JP2009025830A - Photoreceptor cartridge, developing cartridge and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus provided with a first cartridge and a second cartridge which are freely attachable/detachable, saving space in attaching/detaching paths for them, obtaining reduced size for the apparatus and to provide a photoreceptor cartridge, a developing cartridge and a process cartridge which are freely attached/detached to the image forming apparatus. <P>SOLUTION: A scanner casing 35 is arranged so as to expand out toward the front from a partition plate 10 in a process storing part 12 to which the drum cartridge 31 and the developing cartridge 32 are attached. The scanner casing 35 is formed so that passage of the drum cartridge 31 in a developer storing part 14 is restricted while the developer cartridge 32 is attached to the drum cartridge 31 and passage of the drum cartridge 31, and is allowed in a developing storing space 16 while the developing cartridge 32 is separated from the drum cartridge 31 in the developer storing part 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photosensitive cartridge, a developing cartridge, and a process cartridge that are detachably attached to an image forming apparatus such as a laser printer.

2. Description of the Related Art In recent years, electrophotographic image forming apparatuses are known in which a developing device and a photosensitive member are accommodated in separate cartridges, and only necessary cartridges can be replaced in accordance with the life of each cartridge.
For example, a photosensitive cartridge including a photosensitive drum and a developing cartridge including a developing roller are provided, and the photosensitive cartridge and the developing cartridge can be integrally attached to and detached from the main body casing (see, for example, Patent Document 1). It is known that the photosensitive cartridge and the developing cartridge can be attached to and detached from the main body casing through independent paths (see, for example, Patent Document 2).
JP 2000-267371 A JP 2003-287992 A

However, in any of the image forming apparatuses including the photosensitive cartridge and the developing cartridge described above, a space obtained by simply adding the photosensitive cartridge attaching / detaching path and the developing cartridge attaching / detaching path is required in the main body casing. For this reason, there is a limit to downsizing the apparatus.
SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive cartridge, a developing cartridge, and a process cartridge that are detachably attached to an image forming apparatus, can save space in the attaching / detaching path, and can achieve downsizing of the image forming apparatus. There is to do.

  In order to achieve the above object, the invention described in claim 1 includes a first housing, a photoconductor and a charger provided in the first housing, and is detachable from a cartridge housing portion of the image forming apparatus. In the mounted photosensitive cartridge, the first housing integrally includes a main body portion that houses the charger and the photosensitive member, and an extending portion that is disposed on the downstream side in the mounting direction with respect to the main body portion. It is characterized by having.

According to such a configuration, since the main body portion and the extending portion are integrally formed, the configuration can be simplified. In addition, the positioning accuracy of the photoreceptor and the charger can be improved.
According to a second aspect of the present invention, in the first aspect of the present invention, the main body portion is formed thicker than the extending portion in a thickness direction perpendicular to the mounting direction of the photosensitive cartridge. It is characterized by that.

According to such a configuration, the main body portion is formed thicker than the extending portion in the thickness direction orthogonal to the mounting direction of the photosensitive cartridge, so that the photoconductor and the charger can be reliably accommodated.
According to a third aspect of the present invention, in the first or second aspect of the present invention, the first housing has a protrusion projecting outwardly from the cartridge accommodating portion of the photosensitive cartridge. In some cases, the first housing is provided so as to prevent rubbing against the cartridge housing portion.

According to such a configuration, when the photosensitive cartridge is attached / detached, the protrusions prevent sliding against the bulging portion of the first casing, so that the first casing can be prevented from being damaged when the photosensitive cartridge is attached / detached. .
According to a fourth aspect of the present invention, in the third aspect of the present invention, the protrusion is provided on the main body portion of the first housing and further on the downstream side in the mounting direction of the photosensitive cartridge than the charger. It is characterized by being provided.

According to such a configuration, since the protrusion is provided on the downstream side in the mounting direction of the photosensitive cartridge from the charger in the main body portion of the first housing, the protrusion is always charged when the photosensitive cartridge is mounted. Located in front of. Therefore, damage to the charger can be reliably prevented.
According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the extending portion of the first housing is spaced apart along the mounting direction of the photosensitive cartridge. Extending side portions extending so as to face each other are provided, and each extending side portion is provided with a reinforcing portion for reinforcing each extending side portion along the mounting direction of the photosensitive cartridge. It is characterized by having.

According to such a configuration, the extending side portions of the extending portion extend so as to face each other with a gap therebetween, so that interference with the cartridge housing portion can be reduced. Moreover, since the reinforcement part is formed in the extension side part, the intensity | strength of the extension side part can be improved.
According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the extension portion of the first housing is operated to attach / detach the photosensitive cartridge to / from the cartridge housing portion. It is characterized in that a gripping part is provided.

According to such a configuration, the operability can be improved by gripping the grip portion and operating the attachment / detachment of the photosensitive cartridge with respect to the first storage portion.
According to a seventh aspect of the invention, in the sixth aspect of the invention, the first casing is an extended end that connects upstream ends of the extending side portions in the mounting direction of the photosensitive cartridge. It is characterized by the above-mentioned. The grip part is provided in the extension end part.

According to such a configuration, since the grip portion is provided at the extended end portion that connects the respective extended side portions, the grip portion can be easily gripped, and the operability can be further improved.
The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the first casing can be mounted with a developing cartridge including a developing roller, and the first casing is The charger, the photoconductor, and the developing cartridge are positioned.

According to such a configuration, since the first casing positions the charger, the photoconductor, and the developing cartridge, the relative positioning accuracy can be improved with a simple configuration.
The invention described in claim 9 is characterized in that, in the invention described in claim 8, the first housing positions the developing cartridge with reference to an axis of the developing roller.

According to such a configuration, the developing cartridge is positioned in the first housing with reference to the axis of the developing roller. Therefore, it is possible to improve the positioning accuracy of the developing roller with respect to the photoconductor.
The invention according to claim 10 is the invention according to any one of claims 5 to 9, wherein the first casing is surrounded by a main body portion, the extension side portions, and the extension end portion. An opening for allowing the laser beam toward the photosensitive member to pass therethrough is formed in the portion to be provided.

According to such a configuration, it is possible to ensure the reliable passage of the laser light toward the photosensitive member from the opening formed in the portion surrounded by the main body portion, each extending side portion, and the extending end portion.
The invention according to claim 11 is a process cartridge, which is provided in the photosensitive cartridge according to any one of claims 1 to 10, the second casing, and the second casing, and a part thereof. And the developing roller disposed so as to be exposed from the second casing, and a developing cartridge that is detachably mounted in a cartridge housing portion of the image forming apparatus.

According to such a configuration, since the photosensitive cartridge with good positioning accuracy is provided, a reliable operation can be ensured.
The invention according to claim 12 includes a second casing, and the developing roller provided in the second casing and arranged so that a part thereof is exposed from the second casing, In the developing cartridge that is detachably mounted in the cartridge housing portion of the image forming apparatus, the bulge is provided on the peripheral surface exposed to the developing roller along the longitudinal direction of the developing roller. A pressure-contact portion that is disposed opposite to the opposite portion and is pressed against the peripheral surface to prevent developer leakage, and contacts the cartridge housing portion before the pressure-contact portion when the developer cartridge is mounted. And is provided with a rubbing portion that rubs against the cartridge housing portion.

According to such a configuration, when the developing cartridge is mounted, the rubbing portion comes into contact with the cartridge housing portion and rubs before the press contact portion. Therefore, damage to the pressure contact portion can be prevented, and developer leakage from the peripheral surface of the developing roller can be reliably prevented.
A process cartridge according to a thirteenth aspect of the present invention is a process cartridge including a first housing, a photoconductor and a charger provided in the first housing, and is detachable from a cartridge housing portion of the image forming apparatus. And a developing cartridge according to a twelfth aspect of the present invention.

  According to such a configuration, since the developing cartridge in which leakage of the developer is reliably prevented is provided, a reliable operation can be ensured.

According to the first aspect of the present invention, it is possible to simplify the configuration and improve the positioning accuracy of the photosensitive member and the charger.
According to the second aspect of the present invention, the photosensitive member and the charger can be reliably accommodated.

According to the third aspect of the present invention, it is possible to prevent the first casing from being damaged when the photosensitive cartridge is attached or detached.
According to the fourth aspect of the present invention, damage to the charger can be reliably prevented.
According to the fifth aspect of the present invention, interference with the cartridge housing portion can be reduced. Further, the strength of the extending side portion can be improved.

According to the invention described in claim 6, the operability of the photosensitive cartridge can be improved.
According to the seventh aspect of the present invention, the grip portion can be easily gripped, and the operability can be further improved.
According to the eighth aspect of the present invention, it is possible to improve the relative positioning accuracy of the charger, the photosensitive member, and the developing cartridge with a simple configuration.

According to the ninth aspect of the present invention, it is possible to improve the positioning accuracy of the developing roller with respect to the photosensitive member.
According to the tenth aspect of the present invention, it is possible to ensure the reliable passage of the laser beam toward the photosensitive member.
According to the invention of claim 11, it is possible to ensure a reliable operation.

According to the twelfth aspect of the present invention, it is possible to prevent the press contact portion from being damaged, and to reliably prevent the leakage of the developer from the peripheral surface of the developing roller.
According to the thirteenth aspect of the present invention, a reliable operation can be ensured.

FIG. 1 is a cross-sectional side view of an essential part showing an embodiment of a color laser printer as an image forming apparatus of the present invention.
In FIG. 1, the color laser printer 1 is a horizontal type tandem color laser printer in which a plurality of process units 27 are arranged in parallel in a horizontal direction, and a sheet 3 is placed in a main body casing 2. A paper feed unit 4 for feeding paper, an image forming unit 5 for forming an image on the fed paper 3, and a paper discharge unit 6 for discharging the paper 3 on which the image is formed are provided.

  The main casing 2 has a box-like shape that is substantially rectangular in a side view with the upper side opened, and a top cover 7 is provided on the upper side. The top cover 7 is rotatable via a hinge (not shown) provided on the rear side of the main casing 2 (in the following description, the left side in FIG. 1 is the rear side and the right side is the front side). The main casing 2 is supported so that it can be opened and closed.

  Further, as shown in FIG. 14, the main casing 2 includes a left side plate 8 and a right side plate 9 that are opposed to each other with a space therebetween in the width direction (the front-rear direction and the direction orthogonal to the vertical direction, hereinafter the same). The partition plate 10 and the front plate 11 are provided as a plurality of (four) second positioning portions that are installed between them. Each partition plate 10 and front plate 11 are arranged in the middle of the main casing 2 in the front-rear direction so as to partition the front-rear space between the left side plate 8 and the right side plate 9 for each process unit 27 described later. The front plate 11 is provided at a distance from each other, and the front plate 11 is provided in front of each partition plate 10.

  Each of the partition plates 10 and the front plate 11 is inclined such that the upper end portion is the front side and the lower end portion is the rear side with respect to the front-rear direction (the same as the conveyance direction of the paper 3 at the image forming position described later) and the vertical direction. Are arranged as follows. Further, as shown in FIG. 1, the partition plates 10 and the front plate 11 are arranged such that their upper end portions are spaced apart from the top cover 7 in the vertical direction, and lower end portions thereof are arranged vertically with a transfer portion 28 described later. It arrange | positions so that the space | interval may be separated in the direction.

In the main casing 2, the partition plates 10 and the front plate 11 that are adjacent to each other, and the left side plate 8 and the right side plate 9 are used as a plurality (four pieces) of cartridge storage units in which the process units 27 for each color are arranged. ) Of the process container 12 is partitioned.
Each process accommodating portion 12 accommodates a drum cartridge 31 to be described later and a developing cartridge 32 to be described later. And a developing container 14 as a second container in which the cartridge 32 is mounted.

  The drum accommodating portion 13 is provided below the respective partition plates 10, and in the front-rear direction, each of the partition plates 10 and the front plate 11 is partitioned by a virtual extension plane that extends as it is downward in the tilt direction, and in the width direction. The left side plate 8 and the right side plate 9 are partitioned. The internal space partitioned by them is a drum housing space 15 as a first housing region for housing a holder portion 43 of the drum cartridge 31 described later.

  Further, the developing container 14 is mounted upstream of the drum cartridge 31 to be described later with respect to the drum container 13, that is, on the upstream side of the drum container 13. And is partitioned by the partition plates 10 and the front plate 11 in the front-rear direction and by the left side plate 8 and the right side plate 9 in the width direction. An internal space partitioned by them (excluding an extended portion accommodating space 18 described later) is a developing accommodating space 16 as a second accommodating region for accommodating a developing cartridge 32 described later. .

Further, as shown in FIG. 14, the developing accommodating portion 14 is provided with rail portions 17 that rub against each of the horn portions 51 of the drum cartridge 31 described later at both ends in the width direction of the partition plate 10. Each rail portion 17 is formed in a strip shape having a thickness along the attaching / detaching direction of the drum cartridge 31.
As shown in FIG. 1, the paper feed unit 4 includes a paper feed tray 21 that is detachably attached to the main body casing 2 from the front side in the horizontal direction at the bottom of the main body casing 2, and the paper feed tray 21. Pickup roller 22 and paper feed roller 23 as supply means provided above the front side, paper feed side U-shaped path 24 provided above the front side of paper feed roller 23, and midway of paper feed side U-shaped path 24. A conveyance roller 25 and a registration roller 26 are provided.

The paper 3 is stacked in the paper feed tray 21, and the paper 3 at the top is first picked up by the pickup roller 22 and conveyed forward, and then fed by the paper feed roller 23. Paper is fed to the U-shaped path 24.
The feed-side U-shaped path 24 has an upstream end adjacent to the feed roller 23 at the lower side and a downstream end at the upper side so that the sheet 3 is fed forward. Adjacent to the belt 80, it is formed as a conveyance path for the substantially U-shaped sheet 3 so that the sheet 3 is discharged rearward.

The paper 3 fed forward by the paper feed roller 23 to the upstream end of the paper feed side U-shaped path 24 is transported by the transport roller 25 in the paper feed side U-shaped path 24. Then, the conveying direction is reversed, and after registration, the paper is discharged backward by the registration roller 26.
The image forming unit 5 includes a process unit 27, a transfer unit 28, and a fixing unit 29. The process unit 27 is provided for each color of a plurality of colors of toner. In other words, the process unit 27 includes four units, that is, a yellow process unit 27Y, a magenta process unit 27M, a cyan process unit 27C, and a black process unit 27K. These process units 27 are arranged in the respective process accommodating units 12 of the main casing 2 and are sequentially arranged in parallel so as to be overlapped in the horizontal direction at intervals from the front to the rear.

  Each process unit 27 includes a scanner unit 30, a drum cartridge 31 that is a photosensitive cartridge as a first cartridge, and a developing cartridge 32 included in a process cartridge as a second cartridge that is detachably attached to the drum cartridge 31. And. The drum cartridge 31 and the developing cartridge 32 attached to the drum cartridge 31 constitute a process cartridge.

The scanner unit 30 includes a scanner casing 35 as a bulging part, and a laser light emitting part (not shown), a polygon mirror 36, two lenses 37 and 38, and a reflecting mirror 39 in the scanner casing 35. Yes.
As shown in FIG. 14, the scanner casing 35 is disposed at the center in the width direction of each partition plate 10 such that each rail portion 17 faces the scanner casing 35 across the width direction. The rear wall is in contact with the front surface of the partition plate 10, and the front wall 34 of the scanner casing 35 is provided on each partition plate 10 so as to bulge forward from the partition plate 10. Thus, since the scanner casing 35 is arranged so as to bulge forward from the partition plate 10, the scanner unit 30, the drum cartridge 31, and the developing cartridge 32 can be arranged close to each other. Therefore, the apparatus can be reduced in size.

  Further, since the scanner casing 35 is arranged so as to bulge forward from the partition plate 10 in this way, in the developing container 14, in the state where the developing cartridge 32 is mounted on the drum cartridge 31, the developing cartridge 32 is developed. In the state where the passage of the drum cartridge 31 in the housing portion 14 is restricted and the developing cartridge 32 is separated from the drum cartridge 31, the passage of the drum cartridge 31 in the developing housing space 16 is allowed in the developing housing portion 14. become.

That is, as shown in FIG. 15, the developing container 14 is moved by the scanner casing 35 in a direction orthogonal to the mounting direction and the width direction of the drum cartridge 31 and the developing cartridge 32 (the thickness of the mounted drum cartridge 31 and the developing cartridge 32. In the vertical direction, hereinafter simply referred to as “thickness direction”), it is formed narrower than the drum accommodating portion 13.
More specifically, the developing container 14 is wider in the thickness direction than a holder 43 of the drum cartridge 31 described later, and is housed in the process container 12 and is in a mounted state. Further, the developing cartridge 32 is formed to be narrower than the thickness thereof.

  Further, since the drum accommodating portion 13 is secured on the upstream side in the mounting direction of the drum cartridge 31 from the scanner casing 35, an enlarged space 19 is secured as an enlarged region that is wider than the developing accommodating portion 14, so that in the thickness direction, It is formed wider than the thickness of the drum cartridge 31 and the developing cartridge 32 that are accommodated in the process accommodating portion 12 and are attached to each other.

  Therefore, as will be described later, the drum cartridge 31 is in a state in which the holder portion 43 is disposed in the enlarged space 19, that is, the drum cartridge 31 is accommodated in the drum accommodating space 15 of the drum accommodating portion 13, and the developing cartridge 32 is accommodated in developing. In the state of being accommodated in the developer accommodating space 16 of the portion 14, even if the drum cartridge 31 is to be detached, the holder portion 43 and the scanner casing 35 come into contact with each other, and the movement of the drum cartridge 31 in the removal direction is restricted. The Then, after the developing cartridge 32 is detached from the developing container 14, the drum cartridge 31 is shifted in a direction (front) away from the scanner casing 35 by a distance corresponding to the thickness of the developing cartridge 32. Accordingly, the drum cartridge 31 can be detached from the drum accommodating portion 13 through the developing accommodating portion 14.

  In addition, the width and both sides of the scanner casing 35 in the width direction and the upper side of the developer accommodating portion 14 and the vicinity of the front wall 34 of the scanner casing 35 (between the front wall 34 of the scanner casing 35 and the developer accommodating space 16, which will be described later) In the space in which the plate 54 is disposed, an extension portion accommodation space 18 is formed as an extension portion accommodation area in which an extension portion 44 (described later) of the drum cartridge 31 is accommodated.

Further, as shown in FIG. 1, an emission window 40 for emitting laser light is opened in the front wall 34 of the scanner casing 35.
In the scanner unit 30, the laser light based on the image data emitted from the laser light emitting unit is reflected by the polygon mirror 36, and sequentially passes or reflects through the lens 37, the reflecting mirror 39, and the lens 38, and the exit window 40. It is emitted from.

As shown in FIGS. 2 and 3, the drum cartridge 31 includes a drum casing 41 as a first casing, a photosensitive drum 42 as a process member provided in the drum casing 41, and a charger. And a scorotron charger 62 (see FIG. 1).
The drum casing 41 includes a holder portion 43 that is a protruding portion serving as a main body portion, and an extending portion 44 that extends from the holder portion 43, and is integrally formed from a resin material.

  In the description of the drum cartridge 31 with reference to FIGS. 2 to 7, the upper side of the sheet is “upper” (the rear side when the drum cartridge 31 is mounted), and the lower side of the sheet is “lower” (when the drum cartridge 31 is mounted). The side on which the holder portion 43 is disposed is “front side” (lower side when the drum cartridge 31 is mounted), and the side on which the extension portion 44 is disposed is “rear side” (when the drum cartridge 31 is mounted). Upper side).

The holder portion 43 includes two holder side walls 45 arranged to face each other at an interval in the width direction, a holder upper wall 46 installed on the upper end portion of each holder side wall 45, and each holder from the front end portion of the holder upper wall 46. A holder front wall 47 provided halfway in the vertical direction of the side wall 45 is provided.
Note that the thickness (length in the vertical direction) of the holder portion 43 is formed to be greater than the thickness (length in the vertical direction) of the developing case 64 of the developing cartridge 32.

Further, the thickness (vertical length) of the holder portion 43 is formed to be thicker than the thickness (vertical length) of the extending portion 44. By forming the holder portion 43 to be thicker than the extending portion 44, the photosensitive drum 42 and the scorotron charger 62 can be reliably accommodated.
As shown in FIGS. 6 and 7, each holder side wall 45 is formed with a substantially U-shaped development positioning groove 48 opened rearward in the lower portion thereof. Further, an insertion portion 49 through which the drum shaft 60 of the photosensitive drum 42 is inserted is formed in front of the development positioning groove 48.

As shown in FIG. 2, the holder upper wall 46 is formed with a cleaner fitting portion 50 in which a cleaner 63 described later is slidably fitted over the width direction. Further, as shown in FIGS. 6 and 7, at both ends in the width direction of the holder upper wall 46, horn portions 51 are formed as protrusions having a substantially triangular shape in a side view protruding upward at the front end portion. Yes.
As shown in FIGS. 2 and 3, the extending portion 44 extends above the upper end portion of the scanner casing 35 in the developing housing portion 14 in a state where the holder portion 43 is attached to the drum housing portion 13. In addition, it extends rearward from the holder portion 43.

The extending portion 44 includes two extending side portions 52 that are opposed to each other with an interval in the width direction, and an extending rear wall that is extended to the rear end portion of each extending side portion 52. 53, and an intermediate plate 54 provided in a portion surrounded by the holder portion 43, each extending side portion 52, and the extending rear wall 53.
As shown in FIG. 2, each extending side portion 52 has a substantially U-shaped cross-section with its lower portion opened, and each outer surface is continuously rearward from the upper portion of the development positioning groove 48 of each holder side wall 45. The holder part 43 is formed so as to extend rearward from both sides in the width direction.

Further, as shown in FIG. 3, each extension side portion 52 is provided with two reinforcing ribs 55 along the front-rear direction inside the U-shaped inside as a reinforcing portion that is substantially X-shaped when viewed from the bottom. It has been.
In addition, a drum boss portion 56 that protrudes outward in the width direction is provided on the outer surface of each extending side portion 52 in the middle of the longitudinal direction.
The extended rear wall 53 extends along the width direction so as to connect the rear end portions of the extended side portions 52, and the drum cartridge 31 is gripped at the center portion in the width direction. A drum handle 57 is provided as a gripping part for operating attachment / detachment with respect to the housing part 13.

  The intermediate plate 54 has a substantially rectangular flat plate shape in a plan view, and as shown in FIG. 2, each extended side portion 52 is surrounded by the holder portion 43, each extended side portion 52, and the extended rear wall 53. And it is provided so that it may connect with the holder part 43, each extension side part 52, and the extension rear wall 53 in the position dented below from the upper surface of the extension rear wall 53. As shown in FIG. The middle plate 54 is formed with an opening 58 for allowing laser light emitted from the emission window 40 of the scanner casing 35 to pass therethrough. As shown in FIG. 4, the opening 58 is formed in a trapezoidal shape in plan view with a wide front side and a narrow rear side. If the opening 58 is formed in a trapezoidal shape in plan view in this way, only the laser beam transmitting portion in the intermediate plate 54 is cut out, and the strength of the extension 44 is higher than that in the rectangular shape in plan view. Can be high.

  As shown in FIG. 2, the photosensitive drum 42 is accommodated in the holder portion 43 along the width direction. The photosensitive drum 42 has a cylindrical shape, and a drum main body 59 formed by a positively chargeable photosensitive layer whose outermost layer is made of polycarbonate or the like, and an axial center of the drum main body 59 along the axial direction of the drum main body 59. And a drum shaft 60 as a support shaft. The drum shaft 60 is supported at each holder side wall 45 so as not to rotate so that both end portions in the axial direction are inserted into the insertion portions 49 of the holder side walls 45 and protrude outward in the width direction of the holder side walls 45. .

  At both ends in the axial direction of the drum main body 59, rotation support members 61 are fitted so as not to be relatively rotatable, and each rotation support member 61 is supported around the drum shaft 60 so as to be relatively rotatable. Thereby, the drum main body 59 is rotatably supported with respect to the drum shaft 60. In this state, as shown in FIG. 5, the photosensitive drum 42 is arranged in the holder portion 43 so that the front surface is exposed from below the holder front wall 47.

  As shown in FIG. 1, the scorotron charger 62 is accommodated in the holder portion 43 along the width direction above the horn portion 51 (backward in FIG. 2). The scorotron charger 62 is a positively charged scorotron charger that includes a wire and a grid and generates corona discharge. The scorotron charger 62 is supported by the holder upper wall 46 behind the photosensitive drum 42 (upward in FIG. 2). In other words, they are arranged opposite to each other so as not to contact the photosensitive drum 62. Further, as shown in FIG. 2, the scorotron charger 93 is provided with a cleaner 63 for cleaning the wire so as to be slidably fitted to the cleaner fitting portion 50 of the holder upper wall 46. ing.

As shown in FIGS. 8 and 9, the developing cartridge 32 includes a developing housing 64 as a second housing and a toner housing chamber 65 (a developer housing portion as a process member provided in the developing housing 64 ( 1), a supply roller 66 (see FIG. 1), a developing roller 67 as a developer carrier, and a layer thickness regulating blade 68.
In the description of the developing cartridge 32 with reference to FIGS. 8 to 13, the upper side of the sheet is “upper” (the rear side when the developing cartridge 32 is mounted), and the lower side of the sheet is “lower” (when the developing cartridge 32 is mounted). The front side of the developing roller 67 is “front side” (lower side when the developing cartridge 32 is mounted), and the side where the toner container 65 is positioned is “rear side” (when the developing cartridge 32 is mounted). Upper side).

As shown in FIG. 8, the developing case 64 is formed in a box shape whose front side is opened. At the lower front end portion of the developing case 64, an jaw portion 69 as a pressure contact portion and a warp portion 70 as a rubbing portion are provided.
The jaw portion 69 is provided over the entire width direction so as to protrude slightly forward at the lower front end portion of the developing case 64, and as shown in FIG. 11, the developing roller is used to prevent toner leakage. It is arranged so as to oppose the peripheral surface of 67 from below.

The sled portion 70 is provided at both ends in the width direction sandwiching the jaw portion 69 at the lower front end portion of the developing case 64. As shown in FIG. 12 and FIG. It is formed in a curved L-shaped plate that protrudes from the front to the bottom.
Further, as shown in FIG. 9, a developing boss portion 71 as a pressed member that protrudes outward in the width direction is provided on the upper side of the rear end portion of both side walls of the developing housing 64. Further, a developing handle 72 for holding the developing cartridge 32 and operating the developing cartridge 32 with respect to the developing container 14 is provided on the rear wall of the developing case 64 at the center in the width direction. Further, on the bottom wall of the developing housing 64, contact protrusions 91 that protrude downward downward are formed at both rear ends.

  As shown in FIG. 1, the toner storage chamber 65 is formed as an upper portion (a rear portion in FIG. 8) of the developing housing 64 and stores toner as a developer for each color. That is, as toner in the toner storage chamber 65, for each process unit 27, yellow for the yellow process unit 27Y, magenta for the magenta process unit 27M, cyan for the cyan process unit 27C, and cyan for the black process unit 27K. A positively chargeable nonmagnetic one-component polymerized toner having a black color is accommodated.

  More specifically, as the toner for each color, a substantially spherical polymerized toner obtained by a polymerization method is used. The polymerization toner is a known polymerization such as 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. The main component is a binder resin obtained by copolymerization according to the method, and a toner base particle is formed by adding a colorant, a charge control agent, a wax, etc. to this, and further improves the fluidity. In order to achieve this, an external additive is added.

  As the colorant, the above-mentioned yellow, magenta, cyan and black colorants are blended. 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.

An agitator 73 for agitating the toner is rotatably supported on both side walls of the developing housing 64 at the lower side (front side in FIG. 8) in the toner storage chamber 65.
The supply roller 66 is rotatably supported on both side walls of the developing housing 64 on the lower front side (the front lower side in FIG. 8) of the toner storage chamber 65. The supply roller 66 has a metal roller shaft covered with a roller portion made of a conductive sponge member.

The developing roller 67 is disposed below the supply roller 66 (frontward in FIG. 8) so as to face the supply roller 66 and is compressed with the supply roller 66. As shown in FIG. 8, the developing roller 67 is arranged along the width direction so that the front surface is exposed at the front end portion of the developing housing 64, and the exposed lower end portion is as described above. In addition, the jaw part 69 is in pressure contact.
In the developing roller 67, a metal roller shaft 74 is covered with a roller portion 75 made of an elastic member such as a conductive rubber material. More specifically, the roller portion 75 is coated with an elastic roller portion made of conductive urethane rubber, silicone rubber, EPDM rubber, or the like containing carbon fine particles, and the surface of the roller portion. It is formed of a two-layer structure with a coat layer mainly composed of resin, polyimide resin or the like. The roller shaft 75 is rotatably supported on both side walls so that both end portions in the axial direction protrude outward in the width direction from both side walls of the developing housing 64.

  The layer thickness regulating blade 68 is provided over the entire width direction above the front end of the developing housing 64. As shown in FIG. 1, the layer thickness regulating blade 68 is formed by providing a semi-circular shaped pressing portion made of insulating silicone rubber at a free end portion of a blade made of a metal leaf spring member. The base end portion of the developing housing 64 is supported by the front end portion of the upper wall of the developing housing 64, and the pressing portion provided at the free end portion is disposed so as to press the rear surface of the developing roller 67.

  Further, in the main casing 2, each process accommodating portion 12 is formed with a guide groove 101 through which the drum shaft 60 of the drum cartridge 31 is inserted in order to guide the attachment / detachment of the drum cartridge 31, as shown in FIG. 14. ing. The guide groove 101 is provided in the left side plate 8 and the right side plate 9 so as to be opposed to each other so as to be recessed outward in the width direction, and along the attaching / detaching direction of the drum cartridge 31 so as to incline rearward from the upper side to the lower side. Has been placed.

  As shown in FIG. 19, each guide groove 101 is formed to be wide in the front-rear direction on the upper side, and an upstream guide portion 140 for guiding the passage of the drum cartridge 31 to the developing container 14, and the upstream guide portion 140. Is formed continuously from the lower side to the upper side, bent obliquely rearward with respect to the upstream side guide part 140, gradually narrowed toward the lower end part, and the holder part after the drum cartridge 31 has passed through the developing container part 14. 43 extends toward the expansion space 19 and includes a downstream guide portion 141 for guiding the mounting of the drum cartridge 31 to the drum accommodating portion 13.

A lower end portion (deepest portion) of the downstream guide portion 141 of each guide groove 101 is a receiving portion 102 that receives the drum shaft 60. The receiving portion 102 is formed in a concave shape in which the drum shaft 60 just fits in the front-rear direction, and is arranged so that the photosensitive drum 42 and a conveyance belt 80 described later come into contact when the drum shaft 60 abuts. .
In addition, a drum positioning groove 103 is formed in the middle of the upstream guide portion 140 in the longitudinal direction of each guide groove 101 as a first positioning portion that is recessed rearward in a rectangular shape in a side view. The drum positioning grooves 103 are formed at positions facing the left side plate 8 and the right side plate 9 in the width direction so that the drum boss portion 56 can be received.

  Further, as shown in FIG. 14, a boss insertion groove 133 into which the developing boss portion 71 of the developing cartridge 32 is inserted has the left side plate 8 and the right side plate 9 on the upper side of the upstream guide portion 140 of each guide groove 101. It is formed so as to cut out. As shown in FIG. 24, the boss insertion groove 133 is formed from the upper end portions of the left side plate 8 and the right side plate 9 in the direction in which the developing cartridge 32 is attached / detached, more specifically, when the developing cartridge 32 is attached / detached. Is formed so as to be cut straightly in a substantially U-shape obliquely downward and downward along a movement path that moves in the mounting direction and the detachment direction. The boss insertion groove 133 is formed deeper (downward) than the position where the developing boss 71 is disposed when the developing cartridge 32 is mounted on the drum cartridge 31. The width in the front-rear direction is formed such that the development boss 71 can be loosely fitted. Note that the upper end portion of the boss insertion groove 133 is formed in a substantially triangular shape that becomes wider upward so that the developing boss portion 71 can be easily received.

  The guide groove 101 includes a drum shaft locking mechanism 104 (see FIG. 22) for restricting the movement of the drum shaft 60 received by the receiving portion 20 and a restriction as a rotation restricting means for restricting the rotation of the drum cartridge 31. A spring 105 (see FIG. 19) and a contact / separation mechanism 106 (see FIG. 24) for bringing the developing cartridge 32 into and out of contact with the drum cartridge 31 are provided.

As shown in FIG. 22, the drum shaft locking mechanism 104 is provided in the vicinity of the receiving portion 102 on the outer surface of the left side plate 8 and the right side plate 9 of the drum accommodating portion 13, and includes a pressing cam 107 as a pressing member and an attached member. A bias spring 108 is provided.
The pressing cam 107 has a substantially rectangular plate shape, and the lower side of the rear end thereof is rotatably supported by a support shaft 109 provided so as to protrude outward in the width direction from the outer surface of the left side plate 8 and the right side plate 9. . This press cam 107 has a corner portion on the upper side of the rear end portion as a contact portion 110 that comes into contact with the drum shaft 60, and an upper end of the front end portion via an elliptical hole 111 drilled in the left side plate 8 and the right side plate 9. A contact shaft 112 that protrudes inward in the width direction is provided toward the attachment / detachment route of the drum cartridge 31 (the movement route of the drum shaft 60).

  The urging spring 108 is formed of a coil spring, the coil portion is wound around the support shaft 109, one end portion thereof is fixed to the left side plate 8 and the right side plate 9, and the other end portion is locked to the lower end portion of the pressing cam 107. Has been. Accordingly, the pressing cam 107 is always in a direction in which the contact portion 110 abuts the drum shaft 60 against the receiving portion 102 by the biasing force of the biasing spring 108, and the contact shaft 112 is in the drum cartridge 31. Is urged so as to rotate in a direction to advance into the attachment / detachment route (counterclockwise in FIG. 22).

  As shown in FIG. 19, the regulation springs 105 are provided in the vicinity of the drum positioning groove 113 on the outer surfaces of the left side plate 8 and the right side plate 9. The restriction spring 105 is a coil spring, and a coil portion is wound around a fixed shaft 115 provided so as to protrude outward in the width direction from the outer surfaces of the left side plate 8 and the right side plate 9, and one end portion of the restriction spring 105 is a left side plate. 8 and the right side plate 9 are fixed. The other end of the regulation spring 105 faces the drum positioning groove 113 and can be moved forward and backward with respect to the drum positioning groove 113 by an elastic force, and is always arranged to advance with respect to the drum positioning groove 113. Yes.

  Further, as shown in FIG. 24, the contact / separation mechanism 106 is provided in the vicinity of the boss insertion groove 133 on the outer surface of the left side plate 8 and the right side plate 9 and presses the developing boss portion 71 toward the mounting direction. A first pressing member 116, a first urging spring 117 that urges the first pressing member 116, a second pressing member 118 that presses the developing boss 71 in the detaching direction, and a second pressing member 118 are attached. A second urging spring 119 to be urged, and a cam 120 as a cam member facing the first pressing member 116 and the second pressing member 118 are provided.

  The first pressing member 116 has a substantially V shape in which one piece and the other piece are continuous via a bent portion. In the separated state, which will be described later, the one piece is disposed in parallel with the boss insertion groove 133. Are arranged along the front-rear direction. A boss contact portion 121 that contacts the developing boss portion 71 is formed at one end portion of the one piece so as to bend and extend forward from the one end portion in the separated state. The lower surface of the boss contact portion 121 is formed as an upper pressing surface 134 as a first pressing surface that presses the developing boss portion 71 from above. The upper pressing surface 134 has a pressing force that presses the developing boss portion 71 in the mounting direction at the time of contact with the developing boss portion 71, and the front end edge as a reference surface of the boss insertion groove 133. It is formed so as to be in contact with the developing boss portion 71 at an angle so that a pressing force pressing toward the developing portion is generated at the same time. A cam contact portion 122 that contacts the cam 120 is formed on the other end portion of the other piece as a protrusion protruding upward from the other end portion in the separated state.

  The first pressing member 116 has a support shaft 123 provided with a bent portion protruding outward in the width direction from the rear of the lower end portion (deepest portion) of the boss insertion groove 133 on the outer surface of the left side plate 8 and the right side plate 9. It is supported rotatably. As a result, the boss contact portion 121 can be moved forward and backward from the boss insertion groove 133, that is, the movement path of the development boss portion 71, and the cam contact portion 122 is formed in the boss insertion groove 133 with respect to the support shaft 123. On the opposite side, the cam 120 is provided so as to be freely separated from the lower side.

In such an arrangement, the support shaft 123 is arranged on the downstream side in the mounting direction of the developing boss portion 71 with respect to the boss contact portion 121 of the first pressing member 116.
The first urging spring 117 is a tension spring, and one end of the first urging spring 117 is provided so as to protrude from below the lower end portion (deepest portion) of the boss insertion groove 133 on the outer surface of the left side plate 8 and the right side plate 9. It is fixed to the fixed shaft 124. The other end is locked to the cam contact portion 122. As a result, the first pressing member 116 always moves the boss abutting portion 121 toward the moving path of the developing boss portion 71 by the urging force of the first urging spring 118 (forward) and the cam. The contact portion 122 is biased in a direction (upward) in the proximity of the cam 120.

  The second pressing member 118 has a substantially rectangular plate shape, and in the separated state, a boss contact claw portion 125 that protrudes obliquely forward upward and contacts the developing boss portion 71 is provided on the front side of the upper end portion. In the separated state, a rotation restricting claw portion 126 that protrudes obliquely forward and downward and is able to contact the first fixed shaft 124 is provided on the front side of the lower end portion. In the separated state, a cam contact protrusion 127 that protrudes upward and contacts the cam 120 is provided on the rear side of the upper end. In the separated state, a spring locking projection 128 that protrudes downward and locks the other end of the second biasing spring 118 is provided on the rear side of the lower end.

  The second pressing member 118 is supported by the support shaft 123 so as to be rotatable in the front-rear direction, so that the boss contact claw portion 125 is more developed than the boss contact portion 121 of the first pressing member 116. On the downstream side of the mounting direction of the portion 71, the boss insertion groove 133, that is, in the middle of the moving path of the developing boss portion 71, is movable in the mounting direction and the detaching direction of the developing boss portion 71 in the moving path. The claw portion 126 is detachable from the first fixed shaft 124, and the cam contact protrusion 127 is provided so as to be detachable from the cam 120 from the lower side on the opposite side of the boss insertion groove 133 with respect to the support shaft 123. It is done.

  The second urging spring 119 is formed of a tension spring, and one end of the second urging spring 119 is provided on the outer surface of the left side plate 8 and the right side plate 9 so as to protrude outward in the width direction from below the first fixed shaft 124. 129 is fixed. The other end is locked to the spring locking protrusion 128. Accordingly, the second pressing member 118 is always in the direction in which the boss contact claw portion 125 presses the developing boss portion 71 in the moving direction of the developing boss portion 71 by the urging force of the second urging spring 119. (Upward), the direction in which the rotation restricting claw portion 126 approaches the first fixed shaft 124 (upward), and the direction in which the cam contact protrusion 127 moves away from the cam 120 (downward) is urged.

Note that the spring constant of the second urging spring 119 is set to be smaller than the spring constant of the first urging spring 117.
Further, as shown in FIG. 28, both the first pressing member 116 and the second pressing member 118 are rotatably supported on the support shaft 123, but the first pressing member 116 is supported by the second pressing member 118. It is arrange | positioned with respect to the width direction outer side. Further, the boss contact portion 121 of the first pressing member 116 is formed so as to bulge inward in the width direction, and the boss contact claw portion 125 of the second pressing member 118 swells outward in the width direction. It is formed to come out. Therefore, the upper pressing surface 134 of the boss contact portion 121 and the lower pressing surface 135 of the boss contact claw portion 125 are arranged so as to overlap in the moving direction of the developing boss portion 71.

  As shown in FIG. 24, the cam 120 is formed in a substantially fan shape, and is provided on the left side plate 8 and the right side plate 9 so as to protrude outward in the width direction from the rear upper side of the support shaft 123 and is rotatably supported. It is connected to a camshaft 130 as a rotating shaft that cannot rotate relatively. The cam 120 has an abutting surface 131 as an arcuate second surface on the outer peripheral surface and a substantially V-shaped first that forms a central angle opposite to the abutting surface 131 with respect to the cam shaft 130. A separation surface 132 as a surface is continuously formed.

In the cam 120, the contact surface 131 and the separation surface 132 are selectively selected with respect to the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118 by the rotation of the cam shaft 130. Opposite to.
Although the developing cartridge 32 is mounted in the developing container 14, the contact surface 131 of the cam 120 is arranged so that the photosensitive drum 42 and the developing roller 67 are separated from each other during the non-image forming operation. Is in contact with the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118 and pushes them downward.

  As a result, the first urging spring 117 is pulled by the first pressing member 116 in the separated state, and the boss abutting portion 121 of the developing boss portion 71 resists the urging force of the first urging spring 117. It is rotated in a direction to retract with respect to the movement path. Further, in this separated state, the boss contact portion 121 is in a state of moving in the retracting direction, but slightly advances with respect to the moving path of the developing boss portion 71 within a range in which the developing cartridge 32 can be attached and detached. is doing.

  Further, in the second pressing member 118, the second urging spring 119 is compressed in the separated state, and the boss contact claw portion 125 becomes the developing boss portion with a pressing force larger than the urging force of the second urging spring 119. The rotation restricting claw portion 126 is rotated in the direction in which the 71 is pressed in the detaching direction and in the direction in which the rotation restricting claw portion 126 is close to the first fixed shaft 124. In this separated state, the boss contact claw portion 125 is arranged on the upstream side in the mounting direction of the development boss portion 71 with respect to the contact state described later in the movement path of the development boss portion 71.

  In the contact / separation mechanism 106, as shown in FIG. 32A, a cam shaft 130 is installed between the left side plate 8 and the right side plate 9 for each process accommodating portion 12, and the left side plate 8 and the right side plate 9 9, the cam 120 is connected to both ends of the cam shaft 130 as a pair. In addition, although not shown, the first pressing member 116 and the second pressing member 118 are provided as a pair corresponding to the pair of cams 120 for each process accommodating portion 12.

  In the left side plate 8, cam drive gears 136 are connected to the end portions of the cam shafts 130 protruding outside the left side plate 8 so as not to rotate relative to each other, and between the cam drive gears 136. An intermediate gear 137 that meshes with each adjacent cam drive gear 136 is provided. Thus, as shown in FIG. 32 (b), the driving force is input from the motor 138 via the pinion gear 109 to the gear train constituted by the cam driving gears 136 and the intermediate gears 137. A driving force is input to each camshaft 130 via the row, and each camshaft 130 is rotated, so that the pair of cams 120 are simultaneously rotated, and the cam contact portions of the pair of first pressing members 116 The contact surfaces 131 and the separation surfaces 132 of the pair of cams 120 are selectively opposed to the cam contact protrusions 127 of the pair 122 and the pair of second pressing members 118.

  In the color laser printer 1, in each process storage unit 12, first, the drum cartridge 31 for each color is mounted in the corresponding drum storage unit 13, so that each drum cartridge 31 is mounted in the main body casing 2. Then, each developing cartridge 32 is mounted on each drum cartridge 31 mounted on the main casing 2 by mounting the developing cartridge 32 for each color in the corresponding developing container 14.

The mounting of the drum cartridge 31 and the developing cartridge 32 to the main casing 2 will be described with reference to FIGS.
First, in order to attach the drum cartridge 31 to the drum accommodating portion 15 of the process accommodating portion 12, as shown in FIG. 15, the drum handle 57 is operated, and each drum boss portion 56 of the drum cartridge 31 is moved to each guide groove 101. The drum cartridge 31 is pushed downward. Then, each drum boss part 56 is first inserted into the upstream guide part 140 and guided so that the drum cartridge 31 passes through the developing container 14. Next, each drum boss portion 56 is inserted into the downstream side guide portion 141, and the holder portion 43 is guided toward the expansion space 19, and the drum cartridge 31 is attached to the drum housing portion 13. Thereby, smooth mounting of the drum cartridge 31 can be ensured.

  When the holder portion 43 of the drum cartridge 31 passes through the developing housing space 16 of the developing housing portion 14, the horn portions 51 of the drum cartridge 31 are moved to the rail portions of the developing housing portion 14 as shown in FIG. 20. Opposite to 17, they are frequently rubbed against each other during the mounting. If the horn portions 51 and the rail portions 17 are rubbed in this way, the horn portions 51 protrude from the holder upper wall 56 facing the scanner casing 35 toward the rail portions 17. In addition, since the rail portion 17 is formed in a thick strip shape, the front wall 34 of the scanner casing 35 and the holder upper wall 56 are brought into contact with each rail portion 17 by bringing the horn portions 51 into contact with each rail portion 17. A gap can be formed between them to prevent them from being rubbed against each other.

  Therefore, when the drum cartridge 31 is mounted, the horns 51 are rubbed against the rails 17 to prevent the holder upper wall 56 from sliding against the front wall 34 of the scanner casing 35. It is possible to prevent the drum cartridge 31 from being damaged during mounting. In particular, the horn portions 51 are rubbed against the rail portions 17 provided so as to face each other across the scanner casing 35 in the width direction, so that the holder portion 43 reliably rubs against the scanner casing 35. Can be prevented.

  Further, in the holder portion 43 of the drum cartridge 31, the scorotron charger 62 is behind the horn portion 51 in FIG. 2, that is, when the drum cartridge 31 is mounted, downstream of the horn portion 51 in the mounting direction of the drum cartridge 31. On the side, it is arranged in the holder part 43. As a result, when the drum cartridge 31 is mounted, the horn 51 is always positioned ahead of the scorotron charger 62, so that damage to the scorotron charger 62 can be reliably prevented.

  When the holder portion 43 of the drum cartridge 31 reaches the drum accommodating portion 13, the downstream guide portion 141 is bent obliquely rearward with respect to the upstream guide portion 140, as shown in FIG. When the drum shaft 60 guided by the downstream side guide portion 141 moves obliquely rearward and the drum shaft 60 hits the receiving portion 102, as shown in FIG. The extending portion 44 is arranged in an inclined shape facing backward and facing forward. In this state, the developing housing space 16 of the developing housing portion 14 is closed by the extending portion 44.

  Therefore, after the drum shaft 60 hits the receiving portion 102, the drum handle 57 is operated and the drum shaft 60 is supported by the receiving portion 102, and the extension portion 44 is rotated from the front to the rear. Then, as shown in FIG. 18, the extension portion 44 can be retracted from the developer accommodating space 16 to the extension portion accommodating space 18, and thus the developing cartridge 32 can be accommodated in the developer accommodating space 16. The accommodation space 16 can be opened.

  When the extended portion 44 is retracted from the developer accommodating space 16 to the extended portion accommodating space 18, each drum boss portion 56 faces each drum positioning groove 113 as shown in FIG. As shown in (b), each drum boss portion 56 is received in each drum positioning groove 103. Each drum boss portion 56 received in each drum positioning groove 103 abuts against the other end of each regulating spring 105 so as to slide, and as shown in FIG. Housed in the department.

On the other hand, the other end portion of each regulating spring 105 is pressed by each drum boss portion 56 to be temporarily retracted from each drum positioning groove 113 by its elastic force, and after each drum boss portion 56 has passed, by its elastic force. It advances again to each drum positioning groove 113.
Therefore, each drum boss portion 56 accommodated in the deepest portion of each drum positioning groove 113 is detached from each drum positioning groove 113 by the other end portion of each regulating spring 105 that re-enters each drum positioning groove 113. Is regulated. Thereby, the extension portion 44 can be restricted from being rotated from the rear to the front, and the extension portion 44 once retracted from the development storage space 16 to the extension portion storage space 18 Inadvertent advancement from the extended portion accommodating space 18 to the developer accommodating space 16 can be prevented, and positioning is ensured.

  When the drum cartridge 31 is detached, the other end of each regulating spring 105 is pressed by each drum boss portion 56 by operating the drum handle 57 and rotating the extending portion 44 from the rear to the front. As a result, the elastic force is temporarily retracted from each drum positioning groove 113, and after each drum boss portion 56 has passed, the elastic force is advanced again into each drum positioning groove 113. Accordingly, each drum boss portion 56 can be detached from each drum positioning groove 113.

  In the drum shaft locking mechanism 104, the drum shaft 60 contacts the receiving portion 102, and the drum housing 41 is arranged in an inclined shape with the holder portion 43 facing backward and the extending portion 44 facing forward. As shown in FIG. 22A, the lower end of each holder side wall 45 presses each abutment shaft 112, and each pressing cam 107 is pressed against each urging force of each urging spring 108. The contact shaft 112 is rotated in the direction of retracting from the attachment / detachment path of the drum cartridge 31 (clockwise in FIG. 22).

  Then, as described above, when the extending portion 44 is rotated from the front toward the rear, as shown in FIG. 22B, each pressing cam 107 is moved by the urging force of each urging spring 108. The contact shaft 112 is rotated in a direction (counterclockwise in FIG. 22) to advance into the attachment / detachment path of the drum cartridge 31, whereby the contact portion 110 is advanced so as to be closed with respect to the guide groove 101, The drum shaft 60 is pressed toward the receiving portion 102 to restrict the movement of the drum shaft 60 received by the receiving portion 102.

  When the drum cartridge 31 is detached, the lower end of each holder side wall 45 presses each contact shaft 112 by operating the drum handle 57 and rotating the extending portion 44 from the rear to the front. Each pressing cam 107 can be rotated in a direction (clockwise in FIG. 22) in which each contact shaft 112 retracts from the attachment / detachment path of the drum cartridge 31 against the urging force of each urging spring 108. . As a result, the abutting portion 110 is retracted so as to be open with respect to the guide groove 101, is separated from the drum shaft 60, and the restriction on the movement of the drum shaft 60 received by the receiving portion 102 is released.

In this way, in the drum cartridge 31, the holder portion 43 is accommodated in the drum accommodating space 15 including the enlarged space 19 of the drum accommodating portion 13, and the extending portion 44 is accommodated in the extending portion accommodating space 18 of the developing accommodating portion 14. By doing so, the main body casing 2 is mounted.
In the color laser printer 1, the front wall 34 of the scanner casing 35 is arranged so as to bulge from the partition plate 10 toward the front side, that is, toward the developer accommodating space 16 in each process accommodating portion 12. In the developing container 14, the passage of the drum cartridge 31 in the developing container 14 is restricted when the developing cartridge 32 is mounted on the drum cartridge 31. However, in the developing container 14, the drum cartridge 31 is allowed to pass through the developing container space 16 when the developing cartridge 32 is separated from the drum cartridge 31.

  For this reason, the front wall 34 of the scanner casing 35 bulges toward the developing housing space 16, so that the drum cartridge 31 and the developing cartridge 32 can be easily attached to the drum cartridge 31 even if a space obtained by simply adding and removing the attachment / detachment path is not secured. 31 is separated from the developing cartridge 32 and passes through the developing housing space 16 of the developing housing space 16 without interfering with the front wall 34 of the scanner casing 35, and is attached to the drum housing portion 13 to be attached to the drum housing space 15. Can be accommodated. Then, as will be described later, the drum cartridge 31 and the developing cartridge 32 can be mounted if the developing cartridge 32 is mounted in the developing storage section 14 and stored in the developing storage area 16.

  That is, in the color laser printer 1, the drum cartridge 31 separated from the developing cartridge 32 is used for the front wall 34 of the scanner casing 35 by using the developing housing space 16 of the developing housing portion 14 in which the developing cartridge 32 is housed. By passing through the drum housing 13, it is possible to reduce the space of the attachment / detachment path of the drum cartridge 31 and the developing cartridge 32 and to reduce the size of the apparatus. .

  In other words, in this color laser printer 1, even if the developing container 14 is formed to be narrower than the thickness of the drum cartridge 31 and the developing cartridge 32 in the state of being housed in the process container 12, only the drum cartridge 31 is first used. Is passed through the developing container 14 and mounted in the drum container 13, and then a developing cartridge 32 having a thickness smaller than the thickness of the holder 43 of the drum cartridge 31 is mounted in the developing container 14. The drum cartridge 31 and the developing cartridge 32 can be mounted. Therefore, it is possible to save the space for attaching and detaching the drum cartridge 31 and the developing cartridge 32, and it is possible to reduce the size of the apparatus.

  In other words, when the drum cartridge 31 and the developing cartridge 32 are mounted in the drum accommodating portion 13 and the developing accommodating portion 14 in the process accommodating portion 12, the holder portion 43 is disposed in the enlarged space 19 of the drum accommodating portion 13. However, in the state where the drum cartridge 13 is disposed in the enlarged space 19, the movement of the drum cartridge 31 in the attaching / detaching direction is restricted as described above, while the holder 43 is moved from the enlarged space 19 to the developing cartridge 32. If the drum cartridge 31 is shifted in the thickness direction by a distance corresponding to the thickness of the drum cartridge 31, movement of the drum cartridge 31 in the attachment / detachment direction is permitted. Therefore, after the drum cartridge 31 is first passed through the developing container 14 and then the holder 43 is disposed in the enlarged space 19, the drum cartridge 31 is mounted in the drum container 13, and the development in the developing container 14 is performed. The cartridge 32 can be mounted. Therefore, the drum cartridge 31 and the developing cartridge 32 can be mounted by mounting the developing cartridge 32 in the developing container 14 next. Therefore, it is possible to save the space for attaching and detaching the drum cartridge 31 and the developing cartridge 32, and it is possible to reduce the size of the apparatus.

Accordingly, the drum cartridge 31 is accommodated in the drum accommodating space 15 of the drum accommodating portion 13, and the developing cartridge 32 is accommodated in the developing accommodating space 16 of the developing accommodating portion 14. Reliable housing can be achieved.
In the color laser printer 1, when the drum cartridge 31 is mounted, the extending portion 44 is directed from the front to the rear with the drum shaft 60 supported by the receiving portion 102 and the drum shaft 60 as a rotation fulcrum. When the extending portion 44 is retreated from the developing housing space 16 to the extending portion housing space 18, the developing housing space 16 is opened so that the developing cartridge 32 can be housed. Therefore, the drum cartridge 31 can be mounted in the drum housing portion 13 so that the developing cartridge 32 can be housed in the developer housing space 16 of the developer housing portion 14 by a simple operation.

In addition, since the drum shaft 60 also serves as a pivot point, the positioning accuracy of the photosensitive drum 42 when the drum cartridge 31 is mounted can be improved, and the number of parts can be reduced.
Further, in a state where the drum cartridge 31 is mounted in the drum housing portion 13, the restriction spring 105 prevents the drum boss portion 56 from being detached from the drum positioning groove 113, and the extension portion 44 is rotated from the rear to the front. Movement is regulated. Therefore, it is possible to reliably hold the mounting of the drum cartridge 31 and prevent the mounting of the developing cartridge 32 from being hindered.

  Further, in the drum shaft locking mechanism 104, when the drum cartridge 31 is mounted (turned), the contact portion 110 of the pressing cam 107 that retreats from the attachment / detachment path of the drum cartridge 31 and opens the guide groove 101 is provided as a drum. When the shaft 60 is received by the receiving portion 102, the urging force of the urging spring 108 presses the drum shaft 60 toward the receiving portion 102 to restrict the movement of the drum shaft 60 received by the receiving portion 102. . Therefore, the drum cartridge 31 can be smoothly mounted on the drum housing portion 13 without receiving a large resistance from the contact portion 110. As a result, since the rigidity of the drum cartridge 31 does not need to be increased so much, the drum cartridge 31 can be downsized. In addition, since the contact portion 110 presses the drum shaft 60 toward the receiving portion 102 after the mounting, the mounting of the drum cartridge 31 and the reliable positioning of the photosensitive drum 42 can be achieved.

  Further, in the drum shaft locking mechanism 104, the pressing cam 107 is rotated against the urging force of the urging spring 108 by the lower end portion of the holder side wall 45 pressing the contact shaft 112. That is, the abutting portion 110 of the pressing cam 107 advances and retreats with respect to the guide groove 101, that is, the movement path of the drum shaft 60 in conjunction with the attachment and detachment of the drum cartridge 31 with respect to the drum housing portion 13. Therefore, reliable attachment / detachment of the drum cartridge 31 can be ensured.

Further, since the drum shaft lock mechanism 104 restricts the movement of the drum shaft 60 received by the receiving portion 102, the positioning accuracy of the photosensitive drum 42 can be improved, and the number of parts can be reduced. .
In the state where the holder portion 43 is housed in the drum housing space 15 of the drum housing portion 13, as shown in FIG. 21, each horn portion 51 gets over each rail portion 17 and is arranged below the scanner casing 35. Is done. As shown in FIG. 18, the upper portion of the scorotron charger 62 is also disposed below the scanner casing 35. Further, the photosensitive drum 42 comes into contact with a conveyance belt 80 described later.

  Further, in a state where the extending portion 44 is accommodated in the extending portion accommodating space 18 of the developer accommodating portion 14, as shown in FIG. 21, each extending side portion 52 is connected to the scanner casing 35 as shown in FIG. Is brought into contact with each rail portion 17 across the width direction. Thereby, it is possible to prevent the extension portion 44 from interfering with the scanner casing 35. In addition, since the reinforcing ribs 55 are formed on each extending side portion 52 and the strength of each extending side portion 52 is improved, deformation due to contact with each rail portion 17 can be prevented. . Further, as shown in FIG. 18, the extended rear wall 53 is disposed above the scanner casing 35. And since the drum handle 57 is provided in the extended rear wall 53, the grip of the drum handle 57 becomes easy and operability can be improved. Although not shown, the middle plate 54 is disposed to face the front wall 34 of the scanner casing 35 with the opening 58 of the middle plate 54 facing the emission window 40 of the scanner casing 35.

As described above, the drum cartridge 31 includes the holder portion 43 and the extension portion 44 as the drum housing 41, and can be increased in size. However, when the drum cartridge 31 is mounted, the extension portion 44 is extended. Since it can be accommodated in the outlet accommodating space 18, the apparatus can be miniaturized.
In the drum casing 41, the holder portion 43 and the extending portion 44 are integrally formed from a resin material to position the scorotron charger 62 and the photosensitive drum 42, and further, as will be described later, a development positioning groove 48. By receiving the roller shaft 74 of the developing roller 67, the developing cartridge 32 can be positioned with reference to the roller shaft 74. As a result, the drum casing 41 positions all of the scorotron charger 62, the photosensitive drum 42, and the developing cartridge 32. Therefore, the relative positioning accuracy of the drum casing 41 can be improved with a simple configuration. Further, since the developing cartridge 32 is positioned based on the roller shaft 74 of the developing roller 67, the positioning accuracy of the developing roller 67 with respect to the photosensitive drum 42 can be improved. Further, since the scorotron charger 62 is provided in the holder portion 43, the apparatus can be reduced in size while the scorotron charger 62 is disposed at an appropriate position.

  Next, in order to attach the developing cartridge 32 to the drum cartridge 31 attached to the main body casing 2 in the developing container 14, as shown in FIG. 24, each developing boss portion 71 of the developing cartridge 32 is inserted into each boss. As shown in FIG. 25, the developing cartridge 32 is pushed down so as to face the groove 133. Then, each developing boss portion 71 is inserted into each boss insertion groove 133 and comes into contact with the boss contact portion 121 of each first pressing member 116 that has slightly advanced with respect to the movement path of each developing boss portion 71. Then, after overcoming each boss contact portion 121, it comes into contact with each boss contact claw portion 125 facing the moving path of each development boss portion 71 as shown in FIG. 26. Each boss contact claw portion 125 is pressed toward the mounting direction by each developing boss portion 71, but the first contact member 116 is in contact with the contact surface 131 of the cam 120 because the cam contact portion 122 is in contact with the contact surface 131 of the cam 120. Is restricted. Therefore, each developing boss portion 71 is further restricted in the mounting direction and stops at the contact position with each boss contact claw portion 125. As a result, the developing cartridge 32 is in contact with the drum cartridge 31. The photosensitive drum 42 and the developing roller 67 are held in a separated state with a slight gap therebetween. Thus, the developing cartridge 32 is accommodated in the developing accommodating space 16 of the developing accommodating portion 14 and is attached to the drum cartridge 31 attached to the main casing 2.

In the laser printer 1, during the non-image forming operation, the developing cartridge 32 keeps such a separated state in which the photosensitive drum 42 and the developing roller 67 are separated from the drum cartridge 31, and during the image forming operation. The photosensitive drum 42 and the developing roller 67 are operated so as to be in contact with each other.
That is, in the laser printer 1, in order to change from the separated state to the contact state, first, in the separated state, the contact surface 131 of the cam 120 has the cam contact portion 122 of the first pressing member 116 and the second pressing member 118. The cam 120 is rotated from the state of being in contact with the cam contact protrusion 127, so that the separation surface 132 of the cam 120 causes the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118. Set it in a state of facing.

  In order to rotate each cam 120, as shown in FIG. 32, the motor 138 drives each cam shaft 130 via a pinion gear 139 and a gear train composed of each cam drive gear 136 and each intermediate gear 137. A force is input to rotate each camshaft 130. As a result, the pair of cams 120 are simultaneously rotated, and the pair of cams is opposed to the cam contact portion 122 of the pair of first pressing members 116 and the cam contact protrusion 127 of the pair of second pressing members 118. 120 spaced surfaces 132 face each other.

  When the separation surface 132 of the cam 120 faces the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118, as shown in FIG. The pressing force is released. Then, in the first pressing member 116, the first urging spring 117 is restored and contracted by itself, and the boss abutting portion 121 becomes the developing boss portion with the supporting shaft 123 as a fulcrum by the urging force of the first urging spring 117. It is rotated in the direction of further advancement with respect to the movement path 71. Further, the second pressing member 118 is stretched by the second urging spring 119 restored by itself, and the boss force in the movement path of the developing boss portion 71 with the support shaft 123 as a fulcrum by the urging force of the second urging spring 119. The contact claw portion 125 is rotated in the direction toward the downstream side in the mounting direction of the developing boss portion 71 with respect to the separated state.

  Then, by the rotation of the first pressing member 116, the upper pressing surface 134 of the boss contact portion 121 contacts the developing boss portion 71, and the developing boss portion 71 is connected to the mounting boss portion 71 and the boss insertion groove 133. Press toward the front edge of the. Further, the rotation of the second pressing member 118 moves the boss contact claw portion 125 to the downstream side in the mounting direction of the developing boss portion 71 with respect to the separated state. The side pressing surface 135 abuts on the developing boss portion 71 pressed by the upper pressing surface 134 of the boss abutting portion 121 and elastically receives the developing boss portion 71 by the urging force of the second urging spring 119. .

  Since the spring constant of the second urging spring 119 is set smaller than the spring constant of the first urging spring 117, the developing boss portion 71 is pushed from the upper pressing surface 134 of the boss abutting portion 121. The pressure is moved to the downstream side in the mounting direction with respect to the separated state, and is received by the lower pressing surface 135 of the boss contact claw portion 125 in that state. As the developing boss portion 71 moves downstream in the mounting direction, the developing roller 67 is brought into contact with the photosensitive drum 42, thereby bringing the photosensitive drum 42 into contact with the developing roller 67.

Further, in this contact state, the developing boss 71 is brought into contact with the front end edge of the boss insertion groove 133 by the pressing force from the upper pressing surface 134.
Further, in the contact state, the first pressing member 116 and the second pressing member 118 are biased by the first biasing spring 117 and the second biasing spring 119, respectively. A gap is formed between the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118.

  In order to change from the contact state to the separation state, first, in the contact state, the separation surface 132 of the cam 120 is spaced from the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118. In the same manner as described above, the cam 120 is rotated so that the contact surface 131 of the cam 120 contacts the cam contact portion 122 of the first pressing member 116 and the cam contact portion of the second pressing member 118. The state is brought into contact with the contact protrusion 127.

  When the contact surface 131 of the cam 120 faces the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118, as shown in FIG. Contacts the cam contact portion 122 of the first pressing member 116 and the cam contact protrusion 127 of the second pressing member 118, and pushes them downward. Then, in the first pressing member 116, the first urging spring 117 is pulled, and the boss abutting portion 121 has the developing boss portion with the support shaft 123 as a fulcrum against the urging force of the first urging spring 117. It is rotated in a retracting direction with respect to the movement path 71. Further, the second pressing member 118 is configured such that the second urging spring 119 is compressed, and the moving path of the developing boss portion 71 with the pressing force larger than the urging force of the second urging spring 119 with the support shaft 123 as a fulcrum. , The boss contact claw portion 125 is rotated in the direction toward the upstream side in the mounting direction of the developing boss portion 71 with respect to the contact state.

  Then, by the rotation of the first pressing member 116, the upper pressing surface 134 of the boss contact portion 121 is separated from the development boss portion 71, and the boss contact portion 121 slightly moves with respect to the movement path of the development boss portion 71. It will be in the state where it advanced. Further, by the rotation of the second pressing member 118, the boss contact claw portion 125 is moved to the upstream side in the mounting direction of the developing boss portion 71 with respect to the contact state, and accordingly, the boss contact claw portion 125 of the boss contact claw portion 125 is moved. The lower pressing surface 135 presses the developing boss 71 in the detaching direction. Then, the developing roller 67 is separated from the photosensitive drum 42 by the movement of the developing boss portion 71 toward the upstream side in the mounting direction, whereby the photosensitive drum 42 and the developing roller 67 are separated from each other. In this separated state, the boss contact portion 121 moves in the retracting direction with respect to the movement path of the developing boss portion 71 and slightly advances, so that the developing cartridge 32 is detached from the developing container 14. be able to.

  In the separation mechanism 106 of the color laser printer 1, as described above, the boss contact portion 121 of the first pressing member 116 moves in the retracting direction with respect to the movement path of the development boss portion 71 in the separation state. Therefore, the developing boss 71 can be moved in the moving path and the developing cartridge 32 can be attached and detached without the boss contact portion 121 interfering with the developing boss 71 in the moving path.

Further, in the contact state, the boss contact portion 121 of the first pressing member 116 moves in the advancing direction with respect to the movement path of the development boss portion 71. 71 can be reliably pressed toward the mounting direction.
As a result, the movement path of the developing boss portion 71 can be formed as an efficient substantially straight boss insertion groove 133 regardless of the boss contact portion 121. In addition, the boss contact portion 121 can reliably press the developing boss portion 71 in the mounting direction.

In addition, by forming the boss insertion groove 133 substantially straight, the apparatus can be reduced in size and the operability of attaching and detaching the developing cartridge 32 can be improved.
In the separated state, the boss contact portion 121 is in a state of moving in the retracting direction, but slightly advances with respect to the moving path of the developing boss portion 71 within a range in which the mounting and dismounting of the developing cartridge 32 is allowed. ing. Therefore, when the developing cartridge 32 is attached / detached, the boss contact portion 121 is elastically contacted with the developing boss portion 71 within a range that does not hinder the attaching / detaching of the developing boss portion 71. This contact can give the operator a clicking sensation when the developing cartridge 32 is attached / detached, so that the developing cartridge 32 can be prevented from being disposed at a halfway position in the attaching / detaching path.

  Even in the contact state where the boss contact portion 121 has moved in the retracting direction, if the developing handle 72 is operated and the developing cartridge 32 is pulled out of the developing accommodating portion 14 with a certain pulling force or more, the pressing force is reduced. Accordingly, the first biasing spring 117 moves in the retracting direction against the biasing force of the first biasing spring 117. Therefore, for example, even when an unexpected situation such as a power failure occurs, the developing cartridge 32 can be forcibly detached without damaging the first pressing member 116.

In the contact state, the upper pressing surface 134 of the boss contact portion 121 presses the developing boss portion 71 toward the mounting direction of the developing boss portion 71 and the front end edge of the boss insertion groove 133, The boss portion 71 is in contact with the front end edge of the boss insertion groove 133. Therefore, the developing cartridge 32 can be accurately positioned in the contact state.
Further, in the separation mechanism 106, in the separated state, the lower pressing surface 135 of the boss contact claw portion 125 of the second pressing member 118 reliably presses the developing boss portion 71 in the separation direction. During operation, the developing cartridge 32 can be retracted upstream in the mounting direction.

  Further, since the boss contact claw portion 125 of the second pressing member 118 contacts the development boss portion 71 in the middle of the mounting of the developing cartridge 32, the boss contact claw portion 125 even if the developing cartridge 32 is mounted vigorously. The momentum can be relieved by the boss abutment claw portion 125. Therefore, damage to the developing cartridge 32 and the drum cartridge 31 can be prevented.

  Further, the boss contact claw portion 125 is arranged on the downstream side in the mounting direction of the development boss portion 71 with respect to the boss contact portion 121 in the movement path of the development boss portion 71. Therefore, in the contact state, between the boss contact portion 121 and the boss contact claw portion 125, the developing boss portion 71 is pressed in the mounting direction by the boss contact portion 121, and at the same time, by the boss contact claw portion 125. The pressing force in the mounting direction of the developing cartridge 32 can be adjusted by pressing in the detaching direction. Therefore, an appropriate mounting state of the developing cartridge 32 can be ensured.

  In other words, in this contact / separation mechanism 106, in the contact state, the separation surface 132 of the cam 120, the cam contact portion 122, and the cam contact protrusion 127 are not in contact with each other. All of the above can be applied to the cam contact portion 122, and the pressing force in the mounting direction of the developing boss portion 71 can be adjusted by a preset spring constant of the first biasing spring 117. Further, all of the urging force of the second urging spring 119 can be applied to the boss contact claw portion 125, and the spring of the second urging spring 119 in which the pressing force in the mounting direction of the developing boss portion 71 is set in advance. It can be adjusted with a constant. The boss contact portion 121 reliably presses the developing cartridge 32 in the mounting direction with the urging force of the first urging spring 117 with the set pressing force, and the boss contact claw portion 125. However, the urging force of the second urging spring 119 surely presses the developing cartridge 32 in the direction of disengagement with the set pressing force.

  As a result, since the spring constant of the second urging spring 119 is set smaller than the spring constant of the first urging spring 117, the pressing force toward the mounting direction of the developing cartridge 32 is stabilized in the contact state. In the reduced state, the developing boss 71 can be held between the boss abutting portion 121 and the cam abutting protrusion 127, and an appropriate mounting state of the developing cartridge 32 can be ensured.

  That is, in the separation mechanism 106, the separation surface 132 of the cam member 120 faces the cam contact portion 122 and the cam contact protrusion 127 in a non-contact manner during the image forming operation. Then, the boss contact portion 121 moves in the advancing direction with respect to the attachment / detachment path by the urging force of the first urging spring 117, presses the developing boss portion 71, and the boss contact claw portion 125 The developing boss portion 71 pressed by the portion 121 is elastically received by being pressed toward the separation direction by the biasing force of the second biasing spring 119. Thus, the developing roller 67 and the photosensitive drum 42 can be brought into contact with each other with a stable pressing force by the biasing force of the first biasing spring 117 and the biasing force of the second biasing spring 119.

  In the non-image forming operation, the contact surface 131 of the cam member 120 faces the cam contact portion 122 and the cam contact protrusion 127 and presses them downward. Then, the boss contact portion 121 moves in the retracting direction with respect to the attachment / detachment path against the urging force of the first urging spring 117 and is separated from the developing boss portion 71, and the boss contact claw portion 125 is The developing boss portion 71 is pressed toward the separation direction with a pressing force larger than the urging force of the second urging spring 119. As a result, the developing cartridge 32 can be easily detached.

  Therefore, if the separation surface 132 and the contact surface 131 are selectively opposed to the cam contact portion 122 and the cam contact protrusion 127 by the rotation of the cam member 120, the boss contact portion 121 and the boss contact While the claw portion 125 can be appropriately advanced and retracted with respect to the moving path of the developing boss portion 71, the pressing force in the mounting direction of the developing boss portion 71 can be stably adjusted, and the developing cartridge 32 can be adjusted. Can be easily removed.

Further, as described above, when the developing roller 67 and the photosensitive drum 42 are brought into contact with each other during the image forming operation and the developing roller 67 and the photosensitive drum 42 are separated from each other during the non-image forming operation, the developing roller 67 and the photosensitive drum 42 are separated. Since the contact is made only when necessary, it is possible to prolong these lives.
In the separation mechanism 106, the first pressing member 116 and the second pressing member 118 are both rotatably supported by a common support shaft 123. Therefore, the configuration can be simplified and the number of parts can be reduced.

Further, since the support shaft 123 is disposed on the downstream side in the mounting direction of the developing boss portion 71 from the position where the boss contact portion 121 presses the developing boss portion 71 in the mounting direction, the first pressing member 116 is disposed. Can be reduced, and the apparatus can be downsized.
Further, the boss contact portion 121 of the first pressing member 116 is formed so as to bulge inward in the width direction, and the boss contact claw portion 125 of the second pressing member 118 swells outward in the width direction. The upper pressing surface 134 of the boss contact portion 121 and the lower pressing surface 135 of the boss contact claw portion 125 are arranged so as to overlap in the moving direction of the developing boss portion 71. For this reason, the pressing positions of the upper pressing surface 134 and the lower pressing surface 135 with respect to the developing boss portion 71 overlap in the moving direction of the developing boss portion 71, so that the developing boss portion is formed by the boss contacting portion 121 and the boss contacting claw portion 125. 71 can be pressed stably.

  In the contact / separation mechanism 106, when a driving force is input from the motor 138 to a gear train composed of the cam driving gears 136 and the intermediate gears 137, the pair of cams 120 are simultaneously rotated. Therefore, the plurality of pairs of cams 120 provided corresponding to the plurality of pairs of first pressing members 116 and the plurality of pairs of second pressing members 118 can be reliably rotated with a simple configuration. As a result, the attachment and detachment of the plurality of developing cartridges 32 can be reliably achieved by appropriate operations of the plurality of pairs of first pressing members 116 and the plurality of pairs of second pressing members 118.

  Further, in the developing cartridge 32 mounted in this way, the sled portion 70 of the developing housing 64 contacts the rear surface 33 of the partition plate 10 before the jaw portion 69 at the time of mounting, and remains as it is. The sled portion 70 is mounted while sliding on the rear surface 33 of the partition plate 10. Therefore, damage to the jaw portion 69 can be prevented, and toner leakage from the peripheral surface of the developing roller 67 can be reliably prevented.

  In the developing cartridge 32 attached to the drum cartridge 32, the roller shaft 74 of the developing roller 67 is positioned in the positioning groove of the drum casing 41 so that the developing container 14 can be selectively arranged in the separated state and the contact state. The developing cartridge 32 is positioned with respect to the drum cartridge 32 by being fitted into the valve 48. Further, the abutment protrusion 91 on the bottom wall of the developing housing 64 abuts on the rear surface 33 of the partition plate 10, whereby the developing cartridge 32 is positioned with respect to the developing container 14. That is, in this color laser printer 1, the drum housing 41 of the drum cartridge 31 is brought into contact with the deepest part of the drum positioning groove 113 and the drum boss part 56 is brought into contact with the drum positioning groove 113 from the drum positioning groove 113 of the drum boss part 56. The developing housing 64 of the developing cartridge 32 is positioned on the rear side by restricting the detachment of the developing cartridge 32, while the abutting projection 91 on the bottom wall of the developing housing 64 contacts the rear surface 33 of the partition plate 10, thereby Is positioned. As a result, the drum cartridge 31 and the developing cartridge 32 are positioned in the front-rear direction and in the opposite directions, respectively. Therefore, as compared with the case where the other is positioned with respect to either the drum cartridge 31 or the developing cartridge 32, Since it is difficult for tolerances to occur, the drum cartridge 31 and the developing cartridge 32 can be positioned accurately.

Further, in the laser printer 1, the drum cartridge 31 including the photosensitive drum 42 and the developing cartridge 32 including the toner storage chamber 65 can be detached from each other. Correspondingly, the drum cartridge 31 and the developing cartridge 32 can be individually replaced.
When the drum cartridge 31 is mounted in the drum accommodating portion 13, the photosensitive drum 42 is grounded by connection between contacts (not shown), and a charging bias is applied to the scorotron charger 62 during the image forming operation. Further, due to meshing of a gear (not shown), a driving force from the motor 138 is input during the image forming operation, and the photosensitive drum 42 is rotated.

  When the developing cartridge 32 is mounted in the developing container 14, a developing bias is applied to the roller shaft 74 of the developing roller 67 during the image forming operation due to connection between contacts (not shown). Further, due to the coupling of the coupling (not shown), the driving force from the motor 138 is input during the image forming operation, and the agitator 73, the supply roller 66, and the developing roller 67 are rotated.

  In each process unit 27, during the image forming operation, as shown in FIG. 1, in each developing cartridge 32, the toner for each color stored in the toner storage chamber 65 is stirred by the agitator 73. , Supplied to the supply roller 66. The toner supplied to the supply roller 66 is supplied to the development roller 67 by the rotation of the supply roller 66. At this time, the toner is positively frictionally charged between the supply roller 66 and the development roller 67 to which the development bias is applied. Is done.

The toner supplied to the developing roller 67 enters between the layer thickness regulating blade 68 and the developing roller 67 as the developing roller 67 rotates, and is carried on the surface of the developing roller 67 as a thin layer having a constant thickness. Is done.
On the other hand, in the drum cartridge 31, the scorotron charger 62 generates a corona discharge by applying a charging bias to uniformly positively charge the surface of the photosensitive drum 42. The surface of the photosensitive drum 42 is uniformly positively charged by the scorotron charger 62 as the photosensitive drum 42 rotates, and then exposed by high-speed scanning of the laser light from the scanner unit 30 to form on the paper 3. An electrostatic latent image corresponding to the image to be formed is formed.

  When the photosensitive drum 42 is further rotated, when the toner carried on the surface of the developing roller 67 and positively charged toner comes into contact with the photosensitive drum 42 by the rotation of the developing roller 67, the photosensitive drum 42. The electrostatic latent image formed on the surface, that is, the surface of the photosensitive drum 42 that is uniformly positively charged, 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 42 is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 42 for each color.

As shown in FIG. 1, the transfer unit 28 is disposed in the main body casing 2 above the paper feed unit 4 and below each process storage unit 12 along the front-rear direction, and includes a driving roller 78 and a driven roller. 79, a conveying belt 80 and a transfer roller 81 are provided.
The drive roller 78 is disposed in front of the process accommodating portion 12 in which the yellow process portion 16Y is accommodated. The driven roller 79 is disposed behind the process accommodating portion 12 in which the black process portion 16K is accommodated.

The conveyor belt 80 is an endless belt, and is formed of a resin such as conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed. The conveyor belt 80 is wound between a driving roller 78 and a driven roller 79.
The driven roller 79 is driven by the drive roller 78, and the image forming position where the conveyance belt 80 contacts the photosensitive drum 42 of each process unit 27 between the drive roller 78 and the driven roller 79. In FIG. 2, it is moved so as to rotate in the same direction as the photosensitive drum 42.

  Further, the transfer roller 81 is arranged so as to face the photosensitive drum 42 of each process unit 16 with the conveyance belt 80 interposed therebetween in the conveyance belt 80 wound between the driving roller 78 and the driven roller 79. Is provided. The transfer roller 81 has a metal roller shaft covered with a roller portion made of an elastic member such as a conductive rubber material. The transfer roller 81 is rotatably provided so as to rotate in the same direction as the circumferential movement direction of the conveyor belt 80 at an image forming position that faces and contacts the conveyor belt 80. At the time of transfer, a transfer bias is provided. Is applied.

  The sheet 3 fed from the sheet feeding unit 4 is conveyed from the front to the rear by the conveyor belt 80 that is moved around by the drive of the drive roller 78 and the driven roller 79. 27, the toner image for each color carried on the photosensitive drum 42 of each process unit 27 is sequentially transferred during the conveyance. As a result, a color image is formed on the paper 3.

  That is, for example, when a yellow toner image carried on the surface of the photosensitive drum 42 of the yellow process unit 27Y is transferred to the sheet 3, then the magenta toner carried on the surface of the photosensitive drum 42 of the magenta process unit 27M is transferred. The toner image is transferred onto the paper 3 on which the yellow toner image has already been transferred, and the cyan toner image carried on the surface of the photosensitive drum 42 of the cyan process unit 16C and the black process unit 16 are similarly operated. The black toner image carried on the surface of the photosensitive drum 42 is transferred in a superimposed manner, whereby a color image is formed on the paper 3.

  In the formation of such a color image, the color laser printer 1 has a tandem system configuration in which each process unit 27 includes a drum cartridge 31 and a developing cartridge 32 as a set, and a plurality of sets are provided for each color. Therefore, a toner image for each color can be formed at almost the same speed as that for forming a monochrome image, and a rapid color image can be formed. Therefore, it is possible to form a color image while reducing the size.

The fixing unit 29 is located behind the process storage unit 12 in the main casing 2 in which the black process unit 16K is stored, and faces the image forming position where the photosensitive drum 42 and the transfer belt 80 are in contact in the front-rear direction. Is arranged. The fixing unit 29 includes a heating roller 82 and a pressure roller 83.
The heating roller 82 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. Then, the surface of the heating roller 82 is heated to the fixing temperature by the halogen lamp. The pressure roller 83 is provided so as to press the heating roller 82.

The color image transferred onto the paper 3 is then conveyed to the fixing unit 29 and thermally fixed while the paper 3 passes between the heat roller 82 and the pressure roller 81.
The paper discharge unit 6 includes a paper discharge side U-shaped path 84, a paper discharge roller 85 as a discharge unit, and a paper discharge tray 86.
The discharge-side U-shaped path 84 has an upstream end adjacent to the fixing unit 29 at the lower side and a downstream end at the upper side so that the sheet 3 is fed rearward. Is formed as a substantially U-shaped paper 3 conveyance path so that the paper 3 is discharged forward.

The paper discharge roller 85 is provided as a pair of rollers at the downstream end of the paper discharge side U-shaped path 84.
The paper discharge tray 86 is formed on the upper surface of the main casing 2 as an inclined wall that is inclined downward from the front to the rear.
The sheet transported from the fixing unit 29 is fed rearward to the upstream end of the paper discharge side U-shaped path 84, and the transport direction is reversed in the paper feeding side U-shaped path 84. The paper is ejected forward onto a paper ejection tray 86 by a paper ejection roller 85.

  In the color laser printer 1, as described above, the pickup roller 22 in the paper feeding unit 4 picks up the paper 3 toward the front and the paper 3 toward the rear at each image forming position. The conveyance direction of the sheet 3 in the direction opposite to the conveyance direction and toward the rear at each image forming position, and the discharge direction of the sheet 3 toward the front of the discharge roller 85 in the discharge unit 6 Are arranged in the opposite direction. Therefore, it is possible to reduce the size of the apparatus while securing the conveyance path for the sheet 3.

  In this color laser printer 1, in each process storage unit 12, the drum cartridge 31 and the development cartridge 32 are arranged in the front-rear direction and the vertical direction (the thickness direction of the paper 3) with respect to the drum storage unit 13 and the development storage unit 14. It attaches and detaches along the direction which inclines with respect to it, ie, the direction which inclines back from the upper part to the lower part. Therefore, the operability of attaching / detaching the drum cartridge 31 and the developing cartridge 32 can be improved.

In the color laser printer 1, a plurality of sets of drum cartridges 31 and developing cartridges 32 and a plurality of corresponding scanner units 30 are alternately arranged in the front-rear direction. Therefore, the apparatus can be reduced in size by these efficient arrangements.
Further, in this color laser printer 1, in each process accommodating portion 12, the extending portion 44 of the drum casing 41 of the drum cartridge 31 is interposed between the scanner unit 30 and the developing cartridge 32. The middle plate 54 has an opening 58 through which laser light emitted from the scanner unit 30 toward the photosensitive drum 42 passes. For this reason, the extending portion 44 is interposed between the scanner unit 30 and the developing cartridge 32, and the photosensitive member is exposed from the scanner unit 30 by the opening 58 formed in the extending portion 44 while ensuring an efficient arrangement. Reliable passage of laser light emitted toward the drum 42 can be ensured.

  In the above description, in the drum shaft locking mechanism 104, as shown in FIG. 22, the pressing cam 107 is provided with the contact shaft 112, and the contact shaft 112 is brought into contact with the lower end portion of the holder side wall 45. Thus, the pressing cam 107 is rotated against the urging force of the urging spring 108, but as shown in FIG. 23, it is engaged with the roller shaft 74 of the developing roller 67 instead of the contact shaft 112. A fitting member 113 that can be detachably fitted can also be provided.

In FIG. 23, members similar to those in FIG. 22 are denoted by the same reference numerals, and description thereof is omitted.
In FIG. 23, the fitting member 113 has a substantially U-shaped plate shape, and when the developing roller 32 is attached to and detached from the drum cartridge 31 mounted in the drum accommodating portion 13 in the developing accommodating portion 14, the developing roller 67. The rotating shaft 114 is provided so as to protrude outward in the width direction from the outer surface of the left side plate 8 and the right side plate 9 so that the roller shaft 74 can be engaged and disengaged and rotated forward and backward according to the attachment / detachment movement of the roller shaft 74 , Is supported rotatably.

  Further, the upper end of the front side of the pressing cam 107 abuts on the fitting member 113, and the abutting portion 110 always abuts against the receiving portion 102 by the urging force of the urging spring 108. In addition, the fitting member 113 is advanced in the attaching / detaching path of the developing cartridge 32 (attaching / detaching path of the roller shaft 74) so as to be engaged with the roller shaft 74 (counterclockwise in FIG. 23). , Biased to rotate.

When the developing cartridge 32 is detached, the fitting member 113 is biased by the biasing spring 108 by the separation of the roller shaft 74 of the developing roller 67 before that, as shown in FIG. Against this, it is rotated so as to retract from the attachment / detachment path of the roller shaft 74, and is held in the retracted state.
When the developing cartridge 32 is mounted, as shown in FIG. 23B, the roller shaft 74 is fitted to each fitting member 113, and the fitting member 113 is advanced into the attaching / detaching path of the developing cartridge 32. Rotate in the direction of rotation (counterclockwise in FIG. 23). Then, the pressing cam 107 is rotated by the urging force of each urging spring 108, and the abutting portion 110 advances so as to be closed with respect to the guide groove 101, and the drum shaft 60 is directed toward the receiving portion 102. The movement of the drum shaft 60 received by the receiving portion 102 is restricted by pressing.

As described above, in the drum shaft locking mechanism 104 shown in FIG. 23, the abutting portion 110 of the pressing cam 107 is interlocked with the attachment / detachment of the developing cartridge 32 with respect to the developing accommodating portion 14, so Move forward and backward with respect to the travel path. Therefore, reliable attachment / detachment of the drum cartridge 31 can be ensured.
In the above description, in the contact / separation mechanism 106, the second urging spring 119 is provided on the second pressing member 118. For example, as shown in FIG. 33, the center of gravity of the second pressing member 118 is always The second pressing member 118 is not provided with the second urging spring 119 as long as it is rotatably supported by the support shaft 123 so that the rotation restricting claw 126 is lowered and the cam contact protrusion 127 is raised. May be.

  In the above description, the tandem-type color laser printer 1 that directly transfers from the photosensitive drums 42 to the paper 3 has been exemplified. However, the present invention is not limited to this, and for example, toner for each color. An image can be configured as an intermediate transfer type color laser printer in which an image is temporarily transferred from each photosensitive member to an intermediate transfer member and then transferred to a sheet at once, and further, can be configured as a monochrome laser printer.

1 is a cross-sectional side view of a main part showing an embodiment of a color laser printer as an image forming apparatus of the present invention. It is the perspective view which looked at the drum cartridge of the color laser printer shown in FIG. 1 from the front upper side. It is the perspective view which looked at the drum cartridge of the color laser printer shown in FIG. 1 from the rear lower side. It is a top view of the drum cartridge of the color laser printer shown in FIG. It is a front view of the drum cartridge of the color laser printer shown in FIG. It is a right view of the drum cartridge of the color laser printer shown in FIG. It is a left view of the drum cartridge of the color laser printer shown in FIG. It is the perspective view seen from the front upper side of the developing cartridge of the color laser printer shown in FIG. FIG. 2 is a perspective view of the color laser printer shown in FIG. 1 as viewed from the rear rear side of the developing cartridge. FIG. 2 is a plan view of a developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a front view of a developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a right side view of the developing cartridge of the color laser printer shown in FIG. 1. FIG. 2 is a left side view of the developing cartridge of the color laser printer shown in FIG. 1. It is the perspective view seen from the front upper side of the main body casing of the color laser printer shown in FIG. FIG. 6 is a side view illustrating a mounting state of the drum cartridge with respect to the process storage unit (a state in the middle of passage of the development storage unit). It is a side view explaining the mounting state (drum accommodating part arrival state) with respect to the process accommodating part of a drum cartridge. It is a side view explaining the mounting state (in the middle of rotation) with respect to the process accommodating part of a drum cartridge. It is a side view explaining the mounting state (mounting completion state) with respect to the process accommodating part of a drum cartridge. FIG. 4 is a side view for explaining a locked state of a restriction spring with respect to a drum boss portion in a mounted state of a drum cartridge with respect to a process accommodating portion, where (a) is a state before engagement, (b) is a state during engagement, c) shows an engagement completion state. FIG. 6 is a front cross-sectional view illustrating a mounting state of the drum cartridge with respect to a process storage unit (a state in the middle of passage of the development storage unit). It is a front sectional view explaining the mounting state (mounting completion state) with respect to the process accommodating part of a drum cartridge. FIG. 7 is a side view for explaining a locking state of a pressing cam (a mode interlocked with the attachment / detachment of the drum cartridge) with respect to the drum shaft in a mounting state of the drum cartridge with respect to the process housing portion, wherein (a) is a state before engagement; b) shows an engagement completion state. FIG. 4 is a side view for explaining a locking state of a pressing cam (a mode interlocked with the attachment and detachment of the developing cartridge) with respect to the drum shaft in a mounting state of the drum cartridge with respect to the process accommodating portion, (a) is a state before engagement; b) shows an engagement completion state. FIG. 10 is a side view illustrating a mounting state of the developing cartridge with respect to the process accommodating portion (a state before insertion of the developing boss portion into the boss insertion groove). FIG. 10 is a side view illustrating a mounting state of the developing cartridge with respect to the process accommodating portion (a state where the developing boss portion is in contact with the boss contact portion). FIG. 10 is a side view illustrating a mounted state (separated state) of the developing cartridge with respect to the process storage unit. FIG. 6 is a side view illustrating a mounting state (contact state) of the developing cartridge with respect to a process storage unit. FIG. 6 is a plan view for explaining a mounted state (separated state) of a developing cartridge with respect to a process accommodating portion. FIG. 7 is a front view illustrating a mounted state (separated state) of the developing cartridge with respect to a process storage unit. FIG. 6 is a plan view illustrating a mounting state (contact state) of the developing cartridge with respect to a process storage unit. FIG. 7 is a front view illustrating a mounting state (contact state) of the developing cartridge with respect to a process storage unit. It is a principal part block diagram of the drive path | route of a cam, Comprising: (a) is a top view, (b) is a side view. It is other embodiment (a mode without the 2nd energizing spring) of the 2nd press member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color laser printer 12 Process accommodating part 31 Drum cartridge 32 Developing cartridge 41 Drum housing 42 Photosensitive drum 43 Holder part 44 Extension part 51 Tsuno part 52 Extension side part 53 Extension rear wall 55 Reinforcement rib 57 Drum handle 58 Opening part 62 Scorotron charger 64 Development housing 67 Development roller 69 Jaw part 70 Sled part

Claims (13)

In a photosensitive cartridge comprising a first housing, a photoconductor and a charger provided in the first housing, and detachably mounted in a cartridge housing portion of the image forming apparatus.
The first housing integrally includes a main body portion that accommodates the charger and the photosensitive member, and an extending portion that is disposed on the downstream side in the mounting direction with respect to the main body portion. A photosensitive cartridge.   2. The photosensitive cartridge according to claim 1, wherein the main body is formed to be thicker than the extension in a thickness direction orthogonal to a mounting direction of the photosensitive cartridge.   The first housing is provided with a protrusion protruding outward so as to prevent sliding of the first housing with respect to the cartridge housing portion when the photosensitive cartridge is attached to or detached from the cartridge housing portion. The photosensitive cartridge according to claim 1, wherein the photosensitive cartridge is provided.   4. The photosensitive cartridge according to claim 3, wherein the protrusion is provided on the main body of the first housing on the downstream side of the charger in the mounting direction of the photosensitive cartridge. 5. The extending portion of the first housing includes an extending side portion extending so as to face each other with a gap along the mounting direction of the photosensitive cartridge.
5. The extension part according to claim 1, wherein a reinforcement part for reinforcing each extension side part is provided in each extension side part along the mounting direction of the photosensitive cartridge. A photosensitive cartridge according to claim 1.   The grip portion for operating the attachment / detachment of the photosensitive cartridge with respect to the cartridge housing portion is provided in the extension portion of the first casing. The photosensitive cartridge as described. The first housing includes an extending end portion that connects upstream ends of the extending side portions in the mounting direction of the photosensitive cartridge,
The photosensitive cartridge according to claim 6, wherein the grip portion is provided at the extended end portion. The first housing can be mounted with a developing cartridge including a developing roller,
The photosensitive cartridge according to claim 1, wherein the first housing positions the charger, the photosensitive member, and the developing cartridge.   The photosensitive cartridge according to claim 8, wherein the first casing positions the developing cartridge with reference to an axis of the developing roller.   The first casing is formed with an opening for passing laser light toward the photoconductor in a portion surrounded by the main body, each extending side, and the extending end. The photosensitive cartridge according to claim 5, wherein the photosensitive cartridge is characterized. A photosensitive cartridge according to any one of claims 1 to 10,
A second housing, and the developing roller disposed in the second housing, a part of which is exposed from the second housing, and is detachable from a cartridge housing portion of the image forming apparatus. A process cartridge comprising: a developing cartridge to be mounted. A second housing, and the developing roller disposed in the second housing, a part of which is exposed from the second housing, and is detachable from a cartridge housing portion of the image forming apparatus. In the mounted developing cartridge,
In order to prevent leakage of the developer, provided in the second casing and disposed opposite the circumferential surface of the developing roller along the longitudinal direction of the developing roller from the opposite direction of the bulging portion. A pressure-contact portion pressed against the peripheral surface;
A developing cartridge, comprising: a sliding portion provided so as to come into contact with the cartridge housing portion prior to the press contact portion when the developing cartridge is mounted, and sliding with the cartridge housing portion. . A photosensitive cartridge including a first housing, a photoconductor and a charger provided in the first housing, and detachably mounted in a cartridge housing portion of the image forming apparatus;
A process cartridge comprising the developing cartridge according to claim 12.

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