Patent Application
20140291919
The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2013-072055, filed on Mar. 29, 2013. The contents of this application are incorporated herein by reference in their entirety.
The present disclosure relates to a recording medium feeding unit including a recording medium loading plate on which a sheet-like recording medium is loaded and positioning members that position the recording medium in the widthwise direction, and an image forming apparatus including the same.
Recording medium feeding units such as a stack tray (also designated as a manual feed tray) and a paper feed cassette are widely used. A recording medium feeding unit holds a pile of a plurality of sheet-like paper (recording media) for separating and feeding the paper one by one to an image forming section provided in the main body of an image forming apparatus in accordance with an image forming operation.
The configuration of a general stack tray will be described.
Paper is loaded on the paper loading plate 150. The main body 152 holds the paper loading plate 150. The pair of widthwise positioning members 151 position the paper in the widthwise direction perpendicular to a paper feeding direction. Each of the pair of racks 153 extends along the widthwise direction perpendicular to the paper feeding direction (that is, a paper conveyance direction or a direction illustrated with an arrow A). The pair of racks 153 are configured to move in the widthwise direction integrally with the widthwise positioning members 151. The pinion 154 is engaged with the pair of racks 153. The pinion 154 has, on its outer circumferential surface, a pinion gear (not shown) engaged with a rack gear 153a of each rack 153. Accordingly, the pinion 154 is rotated in association with the movement of the racks 153. As a result, when one of the widthwise positioning members 151 is moved, the pinion 154 is rotated, so as to move the other of the widthwise positioning members 151 in the opposite direction to the former widthwise positioning member 151 by the same distance.
If the pinion 154 has such a small rotation load that the widthwise positioning members 151 can be easily moved in the widthwise direction, paper is skewed (inclined) in feeding. In particular, the skew is easily caused in feeding thick paper. Therefore, in order to cope with the feed of thick paper, the rotation load of the pinion 154 is set to be large, in the stack tray 135, for restraining the movement of the widthwise positioning members 151.
Specifically, as illustrated in
Incidentally, in some paper feeding device, a paper loading section (corresponding to a paper loading plate) is elevated to secure a side fence (corresponding to the widthwise positioning member).
A recording medium feeding unit according to one aspect of the present disclosure includes a recoding medium loading plate, a main body, a pair of positioning members, a pair of racks, a pinion, a rotating shaft and an adjustment member. A recording medium is loaded on the recording medium loading plate. The main body holds the recording medium loading plate. The pair of positioning members position the recording medium in a widthwise direction perpendicular to a conveyance direction for the recording medium. The pair of racks are respectively provided on the pair of positioning members, extend along the widthwise direction and move in the widthwise direction integrally with the pair of positioning members. The pinion is rotatably provided on the main body, is engaged with each of the racks, and is rotated in association with the movement of the racks. The rotating shaft protrudes on the recording medium loading plate and is rotatably support the pinion. The adjustment member adjusts a rotation load of the pinion by allowing the pinion to be in contact therewith. The adjusting member is capable of adjusting the rotation load of the pinion in a manner to move in a thickness direction of the recording medium loading plate.
An image forming apparatus according to another aspect of the present disclosure includes the recording medium feeding unit of the aforementioned aspect and an image forming section. The image forming section forms an image on a recording medium fed from the recording medium feeding unit.
Now, one embodiment of the present disclosure will be described with reference to the accompanying drawings. It is noted that like reference numerals are used to refer to like or corresponding elements in these drawings to avoid redundant description.
Referring to
The image forming apparatus 1 includes an image forming section for forming an image on paper (corresponding to a recording medium) P fed from the stack tray 35. The image forming section includes photoconductive drums 11a to 11d, developing units 2a to 2d, an exposing unit 12, chargers 13a to 13d, cleaners 14a to 14d, primary transfer rollers 26a to 26d, an intermediate transfer belt 17 and a secondary transfer roller 34.
The photoconductive drums 11a, 11b, 11c and 11d are provided respectively correspondingly to colors of magenta, cyan, yellow and black. The developing units 2a to 2d, the exposing unit 12, the chargers 13a to 13d and the cleaners 14a to 14d are provided around and near the photoconductive drums 11a to 11d. Electrostatic latent images in accordance with image data are formed on the photoconductive drums 11a to 11d by the exposing unit 12 and the chargers 13a to 13d. The electrostatic latent images formed on the photoconductive drums 11a to 11d are developed into toner images respectively by the developing units 2a to 2d.
The endless intermediate transfer belt 17 is stretched around a tension roller 6, a drive roller 25 and a driven roller 27. The drive roller 25 is driven and rotated by a motor not shown. The intermediate transfer belt 17 is driven and rotated by the rotation of the drive roller 25.
The photoconductive drums 11a to 11d are provided below the intermediate transfer belt 17 to be in contact with the intermediate transfer belt 17 and to be adjacent to each other in a conveyance direction (illustrated with an arrow in
The primary transfer rollers 26a to 26d are in contact with the intermediate transfer belt 17 with a pressure to form primary transfer portions. In the primary transfer portions, the toner images respectively formed on the photoconductive drums 11a to 11d are successively transferred onto the intermediate transfer belt 17 at prescribed timing in association with the rotation of the intermediate transfer belt 17. As a result, a full color toner image is formed on the surface of the intermediate transfer belt 17 by overlapping the toner images of the four colors of magenta, cyan, yellow and black.
The secondary transfer roller 34 opposes the drive roller 25 with the intermediate transfer belt 17 sandwiched therebetween and is in contact with the intermediate transfer belt 17 with a pressure, thereby forming a secondary transfer portion. In the secondary transfer portion, the full color toner image formed on the surface of the intermediate transfer belt 17 is transferred to the paper P. After the transfer, a belt cleaning device 31 cleans the toner remaining on the intermediate transfer belt 17.
A paper feed cassette 32 for containing paper P is provided in a lower portion of the image forming apparatus 1. The stack tray 35 for supplying manually fed paper P is provided on the right hand side of the paper feed cassette 32. A first paper conveyance path 33 is provided on the left hand side of the paper feed cassette 32. The first paper conveyance path 33 conveys the paper P sent out from the paper feed cassette 32 to the secondary transfer portion of the intermediate transfer belt 17. Besides, a second paper conveyance path 36 is provided on the left hand side of the stack tray 35. The second paper conveyance path 36 conveys the paper P sent out from the stack tray 35 to the secondary transfer portion. Furthermore, a fixing section 18 and a third paper conveyance path 39 are provided in an upper left portion of the image forming apparatus 1. The fixing section 18 performs fixing processing on the paper P having an image formed thereon. The third paper conveyance path 39 conveys the paper P having been subjected to the fixing processing to a paper exit section 37.
The paper feed cassette 32 can be drawn outside (toward the surface side of
The first paper conveyance path 33 and the second paper conveyance path 36 meet before a registration roller pair 33c. The registration roller pair 33c conveys the paper P to the secondary transfer portion with timing of an image forming operation performed on the intermediate transfer belt 17 and a paper feeding operation. The full color toner image formed on the intermediate transfer belt 17 is secondarily transferred to the paper P, having been conveyed to the secondary transfer portion, by the secondary transfer roller 34 to which a bias potential is applied. In other words, the secondary transfer roller 34 transfers the image to the paper P having been fed from the paper feed cassette 32 or the stack tray 35. After the secondary transfer, the paper P is conveyed to the fixing section 18.
The fixing section 18 performs the fixing processing by heating and pressing the paper P to which the toner image has been transferred. Specifically, the fixing section 18 includes a fixing belt, a fixing roller, a pressure roller and the like. The fixing belt is heated by a heater. The fixing roller is in contact with the inner surface of the fixing belt. The pressure roller is provided to be in contact with the fixing roller with a pressure with the fixing belt sandwiched therebetween. After the fixing processing for the toner image performed by the fixing section 18, the paper P is turned over in a fourth paper conveyance path 40 if necessary. Then, a toner image is secondarily transferred by the secondary transfer roller 34 also on the rear surface of the paper P and then is fixed by the fixing section 18. The paper P having the toner image fixed thereon passes through the third paper conveyance path 39 to be exited to the paper exit section 37 by an exit roller pair 19.
Next, the configuration of the stack tray 35 will be described. In
As illustrated in
Paper P is loaded on the paper loading plate 50. The main body 52 holds the paper loading plate 50. The main body 52 includes a bottom plate 52a and a plurality of walls 52b standing in a peripheral portion of the bottom plate 52a. The main body 52 houses the racks 53 and the pinion 54. The paper loading plate 50 is attached to the main body 52 so as to cover the racks 53 and the pinion 54. The paper loading plate 50 includes a downstream loading plate 50a and an upstream loading plate 50b. The downstream loading plate 50a is provided downstream in the paper feeding direction. The upstream loading plate 50b is provided upstream in the paper feeding direction. The paper loading plate 50 has a paper loading surface (corresponding to a recording medium loading surface) 50c on which the paper P is loaded. The paper loading surface 50c has an opening 50d into which the adjustment pin 55 is inserted.
The pair of the widthwise positioning members 51 are provided on the paper loading plate 50 for positioning paper P in the widthwise direction perpendicular to the paper feeding direction. As illustrated in
The pinion 54 is rotatably provided on the main body 52. The pinion 54 is engaged with each of the racks 53. The pinion 54 has, on its outer circumferential surface, a pinion gear (not shown) formed to be engaged with rack gears 53a of the racks 53. Accordingly, the pinion 54 is rotated in association with the movement of the racks 53. As a result, when one of the widthwise positioning members 51 is moved, the pinion 54 is rotated, and the other of the widthwise positioning members 51 is moved in the opposite direction to the former widthwise positioning member 51 by the same distance.
The adjustment pin 55 adjusts the rotation load of the pinion 54. As illustrated in
Besides, a screw portion 52d having a threaded hole 52c is formed in the bottom plate 52a of the main body 52. The screw portion 52d in the present embodiment is a boss. The screw portion 52d protrudes 52 toward the paper loading plate 50 from the main body. The threaded hole 52c has a thread groove (not shown) to be engaged with the thread ridge of the shaft 55a. The shaft 55a of the adjustment pin 55 is fit in the threaded hole 52c of the screw portion 52d. The pinion 54 is sandwiched between the head 55b of the adjustment pin 55 and the screw portion 52d. The adjustment pin 5 rotatably attaches the pinion 54 to the screw portion 52d. Besides, the top surface of the head 55b of the adjustment pin 55 is exposed on the opening 50d of the paper loading plate 50. In addition, in the top surface of the head 55b, a groove (operating groove) 60 for catching a jig for rotating the shaft 55a (such as a coin or a flathead screwdriver) is formed. The groove 60 is in a shape of a linear grove in the present embodiment. Hereinafter, the groove 60 is designated as the linear groove 60.
The adjustment pin 55 applies the rotation load to the pinion 54 by allowing the pinion 54 to be in contact therewith. Specifically, by rotating the adjustment pin 55 around an axis extending in the thickness direction of the paper loading plate 50, the thread ridge formed in the shaft 55a of the adjustment pin 55 is engaged with a thread groove (not shown) formed on the inner surface of the screw portion 52d, so that the adjustment pin 55 can move in the thickness direction of the paper loading plate 50. Accordingly, the frictional resistance of the pinion 54 caused by the head 55b of the adjustment pin 55 and the screw portion 52d is changed. As a result, the rotation load of the pinion 54 is changed. In other words, the adjustment pin 55 is capable of adjusting the rotation load of the pinion 54 in a manner to move in the thickness direction of the paper loading plate 50.
In the present embodiment, for example, marks (scales) corresponding to the level of the rotation load of the pinion 54, such as “1” and “2”, are formed around the opening 50d of the paper loading surface 50c as illustrated in
If plain paper is to be fed, for example, the rotation load of the pinion 54 can be reduced by rotating the adjustment pin 55 to set the linear groove 60 of the adjustment pin 55 to face the mark “1”. As a result, the operability of the widthwise positioning members 51 can be improved. On the other hand, if thick paper is to be fed, for example, the rotation load of the pinion 54 can be increased by rotating the adjustment pin 55 to set the linear groove 60 to face the mark “2”. As a result, the skew of the thick paper can be suppressed by restraining the movement of the widthwise positioning members 51.
Incidentally, for regulating the rotation range of the adjustment pin 55, a regulation portion can be provided on the adjustment pin 55 and/or the paper loading plate 50.
As described with reference to
For example, if plain paper having a small load on the widthwise positioning members 51 in paper feeding is to be fed, the rotation load of the pinion 54 is reduced, so that degradation of the operability of the widthwise positioning members 51 can be suppressed. On the other hand, if thick paper is to be fed, for example, the rotation load of the pinion 54 can be increased to restrain the movement of the widthwise positioning members 51, so as to suppress the skew of the thick paper. In this manner, when the moving load of the widthwise positioning members 51 is adjusted by adjusting the rotation load of the pinion 54, satisfactory operability of the widthwise positioning members 51 and the effect to suppress the skew of paper P can be both attained.
Besides, as described above with reference to
Furthermore, the screw portion 52d having the threaded hole 52c for inserting the shaft 55a of the adjustment pin 55 is formed in the main body 52. The pinion 54 is rotatably supported on the cylindrical portion of the adjustment pin 55 and sandwiched between the seat surface of the head 55b of the adjustment pin 55 and the end surface of the screw portion 52d, and the rotation load of the pinion 54 is adjusted by the screw force of the adjustment pin 55. Accordingly, the rotation load of the pinion 54 can be easily adjusted by rotating the adjustment pin 55. Besides, the pinion 54 can be uniformly sandwiched by the head 55b of the adjustment pin 55 and the screw portion 52d along the peripheral direction of the pinion 54. As a result, unsymmetrical contact of the head 55b of the adjustment pin 55 to the pinion 54 can be suppressed.
Moreover, the linear groove 60 is formed on the top surface of the head 55b of the adjustment pin 55. Accordingly, the adjustment pin 55 can be easily rotated by using a coin or a flathead screwdriver.
As described with reference to
Incidentally, the embodiment described herein is intended to be illustrative and not restrictive. The scope of the present disclosure is defined not by the description of the embodiment but by the appended claims, and embraces all modifications as fall within the scope of the claims, together with all equivalents thereof.
For example, although the stack tray (manual feed tray) is described in the above embodiment as an example of the recording medium feeding unit of the present disclosure, the present disclosure is not limited to the stack tray. The present disclosure is applicable also to, for example, a paper feed cassette (corresponding to a recording medium feeding unit) attachable/detachable to/from the main body of an image forming apparatus and having a paper loading plate fluctuated in the vertical direction. Besides, the present disclosure is applicable also to a paper feeding unit (i.e., a recording medium feeding unit) for an automatic document feeder provided in an upper portion of the main body of an image forming apparatus for automatically feeding an original document to a document placing glass table to read an image.
Besides, the rotation load of the pinion is adjusted in two levels in the above-described embodiment, which does not limit the present disclosure, but the rotation load of the pinion can be adjusted in three or more levels. In such a case, the rotation load of the pinion can be suitably adjusted in accordance with three or more kinds of paper P (such as plain paper, a postcard, and thick paper thicker than a postcard).
Furthermore, although the adjustment pin is provided coaxially with the pinion in the above-described embodiment, the adjustment pin may not be provided coaxially with the pinion.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-072055 | Mar 2013 | JP | national |
