JP4298607B2 - Paper feeder - Google Patents

Description

  The present invention relates to a sheet feeding device that is provided in an image forming apparatus such as a printer, a fax machine, and a copying machine, and stores a plurality of sheets and feeds them one by one toward an image forming unit.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique that includes a pressing spring and an auxiliary spring that press a bottom plate toward a sheet feeding roller in a sheet feeding device.

  Patent Document 2 discloses a technique in which a spring is connected to a pressing member that supports a bottom plate so as to be movable up and down, and the length of the spring is adjusted by a motor.

JP-A-9-194050 JP-A-8-192926

  However, in the prior art described in Patent Document 1, since the auxiliary spring is fixed to the bottom plate, the urging force of the auxiliary spring cannot be arbitrarily changed, and the paper feed roller according to characteristics such as the type of paper and the paper thickness. There is a problem that it is difficult to adjust the paper feed pressure with respect to.

  Further, the conventional technique described in Patent Document 2 has a problem that the configuration is complicated because the length of the spring is adjusted by driving the motor.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding device that can arbitrarily change the sheet feeding pressure with respect to the sheet feeding roller with a simple configuration.

In order to solve the above-mentioned problem, the invention described in claim 1 includes a bottom plate that is supported in the paper feed tray so as to be movable up and down and stacks a plurality of paper bundles, and a paper feed provided above the bottom plate. A sheet feeding device that includes a roller, a pressing spring that urges the bottom plate toward the sheet feeding roller, and an auxiliary spring, and that feeds sheets one by one by bringing the sheet bundle loaded on the bottom plate into contact with the sheet feeding roller. The bottom plate is provided with a variable portion for changing the urging force of the auxiliary spring. The variable portion is supported on the bottom plate so that one end of the variable spring can be rotated and fixed to the auxiliary spring. An operating lever, and the other end side of the pressing member is moved up and down by sliding the operating lever to change the length of the auxiliary spring .

The invention described in claim 2 is characterized in that, in the invention described in claim 1, the variable section is provided with a display section for displaying the magnitude of the urging force of the auxiliary spring .

The invention described in claim 3 is the invention described in claim 1 or 2, wherein the variable portion is formed with a plurality of engaging portions along a sliding direction of the operation lever, and the operation lever Comprises an engaged portion that engages with the engaging portion, and the urging force of the auxiliary spring is changed stepwise by sliding the operation lever and engaging the engaged portion with each engaging portion. characterized in that it.

The invention described in claim 4 is, in the invention according to any one of claims 1 to 3, in the variable portion, characterized in that the cover to shield the operating lever is provided.

  According to the present invention, since the variable portion for changing the biasing force of the auxiliary spring is provided on the bottom plate, the feeding pressure to the paper feeding roller can be changed with a simple configuration by changing the biasing force of the auxiliary spring by the variable portion. It can be changed arbitrarily.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The first embodiment will be described with reference to FIGS. 1 is a cross-sectional view showing a paper feeding device according to the first embodiment, FIG. 2 is a perspective view of the paper feeding device shown in FIG. 1, and FIG. 3 is a diagram showing a main part of the paper feeding device shown in FIG. FIG. 4 is a diagram showing a main part of the sheet feeding device shown in FIG. 1, a perspective view showing a state in which the operation lever is returned, and FIG. 5 shows driving of the auxiliary spring. FIG. 6 is a cross-sectional view showing a state in which the auxiliary spring protrudes from the housing portion, and FIG. 6 is a view showing driving of the auxiliary spring, and a cross-sectional view showing a state in which the auxiliary spring is housed in the housing portion.

  The paper feeding device 1 is disposed below the image forming apparatus 100 and includes a box-shaped paper feeding tray 3. The sheet feeding device 1 is provided with a bottom plate 5 on which a plurality of sheet bundles are stacked. The bottom plate 5 is supported so as to be movable up and down around a rotation fulcrum 7 provided on one end side. A paper feed roller 9 is provided above the bottom plate 5 on the other end side of the paper feed tray 3, and the paper feed roller 9 is accommodated in the unit 11. The paper feed roller 9 is rotated by the rotation of the roller shaft in response to the drive from the drive source.

  A pressing spring 13 that urges the bottom plate 5 toward the paper feed roller 9 is provided at the other end of the bottom plate 5. The lower end 13 a of the pressing spring 13 is fixed to the bottom plate 5, and the upper end 13 b is fixed to the pressure arm 15. A substantially arc-shaped sliding portion 17 is provided below the pressing arm 15, and the pressing arm 15 moves along the arc shape of the sliding portion 17. When the paper feed tray 3 is stored, the pressure arm 15 moves upward along the arc shape of the sliding portion 17 and comes to a position indicated by A in FIG. At this time, since the bottom plate 5 is connected to the pressure arm 15 and the pressing spring 13, the bottom plate 5 rotates about the rotation fulcrum 7 in accordance with the movement of the pressure arm 15. In this way, the bottom plate 5 is urged in the direction of the paper feed roller 9 by the pressing spring 13 connected to the pressure arm 15 so that an appropriate paper feed pressure for paper feed can be obtained.

  When paper is set in the paper feed tray 3, the extension amount of the press spring 13 changes according to the stack amount of the paper to be set (if the load amount is large, the extension amount of the press spring 13 becomes large). When the stacking amount is small, the extension amount of the pressing spring 13 is small.) The sheet feeding pressure applied to the sheet feeding roller 9 also changes. If the sheet feeding pressure is too strong, double feeding is likely to occur, and if the sheet feeding pressure is weak, non-feeding is likely to occur. Therefore, an auxiliary spring 19 is provided on the bottom plate 5 together with the pressing spring 13 in order to obtain a paper feeding pressure corresponding to the paper stacking amount, and an appropriate paper feeding pressure is obtained by adjusting the auxiliary spring 19.

  Next, the configuration of the auxiliary spring 19 will be described. The bottom plate 5 is formed with an accommodating portion 21 of a substantially cylindrical auxiliary spring 19, and the accommodating portion 21 is formed to protrude upward from the bottom plate 5. The auxiliary spring 19 can be accommodated in the accommodating portion 21. Further, a locking portion 23 is formed at the upper end in the accommodating portion 21, and the upper end of the auxiliary spring 19 is locked to the locking portion 23.

  The bottom plate 5 is provided with a variable portion 25 for operating the auxiliary spring 19 so as to be freely inserted into and retracted from the accommodating portion 21. The variable portion 25 includes a presser member 27 whose one end is rotatably supported on the bottom plate 5, and an operation lever 29 for operating the presser member 27. The lower end of the auxiliary spring 19 is attached to the other end of the presser member 27. It has been. The operation lever 29 is movably provided along the bottom plate 5. When the operation lever 29 is moved in the direction in which the auxiliary spring 19 is located, the operation lever 29 moves toward the storage portion 21 side of the auxiliary spring 19. One end side of the pressing member 27 is gradually rotated upward so that the length of the auxiliary spring 19 is shortened. On the other hand, when the operation lever 29 is slid in a direction away from the storage portion 21 of the auxiliary spring 19, the presser member 27 rotates downward about the fulcrum, and the auxiliary spring 19 fixed to the end of the presser member 27 becomes longer. It is supposed to be.

  Further, the variable portion 25 is provided with a display portion 31 so that the position of the auxiliary spring 19 can be seen. In this embodiment, the display portion 31 is labeled “OFF” on the operation lever 29 as shown in FIG. As shown in FIG. 4, the support plate 32 on the lower side of the operation lever 29 is labeled “ON”.

  Next, operations and effects according to the present embodiment will be described. In order to weaken the paper feed pressure for the paper feed roller 9, the knob 30 of the operation lever 29 is slid in a direction away from the storage portion 21 of the auxiliary spring 19. When the operation lever 29 is slid, the presser member 27 rotates upward about the fulcrum. When the presser member 27 is rotated upward, the auxiliary spring 19 moves upward in conjunction with the presser member 27, the auxiliary spring 19 is shortened, and the urging force is gradually weakened. When the operation lever 29 is completely pulled, the presser member 27 becomes substantially horizontal and the auxiliary spring 19 is stored in the storage portion 21.

  In order to increase the paper feed pressure for the paper feed roller 9, the knob 30 of the operation lever 29 is slid in a direction to approach the storage portion 21 side of the auxiliary spring 19. As the operating lever 29 slides, the presser member 27 rotates downward about the fulcrum. When the pressing member 27 rotates downward, the auxiliary spring 19 moves in a direction away from the storage portion 21 in conjunction with the pressing member 27, and the auxiliary spring 19 becomes gradually longer. When the operation lever 29 is completely returned, the biasing force of the auxiliary spring 19 is maximized.

  As described above, in the present embodiment, the urging force of the auxiliary spring 19 can be freely changed, so that the sheet feeding pressure can be freely set by the user's judgment according to the sheet characteristics such as the sheet quality and the sheet thickness. .

  Further, when the operation lever 29 is slid, the “ON” and “OFF” display portions 31 displayed on the support lever 32 on and below the operation lever 29 are recognized, so that the state of the auxiliary spring 19 can be immediately changed. It is easy to grasp and operability is good.

  Since the upper portion of the auxiliary spring 19 is inserted into the storage portion 21, the auxiliary spring 19 is less likely to sway from side to side, and a sufficient urging force can be obtained to push the bottom plate 5 upward.

  Next, other embodiments will be described. In the description, parts having the same functions and effects as those described above are denoted by the same reference numerals, and detailed description thereof is omitted. 7 and 8 show a second embodiment of the present invention. In the second embodiment, the paper size is given to the surface of the bottom plate 5 as the display unit 31. In the present embodiment, “A4” is indicated at the position where the operation lever 29 is pulled to the maximum, and “A3” is indicated at the position where the operation lever 29 is returned to the maximum. In this way, by indicating the standard paper size on the bottom plate 5, mistakes in operation can be reduced.

  9 and 10 show a third embodiment of the present invention. In the third embodiment, as the display unit 31, a plurality of marks are attached to the bottom plate 5 along the sliding direction of the operation lever 29. Thus, by attaching a plurality of marks, it becomes easy to finely adjust the auxiliary spring 19.

  11 and 12 show a fourth embodiment of the present invention. In the fourth embodiment, a plurality of concave engaging portions 33 are formed on the bottom plate side along the sliding direction of the operating lever 29, and the operating lever 29 is convex and elastic to engage with the engaging portion 33. A deformable engaged portion 35 is provided. When the operation lever 29 is slid, the urging force of the auxiliary spring 19 is changed stepwise by the engaged portions 35 engaging the respective engaging portions 33. The number of the engaging portions 33 may be any number, and by increasing the number of the engaging portions 33, further fine adjustment of the urging force of the auxiliary spring 19 can be performed. Further, the position of the operation lever 29 can be predicted from the sliding sound and the sliding resistance when the engaging portion 33 and the engaged portion 35 are engaged during the sliding operation of the operating lever 29.

  FIG. 13 shows a fifth embodiment of the present invention, in which the drawing extracted by a one-dot chain line in the drawing is an enlarged plan view showing a knob portion of the operation lever. In the fifth embodiment, the tip of the knob 30 of the operation lever 29 is tapered, and the tapered portion of the knob 30 is positioned at the mark provided along the sliding direction of the operation lever 29. Thus, by providing a taper index on the knob 30, the current position of the operation lever 29 can be accurately grasped, and setting errors can be prevented.

  FIG. 14 shows a sixth embodiment of the present invention. In the present embodiment, a cover 37 that shields the operation lever 29 is provided. The cover 37 is sized to cover the movement range of the knob 30 of the operation lever 29. The cover 37 is provided with a claw 39 for fixing to the bottom plate 5. Thus, since the operation lever 29 can be shielded by the cover 37, the operation of the operation lever 29 due to mischief can be prevented.

In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible in the range which does not deviate from the summary.
In the above-described fourth embodiment, the concave engaging portion 33 is formed on the bottom plate 5 side, and the convex engaged portion 35 is formed on the operation lever 29. However, the bottom plate 5 side is formed with the convex engaging portion. 33, the concave engaged portion 35 may be formed on the operation lever 29.

It is sectional drawing which shows the structure of the paper feeding apparatus which concerns on 1st Embodiment. FIG. 2 is a perspective view of the sheet feeding device illustrated in FIG. 1. It is a figure which shows the principal part of the paper feeder shown in FIG. 1, and is a perspective view which shows the state which pulled the operation lever. It is a figure which shows the principal part of the paper feeder shown in FIG. 1, and is a perspective view which shows the state which returned the operation lever. It is a figure which shows the drive mechanism of an auxiliary spring, and is sectional drawing which shows the state which the auxiliary spring protruded from the accommodating part. It is a figure which shows the drive mechanism of an auxiliary spring, and is sectional drawing which shows the state in which the auxiliary spring was accommodated in the accommodating part. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 2nd Embodiment, and is a perspective view which shows the state which returned the operation lever. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 2nd Embodiment, and is a perspective view which shows the state which pulled the operating lever. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 3rd Embodiment, and is a top view which shows the state which has an operation lever in a predetermined scale position. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 3rd Embodiment, and is a top view which shows the state which moved the operation lever to the position shifted | deviated from the predetermined | prescribed scale position. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 4th Embodiment, and is a top view which shows the state which has an operation lever in a predetermined scale position. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 4th Embodiment, and is a top view which shows the state which moved the operation lever to the position shifted | deviated from the predetermined | prescribed scale position. It is a perspective view which shows the drive mechanism of the auxiliary spring which concerns on 5th Embodiment, The figure extracted and shown with the dashed-dotted line in the figure is a top view which expands and shows the knob part of an operation lever. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 6th Embodiment, and is a perspective view which shows the state which covered the operation lever. It is a figure which shows the drive mechanism of the auxiliary spring which concerns on 6th Embodiment, and is a perspective view which shows the state which removed the cover from the operation lever.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper feeder 5 Bottom plate 9 Paper feed roller 13 Pressing spring 19 Auxiliary spring 21 Storage part 25 Variable part 27 Holding member 29 Operation lever 31 Display part 33 Engagement part 35 Engagement part 37 Cover

Claims (4)

A bottom plate for stacking a plurality of sheet bundles are vertically movable supported on the paper feed tray, a paper feed roller disposed above the bottom plate, and the pressing spring for urging the bottom plate to the paper feed roller an auxiliary spring, a sheet bundle that is stacked on the bottom plate a sheet feeding apparatus for feeding sheets one by one is brought into contact with the feed roller, wherein the bottom plate to change the urging force of the auxiliary spring A variable portion is provided , the variable portion includes a holding member having one end pivotably supported on the bottom plate and the other end fixed to an auxiliary spring, and a slidable operation lever. A sheet feeding device , wherein the other end side of the pressing member is moved up and down to change the length of the auxiliary spring . The sheet feeding device according to claim 1, wherein the variable unit is provided with a display unit that displays a magnitude of a biasing force of the auxiliary spring . The variable portion is formed with a plurality of engaging portions along the sliding direction of the operating lever. The operating lever includes an engaged portion that engages with the engaging portion, and the operating lever slides. 3. The sheet feeding device according to claim 1 , wherein the urging force of the auxiliary spring is changed stepwise by the engagement of the engaged portions with the respective engaging portions . Sheet feeding apparatus according to any one of claims 1 to 3 to the variable portion, characterized in that the cover to shield the operating lever is provided.

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