JPH10129882A - Facsimile device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce drive torque at the time of reading a document or recording on a recording paper and reduce heat generation and noise of a motor by controlling drive torque of the stepping motor based on a conveyance condition of the document or recording paper. SOLUTION: A reception motor driver 4e rotates a reception motor 4d at high speed due to the control of a central processing part 1. This rotation is transmitted to a transfer roller to transfer recording paper from a paper supply tray at high speed. The recording paper which is transferred passes a transfer sensor and then reaches a recording part after a predetermined time elapses. A timer activated by a transfer detection sensor measures this predetermined time. When the central processing part 1 judges that recording paper reaches the recording part based on outputs of the timer, it controls conveyance speed of recording paper in accordance with communication speed and image data. That is, the reception motor driver lee reduces rotation speed of the reception motor 4d and reduces conveyance speed of recording paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus, and more particularly, to a facsimile apparatus using a stepping motor.
The present invention relates to motor drive control in a facsimile apparatus that conveys a document or recording paper.

[0002]

2. Description of the Related Art In a facsimile apparatus, it is necessary to convey a document or a recording sheet when reading a document or recording image data. Therefore, conventionally, a facsimile apparatus uses a stepping motor to perform this conveyance. FIG. 7 shows the relationship between the rotation speed and the driving torque when such a stepping motor is driven at a constant current.

When the motor driver performs a constant current drive for supplying a constant drive current to each phase of the stepping motor, the drive torque increases as the drive current increases. Further, even if the driving current supplied to the stepping motor is constant, the driving torque of the stepping motor is different if the rotation speed is different. That is, at the time of high-speed rotation, the driving torque is lower than at the time of low-speed rotation.

Here, in this type of facsimile apparatus, as shown in FIG. 8, generally, the fastest conveyance is performed when a document or a recording sheet is fed or discharged, while the document is being read or read. During the recording on the recording paper, the conveyance is performed at a lower speed. In addition, the load applied to the conveyance of the document or the recording paper is small during the transfer, becomes larger during the reading or the recording than during the transfer, and becomes larger than the reading or the recording during the discharge.

For this reason, when the stepping motor is driven at a constant current, the torque is minimized when the original or the recording paper is fed in, becomes larger during reading or recording, and becomes larger during ejection. Required. Therefore, when the stepping motor is driven, it is necessary to secure a sufficient driving torque even at the time of the repetition in which the driving torque is reduced and the discharge requiring the maximum torque is performed, in order to prevent the occurrence of step-out. .

However, when the stepping motor is driven at a constant current by a driving current capable of securing a sufficient driving torque even during discharging, the stepping motor is driven with an excessive torque during reading or recording. There is a problem that heat generation and noise increase. In such a facsimile machine,
When controlling the drive of the stepping motor, a 1-2-phase excitation (half-step) method is sometimes used in order to reduce the feed angle, improve the accuracy of conveyance, and improve the image quality.

However, when the 1-2-phase excitation method is employed, the holding power of the stepping motor differs between when the excitation is performed in one phase and when the excitation is performed in two phases. Angle unevenness occurs in the rotation of. For this reason, there has been a problem that the feed amount of the original or the recording paper varies, and the interval between scanning lines at the time of reading or recording varies, thereby deteriorating the image quality.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and by driving a stepping motor with an appropriate torque, heat generation and noise of the motor when reading a document or recording image data. The primary purpose is to reduce It is a second object of the present invention to generate a high-quality image with uniform line intervals by preventing uneven feeding of a document or recording paper.

[0009]

According to a first aspect of the present invention, there is provided a facsimile apparatus for conveying a document or recording paper using a stepping motor when reading a document or recording image data. The driving torque of the stepping motor is controlled based on the transport state of the document or the recording paper. Here, the transport state refers to the transport speed and the load that will be applied during transport.

A facsimile apparatus according to a second aspect of the present invention is the facsimile apparatus according to the first aspect of the present invention, wherein a motor control circuit for supplying a drive current to the stepping motor is provided for controlling the operation of an original or recording paper. The drive current of the stepping motor is changed based on the transport state. A facsimile apparatus according to the present invention described in claim 3 is a facsimile apparatus that drives a stepping motor by a 1-2-phase excitation method and conveys an original or a recording sheet, and generates a drive current during one-phase excitation. The configuration is such that the drive current is controlled to be larger than the drive current during two-phase excitation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows an example of the configuration of a facsimile apparatus according to the present invention. This facsimile machine 1
Reference numeral 0 denotes a central processing unit 1 (CPU), a transmission / reception unit 2, a document reading unit 3, an image recording unit 4, an operation unit 5, and a storage unit 6. The transmission / reception unit 2 includes a network control unit 2a (NCU) connected to the telephone line La and a modem 2b, and transmits and receives data to and from another terminal device via the telephone line La. .

In the original reading section 3, an image sensor 3a reads image data of the original while the original is conveyed by a transmission motor 3c. The read image data is subjected to predetermined processing by the image processing circuit 3b, and then read to the image memory 4b.
(DRAM). The transmission motor 3c is a stepping motor, and its drive control is based on a control signal from the central processing unit 1 based on the transmission motor driver 3d.
Do.

The image recording section 4 reproduces an image on the recording paper while conveying the recording paper such as cut paper (plain paper) by the receiving motor 4d. The image recorded in this way is read by the gate array 4c from the image data stored in the image memory 4b, and the thermal head 4a writes the data on the recording paper. The receiving motor 4d is a stepping motor, and its driving control is performed by a receiving motor driver 4e based on a control signal from the central processing unit 1.

An operation unit 5 includes a liquid crystal display 5a for performing various displays and an operation panel 5b for an operator to input.
The storage unit 6 includes a ROM 6a and a RAM
6b, and stores programs and data of the central processing unit 1. The central processing unit 1 communicates with each of the above blocks 2 via the address bus AB and the data bus DB.
The central processing unit 1 controls the entire facsimile machine 10.

FIG. 2 is a diagram showing an example of a conveying path of a document and a recording sheet in the facsimile apparatus 10 to which the present invention is applied. Hereinafter, a case where a recording sheet is conveyed and image data is recorded will be described as one embodiment. At the time of image data recording, first, the recording paper set on the paper feed tray Pt is fed into the transport path Pw by the feeding roller Ri. On the transport path Pw behind the running-in roller Ri, a movable detection piece of the running-in detection sensor Si is provided. This renormalization detection sensor Si
Is to detect the retraction of the recording paper by utilizing the push-up of the movable detection piece when the repelled recording paper passes. On the recording paper that has passed through the reproducing sensor Si, the ink is melt-transferred from the thermal transfer ribbon TR in a recording unit constituted by the thermal head 4a and the platen roller Rp, and an image is written.

A movable detection piece of the discharge detection sensor So is provided on the conveyance path Pw behind the recording section. The discharge detection sensor So detects the discharge of the recording paper by detecting the passage of the recording paper by the movable detection piece, similarly to the case of the retraction sensor Si. This discharge detection sensor So
A discharge roller Ro is provided further behind the facsimile machine 10 to discharge the recording paper out of the facsimile apparatus 10.

When recording image data on recording paper at the time of an incoming call or copying, first, under the control of the central processing unit 1, the receiving motor driver 4e rotates the receiving motor 4d at high speed. This rotation is transmitted to the rewind roller Ri, and the recording paper is repelled from the paper feed tray at a high speed. The fed recording paper reaches the recording unit when a predetermined time elapses after passing through the feeding detection sensor Si. This predetermined time is counted in, and a timer (not shown) started by the detection sensor Si measures it. When the central processing unit 1 determines that the recording paper has reached the recording unit based on the output of the timer, the central processing unit 1 controls the conveyance speed of the recording paper according to the communication speed and the image data. That is, the receiving motor driver 4e lowers the rotation speed of the receiving motor 4d and lowers the transport speed of the recording paper.

At this time, the receiving motor driver 4e lowers or increases the driving current supplied to the receiving motor 4d in accordance with the balance between the lowering of the transport speed and the increase of the load, so that the driving torque of the receiving motor 4d is reduced. Make it bigger than time. When one page of image data is recorded in this way and a page break code in the image memory 4b is detected, the receiving motor driver 4e increases the rotation speed of the receiving motor 4d and discharges the recording paper by high-speed conveyance. I do.
At this time, the receiving motor driver 4e increases the driving current supplied to the receiving motor 4d according to the increase in the transport speed and the load, so that the driving torque of the receiving motor 4d can be made larger than that during recording.

Thereafter, if a predetermined time has passed after the end of the recording paper has passed the discharge detection sensor So, the recording paper is
The paper is completely discharged from the facsimile machine 10. This predetermined time is measured by a timer (not shown) started by the discharge detection sensor So. The central processing unit 1 controls the receiving motor driver 4e based on the output of the timer to stop the discharge of the recording paper or to start taking in the next recording paper.

FIG. 3 is a diagram showing a configuration example of a main part of the receiving motor driver 4e, which is a constant current chopper type driving circuit for supplying a predetermined driving current to each phase of the stepping motor. This drive circuit includes a transistor Tr as switching means for controlling a drive current Id supplied to each phase of the motor winding L, a current detection resistor R for detecting a current flowing through the motor winding L as a voltage level, Reference voltage Vo and current detection resistor R supplied from central processing unit 1
, A pulse width control circuit WC for controlling the transistor Tr based on an output of the voltage comparison circuit CP, and a motor winding L and a transistor Tr. It is composed of diodes D1 and D2 to be prevented and a Zener diode D3.

When the value of the current flowing through the motor winding L increases, the voltage between the terminals of the current detection resistor R increases, and the reference voltage V
o, the pulse width control circuit WC turns on the transistor T
r, while the value of the current flowing through the motor winding L decreases, the voltage across the terminals of the current detection resistor R decreases,
When the voltage becomes lower than the reference voltage Vo, the pulse width control circuit W
C turns on the transistor Tr. Note that the pulse width control circuit WC is configured by a CR circuit and determines the off time of the transistor Tr. Receiving motor 4
When controlling a two-phase stepping motor as d, such a constant current chopper circuit is required for the windings L corresponding to each of the A phase, the A inversion phase, the B phase, and the B inversion phase.

When this driving circuit is used, the current value I of the series circuit of the winding L of the receiving motor 4d and the current detecting resistor R is
FIG. 4 shows an example of changes in d and the voltage value Vd. The power supply voltage Vcc or 0 V is intermittently applied by turning on and off the transistor Tr. At this time, a substantially constant current is supplied to the winding L. In this constant current drive circuit, since the central processing unit 1 supplies the reference voltage Vo, the central processing unit 1 can control the transport speed and also control the reference voltage Vo. Can be controlled.

In a facsimile apparatus in which the transport speed changes when a document is transported and read,
Similarly to the above case, the drive torque can be controlled by controlling the drive current supplied to the stepping motor as the transmission motor 3c based on the transfer speed and the transfer state by the load. Next, a facsimile apparatus to which the present invention described in claim 3 is applied will be described. FIG. 5 is a timing chart showing changes in the supply current to each winding of the motor in comparison with the conventional method.
(A) shows the case of the conventional 1-2 excitation method, and (b)
Shows the case of the excitation method according to the present invention. In each case, the horizontal axis indicates time, and the vertical axis indicates the value of the drive current.

Both (a) and (b) show the situation when applied to a two-phase stepping motor.
4 shows supply currents for four windings of A phase, B phase, A inversion phase, and B inversion phase. In the case of the 1-2-phase excitation method, the drive current is supplied sequentially so that the supply periods of the drive current overlap by １ ／ as shown in the figure. Therefore, the one-phase excitation period in which the drive current is supplied simultaneously to one winding and the two-phase excitation period in which the drive current is simultaneously supplied to two windings appear alternately. I have.

In the conventional excitation method shown in (a), the current supplied to each winding is constant and does not change, but in the excitation method according to the present invention shown in (b), the drive current value during one-phase excitation is obtained. However, it is larger than the drive current value of the two-phase excitation. FIG. 6 shows the relationship between the excitation method and the rotation distance of the motor when the stepping motor is driven by these excitation methods. (A) in the figure shows the case of the conventional 1-2 excitation system, and (b) in the figure shows the case of the excitation system according to the present invention. In the case of the conventional 1-2 excitation method, the holding force of the stepping motor during one-phase excitation is smaller than that during two-phase excitation. For this reason, as shown in (a), the rotation distance at the time of two-phase excitation is different from the rotation distance at the time of one-phase excitation, and rotation unevenness occurs.

However, when the excitation method according to the present invention is used, the supply current at the time of one-phase excitation is made larger than the supply current at the time of two-phase excitation, so that the holding force of the stepping motor is reduced during the one-phase excitation. It can be made substantially constant at the time of two-phase excitation. For this reason, the rotation distance of the stepping motor is substantially constant between the one-phase excitation and the two-phase excitation,
The rotation unevenness is reduced, and the vibration is reduced.

[0027]

According to the first aspect of the present invention, a facsimile apparatus according to the present invention is provided based on the conveyance state of a document or a recording sheet.
By controlling the driving torque of the stepping motor, the driving torque at the time of reading an original or at the time of recording on recording paper is reduced, and the heat generation and noise of the motor are reduced.
That is, it is possible to provide a facsimile apparatus in which the stepping motor generates less heat and has low noise.

In the facsimile apparatus according to the second aspect of the present invention, the driving current of the stepping motor is changed based on the conveyance state of the original or the recording paper. Alternatively, the driving torque at the time of recording on the recording paper can be reduced. Therefore, it is possible to provide a facsimile apparatus in which the stepping motor generates less heat and has low noise.

In the facsimile apparatus according to the third aspect of the present invention, when controlling the drive of the stepping motor by the 1-2-phase excitation method, the drive current at the time of one-phase excitation is smaller than the drive current at the time of two-phase excitation. Control to increase. For this reason, the holding force of the stepping motor can be made substantially constant, and the occurrence of uneven feeding and vibration can be prevented as compared with the case of constant current driving.

Therefore, it is possible to provide a facsimile apparatus in which the interval between scanning lines at the time of reading or recording is prevented from being varied and the image quality is improved.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a configuration example of a facsimile apparatus according to the present invention.

FIG. 2 is a diagram illustrating an example of a conveyance path of a document and a recording sheet in a facsimile apparatus to which the present invention is applied.

FIG. 3 is a diagram illustrating a configuration example of a main part of the motor driver illustrated in FIG. 1;

FIG. 4 is a diagram illustrating an example of a change in a current value and a voltage value of a winding of a stepping motor.

FIG. 5 is a timing chart showing a change in a supply current to each winding of the motor in comparison with a conventional method.

FIG. 6 is a diagram showing a relationship between an excitation method and a rotation distance of a motor in comparison with a conventional method.

FIG. 7 is a diagram illustrating a relationship between a rotation speed and a driving torque when a stepping motor is driven at a constant current.

FIG. 8 is a diagram illustrating a relationship between a transport speed, a load, and a driving torque according to an operation.

[Explanation of symbols]

 10 facsimile machine 3c, 4d stepping motor Id driving current

Claims (3)

[Claims] When reading an original or recording image data,
A facsimile apparatus for transporting a document or recording paper using a stepping motor, wherein the driving torque of the stepping motor is controlled based on the transport state of the document or recording paper. 2. A motor control circuit according to claim 1, wherein said motor control circuit for supplying a drive current to said stepping motor changes the drive current of said stepping motor based on the conveyance state of a document or a recording sheet. Facsimile machine. 3. A facsimile apparatus which drives a stepping motor by a 1-2-phase excitation method and conveys a document or a recording sheet, wherein a driving current in one-phase excitation is larger than a driving current in two-phase excitation. A facsimile machine characterized by performing control as follows.