JP4297071B2 - Developing cartridge, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image with a developer. The present invention also relates to a process cartridge and a developing cartridge that can be easily attached to and detached from the above-described image forming apparatus and used for an image forming process in the image forming apparatus.

As the developing cartridge, one described in Patent Document 1 below is known. In this developing cartridge, a developing roller is rotatably disposed in an opening of a case that accommodates the developer. Safeguard members that suppress the leakage of the developer are provided at both ends in the longitudinal direction of the opening. According to this configuration, even if the developer leaks out to the outside at the both end portions of the opening, the developer can be blocked by the safeguard member.
Japanese Patent Laid-Open No. 2001-60040

  However, even with the above configuration, when the user replaces the developing cartridge, the developer blocked by the safeguard member in the used developing cartridge gets over the safeguard member and the There is a possibility of leakage outside and diffusion outside the image forming apparatus (for example, in a collection box of a used developing cartridge).

Means for Solving the Problems and Effects of the Invention

  SUMMARY An advantage of some aspects of the invention is to provide a developing cartridge, a process cartridge, and an image forming apparatus in which the diffusion of the developer can be suppressed.

  A developing cartridge that is a subject of the present invention includes a developing roller and a developing unit case, and is configured to be detachable from the image forming apparatus (in this case, “removable from the image forming apparatus” "Includes a case where the developing cartridge is detachable with respect to another cartridge (for example, a process cartridge) that is detachable with respect to the image forming apparatus. It is configured to be detachable from the image forming apparatus via a cartridge). The developing roller is configured to carry a developer for developing the electrostatic latent image formed on the image carrier on the peripheral surface. The developing unit case is formed with an opening that exposes the peripheral surface of the developing roller to the outside. The developing unit case is configured to accommodate the developing roller while rotatably supporting the developing roller.

  A process cartridge that is an object of the present invention includes the image carrier on which an electrostatic latent image is formed, a process case that accommodates the image carrier, and the developer cartridge that is detachable from the process case. I have.

  An image forming apparatus that is an object of the present invention includes the image carrier on which an electrostatic latent image is formed, and the developing cartridge that is detachably mounted opposite to the image carrier (note that As used herein, “the detachably mounted developer cartridge” is detachable from the image forming apparatus via the other cartridge (for example, a process cartridge containing the image carrier). Including the case where it can be worn.) The developing cartridge includes the developing roller and the developing unit case. The developing roller is disposed to face the image carrier and is configured to carry a developer for developing the electrostatic latent image on a peripheral surface.

(1) In order to achieve the above object, a feature of the present invention is that a movable cover and an accommodating portion are provided. The movable cover has a first position facing the peripheral surface so as to cover the peripheral surface of the developing roller exposed from the opening, and a second position (excluding the peripheral surface) exposing the peripheral surface to the outside. The developing unit case is supported so as to be movable between the lower surface and the lower surface. The accommodating portion is provided on the movable cover so as to accommodate the developer leaked from the gap between the opening and the developing roller at the second position.

  According to this configuration, when the developing cartridge is detached from the image forming apparatus, the position of the movable cover provided in the developing cartridge is set to the first position. Thereby, the movable cover faces the peripheral surface so as to cover the peripheral surface of the developing roller exposed from the opening of the developing unit case. Therefore, the peripheral surface of the developing roller can be protected when the developing cartridge is detached from the image forming apparatus.

  Further, when the developing cartridge is attached to the image forming apparatus, the position of the movable cover is set to the second position. Accordingly, the accommodating portion formed in the movable cover is positioned below the peripheral surface of the developing roller exposed from the opening of the developing unit case. Therefore, the storage unit can store the developer leaked from the gap between the opening and the developing roller during the image forming operation at the second position.

(2) Here, for example, the accommodating portion in the configuration (1) may be provided corresponding to at least both end portions of the developing roller.

  According to this configuration, during the image forming operation, the developer leaked from the gap between the both end portions of the developing roller and the opening can be stored in the storage portion.

(3) Further, for example, the storage portion in the configurations (1) to (2) may be provided at least corresponding to a central portion in the rotation central axis direction of the developing roller.

  According to this configuration, during the image forming operation, the developer leaked from the gap between the central portion of the developing roller and the opening can be accommodated by the accommodating portion.

(4) Further, for example, the accommodating portion in the configurations (1) to (3) may be formed with a width wider than a width in the rotation central axis direction of the developing roller.

  According to this configuration, during the image forming operation, the developer leaking from the gap between the opening and the developing roller can be accommodated in the region wider than the width of the developing roller by the accommodating portion.

(5) Further, for example, the movable cover in the configurations (1) to (4) may be supported so as to be rotatable about the rotation center axis of the developing roller. According to such a configuration, the above-described configurations can be realized with a simple structure.

(6) Further, for example, a cross-sectional shape of the housing portion in the configurations (1) to (5) by a surface orthogonal to the rotation center axis of the developing roller is configured in a box shape having an opening, The opening may be formed so as to allow the developer falling from above to pass through and be accommodated in the box at the second position.

  According to such a configuration, during the image forming operation, the developer leaked from the gap between the opening of the developing unit case and the developing roller passes through the opening in the storage and is stored in the box. . Thereafter, when the developing cartridge is detached from the image forming apparatus, the position of the movable cover is set to the first position facing the peripheral surface so as to cover the peripheral surface of the developing roller. At this time, the developer accommodated in the accommodating portion can be held in the box so as not to leak outside.

(7) Moreover, the said accommodating part in the said structure (6) may be comprised from the 1st outer plate, the 2nd outer plate, and the inner plate, for example. The first outer plate constitutes a bottom plate of the housing portion at the second position, and is configured to face the developing roller at the first position. The second outer plate forms a bottom plate of the housing portion at the first position, and extends upward from an end portion of the first outer plate at the second position. Connected and provided. The inner plate is provided to extend upward from an end portion of the second outer plate at the first position, and does not face the peripheral surface of the exposed developing roller at the second position. In the position.

  According to such a configuration, during the image forming operation, the position of the movable cover is set to the second position, so that the housing portion formed in the movable cover can move the opening of the developing unit case. It is located below the peripheral surface of the developing roller exposed from the portion. At this time, the first outer plate constitutes a bottom plate in the housing portion. Further, the inner plate is in a position not facing the peripheral surface of the developing roller (that is, a position where the developer is not blocked from dropping on the first outer plate). Therefore, during the image forming operation, the developer leaked from the gap between the opening of the developing unit case and the developing roller is not blocked by the inner plate and is set in the second position. Passing through the opening in the storage unit, deposits on the first outer plate constituting the bottom plate in the housing portion.

  Thereafter, when the developing cartridge is detached from the image forming apparatus, the positions of the movable cover and the accommodating portion are set to the first position facing the peripheral surface so as to cover the peripheral surface of the developing roller. Is set. At this time, the first outer plate faces the developing roller. Further, the second outer plate constitutes a bottom plate of the housing portion. Further, the inner plate is provided so as to extend upward from an end portion of the second outer plate. Therefore, the developer accommodated in the accommodating portion can be accommodated in the box including the first outer plate, the second outer plate, and the inner plate.

(8) Further, for example, in addition to the configurations of (1) to (7), a first holding mechanism that holds the movable cover at the first position, and the second position at the first holding mechanism. And a second holding mechanism that holds the movable cover.

  According to this configuration, when the developing cartridge is detached from the image forming apparatus, the position of the movable cover provided in the developing cartridge is set to the first position. Then, the movable cover is held at the first position by the first holding mechanism. Accordingly, when the developing cartridge is detached from the image forming apparatus, the peripheral surface of the developing roller can be reliably protected by the movable cover.

  Further, when the developing cartridge is attached to the image forming apparatus, the position of the movable cover is set to the second position. The movable cover is held at the second position by the second holding mechanism. Accordingly, during the image forming operation, the developer leaked from the gap between the opening and the developing roller can be accommodated by the accommodating portion at the second position.

(9) Further, for example, the movable cover in the configuration (8) is configured to face the conveyance path of the recording medium at the second position, and the movable cover at the second position. A rib that guides the conveyance of the recording medium may be erected at a portion facing the conveyance path.

  According to this configuration, the position of the movable cover is set to the second position during the image forming operation. At this time, the guide rib protrudes from the portion of the movable cover facing the transport path toward the transport path. The guide rib guides the conveyance of the recording medium during the image forming operation.

(10) Further, for example, in addition to the configurations of (1) to (9), a moving mechanism for moving the movable cover from the second position toward the first position may be provided. Good. As this moving mechanism, for example, a configuration using elasticity of metal or synthetic resin (coil springs stretched between the movable cover and the developing unit case, or a helical spring arranged around the rotation center of the movable cover. Springs and the like) can be suitably used.

  According to this configuration, when the developing cartridge is detached from the image forming apparatus, the movable cover provided on the developing cartridge is moved from the second position to the first position by the moving mechanism. Is done.

(11) Further, for example, in addition to the configuration of (10), a damper mechanism that further attenuates acceleration when the movable cover moves from the second position to the first position may be provided. Good. As this damper mechanism, for example, a configuration using the viscosity or pressure of a gel-like substance (grease filled in a contact portion between the movable cover and the developing unit case, or spanned between the movable cover and the developing unit case). An oil damper mechanism or the like can be preferably used.

  According to this configuration, when the movable cover provided in the developing cartridge is moved from the second position to the first position by the moving mechanism, the acceleration of the movable cover is attenuated by the damper mechanism. Is done. Thereby, when the movable cover moves, the developer accommodated in the movable cover is suppressed from being scattered outside.

  Hereinafter, embodiments of the present invention (embodiments that the applicant considers best at the time of filing of the present application) will be described with reference to the drawings.

<Overall configuration of laser printer>
FIG. 1 is a side sectional view of a laser printer 100 which is an embodiment of an image forming apparatus of the present invention.

  The laser printer 100 includes a main body 110 and a feeder unit 120 for supplying a recording medium (paper) to the main body 110. A process cartridge 130 for forming an image of a developer (toner) on a sheet is detachably mounted in the main body 110. A scanner unit 140 that irradiates a photosensitive drum 133 provided in the process cartridge 130 with laser light is disposed in the main body 110. Further, in the main body 110, a paper feeding unit 150 for supplying paper toward the process cartridge 130, and a fixing unit for fixing an image formed by toner formed on the paper by the process cartridge 130 on the paper. 160 and a paper discharge unit 170 that discharges the paper that has passed through the fixing unit 160 to the outside of the laser printer 100.

<Description of “paper transport direction”, “paper width direction”, “front”, “back”>
The laser printer 100 is configured so that the paper is transported along a paper transport path PP (paper path: two-dot chain line). Therefore, in the following description, a direction from the feeder unit 120 toward the paper discharge unit 170 along the paper transport path PP in FIG. 1 is referred to as a “paper transport direction”.

  The right end of the laser printer 100 in the drawing is referred to as the “front surface” of the laser printer 100, and the left end of the laser printer 100 in the drawing is referred to as the “rear face” of the laser printer 100.

  Further, a direction perpendicular to the paper conveyance direction and the vertical direction (the height direction of the laser printer 100) in FIG. 1 (that is, the normal direction of the paper surface of FIG. 1: the width direction of the laser printer 100) is referred to as “paper width direction”. Called.

<Configuration of casing of main body>
The outer cover 111 is a substantially rectangular parallelepiped member that constitutes the casing of the main body 110, and is integrally formed of a synthetic resin plate. The outer cover 111 is provided so as to cover a main frame (not shown) for supporting various members accommodated in the main body 110. A paper discharge tray 111 b is formed on the upper surface 111 a of the outer cover 111. The paper discharge tray 111b is composed of a slope formed so as to extend obliquely downward from the front side to the back side of the upper surface 111a. That is, the paper discharge tray 111b is composed of a recess formed in the upper surface 111a. A paper discharge port 111c having an opening is formed above the outer cover 111 and above the lower end of the paper discharge tray 111b. The paper discharge tray 111b is configured to receive the paper discharged from the paper discharge port 111c.

  An opening is formed on the front surface side of the outer cover 111, and a plate-like front cover 112 is mounted so as to close the opening. A hole 112 a constituting the rotation center of the front cover 112 is formed at the lower end of the front cover 112. A pair of pins (not shown) are erected along the paper width direction at the opening of the outer cover 111. By inserting this pin into the hole 112a of the outer cover 111, the front cover 112 is supported so as to be openable and closable along the paper transport direction with the pin as a center.

<Configuration of feeder unit>
A feeder case 121 constituting the casing of the feeder unit 120 is configured to accommodate a large number of sheet-like sheets in a stacked state. In the feeder case 121, a paper pressing plate 123 and a separation pad 125 are arranged.

  The paper pressing plate 123 is supported so as to be swingable around an end portion on the back side (the far side from the separation pad 125 in FIG. 1). An end of the sheet pressing plate 123 on the front side (closer to the separation pad 125 in FIG. 1) is biased upward by a spring (not shown). The separation pad 125 is disposed in the vicinity of the front end portion of the feeder case 121 and on the downstream side of the paper pressing plate 123 in the paper transport direction, and is biased upward from below by a spring (not shown). . The upper surface of the separation pad 125 is made of a material having a higher friction coefficient than paper, such as rubber.

<Schematic configuration of process cartridge>
FIG. 2 is a diagram showing a state when the process cartridge 130 is attached / detached. As shown in FIG. 2, the laser printer 100 according to the present embodiment has the process cartridge 130 mounted from the front side of the laser printer 100 by opening the front cover 112 to the front side (right side in the figure). It is configured to be detachable.

  Referring again to FIG. 1, a developing cartridge 132 is detachably attached to a process case 131 that forms a casing of the process cartridge 130. That is, the developing cartridge 132 is detachably attached to the main body 110 of the laser printer 100 via the process case 131.

  In the process case 131, a photosensitive drum 133 on which an electrostatic latent image is formed is accommodated. The photosensitive drum 133 is supported by the process case 131 so that it can be rotated around the rotation shaft 133b in the direction of the arrow in the drawing in synchronism with the conveyance of the paper during image formation. Above the photosensitive drum 133, a charger 134 for uniformly charging the circumferential surface of the photosensitive drum 133 is disposed. The charger 134 is supported by a process case 131. A slit 131 t is formed in the upper part of the process case 131. By irradiating the photosensitive drum 133 with laser light modulated in accordance with image information through the slit 131t, an electrostatic latent image can be formed on the peripheral surface of the photosensitive drum 133.

  In the process case 131, a transfer roller 135 for transferring the toner carried on the peripheral surface of the photosensitive drum 133 onto a sheet is accommodated. The transfer roller 135 is disposed below the photosensitive drum 133 and at the bottom of the process cartridge 130 so that the upper portion of the peripheral surface thereof faces the photosensitive drum 133. The transfer roller 135 is supported by the process case 131 so as to be rotatable about the rotation shaft 135b, and rotates in the direction of the arrow in the drawing in synchronization with the rotation of the photosensitive drum 133 in the direction of the arrow in the drawing. ing. The bottom of the transfer roller 135 is covered with a transfer roller cover 131 a that constitutes a part of the process case 131. The inner surface of the transfer roller cover 131 a is provided so as to face the paper transport path PP, and is configured to guide the paper between the photosensitive drum 133 and the transfer roller 135.

  In the process case 131, a cleaning unit 136 for cleaning the peripheral surface of the photosensitive drum 133 is disposed. The cleaning unit 136 is disposed so as to come into contact with a peripheral surface of the photosensitive drum 133 on the downstream side in the rotation direction of the photosensitive drum 133 with respect to a position facing the transfer roller 135 across the paper transport path PP with a predetermined pressure. ing.

<Schematic configuration of developing cartridge>
The developing cartridge 132 is formed on the side of the photosensitive drum 133 so that the electrostatic latent image formed on the peripheral surface of the photosensitive drum 133 can be developed with toner and an image of the toner can be formed on the peripheral surface. Has been placed. That is, the developing cartridge 132 is configured to be able to supply toner to the peripheral surface of the photosensitive drum 133. The specific configuration is as follows.

  In the developing unit case 132a constituting the casing of the developing cartridge 132, toner as a developer for developing the electrostatic latent image is accommodated. Further, an opening 132a1 having a longitudinal direction in the paper width direction is formed at a position facing the photosensitive drum 133 in the developing unit case 132a. The developing roller 132b is accommodated in the developing unit case 132a so that approximately half of the peripheral surface thereof is exposed from the opening 132a1 to the outside of the developing unit case 132a. The rotation shaft 132b1 of the developing roller 132b is disposed along the paper width direction and is supported by the developing unit case 132a at a position near the opening 132a1 of the developing unit case 132a. The developing roller 132b is driven to rotate in the direction of the arrow in the figure at the time of image formation, so that the toner carried on the peripheral surface of the developing roller 132b can be supplied to the peripheral surface of the photosensitive drum 133. It has become.

  The supply roller 132c is disposed closer to the inside of the developing unit case 132a than the developing roller 132b. The supply roller 132c is disposed so as to contact or be pressed against the peripheral surface of the developing roller 132b. The supply roller 132c is supported by the developing unit case 132a so as to be rotatable about the rotation shaft 132c. The supply roller 132c is driven to rotate in the direction of the arrow in FIG. It can be carried on the surface.

  A blade 132d for adjusting the amount of toner and the amount of charge on the peripheral surface of the developing roller 132b is attached to the developing unit case 132a. Specifically, the blade 132d and the blade holder 132e are fixed to the developing unit case 132a by a plurality of screws (not shown), so that the blade 132d is supported so as to be sandwiched between the blade holder 132e and the developing unit case 132a. Yes. The blade 132d is formed by attaching a rubber chip to the tip of a blade body that is a thin metal plate material. The blade 132d is configured such that the amount of toner and the amount of charge on the peripheral surface of the developing roller 132b can be adjusted by bringing the rubber chip into contact with the peripheral surface of the developing roller 132b with a predetermined pressure by bending of the blade body. It is configured.

  In the developing unit case 132a, when the developing cartridge 132 is placed outside the laser printer 100 as a single unit (for example, when a new developing cartridge 132 before use is taken out of the packing material, A movable cover 132f for protecting the developing roller 132b is attached when the developing cartridge 132 is detached from the process case 131). The movable cover 132f is supported by the developing unit case 132a so as to be rotatable about the rotation shaft 132b1 of the developing roller 132b. A detailed configuration of the movable cover 132f will be described later.

  When the developing cartridge 132 having the above-described configuration is mounted on the process case 131, the developing cartridge 132 and the process case 131 are configured such that the peripheral surface of the developing roller 132b is in contact with or close to the peripheral surface of the photosensitive drum 133. ing.

<Configuration of scanner unit>
The scanner unit 140 is disposed in the upper part in the process case 131. The scanner unit 140 includes a scanner case 141, a polygon mirror 142, and reflecting mirrors 143, 144, and 145. The polygon mirror 142 is supported by a rotation drive shaft of a motor (not shown) fixed to the scanner case 141 so that the polygon mirror 142 can be driven to rotate at a predetermined rotation speed. The polygon mirror 142 can scan the laser beam along the paper width direction by reflecting the laser beam generated based on the image data by a laser light emitting unit (not shown) while being rotated by the motor. It is configured as follows. The reflecting mirrors 143, 144, and 145 are supported in the scanner case 141 so that the laser beam (dashed line) reflected by the polygon mirror 142 can be irradiated onto the peripheral surface of the photosensitive drum 133.

<Configuration of paper feed unit>
The paper feed unit 150 includes a paper feed roller 151, a paper dust removing roller 152, paper guides 153 and 154, and a registration roller 155. The paper feed roller 151 is rotatably supported by the main frame (not shown) of the main body 110. The paper feed roller 151 is disposed to face the separation pad 125 so that the peripheral surface thereof is in contact with the separation pad 125 with a predetermined pressure. The paper dust removing roller 152 is rotatably supported by the main frame on the front side of the separation pad 125 (on the downstream side in the rotation direction of the paper feeding roller 151 during paper feeding). The paper dust removing roller 152 is arranged so that its peripheral surface is in contact with the paper feeding roller 151. The sheet guide 153 is a member for guiding the sheet so that the sheet can be conveyed along the sheet conveyance path PP, and is arranged at an appropriate position and number in the main body 110. The registration roller 155 is a pair of rollers for adjusting the orientation and conveyance timing of the sheet, and is disposed on the upstream side in the sheet conveyance direction from the position where the photosensitive drum 133 and the transfer roller 135 face each other.

<Configuration of fixing unit>
The fixing unit 160 is disposed on the downstream side in the paper transport direction from the position where the photosensitive drum 133 and the transfer roller 135 face each other. The fixing unit 160 includes a fixing unit cover 161, a heat roller 162, and a pressure roller 163. The fixing unit cover 161 is a member interposed between the process cartridge 130 and the heat roller 162 and the pressure roller 163 so that the process cartridge 130 is not heated as much as possible. In the fixing unit cover 161, a sheet inlet 161a and a sheet outlet 161b are formed at positions intersecting with the sheet conveyance path PP. The heat roller 162 contains a halogen lamp in a metal cylinder whose surface has been released from the mold, and the fixing unit cover 161 can be rotated in the direction of the arrow (clockwise) by a motor (not shown). It is supported so that it can rotate inside. The pressure roller 163 is a roller made of silicon rubber, and can be rotated in the arrow direction (counterclockwise) in the drawing by being driven by the heat roller 162 while being pressed with a predetermined pressure against the heat roller 162. The fixing unit cover 161 is rotatably supported.

<Configuration of paper discharge unit>
The paper discharge unit 170 includes a paper conveyance roller 171, a paper discharge roller 172, and a paper guide 173. The paper transport roller 171 is a pair of rollers that are rotationally driven by a motor (not shown), and is disposed in the vicinity of the paper outlet 161 b of the fixing unit 160. The paper discharge roller 172 is a pair of rollers that are rotationally driven by a motor (not shown), and is disposed in the vicinity of the paper discharge port 111c. The paper guide 173 is a member for guiding paper from the paper transport roller 171 to the paper discharge roller 172 along the paper transport path PP.

<Detailed configuration around the movable cover of the developer cartridge>
FIG. 3 is a perspective view of the developing cartridge 132 shown in FIG. Here, FIG. 3A shows a state in which the developing cartridge 132 is detached from the process case 131 of the process cartridge 130 (hereinafter referred to as “detached state”). FIG. 3B shows a state where the developing cartridge 132 is attached to the process case 131 (hereinafter referred to as “attached state”). FIG. 4 is a side sectional view of the movable cover 132f. Here, FIG. 4 (a) corresponds to the detaching state of FIG. 3 (a), and FIG. 4 (b) corresponds to the mounting state of FIG. 3 (b). Further, FIG. 5 is a perspective view of the process cartridge 130 in a state where the developing cartridge 132 shown in FIG. 3 is mounted.

  Referring first to FIG. 3, the developing unit case 132a includes a pair of side frames 132a2 that support a rotating shaft such as the rotating shaft 132b1 of the developing roller 132b. An opening 132a1 shown in FIG. 1 is formed at the end of the side frame 132a2 on the downstream side in the paper conveyance direction, and the rotation shaft 132b1 of the developing roller 132b is supported so as to be spanned. . By the end of the rotating shaft 132b1, the movable cover 132f can be rotated between the first position in the detached state shown in FIG. 3A and the second position in the attached state shown in FIG. 3B. It is supported by. Here, the “first position” covers the peripheral surface of the developing roller 132b exposed from the opening 132a1 (see FIG. 1) of the developing unit case 132a, as shown in FIG. 3A. Thus, it is a position facing the peripheral surface. Further, the “second position” refers to the peripheral surface of the developing roller 132b exposed from the opening 132a1 (see FIG. 1) of the developing unit case 132a, as shown in FIGS. 1 and 3B. It is the position below. With the position of the movable cover 132f set to the second position, the peripheral surface of the developing roller 132b exposed from the opening 132a1 (see FIG. 1) of the developing unit case 132a faces the outside of the developing cartridge 132. The movable cover 132f is configured so as to be exposed.

<< Detailed configuration of movable cover >>
The movable cover 132f includes a cover main body 132f1 that constitutes a housing portion of the present invention, and a hook 132f2 provided so as to extend downward from the cover main body 132f1 in FIG. As shown in FIG. 3A, a plurality of guide ribs 132f3 are formed on the outer surface of the cover main body 132f1. The guide rib 132f3 is erected so as to face the sheet conveyance path PP shown in FIG. 1 when the position of the movable cover 132f is set to the second position described above.

  As shown in FIG. 4, the cover main body 132f1 includes a first outer plate 132f4, a top plate 132f5, a second outer plate 132f6, and an inner plate 132f7. As shown in FIGS. 3A and 4A, the first outer plate 132f4 is a plate facing the peripheral surface so as to cover the peripheral surface of the developing roller 132b at the first position. It is comprised from the shaped member. The above-described guide rib 132f3 is erected on the outer surface of the first outer plate 132f4.

  As shown in FIG. 4A, the top plate 132f5 is provided so as to extend from the end portion (the upper end portion in FIG. 4A) of the first outer plate 132f4, and the first position. It consists of the plate-shaped member which comprises the top plate of the cover main body 132f1. The second outer plate 132f6 is made of a plate-like member that forms the bottom plate of the cover main body 132f1 at the first position. The inner plate 132f7 is made of a plate-like member provided so as to extend upward from the end portion of the second outer plate 132f6 at the first position.

  Further, as shown in FIG. 4B, the first outer plate 132f4 constitutes the bottom plate of the cover main body 132f1 at the second position. The second outer plate 132f6 is connected to the first outer plate 132f4 so as to extend upward from the end portion of the first outer plate 132f4 at the second position. The inner plate 132f7 is disposed at a position that does not face the exposed peripheral surface of the developing roller 132b at the second position. An opening 132f8 is formed by the tip of the top plate 132f5 and the tip of the inner plate 132f7.

  The cover main body 132f1 having such a configuration causes the toner falling from above the opening 132f8 at the second position to pass through the first outer plate 132f4, the top plate 132f5, the second outer plate 132f6, and the inner plate. It can be accommodated in a box-shaped space formed by 132f7.

<< Examples of holding mechanism, moving mechanism, and damper mechanism >>
As shown in FIG. 5, the hook 132 f 2 is engaged with an engagement hole 131 f formed in the process case 131 in a state where the developing cartridge 132 is mounted in the process case 131 of the process cartridge 130. The movable cover 132f is configured to be held at the second position shown in FIG. That is, in the present embodiment, a holding mechanism that holds the movable cover 132f at the second position is configured by the hook 132f2.

  Referring to FIG. 3 again, the cover body 132f1 is configured to be wider than the width in the longitudinal direction (paper width direction) of the developing roller 132b. That is, the cover main body 132f1 is configured to reliably store the toner leaked from the central portion and both end portions in the longitudinal direction of the developing roller 132b at the second position.

  Bearing plates 132f9 are formed at both ends in the longitudinal direction (paper width direction) of the cover main body 132f1 so as to penetrate the rotation shaft 132b1 of the developing roller 132b.

  The movable cover 132f having the above-described configuration is integrally formed by synthetic resin injection molding. The movable cover 132f is integrally formed with a cylindrical collar 132g that covers the end of the rotation shaft 132b1 of the developing roller 132b. The collar 132g is formed in a recess formed in the process case 131 so that the process case 131 is not worn by friction with the metal rotating shaft 132b1 when the developing cartridge 132 and the process case 131 are attached and detached. It is a member engaged with each other.

  A side cover 132h is attached to the outside of the side frame 132a2. The rotation shaft 132b1 of the developing roller 132b is passed through the side cover 132h. The side cover 132h is formed such that the outer surface thereof is in contact with the bearing plate 132f9 of the movable cover 132f, and the side cover 132h is moved away from the outer surface by the rotation between the first position and the second position of the movable cover 132f. The bearing plate 132f9 is configured to slide. In addition, a coil spring 132k is stretched between the sliding portion above the side cover 132h and the movable cover 132f (top plate 132f5 in FIG. 4). The coil spring 132k has a natural length in the state shown in FIG. 3A, and the movable cover 132f is moved from the second position shown in FIG. It is configured to be moved by an elastic force toward the first position shown in a). That is, in the present embodiment, a moving mechanism that moves the movable cover 132f from the second position toward the first position is configured by the coil spring 132k.

  In the developing cartridge 132 of the present embodiment, the tip of the top plate 132f5 (see FIG. 4) of the movable cover 132f is not attached to another device or cartridge as shown in FIG. By contacting the side frame 132a2, the movable cover 132f can be held in the state shown in FIG. That is, in the present embodiment, a holding mechanism that holds the movable cover 132f in the first position is configured by the tip of the top plate 132f5 of the movable cover 132f and the side frame 132a2.

  The sliding portion between the outer surface of the side cover 132h and the bearing plate 132f9 is filled with grease G. The grease G is made of a material having a relatively high viscosity to such an extent that the acceleration applied to the movable cover 132f when the movable cover 132f moves from the second position toward the first position can be attenuated. ing. That is, in the present embodiment, the side cover 132h, the bearing plate 132f9, and the grease G constitute a damper mechanism that attenuates acceleration when the movable cover 132f moves from the second position to the first position. ing.

<Operation / Effects of Configuration of Embodiment>
Next, how the developing cartridge 132 is attached to the process case 131 of the process cartridge 130 and how the developing cartridge 132 is detached from the process case 131 will be described with reference to the drawings.

  The developer cartridge 132 in a new state before use before being attached to the process case 131 is in the detachable state shown in FIG. In this detachable state, the movable cover 132f is held at the first position. That is, the peripheral surface of the developing roller 132b is covered (protected) by the movable cover 132f. Accordingly, the developing roller 132b can be protected so that the peripheral surface of the developing roller 132b is not damaged from the time when the developing cartridge 132 is manufactured until the user removes the developing cartridge 132 from the packing material. In addition, in the detached state, the peripheral surface of the developing roller 132b before use comes into contact with the user's hand, clothes, and the like, so that dirt and foreign matter can be suppressed from attaching to the peripheral surface.

  In the detached state, the hook 132f2 protrudes downward from the cover body 132f1 of the movable cover 132f. Here, the developing cartridge 132 is inserted into the process case 131 obliquely downward so that the tip of the hook 132f2 is engaged with the engagement hole 131f of the process case 131. Then, the movable cover 132f rotates against the elastic force of the coil spring 132k until it reaches the state shown in FIG. 3B, and the hook 132f2 is engaged with the engagement hole 131f. As a result, as shown in FIG. 5, the developing cartridge 132 is attached to the process case 131 with the movable cover 132f being held at the second position.

  In the mounted state in which the developing cartridge 132 is mounted on the process case 131 of the process cartridge 130, the cover main body 132f1 of the movable cover 132f has the opening 132f8 (see FIG. 4B) facing upward and the developing unit. It is located below the peripheral surface of the developing roller 132b exposed from the opening 132a1 of the case 132a. Accordingly, the movable cover 132f, which is necessary for protecting the developing roller 132b in the detached state and unnecessary in the mounted state (when the image forming operation is performed), has the developing cartridge 132 in the mounted state. Can be retracted from the developing position (position where the developing roller 132b and the photosensitive drum 133 face each other). Further, the developer leaked from the gap between the opening 132a1 and the developing roller 132b during the image forming operation by the cover main body 132f1 passes through the opening 132f8 in FIG. 4B, and the first outer plate 132f4 and the top plate. It can be accommodated in a box-like space formed by 132f5, the second outer plate 132f6, and the inner plate 132f7. The box-like space is formed wider than the width of the developing roller 132b in the paper width direction. Therefore, scattering of the developer leaking from the gaps in the main body 110 of the laser printer 100 is suppressed, and the developer can be effectively collected.

  In the mounted state, as shown in FIG. 1, the position of the movable cover 132f is set to the second position below the developing roller 132b, so that the peripheral surface of the developing roller 132b is a photosensitive drum. In addition, the movable cover 132f is held so that the outer surface of the movable cover 132f faces the paper transport path PP. Since the guide rib 132f3 for guiding the sheet conveyance is formed on the outer surface of the movable cover 132f, the sheet can smoothly pass through the process cartridge 130.

  Thereafter, the developer cartridge 132 is detached from the process case 131 (for example, when the developer cartridge 132 is replaced due to a small amount of developer built-in or when a paper jam is processed), and the main body 110 of the laser printer 100 is removed. 3f, the movable cover 132f is moved from the second position shown in FIG. 3B by the elastic force of the coil spring 132k, and the first cover shown in FIG. Move to the position. Therefore, the movable cover 132f is moved simply by detaching the developing cartridge 132 from the process case 131 of the process cartridge 130 without manually operating the movable cover 132f by the user. Therefore, the user's fingers can be prevented from being stained with toner by operating the movable cover 132f. In addition, when the developing cartridge 132 is taken out of the laser printer 100 for replacement of the developing cartridge 132, paper jam processing, or the like (the detaching state), the developing roller 132b is effectively protected from scratches and foreign matter adhesion. Can be done.

  As described above, in the configuration of the present embodiment, the movable cover 132f that is necessary for protecting the developing roller 132b in the detached state and is unnecessary in the mounted state is always mounted on the developing cartridge 132. However, it can move to an appropriate position according to the mounting state and the detaching state. That is, the movable cover 132f necessary for performing the toner refill for collecting the used developing cartridge 132 and refilling the toner again is mounted on the developing cartridge 132 even in the mounted state. Therefore, according to the configuration of the present embodiment, it is possible to prevent the movable cover 132f from being lost or discarded when toner refilling of the developing cartridge 132 is performed. The movable cover 132f can be reused from the time when the developing cartridge 132 is collected to the time when the refilled developing cartridge 132 is distributed. Therefore, the toner refill of the developing cartridge 132 can be performed more efficiently.

  When the movable cover 132f moves from the second position to the first position by the elastic force of the coil spring 132k, the outer surface of the side cover 132h and the bearing plate 132f9 slide. At this time, since the sliding portion is filled with the grease G having a high viscosity, the acceleration when the movable cover 132f moves from the second position to the first position is attenuated. Thereby, the toner accommodated by the movable cover 132f during the movement can be suppressed.

  When the used developing cartridge 132 is taken out of the main body 110 of the laser printer 100, as shown in FIG. 4A, the first outer plate 132f6 constituting the bottom plate is exposed from both ends. The outer plate 132f4 and the inner plate 132f7 protrude upward. Thereby, in the detaching state, the toner is held in a box-shaped space surrounded by the first outer plate 132f4, the second outer plate 132f6, and the inner plate 132f7. Therefore, the toner stored by the movable cover 132f can be suppressed from being scattered.

<Suggestion of modification>
Note that, as described above, the above-described embodiment is merely an example of the embodiment of the present invention that the applicant considered to be the best at the time of filing of the present application, and the present invention is not limited to the above-described embodiment. The present invention is not limited to the embodiments, and various modifications can be made without departing from the essential part of the present invention. Hereinafter, some modifications will be exemplified. Needless to say, the modifications are not limited to the following.

(I) The image forming apparatus to which the present invention is applied is not limited to a laser printer. The developing cartridge may be detachable from the main body of the laser printer provided with the photosensitive drum.

(Ii) The collar 132g in the above-described embodiment may be separate from the movable cover 132f. In this case, for example, the collar 132g may be integrated with the side cover 132h.

(Iii) In the above-described embodiment, the cross-sectional shape of the movable cover 132f shown in FIG. 4 is applied over substantially the entire length in the longitudinal direction of the movable cover 132f. But the said cross-sectional shape may be applied to a part of full length in the longitudinal direction of the movable cover 132f. For example, it may be applied only to both end portions of the developing roller 132b where toner leakage is likely to occur normally. Alternatively, it may be applied only to the substantially central portion in the longitudinal direction of the developing roller 132b. Furthermore, it may be applied only to the both end portions and the substantially central portion described above.

(Iv) In the above-described embodiment, the engaging portion with which the hook 132f2 formed on the movable cover 132f is engaged is configured by the engaging hole 131f formed in the process case 131 of the process cartridge 130. However, the engaging portion may be formed in the main body 110 of the laser printer 100.

(V) In the above-described embodiment, the movable cover 132f is biased so as to move from the second position to the first position. However, the movable cover 132f may be biased so as to move from the first position to the second position.

(Vi) In the above-described embodiment, the damper mechanism that attenuates the acceleration when the movable cover 132f moves from the second position to the first position is the side cover 132h, the bearing plate 132f9, and the grease G. Was composed. In addition, the damper mechanism can be realized by various structures such as a small synthetic resin oil damper mechanism used for a suspension of a radio control automobile model.

(Vii) In the above-described embodiment, the movable cover 132f is configured to be held at the first position when the movable cover 132f contacts the side frame 132a2. However, instead of this, the movable cover 132f is configured to be held at the first position by abutting against other members (for example, the blade holder 132e and the side cover 132h). May be.

(Viii) A rotatable roller or the like may be used in place of the guide ribs 132f3 and the guide ribs that can be formed on the surfaces of the paper guides 153 and 154 facing the paper transport path PP in the above-described embodiment.

1 is a cross-sectional view illustrating a schematic configuration of a laser printer according to an embodiment of the present invention. It is a figure which shows the mode of the attachment or detachment of the process cartridge in the laser printer shown in FIG. FIG. 2 is a perspective view illustrating an appearance of the developing cartridge illustrated in FIG. 1. It is a sectional side view of the movable cover shown in FIG. FIG. 2 is a perspective view illustrating an appearance of a process cartridge illustrated in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Laser printer, 110 ... Main-body part, 130 ... Process cartridge,
131 ... Process case, 132 ... Developing cartridge, 132a ... Developing unit case,
132a1 ... opening, 132a2 ... side frame, 132b ... developing roller,
132b1 ... rotating shaft, 132f ... movable cover, 132f1 ... cover body,
132f2 ... hook, 132k ... coil spring, 133 ... photosensitive drum,
G ... Grease

Claims (12)

In a developing cartridge configured to be able to develop an electrostatic latent image formed on an image carrier provided in an image forming apparatus and detachable from the image forming apparatus,
A developing roller capable of carrying a developer for developing the electrostatic latent image on a peripheral surface;
An opening that exposes the peripheral surface of the developing roller to the outside, and a developing unit case that accommodates the developing roller while rotatably supporting the developing roller;
A first position facing the peripheral surface so as to cover the peripheral surface of the developing roller exposed from the opening, and a second position exposing the peripheral surface to the outside by being positioned below the peripheral surface A movable cover supported by the developing unit case so as to be movable between
The developer is provided in the movable cover, and stores the developer leaked from the gap between the opening and the developing roller at the second position, and stores the developer stored at the second position. A storage portion that holds the liquid so as not to leak outside at the position of 1 ;
With
The accommodating portion is orthogonal to the rotation center axis of the developing roller so that the developer accommodated at the second position does not leak outside when the movable cover is set at the first position. The cross-sectional shape by the surface to be formed is configured in a box shape having an opening,
The developing cartridge according to claim 1, wherein the opening is formed at the second position so as to allow the developer falling from above to pass therethrough and be accommodated in the box. The developing cartridge according to claim 1,
The accommodating portion is
Forming a bottom plate of the housing portion at the second position, a first outer plate facing the developing roller at the first position;
A bottom plate of the housing portion is configured at the first position, and a second plate is provided connected to the first outer plate so as to extend upward from an end portion of the first outer plate at the second position. Two skins,
An inner portion provided at the first position so as to extend upward from an end portion of the second outer plate and at a position not facing the exposed peripheral surface of the developing roller at the second position. The board,
A developing cartridge comprising: The developing cartridge according to claim 1, wherein
The developing cartridge according to claim 1, wherein the accommodating portion is formed to have a width wider than a width of the developing roller in a rotation center axis direction. The developing cartridge according to any one of claims 1 to 3,
The developing cartridge, wherein the movable cover is supported so as to be rotatable about a rotation center axis of the developing roller. In a process cartridge that is detachable from an image forming apparatus,
An image carrier on which an electrostatic latent image is formed;
A process case for accommodating the image carrier;
A developing cartridge that is detachable from the process case;
With
The developing cartridge is
A developing roller capable of carrying a developer for developing the electrostatic latent image on a peripheral surface;
An opening that exposes the peripheral surface of the developing roller to the outside, and a developing unit case that accommodates the developing roller while rotatably supporting the developing roller;
A first position facing the peripheral surface so as to cover the peripheral surface of the developing roller, and the peripheral surface by being positioned below the peripheral surface in a state where the developing cartridge is mounted on the process case A movable cover supported by the developing unit case so as to be movable between a second position exposed toward the image carrier,
The developer is provided on the movable cover, and stores the developer leaked from the gap between the opening and the developing roller at the second position, and stores the developer stored at the second position. A storage portion that holds the liquid so as not to leak outside at the position of 1 ;
With
The accommodating portion is orthogonal to the rotation center axis of the developing roller so that the developer accommodated at the second position does not leak outside when the movable cover is set at the first position. The cross-sectional shape by the surface to be formed is configured in a box shape having an opening,
The process cartridge is characterized in that, at the second position, the process cartridge is formed so as to allow the developer falling from above to pass therethrough and be accommodated in the box. The process cartridge according to claim 5,
The accommodating portion is
Forming a bottom plate of the housing portion at the second position, a first outer plate facing the developing roller at the first position;
A bottom plate of the housing portion is configured at the first position, and a second plate is provided connected to the first outer plate so as to extend upward from an end portion of the first outer plate at the second position. Two skins,
An inner portion provided at the first position so as to extend upward from an end portion of the second outer plate and at a position not facing the exposed peripheral surface of the developing roller at the second position. The board,
A process cartridge comprising: The process cartridge according to claim 5 or 6,
The process cartridge according to claim 1, wherein the accommodating portion is formed to have a width wider than a width of the developing roller in a rotation center axis direction. The developing cartridge according to any one of claims 5 to 7,
The process cartridge, wherein the movable cover is supported rotatably about a rotation center axis of the developing roller. In an image forming apparatus that forms an image with a developer,
An image carrier on which an electrostatic latent image is formed;
A developing cartridge detachably mounted opposite to the image carrier;
With
The developing cartridge is
A developing roller that is disposed opposite to the image carrier and capable of carrying a developer for developing the electrostatic latent image on a peripheral surface;
An opening that exposes the peripheral surface of the developing roller to the outside, and a developing unit case that accommodates the developing roller while rotatably supporting the developing roller;
A first position facing the peripheral surface so as to cover the peripheral surface of the developing roller, and a second position exposing the peripheral surface toward the image carrier by being positioned below the peripheral surface. A movable cover supported by the developing unit case so as to be movable between,
The developer is provided on the movable cover, and stores the developer leaked from the gap between the opening and the developing roller at the second position, and stores the developer stored at the second position. A storage portion that holds the liquid so as not to leak outside at the position of 1 ;
With
The accommodating portion is orthogonal to the rotation center axis of the developing roller so that the developer accommodated at the second position does not leak outside when the movable cover is set at the first position. The cross-sectional shape by the surface to be formed is configured in a box shape having an opening,
The image forming apparatus according to claim 1, wherein the opening is formed at the second position so as to allow the developer dropped from above to pass therethrough and be accommodated in the box. The image forming apparatus according to claim 9, wherein
The accommodating portion is
Forming a bottom plate of the housing portion at the second position, a first outer plate facing the developing roller at the first position;
A bottom plate of the housing portion is configured at the first position, and a second plate is provided connected to the first outer plate so as to extend upward from an end portion of the first outer plate at the second position. Two skins,
An inner portion provided at the first position so as to extend upward from an end portion of the second outer plate and at a position not facing the exposed peripheral surface of the developing roller at the second position. The board,
An image forming apparatus comprising: The image forming apparatus according to claim 9 or 10,
The image forming apparatus according to claim 1, wherein the accommodating portion is formed to have a width wider than a width of the developing roller in a rotation center axis direction. The image forming apparatus according to any one of claims 9 to 11,
The image forming apparatus, wherein the movable cover is supported so as to be rotatable about a rotation center axis of the developing roller.

Images