JP5365506B2 - Developer cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing cartridge capable of largely changing circumferential speed of one of a first rotating body and a second rotating body without changing that of the other, and reducing degree of wear of a gear part for transmitting driving force to a first driving gear and a second driving gear. <P>SOLUTION: An input gear 70 is arranged on the outside of a side wall 36 on a left side in a developing housing 10. The input gear 70 has a large-diameter gear part 75 and a small-diameter gear part 76 in this order from the side of the side wall 36. A developing gear 71 and a supply gear 72 are respectively meshed with the large-diameter gear part 75 and the small-diameter gear part 76. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a developing cartridge that can be attached to and detached from an apparatus main body of an image forming apparatus.

2. Description of the Related Art An image forming apparatus such as a laser printer is known in which a developing cartridge is detachably attached to an apparatus main body.
The developing cartridge includes a developing roller and a supply roller for supplying toner to the developing roller. A gear mechanism for driving the developing roller and the supply roller is provided on one side wall of the developing cartridge. The gear mechanism includes an input gear to which driving force is input from the apparatus main body, a developing roller driving gear that is attached to an end of the developing roller shaft of the developing roller and meshes with the input gear, and a supply roller shaft of the supplying roller. A supply roller driving gear attached to the end and meshing with the input gear is provided. That is, the developing roller driving gear attached to the end of the developing roller shaft of the developing roller and the supply roller driving gear attached to the end of the supplying roller shaft of the supplying roller are an input gear to which driving force is input from the apparatus main body. Mesh with the same gear teeth.

  At the time of image formation, a driving force is input from the apparatus main body to the input gear, and the input gear is rotated. When the driving force is transmitted from the input gear to the developing roller driving gear and the supply roller driving gear, the developing roller is rotated through the developing roller driving gear, and the supplying roller is rotated through the supplying roller driving gear. Is done.

JP 2006-72284 A

  As described above, in the configuration in which the two rotating bodies (the developing roller and the supply roller) are rotationally driven by the driving force input to one input gear, the peripheral speed of one rotating body is reduced due to structural limitations. It may not be possible to change significantly. For example, when the distance between the axes of two rotating bodies and the peripheral speed of the other rotating body (first rotating body) cannot be changed, the peripheral speed of one rotating body (second rotating body) can be changed. However, there is no choice but to change the diameter of the gear connected to the second rotating body or the position of the input gear. However, since there is a space limitation on the arrangement of each gear, the gear diameter and the position of the input gear must be changed greatly. The peripheral speed of the second rotating body can be changed only slightly.

Further, since both the gear connected to the first rotating body and the gear connected to the second rotating body mesh with the input gear, the gear teeth of the input gear are likely to wear. If the gear teeth of the input gear are worn, the first rotating body and the second rotating body may not be stably driven.
An object of the present invention is to greatly change the other peripheral speed without changing one peripheral speed of the first rotating body and the second rotating body, and to the first driving gear and the second driving gear. It is an object of the present invention to provide a developing cartridge that can reduce the degree of wear of a gear portion that transmits a driving force.

  In order to achieve the above object, the present invention provides a developing cartridge that can be attached to and detached from an apparatus main body of an image forming apparatus, and is rotatable about an axis extending in a facing direction between the casing and both side walls of the casing. A first rotating body provided; a second rotating body having a shaft extending in the facing direction; a first driving gear coupled to the first rotating body; and a second driving gear attached to the shaft so as not to be relatively rotatable. A large-diameter gear portion that meshes with the first drive gear and a small-diameter gear portion that meshes with the second drive gear from the one side wall side. A driving force transmission gear for transmitting driving force to the first driving gear and the second driving gear, a bearing member that rotatably holds the shaft, the second driving gear, and the bearing member. And the second drive gear It is characterized in that it comprises a spacer for holding a position facing spaced outwardly against the large-diameter gear portion.

  According to the present invention, the developing cartridge includes the first rotating body and the second rotating body. The first rotating body is provided to be rotatable about an axis extending in the opposing direction of both side walls of the housing of the developing cartridge. A first drive gear is connected to the first rotating body. The second rotating body has an axis extending in the opposing direction of both side walls. A second drive gear is attached to the shaft so as not to be relatively rotatable.

  A driving force transmission gear is disposed on the outer side of one side wall in the opposite direction of the housing. The driving force transmission gear has a large-diameter gear portion and a small-diameter gear portion in this order from the one side wall side. The first drive gear and the second drive gear mesh with the large diameter gear portion and the small diameter gear portion, respectively. Thus, when a driving force is input to the driving force transmission gear, the driving force is transmitted to the first driving gear and the second driving gear via the large diameter gear portion and the small diameter gear portion. Unlike the configuration in which the first drive gear and the second drive gear mesh with one gear portion, the degree of wear of each gear tooth of the drive force transmission gear can be reduced.

Further, by changing the gear diameters of the large-diameter gear portion and the first drive gear, the peripheral speed of the first rotating body can be greatly changed without changing the peripheral speed of the second rotating body. Further, by changing the gear diameters of the small-diameter gear portion and the second drive gear, the peripheral speed of the second rotating body can be largely changed without changing the peripheral speed of the first rotating body.
The shaft is rotatably held by a bearing member. A spacer is interposed between the second drive gear and the bearing member. By this spacer, the second drive gear is held at a position facing the large-diameter gear portion so as to be spaced apart from the outside.

  Thereby, it can prevent reliably that the 2nd drive gear meshing | engaged with a small diameter gear part interferes with a large diameter gear part. In addition, since the large diameter gear portion can be arranged on the one side wall side, the diameter of the member for holding the driving force transmission gear in the housing can be increased to match the large diameter gear portion, and the driving force transmission The gear can be stably supported by the housing. Therefore, the peripheral speed of the other rotating body can be greatly changed without the second drive gear interfering with the large-diameter gear portion and without changing the peripheral speed of the one rotating body.

FIG. 1 is a side sectional view of a printer including a developing cartridge according to an embodiment of the present invention. FIG. 2 is a plan view of the developing cartridge. FIG. 3 is a left side view of the developing cartridge. FIG. 4 is a cross-sectional view of the developing cartridge taken along section line IV-IV shown in FIG. FIG. 5 is a left side view of the developing cartridge, showing a state in which the gear cover is removed. FIG. 6 is a left side view of the developing cartridge, and shows a state where the supply gear is removed from the state shown in FIG. FIG. 7 is a perspective view of the developing cartridge, showing a state where the gear cover is removed and the input gear and the supply bearing member are being attached.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1. Overall Configuration of Printer As shown in FIG. 1, a printer 1 as an example of an image forming apparatus includes a main body casing 2 as an example of an apparatus main body.
A process cartridge 3 is provided at the center of the main casing 2. The process cartridge 3 is detachably attached to the main body casing 2 via a front cover 4 provided on one side wall of the main body casing 2.

In the following description, the side of the main casing 2 where the front cover 4 is provided is the front side, and the opposite side is the rear side. In addition, when the printer 1 is viewed from the front side, the left and right reference is used. For the developing cartridge 32 to be described later, the state in which the developing cartridge 32 is mounted on the main casing 2 is used as a reference for front, rear, left and right.
The process cartridge 3 includes a drum cartridge 31 and a developing cartridge 32 that is detachably attached to the drum cartridge 31.

In the drum cartridge 31, the photosensitive drum 6 is rotatably provided. The drum cartridge 31 is provided with a charger 7 and a transfer roller 9.
The photosensitive drum 6 is provided to be rotatable around an axis extending in a direction perpendicular to the paper surface of FIG.
The charger 7 is a scorotron charger, and is disposed so as to face the circumferential surface of the photosensitive drum 6 with a space therebetween.

The developing cartridge 32 includes a developing housing 10 as an example of a housing that accommodates toner. Inside the developing case 10, a developing chamber 33 and a toner storage chamber 34 for storing toner to be supplied to the developing chamber 33 are formed adjacent to each other.
In the developing chamber 33, a developing roller 11 as an example of a first rotating body and a supply roller 37 as an example of a second rotating body are rotatably held.

A part of the peripheral surface of the developing roller 11 is exposed from the rear end portion of the developing housing 10. Further, the peripheral surface of the supply roller 37 is in contact with the front portion of the developing roller 11. The developing cartridge 32 is mounted on the drum cartridge 31 so that a portion of the developing roller 11 exposed from the developing housing 10 is in contact with the peripheral surface of the photosensitive drum 6.
An agitator 25 is rotatably held in the toner storage chamber 34. The toner in the toner storage chamber 34 is supplied into the developing chamber 33 while being stirred by the rotation of the agitator 25.

The transfer roller 9 is provided below the photosensitive drum 6 so as to be rotatable about an axis parallel to the rotational axis of the photosensitive drum 6, and is arranged so that the peripheral surface thereof is in contact with the peripheral surface of the photosensitive drum 6. .
In the main casing 2, an exposure unit 5 having a laser or the like is disposed above the process cartridge 3.

  At the time of image formation, the photosensitive drum 6 is rotated at a constant speed clockwise in FIG. As the photosensitive drum 6 rotates, the peripheral surface (surface) of the photosensitive drum 6 is uniformly charged by the discharge from the charger 7. On the other hand, a laser beam is emitted from the exposure unit 5 based on image data received from a personal computer (not shown) connected to the printer 1. The laser beam passes between the charger 7 and the developing cartridge 32 and is irradiated to the circumferential surface of the photosensitive drum 6 that is uniformly positively charged. As a result, the peripheral surface of the photosensitive drum 6 is selectively exposed, charges are selectively removed from the exposed portion, and an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 6. When the electrostatic latent image faces the developing roller 11 by the rotation of the photosensitive drum 6, toner is supplied from the developing roller 11 to the electrostatic latent image. As a result, a toner image is formed on the peripheral surface of the photosensitive drum 6.

A paper feed cassette 12 that accommodates the paper P is disposed at the bottom of the main casing 2. A pickup roller 13 for feeding paper from the paper feed cassette 12 is provided above the paper feed cassette 12.
Further, a conveying path 14 having an S-shape in side view is formed in the main body casing 2. This conveyance path 14 reaches from the paper feed cassette 12 to the paper discharge tray 15 formed on the upper surface of the main casing 2 via the space between the photosensitive drum 6 and the transfer roller 9. A separation roller 16 and a separation pad 17, a pair of paper feed rollers 18, a pair of registration rollers 19, and a pair of paper discharge rollers 20 are provided on the conveyance path 14 so as to face each other.

  The paper P sent out from the paper feed cassette 12 passes between the separation roller 16 and the separation pad 17, and at that time, is fed one by one. Thereafter, the paper P is conveyed toward the registration roller 19 by the paper supply roller 18. Then, after the registration by the registration roller 19, the sheet P is conveyed by the registration roller 19 toward the photosensitive drum 6 and the transfer roller 9.

The toner image on the circumferential surface of the photosensitive drum 6 is electrically attracted by the transfer roller 9 when the photosensitive drum 6 rotates and faces the paper P passing between the photosensitive drum 6 and the transfer roller 9. And transferred to the paper P.
A fixing device 21 is provided on the transport path 14 on the downstream side in the transport direction of the paper P with respect to the transfer roller 9. The paper P on which the toner image has been transferred is transported through the transport path 14 and passes through the fixing device 21. In the fixing device 21, the toner image becomes an image and is fixed on the paper P by heating and pressing.

The printer 1 has, as operation modes, a single-side mode in which an image (toner image) is formed on one side of the paper P, and an image formed on one side of the paper P and then on the other side opposite to the one side of the paper P. And a duplex mode for forming an image.
In the single-sided mode, the paper P on which an image is formed on one side is discharged to the paper discharge tray 15 by the paper discharge roller 20.

  As a configuration for realizing the double-sided mode, a reverse conveyance path 22 is formed in the main body casing 2. The reverse conveyance path 22 extends from the vicinity of the paper discharge roller 20 between the conveyance path 14 and the paper feed cassette 12, and is connected to a portion of the conveyance path 14 between the paper feed roller 18 and the registration roller 19. On the reverse conveyance path 22, a pair of first reverse conveyance rollers 23 and a pair of second reverse conveyance rollers 24 are provided.

In the double-sided mode, after an image is formed on one side of the paper P, the paper P is sent to the reverse conveyance path 22 without being discharged to the paper discharge tray 15. Then, the paper P is transported through the reverse transport path 22 by the first reverse transport roller 23 and the second reverse transport roller 24, the front and back are reversed, and the other surface on which the image is not formed is the periphery of the photosensitive drum 6. It is fed into the conveyance path 14 in a posture facing the surface. Then, an image is formed on both sides of the paper P by forming an image on the other side of the paper P.
2. Developing Cartridge The developing housing 10 of the developing cartridge 32 is formed in a box shape with the rear side opened.

  As shown in FIG. 2, the development housing 10 includes a pair of side walls 36 that face in the left-right direction. As shown in FIGS. 2 and 3, an upper wall 38 and a lower wall 39 are installed between the side walls 36. The upper wall 38 and the lower wall 39 are connected at the front end of the developing housing 10. The connecting portion is provided with a grip portion 40. The grip portion 40 extends from the front end portion of the developing housing 10 toward the front upper side, and is formed in a U-shaped cross section with the front side portion opened.

The developing roller 11 and the supply roller 37 (see FIG. 1) are rotatably held between the side walls 36.
(1) Developing Roller As shown in FIGS. 2 and 3, the developing roller 11 is disposed between the rear ends of the side walls 36. As shown in FIG. 4, the developing roller 11 includes a cylindrical developing roller main body 45 extending in the left-right direction, and a developing roller shaft 46 extending along the central axis of the developing roller main body 45.

Both end portions of the developing roller shaft 46 penetrate both side walls 36 of the developing housing 10.
(2) Supply Roller As shown in FIG. 1, the supply roller 37 is disposed at a lower position on the front side with respect to the developing roller 11. As shown in FIG. 4, the supply roller 37 includes a cylindrical supply roller main body 47 extending in the left-right direction, and a supply roller shaft 48 as an example of an axis extending along the central axis of the supply roller main body 47. .

The peripheral surface of the supply roller main body 47 is in contact with the peripheral surface of the developing roller main body 45 from the lower front side.
Both end portions of the supply roller shaft 48 penetrate both side walls 36 of the developing housing 10.
(3) Bearing Member As shown in FIG. 4, a right bearing member 50 is provided outside the right side wall 36. The right end portions of the developing roller shaft 46 and the supply roller shaft 48 are supported by the right side wall 36 through the right bearing member 50 so as to be relatively rotatable. That is, the right bearing member 50 collectively holds the right end portion of the developing roller shaft 46 and the right end portion of the supply roller shaft 48.

A developing bearing member 51 and a supply bearing member 52 as an example of a bearing member are provided outside the left side wall 36.
The development bearing member 51 is formed in a cylindrical shape and is attached to the left side wall 36 so as not to be relatively rotatable. The developing roller shaft 46 is inserted inside the developing bearing member 51. Thereby, the left end portion of the developing roller shaft 46 is supported by the left side wall 36 via the developing bearing member 51 so as to be relatively rotatable.

The supply bearing member 52 is integrally provided with a locking portion 53, a flange portion 54, and a spacer 55 as an example of a cylindrical portion.
The locking portion 53 is formed in a substantially cylindrical shape and is attached to the left side wall 36 so as not to be relatively rotatable. A hook-like portion 56 that is bent so as to approach the supply roller shaft 48 is formed at the right end portion of the locking portion 53. The supply roller shaft 48 is formed with a locked groove 57 cut out from the peripheral surface along the circumferential direction at a position facing the flanged portion 56. When the hook-like portion 56 enters the locked groove 57, the supply roller shaft 48 is positioned in the axial direction (left-right direction).

As shown in FIGS. 6 and 7, the flange portion 54 is formed in a substantially square shape. The flange portion 54 is in contact with the left side wall 36 from the left side.
The spacer 55 is formed in a cylindrical shape extending in the left-right direction. A supply roller shaft 48 is inserted inside the spacer 55.
Thereby, the left end portion of the supply roller shaft 48 is supported by the left side wall 36 through the supply bearing member 52 so as not to be relatively rotatable.
(4) Gear Mechanism As shown in FIGS. 2 to 4, a gear cover 42 is attached to the left end portion of the developing cartridge 32.
(4-1) Gear Cover The gear cover 42 is integrally provided with a side plate 60 that faces the left side wall 36 from the left side, and a peripheral plate 61 that extends from the periphery of the side plate 60 toward the developing housing 10.

As shown in FIG. 3, the side plate 60 has a plate shape extending in the front-rear direction and the up-down direction, and is formed to have a size facing almost the entire region of the developing chamber 33 and the toner storage chamber 34 (see FIG. 1).
As shown in FIGS. 3 and 4, the left end portion of the developing roller shaft 46 protrudes leftward from the gear cover 42, and a cylindrical collar member 62 is attached to the protruding portion.

Further, two screw holes (not shown) are formed in the front end portion and the rear end portion of the side plate 60. The screws 65 are screwed onto the left side wall 36 through these screw holes, whereby the side plate 60 is fixed to the left side wall 36 (developing housing 10).
A coupling insertion portion 66 is formed at a position above the front side with respect to the collar member 62. The coupling insertion part 66 has a cylindrical shape protruding leftward. A coupling member 77 described later is inserted into the coupling insertion portion 66 so as to be relatively rotatable.
(4-2) Gear As shown in FIG. 5, on the outside of the left side plate 36, there are an input gear 70 as an example of a drive transmission gear, a developing gear 71 as an example of a first drive gear, and a second drive gear. As an example, a supply gear 72, a connection gear 73, and an agitator gear 74 are provided. Each of the gears 70 to 74 is provided to be rotatable around a rotation axis along the left-right direction.
(4-2-1) Input Gear As shown in FIGS. 5 and 6, the input gear 70 is disposed on the upper side of the front end portion of the developing housing 10. The input gear 70 is supported on the left side wall 36 so as to be relatively rotatable. As shown in FIGS. 5 to 7, the input gear 70 is integrally provided with a large diameter gear portion 75, a small diameter gear portion 76 and a coupling member 77. The large-diameter gear portion 75, the small-diameter gear portion 76, and the coupling member 77 are arranged in this order from the side wall 36 side.

Gear teeth are formed on the peripheral surfaces of the large diameter gear portion 75 and the small diameter gear portion 76.
As shown in FIG. 6, the large-diameter gear portion 75 faces the spacer 55 of the supply bearing member 52 from above. Therefore, the spacer 55 is formed with a cutout portion 95 having a shape cut off from the peripheral surface at a portion facing the large-diameter gear portion 75. Thereby, the contact with the spacer 55 and the large diameter gear part 75 is avoided.

The small diameter gear portion 76 is formed to have a smaller diameter than the large diameter gear portion 75.
As shown in FIGS. 5 and 6, a coupling portion 80 is formed on the left side surface of the coupling member 77. The coupling portion 80 is formed by digging rightward from the left side surface of the coupling member 77, and has a shape in which a part of a circle is partially cut out in a fan shape from the periphery.
(4-2-2) Developing Gear The developing gear 71 is disposed at a position below the rear side with respect to the input gear 70. The developing gear 71 is attached to the developing roller shaft 46 so as not to be relatively rotatable. The left end portion of the developing roller shaft 46 protrudes leftward from the developing gear 71. And the protrusion 81 is attached with a C-shaped stopper 81 in a side view. Thereby, the movement of the developing roller 71 in the axial direction (left-right direction) of the developing roller shaft 46 is restricted.

The developing gear 71 meshes with the large diameter gear portion 75 of the input gear 70.
Further, as shown in FIG. 6, the developing gear 71 faces the flange portion 54 of the supply bearing member 52 from the upper rear side. Therefore, the flange portion 54 is formed with a notch 96 having a shape notched from the peripheral edge at a portion facing the developing gear 71. As a result, contact between the flange 54 (supply bearing member 52) and the developing gear 71 is avoided.
(4-2-3) Supply Gear As shown in FIG. 5, the supply gear 72 is disposed at a position below the input gear 70. As shown in FIG. 4, the supply gear 72 is attached around the supply roller shaft 48 so as not to rotate relative to the outside of the spacer 55 of the supply bearing member 52. Specifically, the left end portion of the supply roller shaft 48 is D-cut processed into a D-shaped cross-section with a part of its peripheral surface cut off. Then, by inserting the D-shaped portion into the supply gear 72, the supply gear 72 is attached to the supply roller shaft 48 so as not to be relatively rotatable. The left end portion of the supply roller shaft 48 is disposed on the inner side (right side) than the left end surface of the supply gear 72 while being inserted into the supply gear 72.

As shown in FIG. 5, the supply gear 72 meshes with the small diameter gear portion 76 of the input gear 70. Further, the peripheral edge portion of the supply gear 72 is opposed to the large-diameter gear portion 75 of the input gear 70 while being spaced apart on the left side.
(4-2-4) Connection Gear As shown in FIGS. 5 and 6, the connection gear 73 is disposed at a position in front of the input gear 70. The connecting gear 73 is integrally provided with a first gear portion (not shown) having gear teeth on the peripheral surface and a second gear portion 86. The first gear portion has a smaller diameter than the second gear portion 86 and is disposed on the side wall 36 side with respect to the second gear portion 86.

The connection gear 73 is supported on the left side wall 36 so as to be relatively rotatable.
The second gear portion 86 meshes with the small diameter gear portion 76 of the input gear 70.
(4-2-5) Agitator Gear The agitator gear 74 is disposed at a position below the front side with respect to the connecting gear 73. The agitator gear 74 is integrally provided with a support portion 88 and a gear portion 89.

  The support part 88 is formed in a cylindrical shape. A shaft insertion hole 90 having a D-shaped cross section is formed in the center of the support portion 88 so as to penetrate in the axial direction. The agitator shaft 91 is inserted into the shaft insertion hole 90 so as not to be relatively rotatable. Specifically, the left end portion of the agitator shaft 91 is D-cut processed into a D-shaped cross-section with a part of its peripheral surface cut off. Then, by inserting the D-shaped portion into the shaft insertion hole 90, the agitator gear 74 is attached to the agitator shaft 91 so as not to be relatively rotatable. The agitator shaft 91 is connected to the agitator 25 shown in FIG. Accordingly, when the agitator gear 74 rotates, the agitator 25 rotates via the agitator shaft 91.

The gear part 89 meshes with the first gear part 85 of the connection gear 73.
4). Configuration in Main Body Casing As shown by phantom lines in FIG. 2, a main body side coupling 99 as an example of a drive member is provided in the main body casing 2. The main body side coupling 99 is disposed at a position facing the coupling member 77 (see FIG. 7) from the left in a state where the developing cartridge 32 is mounted on the main body casing 2 (see FIG. 1). The main body side coupling 99 has an engagement protrusion (not shown) protruding rightward.

  After the mounting of the developing cartridge 32 into the main body casing 2 is completed, when the main body side coupling 99 is advanced to the right, the engaging protrusion of the main body side coupling 99 is connected to the coupling portion 80 of the coupling member 77 (see FIG. 7)). When the main body side coupling 99 is further advanced to the right, the coupling member 77 is pressed to the right. Thereby, the positioning of the input gear 70 in the left-right direction is achieved. Thereafter, when a rotational driving force from a motor (not shown) is input to the main body side coupling 99, the coupling member 77 rotates via the main body side coupling 99.

The advancement of the main body side coupling 99 to the right can be interlocked with the closing operation of the front cover 4 shown in FIG. Since such an interlocking operation is well known, detailed description of the interlocking mechanism is omitted.
5. Gear Driving When the main body side coupling 99 is connected to the coupling member 77 and a rotational driving force is input to the input gear 70, the input gear 70 rotates in the clockwise direction in FIG.

The developing gear 71 is engaged with the large-diameter gear portion 75 of the input gear 70. Therefore, the developing gear 71 rotates counterclockwise in FIG. 5 as the input gear 70 rotates. As a result, the developing roller 11 (see FIG. 1) rotates counterclockwise in FIG. 1 via the developing gear 71.
As shown in FIG. 5, the supply gear 72 meshes with the small diameter gear portion 76 of the input gear 70. Therefore, the supply gear 72 rotates counterclockwise in FIG. 5 as the input gear 70 rotates. Accordingly, the supply roller 37 (see FIG. 1) rotates counterclockwise in FIG. 1 via the supply gear 72.

Since the gear diameter of the small diameter gear portion 76 is smaller than that of the large diameter gear portion 75, the rotation speed of the supply gear portion 72 that meshes with the small diameter gear portion 76 is higher than the rotation speed of the developing gear 71 that meshes with the large diameter gear portion 75. Get smaller. Therefore, the peripheral speed of the supply roller 37 (see FIG. 1) is smaller than the peripheral speed of the developing roller 11.
Further, the second gear portion 86 of the connecting gear 73 is engaged with the small diameter gear portion 76 of the input gear 70. Therefore, the connection gear 73 rotates in the counterclockwise direction in FIG. 5 as the input gear 70 rotates.

The gear portion 89 of the agitator gear 74 meshes with the first gear portion 85 of the connection gear 73. Therefore, the agitator gear 74 rotates in the clockwise direction in FIG. 5 as the connecting gear 73 rotates. As a result, the agitator 25 (see FIG. 1) rotates in the clockwise direction in FIG. 1 via the agitator gear 74.
6). As described above, the developing cartridge 32 includes the developing roller 11 and the supply roller 37. The developing roller 11 is rotatably provided around a developing roller shaft 46 extending in the left-right direction. A developing gear 71 is connected to the developing roller 11. The supply roller 37 has a supply roller shaft 48 extending in the left-right direction. A supply gear 72 is attached to the supply roller shaft 48 so as not to be relatively rotatable.

  An input gear 70 is disposed outside the left side wall 36 in the developing housing 10. The input gear 70 has a large-diameter gear portion 75 and a small-diameter gear portion 76 in this order from the side wall 36 side. A developing gear 71 and a supply gear 72 are engaged with the large diameter gear portion 75 and the small diameter gear portion 76, respectively. Thus, when a driving force is input to the input gear 70, the driving force is transmitted to the developing gear 71 and the supply gear 72 via the large diameter gear portion 75 and the small diameter gear portion 76. Unlike the configuration in which the developing gear 71 and the supply gear 72 mesh with one gear portion, the degree of wear of the gear teeth 75 and 76 of the input gear 70 can be reduced.

  Further, by changing the gear diameters of the large-diameter gear portion 75 and the developing gear 71, the peripheral speed of the developing roller 11 can be largely changed without changing the peripheral speed of the supply roller 37. Further, by changing the gear diameters of the small diameter gear portion 76 and the supply gear 72, the peripheral speed of the supply roller 37 can be greatly changed without changing the peripheral speed of the developing roller 11.

The supply roller shaft 48 is rotatably held by a supply bearing member 52. A spacer 55 is interposed between the supply gear 72 and the supply bearing member 52. By the spacer 55, the supply gear 72 is held at a position facing the large-diameter gear portion 75 so as to be spaced apart from the outside.
Thereby, it is possible to reliably prevent the supply gear 72 meshing with the small diameter gear portion 76 from interfering with the large diameter gear portion 75. Further, since the large-diameter gear portion 75 can be disposed on the side wall 36 side, the diameter of a member for holding the input gear 70 on the developing housing 10 can be increased according to the large-diameter gear portion 75, The input gear 70 can be stably supported on the developing housing 10. Therefore, the peripheral speed of the supply roller 37 (developing roller 11) is greatly changed without changing the peripheral speed of the developing roller 11 (supply roller 37) without the supply gear 72 interfering with the large-diameter gear portion 75. Can do.

Further, since the supply gear 72 connected to the supply roller shaft 48 meshes with the small-diameter gear portion 76 of the input gear 70, the peripheral speed of the supply roller 37 can be made smaller than that of the developing roller 11. Thereby, friction generated between the developing roller 11 and the supply roller 37 can be reduced, and toner deterioration due to the friction can be suppressed.
The spacer 55 is formed in a shape that avoids contact with the input gear 70. Thereby, since the space | interval of the spacer 55 and the input gear 70 can be made small, the space | interval of the supply gear 72 hold | maintained at the spacer 55 and the input gear 70 can be made small. Therefore, the space for disposing the supply gear 72 and the input gear 70 can be reduced, and the development cartridge 32 can be downsized.

Further, the supply roller shaft 48 is inserted into the spacer 55. A cutout portion 95 is formed on the outer peripheral surface of the spacer 55 at a portion facing the input gear 70 in a side view. Thereby, the spacer 55 can be formed in a shape that avoids the input gear 70.
The spacer 55 is formed integrally with the supply bearing member 52. This eliminates the trouble of attaching the spacer 55 between the supply bearing member 52 and the supply gear 72, thereby simplifying the manufacturing process of the developing cartridge 32.

A main body side coupling 99 is coupled to the coupling portion 80 of the input gear 70 from the left side. Accordingly, a driving force can be transmitted from the main body side coupling 99 to the input gear 70, and the driving force is transmitted to the developing roller 11 via the developing gear 71 and to the supplying roller 37 via the supplying gear 72. Can communicate.
7). Modifications Although one embodiment of the present invention has been described above, the present invention can be implemented in other forms.

  For example, in the above embodiment, a monochrome printer is illustrated as an example of the image forming apparatus, but a color printer may be employed as an example of the image forming apparatus. In this case, the present invention can be applied to a developing cartridge that is detachably attached to a color printer.

DESCRIPTION OF SYMBOLS 1 Printer 2 Main body casing 10 Developing housing 11 Developing roller 32 Developing cartridge 36 Side wall 37 Supply roller 48 Supply roller shaft 52 Supply bearing member 55 Spacer 70 Input gear 71 Development gear 72 Supply gear 75 Large diameter gear portion 76 Small diameter gear portion 80 Coupling Part 99 Body side coupling

Claims (4)

A developing cartridge that can be attached to and detached from the main body of the image forming apparatus,
A housing,
A first rotating body provided rotatably about an axis extending in the opposing direction of both side walls of the housing;
A second rotating body having an axis extending in the facing direction;
A first drive gear coupled to the first rotating body;
A second drive gear attached to the shaft in a relatively non-rotatable manner;
A large-diameter gear portion that meshes with the first drive gear and a small-diameter gear portion that meshes with the second drive gear are arranged in this order from the one side wall side. A driving force transmission gear for transmitting a driving force to the first driving gear and the second driving gear;
A bearing member for rotatably holding the shaft;
A spacer that is interposed between the second drive gear and the bearing member, and holds the second drive gear at a position facing the large-diameter gear portion so as to be spaced apart from the outside .
The spacer is
Formed in a shape avoiding contact with the driving force transmission gear,
A cylindrical portion through which the shaft is inserted;
The developing cartridge , wherein an outer peripheral surface of the cylindrical portion is formed in a shape in which a portion facing the driving force transmission gear is cut off when viewed from a direction along a central axis thereof . The first rotating body is a developing roller;
The developing cartridge according to claim 1, wherein the second rotating body is a supply roller for supplying a developer to the developing roller. The spacer, the bearing member and are integrally formed, the developing cartridge according to claim 1 or 2. The driving force transmission gear, the coupling portion is driven member for inputting a drive force from the outside is coupled in the opposite direction is formed, a developing cartridge according to any one of claims 1 to 3 .

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