JP3281649B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder, and more particularly, to a paper feeder.
The present invention relates to an optimum sheet feeding device used for supplying a transfer material to an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art FIG. 9 is a front view showing a schematic configuration of a conventional sheet feeding device.

A large number of sheets 2 (plain paper, etc.) are placed on a flat plate-shaped bottom plate 1 whose rear end is rotatably attached to a fulcrum, and a pair of paper feeders is placed on the top end thereof. The roller 3 is in contact. A lower end of an "L" -shaped lever 4 is in contact with the bottom of the bottom plate 1, and a spring 5 for rotating the lever 4 in a counterclockwise direction is engaged with the upper end.

In this configuration, when the sheet feeding roller 3 rotates, an extruding force is generated between the sheet 2 and the uppermost sheet by friction, and the uppermost sheet is fed to a transport path (not shown). . As the sheet feeding progresses and the thickness of the sheet 2 becomes thinner, the lever 4 urged by the spring 5 rotates counterclockwise in the drawing to push up the leading end of the bottom plate 1, and the leading end of the sheet 2 is constantly moved. Is pressed by the paper feed roller 3.

[0005]

However, in the above-mentioned prior art, a spring is used to constantly press the sheet against the sheet feeding roller, and the sheet feeding roller 3 is always used even when the sheet is not passing. Is given an urging force. For this reason, there is a problem that paper dust adheres to the paper feed roller and further causes roller deformation.

Further, even when the sheet starts to be fed by the paper feed roller, the load on the drive system is increased because the bottom plate is kept urged, and a load is imposed on the drive system.

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeder which has been made in view of the above-mentioned prior art, and which can reduce an adverse effect on a paper feed roller and a load on a drive system. .

[0008]

In order to achieve the above object, the present invention provides a bottom plate on which several sheets are stacked,
An elevating mechanism for elevating the bottom plate with respect to the paper feed roller,
In a paper feeder having a drive source for driving the lifting mechanism, a size for detecting a size of a sheet on the bottom plate is provided.
Detecting means for detecting the rise of the movable end of the bottom plate;
Cushioning material for buffering the collision between the
A moving device for moving the cushioning material in the length direction of the sheet
Structure and the size detected by the size detection means.
Controlling the movement of the cushioning material by the moving mechanism.
And control means .

In this case, the control means includes a
The larger the size, the more loosely the pivot point of the bottom plate
Move the opponent.

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

According to the above-mentioned means, the sheet feeding roller and the sheet
Support the cushioning material provided to cushion the impact due to the collision.
Movement mechanism linked to the size detected by the noise detection means
By moving the sheet more in the length direction,
Increase the load moment and the load moment by the cushioning material.
Can be reduced .

[0016] The control means may control that the size of the sheet is large.
Move the cushioning material closer to the pivot point of the bottom plate
By doing so, the urging force applied by the cushioning material
Load moment.

[0017]

[0018]

[0019]

[0020]

[0021]

FIG. 1 is a front view showing a first embodiment of a sheet feeding apparatus according to the present invention, and FIG. 2 is a side view showing a driving section of the embodiment of FIG. In FIG. 1, the same reference numerals are used for the same components as those shown in FIG. 9, and thus redundant description will be omitted below.

An upper end of an arm 6 is in contact with a lower surface of the bottom plate 1, and a lower end of the arm 6 is attached to a rotating shaft 7. As shown in FIG. 2, a torque limiter 8 as a conversion means is attached to an end of the rotating shaft 7, and a shaft 9 is arranged in parallel with the rotating shaft 7 via the torque limiter 8. A drive source 10 (for example, a motor)
Is attached.

In this embodiment, when the drive source 10 rotates clockwise, the rotation is transmitted to the torque limiter 8 via the shaft 9, and the rotation is transmitted to the rotary shaft 7 via the torque limiter 8. . Since the arm 6 is attached to the rotation shaft 7, the rotation of the rotation shaft 7 rotates the arm 6, pushing up the lower surface of the bottom plate 1, and pressing the front portion of the sheet 2 against the lower surface of the sheet feeding roller 3. That is, the driving source 10
And the torque limiter 8 corresponds to the conventional spring 5,
The bottom plate 1 is pushed up by the rotation of the drive source 10. With such a configuration, since the torque is converted by the torque limiter 8 into the urging force of the bottom plate 1, the urging / releasing mechanism can be simplified and the responsiveness can be increased.

In the configuration of FIG. 2, the drive source 10 is not provided independently, but the output of the drive source of the copying machine to which the present invention is applied is used. It may be made to come and go (on / off). By doing so, a dedicated driving source for driving the arm 6 is not required, and the configuration can be simplified and the cost can be reduced. Further, when there are a plurality of paper feed trays, it is possible to release the bottom plate urging in another tray while feeding paper in one tray and supply sheets.

FIG. 3 is a block diagram showing a second embodiment of the present invention. In FIG. 3, the same reference numerals are used for the same components as those in FIGS. 1 and 2, and thus the duplicate description will be omitted.

In the present embodiment, a sensor 11 as a detecting means installed on the exit side of the paper feed roller 3 with respect to the configuration of FIG.
And a control unit 12 that controls the drive source 10 based on a detection signal of the sensor 11.

In this embodiment, the driving of the drive source 10 is started at the start of sheet feeding, and the sheet feeding roller 3 is driven to rotate to start feeding the uppermost sheet of the sheet 2. In this process, the sensor 11 detects the start of sheet feeding, and sends a detection signal to the control unit 12. The control unit 12 stops the driving source 10 that is being driven based on a detection signal from the sensor 11. Then, the driving source 10 is driven a predetermined time before the next sheet is fed, and a sheet feeding pressure is generated.

FIG. 4 is a block diagram showing a third embodiment of the present invention. Note that, in this embodiment, the same reference numerals are used for the same components as those shown in FIG.

This embodiment is characterized in that, in addition to the configuration shown in FIG. 3, a size detecting means 13 is provided at the rear end of the bottom plate 1 and this detection signal is taken into the control unit 12.

In this embodiment, the size of the sheet 2 is detected by the size detecting means 13, and the cutoff time (power stop time) of the drive source 10 is adjusted according to the detected size. Although the command to stop the drive source 10 depends on the output of the sensor 11 as in the previous embodiment, in this embodiment, when the size is large, the sheet is
As the time to escape from the camera becomes longer, the cut-off time is made slower.

In the embodiment shown in FIG. 4, by detecting the length in the sheet feeding direction and adjusting the drive cutoff time, the sheet feeding pressure can be efficiently increased even in a multi-tray capable of supporting various sheet sizes. Can be depressurized, and the load on the drive system can be reduced.

FIG. 5 is a front view showing a fourth embodiment of the present invention. Also in the present embodiment, the same reference numerals are used for the same components as those in the above-mentioned embodiments, and thus the duplicate description will be omitted.

This embodiment is different from the embodiment of FIG.
A buffer material 14 is provided below the tip of the bottom plate 1, and the driving source 1 is provided.
Even when the bottom plate 1 falls due to the zero drive stop, the end of the bottom plate 1 can prevent vibration and noise from being caused by collision with the main body.

FIG. 6 is a front view showing a fifth embodiment of the present invention. Also in the present embodiment, the same reference numerals are used for the same components as those in the above-mentioned embodiments, and thus the duplicate description will be omitted.

This embodiment is different from the configuration of FIG.
There is a feature in that a spring 15 is provided as a cushioning material for pressing down the upper surface. With such a configuration, the bottom plate 1
When the sheet 2 and the paper feed roller 3 attempt to collide with each other when the drive source 10 is driven, the spring 15 reduces the lifting force of the bottom plate 1 to prevent the sheet 2 from violently colliding with the paper feed roller 3, The vibration and noise caused by the vibration can be prevented (FIG. 7).

In FIG. 6, instead of the spring 15, a member having elasticity such as rubber can be used.

FIG. 8 is a block diagram showing a sixth embodiment of the present invention. Also in the present embodiment, the same reference numerals are used for the same components as those in the above-mentioned embodiments, and thus the duplicate description will be omitted.

This embodiment is characterized in that the embodiment of FIG. 4 and the embodiment of FIG. 6 are combined, and a moving mechanism 16 for horizontally moving the spring 15 is provided. Moving mechanism 16
Is a rack 17 for horizontally moving the spring 15, a gear 18 meshing with the rack 17, a motor 19 having a rotating shaft serving as an axis of the gear 18, and turning on / off the motor 19 based on a detection signal of the size detecting means 13. It comprises each of the control means 20 for performing control.

In this embodiment, the position of the spring 15 with respect to the fulcrum 21 of the bottom plate 1 moves in the horizontal direction in the figure according to the size detected by the size detecting means 13. For example, sheet 2
When the size is large, the distance between the fulcrum 21 and the spring 15 is reduced, and when the size is small, the distance is increased. When the spring 15 is moved rightward in the drawing, the motor 19
Is rotated counterclockwise, and the rack 17 is
Is moved rightward in the figure.

As described above, the larger the size, the closer the spring 15 is to the fulcrum 21, so that the load moment due to the urging force decreases, and the increase in the load moment due to the increase in the seat load can be reduced.

[0041]

Since the present invention is constituted as described above, the following effects can be obtained.

In the paper feeder according to the first aspect, the size detection is performed.
The cushioning material is linked to the size detected by the
A moving mechanism is provided to move the sheet in the length direction.
Mitigates increase in load and increase in load moment due to cushioning material
can do.

In the paper feeder of the second aspect, the sheet
As the size increases, move the cushioning material to the swing support side of the bottom plate.
Movement, the seat load increases and the cushioning material
Load moment due to biasing force can be reduced
You.

[0044]

[0045]

[0046]

[0047]

[0048]

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of a sheet feeding device according to the present invention.

FIG. 2 is a side view showing a driving unit of the embodiment of FIG.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the present invention.

FIG. 5 is a front view showing a fourth embodiment of the present invention.

FIG. 6 is a front view showing a fifth embodiment of the present invention.

FIG. 7 is a front view showing an operation state of the embodiment in FIG. 6;

FIG. 8 is a configuration diagram showing a sixth embodiment of the present invention.

FIG. 9 is a front view showing a schematic configuration of a conventional sheet feeding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bottom plate 2 Sheet 3 Paper feed roller 4 Lever 5 Spring 6 Arm 7 Rotation axis 8 Torque limiter 9 Axis 10 Drive source 11 Sensor 12 Control unit 13 Size detection means 14 Buffer material 15 Spring 16 Moving mechanism 17 Rack 18 Gear 19 Motor 20 Control Means 21 fulcrum

Claims (2)

(57) [Claims] And 1. A bottom plate a number of sheets are stacked, a lifting mechanism for raising and lowering the bottom plate relative to the paper feed roller, the paper feeding apparatus comprising a driving source for driving the elevating mechanism, the bottom plate Size detection means for detecting the size of the upper sheet
The sheet and the sheet feeder with respect to the rise of the movable end of the bottom plate.
A cushioning material for cushioning a collision with a roller, and a moving device for moving the cushioning material in a longitudinal direction of the sheet
And linked with the size detected by the size detection means,
Control means for controlling the movement of the cushioning material by the moving mechanism
Sheet feeding apparatus characterized by comprising a and. 2. The control device according to claim 1 , wherein the size of the sheet is
The larger the size, the more the cushioning material is moved to the pivot point of the bottom plate.
The paper feeding device according to claim 1, wherein the paper feeding device is moved.