WO2014010131A1 - Image formation device - Google Patents

Description

Image forming apparatus

The present invention relates to an image forming apparatus employing an electrophotographic system.

As an electrophotographic image forming apparatus, a printer having a developing roller for carrying toner and a blade for regulating the toner layer thickness is known.

The blade is brought into contact with the surface of the rotating developing roller, thereby regulating the layer thickness of the toner carried on the surface of the developing roller passing through the contact portion.

As such a blade, for example, it has a plate-like member made of a metal material having elasticity, the plate-like member is formed to have a bent portion bent at a predetermined curvature radius, and the ridge line of the bent portion is There has been proposed a thinning blade that is in contact with the surface of the developing roller so as to be orthogonal to the surface movement direction of the developing roller (see, for example, Patent Document 1).

JP 2008-139552 A

However, in the printer of Patent Document 1, the tip of the bent portion of the blade faces upward from the horizontal direction.

The toner scraped off by the blade stays on the lower surface of the bent portion of the blade so as to be dammed up on the upstream side of the blade in contact with the developing roller in the rotation direction.

[When the toner staying in such a manner gradually increases, it rides on the upper surface of the bent portion of the blade.

When the tip of the bent part of the blade faces upward from the horizontal direction, the toner riding on the upper surface of the bent part of the blade is accumulated and fixed.

When the adhered toner gradually grows, it may hang down again from the upper surface of the bent portion and come into contact with the surface of the developing roller.

In such a case, the toner carried on the surface of the developing roller is dammed up by the toner that hangs down from the blade, resulting in a vertical stripe-like printing defect in which an image is not partially formed.

Therefore, an object of the present invention is to provide an image forming apparatus capable of reducing the accumulation and fixing of toner on a blade and suppressing the occurrence of printing defects.

(1) In order to solve the above-described problems, an image forming apparatus according to the present invention includes a housing for containing a developer, a developer carrying member that is rotatable with respect to the housing and carries the developer. And a blade for regulating the thickness of the developer carried on the developer carrying member.

The blade includes a base end portion supported by the housing and a tip end portion disposed on the developer carrier side.

The tip portion includes a contact portion that comes into contact with the peripheral surface of the developer carrier, and a separation portion that is separated from the surface of the developer carrier as it goes from the contact portion toward the tip.

The tip of the separation part is facing down from the horizontal direction.

According to such a configuration, the tip of the separation portion is directed downward from the horizontal direction.

Therefore, on the upstream side in the rotation direction of the developer carrier relative to the contact portion of the blade, even if the developer that is scraped off by the blade and stays on the lower surface of the separation portion runs on the upper surface of the separation portion, It slides down by gravity from the tip of the separation part.

As a result, it is possible to reduce the accumulation and fixing of the developer on the upper surface of the separation portion, and it is possible to suppress the occurrence of printing defects.
(2) Moreover, the base end part may be arrange | positioned with respect to the perpendicular line which passes a contact part on the opposite side to the rotation center of a developer carrier.

According to such a configuration, the base end portion of the blade is inclined toward the side opposite to the rotation center of the developer carrying member with respect to the vertical line passing through the contact portion as it goes from the contact portion to the base end portion. Are arranged as follows.

Therefore, even if the developer scatters and adheres between the base end portion and the tip end portion of the blade, the developer slides down due to gravity.

As a result, it is possible to reduce the accumulation and fixing of the developer between the base end portion and the tip end portion of the blade, and it is possible to suppress the occurrence of printing defects.
(3) The image forming apparatus further includes a transport member for transporting the developer to the developer carrying member, and the transport member extends from the rotation shaft to the radially outer side of the rotation shaft. The casing may include an upper wall facing the rotation shaft from above, and the blade may be configured to contact the upper wall by rotating the rotation shaft.

According to such a configuration, the blades of the conveying member come into contact with the upper wall, so that the housing that accommodates the developer is more rotationally positioned than the blades and the upper wall with the contact position of the blade and the upper wall as a boundary. It is divided into an upstream side and a downstream side.

Since the blade abuts against the upper wall while lifting the developer, the amount of developer is relatively smaller in the region partitioned on the upstream side than the region partitioned on the downstream side.

For this reason, the developer on the developer carrier side can easily return to the region partitioned on the upstream side. As a result, it is possible to reduce the adhesion of the developer to the blade.
(4) Moreover, the upper wall may protrude partially below so that it may contact with a blade | wing.

According to such a configuration, the blades of the conveying member are securely in contact with the upper wall. Therefore, the upstream side and the downstream side in the rotation direction are surely partitioned by the blades and the upper wall.

As a result, it becomes easier for the developer on the developer carrier side to return to the region partitioned upstream, and the adhesion of the developer to the blade can be reduced.
(5) Further, the housing is partitioned into a developer storage chamber for storing the developer and a development chamber for communicating with the developer storage chamber and for storing the developer carrier. The inner side surface of the bottom wall of the casing that defines the chamber may be disposed at a lower position in the vertical direction than the inner side surface of the bottom wall of the casing that defines the developing chamber.

According to such a configuration, the bottom wall of the developer accommodating chamber is disposed at a position lower than the bottom wall of the developing chamber.

Therefore, the developer on the developing chamber side can easily return to the developer containing chamber side, and the adhesion of the developer to the blade can be reduced.
(6) The image forming apparatus further includes a supply member for supplying the developer to the developer carrying member, the separation portion is curved, and a tangent line of the separation portion at the tip of the separation portion is connected to the supply member. It may be configured not to intersect. Specifically, the tangent line of the separation portion at the tip of the separation portion may be configured to extend vertically above the supply member with a gap from the supply member.

According to such a configuration, the distal end of the separation portion faces the direction that does not intersect the supply member.

Therefore, even when the developer is scattered from the supply member, it is possible to reduce the developer from adhering to the blade.
(7) Moreover, the contact part may be arrange | positioned below the horizontal line which passes along the rotation center of a developing agent carrier.

According to such a configuration, the developer scraped off by the blade falls to the housing side without adhering to the surface of the developing roller.

Therefore, before the blade regulates the layer thickness of the developer with respect to the developer carrier, it is possible to suppress the excessive developer from being carried on the developer carrier.

As a result, it is possible to reduce the amount of developer that stays on the lower surface of the blade separation portion.
(8) The potential between the blade and the developer carrier may be configured to be substantially equal.

If there is a potential difference between the blade and the developer carrier, the charged developer tends to aggregate on the blade.

However, according to such a configuration, the charged developer can be prevented from aggregating on the blade.

According to the present invention, it is possible to reduce the accumulation and fixing of the developer on the blade, and to suppress the occurrence of printing defects.

FIG. 1 is a central sectional view of a printer as an example of an image forming apparatus. FIG. 2 is a perspective view of the developing cartridge shown in FIG. 1 viewed from the left rear side. FIG. 3 is a central sectional view of the developing cartridge shown in FIG. FIG. 4 is an enlarged view of FIG. FIG. 5 is an enlarged view corresponding to FIG. 4 showing a comparative example.

1. Overall Configuration of Printer As shown in FIG. 1, the printer 1 includes a main body casing 2 having a substantially box shape.

In addition, the printer 1 includes a paper feeding unit 3 for feeding the paper S and an image forming unit 4 for forming an image on the fed paper S in the main body casing 2.

Regarding the printer 1, when referring to the direction, the direction when it is placed in the horizontal direction is used as a reference, and specifically, the arrow direction shown in each drawing is used as a reference.
(1) Main Body Casing The main body casing 2 is formed with a cartridge opening 5 for attaching / detaching a process cartridge 15 (described later) and a paper opening 6 for introducing the paper S.

The cartridge opening 5 is formed through the upper end of the main casing 2 in the vertical direction.

The paper opening 6 is formed to penetrate in the front-rear direction at the lower end of the front end of the main casing 2.

Further, the main body casing 2 is provided with a top cover 7 at its upper end and a paper feed cover 8 at its front end.

The top cover 7 is provided to be swingable (movable) between a closed position for closing the cartridge opening 5 and an open position for opening the cartridge opening 5 with the rear end as a fulcrum.

The paper feed cover 8 is swingably (moved) between a first position where the paper opening 6 is closed and a second position where the paper opening 6 is opened with the lower end of the paper supply cover 8 as a fulcrum.
(2) Paper Feed Unit The paper feed unit 3 includes a paper placement unit 9 provided at the bottom of the main casing 2.

The paper stacking portion 9 is communicated with the outside of the main casing 2 through the paper opening 6.

The sheet S is stacked on the upper surface of the sheet feed cover 8 while the sheet feed cover 8 is disposed at the second position, and the rear part is loaded on the sheet via the sheet opening 6. Stacked in the placement unit 9.

The paper feeding unit 3 includes a pickup roller 11 disposed on the upper side of the rear end portion of the paper placing unit 9, a paper feeding roller 12 disposed on the rear side of the pickup roller 11, and a rear lower side of the paper feeding roller 12. The sheet feeding pad 13 is disposed opposite to the sheet feeding side, and the sheet feeding path 14 extends continuously upward from the rear end portion of the sheet feeding pad 13.
(3) Image Forming Unit The image forming unit 4 includes a process cartridge 15, a scanner unit 16, and a fixing unit 17.
(3-1) Process Cartridge The process cartridge 15 is configured to be detachable from the main casing 2 and is mounted on the main casing 2 above the rear portion of the paper feed unit 3.

The process cartridge 15 includes a drum cartridge 18 that is detachably attached to the main casing 2 and a developing cartridge 19 that is detachably attached to the drum cartridge 18.

The drum cartridge 18 includes a photosensitive drum 20, a transfer roller 21, and a scorotron charger 22.

The photosensitive drum 20 is formed in a cylindrical shape that is long in the left-right direction, and is provided rotatably at the rear portion of the drum cartridge 18.

The transfer roller 21 is formed in a substantially cylindrical shape extending in the left-right direction, and is rotatably provided at the rear portion of the drum cartridge 18 so as to be pressed against the photosensitive drum 20 from the rear side.

Specifically, the transfer roller 21 is disposed on the rear side of the photosensitive drum 20 so that the axial center thereof is positioned slightly below the axial center of the photosensitive drum 20. The lower end edge of the transfer roller 21 is disposed above the lower end edge of the photosensitive drum 20. Specifically, an imaginary line segment (not shown) connecting the axis center of the transfer roller 21 and the axis center of the photosensitive drum 20 and an imaginary straight line (not shown) extending horizontally along the front-rear direction are formed. The acute angle formed is about 3 °. Therefore, the pressure (transfer pressure) at which the transfer roller 21 is pressed against the photosensitive drum 20 is not affected by the weight of the transfer roller 21.

The scorotron charger 22 is disposed opposite to the front upper side of the photosensitive drum 20 with an interval.

Specifically, the scorotron charger 22 is disposed with a space in the circumferential direction of the photosensitive drum 20 with respect to the transfer roller 21, and is an imaginary link between the axial center of the photosensitive drum 20 and the axial center of the transfer roller 21. And an imaginary line segment (not shown) connecting the axial center of the photosensitive drum 20 and the charging wire 23 (described later) is about 120 °. Has been placed.

The scorotron charger 22 includes a charging wire 23 and a grid 24.

The charging wire 23 is stretched so as to extend in the left-right direction, and is opposed to the front upper side of the photosensitive drum 20 with an interval.

The grid 24 is formed in a substantially U shape in a side view opened toward the front upper side, and is provided so as to surround the charging wire 23 from the rear lower side.

The developing cartridge 19 is disposed on the lower front side of the photosensitive drum 20 and includes a developing frame 25 as an example of a housing.

In the developing frame 25, a toner accommodating chamber 26 and a developing chamber 27 as an example of a developer accommodating chamber are formed side by side. The toner storage chamber 26 and the developing chamber 27 are formed to have substantially the same volume, and communicate with each other through a communication port 28.

The toner storage chamber 26 stores toner as an example of a developer, and an agitator 29 as an example of a transport member is provided at a substantially central portion in the front-rear and vertical directions. That is, the agitator 29 is disposed below the photosensitive drum 20.

In the developing chamber 27, a supply roller groove wall 30, a developing roller facing wall 31, and a lower film attaching wall 32 are formed on the bottom wall 43.

The supply roller groove wall 30 has a substantially semicircular shape along the peripheral surface of the supply roller 33 (described later), and is formed so as to be recessed rearward and downward.

The developing roller facing wall 31 has a substantially arc shape along the peripheral surface of the developing roller 34 (described later), and is formed so as to extend rearward and upward continuously from the rear end portion of the supply roller groove wall 30.

The lower film attaching wall 32 is formed so as to continuously extend rearward from the rear end portion of the developing roller facing wall 31. That is, the lower film sticking wall 32 is disposed above the developing roller facing wall 31.

Further, the lower film adhering wall 32 is disposed to face the lower portion of the photosensitive drum 20 with an interval in the vertical direction, and overlaps the axial center of the photosensitive drum 20 when projected in the vertical direction. Is arranged.

Further, the developing chamber 27 is provided with a supply roller 33 as an example of a supply member, a development roller 34 as an example of a developer carrier, a layer thickness regulating blade 35, and a lower film 36.

The supply roller 33 is rotatably provided in the rear portion of the developing chamber 27 so that the lower portion thereof is disposed in the supply roller groove wall 30. Thus, the supply roller 33 is disposed on the rear side of the toner storage chamber 26 and is disposed at substantially the same height as the toner storage chamber 26 in the vertical direction (slightly above the toner storage chamber 26).

The developing roller 34 is rotatably provided in the rear portion of the developing chamber 27 so that the peripheral surface of the lower portion thereof and the developing roller facing wall 31 face each other with a space therebetween.

The developing roller 34 is provided so as to come into contact with the supply roller 33 from the upper rear side, and its upper and rear portions are exposed from the developing chamber 27, and contact the photosensitive drum 20 from the lower front side. Yes. That is, the developing roller 34 is disposed on the rear upper side of the supply roller 33 and on the front lower side of the photosensitive drum 20. The axial center of the supply roller 33, the axial center of the developing roller 34, and the axial center of the photosensitive drum 20 are located on substantially the same straight line along the radial direction of the photosensitive drum 20.

Further, the developing roller 34 is arranged with a space in the circumferential direction of the photosensitive drum 20 with respect to the scorotron charger 22, and a virtual line segment (which connects the axial center of the photosensitive drum 20 and the charging wire 23 ( (Not shown) and an imaginary line segment (not shown) connecting the axis center of the photosensitive drum 20 and the axis center of the developing roller 34 are arranged so that an angle of about 120 ° is formed. . That is, the developing roller 34, the scorotron charger 22, and the transfer roller 21 are arranged at substantially equal intervals in the circumferential direction of the photosensitive drum 20.

The upper end of the layer thickness regulating blade 35 is fixed to the rear upper end of the pair of left and right side walls of the developing chamber 27, and the lower end thereof is in contact with the developing roller 34 from the front side.

The rear portion of the lower film 36 is fixed to the lower film attaching wall 32, and the front end thereof is in contact with the peripheral surface of the developing roller 34 above the developing roller facing wall 31.
(3-2) Scanner Unit The scanner unit 16 is disposed on the front side of the process cartridge 15 so as to face the photosensitive drum 20 with a space in the front-rear direction.

The scanner unit 16 emits a laser beam L toward the photosensitive drum 20 based on the image data to expose the peripheral surface of the photosensitive drum 20.

Specifically, the laser beam L is emitted backward from the scanner unit 16 to expose the peripheral surface at the front end portion of the photosensitive drum 20. That is, the exposure point at which the photosensitive drum 20 is exposed (the peripheral surface at the front end portion of the photosensitive drum 20) is opposite to the nip point where the photosensitive drum 20 and the transfer roller 21 are in contact with the axial center of the photosensitive drum 20. Is set to

At this time, the developing cartridge 19 is arranged below the emission locus of the laser beam L, and the scorotron charger 22 is arranged above the emission locus of the laser beam L.

A guide portion 37 for guiding the attachment / detachment of the process cartridge 15 is provided on the inner side surface of the main body casing 2 between the scanner unit 16 and the photosensitive drum 20. When the process cartridge 15 is detached from the main casing 2, the process cartridge 15 is guided by the guide portion 37, so that the developing cartridge 19 attached to the drum cartridge 18 has a lower emission locus of the laser beam L. Pass from the top to the top.

At this time, the various rollers (transfer roller 21, supply roller 33 and developing roller 34) provided in the process cartridge 15 also pass the emission locus of the laser beam L from the lower side to the upper side.
(3-3) Fixing Unit The fixing unit 17 is disposed above the rear portion of the drum cartridge 18. Specifically, the fixing unit 17 includes a heating roller 38 disposed above the scorotron charger 22 and a pressure roller 39 pressed against the heating roller 38 from the rear upper side.

That is, the heating roller 38 is disposed in the vicinity of the upper end portion (open end portion) of the grid 24 of the scorotron charger 22.
(4) Image Forming Operation The toner in the toner storage chamber 26 of the developing cartridge 19 is supplied to the supply roller 33 through the communication port 28 by the rotation of the agitator 29, and further supplied to the developing roller 34. Between 33 and the developing roller 34, it is triboelectrically charged to the positive polarity.

The toner supplied to the developing roller 34 is regulated by the layer thickness regulating blade 35 as the developing roller 34 rotates, and is carried on the surface of the developing roller 34 as a thin layer having a constant thickness.

On the other hand, the surface of the photosensitive drum 20 is uniformly charged by the scorotron charger 22 and then exposed by the scanner unit 16. Thereby, an electrostatic latent image based on the image data is formed on the peripheral surface of the photosensitive drum 20. The toner carried on the developing roller 34 is supplied to the electrostatic latent image on the circumferential surface of the photosensitive drum 20, so that a toner image (developer image) is carried on the circumferential surface of the photosensitive drum 20.

The sheets S stacked on the sheet loading unit 9 are sent between the sheet feeding roller 12 and the sheet feeding pad 13 by the rotation of the pickup roller 11 and are turned one by one by the rotation of the sheet feeding roller 12. After that, the paper S that has been squeezed is conveyed to the paper feed path 14 by the rotation of the paper feed roller 12 and is fed sheet by sheet at a predetermined timing (photosensitive drum 20 (described later) and transfer roller 21 ( (To be described later).

Then, the sheet S is conveyed between the photosensitive drum 20 and the transfer roller 21 from the lower side to the upper side. At this time, the toner image is transferred onto the paper S to form an image.

The sheet S is heated and pressed when it passes between the heating roller 38 and the pressure roller 39. At this time, the image is thermally fixed on the paper S.

Thereafter, the paper S is conveyed toward the paper discharge roller 40, and is discharged onto a paper discharge tray 41 formed on the upper surface of the main casing 2 by the paper discharge roller 40.

In this way, the sheet S is fed from the sheet placing portion 9, passes between the photosensitive drum 20 and the transfer roller 21 (nip point), and then passes between the heating roller 38 and the pressure roller 39. After that, the paper is transported through a substantially C-shaped transport path in side view so that the paper is discharged onto the paper discharge tray 41.
2. Details of Developing Cartridge Next, the developing cartridge 19 will be described in detail.

In the description of the developing cartridge 19, when referring to the direction, the direction when the developing cartridge 19 is arranged horizontally is used as a reference, and specifically, the direction of the arrow shown in each drawing is used as a reference. That is, the up / down / front / rear direction with respect to the printer 1 and the up / down / front / rear direction with respect to the developing cartridge 19 are different from each other. Is attached to the printer 1 such that the front upper side and the lower side are the rear lower side of the printer 1.
(1) Development Frame As shown in FIGS. 2 and 3, the development frame 25 has a substantially box shape in which an opening extending in the left-right direction is formed on the rear side so that the rear portion of the development roller 34 is exposed. A pair of left and right side walls 42 that are formed in a substantially rectangular shape in side view, a bottom wall 43 that is laid between the lower ends of the pair of left and right side walls 42, and a pair of left and right side walls 42 and a front end portion of the bottom wall 43. And a pair of left and right side walls 42 and an upper wall 45 constructed between the upper ends of the front walls 44.

The pair of left and right side walls 42 are formed in a substantially flat plate shape extending in the front-rear direction, and are opposed to each other with an interval in the left-right direction.

A driving unit 100 for transmitting driving force to the supply roller 33 and the developing roller 34 is mounted on the left side surface of the left side wall 42, and the supply roller 33 and the developing roller 34 are connected to the outer side surface of the right side wall 42. A power supply unit 101 for applying a bias is mounted.

A pair of left and right blade fixing portions 46 projecting upward from the upper end edges of the pair of left and right side walls 42 are provided at the rear ends of the pair of left and right side walls 42.

The blade fixing portion 46 includes a pair of front and rear support plates 80 and a blade positioning boss 81 interposed between the pair of front and rear support plates 80.

The pair of front and rear support plates 80 are formed in a substantially rectangular flat plate shape extending in the vertical direction as viewed from the back, and are opposed to each other with an interval in the front-rear direction.

The blade positioning boss 81 is formed in a substantially cylindrical shape extending so as to penetrate the rear support plate 80.

The rear end portion of the blade positioning boss 81 has a length corresponding to the plate thickness of a support member 61 (described later) of the layer thickness regulating blade 35 and protrudes rearward from the rear side surface of the rear support plate 80.

As shown in FIG. 3, the bottom wall 43 includes the above-described supply roller groove wall 30, the developing roller facing wall 31, and the lower film attaching wall 32 in the rear portion, and an agitator sliding bottom in the front portion. A wall 47 and a partition wall 48 are provided.

The agitator sliding bottom wall 47 is formed in a substantially arc shape in cross section along the rotation locus of the agitator 29.

The partition wall 48 is continuous from the rear end of the agitator sliding bottom wall 47 (on the downstream side in the rotational direction of the agitator 29) in the front portion, along the tangential direction of the inner peripheral surface of the agitator sliding bottom wall 47. It is formed to extend linearly.

The partition wall 48 is continuous with the front end portion of the supply roller groove wall 30 at the rear end portion, and the side cross section projects upward by the rear end portion of the partition wall 48 and the front end portion of the supply roller groove wall 30. A V-shaped top 49 is formed.

The front wall 44 is formed so as to extend upward continuously from the front end portion of the bottom wall 43 (agitator sliding bottom wall 47). 50 is formed.

The upper wall 45 is constructed between the pair of left and right side walls 42 and the upper end of the front wall 44, and is formed to extend in the left-right direction.

The upper wall 45 includes a front portion 82 disposed on the front side of the upper wall 45, a rear portion 83 disposed on the rear lower side of the front portion 82, and a rear portion extending downward from the rear end portion of the front portion 82. 83, and a connecting portion 84 to which the front end portion of 83 is connected.

The front portion 82 is formed in a substantially rectangular shape in plan view extending in the left-right direction in the front portion of the upper wall 45, and a plurality of thin ribs extending in the left-right direction are provided on the upper side surface.

The rear portion 83 is arranged in parallel with the front portion 82 below the front portion 82 and is formed in a substantially rectangular shape in plan view extending in the left-right direction.

The rear portion 83 is provided with a first rib 87 and a second rib 88 extending in the left-right direction at a substantially center in the front-rear direction and a rear end portion of the rear portion 83.

The first ribs 87 are provided at substantially the center in the front-rear direction of the rear portion 83 so as to penetrate the thickness direction of the rear portion 83 and protrude above and below the rear portion 83.

The second rib 88 is provided at the rear end portion of the rear portion 83 so as to protrude in the vertical direction with respect to the rear portion 83.

A seal member 89 is attached to the rear side surface of the second rib 88.

The plane passing through the upper end surfaces of the first rib 87 and the second rib 88 is parallel to the upper surface of the front portion 82, and the total thickness of the support member 61 (described later) and the reinforcing member 62 (described later) of the layer thickness regulating blade 35 is totaled. Therefore, it is arranged at a position that is lower in the vertical direction than the upper surface of the front portion 82.

The connecting portion 84 is formed in a substantially rectangular shape in front view extending in the left-right direction, and is connected to the rear end portion of the front side portion 82 at the upper end portion thereof, and the front end portion of the rear side portion 83 is connected at substantially the center in the vertical direction. Has been.

The front surface of the lower end of the connecting portion 84 is formed so as to incline backward as it goes downward.

The toner storage chamber 26 for storing toner includes an agitator sliding bottom wall 47 and a partition wall 48, and a portion of the pair of left and right side walls 42 continuous to the agitator sliding bottom wall 47 and the partition wall 48; The upper wall 45 is partitioned by a portion facing the agitator sliding bottom wall 47 and the partition wall 48 and the front wall 44.

Further, the developing chamber 27 for accommodating the developing roller 34 includes a supply roller groove wall 30, a developing roller facing wall 31, a lower film attaching wall 32, and a pair of left and right side walls 42. A section that is continuous with the developing roller facing wall 31 and the lower film sticking wall 32 and a part of the upper wall 45 that faces the supply roller groove wall 30, the developing roller facing wall 31 and the lower film sticking wall 32. Has been.

The toner storage chamber 26 and the developing chamber 27 communicate with each other through a communication port 28 formed above the top 49 of the partition wall 48.

The toner storage chamber 26 is provided with an agitator 29 for conveying the toner to the developing roller 34 as described above.

The agitator 29 includes an agitator shaft 53 as an example of a rotating shaft and an agitator blade 54 as an example of a blade provided on the agitator shaft 53.

The both ends of the agitator shaft 53 are rotatably supported by the pair of left and right side walls 42 so as to be rotatable with respect to the developing frame 25.

The upper wall 45 faces the agitator shaft 53 from above, and a connecting portion 84 of the upper wall 45 projects toward the agitator shaft 53.

The agitator blade 54 is made of a flexible film such as polyethylene terephthalate (PET), has a substantially rectangular shape extending in the axial direction of the agitator shaft 53, and extends from the agitator shaft 53 toward the radially outer side. It is fixed to.

In the radial direction of the agitator shaft 53, the length from the agitator shaft 53 to the tip of the agitator blade 54 is the length from the agitator shaft 53 to the lower end portion of the connecting portion 84 of the upper wall 45, and from the agitator shaft 53 to the agitator slide. It is formed longer than the length to the moving bottom wall 47 and the partition wall 48.

In the developing chamber 27, as described above, the supply roller 33 for supplying the toner to the developing roller 34, the developing roller 34 for carrying the toner, and the thickness of the toner carried on the developing roller 34 are regulated. A layer thickness regulating blade 35 is provided.

The lower portion of the supply roller 33 is accommodated in the supply roller groove wall 30, so that the supply roller 33 is disposed close to the top 49 of the partition wall 48. And a sponge roller 56 made of a foam material.

The supply roller shaft 55 extends in the left-right direction and is rotatably supported by the pair of left and right side walls 42, whereby the supply roller 33 is provided so as to be rotatable with respect to the developing frame 25.

The sponge roller 56 covers the supply roller shaft 55 so that the left and right ends of the supply roller shaft 55 are exposed.

The developing roller 34 is disposed so as to face the developing roller facing wall 31 from above so that the upper portion of the developing roller 34 is exposed from the opening of the developing frame 25, and is made of a metal developing roller shaft 57 and a conductive rubber material. And a rubber roller 58.

The developing roller shaft 57 extends in the left-right direction and is rotatably supported by the pair of left and right side walls 42, whereby the developing roller 34 is rotatably provided with respect to the developing frame 25.

The rubber roller 58 covers the developing roller shaft 57 so that the left and right ends of the developing roller shaft 57 are exposed.

As described above, the developing roller 34 is in contact with the supply roller 33 from the upper rear side, and the sponge roller 56 and the rubber roller 58 are pressed against each other.
(2) Layer Thickness Restriction Blade The layer thickness restriction blade 35 is a blade member 60 as an example of a blade that contacts the developing roller 34, a support member 61 that supports the blade member 60, and a reinforcing member that reinforces the blade member 60. 62.

The blade member 60 is formed in a substantially rectangular flat plate shape extending in the left-right direction from a thin metal plate having elasticity.

The plate thickness (wall thickness) of the blade member 60 is set to 50 μm or more and 250 μm or less.

The lower end portion of the blade member 60 is bent in a circular arc forward over the entire width direction, as will be described in detail later.

As shown in FIG. 2, through holes 63 that penetrate the blade member 60 in the thickness direction (front-rear direction) are formed at both left and right ends of the upper end portion of the blade member 60.

The support member 61 is formed from a metal plate thicker than the blade member 60 or the like in a substantially L shape in a side sectional view (see FIG. 3). Specifically, the support member 61 includes a horizontal portion extending in the front-rear direction and a vertical portion extending downward from the rear end portion of the horizontal portion. A support member side screw hole 64 is formed in the horizontal portion of the support member 61, and the support member 61 includes a convex portion 65 and an attachment portion 66 in the vertical portion.

The four support member side screw holes 64 are formed at intervals in the left and right direction so as to penetrate the horizontal portion of the support member 61 in the thickness direction (up and down direction).

The convex portions 65 are formed in a substantially cylindrical shape that protrudes rearward from the rear side surface of the vertical portion of the support member 61 at both left and right ends of the support member 61.

The mounting portion 66 is formed in a substantially rectangular flat plate shape in front view protruding upward from the upper end portion of the vertical portion at both ends in the left-right direction of the support member 61. The attachment portion 66 is formed with an attachment hole (not shown) that penetrates the attachment portion 66 in the thickness direction (front-rear direction).

Similar to the support member 61, the reinforcing member 62 is formed in a substantially L shape in a side sectional view from a metal plate thicker than the blade member 60, and has a horizontal portion extending in the front-rear direction and a rear end portion of the horizontal portion And a vertical portion extending downward. A reinforcing member side screw hole 67 is formed in the horizontal portion of the reinforcing member 62.

The reinforcing member side screw holes 67 are arranged so as to correspond to the support member side screw holes 64, and are spaced apart from each other in the left-right direction so as to penetrate the horizontal portion of the reinforcing member 62 in the thickness direction (vertical direction). One is formed.

The blade member 60 is attached to the rear side surface of the vertical portion of the support member 61 so that the convex portion 65 of the support member 61 is inserted into the through hole 63 of the blade member 60 from the front.

Further, a reinforcing member 62 is combined with the supporting member 61 so as to cover the supporting member 61 from above. Specifically, the support member 61 and the reinforcing member 62 are combined such that horizontal portions thereof face each other in the vertical direction and vertical portions thereof face each other in the front-rear direction. Thus, the upper end portion of the blade member 60 is sandwiched between the vertical portion of the support member 61 and the vertical portion of the reinforcing member 62.

Further, the screw 68 is screwed into the support member side screw hole 64 and the reinforcing member side screw hole 67. Thus, the support member 61 and the reinforcing member 62 are fixed to each other with the blade member 60 being sandwiched (see FIG. 3), and the layer thickness regulating blade 35 is configured.

The layer thickness regulating blade 35 is attached to the pair of left and right blade fixing portions 46 of the pair of left and right side walls 42 in the pair of left and right attachment portions 66 of the support member 61. Specifically, the rear end portion of the blade positioning boss 81 of the blade fixing portion 46 is inserted into the mounting hole (not shown) of the mounting portion 66 from the front, and the screw 69 is screwed to the blade positioning boss 81. The layer thickness regulating blade 35 is fixed to the blade fixing portion 46 of the developing frame 25.

Further, as shown in FIG. 3, a seal member 89 is provided in the gap between the upper portion of the blade member 60 and the rear side surface of the vertical portion of the support member 61.

Accordingly, the state in which the upper portion of the blade member 60 is sandwiched between the support member 61 and the reinforcing member 62 is maintained, and the layer thickness regulating blade 35 is fixed to the developing frame 25. (3) Blade member The blade member 60 is partitioned between a base end portion 70 supported by the developing frame 25, a tip end portion 71 disposed on the developing roller 34 side, and the base end portion 70 and the tip end portion 71. And a straight line portion 72.

In the following description, the distal end surface of the distal end portion 71 is defined as a distal end A (see FIG. 4), and the boundary between the straight line portion 72 and the distal end portion 71 is defined as an inflection point B (see FIG. 4).

The base end portion 70 is partitioned into an upper end portion including the through hole 63 of the blade member 60, and the convex portion 65 of the support member 61 is inserted into the through hole 63 so as to be supported by the developing frame 25.

The straight line portion 72 is continuous with the lower end portion of the base end portion 70, is partitioned between the lower end portion of the base end portion 70 and the rear end portion of the tip end portion 71, and extends along the direction in which the base end portion 70 extends. It is formed in a flat plate shape that is substantially straight when viewed from the side.

The distal end portion 71 is continuous from the lower end portion of the linear portion 72 and is partitioned into lower end portions including the distal end A of the blade member 60. As shown in FIG. 4, the distal end portion 71 extends from the lower end portion (inflection point B) of the linear portion 72. It is formed to be bent in a circular arc shape toward the front with a predetermined radius of curvature toward A.

The radius of curvature of the tip 71 is set to 0.15 mm or more and 0.6 mm or less, and the central angle θ is set to 50 ° or more and 150 ° or less.

Further, the tip portion 71 includes a contact portion 73 that comes into contact with the peripheral surface of the rubber roller 58 of the developing roller 34, and a separation portion 74 that is separated from the surface of the rubber roller 58 toward the tip A from the contact portion 73.

The contact portion 73 is continuous from the lower end portion of the linear portion 72 and is disposed at a fixed position in the vertical direction with respect to the rubber roller 58 of the developing roller 34 as shown in FIG. As shown in FIG. 3, the contact portion 73 is pressed (contacted) from the front upper side by the elastic force of the blade member 60 over the entire left and right direction of the peripheral surface of the rubber roller 58.

The separating portion 74 is continuous from the contact portion 73 and is curved so as to be separated from the surface of the developing roller 34 from the contact portion 73 toward the tip A (see FIG. 4).

As shown in FIG. 3, the tangent line X of the separating portion 74 at the tip A of the separating portion 74 extends toward the front upper side while being spaced apart from the supply roller 33 on the lower side in the vertical direction. That is, the tangent line X of the separation portion 74 passing through the tip A of the separation portion 74 is set so as not to intersect the supply roller 33.

Therefore, when the layer thickness regulating blade 35 is viewed from the peripheral surface of the sponge roller 56 of the supply roller 33, the lower surface (outer peripheral surface) of the separating portion 74 is exposed and the upper surface (inner peripheral surface) of the separating portion 74 is hidden. Yes.
(4) Arrangement of Developer Cartridge in Main Body Casing The developer cartridge 19 is mounted on the drum cartridge 18 as described above. Thereby, the process cartridge 15 is formed.

The process cartridge 15 is mounted in the main casing 2 as shown in FIG.

Thus, in a state where the developing cartridge 19 is mounted in the main casing 2, the developing cartridge 19 has a rear side on the rear upper side of the main casing 2, a front side on the lower front side of the main casing 2, and an upper side on the main casing 2. The front upper side and the lower side of the main body casing 2 face the rear lower side. The lower end portion (deepest portion) of the inner side surface of the agitator sliding bottom wall 47 is disposed at a lower position in the vertical direction than the lower end portion (deepest portion) of the inner side surface of the supply roller groove wall 30.

Further, the lower portion of the connecting portion 84 of the upper wall 45 protrudes rearward and downward from the lower surface of the rear portion 83 of the upper wall 45.

Further, as shown in FIG. 4, the contact portion 73 of the blade member 60 is pressed (contacted) from the front lower side. The tip A of the separating portion 74 of the blade member 60 faces downward from the horizontal direction. The tangent line X of the separation portion 74 at the tip A of the separation portion 74 extends downward in the vertical direction while being spaced apart from the supply roller 33.

Further, the straight portion 72 of the blade member 60 is inclined forward as it goes upward. That is, with respect to the vertical line Y passing through the contact portion 73, the base end portion 70 is on the opposite side (front side with respect to the vertical line Y) of the rotation center of the developing roller 34 (the developing roller shaft 57 (see FIG. 1)). Has been placed.

Further, the tip 71 of the blade member 60 contacts the rubber roller 58 below the horizontal line Z passing through the developing roller shaft 57 of the developing roller 34, and the contact portion 73 is the rotation center of the developing roller 34 (developing roller shaft). 57 (see FIG. 1)).
4). When the image is formed, a driving force is input from a driving source (not shown) of the main casing 2 to the driving unit 100 of the developing cartridge 19, and a bias is supplied to the power supply unit 101 of the developing cartridge 19 from a power source (not shown) of the main casing 2. Is done.

The driving force from the driving unit 100 is transmitted to the agitator 29, and as shown in FIG. 1, the agitator 29 is driven to rotate clockwise about the agitator shaft 53 as a left side view.

Then, while stirring the toner, the agitator blade 54 first slides with the agitator sliding bottom wall 47, then slides with the partition wall 48, and then reaches the top 49 of the communication port 28.

At this time, the toner is conveyed from the communication port 28 toward the developing chamber 27 on the rear side.

When the agitator shaft 53 further rotates, the agitator blade 54 slides with the lower end portion of the connecting portion 84 of the upper wall 45 (see dotted line).

At this time, the toner storage chamber 26 is divided into a region C (rear side) on the upstream side in the rotational direction of the agitator shaft 53 and a region D (front side) on the downstream side by the agitator blade 54 and the connecting portion 84 (see FIG. 3).

As described above, the agitator blade 54 agitates the toner from the upstream side to the downstream side in the rotation direction of the agitator shaft 53 and abuts the connecting portion 84 while lifting the toner. The toner amount is relatively smaller than the area D partitioned on the downstream side.

Therefore, a part of the toner conveyed to the developing chamber 27 can easily return to the region C of the toner storage chamber 26.

Further, when the agitator shaft 53 rotates, the agitator blade 54 slides again with the agitator sliding bottom wall 47, the partition wall 48, and the connecting portion 84, and the above-described operation is repeated.

As the agitator 29 rotates, the toner is transported to the developing chamber 27, and then returns to the region C of the toner storing chamber 26 and circulates between the toner storing chamber 26 and the developing chamber 27.

The toner conveyed from the communication port 28 to the developing chamber 27 by the agitator 29 is supplied to the peripheral surface of the sponge roller 56 of the supply roller 33.

The driving force from the driving unit 100 is transmitted to the supply roller 33, and the supply bias from the power supply unit 101 is applied. Therefore, the supply roller 33 is driven to rotate counterclockwise as viewed from the left, with the supply roller shaft 55 as the center of rotation.

Then, the toner supplied from the agitator 29 is carried on the surface of the sponge roller 56. As the supply roller shaft 55 rotates, the toner carried on the sponge roller 56 is supplied to the peripheral surface of the rubber roller 58 of the developing roller 34.

At this time, toner may scatter from the peripheral surface of the sponge roller 56 of the supply roller 33 toward the downstream side in the rotation direction. However, such toner is blocked by the lower surface (outer peripheral surface) of the separation portion 74 and is prevented from reaching the upper surface (inner peripheral surface) of the separation portion 74.

The driving force from the driving unit 100 is transmitted to the developing roller 34, and the developing bias from the power supply unit 101 is applied. Therefore, the developing roller 34 is driven to rotate counterclockwise as viewed from the left, with the developing roller shaft 57 as the center of rotation.

At this time, since the blade member 60 is not connected to the power supply unit 101 and is not grounded, it floats in terms of potential. Therefore, the potential between the blade member 60 and the rubber roller 58 of the developing roller 34 is substantially equal.

Then, the toner supplied from the supply roller 33 is carried on the surface of the rubber roller 58.

The toner is triboelectrically charged to the positive polarity when passing through the pressure contact portion between the peripheral surface of the sponge roller 56 and the peripheral surface of the rubber roller 58.

As shown in FIG. 4, the toner carried on the peripheral surface of the rubber roller 58 of the developing roller 34 causes the tip 71 of the blade member 60 to move to the developing roller as the developing roller 34 rotates counterclockwise as viewed from the left side. 34 reaches the contact portion 73 that presses the circumferential surface of the rubber roller 58.

When the toner that has reached the contact portion 73 passes between the rear surface (outer peripheral surface) of the contact portion 73 and the peripheral surface of the rubber roller 58, it becomes a thin layer and is carried on the peripheral surface of the rubber roller 58.

The toner that could not pass between the rear surface of the contact portion 73 and the peripheral surface of the rubber roller 58 is scraped off by the rear surface of the contact portion 73.

As described above, the blade member 60 is in contact with the peripheral surface of the rubber roller 58 at the contact portion 73, thereby regulating the toner layer thickness on the peripheral surface of the rubber roller 58.

The toner scraped off is sandwiched between the region E upstream of the contact portion 73 in the rotation direction of the developing roller 34 (the lower surface of the separation portion 74 and the peripheral surface of the rubber roller 58 when viewed from the left-right direction). It stays so as to be dammed in the area that becomes narrower as it goes.

When the toner staying in the region E gradually increases, it adheres so as to ride on the upper surface (inner peripheral surface) of the separating portion 74 of the blade member 60 (see the dotted arrow T1).

However, when the developing cartridge 19 is mounted on the printer main body 2 as shown in FIG. 1, the tip A of the separating portion 74 of the blade member 60 faces downward as compared with the horizontal direction as shown in FIG. Such toner slides from the upper surface of the separation portion 74 (see the dotted arrow T2).

Further, the toner staying in the region E may be scattered on the front surface of the straight portion 72 of the blade member 60.

However, the linear portion 72 is inclined forward as it goes upward, and such toner slides down due to gravity.
5. Operational Effect (1) FIG. 5 shows a comparative example in which the printer 1 of the present embodiment is changed so that the tip A of the separating portion 74 of the blade member 60 faces upward from the horizontal direction Z as in the prior art. Show.

According to the comparative example, the toner in the region E that is scraped off by the contact portion 73 and stays on the lower surface of the separation portion 74 is upstream of the contact portion 73 in the rotation direction of the developing roller 34. If it rides on the upper surface of 74, it will accumulate | store on the upper surface of the separation part 74 (refer dotted line arrow T3).

Accumulated toner adheres to the upper surface of the separation portion 74. The fixed toner gradually grows and hangs down again from the upper surface of the separation portion 74 (see the dotted arrow T4).

In such a case, the toner that hangs down from the upper surface of the separation portion 74 comes into contact with the toner carried on the surface of the rubber roller 58, and a vertical streak-like printing defect in which an image is not partially formed occurs.

However, according to the printer 1 of the present embodiment, as shown in FIG. 4, the leading end A of the separating portion 74 faces downward from the horizontal direction.

Therefore, the toner in the area E that is scraped off by the contact portion 73 and stays on the lower surface of the separation portion 74 on the upstream side in the rotation direction of the developing roller 34 with respect to the contact portion 73 on the upper surface of the separation portion 74. Even if it rides, it slides down by gravity from the tip A of the separating portion 74.

As a result, it is possible to reduce the accumulation and fixing of toner on the upper surface of the separation portion 74, and it is possible to suppress the occurrence of printing defects.
(2) Further, in the comparative example, as shown in FIG. 5, the linear portion 72 defined between the base end portion 70 and the tip end portion 71 moves from the contact portion 73 toward the base end portion 70. With respect to the vertical line Y passing through 73, it is arranged so as to be inclined toward the same side as the rotation center of the developing roller 34 (developing roller shaft 57 (see FIG. 1)). That is, the front surface of the linear portion 72 is inclined backward as it goes upward.

However, according to the printer 1 of the present embodiment, as shown in FIG. 4, the base end portion 70 develops with respect to the vertical line Y passing through the contact portion 73 as it goes from the contact portion 73 to the base end portion 70. The roller 34 is disposed so as to incline toward the opposite side of the rotation center (the developing roller shaft 57 (see FIG. 1)). That is, the front surface of the linear portion 72 is inclined forward as it goes upward.

Therefore, even if the toner scatters and adheres to the front surface of the linear portion 72 defined between the proximal end portion 70 and the distal end portion 71 of the blade member 60, the toner slides down due to gravity.

As a result, the accumulation and fixing of toner on the front surface of the linear portion 72 can be reduced, and the occurrence of printing defects can be suppressed.
(3) Further, according to the printer 1 of the present embodiment, the agitator blade 54 of the agitator 29 abuts on the lower end portion of the connecting portion 84 of the upper wall 45 as shown by the dotted lines in FIG. 1 and FIG. The toner storage chamber 26 is partitioned into an upstream side and a downstream side in the rotational direction of the agitator shaft 53 with the agitator blade 54 and the connecting portion 84 as a boundary.

Since the agitator blade 54 abuts the lower end portion of the connecting portion 84 while lifting the toner, the region C partitioned on the upstream side has a relatively small amount of toner compared to the region D partitioned on the downstream side.

For this reason, the toner on the developing chamber 27 side easily returns to the region C. As a result, the adhesion of toner to the blade member 60 can be reduced.
(4) Further, according to the printer 1 of the present embodiment, the connecting portion 84 protrudes downward from the upper wall 45 disposed facing the upper side of the agitator shaft 53. Therefore, the agitator blade 54 reliably contacts the connecting portion 84. The upstream region C and the downstream region D in the rotational direction of the agitator shaft 53 are reliably partitioned by the agitator blade 54 and the connecting portion 84.

As a result, the toner on the developing chamber 27 side can easily return to the region C, and the adhesion of the toner to the blade member 60 can be reduced.
(5) Further, according to the printer 1 of the present embodiment, as shown in FIG. 1, the lower end portion (deepest portion) of the inner peripheral surface of the agitator sliding bottom wall 47 which is the bottom wall 43 in the toner storage chamber 26 is The developing chamber 27 is disposed at a lower position in the vertical direction than the lower end portion (deepest portion) of the inner peripheral surface of the supply roller groove wall 30 that is the bottom wall 43.

Therefore, the toner on the developing chamber 27 side can easily return to the toner containing chamber 26 side, and the adhesion of toner to the blade member 60 can be reduced.
(6) Further, as described above, the toner may be scattered from the sponge roller 56 of the supply roller 33 toward the downstream side in the rotation direction.

However, according to the printer 1 of the present embodiment, as shown in FIG. 3, the leading end A of the separating portion 74 faces the direction not intersecting with the supply roller 33. That is, the tangent line X of the separation portion 74 at the tip A of the separation portion 74 extends vertically above the supply roller 33 from the supply roller 33 with a gap. Therefore, when the layer thickness regulating blade 35 is viewed from the peripheral surface of the sponge roller 56 of the supply roller 33, the lower surface (outer peripheral surface) of the separating portion 74 is exposed and the upper surface (inner peripheral surface) of the separating portion 74 is hidden. Yes.

Therefore, such toner is blocked by the lower surface (outer peripheral surface) of the separation portion 74 and is prevented from reaching the upper surface (inner peripheral surface) of the separation portion 74.

As a result, it is possible to reduce the toner scattered in this way from adhering to the upper surface of the separation portion 74 of the blade member 60.
(7) Further, according to the printer 1 of the present embodiment, as shown in FIG. 4, the contact portion 73 of the blade member 60 is below the horizontal line Z passing through the developing roller shaft 57 of the developing roller 34, and the rubber roller 58 abuts. Therefore, the toner scraped off on the rear surface of the contact portion 73 does not adhere to the surface of the rubber roller 58 of the developing roller 34, and the sponge roller 56 (see FIG. 1) of the supply roller 33 on the lower side in the vertical direction of the contact portion 73. Fall on top).

Therefore, it is possible to suppress the excessive toner from being carried on the peripheral surface of the rubber roller 58 of the developing roller 34 on the upstream side of the contact portion 73 in the rotation direction of the developing roller 34.

As a result, the amount of toner in the region E staying so as to be dammed up on the lower surface of the separating portion 74 of the blade member 60 can be reduced.
(8) Also, according to the printer 1 of the present embodiment, the blade member 60 is floated in terms of potential, and there is no potential difference between the peripheral surface of the rubber roller 58 of the developing roller 34.

Therefore, the toner can be prevented from aggregating on the blade member 60.
6). Modification The printer 1 described above is an embodiment of the image forming apparatus of the present invention, and the present invention is not limited to the above-described embodiment.

The image forming apparatus of the present invention can be configured as a color printer in addition to a monochrome printer.

When the image forming apparatus is configured as a color printer, the image forming apparatus includes a direct tandem type color printer including a plurality of photosensitive members and a recording medium conveying member, a plurality of photosensitive members, an intermediate transfer member, and a transfer member. An intermediate transfer type tandem color printer can also be configured.

Further, the process cartridge 15 may be configured as an integral type integrally including the drum cartridge 18 and the developing cartridge 19 in addition to the separation type in which the drum cartridge 18 and the developing cartridge 19 are separated as described above.

Furthermore, the photosensitive drum 20 can be provided in the main casing 2 and only the developing cartridge 19 can be attached to and detached from the main casing 2.

Further, the developing cartridge 19 can be configured such that a toner cartridge that contains toner is detachably attached to a housing having a developer carrier.

Further, in place of the above-described photosensitive drum 20, for example, a photosensitive member such as a photosensitive belt can be applied.

Further, instead of the developing roller 34 described above, for example, a developer carrier such as a developing sleeve or a brush-like roller can be applied.

Further, instead of the supply roller 33 described above, for example, a supply member such as a supply sleeve, a supply belt, or a brush-like roller may be applied.

Further, instead of the agitator 29 described above, for example, a conveying member such as an auger screw or a conveying belt can be applied.

Further, in place of the transfer roller 21 described above, for example, a contact type transfer member such as a transfer belt, a transfer brush, or a transfer blade, or a non-contact type transfer member such as a corotron type can be applied. .

Further, in place of the above scorotron charger 22, for example, a non-contact charger such as a corotron charger or a charger provided with a sawtooth discharge member, or a contact charger such as a charging roller, for example. Etc. can be applied.

Further, instead of the scanner unit 16 described above, for example, an exposure member such as an LED unit can be applied.

Furthermore, the image forming apparatus of the present invention can also be configured as a multi-function machine equipped with an image reading unit and the like.

DESCRIPTION OF SYMBOLS 1 Printer 25 Developing frame 26 Toner accommodating chamber 27 Developing chamber 29 Agitator 33 Supply roller 34 Developing roller 43 Bottom wall 45 Upper wall 53 Agitator shaft 54 Agitator blade 60 Blade member 70 Base end portion 71 End portion 73 Contact portion 74 Spacing portion X Tangential line Y Vertical line Z Horizontal line

Claims (8)

A housing (25) for containing developer;
A developer carrying member (34) that is rotatable relative to the housing (25) and carries the developer;
A blade (60) for regulating the thickness of the developer carried on the developer carrying body (34),
The blade (60)
A proximal end (70) supported by the housing (25);
A tip (71) disposed on the developer carrier (34) side,
The tip (71) is
A contact portion (73) in contact with the peripheral surface of the developer carrier (34);
A separation portion (74) that is separated from the surface of the developer carrier (34) as it goes from the contact portion (73) to the tip,
The image forming apparatus (1) according to claim 1, wherein a tip of the separation portion (74) is directed downward from a horizontal direction. The base end (70) is disposed on the opposite side of the rotation center (57) of the developer carrier (34) with respect to the vertical line (Y) passing through the contact portion (73). The image forming apparatus (1) according to claim 1. A transport member (29) for transporting the developer to the developer carrier (34);
The conveying member (29)
A rotatable rotating shaft (53);
A blade (54) extending radially outward of the rotary shaft (53) from the rotary shaft (53),
The housing (25) includes an upper wall (45) facing the rotating shaft (53) from above,
The image forming apparatus (1) according to claim 1, wherein the blade (54) is configured to come into contact with the upper wall (45) when the rotating shaft (53) rotates. ). The image forming apparatus (1) according to claim 3, wherein the upper wall (45) partially protrudes downward (84) so as to contact the blade (54). In the case (25),
A developer accommodating chamber (26) for accommodating the developer;
A developer chamber (27) that communicates with the developer accommodating chamber (26) and accommodates the developer carrier (34);
The inner surface of the bottom wall (47) of the casing (25) that defines the developer accommodating chamber (26) is the bottom surface (30) of the casing (25) that defines the developing chamber (27). The image forming apparatus (1) according to any one of claims 1 to 4, wherein the image forming apparatus (1) is disposed at a lower position in the vertical direction than the inner surface. A supply member (33) for supplying the developer to the developer carrier (34);
The spacing part (74) is curved, and the tangent (X) of the spacing part (74) at the tip of the spacing part (74) does not intersect the supply member (33). Item 2. The image forming apparatus (1) according to Item 1. The image forming apparatus (1) according to claim 1, wherein the contact portion (73) is disposed below a horizontal line passing through a rotation center (57) of the developer carrier (34). ). The image forming apparatus (1) according to claim 1, wherein the potential difference between the blade (60) and the developer carrier (34) is substantially equal.

Images