JPH05186123A - Paper sheet tray drive device - Google Patents

Abstract

PURPOSE:To improve the maximum loading amount of a tray with a simple structure, and prevent breakdown due to some failure at the time of lowering the tray. CONSTITUTION:The rotational force of a DC motor is transmitted to a warm gear 58, a warm wheel 57, a gear 56, so that a discharge sheet tray moves vertically. The warm wheel 57 can move in an axial direction, and a compression spring 63 is forced so as to press the warm wheel 57 in the direction of the gear 56 at all time. A recessed part 57a and a protruding part 56a is formed so as to be fitted to each other in the rotational direction of the worm wheel 57 and the gear 56, and so as to be disengaged in an axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper tray driving device used in an image forming apparatus such as a copying machine.

[0002]

2. Description of the Related Art Generally, a paper tray driving device used in an image forming apparatus such as a copying machine is constructed such that a tray for discharging a bundle of paper sheets is vertically movable. It is disclosed in Japanese Patent Laid-Open No. 63-310459 and Japanese Patent Laid-Open No. 2-38259.

FIG. 9 shows a general sheet stacking device.
The timing pulleys 50, 51 are vertically arranged along the moving direction of the paper ejection tray 3,
A timing belt 52 is wound around 51. The side plates of the paper discharge tray 3 are fixed to the timing belt 52, and when the timing belt 52 moves, the paper discharge tray 3 moves in the vertical direction via the guide rollers 22. Therefore, by detecting the uppermost sheet on the tray 3, it is possible to control so that the uppermost sheet on the tray 3 is always at a fixed position.

The gear 54 is replaced by the timing pulley 50.
It is fixed coaxially with and is rotated by a drive mechanism below the gear 55. The DC motor 62, which is a drive source, is fixed such that the rotating shaft is in the vertical direction, and the timing pulley 61 is fixed to the rotating shaft. The timing belt 60 is wound around the timing pulley 61 and the timing pulley 59, and the primary deceleration of the DC motor 62 is performed. The worm gear 58 is fixed coaxially with the timing pulley 61, meshes with the worm wheel 57, performs secondary deceleration, and converts the rotation axis from the vertical direction to 90 ° in the horizontal direction. Further, the gear 56 is fixed coaxially with the worm wheel 57, meshes with the idler gear 55, and the idler gear 55 meshes with the gear 54, whereby third deceleration is performed.

In such a structure, in the conventional sheet stacking apparatus, the bearing type one-way clutch is provided in the gear 54 coaxial with the timing pulley 50, that is, the portion to which the load is applied, and the sheet bundle on the sheet discharge tray 3 is maximized. When the loaded amount is exceeded, the clutch is disengaged and the transmission between the paper discharge tray 3 and its drive mechanism is cut off.

[0006]

However, in the above-described conventional sheet stacking apparatus, since the transmission between the sheet discharge tray 3 and its drive mechanism is shut off by the bearing type one-way clutch, the sheet is discharged by the allowable transmission torque of the one-way clutch. There is a problem that the maximum stacking amount of the sheet bundle on the paper tray 3 is determined and the allowable transmission torque of the one-way clutch is limited.

Further, a means for detecting that the maximum capacity on the sheet discharge tray 3 is reached is required, but if this sensor is provided at the lower limit position of the sheet discharge tray 3, the wiring becomes complicated. Further, the bearing type one-way clutch is expensive and inferior in reliability. Further, when the discharge tray 3 is lowered and is obstructed by an obstacle or the like, the one-way clutch does not operate.

In view of the above problems of the prior art, the present invention provides a paper tray drive device capable of improving the maximum loading capacity of the tray with a simple structure and preventing damage due to an abnormality when the tray is lowered. The purpose is to

[0009]

In order to achieve the above object, the first means is a vertical drive means for moving the paper tray in the vertical direction, and a motor for driving the paper tray in the vertical direction. In a paper tray drive device including a transmission mechanism that transmits the rotation of the motor in the vertical direction, the transmission mechanism is capable of meshing with a worm gear rotated by the motor and movable in the axial direction. A worm wheel, a gear coaxial with the worm wheel, and an urging means for urging the worm gear and the worm wheel so that they can mesh with each other. Possible dents and ridges are provided on the worm wheel and the gear.

The second means includes a detecting means for detecting the disengagement of the worm wheel and the gear in the first means, and the detecting means detects an abnormal lowering of the paper tray and an excessive load on the paper tray. It is characterized by

[0011]

In the first means, when the paper tray is lowered abnormally or the paper tray is overloaded, the axial load increases between the worm wheel and the gear. The worm gear and the worm wheel are disengaged from each other by resisting the urging force of the urging means. Therefore, it is possible to improve the maximum load capacity of the tray with a simple structure and prevent damage due to an abnormality when the tray is lowered.

According to the second means, it is possible to detect an abnormal lowering of the paper tray and excess loading on the paper tray by one detecting means, and this detecting means is provided at a position irrelevant to the position of the paper tray. Therefore, this abnormal state can be detected regardless of the position of the paper tray.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a main part of an embodiment of a paper tray drive device according to the present invention, and FIG. 2 is a worm gear 58 of FIG.
And FIG. 3 is a plan view showing a disengaged state of the worm wheel 57, FIG. 3 is an explanatory view showing the worm wheel 57 of FIGS. 1 and 2, and FIG. 4 is an explanatory view showing a gear 56 mounted coaxially with the worm wheel 57. 5 is the gear 56 of FIG.
It is a perspective view which shows the fitting convex part 56a of in detail.

The structure shown in FIGS. 1 and 2 shows the secondary and tertiary reduction mechanisms of the drive mechanism described in FIG.
FIG. 1A is a plan view and FIG. 1B is a side view. That is, in this secondary reduction mechanism, the DC motor 62 shown in FIG.
From the timing pulley 61, the timing belt 60, and the timing pulley 59, the rotational force is transmitted to the worm gear 58, the worm gear 58 rotates about the vertical axis, and the worm gear 58 meshes with the worm wheel 57. The secondary deceleration is performed and the rotation axis is converted by 90 ° from the vertical direction to the horizontal direction. Furthermore,
The gear 56 is arranged coaxially with the worm wheel 57, meshes with the idler gear 55, and the idler gear 55 meshes with the gear 54, whereby third deceleration is performed.

As shown in detail in FIG. 2, the worm wheel 57 is movable in the axial direction, and the compression spring 63 always keeps the worm wheel 57 in the gear 56.
By pressing in the direction of, the worm gear 58 and the worm wheel 57 are urged to mesh with each other. In addition, the state where the worm gear 58 and the worm wheel 57 are separated is configured to be detected by the sensor S5 and the filler 64 attached to the sensor S5. The filler 64 is rotatable about the axis e, and the sensor S5 is composed of a photo interrupter. Therefore, when the worm wheel 57 moves in the axial direction and comes into contact with the filler 64, the filler 64 rotates to block between the light emitting element and the light receiving element of the photo interrupter S5.

The worm wheel 57 and the gear 56, which can be meshed with each other, are provided with a recess 57a and a protrusion 56a which can be fitted as shown in FIGS. 3, 4 and 5, respectively. The concave portion 57a and the convex portion 56a are formed so that they can be fitted in the rotational direction of the worm wheel 57 and the gear 56 and can be separated from each other in the axial direction.
As shown in detail in FIG. 5, the tip has a thin end.

The operation of this drive mechanism will be described. First, when the DC motor 62 shown in FIG. 9 rotates, the timing pulley 61, the timing belt 60 and the timing pulley 5 are rotated.
9, the primary deceleration is performed, the worm gear 58 and the worm wheel 57 perform secondary deceleration, and the rotation shaft is converted from the vertical direction by 90 ° in the horizontal direction. The worm wheel 57, the gear 56, the idler gear 55 and the gear Third deceleration is performed by 54. Therefore, the rotation of the DC motor 62 is transmitted to the timing pulley 5 via the gear 54.
0, 51, the timing belt 52 and the discharge tray 3 move in the vertical direction.

If the discharge tray 3 is obstructed by an obstacle or the like when it descends, or if the stacking capacity of the sheet bundle on the discharge tray 3 is limited, the shaft between the worm wheel 57 and the gear 56 is set. Since the load in the direction increases, the worm wheel 5
7 separates from the gear 56 against the biasing force of the compression spring 63. Then, this state is detected by the sensor S5, and the DC motor 62 is controlled so as to stop.

Therefore, according to this embodiment, when the discharge tray 3 is obstructed by an obstacle or the like when descending, or when the stacking amount of the sheet bundle on the discharge tray 3 is limited, the worm wheel 57 and Since the gear 56 is disengaged, by considering the biasing force of the compression spring 63 and the angle of the convex portion 56a of the gear 56, the maximum load capacity of the tray can be improved with a simple configuration, and the tray can be lowered when the tray is lowered. It is possible to prevent damage due to an abnormality.

Further, a sensor S5 for detecting a state in which the discharge tray 3 is obstructed by an obstacle or the like when descending, or a state in which the stacking amount of the sheet bundle on the discharge tray 3 is limited is located at the position of the discharge tray 3. This abnormal state can be detected regardless of the position of the paper discharge tray 3 because it is provided at an irrelevant position.

Next, an application example of the above embodiment will be described with reference to FIGS. FIG. 6 shows an image forming apparatus 1 such as a copying machine.
6 is a side view showing a staple unit III provided with a sheet discharge port, FIG. 7 is an explanatory view showing a stapler of the staple unit III of FIG. 6, and FIG. 8 is a staple unit III of FIG.
FIG. 3 is a side view showing in detail the vicinity of the paper discharge port, and this staple unit III binds a bundle of copy paper with staples (needle) and discharges it to the paper discharge tray 3.

In FIG. 6, the leading edge and the trailing edge of the copy sheet discharged from the image forming apparatus 1 are the entrance sensor S1.
After being detected by the
The sheet is selectively conveyed by the deflecting claw 2 to the conveying path I directly guided to the discharge tray 3 or the conveying path II in the direction of the staple unit III. It should be noted that copy sheets that are not stapled and stapled copy sheet bundles are stacked on the discharge tray 3. Further, the deflecting claw 2 is controlled by a solenoid (not shown) and a spring so as to switch the conveyance path of the copy sheet.

In the conveying path I directly leading to the paper discharge tray 3, conveying rollers 5 and 6 and driven rollers 7 and 8 which are driven by the conveying rollers 5 and 6 are arranged, and a staple unit III is also provided.
Conveyance rollers 9 and 10 and driven rollers 11 and 12 that are driven by the conveyance rollers 9 and 10 are disposed on the conveyance path II in the direction of.

The staple unit III is shown in FIGS.
As shown in FIG. 3, a stapler 13 that is movable in the width direction of the paper according to the size of the paper, and a brush roller 15a for aligning the paper conveyance direction by abutting the rear end of the paper with the guide plate 14 are provided.
And a tapping roller 16, a jogger fence 15b for aligning the width direction of the paper, a discharge belt 17 and a discharge claw 18 for discharging the stapled bundle to the discharge tray 3.
And the like, and the paper ejection claw 18 is fixed to the paper ejection belt 17.

Next, the vicinity of the sheet discharge port of the staple unit III will be described in detail with reference to FIG. 8. For discharging the unstapled sheet and the stapled sheet bundle onto the sheet discharge tray 3 at this position. A paper discharge roller 19 is provided. Sensors S2 and S3 are provided at the respective exits of the conveyance path I directly leading to the paper discharge tray 3 and the conveyance path for the stapled sheet bundle (paper discharge belt 17 in the figure). Below the paper discharge roller 19, a sponge roller 20 is provided for pulling the paper.
Is placed, and the paper or stack of paper that has dropped onto the paper output tray 3
When the sponge roller 20 rotates, the sponge roller 20 is abutted against the guide plate 21 and the rear ends thereof are aligned.

As described above, the paper discharge tray 3 is movable in the vertical direction by the vertical guide rollers 22, and is moved by the drive mechanism shown in FIGS. 1 to 5 and 9. The paper discharge tray 3 is also movable in the width direction of the paper by the shift guide roller 23. This shift operation is performed by a drive mechanism (not shown). Here, above the sponge roller 20, there is provided a lever 26 and a sensor S4 for detecting the upper surface of the paper or the paper bundle ejected by the sponge roller 20, and the upper surface of the paper or the paper bundle is relative to the ejection roller 19. The height of the paper discharge tray 3 is adjusted so that it is always at a fixed position. Further, the driven roller 21 normally contacts the paper discharge roller 19 and can move to the position of the one-dot chain line together with the paper discharge guide plate 25 as the fulcrum a axis if necessary. This movement is performed by a drive mechanism (not shown). Be seen.

The staple unit III having such a configuration
Has a sort / stack mode in which sheets are discharged one by one to the discharge tray 3, and a staple mode in which a stapler 13 binds a bundle of sheets and discharges them to the discharge tray 3. In the sorting / stacking mode, the deflecting claw 2 shown in FIG. 6 is switched to the position indicated by the broken line, so that the copy sheet discharged from the image forming apparatus 1 is sent to the side of the conveying path I and is discharged by the conveying rollers 5, 6 and the like. It is discharged to the tray 3. in this case,
The driven roller 21 and the guide plate 25 are in contact with the paper discharge roller 19 under its own weight or under pressure by a spring, and thereby discharge the copy paper to the paper discharge tray 3.

On the other hand, in the staple mode, the deflecting claw 2 shown in FIG. 6 is switched to the position indicated by the solid line, so that the copy sheet discharged from the image forming apparatus 1 is sent to the side of the conveying path II, and the direction of the staple unit III is changed. Be transported to. In the stapling unit III, the set number of copy bundles are bound by the stapler 13 and conveyed toward the sheet discharge roller 19 by the sheet discharge belt 17 and the sheet discharge claw 18. In this case, the driven roller 21 and the guide plate 25 are not
The movement is controlled to the position indicated by the alternate long and short dash line so that the sheet bundle is separated from, and therefore the sheet bundle passes between the driven roller 21 and the sheet discharge roller 19. The trailing end of the sheet bundle is the driven roller 21.
Before passing between the discharge roller 19 and the discharge roller 19, the driven roller 21
And the guide plate 25 are controlled so as to press the sheet bundle,
Therefore, the sheet bundle is discharged onto the sheet discharge tray 3. Note that this control is performed by the detection signal of the sensor S3.

[0029]

As described above, according to the first aspect of the invention, the vertical drive means for moving the paper tray in the vertical direction, the motor for driving the paper tray in the vertical direction, and the motor. In a paper tray drive device including a transmission mechanism that transmits the rotation of the worm in the vertical direction, the transmission mechanism includes a worm gear that is rotated by the motor, and a worm wheel that is meshable with the worm gear and is movable in the axial direction. A recess which is provided with a gear coaxial with the worm wheel and an urging means for urging the worm gear and the worm wheel so that the worm gear and the worm wheel can mesh with each other, the recess being engageable in the rotational direction and detachable in the axial direction. Since the worm wheel and the gear are provided with the convex portion and the worm wheel, when the paper tray is not lowered or the paper tray is overloaded, the worm wheel Since load in the axial direction between the Eel and the gear is increased, the worm wheel and gear apart against the biasing force of the biasing means, disengages the engagement between the worm gear and the worm wheel. Therefore, it is possible to improve the maximum load capacity of the tray with a simple structure and prevent damage due to an abnormality when the tray is lowered.

According to a second aspect of the present invention, there is provided detection means for detecting that the worm wheel and the gear are disengaged in the first aspect of the invention, and the detection means causes the paper tray to be lowered abnormally and the paper tray to be loaded. Since the excess is detected, it is possible to detect an abnormal lowering of the paper tray and excess loading on the paper tray by one detecting means, and since this detecting means is provided at a position irrelevant to the position of the paper tray. This abnormal state can be detected regardless of the position of the paper tray.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a main part of an embodiment of a paper tray drive device according to the present invention.

FIG. 2 is a plan view showing a state where the worm gear and the worm wheel of FIG. 1 are disengaged from each other.

FIG. 3 is an explanatory view showing the worm wheel of FIGS. 1 and 2.

FIG. 4 is an explanatory view showing a gear mounted coaxially with a worm wheel.

5 is a perspective view showing in detail a fitting protrusion of the gear shown in FIG.

FIG. 6 is a side view showing a staple unit to which the paper tray driving device of FIGS. 1 to 5 is applied.

FIG. 7 is an explanatory diagram showing a stapler of the staple unit of FIG.

FIG. 8 is a side view showing in detail the vicinity of a paper exit of the staple unit of FIG.

FIG. 9 is a side view showing a general tray drive device.

[Explanation of symbols]

 3 Paper ejection trays 50 and 51 Timing pulley 52 Timing belt 56 Gear 56a Convex portion 57 Worm wheel 57a Recessed portion 58 Worm gear 62 DC motor 63 Compression spring S5 sensor

Claims (2)

[Claims] 1. A vertical drive means for vertically moving the paper tray, a motor for vertically driving the paper tray, and a transmission mechanism for transmitting the rotation of the motor in the vertical direction. In the paper tray drive,
The transmission mechanism includes a worm gear rotated by the motor, a worm wheel that is meshable with the worm gear and movable in the axial direction, a gear coaxial with the worm wheel, and the worm gear and the worm wheel mesh with each other. A paper tray comprising a urging means for urging the worm wheel and the gear, wherein the worm wheel and the gear are provided with a concave portion and a convex portion that can be fitted in the rotational direction and can be separated in the axial direction. Drive. 2. A detection means for detecting the disengagement of the worm wheel and the gear is further provided, and the detection means detects an abnormal lowering of the paper tray and an excessive stacking on the paper tray. 1. The paper tray drive device according to 1.