JPH0534837A - Copying machine - Google Patents

Abstract

PURPOSE:To make a smooth and accurate stop at a reference position without any time loss by correcting the speed reduction start position in scanner backward movement to an optimum position. CONSTITUTION:A control part 22 calculates the number of encoder pulses corresponding to the scanner movement distance in forward movement from paper size and copy magnifications. Then the value is set in a 1st memory as a storage area in a RAM 28 and the initial value of the speed reduction start position in the backward movement corresponding to the value is set in a 2nd memory. A motor 16 is rotated forward, then reversed on the forward movement by a necessary distance, and braked when a scanner reaches the speed reduction start position. When the scanner is reduced in speed below a target speed, a 2nd counter in the RAM 28 counts the movement time of the scanner. Then the value in the 2nd memory is corrected according to the value of the 2nd counter unless the value of the 2nd counter is within a specific range after the motor 16 is stopped so as to correct the speed reduction start position in next-time backward movement.

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 copying machine having a reciprocating scanner for exposing and scanning an original.

[0002]

2. Description of the Prior Art In general, to move a scanner back, move the scanner at a fairly high speed to save time and increase copy speed. Therefore, in order to stop the scanner at the reference position smoothly and accurately, it is necessary to decelerate before the reference position. Therefore, conventionally, the deceleration start position is detected by a method of detecting with a sensor or a method of counting the pulses of an encoder that works in conjunction with a scanner driving motor, and deceleration is started at a fixed position.

[0003]

The moving distance required for deceleration varies each time due to variations in the load of the scanner drive system, etc. However, in the prior art, the deceleration start position of the scanner is always constant, so it is necessary for deceleration. Since it is necessary to set the deceleration start position at a position sufficiently distant from the reference position so as to ensure the maximum value of various moving distances, there is a problem that time loss is large. In order to absorb this loss of time, it was possible to delay the start of deceleration and complete deceleration faster, or to increase the speed of the scanner in the forward movement, but the former requires rapid deceleration, so the scanner needs to be decelerated. There is a problem in that unnecessary vibration is generated in the latter, and in the latter case, the speed of the entire copying machine has to be increased, which causes an excessive load on various parts.

Therefore, a main object of the present invention is to provide a copying machine which can be smoothly and accurately stopped at a reference position without loss of time when the scanner is moved back.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a scanner which reciprocates for exposing and scanning a document, a means for detecting a reference position of the scanner, and a scanner which is moved back at a first speed to return at a predetermined position. In a copying machine equipped with a first control means for switching to a second speed slower than the first speed and stopping the scanner at the reference position, means for detecting the time moved at the second speed when the scanner is moved back, and the detected time. The copying machine is characterized by further comprising second control means for changing a predetermined position for switching from the first speed to the second speed at the time of the next recovery movement.

[0006]

The time detecting means detects the time of movement at the second speed after deceleration of the scanner by counting encoder pulses, for example. The second control means moves the next deceleration start position away from the reference position when the detected time is shorter than a certain range, and brings the next deceleration start position closer to the reference position when the detected time is longer than the predetermined range, thereby decelerating start. Correct the position to the optimum position.

[0007]

According to the present invention, by correcting the deceleration start position when the scanner is moving backward to the optimum position, it is possible to smoothly and accurately stop at the reference position without loss of time. The above objects, other objects, features and advantages of the present invention are as follows.
It will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view showing a main part of a copying machine 10 of this embodiment. The copier 10 includes a scanner 12. The scanner 12 is mounted on a rail 14 arranged on an upper portion of a main body (not shown), and is reciprocally driven by a DC servo motor (hereinafter, simply referred to as “motor”) 16 in the direction of arrow A or B in the figure. .. It should be noted that the motor rotation direction during movement in the A direction, that is, forward movement is defined as normal rotation, and the motor rotation direction during movement in B direction, that is, during backward movement is defined as reverse rotation. An FG (not shown) is built inside the motor 16, and the FG generates a signal for detecting a rotation angle and a rotation speed. An optical sensor 18 for detecting a reference position (hereinafter, referred to as “MHP”) of the scanner 12 and a document leading end position (hereinafter, referred to as “MIP”) is arranged at a predetermined position, and the optical sensor 18 is operated. A light blocking plate 20 for causing the scanner 12 is provided on the side surface of the scanner 12. The sensor is turned on when the light blocking plate 20 blocks the optical sensor 18, and is turned off otherwise. And the scanner 12
A document table (not shown) made of transparent glass or the like is disposed above the table, and the document placed on the document table is exposed and scanned by the scanner 12. Further, a control unit (microcomputer system) 22 (FIG. 2), which will be described later, that controls the movement of the scanner 12 is arranged at a predetermined location (not shown).

When the power is turned on, the scanner 12 is set to the position shown in FIG.
Is moved from the right side in the direction B to the position where the optical sensor 18 is changed from OFF to ON, that is, the light shielding plate 20 is located at the optical sensor 18
It moves for a predetermined distance from the position where it was interrupted and stops. This is MHP. When the copy operation is started, the motor 16 rotates in the normal direction, and the scanner 12 moves from the MHP in the A direction. The position where the optical sensor 18 changes from ON to OFF, that is, the position where the light shielding plate 20 does not interrupt the optical sensor 18 is the MIP. After moving from the MIP by a distance according to the paper size and the copy magnification, the first Moves back in direction B at speed. Then, the optical sensor 18 becomes O again.
Apply the brake before changing from FF to ON, decelerate to the predetermined second speed, release the brake, continue moving, move the optical sensor 18 from OFF to ON again for a predetermined distance, and move to MHP. Stop at. The deceleration to the predetermined second speed may be completed even after the optical sensor 18 is turned on.

The scanner forward distance varies depending on the size of the paper and the copy magnification, and when the forward movement time is short and when the forward movement time is long, a difference in acceleration time of the scanner 12 causes a difference in speed when the deceleration start position is reached. At the start of copying, the deceleration start position is initialized. The movement of the scanner 12 is controlled by the control unit (microcomputer system) 22 as shown in the block diagram of FIG. The control unit 22 includes a CPU 24, and the CPU 24 has a ROM 26 and a CP for storing control programs and the like.
RAM 28 having temporary storage during control by U24 and having various flag areas required for control, I / O port 3 for CPU 24 to control input / output of internal equipment of the main body
0 and the servo motor controller 32 (hereinafter, simply referred to as “controller”) are connected. And I /
The optical sensor 18 is connected to the input port of the O port 30, and the scanner 12 is connected to the input / output terminal of the controller 32.
A motor 16 for reciprocating the motor is connected. Based on the signal received from the CPU 24, the controller 32 outputs a signal for forward rotation, reverse rotation, braking or the like to the motor 16 or controls the rotation speed thereof.

Next, the control method of the scanner 12 by the control unit 22 (FIG. 2) will be described in more detail with reference to the flow charts shown in FIGS. When the copy operation is started, the operation of the scanner 12 is started after the first paper feeding operation is completed. First, in step S1, the number of encoder pulses corresponding to the scanner movement distance in the forward movement is calculated from the paper size and the copying magnification, and the value is set in the first memory, which is a storage area in the RAM 28 (FIG. 2), Also, the initial value of the deceleration start position at the time of the backward movement corresponding to the value is set in the second memory.

Next, in step S2, the motor 16 is rotated in the normal direction to start the forward movement, and in step S3, the scanner 12 waits for the sensor to be turned off, that is, to reach the MIP. When the scanner 12 reaches the MIP, the process proceeds to step S4 and "0" is set to the first counter, which is one of the storage areas provided in the RAM 28. This first counter is always FG when the motor 16 is rotating.
It is incremented by a pulse. Step S
At 5, the process waits until the value of the first counter reaches the value set in the first memory. Here, "YES", that is, the first
If it is determined that the value of the counter is equal to the value of the first memory, it means that the forward movement for the required distance has been completed. Therefore, the process proceeds to step S6, the motor 16 is rotated in the reverse direction, and the backward movement distance is set. The first counter is cleared again to measure. Then, in step S7, it waits until the difference between the value of the first memory and the value of the first counter becomes equal to the value of the second memory. This means waiting for the scanner 12 to reach the deceleration start position before the MIP. If "YES", that is, if it is determined that the scanner 12 has reached the deceleration start position, the process proceeds to step S8 and the motor 16
Brake, clear the second counter, and
Go to step S9.

At step S9, the optical sensor 18 is turned off.
To determine if it has changed from ON to ON. In the case of "YES", the first counter is cleared to measure the distance to the MHP in step S10, and the process proceeds to step S11. In the case of "NO", the process directly proceeds to step S11.
In step S11, it is determined whether or not the scanner 12 has been decelerated below the target speed. If "YES", the process proceeds to step S12, and if "NO", the process proceeds to step S15. In step S12, it is determined whether or not the predetermined second speed has been set. If "NO", the speed is set in step S13 and the process proceeds to step S14. If "YES", the process directly proceeds to step S14 and the second speed is set. The counter starts counting the moving time of the scanner 12. In step S15, it is determined whether or not the vehicle has advanced a predetermined distance from the position at which the sensor is turned on, that is, M by the value of the first counter.
It is determined whether the HP has been reached, and if "NO", the process returns to step S9, and if "YES", the next step S9.
Proceed to 16. Here, since the first counter is not operated to detect the MHP while the step S10 is not being executed, it is not determined to be "YES".

Then, after stopping the motor 16 in step S16, the process proceeds to step S17, and it is determined whether or not the value of the second counter is within a predetermined range. This is a judgment as to whether or not the braking position was appropriate. "N
In the case of "O", the value of the second memory is corrected according to the value of the second counter in order to correct the deceleration start position in the next recovery motion in step S18, and in the case of "YES", it is not corrected. Then, it is determined whether or not the scan is a continuous scan, and if “YES”, the process returns to step S2 and “N
If it is "O", the process ends.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a control unit.

FIG. 3 is a flowchart for explaining the operation of the embodiment of FIG.

FIG. 4 is a flowchart for explaining the operation of the embodiment of FIG.

5 is a flowchart for explaining the operation of the embodiment of FIG.

[Explanation of symbols]

 10 ... Copier 12 ... Scanner 16 ... Motor 18 ... Optical sensor 20 ... Shading plate 22 ... Control unit (microcomputer system)

Claims (1)

Claim: What is claimed is: 1. A scanner which reciprocates for exposing and scanning an original, a means for detecting a reference position of the scanner, and a scanner which is moved back at a first speed when the scanner is moved back, and is moved at a predetermined position. In a copying machine provided with a first control unit that switches to a second speed that is slower than the first speed and stops the scanner at the reference position, a unit that detects the time when the scanner moves at the second speed when the scanner returns. A copying machine, comprising: second control means for changing the predetermined position for switching from the first speed to the second speed at the time of the next recovery movement according to the detected time.