JPS5953527B2 - copying device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for driving an optical system of a copying machine.

In order to reduce or enlarge the size of the original in a slit exposure type copying machine, a first scanning means is used along the platen surface a as shown in FIG. 1, where the reduction ratio is m. In a scanning device of the type in which the second scanning means d scans the first scanning means in synchronism with the first scanning means in order to keep the optical distance between the second scanning means d and the first scanning means constant, the optical distance between the first scanning means For scanning devices in which the scanning means is scanned at a speed 1/m times the linear velocity of the photosensitive surface, or the lens e shown in FIG. 2 is scanned optically parallel to the platen surface a, the photosensitive surface It is necessary to scan the lens e at a speed 1/(m+1) times the linear velocity of f.

Conventionally, this has been achieved by providing a plurality of output shafts with different gear ratios to obtain a scanning speed corresponding to the magnification for a single drive source, and selecting the required output shaft using a clutch means. In addition, for high-speed recovery of the scanning system for multiple scans, a clutch means is connected to the output shaft that rotates in the opposite direction to the driving direction of the scanning system, and the scanning J system can be activated in a short time. A method of reinstatement has been taken.

In order to increase the number of copies per unit time using the conventional method, if the linear velocity of the photoreceptor is constant, the scanning system must be restored in as short a time as possible. This large acceleration causes harmful vibrations in the scanning system, impairing the resolution of the image on the photoreceptor and other problems.In order to suppress the occurrence of the above vibrations, the magnitude of the acceleration must be reduced. In addition to this, it is also necessary that the change in acceleration l be as smooth as possible.

For this purpose, it is desirable to use a cam mechanism that can arbitrarily set the change in acceleration over time as a mechanism for driving the scanning system.

However, since the cam mechanism essentially has a constant driven amplitude, it is difficult to use it as a scanning system for a copying machine because the sizes of originals in a copying machine often vary. does not meet the demand for change.

' The present invention was made in view of the above circumstances, and
The purpose of this is to change the operating distance of the moving optical system by selecting drive pulleys with different diameters, and to correct the moving speed of the moving optical system by changing the number of revolutions of the cam to image the image on the photoreceptor. The objective is to enable high-speed scanning without compromising the resolution and resolution of images.

Hereinafter, the present invention will be explained with reference to FIG. 3 and subsequent figures.

1 in the drawing is a drum shaft, and a photoreceptor 37 is attached to this drum shaft 1.

A gear 20 is fixed to the drum shaft 1. gear 2
Gears 21a, 21b, 21c are meshed with gear 0, and gears 21a, 21b, 21 are engaged with gear shafts 23a, 23b, 23c of gear 2]A, 2lb, 2lc, respectively.
Clutches 22a, 22b, and 22c are provided to connect and disconnect the gear shafts 23a, 23b, and 23C. Hub 2 of clutches 22a, 22b, 22c
4a, 24b, 24c have actuating pieces 26a, 26b, 26
C are in mesh with each other, and these operating pieces 26a, 26b, 26
Clutches 22a, 22b, 2 are disengaged due to the action of the force ram 25 disposed on the drum shaft 1.
2c changes from the "disconnected" state to the "connected" state.

A sprocket 2 is attached to the gear shafts 23a, 23b, 23c.
7a, 27b, and 27c are attached.

An endless chain 2 is connected to the sprockets 27a, 27b, 27c and the sprocket 29 of the camshaft 28.
Further, the cam 3 is attached to the camshaft 28. In the drawing, reference numeral 4 denotes a cam follower having a swinging fulcrum P at its lower end, and this cam follower 4 is in sliding contact with the cam 3.

A shaft 29 is attached to the top of the cam follower 4, and the shaft 2
Pulleys 6a and 6b are rotatably provided at 9. In the drawing, 9a and 9b are retainers provided at the lower part of the support shaft 11 as a swing fulcrum P'', and these retainers 9a and 9b
are biased counterclockwise in FIG. 5 by springs 12a and 12b.

In the drawing, 13 is a rotating shaft, and drive pulleys 7a and 7b are fixed to this rotating shaft 13.

Cables 8a, 8b are wound around these driving pulleys 7a, 7b, and the free ends of the cables 8a, 8b are connected to the pulley 6.
a, 6b, and then locked to retainers 9a, 9b.

10a and 10b are cams that are fixed to the shaft 30 with a phase shift of 90 degrees;
By rotating the retainers 9a, 9b, the retainers 9a, 9b come into contact with or leave the abutment state, and have the function of applying tension to the cables 8a, 8b or eliminating this tension.

The rotating shaft 13 has pulleys 31a, 31b and a pulley 32.
a and 32b are fixedly installed.

Also, on the machine frame, pulleys 33a, 33b and pulley 34a,
Belts 35a, 35b are hung around the pulleys 31a, 31b and pulleys 33a, 33b, and a mirror 16 is attached to the belts 35a, 35b. In addition, pulleys 32a, 32b and pulleys 34a, 34b
Belts 36a and 36b are hung on the belts 36a and 36b.
, 36b are attached with mirrors 17.

In the drawing, reference numeral 15 denotes a return spring, one end of which is fixed to the rotating shaft 13, and the other end of the return spring 15 to the machine frame.

Next, the operation will be explained.

When the cam 3 rotates, the cam follower 4 moves in the direction of arrow 5 in Fig. 5.
It oscillates as shown.

At this time, the cam 10a pushes the retainer 9a, the cable 8a is stretched, and the cable 8b is stretched.
is provided by the tension spring 12b, which is weak enough not to come off the pulley 6b. In this state, the cam 3 rotates and the cam follower 4 swings, so that the pulley 6a applies tension to the cable 8a.

Therefore, the cable 8a wound around the pulley 7a
is fed out, the rotating shaft 13 is rotated by the pulley 7a against the return spring 15, and the pulleys 31a, 31
b and pulleys 32a, 32b are rotationally driven, mirrors 16, 17 constituting the moving optical system are moved so as to maintain conjugate positions, and a flowing image is formed on the photoreceptor 37 in synchronization with the speed of the surface of the photoreceptor 37. to project. Cam follower 4 is cam 3
After passing the high point, the cam follower 4 returns to its original position due to the tension of the cable 8a, and accordingly, the pulley 7a is also rotated in the direction opposite to the arrow 14 by the return spring 15, and the mirrors 16 and 17 return to their original positions.

When the shaft 30 is rotated half a rotation, the retainer 9b is rotated by the cam 10b.
The retainer 9a is loosened and the tension on the cable 8a is weakened, and the movement of the cam 3 is transmitted to the rotating shaft 13 by the pulley 7b.

In the above description, since the swinging process of the cam follower 4 is constant, the lengths of the cables 8a, 8b that are fed out are constant.

Therefore, when the shaft 13 is rotated by letting out the cable 8a from the pulley 7a, since the diameter of the pulley 7a is smaller than the diameter of the pulley 7b, the shaft 13 is rotated more than when the cable 8b is let out from the pulley 7b. Rotate. Therefore, in this case, the operating distance of mirrors 16 and 17 becomes long. In this way, by simply switching the cams 10a and 10b, it is possible to arbitrarily change the operating distances of the mirrors 16 and 17 while keeping the cam 3 the same. However, since the ratio of the diameters of the pulleys 7a and 7b is inversely proportional to the scanning speed of the mirror 16, the scanning speed may be adjusted by selecting the speed change of the transmission mechanism as necessary.

The selection of the gear ratio of the transmission mechanism is performed as follows.

That is, the rotation of the drum shaft 1 causes the gears 21a, 21b, and 21c to rotate via the gear 20.

As the drum shaft 1 rotates, the cam 25 rotates, and the cam 2
5 operates one of the actuating pieces 26a, 26b, and 26c, for example, the actuating piece 26a, and the clutch 22a is in the "contact" state, and the driving force of the drive shaft is transferred to the gear shaft 23a.
This is transmitted to the sprocket 29 via the sprocket 27a and the chain 2, and the cam 3 is rotated. Sprockets 27b and 27b for clutches 21b and 21C, respectively.
By changing the number of teeth of 27C or gear 21b,
Any gear ratio can be obtained by changing the number of teeth of 21C.

The present invention has been described in detail above, and includes a plurality of drive pulleys 7a and 7b of different diameters fixed to a rotating shaft 13 for moving two moving optical systems, and a plurality of drive pulleys 7a and 7b that are oscillated by the rotation of the force arm 3. A cam follower 4, a plurality of pulleys 6a, 6b of different diameters rotatably provided on the force follower 4, and pulleys 6a, 6 wound around the drive pulleys 7a, 7b.
Cables 8a, 8b hung on b, cable 8a,
a tension applying means for selectively applying tension to the cam 3;
The operating distance of the moving optical system can be changed by selecting drive pulleys with different diameters, and the resulting moving speed of the moving optical system can be corrected by changing the rotational speed of the cam. This makes it possible to perform high-speed scanning without impairing the resolution of the image on the photoreceptor.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a moving optical system, that is, a scanning optical system, for explaining a conventional copying apparatus, FIG. 3 is an explanatory diagram of the configuration of the present invention, and FIG. 4 is a configuration of the section 1V in FIG. 3. The explanatory diagram, FIG. 5, is an explanatory diagram of the configuration of section V in FIG. 3. 3 is a cam, 4 is a cam follower, 6a, 6b are pulleys, 7
a and 7b are drive pulleys, and 8a and 8b are cables.

Claims (1)

[Claims] 1. A plurality of drive pulleys 7a and 7b with different diameters are fixed to a rotating shaft 13 for moving the two moving optical systems, a cam follower 4 is oscillated by the rotation of the cam 3, and a cam follower 4 is rotatably provided to the cam follower 4. a plurality of pulleys 6a, 6b having different diameters, and a cable 8a wound around the drive pulleys 7a, 7b and hooked around the pulleys 6a, 6b.
, 8b, tension applying means for selectively applying tension to cables 8a and 8b, and speed change means for changing the number of rotations of cam 3.