JP2002277971A - Stepping motor driving control method and program for making computer implement the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepping motor driving control method which can efficiently prevent step out. SOLUTION: By a stepping motor driving control method for a document reader equipped with a stepping motor 8 which moves a scanning optical system for reading a document on a document platen in a vertical scanning direction, a driving control plate 21 which drives the stepping motor 8 under slow-up control, a scanner control plate 20 which gives a control signal to the driving control plate 21, and a speed detector 22 which detects the speed variation of the scanning optical system, the signal of the speed detecting device in a certain period from the start of the return actuation of the scanning optical system is compared with a prescribed speed reference level value and the speed pattern of forward falling is varied according to the comparison value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control method for a stepping motor used in a copying machine, a facsimile, and a single scanner, and a program for causing a computer to execute the method.

[0002]

2. Description of the Related Art In a conventional stepping motor control method, for example, in the invention described in Japanese Patent Application Laid-Open No. 8-204908, a plurality of startup patterns are stored as a countermeasure for forward step-out, and a plurality of patterns are stored depending on the result of position detection means. There has been a configuration in which the image reading process can be continued even if the user steps out of synchronization.

[0003]

However, in the above-mentioned prior art, there is a problem that the speed pattern cannot be changed without step-out. Further, when the speed pattern is changed, the rising and falling patterns are changed, so that there is a problem in that the reading process step time is increased and the cpm is reduced.

It is an object of the present invention to provide a stepping motor drive control method capable of efficiently preventing step-out and a program for causing a computer to execute the method.

[0005]

According to a first aspect of the present invention, there is provided a stepping motor drive control method for controlling a scanning optical system for reading a document on a document table in a sub-scanning direction. , A stepping motor drive control plate for driving the stepping motor by slow-up control, a scanner control plate for providing a control signal to the stepping motor drive control plate, and detecting a speed fluctuation of the scanning optical system. A speed detection device, and a stepping motor drive control method for a document reading device, comprising: a signal of the speed detection device within a fixed period from the start of return start of the scanning optical system; and a speed reference level value defined in advance. Are compared, and the forward fall speed pattern is changed according to the comparison value.

According to a second aspect of the present invention, there is provided a stepping motor drive control method according to the first aspect, wherein a plurality of forward falling patterns are stored.

According to a third aspect of the present invention, there is provided a stepping motor drive control method according to the first aspect, wherein the forward fall speed pattern is changed in accordance with the specified zooming speed of the scanning optical system. It is characterized by.

A program according to a fourth aspect of the present invention allows a computer to execute the method according to any one of the first to third aspects.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a stepping motor control method according to the present invention and a program for causing a computer to execute the method will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram showing a configuration of a drive system of a reading device in a stepping motor control method according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a schematic configuration of the reading device. It is. 1 and 2, the scanner control board 20 uses the data transmitted from a higher-level control device (not shown) to change the magnification information and the speed damping at the start of the return detected by the speed detection device 22. The voltage value is compared with a value previously stored in a memory in the control board as a speed reference level.

Then, based on the comparison result, the scanner control board 20 selects one of a plurality of forward fall patterns in which the fall is stored, forms a drive clock signal based on the data, and generates a drive clock signal. The drive clock signal is output to the drive control board 21.

In FIG. 2, reference numeral 13 denotes a contact glass (original table), 14 denotes an exposure lamp, 15 denotes a first mirror, 16 denotes a second mirror, 17 denotes a third mirror, 18 is an imaging lens, 19 is CC
D is a scanner control board for controlling image processing and a drive control board 21, and 21 is a drive control board for driving and controlling a stepping motor.

Next, an outline of the driving system will be described with reference to FIG. First, power is transmitted to the first carriage 1 and the second carriage 2 via wires 3 stretched over two objects. The wire 3 is driven by a wire pulley 5 wound on a drive shaft 4 and integrated with the shaft. The wire pulley 5 is integrated with a shaft of a stepping motor 8 via a timing belt pulley 9 and a timing belt 7 which are coaxial. Driven by the driven timing belt pulley 10. A speed detecting device 22 is attached to the drive shaft 4.

When the power switch is turned on, the stepping motor 8 starts driving for homing. Accordingly, the first carriage 1 and the second carriage 2 move forward. Then, when the first carriage 1 and the second carriage 2 move by a fixed distance, the reverse rotation (return) starts this time. Home position sensor 12
When the detecting unit 11 detects the detecting unit 11 below the first carriage 1, the first carriage 1 and the second carriage 2 move by a predetermined pulse, stop, and stand by at this position.

FIG. 3 is a block diagram for explaining the contents of the stepping motor drive control in the stepping motor drive control method according to the embodiment of the present invention. In the block diagram of FIG.
Are driven by the drive control plate 21. Drive control plate 21
A motor drive clock, a forward / reverse rotation signal, a division number switching signal for micro-step driving, and a driving current switching (motor current switching) signal from a scanner control board 20 equipped with an upper CPU (not shown). The drive current flowing through each phase of the stepping motor 8 is controlled by these signals.

The speed of the stepping motor 8 is determined by the frequency of the motor driving clock. As the clock frequency of the motor drive clock increases, the rotation speed increases. Conversely, when the clock frequency decreases, the rotation speed decreases. Therefore, various slow-ups can be realized by controlling the driving clock frequency.

The speed detector 22 converts the rotation speed into a voltage and sends the voltage to the scanner control board 20. The scanner control board 20 receives a speed fluctuation (hereinafter referred to as speed damping) as a voltage value sent from the speed detecting device 22. The scanner control board 20 uses the data transmitted from a higher-level control device (not shown) to transmit the magnification information, the magnification value, the voltage value of the speed damping detected by the speed detection device 22 at the start of the return, and the speed reference information. The level is compared with a value previously stored in a memory in the control board.

Then, based on the result, the scanner control board 20 selects one of a plurality of forward fall patterns in which the fall is stored, forms a drive clock signal based on the data, and generates the drive clock signal. Is output to the drive control plate 21.

A document is placed on the contact glass 13 and
When the start key is pressed, a drive clock for a forward rising is output from the scanner control board 20 to the drive control board 21 at a predetermined timing, and the stepping motor 8 starts driving. The basics of the drive control are based on the speed pattern shown in FIG.

The first carriage 1 and the second carriage 2 start running in the forward direction by the driving of the stepping motor 8, and irradiate a document (not shown) placed on the contact glass 13 with the exposure lamp 14. The reflected light is transmitted to the first mirror 15, the second mirror 16, and the third mirror 17
An image is formed on the CCD 19 by the image forming lens 18 through the interface, and the original is read. The read image data is transferred to the scanner control board 20 and performs image processing.

When the reading of the original is completed, the process proceeds to the return step. The stepping motor 8 starts reverse rotation.
The first carriage 1 is moved at a high speed, and the second carriage 2 is moved.
Makes a fast return at half the speed. And the first
When the home position sensor 12 detects the detection unit 11 provided on the carriage 1, it moves by a certain pulse and the stepping motor 8 stops.

Next, more specific contents of the drive control of the stepping motor will be described. The stepping motor 8 is controlled according to the speed pattern shown in FIG. For the acceleration pattern table, prepare one acceleration pattern at the time of 25% reduction, which is the fastest in order to minimize the memory,
Other zooming uses a part of the acceleration pattern of 25% reduction as shown in FIG.

Further, since the frictional load acts as a brake in the deceleration pattern, it can be lowered more rapidly than in the rising acceleration pattern. However, since it takes too much time for one deceleration pattern at the time of 25% reduction,
At the time of reduction, for example, if it falls in 40 ms, 50
The% reduction falls in 20 ms, but since the maximum speed is half of 25%, the motor torque can rise and fall in 10 ms. Then, instead of providing a deceleration pattern in accordance with all the magnifications, the magnification is divided into blocks, and about 3 to 4 deceleration patterns are stored.

FIG. 5 shows the overall speed fluctuation when the reduction ratio is 25% and the damping at the time of return when the present invention is not operated. Step out depending on the magnitude of the damping immediately after the start of the return. Causes of this damping are as follows, for example.

(1) It is generated under the influence of damping of the falling edge at the time of forward. (2) Damping occurs due to a sudden acceleration pattern at the rise of the return.

With respect to the above (2), it is possible to prevent the occurrence by causing the acceleration pattern at the rise of the return to lie down. However, in the case of the above (1), it is difficult to prevent the occurrence unless the forward deceleration pattern is changed to eliminate the damping. Therefore, the speed detecting device 22
The rotation speed is converted into a voltage, and the voltage (value) is sent to the scanner control board 20.

The scanner control board 20 reads the maximum and minimum of the speed fluctuation voltage value within a predetermined time from the start of the return from the sent speed fluctuation voltage value. If the width is smaller than a predetermined speed reference level voltage value, it is determined that the damping is not yet performed until the step-out occurs, and is sent to the scanner control board 20. The forward deceleration pattern is not changed depending on the result. If it is larger than the speed reference level voltage value, it is determined that step-out may occur, and the forward deceleration file is changed.

FIG. 6 shows a speed fluctuation waveform when the forward deceleration pattern is changed when it is determined that a step-out may occur if the speed is larger than the speed reference level voltage value, as described above. This is a velocity waveform when a deceleration pattern in which the deceleration time T2 is twice as long as T1 is selected from a plurality of stored deceleration patterns. Damping on the return side does not occur and there is no risk of step-out.

In the stepping motor drive control method according to the embodiment of the present invention, a plurality of forward falling patterns are stored. Damping is caused by a change in friction load between the first carriage 1 and the second carriage 2, a change in friction between the wires 3, a change in friction between the wires 3 and the wire pulley 5, and a change in friction load due to the extension of the timing belt 7, including aging. Since it changes, damping at the time of return can be suppressed by coping with a plurality of stored deceleration patterns, and step-out can be prevented.

In the stepping motor drive control method according to the embodiment of the present invention, it takes too much time for one pattern of deceleration at the time of 25% reduction. Then, the 50% reduction falls in 20 ms, but since the maximum speed is half that of 25%, the motor torque increases and it can fall in 10 ms.

Instead of providing a deceleration pattern in accordance with all the scaling factors, storing the deceleration patterns of about 3 to 4 by dividing the scaling factors into blocks so as to minimize the overall time. , Cpm can be prevented without lowering cpm.

The stepping motor drive control method according to the present embodiment may be a computer-readable program prepared in advance, and may be executed by executing the program on a computer such as a microcomputer or a personal computer. Is achieved. This program includes HD (hard disk), FD (floppy (registered trademark) disk), CD
-The program is recorded on a computer-readable recording medium such as a ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. Also,
This program may be a transmission medium that can be distributed via a network such as the Internet.

[0033]

As described above, according to the present invention, the signal of the speed detecting device within a fixed period from the start of the return start of the scanning optical system is compared with a predetermined speed reference level value, and the forward value is calculated based on the comparison value. And a program for causing a computer to execute the stepping motor drive control method capable of preventing step-out by changing the falling speed pattern of the stepping motor.

Further, according to the present invention, damping changes due to frictional load fluctuations and the like including temporal changes. Therefore, by selecting a plurality of deceleration patterns, damping at the time of return can be suppressed. Toning can be prevented. Further, according to the present invention, a plurality of deceleration patterns are selected based on the magnification (rather than providing the deceleration patterns in accordance with all the magnifications, the demagnification is divided into blocks and about three to four deceleration patterns are stored). By doing so, step-out can be prevented without lowering the cpm in order to minimize the overall time.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a drive system of a reading device in a stepping motor control method according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a reading device in the stepping motor control method according to the embodiment of the present invention;

FIG. 3 is a block diagram illustrating a configuration of a drive control system of the reading device in the stepping motor control method according to the embodiment of the present invention;

FIG. 4 is an explanatory diagram showing a speed pattern.

FIG. 5 is an explanatory diagram showing overall speed fluctuation when the reduction ratio is 25% and damping at the time of return when the present invention is not operated.

FIG. 6 is an explanatory diagram showing a speed fluctuation waveform when a forward deceleration pattern is changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st carriage 2 2nd carriage 3 Wire 4 Drive shaft 5 Wire pulley 7 Timing belt 8 Stepping motor 9 Timing belt pulley 13 Contact glass (document table) 14 Exposure lamp 15 First mirror 16 Second mirror 17 Third mirror 18 Image lens 19 CCD 20 Scanner control plate 21 Drive control plate 22 Speed detector

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04N 1/10 H04N 1/10 1/107 F term (Reference) 2H107 AB22 DA34 5B047 AA01 BA02 BB02 BC05 BC09 BC11 CA08 CB07 CB17 5C072 AA01 BA13 CA02 DA02 DA04 EA05 MB03 MB08 UA13 XA01 5H580 AA04 AA07 BB06 FA14 FA24 FB01 FB03 FC09 GG04 HH08

Claims (4)

[Claims] A stepping motor for moving a scanning optical system for reading a document on a platen in a sub-scanning direction;
A stepping motor drive control plate that drives the stepping motor by performing slow-up control, a scanner control plate that provides a control signal to the stepping motor drive control plate, and a speed detection device that detects a speed variation of a scanning optical system;
A method for controlling the driving of a stepping motor of a document reading apparatus, comprising: comparing a signal of the speed detection device within a predetermined period from the start of return activation of the scanning optical system with a speed reference level value defined in advance; A stepping motor drive control method characterized by changing a forward falling speed pattern according to a comparison value. 2. The drive control method for a stepping motor according to claim 1, wherein a plurality of forward falling patterns are stored. 3. The stepping motor drive control method according to claim 1, wherein the forward fall speed pattern is changed in accordance with a specified zooming speed of the scanning optical system. 4. A program for causing a computer to execute the method according to claim 1.