JP3295966B2 - Control method of paper feed motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a paper feed motor used in a printer.

[0002]

2. Description of the Related Art In recent years, in a serial printer, high-density graphic printing and printing of enlarged characters by a combination of plural times of scanning of a print head and paper feeding have been performed.
Paper feed accuracy is a factor that has a great influence on print quality. In other words, if the paper feed amount is larger than the appropriate value, white streaks are conspicuous, and if the paper feed amount is small, black streaks are prominent. Therefore, in the prior art, a high-resolution stepping motor is used to improve the paper feeding accuracy and prevent the occurrence of white streaks and black streaks. The width of the yoke plate, which is a component, is small, and it tends to be deformed by magnetic annealing to remove residual magnetism, and the resolution is naturally limited.

Therefore, in order to realize a higher resolution, the excitation state is alternately switched between a two-phase excitation state (s2) and a one-phase excitation state (s1) as shown in FIG. And a resolution twice as high as that of the step motor itself.

FIG. 6A shows a case where the motor stops in the one-phase excitation state, and FIG. 6B shows a case where the motor stops in the two-phase excitation state. It is excited and switched to the holding current value to stop.

[0005]

However, the above-mentioned prior art has the following problems.

When printing is performed in the one-phase excitation stop state shown in FIG. 6A, black streaks occur, and when printing is performed in the two-phase excitation stop state shown in FIG. 6B, white streaks occur.

The torque generated in the two-phase excitation state is 2
This is because the vector sum of the generated torques generated by the two drive coils becomes larger than the generated torque in the one-phase excitation state. That is, the generated torque of the one-phase excitation cannot reach the predetermined rotation angle during the final phase excitation time of the period Td from the last phase switching time point Tlast shown in FIG. 6, and therefore, Td may be increased. However, when the two-phase excitation is stopped, an extra energy key is input, and the motor itself generates heat.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a stable paper feed control method irrespective of the excitation state.

[0009]

In order to solve the above problems, a method of controlling a paper feed motor for feeding a stepping paper feed motor of a terminal printer having a paper feed train mechanism by one- or two-phase excitation drive is provided. When the stepping paper feed motor is stopped in the two-phase excitation state, the natural frequency including the stepping paper feed motor and the mechanical unit after exciting the final phase for a first time from the last phase switching time A current having a frequency different from that of the first time period, and a current smaller than the first time period is continuously supplied, and control is performed to switch to the stop current after a predetermined time period, and the stepping paper feed motor is stopped in the one-phase excitation state. The stepping paper feed motor and the mechanism after exciting the final phase for a second time longer than the first time from the last phase switching time. A current having a frequency different from the natural frequency, including, and is characterized by performing control for switching to the stop time of current after a predetermined continuous flow of current smaller than during the second time period. Also,
In a control method of a paper feed motor for feeding a stepping paper feed motor of a terminal printer having a paper feed train mechanism by a 1-2-phase excitation drive, when stopping the stepping paper feed motor in a two-phase excitation state, A first final phase excitation step of supplying an excitation current, which is a current to be supplied when the stepping paper feed motor is driven, to the excitation coil for a first time from the last phase switching time to excite the final phase;
When the stepping paper feed motor is stopped in the two-phase excitation state, a current to be supplied to the exciting coil when the stepping paper feed motor is stopped is set as a holding current after the lapse of the first time. A second step of alternately switching the supply current to the excitation coil between the excitation current and the holding current at a preset chopping frequency such that the natural frequency including the mechanism does not resonate with the frequency of the current of the excitation coil. When the stepping paper feed motor is stopped in the one chopping control process and the one-phase excitation state, the exciting current is supplied to the exciting coil for a second time longer than the first time from the time of the last phase switching. A second final phase exciting step of exciting the final phase by the stepping paper feed motor, and stopping the stepping paper feed motor in the one phase excited state. After a time, it is characterized in that and a second chopping control process for switching alternately supplying current to the exciting coil between said excitation current and the holding current in the chopping frequency. Further, in a paper feed motor control device for feeding paper by a 1-2 phase excitation drive of a stepping paper feed motor of a terminal printer having a paper feed train mechanism, the stepping paper feed motor is stopped in a two-phase excitation state. In this case, the current having a frequency different from the natural frequency including the stepping paper feed motor and the mechanism after exciting the final phase for a first time from the time of the final phase switching, and When a current smaller than that of the first time is continuously supplied, the current is switched to the stop current after a predetermined time, and the stepping paper feed motor is stopped in the one-phase excitation state, the first time is longer than the last phase change time. A current having a frequency different from the natural frequency including the stepping paper feed motor and the mechanism after exciting the final phase for the second time; And a control unit for outputting a current switching signal for switching to the stop current after a predetermined time by continuously flowing a current smaller than the second time, and driving the stepping paper feed motor based on the current switching signal. And a paper feed drive circuit for supplying current. Still further, in a paper feed motor control device for feeding a stepping motor of a terminal printer having a paper feed train mechanism by 1-2-phase excitation drive, a drive current is supplied to the stepping paper feed motor based on a current switching signal. And a control unit that generates and outputs the current switching signal, wherein the control unit includes:
When stopping the stepping paper feed motor in the two-phase excitation state, the current switching signal is supplied to the exciting coil as the driving current during the driving of the stepping paper feed motor for a first time from the last phase switching time. A first phase for supplying an exciting current which is a current to be excited to excite the final phase;
A current to be supplied to the exciting coil when the stepping paper feed motor is stopped when the stepping paper feed motor is stopped in the two-phase excitation state and after the first time has elapsed, as a final phase excitation signal. With respect to the exciting coil, the holding current is set between the exciting current and the holding current at a preset chopping frequency such that the natural frequency including the stepping motor and the mechanism does not resonate with the frequency of the current of the exciting coil. A first chopping control signal for alternately switching the supply current is used. When the stepping paper feed motor is stopped in the one-phase excitation state, a second time longer than the first time from the last phase switching time is used. A second final phase excitation signal for supplying the excitation current as the drive current to the excitation coil to excite the final phase, When the stepping paper feed motor is stopped in the one-phase excitation state and after the lapse of the second time, the supply current to the excitation coil alternates between the excitation current and the holding current at the chopping frequency. And a second chopping control signal for switching to the second chopping control signal.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic plan view of a mechanical portion of a terminal printer to which the present invention is applied.
Side frames 13, 14 are attached to both sides of the upper surface of the
The platen 3 is attached between the side frames 13 and 14. The platen 3 includes a paper feed motor 2
As a result, the platen 3 rotates through the intermediate platen wheel 5 and the platen gear 4 attached near the end of the platen 3 on the central axis.

In this apparatus, the platen gear 4, the intermediate gear 5, and the paper feed motor pinion 6 set the minimum resolution of the paper feed to 360 DPI (dots / inch) with respect to the paper on the outer peripheral surface of the platen 3. The speed reduction ratio of the configured paper feed gear train mechanism is set to a predetermined value. FIG. 2 is an enlarged view of the paper feed wheel train at the upper part of FIG. (However, the top, bottom, left, and right are switched from FIG. 1). FIG. 5 is a known circuit diagram for driving the device.
A to PD and the current switching signal terminal PH are electrically connected. When the motor is driven, the transistor Q5 is turned on by an input signal to PH, and the data terminals PA to PD of each phase are turned on.
On the basis of the phase data signal input from the control unit 1 at predetermined time intervals, each of the phase driving transistors Q1 to Q4 is turned on.
Turn off to energize the drive excitation coil. The control operation of the device configured as described above will be described below.

FIGS. 3A and 3B are operation diagrams when the paper feed motor of the printing apparatus according to the embodiment of the present invention is driven by a one- or two-phase excitation method. FIG. ) Indicates when the motor stops in the two-phase excitation state.

In FIG. 3A, when the final excitation phase of the deceleration control is a single-phase excitation state, the final phase switching time Tla
After exciting the final phase for T0 (e.g., 12 to 14 μs) from st, the exciting current is supplied to the exciting coils A to D of the paper feed motor 2 at a frequency of 2.8 to 3 kHz. The chopping control 7 that alternately repeats the holding current energizing state 9 for supplying the current is performed. The chopping control 7 generates a torque lower than the excitation current conduction state 8 and higher than the holding current conduction state.

The chopping frequency is set so that the natural frequency including the stepping motor and the mechanism does not coincide with the frequency of the current of the exciting coil to cause resonance.
This is set in advance.

The case of stopping in the two-phase excitation state of FIG. 3B is the same as that of FIG. 3A, but in the two-phase excitation state, the generated torque is larger than that of the one-phase excitation, After exciting the final phase for a short T4 (for example, 2 to 4 μs) shorter than Tlast at the time of one-phase excitation, exciting current is supplied to the exciting coils A to D of the paper feed motor 2 at a frequency of 2.8 to 3 kHz. A chopping control 7 is performed in which a current conduction state 8 and a holding current conduction state 9 for supplying a holding current are alternately repeated.

Here, the reason for performing the chopping control 7 in FIG. 3 will be described. In FIG. 3, when shifting from the deceleration control to the stop control, if the current in the excitation current conduction state 8 is continuously supplied to the paper feed motor 2 in the final excitation step, as shown in FIG.
Due to the inertia of the paper feed train mechanism and the effect of the large torque generated by the motor 2, the damping is longer than the stable position of the rotor (overshoot 10) and further attempts to return to the original position (undershoot 11). Then, the generated torque is weakened after a time T8 from the final phase switching point in FIG. 4 and further switched to a weaker holding generated torque after a time T9 when the rotor returns to the predetermined position, thereby quickly suppressing the damping and stopping at the predetermined position. Can be done. Further, since a large current is not supplied to the exciting coil for a long time, heat generation of the exciting coil can be reduced.

[0018]

As described above, according to the present invention, paper feed control finer than the resolution of the motor itself can be realized with high accuracy and with the minimum power consumption.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a mechanical portion of a terminal printer to which the present invention is applied.

FIG. 2 is an enlarged view of a paper feed train wheel.

FIG. 3 is an operation diagram illustrating an embodiment of the present invention.

FIG. 4 is a diagram illustrating behavior of a rotor of a paper feed motor.

FIG. 5 is a drive circuit diagram of a paper feed motor.

FIG. 6 is an operation diagram illustrating a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control part 2 Paper feed motor 3 Platen 4 Platen gear 5 Intermediate gear 6 Paper feed motor pinion 7 Chopping control 8 Excitation current conduction signal 9 Holding current conduction signal 10 Overshoot 11 Undershoot 12 Base frame 13, 14 Side frame

Claims (4)

(57) [Claims] 1. A method for controlling a paper feed motor for feeding a stepping paper feed motor of a terminal printer having a paper feed train mechanism by a 1-2-phase excitation drive, wherein the stepping paper feed motor is driven in a two-phase excitation state. Is stopped, the final phase is excited for a first time from the final phase switching time, and then the stepping paper feed motor and
Electric waves having a frequency different from the natural frequency including the mechanical part
There the flow, and performs a control to switch to the standstill current after a predetermined continuous flow of current smaller than during the first time period, when stopping the stepping paper feed motor in one-phase excitation state, final after exciting the first time longer than the second time during the final phase of a phase switching time point, further wherein Suteppi
Is the natural frequency including the paper feed motor and mechanism
A control method for controlling a paper feed motor , wherein a current having a different frequency and a current smaller than that during the second time are continuously supplied, and control is performed to switch to a stop current after a predetermined time. 2. A terminal pre-equipped with a paper feed train mechanism.
Stepping paper feed motor with 1-2 phase excitation drive
In the method for controlling a paper feed motor for feeding paper , the stepping paper feed motor is stopped in a two-phase excitation state.
During the first time from the last phase switching
Supplied to the coil when the stepping paper feed motor is driven
Excitation of the final phase by supplying the excitation current
Stopping the stepping paper feed motor in the first final phase excitation step and in the two-phase excitation state.
When stopping, after the lapse of the first time, the exciting coil
Should be supplied when the stepping paper feed motor stops.
Using the current as the holding current, the stepping motor and mechanism
And the natural frequency including the current frequency of the exciting coil
At the preset chopping frequency to prevent resonance
The excitation coil is connected between the excitation current and the holding current.
First chopping control for alternately switching the supply current to be applied
And stopping the stepping paper feed motor in the one-phase excitation state.
When that length than the first time than the final phase cut conversion e time
Supplying the exciting current to the exciting coil during a second time period.
A second final phase exciting step of exciting the final phase by stepping the stepping paper feed motor in the one phase excited state.
When stopping, after the lapse of the second time, the chopping
Between the excitation current and the holding current at the excitation frequency.
The second chode alternately switches the supply current to the magnetic coil
And controlling the paper feed motor. 3. A terminal pre-equipped with a paper feed train mechanism.
Stepping paper feed motor with 1-2 phase excitation drive
In the control device for a paper feed motor for feeding paper, the stepping paper feed motor is stopped in a two-phase excitation state.
The last phase switching time for the first time
After exciting the phase, the stepping paper feed motor and
Electric waves having a frequency different from the natural frequency including the mechanical part
Current and less current than at the first time
Switch to the stop current after a predetermined period of time
When stopping the stepping paper feed motor in the excited state
Is longer than the first time from the last phase switching time
After exciting the final phase for the second time, further stepping
Different from the natural frequency including the paper feed motor and mechanism
Current having a frequency of
When a current smaller than
Control unit that outputs a current switching signal for switching to current
And the stepping paper feed based on the current switching signal.
A paper feed motor control device, comprising: a paper feed drive circuit that supplies a drive current to the motor. 4. A terminal pre-equipped with a paper feed train mechanism.
Paper feed with 1-2 phase excitation drive
In the control device of the paper feed motor , the stepping paper feed motor is controlled based on the current switching signal.
A paper feed drive circuit that supplies a drive current to the motor, and a control unit that generates and outputs the current switching signal , wherein the control unit transmits the current switching signal in a two-phase excitation state in a two-phase excitation state.
When stopping the stepping paper feed motors, the final phase switching
During the first time from the switching time, the excitation coil is driven as described above.
The current is supplied when the stepping paper feed motor is driven.
Supply the exciting current, which is the current to be supplied, to excite the final phase.
And the stepping paper feed motor is stopped in the two-phase excitation state.
Stopping, and after the first time has elapsed, the excitation
Supplied to the coil when the stepping paper feed motor stops
The current to be held is the holding current, and the stepping motor and
The natural frequency including the mechanical part is the current oscillation of the exciting coil.
Chopping frequency preset so that it does not resonate with the power
The exciting coil between the exciting current and the holding current in numbers.
For alternately switching the supply current to the
As a chopping control signal, the stepping paper feed motor is stopped in the one-phase excitation state
At the time of the last phase switching,
During a long second time, the excitation coil
A second phase for supplying the exciting current to excite the final phase;
The stepping paper feed motor is stopped in the one-phase excitation state as the final phase excitation signal.
When stopping and after the lapse of the second time,
Between the exciting current and the holding current at the
The supply current to the exciting coil is alternately switched.
And a second chopping control signal for controlling the paper feed motor.