JP2002337413A - Method of controlling shuttle of printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent step out of a printer without interrupting printing when change of a temperature or a temporary fluctuation of a load occurs, to return a stepping motor to be in an angular speed pattern in a normal printing operation after a stable operation of the stepping motor, and to prevent deterioration in the printing quality when change of a temperature or a temporary fluctuation of a load occurs in a printer having a clank type shuttle mechanism consisting of the stepping motor. SOLUTION: The rotation speed of the stepping motor is switched to a speed capable of the self starting operation when change of a temperature or a temporary fluctuation of a load occurs. After the speed is switched to the speed capable of the self starting operation, dedicated print timing data is used during the printing. In addition, after the speed is switched thereto, the speed is returned to the angular speed pattern of the stepping motor at the printing operation when a predetermined time period has passed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus having a crank type shuttle mechanism comprising a stepping motor.

[0002]

2. Description of the Related Art A shuttle mechanism section of a printing apparatus having a crank type shuttle mechanism composed of a stepping motor and reciprocating a hammer bank having a plurality of printing elements (dot printing hammer etc.) by the shuttle mechanism. Will be described with reference to FIGS. 4 and 5.

A hammer bank 10 having a plurality of dot printing hammers (not shown) is supported on a guide shaft 12 via a direct-acting bearing 11. One end of each of the pair of cranks 13 is connected to a hammer bank 10 and a counter balancer 14, respectively, and the other end is connected to a stepping motor 20, which is a power source for reciprocating motion. Since these two cranks 13 are connected to the stepping motor 20 with a phase shift of 180 °, the hammerbank 10 and the counter balancer 14 reciprocate in opposite phases.

[0004] The rotation of the stepping motor 20 is controlled to operate on a predetermined angular velocity curve. The control is performed by a shuttle control circuit 30 that changes the drive cycle of the drive current supplied to the stepping motor 20,
This is performed by a shuttle drive circuit 40 that supplies a current to the stepping motor 20.

[0005] The printing paper is mounted facing the hammerbank 10, and is conveyed by paper feeding means (not shown). Then, in the course of the reciprocating operation of the hammer bank 10, printing is performed by driving the printing element toward the printing paper via an ink ribbon (not shown).

Next, examples of the angular velocity of the stepping motor 20 and the velocity waveform of the hammerbank 10 are shown in FIG. When the stepping motor 20 operates on a predetermined angular velocity curve, the hammer bank 10 connected by the crank 13 reciprocates in the velocity curve as shown in the drawing, and printing is performed in the course of the reciprocating operation. .

Further, in the shuttle mechanism, a sensor 35 for detecting the phase angle of the rotor of the stepping motor in order to prevent a step out due to a temperature change or a temporary load change.
In addition, a configuration is known in which an excitation phase of the stator is read, and an arithmetic unit for calculating the phase difference between the rotor and the stator is provided, and the stepping motor 20 is feedback-controlled by a closed loop. According to this configuration, when the angle difference between the phase angle of the rotor and the stator of the stepping motor is out of the predetermined range due to a temperature change or a temporary load change, the driving cycle of the driving current supplied to the stepping motor is changed. This makes it possible to correct the angle difference between the phase angle of the rotor and the stator and to prevent loss of synchronism.

[0008]

However, the above-described crank type shuttle mechanism in which feedback control is performed based on the phase difference between the rotor and the stator of the stepping motor has the following problems.

FIG. 6 shows an example of an angular velocity of a conventional stepping motor and a velocity waveform of a hammer bank.

When the phase difference between the phase angle of the rotor and the stator deviates from a predetermined range and the driving cycle of the driving current supplied to the stepping motor is changed, the phase angle of the rotor and the stator can be changed within a predetermined time. If the angular difference does not recover within the predetermined range and the angular velocity pattern of the stepping motor during normal printing operation cannot be restored, the printing must be interrupted and the stepping motor must be stopped. The reason for this is that if the power is not restored within a predetermined time, the same excitation phase will be energized for a long time, resulting in damage to the stepping motor or the drive element. The above-mentioned state in which the system does not return within the predetermined time is noticeable in a system having a large inertial force.

Further, even in a system in which feedback control is performed due to the phase difference between the rotor and the stator of the stepping motor, the step-out cannot be prevented, and the reliability of the device is reduced. .

Further, when the angle difference between the phase angle of the rotor and the phase angle of the stator does not return within a predetermined time, the stepping motor is temporarily stopped, restarted, and printing is restarted. .

On the other hand, in order to prevent a step-out due to a temperature change or a temporary load change, a stepping motor having a sufficiently large generated torque may be used. Cost was up.

Accordingly, the present invention provides a printing apparatus having a crank type shuttle mechanism including a stepping motor, which prevents loss of synchronism without interrupting printing when a temperature change or a temporary load change occurs. It is an object of the present invention to return to the angular velocity pattern of the stepping motor during the normal printing operation after the stable operation. Also,
An object of the present invention is to prevent a decrease in print quality when a temperature change or a temporary load change occurs.

[0015]

According to the present invention, there is provided a crank type shuttle comprising a hammer bank on which a plurality of printing elements are mounted and a stepping motor for reciprocating the hammer bank. A printing device having a mechanism for detecting a phase angle of a rotor of the stepping motor, and a calculation unit for reading an excitation phase of the stator and calculating an angle difference between the phase angle of the rotor and the stator; In the above, when the angle difference between the phase angle of the rotor of the stepping motor and the phase angle of the stator is out of a predetermined range, the rotation speed of the stepping motor is switched to a speed at which self-starting operation is possible.

According to another aspect of the present invention, there is provided a crank type shuttle mechanism including a hammer bank on which a plurality of printing elements are mounted, and a stepping motor for reciprocating the hammer bank. A sensor for detecting the phase angle of the rotor of the stepping motor, and a calculation unit for reading the excitation phase of the stator and calculating the angle difference between the phase angle of the rotor and the stator, and the phase of the rotor and the stator. When the angle difference between the angles is out of a predetermined range, in a printing apparatus that performs control for changing the drive cycle of the stepping motor drive current, the stepper motor is fixed to the rotor of the stepper motor within a predetermined time after the drive cycle is changed. When the angle difference between the phase angles of the slaves does not return within the predetermined range, the rotation speed of the stepping motor is switched to a speed at which the self-starting operation is possible.

Here, in the above control, it is preferable to control so that the printing is continued even after the rotation speed of the stepping motor is switched to a speed at which the self-starting operation is possible. In addition, it is preferable that dedicated print timing data be provided at the time of printing after switching to a speed at which activation can be performed.

In the above control, when the rotation speed of the stepping motor is switched to a speed at which the self-starting operation can be performed, after the stepping motor is stabilized, control is performed so as to return to the angular velocity pattern of the stepping motor during normal printing operation. Good to do.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the shuttle mechanism is the same as that of the prior art, and a description thereof will be omitted.

FIG. 1 shows a flow chart of feedback control of a stepping motor according to the present invention. FIG. 2 shows an example of an angular velocity of a stepping motor and a velocity waveform of a hammerbank according to the present invention, and an example of an angular velocity and a velocity waveform of a hammerbank of a conventional stepping motor.

First, an example of feedback control according to the present invention will be described with reference to FIG.

Here, when the phase excitation of the stepping motor is switched, the angle difference between the phase angle of the rotor and the stator in the step is calculated. The control for changing the driving cycle of the driving current to be performed is performed. This control is a prior art.

In the present invention, after the control for changing the driving cycle of the stepping motor is performed, a predetermined time, for example, 5
If the angle difference between the phase angle of the rotor and the stator does not return within a predetermined range within, for example, ± 90 °, the speed is switched to a speed at which self-starting operation is possible, for example, 100 rpm. In this case, it is preferable that the angular velocity is measured by a sensor attached to the rotor, and the switching be performed in a state where the rotation speed of the stepping motor is close to the switching speed. During this time, printing continues.

When the speed is switched to a speed at which self-starting operation is possible,
Since the speed waveform is different from the speed waveform of the hammer bank during the normal printing operation, if printing is continued at the same timing as during the normal printing operation, there is a possibility that the print quality may be degraded. In the present invention, when switching to a speed at which self-starting operation is possible, dedicated print timing data is used to prevent a decrease in print quality.

Further, after the stepping motor operates stably,
For example, the angular velocity pattern of the stepping motor during the normal printing operation is restored based on the elapsed time from when the switching to the speed at which the self-starting operation is possible is performed. As the elapsed time, for example, 100 ms is set. In this case, it is general to perform an acceleration operation and return.

FIG. 2 shows an example of the angular velocity of the stepping motor and the velocity waveform of the hammerbank in the embodiment of the present invention.

As shown in the figure, when the present invention is carried out, the stepping motor is prevented from stepping out without interrupting the printing when a temperature change or a temporary load change occurs, and the angular velocity pattern of the stepping motor during the normal printing operation in a short time. Can be restored.

In FIGS. 1 and 2, when the angle difference between the phase angle of the rotor and the stator of the stepping motor is out of the predetermined range, the feedback control for changing the driving cycle of the driving current supplied to the stepping motor is performed. Although the embodiment has been described, the feedback control for changing the drive cycle of the drive current is not performed when the angle difference between the phase angles is out of the predetermined range. Good.

[0029]

In a printing apparatus having a crank type shuttle mechanism composed of a stepping motor, the control method according to the present invention is implemented to prevent a reduction in printing speed and a reduction in printing quality without increasing costs. In addition, it is possible to prevent step-out when a temperature change or a temporary load change occurs, to return to the angular velocity pattern of the stepping motor at the time of normal printing in a short time without interrupting printing.

[Brief description of the drawings]

FIG. 1 is a flowchart of feedback control of a stepping motor according to the present invention.

FIG. 2 is a conceptual diagram showing an example of an angular velocity of a stepping motor and a velocity waveform of a hammer bank when the present invention is implemented.

FIG. 3 is a conceptual diagram showing a stepping motor angular velocity and a hammerbank velocity waveform.

FIG. 4 is a schematic side view showing an example of a crank type shuttle mechanism using a stepping motor.

FIG. 5 is a schematic top view of FIG.

FIG. 6 is a conceptual diagram illustrating an example of an angular velocity of a conventional stepping motor and a velocity waveform of a hammer bank.

[Explanation of symbols]

10 is a hammer bank, 11 is a linear bearing, 12 is a guide shaft, 13 is a crank, 14 is a counter balancer,
20 is a stepping motor, 30 is a shuttle control circuit,
35 is a position detection sensor, and 40 is a shuttle drive circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C480 CA01 CA16 CA44 CA45 CA57 CB03 EA01 EA17 EA27 EA29 5H580 AA05 BB06 CA10 FA04 FB03 FD03 FD12 JJ02

Claims (5)

[Claims] 1. A crank type shuttle mechanism comprising a hammer bank on which a plurality of printing elements are mounted, and a stepping motor for reciprocating the hammer bank,
A printing apparatus comprising: a sensor that detects a phase angle of a rotor of the stepping motor; and a calculation unit that reads an excitation phase of a stator and calculates an angle difference between the phase angle of the rotor and the stator. A step of switching the rotation speed of the stepping motor to a speed at which the self-starting operation can be performed when an angle difference between the phase angle of the rotor and the stator is out of a predetermined range. 2. A stepping motor for reciprocating a hammer bank having a plurality of printing elements, and a crank type shuttle mechanism including a stepping motor for detecting a phase angle of a rotor of the stepping motor. And a calculation unit for reading the excitation phase of the stator and calculating the angle difference between the phase angle of the rotor and the stator, when the angle difference between the phase angle of the rotor and the stator is out of a predetermined range. In a printing apparatus implementing control for changing the drive cycle of the stepping motor drive current, the angle difference between the phase angle of the rotor and the stator of the stepping motor falls within a predetermined range within a predetermined time after the drive cycle is changed. A shuttle control method for a printing apparatus, wherein, if not returning, the rotation speed of the stepping motor is switched to a speed at which self-starting operation is possible. 3. The shuttle control method for a printing apparatus according to claim 1, wherein the printing is continued even after the rotation speed of the stepping motor is switched to a speed at which self-starting operation is possible. Control method for a printing device. 4. A shuttle control method for a printing apparatus according to claim 3, wherein the printing apparatus further comprises dedicated print timing data at the time of printing after switching to the speed at which the self-starting operation is possible. Shuttle control method. 5. A shuttle control method for a printing apparatus according to claim 1, wherein when the rotation speed of the stepping motor is switched to a speed at which the self-starting operation is possible, normal printing is performed after the stepping motor is stably operated. A shuttle control method for a printing apparatus, wherein the method returns to an angular velocity pattern of a stepping motor during operation.