JP2002366002A - 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. 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 hold an exciting state by rotating 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.

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. 6 shows a driving 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. 6, when the target speed of the PM type stepping motor is increased 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. The initialization operation for rotating the stepping motor is performed by the driving pulse corresponding to the phase excitation pattern described above, and the excitation state is maintained until the operation of the stepping motor is completed.

(2) In the above (1), immediately after the main power supply of the image forming apparatus is turned on, an initialization operation of the stepping motor is performed, and the exciting current sufficient to satisfy at least the necessary holding torque is maintained. I did it.

(3) In the above (1), after the main power of the image forming apparatus is turned on, the stepping motor is not excited until the operation of the image forming apparatus is started. When the stepping motor is excited, the stepping motor is initialized, and after the operation of the image forming apparatus is stopped, the stepping motor is turned off.

(4) A method for controlling an image forming apparatus using a stepping motor as at least one of the driving sources, wherein the stepping motor is first turned off when 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. And the excited state is maintained until the operation of the stepping motor is completed.

(5) In the above (4), immediately after the main power of the image forming apparatus is turned on, an initialization operation of the stepping motor is performed, and the exciting current sufficient to satisfy at least the necessary holding torque is maintained. I did it.

(6) In the above (4), after the main power of the image forming apparatus is turned on, the stepping motor is not excited until the operation of the image forming apparatus is started. When the stepping motor is excited, the stepping motor is initialized, and after the operation of the image forming apparatus is stopped, the stepping motor is turned off.

[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. An initialization operation for rotating the stepping motor 103 with a drive pulse for at least one set or more of phase excitation patterns at a frequency within the self-starting region of 103 is performed, and the excitation state is maintained until the operation of the stepping motor is completed. To control.

The control means 101 performs an initializing operation of the stepping motor 103 immediately after the main power supply of the printer is turned on, so that an exciting current enough to satisfy at least a necessary holding torque is maintained. Further, after the main power of the printer is turned on, the stepping motor 103 is not excited until the operation of the printer is started.
When the operation of the printer is started, the stepping motor 103 is excited and the stepping motor 103 is initialized, and the excitation of the stepping motor 103 is controlled to be stopped after the operation of the printer is stopped.

FIG. 3 is a timing chart showing the operation of the embodiment of the present invention. The excitation current of the stepping motor is turned off when the main power of the printer is turned on, any door is opened or closed, or a jam is cleared. 14 shows the initialization process after (cut).

FIG. 3 shows the relationship among the excitation control signal, the motor clock, the currents of the coils A and B, and the motor clock frequency.

After the excitation current of the motor is turned off, the motor is driven to a 100% excitation state and a sufficient hold time is taken. 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, the motor is driven by clock pulses of at least eight clocks, and then the motor is stopped. Further, after a sufficient hold time is provided for damping the vibration of the motor due to the stop, the excitation current is reduced to 30%. A series of these operations is an initialization (coordination) operation of the motor.

(First Embodiment) FIG. 4 is a diagram showing a case where such an initialization operation of this embodiment is performed during a sequence operation of an actual printer. The state of the main power supply, the exciting current of the motor, The relationship between motor initialization, print operation, door open / jam processing, and the like is shown.

In the period A in FIG. 4, the motor is not excited immediately after the main power supply of the printer is turned on, and the phase state is uncertain. Hold down state.

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 printing operation is started, the excitation of the motor is also increased to 100%, and the paper feeding operation is started. When the printing operation is completed, the state shifts to the excitation down state again while maintaining the phase state.

The period C in FIG. 4 shows a case where the front door of the printer is opened due to jam processing or the like. When the front door is opened, the power to the motor and other driving parts is cut off (not shown) so that the user or serviceman does not touch the driving parts and cause injury. Excitation is also stopped. For this reason, the phase state becomes indefinite, and when the jam processing ends and the front door is closed again, the above-described motor initialization operation is performed.

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

(Second Embodiment) FIG. 5 is a diagram showing the operation of the second embodiment of the present invention, and the overall configuration of the apparatus and the initialization operation are the same as those of the first embodiment.

In the period A in FIG. 5, the motor is not initialized and is not excited when the main power of the printer is turned on.
The phase state remains indeterminate.

In the period B of FIG. 5, when the printing operation is started, the initialization operation of the motor is started. Then, after the initialization operation, the excitation current of the motor is temporarily reduced, the excitation current is increased again when starting the sheet feeding operation, and after a series of printing operations, the excitation current is turned off and stopped.

In the period C shown in FIG. 5, even if the door is opened due to jam processing or the like, the excitation is turned off before the door is opened, so that nothing is performed on the motor.

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.

In the standby mode, the excitation current is turned off and the power consumption is suppressed, and the motor is initialized at the same time as the printing operation is started, so that stable paper conveyance can be realized.

That is, in this embodiment, after the power supply of the printer is turned on or after the excitation current of the motor is cut off by some event, at least one phase pattern of the excitation pattern repeated at a frequency within the self-starting range is obtained. Performs an initialization operation that keeps the excitation state by rotating the motor.For example, at the start of the paper transport operation, the phase of the motor and the phase of the phase signal are made to match, so that even if the startup time is short, there is no step-out. , Can rotate the motor.

The present invention can be applied not only to paper conveyance but also 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.

[0043]

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.

In the standby mode, the excitation current is turned off and the power consumption is suppressed, and the motor is initialized at the same time as the printing operation is started, so that 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 according to the first embodiment;

FIG. 5 is an explanatory diagram showing an initialization operation of the second embodiment.

FIG. 6 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

Claims (6)

[Claims] 1. A control device for an image forming apparatus using a stepping motor as at least one of driving sources, 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 maintaining the excited state until the operation of the stepping motor is completed. 2. The apparatus according to claim 1, wherein an initialization operation of the stepping motor is performed immediately after the main power of the image forming apparatus is turned on, so that an exciting current sufficient to satisfy at least a required holding torque is maintained. Item 2. A control device for an image forming apparatus according to Item 1. 3. After the main power of the image forming apparatus is turned on, the stepping motor is not excited until the operation of the image forming apparatus is started. When the operation of the image forming apparatus is started, the stepping motor is excited. 2. The control device for an image forming apparatus according to claim 1, wherein an initialization operation is performed, and after the operation of the image forming apparatus is stopped, excitation of the stepping motor is stopped. 4. A method for controlling an image forming apparatus using a stepping motor as at least one of a drive 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 for at least one or more sets of phase excitation patterns at a frequency within the self-starting region of the stepping motor. And controlling the excitation of the stepping motor until the operation of the stepping motor is completed. 5. The apparatus according to claim 1, wherein the stepping motor is initialized immediately after the main power of the image forming apparatus is turned on, so as to maintain an exciting current sufficient to at least satisfy a required holding torque. The method for controlling an image forming apparatus according to claim 4, wherein 6. After the main power of the image forming apparatus is turned on, the stepping motor is not excited until the operation of the image forming apparatus is started. When the operation of the image forming apparatus is started, the stepping motor is excited. 5. The control method for an image forming apparatus according to claim 4, wherein the initialization operation is performed, and after the operation of the image forming apparatus is stopped, the excitation of the stepping motor is turned off.