JPH04303832A - Optical system driving device - Google Patents

Abstract

PURPOSE:To provide an optical system driving device in which limitation on acceleration due to the weak driving force of a pulse motor compared with another motor can be solved and provided with fast and superior characteristic with high accuracy in the optical system driving device setting the pulse motor used in a copying machine and an image reader as a driving force source. CONSTITUTION:The pulse motor 1 is driven by a control pulse when an original is read, and read scanning is performed, and also, a DC motor 5 is set free. The DC motor 5 is driven by a control current in return to a scan origin, and the pulse motor 1 is set free. By providing the DC motor as the driving force source in the return to the scan origin as stated above. it is possible to perform scan with high accuracy by the pulse motor in the reading of the original, and to increase the number of times of scan per unit time by performing return scan by the DC motor at high speed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system drive device used in a copying machine or an image reading device.

0002

2. Description of the Related Art In recent years, optical system drive devices have become faster and more accurate with the advancement of office automation. In the case of an optical system driving device that requires high precision, a pulse motor is generally used in many cases.

A conventional optical system driving device will be explained below. FIG. 2 shows a perspective view of a conventional optical system driving device. In FIG. 2, reference numeral 13 denotes a first movable reflecting mirror, which reflects and bends the light ray PQ from the image into a light ray QR, which is directed toward the second movable reflecting mirror 14. This situation is shown in FIG. 3 as a cross-sectional view from the side. The light ray QR is bent in the direction of the light ray RS by the second movable reflecting mirror 14, and is further bent into the direction of the light ray ST.
bent in the direction of An optical sensor (not shown) is arranged in the direction of the light beam ST, and receives the light beam ST and converts the brightness of the image into an electrical signal. Further, a reflecting mirror may be arranged in place of the optical sensor, and the light beam ST may be directly projected onto the photoreceptor to form an electrostatic latent image on the photoreceptor. First movable reflector 1
3 is a guide rail 15,
15' so that it can make reciprocating parallel movements in the directions of arrows X and Y. Similarly, the second movable reflecting mirror 14 is guided by rollers 14a, 14a' so that it can reciprocate and parallel move in the directions of arrows X and Y on guide rails 15 and 15'. Further, the first movable reflecting mirror 13 is connected to a wire 21, which will be described later, at wire fixing parts 13c at both ends thereof, and the second movable reflecting mirror 14 has pulleys 16 at both ends thereof.
, 16'. On the other hand, a pulse motor 1 having a first drive pulley 2 drives a first driven pulley 4 via a belt 3, and drives a drive shaft 9 and wire drums 22, 22'.
to drive. Fixed pulleys 17, 17', 18, 18', 19, 19' having fixed shafts in the housing (not shown) are also provided.
, 20, 20' and wire fixing devices 23, 23' which are also fixed to the housing. The wires 21, 21' start from the wire fixing devices 23, 23', are wound around the outer periphery of the pulleys 16, 16' of the second movable reflector 14, and then are connected to the first movable reflector at the wire fixing parts 13c, 13c'. 13, fixed pulleys 19, 19', 20,
After passing through the wire drums 20, 20' and being wound several times around the wire drums 22, 22', the fixed pulleys 20, 20', 18, 18' are wound around the pulleys 16, 16' again, and the fixed pulleys 17,
It is connected to the wire tension spring 24 via 17'. The wire tension spring 24 is for ensuring a predetermined tension on the wire.

With the above configuration, as shown in FIG. 3, when the first movable reflector 13 moves by one dimension, the second movable reflector 14 moves by 1/2 the dimension, so that the incident light is reflected from the point P. The length of the ray PQRST is always kept constant. That is, when the pulse motor 1 rotates, the first movable reflecting mirror 13 and the second movable reflecting mirror 14 scan the document surface in one direction. When the scanning is completed, the pulse motor 1 rotates in the opposite direction at high speed to return the first movable reflecting mirror 13 and the second movable reflecting mirror 14 to the scanning origin position at high speed.

[0005]

As explained above, in the conventional optical system driving device, only a pulse motor was used as a driving power source. Originally, a pulse motor was made to rotate by a fixed angle for each pulse of an electric signal, so it is convenient for synchronizing the movement of the optical system with the operation of other devices. However, while pulse motors have good rotational accuracy, they have the disadvantage of low driving torque. Therefore, although the configuration of the conventional optical system drive device described above has good document scanning accuracy, it has the problem that the driving torque for returning to the scanning origin position at high speed is insufficient, making it impossible to return to the scanning origin position at high speed. Ta.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide an optical system driving device that can be operated at high speed.

[0007]

[Means for Solving the Problem] In order to achieve this object, an optical system driving device of the present invention includes a guide rail, a first movable reflecting mirror supported so as to be movable in parallel on the guide rail, and a second movable reflecting mirror. a reflecting mirror, the first movable reflecting mirror and the second movable reflecting mirror;
a drive device for performing parallel movement with the movable reflecting mirror; a pulse motor connected to a drive shaft of the drive device; and a second motor having a larger driving force than the pulse motor connected to the drive shaft in parallel with the pulse motor. The configuration is such that they are connected.

[0008]

[Operation] With this configuration, when reading a document, the pulse motor is driven with high precision, and when returning to the scanning origin, the second motor other than the pulse motor, which has a larger driving force than the pulse motor, is driven at high speed, thereby reducing the The number of scans can be increased.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment according to the present invention, and the same numbers are used for parts common to the conventional example, and explanations thereof will be omitted.

In FIG. 1, a second driven pulley 8 is provided coaxially with a drive shaft 9 driven by a pulse motor 1.
It is driven by a second drive motor 5 via a second drive pulley 6 and a second drive belt 7. As the second drive motor 5, a motor having a larger driving force than the pulse motor 1 is selected in advance and used. As mentioned above, since the pulse motor 1 is driven based on the pulse input of the electric signal, the drive circuit 33 that generates the pulse signal is required to drive the pulse motor. Further, the second drive motor 5 is a general DC motor with a large driving force.
Since a motor or an AC motor is used, a second motor drive circuit 34 having a power capacity to drive the second drive motor 5 is required.

Further, a scan end detection sensor 30 is provided at the end position of the scan of the image in the direction of arrow Y of the first movable reflecting mirror 13, and a scan end signal 31 from the scan end detection sensor 30 is input to a switching control circuit 32. has been done. Switching control circuit 32
When the scan end signal 31 arrives, the pulse motor drive circuit 33 is switched to the second motor drive circuit 34.

In the above configuration, first, the pulse motor drive circuit 33 operates to drive the pulse motor 1, move the first movable reflecting mirror 13 and the second movable reflecting mirror 14 in the direction of arrow Y, and scan an image. . When the first movable reflecting mirror 13 reaches the end position of image scanning, the scan end detection sensor 30 operates and sends the scan end signal 31 to the switching control circuit 32, which controls the operation of the pulse motor drive circuit 33 to the second motor drive circuit 34.
Switch to As a result, the first movable reflecting mirror 13 and the second movable reflecting mirror 14 return in the direction of arrow X at high speed. When the first movable reflecting mirror 13 and the second movable reflecting mirror 14 return more quickly during image scanning, the number of scans per unit time can be increased and high-speed reading becomes possible.

[0014]

Effects of the Invention As described above, the present invention provides a drive shaft that drives a first movable reflecting mirror and a second movable reflecting mirror, in which a pulse motor operated by a pulse signal and a second drive motor with a large driving force are connected in parallel. By connecting the first movable reflector and the second movable reflector during image scanning, a pulse motor with high rotational synchronization accuracy is connected to the
Since the movable reflecting mirror is driven and the second drive motor with a large driving force is used to return the mirror during the return operation, the scanning accuracy is good and the return time can be shortened, making it possible to read images at high speed.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an optical system driving device in a first embodiment of the present invention.

[Fig. 2] Perspective view of a conventional optical system drive device

[Fig. 3] Vertical cross-sectional view of the first movable reflecting mirror and the second movable reflecting mirror in Fig. 2.

[Explanation of symbols]

1 Pulse motor 5 Second motor 9 Drive shaft 13 First movable reflector 14 Second movable reflector 15,15' guide rail 30 Scan end detection sensor 32 Switching control circuit 33 Pulse motor drive circuit 34 Second motor drive circuit

Claims (2)

[Claims] 1. A guide rail, a first movable reflective mirror and a second movable reflective mirror supported so as to be movable in parallel on the guide rail, and parallel movement of the first movable reflective mirror and the second movable reflective mirror. An optical system drive device comprising: a drive device for performing movement; a pulse motor connected to a drive shaft of the drive device; and a second motor having a larger driving force than the pulse motor connected to the drive shaft in parallel with the pulse motor. 2. A pulse motor drive circuit that drives a pulse motor, a second motor drive circuit that drives a second motor,
It has a switching control circuit that switches between the operation of the pulse motor drive circuit and the operation of the second motor drive circuit, and a scan end detection sensor that detects the end position of the scan of the first movable reflecting mirror, and the pulse motor drive circuit operates. The pulse motor is the first
The movable reflector and the second movable reflector are caused to scan, and the scan end detection sensor sends a scan end signal to the switching control circuit, whereby the operation of the pulse motor drive circuit is switched to the operation of the second motor drive circuit. The first motor is driven by two motors.
The optical system driving device according to claim 1, wherein the movable reflecting mirror and the second movable reflecting mirror are operated to return.