Patent Grant
9250605
This application is a National Phase application filed under 35 USC 371 of PCT International Application No. PCT/JP2013/051740 with an International Filing Date of Jan. 28, 2013, which claims under 35 U.S.C. ยง119(a) the benefit of Japanese Application No. 2012-038658, filed Feb. 24, 2012, the entire contents of which are incorporated herein by reference.
The present invention relates to a cartridge type process unit configured integrally with a plurality of maintenance components that include a photoreceptor drum and have a different life span, and to an image forming apparatus provided with such a unit.
In an electrophotographic image forming apparatus such as a digital copier and a printer, since image quality is remarkably affected, a photoreceptor drum is replaced periodically or as needed. However, mainly because the photoreceptor drum includes a hazardous substance, measures of taking care not to directly touch the photoreceptor drum at the time of the replacement, or preventing waste toner from a cleaning device from causing a surrounding area to be contaminated at the time of removal of the photoreceptor drum are required, so that the handling of the photoreceptor drum is difficult and the replacement of the photoreceptor drum has been performed at the time of maintenance by a serviceman.
Therefore, since the replacement operation of a photoreceptor drum always has to be performed by a serviceman on request, which causes inconvenience, in recent years, a device in which image forming portions such as a photoreceptor drum, and a cleaning device, a charger, and a developing device that are arranged around the photoreceptor drum are formed as a cartridge type process unit and integrally handled, which simplifies maintenance and enables the replacement of a photoreceptor drum to be easily performed not only by a serviceman but also by a user has been developed (see Patent Literature 1, for example). In such a process unit, when the photoreceptor drum reaches the end of a life span and a user performs the replacement of the photoreceptor drum, the entire process unit has been replaced and a used process unit has been discarded as it is.
Literature 1: Japanese Patent Laid-Open publication ho. H09-179473
However, such a replacement of an entire process unit, since still usable devices around the photoreceptor drum have to be also integrally replaced and discarded although the replacement of only a photoreceptor drum may be sufficient, has had problems such as an increase in running cost, an increase in waste amount as an industrial waste, and an adverse influence on the environment.
The cause of such problems lies in the fact that a photoreceptor dram, since being a maintenance component that requires to be handled with extreme care, is rigidly assembled to a unit frame body and a structure in which a photoreceptor drum alone can be easily attached and detached has not been adopted.
In view of the foregoing problems, an object of the present invention is to provide a process unit in which a photoreceptor drum can be simply handled and also can be easily attached and detached.
A process unit of the present invention is a cartridge type unit that is configured integrally with a plurality of maintenance components that have a different life span. In preferred embodiments of the present invention, the process unit has a photoreceptor drum, a frame body, a cleaning blade, a lock member, and a biasing member. The photoreceptor drum is one of the plurality of maintenance components. The photoreceptor drum has a first shaft portion projecting from a first end of the photoreceptor drum and a second shaft portion projecting from a second end of the photoreceptor drum. The frame body has: a mounting space in which the photoreceptor drum is mounted, the mounting space opening forward; a pair of first and second receiving portions opposed to each other in a longitudinal direction of the mounting space; and a hole that is provided in the first receiving portion and fitted over the first shaft portion at the first end of the photoreceptor drum so as to support the first shaft portion. The cleaning blade is arranged in the frame body and has a tip end portion projecting from a back side of the mounting space to an inside of the mounting space and contacting a surface of the photoreceptor drum with a pressing force. The lock member, facing a front side of the mounting space, is provided movably in the second receiving portion in an axial direction of the photoreceptor drum. The lock member rotatably supports the second shaft portion at the second end of the photoreceptor drum and locks the photoreceptor drum in a mounted state. The biasing member biases the lock member to the first end of the photoreceptor drum.
According to the configuration of the above-described process unit, when the photoreceptor drum is mounted on the frame body, the first shaft portion at the first end of the photoreceptor drum is kept fitted into a hole of the first receiving portion and the photoreceptor drum is moved from the front side of the mounting space to the inside of mounting space. The photoreceptor drum is temporarily supported by a repulsive force of the cleaning blade and positioned in a predetermined position in the mounting space. Then, in order to cause the lock member to support the second shaft portion at the second end of the photoreceptor drum, the lock member is retracted against a biasing force of the biasing member. Thereafter, the second shaft portion at the second end of the photoreceptor drum is supported by the lock member by a restoring force of the biasing member, so that the photoreceptor drum is locked in the mounted state. Thus, the photoreceptor drum is mounted on the frame body.
In addition, according to the configuration of the above-described, process unit, when the photoreceptor drum is removed from the frame body, the lock member is retracted against the biasing force of the biasing member so as to release the locking of the photoreceptor drum. The photoreceptor drum released from being looked is displaced in the axial direction in response to the restoring force of the biasing member and is surfaced toward the front side of the mounting space by the repulsive force of the cleaning blade. Then, while the second shaft portion at the second end of the photoreceptor drum is held, the first shaft portion at the first end is drawn out from the hole of the first receiving portion. Thus, the photoreceptor drum, is removed from the frame body.
It is to be noted on an end surface facing the mounting space of the lock member, a tapered surface that is inclined so as to expand the mounting space toward the front side of the mounting space may be formed. With this configuration, on the tapered surface of the lock member expanding toward the front side of the mounting space, the tip end of the second shaft portion at the second end of the photoreceptor drum is pressed toward the back side of the mounting space so as to be slid, and then a force against the biasing force of the biasing member is applied to the lock member, so that the lock member automatically moves in the direction in which the force is applied. Therefore, if is not necessary to operate the lock member by hand when the photoreceptor drum is mounted, which makes it possible to easily mount the photoreceptor drum.
It should be noted, if an auxiliary biasing member that presses and biases the cleaning blade on a surface of the photoreceptor drum is further provided, a pressing force applied to the photoreceptor drum by the cleaning blade can be increased by the auxiliary biasing member.
An example of the lock member may preferably include a ring shape member having a hole into which the second shaft portion at the second end of the photoreceptor drum is fitted. This makes it possible to support the entire perimeter of the second shaft portion by the hole of the lock member end to make the mounted state of the photoreceptor drum stable.
Another example of the lock member may preferably include a half ring shape member having a recessed portion with which the second shaft portion at the second end of the photoreceptor drum is engaged. Thus makes it possible to reduce the manufacturing cost of the lock member since the half of the material which forms the lock member is sufficient compared with the case in which the lock member has a ring shape.
According to preferred embodiments of the present invention, a process unit having a photoreceptor drum that can be simply handled and easily attached and detached can be provided.
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
As shown in
The image reading device 120 irradiates the image bearing side of the document with light and generates image data by sensing a right quantity of reflected light.
The image forming portion 110 is equipped with an intermediate transfer unit 40, image forming stations 30A, 30B, 30C, and 30D, a secondary transfer unit 50, an exposure unit 60, and a fixing unit 70.
The intermediate transfer unit 40 is equipped with an intermediate transfer belt 41 which is an endless belt, a first stretching roller 42, a second stretching roller 43, and a tension roller 44. The intermediate transfer belt 41 is stretched over the first stretching roller 42, the second stretching roller 43, and the tension roller 44. As an example, the first stretching roller 42 is a driving roller while the second stretching roller 13 is a driven roller. The tension roller 44 adjusts the tensile force of the intermediate transfer belt 41.
The image forming stations 30A to 30D perform an electrophotographic image forming process using toners of respective colors of black, cyan, magenta, and yellow. The image forming stations 30A to 30D are arranged side by side so as to be opposed to a predetermined region of the intermediate transfer belt 41. The image forming stations 30B to 30D are each configured in the same manner as the image forming station 30A.
The image forming station 30A is equipped with a monochrome image forming photoreceptor drum 31A that bears black toner. The image forming stations 30B, 30C, and 30D are equipped with color image forming photoreceptor drums 31B, 31C, and 31D that bear color toner, respectively. Each of the photoreceptor drums 31A to 31D forms an image bearing member.
The image forming station 30A includes a charging device 32A, a developing device 33A, a primary transfer roller 34A, and a cleaner device 35A that are disposed around the photoreceptor drum 31A. Similarly, the image forming stations 30B, 30C, and 30D include primary transfer rollers 34B, 34C, and 34D, respectively.
The image forming station 30A is equipped with a cartridge type process unit 1A in which the photoreceptor drum 31A, the charging device 32A, and the cleaner device 35A that are a plurality of maintenance components that have a different life span are formed, integrally. The image forming stations 30B, 30C, and 30D are also equipped with a similar process unit.
The photoreceptor drum 31A is rotated in a predetermined direction by a driving power transmitted from a not-shown driving source. The charging device 32A electrostatically charges the peripheral surface of the photoreceptor drum 31A to a predetermined potential.
The exposure unit 60 is configured to drive a semiconductor laser based on image data items corresponding to respective colors of black, cyan, magenta, and yellow to distribute laser light corresponding to the respective colors to each of the photoreceptor drums 31A to 31D of the image forming stations 30A to 30D. On the peripheral surfaces of the photoreceptor drums 31A to 31D, electrostatic latent images based on the image data items corresponding to the respective colors of black, cyan, magenta, and yellow are formed.
The developing device 33A is configured to supply black toner that is the color of the image forming station 30A, onto the peripheral surface of the photoreceptor drum 31A, thereby visualizing the electrostatic latent image into a toner image.
The intermediate transfer belt 41 has a surface that comes to face the photoreceptor drums 31A to 31D sequentially. The primary transfer roller 34A is arranged in a position opposed to the photoreceptor drum 31A across the intermediate transfer belt 41. The primary transfer roller 34B is arranged in a position opposed to the photoreceptor drum 31B across the intermediate transfer belt 41. The primary transfer roller 34C is arranged in a position opposed to the photoreceptor drum 31C across the intermediate transfer belt 41. The primary transfer roller 34D is arranged in a position opposed to the photoreceptor drum 31D across the intermediate transfer belt 41.
The primary transfer roller 34A, by being applied with a primary transfer bias of an opposite polarity (positive, for example) to the electrostatically charged polarity (negative, for example) of the toner, primarily transfers the toner image born on the photoreceptor drum 31A onto the surface of the intermediate transfer belt 41. The intermediate transfer unit 40 and the primary transfer rollers 34A to 34D are included in a transfer device 10.
Residual toner remaining on the surface of the photoreceptor drum 31A is removed by the cleaner device 35A. The cleaner device 35A, as will be described later, is equipped with a cleaning blade 351 having elasticity and a waste toner feeding screw 352. The cleaning blade 351 contacts the surface of the photoreceptor drum 31A and scrapes away the residual toner remaining on the surface. The waste toner feeding screw 352 is fed to one end side in the longitudinal direction of the frame body 400 in order to collect waste toners that have been scraped off by the cleaning blade 351.
During monochrome image formation, only the monochrome image forming station 30A performs the above described image forming process. Moreover, during full-color image formation, the image forming stations 30B to 30D in addition to the image forming station 30A perform the same process for the respective colors of cyan, magenta, and yellow, as does the image forming station 30A. The resulting toner images of the respective colors of black, cyan, magenta, and yellow, by the respective primary transfer rollers 34A to 34D of the image forming stations 30A to 30D applied with the primary transfer bias, are sequentially transferred onto the surface of the intermediate transfer belt 41 so as to be superimposed on one another to form one image.
The sheet supply portion 80 is provided with a sheet supply cassette 81, a manual supply tray 82, a main sheet feed path 83, and a subsidiary sheet feed path 84. In the sheet supply cassette 81, a plurality of sheets of paper of a size and kind with a relatively high frequency in use are stored. On the manual supply tray 82, a plurality of sheets of paper of a size and kind with a relatively low frequency in use are placed.
The main sheet feed, path 83 is formed to extend from the sheet supply cassette 81 and the manual supply tray 82 to a sheet discharge portion 90 by passing between the intermediate transfer belt 41 and the secondary transfer unit 50 and through the fixing unit 70. The subsidiary sheet feed path 84, which is a sheet feed path for double-sided printing, is formed in such a manner a sheet bearing an image formed on one side of a sheet of paper is turned upside down and then fed to between the intermediate transfer belt 41 and the second transfer unit 50 again.
The secondary transfer unit 50 has a secondary transfer roller 50A. The secondary transfer roller 50A, by being applied with a secondary transfer bias of an opposite polarity (positive, for example) to the electrostatically charged polarity (negative, for example) of the toner, transfers the toner image born on the surface of the intermediate transfer belt 41 onto a sheet of paper. The secondary transfer unit 50 is included in the transfer device 10.
The fixing unit 70, by heating and pressurizing the sheet of paper onto which the toner image has been transferred, fixes the toner image on the sheet of paper.
The sheet discharge portion 90 is equipped, with a sheet discharge tray 91 and a sheet discharge roller 92. The sheet, of paper on which the toner image has been fixed is discharged to the sheet discharge tray 91 by the sheet discharge roller 92. The sheet of paper is accommodated in the sheet discharge tray 91 with the side on which the toner image has been fixed facing downward.
Subsequently, a description is made of a configuration and operation of a characteristic process unit according to preferred embodiments of the present invention with reference to
As described above, as shown, in
As shown in
In addition, as shown in
The photoreceptor drum 31A includes a rotating shaft (not shown) that penetrates the drum, main body 311 and both drum flanges 312 and 313 and functions as a guide shaft that guides the photoreceptor drum 31A when the process unit 1A is inserted in the longitudinal direction and mounted on the main body of the image forming apparatus 100. At such a time, on the side of the first receiving portion 401 of the frame body 400, a drive connection member (not shown) is screwed and fastened on the shaft end surface of the rotating shaft (not shown), which makes one of the drum flanges 312 held and fixed between the shaft end surface of the rotating shaft (not shown) and the drive connection member (not shown), so that a driving force from a driving source (not shown) arranged on the side of the main body of the image forming apparatus 100 can be transmitted to the photoreceptor drum 31A through the drive connection member (not shown).
On the top portion of the periphery surface of the lock member 500, as an example, a rectangular operating portion 503 is raised and integrally formed. The operating portion 503 is a portion that is operated by hooking a finger when the lock member 500 is retracted. The end surface of the lock member 500 may include a tapered surface 502 that is inclined so as to expand the mounting space 410 toward the front side of the mounting space 410 (see
As shown, in
The second receiving portion 402 may be formed into a double cylindrical shape that is coaxially formed of an inner cylinder 403 and an outer cylinder 404. As shown in
As shown in
The lock member 500 is movable in the axial direction of the photoreceptor drum 31A from a position in which the inside of the end surface of the lock member 500 contacts the tip end surface of the inner cylinder 403 to a position in which the lock member 500 is restricted by a stopper 406 provided on the frame body 400. Positioning of the circumferential direction of the lock member 500 is performed by a partition wall 405 formed between the inner cylinder 403 and the outer cylinder 404 so as to prevent the rotation of the look member 500.
In addition, on the inside of the end surface of the lock member 500, a boss 304 is provided in a projecting manner. To the boss 504 is attached a compression coil spring 600 that is an example of the biasing member defined by the present invention. The compression coil spring 600 biases the lock member 500 to the first end of the photoreceptor drum 31A, and the lock member 500 is constantly biased to a position of being restricted by the stopper 406 within a movable range.
As shown in
The support member 353 is pivotally supported by the frame body 400 around a support point 3531 set at an end portion closer to the photoreceptor drum 31A in the short length direction, and an end portion farther from the photoreceptor drum 31A is biased upward with a tension coil spring 354. The tension coil spring 354 is an example of the auxiliary biasing member defined by the present invention. The tension coil spring 354 increases the pressing force applied to the photoreceptor drum 31A by the cleaning blade 351.
With reference to
To begin with, as shown in
The tip end portion of the cleaning blade 351 projects from the back side of the mounting space 410 to the inside of the mounting space 410. Therefore, as shown in
When the lock member 500 is pressed up to a position in which the second shaft portion 315 at the second end of the photoreceptor drum 31A is engaged with the recessed portion 501 of the lock portion 500, the lock portion 500 is moved like an arrow G shown in
It is to be noted while the recessed portion 501 is a semicircle and has only a circumferential length corresponding to an approximately half circumferential length of the second shaft portion 315, and, as shown in
Subsequently, a procedure when removing the photoreceptor drum 31A from the frame body 400 is described. In such a case, like an arrow J in
According to preferred embodiments of the present invention, it is possible to easily replace a photoreceptor drum that is a short-lived maintenance component of a process unit. In other words, even a person who is not an expert serviceman can safely and easily replace a photoreceptor drum and other long-lived maintenance components are effectively used, so that the reduction of running cost can be attained.
The foregoing preferred embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the following claims, not by the foregoing preferred embodiments. Further, the scope of the present invention is intended to include the scopes of the claims and all possible changes and modifications within the senses and scopes of equivalents.
1A Process unit
31A Photoreceptor drum
32A Charging device
35A Cleaner device
400 Frame body
500 Lock member
600 Compression coil spring (biasing member)
100 Image forming apparatus
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-038658 | Feb 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/051740 | 1/28/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/125300 | 8/29/2013 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6467965 | Wyer | Oct 2002 | B1 |
| 7272342 | Nagashima et al. | Sep 2007 | B2 |
| 20050128282 | Yamagata | Jun 2005 | A1 |
| 20080199213 | Saito et al. | Aug 2008 | A1 |
| 20100221041 | Takai et al. | Sep 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 09-179473 | Jul 1997 | JP |
| 2011-197531 | Oct 2011 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20150037066 A1 | Feb 2015 | US |
