JP3508701B2 - Motor drive device and image forming apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving device and an image forming apparatus, and more specifically, for example, a motor driving device that constitutes a facsimile machine with a copying function and a stepping motor for conveyance by the motor driving device. And an image forming apparatus that operates.

[0002]

2. Description of the Related Art In recent years, a flatbed scanner (FBS) for reading a still image of an original placed on an original placing plate.
And a plurality of manuscript automatic reading units (AD) for conveying a plurality of manuscripts set on a manuscript table one by one and reading a motion image thereof.
F) and copy machines and facsimile machines with a copying function are becoming mainstream.

In such a facsimile machine with a copying function, a transport motor is provided in the ADF for transporting a document set on a document table, and a carriage is moved from a read start position to a read end position. FBS
A moving motor is provided in each.

A stepping motor is generally used for each motor used in a facsimile machine with a copying function, including these motors, in order to perform positioning with high accuracy. Then, each stepping motor is driven by a motor driver that drives the stepping motor based on a position information signal for specifying the rotor position of the stepping motor obtained from the MPU via a relatively long serial signal line. .

[0005]

By the way, the motor driver is provided near the stepping motor, and the length of the power line for supplying the drive current from the motor driver to the stepping motor is shortened. This is to suppress the influence of noise due to a large current flowing through the power line.

However, if the motor driver is provided near the stepping motor, the motor driver will be MPU.
Therefore, the serial signal line connecting them becomes long. As a result, the serial signal line is susceptible to noise such as static electricity.

In this way, when the serial signal line for inputting the position information signal from the MPU to the motor driver receives noise such as static electricity, the position information signal for designating the rotor position of the stepping motor is changed to static electricity or the like. There is a case where the stepping motor is damaged by noise and cannot be normally driven by the motor driver. That is, if the motor driver loses the position information signal due to noise such as static electricity, the rotor of the stepping motor becomes unstable, and the stepping motor cannot be controlled.

Therefore, for example, when the serial signal line of the transport motor for transporting the document receives noise such as static electricity, there is a problem that the document cannot be transported normally. Similarly, with respect to the stepping motors other than the transport motor, there is a problem that the control becomes impossible and a problem occurs.

The present invention has been made in view of such a problem, and an object thereof is to provide a motor drive device and an image forming apparatus capable of suppressing a defect due to step-out of a stepping motor. To do.

[0010]

In order to achieve the above object, in the invention described in claim 1, a motor driver for driving a stepping motor based on a position information signal for designating a rotor position of the stepping motor. In a motor drive device having a holding function, the position information signal is held and output to the motor driver, and when noise from the outside is received, all data included in the position information signal is invalidated and output to the motor driver. First holding means for converting the position information signal into a parallel signal;
The converter, a latch circuit for latching parallel position information signals, and a second converter for serially converting the latched position information signals and outputting the serialized position information signals to the motor driver. At least one of the converter, the latch circuit, and the second converter includes a reset terminal that is reset by noise input, and invalidates all data included in the position information signal based on the reset, This data is used to stop the stepping motor at the current position.

According to a second aspect of the invention, in the motor drive device according to the first aspect, the reset terminal is connected to the ground. According to the third aspect of the present invention, a stepping motor for conveying an original to read the image on the original, a reading unit for reading the image on the original, and image data obtained by the reading by the reading unit are provided. In an image forming apparatus provided with a recording means for recording on a recording paper, a stepping motor for conveyance is driven by the motor drive device according to claim 1 or 2.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which a motor drive device according to the present invention is embodied in a motor drive device which constitutes a facsimile machine with a copying function will be described below with reference to the drawings.

As shown in FIG. 1, the facsimile apparatus 11 having a copying function includes a document feeding section 12, a document placing section 13,
A reading unit 14, a recording paper supply unit 15, a recording unit 16 and a recording paper discharge unit 17 are provided.

The document feeder 12 is configured to feed a plurality of documents 21 (first
A document table 22 on which a document can be placed, a separation roller 23 that separates and supplies the documents 21 on the document table 22 one by one, a plurality of feeding rollers 24 that feeds the separated document 21, and the feeding rollers 24. A transparent plate 25 on which the printed document 21 passes over the upper surface and a document discharge table 26 for stocking the discharged document 21 are provided. Further, the document feeding unit 12 includes a stepping motor M1 (see FIG. 2) for conveyance for rotating the separation roller 23 and the feeding roller 24.

The document presence / absence sensor 27 is arranged to face the document table 22, and outputs a detection signal when the document 21 is placed on the document table 22. The document discharge sensor 28 is arranged so as to face the document discharge table 26, and the document 2 is placed on the document discharge table 26.
When 1 is discharged, a detection signal is output.

The document placing portion 13 has a document 21 (second
A transparent document placing plate 31 on which a document is placed, and a holding lid 3 which is arranged on the document placing plate 31 so as to be openable and closable.
2 and. Then, the document table 2 of the document feeding unit 12
2 and the document discharge table 26 are disposed on the pressing cover 32 of the document placing portion 13, and are opened and closed integrally with the pressing cover 32.

The reading unit 14 provides a light source 37 for irradiating the original 21 passing on the transparent plate 25 or the original 21 placed on the original placing plate 31 with light, and an optical path of reflected light from the original 21. It is provided with first to third mirrors 38 to 40 to be changed, and a moving mechanism 41 (see FIG. 2) for moving the light source 37 and the first to third mirrors 38 to 40. Further, the reading unit 1
Reference numeral 4 denotes a condenser lens 42 that converges light from the third mirror 40, and an image of the original 21 is read based on the light incident through the condenser lens 42, and the read image of the original 21 is output as an analog signal. And an image pickup device (CCD) 43 that operates.

As shown in FIG. 2, the moving mechanism 41 includes a pair of left and right large-diameter pulleys 44 and 45, a pair of left and right small-diameter pulleys 46 and 47, and a first hook mounted between the large-diameter pulleys 44 and 45. A belt 48 and a second belt 49 mounted between the small diameter pulleys 46 and 47 are provided. Furthermore, the moving mechanism 41
Is a first carriage 50 connected to the first belt 48.
And a second carriage 51 connected to the second belt 49.
And a stepping motor M2 for movement.

The diameters of the large-diameter pulleys 44 and 45 are twice as large as the diameters of the small-diameter pulleys 46 and 47. Further, the large-diameter pulley 44 and the small-diameter pulley 46 on the left side are integrally rotatably connected on the same axis and are operatively connected to the stepping motor M2. Further, the light source 37 and the first mirror 38 are supported on the first carriage 50, and the second mirror 39 and the third mirror 40 are supported on the second carriage 51.

Then, the large-diameter pulleys 44, 45 and the small-diameter pulleys 46, 47 are rotated by the stepping motor M2, so that the first and second carriages 50, 50 are conveyed through the first and second belts 48, 49. 51 is moved.
At this time, the first carriage 50 is moved at twice the moving speed of the second carriage 51. As a result, the first and second carriages 50 and 51 are, as shown in FIG. 1, an intermediate standby position P1, a reading position P2 of the first original document located directly below the translucent plate 25 and a document placing plate. The second document is moved and arranged at a reading start position P3 of the second document, which is located immediately below the reference end 31a of the document 31.

Further, the document feeding section 12 and the reading section 14 constitute an automatic multi-document reading section (ADF), and in the state where the first carriage 50 is moved to the reading position P2 of the first document, it is transparent. The image of the document 21 passing on the plate 25 is read.

Further, a flatbed scanner (FBS) is constituted by the document placing section 13 and the reading section 14, and the first carriage 50 is at the reading start position P3 of the second document, that is, the home of the flatbed scanner (FBS). After being moved to the position, the second document reading end position P
4, the image of the original 21 placed on the original placing plate 31 is read.

The recording paper supply unit 15 stores a plurality of recording papers 56 of a predetermined size in a stacked state (in this embodiment, 2 sheets are used).
Recording paper cassettes 57a and 57b.
In addition, the recording paper supply unit 15 includes the recording paper cassettes 57a and 5a.
Paper feed rollers 58a and 58b for feeding the recording paper 56 in 7b one by one toward the recording unit 16 and a guide plate 59 for guiding the feeding of the recording paper 56 are provided. In the present embodiment, recording papers 56 of different sizes are accommodated in the respective recording paper cassettes 57a and 57b. Further, the recording paper supply unit 15 includes a supply stepping motor M3 for rotating the paper supply roller 58a and a paper supply roller 58b.
Is provided with a stepping motor M4 for supply for rotating.

Recording paper size sensors 60a and 60b are provided in the recording paper cassettes 57a and 57b, respectively. When each of the recording paper cassettes 57a and 57b is inserted into a predetermined position, these recording paper size sensors 6
0a, 60b outputs a detection signal indicating the size of the recording paper 56 accommodated in each recording paper cassette 57a, 57b.

The recording unit 16 includes a photoconductor drum 68 having a photoconductive film on its outer peripheral surface, a charger 69 for uniformly charging the photoconductive film of the photoconductor drum 68 to a predetermined potential, and a photoconductor drum 68 on the photoconductive drum 68. An exposure device 70 that forms an electrostatic latent image and a developing device unit 71 that supplies toner to the electrostatic latent image on the photosensitive drum 68 to develop the electrostatic latent image are provided. The developing device unit 71 includes a toner case 71a for storing toner, a developing roller 71b for transferring the toner in the toner case 71a to the photosensitive drum 68, and the like.

The recording section 16 includes a feeding roller 72 for feeding the recording paper 56 to the photosensitive drum 68, and a transfer device 73 for transferring the toner image from the photosensitive drum 68 onto the recording paper 56. A fixing unit 74 for heating and fixing the toner image on the recording paper 56. Fixing unit 7
Reference numeral 4 includes a heating roller 74a having a heater therein, and a pressure roller 74b that is pressed against the heating roller 74a with the recording paper conveyance path interposed therebetween.

Further, the recording section 16 includes a feeding roller 72,
Photoconductor drum 68, developing roller 7 of developing unit 71
1b, a heating roller 74a of the fixing unit 74, a pressure roller 74b, and a paper discharge roller 77 of the recording paper discharge unit 17 are provided with a recording stepping motor M5.

The recording paper discharge section 17 is for recording the recorded recording paper 5
A discharge roller 77 for discharging 6 is provided, a guide plate 78 for guiding the discharge of the recording paper 56, and a discharge tray 79 for stocking the discharged recording paper 56.

Next, the electrical configuration of the facsimile apparatus 11 having a copying function configured as described above will be described with reference to FIG. As shown in FIG. 3, the facsimile device 11 with a copying function includes an MPU 81, a ROM 82, and a RAM.
83, original feeding unit 12, reading unit 14, recording paper feeding unit 1
5, a recording unit 16, an operation unit 84, a display unit 85, an image memory 86, a codec 87, a modem 88 and an NCU 89, and the units 12, 14 to 16 and 81 to 89 are connected to each other via a bus 91. .

The MPU 81 controls the operation of each part of the facsimile device 11 with a copying function. The ROM 82 stores various programs necessary for the operation of the facsimile device 11 with a copying function. The RAM 83 temporarily stores various data associated with the execution of the program.

The document feeding section 12 feeds the document 21 set on the document table 22. The reading unit 14 reads an image of the original 21 via the translucent plate 25 or the original placing plate 31, and outputs image data of the read image. The recording paper supply unit 15 supplies the recording paper 56 of a predetermined size to the recording unit 16 from the recording paper cassettes 57a and 57b selected according to the document size and the like. The recording unit 16 is composed of, for example, an electrophotographic printer, and records the received image data in the FAX operation and the image data of the image read by the reading unit 14 in the copy operation on the recording paper 56.

The operation unit 84 includes ten keys (including * and # keys) 84a for inputting a telephone number, a FAX number and the like,
Shortened key 84b for registering or sending a shortened number, one-touch key 84c for one-touch designation of a fax number registered in advance, start key 84d for starting a document reading operation, "communication (FA
X) ”mode or“ copy ”mode, and various operation keys such as a communication / copy key 84e and a setting key 84f for designating a recording paper cassette. LC
The display unit 85 including D or the like displays various information such as the operating state of the facsimile apparatus 11 with a copying function.

The image memory 86 temporarily stores the received image data and the image data read by the reading unit 14. The codec 87 band-compresses and encodes the image data of the image read by the reading unit 14 by the MH, MR, MMR, JBIG method or the like for transmission. or,
The codec 87 decodes the received image data.

The modem 88 uses the ITU-T recommendation T.264. 30 based on the facsimile transmission control procedure according to V.30. 1
7, V.I. 27 ter, V.I. The transmission / reception data is modulated and demodulated according to 29 or the like. The NCU 89 has a function of closing and opening the telephone line L and detecting a sending and receiving of a dial signal corresponding to the FAX number of the other party.

Next, a motor drive circuit 1 for driving a conveying stepping motor M1 used in the document feeding section 12.
00 will be described with reference to FIG. The reading unit 14
Used for the motor drive circuit 200 for driving the moving stepping motor M2 used in the above, the motor drive circuits 300, 400 for driving the supply stepping motors M3, M4 used for the recording paper supply unit 15, and the recording unit 16, respectively. The motor drive circuit 500 that drives the recording stepping motor M5 is the same as the motor drive circuit 100 that drives the stepping motor M1, and therefore description thereof is omitted.

As shown in FIG. 4, the motor drive circuit 100
Is provided for the stepping motor M1 and is
81, serial / parallel converter K11, latch circuit L
1, a parallel / serial converter K21 and a motor driver 101. In the motor drive circuit 100, the MPU 81 is provided near the recording unit 16 (see FIG. 1), and the other serial / parallel converter K11, the latch circuit L1, the parallel / serial converter K21, and the motor driver 101 are near the stepping motor M1. It is provided in. Therefore, the serial signal line W1 connecting the MPU 81 and the serial / parallel converter K11 has a relatively long wiring.

The stepping motor M1 of this embodiment is used.
Each of M5 to M5 is a hybrid type two-phase stepping motor, and includes an A-phase winding CA, a B-phase winding CB, and a rotor R. On the other hand, stepping motors M1 to
Motor drivers 101 to 105 for respectively driving M5
Are both current control type stepping motor drivers.

The MPU 81 outputs a position information signal for designating the rotor position of the stepping motor M1 to the serial / parallel converter K11 via the serial signal line W1. The position information signal includes the winding C of each phase of the motor.
It includes current value data for supplying a predetermined current to A and CB and a control signal for supplying a current to the windings CA and CB of each phase of the motor in a predetermined sequence.

The serial / parallel converter K11 is an MP
The position information signal from U81 is converted into parallel and output to the latch circuit L1. Also, serial / parallel converter K
11 has a reset terminal, and the reset terminal is connected to the ground. That is, when noise due to static electricity or the like is input to the reset terminal through the ground, the serial / parallel converter K11 is reset and the MPU
All data included in the position information signal input from 81 is invalidated and all values are set to “0”. In the present embodiment, the data of all “0” invalidated by the serial / parallel converter K11 becomes the same data as the data included in the position information signal for stopping the rotor R of the stepping motor M1 at the current position. ing.

The latch circuit L1 latches the position information signal converted in parallel by the serial / parallel converter K11. The parallel / serial converter K21 serially converts the position information signal latched by the latch circuit L1 and outputs it to the motor driver 101.

The motor driver 101 obtains electric power from a motor power source (not shown), and the parallel / serial converter K
Based on the position information signal serially converted in 21,
A predetermined current is supplied to the windings CA and CB of each phase of the stepping motor M1 in a predetermined sequence.

Next, the facsimile machine 11 with a copying function
In driving the stepping motors M1 to M5 by the motor driving circuits 100 to 500 respectively,
The operation when the serial signal lines W1 to W5, which respectively connect 1 and the serial / parallel converters K11 to K15, receive noise such as static electricity will be described. The operation of each of the motor drive circuits 200 to 500 is similar to that of the motor drive circuit 100.
Only the operation when the serial signal line W1 of 0 receives noise will be described.

The stepping motor M1 is driven by the motor drive circuit 100 so that the reading unit 14 in the facsimile apparatus 11 with a copying function reads the image on the original 21 and the original table 22 of the original feeding unit 12 is used. This is performed when the document 21 (first document) set at is fed to the reading unit 14.

When the original 21 is set on the original table 22 of the original feeding section 12 and the start key 84d is operated, an original detection signal is sent from the original presence sensor 27 to the MPU 81 based on the setting of the original 21. Is entered. Then,
A position information signal for moving the rotor R to a predetermined rotor position by supplying a predetermined current to the windings CA and CB of each phase of the stepping motor M1 in a predetermined sequence is M.
It is input from the PU 81 to the serial / parallel converter K11 via the serial signal line W1. Then, the position information signal is converted into parallel by the serial / parallel converter K11, the position information signal converted into parallel is latched by the latch circuit L1, and the latched position information signal is further converted into parallel / parallel. It is serially converted by the serial converter K21 and input to the motor driver 101.

Then, the parallel / serial converter K21
Based on the position information signal serially converted by the motor driver 101, a predetermined current is supplied from the motor driver 101 to the windings CA, CB of each phase of the stepping motor M1 in a predetermined sequence, and the rotor R is rotated by the rotor shown in FIG. It is moved from position X0 to rotor position X1. FIG. 5 shows the motor driver 10.
2 is a schematic diagram showing the operation of the rotor R when the stepping motor M1 is driven by the serial signal line W in FIG.
When 1 is normal without noise, the rotor R moves in the order of rotor positions X0 to Xn, as indicated by solid arrows in the figure.

Next, the rotor R of the stepping motor M1
If the serial signal line W1 receives noise due to static electricity or the like when the position information signal for moving the rotor position X1 to the rotor position X2 is input from the MPU 81 to the serial / parallel converter K11, Like In this case, since the serial signal line W1 receives noise due to static electricity or the like, the position information signal input to the serial / parallel converter K11 via the serial signal line W1 that receives the noise is affected by the noise. Then, the data included in the position information signal affected by the noise becomes erroneous data that is not normal data, and the position information signal including the erroneous data is input to the serial / parallel converter K11.

When the serial signal line W1 receives noise such as static electricity, noise such as static electricity is also input to the reset terminal of the serial / parallel converter K11 via the ground. Then, the serial / parallel converter K11 is reset, and the position information signal including the erroneous data input from the MPU 81 to the serial / parallel converter K11 via the serial signal line W1 is invalidated. That is, the values of all the data included in the position information signal are set to "0".

Then, the serial / parallel converter K11
A position information signal made up of data that is invalidated and all set to "0" is input to the latch circuit L1, and the position information signal is latched by the latch circuit L1. Then, the latched position information signal is converted into the parallel / serial converter K.
It is converted into serial at 21 and input to the motor driver 101.

Then, no current is supplied from the motor driver 101 to the windings CA and CB of each phase of the stepping motor M1 based on the position information signal consisting of the data all set to "0". Therefore, the stepping motor M1
Rotor R is stopped at the current position of rotor position X1.

Next, the rotor R of the stepping motor M1
Position information signal for moving the rotor to the rotor position X3 is M
When input from the PU 81 to the serial / parallel converter K11 (when no noise is received at this time),
The position information signal is converted into parallel by the serial / parallel converter K11. Then, the position information signal converted into parallel is latched by the latch circuit L1, the latched position information signal is converted into serial by the parallel / serial converter K21, and the motor driver 10
Input to 1.

Then, the parallel / serial converter K21
On the basis of the position information signal serially converted by the motor driver 101, a predetermined current is supplied from the motor driver 101 to the windings CA and CB of each phase of the stepping motor M1 in a predetermined sequence, and a chain line arrow in FIG. As shown by,
Is moved from the rotor position X1 to the rotor position X3.

Thereafter, similarly, the stepping motor M
One rotor R is moved to the next rotor position such as from rotor position X3 to rotor position X4, and further from rotor position X4 to rotor position X5.

Therefore, by moving the rotor R of the stepping motor M1 as described above, that is, by driving the stepping motor M1, the separating roller 23 and the feeding roller 24 are rotated, and the document table 22 is rotated. The originals 21 set at are fed one by one.

As described above in detail, according to this embodiment, the following actions and effects can be obtained. (1) When the serial signal lines W1 to W5 receive noise such as static electricity, the serial / serial lines are also connected via the ground.
Noise such as static electricity is input to the reset terminals of the parallel converters K11 to K15, and the serial / parallel converter K
11 to K15 are reset. Then, the position information signal including erroneous data input from the MPU 81 to the serial / parallel converters K11 to K15 via the serial signal lines W1 to W5 is invalidated, and the values of all the data included in the position information signal are invalidated. Are set to "0" respectively.

Data for stopping the rotor R of the stepping motors M1 to M5 at the current position,
A position information signal composed of data whose values are all "0" is latched by the latch circuits L1 to L5. Then, when the latched position information signal is serially converted by the parallel / serial converters K21 to K25 and input to the motor drivers 101 to 105, the motor drivers 101 to 105 output from the motor drivers 101 to 105 based on the position information signal. No current is supplied to the windings CA and CB of the respective phases of the stepping motors M1 to M5. Therefore, the stepping motors M1 to M1
The rotor R of M5 is stopped at the current position.

In other words, even if the data of the position information signal is rewritten into erroneous data due to noise such as static electricity, the erroneous data is all "0" data for stopping the rotor R at the current position. Therefore, the rotors R of the stepping motors M1 to M5 are stopped at the current position based on the data of all “0”. Therefore, the motors M1 to M5 are not driven based on the erroneous data.

Thereafter, the rotor R of each of the motors M1 to M5 is moved based on the next position information signal input from the MPU 81 to the serial / parallel converters K11 to K15 without receiving noise.

That is, when the serial signal lines W1 to W5 receive noise, only the data contained in the position information signal which has received the noise are serial / parallel converters K11 to K.
It is invalidated by the reset of 15, and the stepping motors M1 to M5 are stopped. Then, the stepping motors M1 to M5 are driven based on the subsequent normal position information signal. Therefore, the stepping motors M1 to M5
In the above, the position information signal only needs to be temporarily stopped between the time when the position information signal receives noise and the time when the normal position information signal is input, and its control is not disabled. Therefore, it is possible to suppress a defect due to step-out of the stepping motors M1 to M5.

(2) In addition, the document table 2 of the document feeding unit 12
As a defect due to step-out of the stepping motor M1 that feeds the document 21 (first document) set to 2 to the reading unit 14, there is image distortion when recording image data on the recording paper 56. That is, if the stepping motor M1 is stepped out and stopped during the feeding of the first original, the feeding of the first original is stopped. Here, at the time of feeding the first document, the reading unit 14
Then, the image on the first original is read and the image data of the image is stored in the image memory 86. Therefore, when the feeding of the first document is stopped, the predetermined image on the first document in the stopped state is continuously read by the reading unit 14, and the image data of the predetermined image is stored in the image memory 86. Will be done.

Therefore, when the image data read from the image memory 86 is subsequently recorded on the recording paper 56 by the recording unit 16, only the image data of the same image is recorded on the recording paper 56. That is, image data of an unintended image is recorded on the recording paper 56 instead of the regular image on the first document, and image distortion occurs. However, in the present embodiment, the stop of the stepping motor M1 for feeding the first document is temporary, so that extreme image distortion can be avoided.

(3) The position information signals input via the serial signal lines W1 to W5 are converted into parallel signals by the serial / parallel converters K11 to K15, respectively,
The position information signals converted into parallel are serially converted by the parallel / serial converters K21 to K25 and input to the motor drivers 101 to 105, respectively. That is, the number of signal lines is significantly reduced as compared with the case where the MPU 81 and the serial / parallel converters K11 to K15 are connected by parallel signal lines, respectively.
It is possible to reduce the size of the facsimile device 11 having a copying function, and thus reduce the cost. In particular, when a long signal line is required between the MPU 81 and the serial / parallel converters K11 to K15, the effect is remarkable.

The above embodiment can be modified and embodied as follows. Although the motor drivers 101 to 105 that perform serial communication are used in the above-described embodiment, the stepping motors M1 to M5 may be driven using a motor driver that performs parallel communication. According to this structure, the parallel / serial converters K21 to K25 can be omitted, so that the facsimile apparatus 11 having a copying function can be downsized and the cost can be reduced.

In the above embodiment, the MPU 81 and the serial / parallel converters K11 to K15 are connected to the serial signal line W.
1 to W5 respectively, but serial signal lines W1 to
Instead of W5, both may be connected by parallel signal lines.

Instead of obtaining the position information signal from the MPU 81, it may be embodied in a motor driving device equipped with a signal generating circuit for generating the position information signal. In the above embodiment, the facsimile machine 1 with a copying function
However, the invention may be embodied as a motor driving device that constitutes a copying machine.

In the above embodiment, when the reset terminals of the serial / parallel converters K11 to K15 are connected to the ground and noise such as static electricity is input to the reset terminals, the serial / parallel converters K11 to K15 are activated. Although all the data of "0" for resetting and stopping the rotor R of the stepping motors M1 to M5 at the current position is input to the latch circuits L1 to L5, the following may be adopted.

That is, the serial / parallel converters K11 to K11
Instead of K15, the latch circuits L1 to L5 may be provided with reset terminals, and the reset terminals may be connected to the ground. In this case, even if the position information signal including erroneous data is input from the serial / parallel converters K11 to K15 to the latch circuits L1 to L5, the latch circuits L1 to L5 are input.
When noise such as static electricity is input to the reset terminal of 5,
The latch circuits L1 to L5 are reset. The data of all "0" for stopping the rotor R of the stepping motors M1 to M5 at the current position is latch circuits L1 to L5.
Latched by the parallel / serial converters K21-K
25 is input.

Further, the serial / parallel converters K11 to K11.
Parallel / serial converters K21 to K instead of K15
25 may be provided with a reset terminal and the reset terminal may be connected to the ground. In this case, the latch circuits L1 to L5 to the parallel / serial converters K21 to
Even if a position information signal containing incorrect data is input to K25,
When noise such as static electricity is input to the reset terminals of the parallel / serial converters K21 to K25, the parallel / serial converters K21 to K25 are reset. And
The data of all "0" for stopping the rotor R of the stepping motors M1 to M5 at the current position is the motor driver 1.
01 to 105 are input.

Further, the serial / parallel converter K1
1 to K15 and the latch circuits L1 to L5 may be provided with reset terminals, respectively, and the reset terminals may be connected to the ground.

· Furthermore, the serial / parallel converter K
11 to K15 and parallel / serial converters K21 to K
It is also possible to provide reset terminals on both of 25 and connect the reset terminals to the ground.

It is also possible to provide reset terminals on both the latch circuits L1 to L5 and the parallel / serial converters K21 to K25, and connect the reset terminals to the ground.

Further, the serial / parallel converter K1
1 to K15, the latch circuits L1 to L5, and the parallel / serial converters K21 to K25 may all be provided with reset terminals, and the reset terminals may be connected to the ground.

In the above-described embodiment, noise such as static electricity is input to the reset terminals of the serial / parallel converters K11 to K15, and the serial / parallel converters K11 to K1.
When 5 is reset, the values of all the data included in the position information signal including erroneous data are set to "0", but the values of all the data may be set to "1", for example. In this case, the data of all “1” s invalidated by the serial / parallel converters K11 to K15 is the stepping motor M1.
The data must be the same as the data included in the position information signal for stopping the rotor R of M5 to the current position.

[0073]

[0074]

[0075]

Since the present invention is constructed as described above, it has the following effects. According to the invention described in each claim, it is possible to suppress a defect due to step-out of the stepping motor. Further, according to the first and second aspects of the present invention, it is possible to prevent the stepping motor from being driven based on erroneous data. Also,
According to the third aspect of the present invention, the image distortion when recording the image data on the recording paper is a defect due to the stepping out of the conveying stepping motor, but it is possible to avoid the extreme image distortion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a facsimile device having a copying function.

FIG. 2 is a partially enlarged cross-sectional view of a facsimile device with a copying function.

FIG. 3 is a block configuration diagram of a facsimile device with a copying function.

FIG. 4 is a schematic electric circuit diagram showing a configuration of a motor drive circuit.

FIG. 5 is a schematic diagram showing the operation of the rotor when the stepping motor is driven.

[Explanation of symbols]

Reference numerals 101 to 105 ... Motor drivers constituting respective motor drive devices, K11 to K15 ... Serial / parallel converters as first converters constituting respective motor drive devices, holding means and conversion means, K21 to K25 ... Respective motors A parallel / serial converter as a second converter constituting the driving device, the holding means and the converting means, L1
To L5 ... Latch circuits constituting a motor driving device and holding means, M1 to M5 ... Stepping motor, X0
~ Xn ... Rotor position, 14 ... Reading unit as reading means,
16 ... Recording unit as recording means, 11 ... Facsimile apparatus with copy function as image forming apparatus.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02P 8/00 G03G 21/14 H04N 1/00

Claims (3)

(57) [Claims] 1. A motor drive device having a motor driver for driving a stepping motor based on a position information signal for designating a rotor position of a stepping motor, the position information signal being held and output to the motor driver, and externally. A first converter for invalidating all data contained in the position information signal and outputting the invalidated data to the motor driver when the noise is received from the first converter. And a latch circuit for latching parallel position information signals, and a second converter for converting the latched position information signals into serial signals and outputting them to the motor driver. At least one of the circuit and the second converter includes a reset terminal that is reset by noise input, and The motor drive device that invalidates all the data included in the position information signal based on the reset of 1. and sets the data to stop the stepping motor at the current position. 2. The motor drive device according to claim 1, wherein the reset terminal is connected to the ground. 3. A stepping motor for transporting an original to read the image on the original, a reading unit for reading the image on the original, and image data obtained by the reading by the reading unit is recorded on a recording paper. An image forming apparatus comprising: a recording unit that drives a stepping motor for conveyance by the motor driving device according to claim 1 or 2.