Patent Grant
10423119
Field of the Invention
The present embodiments relate to an image forming apparatus, such as a copying machine, a printer, and a facsimile, in which an exterior cover is opened and closed and a process cartridge mounted inside the apparatus is removed or replaced.
Description of the Related Art
In a certain configuration, an image bearing member (photosensitive drum) with a toner image formed thereon and an image forming unit (developing roller) are configured as a cartridge removably mounted on an image forming apparatus main body (apparatus main body), facilitating the replacement of consumables and other maintenance works.
With this cartridge of contact development type, development is performed by bringing the photosensitive drum into contact with the developing roller at the time of image formation. From the viewpoint of the life of a photosensitive drum and a developing roller, the contact development type is configured so that a pressing member of the apparatus main body presses a development container of the cartridge to switch the photosensitive drum and the developing roller between a contact state and a separation state.
Japanese Patent Application Laid-Open No. 2013-246247 discusses two different processes for mounting a cartridge in an apparatus main body: a process for moving the cartridge in the axial direction of a photosensitive drum (insertion process), and a process for moving the cartridge having a directional component perpendicularly intersecting with the axial direction and separating from a pressing member (positioning process). Japanese Patent Application Laid-Open No. 2013-246247 discusses a configuration corresponding to the insertion process and the positioning process, i.e., a configuration of a pressed portion of a development container pressed by a pressing member in a state where the pressing member and a cartridge have been mounted.
More specifically, in the configuration discussed in Japanese Patent Application Laid-Open No. 2013-246247, the pressed portion is disposed at a protruding portion protruding from the development container and positioned at a position distant to some extent from the root of the protruding portion protruding from the development container.
In the configuration discussed in Japanese Patent Application Laid-Open No. 2013-246247, it is necessary that the pressed portion does not interfere with the apparatus main body in the insertion process and that the pressing member can press the pressed portion even if the cartridge moves in the direction away from the pressing member in the positioning process. Therefore, it is necessary to provide the pressed portion at a position distant to some extent from the root of the protruding portion. Therefore, if the pressing member presses the pressed portion with the cartridge mounted, the protruding portion of the development container may be elastically deformed or creep-deformed when the pressed portion is pressed by the pressing member. Such a deformation of the protruding portion may possibly cause the loss of the amount of separation of the developing roller from the photosensitive drum when separating the developing roller from the photosensitive drum or the loss of the amount of contact pressure of the developing roller onto the photosensitive drum when bringing the developing roller into contact with the photosensitive drum.
When the pressing member is moved by a predetermined amount while pressing the pressed portion, the protruding portion of the development container is deformed and therefore the amount of separation of the developing roller from the photosensitive drum becomes smaller than the separation amount in a case where the development container is a rigid body. The loss of the separation amount refers to this amount of reduction in the separation amount. Therefore, to secure a predetermined separation amount, it has been necessary to increase the moving amount of the pressing member for separating the developing roller from the photosensitive drum taking the loss of the separation amount into consideration.
When the pressing member is moved by a predetermined amount while pressing the pressed portion, the protruding portion of the development container is deformed and therefore the contact pressure for bringing the developing roller into contact with the photosensitive drum becomes smaller than the contact pressure in a case where the development container is a rigid body. The loss of the contact pressure refers to this amount of reduction in the contact pressure. Therefore, to secure a predetermined contact pressure, it has been necessary to increase the moving amount of the pressing member for bringing the developing roller into contact with the photosensitive drum taking the loss of the contact pressure into consideration.
To gain the moving amount of the pressing member required to ensure the predetermined separation amount or the predetermined contact pressure taking the above-described losses into consideration, a space which is large to some extent needs to be allocated to allow the pressing member to move in the apparatus main body. Therefore, it has been difficult to downsize the apparatus main body.
The present disclosure is directed to the provision of a configuration having a pressing member capable of pressing a portion of a development container which is hardly deformed when a developing roller is separated.
The present disclosure is also directed to the provision of the following image forming apparatus.
According to an aspect of the present disclosure, an image forming apparatus includes a mounting unit configured to mount a development unit including a developing member, a pressing member configured to press the development unit mounted on the mounting unit to separate the developing member from a photosensitive member or bring the developing member into contact with the photosensitive member, and an urging member configured to urge the pressing member. When mounting the development unit on the mounting unit, the development unit moves in a first direction from the pressing member toward the development unit, parallel to a direction in which the pressing member and the development unit are arranged side by side. The pressing member is movable in the first direction. The urging member urges the pressing member to move the pressing member in the first direction.
Further aspects of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
<Overall Schematic Configuration of Image Forming Apparatus>
The image forming apparatus 1 is a four-color full-color electrophotographic laser beam printer for forming a color image on a recording medium. The image forming apparatus 1 of cartridge mountable/removable type uses four different process cartridges (hereinafter referred to as cartridges) P. The process cartridges P include a first cartridge PY, a second cartridge PM, a third cartridge PC, and a fourth cartridge PK which are removably mounted on an image forming apparatus main body 1A.
The front side of the image forming apparatus 1 according to the exemplary embodiments refers to the side on which the front door 2 is disposed. The rear side or back side refers to the opposite side of the front side. The longitudinal direction refers to the direction directed from the back side toward the front side (forward direction) and the opposite direction (backward direction). The right and left refers to the respective right- and left-hand sides, when viewed from the front side of the image forming apparatus 1. The lateral direction refers to the direction directed from right to left (leftward direction) and the opposite direction (rightward direction). The image forming apparatus main body (hereinafter referred to as an apparatus main body) 1A refers to portions of the image forming apparatus 1 other than the cartridges P. In the descriptions of the present exemplary embodiment, the longitudinal direction (LD) of the cartridge P is the direction parallel to the direction of the rotational axis (axial direction) of an electrophotographic photosensitive drum (hereinafter referred to as a drum) 3 serving as a photosensitive member (image bearing member). With the cartridge P, the side to which a driving force is transmitted from the apparatus main body 1A in the longitudinal direction (LD) (the side on which the portion receiving the driving force from the apparatus main body 1A is disposed) is referred to as a drive side, and the opposite side of the drive side is referred to as a non-drive side.
A cartridge storage unit 1B for storing the cartridges P is disposed at the central portion in the apparatus main body 1A. The cartridge storage unit 1B is also a mounting unit for mounting the cartridges P after being inserted.
The cartridges P have a similar electrophotographic process mechanism, with different colors of the developing agent (hereinafter referred to as toner) and different filling amounts of toner. In the cartridge storage unit 1B, the cartridges P mounted at such positions that an image can be formed is provided with a rotational driving force transmitted from the apparatus main body 1A and supplied with biases including a charging bias and a development bias (not illustrated).
In a cartridge frame 40 of the cartridge P according to the present exemplary embodiment, a drum 3 and process units (a charging unit 4, a development unit 5, and a cleaning unit 6) for acting on the drum 3 are integrally assembled. A charging roller is used as the charging unit 4. A developing roller 45 which is a developing member is used as the development unit 5. In a state where the cartridge P is mounted on the apparatus main body 1A and positioned, the direction of the rotational axis (axial direction) of the developing roller 45 is parallel to the axial direction of the drum 3. A cleaning blade is used as the cleaning unit 6. At the lower portion of each cartridge P, a laser scanner 8 is disposed as an image information exposure unit for the drum 3.
A feeding unit 9 is disposed under the laser scanner 8. The feeding unit 9 includes a sheet supplying cassette 10 for stacking and storing recording materials (transfer materials or final recording media) S, a feed roller 11, a separation unit 12, and a registration roller pair 13.
An intermediate transfer unit 14 is disposed above the four cartridges P. The intermediate transfer unit 14 is a primary transfer member for superimposing the toner images formed on the drums 3 of the first, the second, the third, and the fourth cartridges PY, PM, PC, and PK onto an intermediate transfer belt (a first recording medium, hereinafter referred to as a transfer belt) 15. The intermediate transfer unit 14 includes a driving roller 16 and a tension roller 17 which are in parallel disposed on the right-hand side and the left-hand side. The flexible endless transfer belt 15 is stretched between the two rollers 16 and 17. The transfer belt 15 is disposed so as to be inclined with respect to the horizontal direction.
In the cartridge storage unit 1B, the upper surface of the drum 3 of the cartridge P mounted at such a position that an image can be formed is in contact with the undersurface of a belt portion of the transfer belt 15 on the lower running side. The contact portion is a primary transfer portion. Inside the transfer belt 15, primary transfer rollers 18 are disposed to face the respective drums 3. In a state where the belt portions of the transfer belt 15 on the lower running side are in contact with the upper surfaces of all of the drums 3, the transfer belt 15 is circularly driven by the driving roller 16 at the speed corresponding to the rotational speed of the drums 3 in the direction of the arrow V3. The primary transfer rollers 18 are applied with a predetermined primary transfer voltage at a predetermined control timing. The driving roller 16 is in contact with a secondary transfer roller 19 via the transfer belt 15. The contact portion between the secondary transfer roller 19 and the transfer belt 15 is a secondary transfer portion. The secondary transfer roller 19 is applied with a predetermined secondary transfer voltage at a predetermined control timing.
A fixing unit 20 and a discharge unit 21 are disposed at the upper portion on the right-hand side of the apparatus main body 1A. The upper surface of the apparatus main body 1A serves as a discharge tray 22.
The cartridges PY, PM, PC, and PK are mounted side by side in the arrangement direction AD. In this case, the rotational axes of the drums 3 of the respective cartridges P are disposed on a straight line drawn by a one-point chain line of
<Cartridge Configuration>
In the first cartridge PY, yellow (Y) toner is stored in the developer container, and a toner image of the Y color is formed on the surface of the drum 3. In the second cartridge PM, magenta (M) toner is stored in the developer container, and a toner image of the M color is formed on the surface of the drum 3. In the third cartridge PC, cyan C toner is stored in the developer container, and a toner image of the C color is formed on the surface of the drum 3. In the fourth cartridge PK, black (K) toner is stored in the developer container, and a toner image of the K color is formed on the surface of the drum 3.
<Methods for Replacing and Mounting Cartridge>
In the image forming apparatus according to the present exemplary embodiment, each cartridge P is replaced by front access, i.e., by opening a front door 2 serving as an opening/closing member of the apparatus main body 1A as illustrated in
As illustrated in
The front side plate 38 of the apparatus main body 1A is provided with the front door 2 as an opening/closing member which is movable between a close position at which the opening 24 is closed and an open position at which the opening 24 is open. A cartridge door for making it easier to mount the cartridge P is disposed between the front door 2 and the front side plate 38. The cartridge door 23 is opened and closed in association with the front door 2.
In the present exemplary embodiment, the front door 2 can take an open state where the opening 24 is open and a closed state where the opening 24 is closed, centering on a horizontal door rotational axis (a first rotational axis) 25 (refer to
A method for mounting and removing the cartridge P will be described below with reference to
In the cartridge storage unit 1B of the apparatus main body 1A (inside the image forming apparatus main body 1A), there are disposed a cartridge upper guide 30, a cartridge lower guide 31, and a developing guide 32 for guiding each of the first, the second, the third, and the fourth cartridges PY, PM, PC, and PK while being mounted and removed. When inserting the cartridge P into the cartridge storage unit 1B, the cartridge upper rib 43A and the cartridge lower rib 43B are inserted into (and pinched by) the cartridge upper guide 30 and the cartridge lower guide 31, respectively, disposed on the apparatus main body 1A (insertion process as the first process). The insertion direction ID that is the moving direction of the cartridge P when inserting the cartridge P into the cartridge storage unit 1B is parallel to the longitudinal direction (LD) of the cartridge P mounted on the apparatus main body 1A. Although the development unit 44 is configured to be rotatable centering on a developing rotation center 43C, the development unit 44 is inserted with a pressed portion 44A regulated by the developing guide 32. The pressed portion 44A is a portion downwardly protruding from a main body 44B of the development unit 44. In this way, the developing guide 32 regulates the movement of the development unit 44 in the direction perpendicularly intersecting with the insertion direction ID thereof. In the present exemplary embodiment, the direction perpendicularly intersecting with the insertion direction ID is the arrangement direction AD. When the cartridge P has been inserted into the cartridge storage unit 1B, the cartridge upper rib 43A and the cartridge lower rib 43B are held by holding portions (not illustrated) of the apparatus main body 1A.
As illustrated in
As illustrated in
The pressing member 61 acts on the main stay 33 in association with the development unit 44 during the contact and separation operations of the cartridge P. Therefore, the pressing member 61 does not disturb the contact and separation operations. When the cartridge P has been inserted into the cartridge storage unit 1B, the pressed portion 44A and the developing guide 32 are set at different positions in the insertion direction ID. Therefore, the developing guide 32 does not disturb the contact and separation operations of the cartridge P (described below).
<Operation for Positioning Process Cartridge to Main Body>
A positioning operation after the cartridge P has been inserted into the apparatus main body 1A will be described below.
As described above, the cartridge door 23 is configured to rotate centering on the axis of a rail shaft 34 in association with the front door 2 (refer to
Where the cartridge P has been inserted into the apparatus main body 1A, the cartridge P is still in the non-positioning state. When the user closes the front door 2 in this state, the cartridge lower guide 31 (upwardly) moves in the positioning direction PD in association with the close operation of the front door 2. Then, the cartridge P enters the positioning state (positioning process as the second process). The cartridge lower guide 31 is provided with a front side pressurizing convex 57 and a rear side pressurizing convex 58 (refer to
The positioning direction (first direction) PD is a direction parallel to the direction in which the pressing member 61 and the development unit 44 are arranged from the pressing member 61 towards the development unit 44 (the direction in which the development unit 44 separates from the pressing member 61). In the present exemplary embodiment, the direction perpendicularly intersecting with the arrangement direction AD and the insertion direction ID is set as the positioning direction PD. The direction in which the pressed portion 44A protrudes from the main body 44B of the development unit 44 is the direction toward the pressing member 61 (an approximately opposite direction of the positioning direction PD), i.e., an approximately downward direction according to the present exemplary embodiment.
When the cartridge P moves in the positioning direction PD, the pressing member 61 rotates centering on the rotation center 62B since the pressing member 61 is urged toward the development unit 44 by the development urging spring 63. Therefore, with the movement of the development unit 44 of the cartridge P in the positioning direction PD, the second pressing surface 61A and the first pressing surface 61B of the pressing member 61 move in the positioning direction PD following the movement of the development unit 44 in the positioning direction PD. Therefore, when the cartridge P is in the positioning state, the pressing member 61 is in contact with the cartridge P.
<Contact and Separation Mechanism of Main Body and Operations>
The contact and separation mechanism provided in the apparatus main body 1A will be described below with reference to
The contact and separation mechanism mainly includes the pressing unit 60, a sliding member 51, a developing pressure spring 52, a separation lever 53, a separation cam 54, and a slide cap 56 which are all provided for each cartridge P. Therefore, the contact and separation mechanism corresponding to one cartridge P will be described below. The contact and separation mechanisms corresponding to other cartridges P have a similar configuration, and redundant descriptions thereof will be omitted.
As illustrated in
The contact and separation mechanism takes two different positions: a contact position for turning the cartridge P into the contact state and a separation position for turning the cartridge P into the separation state. The pressurizing operation of the pressing unit 60 will be described below with reference to
When changing the cartridge P from the contact state to the separation state, a first pressing surface (first pressing portion) 61B of the pressing member 60 presses the pressed portion 44A of the development unit 44 in the direction of the arrow F2 opposite to the direction of the arrow F1. Since the developing pressure spring 52 is provided in the apparatus main body 1A, the cartridge P is not subject to the force from the developing pressure spring 52 except for in the contact state. Therefore, the cartridge P is prevented from being creep-deformed by the force received from the developing pressure spring 52.
<Contact and Separation Operations of Cartridge>
The contact and separation operations of the cartridge P will be described in detail below with reference to
An operation for changing the process cartridge P from the separation state to the contact state will be described below with reference to
The separation state refers to a state where the developing roller 45 is separated from the drum 3 by a predetermined distance or more. The contact state refers to a state where the developing roller 45 is in pressure contact with the drum 3. The intermediate state refers to a state where the developing roller 45 is separated from the drum 3 by less than the predetermined distance. The cartridge P passes the intermediate state when shifting between the contact state and the separation state. When the cartridge P is in the contact state, toner borne on the surface of the developing roller 45 can be made adhere to the surface of the drum 3, and a latent image formed on the drum 3 can be developed with the toner.
In the separation states illustrated in
When a separation motor (not illustrated) is driven from the separation state, the separation cam 54 starts rotating in the direction of the arrow R1, as illustrated in
The pressing member 61 is constantly urged by the development urging spring 63 so that the pressing member 61 can follow the movement of the bottom surface of the development unit 44. Therefore, the second pressing surface 61A of the pressing member 61 can press a portion which is hardly deformed in the vicinity of the root of the pressed portion 44A of the development unit 44. Therefore, the configuration in which the second pressing surface 61A presses a portion in the vicinity of the root of the pressed portion 44A enables restricting the elastic deformation and temporal creep deformation of the pressed portion 44A pressed by the second pressing surface 61A, compared with the configuration in which the tip of the pressed portion 44A is pressed. Therefore, this configuration enables restricting the loss of the contact pressure of the developing roller 45 onto the photosensitive drum 3.
Operations for changing the cartridge P from the contact state to the separation state will be described below with reference to
When a motor (not illustrated) is driven from the contact state illustrated in
The pressing member 61 is constantly urged by the development urging spring 63 so that the pressing member 61 can follow the movement of the bottom surface of the development unit 44. Therefore, the first pressing surface 61B of the pressing member 61 can press a point which is hardly deformed in the vicinity of the root of the pressed portion 44A of the development unit 44. Therefore, the configuration in which the first pressing surface 61B presses a portion in the vicinity of the root of the pressed portion 44A enables restricting the elastic deformation and temporal creep deformation of the pressed portion 44A pressed by the first pressing surface 61B, compared with the configuration in which the tip of the pressed portion 44A is pressed. Therefore, this configuration enables restricting the loss of the amount of separation of the developing roller 45 from the photosensitive drum 3.
According to the present exemplary embodiment, when the cartridge P is in the positioning state, the development urging spring 63 urges the pressing member 61 to abut it against the bottom of the development unit 44, allowing the first pressing surface 61B and the second pressing surface 61A to press a portion that is hardly deformed in the vicinity of the root of the pressed portion 44A. However, when the cartridge P is in the positioning state, the development urging spring 63 does not necessarily need to abut the pressing member 61 against the bottom of the development unit 44. More specifically, when the cartridge P is in the positioning state, if the pressing member 61 is disposed more on the downstream side in the positioning direction PD than the pressing member 61 is when the cartridge P is in the non-positioning state, the pressing member 61 can press a portion closer to the root of the pressed portion 44A. This configuration enables restricting the loss of the contact pressure of the developing roller 45 onto the photosensitive drum 3 and the loss of the amount of separation of the developing roller 45 from the photosensitive drum 3.
According to the present exemplary embodiment, the two pressing units 61 are disposed in line in the insertion direction ID for each cartridge P, and the two pressing units 61 are connected with one sliding member 51. Naturally, three or more pressing units 61 may be disposed for each cartridge P. If the pressing unit 61 is configured so that the uniformity of the contact pressure and separation amount is unlikely to become uneven in the longitudinal direction of the developing roller 45, only one pressing unit 61 may be provided for each cartridge P. When two pressing units 61 are provided, two sliding members 51 corresponding to the two pressing units 61 may be provided instead of a configuration in which the two pressing units 61 are moved by one sliding member 51.
In the present exemplary embodiment, the cartridge P integrally mounts and removes the cleaning unit 43 and the development unit 44 on/from the apparatus main body 1A. However, the configuration of the cartridge P is not limited thereto. More specifically, the cartridge P may be configured so that only the development unit 44 can be removed from the apparatus main body 1A without removing the cleaning unit 43 from the apparatus main body 1A. For example, the development unit 44 is configured as a first cartridge P1 and the cleaning unit 43 is configured as a second cartridge P2, and the first cartridge P1 may be configured to be separately mounted on and removed from the apparatus main body 1A while leaving the second cartridge P2 in the apparatus main body 1A.
The pressed portion 44A may be pressed by the first pressing surface 61B during the process of inserting the cartridge P into the apparatus main body 1A (during execution of the first process). This enables preventing the developing roller 45 and the photosensitive drum 3 from coming into contact and interfering with each other and getting damaged in the insertion process, even without providing other regulation portions for regulating the position of the development unit 44.
In the above-described configuration, the pressing member 61 can press a portion that is hardly deformed in the vicinity of the root of the pressed portion 44A of the development unit 44 to bring the developing roller 45 into contact with the photosensitive drum 3 or separate the developing roller 45 from the photosensitive drum 3. This configuration enables restricting the deformation of the pressed portion 44 of the development container, enables restricting the loss of the contact pressure and the loss of the separation amount of the developing roller 45, and enables reducing the moving amount of the pressing member 61 and the size of the apparatus main body 1A.
According to the present exemplary embodiment, the pressing member 61 can press the cartridge P to separate the developing roller 45 from the drum 3 and press the cartridge P to bring the developing roller 45 into contact with the drum 3 by a predetermined pressure. Therefore, even if the cartridge P does not have an elastic member for bringing the developing roller 45 into contact with the drum 3, the developing roller 45 can be brought into contact with and separated from the drum 3. Naturally, the present exemplary embodiment is also applicable to a configuration in which the cartridge P has an elastic member for bringing the developing roller 45 into contact with the drum 3. In this case, the pressing force by the pressing member 61 can be obtained when bringing the developing roller 45 into contact with the drum 3. Therefore, it becomes possible to weaken the urging force of the elastic member compared with a configuration in which the developing roller 45 is brought into contact with the drum 3 only by the elastic member.
When inserting the development unit 44, the pressing member 61 can restrict the movement of the development unit 44 in the direction perpendicularly intersecting with the insertion direction ID to guide the insertion. This enables reducing the number of regulation members (guide members) dedicated for regulation (guidance), thus reducing the cost and size of the image forming apparatus. Particularly in a configuration in which the cleaning unit 43 and the development unit 44 can be separately removed from the apparatus main body 1A, it is necessary to regulate each of the cleaning unit 43 and the development unit 44. In this case, therefore, the present exemplary embodiment is more effective in reducing the cost and size of the image forming apparatus.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-048858 | Mar 2016 | JP | national |
| 2017-025410 | Feb 2017 | JP | national |
The present application is a Continuation of U.S. patent application Ser. No. 15/455,015, filed on Mar. 9, 2017, which claims priority from Japanese Patent Application No. 2016-048858 filed Mar. 11, 2016 and Japanese Patent Application No. 2017-025410 filed Feb. 14, 2017, all of which are hereby incorporated by reference herein in their entirety.
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| Number | Date | Country | |
|---|---|---|---|
| 20180348696 A1 | Dec 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15455015 | Mar 2017 | US |
| Child | 16058835 | US |
