JP6237092B2 - Developer - Google Patents

Description

  The present invention relates to a developing device provided in an image forming apparatus employing an electrophotographic system.

  As an electrophotographic image forming apparatus, an image forming apparatus including an image carrier on which an electrostatic latent image is formed and a developing cartridge that supplies a developer to the image carrier is known.

  For example, a laser printer is known that includes a process frame that includes a photosensitive drum and a developing cartridge that includes a developing roller that carries toner and is detachably attached to the process frame (see, for example, Patent Document 1 below). .)

  The developing cartridge provided in the laser printer further includes a supply roller that supplies toner to the developing roller, and a layer thickness regulating blade that regulates the thickness of the toner carried on the developing roller.

JP 2009-180772 A

  However, in the laser printer described in Patent Document 1, it is considered to increase the toner supply speed from the developing cartridge to the photosensitive drum in order to increase the printing speed.

  In order to increase the toner supply speed, it is necessary to increase the toner supply speed from the supply roller to the developing roller.

  However, if the supply speed of toner from the supply roller to the developing roller is increased, a large amount of toner may stay in the vicinity of the developing roller during the image forming operation. There is a risk of leakage from between the toner and the developing roller.

  Accordingly, an object of the present invention is to provide a developing device capable of preventing the developer from leaking from the periphery of the developing roller even when the developer supply speed to the developing roller is increased.

(1) In order to achieve the above object, a developing device of the present invention includes a housing, a developing roller, a first supply roller, a second supply roller, a layer thickness regulating member, and a transport mechanism. . The housing has an opening at one end. The developing roller is disposed in the vicinity of the opening and configured to carry the developer. The first supply roller is configured to contact the developing roller and supply the developer stored in the developer storage portion to the developing roller. The second supply roller is configured to contact the first supply roller and supply the developer to the first supply roller. The layer thickness regulating member is configured to contact the developing roller and regulate the layer thickness of the developer carried on the developing roller.

  The transport mechanism is arranged above the second supply roller in the vertical direction, and is configured to return the developer regulated by the layer thickness regulating member to the developer accommodating portion.

  According to such a configuration, the developer in the developer container is supplied to the first supply roller by the second supply roller, and then supplied to the development roller by the first supply roller.

  That is, the developer in the developer container is not supplied directly to the first supply roller, but is supplied to the first supply roller via the second supply roller, and then to the development roller via the first supply roller. Supplied.

  Thereby, it can suppress that a developer is excessively supplied to a 1st supply roller, and can suppress that a developer is excessively supplied to a developing roller by extension.

  Further, the developer supplied to the developing roller has its layer thickness regulated by the layer thickness regulating member and is carried on the surface of the developing roller.

  At this time, the developer regulated by the layer thickness regulating member is returned to the developer container by the transport mechanism.

  Thereby, it can suppress that the developer controlled by the layer thickness control member accumulates in the vicinity of the contact portion between the developing roller and the first supply roller.

  In other words, according to such a configuration, the developer regulated by the layer thickness regulating member can be prevented from being brought into contact with the developing roller and the first supply roller, while excessively supplying the developer to the developing roller can be suppressed. Accumulation in the vicinity can be suppressed.

As a result, even when the supply speed of the developer to the developing roller is increased, it is possible to suppress excessive accumulation of the developer near the contact portion between the developing roller and the first supply roller, and development from the periphery of the developing roller is possible. It is possible to prevent the agent from leaking.
(2) The first supply roller may be positioned below the upper end of the developing roller in the vertical direction. The second supply roller may be positioned below the upper end of the first supply roller in the vertical direction.

  According to such a configuration, the developer in the developer container can be supplied to the developing roller against gravity.

  Therefore, the developer that has excessively adhered to the first supply roller can be dropped by its own weight using gravity.

As a result, excessive supply of the developer to the developing roller can be further suppressed.
(3) The first straight line passing through the rotation center of the first supply roller and the rotation center of the second supply roller may be inclined so as to form a first acute angle with respect to the horizontal plane. The second straight line passing through the rotation center of the developing roller and the rotation center of the first supply roller may be inclined so as to form a second acute angle with respect to the horizontal plane. In this case, the first acute angle may be smaller than the second acute angle.

  According to such a configuration, the inclination of the second straight line, that is, the inclination from the first supply roller to the developing roller can be set relatively large.

  Therefore, the developer that has excessively adhered to the first supply roller can be reliably dropped before being supplied to the development roller.

As a result, excessive supply of the developer to the developing roller can be further suppressed.
(4) The developing device of the present invention may further include a supply unit for supplying the developer to the second supply roller.

According to such a configuration, the developer can be reliably supplied to the second supply roller by the supply unit.
(5) The developing device of the present invention may further include a developer accommodating portion that accommodates the developer on the other side opposite to the one end portion.

  According to such a configuration, the developer can be accommodated on the side opposite to the opening.

Therefore, the developer in the developer accommodating portion is supplied to the developing roller via the first supply roller and the second supply roller, and the developer regulated by the layer thickness regulating member is accommodated in the developer via the second portion. Can be recovered.
(6) The housing is disposed in a vertical direction above the first portion for supplying the developer stored in the developer storage portion to the second supply roller, and is formed by a layer thickness regulating member. You may have the 2nd part for returning the controlled developer to a developer accommodating part, and the partition wall which partitions off the 1st part and the 2nd part. In this case, the transport mechanism may be a partition wall. The partition wall may be inclined downward in the vertical direction from one end to the other side opposite to the one end.

  According to such a configuration, the developer regulated by the layer thickness regulating member can be made to flow to the other using the inclination of the partition wall.

Therefore, excessive accumulation of the developer near the contact portion between the developing roller and the first supply roller can be reliably suppressed.
(7) The transport mechanism may be a transport member that is arranged to face the layer thickness regulating member and configured to transport the developer toward the developer storage unit.

  According to such a configuration, the developer regulated by the layer thickness regulating member can be conveyed to the developer accommodating portion by the conveying member.

  Therefore, excessive accumulation of the developer near the contact portion between the developing roller and the first supply roller can be reliably suppressed.

  According to the developing device of the present invention, even when the developer supply speed to the developing roller is increased, it is possible to suppress excessive accumulation of the developer in the vicinity of the contact portion between the developing roller and the first supply roller, It is possible to prevent the developer from leaking from the periphery of the developing roller.

FIG. 1 is a side sectional view of a developing cartridge as a first embodiment of the developing device of the present invention. FIG. 2 is a central sectional view of a printer to which the developing cartridge shown in FIG. 1 is mounted. 3 is a cross-sectional view taken along the line AA of the developing cartridge shown in FIG. 4 is a cross-sectional view of the developing cartridge shown in FIG. FIG. 5 is a side sectional view showing a modified example of the developing cartridge.

1. 1. Overview of Developing Cartridge As shown in FIG. 1, a developing cartridge 1 as an example of a developing device includes a developing roller 2, a first supply roller 3, a layer thickness regulating blade 4 as an example of a layer thickness regulating member, and a developing unit. And a toner container 5 as an example of an agent container.

  In the following description, when referring to the direction of the developing cartridge 1, the state in which the developing cartridge 1 is mounted on the image forming apparatus 11 described later is used as the upper and lower reference. That is, the vertical direction is the vertical direction, and the upper side of the drawing in FIG. 1 is the upper side, and the lower side of the drawing in FIG. 1 is the lower side. Further, the right side of FIG. 1 is the front, and the left side of FIG. 1 is the rear. In addition, when the developing cartridge 1 is viewed from the front, the left and right reference is used. That is, the front side of the page of FIG. 1 is the left side, and the back side of the page of FIG. The rear is an example of one, and the front is an example of the other.

  The developing roller 2 is disposed at the rear end portion of the developing cartridge 1.

  The first supply roller 3 is disposed on the front lower side of the developing roller 2. The first supply roller 3 is in contact with the front lower end portion of the developing roller 2.

  The layer thickness regulating blade 4 is disposed on the front upper side of the developing roller 2. The layer thickness regulating blade 4 is in contact with the front end portion of the developing roller 2.

The toner container 5 is disposed at the front end of the developing cartridge 1. The toner storage unit 5 is configured to store toner as an example of a developer.
2. Use Mode of Developer Cartridge As shown in FIG. 2, the developer cartridge 1 is mounted on an image forming apparatus 11 and used.

  The image forming apparatus 11 is an electrophotographic monochrome printer. The image forming apparatus 11 includes an apparatus main body 12, a process cartridge 13, a scanner unit 14, and a fixing unit 15.

  The apparatus main body 12 has a substantially box shape. The apparatus body 12 includes an opening 16, a front cover 17, a paper feed tray 18, and a paper discharge tray 19.

  The opening 16 is disposed at the front end of the apparatus main body 12. The opening 16 communicates the inside and outside of the apparatus main body 12 in the front-rear direction so as to allow passage of the process cartridge 13.

  The front cover 17 is disposed at the front end of the apparatus main body 12. The front cover 17 has a substantially flat plate shape extending in the vertical direction. The front cover 17 can swing around its lower end as a fulcrum. The front cover 17 is configured to open or close the opening 16.

  The paper feed tray 18 is disposed at the bottom of the apparatus main body 12. The paper feed tray 18 is configured to accommodate the paper P.

  The paper discharge tray 19 is disposed on the front half of the upper wall of the apparatus main body 12. The paper discharge tray 19 is recessed downward from the upper surface of the apparatus main body 12.

  The process cartridge 13 is accommodated in the substantially vertical center of the apparatus main body 12. The process cartridge 13 is configured to be attached to or detached from the apparatus main body 12 through the opening 16. The process cartridge 13 includes a drum cartridge 20 and a developing cartridge 1.

  The drum cartridge 20 includes a photosensitive drum 21, a scorotron charger 22, and a transfer roller 23.

  The photosensitive drum 21 is rotatably supported at the rear end portion of the drum cartridge 20.

  The scorotron charger 22 is disposed in front of and above the photosensitive drum 21 at a distance from the photosensitive drum 21.

  The transfer roller 23 is disposed below the photosensitive drum 21. The transfer roller 23 is in contact with the rear lower end portion of the photosensitive drum 21.

  The developing cartridge 1 is mounted on the drum cartridge 20 in front of the photosensitive drum 21 so that the developing roller 2 contacts the front lower end portion of the photosensitive drum 21.

  The scanner unit 14 is disposed above the process cartridge 13. The scanner unit 14 is configured to emit a laser beam based on image data toward the photosensitive drum 21.

  The fixing unit 15 is disposed on the rear upper side of the process cartridge 13. The fixing unit 15 includes a heating roller 24 and a pressure roller 25 pressed against the rear end portion of the heating roller 24.

  When the image forming apparatus 11 starts an image forming operation, the scorotron charger 22 uniformly charges the surface of the photosensitive drum 21. The scanner unit 14 exposes the surface of the photosensitive drum 21. Thereby, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 21.

  Further, the toner in the toner container 5 is frictionally charged positively between the developing roller 2 and the first supply roller 3 and is carried on the developing roller 2. The layer thickness regulating blade 4 regulates the layer thickness of the toner carried on the developing roller 2 to a constant thickness.

  Then, the toner carried on the developing roller 2 is supplied to the electrostatic latent image on the surface of the photosensitive drum 21. As a result, the toner image is carried on the surface of the photosensitive drum 21.

  The paper P is fed from the paper feed tray 18 between the photosensitive drum 21 and the transfer roller 23 one by one at a predetermined timing by the rotation of various rollers. The toner image on the surface of the photosensitive drum 21 is transferred to the paper P when the paper P passes between the photosensitive drum 21 and the transfer roller 23.

Thereafter, the sheet P is heated and pressed when passing between the heating roller 24 and the pressure roller 25. As a result, the toner image on the paper P is thermally fixed to the paper P. Thereafter, the paper P is discharged to the paper discharge tray 19.
3. 1. Details of Developing Cartridge (1) Configuration of Developing Cartridge As shown in FIG. 1, the developing cartridge 1 includes a developing frame 31, an example of a housing, a developing roller 2, a first supply roller 3, and a second supply member. A second supply roller 41 as an example, a screw 42 as an example of a supply means, a layer thickness regulating blade 4, a first conveyance member 43 as an example of a conveyance mechanism and a conveyance member, and a second conveyance member 44 And an agitator 6.
(1-1) Development Frame The development frame 31 includes the toner storage unit 5 and the development unit 33 described above.

  As shown in FIGS. 1, 3, and 4, the toner container 5 constitutes the front half of the developing frame 31. The toner container 5 has a substantially cylindrical shape extending in the left-right direction and closed at both left and right ends. The toner storage unit 5 includes a supply port 34, a return port 32, and a recovery port 35.

  The supply port 34 is disposed at the right end portion of the rear peripheral wall of the toner storage unit 5. The supply port 34 penetrates the rear peripheral wall of the toner storage portion 5 in the front-rear direction.

  The return port 32 is disposed at a position overlapping the supply port 34 when viewed in the left-right direction at the left end portion of the rear peripheral wall of the toner storage unit 5. The return port 32 penetrates the rear peripheral wall of the toner storage portion 5 in the front-rear direction.

  The collection port 35 is disposed at the left end of the rear peripheral wall of the toner storage unit 5 above the return port 32. The collection port 35 penetrates the rear peripheral wall of the toner storage unit 5 in the front-rear direction.

  The developing unit 33 continues to the rear of the toner storage unit 5 and constitutes the rear half of the developing frame 31. The developing unit 33 has a substantially prismatic shape extending in the left-right direction and closed at both left and right ends. The developing unit 33 includes a pair of side walls 36, a lower wall 37, an upper wall 38, and a partition wall 40.

  Each of the pair of side walls 36 is disposed at each of both ends of the developing unit 33 in the left-right direction. Each of the pair of side walls 36 has a flat plate shape that is substantially rectangular in a side view. Each of the pair of side walls 36 continuously extends forward from the respective rear end portions of both side walls in the left-right direction of the toner storage portion 5. The rear end portions of each of the pair of side walls 36 bulge outward in the left-right direction at a portion supporting the developing roller 2 and the first supply roller 3.

  The lower wall 37 is disposed at the lower end of the developing unit 33. The lower wall 37 has a substantially flat plate shape extending in the front-rear direction. The front end portion of the lower wall 37 is continuous with the rear peripheral wall of the toner storage portion 5 below the supply port 34 and the return port 32. Each of the left and right ends of the lower wall 37 is continuous with the lower ends of the pair of side walls 36.

  The upper wall 38 is disposed at the upper end portion of the developing unit 33. The upper wall 38 has a substantially flat plate shape extending in the front-rear direction. The front end portion of the upper wall 38 is continuous with the upper end portion of the toner storage portion 5 above the collection port 35. Each of the left and right ends of the upper wall 38 is continuous with the upper ends of the pair of side walls 36. The rear end portion of the upper wall 38 is disposed at an interval above and in front of the rear end portion of the lower wall 37. The rear end of the upper wall 38, together with the rear end of the pair of side walls 36 and the rear end of the lower wall 37, defines an opening 39. That is, the developing frame 31 has an opening 39 at the rear end.

The partition wall 40 is disposed substantially at the center in the vertical direction of the developing unit 33. The partition wall 40 has a substantially flat plate shape extending in a direction connecting the rear upper part and the front lower part. That is, the partition wall 40 is inclined downward as it goes forward. The front end portion of the partition wall 40 is continuous with the rear peripheral wall of the toner storage portion 5 above the supply port 34 and the return port 32 and below the recovery port 35. The rear end portion of the partition wall 40 is disposed slightly forward in front of the upper end portion of the first supply roller 3. The partition wall 40, the toner supply chamber 51 as an example of a first portion below the partition wall 40, and a toner recovery chamber as an example of a second portion above the partition wall 40, in the internal space of the developing unit 33. It is divided into 52. Specifically, the toner supply chamber 51 is defined by a pair of side walls 36, a lower wall 37, a rear peripheral wall of the toner storage portion 5, the first supply roller 3, and the partition wall 40. The toner collection chamber 52 is defined by a pair of side walls 36, an upper wall 38, a rear peripheral wall of the toner storage portion 5, the developing roller 2, the first supply roller 3, the layer thickness regulating blade 4, and the partition wall 40. .
(1-2) Configuration Other than Developing Frame The developing roller 2 is disposed inside the opening 39 of the developing frame 31, that is, in the vicinity thereof. The developing roller 2 includes a developing roller shaft 2A, a developing roller main body 2B, and a developing roller driving gear 2C.

  The developing roller shaft 2A has a substantially cylindrical shape. The developing roller shaft 2A extends in the left-right direction. The developing roller shaft 2A is made of metal. Each of the left and right ends of the developing roller shaft 2A is rotatably supported by the pair of side walls 36. The left end portion of the developing roller shaft 2A protrudes leftward from the left side wall 36.

  The developing roller body 2B has a substantially cylindrical shape. The developing roller body 2B extends in the left-right direction. The developing roller body 2B is made of conductive rubber. The developing roller body 2B does not cover the left and right ends of the developing roller shaft 2A, but covers the substantially horizontal center of the developing roller shaft 2A.

  The developing roller drive gear 2C is supported on the left end of the developing roller shaft 2A so as not to rotate relative to the left side wall 36. The developing roller drive gear 2C has a substantially disc shape having a thickness in the left-right direction. The developing roller drive gear 2C has gear teeth over the entire peripheral surface thereof.

  The first supply roller 3 is disposed below the upper end of the developing roller 2 at the front lower side of the developing roller 2. A straight line L1 as an example of a second straight line passing through the rotation center A1 of the developing roller 2 and the rotation center A2 of the first supply roller 3 forms an angle θ1 as an example of a second acute angle with respect to the horizontal plane H. It is inclined to. The angle θ1 is, for example, 30 ° to 80 °, and in this embodiment, for example, 40 °. In addition, the first supply roller 3 is disposed slightly behind the rear end portion of the partition wall 40 at a slight interval. The first supply roller 3 is upstream in the counterclockwise direction when viewed from the left side with respect to the contact portion N1 with the developing roller 2 and is in the counterclockwise direction when viewed from the left side with respect to a contact portion N2 with the second supply roller 41 described later. It faces the rear end of the partition wall 40 at the downstream side. The first supply roller 3 includes a first supply roller shaft 3A, a first supply roller main body 3B, and a first supply roller drive gear 3C.

  The first supply roller shaft 3A has a substantially cylindrical shape. The first supply roller shaft 3A extends in the left-right direction. The first supply roller shaft 3A is made of metal. Each of the left and right ends of the first supply roller shaft 3A is rotatably supported by a pair of side walls 36. The left end portion of the first supply roller shaft 3A protrudes leftward from the left side wall 36.

  The first supply roller body 3B has a substantially cylindrical shape. The first supply roller body 3B extends in the left-right direction. The first supply roller body 3B is made of a conductive sponge. The first supply roller main body 3B does not cover the left and right ends of the first supply roller shaft 3A, and covers the approximate center in the left-right direction of the first supply roller shaft 3A. The first supply roller main body 3B is in contact with the front lower end portion of the developing roller main body 2B.

  The first supply roller drive gear 3C is supported on the left end of the first supply roller shaft 3A so as not to rotate relative to the left side of the left side wall 36. The first supply roller drive gear 3C has a substantially disc shape having a thickness in the left-right direction. The first supply roller drive gear 3C has gear teeth over the entire peripheral surface.

  The second supply roller 41 is disposed below the upper end of the first supply roller 3 at the front lower side of the first supply roller 3. A straight line L2 as an example of a first straight line passing through the rotation center A2 of the first supply roller 3 and the rotation center A3 of the second supply roller 41 has an angle θ2 as an example of a first acute angle with respect to the horizontal plane H. It is inclined to make. The angle θ2 is smaller than the angle θ1, for example, 15 ° to 45 °, and in this embodiment, for example, 25 °. The second supply roller 41 includes a second supply roller shaft 41A, a second supply roller main body 41B, and a second supply roller drive gear 41C.

  The second supply roller shaft 41A has a substantially cylindrical shape. The second supply roller shaft 41A extends in the left-right direction. The second supply roller shaft 41A is made of metal. Each of the left and right ends of the second supply roller shaft 41A is rotatably supported by the pair of side walls 36. The left end portion of the second supply roller shaft 41A protrudes leftward from the left side wall 36.

  The second supply roller main body 41B has a substantially cylindrical shape. The second supply roller main body 41B extends in the left-right direction. The second supply roller body 41B is made of a conductive sponge. The sponge bubbles in the second supply roller body 41B are larger than the sponge bubbles in the first supply roller body 3B. The sponge of the second supply roller body 41B is softer than the sponge of the first supply roller body 3B. With such a configuration, the second supply roller main body 41B can increase the toner conveying force than the first supply roller main body 3B, and can reduce stress on the toner (such as friction against the surface of the toner particles). can do. The second supply roller main body 41B does not cover the left and right ends of the second supply roller shaft 41A, but covers the substantially center in the left-right direction of the second supply roller shaft 41A. The second supply roller main body 41B is in contact with the front lower end portion of the first supply roller main body 3B.

  The second supply roller drive gear 41C is supported on the left end portion of the second supply roller shaft 41A so as not to be relatively rotatable. The second supply roller drive gear 41C has a substantially disc shape having a thickness in the left-right direction. The second supply roller drive gear 41C has gear teeth over the entire peripheral surface.

  The screw 42 is disposed in the toner supply chamber 51 with a space in front of the second supply roller 41. The screw 42 is a left-handed auger screw extending in the left-right direction. Each of the left and right ends of the screw 42 is rotatably supported by the pair of side walls 36. The left end portion of the screw 42 protrudes leftward from the left side wall 36. The screw 42 includes a screw drive gear 45.

  The screw drive gear 45 is supported on the left end of the screw 42 so as not to rotate relative to the left side of the left side wall 36. The screw drive gear 45 has a substantially disc shape having a thickness in the left-right direction. The screw drive gear 45 has gear teeth all over its peripheral surface.

  The layer thickness regulating blade 4 has a substantially flat plate shape extending in the vertical direction. The upper end portion of the layer thickness regulating blade 4 is fixed to the rear end portion of the upper wall 38. The lower end portion of the layer thickness regulating blade 4 is in contact with the rear end portion of the developing roller main body 2B.

  The first conveying member 43 is disposed above the first supply roller 3 in front of the layer thickness regulating blade 4. The first transport member 43 includes a rotation shaft 43A, a plurality of blades 43B, and a first transport member drive gear 43C.

  The rotating shaft 43A has a substantially cylindrical shape extending in the left-right direction. Each of the left and right ends of the rotating shaft 43A is rotatably supported by each of the pair of side walls 36. The left end portion of the rotation shaft 43A protrudes leftward from the left side wall 36.

  Each of the plurality of blades 43B is arranged in parallel in the left-right direction. Each of the plurality of blades 43B is made of a flexible material such as a resin film, and has a substantially rectangular flat plate shape extending from the outer peripheral surface of the rotation shaft 43A toward the radial direction outward of the rotation shaft 43A.

  The first conveying member drive gear 43C is supported on the left end portion of the rotation shaft 43A so as not to rotate relative to the left side of the left side wall 36. The first conveying member drive gear 43C has a substantially disk shape having a thickness in the left-right direction. The first conveying member drive gear 43C has gear teeth over the entire peripheral surface thereof.

  The second transport member 44 is disposed behind the collection port 35 with a space in front of the first transport member 43. The second transport member 44 includes a rotation shaft 44A, a plurality of blades 44B, and a second transport member drive gear 44C.

  The rotating shaft 44A has a substantially cylindrical shape extending in the left-right direction. Each of both ends in the left-right direction of the rotation shaft 44A is rotatably supported by each of the pair of side walls 36. The left end portion of the rotation shaft 44A protrudes leftward from the left side wall 36.

  Each of the plurality of blades 44B is arranged in parallel in the left-right direction. Each of the plurality of blades 44B is made of a flexible material such as a resin film, and has a substantially rectangular flat plate shape extending from the outer peripheral surface of the rotating shaft 44A toward the radially outer side of the rotating shaft 44A. The free end portion (the outer end portion in the radial direction of the rotation shaft 44A) of the blade 44B is inclined so that the length (free length) from the rotation shaft 44A becomes shorter toward the right.

  The second conveying member drive gear 44C is supported on the left end portion of the rotation shaft 44A so as not to rotate relative to the left side of the left side wall 36. The second conveying member drive gear 44C has a substantially disk shape having a thickness in the left-right direction. The second conveying member drive gear 44C has gear teeth over the entire peripheral surface thereof.

  The agitator 6 is disposed in the toner storage unit 5. The agitator 6 includes an agitator shaft 6A, a plurality of stirring blades 6B, and an agitator drive gear 6C.

  The agitator shaft 6 </ b> A is disposed substantially at the center in the radial direction of the toner storage unit 5. The agitator shaft 6A has a substantially cylindrical shape extending in the left-right direction. The left and right end portions of the agitator shaft 6A are rotatably supported on the left and right side walls of the toner storage portion 5, respectively. The left end portion of the agitator shaft 6 </ b> A protrudes leftward from the left wall of the toner storage unit 5.

  Each of the plurality of stirring blades 6B is arranged in parallel in the left-right direction. Each of the plurality of stirring blades 6B is made of a flexible material such as a resin film, and has a substantially rectangular flat plate shape extending from the outer peripheral surface of the agitator shaft 6A toward the radially outer side of the agitator shaft 6A. . Each free end of the plurality of stirring blades 6B is curved so that the length (free length) from the agitator shaft 6A becomes shorter toward the left.

The agitator drive gear 6C is supported on the left end of the agitator shaft 6A so as not to rotate relative to the left side wall 36. The agitator drive gear 6C has a substantially disk shape having a thickness in the left-right direction. The agitator drive gear 6C has gear teeth over the entire peripheral surface thereof.
(2) Driving of developing cartridge and supply of electric power to developing cartridge When the above-described image forming operation is started, the apparatus main body 12 inputs a driving force to the developing cartridge 1 and supplies electric power.

  When the apparatus main body 12 inputs a driving force to the developing cartridge 1, the developing roller driving gear 2C, the first supply roller driving gear 3C, the second supply roller driving gear 41C, the screw driving gear 45, the first conveying member driving gear 43C, The driving force is transmitted to the two conveying member driving gear 44C and the agitator driving gear 6C.

  Then, as shown in FIG. 1, the developing roller 2, the first supply roller 3, the second supply roller 41, the screw 42, the first conveyance member 43, and the second conveyance member 44 rotate counterclockwise as viewed from the left side. . Further, the agitator 6 rotates in the clockwise direction when viewed from the left side.

When the apparatus main body 12 supplies power to the developing cartridge 1, for example, a developing bias of + 500V is applied to the developing roller shaft 2A, and a first supplying bias of, for example, + 550V is applied to the first supply roller shaft 3A. For example, a second supply bias of +600 V is applied to the second supply roller shaft 41A.
4). Toner Supply Operation As shown in FIGS. 1 and 3, when the developing cartridge 1 is driven, the toner in the toner storage unit 5 is conveyed rightward in the toner storage unit 5 by the rotation of the agitator 6 and supplied. The toner is supplied into the toner supply chamber 51 through the port 34.

  The toner supplied into the toner supply chamber 51 is conveyed from the right to the left in the front end portion of the toner supply chamber 51 by the rotation of the screw 42, and in the middle of the toner supply chamber 51, the toner is supplied to the foamed portion on the surface of the second supply roller 41. Adhere to.

  The toner that has not adhered to the second supply roller 41 is continuously conveyed from the right to the left in the front end portion of the toner supply chamber 51 by the rotation of the screw 42, and is supplied to the toner storage unit 5 through the return port 32. Collected in. That is, the toner is circulated between the toner supply chamber 51 and the toner storage unit 5.

  The toner adhering to the surface of the second supply roller 41 is frictionally charged at the contact portion N2 between the first supply roller 3 and the second supply roller 41, and is electrostatically carried on the surface of the first supply roller 3.

  The toner carried on the surface of the first supply roller 3 is frictionally charged again at the contact portion N1 between the developing roller 2 and the first supply roller 3, and is electrostatically carried on the surface of the developing roller 2. As described above, the toner in the toner container 5 is supplied to the developing roller 2 through the toner supply chamber 51.

  The thickness of the toner carried on the surface of the developing roller 2 is regulated by the layer thickness regulating blade 4 so as to be a thin layer having a constant thickness.

  At this time, surplus toner out of the toner carried on the surface of the developing roller 2 is scraped off by the layer thickness regulating blade 4 at the contact portion N3 between the developing roller 2 and the layer thickness regulating blade 4.

  The toner scraped off by the layer thickness regulating blade 4 falls to the vicinity of the contact portion N1 between the developing roller 2 and the first supply roller 3 due to its own weight.

  The toner that has dropped near the contact portion N1 between the developing roller 2 and the first supply roller 3 is conveyed forward by the rotation of the first conveying member 43 as shown in FIGS.

Then, the toner conveyed by the first conveying member 43 slides down along the inclination of the partition wall 40. The toner that has slid down does not return to the rear due to the inclination of the partition wall 40, but is conveyed from right to left by the rotation of the second conveying member 44, and is collected into the toner storage unit 5 through the collection port 35. . In this way, the toner scraped off by the layer thickness regulating blade 4 passes through the toner collection chamber 52 and is collected in the toner storage portion 5.
5. Operation and Effect (1) According to the developing cartridge 1, as shown in FIGS. 1 and 3, the toner in the toner supply chamber 51 is supplied to the first supply roller 3 and the second supply by the rotation of the second supply roller 41. The toner is supplied to the first supply roller 3 at a contact portion N2 with the roller 41.

  The toner supplied to the first supply roller 3 is supplied to the developing roller 2 at the contact portion N <b> 1 between the developing roller 2 and the first supply roller 3 by the rotation of the first supply roller 3.

  That is, the toner in the toner supply chamber 51 is not supplied directly to the first supply roller 3 but is supplied to the first supply roller 3 through the second supply roller 41, and then through the first supply roller 3. To the developing roller 2.

  At this time, the toner is frictionally charged at a contact portion N2 between the first supply roller 3 and the second supply roller 41 and a contact portion N1 between the developing roller 2 and the first supply roller 3.

  As a result, it is possible to suppress excessive supply of toner including uncharged toner to the first supply roller 3, and as a result, excessive supply of toner to the developing roller 2 can be suppressed.

  Further, as shown in FIGS. 1 and 4, the toner supplied to the developing roller 2 is regulated in layer thickness at the contact portion N3 between the developing roller 2 and the layer thickness regulating blade 4 by the rotation of the developing roller 2. It is carried on the surface of the developing roller 2.

  At this time, the toner regulated by the layer thickness regulating blade 4 is regulated to return directly into the toner supply chamber 51 by the partition wall 40, and the toner collection is performed by the rotation of the first conveyance member 43 and the second conveyance member 44. It passes through the chamber 52 and is returned to the toner storage unit 5.

  Thereby, it is possible to suppress the toner regulated by the layer thickness regulating blade 4 from being accumulated in the contact portion N1 between the developing roller 2 and the first supply roller 3.

  That is, according to the developing cartridge 1, the toner regulated by the layer thickness regulating blade 4 is brought into contact with the developing roller 2 and the first supply roller 3 while suppressing excessive supply of toner to the developing roller 2. Accumulation in the portion N1 can be suppressed.

Therefore, even when the toner supply speed to the developing roller 2 is increased, it is possible to suppress the toner from being excessively accumulated in the contact portion N1 between the developing roller 2 and the first supply roller 3, and the toner from the periphery of the developing roller 2 can be suppressed. Can be prevented from leaking.
(2) According to the developing cartridge 1, as shown in FIG. 1, the partition wall 40 is downstream of the contact portion N2 between the first supply roller 3 and the second supply roller 41 in the counterclockwise direction when viewed from the left side. Further, it faces the first supply roller 3 upstream of the contact portion N1 between the developing roller 2 and the first supply roller 3 in the counterclockwise direction when viewed from the left side.

  Therefore, it is possible to reliably restrict the toner regulated by the layer thickness regulating blade 4 from returning directly into the toner supply chamber 51.

  Even if the toner in the toner supply chamber 51 is excessively supplied to the first supply roller 3 by the second supply roller 41, the first supply is performed by the portion of the partition wall 40 facing the first supply roller 3. The amount carried on the roller 3 is suppressed.

For this reason, it is possible to suppress the toner from being excessively carried on the first supply roller 3, and thus to suppress the toner from being excessively supplied to the developing roller 2.
(3) According to the developing cartridge 1, as shown in FIG. 1, the first supply roller 3 is positioned below the upper end of the developing roller, and the second supply roller 41 is connected to the first supply roller 3. It is located below the upper end.

  Therefore, the toner in the toner supply chamber 51 can be supplied to the developing roller 2 against gravity.

  Thereby, the toner excessively adhered to the first supply roller 3 can be dropped by its own weight using gravity.

As a result, excessive supply of toner to the developing roller 2 can be further suppressed.
(4) According to the developing cartridge 1, as shown in FIG. 1, an angle formed by a straight line L2 passing through the rotation center A2 of the first supply roller 3 and the rotation center A3 of the second supply roller 41 with respect to the horizontal plane H θ2 is smaller than an angle θ1 formed by a straight line L1 passing through the rotation center A1 of the developing roller 2 and the rotation center A2 of the first supply roller 3 with respect to the horizontal plane H.

  Therefore, the inclination from the first supply roller 3 toward the developing roller 2 can be set relatively large.

  Thereby, the toner excessively adhered to the first supply roller 3 can be surely dropped before being supplied to the developing roller 2.

  The second supply roller 41 is disposed in the rear end portion of the toner supply chamber 51 and is spaced rearward from the supply port 34. Therefore, the toner that has entered the toner supply chamber 51 through the supply port 34 accumulates in front of the second supply roller 41 in the toner supply chamber 51 and is not directly supplied to the second supply roller 41.

  The toner accumulated in front of the second supply roller 41 is supplied to the second supply roller 41 while being stirred by the screw 42.

  Thereby, it is possible to suppress the toner in the toner supply chamber 51 from being excessively supplied to the second supply roller 41.

As a result, excessive supply of toner to the developing roller 2 can be further suppressed.
(5) The developer cartridge 1 further includes a screw 42 for supplying toner to the second supply roller 41 as shown in FIG.

Therefore, the toner can be reliably supplied to the second supply roller 41 by the screw 42.
(6) According to the developing cartridge 1, as shown in FIG. 1, the front end portion includes the toner storage portion 5 that stores toner.

  Therefore, the toner can be stored on the side opposite to the opening 39, and the toner in the toner storage portion 5 is supplied to the developing roller 2 via the first supply roller 3 and the second supply roller 41, and the layer thickness is regulated. The toner regulated by the blade 4 can be collected in the toner container 5 via the toner collection chamber 52.

Also, the overall height (vertical dimension) of the developing cartridge 1 can be kept low.
(7) According to the developing cartridge 1, as shown in FIG. 1, the partition wall 40 is inclined downward as it goes forward from the rear end.

  Therefore, the toner regulated by the layer thickness regulating blade 4 can flow forward using the inclination of the partition wall 40.

As a result, excessive accumulation of toner at the contact portion N1 between the developing roller 2 and the first supply roller 3 can be reliably suppressed.
(8) According to the developing cartridge 1, as shown in FIG. 1, the first conveying member 43 faces the layer thickness regulating blade 4 and conveys the toner forward toward the toner containing portion 5.

  Therefore, the toner regulated by the layer thickness regulating blade 4 can be conveyed to the toner storage unit 5 by the first conveying member 43.

As a result, excessive accumulation of toner at the contact portion N1 between the developing roller 2 and the first supply roller 3 can be reliably suppressed.
6). Modification (1) In the embodiment described above, the toner regulated by the layer thickness regulating blade 4 is conveyed forward by the rotation of the first conveying member 43 and the inclination of the partition wall 40. As shown in FIG. 5, the first transport member 43 may not be provided.

In this case, the developing cartridge 1 is mounted in the apparatus main body 12 so as to be inclined so that the front end portion is positioned below the rear end portion, and the toner regulated by the layer thickness regulating blade 4 is the toner. It is transported forward only by the partition wall 40 as an example of a transport mechanism having an inclination greater than the angle of repose.
(2) In the above-described embodiment, the second conveying member 44 is provided, and the toner regulated by the layer thickness regulating blade 4 is moved forward by the rotation of the first conveying member 43 and the inclination of the partition wall 40. Although the toner is transported and recovered from the recovery port 35 into the toner storage unit 5 by the rotation of the second transport member 44, the first transport member 43 and the second transport member 44 may not be provided.

In this case, the developing cartridge 1 is mounted in the apparatus main body 12 with an inclination so that the front end portion is positioned below the rear end portion, and the toner regulated by the layer thickness regulating blade 4 It is conveyed forward only by the inclination of the wall 40 and is collected in the toner storage unit 5 through the collection port 35.
(3) Further, as shown in FIG. 5, the shape of the rear end portion of the partition wall 40 is configured not only to face the first supply roller 3 but also to cover the upper part of the surface of the first supply roller 3. May be.

With such a configuration, it is possible to further suppress the toner regulated by the layer thickness regulating blade 4 from staying at the contact portion N1.
(4) In the above-described embodiment, the developing cartridge 1 includes the developing frame 31 integrally including the toner storage unit 5 and the developing unit 33. For example, the toner storage unit 5 is connected to the developing unit 33. It can also be configured to be detachable.
(5) In the above-described embodiment, both the first supply roller 3 and the second supply roller 41 rotate counterclockwise when viewed from the left side, but the first supply roller 3 is counterclockwise when viewed from the left side. The second supply roller 41 may rotate clockwise as viewed from the left side. In this case, the first supply roller 3 and the second supply roller 41 may rotate at different peripheral speeds.
(6) In the above-described embodiment, the developer cartridge 1 includes the toner container 5 as an example of the developer container. For example, the toner cartridge 5 is provided between the toner container 5 and the toner supply chamber 51. It is also possible to provide a second toner storage chamber for temporarily storing the toner conveyed from the storage unit 5 to the toner supply chamber 51 and return the toner from the toner recovery chamber 52 to the second toner storage chamber. In this case, the second toner storage chamber functions as a developer storage section.

DESCRIPTION OF SYMBOLS 1 Developing cartridge 2 Developing roller 3 1st supply roller 4 Layer thickness regulation blade 5 Toner accommodating part 31 Developing frame 39 Opening 40 Partition wall 41 2nd supply roller 42 Screw 43 1st conveyance member 51 Toner supply chamber 52 Toner collection chamber A1 rotation Center A2 Center of rotation A3 Center of rotation L1 Straight line L2 Straight line θ1 Angle θ2 Angle H Horizontal plane

Claims (8)

Have a opening at one end, a housing having a developer accommodating portion for accommodating the developer,
An agitator configured to agitate the developer in the developer container; and
A developing roller disposed in the vicinity of the opening and configured to carry a developer;
In contact with the developing roller, a first feed roller configured to supply the developer accommodated in said developer accommodating portion to said developing roller,
A second supply roller configured to contact the first supply roller and supply developer to the first supply roller;
A layer thickness regulating member configured to regulate the layer thickness of the developer carried on the developing roller in contact with the developing roller;
Than said second supply roller disposed above the vertical, Bei example a configured transport mechanism to the developer regulated by said layer thickness regulating member is returned to the developer accommodating portion,
The housing is
A first portion for supplying the developer accommodated in the developer accommodating portion to the second supply roller;
A second portion for returning the developer, which is disposed above the first portion in the vertical direction and regulated by the layer thickness regulating member, to the developer accommodating portion;
A partition wall that partitions the first portion and the second portion;
A peripheral wall of the developer accommodating portion, which partitions the first portion and the developer accommodating portion, and also partitions the second portion and the developer accommodating portion, wherein the first portion and the developer accommodating portion A peripheral wall having a supply port for communicating with the developer accommodating portion, and a recovery port for communicating with the second portion and the developer accommodating portion;
Have
The developing device according to claim 1, wherein the supply port is located at a distance from the recovery port in a direction in which the developing roller extends . The first supply roller is positioned below the upper end of the developing roller in the vertical direction,
The developing device according to claim 1, wherein the second supply roller is positioned below an upper end portion of the first supply roller in the vertical direction. A first straight line passing through the rotation center of the first supply roller and the rotation center of the second supply roller is inclined to form a first acute angle with respect to a horizontal plane;
A second straight line passing through the rotation center of the developing roller and the rotation center of the first supply roller is inclined so as to form a second acute angle with respect to a horizontal plane;
The developing device according to claim 2, wherein the first acute angle is smaller than the second acute angle.   The developing device according to claim 1, further comprising supply means for supplying a developer to the second supply roller. 5. The developing device according to claim 1, wherein the developer accommodating portion is located on the other side opposite to the one end portion. 6. Before Symbol transport mechanism is the partition wall,
6. The partition wall according to claim 1, wherein the partition wall is inclined downward in the vertical direction from the one end portion toward the other side opposite to the one end portion. Developer unit.   6. The transport mechanism according to claim 1, wherein the transport mechanism is a transport member that is arranged to face the layer thickness regulating member and configured to transport the developer toward the developer accommodating portion. The developing device according to any one of the above.   The peripheral wall is a return port that communicates the first portion with the developer accommodating portion, and is a return port that is located at a distance from the supply port in a direction in which the developing roller extends. In the rotational direction of the agitator, it has a return port positioned at an interval with respect to the recovery port,
  The screw provided in the first portion, further comprising a screw configured to convey the developer from the supply port toward the return port. The developing device according to any one of the above.

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