JP6589650B2 - Sheet material feeding apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet material feeding apparatus and an image forming apparatus including the sheet material feeding apparatus.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines, printers, and facsimiles include a sheet material feeding device that feeds a sheet material such as paper. The sheet material feeding device picks up the stacked sheet materials and separates them one by one. 2. Description of the Related Art Conventionally, there is known a sheet material feeding device that uses a feeding roller and a friction pad to separate multiple fed sheet materials. However, in the method using a friction pad to separate the sheet material, when there is no sheet material, the feeding roller may slide with respect to the friction pad, and the friction pad may deteriorate. When the friction pad deteriorates, the friction coefficient of the friction pad changes, and the performance of separating the sheet material may become unstable.

  Patent Document 1 discloses an apparatus having a separation member disposed to face a feeding roller that rotates in a paper feeding direction. The separation member is pivotally supported on an axis parallel to the feeding roller so as to be rotatable within a predetermined range. Further, the separating member is formed in a fan-shaped cross section in which the radius from the rotation center to the surface facing the paper path gradually increases in the paper feeding direction. Further, the separation member is formed by dividing the surface into two in the sheet feeding direction, with a front portion made of a high friction material and a rear portion made of a low friction material. In addition, the part formed with a high friction material has the same function as the above-mentioned friction pad.

  In the configuration of Patent Document 1, when there is no sheet material, the separating member is rotated by driving the feeding roller, and the feeding roller comes into contact with the surface of the low friction portion. For this reason, the feed roller does not slide with respect to the friction pad formed of the high friction material, and the friction pad can be prevented from being deteriorated.

JP 58-224935 A

  However, in the configuration of Patent Document 1, since the high-friction material and the low-friction material are continuously arranged on the same surface, when the positional accuracy when the feeding roller and the separating member are assembled is poor, the sheet The ability to separate materials can be unstable. This will be described with reference to FIGS. 17 and 18, reference numeral 100 denotes a separating member, reference numeral 101 denotes a high friction surface, and reference numeral 102 denotes a low friction surface. A broken line indicates a position where the separating member 100 and a feeding roller (not shown) abut when the sheet material is rolled. The same reference numerals and broken lines also apply to FIG. 19 described later.

  FIG. 17 shows a case where the feeding roller and the separating member 100 are assembled in a correct positional relationship. When the sheet material is rolled, the high friction surface 101 of the separating member 100 comes into contact with a feeding roller (not shown). FIG. 18 shows a case where the feeding roller and the separating member 100 are not assembled in the correct positional relationship. The position accuracy of the separating member 100 is poor, and the separating member 100 is disposed obliquely, and the contact portion between the feeding roller and the high friction surface 101 is small. In this case, there is a concern that the performance of separating the sheet material is deteriorated and the separation performance of the sheet material is varied.

  Moreover, in the structure of patent document 1, there is much contact | abutting in the boundary vicinity of a high friction surface and a low friction surface, and the said part may deteriorate by use. When the portion deteriorates, the contact portion between the feeding roller and the high friction surface 101 may become small as shown in FIG. In this case, there is a concern that the performance of separating the sheet material is deteriorated and the separation performance of the sheet material is varied.

  The present invention has been made in view of the above points, and an object thereof is to provide a sheet material feeding apparatus that can suppress deterioration of a member that separates sheet materials that have been multifed. Another object of the present invention is to provide a sheet material feeding apparatus that can hardly cause variations in sheet material separation performance caused by misalignment during assembly or deterioration with time. Another object of the present invention is to provide a highly reliable image forming apparatus that can stably prevent double feeding of sheet materials.

  In order to achieve the above object, a sheet material feeding device according to the present invention is a sheet material feeding device including a feeding unit that feeds a sheet material and a winding unit that is disposed to face the feeding unit. The winding portion includes a first portion including a high friction member that separates the multi-feed sheet material from the feeding portion, and a second portion including a low friction member having a lower friction coefficient than the high friction member. The high-friction member and the low-friction member are provided so as to be relatively displaceable.

  According to this configuration, since the high friction member and the low friction member are relatively displaceable, when there is no sheet material between the feeding unit and the separation unit, the feeding unit and the high friction member It is possible to prevent the high friction member (separation member) from deteriorating by reducing the friction force therebetween. Further, in this configuration, it is not necessary to continuously dispose the high friction member and the low friction member on the same surface, and it is difficult to be affected by a positional deviation during assembly or deterioration with time. That is, according to this configuration, variations in sheet material separation performance can be made difficult to occur.

  In the sheet material feeding device configured as described above, when the feeding unit is driven without a sheet material between the feeding unit and the winding unit, the high friction member and the low friction member are It is preferable that the low-friction member abuts on the feeding portion by being relatively displaced.

  In the sheet material feeding device having the above configuration, it is preferable that the high friction member and the low friction member are relatively displaced in conjunction with the movement of the feeding unit. According to this configuration, it is possible to eliminate the need to separately prepare a drive source for moving at least one of the high friction member and the low friction member.

  In the sheet material feeding device configured as described above, the high friction member may be configured to rotate and displace with respect to the low friction member.

  In the sheet material feeding device having the above-described configuration, it is preferable that the distance between the surface of the high friction member contacting the feeding portion and the rotation fulcrum gradually changes in the rotation direction. According to this configuration, it is possible to easily realize a configuration in which the high friction member and the low friction member are relatively displaced in conjunction with the movement of the feeding unit.

  It is preferable that the sheet material feeding device having the above-described configuration further includes a first urging portion that urges the high friction member rotated from a predetermined position in a direction to return to the predetermined position.

  In the sheet material feeding device configured as described above, the high friction member may be configured to move in parallel with a direction substantially parallel to the sheet material feeding direction and be displaced with respect to the low friction member.

  In the sheet material feeding device configured as described above, the high friction member is preferably inclined with respect to the sheet material feeding direction. According to this configuration, it is possible to easily realize a configuration in which the high friction member and the low friction member are relatively displaced in conjunction with the movement of the feeding unit.

  It is preferable that the sheet material feeding device configured as described above further includes a first urging unit that urges the high friction member that has been moved in parallel from a predetermined position in a direction to return the high friction member to the predetermined position.

  In the sheet material feeding device configured as described above, it is preferable that the high friction member and the low friction member abut on the feeding unit on the same plane. According to this configuration, it is possible to avoid a complicated structure around the feeding unit.

  In the sheet material feeding device configured as described above, it is preferable that the low friction member is provided on both sides of the high friction member in a direction substantially perpendicular to the sheet material feeding direction. According to this configuration, the pressing force applied to the feeding unit by the winding unit can be uniformly applied in a direction substantially perpendicular to the sheet material feeding direction.

  In the sheet material feeding device configured as described above, it is preferable that the first portion is supported by the second portion so as to be displaceable. According to this configuration, it is possible to avoid a complicated structure around the feeding unit.

  The sheet material feeding device configured as described above includes a support shaft that rotatably supports the second portion, and a second urging portion that urges the second portion toward the feeding portion. It may be the composition further provided.

  In the sheet material feeding device configured as described above, the second portion may also serve as a guide portion that guides conveyance of the sheet material.

  In order to achieve the above object, an image forming apparatus according to the present invention includes the sheet material feeding device having the above-described configuration.

  According to this configuration, it is possible to provide a highly reliable apparatus that can stably prevent double feeding of sheet materials.

  ADVANTAGE OF THE INVENTION According to this invention, the sheet | seat material feeding apparatus which can suppress deterioration of the member which isolate | separates the sheet | seat material multi-feeded can be provided. In addition, according to the present invention, it is possible to provide a sheet material feeding device that can hardly cause variations in sheet material separation performance caused by positional deviation during assembly or deterioration with time. Further, according to the present invention, it is possible to provide a highly reliable image forming apparatus that can stably prevent double feeding of sheet materials.

1 is a partial vertical sectional view of an image forming apparatus according to an embodiment of the present invention. It is a schematic perspective view which shows the structure of the feeding roller with which the sheet material feeding apparatus of 1st Embodiment of this invention is provided, and its periphery. It is a schematic perspective view which shows the structure of the winding part with which the sheet material feeding apparatus of 1st Embodiment of this invention is provided. It is a schematic perspective view which shows the structure of the 1st part with which the sheet material feeding apparatus of 1st Embodiment of this invention is provided. It is a schematic side view which shows the structure of the 1st part with which the sheet material feeding apparatus of 1st Embodiment of this invention is provided. In the sheet material feeding device according to the first embodiment of the present invention, it is a schematic diagram showing a relationship between a feeding roller and a separation unit when the feeding roller is stopped. In the sheet material feeding device according to the first embodiment of the present invention, the relationship between the feeding roller and the winding unit when the feeding roller is driven in a state where there is no sheet material between the feeding roller and the winding unit is shown. It is a schematic diagram. In the sheet material feeding device according to the first embodiment of the present invention, the relationship between the feeding roller and the separating portion when the feeding roller is driven and the sheet material is supplied between the feeding roller and the separating portion. It is a schematic diagram shown. It is a schematic side view which shows the relationship between the feeding roller with which the sheet | seat material feeding apparatus of 2nd Embodiment of this invention is equipped, and a winding part. It is a schematic perspective view which shows the structure of the winding part with which the sheet material feeding apparatus of 2nd Embodiment of this invention is provided. It is a schematic perspective view which shows the structure of the 1st part with which the sheet material feeding apparatus of 2nd Embodiment of this invention is provided. It is a schematic side view which shows the structure of the 1st part with which the sheet material feeding apparatus of 2nd Embodiment of this invention is provided. In the sheet material feeding device according to the second embodiment of the present invention, it is a schematic diagram showing the relationship between the feeding roller and the winding portion when the feeding roller is stopped. In the sheet material feeding device according to the second embodiment of the present invention, the relationship between the feeding roller and the winding unit when the feeding roller is driven in a state where there is no sheet material between the feeding roller and the winding unit is shown. It is a schematic diagram. In the sheet material feeding device according to the second embodiment of the present invention, the relationship between the feeding roller and the separating portion when the feeding roller is driven and the sheet material is supplied between the feeding roller and the separating portion. It is a schematic diagram shown. It is a schematic diagram which shows the basic concept of this invention. It is a schematic diagram for demonstrating the subject of the conventional sheet material feeding apparatus. It is a schematic diagram for demonstrating the subject of the conventional sheet material feeding apparatus. It is a schematic diagram for demonstrating the subject of the conventional sheet material feeding apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Outline of image forming apparatus>

  First, the image output operation of the image forming apparatus according to the embodiment of the present invention will be described while explaining the outline of the structure with reference to FIG. FIG. 1 is an example of a partial vertical sectional view of an image forming apparatus. In addition, the dashed-two dotted line with an arrow in a figure shows the conveyance path | route and conveyance direction of sheet materials, such as a paper.

  As shown in FIG. 1, the image forming apparatus 1 is a so-called tandem color copier, and includes an image reading unit 2 that reads an image of a document, a printing unit 3 that prints the read image on a sheet material, and printing conditions. An operation unit 4 for displaying inputs and operating statuses and a main control unit 5 are provided.

  The image reading unit 2 is a known unit that reads an image of a document placed on the upper surface of a platen glass (not shown) by moving a scanner (not shown). An image of a document is separated into three colors of red (R), green (G), and blue (B), and is converted into an electrical signal by a CCD (Charge Coupled Device) image sensor (not shown). Accordingly, the image reading unit 2 obtains image data for each color of red (R), green (G), and blue (B).

  The image data for each color obtained by the image reading unit 2 is subjected to various processes in the main control unit 5, and image data for each reproduction color of yellow (Y), magenta (M), cyan (C), and black (K). And stored in a memory (not shown) of the main control unit 5. The image data for each reproduction color stored in the memory is subjected to a process for correcting misregistration, and is then synchronized with the conveyance of the sheet material in order to perform optical scanning on the photosensitive drum 21 which is an image carrier. Read for each scan line.

  The printing unit 3 forms an image by an electrophotographic method, and transfers the image to a sheet material. The printing unit 3 includes an intermediate transfer belt 11 in which an intermediate transfer member is formed as an endless belt. The intermediate transfer belt 11 is wound around a driving roller 12, a tension roller 13 and a driven roller 14. A tension is applied to the intermediate transfer belt 11 by urging the tension roller 13 upward in FIG. 1 by a spring (not shown). The intermediate transfer belt 11 is rotated by the driving roller 12 counterclockwise in FIG.

  The driving roller 12 is pressed by the secondary transfer roller 15 that is opposed to the intermediate transfer belt 11. At the position of the driven roller 14, an intermediate transfer cleaning unit 16 provided so as to face the driven roller 14 with the intermediate transfer belt 11 interposed therebetween contacts the outer peripheral surface of the intermediate transfer belt 11. The intermediate transfer cleaning unit 16 scrapes and cleans toner remaining on the outer peripheral surface of the intermediate transfer belt 11 after the secondary transfer.

  Below the intermediate transfer belt 11, image forming units 20Y, 20M, 20C, and 20K corresponding to reproduction colors of yellow (Y), magenta (M), cyan (C), and black (K) are provided. In this description, the description of the identification symbols “Y”, “M”, “C”, and “K” is omitted unless it is particularly limited, and is generically referred to as “image forming unit 20”, for example. Sometimes. The four image forming units 20 are arranged in a line along the rotation direction of the intermediate transfer belt 11 from the upstream side to the downstream side in the rotation direction. The four image forming units 20 have the same configuration, and include a charging unit, a developing unit, a cleaning unit, and a primary transfer roller around the photosensitive drum 21 that rotates clockwise in FIG.

  Below the image forming unit 20, a scanning optical device 40 as an exposure unit is arranged. One scanning optical device 40 corresponds to the four image forming units 20. The scanning optical device 40 modulates four semiconductor lasers (not shown) according to the image gradation data of each reproduction color, and emits laser light corresponding to each reproduction color.

  Above the intermediate transfer belt 11, toner bottles 31 and toner hoppers 32 corresponding to the four image forming units 20 of the respective reproduction colors are provided. The developing unit and the toner hopper 32 are provided with a toner remaining amount detection unit (not shown) that detects the amount of toner inside each. Further, a toner replenishing device (not shown) is provided between the developing unit and the toner hopper 32 and between the toner hopper 32 and the toner bottle 31. When a decrease in the toner amount inside the developing unit is detected by the remaining amount detecting unit, the replenishing device is driven to replenish toner from the toner hopper 32 to the developing unit. Further, when the remaining amount detection unit detects a decrease in the toner amount inside the toner hopper 32, the replenishing device is driven to replenish the toner from the toner bottle 31 to the toner hopper 32. The toner bottle 31 is detachably attached to the apparatus main body, and can be replaced with a new one as appropriate.

  A sheet material feeding device 50 is provided below the scanning optical device 40. The sheet material feeding device 50 includes a sheet material storage unit 51 that stacks and stores the sheet material S. The sheet material S accommodated in the sheet material accommodating portion 51 is sent out to the sheet material conveyance path Q in order from the uppermost sheet using the pip-up roller 52 and the feeding roller 53. The sheet material S sent out from the sheet material accommodating portion 51 to the sheet material conveyance path Q reaches the position of the registration roller pair 71. Then, the registration roller pair 71 corrects the skew feeding of the sheet material S (skewing correction) and synchronizes with the rotation of the intermediate transfer belt 11, so that the contact portion (second part) between the intermediate transfer belt 11 and the secondary transfer roller 15 is obtained. The sheet material S is sent out toward the next transfer nip portion.

  In the image forming unit 20, an electrostatic latent image is formed on the surface of the photosensitive drum 21 by the laser light irradiated by the scanning optical device 40, and the electrostatic latent image is visualized as a toner image by the developing unit. . The toner image formed on the surface of the photosensitive drum 21 is primarily transferred to the outer peripheral surface of the intermediate transfer belt 11 at a position where the photosensitive drum 21 faces the primary transfer roller with the intermediate transfer belt 11 interposed therebetween. The toner images of the image forming units 20 are sequentially transferred to the intermediate transfer belt 11 at a predetermined timing along with the rotation of the intermediate transfer belt 11, so that yellow, magenta, cyan, black on the outer peripheral surface of the intermediate transfer belt 11. A color toner image is formed by superimposing the four color toner images.

  The color toner image primarily transferred to the outer peripheral surface of the intermediate transfer belt 11 is formed by contact of the intermediate transfer belt 11 and the secondary transfer roller 15 with the sheet material S sent in synchronization by the registration roller pair 71. Is transferred at the secondary transfer nip portion.

  A fixing portion 72 is provided above the secondary transfer nip portion. The sheet material S on which the unfixed toner image is transferred at the secondary transfer nip portion is sent to the fixing portion 72 and is sandwiched between the heating roller and the pressure roller, and the toner image is heated and pressurized to be applied to the sheet material S. Melt and fix. The sheet material S that has passed through the fixing unit 72 is discharged to a sheet material discharge unit 73 provided above the intermediate transfer belt 11.

  The operation unit 4 is provided on the front side of the image reading unit 2. For example, the operation unit 4 is used to input settings such as printing conditions such as the type and size of the sheet material S used for printing by the user, enlargement / reduction, and presence / absence of double-sided printing, and settings such as fax numbers and sender names in facsimile transmission. Accept input. In addition, the operation unit 4 also serves as a notification unit for notifying the user of the status, cautions, error message, and the like of the device on the display unit 4w.

  Further, the image forming apparatus 1 is provided with a main control unit 5 composed of a CPU (not shown), an image processing unit, and other electronic parts (not shown) for overall operation control. The main control unit 5 uses a central processing unit (CPU) and an image processing unit to control components such as the image reading unit 2 and the printing unit 3 on the basis of programs and data stored and input in a memory. Image forming operation and printing operation are realized.

The image forming apparatus 1 is characterized by the configuration of the sheet material feeding device 50. This will be described in detail below.
<First Embodiment of Sheet Material Feeding Device>

  As described above, the sheet material feeding device 50 includes the feeding roller 53 that feeds the sheet material S. The feed roller 53 rotates by driving a drive motor (not shown). The feeding roller 53 is an example of a feeding unit according to the present invention. The feeding unit is not limited to a roller shape, and may be, for example, a pad that moves in parallel. Such a feeding unit may be formed using, for example, a belt.

  FIG. 2 is a schematic perspective view showing the configuration of the feeding roller 53 provided in the sheet material feeding device 50 according to the first embodiment of the present invention and its surroundings. As illustrated in FIG. 2, the sheet material feeding device 50 includes a winding portion 60 that is disposed to face the feeding roller 53. By providing the winding unit 60, the sheet material feeding device 50 rolls the sheet material S and feeds the sheets one by one.

  FIG. 3 is a schematic perspective view illustrating the configuration of the separation unit 60 included in the sheet material feeding device 50 according to the first embodiment of the present invention. In FIG. 3, the X direction is a sheet material feeding direction, and the Y direction is a direction perpendicular to the sheet material feeding direction. As shown in FIG. 3, the winding part 60 has a first part 61 and a second part 62 which are separate parts.

  FIG. 4 is a schematic perspective view illustrating the configuration of the first portion 61 provided in the sheet material feeding device 50 according to the first embodiment of the present invention. FIG. 5 is a schematic side view showing the configuration of the first portion 61 provided in the sheet material feeding device 50 according to the first embodiment of the present invention. As shown in FIGS. 4 and 5, the first portion 61 includes a high friction member (separating member) 611 that separates the multi-feed sheet material S from the feeding roller 53. The high friction member 611 has a substantially fan shape in a side view. The high friction member 611 is made of, for example, a rubber material. The friction coefficient of the high friction member 611 is preferably about 0.4 to 1.9.

  The first portion 61 includes a support member 612 that supports the high friction member 611. Shaft portions 612a projecting in the Y direction (direction perpendicular to the X direction) are formed on both side surfaces of the support member 612 substantially parallel to the sheet material feeding direction (X direction). In addition, a connection portion 612b to which a first urging portion 55 (see FIG. 6) described later is coupled is formed on the lower surface of the support member 612. In the present embodiment, the high friction member 611 and the support member 612 are separate members, but they may be the same member. That is, the first portion 61 may be formed of only the high friction member 611.

  In this embodiment, the high friction member 611 forms a substantially fan-shaped member in a side view. However, this is only an example. The high friction member may form only a part of the substantially fan-shaped member. For example, the high friction member may form only the arc-shaped surface layer portion of the substantially fan-shaped member.

  The second portion 62 has a function of preventing deterioration of the high friction member 611. The second portion 62 also has a function of guiding the conveyance of the sheet material S. Referring to FIG. 3, the second portion 62 includes a low friction member 621 having a lower coefficient of friction than the high friction member 611. The low friction member 621 may form the entire second portion 62, but may form only a part of the second portion 62. For example, the low friction member 621 may form only a portion in contact with the feeding roller 53. In the present embodiment, the low friction member 621 forms the entire second part 62 having a substantially rectangular parallelepiped shape. The low friction member 621 is made of a resin such as polyacetal.

  The surface of the low friction member 621 facing the feeding roller 53 is a gentle convex surface with the substantially central portion in the sheet material feeding direction (X direction) being the top. That is, the low friction member 621 slightly protrudes toward the feeding roller 53. An opening 621a is formed at a substantially central portion of the convex surface. A space portion 621 b into which the first portion 61 is inserted is formed inside the low friction member 621. Part of the first portion 61 placed in the space 621b is exposed from the opening 621a. Specifically, the high friction member 611 is exposed.

  The low friction member 621 is formed with a support hole 621c through which the shaft portion 612a of the first portion 61 is inserted. The support hole 621c is substantially circular. The first portion 61 is supported by the low friction member 621 so as to be rotatable about the shaft portion 612a. That is, the first portion 61 is supported by the second portion 62 so as to be displaceable. The high friction member 611 and the low friction member 621 are relatively displaced. Specifically, the high friction member 611 rotates and is displaced with respect to the low friction member 621.

As shown in FIG. 5, the distance (radius) between the surface of the high friction member 611 that contacts the feeding roller 53 and the rotation fulcrum O gradually changes in the rotation direction. More specifically, the radius gradually increases from the upstream side to the downstream side in the sheet material feeding direction (X direction). For example, assuming polar coordinates with the rotation fulcrum O as the origin, the radius R (θ) may be expressed by the Archimedes curve equation shown in the following equation (1).
R (θ) = r + αθ (1)
α: constant θ: rotation angle

  The second portion 62 is rotatably supported on a support shaft 54 disposed in the device 50. Specifically, the second portion 62 includes a bearing 622 into which the support shaft 54 is inserted on the upstream side in the sheet material feeding direction. In the present embodiment, the bearing 622 is the same member as the low friction member 621, but may be formed as a separate member depending on circumstances.

  Next, the operation of the whirl unit 60 will be described. FIG. 6 is a schematic diagram illustrating the relationship between the feeding roller 53 and the separating unit 60 when the feeding roller 53 is stopped. The second portion 62 rotatably supported by the support shaft 54 is urged toward the feeding roller 53 by the second urging portion 56. The second urging portion 56 may be formed by a compression coil spring, for example. The first portion 61 that is rotatably supported by the second portion 62 is urged by the first urging portion 55 in a direction opposite to the rotation direction of the feeding roller 53 at the contact portion. The feeding roller 53 rotates in the clockwise direction in FIG. That is, the first portion 61 is urged clockwise in FIG. The first urging portion 55 may be formed of a tension coil spring, for example.

  Hereinafter, the position of the winding portion 60 (the first portion 61 and the second portion 62) shown in FIG. This initial position corresponds to a predetermined position of the present invention. In the initial position, a part of the first portion 61 protrudes from the opening 621a. Then, the high friction member 611 is pressed against the feeding roller 53.

  FIG. 7 is a schematic diagram illustrating a relationship between the feeding roller 53 and the separating unit 60 when the feeding roller 53 is driven in a state where there is no sheet material S between the feeding roller 53 and the separating unit 60. In FIG. 7, the feeding roller 53 rotates in the clockwise direction. When the feed roller 53 rotates, the first portion 61 counterclockwise against the biasing force of the first biasing portion 55 due to the frictional force between the feed roller 53 and the high friction member 611. To turn.

  As described above, the high friction member 611 has a structure in which the radius gradually changes. For this reason, the first portion 61 tries to move away from the feeding roller 53 by rotating counterclockwise. In response to this, the second portion 62 rotates around the support shaft 54 by the urging force of the second urging portion 56 and approaches the feeding roller 53. The rotation direction of the second portion 62 is the clockwise direction in FIG. When the first portion 61 rotates by a predetermined amount, the low friction member 621 of the second portion 62 is brought into a state of mainly contacting the feeding roller 53. Therefore, the frictional force between the feeding roller 53 and the high friction member 611 is reduced. That is, the deterioration of the high friction member 611 due to the rotation of the feeding roller 53 can be suppressed. Note that the rotational torque of the feeding roller 53 is smaller than when the feeding roller 53 is mainly in contact with the low friction member 621 and is in contact with only the high friction member 611.

  FIG. 8 is a schematic diagram illustrating a relationship between the feeding roller 53 and the separation unit 60 when the sheet supply S is supplied between the feeding roller 53 and the separation unit 60 by driving the supply roller 53. . The friction coefficient between the high friction member 611 and the sheet material S is smaller than the friction coefficient between the high friction member 611 and the feeding roller 53. For this reason, when the sheet material S is supplied, the first portion 61 rotates in a direction to slip to the sheet material S and return to the initial position by the urging force of the first urging portion 55. As a result, a state where a separation nip is formed between the feeding roller 53 and the high friction member 611 is obtained.

  When the friction coefficient between the feeding roller 53 and the sheet material S is μ1, the friction coefficient between the sheet material S and the sheet material S is μ2, and the friction coefficient between the high friction member 611 and the sheet material S is μ3. In addition, the relationship of μ1> μ3> μ2 holds. The force that the feeding roller 53 tries to move the sheet material S becomes larger than the force that the high friction member 611 tries to brake the sheet material S. For this reason, the sheet material S is fed by the rotation of the feeding roller 53.

  For example, it is assumed that two sheet materials are supplied to the separation nip. In this case, the force that the feeding roller 53 tries to move the upper sheet material S is larger than the force that the lower sheet material S tries to brake the upper sheet material S. For this purpose, the upper sheet material S is slid relative to the lower sheet material S by the rotation of the feeding roller 53. The force with which the high friction member 611 attempts to brake the lower sheet material S is greater than the force with which the upper sheet material S moves the lower sheet material S. For this reason, the movement of the lower sheet material S is restricted, and double feeding is prevented. Similarly, when three or more sheet materials S are supplied to the separation nip, only the uppermost sheet material S is fed, and the others are not fed. In addition, after the sheet material S has passed through the separation nip, the first portion 61 is rotated and the winding portion 60 is in the state shown in FIG. Further, when the feeding roller 53 is stopped, the separating unit 60 returns to the initial position.

  As described above, according to the sheet material feeding device 50 of the first embodiment, the friction between the feeding roller 53 and the high friction member 611 is performed using the contact between the low friction member 621 and the feeding roller 53. Deterioration of the high friction member 611 due to can be suppressed. Moreover, the high friction member 611 and the low friction member 621 are separate members, and they are not continuously arranged on the same surface. For this reason, compared with the conventional structure (refer FIGS. 17-19) by which a high friction member and a low friction member are continuously arrange | positioned on the same surface, it is hard to be influenced by the position shift at the time of an assembly | attachment, and a time-dependent deterioration. . For this reason, according to the sheet material feeding device 50 of the first embodiment, stable double feed prevention of the sheet material S can be expected.

In the present embodiment, the low friction member 621 is disposed on both sides of the high friction member 611 in the direction (Y direction) perpendicular to the sheet material feeding direction. Such a configuration is preferable because the pressing force applied to the feeding roller 53 by the separating unit 60 can be uniformly applied in the Y direction. However, this is merely an example, and the low friction member 621 may be disposed only on one side of the high friction member 611.
<Second Embodiment of Sheet Material Feeding Device>

  Next, the sheet material feeding device 50 according to the second embodiment will be described. In the description of the second embodiment, the description of the same parts as in the first embodiment will be omitted as appropriate, and different parts will be mainly described. Similarly to the first embodiment, the sheet material feeding device 50 according to the second embodiment also includes a feeding roller 53 and a winding unit 60. However, the detailed configuration of the splitting unit 60 is different.

  FIG. 9 is a schematic side view showing the relationship between the feeding roller 53 and the separation unit 60 included in the sheet material feeding device 50 according to the second embodiment of the present invention. FIG. 10 is a schematic perspective view illustrating the configuration of the separation unit 60 provided in the sheet material feeding device 50 according to the second embodiment of the present invention. In FIG. 10, the X direction is a sheet material feeding direction, and the Y direction is a direction perpendicular to the sheet material feeding direction. As shown in FIGS. 9 and 10, the winding part 60 has a first part 61 and a second part 62 which are separate parts.

  FIG. 11 is a schematic perspective view illustrating the configuration of the first portion 61 provided in the sheet material feeding device 50 according to the second embodiment of the present invention. FIG. 12 is a schematic side view illustrating the configuration of the first portion 61 provided in the sheet material feeding device 50 according to the second embodiment of the present invention. As shown in FIG.11 and FIG.12, the high friction member 611 contained in the 1st part 61 is a sheet form, and this point differs from 1st Embodiment. Other points of the high friction member 611 are the same as those of the first embodiment.

  The first portion 61 includes a support member 612 that supports the high friction member 611. The support member 612 is a substantially trapezoidal member in a side view. The high friction member 611 is disposed on the inclined surface of the support member 612. That is, the high friction member 611 is inclined with respect to the sheet material feeding direction (X direction). More specifically, the high friction member 611 is inclined so that the downstream side is higher than the upstream side in the sheet conveyance direction. Convex portions 612b are formed on both side surfaces of the support member 612 that are substantially parallel to the sheet material feeding direction (X direction). In the present embodiment, two convex portions 612b are formed on each side surface, but this number may be changed as appropriate. Also in this embodiment, the high friction member 611 and the support member 612 may be the same member.

  The configuration of the second portion 62 is substantially the same as the configuration of the first embodiment. The support holes 621c formed on both side surfaces substantially parallel to the sheet material feeding direction (X direction) of the low friction member 621 are not circular but extend in a direction substantially parallel to the sheet material feeding direction (X direction). The point which is a hole differs from 1st Embodiment. Similarly to the first embodiment, the second portion 62 is urged toward the feeding roller 53 by the second urging portion 56.

  The first portion 61 is supported by the second portion 62 so as to be movable in parallel. The moving direction of the first portion 61 is a direction substantially parallel to the sheet material feeding direction. That is, the high friction member 611 moves in a direction substantially parallel to the sheet material feeding direction and is displaced with respect to the low friction member 612. The first portion 61 is urged by the first urging portion 55 in a direction opposite to the rotation direction of the feeding roller 53 and the contact portion. The feeding roller 53 rotates in the clockwise direction in FIG. In FIG. 9, the first portion 61 is urged rightward by the first urging portion 55. The first urging portion 55 may be formed by a compression coil spring, for example.

  Next, the operation of the whirl unit 60 will be described. FIG. 13 is a schematic diagram illustrating a relationship between the feeding roller 53 and the separating unit 60 when the feeding roller 53 is stopped. Hereinafter, the position of the winding portion 60 (the first portion 61 and the second portion 62) shown in FIG. In the initial position, a part of the first portion 61 protrudes from the opening 621a. Then, the high friction member 611 is pressed against the feeding roller 53.

  FIG. 14 is a schematic diagram illustrating a relationship between the feeding roller 53 and the separating unit 60 when the feeding roller 53 is driven in a state where there is no sheet material S between the feeding roller 53 and the separating unit 60. In FIG. 14, the feeding roller 53 rotates in the clockwise direction. When the feeding roller 53 rotates, the first portion 61 feeds the sheet material against the urging force of the first urging portion 55 by the frictional force between the feeding roller 53 and the high friction member 611. Translate in the direction (X direction).

  The high friction member 611 is inclined so that the downstream side is higher than the upstream side in the sheet conveyance direction. For this purpose, the first portion 61 tends to move away from the feeding roller 53 by moving in parallel in the sheet material feeding direction. In response to this, the second portion 62 rotates around the support shaft 54 by the urging force of the second urging portion 56 and approaches the feeding roller 53. The turning direction of the second portion 62 is the clockwise direction in FIG. When the first portion 61 moves in parallel by a predetermined amount, the low friction member 621 of the second portion 62 mainly comes into contact with the feeding roller 53. Therefore, the frictional force between the feeding roller 53 and the high friction member 611 is reduced. That is, the deterioration of the high friction member 611 due to the rotation of the feeding roller 53 can be suppressed. Note that the rotational torque of the feeding roller 53 is smaller than when the feeding roller 53 is mainly in contact with the low friction member 621 and is in contact with only the high friction member 611.

  FIG. 15 is a schematic diagram illustrating a relationship between the feeding roller 53 and the separating unit 60 when the sheet roller S is supplied between the feeding roller 53 and the separating unit 60 by driving the feeding roller 53. . The friction coefficient between the high friction member 611 and the sheet material S is smaller than the friction coefficient between the high friction member 611 and the feeding roller 53. For this reason, when the sheet material S is supplied, the first portion 61 is translated in a direction in which the first portion 61 slips with respect to the sheet material S by the urging force of the first urging portion 55 and returns to the initial position. As a result, a state where a separation nip is formed between the feeding roller 53 and the high friction member 611 is obtained. As a result, as in the case of the first embodiment, the sheet material supply device 50 of the second embodiment can feed the sheet material S one by one.

As can be seen from the above, the sheet material feeding device 50 of the second embodiment can obtain the same effects as those of the first embodiment.
<Modifications>

  The configurations of the embodiment and the modification described above are merely examples of the present invention. The configuration of the embodiment and the modification may be changed as appropriate without departing from the technical idea of the present invention. In addition, a plurality of embodiments and modifications may be implemented in combination within a possible range.

  For example, in the above description, the second portion 62 is configured to be rotatable about the support shaft 54. However, this is only an example. For example, the second portion 62 may be configured to apply a pressing force to the feeding roller 53. For example, the second portion 62 may be configured to be movable instead of rotating.

  In the above description, the high friction member 611 and the low friction member 621 are relatively displaced in conjunction with the movement of the feeding roller 53. However, this is only an example. FIG. 16 is a schematic diagram showing the basic concept of the present invention. As shown in FIG. 16, this invention should just be the structure which has the high-friction member 611 and the low-friction member 621 in which the winding part is provided so that a relative displacement is possible. For example, the high friction member 611 and the low friction member 621 do not have to be interlocked with the feeding unit 53 or may be driven by different mechanisms. In addition, the high friction member 611 and the low friction member 621 may contact the feeding unit 53 on the same plane, but may contact the feeding unit 53 at different locations.

  In the above description, the configuration in which the image forming apparatus 1 is an image forming apparatus for color printing that transfers the toner image onto the paper P using the intermediate transfer belt 11 is shown. However, the application target of the present invention is not limited to such a model. The present invention is also applicable to, for example, an image forming apparatus that does not use an intermediate transfer belt, an image forming apparatus for monochrome printing, and the like.

  The present invention can be used in an image forming apparatus such as a copying machine.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 50 Sheet material feeding apparatus 53 Feed roller (feeding part)
54 support shaft 55 first urging portion 56 second urging portion 60 rolling portion 61 first portion 62 second portion 611 high friction member 621 low friction member S sheet material O rotation fulcrum

Claims (12)

A feeding section for feeding sheet material;
A winding portion disposed opposite to the feeding portion;
A sheet material feeding device comprising:
The whispering part is
A first portion including a high-friction member that separates the multi-feed sheet material from the feeding unit;
A second portion including a low friction member having a lower coefficient of friction than the high friction member;
Have
In conjunction with the movement of the feeding unit, the high friction member rotates and is displaced with respect to the low friction member,
The sheet material feeding device according to claim 1, wherein a distance between the surface of the high friction member that contacts the feeding unit and the rotation fulcrum gradually changes in the rotation direction . The first further comprising that the sheet material feeding apparatus according to claim 1, wherein the biasing portion of biasing the high friction member has rotated from a predetermined position in the direction of returning to the predetermined position. A feeding section for feeding sheet material;
A winding portion disposed opposite to the feeding portion;
A sheet material feeding device comprising:
The whispering part is
A first portion including a high-friction member that separates the multi-feed sheet material from the feeding unit;
A second portion including a low friction member having a lower coefficient of friction than the high friction member;
Have
In conjunction with the movement of the feeding unit, the high friction member moves in a direction substantially parallel to the sheet material feeding direction and is displaced with respect to the low friction member. Sheet material feeding device. The sheet material feeding apparatus according to claim 3 , wherein the high friction member is inclined with respect to a sheet material feeding direction. Sheet feeding apparatus according to claim 3 or 4, characterized in that it comprises first further biasing portion for biasing the high friction member which is translated from a predetermined position in the direction of returning to the predetermined position . When the feeding unit is driven with no sheet material between the feeding unit and the winding unit,
Wherein the high friction member above with a low-friction member is relatively displaced, the sheet material, wherein in any one of claims 1 to 5, low-friction member, characterized in that the contact with the feed unit Feeding device. Wherein the high friction member and the low friction member is a sheet material feeding apparatus according to any one of claims 1 to 6, characterized in that the abutment to the feeding portion on the same plane. The sheet material feeding device according to any one of claims 1 to 7 , wherein the low friction member is provided on both sides of the high friction member in a direction substantially perpendicular to a sheet material feeding direction. Feeding device. The sheet material feeding device according to any one of claims 1 to 8 , wherein the first portion is supported by the second portion so as to be displaceable. A support shaft that rotatably supports the second portion;
A second urging unit that urges the second part toward the feeding unit;
The sheet material feeding device according to claim 9 , further comprising: The second portion, the sheet material the sheet material feeding apparatus according to claim 1, any one of 10, characterized in that also serves as a guide portion for guiding the conveyance of the. An image forming apparatus comprising: a sheet feeding apparatus according to any one of claims 1 to 11.