JPH06171152A - Printing control device of serial imapct printer - Google Patents

Abstract

PURPOSE:To provide a means for controlling printing wire drive frequency of a serial impact dot printer by means of carriage moving speed. CONSTITUTION:A printing timing control/selection circuit selects corrected drive time by means of a selector 21 and a corrected drive time latch 22 based on detected speed data outputted from a speed detecting circuit. Reference drive time data and corrected drive time which are set beforehand by means of a main control means are added to an adder 23 to obtain printing timing data so that drive signals corresponding to detected speed and printing timing signals PTS are outputted to a drive circuit by counting control using a counter 24. As a result, drive time of a printing wire is set so as to avoid mechanical resonance frequency by means of a printing timing control means and a selecting means, and hence the behavior of the printing wire is controlled in a stabilized state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print wire control method for a serial impact printer.

[0002]

2. Description of the Related Art A serial type impact printer using a wire as a print head is widely used in a printer for printing characters or bit images in a dot matrix because of its excellent cost performance. The print wire is driven at a fixed set cycle, and the energization time to the print wire drive solenoid or the voltage application time to the print wire drive piezoelectric element during one cycle depends on the moving speed of the carriage equipped with the print head. It was fixed regardless.

[0003]

However, since the printing operation is performed by the print wire colliding with the printing paper via the ribbon without stopping while the carriage moves, the printing operation increases as the printing speed of the printer increases. The contact distance between the printing wire and the printing paper on the paper surface becomes long, the shape of the printed dots becomes large, and the printing quality is degraded. Further, this change in dot shape is clearly recognized as a change in character shape in one print line when printing is performed while the carriage is accelerating or decelerating, which is not preferable in print quality. In order to solve this problem, as a prior art, there is a method of continuously controlling the energizing time of the print wire according to the moving speed of the carriage. However, when printing is performed during acceleration or deceleration, a mechanical drive solenoid is used mechanically. There is a problem in that the behavior of the printing wire becomes unstable because it may be driven at different resonance points.

[0004]

SUMMARY OF THE INVENTION A print control device for a serial impact printer according to the present invention is a serial type printer using a wire for a print head, and a speed detecting means for detecting a moving speed of a carriage carrying the print head. And an energization time control means for receiving the output from the speed detecting means and outputting to the wire the urging time of the wire according to the moving speed of the carriage, and the movement of the carriage for receiving the output from the speed detecting means. A first feature, comprising a print timing control means for determining the drive frequency of the wire according to the speed to a preset value,
The print timing control means determines the moving speed of the carriage based on a first storage circuit that stores a reference driving time of the print head wire and a plurality of driving time data that is preset over the moving speed range of the carriage. A selection circuit for selecting the correction driving time data, a second memory circuit for temporarily storing the correction driving time data output from the selection circuit, data of the first memory circuit and data of the second memory circuit. The second feature is that it is composed of an adder for adding and a counter circuit for receiving output data of the adder and outputting the drive time of the print head wire by counting control.

[0005]

In the print control device of the serial impact printer according to the present invention, the energizing time control means makes the wire urging time longer when the carriage is slow and shortens the wire urging time when the carriage is faster. The print dot length can be made equal regardless of the moving speed of the print wire, and the print timing control means drives the print wire drive frequency away from the mechanical resonance point of the wire, so that the print wire behavior is stably controlled. It

[0006]

EXAMPLES The present invention will be described according to one example. FIG. 8 shows an external view of the impact printer of the embodiment. Reference numeral 1 is a head, 3 is printing paper, 4 is a platen, and 6 is a carriage. The head 1 is fixed to a carriage 6 and is connected to and driven by a motor 7 by a connecting member such as a timing belt 8. FIG. 6 shows a schematic view of the printing mechanism of the printer of the embodiment as seen from the moving direction of the carriage. Reference numeral 2 is an ink ribbon, and the printing wire 5 is driven in the direction of the arrow in the drawing, and printing is performed when the printing paper surface 3 collides.

FIG. 5 shows changes in drive current i and wire displacement x with time when a solenoid is used to drive the print wire. When the print wire 5 driven by the print command is selected and a drive current flows, a magnetic flux is generated in the magnetic circuit of the head, and the magnetic force drives the print wire toward the printing paper 3. When the printing wire 5 is displaced by driving and the tip of the printing wire 5 reaches the paper surface position through the ink ribbon 2, dots start to be formed on the printing paper 3, and the printing wire 5 enters the return operation and comes into contact with the printing paper 5 until it separates from the paper surface position. The printing wire 5 is in contact with the printing paper 3 during the period of time CT, and dots are formed on the printing paper surface. This contact time C
T depends on the energization time PW, and the longer the energization time, the longer the contact time CT.

FIG. 4B shows an ideal dot shape in the embodiment formed on the printing paper surface. When the cross section of the printing wire is circular and the diameter is D, when the carriage moves laterally by a distance L due to the contact time CT, the wire tip also moves a distance L on the paper surface, and the lateral dot length F of the dot formed is L + D. Become. Since the distance L changes depending on the carriage moving speed, the dot length F in the horizontal direction increases in proportion to the carriage moving speed as shown in FIG.

FIG. 7 shows the relationship between the drive frequency of the drive wire drive solenoid and the impact force on the printing paper surface. The impact force changes depending on the drive frequency, and the behavior of the print wire becomes unstable near the drive frequency where the impact force is small. In this unstable driving state, the resonance frequency f0 and its half, 1
It occurs strongly at a frequency of / 3. The drive of the print wire is fs which is the stable highest drive frequency avoiding those frequencies.
Done in.

When printing is performed during the acceleration or deceleration of the carriage as the printing speed increases, the printing timing signal is generated corresponding to the detected speed signal. Therefore, if the acceleration / deceleration printing section is long, the printing wire must be driven in the vicinity of the resonance frequency. In the present invention, control avoiding these unstable drive frequencies is performed.

FIG. 1 shows a block diagram of a control circuit of a printer according to the present invention. Main control means 1 including CPU
Print timing control of the reference drive time data and the corrected drive time data from 0 to the response frequency of the print head 1,
The print speed setting data corresponding to the printing operation is sent to the selection circuit 17, and is sent to the carriage control circuit 14, and the energization time is sent to the selection circuit 11 for controlling the energization time. The carriage control circuit 14 calculates the speed deviation from the speed data detected by the speed detection circuit 18 and the print speed setting data, outputs a drive signal for correcting the speed deviation to the carriage drive circuit 15, and causes the carriage system 16 to operate. Controls the motor. The print timing control / selection circuit 11 outputs a print timing signal PTS according to the print format to the drive time control / selection circuit 11 based on the detected speed data, preset reference drive time data, and corrected drive time data based on the detected speed. To do. The energization time control / selection circuit 11 inputs the print timing signal PTS, and outputs the drive time data PW to the print timing signal PW based on the preset reference energization time data and the corrected drive time data based on the detected speed.
Output to the head drive circuit 12 in synchronization with TS.

FIG. 2 shows a print timing control and selection circuit 17
The detailed example of is shown. The operation will be described with reference to the timing signal diagram of FIG. Reference drive time data is stored in advance in the reference drive time latch 20 from the main control means 10 by the selection signal line CS1, and a plurality of correction drive time data for drive time correction corresponding to the detected speed data is corrected and driven by the selection signal line CS3. Store in time latch 25. The speed data detected by the cycle measurement of the speed signal Vs input to the speed detection circuit 18 is input to the selector 21, and the selector 21 outputs the data corresponding to the detected speed from the plurality of previously set correction driving time data. select. The correction driving time data is stored in the correction driving time latch 22 by the selection signal line CS2.

The reference drive time data stored in the reference drive time latch 20 and the correction drive time data stored in the correction drive time latch 22 are added by the adder 23, and the print timing data corresponding to the detected speed is obtained. Is required. The print timing data is stored in the counter 24 as count data by the inverted signal of the speed signal Vs via the inverter 26. The counter 24 performs counting in units of clock pulses CLK and outputs a carry signal CY when the counting is completed. The carry signal CY becomes the print timing signal PTS and is output to the energization time control / selection circuit 11. After that, every time a speed signal is input, the drive time data corresponding to the detected speed is set by the detected speed data, and the wire drive solenoid is driven at the drive frequency corresponding to the carriage speed.

As shown in FIG. 3B, the printing wire drive frequency is set to a frequency at which the closest impact force corresponding to the moving speed of the carriage becomes maximum. When the moving speed of the carriage continuously increases as indicated by the one-dot chain line, the driving frequency of the section solenoid from the moving speed S1 to the moving speed S2 after the start of printing is f1, and the corresponding energization time PW1 is set. Similarly, the driving frequency is f in the section of the moving speeds S2 to S3.
2, the energization time is PW2, the driving frequency is f3 in the moving speed S3 to S4 section, the energization time is PW3, the driving frequency is the maximum driving frequency fs in the moving speed S4 to constant speed St section, and the driving time is the reference driving time. Becomes Figure 3
(A) of FIG. 11 shows a time-series change of the driving time. The driving time is shortened to 1 / f1, 1 / f2, and 1 / f3, and the energization time is shortened to PW1, PW2, and PW3 accordingly. When the carriage speed reaches the constant moving speed, the energization time becomes the reference driving time data of almost the highest response frequency.

In this embodiment, the print timing signal PTS and the detected speed signal have a one-to-one correspondence, but a print timing signal which is asynchronous with the detected speed signal is naturally generated depending on the print command.

[0016]

According to the print control method of the serial impact printer of the present invention, the drive timing of the print wire is set by the print timing control means and the selection means to avoid the mechanical resonance point of the drive solenoid. The print quality is improved because the behavior of the print wire is always controlled stably and the horizontal dot lengths of print dots can be made equal regardless of the moving speed of the carriage.

[Brief description of drawings]

FIG. 1 is a circuit configuration block diagram of an embodiment of the present invention.

FIG. 2 is a print timing control / selection circuit diagram according to an embodiment of the present invention.

3 is an explanatory diagram of signal timing of a print timing control and selection circuit of FIG.

FIG. 4 is a correlation diagram of a carriage speed and a print dot diameter according to the present invention.

FIG. 5 is a diagram illustrating a drive current and a wire displacement according to the embodiment of this invention.

FIG. 6 is a schematic diagram of a printer mechanism according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of frequency characteristics of the impact head according to the embodiment of the present invention.

FIG. 8 is an external view of an impact printer according to an embodiment of the present invention.

[Explanation of symbols]

 1 head 2 ink ribbon 3 printing paper 4 platen 5 printing wire 6 carriage 7 motor 8 timing belt 10 main control means 11 energizing time control and selection circuit 12 head drive circuit 14 carriage control circuit 15 carriage drive circuit 16 carriage system 17 print timing control , Selection circuit 18 speed detection circuit 20 reference drive time latch 21 selector 22 correction drive time latch 23 adder 24 counter 25 correction drive time latch 26 inverter 27 NOR gate

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display place

Claims (2)

[Claims] 1. A serial type printer using a wire as a print head, wherein the speed detection means detects a movement speed of a carriage having the print head, and the movement speed of the carriage receives an output from the speed detection means. The energization time control means for outputting to the wire the energizing time of the wire according to the above, and the drive frequency of the wire according to the moving speed of the carriage is set to a preset value in response to the output from the speed detecting means. A print control device for a serial impact printer, comprising: 2. The print timing control means according to claim 1, wherein a first storage circuit for storing a reference drive time of the print head wire, and a plurality of drive time data set in advance over a moving speed range of the carriage. A selection circuit for selecting correction driving time data according to the moving speed of the carriage, a second storage circuit for temporarily storing the correction driving time data output from the selection circuit, and a first storage circuit. 2. An adder for adding the data to the data of the second storage circuit, and a counter circuit for receiving the output data of the adder and outputting the drive time of the print head wire by counting control. Print control device for serial impact printer.