JP4193936B2 - Paper feeding device and image forming apparatus. - Google Patents

Description

  The present invention relates to a sheet feeding device and an image forming apparatus such as a copying machine, a printer, and a facsimile machine including the sheet feeding device.

  Currently, in the image forming apparatus, with the colorization of the output image, different types of recording materials may be used according to the type of the output image. For example, when a color image is output, a high-density recording material is used to improve the color of the image, and a conventional recording material is used for monochrome image output. As a paper feeding device of such an image forming apparatus, there is a paper feeding device having a configuration capable of storing recording materials of different densities and recording materials of different sizes using a single paper feeding tray.

  This paper feeding device is provided in the inside of a paper feed tray, and pulls up (or pushes up) a bottom plate on which recording materials are stacked on a top by a spring, and the uppermost recording material stacked on the bottom plate Is pressed against the feed roller. The sheet feeding roller is driven to rotate to feed the recording materials one by one.

  As described above, when different types of recording materials can be stored in the paper feed tray, the weight of the recording material bundle varies depending on the density and size of the recording materials. At this time, in order to stably operate the paper feeding mechanism, it is necessary to stabilize the pressure contact force between the recording material and the paper feeding roller, and the tensile force of the spring that pulls up the bottom plate of the paper feeding tray on which the recording material bundle is loaded is set. It is necessary to adjust according to the type and size of the recording material. In other words, if the tensile force of the spring against the bottom plate is constant regardless of changes in the type and size of the recording material loaded on the bottom plate, the weight increases in the case of high-density recording materials and large-size recording materials. The tensile force of the spring is insufficient with respect to the weight of the recording material, and the press contact force between the recording material and the paper feeding roller is reduced, causing the recording material to not feed. In some cases, the tensile force of the spring becomes too large with respect to the weight of the recording material, and the pressure contact force between the recording material and the paper feeding roller becomes excessive, which causes problems such as easy occurrence of double feeding of the recording material. .

  Therefore, in Patent Document 1, a push-up mechanism that pushes up the bottom plate is driven by a motor to control the pressure contact force between the recording material and the paper feed roller.

Japanese Patent Laid-Open No. 2002-167058

  However, since the technique of Patent Document 1 needs to use a motor for pushing up the bottom plate, electrical control is required, and the number of parts increases, resulting in a problem that the cost increases as a whole. Further, since the technique of Patent Document 1 is a technique for an image forming apparatus configured to pull out a paper feed tray in a direction orthogonal to the recording material conveyance direction, image formation that requires downsizing of a device body such as a small printer is required. In the apparatus, it is necessary that the sheet feeding tray withdrawing direction is a direction toward the downstream side of the recording material feeding direction by the sheet feeding roller (for example, the feeding direction of the sheet feeding tray is the same as the conveying direction of the recording material). Therefore, it is not optimal.

  An object of the present invention is to realize a structure for adjusting the pressure contact force between a recording material placed on a paper feed tray and a paper feed roller at a low cost.

  An object of the present invention is to supply a recording material placed on a paper feed tray and feed even in an image forming apparatus in which the paper feed tray is drawn out in the direction toward the downstream side of the recording material feeding direction by the paper feed roller. It is to be able to adjust the pressure contact force with the paper roller.

  According to a first aspect of the present invention, there is provided a sheet feeding device that is detachably mounted in a loading port formed in the apparatus main body, and a recording material that is laid up and down at the bottom of the sheet feeding tray and is stacked. The bottom plate to be placed is in contact with the recording material placed on the bottom plate of the paper feed tray attached to the mounting opening and placed on the bottom plate, and rotated toward the feeding direction of the recording material. A paper feed roller to be driven, an arm attached to the paper feed tray with a pivot as a fulcrum, and an arm that slides upward and downward toward the mounting port. A guide member having a guide surface for guiding freely and fixed to the apparatus main body, and one end connected to the free end side of the bottom plate and the other end connected to the arm so as to stand on the bottom plate. A recording material placed on the bottom plate by applying a force An urging member that is pressed against the paper feeding roller, a position adjusting mechanism that holds the support shaft of the arm movably in a direction orthogonal to the axial direction, and positions the support shaft; An operation member for operating the position adjustment mechanism.

  According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the position adjusting mechanism positions the support shaft at a position set for each of a plurality of types of recording materials.

  According to a third aspect of the present invention, in the paper feeding device according to the first or second aspect, a plurality of the arms are provided, and the position adjusting mechanism synchronizes the positioning operations of the support shafts of the plurality of arms. Is provided.

  According to a fourth aspect of the present invention, in the paper feeding device according to the third aspect, the operation member is single.

  According to a fifth aspect of the present invention, in the paper feeding device according to any one of the first to fourth aspects, the pulling-out direction of the paper feeding tray is a direction toward the downstream side of the feeding direction of the recording material by the paper feeding roller. is there.

  According to a sixth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to fifth aspects, and an image forming section that performs an image forming operation on a recording material fed by the paper feeding apparatus. And comprising.

  According to the present invention, a structure for adjusting the pressure contact force between the recording material placed on the paper feed tray and the paper feed roller can be realized at low cost. Further, even in an image forming apparatus in which the paper feed tray is drawn out in the direction toward the downstream side of the recording material feeding direction by the paper feed roller, the recording material placed on the paper feed tray and the paper feed roller The pressure contact force can be adjusted.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows the overall structure of a printer 1 that is an image forming apparatus. The printer 1 includes a paper feeding device 3 provided in a lower portion of a printer main body 2 that is an apparatus main body, and a printer main body 2 provided in, for example The image forming unit includes an electrophotographic image forming unit (not shown), and the image forming unit forms an image on the recording material S fed from the paper feeding device 3 to the image forming unit.

  The paper feeding device 3 will be described. A mounting port 4 is formed in the lower part of the printer main body 2, and a paper feed tray 5 is mounted in the mounting port 4 so that it can be pulled out. A bottom plate 7 is provided at the bottom of the paper feed tray 5 so as to be able to rise and fall in the vertical direction with the support shaft 6 as a fulcrum. A recording material S is placed on the bottom plate 7. Here, FIG. 1 shows a state in which the paper feed tray 5 is pushed into the mounting opening 4, and FIG. 2 shows a state in which the paper feed tray 5 is pulled out from the mounting opening 4.

  In the printer main body 2, it is arranged above the paper feed tray 5 pushed into the mounting opening 4, and is rotated by abutting against the uppermost recording material S placed on the bottom plate 7 to thereby record it. A paper feed roller 8 for feeding the material S in the feed direction is provided. Here, the drawing direction of the sheet feeding tray 5 is a direction toward the downstream side of the feeding direction of the recording material S by the sheet feeding roller 8.

  Further, the paper feeding device 3 adjusts the pressure contact force for optimizing the pressure contact force of the recording material S placed on the bottom plate 7 of the paper feed tray 5 to the paper supply roller 8 regardless of the type of the recording material S. A mechanism 9 is provided.

  3 is a plan view showing the pressing force adjusting mechanism 9, FIG. 4 is an enlarged perspective view showing a part of the pressing force adjusting mechanism 9, and FIG. 5 shows the pressing force adjustment in a state where the switching lever 24 is located at the first position. FIG. 6 is a perspective view showing the pressure contact force adjusting mechanism 9 in a state where the switching lever 24 is located at the second position, and FIG. 7 is an overall view of the printer 1 where the support shaft 14 is located at the second position. FIG.

  The pressing force adjusting mechanism 9 includes a bottom plate 7, an arm 10, a guide member 11, a tension spring 12 that is a biasing body, a position adjusting mechanism 13, and the like provided in the sheet feeding tray 5.

  The arm 10 is a member attached to the paper feed tray 5 via a position adjustment mechanism 13 and the like so as to be rotatable in the vertical direction with the support shaft 14 as a fulcrum. On the free end side of the arm 10, a cylindrical sliding portion 15 that protrudes in a direction orthogonal to the longitudinal direction of the arm 10 is formed. As shown in FIG. 3, a pair of arms 10 are provided on both sides in the width direction perpendicular to the loading / unloading direction when the paper feed tray 5 is loaded / unloaded into / from the mounting opening 4.

  As shown in FIGS. 1 and 4, the guide member 11 is a member formed in a fixed position at positions inside the printer main body 2 and on both sides of the mounting opening 4. A guide surface 11a is formed which gradually inclines upward as it goes to the back side. The guide member 11 is positioned so that the sliding portion 15 of the arm 10 slides on the guide surface 11 a when the paper feed tray 5 is inserted into and removed from the mounting opening 4.

  The tension spring 12 has one end connected to the free end side of the bottom plate 7 and the other end connected to the free end side of the arm 10. When the paper feed tray 5 is pushed into the mounting opening 4, the tension spring 12 is moved upward with the sliding portion 15 sliding on the guide surface 11 a as the movement of the paper feeding tray 5 is moved. By rotating, an urging force in a direction to stand on the bottom plate 7 is applied.

  The arm 10, the guide member 11, and the tension spring 12 are arranged as shown in FIG. A guide groove 16 is formed along the longitudinal direction of the guide member 11 at the central portion in the width direction of the guide member 11, which is a direction orthogonal to the direction in which the paper feed tray 5 is put in and taken out. The arm 10 and the tension spring 12 move in the guide groove 16. Although not shown in FIG. 4, both end portions 11 b in the width direction of the guide member 11 are fixed to the printer main body 2.

  As shown in FIG. 1, when the paper feed tray 5 is pushed into the mounting port 4, the sliding portion 15 rises along the guide surface 11a. As a result, the bottom plate 7 is rotated by the urging force acting from the tension spring 12 in a direction to stand up with the support shaft 6 as a fulcrum, and the recording material S placed on the bottom plate 7 is moved to the lower outer periphery of the paper feed roller 8. Press contact with the surface.

  The position adjusting mechanism 13 is a mechanism that adjusts the position of the support shaft 14 of the arm 10, and is orthogonal to the loading / unloading direction when the sheet feeding tray 5 is loaded / unloaded into / from the mounting opening 4 as shown in FIGS. 1 and 3. A base shaft 17 which is a synchronizing means pivotally supported on the paper feed tray 5 with the width direction as an axial direction, and one end fixed to the base shaft 17 and rotatably provided around the axis of the base shaft 17 with the base shaft 17 as a fulcrum. Two link members 18 and a positioning portion 19 are provided.

  The link member 18 is provided at both ends of the base shaft 17 corresponding to each arm 10, and the free end which is the other end of the link member 18 rotatably supports the support shaft 14 of the arm 10. Therefore, the support shaft 14 of the arm 10 moves around the axis of the base shaft 17 by the rotation of the link member 18 with the base shaft 17 as a fulcrum as the base shaft 17 rotates. That is, the support shaft 14 is held by the position adjusting mechanism 13 so as to be movable in a direction orthogonal to the axial direction.

  As shown in FIGS. 5 and 6, the positioning portion 19 rotates with respect to the paper feed tray 5 with a rail 20 provided on the base shaft 17 and a shaft 21 provided in a direction orthogonal to the base shaft 17 as fulcrums. And a rotation member 23 which is provided so as to be movable and has a fitting portion 22 formed at a free end thereof. The fitting portion 22 is slidably fitted to the rail 20. The rail 20 includes first and second parallel portions 20a and 20b that are parallel to the axial direction of the base shaft 17 and are displaced from each other in the rotational direction of the base shaft 17, and the first and second parallel portions 20a and 20b. It is comprised from the connection part 20c to connect. The rotation member 23 is provided with a switching lever 24 that is an operation member for operating the rotation member 23. The switching lever 24 is exposed from an opening 25 (see FIG. 2) formed in the paper feed tray 5 so that an operator can operate the switching lever 24. In this structure, the switching lever 24 is operated, the rotation member 23 is rotated about the shaft 21 and the fitting portion 22 is moved, so that the rail 20 is pushed by the fitting portion 22 and the base shaft 17 is rotated. When the fitting portion 22 is positioned at the first or second parallel portion 20a, 20b, the base shaft 17 is positioned by the switching lever 24 and the rotation of the base shaft 17 is restricted. Here, the position of the switching lever 24 when the fitting portion 22 is located at the first parallel portion 20a is the first position (see FIG. 5), and the fitting portion 22 is located at the second parallel portion 20b. The position of the switching lever 24 when it is in the second position is the second position (see FIG. 6).

  In the position adjustment mechanism 13, the position of the support shaft 14 in the state where the switching lever 24 is located at the first position is also set to the first position (see FIG. 1). From this state, when the switching lever 24 is operated toward the second position so that the fitting portion 22 passes through the connecting portion 20c and moves to the second parallel portion 20b, the fitting portion 22 moves. Accordingly, the base shaft 17 is rotated, and the link member 18 is rotated by this rotation, and the position of the support shaft 14 is moved to the downstream side in the drawing direction of the paper feed tray 5 from the first position. The position of the support shaft 14 at this time is the second position (see FIG. 7). At this time, the free end of the arm 10 supporting the other end of the tension spring 12 approaches one end of the tension spring 12 supported by the bottom plate 7. Accordingly, when the support shaft 14 is positioned at the second position, the operating length of the tension spring 12 is shorter than when the support shaft 14 is positioned at the first position, and the tension spring 12 is The urging force that pulls up 7 is reduced. Further, from this state, when the switching lever 24 is operated toward the first position so that the fitting portion 22 passes through the connecting portion 20c and moves to the first parallel portion 20a, the fitting portion 22 moves. Accordingly, the base shaft 17 is rotated, and the link member 18 is rotated by this rotation, and the position of the support shaft 14 is moved from the second position to the first position. At this time, the free end of the arm 10 supporting the other end side of the tension spring 12 moves away from one end side of the tension spring 12 supported by the bottom plate 7, and the operating length of the tension spring 12 becomes longer. The urging force that 12 pulls up the bottom plate 7 becomes larger than when the support shaft 14 is located at the second position. Here, the state in which the switching lever 24 and the support shaft 14 are located at the first position and the urging force of the tension spring 12 is large is for the recording material S that is heavy due to its large density or large size. The state in which the support shaft 14 is located at the second position and the urging force of the tension spring 12 is small is for the recording material S that is light in weight because of its small density or small size.

  In such a configuration, when the paper feed tray 5 is pushed into the mounting opening 4, the sliding portion 15 provided on the free end side of the arm 10 slides upward along the guide surface 11 a of the guide member 11. The arm 10 rotates upward with the support shaft 14 as a fulcrum, and accordingly, an urging force in a direction to stand on the bottom plate 7 acts via the tension spring 12.

  As a result, the bottom plate 7 rotates in a direction to stand up with the support shaft 6 as a fulcrum, and the uppermost recording material S on the bottom plate 7 is pressed against the lower outer peripheral surface of the paper feed roller 8. By rotating the sheet feeding roller 8 from this state, the uppermost recording material S on the bottom plate 7 is conveyed toward the image forming unit.

  At this time, when using a heavy recording material S, the operator positions the switching lever 24 at the first position and positions the support shaft 14 at the first position. As a result, the urging force of the tension spring 12 pulling up the bottom plate 7 is increased, and the pressing force of the recording material S against the sheet feeding roller 8 is optimized corresponding to the recording material S having a heavy weight. On the other hand, when the recording material S having a light weight is used, the operator positions the switching lever 24 at the second position and positions the support shaft 14 at the second position. As a result, the urging force by which the tension spring 12 pulls up the bottom plate 7 is reduced, and the pressing force of the recording material S against the sheet feeding roller 8 is optimized corresponding to the recording material S having a light weight.

  As described above, in this embodiment, the position adjusting mechanism 13 is operated by operating the switching lever 24 and the tensile force of the tension spring 12 is adjusted, so that the pressure contact force of the recording material S to the paper supply roller 8 is increased. Since the adjustment is made, the optimum pressure contact force can be obtained regardless of the type of the recording material S loaded on the bottom plate 7. Further, by operating the position adjusting mechanism 13 by operating the switching lever 24, it is not necessary to provide a drive source such as a motor for operating the position adjusting mechanism 13, and electrical control is not required. The number of points can be suppressed, and the cost can be reduced as a whole.

  Further, in the printer 1 in which the feeding direction of the sheet feeding tray 5 is the direction toward the downstream side of the feeding direction of the recording material S by the sheet feeding roller 8, the recording material S placed on the sheet feeding tray 5 and the sheet feeding roller 8. The pressure contact force can be adjusted.

  Further, the position adjustment mechanism 13 positions the support shaft 14 at a position set for each of a plurality of types of recording materials S, whereby the support shaft 14 can be positioned according to the recording material S with a simple operation. it can.

  Also, a plurality of arms 10 are provided, and the position adjusting mechanism 13 includes a base shaft 17 that is a synchronization unit that synchronizes the positioning operations of the support shafts 14 of the plurality of arms 10. The support shaft 14 of the arm 10 can be positioned at the same time, and the operation is simple.

  Further, since the switching lever 24 that is an operation member is single, for example, the structure is simplified and the cost can be reduced as compared with the case where the switching lever 24 is provided for each of the plurality of arms 10.

1 is a cross-sectional view illustrating a schematic structure of an entire printer according to an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a state where a paper feed tray is pulled out. It is a top view which shows a press-contact force adjustment mechanism. It is a perspective view which expands and shows a part of press-contact force adjustment mechanism. It is a perspective view which shows the press-contact force adjustment mechanism in the state where the switching lever was located in the 1st position. It is a perspective view which shows the press-contact force adjustment mechanism in the state where the switching lever was located in the 2nd position. It is sectional drawing which shows the whole printer of the state in which the spindle was located in the 2nd position.

Explanation of symbols

1 Printer 2 Printer body (device body)
DESCRIPTION OF SYMBOLS 3 Paper feeder 4 Mounting slot 5 Paper feed tray 7 Bottom plate 8 Paper feed roller 10 Arm 11 Guide member 11a Guide surface 12 Tension spring (biasing body)
13 Position adjustment mechanism 14 Support shaft 17 Base shaft (synchronizing means)
24 Switching lever (operating member)
S Recording material

Claims (6)

A paper feed tray that is detachably mounted in a mounting port formed in the apparatus body;
A bottom plate on which a recording material is stacked and mounted on a bottom portion in the paper feed tray,
A sheet feeding roller that is disposed above the bottom plate of the sheet feeding tray mounted in the loading slot and is in contact with a recording material placed on the bottom plate and is driven to rotate in the feeding direction of the recording material; ,
An arm attached to the paper feed tray so as to be rotatable in a vertical direction with a support shaft as a fulcrum;
A guide member fixed to the apparatus body having a guide surface that is inclined upward and gradually slidably guides toward the inner side of the mounting opening;
One end is connected to the free end side of the bottom plate, and the other end is connected to the arm, and the recording material placed on the bottom plate is brought into pressure contact with the paper feeding roller by applying a biasing force in a direction standing on the bottom plate. A biasing body;
A position adjusting mechanism for holding the support shaft of the arm movably in a direction perpendicular to the axial direction and positioning the support shaft;
An operating member for operating the position adjusting mechanism by an operator's operation;
A paper feeding device comprising:   The sheet feeding device according to claim 1, wherein the position adjusting mechanism positions the support shaft at a position set for each of a plurality of types of recording materials. A plurality of the arms are provided,
The sheet feeding device according to claim 1, wherein the position adjustment mechanism includes a synchronization unit that synchronizes positioning operations of the support shafts of the plurality of arms.   The sheet feeding device according to claim 3, wherein the operation member is single.   5. The sheet feeding device according to claim 1, wherein a drawing direction of the sheet feeding tray is a direction toward a downstream side of a recording material feeding direction by the sheet feeding roller. A paper feeding device according to any one of claims 1 to 5,
An image forming unit that performs an image forming operation on the recording material fed by the paper feeding device;
An image forming apparatus comprising:

Images