JPH0337187B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a scanning optical system drive mechanism.

Prior Art In general, a scanning optical system drive mechanism scans and moves a first optical system consisting of a light source and a first mirror, and a second optical system consisting of second and third mirrors in a fixed direction at a speed ratio of 2:1. There has been provided a device in which image exposure is performed on an image receptor using a photoreceptor.

Specifically, as shown in Fig. 1, the scanning optical system is driven by a wire on only one side, that is, one wire 2 wound around a drive pulley 1 is stretched around a rotatable fixed pulley 3. The wire 2 is fixed to the first optical system 10 and stretched over a movable pulley 4 rotatably provided to the second optical system 19, and then one end 2a is fixed to a base plate (not shown) or the like, and the other end of the wire 2 is rotatably provided. After being stretched around the fixed pulley 5 and the movable pulley 4, the other end 2b is fixed to a base plate or the like. In this case, by rotating the drive pulley 1 in the counterclockwise direction, each pulley 3, 4, 5
is rotated clockwise and the wire 2
moves clockwise, the first optical system 10 scans in the direction of arrow A, and the second optical system 19 scans in the same direction together with the movable pulley 4 at a speed ratio of 2:1. In order to restore the first optical system 10 and the second optical system 19, it is sufficient to switch the rotation direction of a drive motor (not shown) and rotate the drive pulley 1 clockwise.

However, since the optical system is wire-driven only on one side of the scanning path, inertia acts on the left and right sides of the optical system when the first and second optical systems change direction, start, stop, etc. A difference occurs between the force and the moment of the driving force, which causes a tilt in the optical system. Therefore, not only is a large torque required to drive the optical system, but also vibrations occur due to the above-mentioned inclination and deflection, and as a result, high-speed scanning is difficult.

In addition, in this device, it is necessary to reliably guide the optical system in order to prevent tilting of the optical system as much as possible, and for this purpose, as shown in FIGS. 2 and 3, a light source and a first mirror 11 (not shown) are provided. One side (wire drive side) of the scanner 12 of the first optical system 10 equipped with
It is necessary to adopt a highly rigid structure in which the optical system is supported by a slide shaft 13 extending in the scanning direction via a slide bearing 14, which leads to an increase in cost and becomes a factor in increasing the weight of the optical system. The other side of the scanner 12 is placed on a slide shaft 15 via a wear-resistant slide member 16.

On the other hand, in order to eliminate the drawbacks of such a one-sided wire drive system, as shown in FIGS. 4 and 5, two
A method is provided in which wire drive pulleys 7, 7 are used to drive wires on both sides of the optical system. In the one shown in FIG. 4, a support shaft 6 is provided in the center of the scanning path, and a first wire 8 and a second wire 9 are wound around drive pulleys 7, 7.
One side is stretched around rotatable fixed pulleys 3, 3,
Fixed to the first optical system 10 and the second optical system 1
After the wires 8 and 9 are stretched around movable pulleys 4 and 4 that are rotatably provided at the wires 9, one ends 8a and 9a are fixed to a base plate (not shown), etc., and the other end of the wires 8 and 9 is stretched around the rotatable fixed pulleys 5 and 5. After being stretched around the movable pulleys 4, 4, the other ends 8b, 9b are fixed to a base plate or the like. In this case, by rotationally driving the support shaft 6 in the counterclockwise direction, the first optical system 10 and the second optical system 19 are each scanned in the direction of the arrow (A) at a speed ratio of 2:1.

In the one shown in FIG. 5, the support shaft 6 is installed at the end of the scanning path, and the middle part of the first wire 8 is wound around the drive pulley 1, so that the second wire 9 is driven to move. Basically, the configuration and operation are similar to those in FIG. 4.

However, in these devices, it is necessary to increase the rigidity of the support shaft 6 in order to prevent unbalance of operation on both sides of the optical system due to twisting of the support shaft 6. Requires large torque. In addition, since the pulleys 7, 7 are connected by the support shaft 6 that crosses the scanning path, the pulleys 7, 3, 4, and 5 are necessarily installed in the vertical direction, and the first wire 8, the second wire 9 must be stretched twice on the front side and the rear side, making the wire tensioning work extremely complicated.

Purpose The present invention has been made in view of the above points, and by adopting a wire tensioning method that enables efficient and well-balanced driving, the scanning movement of an optical system can be made stable at high speed. The object of the present invention is to provide a scanning optical system driving mechanism that can perform the following steps.

Summary In order to achieve the above object, the present invention provides the first
A scanning optical system drive mechanism that moves a scanning optical system that exposes an image onto an image receptor by scanning an optical system and a second optical system in one direction at a speed ratio of 2:1, the first optical system a wire fixed end provided on both sides of the second optical system, a movable pulley provided on both sides of the second optical system, a common pulley provided at the center position in the width direction of the scanning path, and a wire fixed end provided on both sides of the second optical system; fixed pulleys provided on both sides in the width direction of the scanning path, one end of which is wound and fixed around the common pulley, and connected to one wire fixed end of the first optical system via the fixed pulley on one side of the scanning path. After being fixed, a first scan wire whose other end is fixed to the fuselage frame via one movable pulley of the second optical system, and a first scan wire whose one end is wound and fixed to the common pulley and the other end of the scanning path The second optical system is fixed to the other wire fixed end of the first optical system via the fixed pulley on the side thereof, and the other end of the second optical system is fixed to the fuselage frame via the other movable pulley of the second optical system. The present invention is characterized by comprising a scan wire and a drive means for rotating the common pulley.

Embodiment FIG. 6 schematically shows an electrophotographic copying machine equipped with a scanning optical system drive mechanism according to the present invention. Copy machine body 2
A photoreceptor drum 21 that can be rotated counterclockwise is disposed approximately in the center of 0, and around it are a main eraser lamp 22 and a sub-charging charger 2.
3 sub eraser lamp 24, main charger 25, microtoning type developing device 2
6, a transfer charger 27, a copy paper separation charger 28, and a blade type cleaning device 29. The photosensitive drum 21 has Cds/
Equipped with nCdCO ₃ resin binder photoreceptor,
The photoreceptor is sensitized by passing through the eraser lamps 22, 24 and chargers 23, 25, and receives image exposure from the optical system 40.

The optical system 40 is installed below the original glass 39 to be able to scan the original image, and includes a first optical system 41 consisting of a light source (not shown) and a first mirror 42, and a second optical system 41 consisting of a second mirror 51 and a third mirror 52. 2 optical system 5
0, a transmission projection lens 58, and a fixed mirror 59. Note that the first optical system 41 moves to the left at a speed of (v/n: where n: copy magnification) with respect to the circumferential speed v of the photosensitive drum 21 (constant regardless of whether the magnification is the same or variable magnification). , the second optical system 50 moves to the left at a speed of (v/2n).

On the other hand, paper feed cassettes 30 and 31 that can automatically feed paper are installed on the left side of the copying machine main body 20, and the copy paper conveyance path includes roller pairs 32, 33, 34, a guide plate 35, a conveyance belt 36, and a fixing device. 37, and a pair of discharge rollers 38.

The copying machine main body 20 also includes an optical system 40, a photosensitive drum 21, a developing device 26, and a cleaning device 29.
an upper unit including paper feed sections 30, 31, transfer/separation chargers 27, 28, fixing device 36,
It is divided into a lower unit containing conveyance path components,
The upper unit is hingedly supported by a support shaft (not shown) provided on the left side of the developing device 26, and can be opened upward. Jam removal, various maintenance, etc. can be performed with the upper unit open.

FIG. 7 shows a first embodiment of the scanning optical system drive mechanism according to the present invention.
Wires 70a, 71a, second wires 70b, 71
b extend on both sides of the scanning path, and drive the first optical system 41 and the second optical system 50 for scanning and returning.

The common pulley 60 is installed at the widthwise center of the scanning path in the scanning direction (A) side of the scanning path, and is connected directly to the motor that can rotate in forward and reverse directions or indirectly to the motor through a clutch that can switch between forward and reverse rotations. It is connected to and can be rotated in either forward or reverse directions.

First wires 70a, 71a, second wire 70
b, 71b are functionally scan wires 70a,
70b and return wires 71a and 71b. The scan wires 70a and 70b are fixed at one end to the common pulley 60, wound slightly counterclockwise, and stretched around fixed pulleys 61a and 61b rotatably provided on the frame 80, and then connected to both sides of the scanning path. After being extended and fixed to fixed pieces 44a and 44b on both sides of the scanner 43 of the first optical system 41, and attached to movable pulleys 54a and 54b rotatably provided on both sides of the scanner 53 of the second optical system 50, , and the other ends thereof are fixed to brackets 81a and 81b attached to the frame 80. In addition, the return wires 71a and 71b are fixed at one end to the common pulley 60, wound clockwise a necessary number of times, and stretched around fixed pulleys 62a and 62b rotatably provided on the frame 80, and then stretched on both sides of the scanning path. It extends over the fixed pulleys 63a, 63b rotatably provided on the frame 80 and is folded back, and is further stretched over the movable pulleys 54a, 54b and folds back, and is rotatably attached to the frame 80. It extends inward via provided idler pulleys 64a and 64b, and is fixed to both ends of a tension spring 72.

On the other hand, the scanners 43 and 53 are connected to the frame 80.
A stainless steel plate having a smooth surface is supported on both sides of the frame 80, and is attached to rail portions 82a and 82b with the upper part of the frame 80 bent inward, as shown in FIGS. 8, 9, and 10. The scanner 4 is placed on the slide members 45a and 45b made of material etc.
Teflon-based resin with a low coefficient of friction attached to the lower surfaces of both sides of 3, for example, Western Bear, Rulon Kogyo Co., Ltd.
Slide members 46a and 46b made of Rulon J (coefficient of friction 0.06 to 0.08) made by Manufacturer Co., Ltd. are opposed to each other.

In the above configuration, in order to cause the first optical system 41 and the second optical system 50 to scan, the common pulley 60 is rotated in the clockwise direction. That is, as the common pulley 60 rotates clockwise, the scan wires 70a, 70b are wound around the common pulley 60, and each pulley 61a, 61b, 54a, 54
b is driven to rotate, and the first optical system 41 and second optical system 50 scan in the direction of arrow (A) at a speed ratio of 2:1. At the same time, return wire 7
1a and 71b are pulled out from the common pulley 60 by the spring force of the tension spring 72.

The return of the first optical system 41 and the second optical system 50 is performed by driving the common pulley 60 reversely in the counterclockwise direction. That is, as the common pulley 60 rotates counterclockwise, the returns 71a and 71b are wound around the common pulley 60 against the spring force of the tension spring 72.
Each pulley 62a, 62b, 63a, 63b, 54
a, 54b, 64a, and 64b are driven to rotate, and the first optical system 41 and second optical system 50 are rotated in the opposite direction (A).
Move back in the direction. At the same time, scan wire 7
0a and 70b are pulled out from the common pulley 60.

In the above operation, the first optical system 41 and the second optical system 50 are connected to the first wires 70a and 70 on both sides of the scanning path.
1a and the second wires 70b, 71b, equal driving force and inertial force act on both sides of the optical systems 41, 50, and the optical systems 41, 50 are not tilted or twisted. Further, the guide mechanism can be considerably simplified and lightened as shown in FIGS. 8 to 10, and as a result, high-speed scanning is possible. Moreover, the common pulley 60 is installed horizontally, and the other pulleys 61a, 63
Since wires 70a, 54a, etc. are also installed in the horizontal direction, it is necessary to stretch the wires 70a, 70b, 71a, 71b on the front and rear sides of the scanning path.
The wire can be stretched on a flat surface, and the wire tensioning work is rather simplified compared to the conventional technique shown in FIGS. 4 and 5.

FIG. 11 shows a second embodiment, in which a common pulley 60
is installed vertically and uses two wires. The first wire 73a and the second wire 73b are each wound around a common pulley 60.
One side pulled out in the counterclockwise direction from 0 is stretched over fixed pulleys 61a and 61b, and the first optical system 41
It is fixed to both sides of the optical system 50, and after being stretched over movable pulleys 54a and 54b provided in the second optical system 50, it is fixed to the frame. Wires 73a, 73b
The other one is the fixed pulley 62a, 62b, 63a, 6
3b, and after being stretched around movable pulleys 54a and 54b, it is fixed to the frame.

In this embodiment, the operation of the optical system is
This is the same as in the embodiment, and as the common pulley 60 rotates counterclockwise, the first optical system 41 and the second optical system 50 scan in the direction of the arrow (A) at a speed ratio of 2:1. , the common pulley 60 is returned to its original position by rotating counterclockwise.

In addition, in the first embodiment, since the common pulley 60 is installed horizontally, the pulleys 61a on both sides,
61b etc., but by installing the common pulley 60 vertically as in this second embodiment and appropriately tilting each axis of the pulleys 61a, 61b, 62a, 62b on both sides, the wires 73a, 73b etc.
can be stretched at the same height, and the pulley 63
There is no difference in level between the movable pulleys 54a and 54b and the movable pulleys 54a and 54b.

Alternatively, the first wires 73a and 73b may be further divided into two, a scan wire and a return wire as in the first embodiment, and the ends of each wire may be wound and fixed around the common pulley 60. good. In other words, the first embodiment may also have a structure in which the scan wires 70a, 70b and the return wires 71a, 71b are made into one wire and the intermediate portion is wound around the common pulley 60, as in the second embodiment.

The above embodiment is applied to an electrophotographic copying machine, but it is also possible to scan a document with a scanning optical system.
Needless to say, the present invention can also be applied to facsimiles and document reading devices that expose image receptors such as CCDs and photodiode arrays.

In addition, in the above embodiment, a return wire wound around a common wire is used for the return movement of the optical system, but this return wire is simply used to return the optical system to the position before the scanning movement. Therefore, other drive methods may be used.

As is clear from the above description, the present invention adopts a method of driving wires on both sides of the scanning path, and also moves the first and second scan wires extending on both sides of the scanning path to the central position in the width direction of the scanning path. Since the optical system is wound and fixed around a common pulley located at No tilting or twisting of the system occurs. As a result, the optical system can be driven efficiently and with good balance, and stable scanning movement of the optical system can be expected at high speed.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a conventional scanning optical system drive mechanism, Figs. 2 and 3 are a plan view and a front view showing the guide portion thereof, and Figs. 4 and 5 are other examples of the conventional scanning optical system drive mechanism. FIG. FIG. 6 is a schematic front view of an electrophotographic copying machine equipped with a scanning optical system drive mechanism according to the present invention. 7 to 10 show a first embodiment of the scanning optical system drive mechanism according to the present invention, and FIG.
The figure is a perspective view, FIG. 8 is a plan view of the guide part, and FIGS. 9 and 10 are a front view and a side view thereof. FIG. 11 is a perspective view showing the second embodiment. 21... Photosensitive drum, 40... Scanning optical system,
41...first optical system, 43...scanner, 50...
...Second optical system, 53...Scanner, 54a, 54
b...Movable pulley, 60...Common pulley, 61
a, 61b, 62a, 62b, 63a, 63b...
... Fixed pulley, 64, 66 ... Drive pulley, 70
a, 71a, 73a...first wire, 70b, 7
1b, 73b...second wire.

Claims (1)

[Scope of Claims] 1. A scanning optical system drive mechanism that drives a scanning optical system that exposes an image onto an image receptor by scanningly moving a first optical system and a second optical system in one direction at a speed ratio of 2:1. A wire fixed end provided on both sides of the first optical system, a movable pulley provided on both sides of the second optical system, and a common pulley provided at a central position in the width direction of the scanning path. a fixed pulley provided on both sides of the common pulley in the width direction of the scanning path; A first scan wire is fixed to one wire fixed end of the optical system, and the other end is fixed to the aircraft frame via one movable pulley of the second optical system, and one end is wound around the common pulley. The wire is fixed once and fixed to the other wire fixed end of the first optical system via the fixed pulley on the other side of the scanning path, and then the other end is fixed via the other movable pulley of the second optical system. A scanning optical system drive mechanism, comprising: a second scan wire fixed to a body frame; and a drive means for rotating the common pulley. 2. The scanning optical system drive mechanism according to claim 1, wherein each of the pulleys is provided horizontally on a vertical support shaft.