JP2010026541A - Developing cartridge and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing cartridge that can continuously maintain a preferable pressing condition to press a developer carrier against an image carrier, and to provide an image forming apparatus equipped with the developing cartridge. <P>SOLUTION: The developing cartridge 27 may include a handle 214. A coil spring 218 is disposed, in a compressed state between the underside of the handle 214 and a contacting member 217. As a result, each time the developing cartridge 27 is replaced, a new coil spring 218 and handle 214 can be provided for a color laser printer, with the developing cartridge 27 attached. Accordingly, a constant pressure by the coil spring 218 can be maintained continuously, and the preferable pressure condition of the developer carrier 39 with respect to the photoreceptor drum 29 can be maintained continuously. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, a so-called tandem type image forming apparatus is known in which photosensitive members corresponding to yellow, magenta, cyan, and black are arranged in parallel in the horizontal direction. In this tandem type image forming apparatus, each color toner image is formed almost simultaneously on each photoconductor, and the toner images of each color are sequentially superimposed and transferred from the respective photoconductors to paper that sequentially passes through each photoconductor. Therefore, it is possible to form a color image at almost the same speed as the monochrome image forming apparatus.

  As such a tandem type image forming apparatus, there has been proposed an apparatus in which a developing cartridge for developing an electrostatic latent image formed on a photoreceptor into a toner image is detachable from the apparatus main body. For example, Patent Document 1 includes a photoconductor cartridge having a structure in which photoconductors of respective colors are integrally supported by a frame, and the photoconductor cartridge is provided to be slidable with respect to the apparatus main body by being slidable. Has been proposed that is detachable from the photosensitive cartridge.

  The developing cartridge is provided with a developing roller for supplying toner to the photoreceptor. The apparatus main body is provided with an elastic member such as a spring. When the developing cartridge is mounted on the apparatus main body, the developing cartridge is urged by the elastic member, and the developing roller is fixed to the photosensitive member. Pressed with pressing force.

JP 2003-15378 A

However, the biasing force with which the elastic member biases the developing cartridge gradually decreases as the elastic member deteriorates. When the urging force of the elastic member is reduced, the pressing force of the developing roller against the photosensitive member is reduced, and there is a risk of developing failure due to insufficient supply of toner.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing cartridge that can keep a good pressing state of a developer carrying member against an image carrying member and an image forming apparatus including the developing cartridge.

  In order to achieve the above object, according to the first aspect of the present invention, in the developing cartridge, a developer is supplied to an image carrier on which an electrostatic latent image is formed to visualize the electrostatic latent image. A developer carrying member for housing the developer, a housing that contains the developer and that supports the developer carrying member at one end, and the developer carrying member in the housing The other end of the developer carrier opposite to the support portion is provided so as to be rotatable about a rotation axis that extends in the axial direction of the developer carrier, and is located outside the housing in the axial direction of the developer carrier. Two protrusions projecting inwardly, and provided with a gap in the axial direction on the inner side in the axial direction than the side surface in the axial direction of the casing. When a pressing force is input to the protrusion, the developer carrier is pressed against the image carrier. A biasing portion that biases the housing in a direction in which the developer carrier is rotated by the pressing force, and the developer carrier is pressed against the image carrier via the biasing portion. And a pressing member that presses the housing.

According to such a configuration, since the pressing member is provided in the developing cartridge, a new pressing member can be provided in the image forming apparatus to which the developing cartridge is mounted every time the developing cartridge is replaced. Therefore, the force by which the pressing member urges the housing can be kept constant, and the developer carrier can be kept in a good pressing state with respect to the image carrier. In the invention according to claim 1, the pressing member also serves as a handle to be gripped when the developing cartridge is moved.

  According to such a configuration, since the handle is provided, the developing device can be moved by gripping the handle. In addition, since the pressing member also serves as a handle, the pressing member is rotatable, so that it is rotated in the opening direction when used as a handle, and is rotated in the closing direction when acting as a pressing member. Can do. Moreover, the number of parts can be reduced as compared with the configuration in which the pressing member and the handle are provided separately. Therefore, the number of parts can be reduced while the operability of the developing cartridge can be improved.

The invention according to claim 3 is the invention according to claim 1 or 2, further comprising a guide member provided on the pressing member for guiding elastic deformation of the urging portion due to the pressing force. It is said.
According to such a configuration, the elastic deformation of the urging portion is guided by the guide member. Therefore, when a pressing force is input to the urging unit, the urging unit can be elastically deformed while keeping the posture of the urging unit stable. As a result, the developer carrying member can be reliably urged toward the image carrying member.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the urging portion generates an urging force of 1N or more and 20N or less.
According to such a configuration, if the urging force of the urging unit is 1 N or more, it is possible to prevent the developer carrying member from hitting the image carrying member due to insufficient urging force. Further, when the urging force of the urging unit is 20 N or less, the urging force is not excessively large, and it is possible to prevent the so-called press fogging in which the developer adheres to an undesired region of the image carrier.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the developing cartridge is used in a color image forming apparatus including a plurality of the image carriers provided corresponding to the respective colors. It is characterized by that.
According to such a configuration, it is possible to set an appropriate urging force according to the type (color) of the developer contained in the housing for each developing cartridge, and the developer carrying member is imaged by the urging force. The carrier can be pressed well. Therefore, it is possible to satisfactorily supply a developer of a color corresponding to each image carrier.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, in the color image forming apparatus, the one end of the casing is positioned relatively downward in the developing cartridge. The other end of the body is disposed so as to be relatively positioned above.
In such a configuration, the weight of the developing cartridge acts on the pressing of the developer carrying member against the image carrying member. Therefore, when the developer amount stored in the housing and the design of the housing are changed, and the weight of the developing cartridge changes, the pressing state of the developer carrying body against the image carrier changes. Since the developing cartridge is provided with a pressing member, even if the weight of the developing cartridge is changed, the developer carrying member is kept in a predetermined pressing state against the image carrying member by adjusting the urging force of the urging unit. Can be pressed.

  According to a seventh aspect of the present invention, in the invention according to the fifth or sixth aspect, the color image forming apparatus is detachably attached to the apparatus main body and the apparatus main body, and a plurality of the image carriers are arranged. An image carrier unit that is integrally held, the developer cartridge is detachably attached to the image carrier unit, and the pressing member is attached to the image carrier unit by the developing member. In a state where the image carrier unit is mounted, an upright state extending in a direction intersecting with the attaching / detaching direction of the image carrier unit and an upstream side in the moving direction when the image carrier unit is mounted, with the standing state intersecting with the attaching / detaching direction. It is characterized by being provided so as to be able to rotate in a tilted state in which it tilts.

  According to such a configuration, since the pressing member is rotatably provided in the standing state and the tilted state, when the image carrier unit is mounted on the apparatus main body, the pressing member is placed on the moving path of the pressing member in the standing state. Even if there is an obstacle (a component of the apparatus main body), the pressing member in the standing state rotates from the standing state to the tilted state due to a collision with the obstacle. Therefore, it is possible to prevent the pressing member from interfering with the mounting of the image carrier unit, and it is possible to ensure the smooth mounting of the image carrier unit to the apparatus main body.

According to an eighth aspect of the present invention, in the image forming apparatus, the developing cartridge according to any one of the first to seventh aspects and a pressing force input member that inputs a pressing force to the pressing member are provided. It is said.
According to such a configuration, since the developer cartridge capable of maintaining a good pressing state of the developer carrier against the image carrier is provided, the developer from the developer carrier to the image carrier is excellent. Supply can be secured. Therefore, it is possible to achieve a good visible image of the electrostatic latent image formed on the image carrier, and it is possible to form a high quality image.

According to a ninth aspect of the present invention, in the eighth aspect of the invention, an apparatus main body, and an image carrier unit that is detachably attached to the apparatus main body and integrally holds a plurality of image carriers. The developing cartridge is detachably attached to the image carrier unit.
According to such a configuration, the image carrier unit holding a plurality of image carriers can be attached to and detached from the apparatus main body. Therefore, it is possible to facilitate maintenance work such as jam processing and parts replacement.

  In addition, a plurality of developing cartridges can be detachably attached to the image carrier unit. Therefore, the developing cartridge can be individually replaced, and the maintenance cost (maintenance cost) can be reduced.

According to the first aspect of the present invention, it is possible to continue to maintain a good pressing state of the developer carrier against the image carrier.
According to the second aspect of the present invention, it is possible to reduce the number of parts while improving the operability of the developing cartridge.
According to the third aspect of the present invention, the developer carrying member can be reliably urged toward the image carrying member.

According to the fourth aspect of the present invention, it is possible to prevent the developer carrying member from contacting the image carrying member with respect to the image carrying member and the occurrence of press fogging.
According to the fifth aspect of the present invention, it is possible to satisfactorily supply the color developer corresponding to each image carrier.
According to the sixth aspect of the present invention, even if the dead weight of the developing cartridge is changed, the developer carrier is pressed against the image carrier in a predetermined pressing state by adjusting the biasing force of the biasing portion. Can be made.

According to the seventh aspect of the present invention, it is possible to prevent the pressing member from interfering with the mounting of the image carrier unit, and to ensure the smooth mounting of the image carrier unit to the apparatus main body.
According to the eighth aspect of the invention, it is possible to achieve good visualization of the electrostatic latent image formed on the image carrier, and it is possible to form a high-quality image.

  According to the ninth aspect of the present invention, it is possible to facilitate maintenance work such as jam processing and parts replacement, and it is possible to reduce maintenance costs.

1 is a side sectional view showing an embodiment of a color laser printer as an example of a color image forming apparatus of the present invention. FIG. 2 is a side sectional view of the developing cartridge and the drum subunit shown in FIG. 1. FIG. 2 is a perspective view of the drum unit (in a state where four developing cartridges are mounted) shown in FIG. FIG. 2 is a perspective view of the drum unit shown in FIG. 1 (one developing cartridge is being attached / detached and other developing cartridges are detached) as viewed from the upper left front. It is a left view of the drum unit shown in FIG. FIG. 2 is a perspective view of the developing cartridge shown in FIG. 1 as viewed from the left rear, showing a tilted state of the handle. FIG. 2 is a perspective view of the developing cartridge shown in FIG. 1 as seen from the left rear, showing a standing state of the handle. FIG. 2 is a perspective view of the developing cartridge shown in FIG. 1 as viewed from the left front, showing a tilted state of the handle. FIG. 2 is a perspective view of the developing cartridge shown in FIG. 1 as viewed from the left front, showing a standing state of the handle. FIG. 2 is a plan view of the developing cartridge shown in FIG. FIG. 2 is a right side view of the developing cartridge shown in FIG. 1. FIG. 12 is a sectional view of the developing cartridge shown in FIG. 11 taken along a cutting line AA. FIG. 2 is a right side sectional view of the developing cartridge shown in FIG. 1, showing a tilted state of the handle. FIG. 2 is a right side sectional view of the developing cartridge shown in FIG. 1, showing a pressing state of a handle. FIG. 2 is a perspective view of the main body casing and the drum unit shown in FIG. 1 as viewed from the upper right front, and shows a state in which an exterior plate and a front cover of the main body casing are removed and the drum unit is mounted on the main body casing. It is the perspective view seen from the front right upper part of the drum unit shown in FIG. FIG. 17 is a perspective view of the rail and the separation pressing mechanism shown in FIG. FIG. 18 is a perspective view of the linear cam member, the intermediate member, and the synchronous movement mechanism shown in FIG. It is a perspective view for demonstrating the motion of the linear cam member and intermediate member shown in FIG. It is a right view of the linear cam member and intermediate member in the state of Fig.19 (a). It is a right view of the linear cam member and intermediate member in the state of FIG.19 (c). It is a right view of the linear cam member and intermediate member in the state of FIG.19 (e). It is a perspective view which shows other embodiment (aspect provided with a leaf | plate spring member) of a developing cartridge. FIG. 10 is a perspective view showing another embodiment of the developing cartridge (an aspect in which an elastic member is provided over the entire width in the width direction of the upper wall of the developing frame), and shows a tilted state of the handle. FIG. 25 is a perspective view of the developing cartridge shown in FIG. 24, showing the handle standing up. FIG. 10 is a perspective view showing another embodiment of the developing cartridge (an aspect in which an elastic ring is attached to the pressing protrusion), and shows a state of the developing cartridge as viewed from the upper right front. The state seen from the upper left front of the developing cartridge shown in FIG. 26 is shown. FIG. 28 is a perspective view of a left upper end portion of the developing cartridge shown in FIG. 27. It is the perspective view seen from the left front which shows other embodiment (a mode in which a coil spring is provided in a handle), and a tilted state of a handle is shown. It is the perspective view seen from the left front of the developing cartridge shown in FIG. 29, and the standing state of the handle is shown. FIG. 30 is a front view of the developing cartridge shown in FIG. 29 as viewed from the front. FIG. 32 is a cross-sectional view of the developing cartridge shown in FIG. 31 taken along section line BB.

1. 1 is a side sectional view showing an embodiment of a color laser printer as an example of a color image forming apparatus of the present invention.
This color laser printer 1 is a horizontal tandem color laser printer in which a plurality of drum subunits 28 to be described later are arranged in parallel in a horizontal direction, and is disposed in a main body casing 2 as an example of an apparatus main body. A paper feed unit 4 for feeding the paper 3, an image forming unit 5 for forming an image on the fed paper 3, and a paper discharge unit for discharging the paper 3 on which the image is formed 6 is provided.
(1) Main Body Casing The main body casing 2 has a box shape that is substantially rectangular when viewed from the side, and a drum housing space 7 that houses a drum unit 26 described later is formed therein.

  An attachment / detachment port 8 communicating with the drum housing space 7 is formed on one side surface of the main casing 2. A front cover 9 for opening and closing the attachment / detachment port 8 is provided on a side surface where the attachment / detachment port 8 is formed. The front cover 9 tilts to the side of the main body casing 2 to open the attachment / detachment opening 8, rises along one side surface of the main body casing 2, and closes the attachment / detachment opening 8. The drum unit 26 can be attached to and detached from the drum housing space 7 through the attachment / detachment opening 8 with the attachment / detachment opening 8 opened.

In the following description, the side on which the front cover 9 is provided (the right side in FIG. 1) is the front side, and the opposite side (the left side in FIG. 1) is the rear side. Further, when the color laser printer 1 is viewed from the front side, the left and right reference is used. Further, with respect to the drum unit 26 and the developing cartridge 27, the front / rear, left / right, upper / lower are defined in the state where the drum unit 26 and the developing cartridge 27 are attached to the main casing 2 unless otherwise specified.
(2) Paper Feed Unit The paper feed unit 4 is provided at the bottom of the main body casing 2. The paper feed unit 4 includes a paper feed tray 10 that stores the paper 3, a separation roller 11 and a separation pad 12 that are provided above the front end of the paper feed tray 10, and are disposed opposite to each other. The sheet feeding roller 13 provided on the side and the sheet feeding side conveyance path 14 through which the sheet 3 passes are provided.

The sheet feeding side conveyance path 14 is formed in a substantially U shape in a side view, and its upstream end is adjacent to the separation roller 11 and its downstream end is adjacent to a conveyance belt 58 described later from the front side. Yes.
A paper dust removing roller 15 and a pinch roller 16 which are provided on the upper front side of the separation roller 11 and are arranged opposite to each other in the middle of the paper feeding side conveyance path 14, and a pair of registration rollers 17 provided above them. Is provided.

Inside the paper feed tray 10, a paper pressing plate 18 on which the paper 3 is placed in a stacked manner is provided. The sheet pressing plate 18 is supported swingably at the rear end portion, so that the front end portion is disposed below, the placement position along the bottom plate of the sheet feeding tray 10 and the front end portion are disposed above, It is possible to move between an inclined paper feeding position.
A lever 19 that lifts the front end of the paper pressing plate 18 upward is provided below the front end of the paper feed tray 10. The lever 19 is supported in a vertically swingable manner below the front end of the paper pressing plate 18.

As the lever 19 swings, the front end of the paper pressing plate 18 is lifted by the lever 19 and the paper pressing plate 18 is positioned at the paper feeding position.
When the sheet pressing plate 18 is positioned at the sheet feeding position, the uppermost sheet 3 on the sheet pressing plate 18 is pressed by the sheet feeding roller 13, and the separation roller 11 and the separation pad 12 are rotated by the rotation of the sheet feeding roller 13. Paper is fed in between.

When the paper feed tray 10 is detached from the main casing 2, the paper pressing plate 18 is positioned at the placement position. When the paper pressing plate 18 is positioned at the mounting position, the paper 3 can be stacked on the paper pressing plate 18.
The fed paper 3 is sandwiched between the separation roller 11 and the separation pad 12 by the rotation of the separation roller 11, and is fed and conveyed one by one. The transported paper 3 passes between the paper dust removing roller 15 and the pinch roller 16, and after the paper dust is removed, it is transported toward the registration roller 17 along the paper feed side transport path 14.

The registration roller 17 conveys the paper 3 to the conveyance belt 58 after registration.
(3) Image Forming Unit The image forming unit 5 includes a scanner unit 20, a process unit 21, a transfer unit 22, and a fixing unit 23.
(3-1) Scanner Unit The scanner unit 20 is disposed on the upper part of the main body casing 2. The scanner unit 20 includes a support plate 24 extending in the front-rear and left-right directions, and a scanner unit 25 fixed to the upper surface of the support plate 24. In the scanner unit 25, for example, optical members such as four light sources, a polygon mirror, an fθ lens, a reflecting mirror, and a surface tilt correction lens are arranged, and a laser beam based on image data emitted from each light source is The light is deflected and scanned by the polygon mirror, passes through the fθ lens and the surface tilt correction lens, is reflected by the reflecting mirror, and then is irradiated onto the surface of the photosensitive drum 29 for each color described later at high speed scanning.
(3-2) Process Unit The process unit 21 is disposed below the scanner unit 20 and above the paper feed unit 4, and corresponds to each drum unit 26 as an example of one image carrier unit. The four developing cartridges 27 are provided.
(3-2-1) Drum Unit The drum unit 26 includes four drum subunits 28 corresponding to each color. That is, the drum subunit 28 is the black drum subunit 28K. It consists of four units, a yellow drum subunit 28Y, a magenta drum subunit 28M, and a cyan drum subunit 28C.

The respective drum subunits 28 are arranged in parallel at intervals in the front-rear direction, and more specifically, the black drum subunit 28K from the front side toward the rear side. A yellow drum subunit 28Y, a magenta drum subunit 28M, and a cyan drum subunit 28C are sequentially arranged.
As will be described later, each drum subunit 28 includes a pair of side frames 104 and a center frame 105 installed between them (see FIG. 4).

FIG. 2 is a side sectional view of the developing cartridge 27 and the drum subunit 28. In FIGS. 1 and 2, the handle 214 described later is not shown.
As shown in FIG. 2, each drum subunit 28 holds a photosensitive drum 29 as an example of an image carrier, a scorotron charger 30, and a cleaning brush 31.
The photosensitive drum 29 is arranged along the left-right direction, has a cylindrical shape, and is arranged along the axial direction of the drum body 32 formed by a positively chargeable photosensitive layer whose outermost layer is made of polycarbonate. The drum shaft 33 is provided. The drum body 32 is provided so as to be rotatable with respect to the drum shaft 33. Both end portions in the axial direction of the drum shaft 33 are inserted into a pair of side frames 104 (see FIG. 4), and are rotatably supported by a side plate 103 (see FIG. 4) described later. The photosensitive drum 29 is rotated by a driving force from a motor (not shown) provided in the main body casing 2 during image formation.

  The scorotron charger 30 is disposed diagonally above and behind the photosensitive drum 29 so as to face the photosensitive drum 29 with a space therebetween and is held by the center frame 105. The scorotron charger 30 includes a discharge wire 34 disposed to face the photosensitive drum 29 with a space therebetween, and a grid 35 provided between the discharge wire 34 and the photosensitive drum 29. At the time of image formation, a high voltage is applied to the discharge wire 34 to cause corona discharge of the discharge wire 34, and a voltage is applied to the grid 35 to control the amount of charge supplied to the photosensitive drum 29 while controlling the photosensitive drum 29. Are uniformly charged to the positive polarity.

The cleaning brush 31 is disposed behind the photosensitive drum 29 so as to face and contact the photosensitive drum 29, and is held by the center frame 105. During image formation, a cleaning bias is applied to the cleaning brush 31.
(3-2-2) Developing Cartridge As shown in FIG. 1, the developing cartridge 27 is detachably provided corresponding to the drum subunit 28 corresponding to each color. That is, the developing cartridge 27 is detachably attached to the black developing cartridge 27K detachably attached to the black drum subunit 28K, the yellow developing cartridge 27Y detachably attached to the yellow drum subunit 28Y, and the magenta drum subunit 28M. The magenta developing cartridge 27M is mounted, and the cyan developing cartridge 27C is detachably mounted on the cyan drum subunit 28C.

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

The toner storage chamber 43 stores toner corresponding to each color. More specifically, corresponding to each developing cartridge 27, black toner is applied to the black developing cartridge 27K, yellow toner to the yellow developing cartridge 27Y, magenta toner to the magenta developing cartridge 27M, and cyan toner to the cyan developing cartridge 27C. Each is housed.
As the toner corresponding to each color, a positively charged non-magnetic one-component polymerized toner is used. The polymerized toner has a substantially spherical shape and is a suspension polymerization of a styrene monomer such as styrene or an acrylic monomer such as acrylic acid, alkyl (C1 to C4) acrylate, or alkyl (C1 to C4) methacrylate. Obtained by copolymerization by a known polymerization method such as a binder resin as a main component, and by adding a colorant corresponding to each color, a charge control agent, a wax and the like, toner base particles are obtained. In addition, an external additive is added to improve the fluidity.

  As the colorant, the above-described black, yellow, magenta and cyan colorants are blended corresponding to each color. Moreover, as a charge control agent, for example, an ionic monomer having an ionic functional group such as an ammonium salt and an ionic monomer such as a styrene monomer or an acrylic monomer can be copolymerized. A charge control resin obtained by copolymerization with a monomer is blended. As external additives, for example, powders of metal oxides such as silica, aluminum oxide, titanium oxide, strontium titanate, cerium oxide and magnesium oxide, inorganic powders such as carbide powders and metal salt powders are blended. Has been.

  The agitator 37 is provided in the toner storage chamber 43. The agitator 37 is provided over the axial direction of the agitator rotating shaft 47 that is rotatably supported on both side walls 201 described later of the developing frame 36, and the stirring member 48 that extends radially outward from the rotating shaft. And. At the time of image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted to the agitator rotating shaft 47, and the agitating member 48 moves around in the toner storage chamber 43.

  The supply roller 38 is provided below the communication port 45 in the developing chamber 44. The supply roller 38 includes a metal supply roller shaft 49 that is rotatably supported on both side walls 201 of the developing frame 36, and a sponge roller 50 made of a conductive sponge that covers the periphery of the supply roller shaft 49. I have. At the time of image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted, and the supply roller 38 is rotated.

The developing roller 39 is provided in the developing chamber 44 obliquely rearward and downward with respect to the supply roller 38. The developing roller 39 includes a metal developing roller shaft 51 that is rotatably supported by the developing frame 36 and a rubber roller 52 made of conductive rubber that covers the periphery of the developing roller shaft 51.
The rubber roller 52 is coated with a rubber roller layer made of conductive urethane rubber, silicone rubber, EPDM rubber or the like containing carbon fine particles, and the surface of the rubber roller layer, and mainly contains urethane rubber, urethane resin, polyimide resin, or the like. It consists of a two-layer structure with a coat layer.

The developing roller 39 is disposed so that the rubber roller 52 and the sponge roller 50 are in pressure contact with the supply roller 38. The developing roller 39 is disposed so as to be exposed downward from the opening 41 of the developing chamber 44.
During image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted, and the developing roller 39 is rotated. A developing bias is applied to the developing roller 39.

The layer thickness regulating blade 40 is provided in the developing chamber 44 so as to be in pressure contact with the developing roller 39 from above. The layer thickness regulating blade 40 includes a blade 53 made of a metal leaf spring member, and a pressing portion 54 having a semicircular cross section made of insulating silicone rubber provided at the free end of the blade 53.
The base end portion of the blade 53 is fixed to the partition wall 42 by a fixing member 55, and the pressing portion 54 provided at the free end portion of the blade 53 against the rubber roller 52 of the developing roller 39 by the elastic force of the blade 53. Press contact from above.
(3-2-3) Developing Operation in Process Unit In each developing cartridge 27, the toner corresponding to each color stored in the toner storage chamber 43 moves to the communication port 45 by its own weight and is stirred by the agitator 37. While being done, it is discharged from the communication port 45 to the developing chamber 44.

The toner discharged from the communication port 45 to the developing chamber 44 is supplied to the supply roller 38. The toner supplied to the supply roller 38 is supplied to the developing roller 39 by the rotation of the supply roller 38. At this time, the toner is positively rubbed between the supply roller 38 and the developing roller 39 to which the developing bias is applied. Charged.
The toner supplied to the developing roller 39 enters between the pressing portion 54 of the layer thickness regulating blade 40 and the rubber roller 52 of the developing roller 39 as the developing roller 39 rotates, and a thin layer having a constant thickness. Is carried on the surface of the rubber roller 52.

On the other hand, in the drum subunit 28 corresponding to each developing cartridge 27, the scorotron charger 30 generates corona discharge to uniformly positively charge the surface of the photosensitive drum 29.
The surface of the photosensitive drum 29 is uniformly positively charged by the scorotron charger 30 as the photosensitive drum 29 rotates, and then exposed by high-speed scanning of the laser beam from the scanner unit 20 to form on the paper 3. An electrostatic latent image corresponding to the power image is formed.

  When the photosensitive drum 29 further rotates, the positively charged toner carried on the surface of the developing roller 39 comes into contact with the surface of the photosensitive drum 29 when the developing roller 39 rotates and contacts the photosensitive drum 29. The formed electrostatic latent image, that is, the surface of the uniformly positively charged photosensitive drum 29 is supplied to an exposed portion exposed to a laser beam and having a lowered potential. As a result, the electrostatic latent image on the photosensitive drum 29 is visualized by development, and a toner image by reversal development is carried on the surface of the photosensitive drum 29 corresponding to each color.

The transfer residual toner remaining on the photosensitive drum 29 after the transfer is collected by the developing roller 39. Further, the paper dust from the paper 3 adhering to the photosensitive drum 29 after the transfer is collected by the cleaning brush 31.
(3-3) Transfer Unit As shown in FIG. 1, the transfer unit 22 is disposed along the front-rear direction in the main body casing 2 above the paper feed unit 4 and below the process unit 21. Yes. The transfer unit 22 includes a driving roller 56, a driven roller 57, a conveyance belt 58, a transfer roller 59, and a cleaning unit 60.

The driving roller 56 and the driven roller 57 are arranged to face each other with a space in the front-rear direction, the driving roller 56 is arranged behind the cyan drum subunit 28C, and the driven roller 57 is from the black drum subunit 28K. Is also placed forward.
The conveyance belt 58 is an endless belt, and is formed from a conductive resin film such as conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed. The conveyor belt 58 is wound between the driving roller 56 and the driven roller 57.

  During image formation, a driving force from a motor (not shown) provided in the main body casing 2 is transmitted to the driving roller 56, and the driving roller 56 is rotated. Then, the conveyor belt 58 rotates between the driving roller 56 and the driven roller 57 so as to rotate in the opposite direction to the photosensitive drum 29 at the transfer position where the conveying belt 58 faces and contacts the photosensitive drum 29 of each drum subunit 28. At the same time, the driven roller 57 is driven.

  The transfer roller 59 is provided in the conveyance belt 58 wound between the driving roller 56 and the driven roller 57 so as to face each photosensitive drum 29 with the conveyance belt 58 interposed therebetween. Each transfer roller 59 has a metal roller shaft covered with a rubber roller made of conductive rubber. Each transfer roller 59 is provided so as to be driven and rotated in the same direction as the circumferential movement direction of the conveyor belt 58 at a transfer position facing and contacting the conveyor belt 58. A transfer bias is applied from a high-voltage substrate (not shown) provided in FIG.

The cleaning unit 60 is disposed below the conveying belt 58 wound between the driving roller 56 and the driven roller 57, and the primary cleaning roller 61, the secondary cleaning roller 62, the scraping blade 63, and the toner storage unit 64. It has.
The primary cleaning roller 61 is disposed so as to contact the lower conveyance belt 58 on the side opposite to the upper conveyance belt 58 with which the photosensitive drum 29 and the transfer roller 59 are in contact. It is provided so as to be driven and rotated in the same direction as the circumferential movement direction. A primary cleaning bias is applied to the primary cleaning roller 61 during image formation.

The secondary cleaning roller 62 is disposed so as to come into contact with the primary cleaning roller 61 from below, and is provided to rotate in the direction opposite to the rotation direction of the primary cleaning roller 61 at the contact position. A secondary cleaning bias is applied to the secondary cleaning roller 62 during image formation.
The scraping blade 63 is provided so as to contact the secondary cleaning roller 62 from below.

The toner storage unit 64 is provided below the primary cleaning roller 61 and the secondary cleaning roller 62 so as to store toner falling from the secondary cleaning roller 62.
Then, the sheet 3 fed from the sheet feeding unit 4 is transferred to each drum subunit 28 from the front side to the rear side by the conveyance belt 58 that is circulated by the driving roller 56 and the driven roller 57. The toner images of the respective colors carried on the photosensitive drums 29 of the respective drum subunits 28 are sequentially transferred during the conveyance so as to pass through the corresponding transfer positions. An image is formed.

  That is, for example, when a black toner image carried on the surface of the photosensitive drum 29 of the black drum subunit 28K is transferred to the paper 3, it is then carried on the surface of the photosensitive drum 29 of the yellow drum subunit 28Y. The yellow toner image is transferred onto the paper 3 on which the black toner image has already been transferred, and the magenta toner image carried on the surface of the photosensitive drum 29 of the magenta drum subunit 28M by the same operation. A cyan toner image carried on the surface of the photosensitive drum 29 of the cyan drum subunit 28 </ b> C is transferred in a superimposed manner, whereby a color image is formed on the paper 3.

On the other hand, in the above transfer operation, the toner adhering to the surface of the conveyor belt 58 is first transferred from the surface of the conveyor belt 58 to the primary cleaning roller 61 by the primary cleaning bias in the cleaning unit 60, and further to 2 The toner is transferred to the secondary cleaning roller 62 by the next cleaning bias. Thereafter, the toner transferred to the secondary cleaning roller 62 is scraped off by the scraping blade 63, falls from the secondary cleaning roller 62, and is stored in the toner storage portion 64.
(3-4) Fixing Unit The fixing unit 23 is located behind the cyan drum subunit 28C in the main body casing 2 and faces the transfer position where the photosensitive drum 29 and the conveyance belt 58 are in contact with each other in the front-rear direction. Is arranged. The fixing unit 23 includes a heating roller 65 and a pressure roller 66.

The heating roller 65 is made of a metal base tube having a release layer formed on the surface thereof, and a halogen lamp is provided along the axial direction thereof. The surface of the heating roller 65 is heated to a fixing temperature by a halogen lamp.
The pressure roller 66 is disposed below the heating roller 65 so as to face the heating roller 65. The pressure roller 66 presses the heating roller 65 from below.

The color image transferred onto the sheet 3 is conveyed to the fixing unit 23 and is thermally fixed to the sheet 3 while the sheet 3 passes between the heating roller 65 and the pressure roller 66. Thereby, formation of an image on the sheet 3 is achieved.
(4) Paper Discharge Unit In the paper discharge unit 6, the paper discharge side transport path 67 of the paper 3 has an upstream end adjacent to the fixing unit 23 at the lower side and a downstream end at the upper side. Adjacent to the tray 68, the sheet 3 is formed in a substantially U shape in a side view so that the sheet 3 is fed toward the rear side, and after being reversed, the sheet 3 is ejected toward the front side.

A transport roller 69 and a pinch roller 70 that face each other are provided in the middle of the paper discharge side transport path 67. A pair of paper discharge rollers 71 is provided at the downstream end of the paper discharge side conveyance path 67.
The paper discharge unit 6 is provided with a paper discharge tray 68. The paper discharge tray 68 is formed so that the upper wall of the main casing 2 is formed so as to be gradually depressed from the front side toward the rear side, and the discharged papers 3 can be placed in a stacked manner.

The sheet conveyed from the fixing unit 23 is conveyed by the conveying roller 69 and the pinch roller 70 along the sheet discharge side conveying path 67 and is discharged onto the sheet discharge tray 68 by the sheet discharge roller 71.
2. Drum Unit FIG. 3 is a perspective view of the drum unit 26 (with four developing cartridges 27 mounted) as viewed from the upper left rear, and FIG. 4 shows the drum unit 26 (one developing cartridge 27 is in the process of being attached and detached). FIG. 7 is a perspective view of the developing cartridge 27 as viewed from the upper left front. FIG. 5 is a left side view of the drum unit 26.

  The drum unit 26 includes four drum subunits 28 corresponding to each color, a front beam 101 and a rear beam 102 disposed on both sides in the front-rear direction of the four drum subunits 28 disposed in parallel along the front-rear direction, A beam 101, four drum subunits 28, and a rear beam 102 are provided with a pair of side plates 103 that sandwich both sides in the width direction (left-right direction).

The drum unit 26 includes four drum subunits 28, a front beam 101, a rear beam 102, and a pair of side plates 103, and is detachably attached to the drum housing space 7 (see FIG. 1) in the main body casing 2. Is done.
(1) Drum Subunit As shown in FIG. 4, the drum subunit 28 includes a pair of side frames 104 arranged to face each other with a gap in the width direction, and the width between the side frames 104 along the width direction. A center frame 105 (see FIG. 2) is provided.

Each side frame 104 is formed in a flat plate shape using a resin material. The drum shaft 33 of the photosensitive drum 29 is inserted into each side frame 104.
Each side frame 104 is formed with a guide groove 106 for guiding attachment / detachment of the developing cartridge 27 with respect to the drum subunit 28. The guide groove 106 is formed along a substantially vertical direction from the rear upper end edge of the side frame 104 to the vicinity of the front lower end of the side frame 104, and the developing roller 39 is exposed to the lower end portion (the deepest portion). It is arranged corresponding to the position of the developing roller shaft 51 at a position in contact with the drum 29. A collar member 205 described later is slidably received in the guide groove 106.

Each side frame 104 is formed with a boss 107. The boss 107 is formed in a cylindrical shape projecting outward in the width direction from the side frame 104, and a window 206 (to be described later) of the developing cartridge 27 is opposed in the width direction in a state where the developing cartridge 27 is mounted on the drum subunit 28. Are arranged to be.
In addition, a coupling inner insertion hole 109 is formed in the left side frame 104 so that a coupling passive gear 208 (described later) of the developing cartridge 27 faces in the width direction. The coupling inner insertion hole 109 is formed as a round hole penetrating the thickness direction of the left side frame 104.

The center frame 105 is formed using a resin material. Support rollers 110 for supporting the developing cartridge 27 are provided at both ends in the width direction of the upper end portion of the center frame 105. The support roller 110 is rotatably supported by a rotation shaft (not shown) extending in the width direction along the upper end portion of the center frame 105.
(2) Front beam The front beam 101 is integrally formed using a resin material, and is arranged on the front side of the four drum subunits 28 arranged in parallel along the front-rear direction. It is built in.

The front beam 101 includes a front side grip portion 111 attached to the center in the width direction and a support shaft 112 that rotatably supports the front side grip portion 111.
The front side grip portion 111 is substantially U-shaped, and at the center in the width direction, each free end portion is rotatably supported by the support shaft 112 and is stowed along the front beam 101 (see FIG. 3). ) And an operation position (see FIG. 4) tilting forward of the front beam 101 so as to be swingable.

The support shaft 112 is disposed so as to penetrate the front beam 101 along the width direction, and is supported by the front beam 101. Further, both end portions in the width direction of the support shaft 112 protrude outward in the width direction from the front beam 101, and further protrude outward in the width direction through the side plate 103.
(3) Rear beam The rear beam 102 is integrally formed using a resin material, and is arranged on the rear side of the four drum subunits 28 arranged in parallel along the front-rear direction. It is erected.

As shown in FIG. 3, the rear beam 102 is formed in a substantially U-shape in plan view with the rear opened, and a back side grip 113 is integrally provided at the center in the width direction. The rear side grip 113 is substantially U-shaped when viewed from the back, and each free end thereof is connected to the rear beam 102 and is provided so as to incline from the rear lower side to the front upper side and to project obliquely upward from the rear beam 102. It has been.
(4) Side plate Each side plate 103 is made of a material having higher rigidity than the resin material forming each drum subunit 23, front beam 101 and rear beam 102, for example, a metal or fiber reinforced resin, preferably a steel plate. Formed from.

Each side plate 103 has a substantially elongated rectangular plate shape in side view extending in the front-rear direction, and has a front end portion with respect to the front beam 101, the four drum subunits 28, and the rear beam 102 arranged in parallel along the front-rear direction. It is formed so as to face the front beam 101 and its rear end face the rear beam 102, and is fixed to these.
An upper end portion of each side plate 103 is bent outward in the width direction so as to have an L-shaped cross section, and a flange portion 114 is formed extending outward in the width direction over the front-rear direction. The flange 114 extends in a straight line along the front-rear direction (horizontal direction).

  In addition, the rear end portion of each side plate 103 is formed in a substantially L shape in a side view when the upper end portion extends rearward, and two roller members 118 are rotatably provided in a portion extending rearward. Yes. The two roller members 118 are arranged with the spacer 119 interposed therebetween in the front-rear direction. The front roller member 118 is disposed below the flange 114, and the rear roller member 118 is disposed behind the rear end of the flange 114.

  Furthermore, a notch 120 having a shape that is cut out from the rear edge in a substantially U shape in a side view is formed at the rear end of each side plate 103. The notch 120 is fitted with a positioning shaft (not shown) disposed in the main casing 2 in a state where the drum unit 26 is mounted on the main casing 2, whereby the drum unit 26 is fitted to the main casing 2. Positioned against.

  Each side plate 103 is formed with four light transmission holes 115 that receive the bosses 107 of the drum subunits 28 at the upper end. Four light transmission holes 115 are formed at the upper end of the side plate 103 at intervals from each other along the front-rear direction. The light transmitting hole 115 is formed as a round hole penetrating in the thickness direction at a position facing the boss 107 of each drum subunit 28 in the width direction. In each light transmission hole 115, a boss 107 of each drum subunit 28 is fitted so that each boss 107 is exposed outward in the width direction, whereby each side plate of each drum subunit 28 is fitted. The rotation about the drum shaft 33 with respect to 103 is restricted.

Further, each side plate 103 is formed with a shaft hole 116 through which the axial end of each drum shaft 33 is inserted at the lower end.
Coupling outer insertion holes 117 are formed in the left side plate 103 so that the coupling passive gears 208 of the developing cartridges 27 face each other in the width direction. Four coupling outer insertion holes 117 are formed at the center in the vertical direction of the side plate 103 and spaced from each other along the front-rear direction. The coupling outer insertion hole 117 is formed as a round hole penetrating in the thickness direction at a position facing the coupling inner insertion hole 109 of each drum subunit 28 in the width direction.
3. 6 and 7 are perspective views of the developing cartridge 27 as viewed from the left rear, and FIGS. 8 and 9 are perspective views of the developing cartridge 27 as viewed from the left front. 10 is a plan view of the developing cartridge 27, FIG. 11 is a right side view of the developing cartridge 27, and FIG. 12 is a cross-sectional view taken along a cutting line AA shown in FIG. 13 and 14 are right side cross-sectional views of the developing cartridge 27. FIG. 13 and 14, the supply roller 38 and the developing roller 39 are shown in a simplified manner.
(1) Developing Cartridge The developing frame 36 of the developing cartridge 27 includes a pair of side walls 201 facing each other in the width direction, an upper wall 202 constructed between upper end edges of both side walls 201, and front end edges of both side walls 201. A front wall 203 to be installed and a rear wall 204 to be installed between rear end edges of both side walls 201 are integrally provided, and the developing roller is formed by the lower end edges of both side walls 201, front wall 203 and rear wall 204. An opening 41 that exposes 39 is formed.

A window 206 for detecting the remaining amount of toner stored in the toner storage chamber 43 is embedded in the side walls 201. These windows 206 are arranged to face each other with the toner storage chamber 43 interposed therebetween, and allow light for detecting the remaining amount of toner to pass along the width direction.
As shown in FIGS. 6 to 9, the left side wall 201 is provided with a gear mechanism portion covered with a gear cover 207. The gear mechanism section includes a coupling passive gear 208 exposed from the gear cover 207 and a gear train 230 (see FIG. 12) that meshes with the coupling passive gear 208 in the gear cover 207.

A cylindrical gear arrangement portion 209 is formed at the lower end portion of the gear cover 207 so as to protrude outward in the width direction, and the coupling passive gear 208 is arranged in the gear arrangement portion 209 and the gear arrangement portion 209. It is exposed from the front end surface.
A coupling shaft (not shown) provided in the main body casing 2 is coupled to the coupling passive gear 208 so as to be movable back and forth and not relatively rotatable. A motor (not shown) provided in the main body casing 2 from the coupling shaft. )) Is input.

  The gear train 230 includes an agitator driving gear fixed to the rotation shaft 47 of the agitator 37, a supply roller driving gear fixed to the supply roller shaft 49 of the supply roller 38, and a developing roller fixed to the developing roller shaft 51 of the developing roller 39. A drive gear and the like are provided, and these mesh with the coupling passive gear 208 via an intermediate gear or the like. As a result, the driving force input to the coupling passive gear 208 is transmitted to the agitator 37, the supply roller 38 and the developing roller 39 via the gear train 230.

As shown in FIG. 11, a cap 210 that closes a toner filling port (not shown) for filling the toner storage chamber 43 with toner is disposed on the right side wall 201, as shown in FIG. 11.
Further, a bearing member 211 that rotatably supports the right shaft end portion of the developing roller shaft 51 is provided at the lower end portion of the right side wall 201. As shown in FIG. 12, the right end portion of the developing roller shaft 51 is rotatably inserted into the bearing member 211, and the left end portion thereof is rotatably inserted into the left side wall 201. The shaft 51 is rotatably supported by the developing frame 36. The left end portion and the right end portion of the developing roller shaft 51 protrude outward in the width direction from the gear cover 207 and the bearing member 211, respectively, and a collar member 205 is covered with each protruding portion.

Further, as shown in FIGS. 6 to 9, the upper end portions of both side walls 201 are spaced apart as an example of a substantially cylindrical protruding portion that protrudes outward in the width direction from the connection portion with the upper end portion of the rear wall 204. A protrusion 212 is formed.
The upper wall 202 is provided with a handle 214 that also serves as a pressing member that is gripped when the developing cartridge 27 is moved. The handle 214 is formed in a thin plate shape that is long in the width direction, and stands in a standing state (see FIGS. 7 and 9) that stands substantially perpendicular to the upper wall 202, and tilts forward from the standing state to the upper wall. It is provided so as to be able to swing between a tilted state (see FIGS. 6, 8 and 13) close to 202 and a pressed state (see FIG. 14) closer to the upper wall 202 than the tilted state.

  More specifically, as shown in FIGS. 13 and 14, at the rear end of the upper wall 202, a handle support portion having a substantially semicircular shape in side view protruding upward at both ends in the width direction thereof. 215 is integrally formed. The handle support portion 215 is formed with a through hole 229 that penetrates in the width direction. On the other hand, as shown in FIGS. 6 and 7, notches 231 into which the handle support portions 215 can be fitted are formed at both ends in the width direction at the rear end portion of the handle 214. Each notch 231 is provided with a substantially L-shaped elastic deformation portion 232 in plan view with a base end connected to the left side surface thereof. The elastic deformation portion 232 has a free end portion opposed to the right side surface of the notch portion 231 with a gap in the width direction, and a handle between the free end portion of the elastic deformation portion 232 and the right side surface of the notch portion 231. The support part 215 is fitted. Support shafts 233 project from the free end portion of the elastic deformation portion 232 and the right side surface of the cutout portion 231 so as to approach each other, and the elastic deformation portion 232 is deformed to support these support shafts 233. The handle support portions 215 are fitted into the respective notches 231 in a state where the distance between them is widened, and then the deformation of the elastic deformation portion 232 is released, and each support shaft 233 is inserted into the through hole 229 of the handle support portion 215. As a result, the handle 214 is swingably attached to the handle support portion 215.

  Further, as shown in FIGS. 9 and 12, the front wall 202 has a front end portion in the width direction (the axial direction of the developing roller 39) and a width direction of the rubber roller 50 of the developing roller 39 in the width direction. A spring guide member 216 as an example of a cylindrical guide member is formed at an interval substantially equal to the length (length in the axial direction). Each spring guide member 216 is opposed to each handle support portion 215 with a space in the front-rear direction, and is opposed to both end portions of the developing roller 39 in the width direction of the rubber roller 52. Further, in each spring guide member 216, as shown in FIG. 13 and FIG. 14, a contact member 217 that can advance and retract in the vertical direction and an elastic member that constantly biases the contact member 217 upward. An example coil spring 218 is provided.

  The abutting member 217 has a substantially circular main body 219 with a convex upper surface, a boss 220 protruding downward from the center of the lower surface of the main body 219, and a spring from the peripheral edge of the lower surface of the main body 219. A cylindrical extension 221 extending along the inner peripheral surface of the guide member 216 is integrally provided. The extending portion 221 is formed with a plurality of locking claw portions 222, and each locking claw portion 222 is fitted into a groove portion 223 formed in the spring guide member 216, and a tip portion thereof is an upper end of the groove portion 223. The contact member 217 is prevented from being detached from the spring guide member 216 by being locked to the portion.

The coil spring 218 has a spring mounting boss 224 formed on the upper wall 202 inserted in the lower end portion and a boss portion 220 of the contact member 217 inserted in the upper end portion between the contact member 217 and the upper wall 202. It is provided in a compressed state.
As shown in FIG. 9, on the lower surface of the handle 214 (the surface facing the upper wall 202), as an example of a transmission portion that can receive the corresponding contact member 217 at a position corresponding to each contact member 217. The recessed part 225 is formed. When the handle 214 is tilted to the tilted state, each contact member 217 is received in each recess 225, and the tip of each contact member 217 contacts the bottom surface of each recess 225 (the lower surface of the handle 214).

Further, as shown in FIG. 10, the handle 214 is formed with a gripping hole 226 having a substantially rectangular shape in plan view that is long in the width direction at the center in the width direction. Thereby, the handle 214 can be gripped by putting a finger into the gripping hole 226.
Further, the handle 214 is formed with pressing protrusions 227 that are substantially cylindrical in a side view and project outward in the width direction at both ends in the width direction at the front end. As shown in FIG. 10, each pressing protrusion 227 is formed in such a length that the front end surface thereof is positioned on the plane S including the front end surface of the separation protrusion 212 protruding to the same side. That is, each pressing protrusion 227 is disposed at the same position as the distal end surface of the separation protrusion 212 whose distal end surface projects on the same side in the width direction. Each pressing protrusion 227 is disposed at a position lower than the separation protrusion 212 as shown in FIG. 11 in a state where the developing cartridge 27 is mounted on the drum subunit 28 and the handle 214 is inclined. .

As shown in FIGS. 8 and 9, the front wall 203 is formed with supported protrusions 228 having a substantially trapezoidal shape in a side view projecting forward at both ends in the width direction.
(2) Attaching / detaching the developing cartridge to / from the drum unit The developing cartridge 27 corresponding to each color puts a finger into the holding hole 226 of the handle 214 to hold the handle 214, and as shown in FIG. A drum subunit 28 corresponding to the developing cartridge 27 is mounted.

  More specifically, the collar members 205 at both ends in the axial direction of the developing roller shaft 51 of the developing cartridge 27 are inserted into the guide grooves 106 of the corresponding side frames 104 of the corresponding drum subunit 28, and along the guide grooves 106. Then, the developing cartridge 27 is pushed downward with respect to the drum subunit 28. When the developing roller 39 comes into contact with the photosensitive drum 29, further pressing of the developing cartridge 27 is restricted. Then, due to the weight of the developing cartridge 27, the developing cartridge 27 falls about the developing roller shaft 51 with its upper end portion leaning against the front center frame 105, and is formed on the front wall 203 of the developing frame 36. The supported protrusion 228 is supported in contact with the support roller 110 of the center frame 105. As a result, the developing cartridge 27 is positioned with respect to the drum subunit 28, and the mounting of the developing cartridge 27 to the drum subunit 28 is achieved.

After the developing cartridge 27 is mounted in this manner, when the hand is released from the handle 214 in the standing state, the handle 214 is tilted from the standing state to the tilted state with the support shaft 233 as a fulcrum by its own weight.
When all the developing cartridges 27 are attached to the drum subunit 28, as shown in FIG. 3, the front side grip portion 111 of the front beam 101, the handle 214 of each developing cartridge 27, and the rear side of the rear beam 102 The grip portion 113 is disposed so as to overlap along the front-rear direction.

On the other hand, in a state where the developing cartridge 27 is mounted on the drum unit 26 (drum subunit 28), the handle 214 is gripped, the handle 214 is raised from the tilted state to the standing state, and lifted upward, whereby the developing cartridge 27 is removed from the drum unit. 26 can be detached.
4). FIG. 15 is a perspective view of the main body casing 2 and the drum unit 26 as seen from the upper right front. The exterior plate of the main body casing 2 and the front cover 9 are removed, and the drum unit 26 is attached to the main body casing 2. Shows the state.

  The main body casing 2 includes a pair of main body frames 301 that are opposed to each other in the width direction across the drum unit 26, and a rail 302 for guiding attachment / detachment of the drum unit 26 and an inner surface of each main body frame 301. A separation pressing mechanism 303 for separating and pressing the developing roller 39 of the developing cartridge 27 mounted on the drum unit 26 against the photosensitive drum 29 is provided.

In FIG. 15, only the left side separation pressing mechanism 303 is shown.
FIG. 16 is a perspective view of the drum unit 26 and the left and right rails 302 and the separation pressing mechanism 303 as seen from the upper right front. FIG. 17 is a perspective view of the left and right rails 302 and the separation pressing mechanism 303 as seen from the upper right front.
(1) Rails The left and right rails 302 are opposed to each other in the width direction with the drum unit 26 interposed therebetween. Each rail 302 includes a rail fixing portion 304 disposed to face the front end surface of the main body frame 301, a rail main body portion 305 extending in the front-rear direction (horizontal direction) along the inner side surface of the main body frame 301, and a rail fixing portion 304, A connecting portion 306 that connects the rail main body portion 305 is integrally provided.

The rail fixing portion 304 is fixed to the front end surface of the main body frame 301 by screws 307.
The rail main body 305 is formed in a substantially L-shaped cross section with its lower end bent toward the inner side in the width direction, and the drum unit 26 is mounted on the main casing 2 in a horizontally extending portion. The flanges 114 of the side plates 103 of the drum unit 26 are placed.

The connecting portion 306 is formed so as to connect the end edge on the inner side in the width direction of the rail fixing portion 304 and the front end edge of the rail main body portion 305. The connecting portion 306 supports a roller support shaft 308 penetrating in the width direction. Rail rollers 309 rotatably supported by the roller supporting shaft 308 are provided on the inner surface of the connecting portion 306 in the width direction. Opposed. The uppermost end portion of the peripheral surface of the rail roller 309 is located above the lower end portion (a portion extending horizontally) of the rail body portion 305.
(2) Mounting of drum unit to main body casing In order to mount the drum unit 26 to the main body casing 2, first, the front side grip portion 111 and the back side grip portion 113 (see FIG. 3) of the drum unit 26 are respectively gripped with both hands, The drum unit 26 is lifted. Then, as shown in FIG. 1, the front cover 9 is tilted to open the attachment / detachment opening 8, and the drum unit 26 enters from the attachment / detachment opening 8 toward the drum housing space 7.

  At this time, each roller member 118 provided at the rear end portion of the drum unit 26 rolls on the rail main body 305 of the rail 302. Also, let go of the back side gripping part 113 and place the both flanges 114 of the drum unit 26 on the left and right rail rollers 309, respectively. When the drum unit 26 is pushed rearward in this state, each roller member 118 rolls on the rail main body 305, and the flange 114 slides on each rail roller 309, whereby the drum unit 26 moves smoothly. To do. Further, the separation protrusion 212 and the pressing protrusion 227 of each developing cartridge 27 slide on a cam accommodating portion 323 of a holder fixing portion 322 described later.

  Then, each roller member 118 is dropped from the rail 302 to the back side, the flange 114 is dropped from the rail roller 309 to the back side of each rail roller 309, and each flange 114 is horizontal to the rail body 305. Is placed on a portion extending in the direction, the pressing protrusion 227 and the separation protrusion 212 of each developing cartridge 27 are received by a pressing protrusion receiving portion 325 and a separation protrusion receiving portion 326, which will be described later, and the drum unit 26 with respect to the main body casing 2 is received. Installation is completed.

Thereafter, the hand is released from the front side grip portion 111, the front cover 9 is closed, and the attachment / detachment opening 8 is closed by the front cover 9. When the front cover 9 is closed, the front gripping portion 111 is rotated from the standing state (see FIG. 4) to the storage position (see FIG. 3) with the support shaft 112 as a fulcrum in conjunction with this.
(3) Separation Press Mechanism As shown in FIG. 17, the separation press mechanism 303 is a linear cam member 310 as an example of a pair of pressing force input members, and an intermediate provided for each linear cam member 310. A member 311, a cam holder 312 that holds each linear cam member 310 so as to be linearly movable in the front-rear direction, and a synchronous movement mechanism 313 that linearly moves the pair of linear cam members 310 synchronously. .

  FIG. 18 is a perspective view of the linear cam member 310, the intermediate member 311 and the synchronous movement mechanism 313 as seen from the upper right front. That is, FIG. 18 is a perspective view of the separating and pressing mechanism 303 as viewed from the upper right front side with the cam holder 312 omitted. FIG. 19 is a perspective view for explaining the movement of the linear cam member 310 and the intermediate member 311. Further, FIG. 20 is a right side view of the linear cam member 310 and the intermediate member 311 in the state of FIG. 19A, and FIG. 21 is a linear cam member 310 and the intermediate member in the state of FIG. 311 is a right side view, and FIG. 22 is a right side view of the linear cam member 310 and the intermediate member 311 in the state of FIG.

The linear cam member 310 includes a thin plate-like cam main body plate 314 extending in the front-rear direction along the inner surface of the main body frame 301 (see FIG. 15), and four provided on the inner surface in the width direction of the cam main body plate 314. And an operation member 315.
The cam body plate 314 is formed with four substantially rectangular holes 316 that are long in the front-rear direction and are equally spaced in the front-rear direction.

  The four operation members 315 are disposed on the front side of the four rectangular holes 316, respectively. Each operation member 315 is formed in a crank shape in a side view, extends along the upper end edge of the cam main body plate 314, a pressing action portion 317 for pressing the pressing protrusion 227 of the developing cartridge 27 downward, and the cam main body plate 314. As shown later, the contact / separation action part 318 for rotating the intermediate member 311, and the connection for connecting the rear end part of the pressing action part 317 and the front end part of the contact / separation action part 318 are extended. The unit 319 is integrally provided.

As shown in FIGS. 20 to 22, a protruding projection 320 protruding upward is formed at the rear end of the contact / separation operating portion 318.
Further, the foremost operating member 315 has a different shape from the other three operating members 315 (hereinafter referred to as “the rear three operating members 315”). That is, the pressing action part 317 of the foremost operation member 315 is formed to have a longer length in the front-rear direction than the pressing action parts 317 of the three rear operation members 315. Further, the contact / separation operating portion 318 of the foremost operation member 315 is formed to have a shorter length in the front-rear direction than the contact / separation operation portions 318 of the three rear operation members 315. Due to the difference in shape (dimension), as will be described later, the developing rollers 39 of all the developing cartridges 27 are pressed against the photosensitive drum 29, or only the developing roller 39 of the black developing cartridge 27K is pressed against the photosensitive drum 29. Or the developing rollers 39 of all the developing cartridges 27 can be separated from the photosensitive drum 29.

  The four intermediate members 311 are respectively arranged on the rear side of the four operation members 315 and face the four rectangular holes 316 in the width direction. As shown in FIGS. 20 to 22, each intermediate member 311 has a substantially L shape in a side view and is formed in a block shape having a thickness in the width direction. An intermediate member support shaft 321 passes through one end portion of each intermediate member 311 in the width direction, and the intermediate member 311 is rotatably supported by the intermediate member support shaft 321. Each intermediate member 311 is in a non-contact state with the contact / separation action part 318 (see FIG. 20), and the lower end part faces the protrusion 320 of the contact / separation action part 318 with a space in the front-rear direction.

  As shown in FIG. 18, the intermediate member support shafts 321 are spaced from each other at equal intervals in the front-rear direction (same intervals as the intervals between the separation protrusions 212 when the four developing cartridges 27 are mounted on the drum unit 26). Has been placed. Each intermediate member support shaft 321 is inserted into a rectangular hole 316 opposed to the intermediate member 311 supported by the intermediate member support shaft 321 and extends outward in the width direction of the cam main body plate 314, and the inner end portion in the width direction is connected to the cam holder 312. It is supported so that it cannot rotate.

As shown in FIG. 17, the cam holder 312 includes a thin plate-like holder fixing portion 322 extending in the front-rear direction along the inner surface of the main body frame 301, and a cam housing portion 323 continuous with the lower end edge of the holder fixing portion 322. Integrated.
The holder fixing portion 322 is fixed to the inner side surface of the main body frame 301 by screws 324.

  The cam accommodating portion 323 is formed in a substantially U-shaped cross section that extends inward in the width direction from the entire length of the lower end edge of the holder fixing portion 322, bends downward, and further bends outward in the width direction. The cam housing portion 323 has a pressing protrusion receiving portion 325 that can receive the pressing protrusion 227 of the developing cartridge 27 and a separation protrusion 212 of the developing cartridge 27 by continuously cutting from the upper surface to the inner surface in the width direction. Four separate protrusion receiving portions 326 that can be received are formed alternately. That is, four pressing protrusion receiving portions 326 are formed in the cam housing portion 323 at intervals equal to the interval between the pressing protrusions 227 when the developing cartridges 27 are mounted on the drum unit 26 in the front-rear direction. Has been. In addition, four spacing protrusion receiving portions 326 are formed in the front-rear direction at intervals equal to the spacing between the spacing protrusions 212 in a state where each developing cartridge 27 is mounted on the drum unit 26. Each spacing protrusion receiving portion 326 is disposed behind each pressing protrusion receiving portion 325. In a state where the separation protrusions 212 are received by the separation protrusion receiving portions 326, the separation protrusions 212 face the intermediate members 311 from above.

The synchronous movement mechanism 313 is configured to transmit a driving force for linear movement from the left linear cam member 310 to the right linear cam member 310 in accordance with the linear movement of the left linear cam member 310. ing.
That is, as shown in FIG. 18, the synchronous movement mechanism 313 includes a left rack gear 327 formed on the upper surface of the rear end portion of the left linear cam member 310, a left pinion gear 328 meshing with the left rack gear 327, The right rack gear 329 formed on the upper surface of the rear end of the linear cam member 310, the right pinion gear 330 meshing with the right rack gear 329, and the connecting shaft 331 to which the left pinion gear 328 and the right pinion gear 330 are attached so as not to be relatively rotatable. And.

The left linear cam member 310 is provided with an input rack gear 332 to which a driving force of a motor (not shown) is input on the outer surface in the width direction of the cam body plate 314.
(4) Separation Pressing Operation The operation of the separation pressing mechanism 303 will be described mainly with reference to FIGS. 19 to 22.
As shown in FIGS. 19A and 20, in the state where the linear cam member 310 is moved to the foremost position, the contact / separation operating portion 318 of each operation member 315 and the middle disposed at the rear thereof. The member 311 is opposed to the member 311 in a non-contact state with an interval in the front-rear direction. Between the contact / separation action part 318 of the foremost operation member 315 and the intermediate member 311 arranged behind it, the contact / separation action part 318 of the rear three operation members 315 and intermediate positions arranged behind them. An interval larger than the interval between the members 311 is formed.

  In this state, each developing cartridge 27 is disposed at a contact position where the developing roller 39 and the photosensitive drum 29 are in contact with each other. The pressing action portion 317 of each operation member 315 is in contact with the pressing protrusion 227 of each developing cartridge 27 from above and presses each pressing protrusion 227 downward. When each pressing protrusion 227 is pressed downward, in each developing cartridge 27, as shown in FIG. 14, the handle 214 is rotated by using the support shaft 233 as a fulcrum, and is pressed by the handle 214 (recess 225). The contact member 217 is pushed down, and the coil spring 218 is contracted. The biasing force of the coil spring 218 due to the contraction is input to the upper wall 202 of the developing frame 36, and the developing frame 39 is biased downward, so that the developing roller 39 is pressed against the photosensitive drum 29. . At this time, the coil spring 218 generates a biasing force of 1N or more and 20N or less.

  From this state, when a driving force of a motor (not shown) is input to the input rack gear 332 and the left linear cam member 310 is moved rearward, the left pinion gear is moved along with the movement of the left linear cam member 310. 328 rotates, the rotation of the left pinion gear 328 is transmitted to the right pinion gear 330 via the connecting shaft 331, and the right pinion gear 330 rotates in the same direction as the left pinion gear 328, whereby the right linear cam member 310 moves rearward. Move to.

  When the rearward movement of the linear cam member 310 advances, the engagement between the pressing action portions 317 of the three rear operation members 315 and the pressing protrusions 227 of the developing cartridge 27 is released, and the pressing action by the pressing action portions 317 is released. The pressing of the protrusion 227 is released. Further, as shown in FIG. 19B, the contact / separation action portions 318 of the three rear operation members 315 come into contact with the lower end portions of the intermediate members 311 arranged at the rear thereof, and each intermediate member 311. The intermediate member 311 rotates so as to be lifted upward with the intermediate member support shaft 321 as a fulcrum. In the middle of the rotation of each intermediate member 311, each intermediate member 311 comes into contact with the separation protrusion 212 positioned above from below, and an upward force is applied from each intermediate member 311 to the separation protrusion 212. As a result, the yellow developing cartridge 27Y, the magenta developing cartridge 27M, and the cyan developing cartridge 27C are lifted upward.

  Then, the rearward movement of the linear cam member 310 further proceeds, and as shown in FIGS. 19C and 21, one end of the intermediate member 311 is formed on the upper surface of the contact / separation operating portion 318 of the three rear operation members 315. Portion (the end on the side through which the intermediate member support shaft 321 is inserted) abuts, the yellow developing cartridge 27Y, the magenta developing cartridge 27M, and the cyan developing cartridge 27C are arranged at the separated positions, and the yellow developing cartridge 27Y and the magenta developing. The developing rollers 39 of the cartridge 27M and the cyan developing cartridge 27C are separated from the photosensitive drum 29. At this time, the pressing protrusion 227 of the black developing cartridge 27K is pressed by the pressing action portion 317 of the operation member 315. As a result, only the developing roller 39 of the black developing cartridge 27K is pressed against the photosensitive drum 29.

  Thereafter, when the backward movement of the linear cam member 310 further proceeds, the engagement between the pressing action portion 317 of the foremost operation member 315 and the pressing protrusion 227 of the black developing cartridge 27K is released, and the pressing action portion 317 causes the engagement. The pressing of the pressing protrusion 227 is released. Further, as shown in FIG. 19D, the contact / separation action portion 318 of the foremost operation member 315 contacts the lower end portion of the intermediate member 311 disposed behind the operation member 315, and the lower end portion of the intermediate member 311 is moved rearward. The intermediate member 311 rotates so as to be lifted upward with the intermediate member support shaft 321 as a fulcrum. In the middle of the rotation of the intermediate member 311, the intermediate member 311 comes into contact with the separation protrusion 212 of the black developing cartridge 27 </ b> K positioned above from below, and an upward force is applied from the intermediate member 311 to the separation protrusion 212. As a result, the black developing cartridge 27K is lifted upward.

  Then, the rearward movement of the linear cam member 310 further proceeds, and as shown in FIGS. 19 (e) and 22, one end portion of the intermediate member 311 (on the upper surface of the contact / separation operating portion 318 of the foremost operation member 315) When the end of the intermediate member support shaft 321 is inserted, the black developing cartridge 27K is moved to the separation position, and the developing roller 39 of the black developing cartridge 27K is separated from the photosensitive drum 29. As a result, the developing rollers 39 of all the developing cartridges 27 are separated from the photosensitive drum 29.

In addition, it can return to each state shown to Fig.19 (a)-(d) by moving the linear cam member 310 ahead from the state shown in FIG.19 (e). At this time, the protrusions 320 of the contact / separation operating portions 318 are engaged with the intermediate member 311 to rotate the intermediate member 311 in the direction away from the separation protrusion 212 (downward).
5). As described above, the coil spring 218 for urging the developing roller 39 toward the photosensitive drum 29 and the handle 214 for transmitting the pressing force to the coil spring 218 via the contact member 217 are provided in the developing cartridge 27. Therefore, each time the developing cartridge 27 is replaced, the color laser printer 1 to which the developing cartridge 27 is attached can be provided with a new coil spring 218 and a handle 214. Therefore, the urging force of the coil spring 218 can be kept constant, and the good pressing state of the developing roller 39 against the photosensitive drum 29 can be kept. Further, since the developing cartridge 27 is provided with the coil spring 218, the coil spring 218 having an optimal biasing force can be disposed when the specification of the toner, the specification of the developing roller 39, or the like is changed.

In addition, since the coil spring 218 is provided on the developing frame 36 of the developing cartridge 27, the spring guide member 216 that guides the elastic deformation of the coil spring 218 can be formed integrally with the developing frame 37. Thereby, it is not necessary to provide those members on the handle 214, and the structure of the handle 214 can be simplified.
Further, the pressing protrusion 227 to which the pressing force from the separation pressing mechanism 303 is input protrudes outward in the width direction from the side wall 201, and the recess 225 for transmitting the pressing force to the coil spring 218 is inward in the width direction than the side wall 201. Therefore, the pressing force from the separation pressing mechanism 303 can be reliably received, and the pressing force can be stably transmitted to the coil spring 218.

  Further, the handle 214 can be rotated so that the handle 214 can be brought into contact with and separated from the coil spring 218 via the contact member 217. Then, with the handle 214 in contact with the contact member 217, the handle 214 is further rotated in the direction in which the coil spring 218 is compressed by the pressing force from the separation pressing mechanism 303, so that the pressing force is applied to the handle 214. Can be reliably transmitted to the coil spring 218.

  Further, since the developing cartridge 27 includes the handle 214, the developing cartridge 27 can be moved by holding the handle 214. In addition, the handle 214 also serves as a member (pressing member) for transmitting a pressing force to the coil spring 218 via the contact member 217 and the handle 214 is rotatable. The handle 214 can be rotated in the opening direction, and when used as a pressing member, the handle 214 can be rotated in the closing direction. In addition, the number of parts can be reduced as compared with the configuration in which the handle 214 and the pressing member are provided separately. Therefore, the number of parts can be reduced while the operability of the developing cartridge 27 can be improved.

  Furthermore, since the coil springs 218 are provided at two positions spaced apart in the width direction, which is the axial direction of the developing roller 39, one axial end of the developing roller 39 (rubber roller 50) is located with respect to the photosensitive drum 29. It is possible to prevent the so-called contact of the developing roller 39 with respect to the photosensitive drum 29, in which the other end is pressed relatively weakly and the other end is pressed relatively weakly against the photosensitive drum 29. Therefore, the developing roller 39 can be pressed against the photosensitive drum 29 in a balanced manner in the axial direction. As a result, the toner can be satisfactorily supplied from the developing roller 39 to the photosensitive drum 29.

  Further, the two coil springs 218 are arranged in the width direction with an interval substantially equal to the length in the width direction (the length in the axial direction) of the rubber roller 50 of the developing roller 39, and the both ends in the axial direction of the rubber roller 50. Therefore, both end portions of the rubber roller 50 in the axial direction can be reliably pressed against the photosensitive drum 29, and the developing roller 39 can be reliably prevented from coming into contact with the photosensitive drum 29. For this reason, the toner can be supplied from the developing roller 39 to the photosensitive drum 29 more satisfactorily.

In addition, since the transmission of the pressing force to the two coil springs 218 is achieved by the handle 214 constituted by one component, a component for transmitting the pressing force to each of the coil springs 218 arranged at two locations is provided separately. The number of parts can be reduced as compared with the above configuration.
Further, the spring guide member 216 guides elastic deformation of the coil spring 218. Therefore, when a pressing force is input from the handle 214 to the coil spring 218, the coil spring 218 can be elastically deformed while keeping the posture of the coil spring 218 stable. As a result, the developing roller 39 can be reliably biased toward the photosensitive drum 29.

  The coil spring 218 generates an urging force of 1N or more and 20N or less when a pressing force is input from the handle 214. If the biasing force of the coil spring 218 is 1 N or more, it is possible to prevent the developing roller 39 from hitting the photosensitive drum 29 due to insufficient biasing force. In addition, when the biasing force of the coil spring 218 is 20 N or less, the biasing force is not excessively large, and it is possible to prevent the so-called press fogging in which toner adheres to an undesired region of the photosensitive drum 29.

  Furthermore, by changing the strength of the coil spring 218 for each developing cartridge 27, an appropriate urging force can be set according to the type (color) of the toner stored in the toner storage chamber 43. Thus, the developing roller 39 can be pressed against the photosensitive drum 29 satisfactorily. Therefore, it is possible to satisfactorily supply the corresponding color toner to each photosensitive drum 29.

  Further, the developing roller 39 is disposed at the lower end of the developing cartridge 27, and the developing roller 39 is pressed against the photosensitive drum 29 from above, so that the weight of the developing cartridge 27 is applied to the pressing of the developing roller 39 against the photosensitive drum 29. Works. Therefore, if the toner amount stored in the toner storage chamber 43 and the design of the developing frame 36 are changed, and the weight of the developing cartridge 27 changes, the pressing state of the developing roller 39 against the photosensitive drum 29 changes. In this embodiment, since the developing cartridge 27 is provided with the coil spring 218, even if the weight of the developing cartridge 27 is changed, the developing roller 39 is moved to the photosensitive drum 29 by adjusting the biasing force of the coil spring 218. On the other hand, it can be pressed in a predetermined pressing state.

  In addition, since the handle 214 is provided so as to be rotatable between a standing state and a tilted state, when the drum unit 26 is mounted on the main body casing 2, an obstacle (for example, a main body) is placed on the movement path of the standing handle 214. Even if the component 2 of the casing 2 is present, the handle 214 in the standing state rotates from the standing state to the tilted state due to the collision with the obstacle. Therefore, it is possible to prevent the handle 214 from obstructing the mounting of the drum unit 26, and to ensure a smooth mounting of the drum unit 26 to the main body casing 2.

  Since the color laser printer 1 includes the developing cartridge 27 that can keep the pressing state of the developing roller 39 against the photosensitive drum 29, the toner from the developing roller 39 to the photosensitive drum 29 is excellent. Supply can be secured. Therefore, it is possible to achieve a good visible image of the electrostatic latent image formed on the photosensitive drum 29, and it is possible to form a high quality image.

Further, since the drum unit 26 can be attached to and detached from the main casing 2, maintenance work such as jam processing and parts replacement can be easily performed. In addition, since the developing cartridge 27 can be replaced individually, the cost for maintenance (maintenance cost) can be reduced.
6). Other Embodiments of Developing Cartridge FIG. 23 is a perspective view showing another embodiment of the developing cartridge 27. In FIG. 23, portions corresponding to the above-described portions are denoted by the same reference numerals as those portions. Further, in the following, detailed description of each part given the same reference numeral is omitted.

In the developing cartridge 27 according to this embodiment, the handle 214 is not provided, and a leaf spring member 401 as an example of a pressing member is provided at both ends in the width direction on the upper wall 202 of the developing frame 36. .
One end portion 402 of the leaf spring member 401 as an example of an urging portion is fixed to the upper surface of the upper wall 202 by a screw 403. The leaf spring member 401 is bent upward from the one end portion 402, further bent outward in the width direction, and extends outward in the width direction. The other end portion 404 of the leaf spring member 401 protrudes outward in the width direction from the side wall 201 of the developing frame 36 to form a protruding portion to which the pressing force from the pressing action portion 317 of the separation pressing mechanism 303 is input. ing.

Even in such a configuration, when the pressing action portion 317 of the separation pressing mechanism 303 comes into contact with the other end portion 404 of the leaf spring member 401 from above and presses the other end portion 404 downward, the leaf spring member 401 is moved. The urging force of the leaf spring member 401 due to the elastic deformation is input to the upper wall 202 of the developing frame 36, and the developing frame 36 is urged downward, whereby the developing roller 39 is applied to the photosensitive drum 29. Pressed. Therefore, the same effect as the developing cartridge 27 shown in FIG. 6 can be obtained.
7). Other Embodiments of Developing Cartridge FIGS. 24 and 25 are perspective views showing other embodiments of the developing cartridge 27. In FIG. 24 and FIG. 25, the same reference numerals are assigned to the parts corresponding to the above-described parts. Further, in the following, detailed description of each part given the same reference numeral is omitted.

In the developing cartridge 27 according to this embodiment, the spring guide member 216, the contact member 217, and the coil spring 218 are not provided, and the width direction of the front end portion of the upper wall 202 as an example of the end surface of the developing frame 36 is not provided. A prismatic elastic member 411 made of an elastic material such as sponge or rubber is provided over the entire width (in the axial direction of the developing roller 39).
Even in such a configuration, when the pressing action portion 317 of the separation pressing mechanism 303 comes into contact with the pressing protrusion 227 of the developing cartridge 27 from above and presses each pressing protrusion 227 downward, the handle 214 is tilted. The elastic member 411 is pressed by the handle 214, and the elastic member 411 contracts. The urging force of the elastic member 411 due to the contraction is input to the upper wall 202 of the developing frame 36, and the developing frame 39 is urged downward, whereby the developing roller 39 is pressed against the photosensitive drum 29. Therefore, the same effect as the developing cartridge 27 shown in FIG. 6 can be obtained.

In addition, an urging force can be applied from the elastic member 411 to the entire axial width of the upper wall 202, and the developing roller 39 can be urged toward the photosensitive drum 29 by the urging force. Therefore, the developing roller 39 can be pressed against the photosensitive drum 29 in a balanced manner in the axial direction. As a result, the toner can be satisfactorily supplied from the developing roller 39 to the photosensitive drum 29.
8). Other Embodiments of Developing Cartridge FIGS. 26 and 27 are perspective views showing other embodiments of the developing cartridge 27. FIG. 28 is a perspective view of the upper left portion of the developing cartridge 27 shown in FIG. In FIG. 26, FIG. 27 and FIG. 28, portions corresponding to the above-described portions are denoted by the same reference numerals as those portions. Further, in the following, detailed description of each part given the same reference numeral is omitted.

  In the developing cartridge 27 according to this embodiment, the handle 214 is not provided, and the upper wall 202 of the developing frame 36 is pressed toward both ends in the width direction of the front end portion thereof to protrude outward in the width direction. A protrusion 421 is provided. The pressing protrusion 421 is formed integrally with the developing frame 36. A cylindrical elastic ring 422 made of an elastic material such as sponge or rubber is attached to the tip of the pressing protrusion 421.

In such a configuration, a portion where the elastic ring 422 of the pressing protrusion 421 is attached is received by the pressing protrusion receiving portion 325 (see FIG. 16). When the pressing action portion 317 of the separation pressing mechanism 303 comes into contact with the elastic ring 422 from above and presses the elastic ring 422 downward, the elastic ring 422 is elastically deformed, and the elastic ring 422 is caused by the elastic deformation. The urging force is input to the pressing protrusion 421 and the developing frame 36 is urged downward, whereby the developing roller 39 is pressed against the photosensitive drum 29. Therefore, the same effect as the developing cartridge 27 shown in FIG. 6 can be obtained.
9. Other Embodiments of Developing Cartridge FIGS. 29 and 30 are perspective views of another embodiment of the developing cartridge 27 as seen from the left front. FIG. 31 is a front view of the developing cartridge 27 as viewed from the front, and FIG. 32 is a cross-sectional view taken along a cutting line BB shown in FIG. 29 to 32, parts corresponding to the above-described parts are denoted by the same reference numerals as those parts. Further, in the following, detailed description of each part given the same reference numeral is omitted.

In the developing cartridge 27 described above, as shown in FIG. 9, two spring guide members 216 are provided on the upper wall 202 of the developing frame 36. A recess 225 that can receive the corresponding contact member 217 is formed on the lower surface of the handle 214 at a position corresponding to each contact member 217.
On the other hand, in this developing cartridge 27, as shown in FIG. 30, a cylindrical spring guide member 216 is provided in each recess 225 formed on the lower surface of the handle 214. As shown in FIGS. 29 to 31, the top end portion 401 of the main body 219 of the corresponding contact member 217 is received on the upper wall 202 of the developing frame 36 at a position corresponding to each contact member 217. A possible receiving groove 402 is formed.

More specifically, each spring guide member 216 is formed integrally with the handle 214. The distal end portion of each spring guide member 216 protrudes out of the recess 225. On the peripheral surface of each spring guide member 216, a plurality of groove portions 223 extending in the central axis direction are formed from the edge on the handle 214 side to the middle portion in the central axis direction.
As shown in FIG. 32, the contact member 217 is provided in a state in which each locking claw portion 222 is locked to the groove portion 223 of the spring guide member 216 and the main body portion 219 protrudes from the guide member 216. The front end 401 of the main body 219 has a substantially semicircular shape when viewed from the side, and is formed in a rib shape extending in the front-rear direction.

The coil spring 218 is provided in a compressed state between the lower surface of the handle 214 and the abutting member 217, and urges the abutting member 217 in a direction to be removed from the spring guide member 216.
When the handle 214 is tilted to the tilted state, the leading end portions 401 of the contact members 217 are received in the receiving grooves 402, and the leading end portions 401 are the bottom surfaces of the receiving grooves 402 (the upper wall 202 of the developing frame 36). Abut. When the handle 214 is rotated from the tilted state to the pressed state, each contact member 217 is pressed toward the handle 214 and each coil spring 218 is compressed. Then, the urging force of each coil spring 218 due to the compression is input from each contact member 217 to the upper wall 202 of the developing frame 36, and the developing frame 36 is urged downward, whereby the developing roller 39 is moved. The photosensitive drum 29 is pressed.

  Thus, the spring guide member 216, the contact member 217, and the coil spring 218 may be provided on the handle 214. By adopting this configuration, it is possible to eliminate the necessity of providing these members on the development frame 36, and to simplify the configuration of the development frame 36.

DESCRIPTION OF SYMBOLS 1 Color laser printer 2 Main body casing 26 Drum unit 27 Developing cartridge 29 Photosensitive drum 36 Developing frame 39 Developing roller 201 Side wall 202 Upper wall 214 Handle 216 Spring guide member 218 Coil spring 225 Concavity 227 Pressing protrusion 310 Direct acting cam member

Claims (9)

A developer carrier for supplying a developer to an image carrier on which an electrostatic latent image is formed to visualize the electrostatic latent image; and
A housing that contains a developer and has a developer carrier support portion on one side end on which the developer carrier is supported;
The other end of the housing opposite to the developer carrier support portion is provided to be rotatable about a rotation axis extending in the axial direction of the developer carrier, and more than the housing. A protruding portion that protrudes outward in the axial direction of the developer carrying member and receives a pressing force from the outside, and an interval in the axial direction that is inward in the axial direction from the side surface in the axial direction of the housing And a biasing portion that biases the housing in a direction in which the developer carrier is pressed against the image carrier when a pressing force is input to the protrusion. And a pressing member that is rotated by the pressing force and presses the housing in a direction in which the developer carrier is pressed against the image carrier via the biasing portion. A developing cartridge.   The developing cartridge according to claim 1, wherein the pressing member also serves as a handle that is gripped when the developing cartridge is moved.   The developing cartridge according to claim 1, further comprising a guide member that is provided on the pressing member and guides elastic deformation of the urging portion due to the pressing force.   The developing cartridge according to claim 1, wherein the urging unit generates an urging force of 1 N or more and 20 N or less.   5. The developing cartridge according to claim 1, wherein the developing cartridge is used in a color image forming apparatus including a plurality of the image carriers provided corresponding to the respective colors. 6.   The developing cartridge is disposed in the color image forming apparatus such that the one end of the casing is positioned relatively downward and the other end of the casing is positioned relatively upward. The developing cartridge according to claim 5, wherein The color image forming apparatus includes an apparatus main body and an image carrier unit that is detachably attached to the apparatus main body and integrally holds a plurality of the image carriers.
The developing cartridge is detachably attached to the image carrier unit,
The pressing member is in an upright state intersecting with the attaching / detaching direction about a rotation axis extending in a direction intersecting with the attaching / detaching direction of the image carrier unit in a state where the developing cartridge is mounted on the image carrier unit. 7. The developing cartridge according to claim 5, wherein the developing cartridge is rotatably provided in a tilted state in which the image carrier unit is tilted to an upstream side in a moving direction when the image carrier unit is mounted. A developing cartridge according to any one of claims 1 to 7,
An image forming apparatus comprising: a pressing force input member that inputs a pressing force to the pressing member. The device body;
An image carrier unit that is detachably attached to the apparatus main body and integrally holds a plurality of image carriers,
9. The image forming apparatus according to claim 8, wherein the developing cartridge is detachably attached to the image carrier unit.

Images