Patent Grant
10261463
The present disclosure generally relates to an image forming apparatus, such as a copying machine, a printer, and a facsimile machine, in which an exterior cover is opened and closed to remove and replace a process cartridge mounted inside the apparatus.
In a certain configuration of an image forming apparatus, an image bearing member (photosensitive drum) with a toner image formed thereon and an image forming unit (developing roller) are configured as a cartridge mountable on and removable from an image forming apparatus main body (apparatus main body) so that the replacement of consumables and other maintenance works can be easily performed.
In such cartridges, there is a contact development type in which development is performed by bringing the photosensitive drum into contact with the developing roller at the time of image formation. In a configuration discussed in Japanese Patent Application Laid-Open No. 2007-213025, to maintain a state where a photosensitive drum and a developing roller are in contact with each other, the developing roller is urged by an elastic member, disposed between a development unit and a drum unit of the cartridge respectively including the developing roller and the photosensitive drum, so that the developing roller comes into contact with the photosensitive drum. When the developing roller is separated from the photosensitive drum, the developing roller is moved to separate from the photosensitive drum by pressing the cartridge with a pressing member provided in the apparatus main body, and this state is maintained.
However, according to the configuration discussed in Japanese Patent Application Laid-Open No. 2007-213025 in which the developing roller is urged to come into contact with the photosensitive drum by the elastic member provided in the cartridge, it is necessary to provide an elastic member for generating an urging force in the cartridge. As a result, the size of the cartridge is increased. In a state where no cartridge is mounted on the apparatus main body, the developing roller is urged by the elastic member to come into contact with the photosensitive drum. Therefore, if this state is maintained for a long period of time, the frame of the cartridge, the developing roller, and the photosensitive drum may possibly be deformed. Therefore, in such a configuration, there is required a certain measure such as providing a member for restricting deformation in a state where no cartridge is mounted on the apparatus main body.
When the development unit and the drum unit are configured as different cartridges so that they can be separately mounted on and removed from the apparatus main body, it is basically difficult to provide an elastic member between the development unit and the drum unit.
The present disclosure generally relates to an image forming apparatus having a further advanced version of the above-described technique. More specifically, the present disclosure is directed to, even with a cartridge not having an elastic member for bringing a developing member (developing roller) into contact with a photosensitive member (photosensitive drum), the provision of a configuration for bringing the developing member into contact with the photosensitive member and separating the developing member from the photosensitive member.
According to an aspect of the present disclosure, an image forming apparatus includes a mounting unit configured to mount a cartridge including a developing member by moving the cartridge in an insertion direction, a pressing member having a first pressing portion configured to press the cartridge mounted on the mounting unit to separate the developing member from a photosensitive member and a second pressing portion configured to press the cartridge mounted on the mounting unit to bring the developing member into contact with the photosensitive member, the first and the second pressing portions integrally moving with a movement of the pressing member, and an elastic member configured to press the pressing member so that the second pressing portion presses the cartridge.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
<Overall 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 is of a cartridge mountable/removable type that 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 present exemplary embodiment 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 front-back 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 right and left, respectively, when viewed from the front side of the image forming apparatus 1. The right-left 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 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 driven side, and the opposite side of the drive side is referred to as a non-driven 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 by 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, each cartridge P mounted at an image formation position 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 each 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 parallelly disposed on the right-hand side and the left-hand side of the image forming apparatus 1. The flexible endless transfer belt 15 is stretched around 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 each cartridge P mounted at an image formation position 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 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. Each of 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 along the arrangement direction AD. In this case, the rotational axis of the drums 3 of the respective cartridges P are disposed on a straight line drawn by a dashed-dotted line illustrated in
<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 as an opening/closing member of the apparatus main body 1A as illustrated in
To take each cartridge P into the apparatus main body 1A and take the cartridge P out from inside of the apparatus main body 1A, the front side plate 38 of the apparatus main body 1A is provided with an opening 24 for allowing the passage of the cartridge P (an opening for mounting and removing the cartridge P). The direction of mounting and removing the cartridge P on/from the apparatus main body 1A is the axial direction of the drum 3.
The front side plate 38 of the apparatus main body 1A is provided with a 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 23 for allowing the cartridge P to be easily mounted on is disposed between the front door 2 and the front side plate 38. The cartridge door 23 is opened and closed interlocking 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, by rotating the front door 2 around 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 the cartridge P is inserted into the cartridge storage unit 1B, the cartridge upper rib 43A and the cartridge lower rib 43B are pinched by and inserted into the cartridge upper guide 30 and the cartridge lower guide 31 disposed on the apparatus main body 1A. The insertion direction ID as the moving direction of the cartridge P when the cartridge P is inserted 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 around a developing rotation center 43C, the development unit 44 is inserted with a pressed portion 44A regulated by the developing guide 32. 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.
The pressing member 50 operates on a main stay 33 interlocking with the development unit 44 during the contact and separation operations of the cartridge P. Therefore, the pressing member 50 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 around the axis of a rail shaft 34 interlocking with the front door 2 (refer to
After the cartridge P has been mounted on the apparatus main body 1A, when the user closes the front door 2, the cartridge lower guide 31 moves in the positioning direction PD (upward) interlocking with the close operation of the front door 2. The cartridge lower guide 31 is provided with a front side pressurizing portion 57 and a rear side pressurizing portion 58 (refer to
<Contact and Separation Mechanism and Operations of Main Body>
Next, the contact and separation mechanism provided in the apparatus main body 1A will be described with reference to
The contact and separation mechanism mainly includes the pressing member 50, a sliding member 51, a developing pressure spring 52, a separation lever 53, and a separation cam 54, 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 bringing the cartridge P into the contact state and a separation position for bringing the cartridge P into the separation state.
<Contact and Separation Operations of Cartridge>
The contact and separation operations of the cartridge P will be described in detail below with reference
First, an operation for changing the state of the process cartridge P from the separation state to the contact state will be described with reference to
In the separation states illustrated in
When a separation motor (not illustrated) is driven in the separation state, the separation cam 54 starts rotating in the direction of the arrow R1, as illustrated in
Next, operations for changing the cartridge P from the contact state to the separation state will be described with reference to
When a motor (not illustrated) is driven in the contact state illustrated in
As described above and as illustrated in
According to the present exemplary embodiment, the two pressing members 50 are disposed in line in the insertion direction ID for each cartridge P, and the two pressing members 50 are connected with one sliding member 51. Naturally, three or more pressing members 50 may be disposed for each cartridge P. If the pressing member 50 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 member 50 is provided for each cartridge P. When two pressing members 50 are provided, two sliding members 51 corresponding to the two pressing members 50 may be provided instead of a configuration in which the two pressing members 50 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 as a first cartridge P1 and the cleaning unit 43 as a second cartridge P2 can be separately mounted on and removed from the apparatus main body 1A.
According to the present exemplary embodiment, the pressing member 50 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 50 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. Since the urging force can be weakened in this way, it becomes possible to use a smaller-sized elastic member or a lower-price elastic member than that in conventional cases.
When the development unit 44 is inserted, the pressing member 50 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) as much as possible, and therefore, the cost and size of the image forming apparatus can be reduced. 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 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 disclosure 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 |
|---|---|---|---|
| 2016-048859 | Mar 2016 | JP | national |
| 2017-025411 | Feb 2017 | JP | national |
This application is a continuation, and claims the benefit, of U.S. patent application Ser. No. 15/453,570, presently pending and filed on Mar. 8, 2017, and claims the benefit of, and priority to, Japanese Patent Application No. 2016-048859, filed Mar. 11, 2016, and No. 2017-025411, filed Feb. 14, 2017, which are hereby incorporated by reference herein in their entireties.
| Number | Name | Date | Kind |
|---|---|---|---|
| 8238787 | Tani | Aug 2012 | B2 |
| 9389584 | Uchida | Jul 2016 | B2 |
| 20070071495 | Hashimoto | Mar 2007 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20180292781 A1 | Oct 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15453570 | Mar 2017 | US |
| Child | 16005462 | US |
