This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2012-278858 filed Dec. 21, 2012.
(i) Technical Field
The present invention relates to transport devices and image forming apparatuses.
(ii) Related Art
An image forming apparatus, such as a copier or a printer, includes a transfer unit that transfers a toner image formed on a photosensitive member to a recording medium, and a fixing unit that fixes the toner image transferred to the recording medium. This image forming apparatus uses a transport device to transport the recording medium from the transfer unit to the fixing unit.
According to an aspect of the invention, there is provided a transport device including an endless belt having a recording-medium transport surface provided with multiple holes; stretching members between which the endless belt is stretched so as to be able to revolve; and a suction unit provided inside the endless belt. The suction unit has an opening having a larger width than the endless belt. The opening is exposed at both sides of the endless belt in the width direction. The suction unit draws air through the opening to cause the recording medium to stick to the endless belt.
Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
An exemplary embodiment of the present invention will be described below with reference to the drawings.
The image forming units 3K to 3Y form toner images of black (K), yellow (Y), magenta (M), and cyan (C). As illustrated in
The controller 2 includes a calculation device, such as a central processing unit (CPU), and a memory. The controller 2 controls the operation of components of the image forming apparatus 1.
The photosensitive member 10 (10K to 10C) is a cylindrical member having an image-bearing photosensitive layer formed of an organic photosensitive material. The photosensitive member 10 rotates in the direction indicated by the arrow in
The charging unit 20 (20K to 20C) applies a predetermined charging voltage to the surface of the photosensitive member 10 by using a charging roller rolling on the surface of the photosensitive member 10. The charging unit 20 may be of a contact charging type, which charges the photosensitive member 10 using a brush, or of a non-contact charging type, which charges the photosensitive member 10 by using corona discharge.
The exposure unit 30 (30K to 30C) irradiates the surface of the photosensitive member 10, charged by the charging unit 20, with light according to image data to form an electrostatic latent image having a latent image potential on the basis of the potential difference. This electrostatic latent image is moved to the position where the developing unit 40 is disposed, in accordance with the rotation of the photosensitive member 10.
The developing unit 40 (40K to 40C) includes a developing roller 41 (41K to 41C). Toner attracted to this developing roller 41 is transferred to the photosensitive member 10. In other words, due to the potential difference between the electrostatic latent image formed on the photosensitive member 10 and the charged toner, the toner moves to the surface of the photosensitive member 10. In this manner, the toner image is formed on the photosensitive member 10, and the toner image is moved to the position where the transfer unit 50 is disposed, in accordance with the rotation of the photosensitive member 10.
The transfer unit 50 includes an intermediate transfer belt 51, a back-up roller 52, support rollers 53, first transfer rollers 54 (54K to 54C), and a second transfer roller 55. A sheet P is transported by transport rollers 91 to the transfer unit 50, where a toner image on the intermediate transfer belt 51 is transferred to the sheet P. Then, this sheet P is transported to the fixing unit 70.
The intermediate transfer belt 51 is looped around the support rollers 53 and the back-up roller 52 and is driven by, for example, one of the support rollers 53. The first transfer rollers 54 are provided so as to face the corresponding photosensitive members 10 with the intermediate transfer belt 51 therebetween. The first transfer roller 54K faces the photosensitive member 10K, and the other transfer rollers face the corresponding photosensitive members.
The first transfer rollers 54K to 54C are rotated by the running intermediate transfer belt 51 and press the intermediate transfer belt 51 while they are rotated. The toner images formed on the photosensitive members 10K to 10C are transferred to the surface of the intermediate transfer belt 51 in an overlapping manner. The second transfer roller 55 is provided so as to face the back-up roller 52. The intermediate transfer belt 51 and the sheet P are nipped between the second transfer roller 55 and the back-up roller 52, and the toner image on the intermediate transfer belt 51 is transferred to the sheet P.
The transport device 60 transports the sheet P having the toner image transferred thereto in the transfer unit 50 to the fixing unit 70. The transport device 60 according to the exemplary embodiment will be described below.
The fixing unit 70 includes a fixing roller 71 having a heat source, and a pressure roller 72 provided so as to face the fixing roller 71. The fixing unit 70 applies heat and pressure to fix the unfixed toner image to the sheet P. The sheet P having the toner image fixed in the fixing unit 70 is transported by the transport rollers 91 and is then stored.
After the toner image is transferred to the sheet P, the cleaning unit 80 removes toner remaining on the surface of the photosensitive member 10. The sheet storage unit 81 accommodates multiple sheets P. A sheet P is picked from the sheet storage unit 81 by the sheet-feed roller 90 and is transported to the transfer unit 50 by the transport rollers 91.
Next, the transport device 60 according to the exemplary embodiment will be described.
The endless belts 61 convey the sheet P from the transfer unit 50 to the fixing unit 70. The endless belts 61 have multiple holes 61a in the transport surfaces 610 over which the sheet P is transferred. When the air A (not shown) is drawn through the holes 61a, the sheet P sticks to the transport surfaces 610 of the endless belts 61, enabling the sheet P to be stably transported.
As illustrated in
Corresponding to the four endless belts 61, four driving rollers 62 and four driven rollers 63 are provided. The endless belts 61 are looped around the driving rollers 62 and the driven rollers 63. The driving rollers 62 are driven by the driving unit 62a, such as a motor, causing the endless belts 61 to run in the sheet transport direction. The driven rollers 63 are rotated by the rotation of the endless belts 61.
As described above, the suction fan 65 is disposed inside the endless belts 61 to suck the air A. The suction fan 65 is provided, for example, at a side of the endless belts 61 arranged side-by-side and draws the air A from the inside of the endless belts 61 via the suction unit 64.
The suction unit 64 includes a lower part and an upper part that are made of, for example, sheet metal and resin, respectively. The driving rollers 62 and the driven rollers 63 are attached to the lower part, and the openings 65a are provided in the upper part.
The openings 65a are provided such that the sheet P sticks to the endless belts 61 via the multiple holes 61a. That is, the openings 65a are provided corresponding to the endless belts 61, such that the sheet P sticks to the endless belts 61 when the suction unit 64 draws the air.
Next, referring to
As illustrated in
The end width TH is, for example, from 5 mm to 10 mm. With this end width TH, even when the endless belts 61 meanders, the endless belts 61 do not touch portions of the suction unit 64 at the sides of the openings 65a.
Furthermore, the amount of air A drawn by the suction unit 64 to suck the sheet P is set according to the opening area of end areas TR, which are the exposed portions of the openings 65a, having the end width TH illustrated in
Next, the advantages of the transport device 60 according to the exemplary embodiment will be described using
As illustrated in
The transport device 60 and the image forming apparatus 1 having the same according to the exemplary embodiment have been described above. However, the present invention is not limited to the above-described exemplary embodiment, and other exemplary embodiments are also possible. The other exemplary embodiments will be described below.
Although the transport device according to the exemplary embodiment is formed of four endless belts, the configuration is not limited thereto. For example, in another exemplary embodiment, five endless belts may be used.
Although one transport device 60 is used in the exemplary embodiment, the configuration is not limited thereto. For example, in another exemplary embodiment, several transport devices 60 may be provided in the sheet transport direction.
Although the suction fan 65 is provided at a side of the endless belts 61 in the exemplary embodiment, the configuration is not limited thereto. For example, in another exemplary embodiment, the suction fan 65 may be provided below the endless belts 61.
Although the four endless belts 61 have the same end width TH in the exemplary embodiment, the configuration is not limited thereto. For example, in another exemplary embodiment, the end width TH may be increased in the middle of the transport device 60 in the width direction. Although the end width TH, which is the distance between the ends of the opening and the belt, of the transport device 60 according to the exemplary embodiment is from 5 mm to 10 mm, the configuration is not limited thereto. For example, in another exemplary embodiment, when the endless belts 61 run stably without meandering, the end width TH may be less than 5 mm, and when the distance between the endless belts 61 arranged side-by-side is large, the end width TH may be more than 10 mm.
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Number | Date | Country | Kind |
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2012-278858 | Dec 2012 | JP | national |