The present application claims priority under 35 U.S.C. ยง119 to Japanese Patent Application No. 2014-191084, filed on Sep. 19, 2014. The contents of this application are incorporated herein by reference in their entirety.
The present disclosure relates to an image forming apparatus including a fixing device.
A fixing device included in an electrographic image forming apparatus generally fixes a toner image to paper by melting the toner through application of heat and pressure to the paper. To do so, the fixing device includes a heat source such as a heater. When a conveyance path and a paper ejection section around the fixing device reach a high temperature due to radiant heat from the fixing device, toner fusing may be adversely affected.
In a situation in which paper is moist, vapor is generated from the paper heated by the fixing device and condenses in the conveyance path located downstream of the fixing device in a paper conveyance direction. As a result, succeeding paper may become wet due to the condensation and may become wrinkled as a result. In duplex printing, toner may not be transferred to a wet part of the paper re-conveyed to a transfer section, resulting in creation of an image void.
In view of the foregoing, a certain image forming apparatus includes a fan above the paper conveyance path that extends from the fixing section to the paper ejection section. Further, a duct is also provided that allows air to flow from the fixing section to the fan via the paper conveyance path and air to flow from a paper exit port to the fan via the paper conveyance path. In the above configuration, water vapor generated in fixing can be removed, thereby preventing paper from being wet by water drops condensed around the paper conveyance path.
Meanwhile, if paper having a high moisture content is heated by the fixing device, vapor may be generated as steam. When the steam is released outside the image forming apparatus, a user may mistake the steam for smoke. In view of the foregoing, a certain image forming apparatus has a configuration in which cool air is blown at a side of paper ejected from the paper ejecting section to cool the obverse and reverse surfaces of the paper. Thus, a situation in which steam is generated from ejected paper can be avoided.
An image forming apparatus according to the present disclosure includes an image forming section, a fixing device, a sheet conveyance path, a conveyance unit, a first cooling fan, a second cooling fan, and a conveyance guide member. The image forming section is configured to form a toner image on a sheet. The fixing device is disposed downstream of the image forming section in a sheet conveyance direction and configured to apply heat and pressure to the sheet to fix the toner image as unfixed yet to the sheet. The sheet conveyance path has first and second conveyance surface portions and guides the sheet to a sheet exit port after the sheet passes through the fixing device. The conveyance unit constitutes the first sheet conveyance surface portion and has an air introducing hole in communication with the sheet conveyance path. The first cooling fan is disposed within the conveyance unit and configured to suck air through the air introducing hole. The second cooling fan is disposed on an opposite side of the sheet conveyance path to the conveyance unit and configured to blow at the sheet passing air sucked from the sheet conveyance path. The conveyance guide member is fitted to the conveyance unit and configured to switch a conveyance direction of the sheet passing through the sheet conveyance path. The first cooling fan blows at the conveyance guide member air sucked from the air introducing hole.
An embodiment of the present disclosure will be described with reference to the accompanying drawings.
As illustrated in
In image formation, the charging unit 4 uniformly charges the photosensitive drum 5 as the photosensitive drum 5 rotates counterclockwise. The exposure unit 7 irradiates the photosensitive drum 5 with a laser beam based on image data to form an electrostatic latent image on the photosensitive drum 5. The developing unit 8 attaches toner to the electrostatic latent image to form a toner image. The toner is an example of a developer.
The toner container 9 supplies toner to the developing unit 8. Note that the image data may be transmitted from a personal computer (not illustrated), for example. The static eliminator (not illustrated) for removing residual charge on the surface of the photosensitive drum 5 is located downstream of the cleaning device 19.
Paper (a sheet of paper) is conveyed from a paper feed cassette 10 or a manual paper feeder 11 toward the photosensitive drum 5 on which the toner image is formed via a paper conveyance path 12 and a registration roller pair 13. The transfer roller 14 (an image transfer section) transfers the toner image formed on the surface of the photosensitive drum 5 to the paper. In this manner, the image forming section P forms the toner image on the paper. The paper to which the toner image is transferred is separated from the photosensitive drum 5 and conveyed to the fixing device 15.
The fixing device 15 is located downstream of the image forming section P in a paper conveyance direction (a sheet conveyance direction). The fixing device 15 applies heat and pressure to the paper to fix the toner image as unfixed yet on the paper.
A diverging guide 22 (a conveyance guide member) is disposed at a curved portion 20 of a paper conveyance path 16 (sheet conveyance path). The diverging guide 22 guides the paper to the paper conveyance path 16 once the paper has passed through the fixing device 15. A second paper ejection port 31 in communication with the curved portion 20 is located in a rear surface (a right surface in
Once the paper has passed through the fixing device 15 and a conveyance roller pair 23, the paper is conveyed onto the top of the image forming apparatus 100 through the paper conveyance path 16. In image formation on a single side of the paper (simplex printing), the paper is ejected onto an exit tray 18 from the first paper ejection port 30 via a conveyance roller pair 24 and a first ejection roller pair 17a. Alternatively, the paper is ejected from the second paper ejection port 31 via a second ejection roller pair 17b.
By contrast, in image formation on both sides of the paper (duplex printing), the conveyance roller pair 24 and the first ejection roller pair 17a are rotated in the reverse direction to reverse the paper conveyance direction after a tailing edge of the paper passes through the curved portion 20 of the paper conveyance path 16. As a result, the paper is distributed to a reverse conveyance path 21 diverging from the curved portion 20 and re-conveyed to the registration roller pair 13 in a state in which a side of the paper that has received the image is reversed. A toner image formed next on the photosensitive drum 5 is transferred by the transfer roller 14 to a side of the paper on which no image is formed. The paper to which the toner images are transferred is conveyed to the fixing device 15, subjected to fixing of the toner images, and then ejected onto the exit tray 18 from the first paper ejection port 30 via the conveyance roller pair 24 and the first ejection roller pair 17a. Alternatively, the paper is ejected from the second paper ejection port 31 via the second ejection roller pair 17b. That is, the paper conveyance path 16 guides the paper to the first or second paper ejection port 30 or 31 once the paper has passed through the fixing device 15. Note that the paper is reversed from the first side to the second side in the reverse conveyance path 21 and conveyed to the image forming section P, as described above. The second side of the paper is opposite to the first side thereof.
The image forming apparatus 100 includes a rear cover unit 40 (a conveyance unit). The rear cover unit 40 pivots about a pivot fulcrum 40a at the lower end part of the rear cover unit 40 and is openable and closable relative to the main body of the image forming apparatus 100. That is, the rear cover unit 40 is supported in an openable and closable manner on the rear surface of the main body of the image forming apparatus 100. The diverging guide 22, one roller 24a of the conveyance roller pair 24, one roller 25a of a conveyance roller pair 25, and the second ejection roller pair 17b are supported on the rear cover unit 40. The rear cover unit 40 constitutes a paper conveyance surface portion 16a (a sheet conveyance surface portion, a first sheet conveyance surface portion) at one side (outer side) of the paper conveyance path 16.
As illustrated in
Moreover, a control section 90 is disposed in the interior of the image forming apparatus 100 to control respective operations of various elements including the image forming section P, the fixing device 15, the first cooling fans 50a and 50b, and the second cooling fan 51. The control section 90 may include a central processing unit (CPU), for example.
As illustrated in
As illustrated in
The roller 25a of the conveyance roller pair 25 is supported on the conveyance guide 41. Slit-like air introducing holes 41a are located in the conveyance guide 41 at each of two locations in a width direction (right and left directions in
As illustrated in
As illustrated in
The first cooling fan 50b is a sirocco fan having the same configuration as the first cooling fan 50a. As illustrated in
For example, the first cooling fans 50a and 50b are disposed asymmetrically in the rear cover unit 40 such that the respective blowing ports 53 face obliquely upward (in directions indicated by hatched arrows in
Note that the configurations of the first cooling fan 50b and the second cooling fan 51 are the same as that of the first cooling fan 50a illustrated in
As illustrated in
In the present embodiment, the first cooling fans 50a and 50b suck hot air and vapor released from the paper S through the air introducing holes 41a in the conveyance guide 41. The heat and vapor are then exhausted toward the reverse surface of the diverging guide 22. On the other hand, the second cooling fan 51 (see
The first cooling fans 50a and 50b suck air heated by the paper S and discharge the hot air toward the reverse surface of the diverging guide 22. The diverging guide 22 is accordingly heated. As a result, a situation in which the vapor condenses into water drops on the diverging guide 22 and the paper conveyance path 16 to generate water drops can be avoided.
Moreover, air suction by the first cooling fans 50a and 50b through the air introducing holes 41a of the conveyance guide 41 allows conveyance of the paper S in a state in which the paper S is drawn toward the side of the conveyance guide 41 of the rear cover unit 40 (a side of the paper conveyance surface portion 16a). In the above configuration, the paper S can be conveyed stably in a state in which an opposite side (a second side) of the paper S to a print side S1 (a first side) of the paper S is close to the paper conveyance surface portion 16a. In other words, the paper conveyance surface portion 16a guides the opposite side to the print side S1 of the paper S. The print side S1 is a side of the paper S that is subjected to printing in simplex printing or that is subjected to printing first in duplex printing. The print side S1 of the paper S can be prevented from being abraded on the paper conveyance surface portion 16b constituting a part on the inner side (left side in
As illustrated in
At that time, in the same way as in simplex printing, the first cooling fans 50a and 50b suck air from the air introducing holes 41a in the conveyance guide 41 and the second cooling fan 51 (see
Here, in a situation in which the image forming apparatus 100 is used in a low temperature environment, for example, when the first cooling fans 50a and 50b or the second cooling fan 51 are/is operated in a state in which the inside of the image forming apparatus 100 is warmed insufficiently immediately after power-up or return from an energy saving (sleep) mode of the image forming apparatus 100, cool air is blown into the paper conveyance path 16 and at the diverging guide 22, which may induce condensation.
In view of the foregoing, after power-up or return from the energy saving mode of the image forming apparatus 100, the control section 90 (see
Note that the control section 90 may suspend the operations of at least one of the first cooling fans 50a and 50b and the second cooling fan 51 until paper printed first after power-up or return from the energy saving mode of the image forming apparatus 100 is ejected after the power-up or the return from the energy saving mode of the image forming apparatus 100.
As has been described so far, in the image forming apparatus 100 according to the present embodiment, condensation of vapor generated from paper around the fixing device 15 through fixing and release of the vapor outside the image forming apparatus 100 can be reduced effectively.
The present disclosure is not limited to the above embodiment. Various alterations can be made without departing from the gist of the present disclosure. For example, the first cooling fans 50a and 50b and the second cooling fan 51 are sirocco fans in the above embodiment. However, a propeller fan that sucks air in the rear cover unit 40 may be used instead of any of the sirocco fans. The same advantages as in the above embodiment can be obtained in this configuration. The respective locations and the respective numbers of first cooling fans 50a and 50b and second cooling fans 51 are not limited as above. Two or more second cooling fans 51 may be provided. One or three or more first cooling fans (the first cooling fans 50a and 50b) may be provided.
Number | Date | Country | Kind |
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2014-191084 | Sep 2014 | JP | national |