JP3628869B2 - Process cartridge shutter mechanism, process cartridge using the same, and image forming apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shutter mechanism of a process cartridge in which a photosensitive drum and a developing roller are housed in a case, a process cartridge using the shutter mechanism , and an image forming apparatus using the same .
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, there is a process cartridge in which a photosensitive drum and a developing roller are housed in one case, and the photosensitive drum and the developing roller are exchanged simultaneously for each case. It is popular. In such a process cartridge, an opening is formed in the case for contacting the photosensitive drum with a transfer member in the image forming apparatus when the process cartridge is mounted in the image forming apparatus.
[0003]
When a hand or an object touches the photosensitive drum, image formation at that portion becomes defective, and streaks or the like are generated in the image transferred to transfer paper or the like. Therefore, a process of providing a shutter that covers the opening of the process cartridge, covering the opening with the shutter before mounting the process cartridge in the image forming apparatus, and immediately before mounting the process cartridge in the image forming apparatus A process cartridge in which the shutter is opened is known.
[0004]
[Problems to be solved by the invention]
However, in recent years, the process cartridge is also downsized due to the downsizing of the image forming apparatus, and various mechanisms are arranged close to each other around the process cartridge mounted in the image forming apparatus.
[0005]
For this reason, it is difficult to provide a shutter that covers the opening in a process cartridge used in a downsized image forming apparatus.
[0006]
SUMMARY An advantage of some aspects of the invention is that it provides a shutter mechanism for a process cartridge used in a downsized image forming apparatus and a method for opening the shutter mechanism.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, the photosensitive drum and the developing roller are accommodated in a case, and the opening for allowing the photosensitive drum to face a transfer member in the image forming apparatus when mounted in the image forming apparatus. In the process cartridge formed in the case, one end is pivotally connected to the case and the other end is pivotally connected to a shutter member, and the shutter member closes the opening and the opening. And an urging member that urges the shutter member in a direction in which the shutter member is pressed against the outer peripheral surface of the case. Therefore, when the arm member is rotated and the shutter member is moved from the closed position to the open position, the shutter member is kept pressed against the outer peripheral surface of the case. For this reason, the shutter member is always positioned close to the outer peripheral surface of the case, and the installation space for the shutter member is reduced.
[0010]
Further, a gear for transmitting rotational driving force is provided at one end of the photosensitive drum, and a flange is formed at the other end, and the outer diameter of these gear and flange is made larger than the outer diameter of the photosensitive drum. Therefore, when the shutter member moves, both end portions of the shutter member are in sliding contact with the outer peripheral surface of the gear and the flange, and the contact between the shutter member and the photosensitive drum is prevented.
[0011]
And the protrusion which slidably contacts to the outer peripheral surface of a gear and a flange was formed in the front end side both ends of a shutter member. Therefore, when the shutter member moves, a gap between the front end portion of the shutter member and the photosensitive drum is increased, and contact between the front end portion of the shutter member and the photosensitive drum is further prevented.
In addition, the front-end | tip part of a shutter member means the front part of the moving direction when a shutter member moves toward a closed position.
[0012]
According to a second aspect of the present invention, in the shutter mechanism of the process cartridge according to the first aspect of the present invention, a rounded portion of a size that does not mesh with the gear is formed at the tip of the protrusion that is in sliding contact with the outer peripheral surface of the gear. Therefore, even when the protrusion slides on the outer peripheral surface of the gear when moving the shutter member, the movement of the shutter member is performed smoothly without the protrusion engaging with the gear and hindering the movement operation.
[0013]
According to a third aspect of the present invention, in the shutter mechanism of the process cartridge according to the first aspect of the present invention, the tip of the shutter member that has moved to the closed position is overlapped with the peripheral edge of the opening. Therefore, when the shutter member is moved to the closed position, even if an external force is applied to the shutter member, the shutter member does not bend to a position where it comes into contact with the photosensitive drum, and the photosensitive member is caused by the shutter member coming into contact with the photosensitive drum. Damage to the drum surface is prevented.
[0014]
According to a fourth aspect of the present invention, in the shutter mechanism of the process cartridge according to the first aspect, a handle having a grip opening for inserting a fingertip is formed on the upper surface of the case and is mounted in the image forming apparatus. The rear end portion of the shutter member moved to the open position in the process cartridge is prevented from protruding from the holding opening. Therefore, when the process cartridge is attached to and detached from the image forming apparatus by holding the handle, the fingertip does not hit the rear end of the shutter member, and the process cartridge can be attached and detached smoothly.
The rear end portion of the shutter member refers to a front portion in the moving direction when the shutter member moves toward the open position.
According to a fifth aspect of the present invention, the photosensitive drum and the developing roller are housed in a case, and the opening for allowing the photosensitive drum to face a transfer member in the image forming apparatus when mounted in the image forming apparatus. The process cartridge formed in the case includes the shutter mechanism according to any one of claims 1 to 4.
According to a sixth aspect of the present invention, in an image forming apparatus for performing image formation by electrophotography, the process cartridge according to the fifth aspect is provided.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. First, the internal structure of the image forming apparatus using the process cartridge of the present invention will be described with reference to FIG. An image reading device 2 for reading an image of a document is mounted on the upper portion of the main body case 1 of the image forming apparatus, and a process cartridge 3 is detachably mounted in the main body case 1. Below the process cartridge 3, a paper conveyance path 4 for guiding the transfer paper is formed.
[0016]
The image reading device 2 includes an image reading unit 5 and a document tray 6 that supplies a document to the image reading unit 5, and the document tray 6 has a horizontal position indicated by a solid line around a fulcrum shaft 7. It is supported so that it can rotate to the standing position indicated by the two-dot chain line. The document tray 6 is configured to be stabilized at a horizontal position indicated by a solid line and an upright position indicated by a two-dot chain line by a stopper (not shown).
[0017]
The process cartridge 3 contains various process members in a case 10 in which a photoconductor case 8 and a developing case 9 are connected. In the photoconductor case 8, a photoconductive drum 11 that is driven to rotate, A charging roller 12 and the like for uniformly charging the periphery of the photosensitive drum 11 are accommodated. In the developing case 9, a developer accommodating portion 13 that accommodates the developer is integrally formed, and an agitator 14 that agitates the developer in the developer accommodating portion 13 and development that is in contact with the outer peripheral surface of the photosensitive drum 11. A roller 15, a replenishing roller 16 that replenishes the developer in the developer storage unit 13 to the developing roller 15, a developing blade 17 that contacts the outer peripheral surface of the developing roller 15, and the like are stored.
[0018]
Around the process cartridge 3 in the main body case 1, a developer is supplied from a laser writing unit 18 for forming an electrostatic latent image on the outer peripheral surface of the photosensitive drum 11 and the developing roller 15, and a visible image is formed. A transfer roller 19 that is a transfer member that transfers the toner image on the photosensitive drum 11 onto the transfer paper, a paper feed tray 20 that supports the transfer paper in a state where the transfer paper is placed obliquely, and a paper feed roller that feeds the transfer paper 21 is provided with a fixing unit 22 for fixing the toner image transferred to the fed transfer paper, a receiving plate 23 for discharging the transfer paper that has passed through the fixing unit 22, and the like. The case 10 is formed with an opening 24 for contacting the photosensitive drum 11 and the transfer roller 19 to face each other.
[0019]
Further, two guides 25, 26 for attaching / detaching the process cartridge 3 to / from the main body case 1 are formed on the side plate in the main body case 1 on the left and right sides. Two guide pins 27, 28 that engage with the guides 25, 26 are formed on both the left and right side surfaces of the case 10. The process cartridge 3 is attached / detached from the receiving plate 23 side, and when attaching / detaching, the receiving plate 23 is rotated to open the attaching / detaching side.
[0020]
Next, the process cartridge 3 is provided with a shutter member 29 for opening and closing the opening 24, and the mounting structure of the shutter member 29 will be described in detail with reference to FIGS. One end of an arm member 30 is rotatably connected to the left and right sides of the case 10 by a support shaft 31, the other end of the left and right arm members 30 is connected by a connecting frame 30a, and the other end of the arm member 30 is connected to the other end of the arm member 30. The shutter member 29 is rotatably connected. A spring 32, which is a biasing member, is attached to the connecting portion of the shutter member 29 to the arm member 30, and the shutter member 29 is biased by the spring 32 in a direction to be pressed against the outer peripheral surface of the case 10. . A spring 33 for urging the arm member 30 in a direction in which the shutter member 29 moves to a closing position for closing the opening 24 is attached to a connecting portion of the arm member 30 to the case 10. When the shutter member 29 is moved to the closing position, the distal end portion of the shutter member 29 overlaps the peripheral edge portion of the opening 24 as shown in FIGS. The front end portion of the shutter member 29 here refers to a front portion in the moving direction when the shutter member 29 moves toward the closing position.
[0021]
The arm member 30 is formed with a protrusion 34 that engages with the guide 26 when the process cartridge 3 is attached to and detached from the main body case 1. When the process cartridge 3 is mounted in the main body case 1, the projection 34 engaged with the guide 26 receives a force from the guide 26, and the arm member 30 rotates so as to move the shutter member 29 from the closed position to the open position.
[0022]
Here, the positional relationship between the photosensitive drum 11 exposed from the opening 24 and the shutter member 29 will be described with reference to FIGS. First, as shown in FIG. 8, a gear 35 for transmitting a rotational driving force to the photosensitive drum 11 is fixed to one end of the photosensitive drum 11. A flange 36 is fixed to the other end of the photosensitive drum 11. The outer diameter of the gear 35 and the flange 36 is larger than the outer diameter of the photosensitive drum 11. Next, as shown in FIG. 9, projections 37 a and 37 b are formed on both ends of the shutter member 29 on the front end side so as to be in sliding contact with the outer peripheral surfaces of the gear 35 and the flange 36. A rounded portion 38 having a size that does not mesh with the gear 35 is formed at the tip of the protrusion 37 a that is in sliding contact with the outer peripheral surface of the gear 35. Due to such a structure, the moving shutter member 29 does not contact the photosensitive drum 11, but rather a large gap is generated between the shutter member 29 and the photosensitive drum 11.
[0023]
Next, a handle 39 is formed on the upper surface of the case 10 to hold the process cartridge 3 when the process cartridge 3 is attached to or detached from the main body case 1, and the handle 39 holds the handle 39 as shown in FIG. A grip opening 40 is formed through which a fingertip is inserted. In the process cartridge 3 mounted in the main body case 1, the shutter member 29 moves to the open position shown in FIG. 9 as the arm member 30 rotates. When the shutter member 29 is moved to the open position, the rear end portion of the shutter member 29 and the connecting frame 30a are positioned so as not to protrude from the holding opening 40. The rear end portion of the shutter member 29 refers to a front portion in the moving direction when the shutter member 29 moves toward the open position.
[0024]
In such a configuration, FIGS. 1 and 2 show an initial state of an operation for mounting the process cartridge 3 in the main body case 1. In FIG. 1, only one guide pin 27 is fitted to the guide 25. In FIG. 2, the process guide 3 is slightly pushed into the main body case 1 from the state shown in FIG. In these states, the arm member 30 is rotated to a predetermined position by the urging force of the spring 33, and the shutter member 29 closes the opening 24. The shutter member 29 is maintained in a state of being pressed against the outer peripheral surface of the case 10 by the urging force of the spring 32, and the distal end portion of the shutter member 29 overlaps the peripheral edge portion of the opening 24.
[0025]
Accordingly, the opening 24 is closed by the shutter member 29 before the process cartridge 3 is mounted in the main body case 1, so that a finger or an object is accidentally inserted from the opening 24 to damage the photosensitive drum 11. It is prevented. Further, since the distal end portion of the shutter member 29 overlaps the peripheral edge portion of the opening 24, even when the shutter member 29 located at the closed position is pressed from the outside, the shutter member 29 is greatly bent and the photosensitive drum 11 is bent. It is prevented from touching.
[0026]
3 to 5 show a state after the protrusion 34 of the arm member 30 is engaged with the guide 26 by pushing the process cartridge 3 into the main body case 1. When the projection 34 is engaged with the guide 26, the projection 34 receives a force from the guide 26 as the process cartridge 3 is pushed into the main body case 1, and the arm member 30 moves around the support shaft 31 by the action of this force. The shutter member 29 gradually moves from the closed position of the opening 24 toward the open position. 3 shows a state where the opening 24 is half-opened, and FIGS. 4 and 5 show a state where the opening 24 is fully opened. In the process of moving the shutter member 29 toward the open position, the shutter member 29 is kept pressed against the outer peripheral surface of the case 10 by the biasing force of the spring 32.
[0027]
FIG. 6 shows a state in which the process cartridge 3 is mounted in the main body case 1, and the holding state of the process cartridge 3 is stabilized by the guide pins 27 and 28 engaging with the inner portions of the guides 25 and 26. The shutter member 29 moves to an open position where the opening 24 is opened, and is pressed against the outer peripheral surface of the case 10 by the biasing force of the spring 32. Accordingly, the shutter member 29 moves from the closed position of the opening 24 to the open position in the process of mounting the process cartridge 3 in the main body case 1, but the shutter member 29 is always pressed against the outer peripheral surface of the case 10 by the biasing force of the spring 32. Therefore, it is always located close to the outer peripheral surface of the case 10, and the installation space for the shutter member 29 can be made very small. Therefore, the shutter member 29 can be provided in the process cartridge 3 even when the entire image forming apparatus is downsized and the process cartridge 3 is downsized.
[0028]
Next, when the shutter member 29 moves from the closed position to the open position, the protrusions 37 a and 37 b formed at both end portions on the front end side of the shutter member 29 are in sliding contact with the outer peripheral surfaces of the gear 35 and the flange 36. Therefore, it is possible to make a large gap between the front end portion of the shutter member 29 and the outer peripheral surface of the photosensitive drum 11 in the process in which the shutter member 29 moves from the closed position to the open position. Contact with 29 can be prevented. Further, since the rounded portion 38 is formed at the distal end portion of the projection 37a slidably contacting the outer peripheral surface of the gear 35, the distal end portion of the projection 37a meshes with the gear 35 in the process of moving the shutter member 29, and the movement operation is hindered. Can be prevented. In particular, when the process cartridge 3 is once taken out of the main body case 1 for maintenance, the tip portion of the projection 37a is prevented from engaging with the gear 35 during the removal, and the shutter member 29 is brought into the closed position of the opening 24. Move smoothly.
[0029]
In the process cartridge 3 attached to the mounting position in the main body case 1, the rear end portion of the shutter member 29 moved to the open position and the connection frame 30 a are positioned so as not to protrude from the holding opening 40. Therefore, when the fingertip is inserted into the holding opening 40 and the handle 39 is gripped in order to attach or detach the process cartridge 3 to / from the main body case 1, the fingertip does not hit the rear end portion of the shutter member 29 or the connecting frame 30a. 3 can be attached and detached smoothly.
[0030]
【The invention's effect】
According to the shutter mechanism of the process cartridge of the first aspect of the present invention, when the arm member is rotated to move the shutter member from the closed position to the open position, the shutter member is kept pressed against the outer peripheral surface of the case. Therefore, the shutter member is always located close to the outer peripheral surface of the case, the installation space for the shutter member is reduced, and the entire image forming apparatus is reduced in size and the process cartridge is reduced in size. Even in the illustrated case, the process cartridge can be provided with a shutter member.
[0033]
In addition, a gear for transmitting rotational driving force is provided at one end of the photosensitive drum and a flange is formed at the other end, and the outer diameter of these gear and flange is made larger than the outer diameter of the photosensitive drum. When the shutter member moves, both ends of the shutter member are in sliding contact with the outer peripheral surface of the gear and the flange, so that the contact between the shutter member and the photosensitive drum during the movement of the shutter member can be prevented. It is possible to prevent the photosensitive drum from being damaged by contact.
[0034]
And since the protrusion which slide-contacts with the outer peripheral surface of a gear and a flange was formed in the both ends of the front end side of a shutter member, when a shutter member moves, the clearance gap between the front-end | tip part of a shutter member and a photosensitive drum is large. Thus, contact between the front end portion of the shutter member and the photosensitive drum during movement of the shutter member can be more reliably prevented.
[0035]
According to the second aspect of the invention, in the shutter mechanism of the process cartridge according to the first aspect, the rounded portion of a size that does not mesh with the gear is formed at the tip of the protrusion slidingly contacting the outer peripheral surface of the gear. Even if the protrusion slides on the outer peripheral surface of the gear when the shutter member moves, the movement of the shutter member can be performed smoothly without the protrusion engaging with the gear and hindering the movement operation.
[0036]
According to the third aspect of the present invention, in the shutter mechanism of the process cartridge according to the first aspect, the tip of the shutter member moved to the closed position is overlapped with the peripheral edge of the opening. Even when an external force is applied to the shutter member when the shutter member is moved to the closed position, the shutter member can be prevented from being bent and coming into contact with the photosensitive drum. Damage can be prevented.
[0037]
According to a fourth aspect of the present invention, in the shutter mechanism of the process cartridge according to the first aspect, the handle having a grip opening for inserting a fingertip is formed on the upper surface of the case and is mounted in the image forming apparatus. Since the rear end portion of the shutter member moved to the open position in the processed cartridge is prevented from protruding from the opening for gripping, the handle is gripped when the handle is gripped and the process cartridge is attached to and detached from the image forming apparatus. The fingertip does not hit the rear end of the shutter member, and the process cartridge can be smoothly attached and detached.
[Brief description of the drawings]
FIG. 1 is a side view showing a state in which only one guide pin is fitted to a guide for mounting a process cartridge in an image forming apparatus.
FIG. 2 is a side view showing a state in which a process cartridge is pushed into the main body case from the state of FIG. 1 and two guide pins are fitted to the guide.
3 is a side view showing a state in which the process cartridge is further pushed into the main body case from the state of FIG. 2 and the shutter member is moved toward the open position and the opening is half-opened. FIG.
4 is a side view showing a state in which the process cartridge is further pushed into the main body case from the state of FIG. 3 and the opening is fully opened. FIG.
5 is a side view showing a state in which the process cartridge is further pushed into the main body case from the state of FIG.
FIG. 6 is a side view showing a state where the mounting of the process cartridge is completed and the shutter member is moved to the open position.
FIG. 7 is a side view showing the internal structure of the image forming apparatus equipped with a process cartridge.
FIG. 8 is a front view of the photosensitive drum.
FIG. 9 is a front view showing the positional relationship between the grip holding opening and the rear end of the shutter member moved to the open position, and the shapes of the photosensitive drum and the shutter member.
[Explanation of symbols]
3 Process Cartridge 10 Case 11 Photosensitive Drum 15 Developing Roller 19 Transfer Member 24 Opening 26 Guide 29 Shutter Member 30 Arm Member 32 Energizing Member 34 Protrusion 35 Gear 36 Flange 37a, 37b Protrusion 38 Round Part 39 Handle 40 Gripping Opening

Claims (6)

A process cartridge in which a photosensitive drum and a developing roller are housed in a case, and an opening is formed in the case so that the photosensitive drum faces a transfer member in the image forming apparatus when the photosensitive drum and the developing roller are mounted in the image forming apparatus. In
One end is pivotally connected to the case and a shutter member is pivotally connected to the other end, and the shutter member is moved to a closing position for closing the opening and an opening position for opening the opening. An arm member;
A biasing member that biases the shutter member in a direction to press the shutter member against the outer peripheral surface of the case;
A gear for transmitting rotational driving force to one end of the photosensitive drum and a flange at the other end, and the outer diameter of the gear and the flange is larger than the outer diameter of the photosensitive drum. A process cartridge shutter mechanism, wherein protrusions that are in sliding contact with outer peripheral surfaces of the gear and the flange are formed at both ends of the front end side of the shutter member. 2. A shutter mechanism for a process cartridge according to claim 1, wherein a rounded portion having a size that does not mesh with the gear is formed at a tip portion of the protrusion that is in sliding contact with the outer peripheral surface of the gear. 2. A shutter mechanism for a process cartridge according to claim 1, wherein a front end portion of the shutter member moved to the closing position is overlapped with a peripheral edge portion of the opening portion. A grip having an opening for holding a fingertip is formed on the upper surface of the case, and a rear end of the shutter member moved to an open position in the process cartridge mounted in the image forming apparatus is used for the holding 2. A shutter mechanism for a process cartridge according to claim 1, wherein the shutter mechanism is not protruded from the opening. A process cartridge in which a photosensitive drum and a developing roller are housed in a case, and an opening is formed in the case so that the photosensitive drum faces a transfer member in the image forming apparatus when the photosensitive drum and the developing roller are mounted in the image forming apparatus. A process cartridge comprising the shutter mechanism according to claim 1. An image forming apparatus for performing image formation by electrophotography, comprising the process cartridge according to claim 5.

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