JP2019095602A - Development apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attach a resin regulating blade to a blade mounting portion of a resin developing frame and fix it with an adhesive, and when the regulating blade is attached to the blade mounting portion, the adhesive is inside the developing frame. Suppress invasion. SOLUTION: A developer carrier which is rotatably provided and which carries a developer containing a toner and a carrier for developing an electrostatic latent image formed on the image carrier, and a developer carrier so as to face the developer carrier. A resin-made developing blade that is arranged non-contact with the developer-supporting body and regulates the amount of the developing agent carried on the developing agent-supporting body, and a resin-made developing body having a mounting portion for mounting the regulating blade. The area of the regulatory blade corresponding to the maximum image area of the image area of the image carrier provided with the frame and capable of forming an image on the image carrier is fixed to the mounting portion by an adhesive, and the mounting portion is provided. A predetermined space for storing the adhesive is formed between the and the regulating blade. [Selection diagram] FIG. 13

Description

  The present invention relates to a developing device provided with a resin regulation blade.

  The developing device includes a developing frame, a rotatable developer carrier for carrying a developer for developing an electrostatic latent image formed on an image carrier, and a developer carried by the developer carrier. A control blade as a developer control member for controlling the amount is provided. The regulating blade is opposed to the developer carrier via a predetermined gap (hereinafter referred to as an SB gap) between the developer carrier and a direction parallel to the rotation axis of the developer carrier. Be placed. The SB gap is the shortest distance between the developer carrier and the regulating blade. By adjusting the size of the SB gap, the amount of the developer conveyed to the developing region where the developer carrier is opposed to the image carrier is adjusted.

  In recent years, there has been known a developing device provided with a resin-made developer regulating member molded of resin and a resin-made developing frame molded of resin (see Patent Document 1).

JP, 2014-197175, A

  In a developing device provided with a resin regulation blade and a resin development frame, a configuration is conceivable in which a resin regulation blade is attached to a blade attachment portion of a resin development frame and fixed with an adhesive. In such a configuration, an adhesive having a predetermined film thickness is applied to, for example, the surface (blade attachment surface) of the blade attachment portion to which the restriction blade is attached. When the restriction blade is attached to the blade attachment portion (during adhesion), a predetermined pressure is applied to the restriction blade, whereby the adhesive having a predetermined film thickness is crushed. At this time, the adhesive (excess adhesive) which has escaped to the outside of the surface to which the adhesive is applied may intrude into the inside of the developing device frame. When the extra adhesive adheres to the guide portion (developer guide portion) for guiding the developer to be conveyed toward the SB gap, in particular, in the developing frame, it is cured in the SB gap. There is a possibility that the flow of the developer conveyed toward the side may fluctuate. In such a case, the amount of the developer carried on the surface of the developer carrier may be uneven in the longitudinal direction of the developer carrier.

  The present invention has been made in view of the above problems. An object of the present invention is that in a configuration in which a resin regulation blade is attached to a blade attachment portion of a resin developing frame and fixed with an adhesive, the adhesive is a developing frame when the regulation blade is attached to the blade attachment portion An object of the present invention is to provide a developing device capable of suppressing intrusion into the inside of the image forming apparatus.

  In order to achieve the above object, a developing device according to an aspect of the present invention has the following configuration. That is, a developer carrier that is rotatably provided and carries a developer including a toner and a carrier for developing the electrostatic latent image formed on the image carrier, and is opposed to the developer carrier. A resin control blade disposed noncontact with the developer carrier and controlling the amount of developer carried on the developer carrier, and a resin having an attachment portion for attaching the regulation blade And the area of the regulating blade corresponding to the largest image area among the image areas of the image carrier capable of forming an image on the image carrier is fixed to the attachment portion by an adhesive. A predetermined space for storing the adhesive is formed between the attachment portion and the restriction blade.

  According to the present invention, in the configuration in which the resin regulation blade is attached to the blade attachment portion of the resin developing frame and fixed with an adhesive, the adhesive is the developing frame when the regulation blade is attached to the blade attachment portion. Intrusion into the interior of the

FIG. 1 is a cross-sectional view showing a configuration of an image forming apparatus. FIG. 2 is a perspective view showing the configuration of a developing device. FIG. 2 is a perspective view showing the configuration of a developing device. FIG. 2 is a cross-sectional view showing a configuration of a developing device. It is a perspective view showing composition of a doctor blade (single body) made of resin. It is a perspective view which shows the structure of the resin-made image development frame (single body). It is a schematic diagram for demonstrating the rigidity of the resin-made doctor blade (single-piece | unit). It is a schematic diagram for demonstrating the rigidity of the resin-made image development frame (single body). It is a schematic diagram for demonstrating the straightness of resin-made doctor blade (single-piece | unit). It is a perspective view for demonstrating the deformation | transformation of resin-made doctor blades resulting from a temperature change. It is sectional drawing for demonstrating the deformation | transformation of resin-made doctor blades resulting from agent pressure. FIG. 2 is a cross-sectional view showing the configuration of the developing device according to the first embodiment. FIG. 2 is a cross-sectional view (enlarged view) showing the configuration of the developing device according to the first embodiment. FIG. 6 is a cross-sectional view showing the configuration of a developing device according to a second embodiment. It is sectional drawing (enlarged view) which shows the structure of the image development apparatus which concerns on 2nd Embodiment. It is sectional drawing (enlarged view) which shows the structure of the image development apparatus which concerns on 3rd Embodiment. It is sectional drawing (enlarged view) which shows the structure of the image development apparatus which concerns on 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The following embodiments do not limit the present invention according to the claims, and all combinations of the features described in the first embodiment are essential to the solution means of the present invention. Not exclusively. The present invention can be implemented in various applications such as printers, various printing machines, copying machines, fax machines, multifunction machines and the like.

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 using the cross-sectional view of FIG. As shown in FIG. 1, the image forming apparatus 60 includes an endless intermediate transfer belt (ITB) 61 as an intermediate transfer member, and an upstream along the rotational direction of the intermediate transfer belt 61 (the direction of arrow C in FIG. 1). The four image forming units 600 are provided from the side to the downstream side. Each of the image forming units 600 forms toner images of respective colors of yellow (Y), magenta (M), cyan (C), and black (Bk).

  The image forming unit 600 includes a rotatable photosensitive drum 1 as an image carrier. Further, the image forming unit 600 includes a charging roller 2 as a charging unit, a developing device 3 as a developing unit, a primary transfer roller 4 as a primary transfer unit, and disposed along the rotation direction of the photosensitive drum 1. And a photoconductor cleaner 5 as photoconductor cleaning means.

  Each of the developing devices 3 is attachable to and detachable from the image forming apparatus 60. Each of the developing devices 3 has a developing container 50 for containing a two-component developer (hereinafter, simply referred to as a developer) containing nonmagnetic toner (hereinafter, simply referred to as toner) and a magnetic carrier. Further, each of the toner cartridges in which toners of respective colors of Y, M, C, and Bk are accommodated is removable from the image forming apparatus 60. The toners of the respective colors of Y, M, C, and Bk are supplied to the respective development containers 50 through toner transport paths. The details of the developing device 3 will be described later in FIGS. 2 to 4, and the details of the developing container 50 will be described later in FIG. 5.

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

  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.

  At a position facing the tension roller 6 via the intermediate transfer belt 61, an intermediate transfer member cleaner 8 as a belt cleaning unit is in contact. In addition, a secondary transfer outer roller 67 as a secondary transfer unit is disposed at a position facing the secondary transfer inner roller 66 via the intermediate transfer belt 61. The intermediate transfer belt 61 is nipped between the secondary transfer inner roller 66 and the secondary transfer outer roller 67. Thus, a secondary transfer nip portion as a secondary transfer portion is formed between the secondary transfer outer roller 67 and the intermediate transfer belt 61. In the secondary transfer nip portion, the toner image is adsorbed on the surface of the sheet S (for example, paper, film, etc.) by applying a predetermined pressure and a transfer bias (electrostatic load bias).

  The sheets S are stored in a state of being stacked in a sheet storage unit 62 (for example, a feeding cassette or a feeding deck). The feeding means 63 feeds the sheet S in accordance with the image formation timing by using, for example, a friction separation method using a feeding roller or the like. The sheet S fed out by the feeding means 63 is conveyed to a registration roller 65 disposed in the middle of the conveyance path 64. After the skew feed correction and timing correction are performed in the registration roller 65, the sheet S is conveyed to the secondary transfer nip portion. At the secondary transfer nip, the timing of the sheet S and that of the toner image coincide with each other, and secondary transfer is performed.

  A fixing device 9 is disposed downstream of the secondary transfer nip portion in the conveyance direction of the sheet S. A predetermined pressure and heat amount are applied from the fixing device 9 to the sheet S conveyed to the fixing device 9, whereby the toner image is melted and fixed on the surface of the sheet S. The sheet S on which the image is fixed in this manner is discharged to the discharge tray 601 as it is by the forward rotation of the discharge roller 69.

  When double-sided image formation is performed, the rear end of the sheet S is conveyed until the switching flapper 602 is passed by the forward rotation of the discharge roller 69, and then the discharge roller 69 is reversely rotated. As a result, the sheet S is conveyed to the duplex conveying path 603 with the front and rear ends replaced. Thereafter, at the next image forming timing, the sheet is conveyed again to the conveying path 64 by the re-feed roller 604.

(Image formation process)
At the time of image formation, the photosensitive drum 1 is rotationally driven by a motor. The charging roller 2 uniformly uniformly charges in advance the surface of the photosensitive drum 1 which is rotationally driven. 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 photosensitive 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 a developer. The developing device 3 develops the electrostatic latent image formed on the surface of the photosensitive drum 1 using a developer carried on the surface of the developing sleeve 70. As a result, toner adheres to the exposed portion on the surface of the photosensitive drum 1 and is visualized. 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. The toner slightly remaining on the surface of the photosensitive drum 1 after the primary transfer (transfer residual toner) is collected by the photosensitive cleaner 5 and is again prepared for the next imaging process.

  The image forming process of each color processed in parallel by the image forming unit 600 of each color of Y, M, C, and Bk is performed at the timing of sequentially overlapping on the upstream color toner image primarily transferred onto the intermediate transfer belt 61. To be 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. The toner (transfer residual toner) slightly remaining on the intermediate transfer belt 61 after the sheet S passes 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. The recording material S subjected to the fixing process by the fixing device 9 is discharged to the discharge tray 601.

  After the series of image forming processes as described above are completed, the process is prepared for the next image forming operation.

(Configuration of developing device)
The general configuration of the developing device will be described with reference to the perspective view of FIG. 2, the perspective view of FIG. 3, and the sectional view of FIG. FIG. 4 is a cross-sectional view of the developing device 3 at the cross section H of FIG.

  The developing device 3 is a resin developing frame (hereinafter simply referred to as a developing frame 30) molded of resin, and a resin cover formed separately from the developing frame 30 and molded of resin. The developing container 50 is formed of a frame (hereinafter simply referred to as a cover frame 40). 2 and 4 show the cover frame 40 attached to the developing frame 30, and FIG. 3 shows the cover frame 40 attached to the developing frame 30. It shows the absence state. The details of the configuration of the developing device frame 30 (single body) will be described later with reference to FIG.

  The developing container 50 is provided with an opening at a position corresponding to a developing area where the developing sleeve 70 faces the photosensitive drum 1. The developing sleeve 70 is rotatably disposed relative to the developing container 50 so that a part of the developing sleeve 70 is exposed at the opening of the developing container 50. At both end portions of the developing sleeve 70, bearings 71 which are bearing members are provided.

  The inside of the developing container 50 is partitioned (partitioned) into a developing chamber 31 as a first chamber and a stirring chamber 32 as a second chamber by a partition 38 extending in the vertical direction. The developing chamber 31 and the agitating 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 disposed side by side in the horizontal direction.

  Inside the developing sleeve 70, a magnet roll as a magnetic field generating means having a plurality of magnetic poles along the rotational direction of the developing sleeve 70 and generating a magnetic field for supporting the developer on the surface of the developing sleeve 70 is fixed. It is arranged. The developer in the developing chamber 31 is pumped up under the influence of the magnetic field of the magnetic pole 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 referred to as a supply chamber.

  In the developing chamber 31, a first conveying screw 33 as a conveying means for stirring and conveying the developer in the developing chamber 31 is disposed to face the developing sleeve 70. The first conveying screw 33 includes a rotating shaft 33a as a rotatable shaft and a spiral blade 33b as a developer conveying unit provided along the outer periphery of the rotating shaft 33a. Is rotatably supported. The bearing member is provided in each of the both ends of the rotating shaft 33a.

  Further, in the stirring chamber 32, a second conveying screw 34 as a conveying means for stirring the developer in the stirring chamber 32 and conveying the developer in the direction opposite to the first conveying screw 33 is disposed. The second conveying screw 34 includes a rotating shaft 34a as a rotatable shaft and a spiral blade 34b as a developer conveying unit provided along the outer periphery of the rotating shaft 34a. Is rotatably supported. The bearing member is provided in each of the both ends of the rotating shaft 34a. Then, the first conveyance screw 33 and the second conveyance screw 34 are rotationally driven to form a circulation path through which the developer circulates between the developing chamber 31 and the stirring chamber 32 via the communication portion 39. .

  In the developing container 50, a regulating blade (hereinafter referred to as a doctor blade 36) as a developer regulating member that regulates the amount of the developer carried on the surface of the developing sleeve 70 (also referred to as a developer coating amount) Non-contacting and attached to the surface of the sleeve 70. The doctor blade 36 has a coat amount regulating surface 36r as a regulating portion that regulates the amount of the developer carried on the surface of the developing sleeve 70. The doctor blade 36 is a resin doctor blade molded of resin. The configuration of the doctor blade 36 (single) will be described later with reference to FIG.

  The doctor blade 36 is disposed opposite to the developing sleeve 70 with a predetermined gap (hereinafter referred to as SB gap G) between the developing blade 70 and the developing sleeve 70 in a direction parallel to the rotation axis of the developing sleeve 70. Ru. In the present invention, the SB gap G is the shortest distance between the largest image area of the developing sleeve 70 and the largest image area of the doctor blade 36. The largest image area of the developing sleeve 70 refers to the area of the developing sleeve 70 corresponding to the largest image area of the image areas capable of forming an image on the surface of the photosensitive drum 1 in the rotational axis direction of the developing sleeve 70. It is The maximum image area of the doctor blade 36 refers to the doctor blade corresponding to the maximum image area of the image areas capable of forming an image on the surface of the photosensitive drum 1 in the direction parallel to the rotation axis of the developing sleeve 70. 36 areas. In the first embodiment, since the photosensitive drum 1 can form electrostatic latent images of a plurality of sizes, the largest image area is the largest image area of a plurality of sizes that can be formed on the photosensitive drum 1. An image area corresponding to a large size (for example, A3 size) is shown. On the other hand, in the modification in which the photosensitive drum 1 can form an electrostatic latent image of only one size, the largest image area is an image area of that size which can be formed on the photosensitive drum 1. It shall be read as showing something.

  The doctor blade 36 is disposed substantially opposite to the peak position of the magnetic flux density of the magnetic pole of the magnet roll. The developer supplied to the developing sleeve 70 is affected by the magnetic field of the magnetic pole of the magnet roll. Further, the developer regulated and scraped off by the doctor blade 36 tends to be stagnant in the upstream portion of the SB gap G. As a result, a developer reservoir is formed upstream of the doctor blade 36 in the rotational direction of the developing sleeve 70. Then, a part of the developer in the developer reservoir 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 36 r of the doctor blade 36. Thus, a thin layer of developer is formed on the surface of the developing sleeve 70.

  Then, 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 conveyed to the development area is adjusted. In the first embodiment, the size of the SB gap G is set to about 300 μm.

  The developer conveyed to the developing area forms a magnetic spike by earing in the developing area. When the magnetic brush contacts the photosensitive drum 1, the toner in the developer is supplied to the photosensitive drum 1. Then, the electrostatic latent image formed on the surface of the photosensitive drum 1 is developed as a toner image. The developer on the surface of the 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 step) is formed between the magnetic poles of the same polarity of the magnet roll. The surface of the developing sleeve 70 is peeled off by the repulsive magnetic field. The developer after the developing process peeled off from the surface of the developing sleeve 70 is collected into the developing chamber 31 by dropping 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 conveyed toward the SB gap G. The developer guide portion 35 and the developing frame 30 are integrally formed, and the developer guide portion 35 and the doctor blade 36 are separately formed. The developer guide portion 35 is formed inside the developing frame 30, and is disposed upstream of the coating amount regulating surface 36r of the doctor blade 36 in the rotational direction of the developing sleeve 70. By stabilizing the flow of the developer by the developer guide portion 35 and adjusting it to a predetermined developer density, the coating amount regulating surface 36r of the doctor blade 36 is in the position closest to the surface of the developing sleeve 70. The weight of the developer can be defined.

  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 covers a part of the opening of the developing frame 30 so that a part of the outer peripheral surface of the developing sleeve 70 is covered over the entire area in the longitudinal direction of the developing sleeve 70. At this time, the cover frame 40 covers a part of the opening of the developing frame 30 so that the developing area of the developing sleeve 70 facing the photosensitive drum 1 is exposed. Although the cover frame 40 is fixed to the developing frame 30 by ultrasonic bonding, the method of fixing the cover frame 40 to the developing frame 30 is any of screw fastening, snap fitting, adhesion, welding, etc. It may be a method.

(Structure of doctor blade made of resin)
The configuration of the doctor blade 36 (single body) will be described using the perspective view of FIG. 5.

  During the image forming operation (developing operation), the pressure of the developer (hereinafter referred to as the agent pressure) generated from the flow of the developer is applied to the doctor blade 36. The lower the rigidity of the doctor blade 36, the easier the doctor blade 36 is deformed when the agent pressure is applied to the doctor blade 36 during the image forming operation, and the size of the SB gap G tends to fluctuate. During the imaging operation, the agent pressure is applied in the short direction of the doctor blade 36 (the direction of the arrow M in FIG. 5). Therefore, in order to suppress the variation in the size of the SB gap G during the image forming operation, the rigidity in the short direction of the doctor blade 36 is increased to resist the deformation in the short direction of the doctor blade 36. It is desirable to do.

As shown in FIG. 5, the shape of the doctor blade 36 is plate-shaped from the viewpoint of mass productivity and cost. Further, as shown in FIG. 5, is to reduce the cross-sectional area of the side surface 36t of the doctor blade 36, further thickness direction of length t ₂ of the doctor blade 36, the lateral direction of the doctor blade 36 length t _It is smaller than ₁ . Thereby, the doctor blade 36 (single body) is configured to be easily deformed in the direction (arrow M direction in FIG. 5) orthogonal to the longitudinal direction (arrow N direction in FIG. 5) of the doctor blade 36. Therefore, in order to correct the straightness of the coat amount regulating surface 36r, the doctor blade 36 is a blade attachment portion 41 of the developing frame 30 in a state in which at least a part of the doctor blade 36 is bent in the arrow M direction in FIG. It is fixed to The details of the straightness correction of the doctor blade 36 will be described later with reference to FIG.

(Structure of developing frame made of resin)
The configuration of the developing device frame 30 (single body) will be described with reference to the perspective view of FIG. FIG. 6 shows a state in which the cover frame 40 is not attached to the developing frame 30.

  The developing device frame 30 has a developing chamber 31, and a stirring chamber 32 divided by the developing chamber 31 and the partition wall 38. The partition wall 38 may be formed of resin and may be formed separately from the developing device frame 30 or may be formed integrally with the developing device frame 30.

  The developing device frame 30 has a sleeve support portion 42 for rotatably supporting the developing sleeve 70 by supporting the bearings 71 provided at both ends of the developing sleeve 70. Further, the developing device frame 30 is integrally formed with the sleeve supporting portion 42 and has a blade attaching portion 41 for attaching the doctor blade 36. FIG. 6 shows a virtual state in which the doctor blade 36 is floated from the blade attachment portion 41.

  When 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 to fix the doctor blade 36 to the blade attachment portion 41. It is

(Stiffness of plastic doctor blade)
The rigidity of the doctor blade 36 (single body) will be described using the schematic view of FIG. 7. 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 attachment portion 41 of the developing device frame 30.

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

  For example, it is assumed 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 central portion 36z of the doctor blade 36 in the lateral direction 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.

(Stiffness of resin frame)
The rigidity of the developing device frame 30 (single body) will be described with reference to the schematic view of FIG. The rigidity of the developing device frame 30 (single body) is measured in a state where the doctor blade 36 is not fixed to the blade attaching portion 41 of the developing device frame 30.

  As shown in FIG. 8, a concentrated load F1 is applied in the lateral direction of the blade attachment portion 41 to the central portion 41z of the blade attachment portion 41 in the longitudinal direction of the blade attachment portion 41. At this time, the rigidity of the developing device frame 30 (single body) is measured based on the amount of deflection of the central portion 41z of the blade attachment portion 41 in the short direction of the blade attachment portion 41.

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

  It is assumed that concentrated loads F1 of the same size are applied to the central portion 36z of the doctor blade 36 and the central portion 41z of the blade attachment portion 41 of the developing device frame 30, respectively. The amount of bending of the central portion 36z of the doctor blade 36 at this time is ten or more times the amount of bending of the central portion 41z of the blade attachment portion 41. Therefore, the rigidity of the developing device frame 30 (single) is 10 times or more higher than the rigidity of the doctor blade 36 (single). Therefore, in a state where the doctor blade 36 is attached to the blade attachment portion 41 of the developing device frame 30 and the doctor blade 36 is fixed to the blade attaching portion 41 of the developing device frame 30, The rigidity of the body 30 becomes dominant. Further, when fixed to the developing frame 30 over the entire area of the maximum image area of the doctor blade 36, the developing frame 30 is compared with the case where only both end portions in the longitudinal direction of the doctor blade 36 are fixed. The rigidity of the doctor blade 36 in a fixed state is increased.

  Further, the magnitude of the rigidity of the developing frame 30 (single body) is larger than the magnitude of the rigidity of the cover frame 40 (single body). Therefore, in a state where 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 with respect to the rigidity of the cover frame 40 is Become dominant.

(Straightness correction of resin doctor blade)
The image is formed on the surface of the photosensitive drum 1 with respect to the direction parallel to the rotation axis of the developing sleeve 70 in response to the increase in the width of the sheet S, such as the width of the sheet S forming the image being A3 size. The length of the largest image area among the formable image areas is increased. Therefore, the length of the maximum image area of the doctor blade 36 increases as the width of the sheet S forming the image increases. When a doctor blade having a large length in the longitudinal direction is molded of resin, it is difficult to guarantee the straightness of the coating amount control surface of the resin doctor blade molded of resin. This is because, when a doctor blade having a large length in the longitudinal direction is molded with resin, when the thermally expanded resin is thermally shrunk, the location and delay of the thermal contraction progressing depending on the position in the longitudinal direction of the doctor blade It is because it is easy to produce a

  Therefore, in the resin doctor blade, as the length in the longitudinal direction of the doctor blade is increased, the SB gap is likely to be different in the longitudinal direction of the developer carrier due to the straightness of the coat amount regulating surface of the doctor blade. There is a tendency. If the SB gap is different in the longitudinal direction of the developer carrier, the amount of the developer carried on the surface of the developer carrier in the longitudinal direction of the developer carrier may be uneven.

  For example, a resin doctor blade (hereinafter referred to as a resin doctor blade compatible with A3 size) having a length in the longitudinal direction corresponding to A3 size was manufactured with the accuracy of a general resin molded product In this case, the straightness of the coat amount regulating surface is about 300 μm to 500 μm. In addition, even if a resin doctor blade compatible with A3 size is manufactured with high accuracy using a highly accurate resin material, the straightness of the coat amount regulating surface is about 100 μm to 200 μm.

  In the first embodiment, the size of the SB gap G is set to about 300 μm, and the tolerance of the SB gap G is set to ± 10% or less. Therefore, in the first embodiment, the adjustment value of the SB gap G is 300 μm ± 30 μm, which means that the tolerance of the SB gap G is up to 60 μm. For this reason, even if a resin doctor blade compatible with A3 size is manufactured with the accuracy of a general resin molded product or manufactured with a high accuracy resin material, the straightness of the coating amount regulation surface The degree accuracy only exceeds the allowable range of the SB gap G tolerance.

  In a developing device provided with a doctor blade made of resin, the SB gap G is made to fall within a predetermined range along the direction parallel to the rotation axis of the developer carrier regardless of the straightness of the coating amount regulating surface. Is desired. Therefore, in the first embodiment, even if a resin doctor blade having a low straightness of the coat amount regulating surface is used, the SB gap G rotates the developing sleeve 70 by correcting the straightness of the coat amount regulating surface. It is made to be within a predetermined range in a direction parallel to the axis.

  Here, the straightness of the coating amount regulating surface 36r of the doctor blade 36 will be described using the schematic view of FIG. The straightness of the coat amount regulating surface 36r is determined based on the maximum value and the minimum value of the outer shape of the coat amount regulating surface 36r based on a predetermined portion of the coat amount regulation surface 36r in the longitudinal direction of the coat amount regulating surface 36r. Expressed by the absolute value of the difference. For example, the central portion of the coating amount regulating surface 36r in the longitudinal direction of the coating amount regulating surface 36r is set as the origin of the orthogonal coordinate system, and a predetermined straight line passing through the origin is drawn at right angles to the X axis and the origin A straight line is taken as the Y axis. In this orthogonal coordinate system, the straightness of the coating amount regulating surface 36r 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 coating amount regulating surface 36r.

  As shown in FIG. 9, in the resin doctor blade (single body), the central portion of the coating amount regulating surface 36r of the doctor blade 36 is largely bent in the longitudinal direction of the doctor blade 36. Therefore, it is necessary to correct the straightness of the doctor blade 36r by reducing the difference in the positions of the tip portions 36e (36e1 to 36e5) of the doctor blade 36 shown in FIG. In view of the tolerance of the SB gap G, the mounting accuracy of the doctor blade 36 to the developing device frame 30, etc., it is necessary to correct the straightness of the coating amount regulating surface 36r of the doctor blade 36 to 50 μm or less. In view of the fact that the accuracy of straightness of the metal doctor blade is 20 μm or less by secondary cutting, more preferably, the straightness of the coating amount regulating surface 36r of the resin doctor blade 36 is 20 μm or less It is to correct. In consideration of a practical mass production process, the set value of straightness correction of the coat amount regulating surface 36r of the doctor blade 36 is set to about 20 μm to 50 μm.

  Therefore, a force (also called straightness correction force) for bending at least a part of the maximum image area of the doctor blade 36 is applied to the doctor blade 36, and at least a part of the maximum image area of the doctor blade 36 is bent. Thereby, the straightness of the coating amount regulation surface 36r of the doctor blade 36 is corrected to 50 μm or less.

  In the example of FIG. 9, with the external shapes of the tip portions 36e1 and 36e5 of the doctor blade 36 as a reference, the external shapes of the tip portions 36e2, 36e3 and 36e4 are matched with the reference, the tip portions 36e2, 36e3 and 36e4 The straightness correction force is applied in the direction of arrow I in FIG. As a result, 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, so the straightness of the coat amount regulation surface 36r of the doctor blade 36 is corrected to 50 μm or less can do. In the example of FIG. 9, the reference when the outer shape of the tip portion 36e of the doctor blade 36 is matched is the outer shape of the tip portions 36e1 and 36e5 (both ends in the longitudinal direction of the coating amount regulating surface 36r). It may be an outer shape of 36 e 3 (central portion in the longitudinal direction of the coat amount regulating surface 36 r). In that case, the straightness correction force is applied to the doctor blade 36 so that the outer shapes of the tip portions 36e1, 36e2, 36e4 and 36e5 are matched to the reference based on the outer shape of the tip portion 36e3 of the doctor blade 36 Do.

  As described above, in order to correct the straightness of the doctor blade 36, the doctor blade (individual unit so that at least a part of the maximum image area of the coating amount regulating surface 36r is bent when the straightness correction force is applied to the doctor blade 36). It is necessary to lower the rigidity of

(How to adjust the SB gap)
Adjustment of the SB gap G is performed by setting the doctor blade relative to the developing device frame 30 such that the relative position of the doctor blade 36 attached to the blade attachment portion 41 to the developing sleeve 70 supported by the sleeve support 42 is adjusted. It does by moving the position of 36. At a predetermined position of the blade attachment portion 41 determined by the adjustment of the SB gap G, the doctor blade 36 obtained by bending at least a part of the maximum image region of the doctor blade 36 is in advance all over the maximum image region of the blade attachment surface 41s. It is fixed by the adhesive A applied over. The maximum image area of the blade mounting surface 41s is the blade corresponding to the maximum image area of the image areas capable of forming an image on the surface of the photosensitive drum 1 in the direction parallel to the rotation axis of the developing sleeve 70. It is the area of the mounting surface 41s. At this time, in the maximum image area of the doctor blade 36, the area bent for correcting the straightness of the coat amount regulating surface 36r is fixed to the blade attachment portion 41. If the area which receives the force for bending at least a part of the maximum image area of the doctor blade 36 is fixed to the blade mounting portion 41 by the adhesive A, the adhesive on a part of the blade mounting surface 41s It is assumed that A does not have to be applied. Therefore, the adhesive A applied over the entire area of the largest image area of the blade attachment surface 41s means that the following conditions are satisfied. Of the area corresponding to the maximum image area of the doctor blade 36, the area bent for correcting the straightness of the coat amount regulating surface 36r, and the adhesive in the area of 95% or more of the maximum image area of the blade attachment surface 41s A is applied.

  As a result, an area of the maximum image area of the doctor blade 36 that is flexed to correct the straightness of the coating amount regulating surface 36r tries to return from the flexed state to the original state before flexing. It can be suppressed. By doing this, the doctor blade 36 is fixed to the blade attachment portion 41 in a state where the straightness of the coating amount regulating surface 36r is corrected to 50 μm or less.

  The size of the SB gap G is measured (calculated) by the method described below. In the measurement of the size of the SB gap G, the developing sleeve 70 is supported by the sleeve supporting portion 42 of the developing frame 30, the doctor blade 36 is attached to the blade attaching portion 41 of the developing frame 30, and the cover frame The process is performed in a state where 40 is fixed to the developing device frame 30.

  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. The light source inserted into the developing chamber 31 emits light from the inside of the developing chamber 31 toward the SB gap G. In each of five places corresponding to the front end portion 36e (36e1 to 36e5) of the doctor blade 36, a camera for capturing a light beam emitted from the SB gap G to the outside of the developing frame 30 is disposed.

  The cameras arranged at these five locations capture the light beam emitted from the SB gap G to the outside of the developing frame 30 in order to measure the positions of the tip portions 36 e (36 e 1 to 36 e 5) of the doctor blade 36. At this time, the camera reads the position at which the developing sleeve 70 most closely contacts the doctor blade 36 on the surface of the developing sleeve 70 and the tip portion 36 e (36 e 1 to 36 e 5) of the doctor blade 36. Subsequently, pixel values are converted into distances from image data read and generated by a camera, and the size of the SB gap G is calculated. If the calculated size of the SB gap G does not fall within the predetermined range, the SB gap G is adjusted. Then, when the calculated size of the SB gap G falls within a predetermined range, the doctor blade 36 obtained by bending at least a part of the maximum image area of the doctor blade 36 is fixed to the blade attachment portion 41 of the developing frame 30. Determined as a position.

  It is determined whether the SB gap G is in a predetermined range in a direction parallel to the rotation axis of the developing sleeve 70 by the method described below. First, 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, including both ends and the center of the maximum image area of the doctor blade 36) Measure G at 5 points or more. Then, the maximum value of the SB gap G, the minimum value of the SB gap G, and the median value of the SB gap G are extracted from the sample of the measured values of the SB gap G measured at five or more points.

  At this time, the absolute value of the difference between the maximum value of SB gap G and the median value of SB gap G is 10% or less of the median value of SB gap G, and the minimum value of SB gap G and the median value of SB gap G The absolute value of the difference may be 10% or less of the median value of the SB gap G. In this case, assuming that the tolerance of the SB gap G is ± 10% or less, it is satisfied that the SB gap G is within a predetermined range in the direction parallel to the rotation axis of the developing sleeve 70. For example, when the median value of the SB gap G is 300 μm from the sample of the measured values of the SB gap G measured at five or more points, 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 It is sufficient if it is the above. That is, in this case, the adjustment value of the SB gap G is 300 μm ± 30 μm, and the tolerance of the SB gap G is allowed up to 60 μm.

(Linear expansion coefficient)
Subsequently, the deformation of the doctor blade 36 and the developing device frame 30 caused by the temperature change due to the heat generated during the image forming operation will be described with reference to the perspective view of FIG. As heat generated during the developing operation, for example, 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 transport screw 33 and its bearing member rotate, And the heat generated when the developer passes through. The heat around the developing device 3 changes due to the heat generated during the image forming operation, and the temperatures of the doctor blade 36, the developing device frame 30, and the cover frame 40 also change.

  As shown in FIG. 10, the extension amount of the doctor blade 36 due to temperature change is H [μm], and the extension amount of the blade attachment surface 41s of the blade attachment portion 41 of the developing device frame 30 due to temperature change is I [μm]. Further, it is assumed that the linear expansion coefficient of the resin forming the doctor blade 36 and the linear expansion coefficient of the resin forming the developing device frame 30 are different. In this case, the amount of deformation of the developing frame 30 and the doctor blade 36 due to the temperature change is different due to the difference of the linear expansion coefficient, and the doctor blade 36 is used to fill the difference between H [μm] and I [μm]. It deforms in the direction of arrow J of 10. The deformation of the doctor blade 36 in the direction of the arrow J in FIG. 10 is hereinafter referred to as the deformation in the warp direction of the doctor blade 36. Then, the deformation in the warping direction of the doctor blade 36 leads to the fluctuation of the size of the SB gap G. In order to suppress the variation in the size of the SB gap G caused by heat, the linear expansion coefficient α2 of the resin constituting the sleeve supporting portion 42 and the blade attaching portion 41 of the developing frame 30 (single body) and the doctor blade 36 Each of the linear expansion coefficients α1 of the resin constituting (single) is related. That is, when the linear expansion coefficient α1 of the resin constituting the doctor blade 36 and the linear expansion coefficient α2 of the resin constituting the developing frame 30 are different, the deformation amount due to the temperature change is different due to the difference in the linear expansion coefficients. .

  In general, a resin material has a larger linear expansion coefficient than a metal material. When the doctor blade 36 is made of resin, the doctor blade 36 is warped and deformed along with the temperature change due to heat generated during the image forming operation, and the central portion in the longitudinal direction of the doctor blade 36 is easily bent. As a result, in the developing device in which the doctor blade 36 made of resin is fixed to the developing frame made of resin, the size of the SB gap G tends to fluctuate with the temperature change during the image forming operation.

  In order to correct the straightness of the coating amount control surface 36r to 50 μm or less, at least a part of the maximum image area of the doctor blade 36 is bent. Then, the doctor blade 36 in which at least a part of the largest image area of the doctor blade 36 is bent is attached to the entire area of the largest image area of the doctor blade 36 with respect to the blade attachment portion 41 of the developing frame 30. The method of fixing by is adopted.

  At this time, if there is a large difference between the coefficient of thermal expansion α2 of the resin constituting the developing frame 30 and the coefficient of thermal expansion α1 of the resin constituting the doctor blade 36, the following problems occur when a temperature change occurs. is there. That is, when a temperature change occurs, the deformation amount (stretching amount) of the doctor blade 36 due to the temperature change and the deformation amount (stretching amount) of the developing device frame 30 due to the temperature change are different. 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, the SB gap G is changed due to the temperature change during the image forming operation. It will change the size.

  Since the doctor blade 36 is fixed to the blade mounting surface 41s over the entire area of the maximum image area, it is necessary to suppress the variation of the size of the SB gap G due to the temperature change during the image forming operation. The fluctuation amount of the SB gap G caused by heat generally needs to be suppressed to ± 20 μm or less in order to suppress unevenness of the amount of developer carried on the surface of the developing sleeve 70 in the longitudinal direction of the developing sleeve 70.

  The difference in linear expansion coefficient α2 of the resin constituting the developing frame 30 having the sleeve supporting portion 42 and the blade attaching portion 41 with respect to the linear expansion coefficient α1 of the resin constituting the doctor blade 36 It is called α1. The change of the maximum deflection amount of the doctor blade 36 due to the linear expansion coefficient difference α2-α1 will be described using Table 1. The temperature change from normal temperature (23 ° C.) to high temperature (40 ° C.) with the doctor blade 36 fixed over the entire area of the maximum image area of the doctor blade 36 with respect to the blade attachment portion 41 of the developing frame 30 The maximum deflection of the doctor blade 36 was measured.

  The linear expansion coefficient of the resin constituting the developing frame 30 having the sleeve supporting portion 42 and the blade attaching portion 41 is α 1 [m / ° C.], and the linear expansion coefficient of the resin constituting the doctor blade 36 is α 2 [m / ° C.] Do. And the parameter of linear expansion coefficient difference (alpha) 2- (alpha) 1 was changed, and the result of having measured the largest deflection amount of the doctor blade 36, respectively is shown in Table 1. 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 “〇”, and the absolute value of the maximum amount of deflection of the doctor blade 36 is larger than 20 μm. The deflection amount is shown as "x".

As can be seen from Table 1, in order to suppress the fluctuation amount of the SB gap G due to 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 device frame 30 is configured so 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. A resin and a resin constituting the doctor blade 36 may be selected. When the resin constituting the developing device frame 30 and the resin constituting the doctor blade 36 are the same, the linear expansion coefficient difference α2−α1 becomes zero.

  When the adhesive A is applied to the doctor blade 36 and the developing device frame 30, the coefficient of linear expansion of the doctor blade 36 and the developing device frame 30 to which the adhesive A is applied will vary. However, the volume itself of the adhesive A applied to the doctor blade 36 and the developing frame 30 is very small, and can be ignored as the influence on the dimensional change of the adhesive A in the thickness direction due to the temperature change. Therefore, when the adhesive A is applied to the doctor blade 36 and the developing frame 30, the deformation in the warp direction of the doctor blade 36 due to the fluctuation of the linear expansion coefficient difference α2-α1 can be ignored. It is.

Similarly, since the cover frame 40 is fixed to the developing frame 30, if the amount of deformation of the developing frame 30 and the cover frame 40 due to temperature change is different, the deformation of the cover frame 40 in the warp direction is This leads to fluctuations in the size of the SB gap G. The linear expansion coefficient of the resin constituting the developing frame 30 having the sleeve supporting portion 42 and the blade attaching portion 41 is α 2 [m / ° C.], and the linear expansion coefficient of the resin constituting the cover frame 40 is α 3 [m / ° C.] I assume. Then, the difference between the linear expansion coefficient α3 of the resin constituting the cover frame 40 and the linear expansion coefficient α2 of the resin constituting the developing frame 30 having the sleeve supporting portion 42 and the blade attaching portion 41 will be referred to as the linear expansion coefficient hereinafter. Call the difference α3-α2. At this time, it is necessary to satisfy the following relational expression (Expression 2) in the same manner as in Table 1 for the linear expansion coefficient difference α3-α2.
(Formula 2)
−0.45 × 10 ⁻⁵ [m / ° C.] ≦ α3-α2 ≦ 0.55 × 10 ⁻⁵ [m / ° C.]

Therefore, the developing device frame 30 is configured such that the linear expansion coefficient difference α3-α2 is not less than −0.45 × 10 ⁻⁵ [m / ° C.] and not more than 0.55 × 10 ⁻⁵ [m / ° C.]. The resin and the resin constituting the cover frame 40 may be selected. When the resin forming the developing device frame 30 and the resin forming the cover frame 40 are selected to be the same, the linear expansion coefficient difference α3-α2 becomes zero.

(Agent pressure)
Subsequently, the deformation of the doctor blade 36 caused by the agent pressure generated from the flow of the developer being applied to the doctor blade 36 during the image forming operation will be described with reference to the sectional view of FIG. FIG. 11 is a cross-sectional view of the developing device 3 in a cross section orthogonal to the rotation axis of the developing sleeve 70 (cross section H in FIG. 2). FIG. 11 shows the configuration in the vicinity of the doctor blade 36 fixed by the adhesive A to the blade attachment portion 41 of the developing device frame 30.

  As shown in FIG. 11, a line connecting the closest contact position of the doctor blade 36 with the developing sleeve 70 on the coat amount regulating surface 36r and the rotation center of the developing sleeve 70 is taken as an X axis. At this time, the doctor blade 36 has a long length in the X-axis direction and high rigidity in the cross section in the X-axis direction. Further, as shown in FIG. 11, the ratio of the cross-sectional area T1 of the doctor blade 36 to the cross-sectional area T2 of the wall 30a of the developing frame 30 located in the vicinity of the developer guide 35 is smaller. .

  As described above, the rigidity of the developing device frame 30 (single) is 10 times or more higher than the rigidity of the doctor blade 36 (single). Therefore, in a state where the doctor blade 36 is fixed to the blade attachment portion 41 of the developing device frame 30, the rigidity of the developing device frame 30 with respect to the doctor blade 36 becomes dominant. As a result, during the image forming operation, the displacement amount (maximum deflection amount) of the coating amount regulating surface 36r of the doctor blade 36 when the doctor blade 36 receives the agent pressure is the displacement amount (maximum deflection amount) of the developing device frame 30 Substantially equivalent to

  During the image forming operation, the developer drawn up from the first conveying screw 33 is conveyed to the surface of the developing sleeve 70 through the developer guide portion 35. Thereafter, even when the thickness of the developer is defined to the size of the SB gap G by the doctor blade 36, the doctor blade 36 receives the agent pressure from various directions. As shown in FIG. 11, when the direction orthogonal to the X-axis direction (the direction defining the SB gap G) is the Y-axis direction, the agent pressure in the Y-axis direction is on the blade attachment surface 41 s of the developing frame 30. It is perpendicular to it. That is, the agent pressure in the Y-axis direction is a force in the direction in which the doctor blade 36 is pulled off from the blade attachment surface 41s. Therefore, the bonding force by the adhesive A needs to be sufficiently large with respect to the agent pressure in the Y-axis direction. Therefore, in view of the force to pull off the doctor blade 36 from the blade attachment surface 41s by the agent pressure and the adhesive force of the adhesive A, the adhesion area and application thickness of the adhesive A to the blade attachment surface 41s are optimum It is

(Configuration of Developing Device According to First Embodiment)
As described above, in response to the increase in the width of the sheet S forming the image, the length in the longitudinal direction of the maximum image area of the doctor blade 36 increases. When the doctor blade 36 having a large length in the longitudinal direction is molded by resin, it is difficult to guarantee the straightness of the coat amount regulating surface 36r of the doctor blade 36 made of resin. Therefore, in the first embodiment, at least a part of the maximum image area of the doctor blade 36 is bent in order to correct the straightness of the coating amount regulating surface 36r of the doctor blade 36 having a large length in the longitudinal direction to 50 μm or less. It is not. Then, a method is employed in which the doctor blade 36 in which at least a part of the maximum image area of the doctor blade 36 is bent is attached to the blade attachment portion 41 of the developing frame 30 and fixed by the adhesive A.

  As a result, an area of the maximum image area of the doctor blade 36 that is flexed to correct the straightness of the coating amount regulating surface 36r tries to return from the flexed state to the original state before flexing. It can be suppressed. For this reason, in order to prevent the deflection of the doctor blade 36 from being restored, it is possible to fix the doctor blade 36 to the blade attachment portion 41 with the adhesive A over substantially the entire image area of the doctor blade 36. desirable.

  In the first embodiment, in the configuration in which the doctor blade 36 made of resin is attached to the blade attachment portion 41 of the developing frame 30 made of resin and fixed by the adhesive A, the adhesive A having a predetermined film thickness is , And is applied to the blade mounting surface 41s of the blade mounting portion 41. Then, when the doctor blade 36 is attached to the blade attachment portion 41 (during adhesion), a predetermined pressure is applied to the doctor blade 36, whereby the adhesive A having a predetermined film thickness is crushed. At this time, there is a possibility that the adhesive (excess adhesive) which escapes to the outside of the surface (here, the blade attachment surface 41s) to which the adhesive A is applied may intrude into the inside of the developing frame 30. When the extra adhesive adheres to the developer guide portion 35 of the developing device frame 30 and is hardened, the flow of the developer conveyed toward the SB gap G may fluctuate. In such a case, the amount of developer carried on the surface of the developing sleeve 70 in the longitudinal direction of the developing sleeve 70 may be uneven.

  Therefore, in the first embodiment, in a configuration in which a resin doctor blade is attached to a blade attachment portion of a resin developing frame and fixed with an adhesive, the adhesive develops when the doctor blade is attached to the blade attachment portion. It is intended to suppress intrusion into the inside of the frame. Details will be described below.

  The configuration of the developing device according to the first embodiment will be described using the cross-sectional view of FIG. 12 and the cross-sectional view (enlarged view) of FIG. FIG. 12 is a cross-sectional view of the developing device 300 in a cross section orthogonal to the rotation axis of the developing sleeve 70. FIG. 13 is a cross-sectional view of the developing device 300 in a cross section orthogonal to the rotation axis of the developing sleeve 70, and shows the area I of FIG. 12 near the blade mounting portion 410 (especially the blade mounting surface 410s) of the developing device frame 310. ) Is an enlarged view of the developing device 300. In FIGS. 12 and 13, the same reference numerals as in FIG. 4 denote the same components. In the configuration of the developing device 300 according to the first embodiment, differences from the configuration of the developing device 3 described above with reference to FIG. 4 will be mainly described.

  As shown in FIGS. 12 and 13, the blade attachment portion 410 has a first blade support portion 420 and a second blade support portion 430 projecting from the developing device frame 310 and supporting the doctor blade 36 with an interval. It is provided. Also, the blade attachment surface 410s is a first blade support surface 420s of the first blade support 420 for supporting the doctor blade 36, and a second blade support surface 430s of the second blade support 430 for supporting the doctor blade 36. And is composed of. The shortest distance between the developing sleeve 70 and the second blade supporting surface 430s is longer than the shortest distance between the developing sleeve 70 and the first blade supporting surface 420s.

  In the first embodiment, the first blade support surface 420s is formed over substantially the entire image area of the blade attachment surface 410s. In the first embodiment, the second blade support surface 430s is formed over substantially the entire area of the maximum image area of the blade attachment surface 410s. Thereby, it is possible to stabilize the posture of the doctor blade 36 attached to the blade attachment portion 410 by being supported by the first blade support surface 420s and the second blade support surface 430s. If each of the first blade support surface 420s and the second blade support surface 430s is formed over an area of 90% or more of the maximum image area of the blade attachment surface 410s, the maximum image area of the blade attachment surface 410s It is considered to be formed over substantially the entire area of

  In the example of FIGS. 12 and 13, the groove 440 as a recess recessed by 0.2 [mm] or more from each of the first blade support surface 420 s and the second blade support surface 430 s corresponds to the first blade support 420 and the first blade support 420. It is formed between the two blade support portion 430. The groove 440 is a predetermined space for storing the adhesive (excess adhesive) which has escaped to the outside of the surface on which the adhesive A is applied when the doctor blade 36 is attached to the blade attachment portion 410 (during adhesion). Play a role as

  In the first embodiment, the groove 440 is formed over substantially the entire image area of the blade attachment surface 410s. If the groove 440 is formed over 90% or more of the maximum image area of the blade attachment surface 410s, it is considered to be formed over substantially the entire image area of the blade attachment surface 410s. . Further, in the first embodiment, the adhesive A is applied to the second blade support surface 430s which is the side far from the developing sleeve 70, and the first blade support which is the side closer to the developing sleeve 70. It is not applied to the surface 420s.

  In the first embodiment, for example, the length in the short direction of the second blade support surface 430s is 1.5 [mm], and the height of the adhesive A applied to the second blade support surface 430s is 800 [μm]. ]. In the first embodiment, for example, the distance between the first blade support 420 and the second blade support 430 (that is, the width of the groove 440) is 3.5 [mm]. In the first embodiment, for example, the amount of depression (that is, the depth of the groove 440) from the blade attachment surface 410s (each of the first blade support surface 420s and the second blade support surface 430s) is 0.4 [0.4]. mm]. In the first embodiment, for example, when the doctor blade 36 is attached to the blade attachment portion 410 (at the time of adhesion), the film thickness of the cured adhesive is a film thickness that can ensure sufficient adhesive strength. A predetermined pressure is applied to the doctor blade 36 until it reaches about 100 μm.

In such a first embodiment, the volume (volume) of the groove 440 is larger than the volume of the adhesive A applied to the second blade support surface 430s. Specifically, the total value of the area of the area where the adhesive A is applied to the blade attachment surface 410s (here, the second blade support surface 430s) is S ₁ [mm ² ], and the second blade support surface 430s is The film thickness of the adhesive A when the applied adhesive A cures is t [mm]. At this time, the volume of the adhesive A applied to the second blade support surface 430s is S ₁ × t [mm ³ ]. The length of the groove 440 in the longitudinal direction is L [mm], and the cross-sectional area of the groove 440 in a cross section orthogonal to the rotation axis of the developing sleeve 70 is S ₂ [mm ² ]. At this time, the volume (volume) of the groove 440 is S ₂ × L [mm ³ ]. Then, by satisfying the relationship of S ₂ × L [mm ³ ]> S ₁ × t [mm ³ ], the volume (volume) of the groove 440 is the volume of the adhesive A applied to the second blade support surface 430 s. Means greater than.

  By satisfying such a relationship, temporarily, all of the adhesive A having a predetermined film thickness applied to the blade attachment surface 410s (here, the second blade support surface 430s) is outside the second blade support surface 430s. Even if it escapes, all of the adhesive A is stored in the groove 440. Therefore, since the excess adhesive does not penetrate into the inside of the developing device frame 310, the excess adhesive adheres to the developer guide portion 35 and is cured to be conveyed toward the SB gap G, among others. There is no possibility that the flow of the developer will fluctuate.

  The adhesive A is applied to the second blade support surface 430s which is far from the developing sleeve 70 in order to prevent excess adhesive from invading the inside of the developing frame 310, but the developing sleeve 70 is used. It is desirable not to apply to the first blade support surface 420 s close in distance from. This is because, when the adhesive A is applied to the first blade support surface 420s, when the doctor blade 36 is attached to the blade attachment portion 410, a part of the adhesive that escapes to the outside of the first blade support surface 420s is This is because there is a possibility of invading the inside of the developing device frame 310. On the other hand, when the doctor blade 36 is attached to the blade attachment portion 410, all of the adhesive A having a predetermined film thickness applied to the second blade support surface 430s has escaped to the outside of the second blade support surface 430s. Also, all of the adhesive A is stored in the groove 440. Therefore, when the doctor blade 36 is attached to the blade attachment portion 410 (during adhesion), the adhesive that has escaped to the outside of the second blade support surface 430s is prevented from invading the inside of the developing frame 310. it can.

Second Embodiment
In the first embodiment described above, when the doctor blade is attached to the blade attachment portion, a predetermined space for accumulating the adhesive (excess adhesive) which has escaped to the outside of the surface to which the adhesive A is applied is provided. The groove part for forming was demonstrated in the example provided in the braid | blade attachment part side. On the other hand, in the second embodiment, when the doctor blade is attached to the blade attachment portion, a predetermined space for accumulating the adhesive (excess adhesive) which has escaped to the outside of the surface to which the adhesive A is applied The example in which the groove part for forming is provided in the doctor blade side is explained.

  The configuration of the developing device according to the second embodiment will be described using the cross-sectional view of FIG. 14 and the cross-sectional view (enlarged view) of FIG. FIG. 14 is a cross-sectional view of the developing device 301 in a cross section orthogonal to the rotation axis of the developing sleeve 70. FIG. 15 is a cross-sectional view of the developing device 301 in a cross section orthogonal to the rotation axis of the developing sleeve 70, and is an enlarged view of the developing device 301 in the vicinity of the blade mounting portion 41 (especially the blade mounting surface 41s) of the developing device frame 30. FIG. In FIG. 14 and FIG. 15, ones given the same reference numerals as in FIG. 4, FIG. 12, and FIG. The configuration of the developing device 301 according to the second embodiment will be described focusing on differences from the configuration of the developing device 300 described above with reference to FIGS. 12 and 13.

  In doctor blade 360, a first blade contact portion 370 and a second blade contact portion 380, which are portions where doctor blade 360 contacts blade attachment portion 41 when doctor blade 360 is attached to blade attachment portion 41, are spaced apart. Is provided. The shortest distance between the developing sleeve 70 and the second blade contact portion 380 is longer than the shortest distance between the developing sleeve 70 and the first blade contact portion 370.

  As shown in FIGS. 14 and 15, the groove portion 390 as a recessed portion recessed by 0.2 [mm] or more from each of the first blade contact surface 370s and the second blade contact surface 380s corresponds to the first blade contact portion 370. It is formed between the second blade contact portion 380. The first blade contact surface 370s refers to the surface of the first blade contact portion 370 that contacts the blade attachment portion 41, and the second blade contact surface 380s corresponds to the blade attachment portion 41 of the second blade contact portion 380. It is the surface that contacts. The groove portion 390 is a predetermined space for storing the adhesive (excess adhesive) which has escaped to the outside of the surface to which the adhesive A is applied when the doctor blade 360 is attached to the blade attachment portion 41 (during adhesion). Play a role as

  In the second embodiment, the groove 390 is formed over substantially the entire area of the maximum image area of the doctor blade 360. If the groove 390 is formed over an area of 90% or more of the maximum image area of the doctor blade 360, it is considered to be formed over substantially the entire area of the maximum image area of the doctor blade 360. Further, in the second embodiment, the adhesive A is applied to the second blade contact surface 380s on the side far from the developing sleeve 70, and the first blade contact on the side closer from the developing sleeve 70. It is not applied to the surface 370s.

  In such a second embodiment, the volume (volume) of the groove 390 is larger than the volume of the adhesive A applied to the second blade contact surface 380 s. By satisfying such a relationship, temporarily, all of the adhesive A having a predetermined film thickness applied to the doctor blade 360 (here, the second blade contact surface 380s) goes to the outside of the second blade contact surface 380s. Even if it escapes, all of the adhesive A is stored in the groove 390. Therefore, since the excess adhesive does not penetrate into the inside of the developing device frame 30, the excess adhesive adheres to the developer guide portion 35 and is cured, for example, so as to be conveyed toward the SB gap G. There is no possibility that the flow of the developer will fluctuate.

  In order to prevent excess adhesive from entering the inside of the developing device frame 30, the adhesive A is applied to the second blade contact surface 380s which is far from the developing sleeve 70, but the developing sleeve It is desirable not to apply to the first blade contact surface 370s close in distance from 70. This is because, when the adhesive A is applied to the first blade contact surface 370s, when the doctor blade 360 is attached to the blade attachment portion 41, a part of the adhesive that has escaped to the outside of the first blade contact surface 370s This is because there is a possibility of invading the inside of the developing device frame 30. On the other hand, when the doctor blade 360 is attached to the blade attachment portion 41, all of the adhesive A having a predetermined film thickness applied to the second blade contact surface 380s escapes to the outside of the second blade contact surface 380s. Also, all of the adhesive A is stored in the groove 390. Therefore, when the doctor blade 360 is attached to the blade attachment portion 41 (during adhesion), the adhesive that has escaped to the outside of the second blade contact surface 380s is prevented from invading the inside of the developing frame 30. it can.

Third Embodiment
In the third embodiment, when the doctor blade is attached to the blade attachment portion, the groove for forming a predetermined space for storing the escaped adhesive on the outside of the surface to which the adhesive A is applied is the blade. An example provided on both the attachment portion side and the doctor blade side will be described.

  The configuration of the developing device according to the third embodiment will be described using the cross-sectional view (enlarged view) of FIG. FIG. 16 is a cross-sectional view of the developing device 302 in a cross section orthogonal to the rotation axis of the developing sleeve 70, and is an enlarged view of the developing device 302 in the vicinity of the blade mounting portion 410 (especially the blade mounting surface 410s) of the developing device frame 310. FIG. In FIG. 16, ones given the same reference numerals as in FIGS. 13 and 15 indicate the same configurations. In the configuration of the developing device 302 according to the third embodiment, differences from the configuration of the developing device 300 described above with reference to FIG. 13 and the configuration of the developing device 301 described above with reference to FIG.

  In the third embodiment, as shown in FIG. 16, the groove 440 as a recess recessed 0.2 mm or more from each of the first blade support surface 420 s and the second blade support surface 430 s is a first blade. It is formed between the support 420 and the second blade support 430. Further, in the third embodiment, as shown in FIG. 16, the groove portion 390 as a recessed portion recessed by 0.2 mm or more from each of the first blade contact surface 370s and the second blade contact surface 380s is the first. The first blade contact portion 370 and the second blade contact portion 380 are formed.

  Then, when the groove portion 440 and the groove portion 390 respectively attach the doctor blade 360 to the blade attachment portion 410 (at the time of adhesion), the adhesive (extra adhesive) which escapes to the outside of the surface to which the adhesive A is applied. Serves as a predetermined space for storing

  In the third embodiment, the groove 440 of the blade attachment portion 410 is formed over substantially the entire area of the maximum image area of the blade attachment surface 410s, and the groove 390 of the doctor blade 360 is the maximum of the doctor blade 360. It is formed over substantially the entire area of the image area. Also, the adhesive A is applied to the second blade support surface 430s and the second blade contact surface 380s which are far from the developing sleeve 70, and the first blade support is closer to the developing sleeve 70. It is not applied to the surface 420s or the first blade contact surface 370s.

  In the third embodiment, the total volume (volume) of the groove portion 440 of the blade attachment portion 410 and the groove portion 390 of the doctor blade 360 is applied to the second blade support surface 430s and the second blade contact surface 380s. It is larger than the volume of the adhesive A. By satisfying such a relationship, temporarily, all of the adhesive A applied to the second blade support surface 430s and the second blade contact surface 380s go to the outside of the second blade support surface 430s and the second blade contact surface 380s. Even if it escapes, all of the adhesive A is stored in the groove 440 and the groove 390. Therefore, since the excess adhesive does not penetrate into the inside of the developing device frame 310, the excess adhesive adheres to the developer guide portion 35 and is cured to be conveyed toward the SB gap G, among others. There is no possibility that the flow of the developer will fluctuate.

Fourth Embodiment
In the first to third embodiments, when the doctor blade is attached to the blade attachment portion, the groove for forming a predetermined space for storing the adhesive that has escaped to the outside of the adhesive application surface is the blade attachment. The example provided in either or both of the part and the doctor blade has been described.

  On the other hand, in the fourth embodiment, a groove for forming a predetermined space for storing an excess adhesive is not provided in advance in any of the blade attachment portion and the doctor blade. Instead, in the fourth embodiment, when the doctor blade is attached to the blade attachment portion, a predetermined adhesive agent (excess adhesive) is stored on the outside of the surface on which the adhesive A is applied. An example in which a space is formed for the first time will be described.

  The configuration of the developing device according to the fourth embodiment will be described using the cross-sectional view (enlarged view) of FIG. FIG. 17 is a cross-sectional view of the developing device 303 in a cross section orthogonal to the rotation axis of the developing sleeve 70, and is an enlarged view of the developing device 302 in the vicinity of the blade mounting portion 4100 (particularly, blade mounting surface 4100s) of the developing device frame 3100. FIG. In FIG. 17, components to which the same reference numerals as in FIGS. 13, 15, and 16 denote the same components. The configuration of the developing device 303 according to the fourth embodiment is different from the configuration of the developing device 300 described above in FIG. 13, the configuration of the developing device 301 described above in FIG. 15, or the configuration of the developing device 302 described above in FIG. The explanation will be focused on the place.

  As shown in FIG. 17, by attaching the doctor blade 3600 to the blade attachment portion 4100, a predetermined space (3900) for storing the escaped adhesive on the outside of the application surface of the adhesive and the blade attachment portion 4100 It is formed for the first time with the doctor blade 3600. In such a fourth embodiment, the volume (volume) of the predetermined space (3900) for storing the excess adhesive is higher than the volume of the adhesive A applied to the blade attachment portion 4100 or the doctor blade 3600. It is getting bigger. By satisfying such a relationship, even if all of the adhesive A applied to the blade attachment portion 4100 or the doctor blade 3600 escapes to the outside of the surface to which the adhesive A is applied, the adhesive A All is stored in a predetermined space (3900) for storing excess adhesive. Therefore, the excess adhesive does not intrude into the inside of the developing device frame 3100, so that the excess adhesive adheres to the developer guide portion 35 and is cured, for example, toward the SB gap G. There is no possibility that the flow of the developer will fluctuate.

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

  In the above embodiment, as shown in FIG. 1, the image forming apparatus 60 configured to use the intermediate transfer belt 61 as an intermediate transfer member 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 configuration in which the recording material is sequentially brought into contact with the photosensitive drum 1 for transfer.

  Further, in the above embodiment, the developing device 300 has been described as one unit, but a process in which the image forming unit 600 (see FIG. 1) including the developing device 300 is integrally united and made removable from the image forming device 60 Similar effects can be obtained even in the form of a cartridge. Further, as long as the image forming apparatus 60 provided with the developing device 300 or the process cartridge, the present invention can be applied regardless of a monochrome machine or a color machine.

36 doctor blade 70 developing sleeve 300 developing device 310 developing frame 410 blade mounting portion 440 groove portion

Claims (6)

A developer carrier which is rotatably provided and carries a developer including a toner and a carrier for developing the electrostatic latent image formed on the image carrier, and the development so as to face the developer carrier Developing agent made of resin having a resin control blade disposed in non-contact with the developer carrier and controlling the amount of developer carried on the developer carrier, and a mounting portion for mounting the control blade Equipped with a frame,
An area of the restriction blade corresponding to the largest image area of the image area of the image carrier capable of forming an image on the image carrier is fixed to the attachment portion by an adhesive.
A developing device is characterized in that a predetermined space for storing the adhesive is formed between the mounting portion and the regulating blade. The mounting portion is provided with a first support portion and a second support portion which project from the developing frame and support the regulating blade, with an interval therebetween.
The restriction blade is configured such that a region of the restriction blade corresponding to the largest image area of the image carrier supports a first support surface of the first support portion for supporting the restriction blade and the restriction blade of the second support portion. It is supported by the supporting second support surface and fixed to the mounting portion by an adhesive.
In the mounting portion, a recessed portion recessed by 0.2 mm or more from each of the first support surface and the second support surface is formed between the first support portion and the second support portion.
The developing device according to claim 1, wherein the predetermined space is formed between the recess portion of the mounting portion and the restriction blade. Each of the first support surface and the second support surface is formed over substantially the entire area of the mounting portion corresponding to the maximum image area of the image carrier.
The recess is formed over substantially the entire area of the mounting portion corresponding to the largest image area of the image carrier.
The predetermined space is formed between the recess of the mounting portion and the restriction blade over substantially the entire area of the mounting portion corresponding to the maximum image area of the image carrier. The developing device according to claim 2, characterized in that: The shortest distance between the developer carrier and the second support surface is longer than the shortest distance between the developer carrier and the first support surface,
The area of the restriction blade corresponding to the largest image area of the image carrier is fixed to the second support by the adhesive and not fixed to the first support. Or the developing device according to 3. The restriction blade is arranged such that the gap between the developer carrier and the restriction blade is within a predetermined range over substantially the entire area of the restriction blade corresponding to the maximum image area of the image carrier. The developing device according to any one of claims 1 to 4, wherein the developing device is fixed to the mounting portion by an adhesive in a bent state. In the predetermined range, the absolute value of the difference between the maximum value of the gap and the median value of the gap is 10% or less of the median value of the gap, and the difference between the minimum value of the gap and the median value of the gap The developing device according to claim 5, wherein the absolute value of is a range that satisfies 10% or less of the central value of the gap.

Images