JPH09116703A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent low vibration of an optical body by controlling a drive current of a motor driving the optical body so as to drive the motor with a current corresponding to a load torque even when the load torque of the optical body thereby driving the optical body with a minimum drive torque corresponding to the load torque. SOLUTION: Whether or not an optical body 4 is driven at a prescribed location within a prescribed time is checked based on a detection result of an optical sensor 8 at rising of the image reader 1. Based on the check result, a drive current of a stepping motor 10 to drive the optical body 4 is adjusted to allow the stepping motor 10 to produce a torque a little larger than a load torque of the optical body 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading an image of an original by driving an image scanning unit by a motor driven by a constant current, such as a digital copying machine.

[0002]

2. Description of the Related Art As a device for driving a movable member or an image scanning unit by a motor to convey the member or read an image of an original, a "copying device" disclosed in Japanese Patent Laid-Open No. 1-140898 has been disclosed. Also, "a control device for a movable member" disclosed in JP-A-60-512 is known. In this case, in the "copying device" disclosed in Japanese Unexamined Patent Publication No. 1-140898, the frequency calculating unit calculates the frequency of step-out that occurs in the stepping motor that drives the scanning optical system, and After the frequency calculated by the frequency calculation means is stored, the stepping motor is driven by the drive control means based on the past frequency stored in the frequency storage means and the current frequency calculated by the frequency calculation means. By controlling the driving of the stepping motor, the voltage applied to the stepping motor is appropriately switched according to the step-out occurrence frequency of the stepping motor, and the scanning optical system is driven reliably and smoothly. Further, in the "movable member control device" disclosed in Japanese Patent Laid-Open No. 60-512, a drive pulse is generated by a pulse generating means, and a drive pulse output from the pulse generating means by a pulse motor drive circuit. By adding a predetermined number of drive pulses to the pulse motor by detecting the predetermined position of the movable member controlled by the pulse motor by the position detection means while adding the pulse motor to the pulse motor, When the predetermined position has not been reached, it is determined that some abnormality has occurred in the drive system of the movable member.

[0003]

By the way, in such an image reading apparatus, each excitation coil of the stepping motor is turned on / off in accordance with a phase excitation pattern according to a rotation direction, a rotation step angle and the like. Since a stepping motor is rotated by supplying a driving current (driving pulse) having a magnitude, when driving an optical traveling body, optical traveling due to torque fluctuation when the driving pulse for driving the stepping motor changes. In order to reduce body vibration, it is necessary to bring the torque generated by the stepping motor close to the minimum torque required to drive the optical traveling body as much as possible. However, unless a certain margin is provided for the required torque, the stepping motor may be out of step if the minimum torque required to drive the drive system increases due to changes over time. . For this reason, it is necessary to control the stepping motor with a driving force that is equal to or greater than the required minimum torque, and there is a problem that vibration of a low frequency occurs in the optical traveling body due to the excessive torque. . With respect to this point, no means for solving the problems is shown in the above-mentioned copying apparatus and control apparatus for the movable member.

In view of the above circumstances, the present invention according to claim 1 detects whether or not the optical traveling body has been driven to a predetermined place within a predetermined time when the image reading apparatus is started up, and based on this detection. By controlling the drive current of the motor that drives the optical traveling body, even if the load torque of the optical traveling body changes due to changes over time, the motor is driven with a drive current corresponding to this. Accordingly, it is an object of the present invention to provide an image reading apparatus capable of traveling an optical traveling body with a minimum drive torque corresponding to the load torque and preventing low vibration of the optical traveling body.

According to a second aspect of the present invention, the reference image pattern is stored in the memory provided in the apparatus, the reference image pattern is printed on the sheet by the image forming unit, and then the optical traveling body is run. When reading the image of the paper on which the reference image pattern is printed, while changing the driving current of the motor stepwise, the image pattern obtained by this reading operation is compared with the reference image pattern,
An object of the present invention is to provide an image reading device capable of preventing the vibration of an optical traveling body by driving the motor with a drive current that minimizes the difference between these patterns and also minimizes the torque generated by the motor. I am trying.

According to a third aspect of the present invention, a vibration measuring element is provided in the optical traveling body, and when the image reading device is started up,
When the optical traveling body is being driven, the vibration of the optical traveling body is measured by the vibration measuring element while changing the drive current of the motor stepwise, and the vibration of the optical traveling body is measured based on the measurement result. It is an object of the present invention to provide an image reading device capable of preventing the vibration of the optical traveling body by driving the motor with a drive current that minimizes the torque and the torque generated by the motor.

[0007]

In order to achieve the above object, the present invention according to claim 1 is directed to an image of an original while an optical traveling body is caused to travel using a motor controlled by constant current control as a power source. In the image reading device that reads the, while operating the motor while switching the current value of the drive current supplied to the motor stepwise, while driving the optical traveling body with the driving force obtained by the motor,
It is characterized in that the running state of the optical traveling body is checked, and the current value of the drive current capable of generating the minimum torque required to drive the optical traveling body is determined based on the check result.

Further, according to a second aspect of the present invention, a reference image pattern stored in advance is stored in an image reading apparatus which reads an image of an original while the optical traveling body is caused to travel using a motor controlled by constant current control as a power source. The current value of the drive current supplied to the motor is supplied to the image forming unit, the reference image paper on which the reference image pattern is printed is discharged from the image forming unit, and the motor is supplied with the reference image paper set. While stepwise switching, while operating the motor, with the driving force obtained by this motor,
While driving the optical traveling member, the image data of the reference image paper obtained by traveling the optical traveling member and the reference image pattern are compared to generate image error data indicating these errors, Based on each of these image error data, the current value of the drive current that can minimize the image data of the reference image paper and the reference image pattern is obtained, and this current value is the current of the drive current supplied to the motor. It is characterized by setting it as a value.

According to another aspect of the present invention, in an image reading device that reads an image of an original while an optical traveling body is driven by using a motor controlled by constant current control as a power source, a current of a driving current supplied to the motor. The vibration detection signal output from the vibration measuring element provided on the optical traveling body while operating the motor while changing the value stepwise and driving the optical traveling body with the driving force obtained by the motor. Is checked, and the current value of the drive current capable of driving the optical traveling body with the least vibration is determined based on the check result.

In the above structure, according to the first aspect of the invention, in the image reading apparatus for reading the image of the original while the optical traveling body is driven by using the motor controlled by the constant current control as the power source, the drive is supplied to the motor. While switching the current value of the current stepwise, the motor is operated, and the driving force obtained by the motor is used to drive the optical traveling body to check the traveling state of the optical traveling body. Based on, by determining the current value of the drive current that can generate the minimum torque required to drive the optical traveling body, due to changes over time,
Even if the load torque of the optical traveling body changes, the motor is driven by the drive current corresponding to the load torque, and thereby the optical traveling body is caused to travel with the minimum drive torque corresponding to the load torque. To prevent low vibration.

Further, according to a second aspect of the present invention, a reference image pattern stored in advance is read by an image reading device which reads an image of a document while the optical traveling body is driven by using a motor controlled by constant current control as a power source. The current value of the drive current supplied to the motor is supplied to the image forming unit, the reference image paper on which the reference image pattern is printed is discharged from the image forming unit, and the motor is supplied with the reference image paper set. While stepwise switching, while operating the motor, with the driving force obtained by this motor,
While driving the optical traveling member, the image data of the reference image paper obtained by traveling the optical traveling member and the reference image pattern are compared to generate image error data indicating these errors, Based on each of these image error data, the current value of the drive current that can minimize the image data of the reference image paper and the reference image pattern is obtained, and this current value is the current of the drive current supplied to the motor. By setting the value to the value, the image on the reference image paper can be correctly read, and the motor is driven by the drive current that minimizes the torque generated by the motor to prevent the vibration of the optical traveling body.

Further, according to a third aspect of the present invention, in an image reading device for reading an image of an original while an optical traveling body is driven by using a motor controlled by constant current control as a power source, a current of a driving current supplied to the motor. The vibration detection signal output from the vibration measuring element provided on the optical traveling body while operating the motor while changing the value stepwise and driving the optical traveling body with the driving force obtained by the motor. The value of the drive current that can be driven with the least vibration of the optical traveling body is determined based on the check result, thereby minimizing the vibration of the optical traveling body, and The motor is driven with a drive current that minimizes the generated torque to prevent vibration of the optical traveling body.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a sectional view showing a first embodiment of the image reading apparatus according to the present invention. An image reading apparatus 1 shown in this figure has a casing 2 formed in a rectangular shape, a contact glass 3 fitted in an opening formed in an upper portion of the casing 2, and arranged inside the casing 2. A guide rail (not shown) is provided so as to be movable in the sub-scanning direction, and the optical traveling body 4 is disposed on the optical traveling body 4 and is mounted on the contact glass 3. A light source 6 for illuminating the original 5 and a reflecting mirror 7 arranged on the optical traveling member 4 for reflecting light (optical image) from the original 5 and making it incident on a light receiving element (not shown).
And an optical sensor 8 which is disposed in the casing 2 and detects the optical traveling body 4 at the origin (initial position) of document scanning and outputs an ON signal, and the inside of the casing 2. And a control board 9 for controlling the operation of each part of the apparatus based on a preset program, and a drive current value output from the control board 9 arranged in the housing 2. A stepping motor 10 for driving the optical traveling body 4 with a corresponding torque is provided. When the image reading apparatus 1 is powered on, the stepping motor 1
While sequentially switching the current value (driving current value) of the driving current with respect to 0, the minimum driving current value with which the optical traveling body 4 can be correctly traveled is obtained and stored.
After that, the stepping motor 10 is driven by a drive current having this drive current value to read the image of the document 5 set on the contact glass 3 while the optical traveling body 4 is traveling to generate image data.

Next, the control board 9 will be described in detail with reference to the block diagram shown in FIG. As shown in this figure, the control board 9 includes the stepping motor 1
A stepping motor control unit 11 for controlling the driving of 0,
A central processing unit 12 that controls the operations of the stepping motor control unit 11 and the like is provided, and when the image reading apparatus 1 is powered on,
A drive current having a preset current value (initial current value) is supplied to start the traveling of the optical traveling body 4, and
Within a predetermined time from this time, it is checked whether the optical traveling body 4 is separated from the initial position, and when it is not separated, the current value of the drive current applied to the stepping motor 10 is sequentially increased, A drive current value with which the optical traveling body 4 can be traveled is obtained and stored, and thereafter, the stepping motor 10 is driven by a drive current having this drive current value to drive the optical traveling body 4 while traveling. , The image of the document 5 set on the contact glass 3 is read to generate image data. In this case, the central processing unit 12 has a timer, and a CPU circuit 13 for performing various control processing, data processing, etc. based on a preset program, processing for measuring time using this timer, The CPU circuit 13 includes a RAM circuit 14 used as a work area and a data storage area for various processes executed by the CPU circuit 13, and a process of measuring time based on a preset program, the stepping motor control unit. 11 is performed to perform a designated operation, a process of switching the current value of the drive current to the stepping motor 10 based on the output of the optical sensor 8 is performed.

Further, the stepping motor controller 11
Is a D / A converter circuit 15 for D / A converting 4-bit drive current value setting data output from the CPU circuit 13 to generate a drive current value setting signal; / A converter circuit 15 for receiving a drive current value setting signal, an operational amplifier 16, a resistor 17 for pulling down the non-inverting input terminal of the operational amplifier 16, and a fed back current value detection signal for inverting the operational amplifier 16. The D / A is composed of an input resistor 18 that leads to an input terminal and a feedback resistor 19 that connects the inverting input terminal and the output terminal of the operational amplifier 16.
A deviation detection circuit 20 is provided which compares the drive current value setting signal output from the converter circuit 15 with the current value detection signal and generates a deviation signal corresponding to the difference between them.

Further, the stepping motor controller 1
1 is for driving each exciting coil 21 of the stepping motor 10 with a constant current based on the phase excitation pattern for each phase output from the CPU circuit 13 and the deviation signal output from the deviation detecting circuit 20. A drive circuit 22 for each phase that generates a necessary drive signal and a drive current for each exciting coil 21 of the stepping motor 10 by conducting at a conduction rate according to the value of the drive signal output from each drive circuit 22. And the driving current flowing in the FET 23 (driving current flowing in each exciting coil 21)
Voltage conversion is performed to generate a current value detection signal for each phase, and these are fed back to the deviation detection circuit 20. A resistor 24 for each phase.
And

When 4-bit drive current value setting data is output from the CPU circuit 13 of the central processing unit 12, D
The A / A converter circuit 15 D / A converts this to generate a drive current value setting signal, and the deviation detection circuit 20 causes the deviation detection circuit 20 to determine the value of the drive current value setting signal and the resistances 24 and FETs 23. While comparing the current value detection signal for each phase fed back from the connection point with and generating the deviation signal indicating each deviation, each driving circuit 22 outputs each from the CPU circuit 13. A drive signal for each phase is generated based on the phase excitation pattern for each phase and the value of the deviation signal, and a drive current is supplied to each excitation coil 21 of the stepping motor 10 by the FET 23 for each phase. , Is rotated with a torque according to the value of the drive current.

Next, the drive current adjusting operation in this embodiment will be described with reference to the flow chart shown in FIG. First, when the power source of the image reading apparatus 1 is turned on (step ST0), it is checked by the CPU circuit 13 of the control board 9 whether an ON signal is output from the optical sensor 8 (step ST1). If the ON signal is not output from the sensor 8, it is determined that the position of the optical traveling body 4 is deviated from the position (initial position) corresponding to the mounting position of the optical sensor 8, and the stepping motor 10 A driving current is supplied in the driving pattern for homing, the optical traveling body 4 is driven to the initial position, and is stopped at this position (step ST2). After that, the CPU circuit 13 of the control board 9 stores the digital data stored in the RAM circuit 14 (for example, drive current value setting data indicating "0110").
And the excitation pattern for each phase is read (step ST3), and the drive current value setting data
The D / A converter circuit 15, the deviation detection circuit 20, and the drive circuit 22 for each phase are controlled according to the excitation pattern for each phase to generate a drive signal for each phase. , The conductivity of the FET 23 provided for each phase is controlled.

As a result, the FETs 23 start the supply of the drive current to the exciting coils 21 of the stepping motor 10, and the torque obtained by the stepping motor 10 starts the traveling of the optical traveling body 4. (Step ST4). Further, in parallel with this operation, the CPU circuit 13 of the control board 9 starts a time counting operation using a timer (step ST5), and the count value obtained by this time counting operation is a preset count value. Is checked (step ST6). When the count value obtained by the time counting operation of the timer reaches the set count value (step ST
6) The CPU circuit 13 of the control board 9 checks whether the optical sensor 8 outputs an off signal indicating that the optical traveling body 4 has moved away from the initial position (step ST7).

If the OFF signal is not output from the optical sensor 8, the CPU circuit 13 determines that the load torque of the optical traveling body 4 is larger than the torque obtained by the stepping motor 10. , D / A
The value of the drive current value setting data supplied to the converter circuit 15 is a preset value (for example, 0001)
Is incremented by 1 to increase the value of the drive current supplied to the stepping motor 10 (step ST
8). After that, the driving operation of the optical traveling body 4 and the increase operation of the drive current described above are repeated, and the optical traveling body 4 is separated from the initial position within a predetermined time after the driving of the optical traveling body 4 is started. When an off signal is output from the optical sensor 8 (steps ST4 to ST8), the CPU circuit 1
This is detected by 3, and the current value (driving current value setting data indicating the optimum value) of the driving current value setting data supplied to the D / A converter circuit 15 is the RAM circuit 1
4 (step ST9) and put into a standby state (step ST10).

After that, every time the reading start switch is operated, the drive current value setting data indicating the optimum value stored in the RAM circuit 14 by the CPU circuit 13 of the control board 9 and the drive pattern for each phase. Are read out, and the stepping motor 10 is driven based on the drive current value setting data indicating these optimum values and the drive pattern for each phase, and the optical running body 4 causes the contact glass 3 to contact.
The image of the document 5 placed on the top is read. As described above, in this embodiment, when the image reading apparatus 1 is started up, it is checked whether the optical traveling body 4 has been driven to a predetermined place within a predetermined time, and the optical traveling body 4 is checked based on the check result. The driving current value of the stepping motor 10 that drives the optical traveling body 4 is adjusted so that the stepping motor 10 generates a torque that is slightly larger than the load torque of the optical traveling body 4. Even if the load torque of No. 4 changes, the stepping motor 10 is driven by a drive current of a magnitude corresponding to this, and thereby the optical traveling body 4 is caused to travel with the minimum drive torque corresponding to the load torque. The low vibration of the optical traveling body 4 can be prevented.

FIG. 4 is a sectional view showing a second embodiment of the image reading apparatus according to the present invention. Image reading device 3 shown in this figure
0 is an image reading unit 32 that reads an image of the set original document 31, and image data output from the image reading unit 32, and forms a toner image corresponding to the image data on a designated sheet, When the torque adjustment instruction of the stepping motor 34 is input, the reference image data stored in the image reading unit 32 is supplied to the image forming unit 33 to output the reference image. After the paper (reference image paper) on which is printed is discharged, the image reading unit 32 reads the image of the reference image paper while switching the value of the drive current for the stepping motor 34, and the drive that can be read correctly. The minimum current value of the current (the optimum drive current value) is stored, and thereafter, the stepping motor 34 is driven by the drive current having the optimum drive current value. , Reads the document image.

The image reading unit 32 is arranged in the casing 35, a casing 35 formed in a rectangular shape, a contact glass 36 fitted in an opening formed in the upper portion of the casing 35, and a contact glass 36. Guide rail (not shown)
Optical traveling body 3 configured to be movable in the sub-scanning direction
7, a light source 38 disposed on the optical traveling body 37 and illuminating the original 31 placed on the contact glass 36, and a light source 38 disposed on the optical traveling body 37 to emit light from the original 31 (optical A reflection mirror 39 that reflects an image) and makes it incident on a light receiving element 60 (see FIG. 6);
And an optical sensor 40 which is arranged inside the housing 35 and which detects an optical signal when the optical carriage 37 is at the origin (initial position) of the document scanning and outputs an ON signal. A control board 41 for controlling the operation of each part constituting the device based on the stored program, and a torque arranged according to the value of the drive current output from the control board 41, which is arranged in the housing 35. The optical traveling body 37 is provided with a stepping motor 34.

When a torque adjustment instruction for the stepping motor 34 is input, the reference image data stored in the control board 41 is read out and supplied to the image forming section 33 to print out the reference image paper. After that, when the reference image paper is set on the contact glass 36, the image of the reference image paper can be read correctly by switching the value of the drive current for the stepping motor 34 by the control board 41. The minimum possible drive current (drive current value) is obtained and stored, and thereafter, the stepping motor 34 is driven by the drive current having this drive current value to read the original image.

Further, the image creating section 33 takes in the reference image data and the original image data output from the image reading section 32, and prints the toner corresponding to the reference image data and the original image data on a designated paper. The image reading unit 32 includes a toner image forming mechanism 42 that forms an image and a fixing mechanism 43 that heats a sheet on which a toner image is formed by the toner image forming mechanism 42 while applying pressure.
When the reference image data or original image data is output from the device, capture it, form a toner image corresponding to the reference image data or original image data on the specified paper, fix it, and then fix it outside the machine. Eject the paper.

Next, the control board 41 provided in the image reading section 32 will be described with reference to the block diagram shown in FIG. 5 and the block diagram shown in FIG. As shown in these figures, the control board 41 includes a stepping motor control unit 44 that controls driving of the stepping motor 34.
And an image processing unit 45 that performs an operation of reading a document image, an operation of outputting a reference image, an operation of comparing each image, and the like, and a central processing unit 46 that controls operations of the image processing unit 45, the stepping motor control unit 44, and the like. When the operation unit 29 provided on the housing 35 is operated and a torque adjustment instruction of the stepping motor 34 is input, the central processing unit 46 stores it in the image processing unit 45. The reference image data stored in the image creating section 33.
Then, a sheet on which the reference image is printed (reference image sheet) is created and ejected, and then the stepping motor control unit 4
4 is controlled to switch the value of the drive current for the stepping motor 34, and the image data obtained by reading the image of the reference image paper by the image processing unit 45 is compared with the reference image data. Minimize the difference,
Further, a current value (driving current value) of the driving current that minimizes the torque of the stepping motor 34 is obtained and stored, and thereafter, the stepping motor 34 is driven by the driving current having this driving current value to obtain the original document. Make the image read.

In this case, the central processing unit 46 has a CPU circuit 47 for performing various control processing, data processing, etc. based on a preset program, and a work area for various processing executed by the CPU circuit 47. And a RAM circuit 48 used as a data storage area, and controls the stepping motor control unit 44 and the image processing unit 45 on the basis of a preset program to perform a specified operation. Let me do it. Further, the stepping motor control unit 44 outputs the 4-bit drive current value setting data output from the CPU circuit 47 to the D / A.
The D / A converter circuit 49 for converting and generating the drive current value setting signal, and the non-inverting input terminal
An operational amplifier 50 that receives the drive current value setting signal output from the converter circuit 49, a resistor 51 that pulls down the non-inverting input terminal of the operational amplifier 50, and a feedback current value detection signal that is the inverting input terminal of the operational amplifier 50. And a drive current value setting signal output from the D / A converter circuit 49, which is composed of an input resistor 52 and a feedback resistor 53 that connects the inverting input terminal and the output terminal of the operational amplifier 50. A deviation detection circuit 54 that compares the current value detection signal and generates a deviation signal according to the difference between them.

Further, the stepping motor controller 4
4 is for driving each exciting coil 55 of the stepping motor 34 with a constant current based on the phase exciting pattern for each phase outputted from the CPU circuit 47 and the deviation signal outputted from the deviation detecting circuit 54. A drive circuit 56 for each phase that generates a necessary drive signal and a drive current for each exciting coil 55 of the stepping motor 34 by conducting at a conduction rate corresponding to the value of the drive signal output from each drive circuit 56. And the drive current flowing in the FET 57 (drive current flowing in each exciting coil 55)
Voltage conversion is performed to generate a current value detection signal for each phase, and these are fed back to the deviation detection circuit 54. The resistor 58 for each phase.
And

When 4-bit drive current value setting data is output from the CPU circuit 47 of the central processing unit 46, the D / A converter circuit 49 outputs the drive current value setting data to the D / A converter circuit 49.
A conversion is performed to generate a drive current value setting signal, and
The deviation detection circuit 54 compares the value of the drive current value setting signal with the current value detection signal for each phase fed back from the connection point between each resistor 58 and each FET 57, and each deviation between them. While generating the deviation signal indicating the above, the driving circuit 56 generates the driving signal for each phase based on the phase excitation pattern for each phase output from the CPU circuit 47 and the value of the deviation signal. FET57 for each phase
As a result, each exciting coil 5 of the stepping motor 34 is
5 is supplied with a drive current, and this is rotated with a torque according to the value of the drive current.

Further, the image processing unit 45 takes in the read data output from the light receiving element 60 while the optical traveling body 37 is traveling, and reads the reference image paper set on the contact glass 36. When a read image processing circuit 61 for generating image data or an image of an original 31 and supplying it to the image creating unit 33 and the reference image data are stored and a torque adjustment instruction for the stepping motor 34 is input. A memory circuit 62 that reads the reference image data and supplies the reference image data to the image creating unit 33 and the like, and a reference image data and the read image output from the memory circuit 62 when a torque adjustment instruction for the stepping motor 34 is input. Image data of the reference image paper output from the processing circuit 61 is compared to generate image error data indicating these differences, Les and an image comparison circuit 63 supplies to the CPU circuit 47.

Then, when a torque adjustment instruction for the stepping motor 34 is input and a read command is output from the CPU circuit 47, the reference image data stored in the memory circuit 62 is read out and the reference image data is read out. When the comparison command is output from the CPU circuit 47 with the reference image paper set on the contact glass 36 after being supplied to the unit 33, the read image processing circuit 61 outputs the comparison command from the light receiving element 60. While the read data is taken in and the image data of the reference image paper is generated, the image comparison circuit 63 compares the reference image data stored in the memory circuit 62 with the image data, and the difference between them is obtained. To generate image error data
This is supplied to the CPU circuit 47. After this, the C
When an instruction to read an original image is output from the PU circuit 47, the read image processing circuit 61 causes the light receiving element 60 to operate.
The read data output from the
Image data is generated and is supplied to the image creating unit 33.

Next, the drive current adjusting operation in this embodiment will be described with reference to the flowchart shown in FIG. 7 and the flowchart shown in FIG. First, with the image reading device 30 powered on, the operation unit 2
9 is operated and a torque adjustment instruction for the stepping motor 34 is input (step ST11), the image reading unit 3
The CPU circuit 47 of the central processing unit 46 provided in the unit 2 controls the memory circuit 62 of the image processing unit 45,
The reference image data stored in the memory circuit 62 is read out and supplied to the image creating section 33 (step ST12). Then, the image creating unit 33 takes in the reference image data output from the image reading unit 32, forms a toner image corresponding to the reference image data on the designated sheet, and fixes the toner image. It is ejected outside.

Next, after the operator picks up the sheet on which the reference image data is formed (reference image sheet) and sets it on the contact glass 36, the operating section 29 is operated to operate the torque of the stepping motor 34. When the adjustment instruction is input, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32 causes the RAM
The drive current value setting data (first data) stored in the circuit 48 and the excitation pattern for each phase are read out, and according to the drive current value setting data and the excitation pattern for each phase, The D / A converter circuit 49, the deviation detection circuit 54, and the drive circuit 56 for each phase are controlled to generate a drive signal for each phase, and the FET 57 provided for each phase is generated by each of these drive signals. Is controlled (step ST13). As a result, the FETs 57 start to supply the drive current to the exciting coils 55 of the stepping motor 34, and the torque obtained by the stepping motor 34 causes the optical traveling body 37 to start traveling.

In parallel with this operation, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32.
The read image processing circuit 61 of the image processing unit 45 is controlled to process the read data output from the light receiving element 60, and the image data of the reference image paper set on the contact glass 36 is generated. (Step ST14), the image comparison circuit 63 compares the reference image data stored in the memory circuit 62 with the image data to generate image error data indicating the difference between them, which is the first image. RA as error data
It is stored in the M circuit 48 (step ST15).

Then, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32 causes the RAM circuit 4 to operate.
The drive current value setting data (first data) stored in 8 is incremented by a preset value to generate new drive current value setting data (second data) (step ST16). After that, by the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32,
The excitation pattern for each phase stored in the RAM circuit 48 is read out, and the excitation pattern for each phase,
According to the drive current value setting data (second data),
The D / A converter circuit 49, the deviation detection circuit 54, and the drive circuit 56 for each phase are controlled to generate a drive signal for each phase, and the FET 57 provided for each phase is generated by each of these drive signals. The conductivity rate of is controlled. As a result, the stepping motor 34 is controlled by each of these FETs 57.
The drive current is started to be supplied to each exciting coil 55, and the traveling of the optical traveling body 37 is started by the torque obtained by the stepping motor 34.

In parallel with this operation, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32.
The read image processing circuit 61 of the image processing unit 45 is controlled to process the read data output from the light receiving element 60, and the image data of the reference image paper set on the contact glass 36 is generated. (Step ST17), the image comparison circuit 63 compares the reference image data stored in the memory circuit 62 with the image data to generate image error data indicating the difference between them, which is the second image. RA as error data
It is stored in the M circuit 48 (step ST18).

Then, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32 causes the RAM circuit 4 to operate.
The drive current value setting data (first data) stored in 8 is decremented by a preset value to generate new drive current value setting data (third data) (step ST19). After that, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32 reads the excitation pattern for each phase stored in the RAM circuit 48, and the excitation pattern for each phase. And the drive current value setting data (third data)
The A / A converter circuit 49, the deviation detection circuit 54, and the drive circuit 56 for each phase are controlled to generate a drive signal for each phase. With these drive signals, the FET 57 provided for each phase is controlled. The conductivity is controlled. As a result, the FET 57 starts supplying the drive current to the exciting coils 55 of the stepping motor 34.
By the torque obtained by this stepping motor 34,
The traveling of the optical traveling body 37 is started.

In parallel with this operation, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32.
The read image processing circuit 61 of the image processing unit 45 is controlled to process the read data output from the light receiving element 60, and the image data of the reference image paper set on the contact glass 36 is generated. (Step ST20), the image comparison circuit 63 compares the reference image data stored in the memory circuit 62 with the image data to generate image error data indicating the difference therebetween, which is the third image. RA as error data
It is stored in the M circuit 48 (step ST21).

When the collection operation of these image error data is completed, the central processing unit 4 provided in the image reading unit 32.
The CPU circuit 47 of No. 6 reads out the first to third image error data stored in the RAM circuit 48 and compares the values of these first to third image error data with each other (step ST22). ST24), if the value of the first image error data is the smallest, the value of the drive current value setting data (first data) corresponding to this first image error data is the optimum current value for driving the stepping motor 34. Is determined to be stored in the RAM circuit 48 (step ST27), and if the value of the second image error data is the smallest, the drive current value setting data (second data) corresponding to the second image error data is stored. The value is the stepping motor 34.
Is determined to be the optimum current value for driving the
It is stored in the M circuit 48 (step ST25), and the third
If the value of the image error data is the smallest, the value of the drive current value setting data (third data) corresponding to the third image error data is determined to be the optimum current value for driving the stepping motor 34, and this value is determined. It is stored in the RAM circuit 48 (step ST26).

Thereafter, the original 3 is placed on the contact glass 36.
Every time 1 is set and a document reading command is input from the operation unit 29, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32 stores the optimum value stored in the RAM circuit 48. Drive current value setting data indicating various current values and the excitation pattern for each phase are read out, and the D / A converter circuit 49 and the deviation are set according to the drive current value setting data and the excitation pattern for each phase. The detection circuit 54 and the drive circuit 56 for each phase are controlled to generate a drive signal for each phase, and the conduction rate of the FET 57 provided for each phase is controlled by each of these drive signals.
As a result, the FETs 57 start to supply the drive current to the exciting coils 55 of the stepping motor 34, and the torque obtained by the stepping motor 34 causes the optical traveling body 37 to start traveling.

In parallel with this operation, the CPU circuit 47 of the central processing unit 46 provided in the image reading unit 32.
The read image processing circuit 61 of the image processing unit 45 is controlled to process the read data output from the light receiving element 60, and the image data of the document set on the contact glass 36 is generated. This is output terminal. Output, or supplied to the image creating unit 33 and printed out.

As described above, in this embodiment, when the torque adjustment instruction of the stepping motor 34 is input,
After the reference image data stored in the image reading unit 32 is supplied to the image creating unit 33 to eject the paper on which the reference image is printed (reference image paper), the image reading unit 32 causes the stepping motor 34 to operate. While switching the value of the drive current, the image on the reference image paper is read, and the minimum current value (optimum drive current value) of the drive current that can be correctly read is stored, and thereafter, the drive having the optimum drive current value is stored. Since the stepping motor 34 is driven by the electric current to read the original image,
Even if the load torque of the optical traveling body 37 changes due to changes over time, the stepping motor 34 is driven by a drive current of a magnitude corresponding to this, and thereby a minimum drive torque corresponding to the load torque is obtained. Vibration of the optical traveling body 37 can be prevented by traveling the optical traveling body 37.

FIG. 9 is a sectional view showing a third embodiment of the image reading apparatus according to the present invention. Image reading device 7 shown in this figure
Reference numeral 0 denotes an enclosure 71 formed in a rectangular shape, a contact glass 72 fitted in an opening formed in the upper portion of the enclosure 71, and a guide rail (not shown) arranged in the enclosure 71. The optical traveling body 73 configured to be movable in the sub-scanning direction, and the light source 75 for illuminating the document 74 placed on the optical traveling body 73 and placed on the contact glass 72. And the optical traveling body 73
The optical traveling body 73 is disposed on the optical traveling body 73 and the reflecting mirror 76 that is arranged above and reflects the light (optical image) from the original document 74 and makes it incident on a light receiving element (not shown). When traveling, the vibration measuring element 77 that detects the vibration and generates a vibration detection signal, and the optical traveling body 73, which is arranged in the casing 71, is at the original scanning origin (initial position). At this time, an optical sensor 78 that detects this and outputs an ON signal, and a control board 79 that is disposed in the housing 71 and that controls the operation of each unit that constitutes the device based on a preset program. The stepping motor 80 is disposed inside the housing 71 and drives the optical traveling body 73 with a torque according to the value of the drive current output from the control board 79. When the power of the image reading device 70 is turned on, the current value of the drive current for the stepping motor 80 is sequentially switched, and the optimum current value of the drive current (drive Current value),
This is stored, and thereafter, the stepping motor 80 is driven by the drive current having this drive current value, and the optical traveling member 73 is driven.
While traveling, the image of the document 74 set on the contact glass 72 is read to generate image data.

Next, the control board 79 will be described in detail with reference to the block diagram shown in FIG. As shown in this figure, the control board 79 controls the stepping motor controller 8 for controlling the driving of the stepping motor 80.
1 and a central processing unit 82 for controlling the operations of the stepping motor control unit 81 and the like, and the stepping motor 80 when the image reading device 70 is powered on.
The value of the drive current supplied to the optical traveling body 73 is sequentially switched to check the vibration value of the optical traveling body 73 while the optical traveling body 73 is traveling, and the vibration of the optical traveling body 73 is minimized based on the check result. The optimum current value of the drive current that can be obtained is calculated and stored, and thereafter, the stepping motor 80 is driven by the drive current having the optimum drive current value.
Is driven to drive the optical traveling body 73 to read the image of the document 74 set on the contact glass 72 and generate image data.

In this case, the central processing unit 82 carries out various control processing, data processing, etc. on the basis of a preset program while taking in the vibration detection signal output from the vibration measuring element 77 at the analog port. The stepping motor control section is provided with a CPU circuit 83 to be executed and a RAM circuit 84 used as a work area and a data storage area for various processes executed by the CPU circuit 83, based on a preset program. 8
The optical traveling body 73 is controlled on the basis of the process of controlling 1 to perform a designated operation and the output of the vibration measuring element 77.
The optimum current value of the drive current that can minimize the vibration of is calculated and stored.

Further, the stepping motor controller 81
Is a D / A converter circuit 85 for D / A converting 4-bit drive current value setting data output from the CPU circuit 83 to generate a drive current value setting signal; / A converter circuit 85 outputs an operational amplifier 86 for receiving a drive current value setting signal, a resistor 87 for pulling down the non-inverting input terminal of the operational amplifier 86, and a fed back current value detection signal for inverting the operational amplifier 86. The D / A is composed of an input resistor 88 that leads to an input terminal and a feedback resistor 89 that connects the inverting input terminal and the output terminal of the operational amplifier 86.
A deviation detection circuit 90 that compares the drive current value setting signal output from the converter circuit 85 with the current value detection signal and generates a deviation signal according to the difference therebetween is provided.

Further, the stepping motor controller 8
1 is to drive each exciting coil 91 of the stepping motor 80 with a constant current based on the phase excitation pattern for each phase output from the CPU circuit 83 and the deviation signal output from the deviation detecting circuit 90. A drive circuit 92 for each phase that generates a necessary drive signal, and a drive current is supplied to each exciting coil 91 of the stepping motor 80 by conducting at a conduction rate corresponding to the value of the drive signal output from each drive circuit 92. Current flowing through the FET 93 (driving current flowing through each exciting coil 91)
Voltage conversion is performed to generate a current value detection signal for each phase, and these are fed back to the deviation detection circuit 90. The resistor 94 for each phase.
And

When the CPU circuit 83 of the central processing unit 82 outputs 4-bit drive current value setting data, D
The A / A converter circuit 85 D / A-converts this to generate a drive current value setting signal, and the deviation detection circuit 90 causes the value of the drive current value setting signal, the resistances 94, and the FETs 93 to be generated. The current value detection signal for each phase fed back from the connection point with and is compared to generate a deviation signal indicating each deviation, and each driving circuit 92 outputs each from the CPU circuit 83. A drive signal for each phase is generated based on the phase excitation pattern for each phase and the value of the deviation signal, and a drive current is supplied to each excitation coil 91 of the stepping motor 80 by the FET 93 for each phase. , Is rotated with a torque according to the value of the drive current.

Next, the drive current adjusting operation in this embodiment will be described with reference to the flowchart shown in FIG. 11 and the flowchart shown in FIG. First,
If the image reading device 70 is powered on (step ST
30), the CPU circuit 83 of the central processing unit 82 checks whether or not the ON signal is output from the optical sensor 78 (step ST31). If the ON signal is not output from the optical sensor 78, the optical traveling is performed. It is determined that the position of the body 73 is deviated from the position (initial position) corresponding to the mounting position of the optical sensor 78, and the driving current is supplied to the stepping motor 80 in the driving pattern for homing, The optical traveling body 73 is driven to the initial position and is stopped at this position (step ST32). After that, the CPU circuit 83 of the central processing unit 82 reads the drive current value setting data (first data) stored in the RAM circuit 84 and the excitation pattern for each phase, and at the same time, these drive current values are read. The D / A converter circuit 85, the deviation detection circuit 90, and the drive circuit 92 for each phase are controlled according to the setting data and the excitation pattern for each phase to generate a drive signal for each phase.
FETs provided for each phase by these drive signals
The conductivity of 93 is controlled (step ST33).

As a result, the FET 93 starts to supply the driving current to the exciting coils 91 of the stepping motor 80, and the torque obtained by the stepping motor 80 starts the traveling of the optical traveling body 73. (Step ST34). Further, in parallel with this operation, the CPU circuit 83 of the central processing unit 82 takes in the vibration detection signal output from the vibration measuring element 77 provided in the optical traveling body 73, and this is taken as the first vibration data. , Are stored in the RAM circuit 84 (step ST35).

Next, the CPU circuit 83 of the central processing unit 82.
Thus, the drive current value setting data (first data) stored in the RAM circuit 84 is incremented by a preset value to generate new drive current value setting data (second data) (step ST36). After that, the CPU circuit 83 of the central processing unit 82 reads the excitation pattern for each phase stored in the RAM circuit 84, and the excitation pattern for each phase and the drive current value setting data ( Second data) and D /
The A converter circuit 85, the deviation detection circuit 90, and the drive circuit 92 for each phase are controlled to generate a drive signal for each phase. With these drive signals, the FET 93 provided for each phase becomes conductive. The rate is controlled. As a result, the driving current is started to be supplied to each exciting coil 91 of the stepping motor 80 by each of these FETs 93, and the traveling of the optical traveling body 73 is started by the torque obtained by the stepping motor 80 (step ST3).
7). Also, in parallel with this operation, C of the central processing unit 82
The PU circuit 83 takes in the vibration detection signal output from the vibration measuring element 77 provided in the optical traveling body 73, and stores it as the second vibration data in the RAM circuit 84 (step ST38).

Next, the CPU circuit 83 of the central processing unit 82.
Thus, the drive current value setting data (first data) stored in the RAM circuit 84 is decremented by a preset value to generate new drive current value setting data (third data) (step ST39). Thereafter, the CPU circuit 83 of the central processing unit 82 causes the R
The excitation pattern for each phase stored in the AM circuit 84 is read, and the D / A is set according to the excitation pattern for each phase and the drive current value setting data (third data).
The converter circuit 85, the deviation detection circuit 90, and the drive circuit 92 for each phase are controlled to generate a drive signal for each phase. With each of these drive signals, F provided for each phase is controlled.
The conductivity of the ET93 is controlled. As a result, each of these FETs 93 starts supplying a drive current to each exciting coil 91 of the stepping motor 80, and the torque obtained by the stepping motor 80 starts the traveling of the optical traveling body 73 (step ST40). ).
Further, in parallel with this operation, the CPU circuit 83 of the central processing unit 82 fetches the vibration detection signal output from the vibration measuring element 77 provided in the optical traveling body 73,
This is stored in the RAM circuit 84 as the third vibration data (step ST41).

When the collection operation of these vibration data is completed, the CPU circuit 83 of the central processing unit 82
The first to third vibration data stored in the RAM circuit 84 are read and the values of the first to third vibration data are compared with each other (steps ST42 to ST44),
If the value of the first vibration data is the smallest, the drive current value setting data (first data) corresponding to this first vibration data is determined to be the optimum current value for driving the stepping motor 80, and this is the RAM circuit. If it is stored in 84 (step ST47) and the value of the second vibration data is the smallest, the drive current value setting data (second data) corresponding to this second vibration data is optimum for driving the stepping motor 80. The current value is determined, and this is the RAM circuit 84.
(Step ST46), and if the value of the third vibration data is the smallest, the drive current value setting data (third data) corresponding to this third vibration data is the optimum current for driving the stepping motor 80. The value is determined and stored in the RAM circuit 84 (step ST4).
5).

Thereafter, the original 7 is placed on the contact glass 72.
4 is set and every time an original reading command is input, the CPU circuit 83 of the central processing unit 82 causes the RAM circuit 8
The drive current value setting data indicating the optimum current value and the excitation pattern for each phase, which are stored in 4, are read out, and according to the drive current value setting data and the excitation pattern for each phase, , D / A converter circuit 85, deviation detection circuit 90, and drive circuit 92 for each phase are controlled to generate drive signals for each phase. These drive signals are provided for each phase. The conductivity of the FET 93 is controlled. As a result, each of these FETs 93
The supply of the drive current to each exciting coil 91 of the stepping motor 80 is started, and the stepping motor 80
The traveling of the optical traveling body 73 is started by the torque obtained in step. Further, in parallel with this operation, the CPU circuit 83 of the central processing unit 82 processes the read data output from the light receiving element to generate the image data of the document 74 set on the contact glass 72. .

As described above, in this embodiment, when the image reading device 70 is powered on, the stepping motor 8
While sequentially switching the current value of the drive current with respect to 0,
The optimum current value of the drive current that can minimize the vibration of the optical traveling body 73 is obtained and stored, and then the stepping motor 80 is driven by the drive current having the optimum drive current value. , The original 7 set on the contact glass 72 while the optical traveling body 73 is traveling.
Since the image data of No. 4 is read and the image data is generated, even if the load torque of the optical traveling body 73 changes due to a change with time or the like, the stepping motor 80 having a drive current of a magnitude corresponding to the load torque changes. It is possible to prevent the low vibration of the optical traveling body 73 by driving the optical traveling body 73 with the minimum drive torque corresponding to the load torque.

[0056]

As described above, according to the present invention, in claim 1, when the image reading apparatus is started up, it is detected whether or not the optical traveling body is driven to a predetermined place within a predetermined time. Based on this detection, by controlling the drive current of the motor that drives the optical traveling body, even if the load torque of the optical traveling body changes due to changes over time, the drive current corresponding to this changes By driving the motor, the optical traveling body can be caused to travel with a minimum drive torque corresponding to the load torque, and low vibration of the optical traveling body can be prevented.

According to a second aspect of the present invention, the reference image pattern is stored in the memory provided in the apparatus, the reference image pattern is printed on the paper by the image forming unit, and then the optical running body is run. When reading the image of the paper on which the reference image pattern is printed, while changing the driving current of the motor stepwise, the image pattern obtained by this reading operation is compared with the reference image pattern,
The drive current that minimizes the difference between these patterns and that minimizes the torque generated by the motor can drive the motor to prevent vibration of the optical traveling body.

According to a third aspect of the present invention, a vibration measuring element is provided in the optical traveling body, and when the image reading device is started up,
When the optical traveling body is being driven, the vibration of the optical traveling body is measured by the vibration measuring element while changing the drive current of the motor stepwise, and the vibration of the optical traveling body is measured based on the measurement result. It is possible to prevent the vibration of the optical traveling body by driving the motor with a drive current that minimizes the torque and the torque generated by the motor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a block diagram showing a detailed circuit configuration example of a control board shown in FIG.

3 is a flowchart showing an example of drive current adjustment operation of the image reading apparatus shown in FIG.

FIG. 4 is a sectional view showing a second embodiment of the image reading apparatus according to the present invention.

5 is a block diagram showing a detailed circuit configuration example of the control board shown in FIG.

FIG. 6 is a block diagram showing a detailed circuit configuration example of the control board shown in FIG.

7 is a flowchart showing an example of drive current adjustment operation of the image reading apparatus shown in FIG.

8 is a flowchart showing an example of drive current adjustment operation of the image reading apparatus shown in FIG.

FIG. 9 is a sectional view showing a third embodiment of the image reading apparatus according to the present invention.

10 is a block diagram showing a detailed circuit configuration example of the control board shown in FIG.

11 is a flowchart showing an example of drive current adjustment operation of the image reading apparatus shown in FIG.

12 is a flowchart showing an example of drive current adjustment operation of the image reading apparatus shown in FIG.

[Explanation of symbols]

1 image reading device, 2 housing, 3 contact glass,
4 Optical traveling body, 5 originals, 6 light sources, 7 reflection mirrors,
8 optical sensor, 9 control board, 10 stepping motor, 11 stepping motor control section, 12 central processing section, 13 CPU circuit, 14 RAM circuit, 15 D
/ A converter circuit, 16 operational amplifiers, 17 resistors,
18 resistance, 19 resistance, 20 deviation detection circuit, 21
Excitation coil, 22 drive circuit, 23 FET, 24 resistance, 29 operation unit, 30 image reading device, 31 document,
32 image reading unit, 33 image creating unit, 34 stepping motor, 35 casing, 36 contact glass, 3
7 Optical traveling body, 38 light source, 39 reflection mirror, 40
Optical sensor, 41 control board, 42 toner image forming mechanism, 43 fixing mechanism, 44 stepping motor control section, 45 image processing section, 46 central processing section, 47 CP
U circuit, 48 RAM circuit, 49 D / A converter circuit, 50 operational amplifier, 51 resistor, 52 resistor, 53
Resistance, 54 Deviation detection circuit, 55 Excitation coil, 56
Drive circuit, 57 FET, 58 resistance, 60 light receiving element, 61 read image processing circuit, 62 memory circuit, 6
3 image comparison circuit, 70 image reading device, 71 case, 7
2 contact glass, 73 optical traveling body, 74 document, 75 light source, 76 reflection mirror, 77 vibration measuring element, 78 optical sensor, 79 control board, 80 stepping motor, 81 stepping motor control section, 8
2 central processing unit, 83 CPU circuit, 84 RAM circuit,
85 D / A converter circuit, 86 operational amplifier, 87
Resistance, 88 resistance, 89 resistance, 90 deviation detection circuit, 91 excitation coil, 92 drive circuit, 93 FE
T, 94 resistance

Claims (3)

[Claims] 1. An image reading apparatus for reading an image of an original while an optical traveling body is driven by using a motor controlled by constant current control as a power source, and a current value of a drive current supplied to the motor is gradually changed. While switching, the motor is operated, and the driving force obtained by the motor is used to drive the optical traveling body to check the traveling state of the optical traveling body, and the optical traveling body is checked based on the check result. An image reading apparatus characterized by determining a current value of a drive current capable of generating a minimum torque required for driving. 2. An image reading device for reading an image of an original while driving an optical traveling body using a motor controlled by constant current control as a power source, and supplying a prestored reference image pattern to an image forming section. Then, the reference image paper on which the reference image pattern is printed is ejected from the image creating section, and the current value of the drive current supplied to the motor is stepwise switched while the reference image paper is set. However, the image data of the reference image paper obtained by running the optical traveling body while driving the optical traveling body with the driving force obtained by the motor while operating the motor, and the reference image. Image error data indicating these errors is generated by comparing with the pattern, and based on each of these image error data, the image data of the reference image paper and The reference obtains a current value of the image pattern and the smallest and may drive current, the image reading apparatus characterized by a current value of the drive current supplied to the current value to the motor. 3. An image reading apparatus for reading an image of an original while an optical traveling body is driven by using a motor controlled by constant current control as a power source, and a current value of a drive current supplied to the motor is gradually changed. While switching, the motor is operated, and the driving force obtained by the motor is used to drive the optical traveling body while checking the value of the vibration detection signal output from the vibration measuring element provided on the optical traveling body. An image reading device is characterized in that a current value of a drive current capable of driving the optical traveling body with the least vibration is determined based on the check result.