Patent Application
20210362972
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2020-088065, filed on May 20, 2020, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a sheet conveying device and an image processing apparatus.
An image processing apparatus includes an automatic duplex copy unit (hereinafter referred to as “ADU”). In order to perform image processing on both front and back sides of the sheet, the ADU reverses the front and back of the sheet. The ADU includes a sheet conveying device that conveys a sheet. The sheet conveying device includes a roller, a motor, and a clutch. The clutch connects or disconnects drive of the motor with respect to the roller. The sheet conveying device controls the conveying of the sheet by connecting and disconnecting the clutch. Depending on the specifications of the idling torque of the clutch, there is a possibility that the time (hereinafter referred to as “roller stop time”) until the roller stops rotating if the clutch is disconnected extends, and the variation in the roller stop time increases.
A concern addressed by an exemplary embodiment is to provide a sheet conveying device and a document reading device capable of shortening the roller stop time if the clutch is disconnected and reducing the variation in the roller stop time.
A sheet conveying device of an exemplary embodiment includes a roller, a motor, a clutch, and a torque generator. The roller conveys a sheet. The motor is a driving source. The clutch connects or disconnects drive of the motor with respect to the roller. The torque generator applies a torque to the roller.
Hereinafter, a sheet conveying device and an image processing apparatus according to an embodiment will be described with reference to the drawings.
First, a first embodiment will be described with reference to
For example, the image processing apparatus 1 is a multi-function peripheral (MFP). The image processing apparatus 1 reads an image formed on a sheet-like recording medium (hereinafter referred to as “sheet”) such as a paper sheet to generate digital data (image file). The image processing apparatus 1 forms an image on a sheet using a toner based on the digital data.
The image processing apparatus 1 includes an ADU 2, a display unit 3, an image reading unit 4, an image forming unit 5, and a sheet tray 6.
The ADU 2 is an automatic double-sided copy unit. The ADU 2 is provided on the side portion of a main body of the image processing apparatus 1. The ADU 2 reverses the front and back of the sheet. For example, the front and back reversal of the sheet is performed if an image is formed on both the front and back sides of the sheet.
The display unit 3 operates as an output interface and displays characters or images. The display unit 3 also operates as an input interface and receives instructions from the user. For example, the display unit 3 is a touch panel type liquid crystal display.
For example, the image reading unit 4 is a color scanner. Color scanners include a contact image sensor (CIS) and a charge coupled device (CCD). The image reading unit 4 uses a sensor to read an image formed on the sheet and generate the digital data.
The image forming unit 5 forms an image on the sheet using a toner. The image forming unit 5 forms an image based on the image data read by the image reading unit 4 or the image data received from external equipment. For example, the image formed on the sheet is an output image called a hard copy, a printout, or the like.
The sheet tray 6 supplies a sheet to be used for image output to the image forming unit 5.
As illustrated in
A transfer in the image processing apparatus 1 includes a first transfer step and a second transfer step. In the first transfer step, the primary transfer roller 12 transfers an image (toner image) by a toner on a photoreceptor drum of each image forming unit to the intermediate transfer body 10. In the second transfer step, the secondary transfer unit 13 transfers the image to the sheet with the toner of each color laminated on the intermediate transfer body 10.
The intermediate transfer body 10 is an endless belt. The intermediate transfer body 10 is rotating in the direction of an arrow A in
The image forming unit 11 forms an image using a toner of each color (for example, five colors). A plurality of image forming units 11 are installed along the intermediate transfer body 10.
The primary transfer roller 12 transfers the toner image formed by the image forming unit 11 to the intermediate transfer body 10.
The secondary transfer unit 13 includes a secondary transfer roller 13a and a secondary transfer counter roller 13b. The secondary transfer unit 13 transfers the toner image formed on the intermediate transfer body 10 to the sheet.
The fixing device 14 fixes the toner image transferred onto the sheet to the sheet by heating and pressurizing. The sheet on which the image is formed by the fixing device 14 is discharged to the outside of the apparatus from a paper discharge unit 7 (refer to
Next, the ADU 2 will be described.
As illustrated in
The first roller 21 is a driving roller that rotates by being driven by a motor 31 (refer to
The second roller 22 is disposed above the first roller 21. The second roller 22 is a driven roller that rotates according to the rotation of the first roller 21 via a timing belt 34 (refer to
The third roller 23 opposes the first roller 21. The third roller 23 is a driven roller that rotates according to the rotation of the first roller 21.
The fourth roller 24 opposes the second roller 22. The fourth roller 24 is a driven roller that rotates according to the rotation of the second roller 22.
Next, a sheet conveying device 30 will be described.
The ADU 2 includes the sheet conveying device 30. As illustrated in
The first roller 21 is a roller (driving roller) that conveys the sheet. The first roller 21 includes a first shaft 21a, a first rotation body 21b, and a first pulley 21c.
The first shaft 21a has a columnar shape that extends in a sheet width direction. Here, the sheet width direction means a direction (paper surface depth direction in
The first rotation body 21b has a cylindrical shape coaxial with the first shaft 21a. The first rotation body 21b has an outer diameter larger than that of the first shaft 21a. A pair of first rotation bodies 21b are provided at the center of the first shaft 21a in the shaft direction at an interval.
The first pulley 21c has a disk shape coaxial with the first shaft 21a. The first pulley 21c is attached to one end portion of the first shaft 21a.
The second roller 22 is separated from the first roller 21 in the sheet conveying direction. The second roller 22 is a driven roller that rotates according to the rotation of the first roller 21. The second roller 22 includes a second shaft 22a, a second rotation body 22b, and a second pulley 22c.
The second shaft 22a has a columnar shape that extends in parallel to the first shaft 21a. For example, the second shaft 22a is made of metal.
The second rotation body 22b has a cylindrical shape coaxial with the second shaft 22a. The second rotation body 22b has an outer diameter larger than that of the second shaft 22a. A pair of second rotation bodies 22b are provided at the center of the second shaft 22a in the shaft direction at an interval.
The second pulley 22c has a disk shape coaxial with the second shaft 22a. The second pulley 22c is attached to one end portion of the second shaft 22a.
The timing belt 34 is bridged over the first pulley 21c and the second pulley 22c. The timing belt 34 is an endless belt. The rotation of the first roller 21 is transmitted to the second roller 22 through the first pulley 21c, the timing belt 34, and the second pulley 22c.
The motor 31 is a driving source of the first roller 21 (refer to
The clutch 32 connects or disconnects the drive of the motor 31 with respect to the first roller 21. For example, the clutch 32 is an electromagnetic clutch. In the connected state (the excited state of the electromagnetic clutch) of the clutch 32, the drive of the motor 31 is transmitted to the first roller 21. Meanwhile, in the disconnected state (the non-excited state of the electromagnetic clutch) of the clutch 32, the drive of the motor 31 is not transmitted to the first roller 21. The sheet conveying device 30 controls the rotation of the first roller 21 by connecting and disconnecting the clutch 32.
As illustrated in
The drive of the motor 31 may be transmitted to the first roller 21 via a power transmission mechanism other than the gear train such as a belt and a pulley. For example, an aspect of the power transmission mechanism can adopt various configurations according to the required specifications.
Next, the torque generator 40 will be described.
The torque generator 40 applies a torque to the first roller 21. As illustrated in
The torque generator 40 includes a sliding member 41 and a bias generator 42.
The sliding member 41 is slidable with respect to the first roller 21. For example, the sliding member 41 is made of a resin such as polyacetal (POM). For example, the sliding member 41 is preferably made of a material that can smoothly slide with respect to the first shaft 21a. The sliding member 41 is disposed between the first rotation body 21b and the bearing 25 in the shaft direction of the first shaft 21a. The sliding member 41 is disposed closer to the bearing 25 than the first rotation body 21b.
The sliding member 41 includes an annular portion 41a and a bulging portion 41b.
The annular portion 41a has an annular shape coaxial with the first shaft 21a. The annular portion 41a has a hole where the first shaft 21a extends through. The hole may generate a friction force with the first shaft 21a. The friction force effects as braking force. The annular portion 41a may have a hook shape, instead of the hole, to engage with the first shaft 21a. The annular portion 41a may have a shape to pinch the first shaft 21a. The annular portion 41a may have a shape to grab the first shaft 21a.
The bulging portion 41b bulges outward in the radial direction from a part of the annular portion 41a. The bulging portion 41b has a shape to which one end (first hook 42b) of the bias generator 42 can be attached.
The annular portion 41a and the bulging portion 41b are integrally formed of the same member.
For example, the bias generator 42 is a tension coil spring. The bias generator 42 biases the sliding member 41 in the direction of an arrow B1. The bias generator 42 always biases in the direction of pulling the sliding member 41. The bias generator 42 includes a spring 42a, the first hook 42b, and a second hook 42c.
The spring 42a is extensiblely disposed in a direction (the direction of the arrow B1) orthogonal to the first shaft 21a.
The first hook 42b is provided at the first end of the spring 42a. The first hook 42b is attached to the bulging portion 41b of the sliding member 41.
The second hook 42c is provided at the second end of the spring 42a. The second hook 42c is attached to a claw portion 52 that projects laterally from the base 50.
Reference numeral 53 in the drawing indicates a regulation wall portion provided on the base 50 for regulating the position (movement in the direction parallel to the first shaft 21a) of the spring 42a. A pair of regulation wall portions 53 is provided with the spring 42a therebetween.
The first hook 42b of the bias generator 42 is detachably attached to the bulging portion 41b of the sliding member 41. The second hook 42c of the bias generator 42 is detachably attached to the claw portion 52 of the base 50. The torque generator 40 can adjust (change) the torque with respect to the first roller 21 by replacing the bias generator 42.
For example, if the torque on the first roller 21 is maintained before and after the replacement of the bias generator 42, the bias generator is replaced with a bias generator having the same biasing force as that before the replacement.
For example, if the torque on the first roller 21 is made larger than that before the replacement of the bias generator 42, the bias generator is replaced with a bias generator having a larger biasing force than that before the replacement.
For example, if the torque on the first roller 21 is made smaller than that before the replacement of the bias generator 42, the bias generator is replaced with a bias generator having a smaller biasing force than that before the replacement.
As described above, the sheet conveying device 30 according to the embodiment includes the first roller 21, the motor 31, the clutch 32, and the torque generator 40. The first roller 21 conveys the sheet. The motor 31 is a driving source. The clutch 32 connects or disconnects the drive of the motor 31 with respect to the first roller 21. The torque generator 40 applies a torque to the first roller 21. With the above configuration, the following effects are obtained.
Since the torque generator 40 applies a torque to the first roller 21, the first roller 21 can be made to stop rotating if the clutch 32 is disconnected. In other words, even if the torque of the first roller 21 is light according to the specification of the idling torque of the clutch 32, a torque (braking force) for stopping the rotation of the first roller 21 is applied by the action of the torque generator 40. Therefore, it is possible to suppress an increase in time (roller stop time) until the rotation of the first roller 21 is stopped if the clutch 32 is disconnected. Therefore, the roller stop time if the clutch 32 is disconnected can be shortened, and the variation in the roller stop time can be reduced.
The torque generator 40 achieves the following effects by being disposed in the vicinity of the bearing 25 of the first roller 21.
Compared with a case where the torque generator 40 is disposed at a position far away from the bearing 25 of the first roller 21, it is easy to apply a constant torque to the first roller 21. Therefore, the variation in the roller stop time if the clutch 32 is disconnected can be further reduced.
The torque generator 40 includes the sliding member 41 that can slide with respect to the first roller 21, and the bias generator 42 that biases the sliding member 41. With the above configuration, the following effects are obtained.
Since a torque is applied to the first roller 21 via the sliding member 41, the rotation of the first roller 21 can be maintained in the connected state of the clutch 32, and the rotation of the first roller 21 can be made to stop rotating if the clutch 32 is disconnected. Therefore, it is possible to control the conveying of the sheet by connecting and disconnecting the clutch 32 with high accuracy. In addition, the configuration can be simplified as compared with a case where a driving device such as an actuator is provided as the torque generator 40.
The torque generator 40 achieves the following effects by being capable of adjusting the torque on the first roller 21 by replacing the bias generator 42.
By replacing the bias generator 42, a desired torque can be applied to the first roller 21. For example, if the member is replaced with a bias generator having a larger biasing force, the roller stop time if the clutch 32 is disconnected can be shortened more effectively, and the variation in the roller stop time can be reduced.
The image processing apparatus 1 includes the above-described sheet conveying device 30.
The sheet conveying device 30 can shorten the roller stop time if the clutch 32 is disconnected, and reduce the variation in the roller stop time. Therefore, the image processing apparatus 1 can smoothly perform image processing on both the front and back sides of the sheet.
Next, a second embodiment will be described with reference to
The bias generator 42 is not limited to biasing only the sliding member 41 that slides the first roller 21. The second embodiment is different from the first embodiment in that the bias generator 42 biases each of the sliding members 41 and 241 that slide the first roller 21 and the second roller 22.
As illustrated in
The torque generator 240 includes the plurality of sliding members 41 and 241 and the bias generator 42.
The plurality of sliding members 41 and 241 are the sliding member 41 (hereinafter referred to as “first sliding member 41”) slidable with respect to the first roller 21 and the second sliding member 241 slidable with respect to the second roller 22. For example, each of the sliding members 41 and 241 is made of a resin such as polyacetal (POM).
The second sliding member 241 is disposed between the second rotation body 22b and a bearing 225 (hereinafter referred to as “second bearing 225”) in the shaft direction of the second shaft 22a. The second sliding member 241 is disposed closer to the second bearing 225 than the second rotation body 22b.
The second sliding member 241 includes a second annular portion 241a and a second bulging portion 241b.
The second annular portion 241a has an annular shape coaxial with the second shaft 22a.
The second bulging portion 241b bulges outward in the radial direction from a part of the second annular portion 241a. The second bulging portion 241b has a shape to which the other end (second hook 42c) of the bias generator 42 can be attached.
The second annular portion 241a and the second bulging portion 241b are integrally formed of the same member.
The bias generator 42 is bridged between the first sliding member 41 and the second sliding member 241.
The bias generator 42 biases the first sliding member 41 in the direction of an arrow B21. The bias generator 42 biases the second sliding member 241 in the direction of an arrow B22.
The first hook 42b of the bias generator 42 is attached to the bulging portion 41b of the first sliding member 41. The second hook 42c is attached to the second bulging portion 241b.
According to the second embodiment, the plurality of sliding members 41 and 241 are provided. The plurality of sliding members 41 and 241 are the first sliding member 41 slidable with respect to the first roller 21 and the second sliding member 241 slidable with respect to the second roller 22. The bias generator 42 is bridged between the first sliding member 41 and the second sliding member 241. With the above configuration, the following effects are obtained.
Since the torque generator 240 applies a torque to each of the first roller 21 and the second roller 22, each of the first roller 21 and the second roller 22 can be made to stop rotating if the clutch 32 is disconnected. Therefore, the roller stop time if the clutch 32 is disconnected can be shortened more effectively, and the variation in the roller stop time can be reduced. [ 0047] Next, a third embodiment will be described with reference to
The second hook 42c of the bias generator 42 is not limited to being attached to the claw portion 52 of the base 50. The third embodiment is different from the first embodiment in that the second hook 42c is attached to a load adjustor 341.
As illustrated in
The load adjustor 341 can adjust the load on the first roller 21. For example, the load adjustor 341 is an actuator such as a solenoid. The load adjustor 341 includes a hook support unit 341a that supports the second hook 42c. The load adjustor 341 can move the hook support unit 341a in the direction (the direction of an arrow C1 or the direction of an arrow C2) orthogonal to the first shaft 21a.
The load adjustor 341 moves the hook support unit 341a in the direction of the arrow C1 if the load on the first roller 21 is made smaller than the reference load. In other words, the hook support unit 341a is brought closer to the first shaft 21a.
The load adjustor 341 moves the hook support unit 341a in the direction of the arrow C2 if the load on the first roller 21 is made larger than the reference load. In other words, the hook support unit 341a is brought further from the first shaft 21a.
The load control device 342 is a software functional unit that functions if a predetermined program is executed by a processor such as a central processing unit (CPU). The software functional unit includes a processor such as a CPU, a read only memory (ROM) for storing a program, a random access memory (RAM) for temporarily storing data, and the like. Further, at least a part of the load control device 342 may be an integrated circuit such as a large scale integration (LSI).
The load control device 342 controls the load adjustor 341 so as to adjust the load on the first roller 21 based on the total number (hereinafter referred to as “the number of conveyed sheets”) of sheets to be conveyed by a sheet conveying device 330. The load control device 342 stores the life data acquired by a durability test of the bias generator 42 or the like performed in advance. For example, the life data is data of a biasing force (spring force of the spring 42a) distribution map acquired by a predetermined number of conveyed sheets.
The biasing force of the bias generator 42 tends to decrease as the number of conveyed sheets increases. Therefore, in order to keep the load on the first roller 21 constant, it is necessary to control the load adjustor 341 so that the biasing force increases as the number of conveyed sheets increases. In the present embodiment, the load control device 342 controls the load adjustor 341 so as to make the hook support unit 341a far from the first shaft 21a for each predetermined number of conveyed sheets. For example, the load control device 342 controls the load adjustor 341 so as to make the hook support unit 341a far from the first shaft 21a for each of 300K conveyed sheets.
According to the third embodiment, the sheet conveying device 330 achieves the following effects by including the load adjustor 341 that can adjust the load on the first roller 21.
A desired load can be applied to the first roller 21. For example, if the load on the first roller 21 is made smaller than the reference load, the life of the bias generator 42 can be extended. Meanwhile, if the load on the first roller 21 is made larger than the reference load, the roller stop time if the clutch 32 is disconnected can be shortened more effectively, and the variation in the roller stop time can be reduced.
The sheet conveying device 330 achieves the following effects by including the load control device 342 that controls the load adjustor 341 so as to adjust the load on the first roller 21 based on the number of conveyed sheets.
By controlling the load control device 342, the optimum load can be automatically applied to the first roller 21.
Next, a modification example of the embodiment will be described.
The torque generator 40 of the embodiment is disposed in the vicinity of the bearing 25 of the first roller 21. On the other hand, the torque generator 40 may be disposed at a position far away from the bearing 25 of the first roller 21. For example, the torque generator 40 may be disposed closer to the end portion on the side opposite to the bearing 25 of the first roller 21 in the shaft direction of the first shaft 21a. For example, the torque generator 40 may be disposed between a pair of first rotation bodies 21b.
The bias generator 42 of the embodiment is a tension coil spring. On the other hand, the bias generator 42 may be a compressive coil spring. For example, the bias generator 42 may not have the first hook 42b and the second hook 42c. For example, the bias generator 42 may bias the sliding member 41 in a direction opposite to the direction of the arrow B1. In other words, the bias generator 42 may always bias in the direction of pushing the sliding member 41.
The image processing apparatus 1 according to the embodiment is an image forming apparatus. On the other hand, the image processing apparatus may be a decoloring device. In this case, the fixing device may be a decoloring device. The decoloring device performs a process of decoloring (erasing) an image formed on a sheet with a decolorable toner.
According to at least one of the above-described embodiments, since the torque generator applies a load to the roller, the roller can be made to stop rotating if the clutch is disconnected. Therefore, the roller stop time if the clutch is disconnected can be shortened, and the variation in the roller stop time can be reduced.
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 their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-088065 | May 2020 | JP | national |
