JP3132733B2 - Driving method of dot print head - 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 driving a dot print head in a serial printer.

[0002]

2. Description of the Related Art Conventionally, in a dot print head, a print wire is driven by the attractive force of a permanent magnet. For example, an armature to which the print wire is fixed is swingably supported by a plate spring for bias. The armature is previously attracted to the core by a permanent magnet against the elastic force of the leaf spring, and when printing, a coil wound around the core is excited to generate a magnetic flux in a direction opposite to the permanent magnet. To release the armature.

FIG. 2 is a sectional view of a conventional dot print head. (A) of the figure shows the state when the armature is released,
(B) shows the state at the time of armature suction. In the figure, reference numeral 1 denotes a base, and a permanent magnet 2, a base plate 3, a spacer 4, and a yoke 5 are sequentially laminated on an outer peripheral edge of the base 1. Reference numeral 6 denotes a leaf spring whose fixed end is held between the spacer 4 and the yoke 5. The base of the guide 7 is overlapped on the yoke 5 via the stopper 8, while
A cap 10 is provided on the base 1 side, and the guide 7 and the cap 10 are integrally fixed by a clamp 11.

An armature 12 is swingably supported at a free end of the leaf spring 6, and a base of a printing wire 13 is fixed to a tip of the armature 12. The tip of the printing wire 13 is disposed so as to protrude forward from the center of the guide 7. Reference numeral 14 denotes a core provided at the center of the base 1. A coil 15 is wound around the outer periphery of the core 14, and both form an electromagnet. Reference numeral 16 denotes a substrate which is connected to the coil 15 and energizes the coil 15.

In the dot print head having the above-described configuration, when the coil 15 is not energized, a magnetic circuit including the base plate 3, the spacer 4, the yoke 5, the armature 12, the core 14, and the base 1 is formed by the magnetic flux generated by the permanent magnet 2. As a result, a suction force is generated between the core 14 and the armature 12. Then, the leaf spring 6 to which the armature 12 is attached is sucked and bent by the core 14, and strain energy is accumulated in the leaf spring 6.

When the coil 15 is energized in this state, the coil 15 generates a magnetic flux. This magnetic flux cancels out the magnetic flux generated by the permanent magnet 2 in the gap between the core 14 and the armature 12, so that the armature 12 is released from the core 14. At this time, the leaf spring 6 returns while releasing the accumulated strain energy, so that the tip of the printing wire 13 fixed to the armature 12 is projected from the guide 7 to fly, and an ink ribbon (not shown) is moved. The printing is performed by hitting the printing medium via the printer.

In the dot print head having the above-described structure, the magnetic flux generated by the permanent magnet 2 passes through the base 1, the core 14, passes through the armature 12, the yoke 5, the spacer 4, and the base plate 3 and returns to the permanent magnet 2 again. Each of the members for driving one print wire 13 constitutes a wire drive element. By the way, in order to reduce the size and cost of the dot print head having the above-described structure, members such as the base 1, the permanent magnet 2, and the yoke 5 to which the core 14 is fixed are common to the respective wire driving elements and are manufactured as an integral part. Often. In this case, the magnetic circuit to the wire drive element is shared in many parts. As a result, the magnetic flux generated by a certain coil 15 goes around to the magnetic circuit of another wire drive element, and changes the magnetic circuit of the wire drive element by magnetic interference.

[0008] The magnetic interference not only changes the magnetic current value of the coil 15 but also has a large effect on the operation of the armature 12, for example, a shift occurs when the armature 12 is released. In order to increase the speed and output of the dot print head, it is necessary to reduce the change in the operation of the armature 12 due to the magnetic interference.

Therefore, there has been provided a method of driving a dot print head in which the time for energizing the coil 15 is made variable by the number of coils 15 which are simultaneously excited to minimize the change in the operation of the armature 12 (Japanese Patent Publication No. 63-1988). 301
No. 54). In this case, when print data is supplied to the driver for driving the dot print head, the number of coils to be excited at the same time is detected by the detection circuit, and a signal corresponding to the number of coils is output. Is set. That is, the energization time is lengthened as the number of simultaneously excited coils increases.

[0010]

However, in the conventional method of driving a dot print head, since the control is performed only by the number of coils 15 which are simultaneously excited, the operation of the armature 12 is actually kept constant. No. This is because the influence of magnetic interference also depends on the positional relationship between the wire driving elements, and the degree of magnetic interference is different between simultaneous printing by adjacent wire driving elements and simultaneous printing by wire driving elements at distant locations. Is quite different.

For example, in the case of a 24-pin dot print head, printing can be performed under constant conditions when only one arbitrary wire driving element is driven,
Only when all the wire drive elements are driven at the same time, and when a certain number of 2 to 23 wire drive elements are driven at the same time, various combinations of the driven wire drive elements can be considered. The printing conditions vary depending on the printing conditions.

Further, not only does the magnetic flux generated by the other coil 15 that is excited at the same time wrap around, but also the magnetic flux generated by the other coil 15 that has been excited before exciting the coil 15 wraps around, or is already excited. In some cases, the residual magnetic flux of the coil 15 in which the operation has been completed may wrap around. Assuming that the excitation cycle of the coil 15 is T, the excitation cycle of the other coils 15 is also T. However, the mutual excitation timing is a time T due to the print data and the arrangement of each print wire 13.
/ 2, T / 4, T / 6, etc., and the amount of remanence of the residual magnetic flux is not constant.

FIG. 3 is an explanatory view of printing by a conventional dot print head. (A) of the figure shows the arrangement of the printing wires 13 (FIG. 2), (b) shows the printing result printed by the printing wires 13 in the arrangement of (a), (c) shows the arrangement of the other printing wires 13, (D) shows a print result printed by the print wires 13 in the arrangement of (c). For example, when using a dot print head in which two print wires 13 are arranged in a straight line in the vertical direction of the figure as shown in (a) of the figure and moving the dot print head to the left and right to perform printing, (b) In order to obtain a printing result as shown in (1), each coil 15 corresponding to the printing wire 13 must be excited with a phase difference of time T / 2.

Also, as shown in FIG.
3 uses a dot print head shifted by 1/120 inch in the left and right direction in the figure, and moves the dot print head to the left and right to perform printing. Each coil 15 corresponding to the wire 13 must be excited with a phase difference of time T / 4. As described above, when a certain coil 15 is excited, even if the number of coils 15 to be simultaneously excited is constant, the other coils 15 are moved forward by the time T / 2 and T / 4 depending on the print data and the arrangement of the print wires 13. May be excited, and printing conditions differ depending on the combination.

Therefore, usually, a combination of the wire drive elements driven simultaneously or the combination of the wire drive elements in which the operation of the armature 12 is the worst among the combinations of the wire drive elements driven with a predetermined phase difference is adopted. Thus, the energization time of the coil 15 is corrected. For this reason,
Unnecessary energy is supplied to the coil 15 to the combination of the wire driving elements which does not need to correct the energizing time for the operation of the armature 12, so that the coil 15
Heat is generated or printing power becomes excessive.

Further, the magnetic interference affects the time required for the operation of the armature 12 and the printing wire 13. When the time required for the operation becomes longer and the energization of the coil 15 starts at the next drive start timing before the armature 12 returns to the position of the core 14, the leaf spring 6
Therefore, the flight of the printing wire 13 is started in a state where the distortion of the printing wire 13 is small, and the printing power may be reduced or dot removal may occur.

The present invention solves the above-mentioned problems of the conventional method of driving a dot print head, so that unnecessary energy is not supplied to the coil, so that the printing power is reduced or dot removal occurs. It is an object of the present invention to provide a method of driving a dot print head without wobbling.

[0018]

For this purpose, a method for driving a dot print head according to the present invention comprises a plurality of wire driving elements,
Further, the present invention is applied to a dot print head having a coil arranged corresponding to each of the wire driving elements, and performing printing by energizing a predetermined coil.

Then, based on the print data, a wire drive element to be corrected is selected, and for each of the selected wire drive elements, the number of simultaneously driven wire drive elements and all of the simultaneously driven wire drive elements The relative position between the element and the selected wire drive element, and the history data of the drive of the wire drive element are calculated, and the number of the wire drive elements, the plurality of correction values stored in advance corresponding to the relative position and the history data are calculated. Is read from the memory, and the printing is performed by calculating the drive time and the drive start timing for each wire drive element based on the combination of the correction values.

Another method of driving a dot print head according to the present invention comprises a plurality of wire drive elements and a coil disposed in correspondence with each of the wire drive elements, and prints by energizing a predetermined coil. Applicable to dot print heads.

When driving the wire drive element for printing by the standard drive signal, the number of wire drive elements driven simultaneously with the wire drive element for printing by the standard drive signal is determined based on the print data. Another standard drive signal calculated including the wire drive element and set as a first number, driven within the excitation cycle immediately before the wire drive element is driven, and set differently from the standard drive signal Calculating the number of other wire drive elements to perform printing by using the second number, reading the drive time and drive start timing stored in advance from the memory based on the calculated first and second numbers, The printing is performed by driving the wire driving element at the driving time and the driving start timing. Further, the another standard drive signal has the same excitation cycle as the standard drive signal, and is set so as to differ by a predetermined phase difference within the range of the excitation cycle.

[0022]

According to the present invention, as described above, the method for driving a dot print head includes a plurality of wire driving elements and coils arranged in correspondence with the respective wire driving elements, and energizes a predetermined coil. The present invention is applied to a dot print head for performing printing.

Then, based on the print data, a wire drive element to be corrected is selected, and for each of the selected wire drive elements, the number of simultaneously driven wire drive elements and all the simultaneously driven wire drive elements The relative position between the element and the selected wire drive element, and the history data of the drive of the wire drive element are calculated, and the number of the wire drive elements, the plurality of correction values stored in advance corresponding to the relative position and the history data are calculated. Is read from the memory, and the printing is performed by calculating the drive time and the drive start timing for each wire drive element based on the combination of the correction values.

In this case, the wire drive elements to be corrected are selected based on the print data, and for each of the selected wire drive elements, the number of simultaneously driven wire drive elements and all the simultaneously driven wire drives The relative position between the driving element and the selected wire driving element, and the history data of the driving of the wire driving element are calculated. Then, a plurality of correction values stored in advance corresponding to the number, relative position, and history data of the wire driving elements are read from the memory, and the driving of each wire driving element is performed based on the combination of the correction values. The time and the drive start timing are calculated.

Another driving method of the dot print head according to the present invention comprises a plurality of wire driving elements and a coil arranged corresponding to each of the wire driving elements, and prints by energizing a predetermined coil. Applicable to dot print heads.

When driving the wire drive element for printing by the standard drive signal, the number of wire drive elements driven simultaneously with the wire drive element for printing by the standard drive signal is determined based on the print data. The first number is calculated by including the wire driving element, and another standard drive set within a range of the excitation cycle immediately before the wire driving element is driven and set differently from the standard drive signal The number of other wire drive elements that perform printing by a signal is calculated as a second number, and the drive time and drive start timing stored in advance are read from the memory based on the calculated first and second numbers. Then, the wire drive element is driven at the drive time and the drive start timing to perform printing. Further, the another standard drive signal has the same excitation cycle as the standard drive signal, and is set so as to differ by a predetermined phase difference within the range of the excitation cycle. In this case, when driving the wire drive element that performs printing by the standard drive signal, the number of wire drive elements that are driven simultaneously with the wire drive element based on the print data and perform printing by the standard drive signal is determined by the wire drive element. The first number is calculated including the element, and the wire drive element is driven within the range of the excitation cycle immediately before being driven,
The number of other wire drive elements for performing printing based on another standard drive signal set differently from the standard drive signal is calculated and set as a second number. Then, based on the calculated first and second numbers, the driving time and the driving start timing stored in advance are read out from the memory, and the wire driving element is driven and printed by the driving time and the driving start timing. Is performed.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a control block diagram of a serial printer adopting the dot print head driving method of the present invention, and FIG. 4 is an explanatory diagram of a printing operation in the dot print head driving method of the present invention.

In FIG. 4, # 1 to # 24 indicate 24 wire drive elements, and each wire drive element is arranged in a ring. (A) and (b) of the figure show the driving state of the wire driving element at a certain point during the printing operation.
The wire drive element indicated by is driven, and the wire drive element indicated by ○ is not driven. Also, FIG.
In (2), the wire drive elements # 1, 2, 5 are simultaneously driven, and in (b) of FIG. 7, the wire drive elements # 1, 21, 24 are simultaneously driven.

Here, a printing operation when printing is performed in the driving state of the wire driving element shown in FIG. 4A will be described with reference to FIG. In FIG. 1, reference numeral 21 denotes a CPU for controlling the entire printer, 22 denotes a correction pin selection circuit for selecting a wire drive element to be subjected to a correction process, and 23
Is a pin-to-pin relative position calculation circuit for calculating the relative position between the simultaneously driven wire drive elements and the number of simultaneously driven wire drive elements, that is, the number of simultaneously driven pins;
Is a correction value memory for storing a correction value serving as a basis for correcting the drive time of the wire drive element; 25 is a correction value calculation circuit for calculating the correction value stored in the correction value memory 24;
Reference numeral 6 denotes a pin drive timer for generating a drive time of the wire drive element, reference numeral 27 denotes a drive circuit for supplying a drive current to the wire drive element, and reference numeral 28 denotes a dot print head.

A pin data storage circuit 29 stores data of the driven wire driving element, a pin data comparison circuit 30 compares driving history data, and a correction of drive start timing of the wire driving element 31. A correction value memory for storing a correction value serving as a basis for the correction value calculation, a correction value calculation circuit 32 for calculating the correction value stored in the correction value memory 31, and a correction value memory 33 for correcting the drive start timing of the wire drive element It is a drive timing timer.

The CPU 21 first converts the print data a into a correction pin selection circuit 22, an inter-pin relative position calculation circuit 23, a correction value calculation circuit 25, a pin drive timer 26, a pin data storage circuit 29, and a pin data comparison circuit 30. Write to a register not shown. Next, the CPU 21 turns on the correction processing start signal b, whereby the correction processing is started.

The correction pin selection circuit 22 controls the wire drive elements driven based on the print data a in # 1 and # 2 in FIG.
.., # 24. FIG. 4 (a)
In the case of (1), first, the wire drive element # 1 is selected, and the pin number c to be corrected is sent to the inter-pin relative position calculation circuit 23 and the pin data comparison circuit 30. The inter-pin relative position calculation circuit 23 calculates the number of simultaneously driven pins based on the print data a, and sets the relative position between the pin number c to be corrected and the driven wire drive element in the print data a to # 1, #
, # 3,..., # 24 are calculated in the order of the wire drive elements,
The storage address d of the correction value corresponding to each simultaneous drive pin number and relative position is output. In the case of FIG. 4A, the number of simultaneously driven pins is 3, and each of the # 1, # 2, and # 5 driven wire drive elements is driven against the # 1 wire drive element to be corrected. Are 0, 1, and 2 respectively.

The pin data comparison circuit 30 stores the correction target pin number c and the driving history data read out from the pin data storage circuit 29, for example, the pin of the previously driven wire driving element or the pin of the previously driven wire driving element. The number k is compared, and the storage address m of the correction value corresponding to the comparison result is output. The storage addresses d and m are input to the correction value memories 24 and 31. Therefore, the correction value memories 24 and 31 store the correction value storage addresses d and m by inputting the correction value storage addresses d and m.
The correction values e and n stored in advance corresponding to the number of simultaneously driven pins 3 and the relative positions 0, 1, and 2 are output to the correction value calculation circuits 25 and 32, respectively. In this case, the relative position is 0, 1, 2,..., 12, and the relative position with respect to the # 1 wire drive element is 12 at the maximum in the case of the # 24 wire drive element. When the storage address m of the correction value is input, the correction value memories 24 and 31 change the correction table corresponding to the driving history data to change the correction values e and n.
Are output to the correction value calculation circuits 25 and 32, respectively.

The correction value calculation circuits 25 and 32 are provided with # 1,
The correction values e and n of the wire drive elements # 2 and # 5 are received, a predetermined operation is performed on each of the correction values e and n, and the correction values e and n of the last wire drive element # 5 are received. rear,
The calculation results f and p are written to the channels corresponding to the wire drive elements to be corrected in the pin drive timer 26 and the drive timing timer 33, respectively.

Then, the correction value calculation circuit 25 sends a one-pin correction end signal g to the correction pin selection circuit 22 to notify the end of the correction processing for each wire drive element. Subsequently, the correction pin selection circuit 22 outputs the next correction target pin number c,
The same correction processing is performed. When this operation is repeated up to the last wire drive element in the print data a, the correction pin selection circuit 22 sends a correction end signal h to the CPU 21 to notify the end of the correction processing.

At a predetermined timing after completion of the correction processing, the CPU 21 turns on the timer start signal i to cause the drive timing timer 33 to start counting, and starts driving the wire drive element by the timer output q. Then, the counting of the pin drive timer 26 is started. The pin drive timer 26 counts a value corresponding to the drive time, and during this time, the dot print head 28 is driven via the drive circuit 27 to perform printing.

FIG. 5 is a waveform diagram of the exciting current of the coil by the driving method of the dot print head according to the present invention. In the drawing, a broken line α is an exciting current in a driving state as shown in FIG. 4A, and a solid line β is an exciting current in a driving state as shown in FIG. Next, a case in which the correction process is performed to print an actual character will be described.

FIG. 6 is a diagram showing a dot pattern of a character to be printed, FIG. 7 is a diagram showing an example of a timing chart after a correction process, and FIG. 8 is a diagram showing an example of a correction table. FIG. 8A shows a correction table based on the number of simultaneously driven pins, and FIG.
Shows a correction table based on driving history data, (c) shows a correction table based on the presence or absence of an adjacent drive pin, and (d) shows a correction table of drive start timing based on the sum of correction values of drive timing.

In FIG. 6, the character "B" has 12 columns.times.2
It is developed as a pattern in a 4-pin dot matrix. In this case, the odd-numbered pins and the even-numbered pins are grouped in timing, and each of the odd-numbered pins or the even-numbered pins is placed in a state where it can be driven simultaneously by receiving the respective drive currents. Actually, the wire drive element corresponding to the print data is selectively driven.

For example, in the case of the ninth column, the third, fourth, fifth,
Nine pins of ninth, tenth, twelfth, thirteenth, nineteenth, and twentieth pins are driven, but odd-numbered third, fifth, ninth, thirteenth, and nineteenth pins are simultaneously driven. Then, the even-numbered fourth, tenth, twelfth, and twentieth pins are simultaneously driven at the next timing. In FIG. 4, first, # 3, # 5,
The wire drive elements of # 9, # 13, and # 19 are replaced with # 4,
The wire drive elements # 10, # 12, and # 20 are simultaneously driven. Then, the drive time and drive timing are corrected for each wire drive element that is driven simultaneously.

In FIG. 7, the standard driving time and the standard driving
The drive time of each wire drive element after timing correction and
The drive timing is shown. For example, the third in the eighth column
In the case of pins, the drive time is compensated for
Δt₁In the case of the fourth pin in the ninth row,
Imming is corrected by Δt from standard drive timing _Two
Has only been late. Thus, the third, fourth, and fourth
5th, 9th, 10th, 12th, 13th, 19th, 20th
Correction is performed for all wire drive elements in the
Each drive time and drive timing are set.

Next, a description will be given of each correction value which is the basis of a calculation for setting the drive time and drive timing of each wire drive element driven simultaneously. In FIG.
(A) shows a correction value for correcting the drive time and the drive timing based on the number of simultaneously driven pins. For example, if the standard drive time is 76 ms and the correction value of the standard drive timing is 0 ms, the third, fifth, ninth, and first
When the third and nineteenth pins are driven, the number of pins that are driven simultaneously is 5, so that the correction value of the driving time is +3 ms and the correction value of the driving timing is +3 ms.

FIG. 7B shows a correction value set depending on whether or not the dot line has been driven in the preceding dot row. For example, in the correction processing of the third pin in the ninth row, the third pin is also driven in the eighth row, so that the correction value of the drive time is -2 ms, and the correction value of the drive timing is +1.
ms. (C) shows a correction value that is set to eliminate the effect caused by driving an adjacent wire driving element. For example, in the correction processing of the third pin in the ninth row, the fourth pin is driven at the same time and in the one-side adjacent state, so that the correction value of the drive time is +2 ms and the correction value of the drive timing is +2 ms.

(D) is to delay the drive start timing from the standard drive timing when the sum of the drive timing correction values obtained from the respective correction tables (a) to (c) exceeds a certain value. 6 is a correction table for indicating a correction value to be set. For example, in the correction processing of the third pin in the ninth column, the correction value of the drive timing is +3 ms in the case of (a), +1 ms in the case of (b), and (c).
Is +2 ms, the sum of them is +6 ms. Therefore, the drive start timing correction value is +2 m.
s. On the other hand, although not shown, there is also provided a correction table for changing the standard driving time corresponding to the total value of the correction values of the driving time obtained by the respective correction tables (a) to (c), The driving time is changed by the correction table.

As described above, the drive time and drive timing are corrected for each wire drive element of each dot row. Next, a second embodiment of the present invention will be described. FIG. 9 is a control block diagram of a serial printer adopting a method of driving a dot print head according to a second embodiment of the present invention.

In the figure, reference numeral 21 denotes a CPU for controlling the entire printer, 36 denotes a simultaneous driving pin number calculating circuit for calculating the number of simultaneously driven wire driving elements, 3
Reference numeral 7 denotes data of the number of simultaneous drive pins calculated by the simultaneous drive pin number calculation circuit 36, which is calculated by the time T / N from the next drive timing.
T / N previous driving pin number storage circuit for storing data of the number of driving pins before (N: integer), 38 is a correction value memory for storing the driving time of the wire driving element,
26 is a pin drive timer for generating a drive time of the wire drive element, 27 is a drive circuit for supplying a drive current to the wire drive element, and 28 is a dot print head.

Reference numeral 39 denotes a correction value memory for storing the drive start timing of the wire drive element, and reference numeral 33 denotes a drive timing timer for correcting the drive start timing of the wire drive element. First, the CPU 21 sets the time T
When the print data a for driving the wire drive element is written at a timing of every / 4 into the simultaneous drive pin number calculation circuit 36 and a register (not shown) in the pin drive timer 26, the correction process is started.

The simultaneous drive pin number calculation circuit 36 calculates data on the number of simultaneous drive pins based on the print data a,
The storage address s of the corresponding correction value is output. The calculated data is stored in the T / N pre-drive pin number storage circuit 37 in preparation for the next timing. The T / N pre-drive pin number storage circuit 37 has already stored the previous timing (time T / 4 before) and the timing two times before (time T / 2).
The data of the number of drive pins in the preceding step) is stored, and the T / N preceding drive pin number storage circuit 37 outputs the storage address r of the corresponding correction value.

The storage addresses s and r are input to correction value memories 38 and 39. When the storage addresses s, r are input, the correction value memories 38, 39 receive the number of simultaneously driven pins, T
The calculation result f stored in advance corresponding to the number of / 4 previous drive pins and the number of T / 2 previous drive pins, that is, the corrected drive time is driven to the pin drive timer 26, and the calculation result p, that is, the corrected drive timing is driven. Timing timer 33
Output to

At a predetermined timing, the CPU 21 turns on a timer start signal i to cause the drive timing timer 33 to start counting, and the wire drive is performed by a timer output q generated after a predetermined time based on the calculation result p. The driving of the element is started, and the pin driving timer 26 starts counting the value corresponding to the operation result f.
, The dot print head 28 is driven to perform printing.

FIG. 10 is a diagram showing a dot pattern of a character to be printed in the second embodiment of the present invention, FIG. 11 is a time chart when no correction processing is performed, and FIG. 12 is a diagram in the second embodiment of the present invention. FIG. 13 is a diagram showing an example of a correction table according to the second embodiment of the present invention. 11 and 12, S1 is a standard drive signal of the first to twelfth pins, and S2 is a thirteenth to second pin.
4 shows a standard drive signal of pin 4. 13A shows a correction table based on the number of simultaneously driven pins, FIG. 13B shows a correction table based on the number of driving pins before time T / 4, and FIG. 13C shows a time T / 2.
6 shows a correction table based on the number of front drive pins.

In FIG. 10, the character "B" has 13 columns.
It is developed as a pattern in a 24-pin dot matrix. In the case of a dot print head in which the first to twelfth pins and the thirteenth to twenty-fourth pins are respectively arranged on a 1/180 inch grid and the grids are shifted by 1/360 inch, 1st to 12th pins and 13th
The twenty-fourth to twenty-fourth pins are grouped in drive timing, and upon receiving respective timing signals, the first to twelfth pins or the thirteenth to twenty-fourth pins are placed in a state where they can be driven simultaneously. Actually, the wire drive element corresponding to the print data a is selectively driven.

For example, in the case of the fifth row, three pins of the fourth, twelfth, and nineteenth pins are driven. As shown in FIG. 11, the fourth and twelfth pins are driven simultaneously, and the nineteenth pin is driven. The pins are driven at another timing, a time (3/4) T later. Then, the drive time and drive timing are corrected every time T / 4. FIG. 12 shows the drive time and drive timing of each pin after correction.

For example, in the case of the fourth and twelfth pins in the fifth row, the drive timing is corrected to be delayed by Δt ₁ from the standard drive timing, and the drive time is further corrected to be Δt ₂ than the standard drive time. Have been long. As described above, the correction processing is performed for all the pins every time T / 4, and the driving time and the driving timing are set.

Next, with reference to FIG. 13, description will be given of each correction value which is the basis of calculation for setting the drive time and drive timing of the driven pin. (A) of FIG.
It shows a correction value for correcting the drive time and drive timing based on the number of simultaneously driven pins. For example, the standard drive time is 100 μs, and the correction value of the standard drive timing is 0.
When the fourth and twelfth pins are driven at the same time, the number of pins driven at the same time is two, so that the correction value of the driving time is +2 μs and the correction value of the driving timing is +2 μs.

FIG. 9B shows a correction value set by the number of driven pins at the drive timing before time T / 4. For example, since seven of the thirteenth to nineteenth pins were driven before the time T / 4 during which the fourth and twelfth pins are simultaneously driven, the correction value of the driving time is +4 μm.
s, and the correction value of the drive timing is +5 μs.

FIG. 9C shows the time T similarly to FIG.
A correction value set by the number of pins driven at the drive timing before / 2 is shown. For example, only the third pin is driven before the time T / 2 during which the fourth and twelfth pins are driven simultaneously. Therefore, the correction value of the drive time and the correction value of the drive timing are both 0 μs. The addition result of each correction value obtained as described above is
9 is written to the correction value memories 38 and 39 in FIG. 9 by the input of the storage address r from the T / N pre-drive pin number storage circuit 37 and the input of the storage address s from the simultaneous drive pin number calculation circuit 36. Can be read.

FIG. 14 is a time chart showing an example of a drive current waveform according to the second embodiment of the present invention. In the figure, i ₃ is the drive current waveform of the third pin, i ₁₂ is the drive current waveform of the twelfth pin, i ₁₃ is the drive current waveform of the thirteenth pin, F is the flight waveform of the twelfth pin, and S ₁₂ is It is a drive signal waveform of the 12th pin. It should be noted that the numbers added in the vicinity of each waveform indicate the sequence of each data constituting the print data a.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the present invention.

[0060]

As described above in detail, according to the present invention, a method for driving a dot print head includes a plurality of wire driving elements and a coil arranged corresponding to each of the wire driving elements. The present invention is applied to a dot print head that performs printing by energizing a predetermined coil. Then, based on the print data, a wire drive element to be corrected is selected, and for each selected wire drive element, the number of simultaneously driven wire drive elements and the selection of all simultaneously driven wire drive elements are selected. The relative position with respect to the wire drive element and the history data of the drive of the wire drive element are calculated, and a plurality of correction values stored in advance corresponding to the number of the wire drive elements, the relative position and the history data are stored in the memory. Reading, based on the combination of each of the correction values,
Printing is performed by calculating the drive time and drive start timing for each wire drive element.

In this case, the effect of receiving magnetic interference from all the simultaneously driven wire driving elements can be eliminated, so that unnecessary energy is not supplied to the coil. It is possible to prevent the time required for the operation from being changed and the printing power from being reduced and the occurrence of dot removal or the like not occurring.

Another method of driving a dot print head according to the present invention includes a plurality of wire drive elements and coils arranged in correspondence with the respective wire drive elements, and prints by energizing a predetermined coil. Applicable to dot print heads. Then, when driving the wire drive element that performs printing by the standard drive signal, based on the print data,
The number of wire drive elements that are driven at the same time as the wire drive element and perform printing based on the standard drive signal is calculated including the wire drive element as the first number, and the excitation immediately before the wire drive element is driven is calculated. The number of other wire drive elements that are driven within the period and are to be printed by another standard drive signal set differently from the standard drive signal is calculated as a second number, and the calculated first number is calculated. Based on the second number, the driving time and the driving start timing stored in advance are read from the memory, and the wire driving element is driven at the driving time and the driving start timing to perform printing. Further, the another standard drive signal has the same excitation cycle as the standard drive signal, and is set so as to differ by a predetermined phase difference within the range of the excitation cycle. In this case, when driving the wire drive element to be corrected,
It is possible to eliminate the influence of the residual magnetic flux wrapping around from the coils of the wire drive element that is driven simultaneously and the other wire drive elements that are already excited. Therefore, not only is unnecessary energy supplied to the coil, but also the time required for the operation of the wire drive element is changed, so that the printing power is not reduced and the dot removal is prevented. .

[Brief description of the drawings]

FIG. 1 is a control block diagram of a serial printer in which a method of driving a dot print head according to the present invention is adopted.

FIG. 2 is a sectional view of a conventional dot print head.

FIG. 3 is an explanatory diagram of printing by a conventional dot print head.

FIG. 4 is an explanatory diagram of a printing operation in a method of driving a dot print head according to the present invention.

FIG. 5 is a waveform diagram of an exciting current of a coil according to a method of driving a dot print head according to the present invention.

FIG. 6 is a diagram showing a dot pattern of a character to be printed.

FIG. 7 is a diagram illustrating an example of a timing chart after a correction process.

FIG. 8 is a diagram illustrating an example of a correction table.

FIG. 9 is a control block diagram of a serial printer adopting a method of driving a dot print head according to a second embodiment of the present invention.

FIG. 10 is a diagram showing a dot pattern of a character to be printed in a second embodiment of the present invention.

FIG. 11 is a time chart when the correction process is not performed.

FIG. 12 is a time chart after a correction process according to the second embodiment of the present invention.

FIG. 13 is a diagram illustrating an example of a correction table according to the second embodiment of the present invention.

FIG. 14 is a time chart showing an example of a drive current waveform according to the second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 21 CPU 22 Correction pin selection circuit 23 Relative pin position calculation circuit 24, 31, 38, 39 Correction value memory 25, 32 Correction value calculation circuit 26 Pin drive timer 27 Drive circuit 28 Dot print head 29 Pin data storage circuit 30 Pin data Comparison circuit 33 Drive timing timer 36 Simultaneous drive pin number calculation circuit 37 T / N previous drive pin number storage circuit

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Motonobu Hatakeyama 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-2-151450 (JP, A) JP-A-2-69249 (JP, A) JP-A-1-174454 (JP, A) JP-A-59-42968 (JP, A) JP-A-2-204055 (JP, A) JP-A-63-130355 (JP JP, A) JP-A-62-174166 (JP, A)

Claims (2)

(57) [Claims] 1. A method of driving a dot print head, comprising: a plurality of wire driving elements; and coils arranged in correspondence with the respective wire driving elements, wherein the printing is performed by energizing a predetermined coil. A) selecting a wire drive element to be corrected based on the print data; and (b) for each of the selected wire drive elements, the number of simultaneously driven wire drive elements and all of the simultaneously driven wire drive elements. And the relative position of the selected wire drive element and the history data of the drive of the wire drive element are calculated. (C) A plurality of data stored in advance corresponding to the number, relative position and history data of the wire drive element The correction value is read from the memory, and (d) a driving time and a driving start timing for each wire driving element are calculated and marked based on the combination of the correction values. The driving method of the dot print head and performing. 2. A method for driving a dot print head, comprising: a plurality of wire driving elements; and coils arranged in correspondence with the respective wire driving elements, wherein the printing is performed by energizing a predetermined coil. ) Wire drive element that prints with standard drive signal
When driving the wire , the wire
Driven at the same time as the drive element , printing with standard drive signals
Including the wire drive elements the number of wire driving elements for
To calculate the first number , and that the wire driving element is driven.
Driven within the excitation cycle immediately before
With another standard drive signal set differently from the drive signal
The calculated number of other wire driving device for printing I 2
A number of first is (b) calculating, based on the second number, reads the drive time and the driving start timing stored in advance from the memory, the wire in (c) the driving time and drive start timing
Performs printing by driving the Ya driving element, (d) the further standard drive signal to the standard drive signals, have the same excitation period, differ by a predetermined phase difference in the range of excitation cycle the driving method of dot printing head was characterized by Tei Rukoto is set.