Patent Grant
9310762
The present invention relates to a process cartridge, and an image forming apparatus which employs a process cartridge.
Here, an “electrophotographic image forming apparatus” means an apparatus, such as an electrophotographic copying machine, an electrophotographic printer (laser beam printer, LED printer, etc.), or the like, which forms an image on recording medium, with the use of an electrophotographic image forming method.
A “process cartridge” means a cartridge in which an electrophotographic photosensitive drum, and one or more process means, that is, a charging means, and a developing means or a cleaning means, for processing the electrophotographic photosensitive drum, are integrally disposed so that they can be removably mountable in the main assembly of the image forming apparatus. More specifically, a process cartridge is a cartridge in which an electrophotographic photosensitive drum, and at least one among the abovementioned processing means, such as a developing means, a charging means, and a cleaning means, are integrally disposed. It also means a cartridge in which at least a developing means as a processing means, and an electrophotographic photosensitive drum, are integrally disposed so that they can be removably mountable in the main assembly of an electrophotographic image forming apparatus.
In the field of an electrophotographic image forming apparatus which employs one of the electrophotographic image formation processes, a process cartridge system has long been employed, according to which an electrophotographic photosensitive drum, and a single or plurality of processing means which act on the electrophotographic photosensitive drum, are integrally disposed in a cartridge to make it possible for them to be removably mountable in the main assembly of the image forming apparatus. Also according to this process cartridge system, an image forming apparatus can be maintained by a user himself, without relying on a service person, drastically improving the image forming apparatus in operability. Thus, a process cartridge system is widely in use in the field of image forming apparatus.
The image forming operation of an electrophotographic image forming apparatus is as follows: First, the electrophotographic photosensitive drum is exposed to a beam of light projected from a laser, an LED, an ordinary electric light, or the like, while being modulated with pictorial information, forming thereby an electrostatic latent image on the photosensitive drum. The electrostatic latent image is developed by the developing apparatus. Then, the developed image on the photosensitive drum is transferred onto recording medium; an image is formed on the recording medium.
As regards the structure for positioning the process cartridge in the main assembly of the image forming apparatus, the following structure is known. A supporting member for supporting the process cartridge is pushed into the main assembly of the apparatus. Then, the process cartridge is raised by the engagement between the cartridge side positioning portion and the main assembly side positioning portion. Thereafter, the process cartridge is separated from the supporting member. In this manner, the process cartridge is positioned to the main assembly without interference from the supporting member. (Japanese Laid-open Patent Application Hei 6-29998). It is desirable that the mounting and the mounting operation of the process cartridge relative to the main assembly of the apparatus is simple and easy.
The present invention is one of the further developments of the above described prior art.
Thus, the primary object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus in which when the process cartridge is mounted to the main assembly of the apparatus, a first cartridge side portion to be positioned and a second cartridge side portion to be positioned are less frictioned relative to a member or members of the main assembly.
It is another object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus in which when the process cartridge is mounted to the main assembly of the apparatus, a first cartridge side portion to be positioned and a second cartridge side portion to be positioned are less contacted to a member or members of the main assembly.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus in which the mounting operativity of the process cartridge relative to the main assembly of the apparatus is improved.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus in which the process cartridge can be mounted to the main assembly of the apparatus with the stability.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus in which the positioning accuracy of the process cartridge in the main assembly is improved.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus in which the positioning accuracy of the process cartridge in the main assembly is stably high.
According to an aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, wherein said apparatus includes a first main assembly side positioning portion, a second main assembly side positioning portion, a first main assembly side guide, a second main assembly side guide, a first main assembly side regulating portion, a second main assembly side regulating portion, an urging member for urging process cartridge to the main assembly side positioning portion by an urging force, said process cartridge comprising an electrophotographic photosensitive drum; process means actable on said electrophotographic photosensitive drum; a first cartridge side portion-to-be-guided to be guided by the first main assembly side guide when said process cartridge enters the main assembly along an axial direction of said electrophotographic photosensitive drum; a second cartridge side portion-to-be-guided to be guided by the second main assembly side guide when said process cartridge advances in the main assembly along the axial direction of the electrophotographic photosensitive drum in mounting it to the main assembly; a first cartridge side portion-to-be-regulated, provided at a leading side with respect to the advancing direction, for being regulated by the first main assembly side regulating portion in upward movement thereof when said process cartridge advancing in the main assembly while being guided by the first main assembly side guide and the second main assembly side guide is urged upwardly by the urging force of said urging member; a second cartridge side portion-to-be-regulated, provided at a trailing side with respect to the advancing direction, for being regulated by the first main assembly side regulating portion in upward movement thereof when said process cartridge advancing in the main assembly while being guided by the first main assembly side guide and the second main assembly side guide is urged upwardly by the urging force of said urging member; a first cartridge side portion to be positioned to be positioned at the first main assembly side positioning portion by the urging force of said urging member after said first cartridge side portion-to-be-regulated advancing in the main assembly while being regulated in the upward movement by said first main assembly side regulating portion passes the first main assembly side regulating portion; and a second cartridge side portion to be positioned to be positioned at the second main assembly side positioning portion by the urging force of said urging member after said second cartridge side portion-to-be-regulated advancing in the main assembly while being regulated in the upward movement by said second main assembly side regulating portion passes the second main assembly side regulating portion, wherein said process cartridge is mounted to the main assembly with said first cartridge side portion to be positioned at the first main assembly side positioning portion by the urging force of said urging member and with said second cartridge side portion to be positioned at the second main assembly side positioning portion by the urging force of said urging member.
According to the present invention, a process cartridge and an electrophotographic image forming apparatus in which when the process cartridge is mounted to the main assembly of the apparatus, a first cartridge side portion to be positioned and a second cartridge side portion to be positioned are less frictioned relative to a member or members of the main assembly, can be provided.
According to the present invention, a process cartridge and an electrophotographic image forming apparatus in which when the process cartridge is mounted to the main assembly of the apparatus, a first cartridge side portion to be positioned and a second cartridge side portion to be positioned are less contacted to a member or members of the main assembly, can be provided.
According to the present invention, a process cartridge and an electrophotographic image forming apparatus in which the mounting operativity of the process cartridge relative to the main assembly of the apparatus is improved, can be provided.
According to the present invention, a process cartridge and an electrophotographic image forming apparatus in which the process cartridge can be mounted to the main assembly of the apparatus with the stability, can be provided.
According to the present invention, a process cartridge and an electrophotographic image forming apparatus in which the positioning accuracy of the process cartridge in the main assembly is improved, can be provided.
According to the present invention, a process cartridge and an electrophotographic image forming apparatus in which the positioning accuracy of the process cartridge in the main assembly is stably high, can be provided.
Embodiment 1
Hereafter, the process cartridge (which hereafter will be referred to as “cartridge” and electrophotographic color image forming apparatus (which hereafter will be referred to as “image forming apparatus”) in the first of the preferred embodiments of the present invention will be described with reference to the appended drawings.
(General Structure of Image Forming Apparatus)
First, referring to
The electrophotographic photosensitive drum 1 (which hereafter may be referred to as “photosensitive drum”) is rotationally driven in the clockwise direction of the drawing, by a driving member (unshown). Each cartridge 7 also has the following processing means, which are disposed in the adjacencies of the peripheral surface of the photosensitive drum 1 in a manner to surround the photosensitive drum 1, in the order in which they will be listed next. They are a cleaning means 6 (6a-6d), which removes the developer (which hereafter may be referred to as “toner”) remaining on the peripheral surface of the photosensitive drum 1 after the transfer, a charge roller 2 (2a-2d) which uniformly charges the peripheral surface of the photosensitive drum 1, a scanner unit 3 which forms an electrostatic latent image on the peripheral surface of the photosensitive drum 1, by emitting a beam of laser light while modulating the beam of laser light with pictorial information, a development unit 4 (4a-4d) which develops the electrostatic latent image on the peripheral surface of the photosensitive drum 1 with the use of toner, and an intermediary transfer belt 5 onto which the four toner images on the photosensitive drums, one for one, which are different in color, are sequentially transferred. The photosensitive drum 1, cleaning member 6, charge roller 2, and development unit 4 are integrated in the form of a cartridge (process cartridge), that is, the cartridge 7, which is removably mountable in the main assembly 100a of the image forming apparatus 100 by a user.
The intermediary transfer belt 5 is stretched around a driver roller 10 and a tension roller 11, being thereby supported by them. The main assembly 100a of the image forming apparatus 100 is provided with first transfer rollers 12 (12a-12d), which are on the inward side of the loop which the intermediary transfer belt 5 forms. The first transfer rollers 12 are positioned so that they oppose the photosensitive drums 1 (1a-1d), one for one. To the transfer belt 5, transfer bias is applied from a bias applying means (unshown).
After the formation of a toner image on the photosensitive drum 1, the toner image is transferred onto the intermediary transfer belt 5. More specifically, four toner images are formed on the four photosensitive drums 1, one for one. Then, as the four photosensitive drums 1 are further rotated in the direction indicated by an arrow mark Q, and the intermediary transfer belt 5 is rotated in the direction indicated by an arrow mark R, the four toner images are sequentially transferred (first transfer) in layers onto the intermediary transfer belt 5, by the positive bias applied to the first transfer rollers 12. Then, the four layers of toner images on the intermediary transfer belt 5, which are different in color, are conveyed to a second transferring portion 15.
Meanwhile, in synchronism with the progression of the abovementioned image forming operation, a sheet S of recording medium is conveyed by a sheet conveying means made up of a sheet feeding-and-conveying apparatus 13, a pair of registration rollers 17, etc. The sheet feeding-and-conveying apparatus 13 has a sheet feeder cassette 24 in which multiple sheets S are storable, a sheet feeder roller 8 which conveys the sheet S, and a pair of sheet conveying rollers 16 which conveys further the sheet S after the feeding of the sheet S into the main assembly 100a of the image forming apparatus 100. The main assembly 100a is structured so that the sheet feeder cassette 24 can be pulled out of the main assembly 100a in the frontward direction of the main assembly 100a, in
After being fed into the main assembly 100a from the sheet feeding apparatus 13, the sheet S is conveyed to the second transfer portion 15 by the pair of registration rollers 17. In the second transfer portion 15, positive bias is applied to the second transfer roller 18, whereby the four toner image on the intermediary transfer belt 5, which are different in color, are transferred (second transfer) onto the sheet S as the sheet S is conveyed through the second transfer portion 15.
A fixing portion 14 as a fixing means is a portion of the image forming apparatus, which fixes the toner images on the sheet S by applying heat and pressure. A fixation belt 14a is cylindrical, and is guided by a belt guiding member (unshown) having a heat generating means, such as a heater, bonded to the belt guiding member. The fixation belt 14a and a pressure application roller 14b are kept pressed against with each other by the application of a preset amount of pressure thereto, forming thereby the fixation nip.
After the transfer of the toner images (unfixed toner images) onto the sheet S from the image forming portion, the sheet S is conveyed to the fixing portion 14, and then, is conveyed through the fixation nip between the fixation belt 14a and pressure application roller 14b in the fixing portion 14. As the sheet S is conveyed through the fixation nip, the sheet S and the toner images thereon are subjected to heat and pressure. As a result, the unfixed toner images on the sheet S become fixed to the sheet S. Thereafter, the sheet S having the fixed toner images is discharged into a delivery tray 20 by a pair of sheet discharging rollers 19.
Meanwhile, the toner remaining on the peripheral surface of the photosensitive drum 1 after the toner image transfer is removed by the cleaning member 6. Then, the removed toner is recovered into a chamber for the recovered toner, which is in the photosensitive member unit 26 (26a-26d).
As for the toner remaining on the intermediary transfer belt 5 after the transfer (second transfer) of the toner images onto the sheet S, it is removed by a transfer belt cleaning apparatus 23. The removed toner is recovered into a waste toner container (unshown) located in the rear portion of the image forming apparatus, through the waste toner passage (unshown).
(Cartridge)
Next, referring to
Each cartridge 7 is made up of a photosensitive member unit 26 and a development unit 4. The photosensitive member unit 26 is provided with the photosensitive drum 1, charge roller 2 (charging means), and cleaning member 6 (cleaning means). The development unit 4 has a development roller 25.
The photosensitive drum 1 is rotatably supported by the cleaning means frame 27 of the photosensitive member unit 26, with the interposition of a pair of bearings which will be described later. In an image forming operation, the photosensitive drum 1 is rotationally driven, by transmitting to the photosensitive member unit 26 the driving force from a motor (unshown). There are the charge roller 2 and cleaning member 6 in the adjacencies of the peripheral surface of the photosensitive drum 1 as described above. As the above described transfer residual toner is removed from the peripheral surface of the photosensitive drum 1 by the cleaning member 6, the removed toner falls into a chamber 27a for the removed toner. The cleaning means frame 27 is also provided with a pair of charge roller bearings 28, which are attached to the cleaning means frame 27 in such a manner that the charge roller bearings 28 are movable in the direction indicated by a double-headed arrow mark D, which connects the centers of the charge roller 2 and photosensitive drum 1. The shaft 2j of the charge roller 2 is rotatably supported by the charge roller bearings 28, and the bearings 28 are kept pressured toward the photosensitive drum 1 by a pair of charge roller pressing members 46.
The development unit 4 has the development roller 25 and a developing means frame 31. The development roller 25 rotates in contact with the photosensitive drum 1 in the direction indicated by the arrow mark B. The development roller 25 is rotatably supported by a developing means frame 31. More specifically, the development roller 25 is supported by a pair of bearing members 32 (32R and 32L) attached to the lengthwise ends of the developing means frame 31. The development unit 4 is provided with a toner supply roller 34 and a development blade 35. The toner supply roller 34 rotates in contact with the development roller 25 in the direction indicated by an arrow mark C. The development blade 35 is for regulating in thickness the toner layer on the peripheral surface of the development roller 25. Further, the development unit 4 has a toner conveying member 36 for conveying the toner in the toner storage portion 31a of the development unit 4 to the toner supply roller 34 while stirring the toner. The toner conveying member 36 is in the toner storage portion 31a.
The development unit 4 is connected to the photosensitive member unit 26. More specifically, a pair of pins 37 (37R and 37L) are put through, one for one, the holes 32Rb and 32Lb of the bearing members 32R and 32L, respectively, so that the development unit 4 is pivotally movable relative to the photosensitive member unit 26 about the pins 37 (37R and 37L). The development unit 4 is under the pressure from pressure application springs 38. Therefore, when the cartridge 7 is used for image formation in the main assembly of the image forming apparatus, the development unit 4 rotates about the pins 37 in the direction indicated by an arrow mark A, placing thereby the development roller 25 in contact with the photosensitive drum 1.
(Structure of Means for Mounting Cartridge into Main Assembly of Image Forming Apparatus)
Next, referring to
Referring to
Incidentally, the abovementioned projection 29 (first portion of cartridge 7, by which cartridge 7 is guided) is located at the top of the leading end of the cartridge 7, in terms of the direction in which the cartridge 7 is inserted into the main assembly 100a, whereas the tongue-like portion 30 (second portion of cartridge 7, by which cartridge 7 is guided) is on the bottom surface of the cartridge 7, and extends from the leading end to the trailing end.
Each cartridge 7 is also provided with a pair of cartridge positioning portions 40a and 50a (by which cartridge 7 is positioned relative to main assembly 100a), which are located at the leading and trailing ends of the cartridge 7, in terms of the abovementioned cartridge insertion direction. The operation to mount the cartridge 7 into the main assembly 100a concludes as the cartridge 7 becomes correctly positioned in the main assembly 100a. Incidentally, for the purpose of controlling the rotation of the cartridge 7, which occurs as driving force is transmitted to the cartridge 7, the leading end of the cartridge 7 is provided with a shaft 27b (
In terms of the direction in which the cartridge 7 advances as it is inserted into the main assembly 100a, the projection 29 (by which cartridge 7 is guided) of the cartridge 7 is located at the top of the leading end of the cartridge 7, as described above. The tongue-like portion 30 of the cartridge 7 is on the bottom surface of the cartridge 7, extending from the leading end of the cartridge 7 to the trailing end of the cartridge 7. Further, in terms of the direction perpendicular to the axial line of the photosensitive drum 1, the tongue-like portions 29 and 30 are on the same side of the photosensitive drum 1.
Therefore, it is ensured that the cartridge 7 reliably advances into the main assembly 100a.
As for the structural arrangement for correctly positioning the cartridge 7 in the main assembly 100a, it will be described later in detail.
(Structure for Correctly Positioning Cartridge, and Structure for Pressing Cartridge)
Next, referring to
The bearing 40 (first bearing which supports one of lengthwise ends of shaft of photosensitive drum 1) is the bearing on the rear side, that is, the leading end side in terms the direction in which the cartridge 7 is made to advance in the main assembly 100a when it is mounted into the main assembly 100a. It is provided with a cartridge positioning first portions 40a (40a1, 40a2), which are two portions of the top side of the peripheral surface of the bearing 40a. More specifically, the cartridge positioning first portion 40a (which is made up of portions 40a1 and 40a2) is for correctly positioning the leading end of the cartridge 7 relative to the main assembly 100a, in terms of the direction vertical to the abovementioned cartridge advancement direction. It is arcuate in cross section. Incidentally, in terms of the cartridge advancement direction, the bearing 40, that is, the bearing which will be at the deepest end of the cartridge bay, is located at the downstream end of the cartridge 7 (
Further, the abovementioned cartridge positioning portions 40a (40a1 and 40a2) is positioned so that it straddles the axial line I of the photosensitive drum 1 (
Further, the cartridge 7 is provided with a pushing member 40c, which is the first pushing member for moving the pressing member 83 into its retreat. With reference to the center of the cartridge 7, in terms of the horizontal direction perpendicular to the abovementioned cartridge advancement direction, the pushing portion 40c is located closer to the lengthwise end wall of the cartridge 7 than the pressure catching portion 40b. The pushing portion 40c is protruding downstream from the downstream end wall of the cartridge 7 in terms of the cartridge advancement direction, and its end portion is provided with a projection 40d which is projecting downward. More specifically, the projection 40d of the pushing portion 40c is tapered, providing thereby gently slanted surfaces 40e and 40f, that is, the slanted surfaces on the downstream and upstream sides, respectively, which are slanted so that their intersection is the peak of the projection 40d (projection 40d).
Further, the bearing 40, that is, the bearing on the rear side, is provided with a first contact portion 40h (cartridge movement regulating first portion of cartridge), which protrudes further upward than the cartridge positioning portion 40a. The first contact portion 40h is flat across the top surface (end surface), and is between one end of the cartridge positioning first portion 40a1 and the other end of the cartridge positioning second portion 40a2. That is, the first contact surface 40h is between the cartridge positioning first and second portions 40a1 and 40a2; the cartridge positioning first portion 40a1 is located next to one end of the first contact surface 40h, and the cartridge positioning second portion 40a2 is located next to the other end of the first contact surface 40h. Located on the upstream of the first contact surface 40h in terms of the cartridge mounting direction is a surface 40g, which is closer to the axial line of the photosensitive drum 1 than the top surface of the first contact surface 40h. Further, the bearing 40, that is, the bearing on the rear end, is provided with a contact surface 40i, which is the surface for correctly positioning the cartridge 7 in terms of the lengthwise direction of the cartridge 7. Incidentally, as the cartridge 7 is mounted into the main assembly 100a, the contact surface 40i comes into contact with the inward surface of the rear lateral panel of the main assembly 100a, ensuring that the cartridge 7 is correctly position in terms of the lengthwise direction of the cartridge 7.
Next, the bearing 50 (second bearing, that is, bearing which supports other end of photosensitive drum 1 in terms of direction parallel to axial line of photosensitive drum 1) will be described. The bearing 50 is the bearing on the front side, that is, the trailing side in terms of the abovementioned cartridge advancement direction. The bearing 50, that is, the bearing on the front side, is provided with cartridge positioning second portions 50a (50a1 and 50a2), which are two portions of the top side of the peripheral surface of the bearing 50. More specifically, the cartridge positioning second portions 50a (portions 50a1 and 50a2) are for correctly positioning the front end of the cartridge 7 relative to the main assembly 100a, in terms of the direction perpendicular to the abovementioned cartridge advancement direction. They are arcuate in cross section. The cartridge 7 is also provided with an upward pressure catching portion 50b, which catches the pressure applied to the cartridge 7 by an upwardly pulling member 93 (
As described above, the cartridge 7 has the first bearing 40, which supports one of the lengthwise end portions of the photosensitive drum 1 in terms of the direction parallel to the axial line of the photosensitive drum 1. The contact surface 40h and cartridge positioning first portions 40a (40a1 and 40a2) are portions of the peripheral surface of the first bearing 40. Further, the cartridge 7 has the second bearing 50 which supports the other lengthwise end of the photosensitive drum 1 in terms of the direction parallel to the axial line of the photosensitive drum 1. The contact portion 50h (contact surface) and cartridge positioning second portions 50a are portions of the peripheral surface of the second bearing 50.
Therefore, it is ensured that the cartridge 7 is precisely positioned relative to the main assembly 100a.
Incidentally, like the cartridge positioning portion 40a, that is, the cartridge positioning portion on the rear side, the cartridge positioning portion 50a has a cartridge positioning portion (cartridge positioning third portion 50a1), which is on one side of the axial line of the photosensitive drum 1, and a cartridge positioning portion (cartridge positioning fourth portion 50a2), which is on the other side of the axial line of the photosensitive drum 1. The cartridge positioning third portion 50a1 (positioning portion on leading end side) is on the opposite side of the abovementioned axial line I from the cartridge positioning fourth portion 50a2 (positioning portion on trailing end side) (
Incidentally, in this embodiment, the cartridge 7 is provided with the cartridge positioning third and fourth portions 50a1 a 50a2 as the cartridge positioning portions on the trailing end side. Therefore, it is ensured that the cartridge 7 is more reliably pressed upon the pressure catching portions 92a of the main assembly 100a. However, the number of the cartridge positioning portions which the trailing end of the cartridge 7 is provided may be only one, as long as it is properly positioned.
Further, the cartridge 7 is provided with a pushing member 50c, which is the second pushing member for moving the upwardly pulling member 93 into its retreat. With reference to the center of the cartridge 7, in terms of the direction which is horizontal and perpendicular to the abovementioned cartridge advancement direction, the pushing portion 50c is located closer to the lengthwise end wall of the cartridge 7 than the pressure catching portion 50b. The pushing portion 50c is protruding downstream from the main portion of the bearing 50 in terms of the cartridge advancement direction, and its end portion is provided with a projection 50d which is projecting downward. More specifically, the projection 50d is tapered, providing thereby gently slanted surfaces 50e and 50f, that is, the slanted surfaces on the downstream and upstream sides, respectively, which are slanted in such a manner that their intersection is the peak of the projection 50d (projection 50d). Further, the bearing 50, that is, the bearing on the front side, is provided with a second contact portion 50h (contact surface, which serves as cartridge movement regulating portion), which protrudes further upward than the cartridge positioning portion 50a. The second contact portion 50h is flat across the top surface (second contact surface), and is between one end of the cartridge positioning third portion 50a1 and the other end of the cartridge positioning fourth portion 50a2. That is, the second contact surface 50h is between the cartridge positioning third and fourth portions 50a1 and 50a2; the cartridge positioning third portion 50a1 is located next to one end of the second contact surface 50h, and the cartridge positioning fourth portion 50a2 is located next to the other end of the second contact surface 50h. Located on the upstream of the contact surface 50h in terms of the cartridge mounting direction is a surface 50g, which is closer to the axial line of the photosensitive drum 1 than the top surface of the first contact portion 50h.
Further, in terms of the direction perpendicular to the axial line of the photosensitive drum 1, the top surface (area of first contact) of the contact portion 40h is different in position from the cartridge positioning first portions 40a (40a1 and 40a2). Also in terms of the direction perpendicular to the axial line of the photosensitive drum 1, the top surface (area of second contact) is different in position from the cartridge positioning second portions 50a (50a1 and 50a2).
Further, in terms of the above-mentioned cartridge advancement direction, the top surface (area of first contact) of the first contact portion 40h is on the leading end side, and the top surface (area of second contact) of the second contact portion 50h is on the trailing end side.
Therefore, it is ensured that the cartridge 7 is precisely positioned relative to the main assembly 100a.
Further in terms of the direction perpendicular to the axial line of the photosensitive drum 1, the top surface of the contact surface 40h is between one end of the cartridge positioning portions 40a (40a1 and 40a2) and the other end of the cartridge positioning portions 40a (40a1 and 40a2). Also in terms of the direction perpendicular to the axial line of the photosensitive drum 1, the top surface (area of contact) of the second contact portion 50h is between one end of the cartridge positioning second portions 50a (50a1 and 50a2) and the other.
Therefore, it is ensured that the cartridge 7 is precisely positioned relative to the apparatus main assembly 100a.
Next, the structure of the cartridge positioning portion of the main assembly 100a, and the cartridge pressing mechanism of the main assembly 100a, will be described.
Referring to
The lateral plate 82 is provided with two cartridge catching portions 82a (82a1 and 82a2), that is, the first portions of the main assembly, which are for correctly positioning the cartridge 7 relative to the main assembly in terms of the direction perpendicular to the direction (advancement direction) in which the cartridge 7 is mounted. The lateral plate 82 is also provided with the pressing member 83, which is for pressing the cartridge 7 toward the cartridge catching portion 82a by being under the pressure applied thereto by the resiliency (elastic force) of a compression spring 85. This pressing member 83 functions as an upwardly pushing member which keeps the cartridge 7 pressed upward by being pressed upward by the pressure applied by the compression spring 85.
The pressing member 83 is located under the cartridge catching portion 82a. It is attached to the lateral plate 82. More specifically, a shaft 84 solidly fixed to the lateral plate 82, that is, the lateral plate on the rear side, of the main assembly, is put through the through hole 83a, the axial line of which coincides with the pivotal axis of the pressing member 83, so that the pressing member 83 is enabled to take the cartridge pressing position in which it keeps the cartridge 7 pressed on the cartridge catching portions 82a, position in its retreat in which it does not press on the cartridge 7, and the standby position in which it remains in the path of the cartridge 7.
Further, the pressing member 83 is provided with a cartridge pushing portion 83b, by which the pressing member 83 pushes the cartridge when the pressing member 83 is in the cartridge pressing position. The cartridge pushing portion 83b corresponds in position to the pressure catching portion 40b of the cartridge 7. The pressing member 83 is also provided with a pressure catching first portion 83c for moving the pressing member 83 into the retreat. The pressure catching first portion 83c corresponds in position to the pushing portion 40c of the cartridge 7. The pressure catching first portion 83c is provided with an upward projection 83d. The upward projection 83d is provided with gently slanted surfaces 83e and 83f, which are the upstream and downstream surfaces of the projection 83d, respectively, in terms of the cartridge mounting direction. The surfaces 83e and 83f are slanted so that the joint between the two surfaces is the peak of the projection 83d. Further, in terms of the direction perpendicular to the cartridge mounting direction, the pressure catching portion 83c is located further outward (in terms of the radium direction of hole 83a) from the axial line of the hole 83a than the cartridge pushing portion 83b. That is, in terms of the lengthwise direction of the pressing member 83, the abovementioned axial line of the hole 83a, cartridge pressing portion 83b, and pressure catching portion 83c, are positioned in the listed order.
The lateral plate 82 is provided with a cartridge movement regulating first portion 86 (cartridge movement regulating first portion of main assembly) which prevents the cartridge 7 from moving upward by the reactive force generated as the cartridge pushes the pressing member 83 into its retreat. The cartridge movement regulating first portion 86 is formed of resin, and is located between the two cartridge catching portions 82a (82a1 and 82a2) of the lateral plate 82.
Referring to
Further, the cartridge pulling member 93 is provided with a cartridge pulling portion 93b for pulling the cartridge upward when the cartridge pulling member 93 is in the cartridge pulling position. The cartridge pulling portion 93b corresponds in position to the cartridge pulling force catching portion 50b of the cartridge 7. The cartridge pulling member 93 is also provided with a cartridge catching second portion 93c for moving the cartridge pulling member 93 into its retreat. The cartridge catching second portion 93c corresponds in position to the pushing portion 50c of the cartridge 7. It is provided with an upward projection 93d, which has gently slanted surfaces 93e and 93f (
Further, in terms of the direction perpendicular to the cartridge mounting direction, the cartridge catching portion 93c is located further outward from the axial line of the hole 93a than the cartridge pulling portion 93b. That is, in terms of the lengthwise direction of the cartridge pulling member 93, the hole 93a, cartridge pulling portion 93b, and cartridge catching portion 93c are positioned in the listed order. Further, the lateral plate 92, that is, the frontal lateral plate of the main assembly, is provided a cartridge movement regulating second portion 96, which is for preventing the cartridge 7 from being moved upward by the reactive force which occurs as the cartridge pulling member 93 is pushed into its retreat. The cartridge movement regulating portion 96 is between the abovementioned two cartridge catching portions 92a (92a1 and 92a2).
Incidentally, in this embodiment, on the leading end side of the cartridge 7 in terms of the cartridge mounting direction, the pressure applying member 83 (pressing member, upwardly pushing member) is located below the cartridge catching portion 83a to press the cartridge upward from below to cause the cartridge 7 to bump into the cartridge catching portions 82a, whereas on the trailing side of the cartridge 7 in terms of the cartridge mounting direction, the cartridge pulling member 93 (cartridge pressing member) is positioned above the cartridge catching portions 92a to pull the cartridge 7 upward from above to cause the cartridge to bump into the cartridge catching portions 92a which are positioned above the cartridge. That is, as the cartridge 7 is moved into its image forming position in the main assembly 100a, the cartridge catching portion 82a (portion to be pressed) is pressed by the upward force from the cartridge pushing member 83. Thus, the cartridge positioning first and second portions 40a1 and 40a2 (cartridge positioning portions of cartridge, on leading end side) are correctly positioned by the cartridge catching portions 82a (cartridge positioning first portion of main assembly). Further, the upwardly pulling force catching portion 50b is pushed by the upwardly pulling force from the upwardly pulling member 93. Therefore, the cartridge positioning third and fourth portions 50a1 and 50a2 (cartridge positioning portions of cartridge, on trailing end side) are correctly positioned by the cartridge catching portions 92a (92a1 and 92a2) (cartridge positioning second portions of main assembly). Thus, the employment of this structural arrangement makes it possible to provide the lateral plate 92, that is, the frontal lateral plate of the main assembly, with the hole through which the cartridge 7 can be mounted into the cartridge bay 22. Therefore, the bearing 50, that is, one of the bearings in the adjacencies of the cartridge positioning portion, can be directly pressed. Therefore, the pressure applied to the bearing 50 remains stable. Therefore, the cartridge 7 is precisely positioned and remains precisely positioned. Therefore, the photosensitive drum 1 is precisely placed in contact with the intermediary transfer belt 5, and remains precisely in contact with the belt 5.
Incidentally, this embodiment is not intended to limit the present invention in structural arrangement. That is, the cartridge pressing member 83 and cartridge pulling member 93 may be positioned on the leading and trailing end sides, respectively, as elastically pressing members, in terms of the cartridge mounting direction, or vice versa. In either case, the above described effects can be obtained.
(Operation of Cartridge Pressing Mechanism During Mounting and Removal of Cartridge)
Next, referring to
(a) Leading End Side: Operations of Cartridge Pressing Mechanism During Mounting and Removal of Cartridge
The cartridge 7 is to be mounted in the direction indicated by the arrow mark F as described before. Referring to
More specifically, the pressing member 83 moves into the position in its retreat, in which its pressing portion 83b does not contact the pressure catching portion 40b of the cartridge 7, as shown in
Further, when the cartridge 7 is mounted, the cartridge 7 is subjected to upward force, that is, the reactive force generated as the pressing member 83 is pushed down into its retreat. However, the contacting surface 40h comes into contact with the cartridge movement regulating portion 86, that is, the cartridge contacting first portion of the main assembly. Therefore, the cartridge 7 is prevented from moving upward. Here, the cartridge movement regulating portion 86 of the main assembly and the main assembly contacting surface 40h are positioned so that they remain in contact with each other until immediately before the cartridge positioning portion 40a is correctly positioned by coming into contact with the cartridge catching portion 83. Therefore, while the cartridge 7 is mounted, more specifically, from the moment the cartridge 7 begins to receive the upward pressure from the pressing member 83 until immediately before the cartridge 7 is correctly positioned, the cartridge movement regulating portion 86, that is, the cartridge regulating portion of the main assembly, which is formed of resin, and the contacting surface 40h, slide on each other, and therefore, the cartridge positioning portion 40a does not rub against the cartridge catching portion 82a of the main assembly, which is formed of a thin sheet of steel or the like. Therefore, the problem that the cartridge positioning portion 40a is shaved by the cartridge catching portion 82a is prevented.
As the cartridge 7 is inserted even further, the cartridge catching portion 83c is disengaged from the pushing portion 40c, and therefore, the pressing member 83 gradually returns to its pressing position from the retreat. Then, the cartridge 7 is inserted far enough for the contacting surface 40i, which is for correctly positioning the cartridge 7 in terms of the lengthwise direction of the cartridge 7, to come into contact with the lateral plate 82, that is, the rear lateral plate of the main assembly, the pressing portion 83b comes into contact with the pressure catching portion 40b, as shown in
As described above, the cartridge pressing mechanism is structured so that the pressing member 83 can be in the standby position, pressing position, and retreat. More specifically, in terms of the top to bottom direction, the standby position, pressing position, and retreat are located in the listed order. Therefore, the pressing member 83 applies a sufficient amount of pressure to the cartridge 7.
When removing the cartridge 7 from the main assembly 100a, the cartridge mounting operation described above is to be carried out in reverse. The pressure which the cartridge 7 receives from the pressing member 83 is removed by the pushing portion 40c, which is more distant from the axial line of the hole 83a (rotational axis) than the pressure catching portion 40b, as it is during the mounting of the cartridge 7. Therefore, the amount of force necessary for the operation to remove the cartridge 7 in this embodiment is smaller than the amount of force necessary for the operation to remove a cartridge 7 in accordance with the prior art, as it is during the mounting of the cartridge 7.
Incidentally, whether mounting the cartridge 7 into the main assembly 100a, or removing the cartridge 7 from the main assembly 100a, it is necessary to move the pressing member 83 in the direction perpendicular to the cartridge mounting direction. In this embodiment, however, the projection 83d of the pressure catching portion 83c is provided with the gently slanted surfaces on the upstream and downstream sides, one for one, in terms of the cartridge mounting direction. Further, the projection 40d of the pushing portion 40c is provided with gently slanted surfaces on the upstream and downstream, one for one, in terms of the cartridge mounting direction. Further, when the cartridge 7 is mounted, the slanted surface 40e of the pushing portion 40c comes into contact with the slanted surface 83e of the pressure catching portion 83c, whereas when the cartridge 7 is removed, the slanted surface 40f of the pushing portion 40c comes into contact with the slanted surface 83f of the pressure catching portion 83c. The movement of the pressing member 83 in the direction of the arrow mark X begins under the above described condition. In other words, the cartridge pressing mechanism in this embodiment is structured so that the slanted surfaces of the cartridge 7 remain in contact with the slanted surfaces of the main assembly 100a while the pressing member 83 moves. Therefore, the cartridge 7 smoothly moves into the main assembly when the cartridge is mounted, and also, smoothly comes out of the main assembly when the cartridge 7 is removed.
(b) Trailing End Side: Operations of Cartridge Pressing Mechanism During Mounting and Removal of Cartridge
As the cartridge 7 is inserted, the slanted surface 50e of the pushing portion 50c of the bearing 50, that is, the front bearing of the cartridge 7, comes into contact with the slanted surface 93e of the cartridge catching portion 93c (standby position), as shown in
The pressure which the cartridge 7 receives from the upwardly pulling member 93 when it is mounted is removed by the pushing portion 50c, which is located further from the axial line of the hole 93a than the upward force catching portion 50b. That is, the amount of force necessary to push down the upwardly pulling member 93 against the force which acts to upwardly push the cartridge 7 is reduced by an amount equivalent to the ratio between the distance from the axial line of the hole 93a to the upward force catching portion 50b (upwardly pulling force applying portion 93b) and the distance from the axial line of the hole 93a to the pushing portion 50c (upwardly pulling member 93). Therefore, the amount of load to which the cartridge 7 is subjected when it is mounted is substantially smaller than the amount of pressure which the cartridge 7 receives from the upwardly pulling member 93; the amount of force required to mount the cartridge 7 is substantially smaller than the amount of force which the cartridge 7 receives from the upwardly pulling member 93.
Further, when the cartridge 7 is mounted, the cartridge 7 is subjected to upward force, that is, the reactive force generated as the upwardly pulling member 93 is pushed down into its retreat. However, the contacting surface 50h comes into contact with the cartridge movement regulating portion 96, that is, the cartridge contacting second portion of the main assembly. Therefore, the cartridge 7 is prevented from moving upward. Here, the cartridge movement regulating portion 96 of the main assembly and the main assembly contacting surface 50h are positioned so that they remain in contact with each other until immediately before the cartridge positioning portion 50a is correctly positioned by coming into contact with the cartridge catching portion 92a. Therefore, while the cartridge 7 is mounted, more specifically, from the moment the cartridge 7 begins to receive the upward force from the upwardly pulling member 93 until immediately before the cartridge 7 is correctly positioned, the cartridge movement regulating portion 96, that is, the cartridge regulating portion of the main assembly, which is formed of resin, and the cartridge contacting surface 50h, slide on each other, and therefore, the cartridge positioning portion 50a does not rub against the cartridge catching portion 92a of the main assembly, which is formed of a thin sheet of steel or the like. Therefore, the problem that the cartridge positioning portion 50a is shaved by the cartridge catching portion 92a is prevented.
As the cartridge 7 is inserted even further, the cartridge catching portion 93c is disengaged from the pushing portion 50c, and therefore, the upwardly pulling portion 93 gradually returns to the upwardly pulling position from the retreat. Then, the cartridge 7 is inserted far enough for the contacting surface 50i, which is for correctly positioning the cartridge 7 in terms of the lengthwise direction of the cartridge 7, to come into contact with the lateral plate 82, that is, the rear lateral plate of the main assembly, the upwardly pulling portion 93b comes into contact with the cartridge catching portion 50b, as shown in
As described above, the cartridge pressing mechanism is structured so that the upwardly pulling member 93 is enabled to move into the standby position, upwardly pulling (pressing) position, and retreat. More specifically, in terms of the top to bottom direction, the standby position, upwardly pulling (pressing) position, and retreat are located in the listed order. Therefore, the upwardly pulling member 93 applies to the cartridge 7 a sufficient amount of pressure for pulling up the cartridge 7.
When removing the cartridge 7 from the main assembly 100a, the cartridge mounting operation described above is to be carried out in reverse. The upward force which the cartridge 7 receives from the upwardly pulling member 93 is removed by the pushing portion 50c, which is more distant from the axial line of the hole 93a (rotational axis of pulling member 93) than the upward force catching portion 50b, as it is during the mounting of the cartridge 7. Therefore, the amount of force necessary for the operation to remove the cartridge 7 in this embodiment is significantly smaller than the amount of force necessary for the operation to remove a cartridge 7 in accordance with the prior art, as the amount of the force necessary for the operation to mount the cartridge 7 in this embodiment is significantly smaller than the amount of force necessary for the operation to mount a cartridge in accordance with the prior art.
Incidentally, whether mounting the cartridge 7 into the main assembly 100a, or removing the cartridge 7 from the main assembly 100a, it is necessary to move the upwardly pulling member 93 in the direction perpendicular to the cartridge mounting direction. In this embodiment, however, the projection 93d of the pressure catching portion 93c is provided with the gently slanted surfaces, which are on the upstream and downstream sides, one for one, in terms of the cartridge mounting direction. Further, the projection 50d of the pushing portion 50c is provided with gently slanted surfaces, which are on the upstream and downstream, one for one, in terms of the cartridge mounting direction. Thus, when the cartridge 7 is mounted, the slanted surface 50e of the pushing portion 50c comes into contact with the slanted surface 93e of the pressure catching portion 93c, whereas when the cartridge 7 is removed, the slanted surface 50f of the pushing portion 50c comes into contact with the slanted surface 93f of the pressure catching portion 93c. It is under this condition that the movement of the upwardly pulling member 93 in the direction of the arrow mark Y begins. In other words, the cartridge pressing mechanism in this embodiment is structured so that the slanted surfaces of the cartridge 7 remain in contact with the slanted surfaces of the main assembly 100a while the upwardly pulling member 93 moves. Therefore, the cartridge 7 smoothly moves into the main assembly when the cartridge is mounted, and also, smoothly comes out of the main assembly when the cartridge 7 is removed.
Incidentally, when the cartridge 7 is mounted or removed, the operation of the cartridge pressing mechanism in this embodiment occurs on the leading and trailing end sides, in terms of the cartridge mounting direction, roughly at the same time. Further, the direction in which the pressing member 83, that is, the rear pressing member, is rotated is opposite from the direction in which the pressing member 93 (upwardly pulling member), that is, the front pressing member, is rotated.
To describe in more detail, referring to
That is, the pressing member 83, which is on the rear side of the main assembly, is rotated in the direction indicated by an arrow mark M when it is moved into the retreat, whereas the upwardly pulling member 93, which is on the front side of the main assembly, is rotated in the direction indicated by an arrow mark N when it is moved into the retreat. Therefore, the loads from the pressing members 83 and 93, that is, the pressing members on the rear and front sides of the main assembly, to which the pushing portions 40c and 50c are subjected when the cartridge 7 is mounted or removed, act in the directions indicated by arrow marks P1 and P2, respectively, in
(Structural Arrangement for Preventing Shaving of Cartridge Positioning Portion of Cartridge)
The cartridge 7 in this embodiment is prevented from being shaved across its cartridge positioning portion when it is mounted into, or removed from, the main assembly 100a. This embodiment can reduce the problem that when the cartridge 7 is mounted into the main assembly 100a, the cartridge positioning first and second portions (portions 40a and 50a) of the cartridge 7 rub against the corresponding portions (members) of the main assembly 100a. Further, this embodiment can reduce the problem that when the cartridge 7 is mounted into the main assembly 100a, the abovementioned cartridge positioning first and second portions are placed in contact with the corresponding portions (members) of the main assembly 100a.
That is, as described above, the bearings 40 and 50, that is, the bearings on the leading and trailing end sides, in terms of the cartridge mounting direction, are provided with the contacting portions 40h and 50h, which protrude upward beyond the cartridge positioning portions 40a and 50a, which also are the portions of their peripheral surfaces. These contacting portions 40h and 50h are flat across the top surface, and positioned on one side of the cartridge positioning portion of the cartridge 7, and the other, respectively.
As the cartridge 7 is inserted into the main assembly 100a structured as described above, the cartridge 7 is subjected to the upward force, that is, the reactive force generated as the pressing member 83, that is, the cartridge pressing rear member, and the upwardly pulling member 93, that is, the cartridge pressing front member, are pushed downward into their retreats. During this process, the contacting portion 40h (surface) comes into contact with the cartridge movement regulating portion 86, that is, the cartridge contacting first portion of the main assembly, and the contacting portion 50h (surface) comes into contact with the cartridge movement regulating portion 96, that is, the cartridge contacting second portion of the main assembly. Therefore, the cartridge 7 is prevented from moving upward.
Here, the cartridge pressing mechanism is structured so that the cartridge movement regulating portion 86, that is, the cartridge movement regulating portion of the main assembly, which is on the rear side of the main assembly, and the contacting portion 40h (surface) remain in contact with each other until immediately before the cartridge positioning portion 40a is correctly positioned by coming into contact with the cartridge catching portion 82a. Similarly, the cartridge movement regulating portion 96, that is, the cartridge movement regulating portion of the main assembly, which is on the front side of the main assembly, and the contacting portion 50h (surface) remain in contact with each other until immediately before the cartridge positioning portion 50a is correctly positioned by coming into contact with the cartridge catching portion 92a.
Therefore, while the cartridge 7 is mounted, more specifically, from the moment the cartridge 7 begins to receive the upward force from the pressing member 83 and upwardly pulling member 93 until immediately before the cartridge 7 is correctly positioned, the cartridge movement regulating portions 86 and 96, that is, the cartridge regulating portions of the main assembly, which is formed of resin, and the cartridge contacting surfaces 40h and 50h, slide on the cartridge movement regulating portions 86 and 96, respectively, and therefore, the cartridge positioning portions 40a and 50a, which are on the rear and front sides, do not rub against the cartridge catching portions 82a and 92a of the main assembly, which are formed of a thin sheet of steel or the like. Therefore, the problem that the cartridge positioning portions 40a and 50a are shaved by the cartridge catching portions 82a and 92a is prevented.
As described above, the cartridge pressing mechanism is structured so that the cartridge 7 is mounted or removed while cancelling the cartridge pressing force by the pressure applied to the point of the pressing member, which is farther from the portion of the pressing member, by which the pressing member presses on the cartridge 7. Therefore, the amount of force necessary to mount or remove the cartridge 7 is sufficiently small relative to the amount of force (pressure) which the cartridge 7 receives from the pressing member. Thus, the amount of force required to mount the cartridge 7, that is, the cartridge in this embodiment, into the main assembly of the image forming apparatus in this embodiment, or remove the cartridge 7 from the image forming apparatus in this embodiment, is significantly smaller than that required to mount a cartridge in accordance with the prior art into the main assembly of an image forming apparatus in accordance with the prior art, or removing the cartridge in accordance with the prior art from the main assembly of the image forming apparatus in accordance with the prior art. In other words, the present invention can provide a cartridge and an image forming apparatus, which are significantly better in operability in terms of the mounting of the cartridge.
Further, when mounting the cartridge 7 into the main assembly 100a, or removing the cartridge 7 from the main assembly 100a, the cartridge positioning members are prevented from being shaved. Therefore, it is ensured that the cartridge 7 is correctly positioned.
Incidentally, the structure of the image forming apparatus in this embodiment is such that the cartridges are juxtaposed side by side (in parallel) in a horizontal straight row, and also, that the intermediary transfer unit is disposed on the top side of the cartridges so that the cartridges can be pressed upward from below by the pressing members. However, this embodiment is not intended to limit the present invention in terms of image forming apparatus structure. For example, the present invention is also applicable to an image forming apparatus structured so that its intermediary transfer unit is on the under side of the cartridges, and the cartridges are pressed downward from above by the pressing member (pressuring member). In the case of such a structural arrangement, the photosensitive drum 1 is placed in contact with the intermediary transfer belt 5 by applying downward pressure to the cartridge 7.
In the case of an image forming apparatus, such as the one in this embodiment, which is structured so that the cartridges are pressed from below, the amount of force necessary to press a cartridge to correctly position the cartridge needs to be set in consideration of the weight of the cartridge itself. Therefore, it must be greater than the amount of force necessary to press a cartridge in an image forming apparatus structured so that the cartridge is pressed from above, and so is the amount of force necessary to push down the pressing member. Thus, the effects of the present invention can be further enhanced by structuring the image forming apparatus so that the cartridge can be mounted or removed while cancelling the pressure applied to the cartridge by the cartridge pressing portion of the cartridge pressing member, by the portion of the cartridge pressing member, which is farther from the rotational axis of the cartridge pressing member than the cartridge pressing portion of the cartridge pressing member.
Also in this embodiment, it is on both the leading and trailing end sides of the cartridge, in terms of the cartridge mounting direction, that the force from the cartridge pressing member (inclusive of upwardly pulling member) is cancelled by the portion of the cartridge pressing member, which is farther from the axial line the pressing member than the cartridge pressing portion of the pressing member while the cartridge is mounted or removed. However, this embodiment is not intended to limit the present invention in scope in terms of the structure of an image forming apparatus. For example, an image forming apparatus may be structured so that only one end of the image forming apparatus, that is, either the leading or trailing end in terms of the cartridge mounting direction, is provided with the cartridge pressing member. However, an image forming apparatus having the pressing member on both the leading and trailing end in terms of the cartridge mounting direction is smaller in the total amount of force necessary to mount or remove the cartridge than an image forming apparatus having the cartridge pressing member on only the leading or trailing end in terms of the cartridge mounting direction. Also as described above, by structuring an image forming apparatus so that the cartridge pressing member on the rear side, and the cartridge pressing member (cartridge pulling member) on the front side, are symmetrical with respect to the direction in which the load from the pressing member is pushed up, it is possible to keep the cartridge 7 stable in attitude when mounting or removing the cartridge 7, enhancing further the effects of this embodiment of the present invention.
Embodiment 2
Next, referring to
The image forming apparatus in the first embodiment was structured so that the bearing of the cartridge 7, which is on the leading end, in terms of the direction in which the cartridge 7 is mounted into the main assembly of the image forming apparatus, is provided with the pressing member 83 having the pushing portion 83c for pushing down the cartridge 7. In this embodiment, the image forming apparatus structured so that the pushing portion for pushing down the pressing member is a part of the development unit, will be described.
Referring to
Referring to
Further, the pressing member 183 is provided with a pressing portion 183b, which presses on the cartridge 7 when the pressing member 183 is in the pressing position. The pressing portion 183b corresponds in position to the pressure catching portion 40b of the cartridge 7. The pressing member 183 is also provided with a pressure catching portion 183c, which is for moving the pressing member 183 into the retreat. The pressure catching portion 183c corresponds in position to the pushing portion 140c of the cartridge 7.
The pressure catching portion 183c is provided with an upward projection 183d, which has two surfaces 183e and 183f. The surfaces 183e and 183f are on the downstream and upstream sides, respectively, in terms of the cartridge mounting direction, and are gently slanted so that their intersection is the peak of the projection 183d.
In terms of the direction perpendicular to the cartridge mounting direction, the pressure catching portion 183c is on the opposite side of the pressing portion 183b from the axial line of the hole 183a. Further, the pressure catching portion 183c is located farther from the axial line of the hole 183a than the pressing portion 183b.
Next, the movement of the components of the cartridge pressing mechanism in this embodiment, which occur when the cartridge 7 is mounted into the image forming apparatus 100, will be described.
The cartridge 7 is mounted in the direction indicated by an arrow mark F shown in
Further, when the cartridge 7 is mounted, the cartridge 7 is subjected to upward force, that is, the reactive force generated as the pressing member 183 is pushed down into its retreat. However, the contacting surface 40h comes into contact with the cartridge movement regulating portion 86, that is, the cartridge contacting first portion of the main assembly. Therefore, the cartridge 7 is prevented from being moved upward. Here, the cartridge movement regulating portion 86 of the main assembly and the main assembly contacting second surface 40h of the cartridge 7 are positioned so that they remain in contact with each other until immediately before the cartridge positioning portion 40 (a pressure catching portion) is correctly positioned by coming into contact with the cartridge catching portion 82a. Therefore, while the cartridge 7 is mounted, more specifically, from the moment the cartridge 7 begins to receive the upward pressure from the pressing member 183 until immediately before the cartridge 7 is correctly positioned, the cartridge movement regulating portion 86, that is, the cartridge movement regulating portion of the main assembly, which is formed of resin, and the contacting surface 40h, slide on each other, and the pressure catching portion 40a (cartridge positioning portion of cartridge) does not rub against the cartridge catching portion 82a of the main assembly, which is formed of a thin sheet of steel or the like. Therefore, the problem that the cartridge positioning portion 40a is shaved by the cartridge catching portion 82a is prevented.
As the cartridge is inserted even further, the cartridge catching portion 183c is disengaged from the pushing portion 140c, and therefore, the pressing member 183 gradually returns to the pressing position from the retreat. Then, the cartridge 7 is inserted far enough for the contacting surface 40i, which is for correctly positioning the cartridge 7 in terms of the lengthwise direction of the cartridge 7, to come into contact with the lateral plate 82, that is, the rear lateral plate of the main assembly, the pressing portion 183b comes into contact with the pressure catching portion 40b, as shown in
Also in this embodiment, the pressing member 183 is enabled to apply a sufficient amount of pressure to the cartridge 7.
When removing the cartridge 7 from the main assembly 100a, the cartridge mounting operation described above is to be carried out in reverse. The upward force which the cartridge 7 receives from the pressing member 183 is cancelled by the pushing portion 140c, which is located farther from the axial line of the hole 183a, as it is during the mounting of the cartridge 7. Therefore, the amount of force necessary for the operation to remove the cartridge 7 in this embodiment is significantly smaller than the amount of force necessary for the operation to remove a cartridge 7 in accordance with the prior art, as the amount of the force necessary for the operation to mount the cartridge 7 in this embodiment is significantly smaller than the amount of force necessary for the operation to mount a cartridge in accordance with the prior art.
Further, as the cartridge catching portion 82a of the main assembly becomes disengaged from the pressure catching portion 40a (cartridge positioning portion of cartridge), the cartridge movement regulating portion 86 of the main assembly comes into contact with the second contacting surface 40h. Further, even during the removal of the cartridge 7, the cartridge movement regulating portion 86 of the main assembly, which is formed of resin, and the second contacting surface 40h, slide against each other, preventing thereby the pressure catching portion 40a from rubbing against the cartridge catching portion 82a of the lateral plate of the main assembly, as long as the cartridge 7 is under the upward force applied by the pressing member 183. Therefore, the problem that the pressure catching portion 40a (cartridge positioning portion of cartridge) is shaved by the cartridge catching portion 82a as it rubs against the cartridge catching portion 82a is prevented.
In this embodiment, only the portion of the development unit 4, which corresponds in position to the rear end side of the main assembly of the image forming apparatus, is provided with the pushing portion. However, it may be only the front end of the development unit that is provided with the pushing portion. The effects of providing only the front end of the development unit with the pushing portion are the same as that achievable by providing only the rear end of the development unit with the pushing portion.
While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.
This application claims priority from Japanese Patent Applications Nos. 331309/2006 filed Dec. 8, 2006, and 266399/2007 filed Oct. 12, 2007, which are hereby incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-331309 | Dec 2006 | JP | national |
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| Number | Date | Country | |
|---|---|---|---|
| 20140314445 A1 | Oct 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13920163 | Jun 2013 | US |
| Child | 14321113 | US | |
| Parent | 13414036 | Mar 2012 | US |
| Child | 13920163 | US | |
| Parent | 12716641 | Mar 2010 | US |
| Child | 13414036 | US | |
| Parent | 11925286 | Oct 2007 | US |
| Child | 12716641 | US |
