Patent Application
20110278792
This application claims priority under 35 U.S.C. 119 to Japanese Patent Application No. 2010-110409, filed on May 12, 2010, which application is hereby incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a paper transporting apparatus, a paper feeding unit including the paper transporting apparatus, and an image forming apparatus including the paper feeding unit.
2. Description of the Related Art
An image forming apparatus such as a printer, a facsimile device, and a copier, includes a paper feeding apparatus configured to feed paper from a paper feed cassette to an image forming unit. Such a paper feeding apparatus generally includes a pair of transport rollers arranged above the sides of the paper feed cassette, and paper in the paper feed cassette is transported to the image forming unit by the pair of transport rollers.
A paper feeding apparatus with a more specific configuration will be described. For example, an open-close cover which covers the pair of transport rollers is provided, and a roller shaft which supports one of the pair of transport rollers is attached to the open-close cover. Another roller shaft which supports the other of the pair of transport rollers is attached to a main body of the paper feeding apparatus. Since the transport rollers are separated from each other when the open-close cover is opened, paper jammed near the pair of transport rollers can be removed.
Paper feeding apparatuses with similar configurations to the one described above, which are added as an option, tend to cause paper jams near the transport rollers after several years of use. Research shows that a paper feeding apparatus included in an image forming apparatus placed under high temperature and humidity tends to cause paper jams.
Research done by the inventors of the present invention shows that the paper jam is caused by mechanisms described below. If the paper feeding apparatus experiences high temperature and humidity after a long period of use, a cover member such as the open-close cover made of resin may camber outward. The transport roller attached to the cover member is thus pulled outward following the camber of the cover member, thereby reducing the nip force between itself and the transport roller opposed thereto. Adequate transport force therefore cannot be generated or obtained. As a result, the chances of a paper jam increase.
In order to overcome the problems described above, preferred embodiments of the present invention provide a paper transporting apparatus which can maintain an adequate transport force at a pair of transport rollers, even if the cover member to which one of the pair of transport rollers is attached cambers. The present invention also provides a paper feeding unit including the paper transporting apparatus and an image forming apparatus including the paper feeding unit.
A paper transporting apparatus according to a preferred the present invention includes a pair of transport rollers, a first roller shaft, a second roller shaft, a cover member, and an urging member. The pair of transport rollers includes a first transport roller and a second transport roller opposed to the first transport roller, and transports paper. The first roller shaft is inserted through the first transport roller, and the second roller shaft is inserted through the second transport roller. The cover member can be opened and closed. The urging member is attached to an inner surface of the cover member, and supports the second roller shaft. The urging member urges the second roller shaft toward the first roller shaft when the cover member is closed.
In the paper transporting apparatus according to a preferred embodiment of the present invention, paper is transported by the first and the second transport rollers which are attached respectively to the first and the second roller shafts. The urging member attached to the inner surface of the cover member supports the second roller shaft, and urges the second roller shaft toward the first roller shaft when the cover member is closed. In other words, the second roller shaft, which is not directly attached to the cover member, is supported by the urging member attached to the cover member and is urged toward the first roller shaft. Consequently, even if the cover member cambers outward, separation of the second roller from the first roller following the camber of the cover member can be prevented, and the nip force from the first and the second transport rollers therefore can be maintained. As a result, adequate transport force from the pair of transport rollers can be maintained even if the cover member, to which one of the pair of transport rollers is attached, cambers.
The paper feeding unit according to a preferred embodiment of the present invention includes a storage unit and a paper transporting apparatus. The storage unit contains paper. The paper transporting apparatus transports paper from the storage unit. The paper transporting apparatus includes a pair of transport rollers, a first roller shaft, a second roller shaft, a cover member, and an urging member. The pair of transport rollers includes a first transport roller and a second transport roller opposed to the first transport roller, and transports paper. The first roller shaft is inserted through the first transport roller. The second roller shaft is inserted through the second transport roller. The cover member can be opened and closed. The urging member, attached to the inner surface of the cover member, supports the second roller shaft, and urges the second roller shaft towards the first roller shaft when the cover member is closed.
The paper feeding unit according to a preferred embodiment of the present invention maintains adequate transport force from the pair of transport rollers so as to transport paper from the storage unit even if the cover member, to which one of the pair of transport rollers is attached, cambers.
An image forming apparatus according to a preferred embodiment of the present invention includes an image forming unit, a storage unit, and a paper transporting apparatus. The image forming unit forms an image on paper. The storage unit contains paper. The paper transporting apparatus transports paper from the storage unit to the image forming unit. The paper transporting apparatus includes a pair of transport rollers, a first roller shaft, a second roller shaft, a cover member, and an urging member. The pair of transport rollers includes a first transport roller and a second transport roller opposed to the first transport roller, and transports the paper. The first roller shaft is inserted through the first transport roller. The second roller shaft is inserted through the second transport roller. The cover member can be opened and closed. The urging member attached to the inner surface of the cover member supports the second roller shaft, and urges the second roller shaft towards the first roller shaft when the cover member is closed.
The image forming apparatus according to various preferred embodiments of the present invention maintains adequate transport force from the pair of transport rollers so as to transport paper from the storage unit to the image forming unit even if the cover member, to which one of the pair of transport rollers is attached, cambers.
In the paper transporting apparatus, the paper feeding unit and the image forming apparatus according to a preferred embodiment of the present invention, it is preferable that the cover member has a substantially rectangular shape and includes a base end section that serves as an axis of rotation for opening and closing the cover member, and that the base end section of the urging member is attached to the side of the base end section of the cover member, and the head section of the urging member is located on the side of the head section of the cover member to support the second roller shaft and urge the second roller shaft towards the first roller shaft when the cover member is closed.
According to such a configuration of a preferred embodiment of the present invention, the base end section of the urging member is attached to the side of the base end section of the cover member, where relatively less camber occurs, and the head section of the urging member is located on the side of the head section of the cover member to support the second roller shaft and urge the second roller shaft towards the first roller shaft. Consequently, the base end section of the urging member is less affected by the camber of the head section of the cover member, where the camber occurs relatively frequently, thereby ensuring the state in which the second roller shaft is urged towards the first roller shaft.
In the paper transporting apparatus, the paper feeding unit and the image forming apparatus according to a preferred embodiment of the present invention, it is preferable that the urging member is a leaf spring. In that case, the second roller shaft can be urged with a relatively easy configuration.
In the paper transporting apparatus, the paper feeding unit, and the image forming apparatus according to various preferred embodiments the present invention, it is preferable that the cover member is made of resin. It is further preferable that the cover member is made of acrylonitrile butadiene styrene copolymer (ABS).
According to various preferred embodiments of the present invention, adequate transport force from the pair of transport rollers can be maintained even if the cover member, to which one of the pair of transport rollers is attached, cambers.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
Preferred embodiments of the present invention will be described with reference to the drawings. At first, a general configuration of a multifunction peripheral 1 according to a preferred embodiment of the image forming apparatus of the present invention will be described with reference to
The multifunction peripheral 1 preferably includes a print function which prints an image on paper, and also preferably functions as a copier, a scanner, and a facsimile device. The paper transporting apparatus 3 of the multifunction peripheral 1 is configured to maintain an adequate transport force from a driven roller 7 and a driving roller 6 opposed to the driven roller 7, even if an open-close cover 5 to which the driven roller 7 is attached cambers outward after several years of use.
As illustrated in
The image reading unit 9 includes a document tray 15 arranged at the top, and documents placed on the document tray 15 are passed through a reading position 19 and then ejected to a document eject tray 21 by an automatic document feeder (ADF) 17. In the ADF 17, the documents placed on the document tray 15 are picked up by a pick up roller 23, separated one by one by a separate pad 25, and then transported to a driving roller 27.
Two driven rollers 29, 31 are arranged on the driving roller 27, and each document is transported through a curved transport path along the periphery of the driving roller 27 to the reading position 19 arranged below the driving roller 27. The document is read by a reading apparatus 33 arranged below the reading position 19, and then ejected to the document eject tray 21 by a pair of eject rollers 35. When performing a copying process, document data read by the reading apparatus 33 is printed on paper by the image forming unit 13.
When performing a printing process, paper fed from the paper feeding section 11 is transported to the image forming unit 13 at a predetermined time after being registered by a pair of registration rollers 39. The image forming unit 13 forms an image on paper with an electrographic method. In order to do so, the image forming unit 13 includes a transferring unit 41 and a fixing unit 43, both of which are arranged along the transport path.
The transferring unit 41 includes a charged roller 47, an LED unit 49, a develop roller 51, and a transfer roller 53, all of which are arranged around a photoreceptor drum 45. In the transferring unit 41, an electrostatic latent image is formed on the photoreceptor drum 45 by the LED unit 49 after the photoreceptor drum 45 has been homogeneously charged by the charged roller 47.
Toner is transported from the develop roller 51, which contains the toner in a toner room 55, onto the electrostatic latent image on the photoreceptor drum 45, thereby forming a toner image on the photoreceptor drum 45. And then, the transported paper is nipped through the photoreceptor drum 45 and the transfer roller 53 with a voltage applied, thereby transferring the toner image on the photoreceptor drum 45 onto paper.
The fixing unit 43 includes a heat roller 57 and a press roller 59. By nipping the paper, on which the toner image has been transferred, with the heat roller 57 and the press roller 59, the paper on which the toner image has been formed is heated and pressured, thereby fixing the toner on the paper to complete the printing process. The paper on which the image has been printed is then ejected to the eject tray 63 by an eject roller 61.
The paper feeding section 11 includes a paper cassette 65 which contains paper, and a pair of paper feed rollers 67 that feed the paper from the paper cassette 65. The paper cassette 65 preferably has a substantially rectangular parallelepiped shape. A lifting board 73 is arranged in the paper cassette 65 and has an end portion near an end surface of the paper cassette 65. The end portion of the lifting board 73 is urged upward by a spring (not illustrated). Accordingly, paper placed on the lifting board 73 would be in a state in which an end of the paper is pressed against a pick up roller 75 arranged on the upper portion of the end surface of the paper cassette 65.
Accordingly, the paper in the paper cassette 65 is picked up on a transport path 71 through the rotation of the pick up roller 75. The picked up paper is then transported to the pair of registration rollers 39 by the pair of paper feed rollers 67. The pair of paper feed rollers 67 includes a driving roller 79 arranged on the side of the paper cassette 65, and a driven roller 81 opposed to the driving roller 79. The driven roller 81 is attached to an open-close cover 83 attached to the side of the main body of the multifunction peripheral 1.
The open-close cover 83 is attached to the main body of the multifunction peripheral 1 in a way that it may be opened and closed around an axis of a hinge pin 85, and the driven roller 81 is attached to the inner surface of the open-close cover 83 through a roller shaft. Accordingly, the driving roller 79 and the driven roller 81 are opposed to each other when the open-close cover 83 is closed so as to nip and transport the paper.
The paper feeding section 11 further includes a paper feeding unit 69 according to the present preferred embodiment of the present invention. The paper feeding unit 69 is an optional cassette which can be added as an option. The paper feeding unit 69 will be described with reference to
The paper feeding unit 69 is arranged under the paper cassette 65. While a single stage of the paper feeding unit 69 is preferably provided in the present preferred embodiment, a plurality of stages of the paper feeding unit 69 can be arranged. The paper feeding unit 69 includes a containing unit 87 arranged in a frame body 70 preferably having a substantially rectangular parallelepiped shape, and the paper transporting apparatus 3.
The containing unit 87 preferably has a substantially rectangular parallelepiped and has the same configuration as the paper cassette 65. That is, paper is placed on a lifting board 89 having an end portion near an end surface 92 of the containing unit 87. The end portion of the lifting board 89 is urged upward by a spring (not illustrated). Accordingly, the end of the paper placed on the lifting board 89 is pressed against a pick up roller 91 arranged on the upper part of the end surface 92 of the containing unit 87.
The paper transporting apparatus 3 is arranged on the side of the end surface 92 of the containing unit 87. The paper transporting apparatus 3 will be described with reference to
The pair of roller shafts 95 includes a driving roller shaft 951 and a driven roller shaft 952. The driving roller shaft 951 and the driven roller shaft 952 are arranged on the upper portion of the end surface 92 so as to be parallel or substantially parallel to the upper edge of the end surface 92.
The driving roller shaft 951, arranged more towards the side of the containing unit 87 than the driven roller shaft 952, is attached to the frame body 70 of the paper feeding unit 69. One end of the driving roller shaft 951 is connected to a motor 99 so that the driving roller shaft 951 rotates in response to the motor 99. The driven roller shaft 952 is attached to the open-close cover 5, which is arranged to cover the side of the end surface 92 of the containing unit 87, through the urging member 97. The above configuration may also be changed to one in which a gear fixed to the driving roller shaft 951 receives a driving force from the motor 99, thereby rotating the driving roller shaft 951 so as to rotate the driving roller 6.
The three pairs of the transport rollers 93 transport the paper picked up by the pick up roller 91 from the containing unit 87 to the image forming unit 13. Each pair of the transport rollers 93 includes the driving roller 6 and the driven roller 7 opposed to each other.
The driving roller 6 rotates in response to the motor 99 since the driving roller 6 is fixed to the driving roller shaft 951. The driven roller 7 is attached to the driven roller shaft 952. In other words, the driven roller 7 is attached to the open-close cover 5 through the driven roller shaft 952.
The driven roller 7, the driven roller shaft 952, and the urging member 97 are attached to the open-close cover 5, constituting a cover unit 4.
The open-close cover 5 preferably has a substantially rectangular shape. The longer sides of the open-close cover 5 are arranged to be parallel or substantially parallel to the driving roller shaft 951 and the driven roller shaft 952. The open-close cover 5 is attached to the frame body 70 through a hinge pin 501. Of the two longer sides of the open-close cover 5, the one at the lower portion is a base end section 503, which serves as an axis for opening and closing the open-close cover 5. The other longer side, which is at the upper portion, is a head section 505.
The driving roller 6 made of rubber and the driven roller 7 made of resin are opposed to each other when the open-close cover 5 is closed, so as to nip and transport paper. When the open-close cover 5 is open, the three pairs of driving roller 6 and the driven roller 7 are respectively separated so that the paper jammed near the transport rollers 93 can be removed.
The open-close cover 5 is preferably made of resin such as acrylonitrile butadiene styrene copolymer (ABS). In the open-close cover 5, a central portion of the head section 505 tends to curve outward after several years of use due to age deterioration, open-close operations, high temperature, humidity, and the like.
For this reason, the two urging members 97 are attached to the inner surface of the open-close cover 5 so as to urge the driven roller shaft 952 towards the side of the driving roller shaft 951.
The urging member 97 includes a first surface 971 and a second surface 972, both of which are formed as a rectangular sheet, and a level surface 973 which connects the first surface 971 and the second surface 972. The end portion of the first surface 971 is a base end section 974 to be attached to the open-close cover 5, and the first surface 971 includes a screw hole 975. A long hole 977, where a boss for positioning formed on the open-close cover 5 is inserted into, is arranged more towards the side of the head section 976 than the screw hole 975. The first surface 971 is attached to the side of the base end section 503 of the inner surface of the open-close cover 5 with a screw.
The level surface 973 is a surface which folds up from an end of the first surface 971 towards the head section 976 side in a substantially vertical direction. The level surface 973 increases the elasticity of the urging member 97.
As illustrated in
A center portion 978 of the three portions of the head section 976 is the widest portion, and the head of the center portion 978 is folded up in a substantially vertical direction. The side portions 979 project farther from the base end side than the position where the head of the center portion 978 is folded, and curve in a horseshoe shape. Accordingly, when viewing the urging member 97 from the side as illustrated in
As illustrated in
The driving roller 6 and the driven roller 7 are opposed to each other when the open-close cover 5 is closed. The angle 981 formed between the level surface 973 and the second surface 972 of the urging member 97 becomes smaller when the open-close cover 5 is closed, compared with that when the open-close cover 5 is open. The second surface 972 of the urging member 97 is bent when the open-close cover 5 is closed, resulting in the deformation of the urging member 97. As a result, the driven roller shaft 952 is pressed towards the driving roller shaft 951 by the head section 976 arranged to support the driven roller shaft 952.
In other words, the head section 976 that supports the driven roller shaft 952 urges the driven roller shaft 952 towards the driving roller shaft 951, thereby pressing the driven roller 7 to the driving roller 6. While the center portion of the head section 505 in the open-close cover 5 may camber outward, the driven roller 7 is pressed to the driving roller 6 by the urging member 97, thereby maintaining enough nip force to transport paper.
As illustrated in
As illustrated in
In the paper transporting apparatus 3 according to the preferred embodiment described above, the urging member 97 is preferably attached to the inner surface of the open-close cover 5. Further, the urging member 97 supports the driven roller shaft 952 and urges the driven roller shaft 952 towards the driving roller shaft 951 when the open-close cover 5 is closed. Accordingly, even if the open-close cover 5 cambers outward, departure of the driven roller from the driving roller due to the camber of the open-close cover 5 is reliably prevented, thereby maintaining the nip force from the driving roller 6 and the driven roller 7. Consequently, adequate transport force from the pair of transport rollers 93 can be maintained even if the open-close cover 5, to which the driven roller 7 constituting the pair of transport rollers 93 is attached, cambers.
Further, in the paper transporting apparatus 3, the base end section 974 of the urging member 97 is attached to the side of the base end section 503 of the open-close cover 5, where relatively less camber occurs. Furthermore, the head section 976 of the urging member 97 is located on the side of the head section 505 of the open-close cover 5, thereby supporting the driven roller shaft 952 and urging the driven roller shaft 952 towards the driving roller shaft 951. Accordingly, the base end section 974 of the urging member 97 is less affected by the camber of the head section of the open-close cover 5, where the camber occurs relatively frequently.
Since the paper feeding unit 69 according to the present preferred embodiment includes the paper transporting apparatus 3, adequate transport force from the pair of transport rollers 93 can be maintained even if the open-close cover 5, to which the driven roller 7 of the pair of transport rollers 93 is attached, cambers. As a result, this configuration can reduce occurrence of jams of papers, which are transported from the containing unit 87 to the image forming unit 13.
Since the multifunction peripheral 1 according to the present preferred embodiment includes the paper feeding unit 69, adequate transport force from the pair of transport rollers 93 can be maintained even if the open-close cover 5, to which the driven roller 7 of the pair of the transport rollers 93 is attached, cambers. As a result, this configuration can reduce occurrence of jams of papers, which are transported from the containing unit 87 to the image forming unit 13.
The configuration described above may be changed to one in which the urging member urges the driven roller shaft 952 towards the driving roller shaft 951 through forming a long hole in the ribs 506 of the open-close cover 5 and inserting the driven roller shaft 952 through the long hole. However, in this case, if the open-close cover 5 cambers significantly outward for some reason, the long hole would be shifted outward, and the driven roller shaft 952 inserted through the long hole would also be shifted outward. As a result, the nip force from the driving roller 6 and the driven roller 7 would be reduced.
On the other hand, in the paper transporting apparatus 3 according to the present preferred embodiment, the driven roller shaft 952 is supported by the urging member 97 and urged towards the driving roller shaft 951 so that the driven roller shaft 952 is not affected by the camber of the open-close cover 5, thereby maintaining the nip force.
While a preferred embodiment of the present invention has been described above, the present invention is not limited to this, and the above-described preferred embodiment may be modified in various manners. For example, while a case has been described in which the paper transporting apparatus 3 is preferably included in the paper feeding unit 69, which functions as an optional cassette, the present invention is not limited to this case. The case may be changed to one in which the paper transporting apparatus according to a preferred embodiment of the present invention is included in the multifunction peripheral 1 as an apparatus configured to transport paper from the paper cassette 65 of the multifunction peripheral 1.
In this case, the driving roller 79 and the driven roller 81 arranged near the paper cassette 65 correspond to the pair of transport rollers included in the paper transporting apparatus according to a preferred embodiment of the present invention, and the open-close cover 83 corresponds to the cover member included in the paper transporting apparatus according to a preferred embodiment of the present invention. The roller shaft which is inserted through the driving roller 79 is attached to the main body of the multifunction peripheral 1. Further, the urging member is attached to the open-close cover 83. The head section of the urging member supports the roller shaft of the driven roller 81, and urges the roller shaft of the driven roller 81 towards the roller shaft of the driving roller 79. As a result, adequate transport force from the driven roller 81 attached to the open-close cover 83 and the driving roller 79 opposed to the driven roller 81 can be maintained even if the open-close cover 83 cambers.
Furthermore, the case may be changed to one in which the paper transporting apparatus according to a preferred embodiment of the present invention is included in the multifunction peripheral 1 as an apparatus configured to transport paper to the reading position 19 in ADF 17. In this case, the driving roller 27 and the driven roller 29 correspond to the pair of transport rollers included in the paper transporting apparatus according to a preferred embodiment of the present invention, and the cover member 30 arranged above the driven roller 29 corresponds to the cover member included in the paper transporting apparatus according to a preferred embodiment of the present invention. The roller shaft inserted through the driving roller 27 is attached to the main body of the multifunction peripheral 1. The cover member 30 is arranged to be opened and closed, and includes the urging member attached on the inner surface thereof. The head section of the urging member supports the roller shaft of the driven roller 29, and urges the roller shaft of the driven roller 29 towards the roller shaft of the driving roller 27. As a result, adequate transport force from the driven roller 29 attached to the cover member 30 and the driving roller 27 opposed to the driven roller 29 can be maintained even if the cover member 30 cambers.
While the present invention has been described with respect to preferred embodiments thereof, it will be apparent to those skilled in the art that the disclosed invention may be modified in numerous ways and may assume many preferred embodiments other than those specifically set out and described above. Accordingly, the appended claims are intended to cover all modifications of the present invention that fall within the true spirit and scope of the present invention, thereby supporting the state in which the driven roller shaft 952 is more positively urged towards the driving roller shaft 951.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-110409 | May 2010 | JP | national |
