JPH09149204A - Copying machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute appropriate speed control by setting the tension of a scanner driving belt to be a movable system, suppressing the temporary change of a scanner sliding load at the time of returning a scanner and executing a reciprocal operation on the scanner as a designated velocity drawing. SOLUTION: A tension pulley giving tension to the driving belt 3 is not fixed and tension is given to the movable system with a spring 9 which movably supports a movable tension pulley 8. The temporary tension change occurring at acceleration initial time at the time of returning the scanner and at deceleration initial time for stopping the scanner, are absorbed by the spring 9 which movably supports the movable tension pulley 8, and it is matched with the velocity drawing without disturbing control. Since the reciprocal operation of the scanner is executed as the designated velocity drawing, load fluctuation occurring during the scan operation can be suppressed and stable scanner driving is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, and more particularly to a scanner device in the copying machine.

[0002]

2. Description of the Related Art In a slit exposure type copying machine, a scanner control of a copying machine is such that a document having an image surface facing down is placed on a contact glass and the projected image is scanned by a scanner from the bottom. An image is formed on the photoconductor. The scanner is generally driven by a motor, and recently, it is controlled by a microcomputer. The control mainly includes open loop control and feedback control. In the case of a stepping motor, the former control, DC
In the case of a servo motor, the latter control is used.

[0003]

In the high-speed copying machine, not only the original reading speed becomes high, but also the return speed needs to be very high. In order to increase the return speed, it is necessary to increase the acceleration at the time of return and the deceleration for stopping. A temporary change in tension of a belt or a wire for driving at the start of these operations occurs, and speed control is disturbed. As a result, the reference velocity diagram of the reciprocating operation is no longer satisfied, and the stop position varies and the scanner vibrates.

Further, since the acceleration and deceleration at the time of return are large, a very large current is required for the motor,
The motor heats up and the control is delayed due to torque reduction. As a result, the reference speed diagram of the reciprocating operation is no longer satisfied, and the stop position varies and CPM down occurs.

The present invention solves the above-mentioned drawbacks of the prior art, suppresses the fluctuation of the scanner sliding load during the operation of the scanner, and suppresses the heat generation of the motor, thereby performing an appropriate speed control. The purpose of the invention is to provide a scanner control device capable of performing the above-mentioned operation.

[0006]

According to a first aspect of the present invention, there is provided a scanner (reciprocating member) for scanning an original image, and a driving unit for reciprocating the scanner by a motor. In a copying machine that transmits rotation to a scanner drive pulley that drives the scanner through a scanner drive belt, the tension of the scanner drive belt is made movable so that the scanner temporarily slides during acceleration and deceleration during scanner return. The feature is that the change in load is suppressed and the scanner is reciprocated according to a designated velocity diagram.

According to a second aspect of the present invention, in the copying machine according to the first aspect, the sliding load is increased at the time of scanner return to reduce the current flowing through the motor to suppress heat generation of the motor, and a designated speed diagram. The feature is that the scanner is reciprocated as it is.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of the essential parts for explaining an embodiment of a scanner control apparatus according to the present invention.
3 is a block diagram showing an embodiment of a digital servo control device for driving a scanner motor (DC servo motor). The digital servo control device obtains a reference velocity diagram as shown in FIG. is there. In FIG. 1, 1 is a scanner drive motor, 2 is a scanner traveling body, 3 is a drive belt, 4 is a scanner traveling body drive wire,
5 is a motor pulley, 6 is a scanner scanning body driving pulley, 7
Is a fixed tension pulley, 8 is a movable tension pulley,
A reference numeral 9 designates a spring for movably supporting the movable tension pulley 8. In the present invention, in contrast to the conventional one in which the drive between the motor drive section 1 and the scanner traveling body section 2 is performed by means of the belt 3. , The tension pulley that applies tension to the belt 3 is not fixed, but the tension is movably applied by the spring 9, and a temporary change in tension occurs at the initial stage of acceleration at the scanner return and the initial stage of deceleration for stopping the scanner. Is absorbed by the spring 9 so as to match the velocity diagram shown in FIG. 3 without disturbing the control.

Further, by increasing the tension of the belt 3 only during deceleration at the time of return, deceleration control is enhanced so that an electric current flowing through the motor is prevented from flowing more than necessary, heat generation of the motor is suppressed, and torque is reduced. Is suppressed as much as possible to prevent the control delay due to the torque change, and to match the speed diagram without disturbing the control.

FIG. 2 shows the scanner motor (D
11 is a block diagram for explaining an example of a digital servo control device for driving a C motor, in which 11 is a DC servo motor (corresponding to the scanner motor 1 shown in FIG. 1), 1
2 is a rotary encoder, 13 is a frequency divider, 14 is PWM
The signal generator, 15 is a microcontroller,
The servomotor 11 operates as shown in FIG.
The reference velocity diagram (reciprocating velocity diagram of the scanner traveling body 2) shown in is obtained.

In FIG. 2, the DC servo motor 11 is
The current speed is measured by the encoder 12 driven by the H-bridge circuit composed of Q _{1 to} Q ₄ and its peripheral circuits and attached to the DC servomotor, and the feedback pulse from the encoder 12. The microcontroller (CPU) 5 performs a PI operation on the measured speed signal, and a PWM signal that changes the duty ratio according to the operation result, and P ₀ and P ₁ that determine the operation of the scanner.
Is output. Table 1 shows a logical table of the output ports P ₀ and P ₁ .

[0012]

[Table 1]

[0013]

According to the present invention, there is provided a scanner (reciprocating member) for scanning an original image and a driving means for reciprocating the scanner by a motor, and the rotation of the motor drives the scanner. In a copying machine in which a belt is transmitted to a scanner drive pulley, the tension of the scanner drive belt is not fixed but is made movable, and the scanner is temporarily slid during deceleration for acceleration and stop operation at the time of scanner return. Since the load change is suppressed and the scanner is made to reciprocate according to the designated speed diagram, it is possible to suppress the load fluctuation that occurs during the scanning operation.
The scanner can be driven according to the velocity diagram as shown in (3), and stable scanner driving can be performed.

According to a second aspect of the present invention, in the copying machine according to the first aspect, the sliding load is increased at the time of the scanner return to reduce the current flowing through the motor to suppress the heat generation of the motor, and the designated speed diagram. Since the scanner is made to reciprocate as described above, heat generation can be suppressed by reducing the motor current at the time of scanner return, and the scanner can be driven according to the velocity diagram as shown in FIG. Can drive the scanner.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram for explaining an embodiment of a scanner device according to the present invention.

FIG. 2 is a block diagram for explaining control of a scanner drive motor.

FIG. 3 is a diagram showing a reference velocity diagram of reciprocal movement of a scanner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scanner drive motor, 2 ... Scanner traveling body, 3 ... Drive belt, 4 ... Scanner traveling body drive wire, 5 ... Motor pulley, 6 ... Scanner scanning body drive pulley, 7 ... Fixed tension pulley, 8 ... Movable tension pulley, 9 ... a spring that movably supports the movable tension pulley 8, 11 ... DC
Servo motor, 12 ... Rotary encoder, 13 ... Divider, 14 ... PWM signal generator, 15 ... Micro controller.

Claims (2)

[Claims] 1. A scanner for scanning an original image,
In a copying machine which has a driving means for reciprocating the scanner by a motor and transmits the rotation of the motor to the scanner driving pulley via the scanner driving belt, the tension of the scanner driving belt is made movable to allow the scanner to move. A copying machine characterized in that a temporary change in scanner sliding load during acceleration and deceleration during return is suppressed, and the scanner is reciprocated according to a specified speed diagram. 2. The copying machine according to claim 1, wherein when the scanner returns, the sliding load is increased to reduce the current flowing through the motor to suppress heat generation of the motor, and the scanner reciprocates according to a designated speed diagram. A copying machine characterized by being operated.