JPH03216348A - Wire dot printer - Google Patents

Abstract

PURPOSE:To always obtain an ideal printing quality by a method wherein a voltage to be applied to an electromagnetic coil constantly remains at a predetermined value, and a drive cycle in printing is changed in accordance with the fluctuation of a gap. CONSTITUTION:When a wire operation time Top1 is shorter than a wire operation time Top2 at the time of a normal printing gap by the amount of a shorter operation distance, Top1<Top2 is held. Therefore, by driving a wire at a drive cycle Tf1 shorter than a drive cycle Tf2 at a normal printing gap, a next printing action can be smoothly performed without the occurrence of a disturbance 5 in a wire displacing waveform by effectively using a rebound. On the other hand, when a wire operation time Top3 is longer than a wire operation time Top2 at the time of a normal printing gap by the amount of a longer operation distance, Top3>Top2 is held. Therefore, by driving a wire at a drive cycle Tf3 longer than a drive cycle Tf2 at a normal printing gap, the occurrence of a disturbance 5 in a wire diaplacing waveform is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application in Industry H] The present invention relates to a wire dot printer, and particularly to a wire dot printer equipped with a print head that can suitably handle long stroke printing.

[Conventional technology]

In conventional printers, as described in Japanese Utility Model Application Publication No. 63-63441, a lever position switch is used to change the voltage applied to the electromagnetic coil in accordance with changes in the printing gap to cope with long stroke printing.

[Problem to be solved by the invention]

In the above-described prior art, the voltage applied to the electromagnetic coil is higher than normal during long stroke printing. For this reason, a high-voltage power supply is required, and printers that print long strokes have had the problem of having to design a special dedicated power supply. Furthermore, in the conventional configuration, there was a problem in that the rebound after the collision between the armature and the core could not be used for the next operation in a timely manner during long stroke printing, and good printing quality could not always be obtained.

The purpose of the present invention is to solve the above-mentioned problems in the prior art,
An object of the present invention is to provide a wire dot printer that can always obtain good printing quality without changing the voltage applied to the electromagnetic coil. The voltage applied to the electromagnetic coil is always kept at a predetermined value, and the printing drive cycle is changed in accordance with fluctuations in the printing gap.

[Effect]

Depending on the variation of the printing gap, the printing drive cycle is set to be shorter than the drive cycle during normal printing when the printing gap is narrower than the gap during normal printing, and when the printing gap is wider than the gap during normal printing. By changing the drive cycle so that it is larger than the drive cycle during normal printing, it is possible to always print at the right time regardless of fluctuations in the printing gap.
The armature glue band can now be used effectively for the next printing operation, thereby ensuring consistently good printing quality.

〔Example〕

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

Figure 5 is a perspective view showing the structure of a wire dot printer. The print head 10 is mounted on a carrier 14, which is supported by two support rails for translational movement along the platen 13.

An ink ribbon 1 is placed between the print head 10 and the platen 13.
1 and paper 12 are loaded.

FIG. 6 is a sectional view showing the structure of the print head 10.

The wire 20 is connected to a spring 22 via a lever 29 and an armature 23. The yoke 24 is a permanent magnet 2
5 to the core 27, and the core 27 includes:
An electromagnetic coil 28 is attached. When no current flows through the electromagnetic coil 28, the armature 23 is attracted to the core 27 by the magnetic force of the permanent magnet 25, and as a result,
The spring 23 is deflected and strain energy is stored.

A canceling current is applied to the electromagnetic coil 28 and the permanent magnet 25
By nullifying the magnetic force of the spring 22, the stored energy of the spring 22 is released and the spring 22 flies forward. At this time, the wire 20 collides with the ink ribbon 11 and paper 12 to print one dot. Immediately before printing, by cutting off the current in the electromagnetic coil 28, the armature 23 is pulled back by the restored magnetic attraction force and the reaction force of the collision between the paper and the wire, collides with the column 727, and rebounds ( reband)
.

Next, the above printing operation will be explained in more detail using FIGS. 1 to 4, while comparing the present invention and the prior art. FIG. 1 is a diagram showing the wire operation waveform and current waveform according to the present invention, and FIG. 2 is a diagram showing the relationship between the printing gap and the wire driving period according to the present invention. The drive cycle can be changed according to changes in the printing gap. On the other hand, FIG. 3 is a diagram showing the wire operation waveform and current waveform according to the prior art, and FIG. 4 is a diagram showing the relationship between the printing gap and the wire drive period according to the prior art. In the prior art, the drive cycle is always kept constant regardless of variations in the printing gap. Figure 1(b) shows the normal printing gap (Gpaz)
The current 2 flowing through the electromagnetic coil 28 and the wire 2 at that time
0 operation 1 and band 4 are shown. FIG. 1(a) shows the current waveform 2 when the printing gap (Gpal) is narrow and the operation 1' of the wire 20 at that time. At this time, the wire operating time T o P 1 is the wire operating time T during the normal printing gap shown in FIG. 1(b). Since the operating distance is shorter than P2, it becomes faster and Top1<Tops.

Therefore, the drive period T x x during the normal printing gap
By driving with a shorter driving period T t 1, the 31i! The next printing operation can be performed smoothly by effectively utilizing the rebanding without causing irregularities 5 in the wire displacement waveform as shown in (a). Figure 1(c) shows the printing gap (Gp
Current waveform 2 when aa) is wide and wire operation waveform 1' at that time are shown. At this time, the wire operating time T o p δ is the wire operating time T o p z during the normal printing gap.
The longer the operating distance, the slower the TOPFI > TO
Therefore, by driving with a drive cycle TNδ longer than the drive cycle T z z during the normal printing gap, an irregularity 6 in the wire displacement waveform as shown in FIG. 3(c) of the prior art is caused. By effectively utilizing the reband 4, the next printing operation can be performed smoothly without any trouble.

In contrast, in the prior art, FIGS. 3 and 4
As shown in the figure, the normal printing gap (
The drive cycle T
1 = T t x. = T * a, the reband cannot be used effectively for the next wire operation, and as shown in Fig. 3(a), 5 is shown.
This results in irregularities in the wire displacement waveform as shown at 6 in FIG. 3(c).

Next, an embodiment of the means for changing the wire drive period in accordance with fluctuations in the printing gap will be described with reference to FIGS. 7 to 9.

As shown in FIG. 7 as a side view and FIG. 8 as a top view, a left side frame 42a and a right side frame 42b are fixed to the under frame 43, and the upper guide rail 33 and the upper and lower guides are fixed to these side frames. Rail 34 has been installed and purchased. The carrier 14 on which the print head 10 is placed can move in the B direction while being guided by the upper guide rail 33 and the lower guide rail 34. At this time, if the wire of the print head 10 is operated, the left side frame 42
The ink of the ink ribbon 11 can be transferred to the paper 12 on the platen 13 which is rotatably supported by the right side frame 42b and the right side frame 42b, that is, printing can be performed. The lower guide rail 34 is rotatable with respect to the left side frame 42a and the right side frame 42b,
Gear 35 is attached to the right end. However, the axis of the lower guide rail 34 is eccentric to the axis of the gear 35,
When the gear 35 rotates, the carrier 14 and print head 10 move in the A direction. As a result, the print head 10
The gap between the tip of the wire and the platen 13 is changed. The gear 35 is driven by a pinion 36 attached to the shaft of a stepping motor 44. A slit disk 37 is attached to the shaft of this stepping motor 44, and as the wire tip of the print head 10 moves, the slit disk 37 moves to the slit detection element 38.
It is designed to rotate against.

Next, the operation will be explained with reference to FIG. 9. First, the motor rotation command unit 50 generates a command to move the tip of the print head 10 in the direction of the platen 13.

Based on this command, the oscillator 70 starts, and the pulse generator 4
6 generates a pulse, and a stepping motor drive circuit 45
A stepping motor 44 of the printer mechanism is driven via the motor. The rotation of the stepping motor 44 is fed back as a pulse waveform by the slit disk 37 and the slit detection element 38. The pulse width 11 of this pulse is measured by the pulse width tzm constant section 48.

On the other hand, @tc of the pulse generated by the pulse generator 46
is measured by the pulse width tc determining section 47. The difference between these pulse widths tz tc = tn is determined by the step-out determination unit 49
Here, when the absolute value of t- exceeds a predetermined value, it is determined that synchronization has occurred.7 This determination result is sent to the motor rotation command unit 50, and as long as there is no synchronization , the motor rotation command unit 50 outputs a command to move the print head 10 in the direction of the platen 13, and when step-out is detected, the motor rotation command unit 50 outputs a command to move the print head 10 in the direction of the platen 13.
It is determined that the leading end of the print head 10 has come into contact with the upper surface of the paper 12 via the ink ribbon 11, and a command to rotate the print head 10 by a certain amount in the direction away from the platen 13 is output. In this way, the gap between the tip of the print head 10 and the top surface of the paper 12 can be kept constant regardless of the thickness of the paper 12.

Next, the operation of changing the printing drive period according to the gap variation will be described. The number of output pulses of the oscillator 70 is counted by the counter 60 to find the cumulative number of steps, and the cumulative number of steps is subtracted from the number of pulses at the full stroke from 61 to find the number of steps equivalent to the paper thickness, and the next conversion circuit is 62 to convert to paper thickness. In response to this paper thickness information, the gap command generation section 63 generates a gap command value according to the paper thickness and sends it to the speed command generation section 59. The speed command generation unit 59 generates a speed command value according to the gap command value so that when the gap is large, the printing speed is small, and when the gap is small, the printing speed is large. The signal is sent to the drive circuit 68. Since there is a reciprocal relationship between the printing drive cycle and the printing speed, a command signal is sent to the print head 69 and carrier motor 67 so that when the gap is large, the drive cycle is large, and when the gap is small, the drive cycle is small. It turns out. As a result,
The operation drive cycle of the print head and carrier. It can be changed according to changes in the gap.

〔Effect of the invention〕

According to the present invention, by configuring the printing driving cycle to be changed according to the fluctuation of the printing gap, it is possible to perform printing by effectively utilizing the adhesive band during printing in any printing gap, and even with any fluctuation in the printing gap. It also has the effect of always maintaining good printing quality.

[Brief explanation of drawings]

Figure 1 shows the wire displacement waveform and current waveform according to the present invention, and Figure 3 shows the conventional wire displacement waveform and current waveform.
(a) is a diagram showing a narrower printing gap, (c) is a diagram showing a wider printing gap, FIG. 2 is a diagram according to the present invention, and FIG. 5 is a perspective view of the printer, FIG. 6 is a sectional view of the print head, FIG. 7 is a side view for explaining the operation of the present invention, FIG. 8 is a top view thereof, and FIG. 9 is a block circuit for explaining the operation. It is a diagram. 10... Print head, 11... Ink ribbon, 12
... Paper, 13 ... Platen, 14 ... Carrier, 20 ... Wire, 22 ... Spring, 23 ... Armature, 25 ... Permanent magnet, 28 ... Electromagnetic coil, 29 ... Lever 37 ... Slit disk, 38
...Slit detection element ■ Younger brother 2 ■ Mi3 eyes'iz Gy (ra3 ””T,' ,,5)y,q
@． ．． ,7 Houzanwa 7th mouth

Claims (1)

[Claims] 1. Deflect the spring by attracting the armature attached between the wire and the spring with the magnetic force of the permanent magnet, and then undeflect the spring when the magnetic force of the permanent magnet is nullified by the magnetic force generated by the electromagnetic coil. A wire dot printer has a print head that prints with the tip of the wire using force, and paper and ink ribbon are loaded between the print head and the platen. A wire dot printer characterized by comprising means for changing a drive cycle.