JPH1144329A - Rotation transmitting/cutting-off/stopping mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably synchronize transfer paper and a latent image formed on a photoreceptor with each other by reliably and temporarily stopping a moving body such as a document stand in a prescribed position without using an electric part. SOLUTION: In a rotation transmitting/cutting-off/stopping mechanism composed of a rectilinearly moving document stand (a moving body) 1, a rotation transmitting means (such as a driving motor 8) to drive the document stand 1 and a cutting-off means to temporarily cut off the rotation transmission of the rotation transmitting means, the cutting-off means is composed of a platen lever (a cutoff control lever) 6 rotatably provided with a spring clutch 5, tension springs (energizing means) 13a and 13b to energize the platen lever 6 and a fixing holding means to fix the load side of the spring clutch 5. When a part (a cam 7) of the document stand 1 engages with the platen lever 6, the platen lever 6 operates to the spring clutch 5, and the rotation transmission is cut off, and after this operation finishes, a load side part of the spring clutch 5 is fixed by the fixing holding means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation transmission cutoff stop mechanism provided in an image forming apparatus for reading image information, forming the information on a recording medium, and transferring the information to a transfer sheet.

[0002]

2. Description of the Related Art An image forming apparatus, particularly a movable platen copy machine, has an optical system for synchronizing an image on a photosensitive drum formed by scanning a document with a transfer sheet to which the image is to be transferred. Is temporarily stopped, and then the optical system is restarted.

The copying operation of such an original platen type copying machine will be described with reference to FIGS. 8 to 11
FIG. 1 is a cross-sectional view of a conventional original platen movable copying machine.

When a copy start signal is input by pressing a copy button (not shown), a main motor (not shown) starts driving. As a result, the document table 1 including the platen glass starts moving in the direction of the arrow (left direction) in FIG. 8 and enters a preparatory operation for scanning. At this time, only the middle plate 2 starts rotating in the paper feeding section on which the transfer paper is placed, and operates so as to press the loaded transfer paper against the paper feed roller 3.

FIG. 9 shows a state in which the movement of the document table 1 to the home position has been completed and the rotation of the intermediate plate 2 has been completed. When the platen 1 arrives at the home position, the detecting means detects this and gives a signal to the drive system, and the platen 1 is driven to operate in the scanning direction (the direction of the arrow in FIG. 10). At the same time, the drive transmission to the paper feed roller 3 is started, and the transfer paper stacked on the paper feed unit is fed. The document table 1 driven in the scanning direction moves from the home position to the position shown in FIG. 10, temporarily stops, and enters a standby state. During this time, the transfer paper continues to be transported, and its leading end reaches a position where the registration sensor lever 4 is rotated. When the registration sensor lever 4 rotates, it recognizes that the transfer paper and the document are synchronized, and the scanning operation of the document table 1 is started again as shown in FIG.

[0006] Through the above operations, the latent image on the photosensitive drum 30 and the transfer paper are synchronized.

Next, the driving of the document table 1 will be described with reference to FIG.

FIG. 12 shows a state where the document table 1 is moving from the home position in the scanning direction and immediately before the document table 1 is temporarily stopped. In FIG. 12, reference numeral 7 denotes a cam fixed to the document table 1. The cam 7 moves with the scanning operation of the document table 1.

The cam 7 is arranged at a position where it engages with a lever 6 rotatably provided at a predetermined position.
When the lever 6 is rotated by engagement with the cam 7, its tip engages with the control ring of the spring clutch 5 provided in the drive system. By this operation, the drive transmission to the document table 1 is interrupted, and the scanning operation is temporarily stopped.

[0010]

However, in the above-mentioned conventional example, the movement of the document table 1 is temporarily stopped only by interrupting the rotation transmission by the spring clutch 5, and thus has the following disadvantages.

That is, when some external force is applied to the document table 1 in the pause state, the position of the document table 1 easily shifts.

When the original placed on the original table 1 is a heavy book such as an encyclopedia, if the movement of the original table 1 is temporarily stopped only by interrupting the rotation transmission, the original table 1 Does not stop momentarily due to its own inertial force.

For the above reasons, there has been a problem that stable synchronization cannot be obtained between the transfer paper and the latent image formed on the photosensitive member.

[0014] The present invention has been made in view of the above problems, and the object thereof is to use an electric component without using an electric part.
To provide a rotation transmission cut-off stop mechanism that enables a moving body such as a platen to be temporarily stopped at a predetermined position to enable stable synchronization between a transfer sheet and a latent image formed on a photoconductor. is there.

[0015]

In order to achieve the above-mentioned object, according to the present invention, there is provided a moving body which moves linearly, rotation transmitting means for driving the moving body, and rotation of the rotation transmitting means. In a rotation transmission interruption stop mechanism configured to include an interruption means for temporarily interrupting transmission, the interruption means biases the interruption control lever rotatably provided with a clutch and the interruption control lever. And a fixed holding means for fixing the load side of the clutch, and a part of the moving body is engaged with the cutoff control lever so that the cutoff control lever operates with respect to the clutch to transmit the rotation. Is cut off, and after the operation is completed, the load-side portion of the clutch is fixed by the fixing and holding means.

According to a second aspect of the present invention, in the first aspect of the present invention, the clutch comprises a rotating shaft, an input portion and an output portion rotatably attached to the shaft, and the input portion and the output portion. A spring portion wound around a clutch body integrally formed with the portion, and a control ring fitted on the outer periphery of the spring portion and rotatable with respect to the shaft. A locking portion is formed over the entire circumference of the portion, a gear integrated with the locking portion is provided on the clutch output side of the shaft, and the outer diameter of the locking portion of the control ring is set to The stop is set to be larger than that of the stop.

According to a third aspect of the present invention, in the first aspect of the present invention, the clutch has an input gear and an output gear rotatably mounted on a shaft, and the output gear is connected in the axial direction. When the clutch is released, the clutch operates as a clutch. The output gear also has a protrusion on the opposite side of the face facing the input gear, and the cutoff control lever is engaged with a part of the output gear and the moving body. The output gear is separated from the input gear in the axial direction by the combination, and the fixed holding means is configured to lock the convex portion of the output gear.

According to a fourth aspect of the present invention, in the first, second or third aspect of the present invention, the shutoff control lever is provided with an urging force by an elastic member or a member to which an urging force is applied from the elastic member, thereby shutting off. Before the operation, the clutch is separated from the clutch by an urging force, but after the disconnection operation, the clutch is urged in a direction opposite to the direction.

Therefore, according to the present invention, when a part of the moving body is engaged with the cutoff control lever, the cutoff control lever operates with respect to the clutch to cut off the rotation transmission, and after this operation is completed, the fixed holding is performed. The load-side part of the clutch is fixed by means, and the rotation transmission is shut off and the moving body is locked in a timely and reliable manner. The moving body such as the platen is reliably temporarily stopped at a predetermined position without being affected by the above, and without using electric parts, so that a stable image is formed between the transfer paper and the latent image formed on the photosensitive body. Synchronization can be enabled.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIGS. 1 to 3 are front views showing the configuration of a drive system of a copying machine having a rotation transmission cutoff / stopping mechanism according to a first embodiment of the present invention.

When the drive system is driven by the drive motor 8 shown in FIG.
Rotates, and the platen drive gear 9 drives the rack gear 12 integrated with the platen 1. The platen lever 6
When it engages with the cam 7 provided on the moving document table 1, it rotates counterclockwise around the support shaft. The tension spring 13a urges the platen lever 6 clockwise in the drawing.

FIG. 2 shows the state at the moment when the document table 1 reaches a predetermined point and the drive blocking means operates. When the platen lever 6 is rotated counterclockwise about the support shaft by the cam 7, the engagement between the platen lever 6 and the solenoid lever 10 is released.

The solenoid lever 10 is urged clockwise about a rotation axis by a tension spring 13b.
The spring constants of the tension springs 13a and 13b are set so that the clockwise moment of 0 is greater than the clockwise moment of the platen lever 6 by the tension spring 13a.

Since the spring constants of the tension springs 13a and 13b are set as described above, the two levers 6 and 10 after the disengagement of the platen lever 6 and the solenoid lever 10 are as follows. Works like that.

That is, the platen lever 6 rotates clockwise. Then, the movement of the tip of the platen lever 6 causes the solenoid lever 10 to rotate counterclockwise, and moves to the state shown in FIG. The platen lever 6 receives a biasing force from the hatched portion 10-a by the solenoid lever 10, and the force acting from the hatched portion 10-a is a vector directed in substantially the same direction as the rotation center of the platen lever 6. The solenoid lever 6 and the platen lever 10 are configured so that
0 stands still while maintaining the state shown in FIG.

When the above operation is completed, the tip of the platen lever 6 is engaged with the spring clutch 5. Here, the details of the platen lever 6 and the spring clutch 5 will be described with reference to FIGS.

FIG. 4 is a perspective view from the spring clutch 5 to the rack gear 12 provided on the document table 1. As shown in FIG. 4, the drive from the drive motor 8 (see FIG. The rotation is input to the input gear 5 b and transmitted to the shaft 15. The control ring 5e of the spring clutch 5 has a locking portion 5a having a tooth shape.

A transmission gear 14 is fixed on the shaft 15 with a parallel pin in a rotational direction with respect to the shaft 15. The transmission gear 14 controls the rotation of the shaft 15 by a document table driving gear. 9 The transmission gear 14 is a gear portion 14
b and a locking portion 14a, and the locking portion 14a has a shape similar to the locking portion 5a of the spring clutch 5.

As the document table 1 moves, the cam 7 (FIG. 1)
3 to FIG. 3), the distal end of the platen lever 6 which starts the operation is constituted by forked claws 6a and 6b.
The pawls 6a and 6b are configured to engage with the locking portion 5a of the control ring 5e of the spring clutch 5 and the locking portion 14a of the transmission gear 14, respectively.

Next, the drive transmission operation of the spring clutch 5 will be described with reference to FIGS.

FIG. 5A shows a state where the drive is transmitted to each section and the document table 1 is moving in the scanning direction. The spring clutch 5 includes a gear unit 5b and an output unit 5d,
A winding spring 5c wound around a clutch body integrally formed with the gear portion 5b and the output portion 5d;
The control ring 5e has a control ring 5e which is fitted around the outer periphery of the coil spring 5c and is rotatable.
The other end is locked to the output section 5d. still,
The output part 5d is fixed in the rotation direction with respect to the shaft 15 by a parallel pin.

When rotation is transmitted from the gear portion 5b of the spring clutch 5, the winding spring 5c
Is urged in the tightening direction and rotates in the same direction as the gear portion 5b. At this time, since the winding spring 5c is simultaneously tightening the output portion 5d, the output portion 5d is rotated by the tightening force, and the shaft 5 is rotationally driven via the parallel pin.

When the platen 1 has moved to a predetermined position, the platen lever 6 is rotated by engagement with the cam 7 as described above. Lock.

As shown in FIG. 5B, the spring clutch 5
The control ring 5e of the spring clutch 5 is locked by the platen lever 6 because the outer diameter of the locking portion 5a of the control ring 5e is larger than that of the locking portion 14a of the transmission gear 14. The state in which the locking portion 14a is not locked is reliably realized. At this time, since the control ring 5e is locked, the winding spring 5c fixed to its end is released from the tightened state, and the rotation transmission to the output section 5d is cut off.

After the above operation is reliably performed, a state shown in FIG. 5C is reached, that is, a state in which the pawl 6b of the platen lever 6 is engaged with the locking portion 14a of the transmission gear 14. When this state is achieved, the rotation of the transmission gear 14 is completely locked, and the movement of the document table 1 is completely stopped.

Referring again to FIG. 2, the document table 1 is moved to a predetermined position, and the cam 7 rotates the platen lever 6 to thereby move the platen lever 6 to the position shown in FIG.
(B) (that is, the control ring 5 of the spring clutch 5)
e is locked).

Thereafter, the state shown in FIG.
The operation up to the state shown in (c) is performed by the tension spring 1 provided on the platen lever 6 and the solenoid lever 10.
This is performed by the action of the restoring force of 3a and 13b.

Therefore, even if, for example, the sliding resistance of the movement of the document table 1 is abnormally high and the movement is completely stopped at the moment when the rotation transmission is interrupted, the subsequent operation of the platen lever 6 and the solenoid lever 10 will not occur. It is configured to be surely terminated.

Thus, the original table 1 waits until the transfer sheet conveyed in the main body operates the registration sensor lever 4 shown in FIG. When the registration sensor lever 4 operates, a signal is sent via a main body control unit (not shown),
The solenoid 11 shown in FIGS. 1 to 3 is operated, but when the solenoid 11 is operated, the solenoid lever 10 is operated.
Rotates counterclockwise to disengage it from the platen lever 6. For this reason, the platen lever 6 is connected to the tension spring 13a.
Due to the restoring force of (1), the tip rotates away from the engaging portion 5a of the spring clutch 5 or the engaging portion 14a of the transmission gear 14. Then, the rotation interrupted by the spring clutch 5 is transmitted to the platen drive gear 9, and the platen 1 restarts.

As described above, according to the present embodiment, the control ring 5e of the spring clutch 5 and the transmission gear 14 disposed coaxially with the control ring 5e are provided with the engaging portions 5a, 14a having tooth shapes. Further, the outer diameter of the locking portion 5a of the spring clutch 5 is set to be larger than that of the locking portion 14a of the transmission gear 14, and a platen lever 6 that rotates in conjunction with the movement of the document table 1 is provided. , Each pawl 6 with this platen lever 6
a and 6b are engaged in the order of first the locking portion 5a of the spring clutch 5 and secondly the locking portion 14a of the transmission gear 14, so that the document table 1 can be used only with mechanical components without using electric elements. Can be stopped at a stable position.

By devising the shape of the engaging portion between the platen lever 6 and the solenoid lever 10 and the tension spring 13b of the solenoid lever 10, the transmission gear 14 is locked from the locked state of the spring clutch 5. Up to the tension spring 13 regardless of the movement of the platen 1.
a, 13b, the restoring force is applied, regardless of the weight of the original placed on the original platen 1 and the slidability of the sliding portion.
After the operation of interrupting the drive transmission, the operation of locking the original platen 1 that has definitely become free can be performed.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a perspective view of a rotation transmission cutoff / stopping mechanism according to Embodiment 2 of the present invention, and FIG. 7 is an operation explanatory view of the rotation transmission cutoff / stopping mechanism.

Drive is transmitted from the motor to the coupling input gear 21 shown in FIG.
A convex portion 21a and a concave portion 22a (see FIG. 7) are formed on opposite side surfaces of the coupling gear 1 and the coupling output gear 22, respectively.
The two gears 21 and 22 are configured to engage with each other by a convex portion 21a and a concave portion 22a, and transmit rotation on the same axis.

The coupling output gear 22 meshes with a platen drive gear 27, and the platen drive gear 27 meshes with a rack integrated with the platen 1 to drive the platen 1. The platen lever 25 is a rotatable lever urged clockwise by a coil spring 26, and rotates in conjunction with the movement of the document table 1 to operate the drive cutoff lever 23. . The drive cut-off lever 23 engages with the coupling output gear 22 by its rotating operation to slide it in the axial direction.

The tension spring 24 is mounted on the drive cut-off lever 23, and applies a counterclockwise or clockwise moment to the drive cut-off lever 23 depending on the posture of the drive cut-off lever 23. Also, the solenoid 11
As described later, after the drive cut-off lever 23 is operated by the movement of the document table 1, the drive cut-off lever 2 is operated by receiving a detection of the position of the transfer sheet in the main body and operated by a signal transmitted from the control unit.
3 is returned to the driving connection state.

Next, the operation of the rotation transmission cutoff / stopping mechanism according to this embodiment will be described with reference to FIG.

FIG. 7A shows an initial state. In this state, the rotation is transmitted from the coupling input gear 21 to the coupling output gear 22, and the document table 1 is driven.
As shown in FIG. 6, when the document table 1 moves to a predetermined position, the document table 1 engages with the platen lever 25 and
The drive cut-off lever 23 is rotated as shown in FIG. As a result, the coupling between the coupling input gear 21 and the coupling output gear 22 is released, and the rotation transmission is interrupted. At this time, at the same time, the tension spring 24 is in a positional relationship such that the restoring force acts on the drive cut-off lever 23 from a counterclockwise to clockwise moment. Thereafter, the drive cut-off lever 23 changes from the state shown in FIG. 7B to the state shown in FIG. 7C only by the restoring force of the tension spring 24, and the coupling output gear 22 is urged by the side plate 27. At the same time, the projection 22b of the coupling output gear 22 is engaged with the hole 27a formed in the side plate 27, and the state is locked.

According to the operation described above, the first embodiment
In the same manner as described above, the cutoff of the driving of the original table 1 is completed, and thereafter, the original table 1 side can be securely locked.

[0050]

As is apparent from the above description, according to the present invention, when a part of the moving body is engaged with the cutoff control lever, the cutoff control lever operates with respect to the clutch to cut off the rotation transmission. After this operation is completed, the load side portion of the clutch is fixed by the fixing holding means,
The transmission of rotation and the locking of the moving body are performed in a timely and reliable manner, so that they are not affected by the slidability of the moving body and the inertial force associated with the mass, and electric components must be used. In addition, a moving body such as a document table can be reliably temporarily stopped at a predetermined position, and an effect of enabling stable synchronization between a transfer sheet and a latent image formed on a photosensitive body can be obtained. .

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a drive system of a copying machine including a rotation transmission cutoff / stopping mechanism according to Embodiment 1 of the present invention.

FIG. 2 is a front view showing a configuration of a drive system of a copying machine including a rotation transmission cutoff / stopping mechanism according to Embodiment 1 of the present invention.

FIG. 3 is a front view showing a configuration of a drive system of a copying machine including the rotation transmission cutoff / stopping mechanism according to Embodiment 1 of the present invention.

FIG. 4 is a perspective view of a rotation transmission cutoff / stopping mechanism according to Embodiment 1 of the present invention.

FIG. 5 is an operation explanatory view of a spring clutch of the rotation transmission cutoff / stopping mechanism according to the first embodiment of the present invention.

FIG. 6 is a perspective view of a rotation transmission cutoff / stopping mechanism according to Embodiment 2 of the present invention.

FIG. 7 is an operation explanatory view of a rotation transmission cutoff / stopping mechanism according to Embodiment 2 of the present invention.

FIG. 8 is a cross-sectional view of a conventional platen movable copying machine.

FIG. 9 is a cross-sectional view of a conventional original platen movable copier.

FIG. 10 is a cross-sectional view of a conventional original platen movable copier.

FIG. 11 is a cross-sectional view of a conventional original platen movable copier.

FIG. 12 is a cross-sectional view for explaining driving of a document table of a conventional document table movable type copier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original table (moving body) 5 Spring clutch (clutch) 5a Locking part 5b Gear part (input part) 5c Winding spring (spring part) 5d Output part 5e Control ring 6 Platen lever (interruption control lever) 7 Cam 8 Drive motor Reference Signs List 9 platen drive gear 10 solenoid lever (cutoff control lever) 13a, 13b tension spring (elastic body) 14 transmission gear 14a locking part 15 shaft 21 coupling input gear (input gear) 22 coupling output gear (output gear) 23 Drive cut-off lever (cut-off control lever) 24 Tension spring (elastic body) 25 Platen lever (cut-off control lever) 26 Coil spring (elastic body) 27 Platen drive gear

Claims (4)

[Claims] 1. A rotation transmission block comprising a moving body that moves linearly, a rotation transmitting unit for driving the moving body, and a blocking unit that temporarily blocks the rotation transmission of the rotation transmission unit. In the stop mechanism, the disconnecting means includes a disconnecting control lever rotatably provided with the clutch, a biasing means for biasing the disconnecting control lever, and a fixed holding means for fixing the load side of the clutch. When a part of the moving body is engaged with the cutoff control lever, the cutoff control lever operates on the clutch to cut off the rotation transmission, and after this operation is completed, the fixed holding means closes the load side of the clutch. A rotation transmission cutoff / stopping mechanism characterized in that the portion is fixed. 2. The clutch is wound around a rotating shaft, an input portion and an output portion rotatably mounted on the shaft, and a clutch body integrally formed with the input portion and the output portion. And a control ring fitted on the outer periphery of the spring portion and rotatable with respect to the shaft, and a locking portion is formed over the entire outer periphery of the control ring. ,
A gear integrated with a locking portion is provided on the clutch output side of the shaft, and an outer diameter of the locking portion of the control ring is set to be larger than that of the locking portion of the gear. Item 4. The rotation transmission cutoff stop mechanism according to Item 1. 3. The clutch has an input gear and an output gear rotatably mounted on a shaft, and the output gear is engaged and disengaged in the axial direction to perform a clutch action. The reverse surface of the surface opposite to the input gear also has a convex portion, and the cutoff control lever axially moves the output gear from the input gear by engaging with a part of the output gear and the moving body. 2. The rotation transmission cut-off stop mechanism according to claim 1, wherein the fixed holding means is configured to lock the projection of the output gear. 4. The disconnection control lever is provided with an urging force by an elastic member or a member to which an urging force is applied from the elastic member, and is separated from the clutch by the urging force before the disconnection operation. The rotation transmission interruption stop mechanism according to claim 1, 2, or 3, wherein the clutch is urged in a direction opposite to the direction after the clutch.