JP2008051875A - Developing device and image forming apparatus having the same - Google Patents

Abstract

A developing device and an image forming apparatus provided with the developing device that can uniformly regulate the layer thickness of a developer carried on the surface of a developing roller.
In a state in which the developing roller is held in the housing, the pressure contact rubber is brought into contact with the pressure in the axial direction of the developing roller and the developing roller is removed from the housing. The support member 53 is fixed to both blade fixing portions 104 formed on the fixing wall 103 of the housing 36 so that the layer thickness regulating blade 40 bends toward the position where the developing roller 39 is disposed.
[Selection] Figure 7

Description

  The present invention relates to an image forming apparatus such as a laser printer and a developing device provided in the image forming apparatus.

In the image forming apparatus, an electrostatic latent image is formed on the surface of the photosensitive drum, and toner is supplied to the electrostatic latent image from the developing device, whereby the toner image is carried on the surface of the photosensitive drum. Then, the toner image is transferred onto the sheet, whereby the formation of the image on the sheet is achieved.
The developing device includes a housing having an opening that opens toward the photosensitive drum, a developing roller that carries toner accommodated in the housing, and a layer thickness of the toner carried on the developing roller. And a layer thickness regulating blade. The developing roller is rotatably supported in a state where a part of the surface is exposed at the opening of the housing. The layer thickness regulating blade includes a support member having both ends in the longitudinal direction (axial direction of the developing roller) fixed to the housing by screws, a leaf spring member supported by the supporting member and extending toward the developing roller, and a plate And a pressing portion having a semicircular cross section that is provided at the tip of the spring member and is pressed against the surface of the developing roller. The toner in the housing is supplied onto the surface of the developing roller, and passes between the pressing portion of the layer thickness regulating blade and the surface of the developing roller as the developing roller rotates, and is a thin layer having a constant thickness. And is carried on the surface of the developing roller. The toner carried on the surface of the developing roller is supplied to an electrostatic latent image formed on the surface of the photosensitive drum when it contacts the surface of the photosensitive drum (see, for example, Patent Document 1).
JP 2002-287487 A

  However, in the configuration in which both end portions in the longitudinal direction of the support member are fixed to the housing by screws, the central portion in the longitudinal direction of the support member may bend in the direction in which the pressing portion is separated from the surface of the developing roller. When the support member is bent in this manner, the leaf spring member is bent along with the bending, and the pressing portion is not uniformly pressed against the developing roller in the axial direction. As a result, the layer thickness of the toner carried on the surface of the developing roller is not uniform, and streaks due to undesired density unevenness may occur in the image formed on the paper.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device and an image forming apparatus provided with the developing device that can uniformly regulate the layer thickness of the developer carried on the surface of the developing roller.

  In order to achieve the above object, the invention described in claim 1 includes a housing, a developing roller held in the housing and carrying a developer, and a layer thickness of the developer carried on the developing roller. A developing device comprising a layer thickness regulating blade for regulating, wherein the layer thickness regulating blade is formed in a longitudinal shape extending in the axial direction of the developing roller, and is attached to the housing; and the support A state in which the developing roller is held by the housing, the plate spring member extending from the member toward the developing roller; and a contact portion provided at a tip of the leaf spring member and contacting the developing roller The layer thickness regulating blade is directed toward the position where the developing roller is disposed in a state where the contact portion contacts with a uniform pressure in the axial direction of the developing roller and the developing roller is removed from the housing. To bend Serial support member is characterized by being attached to the housing.

  According to a second aspect of the present invention, in the first aspect of the invention, the casing is provided to face each end portion in the longitudinal direction of the support member, and each end portion in the longitudinal direction of the support member that faces the support member. Is fixed between the blade fixing portion and the blade fixing portion, is interposed between the casing and the support member, and the developing roller is removed from the casing, An elastic member that protrudes closer to the position where the developing roller is disposed than a surface of the blade fixing portion facing the support member is provided.

According to a third aspect of the present invention, in the second aspect of the present invention, the elastic member is a blade seal that seals between the housing and the support member.
According to a fourth aspect of the present invention, in the first aspect of the present invention, the casing is provided to face each end in the longitudinal direction of the support member, and the inner side in the longitudinal direction is closer to the support member. A protruding amount is formed large, and a blade fixing portion to which each end portion in the longitudinal direction of the opposing support member is fixed is provided.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects of the present invention, the casing is provided to face each end in the longitudinal direction of the support member. A blade fixing portion to which each end in the longitudinal direction is fixed is provided, and the length of the supporting member is longer than the interval between the blade fixing portions.
The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the support member and the leaf spring member are interposed between the support member and the leaf spring member by bonding. And an adhesive layer for fixing.

A seventh aspect of the invention is characterized in that, in the sixth aspect of the invention, the adhesive layer is a double-sided tape in which an adhesive is applied on both sides.
The invention according to claim 8 is the invention according to claim 6 or 7, wherein the contact portion is visible from the outside of the casing in a state where the developing roller is held by the casing. It is characterized by.

  According to a ninth aspect of the present invention, there is provided an image forming apparatus comprising: the developing device according to any one of the first to eighth aspects; and an image carrier to which a developer is supplied from the developing roller. It is said.

  According to the first aspect of the present invention, the support member bends toward the position where the developing roller is disposed in a state where the developing roller is removed from the housing. When the developing roller is held by the housing, the contact portion is pushed by the developing roller, the support member is bent, and the contact portion is applied to the developing roller with a uniform pressure in the axial direction. Touch. Therefore, the layer thickness of the developer carried on the surface of the developing roller can be regulated uniformly.

  According to the second aspect of the invention, the blade fixing portion to which each end portion in the longitudinal direction of the support member is fixed is provided in the casing, and the elastic member is disposed between the blade fixing portions. The elastic member protrudes closer to the position where the developing roller is disposed than the surface of the blade fixing portion facing the support member in a state where the developing roller is removed from the housing. Therefore, the supporting member can be reliably bent toward the position where the developing roller is disposed in a state where the developing roller is removed from the housing. When the developing roller is held by the housing, the contact portion is pushed by the developing roller, and the elastic member is elastically deformed by the pressing force, and the bending of the support member is corrected. The roller abuts with a uniform pressure in the axial direction. Therefore, the layer thickness of the developer carried on the surface of the developing roller can be regulated uniformly.

According to the third aspect of the present invention, since the elastic member is a blade seal, the support member can be reliably bent toward the position where the developing roller is disposed, and the space between the housing and the support member can be increased. From the developer can be prevented.
According to the invention described in claim 4, the casing is provided with the blade fixing portion to which each end portion in the longitudinal direction of the support member is fixed. Each blade fixing portion is formed such that the protruding amount in the direction facing the support member is larger toward the inner side in the longitudinal direction of the support member. Therefore, by fixing each end portion in the longitudinal direction of the support member to each blade fixing portion, the support member can be reliably bent toward the position where the developing roller is disposed.

According to the invention described in claim 5, the blade fixing portion to which each end portion in the longitudinal direction of the support member is fixed is provided in the casing, and the length in the longitudinal direction of the support member is the distance between the blade fixing portions. Longer than. Therefore, by fixing each longitudinal end portion of the support member to each blade fixing portion, the support member can be reliably bent toward the position where the developing roller is disposed.
According to the invention described in claim 6, the support member and the leaf spring member are fixed to each other by adhesion via the adhesive layer. In the configuration in which the support member and the leaf spring member are fixed to each other with screws, a local force acts on the portion of the leaf spring member through which the screw penetrates, so that the leaf spring member is deformed to wave, and the contact portion is There is a possibility that the developing roller may not be contacted with a uniform pressure in the axial direction. On the other hand, in the configuration in which the support member and the leaf spring member are fixed to each other by bonding, there is no such deformation of the leaf spring member, and the abutting portion abuts against the developing roller with uniform pressure in the axial direction. Can be made. Therefore, the layer thickness of the developer carried on the surface of the developing roller can be regulated more uniformly.

According to the invention described in claim 7, since the adhesive layer is a double-sided tape, one side of the double-sided tape is attached to one of the support member and the leaf spring member, and the other of them is attached to the other side of the double-sided tape. By a simple operation of bonding, the adhesive layer can be reliably arranged at a predetermined position.
According to the eighth aspect of the present invention, the abutting portion that abuts against the developing roller can be visually recognized from the outside of the casing while the developing roller is held by the casing. Therefore, it is possible to easily confirm the presence or absence of developer leakage from the vicinity of both ends in the longitudinal direction of the contact portion.

  According to the invention described in claim 9, since the developing device according to any one of claims 1 to 8 is provided, the layer thickness of the developer carried on the surface of the developing roller can be uniformly regulated. it can. As a result, it is possible to achieve a good supply of developer from the developing roller to the image carrier.

1. 1 is a side sectional view showing an embodiment of a color laser printer as an example of an image forming apparatus of the present invention.
The color laser printer 1 is a horizontal tandem color laser printer in which a plurality of photosensitive drums 29 to be described later are arranged in parallel in the horizontal direction.

In the color laser printer 1, an image is formed in a main body casing 2, a paper feeding unit 4 for feeding paper 3, an image forming unit 5 for forming an image on the fed paper 3, and an image. A paper discharge unit 6 for discharging the printed paper 3.
(1) Main Body Casing The main body casing 2 is formed in a box shape having a substantially rectangular shape when viewed from the side, and includes a drum unit 25 to be described later.

In the following description, the right side in FIG. 1 is the front side (front side), and the left side in FIG. 1 is the rear side (back side). Further, when the color laser printer 1 is viewed from the front side, the left and right reference is used. The left-right direction and the width direction are the same direction. Further, the drum unit 25 and the developing cartridge 27 described later will be described with reference to the direction in the mounted state with respect to the main casing 2 unless otherwise specified.
(2) Paper Feed Unit The paper feed unit 4 includes a paper feed tray 10 that is detachably attached to the bottom of the main body casing 2. A paper feed roller 11 is disposed above the front end of the paper feed tray 10. Further, the paper feed unit 4 includes a substantially U-shaped paper feed path 17 formed between the front end portion of the paper feed tray 10 and a conveyance belt 58 described later. On the paper feed path 17, a separation roller 12, a separation pad 13, a pinch roller 14, a paper dust removing roller 15, and a pair of registration rollers 16 are disposed.

The paper 3 stacked in the paper feed tray 10 is sent out to the paper feed path 17 by the rotation of the paper feed roller 11. The fed paper 3 is fed one by one between the separation roller 12 and the separation pad 13. Then, the paper 3 passes between the pinch roller 14 and the paper dust removing roller 15, and after the paper dust is removed by the paper dust removing roller 15, the paper 3 is conveyed to the registration roller 16. The registration roller 16 sends out the paper 3 onto a conveyance belt 58 described later after registration.
(3) Image Forming Unit The image forming unit 5 includes a scanner unit 20, a process unit 21, a transfer unit 22, and a fixing unit 23.
(3-1) Scanner Unit The scanner unit 20 is disposed on the upper part of the main body casing 2. The scanner unit 20 includes optical members such as a laser, a mirror, and a lens, and emits four laser beams toward four photosensitive drums 29 described later.
(3-2) Process Unit The process unit 21 is disposed below the scanner unit 20 and above the paper feed unit 4. The process unit 21 includes one drum unit 25 and a developing cartridge 27 as an example of four developing devices corresponding to black, yellow, magenta, and cyan colors.
(3-2-1) Drum Unit The drum unit 25 includes four photosensitive drums 29, scorotron chargers 30 and four cleaning brushes 31 as an example of an image carrier corresponding to each color.

The photosensitive drum 29 has a cylindrical shape whose outermost layer is formed of a positively chargeable photosensitive layer, and is rotated by a driving force from a motor (not shown) provided in the main body casing 2 during image formation.
The scorotron charger 30 is disposed obliquely above and rearward of the photosensitive drum 29 with a distance from the photosensitive drum 29, and the surface of the photosensitive drum 29 is uniformly charged positively during image formation. .

The cleaning brush 31 is disposed behind the photosensitive drum 29 so as to face and contact the photosensitive drum 29, and a cleaning bias is applied during image formation.
(3-2-2) Developing Cartridge FIG. 2 is a side sectional view of the developing cartridge 27.

As shown in FIG. 2, each developing cartridge 27 corresponding to each color photosensitive drum 29 includes an agitator 37, a supply roller 38, a developing roller 39, and a layer thickness regulating blade 40 in a housing 36.
The housing 36 is formed in a box shape having an opening 41 at the lower end. The interior of the housing 36 is partitioned by a partition wall 42 into an upper toner storage chamber 43 and a lower development chamber 44. The partition wall 42 is formed with a communication port 45 that allows the toner storage chamber 43 and the development chamber 44 to communicate with each other.

The toner storage chamber 43 stores toner as a color developer corresponding to each developing cartridge 27. As the toner of each color, a positively chargeable non-magnetic one-component polymer toner in which yellow, magenta, cyan, and black colorants are blended corresponding to each color is used.
The agitator 37 is provided in the toner storage chamber 43. The agitator 37 includes an agitator rotating shaft 47 that is rotatably supported on both side walls 101 of the housing 36, and a stirring member 48 that extends radially outward from the agitator rotating shaft 47. At the time of image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted to the agitator rotating shaft 47, and the agitating member 48 moves around in the toner storage chamber 43.

  The supply roller 38 is provided below the communication port 45 in the developing chamber 44. The supply roller 38 includes a metal supply roller shaft 49 that is rotatably supported on both side walls 101 of the housing 36, and a sponge roller 50 made of a conductive sponge that covers the supply roller shaft 49. Yes. At the time of image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted, and the supply roller 38 is rotated.

  The developing roller 39 is provided in the developing chamber 44 obliquely rearward and downward with respect to the supply roller 38. The developing roller 39 includes a metal developing roller shaft 51 that is rotatably supported on both side walls 101 of the housing 36, and a rubber roller 52 made of conductive rubber that covers the developing roller shaft 51. . A part of the peripheral surface of the rubber roller 52 is exposed downward from the opening 41 of the developing chamber 44. The rubber roller 52 is in pressure contact with the sponge roller 50 of the supply roller 38. During image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted, and the developing roller 39 is rotated. A developing bias is applied to the developing roller 39.

The layer thickness regulating blade 40 is provided at a plate-like support member 53 extending in the width direction, a leaf spring member 54 fixed to the support member 53 by adhesion, and a distal end portion (free end portion) of the leaf spring member 54. A pressure contact rubber 55 as an example of the contact portion is provided. In the layer thickness regulating blade 40, both end portions in the width direction of the support member 53 are fixed to the housing 36, the leaf spring member 54 extends toward the developing roller 39, and the pressure contact rubber 55 is against the rubber roller 52 of the developing roller 39. It is provided so as to be pressed from above. For this reason, the support member 53 is disposed at a position closer to the laser beam irradiated from the scanner unit 20 to the photosensitive drum 29 than the developing roller 39.
(3-2-3) Development Operation in Process Unit In each developing cartridge 27, the toner corresponding to each color stored in the toner storage chamber 43 moves to the communication port 45 while being stirred by the agitator 37, and the communication port 45 is discharged into the developing chamber 44. The toner discharged from the communication port 45 to the developing chamber 44 is supplied to the supply roller 38. The toner supplied to the supply roller 38 is supplied to the developing roller 39 by the rotation of the supply roller 38. At this time, the toner is triboelectrically charged between the supply roller 38 and the developing roller 39 to which a developing bias is applied. The toner thus supplied to the developing roller 39 enters between the pressure contact rubber 55 of the layer thickness regulating blade 40 and the rubber roller 52 of the developing roller 39 as the developing roller 39 rotates, and forms a thin layer with a constant thickness. It is carried on the surface of the rubber roller 52.

On the other hand, the surface of the photosensitive drum 29 corresponding to each developing cartridge 27 is uniformly positively charged by the scorotron charger 30 as the photosensitive drum 29 rotates. Then, as shown in FIG. 1, the surface of the positively charged photosensitive drum 29 is irradiated with a laser beam from the scanner unit 20, thereby forming an electrostatic latent image corresponding to an image to be formed on the paper 3. Is done.
When the electrostatic latent image formed on the surface of the photosensitive drum 29 is opposed to the developing roller 39 by the rotation of the photosensitive drum 29, the positively charged toner carried on the surface of the developing roller 39 becomes the electrostatic latent image ( That is, the surface of the photosensitive drum 29 that is uniformly positively charged is supplied to an exposed portion that is exposed to a laser beam and has a lowered potential. As a result, the electrostatic latent image is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 29 corresponding to each color.
(3-3) Transfer Unit The transfer unit 22 is disposed above the paper feed unit 4 and below the process unit 21 in the main body casing 2. The transfer unit 22 includes a driving roller 56, a driven roller 57, a conveyance belt 58, and a transfer roller 59.

The driving roller 56 and the driven roller 57 are disposed to face each other with a space therebetween in the front-rear direction. The conveyor belt 58 is an endless belt, and is wound between the driving roller 56 and the driven roller 57.
During image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted to the driving roller 56, and the driving roller 56 is rotated. Then, the conveying belt 58 is moved between the driving roller 56 and the driven roller 57 so as to rotate in the opposite direction to the photosensitive drum 29 at the transfer position where the conveying belt 58 faces and contacts each photosensitive drum 29 and is driven. The roller 57 is driven.

  The transfer roller 59 is provided in the conveyance belt 58 wound between the driving roller 56 and the driven roller 57 so as to face each photosensitive drum 29 with the conveyance belt 58 interposed therebetween. Each transfer roller 59 is provided so as to be driven and rotated in the same direction as the circumferential movement direction of the conveyor belt 58 at a transfer position where the transfer roller 59 faces and contacts the conveyor belt 58. At the time of image formation, a transfer bias is applied to each transfer roller 59.

The sheet 3 fed from the sheet feeding section 4 is transferred to the respective photosensitive drums 29 from the front side to the rear side by the conveyance belt 58 that is circulated by the driving roller 56 and the driven roller 57. The position is conveyed so as to pass sequentially. During the conveyance, the toner images of the respective colors carried on the respective photosensitive drums 29 are sequentially superimposed and transferred. As a result, a color image is formed on the paper 3.
(3-4) Fixing Unit The fixing unit 23 is disposed behind the transfer unit 22 and includes a heating roller 65 and a pressure roller 66 that presses the heating roller 65.

In the fixing unit 23, the color image transferred to the paper 3 is thermally fixed to the paper 3 by being heated and pressed while the paper 3 passes between the heating roller 65 and the pressure roller 66. .
(4) Paper Discharge Unit The paper discharge unit 6 includes a substantially C-shaped paper discharge path 67 that is opened forward. On the paper discharge path 67, a conveying roller 69, a pinch roller 70, and a pair of paper discharge rollers 71 are disposed. The sheet 3 conveyed from the fixing unit 23 is conveyed along a sheet discharge path 67 by a conveyance roller 69 and a pinch roller 70, and is discharged onto a sheet discharge tray 68 formed on the upper surface of the main casing 2 by the sheet discharge roller 71. The paper is ejected.
2. FIG. 3 is a perspective view of the developing cartridge 27. As shown in FIG. FIG. 4 is a view of the developing cartridge 27 with the developing roller 39 attached as viewed from below. FIG. 5 is a view of the developing cartridge 27 in a state in which the developing roller 39 is detached as viewed from below. FIG. 6 is a rear view of the developing cartridge 27 with the developing roller 39 attached. FIG. 7 is a rear view of the developing cartridge 27 with the developing roller 39 detached.
(1) Housing The housing 36 of the developing cartridge 27 is formed in a box shape as shown in FIG. 3, and has an opening 41 extending in the width direction (longitudinal direction) at the lower end thereof. .

The housing 36 includes both side walls 101 that sandwich the opening 41 in the width direction. Each side wall 101 is formed with a shaft support groove 102 that is notched upward from the lower edge. Each shaft support groove 102 receives each end of the developing roller shaft 51, whereby the developing roller 39 is rotatably supported on both side walls 101 of the housing 36.
The casing 36 is provided with a fixed wall 103 along the rear edge of the opening 41 to which the layer thickness regulating blade 40 is fixed. At both ends in the width direction of the fixed wall 103, blade fixing portions 104 to which both end portions in the width direction of the layer thickness regulating blade 40 (support member 53) are fixed are formed. Each blade fixing portion 104 has a substantially U-shape in rear view protruding downward (developing roller 39 side).

As shown in FIGS. 3 and 4, the housing 36 has a receiving member 114 for preventing the toner from dropping from the developing roller 39 below both ends in the width direction of the opening 41. Is provided.
Further, as shown in FIG. 5, the casing 36 has a leakage preventing member for preventing the toner carried on the developing roller 39 from leaking from both ends in the axial direction of the developing roller 39 to the outside of the casing 36. Side seals 116 are provided at both ends of the opening 41 in the width direction.
(2) Layer Thickness Restricting Blade FIG. 8 is a view of the layer thickness restricting blade 40 as viewed from below (developing roller 39 side), and the layer thickness restricting blade 40 is shown alone. FIG. 9 is a view of the support member 53 of the layer thickness regulating blade 40 as viewed from below. FIG. 10 is a cross-sectional view of the layer thickness regulating blade 40 taken along the cutting line AA shown in FIG.

As described above, the layer thickness regulating blade 40 includes the support member 53, the leaf spring member 54, and the pressure contact rubber 55.
(2-1) Support Member The support member 53 is made of a steel plate and extends in the width direction as viewed from the bottom (referring to viewing the layer thickness regulating blade 40 from the bottom side of the main casing 2; the same applies hereinafter) in a substantially elongated rectangular shape. Is formed. The support member 53 is formed longer in the width direction (longitudinal direction) than the distance between the blade fixing portions 104 formed on the fixing wall 103 of the housing 36. Further, as shown in FIG. 9, the support member 53 has a circular round hole 105 at the right side end portion in the width direction as viewed from the bottom surface, and slightly longer in the width direction at the left side end portion in the width direction as viewed from the bottom surface. A substantially elliptical long hole 106 is perforated.
(2-2) Leaf Spring Member The leaf spring member 54 is made of a thin metal plate and is formed to have substantially the same width as the support member 53 in the width direction. As shown in FIG. 8, the base end portion of the leaf spring member 54 facing the support member 53 has a circular round shape so that it overlaps the round hole 105 of the support member 53 at the right end when viewed from the bottom in the width direction. A hole 107 is drilled. In addition, a substantially elliptical long hole 108 that is slightly long in the width direction is perforated at the base end portion so as to overlap with the long hole 106 of the support member 53 at the left end portion in the width direction when viewed from the bottom.

Further, in the vicinity of both end portions in the width direction of the leaf spring member 54, cutout portions 119 that are cut out in a rectangular shape from the distal end edge (free end edge) of the leaf spring member 54 toward the proximal end side are formed. Yes.
(2-3) Pressing Rubber The pressing rubber 55 is provided to extend along the width direction at the tip of the leaf spring member 54 opposite to the surface facing the support member 53. The pressure contact rubber 55 is made of an elastic rubber such as insulating silicone rubber, and is formed in a substantially elongated rectangular ridge that protrudes downward in the vicinity of the developing roller 39.
(2-4) Fixing of Support Member and Leaf Spring Member The support member 53 and the leaf spring member 54 are bonded and fixed to each other by a double-sided tape 109 as shown in FIG. This double-sided tape 109 is a heat-adhesive double-sided tape in which an adhesive is applied to both sides, and the adhesive strength of the adhesive is increased by heating. As such a heat-adhesive double-sided tape, for example, one having an adhesive strength before heating of 0.6 kg or less and an adhesive strength after heating of 1.0 kg or more is used.

  The adhesive strength before and after heating is, for example, that a sheet metal made of SECC having a thickness of 1.6 ± 0.12 mm and a sheet metal made of SUS301CSP-3 / 4H having a thickness of 0.1 ± 0.015 mm are size 6. Bonding with 5 × 100 mm double-sided adhesive tape, and applying the necessary force to peel off the sheet metal in the direction orthogonal to the adhesive surface of the double-sided adhesive tape, heated and applied for 10 seconds at 130 ° C. and 0.35 MPa. It was obtained by measuring before and after pressing.

  Then, as shown in FIG. 9, the double-sided tape 109 has a front end edge (the front end portion of the leaf spring member 54 in the support member 53) on the surface of the support member 53 facing the leaf spring member 54 as shown in FIG. (End edge located on the side). The right end of the double-sided tape 109 viewed from the bottom reaches the vicinity of the round hole 105 of the support member 53, and the left end of the opposite side viewed from the bottom reaches the position in contact with the long hole 106 of the support member 53.

Further, as shown in FIG. 10, the double-sided tape 109 is attached to a surface of the leaf spring member 54 facing the support member 53 at a position spaced a predetermined width from the base edge of the leaf spring member 54 to the distal end side. Has been. Thereby, a portion having a predetermined width from the base edge of the leaf spring member 54 is opposed to the support member 53 without the double-sided tape 109 interposed therebetween.
(2-5) Fixing of Layer Thickness Restricting Blade As shown in FIG. 3, the layer thickness restricting blade 40 uses both fixing screws 110, which are right-handed screws, and fixing screws 111, which are left-handed screws. It is fixed to the fixing part 104. The fixing screw 110 is inserted into the round hole 107 (see FIG. 8) of the leaf spring member 54 and the round hole 105 (see FIG. 9) of the support member 53, and the tip part thereof is formed in one blade fixing part 104. It is screwed into a screw hole (not shown). The fixing screw 111 is inserted into the long hole 108 (see FIG. 8) of the leaf spring member 54 and the long hole 106 (see FIG. 9) of the support member 53, and the tip part thereof is formed in the other blade fixing part 104. It is screwed into a screw hole (not shown).

  The right end of the double-sided tape 109 viewed from the bottom reaches the vicinity of the round hole 105 of the support member 53. Therefore, the double-sided tape 109 and the screw head 110A of the fixing screw 110 are connected via the leaf spring member 54 with the fixing screw 110 inserted through the round hole 107 of the leaf spring member 54 and the round hole 105 of the support member 53. opposite. On the other hand, the left end of the double-sided tape 109 viewed from the bottom reaches a position in contact with the long hole 106 of the support member 53. Therefore, the double-sided tape 109 and the screw head 111A of the fixing screw 111 are connected via the leaf spring member 54 with the fixing screw 111 inserted through the elongated hole 108 of the leaf spring member 54 and the elongated hole 106 of the support member 53. opposite.

Further, since the length of the support member 53 in the width direction is longer than the interval between the blade fixing portions 104, in the state where the developing roller 39 is removed from the housing 36, as shown in FIG. The leaf spring member 54 and the pressure contact rubber 55 are bent in a gentle convex curve downward. This bending is corrected by attaching the developing roller 39 to the housing 36. That is, as shown in FIG. 6, when the developing roller 39 is held by the housing 36, the developing roller 39 comes into contact with the pressure contact rubber 55, and the pressure contact rubber 55 is pushed upward by the development roller 39, thereby supporting the support member. 53, the bending of the leaf spring member 54 and the pressure contact rubber 55 is corrected. As a result, in the layer thickness regulating blade 40, the pressure contact rubber 55 comes into contact with the developing roller 39 with a uniform pressure in the axial direction (width direction) from above by the elastic force of the leaf spring member 54.
3. As described above, the support member 53 of the layer thickness regulating blade 40 is bent toward the position where the developing roller 39 is disposed (downward) in a state where the developing roller 39 is removed from the housing 36. The blades are fixed to both blade fixing portions 104 formed on the fixing wall 103 of the housing 36. When the developing roller 39 is held by the housing 36, the pressure contact rubber 55 is pushed by the development roller 39, the bending of the support member 53 is corrected, and the pressure contact rubber 55 is in the axial direction with respect to the development roller 39. Abut with uniform pressure. Therefore, the layer thickness of the toner carried on the surface of the developing roller 39 can be regulated uniformly. As a result, it is possible to achieve a good supply of toner from the developing roller 39 to the photosensitive drum 29, and thus a good image formation can be achieved.

  In this embodiment, a blade fixing portion 104 to which each end in the longitudinal direction of the support member 53 is fixed is provided on the fixing wall 103 of the housing 36, and the length of the support member 53 in the longitudinal direction is the blade fixing portion 104. Longer than the interval between. Therefore, by fixing each longitudinal end of the support member 53 to each blade fixing portion 104, the support member 53 can be reliably bent toward the position where the developing roller 39 is disposed.

  Further, the support member 53 and the leaf spring member 54 are fixed to each other by adhesion through an adhesive layer made of a double-sided tape 109. Therefore, there is no deformation of the leaf spring member 54 (a undulation deformation that occurs when the support member 53 and the leaf spring member 54 are fixed to each other by screws), and the pressure contact rubber 55 is more uniform in the axial direction with respect to the developing roller 39. It can be contacted by pressure. Therefore, the layer thickness of the toner carried on the surface of the developing roller 39 can be regulated more uniformly.

Moreover, since the adhesive layer is composed of the double-sided tape 109, one side of the double-sided tape 109 is attached to one of the support member 53 and the leaf spring member 54, and the other of them is adhered to the other side of the double-sided tape 109. By performing an appropriate operation, the adhesive layer can be reliably disposed at a position spaced from the base edge of the leaf spring member 54 by a predetermined width.
In addition, as shown in FIG. 3, the pressure rubber 55 that contacts the developing roller 39 can be viewed from the outside of the housing 36 in a state where the developing roller 39 is held by the housing 36. Therefore, the presence or absence of toner leakage from the vicinity of both longitudinal ends of the pressure contact rubber 55 can be easily confirmed.

In recent years, recycling has been regarded as important in various fields, and in the field of image forming apparatuses, recycling of developing devices and the like is being promoted. It is also preferable to recycle the developing cartridge 27. In this case, a supplier such as a printer manufacturer collects the used developing cartridge 27 and refills the toner storage chamber 43 (see FIG. 2) with the toner to obtain a recycled product. Resupply the market. However, since the developing cartridge 27 in which a problem such as toner leakage has occurred is not suitable for recycling, a supplier such as a printer manufacturer needs to check whether or not the collected developing cartridge 27 has a problem such as toner leakage. is there. In the developing cartridge 27, the pressing rubber 55 abutting against the developing roller 39 can be visually recognized from the outside of the housing 36, and it is possible to easily check the presence or absence of toner leakage from the vicinity of both ends of the pressing rubber 55 in the longitudinal direction. Because it can, it is suitable for recycling.
4). Modification (1) First Modification FIG. 11 is a view of the main part of the developing cartridge 27 according to the first modification as viewed from below. In FIG. 11, parts corresponding to the above-described parts are denoted by the same reference numerals as those parts. In the following, detailed description of each part given the same reference numeral is omitted.

  In the developing cartridge 27, a blade seal 141, which is an elastic member for preventing toner leakage from between the layer thickness regulating blade 40 and the fixed wall 103, is disposed between the blade fixing portions 104. The blade seal 141 is made of, for example, a sponge material, and in a state where the developing roller 39 is removed from the housing 36, the developing roller 39 is disposed on the side where the developing roller 39 is disposed (below the lower surface) ).

  Thus, the support member 53 can be reliably bent toward the position where the developing roller 39 is disposed in a state where the developing roller 39 is removed from the housing 36. When the developing roller 39 is held by the housing 36, the pressure contact rubber 55 (see FIG. 3) is pressed by the developing roller 39, and the blade seal 141 is elastically deformed by the pressing force, and the support member 53 is bent. By being corrected, the pressure contact rubber 55 comes into contact with the developing roller 39 with a uniform pressure in the axial direction. Therefore, the layer thickness of the toner carried on the surface of the developing roller 39 can be regulated uniformly.

Further, since the elastic member is the blade seal 141, the support member 53 can be reliably bent toward the position where the developing roller 39 is disposed, and between the support member 53 and the fixed wall 103 of the housing 36. From the toner can be prevented.
(2) Second Modified Example FIG. 12 is a diagram for explaining a modified example of the blade fixing unit 104 (a diagram of the right side blade fixing unit 104 viewed from below). In FIG. 12, parts corresponding to the above-described parts are denoted by the same reference numerals as those parts. In the following, detailed descriptions of the respective parts having the same reference numerals except for the blade fixing part 104 are omitted.

The blade fixing portion 104 shown in FIG. 12 is formed such that the amount of protrusion downward (in the direction facing the support member 53) increases toward the inner side in the width direction, and the contact surface with the support member 53 is an inclined surface. Therefore, by fixing each end portion of the support member 53 in the longitudinal direction to each blade fixing portion 104, the support member 53 can be reliably bent toward the position where the developing roller 39 is disposed.
(3) Other Modifications In the above-described embodiment, the adhesive layer is formed by the double-sided tape 109. However, the adhesive layer is not limited to the double-sided tape 109 and is bonded to the support member 53 and / or the leaf spring member 54. You may form by apply | coating an agent.

  In the above-described embodiment, the tandem type color laser printer is exemplified as the image forming apparatus. However, the image forming apparatus is not limited to this, and for example, developer images of each color are obtained from each image carrier. It may be an intermediate transfer type color laser printer that once transfers to an intermediate transfer body and then collectively transfers to a recording medium. Moreover, not only a color laser printer but a monochrome laser printer may be used.

1 is a side sectional view showing an embodiment of a color laser printer as an example of an image forming apparatus of the present invention. FIG. 4 is a side sectional view of the developing cartridge. FIG. 3 is a perspective view of a developing cartridge. FIG. 4 is a view of the developing cartridge with the developing roller attached as viewed from below. FIG. 6 is a view of the developing cartridge in a state where the developing roller is detached from the lower side. FIG. 6 is a rear view of the developing cartridge with a developing roller attached thereto. FIG. 6 is a rear view of the developing cartridge in a state where the developing roller is detached. It is the figure which looked at the layer thickness control blade from the lower part (developing roller side), and the layer thickness control blade is shown alone. It is the figure which looked at the supporting member of the layer thickness control blade from the lower part. It is sectional drawing when a layer thickness control blade is cut | disconnected by the cutting line AA shown in FIG. FIG. 4 is a view of a main part of a developing cartridge provided with a blade seal as viewed from below. It is a figure for demonstrating the modification of a blade fixing | fixed part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color laser printer 27 Developing cartridge 29 Photosensitive drum 36 Case 39 Developing roller 40 Layer thickness control blade 53 Support member 54 Leaf spring member 55 Pressure contact rubber 103 Fixed wall 104 Blade fixing part 109 Double-sided tape 141 Blade seal

Claims (9)

A developing device comprising a casing, a developing roller held in the casing and carrying a developer, and a layer thickness regulating blade for regulating the layer thickness of the developer carried on the developing roller,
The layer thickness regulating blade is
A support member formed in a longitudinal shape extending in the axial direction of the developing roller and attached to the housing;
A leaf spring member extending from the support member toward the developing roller;
Provided at the tip of the leaf spring member, and a contact portion that contacts the developing roller,
In a state where the developing roller is held in the casing, the contact portion is in contact with a uniform pressure in the axial direction of the developing roller, and in a state where the developing roller is removed from the casing, the layer thickness The developing device, wherein the support member is attached to the housing so that the regulating blade bends toward a position where the developing roller is disposed. A blade fixing portion provided in the casing so as to be opposed to each end portion in the longitudinal direction of the support member, and to which each end portion in the longitudinal direction of the support member facing the blade is fixed;
The blade fixing portion is disposed between each of the blade fixing portions, interposed between the housing and the support member, and the developing roller is removed from the housing, with the support member of the blade fixing portion. The developing device according to claim 1, further comprising: an elastic member that protrudes toward a position where the developing roller is disposed from a facing surface.   The developing device according to claim 2, wherein the elastic member is a blade seal that seals between the housing and the support member.   The casing is provided to face each end portion of the support member in the longitudinal direction, and the protruding amount in the facing direction to the support member is formed larger toward the inner side in the longitudinal direction. The developing device according to claim 1, further comprising a blade fixing portion to which the portion is fixed. Provided with a blade fixing portion provided in the casing so as to face each end portion in the longitudinal direction of the support member, and to fix each end portion in the longitudinal direction of the support member facing the housing;
The developing device according to claim 1, wherein a length of the support member in a longitudinal direction is longer than a distance between the blade fixing portions.   6. The adhesive member according to claim 1, further comprising an adhesive layer interposed between the support member and the leaf spring member and fixing the support member and the leaf spring member by adhesion. The developing device according to any one of the above.   The developing device according to claim 6, wherein the adhesive layer is a double-sided tape with adhesive applied on both sides.   8. The developing device according to claim 6, wherein the contact portion is visible from the outside of the housing in a state where the developing roller is held by the housing. 9. A developing device according to any one of claims 1 to 8,
An image forming apparatus comprising: an image carrier to which a developer is supplied from the developing roller.

Images