JPH0160690B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a clutch device, and more particularly to a clutch device used in a drive device for an optical device that optically scans a document, such as a copying machine, a facsimile machine, an electrostatic recording device, or the like.

Prior Art In copying machines, facsimile machines, electrostatic recording devices, and especially color electrophotographic copying machines, it is necessary to accurately synchronize the scanning movement of a scanning optical device with the movement of a photoreceptor, for example, the rotation of a photoreceptor drum. This was required to prevent color shifts in images.

For example, in a color electrophotographic copying machine using a visible image transfer method, a color original image is color-separated into blue, green, and red light images through a color separation filter, and a photoreceptor is exposed to each color using the color-separated light. The resulting electrostatic latent image is developed individually with a developer of a color complementary to each color to make it visible, and the visible images of each separated color are sequentially transferred onto a copy sheet in an overlapping manner. .
In such a color electrophotographic copying machine, the original is scanned by reciprocating the original or the optical device a number of times according to the number of separated colors, and an electrostatic latent image is repeatedly formed for each separated color at the same position on the photoreceptor. be done. In this case, if the position of the electrostatic latent image on the photoreceptor is shifted due to color separation, color shift occurs in the image on the copy paper, resulting in a decrease in image quality. To prevent this, the movement of the document table or optical device that moves during document scanning and the movement of the photoreceptor must be accurately synchronized with each other.
In order to obtain this movement, it is necessary to accurately synchronize at the start of operation and during operation.

The scanning system drive device that moves the document table or the optical device is formed as a transmission device in which the rotational force of the rotary drive device is transmitted through a clutch mechanism such as an electromagnetic clutch or a spring clutch, and scanning is performed by turning on and off the clutch mechanism. The start of movement of the system is controlled.
However, the use of a clutch mechanism has the disadvantage of causing variations in the rise time until the driving force is completely transmitted, making it unsuitable for applications such as color electrophotographic copying machines that require precise synchronization.

In order to eliminate this drawback, a clutch having a clutch ring having a locked portion, a locking portion that engages and disengages the locked portion of the clutch wheel, and means for controlling the operation of the locking portion are provided. A device has been proposed to eliminate variations in rise time, but if the mechanism stops due to a power outage, accidental power off, or other trouble during scanning, the locking part remains engaged with the clutch wheel. There was a problem in that the method of resetting the locking part was complicated.

Purpose The present invention relates to an optical device such as a copying machine (including a manuscript table).
It is possible to solve the problems of the above-mentioned conventional drive device, for example, to achieve precisely synchronized drive of the photoreceptor and optical device, and to easily and reliably restore normal operation even in the event of trouble during scanning movement. It is an object of the present invention to provide a clutch device for a drive device that is compact and can be used even in an optical device having a variable magnification function.

Configuration A configuration for achieving the above object according to the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows an example of a color electrophotographic copying machine embodying the present invention. Naturally, the present invention is not limited to this copying machine, but can be applied to facsimile machines, electrostatic recording devices, etc., but only the case of a copying machine will be described below.

In FIG. 1, an illumination device 3 having a lamp 2 and a first mirror 4 scan and move at the same speed with respect to an original table 1 whose position is fixed, while a second mirror 5 and a third mirror move at the same speed.
Mirror 6 moves back and forth synchronously at 1/2 speed.
Conversely, it is also possible to reciprocate the document table 1 and fix the above-mentioned optical members in position.

The illumination light for the document on the document table 1 passes through the first mirror 4, the second mirror 5, and the third mirror 6 and enters the lens 7, and the projected light from the lens 7 passes through the fourth mirror 8 and the color separation filter 9. Then photosensitive drum 10
The image is exposed and projected. Around the photosensitive drum 10, a charger 11, a developing device 12, a transfer drum 13, a separation charger 14, a cleaning device 15, and a charger 16 for neutralizing electricity are arranged in this order.

The photosensitive drum 10 is driven in synchronization with the illumination device 3, and when the illumination device 3 scans and illuminates the original once by forward movement, the photosensitive drum 10 rotates once and the light image of the original is exposed on the photosensitive drum, using a well-known method. to form an electrostatic latent image. The color separation filter 9 is the lighting device 3
It is switched every reciprocating movement of the photosensitive drum 10, that is, every rotation of the photosensitive drum 10, and a latent image of a different separated color is formed on the photosensitive drum 10 every rotation.

The latent image on the photosensitive drum 10 is developed with a developer of a color determined by the color separation of the filter during exposure. The figure shows an example in which the image is separated into three colors, and the developing device 12 includes three types of developing units corresponding to each developing color.

Copy paper is fed from the paper feeder 17 to the transfer drum 13 at a certain timing with the scanning exposure of the original, and under the action of the transfer charger 18, the copy paper is transferred to the photosensitive drum 1.
An image is transferred from 0 to copy paper. The above process is repeated as many times as the number of separated colors, and the transfer drum 1
The copy paper affixed to 3 is transferred from the photosensitive drum as many times as the number of separated colors.

When the image transfer of all separated colors is completed, the copy paper is separated from the transfer drum 13 under the action of the separation charger 19 and the separation claw 20, fixed by the fixing device 21, and discharged.

A driving device for a scanning optical device according to the present invention used in a copying machine as described above will be described.

In FIG. 2, the lighting device 3 and the first mirror 4
A bracket 22 carrying a mirror 5 and a mirror bracket 23 carrying a second mirror 5 and a third mirror 6 are each slidably guided by a guide rod 24.

The mirror drive device 25 includes a scan return servo motor 26 and a drive wire 28 wound around a pulley 27 attached to the output shaft of the motor.
is provided. As shown in FIG. 2, the drive wire 28 is connected from the pulley 27 to a fixed pulley 29, a fixed pulley 30, a movable pulley 31, a fixed pulley 32, a tension adjustment pulley 33, a movable pulley 31, a fixed pulley 34, and a fixed pulley 2.
9. It is formed as a closed loop that sequentially passes through the transmission pulley 35 and returns to the pulley 27, and in the middle of the loop, for example, the movable pulley 31 and the fixed pulley 34
A bracket 22 is fixed to the drive wire 28 between the drive wire 28 and the drive wire 28. The movable pulley 31 is rotatably supported by the mirror bracket 23. With this structure, the bracket 22, ie, the illumination device 3, and the first mirror 4 are moved by the distance traveled by the drive wire 28, whereas the mirror bracket 23, ie, the second mirror 5, and the third mirror 6 are moved by 1 of the distance traveled by the drive wire 28. /2 in the same direction as bracket 22.
By tensioning the tension adjustment pulley 33 with a spring 36, loosening of the drive wire is prevented.

A transmission pulley 35 of the scanning optical device is fixed to a driven shaft 36 to which a driven gear 37 as a driven member is fixed, and is drivingly connected to the driven gear 37. The driven gear 37 is driven and connected by meshing with a drive gear 39 serving as a drive member rotatably supported by a drive shaft 38 .

The drive gear 39 is provided with a lug 40, and the lug 40
The substantially central portion of the claw arm 41 is pivotally supported by a pin 41' and is swingable. The claw arm 41 has a claw 42 at one end, and the other end is formed as a release operating portion 43. A ratchet wheel 44 that can be engaged with a pawl 42 of a pawl arm 41 is fixed to the drive shaft 38 . A drive gear 39 with a pawl arm 41 and a pawl wheel 44 form a pawl clutch.

Since the pawl arm 41 is given a force to be pressed against the outer periphery of the pawl wheel 44 by a spring or the like (not shown), the pawl wheel 44 rotates and engages the engagement recess 44 of the pawl wheel 44.
When a comes to a position facing the pawl 42 of the pawl arm 41, the pawl 42 automatically engages with the engagement recess 44a, the clutch is turned on, and the rotation of the pawl wheel 44 moves to a certain relative position to the drive gear 39. communicated in relationships. When the drive gear 39 rotates once and reaches a predetermined position, the release operating portion 43 of the pawl arm 41 comes into contact with the release pin 65 fixedly arranged on the frame, and the pawl arm 41 is rotated around the fulcrum to release the pawl. 42 is disengaged from the engagement recess 44a, the clutch is turned off, and transmission between the drive gear 39 and the ratchet wheel 44 is interrupted. The transmission pulley 3 is rotated by one rotation of the drive gear 39.
5, the scanning optical device, that is, the illumination device 3 and the mirrors 4, 5, and 6 are moved back and forth for scanning and then stopped.

A blade support plate 45 that is loosely fitted onto the drive shaft 38 and fixedly supported by the frame as shown in FIG. 4 as a clutch disengagement means;
As shown in FIG. 5, there are two sets of blades 46, each consisting of two blades 46 rotatably supported by pins 47 at substantially diametrically opposed positions. Two sets of blades 46 are attached to the front and back surfaces of the blade support plate 45, and the support positions of the blades 46 attached to the front surface and the blades attached to the back surface by the pins 47 are relatively shifted by about 90 degrees. Set. Incidentally, one or more blades can be arbitrarily selected. As shown in FIG. 7, the blade 46 rotatably supports a roller 49 at its free end, and has a support pin 47 of the blade on the opposite side, and a first hole 50 and a first hole through which the axis of the roller 49 passes through the middle portion. It has two holes 51, respectively. The first hole 50 and the second hole 51 are formed as elongated holes (linear or arcuate) so as not to prevent the blade 46 from swinging around the pin 47 within a predetermined angular range. The outer circumferential surface 46a of the blade 46 is formed in a substantially arc shape, and forms approximately a part of the circumference at the position where the blade 46 rotates to the outermost side around the pin 47. That is, when the outer peripheral surfaces of the two sets of four blades 46 are connected, they approximately form a circle. The circumference formed by the blade 46 turning outward (outer circumference in Fig. 5; virtual circle in Fig. 6) is the expanded circumference; the circumference formed by turning inward (outer circumference in Fig. 6) is the contracted circumference. It is called.

A blade control plate 52 is arranged concentrically with the blade support plate 45 and rotatable relative to the blade support plate 45.
(equivalent to the arc around the center of pin 47)
A groove 53 opening radially outwardly along the blade 46 is formed at a position such that the roller 49 at the free end of the blade 46 engages, as shown in FIG. are fixed or integrally formed. A plunger of a solenoid 55 is connected to the lever 54, and a spring 56 is locked to the lever 54 so as to apply a tensile force in the opposite direction to the suction force of the solenoid 55. Lever 54
When pulled by the suction force of the solenoid 55, the lever 54, that is, the blade control plate 52, is rotated clockwise in FIGS. The state shifts to the reduced state shown in FIG. When the solenoid 55 is deenergized, the lever 54 is moved counterclockwise by the force of the spring 56, and the blade 46 transitions to the expanded state shown in FIG.

As shown in FIG. 4, the blade 46 is disposed adjacent to the ratchet wheel 44, and the outer peripheral surface 46a of the blade 46 is connected to a pawl roller 57 rotatably supported by the pawl 42 of the pawl arm 41, as shown in FIG. Since the blade 46 is formed as a guide surface (in other words, a cam surface) in contact with the pawl arm 41 when the blade 46 is in the expanded state as shown in FIG. The claw 42 is pushed outward against the
is held in a state where it cannot engage with the engagement recess 44a of the ratchet wheel 44. That is, the pawl clutch is held in the OFF state. The rotation of the ratchet wheel 44 is not transmitted to the first gear 39. On the other hand, when the blade 46 is in the retracted state shown in FIG. 6 due to the movement of the lever 54, the claw arm 41 has a spring (not shown) tendency to rotate clockwise around the fulcrum in FIGS. 3 and 9. Since it is given by, we move to the state shown in Figure 9B,
The claw 42 can engage with the engagement recess 44a of the ratchet wheel 44. The clutch is ON in this engaged state.
In this state, the rotation of the ratchet wheel 44 is transmitted to the drive gear 39, that is, the transmission pulley 35. In that case, the clutch is turned on and off by the operation of solenoid 55.
controlled.

A driven gear 58 is fixed to the drive shaft 38 to which the ratchet 44 is fixed, and the driven gear 58 is driven to an idle gear by a drive gear 60 fixed to an input shaft driven by a main drive device (not shown) via a belt or the like. 61. On the other hand, the driving gear 60 meshes with a gear 62 fixed to the photosensitive drum 10,
The photosensitive drum 10 is driven. The photosensitive drum 10 and the transfer drum 13 are driven at a one-to-one speed by a pair of gears 63 and 64 that mesh with each other.

The operation of the present invention will be explained.

A drive device (not shown) drives the photosensitive drum 10 and the transfer drum 13 via gears 60 and 62, and in synchronization with the drive of the transfer drum 13, the ratchet wheel 44 is driven via the gears 61 and 58. Since one engagement recess 44a is formed in the ratchet wheel 44, the relative timing between the photosensitive drum 10 and the engagement recess 44a is always kept constant.

When the pawl wheel 44 rotates to a predetermined position, the pawl arm 41
The pawl clutch is turned on by the engagement of the pawl 42 with the engagement recess 44a, the drive gear 39 is driven, and the illumination device 3 and mirrors 4, 5, 6 are connected to the photosensitive drum 10.
When the pawl wheel 44, which exposes the optical image of the document onto the photosensitive drum 10, rotates once, the pawl clutch is turned off by the cooperation of the release pin 65 and the pawl arm 41, and the scanning drive of the optical device is turned off. will be stopped. On the other hand, the photosensitive drum 10 and the transfer drum 13 are stopped after completing a predetermined operation.

The optical device including the illumination device 3 is connected to the pawl clutch.
When the servo motor 26 for scan return is activated by scanning following OFF and stopped, the photosensitive drum 1 is
It is returned to the standby position regardless of the zero rotation. The gear 39 rotates in the opposite direction to the ratchet wheel 44, and the pawl 42 arrives and waits before the groove 44a of the ratchet wheel 44 reaches the regular engagement position.

Repeat the following operations.

If the device stops midway due to a power outage or the power is accidentally turned off, it will stop with the claw clutch engaged, but of course it will turn off if the power is cut off or the power is accidentally turned off. In addition, in the event of equipment trouble, the power to the solenoid is immediately turned off, so in any of the above cases, the solenoid is turned off, the clutch is released, and the scan return servo motor 26 is immediately turned off.
By the operation of , it becomes possible to return to the standby position, that is, the home position. Therefore, when the copying cycle is stopped in the middle, the illumination device etc. can be immediately returned to the home position.

Effects According to the present invention, when the scanning optical device stops at an arbitrary position, it can be reliably and quickly reset to the home position by providing a means with a simple structure of expandable and retractable means having four blades. became possible.

Furthermore, by selecting the operating conditions of the solenoid, the starting position of the optical device's return movement can be arbitrarily selected according to the size of the document, regardless of the rotation of the photosensitive drum, and the reciprocating stroke of the scanning optical device can be adjusted to the size of the document. It is now possible to change it arbitrarily.

By providing the clutch release means according to the present invention, it has become possible to obtain a reliable pawl clutch with no timing deviation in engagement and disengagement of the clutch with a simple structure in which one engagement recess is a pawl.

[Brief explanation of drawings]

FIG. 1 is a schematic illustration of a copying machine that utilizes the present invention;
2 is a perspective view of a part of the drive device of the scanning optical device, FIG. 3 is a perspective view of another part of the drive device of the scanning optical device, and FIG. 4 is a side cross-section of the clutch portion and clutch disengagement means. 5 is a front view of the clutch disengagement means in an expanded state, FIG. 6 is a front view of the clutch disengagement means in a contracted state, FIG. 7 is a perspective view of the blade, and FIG. 8 is a blade control plate. front view,
FIG. 9 is a view showing the relationship between the pawl arm of the pawl clutch, the ratchet wheel, and the outer surface of the blade of the clutch disengagement means, with A showing the outer surface of the blade when it is expanded, and B showing when the outer surface of the blade is contracting. 1... Original table, 3... Lighting device, 4, 5, 6...
... Mirror, 25 ... Drive device, 26 ... Reverse motor, 28 ... Wire, 35 ... Transmission pulley, 39 ... Drive gear, 41 ... Claw arm, 42
...claw, 44 ... ratchet wheel, 45 ... blade support plate, 46 ... blade, 47 ... pin (fulcrum),
52...Blade control board, 53...Groove, 54...
Lever, 55...Solenoid, 56...Spring, 5
7... Nail roll.

Claims (1)

[Scope of Claims] 1. A ratchet wheel which is fixed to a drive shaft and has an engagement recess on its periphery, and a claw arm which has a claw that can be engaged with the engagement recess of the ratchet wheel, and which swingably supports the drive shaft. a driving member rotatably supported by the claw arm; and means for engaging and disengaging the claw arm;
In the clutch device in which the driving member is drivingly connected to the driven member, one or more blades are supported to be swingable in the radial direction within a predetermined range on a blade support plate arranged in a fixed position. , a means for swinging the blade forms a clutch disengagement means, and the blade has an outer circumferential surface forming an arcuate surface centered on the drive shaft at a radially outermost position. , the outer peripheral surface forms a cam surface with which a claw roller provided near the claw of the claw arm comes into contact, and the means for swinging the blade includes a roller provided at the free end of the blade and a cam surface in which the roller is contacted. a blade control plate having an engaging groove and rotatably supported around the drive shaft; a solenoid connected to the blade control plate and rotating in a clutch disengagement direction; and a spring that is coupled to provide a force counteracting the force of the solenoid, and the groove of the blade control plate is formed as a groove extending in a direction oblique to the radial direction of the drive shaft; As the blade oscillates in the radial direction together with the roller that engages with the groove due to rotation, the pawl roller that contacts the outer circumferential surface of the blade is moved in the radial direction, and the pawl arm engages with the pawl wheel and is moved in the radial direction. A clutch device characterized by a disengagement movement. 2. The clutch device according to claim 1, wherein the driven member is drivingly connected to a scanning optical device that is reciprocated. 3. The scanning optical device includes a fixed document table, an optical device including an illumination device and a mirror that are reciprocated with respect to the document table, and a transmission device having a wire connected to the optical device and driving the optical device. A patent characterized in that the transmission pulley has a transmission pulley that drives the wire, and a return motor that drives the wire in a direction opposite to the transmission pulley, and the transmission pulley is drivingly connected to the drive member having the claw arm. Clutch device according to claim 2.