JP3813793B2 - Driving method of stepping motor for conveyance - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for driving a conveyance stepping motor, and in particular, when recording a desired image separately for each line, the number of heating elements to be energized in each row is less than a predetermined number. The present invention relates to a method for driving a transporting stepping motor when performing so-called dynamic division recording.
[0002]
[Prior art]
Conventionally, stepping motors have characteristics such as the rotation angle and rotation speed of the motor being determined in proportion to the number of input pulses and the input pulse speed, extremely good start / stop characteristics, and high responsiveness and output. For this reason, it is used as a carriage motor that drives the carriage of a printer and a conveyance motor that conveys recording paper.
[0003]
A line printer will be described as an example in which such a stepping motor is used as a recording paper transporting stepping motor. A long platen roller is rotatably supported between a pair of side frames in the line printer. A line thermal head is supported on the printer main body by a support lever so as to be able to contact with and separate from the platen roller. A head pressure contact spring for pressure contact is attached to the back side of the line thermal head. The line thermal head has heating elements arranged in the longitudinal direction, and each heating element has an energization control unit for selectively controlling energization to each heating element based on recording data. Connected.
[0004]
On the other hand, a conveyance stepping motor is mounted on the printer body, and a conveyance roller is connected to the drive shaft of the conveyance stepping motor via a transmission gear group, and the recording paper is taken out from the loading tray. , And is supplied between the platen roller and the line thermal head. In addition, a conveyance control unit is connected to the conveyance stepping motor via a motor driver.
[0005]
Further, a supply roll for supplying an ink ribbon is disposed on the upstream side of the platen roller in the recording paper conveyance direction, and a take-up roll is disposed on the downstream side of the recording paper conveyance direction. The ink ribbon is supplied between the platen roller and the line thermal head by driving a winding bobbin that rotates the winding roll.
[0006]
When recording is performed by a line printer having such a configuration, first, the recording stepping motor is driven to rotate the conveyance roller to convey the recording paper one by one from the loading tray. Supply between the thermal head. When the recording paper is conveyed to the recording start position, the line thermal head is pressed against the platen roller via the recording paper and the ink ribbon, and the energization control unit selectively energizes each heating element based on the recording data, and the ink Melt and transfer the ribbon to the recording paper. When the recording of the first line is completed, the transporting stepping motor is driven, and the recording of the next second line is started based on the recording data. When the recording up to the final line is completed as described above, in the case of a color image, the conveyance roller is rotated in the reverse direction to temporarily return the recording paper to the recording start position, and the next second color is recorded. When recording is performed for each color of cyan, magenta, and black, recording of a full-color image is completed.
[0007]
Here, the energization control to each heating element of the line thermal head by the energization control unit will be described. Conventionally, when energizing each heating element, as shown in FIG. So-called dynamic division recording has been performed in which the number of heat generating elements to be energized in one line is controlled to be arbitrarily divided and energized so as to be a predetermined number or less.
[0008]
According to such dynamic division recording, the amount of electric power to be supplied at one time can be suppressed, and the number of energized heating elements necessary for recording for each line is used instead of dividing into a fixed number of divisions. Therefore, the recording speed was not too slow.
[0009]
[Problems to be solved by the invention]
However, in the conventional method of driving a stepping motor for conveyance, as shown in FIG. 8, even if the number of divisions is changed for each recording line and the motor speed is frequently changed when performing dynamic division recording, The magnitude of the current value passed through the transporting stepping motor remained the same and was not changed. For this reason, when there is no difference in the number of divisions between the current recording line and the previous recording line or when the number of divisions is small, an excessive current value is given beyond the originally required current value. The current consumption was uselessly large.
[0010]
For example, when the number of divisions of the previous recording line changes to 1 while the number of divisions of the current recording line changes to 1, the current value must be increased in order to increase the speed of the transporting stepping motor. When the number of divisions between the current recording line and the immediately preceding recording line is the same, there is no need to change the driving speed of the transporting stepping motor, and therefore it is not necessary to increase the applied current value. However, in the conventional method of driving a transporting stepping motor, a constant current value that is always set to a large value is always applied regardless of the difference between the current recording line and the immediately preceding recording line. When it is small, the current consumption is wasted.
[0011]
If energy is applied in this way, there is a problem that noise and vibration of the motor are generated.
[0012]
The present invention has been made in view of such problems, and can control the current value provided by the stepping motor for conveyance during dynamic division printing without waste, realizing reduction in motor noise and energy saving. It is an object of the present invention to provide a method for driving a transporting stepping motor.
[0013]
[Means for Solving the Problems]
The driving stepping motor driving method according to claim 1 of the present invention is characterized in that the difference absolute value of the number of divisions between the current recording line and the immediately preceding recording line is obtained, and when the difference absolute value is “0”, The current value applied to the transporting stepping motor is reduced, and the current value applied to the transporting stepping motor is controlled to increase as the absolute difference value increases. By adopting such a method, if there is no change in the absolute value of the number of divisions between the current recording line and the previous recording line, the motor is driven using the inertial force of the transporting stepping motor. By doing so, current can be more efficiently applied to the stepping motor for conveyance, and the current value to be actually applied is determined according to the magnitude of the difference absolute value of the number of divisions. The generation of noise and vibration can be prevented by suppressing useless energy application without excessively applying current to the stepping motor.
[0015]
The feature of the driving method of conveying stepping motor according to claim 2, Oite to claim 1, the current value to be applied based on the division number of the difference absolute value between the current recording line and the immediately preceding recording line The predetermined duty ratio is obtained and applied according to this. By adopting such a method, for example, when the difference absolute value of the number of divisions is large, it is possible to appropriately give a desired current value by increasing the duty ratio.
[0016]
Further, according to a third aspect of the present invention, there is provided a driving stepping motor driving method characterized in that, in the second aspect , when a predetermined current value is applied according to the duty ratio, the energization on time and the energization in advance for each difference absolute value of the division number The off time is set. By adopting such a method, a current value according to the absolute value of the difference in the number of divisions can be quickly and appropriately applied to the transporting stepping motor.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a method for driving a transporting stepping motor according to the present invention will be described below with reference to the drawings.
[0018]
The transport stepping motor driving method of the present invention obtains the absolute value of the difference between the number of divisions between the current recording line and the immediately preceding recording line, and the magnitude of the current value passed to the transport stepping motor in proportion to the absolute value of the difference. It has the feature in controlling to change the height. Here, the dynamic division recording refers to the number of heating elements to be energized necessary for recording for one line of each color, and the division energization is performed so that the number of heating elements to be energized at a time is equal to or less than a predetermined number. To record. The number of heating elements to be energized is obtained based on image recording data, for example.
[0019]
FIG. 1 shows an example of a line printer 1 that executes a method of driving a transporting stepping motor according to the present invention. The line printer 1 has a pair of side frames 3 and 3 attached to the side surface of the printer body 2, and a long platen roller 4 is rotatably supported between the side frames 3 and 3. Has been. A line thermal head 5 in which heating elements are arranged and arranged is supported on the printer main body 2 so as to be able to contact with and separate from the platen roller 4. The line thermal head 5 is provided with a plurality of head pressing springs 6 for applying a pressing force to the back side.
[0020]
The printer main body 2 is equipped with a transporting stepping motor 7, and a transporting roller (not shown) is connected to a drive shaft 7 a of the transporting stepping motor 7 via a transmission gear group 8. Recording paper (none of which is shown) is taken out from the loading tray and is supplied between the platen roller 4 and the line thermal head 5.
[0021]
Further, a supply roll (not shown) for supplying an ink ribbon is arranged on the upstream side of the platen roller 4 in the recording paper conveyance direction, and a winding roll (not shown) is arranged on the downstream side of the recording paper conveyance direction. Is arranged. The ink ribbon is supplied between the platen roller 4 and the line thermal head 5 by driving a winding bobbin (not shown) that rotates the winding roll.
[0022]
Further, the transporting stepping motor 7 used in the present embodiment uses a bipolar four-phase motor as an example, and as shown in FIG. 2, the first (A) and second ( B), a stator 10 having third (C) and fourth (D) magnetic poles (phases), and a rotor made of a rotatable permanent magnet having N and S poles at 180 degree intervals. An output shaft (not shown) is connected to the rotor. A first coil 12 is wound around the first (A) and third (C) magnetic poles, and a second coil 13 is wound around the second (B) and fourth (D) magnetic poles. Has been.
[0023]
When an excitation current (phase current) as a drive signal is passed through the coils 12 and 13 of each phase of the stator 10 in order to rotationally drive such a stepping motor 1, a magnetic field is generated by this current, and the stator 10 and An electromagnetic force that attracts or repels between the rotor 11 and the rotor 11 is generated. By sequentially switching the phase currents, the electromagnetic force between the stator 10 and the rotor 11 is switched, and a torque for moving the rotor 11 is obtained.
[0024]
Further, as shown in the block diagram of FIG. 3, the recording paper conveyance control and the line thermal head 5 recording control in the present embodiment are performed by the CPU 14 in the image recording data 15a and the recording control program 16a stored in the RAM 15 or ROM 16. Based on. That is, the RAM 15 stores image recording data 15a transmitted from the computer main body. The ROM 16 stores a recording control program 16a for calculating the dynamic division number based on the image recording data 15a, and one dynamic division number calculated according to the recording control program 16a. A difference value calculation program 16b for calculating an absolute value of a difference from the dynamic division number at the previous recording line is stored.
[0025]
Further, the ROM 16 stores a table 16c in which a current value of a desired magnitude to be given in advance is set for each difference absolute value calculated according to the difference value calculation program 16b. In the present embodiment, the application of a desired current value is realized by control based on the duty ratio. In practice, the energization of the stepping motor 7 for conveyance with reference to the absolute difference value of the number of divisions is turned on / off. An off timing table 16c is stored. Here, the duty ratio means a ratio of a high energization time in a high and low energization pulse cycle, a so-called duty cycle.
[0026]
Then, a desired current value is given by conducting energization control continuously by arbitrarily setting the on-time Ton and the off-time Toff.
[0027]
Further, as shown in FIG. 4, the on / off timing table 16c gives a current value ◯ slightly larger than the desired current value × when the difference absolute value of the number of divisions is 0 to 6, for example. Preset to do. Of course, the desired current value x may be set so that the actually applied current value ○ matches, or when the difference absolute value is “0”, the current value may be decreased. Good. If the difference absolute value is “0”, it is not necessary to change the speed of the transporting stepping motor. Therefore, if the driving inertia force remaining in the transporting stepping motor when the previous recording line is recorded is used. Even if the current value is decreased, the rotation speed of the motor can be maintained at a constant speed, which is efficient.
[0028]
Next, a driving method of the transporting stepping motor 7 of the present embodiment will be described with reference to the flowcharts of FIGS.
[0029]
FIG. 5 shows a procedure for developing the image recording data 15a of the present embodiment. In step ST1, the number of heating elements energized in one line is counted based on the image recording data 15a stored in the RAM 15, and X is counted. Assign to. Subsequently, the process proceeds to step ST2, where Z is a value obtained by dividing X by the predetermined maximum number Y of simultaneous heating elements, and p is a remainder that cannot be divided. In step ST3, Z + p is set to N as the division number, and the process proceeds to step ST4. The image recording data 15a for one line is divided into N pieces and stored in the recording buffer 17 together with the division number N. The development of the recording data 15a is finished.
[0030]
Subsequently, as shown in FIG. 6, in the recording control procedure, in step ST11, the division number N stored in the recording buffer 17 is taken out, and the process proceeds to step ST12 to advance the recording line immediately before, that is, the immediately preceding recording line. The number of divisions is taken to be M. In step ST13, the difference between the division number N of the current recording line and the division number M of the previous recording line is calculated, and the absolute value is obtained as J.
[0031]
Then, the process proceeds to step ST14, where the energization on / off timing table 16c stored in the ROM 16 and stored in the ROM 16 is supplied to the conveyance stepping motor 7 using the difference absolute value J of the number of divisions as a key. The difference absolute value J is inquired, and the on time Ton and the off time Toff in the active pulse at the difference absolute value J are obtained.
[0032]
Thereafter, the process proceeds to step ST15, the image recording data 15a is transferred to the line thermal head 5, and energization is started. At this time, in step ST16, the cycle in which the CPU 14 is turned on for the time Ton and turned off for the time Toff is continuously performed until the transporting stepping motor 7 rotates one step. Thereby, the electric current value of the desired magnitude | size according to the difference absolute value J of a division | segmentation number can be provided.
[0033]
In this way, recording for one line of recording lines can be sequentially advanced. If color recording is performed, the number of heating elements in the next color is obtained for each recording line, and the duty ratio according to the absolute value of the difference in the number of divisions between the current recording line and the immediately preceding recording line as described above. Repeated energization.
[0034]
According to the driving method of the transporting stepping motor 7 of this embodiment, the current value is determined according to the magnitude of the difference absolute value of the number of divisions between the current recording line and the immediately preceding recording line. Since the duty ratio is determined to apply the current and the energization control is performed, no excessive current is applied to the stepping motor for conveyance, and noise and vibration are generated by suppressing unnecessary energy application. Can be prevented.
[0035]
Further, when the difference absolute value of the number of divisions is “0”, it is not necessary to change the speed of the transporting stepping motor 7, so that the transporting stepping is performed using the motor driving inertia force at the time of recording the immediately preceding recording line. If the current value applied to the motor 7 is reduced, the current consumption value can be further saved.
[0036]
Further, in this embodiment, when the duty ratio according to the absolute value of the difference in the number of divisions is obtained, the duty ratio is obtained by using the on / off timing table 16c so that it can be quickly processed. You may make it obtain | require by a formula etc.
[0037]
【The invention's effect】
As described above, according to the first aspect of the present invention, the current value to be actually applied is determined according to the magnitude of the difference absolute value of the number of divisions between the current recording line and the immediately preceding recording line, and the number of divisions. If there is no change in the difference absolute value, the motor is driven using the inertial force of the transporting stepping motor, so that excessive current is not applied to the transporting stepping motor, which is wasteful. such energy to suppress the grant that you to prevent the generation of noise and vibration in, it is possible to further impart more efficiently current to transport stepping motor.
[0039]
According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the current value obtained according to the absolute value of the difference in the number of divisions is obtained by arbitrarily obtaining the duty ratio. Thus, a desired current value can be appropriately given.
[0040]
According to the invention of claim 3 , in addition to the effect of the invention of claim 2 , the current value corresponding to the difference absolute value of the number of divisions is regularly and appropriately applied to the conveying stepping motor. be able to.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a line printer that executes a method for driving a transport stepping motor according to the present invention. FIG. 2 is a principle diagram for explaining the structure of a transport stepping motor. FIG. 4 is a graph showing a relationship between an appropriate current value and an execution current value with respect to the absolute value of the difference in the number of divisions between the current recording line and the immediately preceding recording line. FIG. 5 is a flowchart showing a recording data development procedure in the present embodiment. FIG. 6 is a flowchart showing a recording control procedure in the embodiment. FIG. Fig. 8 shows the waveform of the current recording line and the current recording line in the conventional method of driving the stepping motor for conveyance. Graph showing the relationship between the appropriate current value and executes current value with respect to the division number of the difference absolute value between the recording line EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 1 Line printer 2 Printer main body 4 Platen roller 5 Line thermal head 7 Conveyance stepping motor 9 1st (A), 2nd (B), 3rd (C), and 4th (D) magnetic pole (phase)
10 Stator 11 Rotor 14 CPU
15 RAM
16 ROM
15a Image recording data 16a Recording control program 16b Difference value calculation program 16c On / off timing table

Claims (3)

The number of heating elements to be energized necessary for recording for one line of each color is obtained, and the stepping motor for conveying the recording paper in the case of performing divided energization so that the number of heating elements to be energized at a time is equal to or less than a predetermined number In the driving method, the difference absolute value of the number of divisions between the current recording line and the immediately preceding recording line is obtained, and when the difference absolute value is “0”, the current value applied to the conveying stepping motor is reduced. A control method for driving a transporting stepping motor, wherein control is performed such that the current value applied to the transporting stepping motor increases as the difference absolute value increases.   2. The current value to be applied based on the difference absolute value of the number of divisions between the current recording line and the immediately preceding recording line is controlled so as to obtain a predetermined duty ratio and apply it accordingly. A method of driving the stepping motor for conveyance as described.   The stepping for conveyance according to claim 2, wherein when a predetermined current value is applied according to the duty ratio, an energization on time and an energization off time are set in advance for each absolute difference value of the number of divisions. How to drive the motor.

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