JP4282509B2 - Shaft holding device and paper feeding device equipped with the same - Google Patents

Description

  The present invention relates to a shaft holding device applicable to rollers and rollers used in a paper feeding device, a paper conveyance path, and the like of an image forming apparatus. The present invention also relates to a paper feeding device equipped with this shaft holding device.

  An image forming apparatus represented by a copying machine, a printer, and the like includes components such as a document feeding unit, a sheet feeding unit, an image forming unit, a transfer unit, and a fixing unit. A rotating body that rotates around an axis, such as a roller or a roller, is provided between the document feeding unit, the sheet feeding unit, and other components in order to transport the document or the sheet before printing. These rotators are for conveying a sheet through a nip formed by pressing the two rotators against each other, and are provided at various locations in the image forming apparatus.

In order to transport a sheet using a rotating body such as a roller or a roller, it is necessary to apply an appropriate nip pressure to bring the two rotating bodies into pressure contact with each other. For this reason, a method of pressing the rotating body using an elastic member such as a spring, a method capable of adjusting the nip pressure by using a motor, and the like have been proposed. Examples of these techniques can be found in US Pat.
JP 2003-335426 A (3rd page, FIG. 1-2) Japanese Patent Laid-Open No. 5-32356 (page 3-4, FIG. 1)

  In the paper feeding device described in Patent Document 1, the driven roller is urged by a spring that expands and contracts in a direction perpendicular to the axis of the shaft toward the nip with the paper feeding roller, and is pressed against the paper feeding roller. ing. As described above, a method of urging with a spring from a direction perpendicular to the axis of the shaft by a spring provided at a position that is a target of the shaft with respect to the nip is generally used as a method of pressing the two rotating bodies against each other. Widely used in However, this method requires a wide area in a direction perpendicular to the axis of the shaft in order to secure a space for mounting the spring. This leads to an increase in the size of the holding device for the rotating body, and may further increase the size of the sheet feeding device and the image forming apparatus provided with the shaft holding device. As the apparatus becomes larger, the manufacturing period and cost may increase significantly.

  The paper feeding device described in Patent Document 2 makes it possible to adjust a nip pressure with a feed roller (paper feeding roller) by using a motor with respect to a separation roller for separating paper that is being transported in an overlapping manner. Is. However, the use of a motor for adjusting the nip pressure increases the cost of the shaft holding device. Further, when such a shaft holding device is applied to a rotating body provided in various places of a paper feeding device or an image forming apparatus, the cost of these devices will be greatly increased. In addition, it is necessary to secure a space for arranging the motor, resulting in an increase in the size of the apparatus.

  The present invention has been made in view of the above points, and can be installed without requiring a wide area around the shaft, and a shaft capable of adjusting the nip pressure between rotating bodies by a simple mechanism. An object is to provide a holding device. Another object of the present invention is to provide a high-performance paper feeding device equipped with such a shaft holding device.

In order to solve the above-described problems, the present invention provides a shaft holding device that applies a biasing force in a direction perpendicular to the axis to a shaft disposed in the apparatus body, and one end of the shaft holding device is perpendicular to the axis of the shaft. The shaft is rotatably supported by a shaft, and is connected to an elastic member connecting portion at the other end. The shaft is inserted between both ends to support the shaft. A pressure member provided with a pressing part that presses the shaft side surface arranged at a position to be connected, one end connected to the connection part on the pressure member side, and the other end connected to the connection part on the main body side, The pressure member is provided with an elastic member that generates a moment about the support shaft and presses the shaft side surface by the pressing portion.

  In addition, the elastic member expands and contracts in a direction substantially parallel to the axis to apply a resilient force.

  Further, the distance between the pressing member side connecting portion and the main body side connecting portion is variable.

  A plurality of the main body side connecting portions are provided, and the elastic member is connected to any one of them.

  Further, the pressure member is attached so that a distance from the main body side connecting portion is variable.

  Further, the main body side connecting portion is provided so that a distance from the pressing member is variable.

  In the present invention, the shaft holding device is mounted on the paper feeding device.

  In the paper feeding device, the shaft holding device is used to hold a separation roller that separates the overlapped sheets.

According to the configuration of the present invention, in the shaft holding device that applies an urging force in a direction perpendicular to the axis, one end is rotatably supported by the support shaft that is perpendicular to the axis of the shaft, and the elastic member connecting portion is disposed at the other end. The shaft is inserted between both ends , and a shaft insertion port for supporting the shaft is provided, and a pressing portion for pressing the shaft side surface disposed at a position inside the shaft insertion port and facing the support shaft is provided. One end is connected to the pressurizing member and the connecting portion on the pressurizing member side, the other end is connected to the connecting portion on the main body side, and a moment around the support shaft is generated in the pressurizing member, and the pressing portion The elastic member that presses the side surface of the shaft is provided, so that an elastic member such as a spring is not disposed at a position that is a target of the shaft against the biasing destination of the shaft, and the shaft is attached in a direction perpendicular to the axis. You can give power. Therefore, when the two rotating bodies are brought into pressure contact with each other, a suitable nip pressure can be applied between the rotating bodies by a compact shaft holding device. Further, it is possible to reduce the size and cost of the sheet feeding device and the image forming apparatus provided with the shaft holding device.

  In addition, since the elastic member expands and contracts in a direction substantially parallel to the shaft to exert a resilient force, the increase in size of the shaft holding device in the direction perpendicular to the axis can be suppressed as much as possible. This makes it possible to further reduce the size of the shaft holding device.

  Further, since the distance between the pressure member side connecting portion and the main body side connecting portion is variable, the elastic force of the elastic member can be changed only by changing the distance between the two connecting portions. . As a result, even if the elastic member deteriorates due to, for example, secular change or the like and the resilience decreases, it is possible to easily cope with this. Moreover, even if the elastic member deteriorates, it is not necessary to replace it immediately, so that the running cost can be reduced.

  In addition, since the plurality of main body side connecting portions are provided, and the elastic member is connected to one of them, the elastic force of the elastic member can be simply changed by changing the connecting portion of the elastic member to another main body side connecting portion. Can be changed. Thereby, it can respond rapidly to the fall of the elastic force by deterioration etc. of an elastic member.

  Further, since the pressure member is attached so that the distance from the main body side connecting portion is variable, the biasing force of the shaft can be freely adjusted by changing the attachment position of the pressure member. . This is effective when it is difficult to move the connecting portion on the main body side due to the structure or space.

  In addition, since the main body side connecting portion is provided so that the distance from the pressure member is variable, it is possible to freely adjust the urging force of the shaft by changing the installation position of the main body side connecting portion. it can. This is effective when it is difficult to move the pressure member due to the structure or space.

  In the present invention, since the shaft holding device is mounted on the paper feeding device, the nip pressure between the rollers can be reduced by a simple mechanism without requiring a wide area around the rollers and rollers such as the paper feeding roller. It is possible to obtain a compact and high-performance sheet feeding device capable of adjusting the above.

  In the paper feeding device, since the shaft holding device is used to hold the separation roller for separating the overlapped sheets, a suitable nip pressure can be held on the separation roller. As a result, even if the elastic member that urges the separation roller is deteriorated or the separation roller is worn and the diameter of the roller is reduced, it is possible to reliably prevent double feeding of paper by simple adjustment. Become.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, as an example of a device, a paper feeding device arranged in the image forming apparatus is taken up. In this paper feeding device, it is assumed that the shaft holding device of the present invention is used for a separation roller for separating sheets that are being conveyed in an overlapping manner.

  First, the outline of the structure of the paper feeding device provided with the shaft holding device of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic vertical sectional view showing a sheet feeding device provided with a shaft holding device and its periphery, and FIG. 2 is a perspective view of the periphery of a separation roller as viewed from below.

  The sheet feeding device 1 is provided on the upper downstream side of the sheet feeding unit 100 of the image forming apparatus (not shown), that is, on the right side in FIG. In the paper feeding unit 100, paper P such as cut paper before printing is stacked and accommodated on a lift plate 102 provided in the paper tray 101. The paper feeding device 1 separates the paper P from the paper feeding unit 100 one by one and sends it out to the outside.

  The paper feed device 1 includes a forward feed roller 2, a paper feed roller 3, and a separation roller 4. The paper feed roller 3 is connected to a motor (not shown). The forward feed roller 2 and the paper feed roller 3 are connected to each other by a driven gear (not shown) through an intermediate gear 5. Thereby, when the paper feed roller 3 is rotated by the motor, the forward feed roller 2 is also rotated in the same direction as the paper feed roller 3.

  From the lower side of the forward feed roller 2, the downstream portion of the paper P stacked on the paper tray 101 is pushed up by the lift plate 102, and one of the uppermost layers of the paper P contacts. Then, the paper P is delivered to the paper feed roller 3 by the forward feed roller 2 and sent out of the paper feed unit 100 by the paper feed roller 3.

  The separation roller 4 is provided below the paper feed roller 3 in FIG. 1 and is in pressure contact with the paper feed roller 3. The paper P is inserted through a nip formed by the separation roller 4 and the paper feed roller 3 being pressed against each other. A motor is not connected to the separation roller 4. The separation roller 4 is rotated in accordance with the rotation of the paper feed roller 3 by being in pressure contact with the paper feed roller 3.

  As shown in FIG. 2, the separation roller 4 is provided with a torque limiter 6 on its shaft 4a. When the sheet P does not exist in the nip formed by the pressure contact between the separation roller 4 and the sheet feeding roller 3 or when only one sheet P enters, the torque limiter 6 acts to cause the separation roller 4 to move to the sheet feeding roller. 3 is rotated in the direction of feeding out the paper P. However, when a plurality of sheets P overlap with the nip, the torque limiter 6 does not act and the separation roller 4 stops rotating. As a result, the overlapped lower side paper P is not sent out, so that it is possible to prevent the problem of double feeding in which the paper P is overlapped and sent.

  As shown in FIG. 2, such a separation roller 4 is held by shaft holding devices 10 at both ends of its rotating shaft. The separation roller 4 has a suitable nip pressure in pressure contact with the paper feed roller 3 by the action of the shaft holding device 10.

  Next, a detailed configuration of the shaft holding device according to the first embodiment of the present invention will be described with reference to FIGS. 3 is a perspective view showing an external appearance of the shaft holding device, FIG. 4 is a perspective view showing a pressure member of the shaft holding device, and FIG. 5 is a perspective view showing only a base portion of the shaft holding device.

  In FIG. 3, the shaft holding device 10 includes a pressure member 11 that supports and presses the separation roller 4 that is a rotating body, a spring 12 that is an elastic member, and a main body side connecting portion 13 that connects the spring 12. Is provided.

  The pressure member 11 supports the separation roller 4 at the end of the shaft 4 a of the separation roller 4. In FIG. 4, the pressurizing member 11 includes a support shaft 11a at one end, and is supported rotatably about the support shaft 11a and the other end as a free end. The axis of the support shaft 11 a of the pressing member 11 is perpendicular to the axis of the shaft 4 a of the separation roller 4. At the free end portion of the pressing member 11, a pressing member side connecting portion 11b for connecting the spring 12 is provided, and a hook 11c for hooking the spring 12 is provided here. A shaft insertion port 11d is provided between the support shaft 11a of the pressurizing member 11 and the hook 11c. By inserting the shaft 4a of the separation roller 4 into the shaft insertion port 11d, the separation roller 4 is moved to the pressurizing member 11. Supported by A pressing portion 11e that presses the side surface of the shaft 4a of the separation roller 4 is provided inside the insertion port 11d and at a position facing the support shaft 11a. When the separation roller 4 is urged toward the paper feed roller 3, the support shaft 11a serves as a fulcrum, the hook 11c serves as a power point, and the pressing portion 11e serves as an action point.

  In FIG. 3, the pressing member 11 is supported by the frame 7 of the sheet feeding device 1 which is a main body. As shown in FIG. 5, a support shaft engaging portion 8 is provided on the frame 7. Three support shaft engaging portions 8 are provided, and these are arranged along the axial direction of the shaft 4 a of the separation roller 4. The pressing member 11 can be attached to any of the three support shaft engaging portions 8, thereby changing the distance from the main body side connecting portion 13.

  The spring 12, which is an elastic member, is constituted by a tension coil spring and is provided between the pressurizing member 11 and the main body side connecting portion 13 by being hooked on these members as shown in FIG. The spring 12 expands and contracts in a direction parallel to the axis 4a of the separation roller 4 to apply a resilient force.

  As shown in FIGS. 3 and 5, the main body side connecting portion 13 is fixed to the frame 7 of the paper feeding device 1 as the main body. The main body side connecting portion 13 is in the form of a boss protruding from the frame 7 to the side where the separation roller 4 is provided. A hook 13 a is provided at the tip of the main body side connecting portion 13, and the spring 12 can be hooked and connected thereto.

  Next, the operation of the shaft holding device will be described with reference to FIG. 6 in addition to FIG. FIG. 6 is a schematic vertical sectional view showing the shaft holding device of FIG. 3.

  3 and 6, the separation roller 4 is supported with its shaft 4 a inserted into the shaft insertion port 11 d of the pressure member 11. In the shaft insertion port 11d, the pressing portion 11e is in contact with the side surface of the shaft 4a. The pressurizing member 11 is supported in a support shaft engaging portion 8 provided on the frame 7 of the paper feeding device 1 so as to be rotatable about the support shaft 11a. The spring 12 is connected between the pressure member side connecting portion 11 b of the pressure member 11 and the main body side connecting portion 13.

  Since the spring 12 is connected to each connecting portion under tension, an elastic force is applied in a contracting direction parallel to the shaft 4a of the separation roller 4 (arrow A in FIG. 6). And the free end side in which the pressurizing member side connection part 11b of the pressurization member 11 was provided is pulled in the direction which approaches the main body side connection part 13, and the moment centering on the spindle 11a generate | occur | produces in the pressurization member 11. (FIG. 6 arrow B). As a result, the shaft 4a of the separation roller 4 is pressed by the pressing member 11, and a biasing force is applied in a direction perpendicular to the axis (arrow C in FIG. 6).

  In this way, one end is rotatably supported by the support shaft 11a perpendicular to the axis of the shaft 4a of the separation roller 4, the elastic member connecting portion 11b is disposed at the other end, and the side surface of the shaft 4a is disposed between both ends. One end is connected to the pressing member 11 provided with the pressing portion 11e to be pressed, and the connecting portion 11b on the pressing member 11 side, the other end is connected to the main body side connecting portion 13, and the pressing member 11 is A spring 12 that is an elastic member that generates a moment about the support shaft 11a and presses the side surface of the shaft 4a by the pressing portion 11e is provided. An urging force in a direction perpendicular to the axis can be applied to the shaft 4a without disposing an elastic member or the like. Therefore, a suitable nip pressure can be applied between the separation roller 4 and the paper feed roller 3 by the compact shaft holding device 10. Furthermore, the paper feeding device 1 provided with the shaft holding device 10 can be made compact and cost can be reduced.

  In addition, since the spring 12 expands and contracts in a direction substantially parallel to the shaft 4a of the separation roller 4 to exert a resilient force, it is possible to suppress the expansion of the size of the shaft holding device 10 in the direction perpendicular to the axis as much as possible. it can. As a result, the shaft holding device 10 can be further downsized.

  Further, since the distance between the pressure member side connecting portion 11b and the main body side connecting portion 13 is variable, the resilience of the spring 12 can be changed only by changing the distance between the two connecting portions. As a result, even if the spring 12 is deteriorated due to, for example, secular change or the like and the elasticity is reduced, it is possible to easily cope with this. Even if the spring 12 deteriorates, it is not necessary to replace it immediately, so that the running cost can be reduced.

  Further, since the pressure member 11 is attached so that the distance from the main body side connecting portion 13 is variable, the urging force of the shaft 4a of the separation roller 4 can be freely changed by changing the attachment position of the pressure member 11. Can be adjusted. That is, in FIG. 6, the pressure member 11 is attached to the support shaft engaging portion 8 closest to the main body side connecting portion 13, but when the biasing force of the shaft 4 a becomes weak, the attachment position of the pressure member 11 It is possible to increase the urging force of the shaft 4 a by changing the shaft engaging portion 8 further away from the main body side connecting portion 13. This is effective when it is difficult to move the main body side connecting portion 13 due to the structure or space. In the present embodiment, three support shaft engaging portions 8 are provided, but four or more support shaft engaging portions 8 may be provided.

  In the present invention, since the shaft holding device 10 is mounted on the paper feeding device 1 arranged in the image forming apparatus, the separation roller 4 can be separated by a simple mechanism without requiring a wide area around the separation roller 4. A compact and high-performance sheet feeding device 1 that can adjust the nip pressure between the sheet feeding roller 3 and the sheet feeding roller 3 can be obtained.

  Further, in the paper feeding device 1, the shaft holding device 10 is used to hold the separation roller 4 that separates the overlapped sheets, so that a suitable nip pressure can be held on the separation roller 4. Thereby, even if the spring 12 for urging the separation roller 4 is deteriorated or the separation roller 4 is worn and the diameter of the roller is reduced, the double feeding of the paper P is surely prevented by simple adjustment. Is possible.

  Next, a detailed configuration of the shaft holding device according to the second embodiment of the present invention will be described with reference to FIGS. 7 and 8. 7 is a schematic vertical sectional view showing the shaft holding device, FIG. 8 is a schematic vertical sectional view similar to FIG. 7, and shows a state where the spring is connected to the main body side connecting portion different from FIG. is there. Since the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 3 to 6, the same reference numerals are used for the same components as those of the first embodiment. The description is omitted.

  As shown in FIGS. 7 and 8, the frame 7 of the sheet feeding device 1 is provided with two main body side connecting portions 13. These main body side connecting portions 13A and 13B are arranged side by side along the axial direction of the shaft 4a of the separation roller 4. A hook 13a is provided at the tip of each main body side connecting portion 13, and the spring 12 can be hooked and connected thereto. When the spring 12 is connected to the main body side connecting portion 13A farther from the pressing member 11, the main body side connecting portion 13A is less than the main body side connecting portion 13B so that the closer main body side connecting portion 13B does not interfere with the spring 12. The height from the frame 7 is also high. For the same reason, in the spring 12, one half of the fixing member 11 side is a coil portion 12a and one half of the main body side connecting portion 13 is a rod-shaped portion 12b.

  In this way, a plurality of main body side connecting portions 13 are provided, and the spring 12 is connected to one of them. The power can be changed. That is, in FIG. 7, the spring 12 is connected to the main body side connecting portion 13B closer to the pressing member 11, but when the urging force of the shaft 4a becomes weak, the spring 12 is moved as shown in FIG. The urging force of the shaft 4a can be increased by connecting to the main body side connecting portion 13A far from the pressing member 11. Therefore, it is possible to quickly cope with a decrease in the elastic force due to the deterioration of the spring 12 or the like. In the present embodiment, two main body side connecting portions 13 are provided, but three or more main body side connecting portions 13 may be provided.

  Next, a detailed configuration of the shaft holding device according to the third embodiment of the present invention will be described with reference to FIGS. 9 and 10. 9 is a schematic vertical cross-sectional view showing the shaft holding device, and FIG. 10 is a schematic vertical cross-sectional view similar to FIG. 9, showing the state where the main body side connecting portion is attached at a position different from FIG. is there. Since the basic configuration of this embodiment is the same as that of the first and second embodiments, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. It shall be.

  As shown in FIGS. 9 and 10, the main body side connecting portion 13 is a member independent of the frame 7 of the sheet feeding device 1. The frame 7 is provided with two locking claws 9 for attaching the main body side connecting portion 13 side by side along the axial direction of the shaft 4 a of the separation roller 4. The main body side connecting portion 13 is provided with an engaging port 13b, and the main body side connecting portion 13 is supported by the frame 7 by inserting and engaging the engaging claw 9 of the frame 7 into the engaging port 13b.

  Thus, since the main body side connecting portion 13 is provided such that the distance from the pressure member 11 is variable, the attachment of the shaft 4a of the separation roller 4 is changed by changing the installation position of the main body side connecting portion 13. The power can be adjusted freely. That is, in FIG. 9, the main body side connecting portion 13 is attached to the locking claw 9 closer to the pressurizing member 11, but when the urging force of the shaft 4a becomes weaker, as shown in FIG. The urging force of the shaft 4a can be increased by attaching the side connecting portion 13 to the locking claw 9 far from the pressing member 11. In addition, in this embodiment, although the latching claw 9 is provided in two places, you may provide three or more places.

  Although the embodiment of the present invention has been described above, various modifications can be made without departing from the spirit of the present invention.

  For example, the pressure member 11 is pulled by the spring 12 to generate a moment around the support shaft 11 a in the pressure member 11. By pressing 11, a moment may be generated in the pressure member 11. Further, the spring 12 is not limited to a coil spring, and may be an elastic member such as a leaf spring, rubber, or sponge.

  Further, in the sheet feeding device 1, the separation roller 4 is supported by the shaft holding devices 10 provided at two places, but the number of the shaft holding devices 10 may be one.

  The present invention is applicable to all devices that require an urging force in a direction perpendicular to the axis of a shaft disposed in the device main body.

These are schematic vertical sectional views showing a sheet feeding device equipped with the shaft holding device of the present invention and its periphery. FIG. 2 is a perspective view of the periphery of a separation roller of the paper feeding device shown in FIG. 1 as viewed from below. These are perspective views which show the external appearance of the shaft holding device which concerns on the 1st Embodiment of this invention. FIG. 4 is a perspective view of a pressure member of the shaft holding device shown in FIG. 3. FIG. 4 is a perspective view of a base portion of the shaft holding device shown in FIG. 3. FIG. 4 is a schematic vertical sectional view of the shaft holding device shown in FIG. 3. These are model vertical sectional views showing a shaft holding device concerning a 2nd embodiment of the present invention. Fig. 7 is a schematic vertical sectional view of the shaft holding device similar to Fig. 7 and shows a state in which a spring is connected to a main body side connecting portion different from Fig. 7. These are model vertical sectional views showing a shaft holding device concerning a 3rd embodiment of the present invention. Fig. 9 is a schematic vertical sectional view of the shaft holding device similar to Fig. 9 and shows a state where the main body side connecting portion is attached at a position different from Fig. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper feeder 3 Paper feed roller 4 Separation roller 4a Shaft 7 Frame 8 Support shaft engaging part 10 Shaft holding device 11 Pressure member 11a Support shaft 11b Pressure member side connection part 11c Hook 11d Shaft insertion port 11e Press part 12 Spring (Elastic member)
13 Body side connecting part 13a Hook

Claims (8)

In a shaft holding device that applies an urging force in a direction perpendicular to the axis to a shaft arranged in the device body,
One end is rotatably supported by a support shaft perpendicular to the axis of the shaft, the other end is an elastic member connecting portion, the shaft is inserted between both ends , and a shaft insertion port for supporting the shaft, and the shaft A pressure member provided with a pressing portion that presses a shaft side surface disposed at a position facing the support shaft inside the insertion port, and one end of the pressure member side connecting portion are connected to the main body side. A shaft holding device comprising: an elastic member that connects the other end to the connecting portion, causes the pressure member to generate a moment about the support shaft, and presses the shaft side surface by the pressing portion. .   The shaft holding device according to claim 1, wherein the elastic member expands and contracts in a direction substantially parallel to the shaft to apply a resilient force.   The shaft holding device according to claim 1 or 2, wherein a distance between the pressure member side connecting portion and the main body side connecting portion is variable.   The shaft holding device according to claim 3, wherein a plurality of the main body side connecting portions are provided, and the elastic member is connected to any one of them.   The shaft holding device according to claim 3, wherein the pressure member is attached so that a distance from the main body side connecting portion is variable.   The shaft holding device according to claim 3, wherein the main body side connecting portion is provided such that a distance from the pressing member is variable.   A sheet feeding device comprising the shaft holding device according to any one of claims 1 to 6.   The sheet feeding device according to claim 7, wherein the shaft holding device is used to hold a separation roller that separates the overlapped sheets.

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