JPH03178598A - Motor control method for picture input device - Google Patents

Abstract

PURPOSE:To perform high-speed/low-speed reading of a video signal by decreasing a driving current, raising torque, reducing noise and making a frequency equal at the time of a high speed through switching a motor to be driven in the subscan direction to a monophase excitation or (1-1)-1 phase excitation according to the reading rate while changing the taking-in method of the video signal. CONSTITUTION:At the time of a high resolution reading in the subscan direction of a picture input device 1, a master controller 2 generates a control signal for driving a motor 5 by (1-1)-1 phase excitation. At the time of a high-speed reading, on the other hand, the controller generates a control signal for driving the motor 5 by a monophase excitation without changing a fundamental frequency while controlling a resolution in the main scanning direction in the same way as that taken in the subscan direction. Then, the motor 5 is driven by the control signal corresponding to a read rate so that a manuscript is read with high resolution or at high speed. Thus, a driving current is decreased, torque is raised, noise is reduced and frequency is made equal at the time of a high speed to enable the high speed/low-speed reading of a video signal.

Description

[Detailed Description of the Invention] [Summary] Regarding a motor control method for switching the speed of a motor for driving in the sub-scanning direction of an image input device, the motor for driving in the sub-scanning direction is subjected to l-phase excitation or (I-phase excitation) depending on the reading speed. -1)
-The purpose is to switch to 1-phase excitation, change the way the video signal is captured, reduce the drive current at high speed, use torque amplifier, reduce noise, and read the video signal at high or low speed by keeping the frequency the same. , a motor that can be switched to either l-phase excitation or (I-1)-1 phase excitation is provided, and the motor is driven with (I-1)-1 phase excitation during high resolution reading in the sub-scanning direction of the image input device. and without changing the fundamental frequency during high-speed reading.
The motor is driven by l-phase excitation, and the resolution in the main scanning direction is made to match the resolution in the sub-scanning direction.

[Industrial application field]

The present invention relates to a motor control method for switching the speed of a motor for driving an image input device in the sub-scanning direction.

[Image input devices (image scanners, etc.) are becoming increasingly high-resolution,
There is a demand for more detailed input, and there is also a demand for high-speed reading and an overview of the situation even if the resolution is reduced. Conventionally, in order to satisfy both of these requirements, when the basic reading frequency of the motor that drives in the sub-scanning direction was increased, the drive voltage and 1st current were increased to compensate for the decrease in torque in the high-speed range, or the chitsunopa There was a problem in that it was a heavy burden to introduce the two methods. In addition, if the current is set to keep the noise low at the basic reading frequency, the torque will not move during high-speed reading due to insufficient torque.On the other hand, if the current is set during high-speed reading J'J, the torque will be excessive at the basic reading frequency and the noise will increase. There were also problems such as storage.

The present invention switches the motor for driving in the sub-scanning direction to l-phase excitation or (I-1)-1 phase wJ magnetization depending on the reading speed, changes the way of capturing video signals, and changes the drive current at high speed. The purpose is to increase torque, reduce noise, and make the frequency the same for high-speed/low-speed reading of video signals.

(Means to solve Ltd!) A means for solving the problem with reference to FIG. 1 will be explained.

In FIG. 1, the main control unit 2 controls the motor 5 by (T-1)-1 during high-resolution reading in the sub-scanning direction of the image input device l.
A control signal is generated to drive the motor 5 by phase excitation, while the motor 5 is
! It generates a control signal for driving with J magnetism and controls the resolution in the main scanning direction to be the same as that in the sub-scanning direction.

The motor 5 is a motor that can be switched to either l-phase excitation or (I-1)-1 phase excitation.

[Effect]

In the present invention, as shown in FIG. 1, the main controller 2 controls the motor 5 (
I-1) - Generates a control signal to drive with 1-phase excitation, while generating a control signal to drive motor 5 with I-phase rfIJ magnetism without changing the fundamental frequency during high-speed reading, and generates a control signal to drive the motor 5 with I-phase rfIJ magnetism. Control the resolution to be the same as in the sub-scanning direction,
The motor 5 is controlled by the control signal corresponding to the reading speed.
is driven to read documents with high resolution or at high speed.

Therefore, by switching the motor 5 for driving in the sub-scanning direction to l-phase excitation or ([-1)-1 phase excitation according to the reading speed and switching the video signal capture method, the drive current at high speeds can be adjusted. It becomes possible to perform high-speed/low-speed reading of video signals with reduced torque, torque amplifier, noise reduction, and the same frequency.

〔Example〕

Next, the configuration and operation of the L embodiment of the present invention will be explained in detail one by one using FIGS. 1 to 6.

In the figure, an image reading device l is a scanner or the like that reads an image of a document.

The main control section 2 is composed of a video capture control signal generation section 2-1, etc., and generates a control signal to drive the motor 5 with (r-1) - On the other hand, it generates a control signal for driving the motor 5 with one phase IBM without changing the fundamental frequency during high-speed reading, and controls the resolution in the main scanning direction to be the same as that in the sub-scanning direction. be.

The video capture control signal generation unit 2-1 generates a control signal to be captured into a video signal from a signal read from a document.

The stevening motor controller 3 has a basic frequency (basic clock), [phase wIM! signal (or (I-1>
A signal that drives the motor (stepping motor) 5 based on the -1 phase excitation signal (Figure 2 (a) or Figure 3 (
b) Generates a drive waveform (see drive waveform) and controls the motor 5.

The stepping motor driver 4 amplifies the inputted drive signal to drive the motor 5. The motor (stepping motor) 5 is a motor for driving in the sub-scanning direction.

The CCD sensor 6 is a sensor that reads a document in the main scanning direction.

Video driver/controller 7 includes CCD-sensor 6
It controls the number 0 read from the manuscript and amplifies it.

The buffer memory 8 is a memory that temporarily stores Nobukiyo read from the original.

The host 9 instructs the image reading device 1 to read a Wi document, receives read image signals, and stores them in the memory 10.

I-phase excitation will be explained using FIG. 2.

FIG. 2(a) shows the ON10 FF shape of the drive current in each phase of two-phase excitation, which is l-phase excitation. Here, ■ to ■ indicate the stable stopping positions shown in FIG. 2 (b), respectively.

Figure 2 (b) shows the arrangement and stable positions (■ to ■) of each phase during two-phase excitation, which is l-phase excitation. In the case of this two-phase magnetization, the stable positions are ■, ■, ■,
Compared to the 1>-1 phase wJ magnet, it is possible to drive at twice the speed with the same fundamental frequency. In addition, since the drive current is always applied to the two phases at each stable position and the average drive current is supplied as a whole, when the maximum supply current is constant (that is, the final stage transistor that supplies the current (When the maximum current value is constant), it is possible to always flow a large current on average and obtain a large torque.

(I-1)-IIg excitation will be explained using FIG.

Figure 3 (a) shows the drive current of 0N10 F F in each phase during 1-2 phase excitation, which is (I-1)-[phase excitation.
Indicates the status of Here, ■ to ■ indicate the stable stopping positions shown in FIG. 3(b), respectively.

Figure 3 (b) shows (I-1)-1 phase yF11 magnetic 1
- Indicates the arrangement and stable position (■ or ■) of each phase during 2-phase excitation. In the case of this 1-2 phase excitation, the stable position is: ■, ■, ■, ■, ■, ■, ■ ,■ position,
It has a step angle of 45°, and compared to the l-phase excitation described above,
172 times slower driving is possible with the same fundamental frequency. Further, drive current is caused to flow through one or two phases at each stable position.

As described above, it is possible to perform high-speed drive, high torque, and noise reduction during phase excitation in FIG. 2, and low-speed drive during phase excitation in FIG. 3 (I-1)-1.

The details will be explained below.

+1+ Perform sub-scanning using a two-phase pulse motor with an image scanner.

Basic reading (low-speed drive): 1-2 phase a magnetic (see Figure 3) High-speed reading (high-speed drive): 2-phase excitation (see Figure 2) The imaging system includes a reflective mirror, lens, and CCD sensor 6. The two-phase pulse motor reads the document while moving in the sub-scanning direction.

The magnification of the imaging system is set so that the reading density is 400 DPI.

The transmission gear is configured with a reduction ratio such that when the two-phase pulse motor moves one step with 1-2 phase excitation, the carrier moves in the sub-scanning direction by 1 dont of 400DP1 -25.4mm/400=0°0625mm. There is.

(2) During high-resolution reading (basic reading): The two-phase pulse motor is driven at fpps with 1-2 phase excitation. At this time, 1/f=TscAN (Tscas: 1 rask scanning time of the video signal), and the video signal for each scan is captured as an image signal (video signal).

(3) When reading at low resolution (when reading at high speed): The two-phase pulse motor is driven at fpps with two-phase excitation. At this time, 1/f = T 5cAn, but the carrier moves at twice the speed of 1-2 phase excitation, and in l steps 0.0625X2 = 0. Since it moves by 125 mm, the resolution in the sub-scanning direction is 200 DPI. In order to match this resolution, in the main scanning direction (direction of the CCD sensor 6), two pixels are averaged and taken as one pixel, or every other pixel is taken in to make 200DPI, and 2000PI
Assume that the data is two-dimensional. In addition, the input time to capture one image is 172 at 400DPI (at high resolution).
This enables high-speed input. In addition, with 1-2 phase excitation, 2
Rather than operating a pulse motor at twice the frequency, operating it at the same frequency with two-phase excitation provides higher torque as mentioned above, reduces the maximum current to about half, and allows for more compact equipment manufacturing. .

With reference to FIG. 4, an explanation will be given of the operation when the reading area of the original is driven at high speed and the reading area is driven at low speed.

In Figure 4 (b), ■ is in front of the reading position (I
<L). This is because the distance j11 scanned from the leading edge of the document in the sub-scanning direction in FIG. 4(A) is smaller than the position of the reading area (I<L> or not. Y)
In the case of ES, fast forwarding is performed by I-phase excitation drive with @. On the other hand, in the case of No, high resolution reading is performed by <1-4)-1 phase excitation drive with 0.

With the above control, the second
Figure ■ Skip by phase excitation drive, Figure 3 (I
-1>-1 phase rib magnetic drive for high resolution reading.

The operation of reading the high-resolution reading area and the low-resolution reading area will be explained using FIG. 5.

In FIG. 5(b), ■ is used to determine whether or not the reading position is reached. This is done by scanning from the leading edge of the document in the sub-scanning direction as shown in FIG. If YES, do ■; if NO,
Fast forward to the reading position.

@ determines whether or not it is high resolution reading. This is the fifth
In the figure (A), it is determined whether or not the position of the high resolution reading area has been reached. If YES, high-resolution reading is performed in [phase], while if NO, low-resolution reading is performed in [phase].

(2) Reads with high resolution using (I-1)-1 phase excitation drive.

In [phase], high-speed reading is performed at low resolution by phase excitation drive, and as described above, thinning or averaging is performed in the main scanning direction to match the resolution in the sub-scanning direction.

By using the above control fIG, high resolution reading is performed in the high resolution reading area of the document using the ([-1)-1 phase excitation drive in Figure 3, while low resolution reading is performed in the low resolution reading area using the I phase excitation drive in Figure 2. Reads at high resolution and at high speed.

The operation at the time of reading and returning the high resolution reading area will be explained using FIG.

In Figure 6 (b), ■ is (r-1)-1 phase excitation 16
1 drive. This means that the document is scanned from the leading edge of the document in the sub-scanning direction as shown in FIG. 6 (A) to the end of the document as shown in FIG.
1) Read with high resolution using -1 phase dynamic magnetism.

(2) returns by ] phase excitation drive. this is,[
After reading is completed to the end of the document in FIG. 6(a), the device returns at high speed (returns to the position where reading of the document starts) using the I-phase excitation drive in FIG.

More than tJl? ml performs high-resolution reading from the beginning to the end of the document, and returns to the leading edge of the document at high speed when returning.

〔Effect of the invention〕

As described above, according to the present invention, the motor 51 for driving in the sub-scanning direction is switched to I-phase excitation or (I-1)-1 phase excitation according to the reading speed, and the method of capturing video signals is also switched. Since this configuration is adopted, it is possible to reduce the drive current during high-speed driving, use a torque amplifier, reduce noise, and make high-speed/low-speed reading possible by keeping the frequency of the video signal the same.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of one embodiment of the present invention, Fig. 2 is a one-phase l1l diagram.
FIG. 3 is an explanatory diagram of (I-1)-1 phase excitation, and FIGS. 4, 5, and 6 are detailed explanatory diagrams of the present invention. In the figure, l is an image reading device, 2 is a main control unit, 21 is a video capture control signal generator, 3 is a stepping motor controller, 5 is a motor (stepping motor), and 6 is a CC
Represents D sensor.

Claims (1)

[Claims] In a motor control method for switching the speed of a motor for driving in the sub-scanning direction of an image input device, I-phase excitation and (I
-1) - Motor that can be switched to either I-phase excitation (5
), the motor (5) is driven with (I-1)-I phase excitation during high-resolution reading in the sub-scanning direction of the image input device, and the motor (5) is driven with (I-1)-I phase excitation during high-speed reading without changing the fundamental frequency. 1. A method for controlling a motor for an image input device, characterized in that the motor is driven by I-phase excitation, and the resolution in the main scanning direction is controlled to match the resolution in the sub-scanning direction.