JP3064656B2 - Printhead drive control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control method for a wire dot type print head which performs dot printing by driving a print wire on a print medium.

[0002]

2. Description of the Related Art It is known to drive a wire dot type print head of this type by adding a pulse having a size that does not lead to printing (hereinafter, referred to as a brake pulse) after an energizing pulse for dot driving. . In general, the printing speed is faster when the brake pulse is not applied, but the stress of the collision of the printing wire with the stopper is reduced (secondary bound suppression) and the special printing (double speed or one line is divided into odd and even dots). In the case of two-pass printing, etc.), it is necessary to control and adjust the printing speed. Therefore, a brake pulse may be added for every dot drive.

FIGS. 6 and 7 show a conventional driving method in which a brake pulse is added after all the dot driving pulses. FIG. 6 shows the timing and printing of the energizing pulse and the brake pulse for continuous dot driving (continuous printing). Wire displacement characteristics,
FIG. 7 shows the timings of the energizing pulse and the brake pulse for single dot drive (single printing) and the displacement characteristics of the printing wire. As can be seen from these figures, the constant energizing time A and the brake pulse B
(Secondary bound control pulse) are energized at the same timing and at the same energizing time. Further, in the case of single-shot dot drive, it is equivalent to the first dot of continuous dot drive.

FIGS. 8 and 9 show a conventional driving method in which a brake pulse is added only after the last dot driving pulse. FIG. 8 shows the timing of the energizing pulse and the brake pulse of the continuous dot drive, the displacement characteristics of the printing wire,
FIG. 9 shows the timings of the energizing pulse and the brake pulse for single dot drive and the displacement characteristics of the printing wire. The waveforms of the energizing pulse and the brake pulse shown in the figure are the driving waveforms of the switching element for applying power to the actuator for driving the print wire, and are not the waveforms of the current flowing through the actuator. Actually, there is a slight delay from when the pulse is generated until the driving force is transmitted to the printing wire.

[0005]

By the way, as a result of experiments, the applicant of the present invention has found that the optimal drive energizing pulse width and brake are optimal for the first shot of single dot drive or continuous dot drive and the second and subsequent shots of continuous dot drive. It was found that the pulse width was different. That is, even if the secondary bound control is appropriately set in the single dot drive, the secondary bound generated after the final dot drive cannot be controlled even if the same control is performed in the continuous dot drive, and the printing control operation follows. Not good. As a result, there arises a problem that printing density and printing ghost occur. That is, as shown by the waveform Ma of the deformation characteristic graph of the print wire shown in FIGS. 6 and 8, the secondary bound cannot be controlled. This is considered to be the result of increasing the repulsion when the energy of the single dot drive is increased in order to obtain the same density in the single dot drive and the continuous dot drive.

The present invention solves the above-mentioned problems, and can perform appropriate secondary bound control for single-shot dot drive or continuous dot drive, thereby preventing the occurrence of print shading and print ghost. An object of the present invention is to provide a drive control method for a print head.

[0007]

In order to achieve the above object, according to the present invention, a print dot is formed by driving a print wire with respect to a print medium and forming a dot by a set of the dots. A drive control method for a printhead, comprising: a drive pulse for driving a single dot in which no dots are formed at least before and after a predetermined period; and a drive pulse for driving the last dot of a continuous dot row, the size of which does not lead to printing. pulses adds and lead pulse and timing of which does not reach the print to be added after the energizing pulse of a drive for the last dot of the continuous dot train, the printing to be added after the energizing pulse of a drive against the single dot This is different from the timing of the non-pulse. Further, the present invention according to claim 2 provides a printing method
A print wire is driven on the medium to form dots
And a wire dot type printer that prints with the set of dots.
A drive control method for a lint head, at least
For a single dot where no dot is formed
Dynamic energizing pulse and the last dot of a continuous dot row.
After the driving of the driving pulse you, the size does not lead to printing
Of the continuous dot row.
Mark added after the energizing pulse for driving the last dot
The timing of the pulse that does not lead to the
Does not result in printing added after the energizing pulse of the drive
This is shorter than the pulse timing.

[0008]

According to the above method, and after the energizing pulse of at least single-dot drive, after the energizing pulse the final dot drive continuous dot train, the magnitude of the pulse that does not lead to printing
When the ( brake pulse ) is added, the timing of the brake pulse added after the energizing pulse of the last dot drive of the continuous dot row and the timing of the brake pulse added after the energizing pulse of the single dot drive are made different from each other.
And appropriate secondary bound control becomes possible. Ma
Also, make the former timing shorter than the latter timing.
However, the secondary bounce can be controlled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the method of the present invention will be described below with reference to the drawings.

FIG. 1 shows an energizing pulse in the case of continuous dot driving (hereinafter referred to as "continuous printing") according to the first embodiment of the present invention, followed by a pulse of a size which does not lead to printing (hereinafter referred to as a "brake pulse"). 3) shows the timing and the displacement characteristics of the print wire. FIG. 2 shows an equivalent diagram in the case of single-shot dot drive (hereinafter, referred to as single-shot printing). The waveforms of the energizing pulse and the brake pulse shown in the figure are the driving waveforms of the switching element for applying power to the actuator for driving the print wire, and are not the waveforms of the current flowing through the actuator. Actually, there is a slight delay from when the pulse is generated until the driving force is transmitted to the printing wire. The energizing time, the brake pulse width, and the timing are separately set and controlled so as to correspond to single shot printing and continuous printing, respectively. Specifically, the energizing time A2 of the second and subsequent driving pulses of the continuous printing is set shorter than the energizing time A1 of the first driving pulse of the single-shot printing or the continuous printing.

In addition, the brake pulse B1 after the first drive pulse of continuous printing or the brake pulse B1 after the second drive pulse of continuous print is compared with the brake pulse B1 after the first drive pulse of continuous print.
The pulse width of No. 2 is set short. Further, the brake pulse timing C2 for the second and subsequent continuous printing is set shorter than the brake pulse timing C1 from the start of energization of the first dot drive pulse for single printing or continuous printing. The energization of the second and subsequent dot drive pulses is delayed by a delay time D from the start of the printing cycle T. By performing the above control, the secondary bounce can be suppressed as shown by the waveform Mb.

FIG. 3 shows the timings of the energizing pulse and the brake pulse added thereafter and the displacement characteristics of the printing wire in the case of continuous printing according to the second embodiment of the present invention. Separate energization times, brake pulse widths and timings are set and controlled for the second and subsequent shots of continuous dot drive and the final dot drive. Specifically, the setting is the same as that of FIG. 1, and the energizing time Ae of the final dot drive, the width of the brake pulse Be and the brake pulse timing time Ce are the energizing times A of the earlier dot drive.
2. The pulse width of the brake pulse B2 is set shorter than the brake pulse timing time C2. By performing the above control, as shown in waveform M e can suppress secondary bound.

FIG. 4 shows pulse timing and print wire displacement characteristics when a brake pulse is added only after an energizing pulse and a final drive pulse in continuous printing according to a third embodiment of the present invention. FIG. 5 shows an equivalent diagram for single shot printing. Also in this case, separate energizing time, brake pulse width and timing thereof are set and controlled for single shot printing and continuous printing. Specifically, the energizing time A2 of the second and subsequent driving pulses of the continuous printing is set shorter than the energizing time A1 of the first driving pulse of the single-shot printing or the continuous printing. Also, the brake pulse B after the one-shot printing
In contrast to 1, the pulse width of the brake pulse Be after the final drive pulse for continuous printing is set shorter. Furthermore, the brake pulse timing Ce after the last dot drive of continuous printing is set shorter than the brake pulse timing C1 from the start of energization of the dot drive pulse for single printing. By performing the above control, the secondary bounce can be suppressed as shown by the waveform Md.

As described above, the energizing time of the dot and the energizing time of the brake pulse are determined under the following conditions.

(A) Single dot (b) First consecutive dot (c) Second consecutive dot and other than the last (d) Final consecutive dot These are hereinafter referred to as conditions a to d. Hereinafter, the third embodiment will be described with reference to a circuit that determines these conditions a to d. Here, for easy understanding,
It is assumed that the terminals A, B, and C in FIGS. 11A to 11D are connected in parallel to the terminals A, B, and C in FIG. The shift register 11 has a print wire 1 developed by dots from an image buffer in which print data is temporarily stored.
Serial data per pin and a clock that determines the timing of sending this data are input. The data input this time, the data input last time, and the data input last time are output to the output terminals A, B, and C of the shift register 11, respectively, and each output is the next print data, the current print data, and the last print data. Print data.

First, the circuit (a) will be described. In this circuit, terminal B is on (there is a dot this time)
If the terminals A and C are off (no previous and next dots), the output is turned on. Therefore, the condition a can be determined by this circuit. If the output of the circuit (a) is on, the energizing time of the energizing pulse is set to A1. After C1 has elapsed from the start point of the pulse (C1 is the brake pulse timing), the energizing time B1
Generates a brake pulse.

Next, regarding the circuit of FIG.
All of B are on (this time, next time have dots)
Thus, the output is turned on only when the terminal C is off (no dot in the previous time). Therefore, the condition b can be determined by the circuit of FIG. When the circuit (b) outputs ON, a pulse for the energization time A2 is generated. This A2 and the previous A1 satisfy the relationship of A1> A2.

Next, in the case of the circuit of FIG.
The output is turned on only when both B and C are on (previous, present, and next time dots are present). Thus, the condition (c) can be determined by the circuit (c). When the circuit of (c) outputs ON, a pulse is generated after a delay time D, and the energizing time is set to A2. This A2 and the previous A1 are A1
> A2 is satisfied.

Next, in the case of the circuit (d), when the terminal B and the terminal C are turned on (the present and previous dots are present) and the terminal A is turned off (the next dot is absent), the output is outputted. Turns on. Therefore, the condition d can be determined. When the circuit of (d) is turned on, a pulse is generated after a delay time D, and the energizing time is set to A2. After the lapse of Ce from the start point of the pulse (Ce
Is a brake pulse timing), and generates a brake pulse for the energization time Be. At this time, Be <B1, Ce
<C1. This makes it possible to appropriately control the drive of the print head. As described above, according to the present embodiment, the pulse timing is changed so as to be optimal in addition to the brake pulse energizing time between the single shot and the continuous last, so that a higher effect can be obtained.

Specifically, the brake pulse timing C
When both 1 and Ce are 180 [μs], A1 is 1
10 [μs], A2 is set to 90 [μs], and the brake pulse energization time is set to B1 = 50 [μs] for single-shot printing, and Be = 30 [μs] for continuous printing, so that the appropriate Subsequent bound control could be performed, and the density and ghost of the print could be prevented.

Also, the brake pulse energizing time B1, Be
When both are set to 50 [μs], A1 is set to 110 [μs].
s] and A2 are set to 90 [μs], and the brake pulse timing is set to C1 = 180 [μs] for single-shot printing, and to Ce = 200 [μs] for continuous printing, so that appropriate secondary bound control is performed in any printing. Was performed, and the density and ghost of the print could be prevented.

Although the present invention has been described in the above embodiment in which single energization time and brake pulse width and timing thereof are set and controlled separately for single shot printing and continuous printing, the present invention is not limited to this. Deformation is possible, for example,
A brake pulse is added after at least the energizing pulse of the single dot drive and the energizing pulse of the last dot drive of the continuous dot row, and the timing of the brake pulse after the energizing pulse of the last dot drive of the continuous dot row, A predetermined effect can be obtained by separately setting the timing of the brake pulse after the energizing pulse of the single-shot dot drive and setting the former shorter than the latter.

[0023]

As described above, according to the present invention, the timing of a pulse that does not lead to printing and is added after the energizing pulse for driving for forming the last dot of a continuous dot row,
Causing the timing of the pulses does not reach the print to be added after the energizing pulse of a drive for forming separately set different
This makes it possible to perform appropriate secondary bound control for single dot drive and continuous dot drive, respectively.
It is possible to prevent the occurrence of shading and ghost of printing. single
Printing added after energizing pulse of drive for dot generation
Than the timing of the pulse that does not reach
Mark added after the energizing pulse of the drive for forming the final dot
By shortening the timing of pulses that do not
However, secondary bounce control can be performed properly.
You.

[Brief description of the drawings]

FIG. 1 is a diagram showing a current supply timing and a printing wire displacement characteristic in a case of continuous dot driving according to a first embodiment of the method of the present invention.

FIG. 2 is a diagram equivalent to the above in the case of single dot drive.

FIG. 3 is a diagram showing the energization timing and the displacement characteristics of a printing wire in the case of continuous dot driving according to a second embodiment of the method of the present invention.

FIG. 4 is a diagram showing the energization timing and the displacement characteristics of a print wire in the case of continuous dot driving according to a third embodiment of the method of the present invention.

FIG. 5 is a diagram equivalent to the above in the case of single dot drive.

FIG. 6 is a diagram illustrating a current supply timing and a displacement characteristic of a printing wire in a conventional continuous dot driving method.

FIG. 7 is a diagram showing a current supply timing and a displacement characteristic of a printing wire in a conventional single-shot dot driving method.

FIG. 8 is a diagram showing the energization timing and the printing wire displacement characteristics when a brake pulse is added only after the last dot drive in the conventional continuous dot drive method.

FIG. 9 is a diagram showing the energization timing and print wire displacement characteristics in a conventional single-shot dot driving method.

FIG. 10 is a diagram illustrating a partial block configuration for determining whether to perform single-shot dot driving, continuous initial dot driving, or continuous final dot driving.

FIG. 11 is a diagram showing a partial specific configuration for determining whether to perform single-shot dot driving, continuous initial dot driving, or continuous final dot driving.

[Explanation of symbols]

 A1 Energizing time of first shot Ae Energizing time of last dot B1 Brake pulse of first shot Be Brake pulse of last dot C1 Brake pulse timing of first shot Ce Brake pulse timing of last dot

Claims (2)

(57) [Claims] 1. A print wire is driven to form a dot with respect to the print medium, the drive control method for a wire dot print head for printing by a set of dots, single de not a predetermined period dot least front and back formation and <br/> Tsu drive for bets energizing pulse, after the energizing pulse of a drive for the last dot of the dot successive rows, the size of the pulses does not reach the print added respectively, and the continuous dot train The timing of the non-printing pulse added after the energizing pulse for driving the final dot and the timing of the non-printing pulse added after the energizing pulse for driving the single dot are different between the two.
Not drive control method of the print head and wherein the allowed. 2. A print wire is driven with respect to a print medium.
To form dots, and print by the set of dots.
Drive control method of wire dot type print head
hand, One-shot dots in which dots are not formed at least for a certain period before and after
Energizing pulse for driving the
After the energizing pulse for driving the last dot,
Each pulse of a size that cannot be reached is added, and Energizing pulse for driving the last dot of the continuous dot row
Timing of the pulse that does not lead to printing added after
Is added after the energizing pulse for driving the single dot.
Shorter than the timing of the pulse that does not
And a drive control method for the print head.