is heat generated when the developer passes through. The temperature around the developing device 3 changes due to the heat generated during the image forming operation (developing operation), and the temperatures of the doctor blade 36, the developing frame 30, and the cover frame 40 also change.

On the other hand, if the coefficient of linear expansion α1 of the resin forming the doctor blade 36 and the coefficient of linear expansion α2 of the resin forming the developing device frame 30 are different, the difference in the coefficients of linear expansion causes a difference in the amount of deformation due to temperature change. . As described above, in the first embodiment, the method of fixing the doctor blade 36 to the blade mounting portion 41 of the developing frame 30 over substantially the entire area corresponding to the maximum image area with the adhesive A is adopted. ing. Further, if there is a large difference between the thermal linear expansion coefficient α2 of the resin forming the developing device frame 30 and the thermal linear expansion coefficient α1 of the resin forming the doctor blade 36, the following problems arise when the temperature changes. . That is, when the temperature changes, the deformation amount (expansion amount) of the doctor blade 36 due to the temperature change differs from the deformation amount (expansion amount) of the developing frame 30 due to the temperature change.

For example, at least the first region, the second region, and the third region within the region corresponding to the maximum image region of the doctor blade 36 with respect to the blade mounting surface 41s (for example, both ends of the region corresponding to the maximum image region of the doctor blade 36) 3 or more points including the part and the center part). In this case, since the amount of thermal expansion differs between the central portion and both end portions of the doctor blade 36, the doctor blade 36 is flexed to a large extent, and there is a risk that the doctor blade 36 will be largely warped. As a result, even if the SB gap G is adjusted with high precision when determining the position where the doctor blade 36 is attached to the blade mounting surface 41s of the developing frame 30, temperature changes during the image forming operation (developing operation) cause The size of the SB gap G will be changed.

In the first embodiment, since the doctor blade 36 is fixed to the blade mounting surface 41s over substantially the entire area corresponding to the maximum image area, the SB caused by the temperature change during the image forming operation (developing operation) Variation in the size of the gap G must be suppressed.

As shown in FIG. 16, the amount of elongation of the doctor blade 36 due to temperature change is H [μm], and the elongation amount of the blade mounting surface 41s of the blade mounting portion 41 of the developing frame 30 due to temperature change is I [μm]. It is also assumed that the linear expansion coefficient α1 of the resin forming the doctor blade 36 and the linear expansion coefficient α2 of the resin forming the developing frame 30 are different. In this case, the amount of deformation of the developing frame 30 and the doctor blade 36 due to temperature changes is different due to the difference in the coefficient of linear expansion. 16 will be deformed in the direction of arrow J. The deformation of the doctor blade 36 in the direction of arrow J in FIG. 16 is hereinafter referred to as deformation of the doctor blade 36 in the warp direction. Deformation of the doctor blade 36 in the direction of warp leads to variation in the size of the SB gap G. In order to suppress variations in the size of the SB gap G caused by heat, the coefficient of linear expansion α2 of the resin forming the sleeve support portion 42 and the blade mounting portion 41 of the development frame 30 (single body) and the doctor blade 36 Each of the coefficients of linear expansion α1 of the resin constituting the (single substance) is related.

Here, 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 device frame 30 having the sleeve supporting portion 42 and the blade mounting portion 41 is hereinafter referred to as the linear expansion coefficient Call the difference α2-α1. A change in the maximum amount of deflection of the doctor blade 36 due to the linear expansion coefficient difference α2-α1 will be described using Table 1. In a state where the doctor blade 36 was fixed to the blade mounting portion 41 of the developing frame 30 over substantially the entire area corresponding to the maximum image area, a temperature change from normal temperature (23° C.) to high temperature (40° C.) was applied. The maximum amount of deflection of the doctor blade 36 was measured.

The coefficient of linear expansion of the resin forming the developing frame 30 having the sleeve supporting portion 42 and the blade mounting portion 41 is α2 [m/°C], and the coefficient of linear expansion of the resin forming the doctor blade 36 is α1 [m/°C]. do. Table 1 shows the results of measuring the maximum amount of deflection of the doctor blade 36 while changing the parameter of the linear expansion coefficient difference α2-α1.

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 variation of the SB gap G caused by heat is generally suppressed to ±20 μm or less. There is a need. Therefore, in Table 1, when the absolute value of the maximum amount of deflection of the doctor blade 36 is 20 μm or less, the maximum amount of deflection is set to “O”, and when the absolute value of the maximum amount of deflection of the doctor blade 36 is greater than 20 μm. , the maximum amount of deflection is shown as "x".

As can be seen from Table 1, in order to suppress the fluctuation amount of the SB gap G caused by heat to ±20 μm or less, it is necessary to satisfy the following relational expression (Equation 1) for the linear expansion coefficient difference α2−α1. There is
(Formula 1)
−0.45×10 ⁻⁵ [m/°C]≦α2−α1≦0.55×10 ⁻⁵ [m/°C]

Therefore, the developing frame 30 is configured such that the linear expansion coefficient difference α2-α1 is −0.45×10 ⁻⁵ [m/° C.] or more and 0.55×10 ⁻⁵ [m/° C.] or less. The resin and the resin constituting the doctor blade 36 may be selected. As the resin constituting the developing frame 30 and the resin constituting the doctor blade 36, by selecting resins such that the linear expansion coefficient difference α2-α1 satisfies (Equation 1), the SB gap G caused by heat can be suppressed to ±20 μm or less. More preferably, the linear expansion coefficient difference α2-α1 is zero. In order to make the linear expansion coefficient difference α2−α1 zero, the resin forming the developing device frame 30 and the resin forming the doctor blade 36 should be the same.

In addition, since the cover frame 40 is fixed to the developing frame 30, if the amounts of deformation of the developing frame 30 and the cover frame 40 due to temperature changes are different, the deformation of the cover frame 40 in the warp direction is SB This leads to variations in the size of the gap G. As a result, even if the SB gap G is adjusted with high precision in the positioning process of the doctor blade 36, the size of the SB gap G may fluctuate due to temperature changes in the image forming operation (developing operation). .

In order to suppress variations in the size of the SB gap G due to temperature changes, the linear expansion coefficient α2 of the resin forming the sleeve support portion 42 and the blade mounting portion 41 of the developing frame 30 (single body) and the cover frame Each linear expansion coefficient α3 of the resin forming the body 40 (single body) is related. As described above, it is necessary to suppress the variation of the SB gap G due to heat to ±20 μm or less. The coefficient of linear expansion of the resin forming the developing frame 30 having the sleeve supporting portion 42 and the blade mounting portion 41 is α2 [m/°C], and the coefficient of linear expansion of the resin forming the cover frame 40 is α3 [m/°C]. and

Here, the difference between the linear expansion coefficient α3 of the resin forming the cover frame 40 and the linear expansion coefficient α2 of the resin forming the developing device frame 30 having the sleeve support portion 42 and the blade mounting portion 41 is hereinafter referred to as the linear expansion coefficient Call the difference α3-α2. Similar to Table 1, this linear expansion coefficient difference α3-α2 must satisfy the following relational expression (Equation 2).
(Formula 2)
−0.45×10 ⁻⁵ [m/°C]≦α3−α2≦0.55×10 ⁻⁵ [m/°C]

Therefore, the development frame 30 is configured such that the linear expansion coefficient difference α3-α2 is −0.45×10 ⁻⁵ [m/° C.] or more and 0.55×10 ⁻⁵ [m/° C.] or less. The resin and the resin forming the cover frame 40 may be selected. As the resin constituting the developing frame 30 and the resin constituting the cover frame 40, by selecting resins such that the linear expansion coefficient difference α3-α2 satisfies (Equation 2), the SB gap caused by heat is reduced. The variation of G can be suppressed to ±20 μm or less. More preferably, the linear expansion coefficient difference α3-α2 is zero. In order to make the linear expansion coefficient difference α3-α2 zero, the resin forming the developing frame 30 and the resin forming the cover frame 40 should be the same.

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

In general, many resin molded products have weaker wear resistance than metal molded products. Factors related to the wear resistance of the doctor blade 36 include the agent pressure applied to the doctor blade 36 . In selecting the resin that constitutes the doctor blade 36, it is generally known that the higher the surface hardness of the resin, the more excellent the abrasion resistance.

Therefore, in consideration of abrasion resistance, a resin having a surface hardness of 100 or more on the Rockwell hardness (JIS K7202-2) L scale is selected as the resin constituting the doctor blade 36 . Thereby, abrasion of the doctor blade 36 during the image forming operation (developing operation) can be suppressed. The doctor blade 36 made of such a resin causes only wear of 10 μm or less even in a durability test equivalent to about 500,000 sheets. As the surface hardness of the doctor blade 36 increases, the wear resistance of the doctor blade 36 improves, but 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 agents such as glass fibers. When a resin having such a high surface hardness is molded with a mold, the reinforcing agent added to the resin damages the mold. Therefore, if a certain amount or more of the reinforcing agent is added to the resin, mass productivity of the doctor blade 36 cannot be maintained. Therefore, by selecting a resin having a surface hardness of 100 or less on the Rockwell hardness (JIS K7202-2) M scale as the resin constituting the doctor blade 36, it has been found that the mass productivity of the doctor blade 36 can be ensured. ing.

In the first embodiment, considering both wear resistance and mass productivity of the doctor blade 36, the doctor blade 36 has a Rockwell hardness L scale of 100 or more and a Rockwell hardness M scale of 100 or less. It is molded from a resin with a surface hardness of . Examples of resins having a surface hardness with a Rockwell hardness L scale of 100 or more and a Rockwell hardness M scale of 100 or less include the following. For example, there is a resin (hereinafter referred to as resin X) containing polyphenylene ether (PPE) and polystyrene (PS) as base materials and containing 30% by weight or more and 35% by weight or less of a reinforcing agent. Further, for example, a resin (hereinafter referred to as resin Y) containing polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) as base materials and containing 20% by weight or more and 30% by weight or less of a reinforcing agent can be used.

Therefore, it is assumed that "Resin X" and "Resin Y" are selected as the resin constituting the doctor blade 36 in consideration of both wear resistance and mass productivity of the doctor blade 36. FIG. In this case, the developing frame 30 is configured so that the difference between the linear expansion coefficient α2 of the developing frame 30 and the linear expansion coefficient α1 of the doctor blade 36 (linear expansion coefficient difference α2−α1) satisfies the above-mentioned (formula 1). It is sufficient to select a resin that

When "Resin X" is selected as the resin constituting the doctor blade 36, and "Resin X" or "Resin Y" is selected as the resin constituting the developing frame 30, the linear expansion coefficient difference α2-α1 is as described above. (Formula 1) is satisfied. Further, when "resin Y" is selected as the resin constituting the doctor blade 36, if "resin X" or "resin Y" is selected as the resin constituting the developing frame 30, the linear expansion coefficient difference α2-α1 is It satisfies the above-mentioned (Equation 1).

On the other hand, when "resin X" is selected as the resin forming the developing device frame 30, "resin X" or "resin Y" may be selected as the resin forming the cover frame 40. FIG. 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 (formula 2). Further, when "resin Y" is selected as the resin constituting the developing frame 30, if "resin X" or "resin Y" is selected as the resin constituting the cover frame 40, the linear expansion coefficient difference α2-α3 satisfies the above-described (formula 2).

As described above, in the first embodiment, the doctor blade 36 whose straightness accuracy of the coat amount control surface 36r is the accuracy of a general resin molded product is used. Then, a portion of the area corresponding to the maximum image area of the doctor blade 36 is deflected to correct the straightness of the coating amount regulation surface 36r, and the doctor blade 36 substantially covers the entire area corresponding to the maximum image area. It is fixed to the blade mounting surface 41s over the entire length. With such a configuration, even if a resin doctor blade compatible with A3 size having a low straightness accuracy of the coating amount regulation surface 36r is used, the SB gap G is in the range of about 300 μm±30 μm along the longitudinal direction of the developing sleeve (i.e. , SB gap G adjustment range).

Further, in the first embodiment, the resin constituting the doctor blade 36 is selected in consideration of both wear resistance and productivity of the doctor blade 36 . Then, the developing frame 30 is configured so that the difference between the linear expansion coefficient α2 of the developing frame 30 and the linear expansion coefficient α1 of the doctor blade 36 (linear expansion coefficient difference α2−α1) satisfies the above-mentioned (Equation 1). resin was selected. Further, the cover frame 40 is configured so that the difference (linear expansion coefficient difference α2−α3) between the linear expansion coefficient α2 of the developing frame 30 and the linear expansion coefficient α3 of the cover frame 40 satisfies the above-mentioned (formula 2). We selected a resin that As a result, it is possible to suppress variations in the size of the SB gap G caused by temperature changes during the image forming operation (developing operation).

Further, in the first embodiment, the doctor blade 36 is fixed to the blade mounting portion 41 of the developing frame 30 over substantially the entire area corresponding to the maximum image area. As a result, the doctor blade 36 in the state fixed to the developing frame 30 is more stable than the case where only the two ends (two points) of the doctor blade 36 in the longitudinal direction of the doctor blade 36 are fixed to the blade mounting portion 41 . can increase the stiffness of As a result, it is possible to suppress the variation in the size of the SB gap G caused by the application of the agent pressure to the doctor blade 36 during the image forming operation (developing operation).

[Second embodiment]
In the above-described first embodiment, an example in which the adhesive A is applied to substantially the entire area of the blade mounting surface 41s of the developing frame 30 corresponding to the maximum image area has been described. By applying the adhesive A to the blade mounting surface 41s of the developing frame 30 over substantially the entire area corresponding to the maximum image area, the area corresponding to the maximum image area of the doctor blade 36 is bent. is fixed to the blade mounting surface 41s. As a result, of the area corresponding to the maximum image area of the doctor blade 36, the area bent to correct the straightness of the coating amount regulation surface 36r returns from the bent state to the original state before bending. It was a restraint to try.

On the other hand, in the second embodiment, the apparatus 100 does not apply the adhesive A over substantially the entire area of the blade mounting surface 41s of the developing frame 30 corresponding to the maximum image area, unlike the first embodiment. different from In the second embodiment, the device 100 stores in the memory the area corresponding to the maximum image area of the doctor blade 36, which is bent to correct the straightness of the coating amount regulation surface 36r. Subsequently, the apparatus 100 applies the adhesive A in the area corresponding to the maximum image area of the blade mounting surface 41s of the developing frame 30 based on the information on the area where the doctor blade 36 is bent, which is stored in the memory. A predetermined area is determined. Then, the device 100 applies the adhesive A to the determined predetermined region of the blade mounting surface 41s. The application width and film thickness of the adhesive A applied to the blade mounting surface 41s may be determined from the adhesive strength of the adhesive A and the application amount of the adhesive A in view of the man-hours and costs. As a result, the deflected area of the area corresponding to the maximum image area of the doctor blade 36 is fixed to the blade attachment surface 41s.

In addition, in order to suppress variation in the size of the SB gap G caused by the developer pressure being applied to the doctor blade 36 during the image forming operation (developing operation), the doctor blade fixed to the developing frame 30 It is required to increase the stiffness of 36. Therefore, in addition to the determined predetermined region of the blade mounting surface 41s, the apparatus 100 provides at least three locations including both ends and a substantially central portion of the region corresponding to the maximum image area of the blade mounting surface 41s of the developing frame 30. It is also desirable to apply the adhesive A further. Note that the substantially central portion of the area corresponding to the maximum image area of the blade mounting surface 41s is 10% or less of the length of the area in the longitudinal direction based on the center of the area corresponding to the maximum image area of the blade mounting surface 41s. It shall also cover the area translated to one end or the other by the length of .

As a result, in addition to the bent region of the region corresponding to the maximum image area of the doctor blade 36, at least three locations including both end portions and a substantially central portion of the region corresponding to the maximum image region of the doctor blade 36 are exposed to the blade. It will be fixed to the mounting surface 41s. Therefore, the rigidity of the doctor blade 36 fixed to the developing frame 30 can be further increased. can suppress variation in the magnitude of

It should be noted that the method of fixing at least three points including both ends and a substantially central portion 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 the adhesive A, but fixing with screws. may be FIG. 17 is a perspective view showing the configuration of the developing device 300 in which the doctor blade 36 is fixed to the blade mounting surface 41s by screws 80 at three locations, ie, both ends and a substantially central portion of the area corresponding to the maximum image area. be. FIG. 18 is a cross-sectional view of the developing device 300 taken along the cross-section H of FIG. In FIG. 17, the same reference numerals as in FIG. 2 denote the same configurations. In addition, in FIG. 18, the same reference numerals as in FIG. 15 indicate the same configuration.

In the example of FIG. 17, an insert nut is inserted into the fixing position of the blade mounting surface 41s of the developing device frame 30 . By fastening the screw 80 to the insert nut, the fastening force for fixing the doctor blade 36 to the blade mounting surface 41s is improved. If the fastening force can be maintained, the insert nut may be eliminated and a self-tapping screw may be used in which the screw 80 itself taps when the screw 80 is screwed in.

When fixing the doctor blade 36 to the blade mounting surface 41s with the screws 80, the doctor blade 36 should be fixed to the blade mounting surface 41s with the screws 80 after the adjustment of the SB gap G is completed in the positioning process described above. Just do it. In addition, the grasping portion 37 of the doctor blade 36 corresponds to the fixing width per one place by the screw 80 with respect to the screw fastening portion provided on the doctor blade 36 for fastening with the screw 80 to the blade mounting surface 41s. It is provided at a position shifted by a minute. In the example of FIG. 17, the fixed width per location by the screw 80 corresponds to the width of fastening the screw 80, and is approximately 5 mm.

(Other embodiments)
The present invention is not limited to the above embodiments, and various modifications (including organic combinations of each embodiment) are possible based on the gist of the present invention, and they are excluded from the scope of the present invention. is not.

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. Although an example having a configuration has been described, the present invention is not limited to this. As for the rigidity of the doctor blade 36 (single body), it is possible to bend the doctor blade 36 by the fingers 101, and if the developer flow and developer pressure during the development operation are within the range of design values, the developer guide portion 35 and doctor blade 36 may be integrally formed.

Further, in the above embodiment, as shown in FIG. 1, the image forming apparatus 60 configured to use the intermediate transfer belt 61 as an image carrier has been described as an example, but the present invention is not limited to this. It is also possible to apply the present invention to an image forming apparatus having a structure in which recording materials are brought into direct contact with the photosensitive drum 1 in order for transfer. In that case, the photosensitive drum 1 constitutes a rotatable image carrier that carries a toner image.

Further, in the above-described embodiment, as shown in FIG. 2, the developing device 3 is exemplified with a configuration in which the developing sleeve 70 rotates counterclockwise and the doctor blade 36 is arranged below the developing sleeve 70. However, it 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 arranged above the developing sleeve 70 .

Further, in the above-described embodiment, as shown in FIG. 2, the developing device 3 in which the developing chamber 31 and the stirring chamber 32 are arranged side by side with respect to the horizontal direction has been described as an example. can't The present invention can also be applied to the developing device 3 in which the developing chamber 31 and the stirring chamber 32 are arranged vertically in the direction of gravity.

Further, in the above embodiment, the developing device 3 is described as one unit, but the image forming section 600 (see FIG. 1) including the developing device 3 is integrated into a unit that can be attached to and detached from the image forming device 60 . A similar effect can be obtained even in the form of a process cartridge having a Further, as long as the image forming apparatus 60 includes the developing device 3 or the process cartridge, the present invention can be applied regardless of whether it is a monochrome machine or a color machine.

3 developing device 30 developing frame 36 doctor blade 41 blade mounting portion 70 developing sleeve

Claims (10)

A developer carrier that carries and conveys the developer to a development position; A method of manufacturing a developing device comprising: a regulating blade; and a resin developing frame having an attachment portion to which the regulating blade is attached and supporting the developer carrier, the method comprising:
The size of the gap between the developer carrier supported by the developing frame and the regulating blade attached to the mounting portion is set to be within a predetermined range along the longitudinal direction of the developer carrier. a positioning step of determining a position where the regulating blade is attached to the mounting portion while applying a force for bending the regulating blade to each of a plurality of locations in the longitudinal direction of the regulating blade;
The regulating blade is kept in a bent state by the force applied to the regulating blade so that the bonding operation between the regulating blade and the mounting portion is started after the positioning step is completed . an attaching step of attaching the regulating blade to the attaching portion using an adhesive;
A method of manufacturing a developing device, comprising: further comprising a measuring step of measuring the size of the gap;
In the positioning step, the force is applied to the plurality of locations in the longitudinal direction of the regulating blade so that the gap measured in the measuring step is within the predetermined range along the longitudinal direction of the developer carrier. Determine the position to attach the regulating blade to the mounting portion while applying to each
2. The method of manufacturing a developing device according to claim 1, wherein: The measuring step measures the size of the gap at each of a plurality of positions in the longitudinal direction of the developer carrier;
The positioning step satisfies that the tolerance of the size of the gap at each of the plurality of positions in the longitudinal direction of the developer carrier measured in the measuring step is 10% or less of a predetermined value. (2) determining the position at which the regulating blade is attached to the mounting portion while applying the force to each of the plurality of locations in the longitudinal direction of the regulating blade;
3. The method of manufacturing a developing device according to claim 2, wherein: 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 detects the gap. measuring the size of the gap by imaging the light emitted to the outside of the developing frame from
4. The method of manufacturing a developing device according to claim 2, wherein: The developer carrier is rotatable,
In the measuring step, the size of the gap is measured while the developer carrier is rotating.
5. The method of manufacturing a developing device according to claim 2, wherein: The plurality of locations in the longitudinal direction of the regulating blade include one end portion of the region of the regulating blade corresponding to the maximum image region, the other end portion of the region of the regulating blade corresponding to the maximum image region, and the maximum image region. and a central portion of the region of the regulating blade corresponding to the region
6. The method of manufacturing a developing device according to claim 1, wherein: The length of the region of the regulating blade corresponding to the maximum image region is a length corresponding to A3 size.
7. The method of manufacturing a developing device according to claim 6, wherein: further comprising an application step of applying the adhesive to the mounting portion;
8. The method according to any one of claims 1 to 7, wherein in the attaching step, the regulating blade is attached to the attaching portion using the adhesive applied to the attaching portion in the applying step. A method for manufacturing a developing device. further comprising an application step of applying the adhesive to the regulating blade;
8. The method according to any one of claims 1 to 7, wherein in the attaching step, the adhesive applied to the restricting blade in the applying step is used to attach the restricting blade to the attaching portion. A method for manufacturing a developing device. a first applying step of applying the adhesive to the mounting portion;
a second applying step of applying the adhesive to the regulating blade;
further having
In the attaching step, the regulating blade is attached to the attaching portion using the adhesive applied to the attaching portion in the first applying step and the adhesive applied to the regulating blade in the second applying step. 8. The manufacturing method of the developing device according to any one of claims 1 to 7, wherein the developing device is attached.

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