JP2002366001A - Controller and controlling method for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always excellently form an image by using an inexpensive PM type stepping motor and rotating the motor without causing step out even in the short starting time in an electrophotographic image forming device. SOLUTION: This image forming device is equipped with an exciting current switching means 102 switching the exciting current of the stepping motor 103 to a plurality of stages. In the case of starting the motor 103 first after turning on the power source of the image forming device or after cutting off the exciting current of the motor 103 due to any event, initializing operation to rotate the motor 103 in the phase signal of at least one or more patterns of repeated exciting patterns with frequency in a self-starting area is performed by a control means 101. For example, at starting paper feeding operation, the phase of the motor 103 and the phase of the phase signal are made coincident with each other and the operation is shifted to paper feeding operation immediately after the initializing operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device and a control method for an image forming apparatus such as a copying machine or a printer of an electrostatic recording system or an electrophotographic recording system using a stepping motor.

[0002]

2. Description of the Related Art Conventionally, for example, in an electrophotographic image forming apparatus, a DC brushless motor is used as a drive source for conveying paper such as recording paper, and each drive unit is driven from this motor via a gear or an electromagnetic clutch. , And the sequence operation is realized by turning on (ON) and off (OFF) the electromagnetic clutch.

Further, in recent high-speed machines having a large number of print outputs per unit time, a stepping motor is used to accurately control the operation of transporting the recording paper instead of turning on and off the drive by an electromagnetic clutch. In general, a configuration for improving the stability of paper conveyance has been becoming popular. In order to realize such high-speed sheet conveyance, a high-speed and high-torque motor is required, and a hybrid type stepping motor is used.

FIG. 5 shows a drive pulse at the time of starting the motor, and shows a relationship among a motor clock frequency, a motor clock pulse output, and the number of accumulated pulses.

[0005]

Recently, high-efficiency motors have been developed even for inexpensive PM-type stepping motors, but in any of these systems, the stepping motor normally rotates. In this case, the phase of the driving state of the phase excitation must coincide with the actual phase of the motor. Generally, in the non-excited state, there is no guarantee that they match, and when excited, the magnetic force of the excitation and the magnetic force of the rotor attract each other, but the phase of the phase excitation pattern is further rotated by one turn. Thus, for the first time, both phases can be completely matched.

For example, a two-phase stepping motor is
Considering the case of using two-phase excitation, the excitation pattern is 1
In order to rotate, it must be rotated with a clock pulse of at least eight clocks or more.

However, as shown in FIG. 5, when the PM type stepping motor is started up at the target speed in a short time, the frequency exceeds the self-starting region frequency earlier than when the necessary eight clocks are driven.

Further, as compared with the HB (hybrid) type, since the step angle is large and the output torque is small, the number of driving pulses with respect to the starting time is relatively small. Even when the HB type is activated in the same manner, the drive pulses for eight clocks can be sufficiently driven within the self-activation area.

As described above, in the conventional example, in order to rotate at a high speed by using an inexpensive PM type stepping motor, a sufficient margin must be provided for the starting time of the motor or the pull-out torque. It is a bottleneck in realizing transport.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is possible to use a low-cost PM type stepping motor to rotate a motor without step-out even in a short start-up time. It is an object of the present invention to provide a control device and a control method of an image forming apparatus capable of forming an image.

[0011]

A control device and a control method for an image forming apparatus according to the present invention are configured as follows.

(1) A control device for an image forming apparatus using a stepping motor as at least one of the driving sources, comprising: an exciting current switching means for switching an exciting current of the stepping motor in a plurality of stages. With the operation, the stepping motor is excited before the first stepping motor is driven from a state where the excitation of the stepping motor is turned off, and at least one set or more is set at a frequency within a self-starting range of the stepping motor. After the initialization operation for rotating the stepping motor with the drive pulse corresponding to the phase excitation pattern is performed, the stepping motor is driven.

(2) In the above (1), the stepping motor is stopped during the operation of the image forming apparatus, and an exciting current enough to satisfy at least a necessary holding torque is maintained.

(3) In the above (1) or (2),
When the continuous stop time of the stepping motor stopped during operation of the image forming apparatus is longer than a predetermined value, the excitation to the stepping motor is turned off, and the initialization operation is performed when the stepping motor is operated again. I made it.

(4) A method of controlling an image forming apparatus using a stepping motor as at least one of the driving sources, wherein the stepping motor is initially turned off in accordance with the operation of the image forming apparatus. Initialization to excite the stepping motor prior to driving the stepping motor and to rotate the stepping motor with a drive pulse for at least one set of phase excitation patterns at a frequency within the self-starting range of the stepping motor. After performing the operation, the stepping motor is driven.

(5) In the above (4), the stepping motor is stopped during the operation of the image forming apparatus, and the exciting current sufficient to at least satisfy the required holding torque is maintained.

(6) In the above (4) or (5),
When the continuous stop time of the stepping motor stopped during operation of the image forming apparatus is longer than a predetermined value, the excitation to the stepping motor is turned off, and the initialization operation is performed when the stepping motor is operated again. I made it.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a sectional view showing the overall configuration of an image forming apparatus according to the present invention, and shows a schematic configuration of an electrophotographic full-color printer.

In FIG. 1, reference numeral 1 denotes a printer main body;
2d is a photosensitive drum of four colors, 3a to 3d are exposure chargers,
a to 4d are cleaners, 5a to 5d are laser scanning units, 6a to 6d are transfer blades, 7a to 7d are developing units, 8a to 8d are developing units, 9 is an intermediate transfer belt, 1
Rollers supporting the intermediate transfer belt 9;
Is a cleaner.

Reference numeral 13 denotes a manual tray in which recording paper S is stored;
14 and 15 are pickup rollers thereof; 16 is a registration roller; 17 is a paper feed cassette containing recording paper S;
9 is a pickup roller, 20 is a vertical pass roller, 2
1 is a rotary roller, 22 is a secondary transfer roller, 23 is a fixing roller, 24 is an inner discharge roller, 25 is a discharge roller, 26 is a discharge tray, and 27 is a sensor for detecting paper (recording paper S). .

In the color printer having the above-described structure, an electrostatic latent image is formed on each of the photosensitive drums 2a to 2d by a laser scanning unit 5a to 5d using a semiconductor laser as a light source. Each developing unit 8a
To 8d. Then, this photosensitive drum 2a
The toner image of each color developed on the secondary transfer roller 2 is transferred to the secondary transfer roller 2 by an intermediate transfer means such as an intermediate transfer belt 9.
In two copies, four colors are collectively transferred to the recording paper, and the fixing roller 2
3. The toner is welded through a thermal fixing device including the inner paper discharge roller 24 to form a permanent image.

On the other hand, the recording paper is fed from a paper feed cassette 17 or a manual feed tray 13 or the like, and is conveyed to a secondary transfer roller 22 with registration timing by a registration roller 16. At this time, the paper transport units such as the pickup rollers 18 and 19 for feeding paper from the paper feed cassette 17, the vertical path roller 20, the registration roller 16, and the pickup rollers 14 and 15 for feeding paper from the manual feed tray 13 are operated at high speed. In order to realize a stable transport operation, each is driven by an independent stepping motor.

FIG. 2 is a block diagram showing a circuit configuration of a control system of the stepping motor. In the figure, reference numeral 101 denotes a control unit for controlling each unit, and 102 denotes an excitation current switching unit for switching the excitation current of the stepping motor 103 in at least two or more stages.

The control means 101 excites the stepping motor 103 prior to first driving the stepping motor 103 from the state where the excitation of the stepping motor 103 is turned off in accordance with the operation of the printer. The stepping motor 103 is driven after an initialization operation for rotating the stepping motor 103 with a drive pulse for at least one or more sets of phase excitation patterns at a frequency within the self-starting region of the step 103.

The control means 101 stops the stepping motor 103 during the operation of the printer,
At least an exciting current that satisfies the required holding torque is maintained. Further, when the continuous stop time of the stepping motor 103 stopped during operation of the printer becomes longer than a predetermined value, the excitation to the stepping motor 103 is cut off, and the initialization operation is performed when the stepping motor 103 is operated again. Is controlled to be performed.

FIG. 3 is a timing chart showing the operation of the embodiment of the present invention, and shows the initialization processing of the stepping motor when the paper feeding operation is started when the main power of the printer is turned on or when the printer is in a standby state. .

FIG. 3 shows the relationship among the target speed, the self-starting frequency, the motor clock frequency, the motor clock pulse output, the exciting current, and the number of accumulated pulses.

After the excitation current of the motor is turned off, the motor is driven at 100% excitation and a sufficient hold time is set, and then the motor is driven at a frequency within a self-starting range in which the motor can be sufficiently started. In this embodiment, since the two-phase stepping motor is used for 1-2-phase excitation, in order to make one round of the excitation pattern, an initialization operation of driving with a clock pulse of at least eight clocks or more is performed. To start the paper feeding operation.

FIG. 4 is a diagram showing a case where such an initialization operation of the present embodiment is performed during a sequence operation of an actual printer, and shows a relationship between an excitation current and a motor drive pulse.

In the period A of FIG. 4, after the copy operation is started, the motor is not excited until the first operation of the motor, and the phase state is uncertain. After performing the operation, the motor is continuously rotated, and after the required number of pulses, the motor is stopped and the excitation current is reduced to 30% and held.

In the period B of FIG. 4, the phase state of the motor is maintained while the excitation is down in the state A. When the next sheet feeding operation is started, the excitation is also increased to 100%, the motor is rotated, and then stopped and the excitation is kept down as described above.

In the period C in FIG. 4 as well, the motor rotates in the same manner. However, at this time, since the time until the next sheet feeding operation is long, the motor stops after the rotation is stopped and the exciting current is turned off.

Subsequently, in the period of D in FIG. 4, which is the next sheet feeding operation, the phase state is indefinite because the excitation of the motor is temporarily stopped. Therefore, as in the case of A in FIG. 4, the sheet feeding operation is started after the above-described motor initialization operation is performed.

In the period of E in FIG. 4, since the time until the next sheet feeding operation is long, after the rotation of the motor is stopped, the operation is stopped with the exciting current turned off.

By controlling in this manner, the motor can be rotated using an inexpensive PM type stepping motor even with a short start-up time without step-out.

That is, in this embodiment, in the first motor start-up after the printer power is turned on or after the motor excitation current is cut off by some event, the excitation pattern having the frequency within the self-start area is repeated. By performing an initialization operation for rotating the motor with at least one phase signal or more, for example, at the start of the paper conveyance operation, the phase of the motor and the phase of the phase signal are matched, and immediately after the initialization operation, the operation is shifted to the paper feeding operation. The motor can be rotated without step-out even with a short startup time.

In the standby mode, the exciting current is turned off and the power consumption is suppressed, and the motor is initialized at the start of the printing operation, so that stable paper conveyance can be realized.

The present invention is not limited to paper conveyance, and can be applied to, for example, a stepping motor for driving a fixing device, a stepping motor for driving a developing device, and the like. And other types of stepping motors.

[0040]

As described above, according to the present invention, an inexpensive PM type stepping motor can be used to rotate a motor even with a short start-up time without step-out.

Also, during the operation of the apparatus, during the period when the motor operation is not required or during standby, the excitation current is turned off to reduce the power consumption, and at the same time, the motor is initialized and the motor is rotated to perform a stable image forming operation. Can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a motor control system according to the embodiment;

FIG. 3 is a timing chart showing the operation of the embodiment.

FIG. 4 is an explanatory diagram showing an initialization operation of the embodiment.

FIG. 5 is an explanatory diagram showing a drive pulse when the motor is started.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer main body 2a-2d Photosensitive drum 5a-5d Laser scanning unit 8a-8d Developing device 9 Intermediate transfer belt 13 Manual feed tray 14 Pickup roller 15 Pickup roller 16 Registration roller 17 Paper feed cassette 18 Pickup roller 19 Pickup roller 20 Vertical path roller 23 Fixing roller DESCRIPTION OF SYMBOLS 101 Control means 102 Excitation current switching means 103 Stepping motor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C058 AB17 AD01 AE02 AE04 AF15 AF31 GE03 GE08 GE13 2H027 DA01 DA16 DA40 DA41 EA15 EC06 EC09 EE01 EE02 EE03 EE04 EF01 EF12 EF15 EG02 EG04 EJ17 ZA01 5H580 BB05 BB05 BB05 BB05 BB05 BB05 BB05 BB05

Claims (6)

[Claims] 1. A control device for an image forming apparatus using a stepping motor as at least one of a driving source, comprising: an exciting current switching means for switching an exciting current of the stepping motor in a plurality of stages; With the step, the stepping motor is excited before the stepping motor is first driven from the state where the excitation of the stepping motor is turned off, and at least one set or more is set at a frequency within a self-starting range of the stepping motor. A control device for an image forming apparatus, comprising: performing an initialization operation for rotating the stepping motor with a drive pulse corresponding to a phase excitation pattern, and then driving the stepping motor. 2. The image forming apparatus according to claim 1, wherein the stepping motor is stopped during the operation of the image forming apparatus, and an exciting current sufficient to satisfy at least a required holding torque is maintained. Control device. 3. If the continuous stopping time of the stepping motor stopped during operation of the image forming apparatus is longer than a predetermined value, the excitation to the stepping motor is turned off, and the stepping motor is initialized when the stepping motor is operated again. The control device for an image forming apparatus according to claim 1, wherein the control device performs an image forming operation. 4. A method for controlling an image forming apparatus using a stepping motor as at least one of a driving source, wherein the stepping motor is first turned off in a state where the excitation of the stepping motor is turned off with the operation of the image forming apparatus. An initialization operation of exciting the stepping motor before driving the stepping motor and rotating the stepping motor with a drive pulse of at least one set of phase excitation patterns at a frequency within a self-starting range of the stepping motor. A step of driving the stepping motor after performing the step (a). 5. The image forming apparatus according to claim 4, wherein the stepping motor is stopped during operation of the image forming apparatus, and a state is maintained in which an exciting current sufficient to satisfy at least a necessary holding torque is maintained. A method for controlling an image forming apparatus. 6. When the continuous stopping time of the stepping motor stopped during the operation of the image forming apparatus is longer than a predetermined value, the excitation to the stepping motor is cut off, and when the stepping motor is operated again, an initial state is set. 6. The image processing device according to claim 4, wherein a morphing operation is performed.
The control method of the image forming apparatus described in the above.