JP2011133768A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of suppressing local unevenness of layer thickness of developer regulated on an outer peripheral surface of a developer carrier by a layer thickness regulating member. <P>SOLUTION: A developing cartridge 16 includes a side seal 122 coming into contact with both ends in a width direction of the outer peripheral surface of a developing roller 22, and the layer thickness regulating member 24. The layer thickness regulating member 24 includes a blade 100 regulating the layer thickness of toner on the outer peripheral surface of the developing roller 22 by coming into contact with the outer peripheral surface of the developing roller 22, and a supporting member 101 supporting the blade 100. The layer thickness regulating member 24 has a pair of first ranges A located at both ends in the width direction and held by the developing roller 22 and the side seal 122, and a second range B provided between the pair of first ranges A. The blade 100 and the supporting member 101 are not welded in the first ranges A, but is welded over in the width direction in the second range B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

As a developing device, a developing cartridge that is equipped in an image forming apparatus and develops an electrostatic latent image on a photosensitive drum is known (for example, see Patent Document 1).
In the developing cartridge described in Patent Document 1, toner is accommodated inside the casing, and a developing roller for carrying the accommodated toner is accommodated in a rotatable state. At the time of image formation, the developing roller is in contact with the photosensitive drum over the entire region in the rotation axis direction, and supplies toner to the electrostatic latent image on the photosensitive drum by rotating. Thereby, the electrostatic latent image on the photosensitive drum can be developed.

Here, the developing cartridge is provided with a layer thickness regulating member. The layer thickness regulating member includes an elastic blade that contacts the outer circumferential surface of the developing roller and regulates the thickness (layer thickness) of the toner on the outer circumferential surface of the developing roller, and a support member that supports the elastic blade. . The elastic blade and the support member are welded.
Further, a seal member is provided on the housing of the developing cartridge. The seal member prevents the toner from leaking from both ends of the outer peripheral surface of the developing roller by contacting both ends of the outer peripheral surface of the developing roller in the rotation axis direction of the developing roller.

JP 2006-145932 A

In the developing cartridge described in Patent Document 1, in order to prevent toner leakage from both end portions of the layer thickness regulating member in the rotation axis direction of the developing roller, the seal member is not only the both end portions of the outer peripheral surface of the developing roller but also the layer. It is desirable that both ends of the thickness regulating member are also in contact.
However, in that case, both end portions of the layer thickness regulating member are pressed against the outer peripheral surface of the developing roller by the seal member. As a result, the contact pressure of the elastic blade against the outer peripheral surface of the developing roller is locally increased at both ends in the rotation axis direction of the developing roller. For this reason, the toner layer thickness on the outer peripheral surface of the developing roller becomes thin at the end in the rotation axis direction of the developing roller, and as a result, the image quality may be deteriorated.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device capable of suppressing local non-uniformity of the developer layer thickness regulated on the outer peripheral surface of the developer carrying member by the layer thickness regulating member.

  In order to achieve the above object, the present invention provides a developing device, comprising: a housing; a developer carrier that is rotatably supported by the housing and carries a developer on an outer peripheral surface; and the housing. A leakage preventing member that contacts both ends of the outer peripheral surface of the developer carrying member in the rotation axis direction of the developer carrying member and prevents the developer from leaking at both ends; and the developer carrying member Layer thickness regulation including a blade that regulates the layer thickness of the developer on the outer circumferential surface of the developer carrier by contacting the outer circumferential surface of the developer along the rotational axis direction, and a support member that supports the blade A layer thickness regulating member sandwiched between the outer peripheral surface of the developer carrier and the leakage preventing member at both ends in the rotation axis direction, the layer thickness regulating member in the rotation axis direction The developer located at both ends A pair of first ranges sandwiched between the holding body and the leakage prevention member, and a second range provided between the pair of the first ranges, the blade and the support member, It is characterized by not being welded in the first range but being welded in the direction of the rotation axis in the second range.

According to this invention, in the developing device, the developer carrying member carrying the developer on the outer peripheral surface is rotatably supported by the housing. The developing device includes a leakage prevention member and a layer thickness regulating member.
The leakage preventing member is provided on the housing. The leakage prevention member contacts both ends of the outer peripheral surface of the developer carrier in the rotation axis direction of the developer carrier (hereinafter simply referred to as “rotation axis direction”), and leaks the developer at both ends. To prevent.

The layer thickness regulating member supports a blade that regulates the layer thickness of the developer on the outer circumferential surface of the developer carrying member by contacting the outer circumferential surface of the developer carrying member along the rotation axis direction. And a support member.
Here, the layer thickness regulating member is sandwiched between the outer peripheral surface of the developer carrier and the leakage preventing member at both ends in the rotation axis direction. Specifically, the layer thickness regulating members are located at both ends in the rotation axis direction and are provided between a pair of first ranges and a pair of first ranges sandwiched between the developer carrier and the leakage preventing member. Two ranges.

In such a layer thickness regulating member, the blade and the support member are not welded in the first range, but are welded in the rotation range in the second range.
Therefore, in the first range that is sandwiched between the developer carrier and the leakage prevention member (in other words, pressed against the developer carrier by the leakage prevention member), the blade disperses the pressing force from the leakage prevention member. And the influence of pressing of the leakage preventing member can be reduced. Thereby, the contact pressure of the blade with respect to the outer peripheral surface of the developer carrying member does not increase locally in the first range, but becomes uniform in the entire rotation axis direction. Thereby, the local nonuniformity of the layer thickness of the developer regulated on the outer peripheral surface of the developer carrier by the layer thickness regulating member can be suppressed.

1 is a right side sectional view of a printer according to the present invention. It is a right side sectional view of a process cartridge. FIG. 4 is a right side sectional view of the developing cartridge. FIG. 3 is a perspective view of the developing cartridge as viewed from the upper left front side. It is the perspective view which looked at the development frame from the front upper right side. It is the perspective view which looked at the layer thickness control member from the front left upper side. It is a disassembled perspective view of a layer thickness control member. (A) is a front view of the developing cartridge, and (b) shows a state in which the developing roller is omitted in (a). It is AA arrow sectional drawing of Fig.8 (a).

1. Overall Configuration of Printer As shown in FIG. 1, a printer 1 as an example of an image forming apparatus includes a paper feed unit 3 for feeding a paper S as an example of a recording medium in a main body casing 2, and a paper feed And an image forming unit 4 for forming an image on the sheet S.
The main body casing 2 is formed in a box shape having a substantially rectangular shape in side view that accommodates the paper feeding unit 3 and the image forming unit 4, and a cover 5 for attaching and detaching a process cartridge 13 described later is provided on one side wall thereof. Is formed. The cover 5 is provided to be swingable with respect to the main body casing 2 with the lower end portion as a fulcrum. When the cover 5 is opened, the process cartridge 13 can be attached to and detached from the main body casing 2.

In the following description, the side on which the cover 5 is provided (the right side in FIG. 1) is the rear side, and the opposite side (the left side in FIG. 1) is the front side. In addition, when the printer 1 is viewed from the front side, the left and right reference is used. That is, the back side of the paper surface of FIG. 1 is the left side, and the front side of the paper surface is the right side. The left-right direction is sometimes referred to as the width direction.
The paper feeding unit 3 is provided in the lower part of the main casing 2. The paper feed unit 3 includes a paper feed tray 6 that accommodates the paper S, a pickup roller 7 provided above the rear end of the paper feed tray 6, and a separation roller 8 that is disposed opposite to the rear side of the pickup roller 7. And a separation pad 9. The paper feed unit 3 includes a pair of front and rear paper feed rollers 10 disposed opposite to each other above the separation pad 9, a paper feed path 11 extending substantially frontward from the opposed portion of both paper feed rollers 10, and paper feed And a main body side registration roller 20 disposed in front of the path 11.

  Sheets S are stacked in the sheet feed tray 6, and the uppermost sheet S is supplied to a portion where the separation roller 8 and the separation pad 9 are opposed by the rotation of the pickup roller 7 as indicated by a broken line. And they will be beaten one by one. Thereafter, the sheet S passes through the sheet feeding path 11 by the conveyance of both sheet feeding rollers 10 and is conveyed between the main body side registration roller 20 and the process side registration roller 21 (described later), and at a predetermined timing. It is conveyed between a photosensitive drum 17 (described later) as an example of a body and a transfer roller 19 (described later).

In addition to the paper feeding unit 3 described above, the paper S is returned from the paper discharge path 27 (described later) to a position between the main body side registration roller 20 and the process side registration roller 21 (described later) (see the alternate long and short dash line). A mechanism is provided, and the printer 1 can perform duplex printing.
The image forming unit 4 includes an exposure unit 12, a process cartridge 13, and a fixing unit 14.

The exposure unit 12 is disposed on the upper part of the main casing 2. The exposure unit 12 irradiates the photosensitive drum 17 (described later) by irradiating light (laser beam indicated by a dashed arrow) toward the photosensitive drum 17 (described later) based on the image data.
The process cartridge 13 is detachably accommodated in the main body casing 2 below the exposure unit 12 and above the paper feed unit 3, and is an example of a drum cartridge 15 and a developing device that is detachably attached to the drum cartridge 15. As a developing cartridge 16.

The drum cartridge 15 includes a photosensitive drum 17, a scorotron charger 18 and a transfer roller 19.
The photosensitive drum 17 is long in the width direction, and is provided at the front end of the drum cartridge 15 so as to be rotatable along the left-right direction. The charger 18 is disposed on the front upper side of the photosensitive drum 17 so as to face the photosensitive drum 17 with a gap. The transfer roller 19 is disposed to face the lower side of the photosensitive drum 17 and is pressed against the photosensitive drum 17 from the lower side.

The drum cartridge 15 includes a process-side registration roller 21.
The process side registration roller 21 is provided so as to be in contact with the main body side registration roller 20 from the upper side at the lower end of the drum cartridge 15 at the substantially center in the front-rear direction.
The developing cartridge 16 includes a developing roller 22 that is long in the width direction as an example of a developer carrier.

The developing roller 22 is rotatably supported at the front end portion of the developing cartridge 16 so as to be exposed from the front side, and is pressed toward the photosensitive drum 17 from the rear side.
Further, the developing cartridge 16 supplies a toner as an example of a developer to the developing roller 22 and has a supply roller 23 that is long in the width direction, and a layer thickness that regulates the thickness (layer thickness) of the toner supplied to the developing roller 22. The regulating member 24 is provided, and toner is accommodated in a space behind them.

At the time of image formation, the toner in the developing cartridge 16 is supplied to the supply roller 23 and further supplied to the developing roller 22, and is triboelectrically charged between the supply roller 23 and the developing roller 22.
The toner supplied to the developing roller 22 is regulated in thickness by the layer thickness regulating member 24 as the developing roller 22 rotates, and is carried on the surface (outer peripheral surface) of the developing roller 22 as a thin layer having a constant thickness. The

On the other hand, the surface (outer peripheral surface) of the photosensitive drum 17 is uniformly positively charged by the charger 18 as the photosensitive drum 17 rotates, and then the laser beam from the exposure unit 12 (see the broken line arrow) is scanned at high speed. Is exposed. As a result, an electrostatic latent image corresponding to the image to be formed on the paper S is formed on the surface of the photosensitive drum 17.
When the photosensitive drum 17 further rotates, the toner that is carried on the surface of the developing roller 22 and is positively charged is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 17. As a result, the electrostatic latent image on the photosensitive drum 17 is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 17.

The sheet S conveyed between the photosensitive drum 17 and the transfer roller 19 is carried by the photosensitive drum 17 when passing between the photosensitive drum 17 and the transfer roller 19 as indicated by a broken line. The toner image is transferred onto the paper S.
The fixing unit 14 is disposed in front of the process cartridge 13 and includes a heating roller 25 and a pressure roller 26 facing the heating roller 25. In the process cartridge 13, the toner image transferred onto the paper S is heat-fixed on the paper S by being heated and pressed while the paper S passes between the heating roller 25 and the pressure roller 26. .

The paper S on which the toner image is fixed passes through a paper discharge path 27 formed of a U-turn path and is conveyed toward the paper discharge roller 28 as shown by a broken line. The paper is discharged onto a paper discharge tray 29 provided.
2. Details of Process Cartridge (1) Drum Cartridge As shown in FIG. 2, the drum cartridge 15 has a substantially rectangular shape that is flattened up and down when viewed from the width direction. The drum cartridge 15 includes a drum frame 30 that forms an outline thereof.

The drum frame 30 has a hollow box shape that is flat up and down. In the drum frame 30, an attachment / detachment port 31 is formed in the top wall 30 </ b> A, an inlet 32 is formed in the bottom wall 30 </ b> B, and an outlet 33 is formed in the front wall 30 </ b> C. 32 and the outlet 33 are communicated to the outside.
The attachment / detachment port 31 is formed in a region forming approximately three-fourths of the rear side of the ceiling wall 30A. The inlet 32 is formed at a front position on the bottom wall 30B. The entrance 32 and the exit 33 are wider than the sheet S (see FIG. 1).

On the bottom wall 30B, behind the inlet 32, the above-described process-side registration roller 21 is rotatably disposed so as to face downward.
The interior of the drum frame 30 is divided into a front-side drum housing chamber 34 and a rear-side cartridge housing chamber 35. The drum storage chamber 34 and the cartridge storage chamber 35 communicate with each other.

The drum accommodating chamber 34 accommodates the photosensitive drum 17, the charger 18, and the transfer roller 19 described above. The charger 18 is supported on the upper end of the front wall 30C. The rear outer peripheral surface of the photosensitive drum 17 faces the cartridge storage chamber 35 from the front side.
The above-described attachment / detachment port 31 communicates directly with the cartridge storage chamber 35 from above. A pair of pressing members 36 are provided at the rear end portion inside the cartridge housing chamber 35 with a gap in the width direction. Each pressing member 36 has a thin plate shape in the width direction and narrows upward as viewed from the width direction. Each pressing member 36 is supported by the drum frame 30 (the left and right side walls or the rear wall of the drum frame 30). In this state, the pressing member 36 can rotate around a rotation shaft (not shown) extending in the width direction. is there. Each pressing member 36 is urged by an urging member (spring or the like) (not shown) so as to rotate counterclockwise when viewed from the width direction.

  When the developing cartridge 16 is accommodated in the cartridge accommodating chamber 35 from the attachment / detachment port 31 of the drum frame 30, the mounting of the developing cartridge 16 to the drum cartridge 15 is completed. On the other hand, the developing cartridge 16 can be detached from the drum cartridge 15 by taking out the developing cartridge 16 accommodated in the cartridge accommodating chamber 35 from the attachment / detachment port 31.

Further, the sheet S conveyed from the sheet feed tray 6 passes through the inlet 32 and travels between the photosensitive drum 17 and the transfer roller 19 as described above (see FIG. 1). On the other hand, the sheet S on which the toner image is transferred as described above goes to the fixing unit 14 through the outlet 33 (see FIG. 1).
(2) Developing Cartridge With reference to FIGS. 3 and 4, the developing cartridge 16 has a box shape that is long in the width direction and flat in the vertical direction. Referring to FIG. 3, the developing cartridge 16 mainly includes a developing frame 40 as an example of a casing that forms the outer shell, the developing roller 22, the supply roller 23, the layer thickness regulating member 24, and an agitator 41. I have.
(2-1) Development Frame The development frame 40 is made of resin and has a box shape that is long in the width direction and flat in the vertical direction. The development frame 40 includes a pair of side walls 42, a top wall 43, a bottom wall 44, and a rear wall 45 that are opposed to each other with a gap in the width direction.

  Each side wall 42 has a substantially rectangular shape that is long in the front-rear direction when viewed from the width direction and is thin in the width direction. Referring to FIG. 5, in each side wall 42, the front end portion is thinner in the width direction than the portion on the rear side from the front end portion (see the left side wall 42 </ b> L). Accordingly, a stepped portion 48 is formed at the boundary between the front end portion and the rear portion of the front end portion on the inner side surface in the width direction of each side wall 42 (the surface facing the inner space of the developing frame 40).

The stepped portion 48 has a pasting surface 49 that faces the front side while curving so as to form a substantially J shape when viewed from the right side.
The stepped portion 48 has a screwed portion 50 at a position adjacent to the pasting surface 49 from above. The screwing portion 50 has a substantially block shape, and its front end surface is flat along a substantially vertical direction, and is located at a position shifted from the upper end portion of the sticking surface 49 to the front side. A cylindrical boss 51 that protrudes slightly to the front side is integrally provided at a position above the front end surface of the screwing portion 50. A screw hole 52 extending rearward toward the inside of the screwed portion 50 is formed at the center of the circle of the front end surface of the boss 51.

A dent 53 that is long in the vertical direction and recessed toward the rear side is formed at the outer end in the width direction of the front end surface of the screwed portion 50 (a position on the outer side in the width direction from the boss 51).
Each side wall 42 is formed with a receiving groove 39 that cuts out the front end portion from the front end edge toward the rear side. Referring to the right side wall 42R, the receiving groove 39 has a substantially circular shape when viewed from the width direction, and penetrates the side wall 42 in the width direction. On the other hand, the receiving groove 39 of the left side wall 42L has a substantially circular shape similar to the receiving groove 39 of the right side wall 42R, and extends further to the rear side continuously from this part, and cuts the pasting surface 49 up and down. Part to be included.

A pressing boss 38 that protrudes outward in the width direction is integrally provided at the rear end portion of the side surface 42 in the width direction.
The top wall 43 has a thin plate shape extending vertically between the upper end edges of the pair of side walls 42. The top wall 43 integrally includes a front first ceiling wall 61 that has a substantially rectangular shape elongated in the width direction, and a rear second ceiling wall 62 that has a substantially rectangular shape wider than the first ceiling wall 61. In plan view, it has a substantially convex shape that is long in the width direction and narrows toward the front side.

In the first ceiling wall 61, both end portions in the width direction form inclined walls 63 inclined toward the front lower side (rear upper side), but the portion sandwiched between these inclined walls 63 is flat along the substantially horizontal direction. It is.
The front end surface of the first top wall 61 is flat along a substantially vertical direction and serves as a facing surface 66. The facing surface 66 has a substantially rectangular shape elongated in the width direction when viewed from the front.
In such a ceiling wall 43, the first ceiling wall 61 is constructed between the upper end edges of the left and right side walls 42 (specifically, between the lower end portions of the left and right screwing portions 50), and the second ceiling wall 62. However, it is constructed between the upper end edges of the left and right side walls 42 (specifically, between the rear side portions of the upper end edges of the left and right side walls 42 from the screwed portion 50).

Further, the facing surface 66 of the top wall 43 is disposed between the lower end portions of the left and right screwing portions 50 at a position slightly shifted rearward from the front end surfaces of the left and right screwing portions 50. Further, the top surface of the developing frame 40 has a recess 88 that is partitioned downwardly by a first ceiling wall 61 and a left and right screwed portion 50 that are installed between the lower ends of the left and right screwed portions 50. Is formed.
The bottom wall 44 has a thin plate shape extending vertically between the lower end edges of the pair of side walls 42, and has a substantially rectangular shape that is long in the width direction in plan view.

The bottom wall 44 is integrally provided with a first bottom wall 69, a second bottom wall 70, and a third bottom wall 71 in this order from the front side. The third bottom wall 71 forms approximately two-thirds of the rear side of the bottom wall 44 (see FIG. 3).
The first bottom wall 69 extends to the front lower side (see also FIG. 3), and is spanned between the front side portions of the sticking surfaces 49 of the left and right side walls 42. The second bottom wall 70 continuously extends from the rear end edge of the first bottom wall 69 to the rear side, and bulges downward in an arc shape when viewed from the width direction (see also FIG. 3). The third bottom wall 71 continuously extends from the rear end edge of the second bottom wall 70 to the rear side, and bulges downward in an arc shape when viewed from the width direction (see also FIG. 3).

Here, the front end of the top wall 43 described above is shifted rearward from the front ends of the left and right side walls 42 and the bottom wall 44 by the amount of the first bottom wall 69.
The rear wall 45 (see FIG. 3) has a thin plate shape in the front-rear direction, and has a substantially rectangular shape that is long in the width direction when viewed from the front. The rear wall 45 is constructed between the rear end edges of the pair of side walls 42 so as to connect the pair of side walls 42, while the rear end edge of the top wall 43 (second top wall 62) and the bottom wall 44 ( It is constructed between the rear end edge of the third bottom wall 71) (see FIG. 3). An extending portion 73 extending rearward is integrally provided at the upper end edge of the rear wall 45. The extending portion 73 has a plate shape that is long in the width direction in plan view. A handle 74 that protrudes rearward and upward is integrally provided at the center in the width direction of the rear end portion of the extended portion 73.

An opening 75 elongated in the width direction is formed on the front surface of the developing frame 40. The opening 75 is defined by front end portions of the left and right side walls 42, the top wall 43 and the bottom wall 44, and communicates with the internal space of the developing frame 40.
Referring to FIG. 3, the internal space sandwiched between the pair of left and right side walls 42 in the developing frame 40 is partitioned into a developing roller storage chamber 76, a developing chamber 77, and a toner storage chamber 78. The developing roller storage chamber 76, the developing chamber 77, and the toner storage chamber 78 are arranged in this order from the front side, and those adjacent to each other in the front-rear direction communicate with each other. The lower end of the developing roller storage chamber 76 is partitioned by a first bottom wall 69, the lower end of the developing chamber 77 is partitioned by a second bottom wall 70, and the lower end of the toner storage chamber 78 is a third bottom wall. 71. Toner is stored in the toner storage chamber 78. Further, the left and right screwed portions 50 are located at the same position as the developing chamber 77 in the front-rear direction.
(2-2) Developing Roller, Supply Roller, and Agitator The developing roller 22 is accommodated in the developing roller accommodating chamber 76, the supplying roller 23 is accommodated in the developing chamber 77, and the agitator 41 is accommodated in the toner accommodating chamber 78. Yes.

  The developing roller 22 includes a cylindrical roller shaft 22A extending in the width direction, and a cylindrical rubber roller 22B covering the roller shaft 22A except for both ends in the width direction. Both end portions in the width direction of the roller shaft 22A are fitted from the front side to the receiving grooves 39 (see FIG. 5) of the side wall 42 on the same side in the width direction in the developing frame 40 via bearings 79 (see FIG. 4). ing. In this state, both ends in the width direction of the developing roller 22 are rotatably supported by the left and right side walls 42 via bearings 79 at both ends in the width direction of the roller shaft 22A (see FIG. 4). That is, the developing roller 22 can rotate around a rotation shaft (roller shaft 22A) extending in the width direction, and the rotation shaft direction of the developing roller 22 is the width direction.

  In this state, a lower film 80 is attached to the upper surface of the first bottom wall 69 (the surface facing the lower outer peripheral surface of the developing roller 22 from below). The lower film 80 is formed of a flexible material such as a PET sheet or a rubber sheet, and has a substantially rectangular shape that is elongated in the width direction, and extends rearward and upward as viewed from the width direction. The rear upper end of the lower film 80 is in contact with the lower outer peripheral surface of the rubber roller 22 </ b> B of the developing roller 22 over the entire width direction, whereby the developing roller 22 and the first bottom wall 69 are in contact with each other. The gap is blocked.

  Further, side seals as an example of a leakage prevention member formed in a belt shape with an elastic member such as felt or sponge on the inner side in the width direction of the left and right side walls 42 of the developing frame 40 (see FIG. 5). 122 (see FIG. 8B and FIG. 9) is attached. The side seals 122 attached to the pair of left and right attachment surfaces 49 are in contact with both ends in the width direction of the rear outer peripheral surface of the developing roller 22 (rubber roller 22B) from the rear side and are on the same side in the width direction. The gap between the sticking surface 49 and the outer peripheral surface of the end portion in the width direction of the rubber roller 22B is closed without any gap (see FIG. 9).

Both ends of the supply roller 23 in the width direction are rotatably supported by the left and right side walls 42.
The agitator 41 is rotatable about a rotation shaft 41A that is provided between the left and right side walls 42 and extends in the width direction.
Here, in the right side view, the developing roller 22 and the supply roller 23 rotate counterclockwise, and the agitator 41 rotates clockwise.
(2-3) Layer Thickness Restricting Member Referring to FIG. 6, the layer thickness regulating member 24 includes a blade 100 that actually regulates the thickness of the toner supplied to the developing roller 22 (see FIG. 3), and the blade 100. The supporting member 101 to support is included.

  Referring to FIG. 7, the blade 100 has a thin plate shape in the front-rear direction, and has a substantially rectangular shape elongated in the width direction when viewed from the front. The blade 100 is made of a metal having elasticity. The width direction dimension of the blade 100 is substantially the same as the width direction dimension of the rubber roller 22B (see FIG. 4) of the developing roller 22. In the blade 100, the upper end portion is slightly wider than the portion below the upper end portion.

  At both end portions in the width direction of the upper end portion of the blade 100, through holes 103 that penetrate the blade 100 in the thickness direction (front-rear direction) are formed. The left through hole 103L is a long hole extending in the width direction, and the right through hole 103R is a round hole. The lower end portion of the blade 100 is curved in an arc shape toward the rear end toward the lower end edge over the entire width direction, and serves as a pressing portion 104 (see also FIG. 3).

The support member 101 is formed by bending an elongated metal plate in the width direction into an L shape when projected from the width direction. The metal plate constituting the support member 101 is made of a highly rigid (hard to bend) metal, and the thickness thereof is thicker than the thickness of the blade 100. Therefore, the support member 101 is very strong.
The support member 101 is bent at a substantially right angle around the bent portion 101A, and a first support portion 105 as an example of a welded portion located on one side (lower side in FIG. 7) with respect to the bent portion 101A, It integrally includes a second support portion 106 as an example of an extending portion located on the other side (the rear side in FIG. 7) with respect to the bent portion 101A.

The first support portion 105 has a substantially rectangular plate shape that is thin in the front and rear direction and elongated in the width direction when viewed from the front, and the width direction dimension thereof is substantially the same as the width direction dimension of the blade 100. The front and back side surfaces of the first support portion 105 are flat along a substantially vertical direction. At both ends in the width direction of the front side surface of the first support portion 105, columnar convex portions 109 projecting to the front side are integrally provided.
Protruding portions 108 that protrude upward from the upper end edge of the first support portion 105 are integrally provided at both ends in the width direction of the first support portion 105. Each protrusion 108 has a front and rear thin plate shape having the same thickness as the first support part 105, and in each protrusion 108, the front side is flush with the front side of the first support 105. These are flush with the rear side surface of the first support part 105. Therefore, when projected from the width direction, the left and right protruding portions 108 and the first support portion 105 are arranged on the same plane extending in the vertical direction. The left and right protrusions 108 are part of the first support part 105.

Each protrusion 108 is substantially rectangular in a front view. Each protrusion 108 is formed with a mounting hole 110 that penetrates the protrusion 108 in the thickness direction (front-rear direction). The attachment hole 110L of the left protrusion 108L is a long hole that is slightly longer in the width direction, and the attachment hole 110R of the right protrusion 108R is a round hole.
The second support part 106 is a substantially rectangular plate shape that is vertically thin and elongated in the width direction in plan view, and its width direction dimension is slightly smaller than the interval between the left and right protrusions 108. The upper and lower side surfaces of the second support portion 106 are flat along a substantially horizontal direction. That is, the 2nd support part 106 is extended along the substantially horizontal direction.

When assembling the layer thickness regulating member 24 having the blade 100 and the support member 101, first, the blade 100 and the support member 101 are brought into the posture shown in FIG.
Then, the blade 100 is attached to the support member 101 from the front. At the time of attachment, first, the right convex portion 109R of the support member 101 is inserted from the rear side into the right through hole 103R of the blade 100 so that the right portion of the blade 100 is the right portion of the first support portion 105 of the support member 101. Position to. Thereafter, the blade 100 is tilted rearward with the through hole 103R side as a fulcrum.

  Then, the left convex portion 109L of the support member 101 is inserted from the rear side into the left through hole 103L of the blade 100, and the left portion of the blade 100 is positioned at the left portion of the first support portion 105. . As a result, as shown in FIG. 6, the blade 100 is positioned with respect to the first support portion 105 of the support member 101, and the substantially upper half of the rear side surface of the blade 100 is relative to the front side surface of the first support portion 105. Surface contact is made over almost the entire region in the width direction.

  Here, since the left through hole 103L is a long hole, even if there is an error in the interval between the convex portion 109R and the convex portion 109L, the left convex portion 109L is reliably inserted into the left through hole 103L. . Further, the front end portion of each convex portion 109 inserted through the corresponding through hole 103 protrudes from the front side surface of the blade 100 to the front side in the thickness direction (front-rear direction) of the blade 100 (see also FIG. 9).

In this state, the blade 100 is attached to the first support portion 105 of the support member 101 by welding.
Specifically, at a plurality of welding positions 121 spaced at substantially equal intervals in the width direction, the upper end portion (the portion between the left and right through holes 103) of the blade 100 and the first support portion 105 are welded by spot welding or the like. Is done. Thereby, the blade 100 and the support member 101 are integrated, and the assembly of the layer thickness regulating member 24 is completed. Here, the range in which the welding position 121 is provided in the width direction will be described later.

Thus, in the state where the assembly of the layer thickness regulating member 24 is completed, the substantially lower half of the blade 100 protrudes downward from the first support portion 105 (see FIG. 3).
Next, attachment of the layer thickness regulating member 24 to the developing frame 40 (see FIG. 5) will be described. At this time, the developing roller 22 is not attached to the developing frame 40.
First, prior to the attachment of the layer thickness regulating member 24, the seal member 119 is attached to the facing surface 66 (see FIG. 5) of the developing frame 40 from the front side (see FIG. 3). The seal member 119 has a band shape elongated in the width direction formed of sponge or the like, and has substantially the same size as the facing surface 66 in a front view.

Next, the layer thickness regulating member 24 is disposed above the front end portion of the first top wall 61 (see FIG. 5) of the developing frame 40, and the layer thickness regulating member 24 is lowered. Then, in the layer thickness regulating member 24, the second support portion 106 is fitted from above into the recess 88 (see FIG. 5) between the left and right screwed portions 50 in the developing frame 40, and is attached to the first ceiling wall 61. Opposite from above.
At this time, in the support member 101 of the layer thickness regulating member 24, the left and right protruding portions 108 face the front end surface of the screwed portion 50 (see FIG. 5) at the same position in the width direction in the developing frame 40 from the front side. At the same time, the mounting hole 110 of the protruding portion 108 faces the boss 51 and the screw hole 52 (see FIG. 5) of the corresponding screwed portion 50 from the front side. Further, the first support portion 105 of the support member 101 and the substantially lower half of the blade 100 face the seal member 119 (in other words, the facing surface 66 to which the seal member 119 is attached) from the front side (see FIG. 3).

Next, in this state, the entire layer thickness regulating member 24 is translated backward.
Then, the first support portion 105 and the substantially lower half of the blade 100 press the seal member 119 against the rear facing surface 66, so that the seal member 119 includes the substantially lower half of the blade 100 and the first support portion 105, It compresses between the opposing surfaces 66 (refer FIG. 3). Further, the bosses 51 (see FIG. 5) of the corresponding screwing portions 50 are fitted into the mounting holes 110 of the left and right protruding portions 108 from the rear side, and the bosses 51 and the screw holes 52 (see FIG. 5) are the mounting holes 110. Exposed to the front side.

  Further, at this time, the depression 53 at the outer end in the width direction on the front end surface (surface facing the layer thickness regulating member 24 in the developing frame 40) of each screwed portion 50 facing either of the left and right protruding portions 108, The width direction outer edge of the corresponding protrusion 108 coincides with the front view (see FIG. 4). Therefore, even if there is a flash on the outer edge in the width direction of the protrusion 108, the flash fits in the recess 53.

Finally, when the screws 120 (see FIG. 3) are assembled from the front side into the screw holes 52 (see FIG. 5) of the bosses 51 of the left and right screwing portions 50, the left and right protrusions 108 are shown in FIG. Is sandwiched from the front and back by the head of the screw 120 and the screwing portion 50. Accordingly, the layer thickness regulating member 24 is attached to the developing frame 40 only at the left and right protruding portions 108.
In this embodiment, the layer thickness regulating member 24 is once lowered and then moved to the rear side to be attached to the developing frame 40. However, the layer thickness regulating member 24 is first moved to the rear side and then lowered. It may be attached to the developing frame 40 by making it, or the layer thickness regulating member 24 may be attached to the developing frame 40 by moving the layer thickness regulating member 24 obliquely linearly downward to the lower back.

Here, since the screw 120 is above the blade 100 and is not in contact with the blade 100, the blade 100 bends (wags) when the force for assembling the screw 120 to the screwing portion 50 acts on the blade 100. There is nothing.
At this time, since the left and right protrusions 108 are attached to the screwing portions 50 on the same side in the width direction, the support member 101 integrally including the left and right protrusions 108 has the left and right screwing portions 50, That is, it is constructed between the left and right side walls 42. Here, as described above, since the left and right screwed portions 50 are in the same position as the developing chamber 77 (see FIG. 3) in the front-rear direction, the support member 101 is located between the pair of left and right side walls 42 in the developing chamber 77. It is built in.

  At this time, in the layer thickness regulating member 24, the blade 100 is along the width direction and the vertical direction. Further, the second support portion 106 is located at the deepest portion of the concave portion 88 on the top surface of the developing frame 40 and is adjacent to the first top wall 61 from above with a predetermined gap (FIG. 3). reference). Moreover, the 1st support part 105 (except the protrusion parts 108 on either side) has opposed the front-end surface (opposing surface 66) of the 1st ceiling wall 61 from the front on both sides of the sealing member 119 (refer FIG. 3). .

  Further, in the state where the layer thickness regulating member 24 is attached to the developing frame 40, the left and right side seals 122 described above are located at the lower end of the layer thickness regulating member 24 in a front view as shown in FIG. It overlaps with both ends in the width direction. Specifically, the upper end portion of the left side seal 122L is in pressure contact with the left end portion of the lower end portion of the blade 100 in the layer thickness regulating member 24 from the rear side (the back side in the drawing in FIG. 8B). The upper end portion of the side seal 122R presses the right end portion of the lower end portion of the blade 100 from the rear side.

  When the developing roller 22 is attached to the developing frame 40 as shown in FIG. 9, the outer peripheral surface on the upper rear side of the rubber roller 22 </ b> B of the developing roller 22 comes into pressure contact with the pressing portion 104 at the lower end portion of the blade 100 from the front side. Then, the substantially lower half of the blade 100 (the portion protruding downward from the first support portion 105) is slightly bent rearward, and the pressing portion 104 is developed by the restoring force (elastic force) generated in the blade 100. The outer peripheral surface on the rear upper side of the roller 22 (rubber roller 22B) is pressed from the rear side over the entire width direction. That is, the blade 100 contacts the outer peripheral surface of the rubber roller 22B along the width direction at the pressing portion 104.

  When the developing roller 22 and the layer thickness regulating member 24 are thus attached to the developing frame 40 and the developing cartridge 16 is completed, the first support portion 105 of the supporting member 101 is on the opposite side of the developing roller 22 with respect to the blade 100. positioned. Further, in the support member 101, the left and right protrusions 108 (see also FIG. 6) protrude above the first support part 105 to the upper side in the direction away from the developing roller 22 (see FIG. 2).

  Further, in this state, as described above, the left and right side seals 122 (specifically, portions below the upper end portion of each side seal 122) are at both ends in the width direction of the outer peripheral surface of the developing roller 22 (rubber roller 22B). It is in contact with the part from the rear side. Therefore, the layer thickness regulating member 24 (blade 100) pressed from the rear side by the upper ends of the left and right side seals 122 has an outer peripheral surface of the developing roller 22 and the left and right side seals 122 at both ends in the width direction of the lower ends. Between the upper end of

Therefore, in this state, with reference to FIG. 8B, the layer thickness regulating member 24 is positioned at both ends in the width direction and a pair of left and right first ranges A sandwiched between the developing roller 22 and the side seal 122. And a second range B provided between the pair of first ranges A.
Here, in the layer thickness regulating member 24, the upper end portion of the blade 100 and the first support portion 105 (see FIG. 7) of the support member 101 are not welded in the first range A, but in the width direction in the second range B. It is welded over.
(3) Mounting of Developer Cartridge on Drum Cartridge Next, mounting (detachment) of the developer cartridge 16 on the drum cartridge 15 will be described. The developing cartridge 16 is attached to and detached from the drum cartridge 15 outside the main casing 2 (see FIG. 1).

Referring to FIG. 2, when the developing cartridge 16 is attached to the drum cartridge 15, first, the handle 74 (see FIG. 3) is gripped to place the developing cartridge 16 above the attachment / detachment opening 31 of the drum cartridge 15. Deploy.
Then, the developing cartridge 16 is lowered so as to pass through the attachment / detachment port 31 in order from the developing roller 22 side at the front end, and is accommodated in the cartridge accommodating chamber 35 of the drum cartridge 15. At that time, the left and right pressing bosses 38 of the developing cartridge 16 come into contact with the pressing member 36 located on the same side in the width direction in the drum cartridge 15 from the front upper side, whereby each pressing member 36 is urged as described above. It deviates in the clockwise direction when viewed from the width direction against the urging force of a member (not shown).

As shown in FIG. 2, when the developing cartridge 16 is completely accommodated in the cartridge accommodating chamber 35, the mounting of the developing cartridge 16 to the drum cartridge 15 is completed.
In this state, the front outer peripheral surface of the rubber roller 22B of the developing roller 22 in the developing cartridge 16 is exposed to the front side from the opening 75 of the developing frame 40, and the width direction with respect to the rear outer peripheral surface of the photosensitive drum 17 of the drum cartridge 15 It faces from the rear side over the entire area.

  At this time, each pressing member 36 is counterclockwise as viewed from the width direction toward the original position before the developing cartridge 16 is mounted by the biasing force of the biasing member (not shown). At this time, the corresponding pressing boss 38 is pressed forward along the substantially horizontal direction. As a result, the entire developing cartridge 16 is urged forward, so that the developing roller 22 (rubber roller 22B) is pressed toward the photosensitive drum 17, and the front outer peripheral surface of the rubber roller 22B is brought to the rear outer peripheral surface of the photosensitive drum 17. On the other hand, it is press-contacted from the rear side over the entire width direction.

  Here, the direction in which the pressing member 36 presses the pressing boss 38, in other words, the pressing direction P of the developing roller 22 against the photosensitive drum 17 is substantially as shown by a thick dashed arrow when projected from the width direction. It is a direction toward the front side along the horizontal direction. In the layer thickness regulating member 24, since the second support portion 106 extends along the substantially horizontal direction as described above, the first support portion 105 along the pressing direction P when projected from the width direction. It can be seen that it extends from the upper end of the.

When the developing cartridge 16 is mounted on the drum cartridge 15, the above-described recess 88 on the top surface of the developing cartridge 16 is exposed upward from the attachment / detachment opening 31 of the drum cartridge 15 and the outer periphery of the photosensitive drum 17. It faces the surface from the rear upper side (see also FIG. 1).
The developer cartridge 16 can be detached from the drum cartridge 15 by grasping the handle 74 (see FIG. 3) and pulling the entire developer cartridge 16 upward from the attachment / detachment opening 31 of the drum cartridge 15.
(4) Operation in Developing Cartridge With reference to FIG. 3, at the time of image formation described above, the toner in the toner storage chamber 78 is conveyed to the front developing chamber 77 while being agitated by the rotation of the agitator 41 and supplied to the supply roller 23. To be supplied. Thereafter, in the developing chamber 77, the toner is supplied to the developing roller 22 by the rotation of the supply roller 23, and is carried on the outer peripheral surface of the rubber roller 22B of the developing roller 22.

  Here, since the developing roller 22 rotates counterclockwise in the right side view as described above, the toner carried on the outer peripheral surface of the rubber roller 22B of the developing roller 22 is rotated along with the rotation of the developing roller 22. The layer thickness regulating member 24 enters from the lower rear side between the pressing portion 104 at the lower end of the blade 100 and the outer peripheral surface of the developing roller 22 (rubber roller 22B). As described above, the toner is formed as a thin layer on the outer peripheral surface of the developing roller 22 (rubber roller 22B) while the layer thickness is regulated between the pressing portion 104 and the outer peripheral surface of the developing roller 22 (rubber roller 22B). Supported.

That is, the blade 100 controls the toner layer thickness on the outer peripheral surface of the developing roller 22 by contacting the entire width direction of the outer peripheral surface of the developing roller 22 at the pressing portion 104.
Here, the gap between the developing roller 22 and the bottom wall 44 of the developing frame 40 is closed by the lower film 80, and the gap between the blade 100 and the facing surface 66 of the developing frame 40 is closed by the seal member 119. Therefore, toner does not leak from these gaps.

  Referring to FIG. 9, the pair of left and right side seals 122 (see also FIG. 8 (b)) is rearward with respect to both ends in the width direction of the rear outer peripheral surface of the developing roller 22 (rubber roller 22B). Touching from the side. Therefore, when the developing roller 22 rotates in this state, the rear outer peripheral surfaces of both end portions in the width direction of the developing roller 22 (rubber roller 22B) rub against the side seals 122. The toner leakage from the region sandwiched between the side seals 122 to the outside in the width direction is prevented. Further, since the left and right side seals 122 are in contact with both ends in the width direction of the layer thickness regulating member 24 from the rear side (see also FIG. 8B), the left and right sides of the layer thickness regulating member 24 are Toner leakage from the region sandwiched between the seals 122 to the outside in the width direction is prevented.

That is, the left and right side seals 122 (see FIG. 8B) prevent toner leakage at both ends in the width direction of the developing roller 22 and the layer thickness regulating member 24.
As described above, the thin layer of toner carried on the outer peripheral surface of the developing roller 22 is supplied to the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 17 (see FIG. 2) as described above. Here, regarding the formation of the electrostatic latent image on the photosensitive drum 17, referring to FIG. 1, the laser beam irradiated from the exposure unit 12 to the surface of the photosensitive drum 17 moves to the front lower side as indicated by the broken line arrow. It extends in a straight line and reaches the outer peripheral surface of the photosensitive drum 17 through the concave portion 88 on the top surface of the developing cartridge 16. That is, the optical path L of the laser beam from the exposure unit 12 to the photosensitive drum 17 passes through the recess 88, that is, between the pair of left and right protrusions 108 (see FIG. 4) of the support member 101.
3. Action Effect (1) As shown in FIG. 9, in the developing cartridge 16, the developing roller 22 carrying toner on the outer peripheral surface thereof is rotatably supported by the developing frame 40. The developing cartridge 16 includes a side seal 122 and a layer thickness regulating member 24.

The side seal 122 is provided on the developing frame 40. The side seals 122 are in contact with both ends of the outer peripheral surface of the developing roller 22 in the rotation axis direction (width direction) of the developing roller 22 and prevent toner leakage at the both ends.
The layer thickness regulating member 24 is a blade 100 that regulates the layer thickness of the toner on the outer circumferential surface of the developing roller 22 by contacting the outer circumferential surface of the developing roller 22 along the width direction, and a support that supports the blade 100. Member 101.

  Here, the layer thickness regulating member 24 is sandwiched between the outer peripheral surface of the developing roller 22 and the side seal 122 at both ends in the width direction. Specifically, the layer thickness regulating member 24 is provided between the pair of first ranges A and the pair of first ranges A that are located at both ends in the width direction and sandwiched between the developing roller 22 and the side seal 122. And has a second range B (see FIG. 8B).

In such a layer thickness regulating member 24, the blade 100 and the support member 101 are not welded in the first range A, but are welded in the width direction in the second range B (see FIG. 8B). ).
Therefore, in the first range A (see FIG. 8B) sandwiched between the developing roller 22 and the side seal 122 (in other words, pressed forward toward the developing roller 22 by the side seal 122), the blade 100 is Further, the pressing force from the side seal 122 can be dispersed, and the influence of the pressing of the side seal 122 can be reduced. Thereby, the contact pressure of the blade 100 with respect to the outer peripheral surface of the developing roller 22 does not increase locally in the first range A, but becomes uniform in the entire width direction. Thereby, the local nonuniformity of the layer thickness of the toner regulated on the outer peripheral surface of the developing roller 22 by the layer thickness regulating member 24 can be suppressed.
(2) Referring to FIG. 2, the developing roller 22 supplies toner to the electrostatic latent image by being pressed toward the photosensitive drum 17 on which the electrostatic latent image is formed.

Here, the support member 101 includes a first support portion 105 welded to the blade 100 and a second support portion 106 extending from the first support portion 105.
The second support 106 extends from the first support 105 along the pressing direction P of the developing roller 22 against the photosensitive drum 17 when projected from the width direction. Therefore, even if the pressing force that presses the developing roller 22 toward the photosensitive drum 17 acts on the second support portion 106, the second support portion 106 effectively receives the pressing force, and thus includes the second support portion 106. The entire developing cartridge 16 is not easily distorted. Thereby, in the developing cartridge 16, the developing roller 22 can be uniformly pressed toward the photosensitive drum 17 over the entire region in the width direction.
(3) As shown in FIG. 7, a through hole 103 that penetrates the blade 100 in the thickness direction is formed at an end portion in the width direction of the blade 100, and an end portion in the width direction of the support member 101 is formed at the end portion in the width direction. , A convex portion 109 is provided.

  As shown in FIG. 6, the convex portion 109 is inserted into the through hole 103 and protrudes from the blade 100 in the thickness direction of the blade 100. 8B, even if the blade 100 and the support member 101 are pressed by the side seal 122 in a state where they are not welded in the first range A (the end in the width direction), It is possible to prevent the support member 101 from being unexpectedly detached (see also FIG. 9).

16 developing cartridge 17 photosensitive drum 22 developing roller 24 layer thickness regulating member 40 developing frame 100 blade 101 supporting member 103 through hole 105 first supporting portion 106 second supporting portion 109 convex portion 122 side seal A first range B second range P Pressing direction

Claims (3)

A housing,
A developer carrying member rotatably supported by the housing and carrying a developer on an outer peripheral surface;
A leakage preventing member that is provided in the housing and contacts both ends of the outer peripheral surface of the developer carrying member in the rotation axis direction of the developer carrying member, and prevents leakage of the developer at the both ends;
A blade for regulating the layer thickness of the developer on the outer peripheral surface of the developer carrying member by contacting the outer peripheral surface of the developer carrying member along the rotation axis direction; and a support member for supporting the blade A layer thickness regulating member including a layer thickness regulating member sandwiched between an outer peripheral surface of the developer carrier and the leakage preventing member at both ends in the rotation axis direction,
The layer thickness regulating member is provided between a pair of first ranges and a pair of the first ranges located at both ends in the rotation axis direction and sandwiched between the developer carrier and the leakage prevention member. A second range to be
The developing device according to claim 1, wherein the blade and the support member are not welded in the first range but are welded in the second range over the rotation axis direction. The developer carrier is pressed against a photosensitive body on which an electrostatic latent image is formed, thereby supplying the developer to the electrostatic latent image,
The support member includes a welded portion that is welded to the blade, and an extending portion that extends from the welded portion along the pressing direction of the developer carrier to the photosensitive member when projected from the rotation axis direction. The developing device according to claim 1, further comprising: A through hole that penetrates the blade in the thickness direction of the blade is formed at an end of the blade in the rotational axis direction,
The end portion in the rotation axis direction of the support member is provided with a convex portion that is inserted through the through hole and protrudes from the blade in the thickness direction of the blade. The developing device according to 1.

Images