Embodiments described herein relate generally to an image forming device.
In the related art, an image forming device that eliminates static electricity from a print medium with a static elimination brush is known. In such an image forming device, the stronger the static elimination brush is brought into contact with the print medium, the higher the static elimination efficiency. However, if the static elimination brush is strongly brought into contact with the print medium, the front end of the print medium may be blocked by the static elimination brush. In this case, the image forming device causes a paper jam.
In general, according to one embodiment, an image forming device is described with reference to the drawings, taking an image forming device 1 as an example.
The image forming device 1 executes a process of forming an image on a printing medium S. The printing medium S is a sheet-like medium such as printing paper or a sticker mount.
The image forming device 1 includes a housing 10, a scanner unit 2, an image forming unit 3, a sheet supply unit 4, a conveyance unit 5, an ejection tray 7, a reversing unit 9, a control panel 8, and a control unit 6.
The housing 10 forms an outer shape of the image forming device 1.
The scanner unit 2 reads image information of an object to be copied based on brightness and darkness of light. The scanner unit 2 generates an image signal based on the read brightness and darkness of the light. The scanner unit 2 outputs the generated image signal to the image forming unit 3.
The image forming unit 3 forms an output image with a recording agent such as a toner based on an image signal received from the scanner unit 2 or an image signal received from the outside. Hereinafter, for convenience of explanation, this output image is referred to as a toner image. The image forming unit 3 transfers the formed toner image to the front surface of the printing medium S. The image forming unit 3 heats and pressurizes the toner image transferred to the front surface of the printing medium S to fix the toner image to the printing medium S.
The sheet supply unit 4 supplies the printing media S one by one, to the conveyance unit 5 at the timing when the image forming unit 3 forms a toner image. The sheet supply unit 4 includes a sheet containing unit 20 and a pickup roller 21.
The sheet containing unit 20 contains the printing media S of the predetermined size and type.
The pickup roller 21 picks up the printing media S one by one from the sheet containing unit 20. The pickup roller 21 supplies the extracted printing medium S to the conveyance unit 5.
The conveyance unit 5 conveys the printing medium S supplied from the sheet supply unit 4 to the image forming unit 3. The conveyance unit 5 includes a conveyance roller unit 23, a registration roller unit 24, an intermediate roller unit 25, a paper ejection roller unit 26, a detection unit 27, a static elimination brush 28, and a moving unit 281. In
The conveyance roller unit 23 is configured with two rollers of a paper feed roller and a separation roller that face each other. The conveyance roller unit 23 conveys the printing media S supplied from the pickup roller 21 one by one, to the registration roller unit 24. The conveyance roller unit 23 abuts the front end of the printing medium S in the conveyance direction to a nip N of the two rollers of the registration roller unit 24.
The registration roller unit 24 is configured with two rollers that face each other. The nip N is a nip of these two rollers. The registration roller unit 24 causes the printing medium S to bend at the nip N, to align the position of the front end of the printing medium S in the conveyance direction. The registration roller unit 24 conveys the printing medium S in response to the timing when the image forming unit 3 transfers the toner image to the printing medium S.
The intermediate roller unit 25 is configured with two rollers of a roller 251 and a roller 252 that face each other. The printing medium S after an image is formed by the image forming unit 3 is supplied to the intermediate roller unit 25. The intermediate roller unit 25 conveys the printing medium S supplied from the image forming unit 3 to the paper ejection roller unit 26.
The paper ejection roller unit 26 is configured with two rollers of a roller 261 and a roller 262 that face each other. The paper ejection roller unit 26 sandwiches the printing medium S supplied from the intermediate roller unit 25 between the roller 261 and the roller 262 and conveys the printing medium S in the conveyance direction. Accordingly, the paper ejection roller unit 26 conveys the printing medium S supplied from the intermediate roller unit 25 to the ejection tray 7. Accordingly, the paper ejection roller unit 26 is configured with two rollers that are the closest to the ejection tray 7 in the conveyance path. In other words, the paper ejection roller unit 26 is positioned on the downstream side from the image forming unit 3 in the conveyance path through which the printing medium S is conveyed. Specifically, the paper ejection roller unit 26 is positioned on the downstream side from a fixing device 33 in the image forming unit 3 in the conveyance path. The paper ejection roller unit 26 is an example of the roller unit.
Any one roller of the roller 261 and the roller 262 in the paper ejection roller unit 26 includes together with the roller a first gear 2611 that rotates about the same axis as the roller. For example, a case where the roller 261 includes the first gear 2611 is described. In
The detection unit 27 detects that the front end of the printing medium S passes a detection position SP determined in advance on the second conveyance path on the upstream side from the paper ejection roller unit 26 in the conveyance path. The detection unit 27 is a contact sensor that detects the contact with the printing medium S, for example, at the detection position SP. In this case, the detection unit 27 includes an actuator 271 and a sensor 272.
If the printing medium S passes the detection position SP, the actuator 271 is a rod-like member that rotates about the axis determined in advance by being pushed by the printing medium S. If the printing medium S passes the detection position SP, the actuator 271 may be a member of another shape that can rotate about an axis determined in advance by being pushed by the printing medium S.
The sensor 272 is a sensor that detects the actuator 271 rotating by being pushed by the printing medium S. The sensor 272 is, for example, an optical sensor, but may be a sensor of another type that can detect the actuator 271 rotating by being pushed by the printing medium S.
The detection unit 27 may be another sensor that can detect that the front end of the printing medium S passes the detection position SP. For example, the detection unit 27 may be an optical sensor that can detect that the front end of the printing medium S passes the detection position SP. In this case, the detection unit 27 is a non-contact sensor that detects the contact with the printing medium S at the detection position SP.
In the example illustrated in
The static elimination brush 28 eliminates static electricity of the printing medium S. The static elimination brush 28 includes a brush that eliminates the static electricity of the printing medium S by being brought into contact with the printing medium S and a main body that bundles the brush. The static elimination brush 28 may be configured with another member that can eliminate the static electricity of the printing medium S by being brought into contact with the printing medium S, instead of the brush.
The static elimination brush 28 is provided to be movable between two positions of a first position PA and a second position PB which are determined in advance. The position of the static elimination brush 28 is represented by a position of a portion determined in advance among portions in the static elimination brush 28. As an example, a case where the position of the static elimination brush 28 is represented by the position of the center of the brush in the static elimination brush 28 is described.
The first position PA is a position where a first conveyance path on the downstream side of the paper ejection roller unit 26 in the conveyance path and the static elimination brush 28 do not intersect. Therefore, if the static elimination brush 28 is positioned at the first position PA, the static elimination brush 28 may not be in contact with the printing medium that passes the first conveyance path. The first position PA is a position where the static elimination brush 28 can be positioned, and may be any position as long as the first conveyance path and the static elimination brush 28 do not intersect.
The second position PB is a position where the first conveyance path on the downstream side of the paper ejection roller unit 26 in the conveyance path and the static elimination brush 28 intersect. Specifically, the second position PB is a position where the brush in the static elimination brush 28 intersects with the first conveyance path. As an example, a case where the second position PB is positioned on the first conveyance path is described. In this case, the center of gravity of the brush in the static elimination brush 28 positioned at the second position PB overlaps the first conveyance path. Therefore, if the static elimination brush is positioned at the second position PB, the static elimination brush 28 is in contact with the printing medium that passes the first conveyance path.
Here,
Meanwhile,
The static elimination brush 28 is moved between the first position PA and the second position PB by the moving unit 281.
The moving unit 281 moves the static elimination brush 28 between the first position PA and the second position PB. The moving unit 281 may be any member as long as the member can move the static elimination brush 28 between the first position PA and the second position PB. As an example, a case where the moving unit 281 has the configuration illustrated in
The static elimination brush 28 is provided in the round rack 2813. Therefore, the static elimination brush 28 rotates according to the rotation of the round rack 2813 to move between the first position PA and the second position PB.
The second gear 2811 and the third gear 2812 are connected to each other via a torque limiter. Therefore, if the static elimination brush 28 is moved from the first position PA to the second position PB, the moving unit 281 can suppress the movement of the static elimination brush 28 to a position beyond the second position PB. If the static elimination brush 28 is moved from the second position PB to the first position PA, the moving unit 281 can suppress the movement of the static elimination brush 28 to a position beyond the first position PA.
In the example illustrated in
If the roller 261 rotates in the direction illustrated by an arrow AA illustrated in
If the roller 261 rotates in the direction illustrated by an arrow BA illustrated in
Instead of the configurations illustrated in
Hereinafter, the image forming unit 3 is specifically described.
The image forming unit 3 includes a plurality of image forming units 29, a laser scanning unit 30, an intermediate transfer belt 31, a transfer unit 32, and the fixing device 33.
The image forming units 29 includes photoconductor drums 291. The image forming units 29 form toner images according to an image signal received from the scanner unit 2 or an image signal received from the outside on the photoconductor drums 291. The plurality of image forming units 292, 293, 294, and 295 form toner images with toners of yellow, magenta, cyan, and black, respectively.
Chargers, developing devices, and the like are arranged in the periphery of the photoconductor drums 291. The chargers charge the front surfaces of the photoconductor drums 291. The developing devices contain the developers including yellow, magenta, cyan, and black toners. The developing devices develop the electrostatic latent images on the photoconductor drums 291. As a result, the toner images by toners of respective colors are formed on the photoconductor drums 291.
The laser scanning unit 30 deflects laser light LR to the charged photoconductor drum 291 and exposes the photoconductor drums 291. The laser scanning unit 30 exposes the photoconductor drums 291 of the image forming units 292, 293, 294, and 295 of the respective colors with the respective laser light LY, LM, LC, and LK. Accordingly, the laser scanning unit 30 forms the electrostatic latent images on the photoconductor drums 291.
The toner images on the front surfaces of the photoconductor drums 291 are primarily transferred to the intermediate transfer belt 31.
The transfer unit 32 transfers the toner images primarily transferred to the intermediate transfer belt 31 to the front surface of the printing medium S at a secondary transfer position.
The fixing device 33 heats and pressurizes the toner images transferred to the printing medium S to fix the toner images to the printing medium S.
The reversing unit 9 reverses the printing medium S in order to form the image on the back surface of the printing medium S. The reversing unit 9 reverses the front and the back of the printing medium S ejected from the fixing device 33 by switching back. The reversing unit 9 conveys the reversed printing medium S toward the registration roller unit 24.
The ejected printing medium S with the image formed is placed on the paper ejection tray 7.
The control panel 8 is a portion of an input unit that receives an input of the information for operating the image forming device 1 by an operator. The control panel 8 includes a touch panel, various hard keys, and the like.
The control unit 6 controls various units of the image forming device 1. The position of the control unit 6 illustrated in
The CPU 91 functions as the control unit 6 by the execution of the various programs stored in the memory 92 and the auxiliary storage device 93. The control unit 6 controls operations of functional units of the image forming device 1.
The auxiliary storage device 93 is configured by using a storage device such as a magnetic hard disk device or a semiconductor storage device. The auxiliary storage device 93 stores various kinds of information.
The communication unit 90 is configured to include a communication interface for connecting the own device to an external device. The communication unit 90 communicates with the external device via the communication interface.
Hereinafter, processes executed by the control unit 6 are described.
The control unit 6 waits until the detection unit 27 detects that the front end of the printing medium S passes the detection position SP (ACT 110).
If it is determined that the detection unit 27 detects that the front end of the printing medium S passes the detection position SP (ACT 110—YES), the control unit 6 starts time tracking (ACT 120).
Subsequently, the control unit 6 waits until first predetermined time determined in advance elapses from the timing when the time tracking starts in ACT 120 (ACT 130).
If it is determined that the first predetermined time elapses from the timing when the time tracking starts in ACT 120 (ACT 130—YES), the control unit 6 starts the rotation of the paper ejection roller unit 26 in the forward direction (ACT 140).
Accordingly, the control unit 6 can improve the efficiency of the elimination of the static electricity of the printing medium S by the static elimination brush 28 while the hindrance of the conveyance of the printing medium S by the static elimination brush 28 is suppressed. The first predetermined time may be determined by trial and error, may be determined by theoretical calculation, or may be determined by another method.
Subsequently, the control unit 6 waits until second predetermined time determined in advance elapses from the timing when the time tracking starts in ACT 120 (ACT 150). The second predetermined time is time determined so that the rotation of the paper ejection roller unit 26 in the forward direction continues while the rear end of the printing medium S finishes the passage of the intersection position. The second predetermined time may be determined by trial and error, may be determined by theoretical calculation, or may be determined by another method.
If it is determined that the second predetermined time elapses from the timing when the time tracking starts in ACT 120 (ACT 150—YES), the control unit 6 stops the rotation of the paper ejection roller unit 26 in the forward direction (ACT 160).
Subsequently, the control unit 6 starts the rotation of the paper ejection roller unit 26 in the reverse direction (ACT 170).
Next, the control unit 6 waits until third predetermined time determined in advance elapses from the timing when the time tracking starts in ACT 120 (ACT 180). The third predetermined time is time determined so that the static elimination brush 28 that starts the movement by the process of ACT 170 reaches the first position PA. The third predetermined time may be determined by trial and error, may be determined by theoretical calculation, or may be determined by another method.
If it is determined that the third predetermined time elapses from the timing when the time tracking starts in ACT 120 (ACT 180—YES), the control unit 6 stops the rotation of the paper ejection roller unit 26 in the reverse direction (ACT 190).
In the processes of the flowchart illustrated in
A graph GA illustrated in
A graph GB illustrated in
A graph GC illustrated in
Among the periods of time illustrated in
In the image forming device 1, the static elimination brush 28 described above is provided near the outlet of the paper ejection roller unit 26 on the ejection tray 7 side. Therefore, the image forming device 1 can eject the printing medium S to the ejection tray 7 immediately after the elimination of static electricity. In the image forming device 1, the static elimination brush 28 may be configured to be provided near the outlet of a roller unit different from the paper ejection roller unit 26.
The moving unit 281 described above has a configuration of moving the static elimination brush 28 between the first position PA and the second position PB by using the rotation of one of the two rollers in the paper ejection roller unit 26. However, the moving unit 281 may have the configuration including a mechanism that changes the direction of moving the static elimination brush 28 by using, for example, an electromagnetic clutch. The moving unit 281 may have a configuration including a mechanism that changes the direction of moving the static elimination brush 28, for example, via a plurality of gears.
As described above, the image forming device (the image forming device 1 in this example) includes an image forming unit (the image forming unit 3 in the example described above), a roller unit (the paper ejection roller unit 26 in the example described above), a static elimination brush (the static elimination brush 28 in the example described above), a moving unit (the moving unit 281 in the example described above), and a control unit (the control unit 6 in the example described above). The image forming device forms an image on a printing medium (the printing medium S in the example described above). The roller unit includes a first roller (the roller 261 in the example described above) that is position on a downstream side from the image forming unit in a conveyance path (a path illustrated by the dotted line L in the example described above) in which the printing medium is conveyed, a second roller (the roller 262 in the example described above) that is positioned on the downstream side from the image forming unit in the conveyance path and faces the first roller, sandwiches the printing medium between the first roller and the second roller, and conveys the printing medium in the first direction. The static elimination brush eliminates static electricity of the printing medium. The moving unit moves the static elimination brush between a first position (the first position PA in the example described above) that does not intersect a first conveyance path (the path illustrated by the dotted line LA in the example described above) on the downstream side of the roller unit in the conveyance path and a second position (the second position PB in the example described above) that intersects the first conveyance path. The control unit controls the moving unit during the conveyance of the printing medium, positions the static elimination brush at a position different from the second position until the front end of the printing medium passes the intersection position of intersecting the static elimination brush and the first conveyance path if the static elimination brush is positioned at the second position, and moves the static elimination brush to the second position after the front end of the printing medium passes the intersection position until the rear end of the printing medium passes the intersection position. Accordingly, the image forming device can efficiently eliminate static electricity of the printing medium while suppressing the occurrence of paper jam.
The image forming device further includes a detection unit (the detection unit 27 in the example described above) that detects that the front end of the printing medium passes the third position (the detection position SP in the example described above) in the second conveyance path (the path illustrated by the dotted line LB in the example described above) on the upstream side from the roller unit in the conveyance path, and may use the configuration in which the control unit controls the moving unit if the first time (the first predetermined time in the example described above) elapses after the detection unit detects that the front end of the printing medium passes the third position and moves the static elimination brush from the first position to the second position.
The image forming device may use the configuration in which the detection unit is a contact sensor that detects the contact with the printing medium at the third position.
The image forming device may use the configuration in which the detection unit includes an actuator (the actuator 271 in the example described above) that rotates about a first axis by being pushed by the printing medium if the printing medium passes the third position, and a sensor (the sensor 272 in the example described above) that detects the actuator rotating by being pushed by the printing medium.
The image forming device may use the configuration in which the detection unit is positioned the closest to the roller unit and upstream from the roller unit in the conveyance path and is position between two rollers (the roller 251 and the roller 252 of the intermediate roller unit 25 in the example described above) that convey the printing medium to the roller unit and the roller unit.
The image forming device may use the configuration in which the static elimination brush moves from the first position to the second position, if any one roller of the first roller and the second roller rotates in the first rotation direction (the forward direction in the example described above) and moves from the second position to the first position if the corresponding roller rotates in a second rotation direction (the reverse direction in the example described above) opposite to the first rotation direction, and the control unit rotates the corresponding roller in the first rotation direction, moves the static elimination brush in the second position, rotates the corresponding roller in the second rotation direction, and moves the static elimination brush to the first position.
The image forming device may use the configuration in which any one roller of the first roller and the second roller includes a first gear (the first gear 2611 in the example described above) that rotates about the same axis as the corresponding roller together with the corresponding roller, the moving unit includes a second gear (the second gear 2811 in the example described above) that meshes with the first gear, a third gear (the third gear 2812 in the example described above) that rotates about the same axis as the second gear together with the second gear, and a round rack (the round rack 2813 in the example described above) that rotates in response to the rotation of the third gear, and the static elimination brush is provided in the round rack that rotates about the rotation axis of the corresponding roller together with the round rack.
The image forming device may use the configuration in which the second gear and the third gear are connected to each other via a torque limiter.
The image forming device includes an ejection tray (the ejection tray 7 in the example described above) to which the printing medium is ejected after the image is formed by the image forming unit and may use the configuration in which the first roller and the second roller are the rollers that are the closest to the ejection tray in the conveyance path.
The image forming device may use the configuration in which the control unit moves any one roller of the first roller and the second roller from the second position to the first position after the rear end of the printing medium passes the intersection position.
A program for realizing the function of any configuration unit in the device described above (for example, the image forming device 1) may be recorded on a computer-readable recording medium, so that a computer system reads and executes the program. The term “computer system” as used herein includes hardware such as an Operating System (OS) and peripheral devices. The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a Compact Disk (CD)-ROM, or a storage device such as a hard disk built in a computer system. Furthermore, a “computer-readable recording medium” includes a medium that stores a program for a certain period of time such as a volatile memory (RAM) inside a computer system that serves as a server or client if a program is transmitted via a network such as the Internet or a communication line such as a telephone line.
Further, the above program may be transmitted from a computer system that stores this program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” that transmits a program refers to a medium having a function of transmitting information such as a network (communication network) such as the Internet or a communication line such as a telephone line.
Further, the above program may be to realize a portion of the above functions. Further, the above program may be a so-called difference file (difference program) that can implement the above functions in combination with a program already recorded in the computer system.
While certain embodiments have been described these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms: furthermore various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and there equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
Number | Name | Date | Kind |
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20050281598 | Hattori | Dec 2005 | A1 |
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