JPH0986680A - Feeder bottom plate lifting device - Google Patents

Abstract

Kind Code: A1 Abstract: The deviation of the stop position of the bottom plate when moving the bottom plate of the paper feeding device to position the paper at the paper feeding position is reduced. A shaft 6 of an elevating member 5 is rotated together with an eccentric rotating piece 7 by an elevating motor 13, and a bottom plate 2 is pushed up by the eccentric rotating piece 7 and rotated around a fulcrum 2 to raise a free end side. The lift motor 13 is stopped by the detection of the sensor, and the bottom plate 3
When it stops rising, it does not stop immediately due to inertial force, so the lifting motor 13 is reversed and the bottom plate 3 is once lowered. Every few seconds thereafter, the voltage applied to the lifting motor 13 is lowered, the lifting motor 13 is rotated again so that the re-raising speed of the bottom plate 3 becomes slow, and the bottom plate 3 is lifted again. When the sensor is re-detected, the lift motor 13 is stopped again, and the re-elevation of the bottom plate 3 is stopped. Re-elevation at low speed causes a small inertial force, and the bottom plate 3 stops at a predetermined position almost accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom plate raising / lowering device for a sheet feeding device in which a bottom plate in a sheet feeding tray is moved up and down by a driving force of a motor in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, as a typical paper feeding device such as a copying machine or a printer, there is one in which a paper feeding tray on which papers to be used are stacked is detachably attached to an image forming apparatus body such as a copying machine. As one of such paper feeding devices, a bottom plate having a rotation fulcrum in a direction perpendicular to the paper conveyance direction and a lifting member having a rotation fulcrum in a direction perpendicular to the paper conveyance direction for elevating the bottom plate are provided in the paper feed tray. However, there has been proposed a sheet feeding device that controls the uppermost sheet to be positioned at the best sheet feeding position by raising the bottom plate according to the amount of stacked sheets. In this technology, as a control to correct the misalignment due to the delay in the response of the lifting motor and to position the uppermost paper at the best paper feeding position, the bottom plate is first raised to detect the bottom plate position, and then the bottom plate is detected. Drive control that lowers and then raises again.

[0003]

However, the above-described bottom plate lifting device of the sheet feeding device can correct only a part of the positional deviation due to the inertial force generated by the weight of the stacked sheets, and the position correcting effect is not obtained. There is a problem of being few.

In view of the above conventional problems, it is an object of the present invention to provide a bottom plate raising / lowering device for a sheet feeding device which is excellent in correcting the position of the sheet feeding position.

[0005]

According to a first aspect of the present invention, there is provided a bottom plate elevating device for a sheet feeding device, wherein a paper feeding tray having a bottom plate on which a sheet is placed is detachably attached to an image forming apparatus main body. An elevating member for the bottom plate, an elevating motor for driving the elevating member, a bottom plate position detecting means for detecting the position of the bottom plate in a paper-feedable state, and an operation for raising the bottom plate to detect the bottom plate position, and then temporarily In a bottom plate elevating device of a sheet feeding device having a control unit for lowering the bottom plate and then raising it again, the input applied voltage to the elevating motor is lowered when the bottom plate is raised again.

In the apparatus according to the first aspect, the bottom plate is first driven in the ascending direction by the lifting motor, the bottom plate is stopped after detecting the bottom plate ascending position, and then the bottom plate is driven in the descending direction, and then the re-elevation is performed. However, the re-raising speed of the bottom plate is made slower than the initial rising speed of the bottom plate by lowering the voltage applied to the lifting motor upon re-raising.

According to a second aspect of the present invention, there is provided a bottom plate elevating / lowering device for a sheet feeding device, wherein a paper feed tray having a bottom plate on which a sheet is placed is detachably attached to an image forming apparatus main body, and an elevating / lowering member for the bottom plate, An elevating motor for driving the elevating member, bottom plate position detecting means for detecting the position of the bottom plate in a paper feedable state, and raising the bottom plate to detect the bottom plate position,
In a bottom plate lifting device of a sheet feeding device having a control unit for lowering the bottom plate once and then raising it again, an electromagnetic clutch and a torque limiter interlocking with a gear of the electromagnetic clutch are provided on an output shaft of the lifting motor. It is characterized by

According to the second aspect of the present invention, an electromagnetic clutch on the output shaft of the lifting motor and a torque limiter interlocking with the gear of the electromagnetic clutch are provided, and the clutch is turned on to increase the load when the bottom plate is raised again. Thereby, the re-raising speed of the bottom plate is made slower than the initial rising speed of the bottom plate.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a bottom plate lifting device for a sheet feeding device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a first embodiment of a bottom plate elevating / lowering device of a sheet feeding device according to the present invention, and FIG. 2 is a perspective view of the relevant part. Sliding rails 19 and 20 that make the paper feed tray 1 detachable are provided on the left and right side surfaces of the rectangular parallelepiped paper feed tray 1 in the drawing. Paper tray 1
A bottom plate 3 is provided at the bottom of the paper, and the bottom plate 3 is pivotally supported on the paper feed tray 1 by a fulcrum 2 so as to be rotatable about a rotary shaft extending in a direction orthogonal to the paper transport direction.

Reference numeral 5 in the drawing denotes an elevating member, which is provided below the bottom plate 3 and has a shaft 6, an eccentric rotating piece 7 fixed near one end of the shaft 6, and a radial direction near the other end of the shaft 6. And two engaging projections 8 attached by being attached. Shaft 6 of lifting member 5
When the eccentric rotary piece 7 is rotated about its central axis, the eccentric rotary piece 7 also rotates around the central axis of the shaft 6, and the eccentric rotary piece 7 moves to the bottom plate 3.
The bottom plate 3 is lifted upward by contacting the lower surface of the bottom plate.

As shown in FIG. 2, the drive unit 14 of the bottom plate lifting device includes a lifting motor 13, a worm gear 12 attached to the output shaft of the lifting motor 13, a wheel gear 11 that meshes with the worm gear 12, and a wheel gear. The spur gear 10 meshes with the gear 11, and the coupling 9 is attached to the rotary shaft of the spur gear 10. The coupling 9 has a cylindrical shape and has four notches extending from the free end in parallel with the rotation axis. The engagement protrusions 8 of the shaft 6 of the elevating member 5 are fitted into the notches of the coupling 9. Then, the drive unit 14 rotationally drives the shaft 6 of the elevating member 5.

Next, the operation of the first embodiment of the present invention will be described. FIG. 3 is a flowchart showing the operation of the bottom plate elevating device of the sheet feeding device according to the first embodiment of the present invention. When the paper feed tray 1 is attached to the apparatus main body (step 1), a sensor (not shown) detects the paper feed tray 1 and sends a positive output voltage to the lifting motor 13 to drive the lifting motor 13 to rotate in the forward direction ( Step 2). The elevating motor 13 rotationally drives the shaft 6 of the elevating member 5 in the positive direction to rotate the eccentric rotating piece 7 around the shaft 6. Then, the eccentric rotating piece 7 pushes up the bottom plate 2 from below, and the bottom plate 3 rotates about the fulcrum 2 to rotate the bottom plate 3.
Rises (step 3).

It is judged whether or not the bottom plate position detection sensor 21 detects the bottom plate 3 (step 4), and if not detected, the positive output voltage is continuously applied to the lifting motor 13 (step 2), but the bottom plate position detection sensor is detected. When 21 detects the bottom plate 3, the elevating motor 13 is stopped without applying an output voltage to the elevating motor 13 (step 5). That is, when the bottom plate position detection sensor 21 detects the bottom plate, the bottom plate 3 tries to stop, but the bottom plate 3 does not try to stop immediately due to its inertial force, and then the position shifts.

Therefore, after the lifting motor 13 is stopped,
The lifting motor 13 is reversed (step 6). Then
The bottom plate 3 rotates backward about the fulcrum 2 and descends. In this state, the system stands by for a few seconds (step 7), and then the elevating motor 13 is normally rotated again to raise the bottom plate 3 (step 9). At this time, the applied voltage input to the lifting motor 13 is lowered (step 8), and the speed of re-raising of the bottom plate 3 (step 10) is made slower than the initial rising speed of the bottom plate 3. Then, when the bottom plate position detection sensor 21 detects the bottom plate 3 (step 11), the lift motor 13 is stopped. That is, since it re-rises and stops at a low speed, the inertial force of the bottom plate 3 becomes small,
The deviation of the stop position can be reduced.

FIG. 4 is a perspective view of an essential part of a bottom plate elevating device of a sheet feeding device according to the second embodiment of the present invention. The same parts as those in the previous embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

Output shaft 1 of lifting motor 13 of this embodiment
8, an electromagnetic clutch 22 is attached, and a gear 15 is attached to the electromagnetic clutch 22. Further, a rotary shaft extending parallel to the output shaft 18 of the lifting motor 13 is pivotally supported by the drive unit 14, a gear 16 is attached to the rotary shaft, and the gear 15 is meshed with the gear 15. A torque limiter 17 is provided integrally with the gear 16.

Next, the operation of the second embodiment will be described. FIG. 5 is a flow chart showing the operation of the bottom plate lifting device of the paper feeding device of the second embodiment of the present invention. The operation from the mounting of the paper feed tray 1 (step 1) to the standby after the reverse rotation of the lifting motor 13 (step 7) is the same as the operation shown in the flowchart of FIG. 3 showing the operation of the first embodiment. The description is omitted. After allowing the lifting motor 13 to stand by for several seconds, the lifting motor 13 is normally rotated again to move the bottom plate 2
Before re-raising (steps 9 and 10), the electromagnetic clutch 22 is turned on and the gear 15 is connected to the output shaft 18 (step 8). Then, the gear 16 that meshes with the gear 15
Since the torque limiter 17 integrated with the bottom plate 3 acts as a load, the re-raising speed of the bottom plate 3 becomes slower than the initial rising speed of the bottom plate 3 and re-raises at a low speed.
Stops when the bottom plate 3 is detected by step 1 (step 1
1, 12), the inertial force of the bottom plate 3 becomes small, and the positional deviation becomes small as in the previous embodiment. In this embodiment, the re-raising speed can be easily changed in a wider range by changing the torque limiter 13.

[0019]

According to the bottom plate elevating device of the sheet feeding device of the first aspect, the input applied voltage of the elevating motor is lowered at the time of re-elevation, so that the re-elevation speed of the bottom plate is made slower than the initial elevation speed of the bottom plate. Therefore, it is possible to reduce the inertial force of the bottom plate and reduce the deviation of the stop position.

According to the bottom plate lifting device of the sheet feeding device of the second aspect, since the electromagnetic clutch on the output shaft of the lifting motor and the torque limiter interlocked with the gear of this electromagnetic clutch are provided, the bottom plate is lifted again. By increasing the load by sometimes turning on the clutch, the re-raising speed of the bottom plate can be made slower than the initial rising speed of the bottom plate, and the inertial force of the bottom plate can be reduced to reduce the deviation of the stop position. There is an effect that.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of a bottom plate elevating device for a sheet feeding device according to the present invention.

FIG. 2 is a perspective view of the main part.

FIG. 3 is a flowchart showing the operation of the embodiment shown in FIGS.

FIG. 4 is a perspective view of a main part of a bottom plate lifting device of a sheet feeding device according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the embodiment shown in FIG.

[Explanation of symbols]

 1 Paper Feed Tray 2 Support Point 3 Bottom Plate 4 Paper 5 Elevating Member 6 Shaft 7 Eccentric Rotating Piece 8 Engaging Protrusion 9 Coupling 10 Spur Gear 11 Wheel Gear 12 Worm Gear 13 Elevating Motor 14 Drive Unit 15, 16 Gear 17 Torque Limiter 18 Output Shaft 19, 20 Sliding Rail 21 Bottom Plate Position Detection Sensor 22 Electromagnetic Clutch

Claims (2)

[Claims] 1. A paper feed tray having a bottom plate on which a sheet is placed is detachably attached to an image forming apparatus main body, and an elevating member for the bottom plate, an elevating motor for driving the elevating member, and a feedable state. Bottom plate position detecting means for detecting the position of the bottom plate, and after detecting the bottom plate position by raising the bottom plate,
A bottom plate elevating device for a sheet feeding device having a control unit for lowering the bottom plate and then raising it again, characterized in that the input applied voltage to the elevating motor is lowered when the bottom plate is raised again. Bottom plate lifting device. 2. A paper feed tray having a bottom plate on which a sheet is placed is detachably attached to the main body of the image forming apparatus, an elevating member for the bottom plate, an elevating motor for driving the elevating member, and a paper feedable state. Bottom plate position detecting means for detecting the position of the bottom plate, and after detecting the bottom plate position by raising the bottom plate,
In a bottom plate lifting device of a sheet feeding device having a control unit for lowering the bottom plate once and then raising it again, an electromagnetic clutch and a torque limiter interlocking with a gear of the electromagnetic clutch are provided on an output shaft of the lifting motor. A bottom plate lifting device for a sheet feeding device, which is characterized in that