JP7009178B2 - Developer - Google Patents

Description

The present invention relates to a developing device including a resin regulating blade.

The developing apparatus includes a developing frame, a rotatable developer carrier that supports a developer for developing an electrostatic latent image formed on the image carrier, and a developer that is supported on the developer carrier. It is equipped with a regulating blade as a developer regulating member that regulates the amount. The regulating blade faces the developer carrier through a predetermined gap (hereinafter referred to as SB gap) with the developer carrier in 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 regulatory blade. By adjusting the size of the SB gap, the amount of the developer transported to the developing region where the developer carrier faces the image carrier is adjusted.

In recent years, a developing device including a resin-made developer regulating member molded from a resin and a resin-made developing frame formed from a resin has been known (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-197175

In a developing apparatus provided with a resin-made regulating blade and a resin-made developing frame, a configuration in which a resin-made regulating blade is attached to a blade mounting portion of the resin-made developing frame and fixed by an adhesive can be considered. In such a configuration, an adhesive having a predetermined film thickness is applied to, for example, the surface (blade mounting surface) of the blade mounting portion on which the regulation blade is mounted. Then, when the regulation blade is attached to the blade attachment portion (during bonding), a predetermined pressure is applied to the regulation blade, so that the adhesive having a predetermined film thickness is crushed. At this time, the adhesive (excessive adhesive) that has escaped to the outside of the surface to which the adhesive has been applied may invade the inside of the developing frame. When this extra adhesive adheres to the guide portion (developer guide portion) for guiding the developer to be conveyed toward the SB gap of the developing frame, and is cured, the SB gap is formed. There is a risk that the flow of the developer transported toward it will fluctuate. In such a case, the amount of the developer supported 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 to attach a resin regulating blade to a resin developing frame and bond it with an adhesive . When the regulating blade is attached to the developing frame , the adhesive is applied to the inside of the developing frame. It is an object of the present invention to provide a developing apparatus capable of suppressing intrusion.

In order to achieve the above object, the developing apparatus according to one aspect of the present invention has the following configuration. That is, the developer carrier rotatably provided and carrying the developer containing the toner and the carrier for developing the electrostatic latent image formed on the image carrier and the developer carrier are not in contact with each other. A resin-made regulating blade that is arranged so as to face each other and regulates the amount of the developer carried on the developer-supporting body, and a resin-made developing frame having a mounting portion for mounting the regulating blade . The mounting portion is provided with a first support portion that protrudes from the developing frame and has a first support surface for supporting the restricting blade, and a portion that protrudes from the developing frame and supports the restricting blade. Each of the second support portions having the second support surface of the above is provided with an interval, and the shortest distance between the developer carrier and the second support surface is the developer carrier and the second support surface. With the restricting blade being supported by the first support surface and supported by the second support surface, which is longer than the shortest distance from one support surface, the restricting blade is imaged on the image carrier. The region corresponding to the maximum image region in which the A recessed portion of 0.2 [mm] or more from each of the support surface and the second support surface is formed between the first support portion and the second support portion, and the recessed portion and the regulation blade are formed. It is characterized in that a predetermined space for accumulating the adhesive is formed between the and.

According to the present invention, in a configuration in which a resin regulating blade is attached to a resin developing frame and bonded with an adhesive , when the regulating blade is attached to the developing frame , the adhesive is inside the developing frame. It is possible to suppress invasion.

It is sectional drawing which shows the structure of an image forming apparatus. It is a perspective view which shows the structure of a developing apparatus. It is a perspective view which shows the structure of a developing apparatus. It is sectional drawing which shows the structure of a developing apparatus. It is a perspective view which shows the structure of the doctor blade (single substance) made of resin. It is a perspective view which shows the structure of the development frame (single substance) made of resin. It is a schematic diagram for demonstrating the rigidity of the doctor blade (single substance) made of resin. It is a schematic diagram for demonstrating the rigidity of the development frame (single substance) made of resin. It is a schematic diagram for demonstrating the straightness of the doctor blade (single substance) made of resin. It is a perspective view for demonstrating the deformation of a resin doctor blade due to a temperature change. It is sectional drawing for demonstrating the deformation of the doctor blade made of resin due to the agent pressure. It is sectional drawing which shows the structure of the developing apparatus which concerns on 1st Embodiment. It is sectional drawing (enlarged view) which shows the structure of the developing apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the developing apparatus which concerns on 2nd Embodiment. It is sectional drawing (enlarged view) which shows the structure of the developing apparatus which concerns on 2nd Embodiment. It is sectional drawing (enlarged view) which shows the structure of the developing apparatus which concerns on 3rd Embodiment. It is sectional drawing (enlarged view) which shows the structure of the developing apparatus which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the present invention according to the scope of claims, and that all combinations of features described in the first embodiment are essential for the means for solving the present invention. Not exclusively. The present invention can be implemented in various applications such as printers, various printing machines, copiers, fax machines, and multifunction devices.

[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, the image forming apparatus 60 is upstream along the rotation direction (arrow C direction in FIG. 1) of the endless intermediate transfer belt (ITB) 61 as an intermediate transfer body and the intermediate transfer belt 61. Four image forming portions 600 are provided from the side to the downstream side. Each of the image forming portions 600 forms a toner image of each color of yellow (Y), magenta (M), cyan (C), and black (Bk).

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

Each of the developing devices 3 is removable from the image forming device 60. Each of the developing devices 3 has a developing container 50 that houses a non-magnetic toner (hereinafter, simply referred to as toner) and a two-component developer containing a magnetic carrier (hereinafter, simply referred to as a developing agent). Further, each of the toner cartridges containing the toners of each color of Y, M, C, and Bk can be attached to and detached from the image forming apparatus 60. The toners of each color of Y, M, C, and Bk are supplied to each of the developing containers 50 via the toner transport path. The details of the developing apparatus 3 will be described later in FIGS. 2 to 4, and the details of the developing container 50 will be described later in 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 conveyed and driven in the direction of arrow C in FIG. The secondary transfer inner roller 66 also serves as a drive roller for driving the intermediate transfer belt 61. With the rotation of the secondary transfer inner roller 66, 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 surface side of the intermediate transfer belt 61. Further, by bringing the intermediate transfer belt 61 into contact with the photoconductor drum 1, a primary transfer nip portion as a primary transfer portion is formed between the photoconductor drum 1 and the intermediate transfer belt 61.

An intermediate transfer body cleaner 8 as a belt cleaning means is in contact with the position facing 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 via the intermediate transfer belt 61. The intermediate transfer belt 61 is sandwiched between the secondary transfer inner roller 66 and the secondary transfer outer roller 67. As a result, a secondary transfer nip portion as a secondary transfer portion is formed between the secondary transfer outer roller 67 and the intermediate transfer belt 61. In the secondary transfer nip portion, the toner image is adsorbed on the surface of the sheet S (for example, paper, film, etc.) by applying a predetermined pressing force and transfer bias (electrostatic load bias).

The seat S is stored in a state of being loaded on the seat storage unit 62 (for example, a feeding cassette, a feeding deck, or the like). The feeding means 63 feeds the sheet S at the timing of image formation 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 resist roller 65 arranged in the middle of the conveying path 64. After performing skew correction and timing correction in the resist roller 65, the sheet S is conveyed to the secondary transfer nip portion. At the secondary transfer nip portion, the timings of the sheet S and the toner image match, and the secondary transfer is performed.

A fixing device 9 is arranged on the downstream side of the sheet S in the transport direction from the secondary transfer nip portion. When a predetermined pressure and heat amount are applied to the sheet S conveyed to the fixing device 9 from the fixing device 9, 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 way is discharged to the discharge tray 601 as it is by the forward rotation of the discharge roller 69.

When forming a double-sided image, the discharge roller 69 is rotated in the reverse direction after being conveyed until the rear end of the sheet S passes through the switching flapper 602 by the forward rotation of the discharge roller 69. As a result, the front and rear ends of the sheet S are exchanged, and the sheet S is transported to the double-sided transport path 603. Then, at the next image formation timing, the image is conveyed to the transfer path 64 again by the refeed roller 604.

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

The developing device 3 has a rotatable developing sleeve 70 as a developing agent carrier that supports the developing agent. The developing apparatus 3 develops an electrostatic latent image formed on the surface of the photoconductor drum 1 by using a developing agent supported on the surface of the developing sleeve 70. As a result, the toner adheres to the exposed portion on the surface of the photoconductor 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 photoconductor drum 1 is transferred onto the intermediate transfer belt 61. A small amount of toner (transfer residual toner) remaining on the surface of the photoconductor drum 1 after the primary transfer is recovered by the photoconductor cleaner 5 and is prepared for the next image formation process again.

The image formation process of each color processed in parallel by the image forming unit 600 of each color of Y, M, C, and Bk is at the timing of sequentially superimposing on the toner image of the upstream color primaryly transferred on the intermediate transfer belt 61. Will 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. A small amount of toner (transfer residual toner) remaining on the intermediate transfer belt 61 after the sheet S has passed through the secondary transfer nip portion is recovered by the intermediate transfer cleaner 8. The fixing device 9 fixes the toner image transferred on the sheet S. The recording material S that has undergone the fixing process by the fixing device 9 is discharged to the discharge tray 601.

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)
A general configuration of the developing apparatus 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 apparatus 3 in the cross section H of FIG.

The developing apparatus 3 is formed separately from the developing frame body 30 made of resin molded by resin (hereinafter, simply referred to as developing frame body 30) and the developing frame body 30, and is made of resin and molded by resin. A developing container 50 composed of a frame body (hereinafter, simply referred to as a cover frame body 40) is provided. 2 and 4 show a state in which the cover frame body 40 is attached to the developing frame body 30, and FIG. 3 shows a state in which the cover frame body 40 is attached to the developing frame body 30. It shows no state. The details of the configuration of the developing frame 30 (single substance) will be described later with reference to FIG.

The developing container 50 is provided with an opening at a position corresponding to the developing region where the developing sleeve 70 faces the photoconductor 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 in the opening of the developing container 50. Bearings 71, which are bearing members, are provided at both ends of the developing sleeve 70.

The inside of the developing container 50 is divided (partitioned) into a developing chamber 31 as a first chamber and a stirring chamber 32 as a second chamber by a partition wall 38 extending in the vertical direction. The developing chamber 31 and the stirring chamber 32 are connected at both ends in the longitudinal direction via two communication portions 39 of the partition wall 38. Therefore, the developer can be communicated between the developing chamber 31 and the stirring chamber 32 via 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, a magnet roll having a plurality of magnetic poles along the rotation direction of the developing sleeve 70 and as a magnetic field generating means for generating a magnetic field for supporting the developer on the surface of the developing sleeve 70 is fixed. And are arranged. The developer in the developing chamber 31 is pumped up by the influence of the magnetic field due to the magnetic poles of the magnet roll and supplied to the developing sleeve 70. Since the developing agent is supplied from the developing chamber 31 to the developing sleeve 70 in this way, the developing chamber 31 is also referred to as a supply chamber.

In the developing chamber 31, a first transport screw 33 as a transporting means for stirring and transporting the developer in the developing chamber 31 is arranged facing the developing sleeve 70. The first transport screw 33 includes a rotary shaft 33a as a rotatable shaft portion and a spiral blade portion 33b as a developer transport portion provided along the outer periphery of the rotary shaft 33a, with respect to the developing container 50. It is rotatably supported. Bearing members are provided at both ends of the rotating shaft 33a.

Further, in the stirring chamber 32, a second transport screw 34 is arranged as a transport means for stirring the developer in the stirring chamber 32 and transporting the developer in the direction opposite to that of the first transport screw 33. The second transport screw 34 includes a rotary shaft 34a as a rotatable shaft portion and a spiral blade portion 34b as a developer transport portion provided along the outer periphery of the rotary shaft 34a, with respect to the developing container 50. It is rotatably supported. Bearing members are provided at both ends of the rotating shaft 34a. Then, by rotationally driving the first transfer screw 33 and the second transfer screw 34, a circulation path through which the developer circulates is formed 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 developing agent regulating member that regulates the amount of the developing agent carried on the surface of the developing sleeve 70 (also referred to as a developing agent coating amount) is developed. It is attached so as to face the surface of the sleeve 70 in a non-contact manner. The doctor blade 36 has a coating amount regulating surface 36r as a regulating unit that regulates the amount of the developer supported on the surface of the developing sleeve 70. The doctor blade 36 is a resin-made doctor blade molded from a resin. The configuration of the doctor blade 36 (single unit) will be described later with reference to FIG.

The doctor blade 36 is arranged to face the developing sleeve 70 via a predetermined gap (hereinafter referred to as SB gap G) with the developing sleeve 70 in a direction parallel to the rotation axis of the developing sleeve 70. To. In the present invention, the SB gap G is defined as the shortest distance between the maximum image area of the developing sleeve 70 and the maximum image area of the doctor blade 36. The maximum image region of the developing sleeve 70 is a region of the developing sleeve 70 corresponding to the maximum image region of the image regions capable of forming an image on the surface of the photoconductor drum 1 with respect to the rotation axis direction of the developing sleeve 70. That is. Further, the maximum image area of the doctor blade 36 is a doctor blade corresponding to the maximum image area of the image areas capable of forming an image on the surface of the photoconductor drum 1 in a direction parallel to the rotation axis of the developing sleeve 70. It is the area of 36. In the first embodiment, since the photoconductor drum 1 can form an electrostatic latent image of a plurality of sizes, the maximum image region is the most of the image regions of a plurality of sizes that can be formed on the photoconductor drum 1. It is intended to indicate an image area corresponding to a large size (for example, A3 size). On the other hand, in the modified example in which the photoconductor drum 1 can form an electrostatic latent image of only one size, the maximum image region is the image region of one size that can be formed on the photoconductor drum 1. It shall be read as an indication of that.

The doctor blade 36 is arranged so as to substantially face 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 due to the magnetic poles of the magnet roll. Further, the developer regulated by the doctor blade 36 and scraped off tends to stay in the upstream portion of the SB gap G. As a result, a developer pool is formed on the upstream side of the developing sleeve 70 in the rotational direction with respect to the doctor blade 36. Then, a 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 coat amount regulating surface 36r of the doctor blade 36. In this way, a thin layer of the developer is formed on the surface of the developing sleeve 70.

Then, a predetermined amount of the developer supported on the surface of the developing sleeve 70 is conveyed to the developing region as the developing sleeve 70 rotates. Therefore, by adjusting the size of the SB gap G, the amount of the developer transported to the developing region 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 is spiked in the developing area to form magnetic spikes. When the magnetic spikes come into contact with the photoconductor drum 1, the toner in the developer is supplied to the photoconductor drum 1. Then, the electrostatic latent image formed on the surface of the photoconductor 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 toner to the photoconductor drum 1 (hereinafter referred to as the developer after the developing step) is formed between the magnetic poles of the same poles of the magnet roll. It is peeled off from the surface of the developing sleeve 70 by the repulsive magnetic field. The developer after the developing step stripped from the surface of the developing sleeve 70 is collected in the developing chamber 31 by dropping into the developing chamber 31.

As shown in FIG. 4, the developing container 50 is provided with a developing agent guide portion 35 for guiding the developing agent so as to be conveyed toward the SB gap G. The developer guide unit 35 and the developing frame body 30 are integrally formed, and the developer guide unit 35 and the doctor blade 36 are formed separately. The developer guide portion 35 is formed inside the developing frame body 30 and is arranged on the upstream side in the rotation direction of the developing sleeve 70 with respect to the coating amount regulating surface 36r of the doctor blade 36. The developer guide unit 35 stabilizes the flow of the developer and adjusts the density to a predetermined developer density so that the coating amount regulating surface 36r of the doctor blade 36 is in close contact with the surface of the developing sleeve 70. The weight of the developer can be specified.

Further, as shown in FIG. 4, the cover frame body 40 is formed separately from the developing frame body 30 and is attached to the developing frame body 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 region facing the photoconductor drum 1 of the developing sleeve 70 is exposed. The cover frame 40 is fixed to the developing frame 30 by ultrasonic bonding, but the method of fixing the cover frame 40 to the developing frame 30 is any one of screw fastening, snap-fitting, bonding, welding, and the like. It may be a method.

(Construction of resin doctor blade)
The configuration of the doctor blade 36 (single substance) will be described with reference to the perspective view of FIG.

During the image forming operation (development operation), the pressure of the developer generated from the flow of the developer (hereinafter referred to as the agent pressure) is applied to the doctor blade 36. The lower the rigidity of the doctor blade 36, the more easily the doctor blade 36 is deformed and the size of the SB gap G tends to fluctuate when the agent pressure is applied to the doctor blade 36 during the image forming operation. During the image forming operation, the agent pressure is applied to the doctor blade 36 in the lateral direction (direction of arrow M in FIG. 5). Therefore, in order to suppress fluctuations in the size of the SB gap G during the image forming operation, the rigidity of the doctor blade 36 in the lateral direction is increased to be strong against deformation of the doctor blade 36 in the lateral direction. It is desirable to do.

As shown in FIG. 5, the shape of the doctor blade 36 is made into a plate shape from the viewpoint of mass productivity and cost. Further, as shown in FIG. 5, the cross-sectional area of the side surface 36t of the doctor blade 36 is reduced, and the length t ₂ in the thickness direction of the doctor blade 36 is the length t in the lateral direction of the doctor blade 36. It is smaller than ₁ . As a result, the doctor blade 36 (single unit) is easily deformed in a direction orthogonal to the longitudinal direction of the doctor blade 36 (arrow N direction in FIG. 5) (arrow M direction in FIG. 5). Therefore, in order to correct the straightness of the coating amount restricting surface 36r, the doctor blade 36 is bent in the direction of the arrow M in FIG. It is fixed to. The details of the straightness correction of the doctor blade 36 will be described later in FIG.

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

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

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

With the doctor blade 36 attached to the blade mounting portion 41, the adhesive A applied to the blade mounting surface 41s of the blade mounting portion 41 is cured, so that the doctor blade 36 is fixed to the blade mounting portion 41. It is a thing.

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

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

For example, it is assumed that a concentrated load F1 of 300 gf is applied to the central portion 36z of the doctor blade 36 in the longitudinal direction of the doctor blade 36 in the lateral direction of the doctor blade 36. At this time, the amount of bending 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.

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

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

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

It is assumed that a concentrated load F1 of the same magnitude is applied to each of the central portion 36z of the doctor blade 36 and the central portion 41z of the blade mounting portion 41 of the developing frame body 30. At this time, the amount of bending of the central portion 36z of the doctor blade 36 is 10 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 unit) is 10 times or more higher than the rigidity of the doctor blade 36 (single unit). Therefore, in a state where the doctor blade 36 is attached to the blade mounting portion 41 of the developing frame body 30 and the doctor blade 36 is fixed to the blade mounting portion 41 of the developing frame body 30, the developing frame is relative to the rigidity of the doctor blade 36. The rigidity of the body 30 becomes dominant. Further, when the developing frame body 30 is fixed over the entire area of the maximum image area of the doctor blade 36, the developing frame body 30 is fixed as compared with the case where only both ends of the doctor blade 36 in the longitudinal direction are fixed. The rigidity of the doctor blade 36 in the state of being fixed to the doctor blade 36 becomes high.

Further, the magnitude of the rigidity of the developing frame body 30 (single unit) is larger than the magnitude of the rigidity of the cover frame body 40 (single unit). 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 the rigidity of the cover frame 40. Become dominant.

(Correcting the straightness of the resin doctor blade)
In response to an increase in the width of the sheet S, such as the width of the sheet S forming an image being A3 size, an image is displayed on the surface of the photoconductor drum 1 in a direction parallel to the rotation axis of the developing sleeve 70. The length of the maximum image area among the image areas that can be formed increases. Therefore, the length of the maximum image region of the doctor blade 36 increases in response to the increase in the width of the sheet S forming the image. When a doctor blade having a large length in the longitudinal direction is molded from a resin, it is difficult to guarantee the straightness of the coating amount regulation surface of the resin-made doctor blade molded from the resin. This is because, when the doctor blade having a large length in the longitudinal direction is molded from the resin, when the thermally expanded resin is thermally contracted, the heat shrinkage is delayed from the place where the heat shrinkage progresses depending on the position in the longitudinal direction of the doctor blade. This is because it is easy for some parts to occur.

Therefore, in a resin-made doctor blade, as the length of the doctor blade in the longitudinal direction increases, the SB gap tends to differ in the longitudinal direction of the developer carrier due to the straightness of the coating 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 supported on the surface of the developer carrier may be uneven in the longitudinal direction of the developer carrier.

For example, a resin doctor blade whose length in the longitudinal direction corresponds to the A3 size (hereinafter referred to as a resin doctor blade corresponding to the 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 doctor blade made of a resin corresponding to A3 size is manufactured with high accuracy using a highly accurate resin material, the straightness of the coating amount regulation 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, it means that 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 at the maximum. Therefore, regardless of whether the doctor blade made of resin compatible with A3 size is manufactured with the accuracy of a general resin molded product or with high precision using a high precision resin material, the coating amount regulation surface is straight. The accuracy of the degree alone exceeds the allowable range of the tolerance of the SB gap G.

In a developing device equipped with a resin doctor blade, the SB gap G is set to be within a predetermined range in a 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 coating amount regulation surface straightness is used, the SB gap G rotates the developing sleeve 70 by correcting the straightness of the coating amount regulation surface. Keep within a predetermined range in the direction parallel to the axis.

Here, the straightness of the coat amount regulating surface 36r of the doctor blade 36 will be described with reference to the schematic diagram of FIG. The straightness of the coat amount control surface 36r is the maximum value and the minimum value of the outer shape of the coat amount control surface 36r when the predetermined portion of the coat amount control surface 36r in the longitudinal direction of the coat amount control surface 36r is used as a reference. It is expressed as the absolute value of the difference. For example, the central portion of the coat amount regulation surface 36r in the longitudinal direction of the coat amount regulation 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 X axis. Let the straight line be the Y axis. In this Cartesian coordinate system, the straightness of the coat amount regulation 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 coat amount regulation surface 36r.

As shown in FIG. 9, the resin-made doctor blade (single substance) has a shape in which the central portion of the coat amount regulating surface 36r of the doctor blade 36 is greatly 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. 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 consideration of the allowable value of the tolerance of the SB gap G, the mounting accuracy of the doctor blade 36 on the developing frame body 30, and the like. Considering that the accuracy of the straightness of the metal doctor blade is 20 μm or less due to the secondary cutting process, the straightness of the coating amount regulation surface 36r of the resin doctor blade 36 is more preferably 20 μm or less. It is to correct. In consideration of a realistic mass production process, the set value of the straightness correction of the coat amount regulation surface 36r of the doctor blade 36 is set to about 20 μm to 50 μm.

Therefore, a force (also referred to as 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 to bend at least a part of the maximum image area of the doctor blade 36. As a result, the straightness of the coat amount restricting surface 36r of the doctor blade 36 is corrected to 50 μm or less.

In the example of FIG. 9, the outer shape of the tip portion 36e1, 36e5 of the doctor blade 36 is used as a reference, and the outer shape of the tip portion 36e2, 36e3, 36e4 is aligned with the reference. 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 that 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 for fitting the outer shape of the tip portion 36e of the doctor blade 36 is the outer shape of the tip portions 36e1, 36e5 (both ends in the longitudinal direction of the coat amount regulation surface 36r), but the tip portion. The outer shape of 36e3 (the central portion in the longitudinal direction of the coating amount regulating surface 36r) may be used. In that case, the straightness correction force is applied to the doctor blade 36 so that the outer shape of the tip portion 36e3 of the doctor blade 36 is used as a reference and the outer shape of the tip portion 36e1, 36e2, 36e4, 36e5 is aligned with the reference. do.

In this way, in order to correct the straightness of the doctor blade 36, the doctor blade (single unit) is such that at least a part of the maximum image area of the coat amount regulation surface 36r is bent when the straightness correction force is applied to the doctor blade 36. ) Must be low in rigidity.

(How to adjust the SB gap)
The adjustment of the SB gap G is performed with respect to the developing frame 30 so that the relative position of the doctor blade 36 attached to the blade mounting portion 41 is adjusted with respect to the developing sleeve 70 supported by the sleeve supporting portion 42. This is done by moving the position of 36. At a predetermined position of the blade mounting portion 41 determined by adjusting the SB gap G, the doctor blade 36 in which at least a part of the maximum image area of the doctor blade 36 is bent is previously applied to the entire area of the maximum image area of the blade mounting surface 41s. It is fixed by the adhesive A applied over the entire surface. The maximum image region of the blade mounting surface 41s is a blade corresponding to the maximum image region of the image regions capable of forming an image on the surface of the photoconductor drum 1 in a direction parallel to the rotation axis of the developing sleeve 70. It is a region of the mounting surface 41s. At this time, of the maximum image region of the doctor blade 36, the region bent in order to correct the straightness of the coat amount regulating surface 36r is fixed to the blade mounting portion 41. If the region subjected to the force for bending at least a part of the maximum image region of the doctor blade 36 is fixed to the blade mounting portion 41 by the adhesive A, the adhesive is applied to a part of the blade mounting surface 41s. It is assumed that A does not have to be applied. Therefore, the fact that the adhesive A is applied over the entire area of the maximum image region of the blade mounting 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 including the area bent to correct the straightness of the coat amount regulation surface 36r, and the adhesive in the area of 95% or more of the maximum image area of the blade mounting surface 41s. A is applied.

As a result, the region of the maximum image region of the doctor blade 36 that is bent to correct the straightness of the coat amount regulating surface 36r tries to return from the bent state to the original state before bending. It can be suppressed. By doing so, the doctor blade 36 is fixed to the blade mounting portion 41 in a state where the straightness of the coat 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. To measure the size of the SB gap G, the developing sleeve 70 is supported by the sleeve support portion 42 of the developing frame body 30, the doctor blade 36 is attached to the blade mounting portion 41 of the developing frame body 30, and the cover frame body is used. 40 is fixed to the developing 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 in the longitudinal direction of the developing chamber 31. The light source inserted in the developing chamber 31 irradiates light from the inside of the developing chamber 31 toward the SB gap G. Further, cameras for capturing light rays emitted from the SB gap G to the outside of the developing frame 30 are arranged at each of the five locations corresponding to the tip portions 36e (36e1 to 36e5) of the doctor blade 36.

The cameras arranged at these five locations capture the light rays emitted from the SB gap G to the outside of the developing frame 30 in order to measure the positions of the tip portions 36e (36e1 to 36e5) of the doctor blade 36, respectively. At this time, the camera reads the position where the developing sleeve 70 is in close contact with 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. Subsequently, the pixel value is converted into a distance from the image data read by the camera and generated, and the size of the SB gap G is calculated. If the calculated size of the SB gap G is not within the predetermined range, the SB gap G is adjusted. Then, when the calculated size of the SB gap G is within a predetermined range, the doctor blade 36 having at least a part of the maximum image area of the doctor blade 36 bent is fixed to the blade mounting portion 41 of the developing frame body 30. Determined as a position.

By the method described below, it is determined whether the SB gap G is within a predetermined range in the direction parallel to the rotation axis of the developing sleeve 70. First, the maximum image area of the doctor blade 36 is divided into four or more at equal intervals, and the SB gap is formed at each division of the doctor blade 36 (including both ends and the center of the maximum image area of the doctor blade 36). Measure G at 5 or more points. 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 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 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 assumed 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. Anything above that is fine. 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 frame 30 due to 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 the heat generated during the developing operation, for example, the heat generated when the rotating shaft of the developing sleeve 70 and the bearing 71 rotate, the heat generated when the rotating shaft 33a of the first transfer screw 33 and its bearing member rotate, and the SB gap G. There is heat generated when the developer passes through. These heats generated during the image forming operation change the temperature around the developing device 3, and also change the temperatures of the doctor blade 36, the developing frame body 30, and the cover frame body 40.

As shown in FIG. 10, the elongation amount of the doctor blade 36 due to the 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 the temperature change is I [μm]. Further, it is assumed that the linear expansion coefficient of the resin constituting the doctor blade 36 and the linear expansion coefficient of the resin constituting 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 the temperature change is different due to the difference in these linear expansion coefficients, and in order to fill the difference between H [μm] and I [μm], the doctor blade 36 is shown in the figure. It is deformed in the direction of the arrow J of 10. The deformation of the doctor blade 36 in the direction of arrow J in FIG. 10 is hereinafter referred to as the deformation of the doctor blade 36 in the warping direction. Then, the deformation of the doctor blade 36 in the warping direction leads to the fluctuation of the size of the SB gap G. In order to suppress fluctuations in the size of the SB gap G due to heat, the linear expansion coefficient α2 of the resin constituting the sleeve support portion 42 and the blade mounting portion 41 of the developing frame body 30 (single substance), and the doctor blade 36 Each of the linear expansion coefficients α1 of the resin constituting (elementary substance) 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 amount of deformation due to the temperature change is different due to the difference in these linear expansion coefficients. ..

Generally, 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 due to a temperature change due to heat generated during the image forming operation, and the central portion of the doctor blade 36 in the longitudinal direction tends to bend. As a result, in the developing apparatus in which the resin doctor blade 36 is fixed to the resin developing frame, 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 controlling 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 maximum image region of the doctor blade 36 is bent is applied to the blade mounting portion 41 of the developing frame 30 over the entire area of the maximum image region of the doctor blade 36. The method of fixing by is adopted.

At this time, if there is a large difference between the heat ray expansion coefficient α2 of the resin constituting the developing frame 30 and the heat ray expansion coefficient α1 of the resin constituting the doctor blade 36, the following problems will occur when a temperature change occurs. be. That is, when a temperature change occurs, the amount of deformation (stretching amount) of the doctor blade 36 due to the temperature change and the amount of deformation (stretching amount) of the developing frame 30 due to the temperature change are different. As a result, even if the SB gap G is adjusted with high accuracy when determining the position where the doctor blade 36 is mounted on the blade mounting surface 41s of the developing frame body 30, the SB gap G is caused by the temperature change during the image forming operation. It will fluctuate the size.

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

The difference in the linear expansion coefficient α2 of the resin constituting the developing frame 30 having the sleeve support portion 42 and the blade mounting portion 41 with respect to the linear expansion coefficient α1 of the resin constituting the doctor blade 36 is referred to thereafter as the linear expansion coefficient difference α2-. Called α1. The change in the maximum deflection amount of the doctor blade 36 due to the linear expansion coefficient difference α2-α1 will be described with reference to Table 1. A temperature change from normal temperature (23 ° C.) to high temperature (40 ° C.) is performed in a state where the doctor blade 36 is fixed to the blade mounting portion 41 of the developing frame 30 over the entire maximum image area of the doctor blade 36. The maximum amount of bending of the doctor blade 36 at the time of feeding was measured.

The linear expansion coefficient of the resin constituting the developing frame 30 having the sleeve support portion 42 and the blade mounting portion 41 is α1 [m / ° C], and the linear expansion coefficient of the resin constituting the doctor blade 36 is α2 [m / ° C]. do. Table 1 shows the results of measuring the maximum deflection amount of the doctor blade 36 by changing the parameters of the linear expansion coefficient difference α2-α1. In Table 1, when the absolute value of the maximum bending amount of the doctor blade 36 is 20 μm or less, the maximum bending amount is set to “〇”, and when the absolute value of the maximum bending amount of the doctor blade 36 is larger than 20 μm, the maximum bending amount is set. The 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 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.
(Equation 1)
-0.45 x ^10-5 [m / ° C] ≤ α2-α1 ≤ 0.55 x ^10-5 [m / ° C]

Therefore, the developing 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. The resin and the resin constituting the doctor blade 36 may be selected. When the same resin as the resin constituting the developing frame body 30 and the resin constituting the doctor blade 36 are selected, the linear expansion coefficient difference α2-α1 becomes zero.

When the adhesive A is applied to the doctor blade 36 and the developing frame body 30, the linear expansion coefficient of the doctor blade 36 and the developing frame body 30 to which the adhesive A is applied fluctuates. However, the volume of the adhesive A applied to the doctor blade 36 and the developing frame 30 itself is very small, and the influence on the dimensional variation of the adhesive A in the thickness direction due to the temperature change 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 due to the fluctuation of the linear expansion coefficient difference α2-α1 is negligible. 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 a temperature change is different, the deformation of the cover frame 40 in the warp direction is caused. 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 support portion 42 and the blade mounting portion 41 is α2 [m / ° C], and the linear expansion coefficient of the resin constituting the cover frame 40 is α3 [m / ° C]. And. Then, the difference in the linear expansion coefficient α3 of the resin constituting the cover frame 40 with respect to the linear expansion coefficient α2 of the resin constituting the developing frame body 30 having the sleeve support portion 42 and the blade mounting portion 41 is hereinafter referred to as the linear expansion coefficient. It is called the difference α3-α2. At this time, it is necessary to satisfy the following relational expression (Equation 2) for the linear expansion coefficient difference α3-α2 in the same manner as in Table 1.
(Equation 2)
-0.45 x ^10-5 [m / ° C] ≤ α3-α2 ≤ 0.55 x ^10-5 [m / ° C]

Therefore, the developing frame 30 is configured so 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 constituting the cover frame 40 may be selected. When the same resin as the resin constituting the developing frame body 30 and the resin constituting the cover frame body 40 are selected, 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 applied to the doctor blade 36 during the image forming operation will be described with reference to the cross-sectional view of FIG. FIG. 11 is a cross-sectional view of the developing apparatus 3 in a cross section orthogonal to the rotation axis of the developing sleeve 70 (cross section H in FIG. 2). Further, FIG. 11 shows a configuration in the vicinity of the doctor blade 36 fixed by the adhesive A to the blade mounting portion 41 of the developing frame body 30.

As shown in FIG. 11, the line connecting the closest position of the doctor blade 36 with the developing sleeve 70 on the coating amount regulating surface 36r and the rotation center 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 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 portion 30a of the developing frame 30 located in the vicinity of the developer guide portion 35 is small. ..

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

During the image forming operation, the developer pumped up from the first transfer screw 33 passes through the developer guide unit 35 and is conveyed to the surface of the developing sleeve 70. After that, even when the layer thickness of the developer is defined by 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 applied to the blade mounting surface 41s 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 of peeling the doctor blade 36 from the blade mounting surface 41s. Therefore, the bonding force due to the adhesive A needs to be sufficiently large with respect to the agent pressure in the Y-axis direction. Therefore, the adhesive area and coating thickness of the adhesive A to the blade mounting surface 41s are optimized in consideration of the force of peeling the doctor blade 36 from the blade mounting surface 41s by the agent pressure and the adhesive force of the adhesive A. It has become.

(Structure of the developing apparatus according to the first embodiment)
As described above, the length of the maximum image region of the doctor blade 36 in the longitudinal direction increases in accordance with the increase in the width of the sheet S forming the image. When the doctor blade 36 having a large length in the longitudinal direction is molded from resin, it is difficult to guarantee the straightness of the coating amount regulating surface 36r of the resin doctor blade 36. Therefore, in the first embodiment, in order to correct the straightness of the coat amount restricting surface 36r of the doctor blade 36 having a large length in the longitudinal direction to 50 μm or less, at least a part of the maximum image area of the doctor blade 36 is flexed. No. Then, a method is adopted in which the doctor blade 36 in which at least a part of the maximum image region of the doctor blade 36 is bent is attached to the blade mounting portion 41 of the developing frame body 30 and fixed by the adhesive A.

As a result, the region of the maximum image region of the doctor blade 36 that is bent to correct the straightness of the coat amount regulating surface 36r tries to return from the bent state to the original state before bending. It can be suppressed. Therefore, in order to prevent the bending of the doctor blade 36 from returning to its original state, the doctor blade 36 may be fixed to the blade mounting portion 41 with the adhesive A over substantially the entire maximum image area of the doctor blade 36. desirable.

In the first embodiment, in the configuration in which the resin doctor blade 36 is attached to the blade mounting portion 41 of the resin developing frame 30 and fixed by the adhesive A, the adhesive A having a predetermined film thickness is, for example, , 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 bonding), a predetermined pressure is applied to the doctor blade 36, so that the adhesive A having a predetermined film thickness is crushed. At this time, the adhesive (excessive adhesive) that has escaped to the outside of the surface to which the adhesive A is applied (here, the blade mounting surface 41s) may invade the inside of the developing frame 30. When this excess adhesive adheres to the developer guide portion 35 of the developing frame 30 and is cured, there is a possibility that the flow of the developer conveyed toward the SB gap G will fluctuate. In such a case, the amount of the developer supported on the surface of the developing sleeve 70 may be uneven in the longitudinal direction of the developing sleeve 70.

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

The configuration of the developing apparatus according to the first embodiment will be described with reference to 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 apparatus 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 apparatus 300 in a cross section orthogonal to the rotation axis of the developing sleeve 70, in the vicinity of the blade mounting portion 410 (particularly, the blade mounting surface 410s) of the developing frame 310 (region I in FIG. 12). It is an enlarged view of the developing apparatus 300 in). In FIGS. 12 and 13, those with the same reference numerals as those in FIG. 4 show the same configuration. In the configuration of the developing apparatus 300 according to the first embodiment, the differences from the configuration of the developing apparatus 3 described above with reference to FIG. 4 will be mainly described.

As shown in FIGS. 12 and 13, the blade mounting portion 410 is provided with a first blade support portion 420 and a second blade support portion 430 for supporting the doctor blade 36, which project from the developing frame body 310, via intervals. It is provided. Further, the blade mounting surface 410s is the first blade support surface 420s of the first blade support portion 420 that supports the doctor blade 36, and the second blade support surface 430s of the second blade support portion 430 that supports the doctor blade 36. It is composed of and. The shortest distance between the developing sleeve 70 and the second blade support surface 430s is longer than the shortest distance between the developing sleeve 70 and the first blade support surface 420s.

In the first embodiment, the first blade support surface 420s is formed over substantially the entire maximum image area of the blade mounting surface 410s. Further, in the first embodiment, the second blade support surface 430s is formed over substantially the entire maximum image region of the blade mounting surface 410s. As a result, the posture of the doctor blade 36 supported by the first blade support surface 420s and the second blade support surface 430s and attached to the blade mounting portion 410 can be stabilized. If each of the first blade support surface 420s and the second blade support surface 430s is formed over 90% or more of the maximum image area of the blade mounting surface 410s, the maximum image area of the blade mounting surface 410s. It is considered that it is formed over almost the entire area of.

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

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

In the first embodiment, for example, the length of the second blade support surface 430s in the lateral direction is 1.5 [mm], and the height of the adhesive A applied to the second blade support surface 430s is 800 [μm]. ]. Further, in the first embodiment, for example, the distance between the first blade support portion 420 and the second blade support portion 430 (that is, the width of the groove portion 440) is set to 3.5 [mm]. Further, in the first embodiment, for example, the amount of dent (that is, the depth of the groove portion 440) from the blade mounting surface 410s (each of the first blade support surface 420s and the second blade support surface 430s) is 0.4 [. mm]. Further, 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 20 to a film thickness capable of ensuring 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 portion 440 is larger than the volume of the adhesive A applied to the second blade support surface 430s. Specifically, the total area of the area where the adhesive A is applied to the blade mounting surface 410s (here, the second blade support surface 430s) is set to S ₁ [mm ² ], and the second blade support surface 430s is used. Let t [mm] be the film thickness of the adhesive A when the applied adhesive A is cured. At this time, the volume of the adhesive A applied to the second blade support surface 430s is S ₁ × t [mm ³ ]. Further, the length of the groove portion 440 in the longitudinal direction is L [mm], and the cross-sectional area of the groove portion 440 in the 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 portion 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 portion 440 is the volume of the adhesive A applied to the second blade support surface 430s. Means larger than.

By satisfying such a relationship, all of the adhesive A having a predetermined film thickness applied to the blade mounting surface 410s (here, the second blade support surface 430s) is outside the second blade support surface 430s. Even if it escapes to, all of the adhesive A is accumulated in the groove portion 440. Therefore, since the excess adhesive does not invade the inside of the developing frame 310, the excess adhesive is conveyed toward the SB gap G, in particular, by adhering to the developing agent guide portion 35 and hardening. There is no risk of fluctuations in the flow of the developer.

In order to prevent the excess adhesive from entering the inside of the developing frame 310, the adhesive A is applied to the second blade support surface 430s, which is far from the developing sleeve 70, but the developing sleeve 70. It is desirable not to apply it to the first blade support surface 420s, which is close to the blade. 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 mounting portion 410, a part of the adhesive that escapes to the outside of the first blade support surface 420s is released. This is because there is a possibility of invading the inside of the developing frame body 310. On the other hand, when the doctor blade 36 is attached to the blade mounting portion 410, it is assumed that all of the adhesive A having a predetermined film thickness applied to the second blade support surface 430s escapes 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), it is possible to prevent the adhesive that has escaped to the outside of the second blade support surface 430s from entering the inside of the developing frame 310. 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) that has escaped to the outside of the surface to which the adhesive A is applied is provided. An example in which the groove portion for forming is provided on the blade mounting portion side has been described. 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) that has escaped to the outside of the surface to which the adhesive A is applied is provided. An example in which a groove for forming is provided on the doctor blade side will be described.

The configuration of the developing apparatus according to the second embodiment will be described with reference to 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 apparatus 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 enlargement of the developing device 301 in the vicinity of the blade mounting portion 41 (particularly, the blade mounting surface 41s) of the developing frame body 30. It is a figure. In FIGS. 14 and 15, those having the same reference numerals as those in FIGS. 4, 12, and 13 show the same configuration. In the configuration of the developing apparatus 301 according to the second embodiment, the differences from the configuration of the developing apparatus 300 described above with reference to FIGS. 12 and 13 will be mainly described.

In the doctor blade 360, the first blade contact portion 370 and the second blade contact portion 380, which are the portions where the doctor blade 360 contacts the blade mounting portion 41 when the doctor blade 360 is attached to the blade mounting portion 41, are interposed. It 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 is the first blade contact portion 370. It is formed between the second blade contact portion 380 and the second blade contact portion 380. The first blade contact surface 370s is the surface of the first blade contact portion 370 that contacts the blade mounting portion 41, and the second blade contact surface 380s is the surface of the second blade contact portion 380 that contacts the blade mounting portion 41. It is the surface that comes into contact. The groove portion 390 is a predetermined space for accumulating the adhesive (excess adhesive) that 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 (at the time of adhesion). It plays a role as.

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

In such a second embodiment, the volume (volume) of the groove portion 390 is larger than the volume of the adhesive A applied to the second blade contact surface 380s. By satisfying such a relationship, all of the adhesive A having a predetermined film thickness applied to the doctor blade 360 (here, the second blade contact surface 380s) is moved to the outside of the second blade contact surface 380s. Even if it escapes, all of the adhesive A is accumulated in the groove portion 390. Therefore, since the excess adhesive does not invade the inside of the developing frame 30, the excess adhesive is conveyed toward the SB gap G, in particular, by adhering to the developing agent guide portion 35 and hardening. There is no risk of fluctuations in the flow of the developer.

In order to prevent the excess adhesive from entering the inside of the developing 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 it to the first blade contact surface 370s, which is close to 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 mounting portion 41, a part of the adhesive that escapes to the outside of the first blade contact surface 370s is removed. This is because there is a possibility of invading the inside of the developing frame body 30. On the other hand, when the doctor blade 360 is attached to the blade attachment portion 41, it is assumed that 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 portion 390. Therefore, when the doctor blade 360 is attached to the blade attachment portion 41 (during adhesion), it is possible to prevent the adhesive that has escaped to the outside of the second blade contact surface 380s from entering the inside of the developing frame body 30. can.

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

The configuration of the developing apparatus according to the third embodiment will be described with reference to 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 enlargement of the developing device 302 in the vicinity of the blade mounting portion 410 (particularly, the blade mounting surface 410s) of the developing frame body 310. It is a figure. In FIG. 16, those with the same reference numerals as those in FIGS. 13 and 15 show the same configuration. In the configuration of the developing device 302 according to the third embodiment, the configuration of the developing device 300 described above in FIG. 13 and the configuration of the developing device 301 described above in FIG. 15 will be mainly described.

In the third embodiment, as shown in FIG. 16, the groove portion 440 as a recessed portion recessed by 0.2 [mm] or more from each of the first blade support surface 420s and the second blade support surface 430s is the first blade. It is formed between the support portion 420 and the second blade support portion 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 third. It is formed between the 1-blade contact portion 370 and the 2nd blade contact portion 380.

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

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

In such a third embodiment, the total volume (volume) of the groove portion 440 of the blade mounting 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, all of the adhesive A applied to the second blade support surface 430s and the second blade contact surface 380s is tentatively moved 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 accumulated in the groove portion 440 and the groove portion 390. Therefore, since the excess adhesive does not invade the inside of the developing frame 310, the excess adhesive is conveyed toward the SB gap G, in particular, by adhering to the developing agent guide portion 35 and hardening. There is no risk of fluctuations in the flow of the developer.

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

On the other hand, in the fourth embodiment, neither the blade mounting portion nor the doctor blade is provided with a groove portion for forming a predetermined space for accumulating excess adhesive in advance. Instead, in the fourth embodiment, when the doctor blade is attached to the blade attachment portion, a predetermined adhesive (excess adhesive) for accumulating the adhesive (excess adhesive) that has escaped to the outside of the surface to which the adhesive A is applied is stored. An example in which a space is formed for the first time will be described.

The configuration of the developing apparatus according to the fourth embodiment will be described with reference to 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 enlargement of the developing device 302 in the vicinity of the blade mounting portion 4100 (particularly, the blade mounting surface 4100s) of the developing frame body 3100. It is a figure. In FIG. 17, those with the same reference numerals as those in FIGS. 13, 15, and 16 show the same configuration. 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, and the configuration of the developing device 302 described above in FIG. I will mainly explain about this.

As shown in FIG. 17, when the doctor blade 3600 is attached to the blade mounting portion 4100, a predetermined space (3900) for collecting the adhesive that has escaped to the outside of the adhesive coating surface is provided with the blade mounting 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 larger than the volume of the adhesive A applied to the blade mounting portion 4100 or the doctor blade 3600. It's getting bigger. By satisfying such a relationship, even if all of the adhesive A applied to the blade mounting portion 4100 and the doctor blade 3600 escapes to the outside of the surface to which the adhesive A is applied, the adhesive A Everything is stored in a predetermined space (3900) for storing excess adhesive. Therefore, since the excess adhesive does not invade the inside of the developing frame 3100, the excess adhesive is conveyed toward the SB gap G, in particular, by adhering to the developing agent guide portion 35 and hardening. There is no risk of fluctuations in the flow of the developer.

(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 these are excluded from the scope of the present invention. is not it.

In the above embodiment, as shown in FIG. 1, an image forming apparatus 60 having a configuration in which the intermediate transfer belt 61 is used as an intermediate transfer body 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 a recording material is brought into direct contact with the photoconductor drum 1 in order to perform 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 unitized and attached to and detached from the image forming device 60. The same effect can be obtained even in the form of a cartridge. Further, as long as the image forming apparatus 60 is provided with the developing apparatus 300 or the process cartridge, the present invention can be applied regardless of whether it is a monochrome machine or a color machine.

36 Doctor blade 70 Develop sleeve 300 Develop device 310 Develop frame body 410 Blade mounting part 440 Groove part

Claims (4)

A developer carrier that is rotatably supported and carries a developer containing toner and carriers to develop an electrostatic latent image formed on the image carrier .
A resin-made regulating blade , which is arranged so as to face the developer carrier in a non- contact manner and regulates the amount of the developer supported on the developer carrier.
A resin developing frame body having a mounting portion for mounting the regulation blade, and
Equipped with
The mounting portion includes a first support portion that protrudes from the developing frame and has a first support surface for supporting the regulating blade, and a first support portion that protrudes from the developing frame and supports the regulating blade. Each of the second support portions having the two support surfaces is provided with a gap between them.
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.
With the regulatory blade supported by the first support surface and supported by the second support surface, the regulatory blade corresponds to a maximum image region capable of forming an image on the image carrier. The area is adhered to the second support portion with an adhesive and is not adhered to the first support portion .
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. Ori,
A developing apparatus characterized in that a predetermined space for accumulating the adhesive is formed between the recessed portion and the regulating blade. Each of the first support surface and the second support surface is formed over substantially the entire region corresponding to the maximum image region in which an image can be formed on the image carrier.
The recess is formed between the first support and the second support over substantially the entire area corresponding to the maximum image region in which an image can be formed on the image carrier. ,
The predetermined space is formed between the recess and the restricting blade over substantially the entire area corresponding to the maximum image region in which an image can be formed on the image carrier. The developing apparatus according to claim 1 . The regulatory blade is within a predetermined range over substantially the entire area of the region where the gap between the developer carrier and the regulatory blade corresponds to the maximum image region capable of forming an image on the image carrier. Claim 1 is characterized in that a region corresponding to a maximum image region capable of forming an image on the image carrier is adhered to the second support portion by the adhesive in a state of being bent so as to be. Or the developing apparatus according to 2 . 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 apparatus according to claim 3 , wherein the absolute value of is within a range satisfying that it is 10% or less of the median value of the gap.

Images