JPS63209948A - Print head - Google Patents

Abstract

PURPOSE:To print a longitudinal line uniformly regardless of the curvature of a platen, by arranging pins such that the drive timing is different between pin groups having a wide gap and a narrow gap against the platen and the number of pins in wide gap group is smaller than that of the narrow gap group. CONSTITUTION:In a print head for a wire dot printer, the drive timing is different between upper/lower pins 11A in a pin group having a wide gap against a platen and central pins 11B in a pin group having a narrow gap, and respective pins are arranged such that the number of the upper/lower pins 11A is smaller than that of the central pins 11B. Consequently, when a longitudinal line or a combination of longitudinal lines is printed, drive timing of respective pin groups is shifted and the upper/lower pins 11A are less subjected to magnetic interference than the central pins 11B thus enabling uniform printing regardless of the curvature of the paten.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a method for creating a gap corresponding to the curvature of a platen when printing by driving a plurality of pins provided in a print head for a wire dot printer at a predetermined timing. The purpose was to solve the problem of wide pins causing poor tracking, and by making improvements to the pin arrangement, uniform printing was achieved regardless of the platen curvature. ing.

[Industrial application field]

The present invention relates to improvements in printheads for wire dot printers.

In wire dot printers, a plurality of pins arranged vertically within the print head are driven in a predetermined pattern as the print head moves along the platen, and the pins are moved forward toward the platen to print. ing. The pin is connected to an armature provided within the print head, and the pin is driven by energizing a coil provided within the print head to move the armature.

[Conventional technology]

The main structure of this type of wire dot printer is as shown in FIG. 2, where 1 is a platen and 2 is a print head. Inside the print head 2, a plurality of pins for printing are arranged such that their tips are vertically aligned.

An example of a conventional bin arrangement is shown in FIG. As is clear from the figure, the pins 3 are arranged in two rows in a staggered manner with a pitch p, and the interval between the left and right pin rows is np (where n is an integer other than O).
It becomes. The pins 3 in each row arranged in this way are
When the print head moves along the platen, it is driven at a predetermined timing to perform printing every time the print head moves by a distance p.

[Problem that the invention seeks to solve]

When printing vertical lines (or a set of vertical lines) using a print head with such a pin arrangement, the number of pins that are driven simultaneously (coil excitation) increases and magnetic interference increases, so the gap becomes wider corresponding to the platen curvature. The upper and lower pins cause tracking failure.

[Means for solving problems]

The present invention provides a print head that can solve the above-mentioned problems, and as a means for that purpose, in the present invention, a plurality of pins are driven at a predetermined timing and printed by moving them forward toward a platen. In the print head for a wire dot printer, the drive timing of each pin is different between a group with a wide gap and a group with a narrow gap to the platen,
However, the number of pins in the wide gap group is smaller than the number of pins in the narrow gap group.

[Effect]

Since the pins are arranged as described above, the magnetic interference during excitation of the upper and lower bins, which are groups with a wide gap between the platen and the platen, is less than when exciting the central bins, which are a group with a narrow gap between the platen and the platen. Therefore, the influence of platen curvature on pin followability is guaranteed.

〔Example〕

The invention will now be described in detail with reference to FIG.

FIG. 1 is an explanatory diagram of the pin arrangement of the print head according to the present invention.
In the figure, IIA is a group of upper and lower pins with a wide gap to the platen, and IIB is a group of central pins with a narrow gap to the platen. This figure shows an example of 24 bins, and the two upper and lower pins in each row are the upper and lower bins IIA, and the other pins are the center pins 11B. Generally, the number of upper and lower pins IIA is smaller than the number of central pins IIB. The upper and lower pins IIA are arranged in the left-right direction with respect to the center pin 11B as follows.

That is, the upper and lower pins 11A are arranged to be offset by a in the left-right direction (the direction of movement of the print head) with respect to the center pin IIB. This a is expressed by the following formula.

a= -X (2m+1) m is an integer Since the upper and lower pins IIA are arranged in this way, the drive timing (excitation timing) of the upper and lower pins IIA and the center pin IIB is 1/2 period (the print head is 1/2 2p movement time). For example, when printing a 100% duty pattern, each group of pins (upper and lower pins 11A).

The central pins IIB) are simultaneously excited, and the excitation timing is shifted by 1/2 cycle between each group.

Therefore, the upper and lower pins IIA receive magnetic interference for 8 bins, and the center pin IIB receives magnetic interference for 16 bins, and the degree of interference is greater in the center.

However, because the strokes of the upper and lower pins are longer than those of the central portion due to the platen curvature, the operating time is equalized.

Although FIG. 1 shows an example in which the upper and lower pins 11A of each row are shifted outward with respect to the center pin IIB, it goes without saying that the direction of this shift may be in either the left or right direction. .

In addition, in the above explanation, the excitation timing between each group is halved.
Although the example of shifting the period has been described, this shift does not have to be 1/2 period.

〔Effect of the invention〕

As described above, according to the present invention, the drive timing is different for the pins in the group with a wide gap to the platen (upper and lower pins) and the pins in the narrow group (center pins), and moreover, the number of upper and lower pins is in the center. When printing vertical lines (or a set of vertical lines), the driving timing of the pins in each group is shifted, and the magnetic interference received by the upper and lower pins is less than the magnetic interference received by the central pins. , it becomes possible to perform uniform printing regardless of the platen curvature.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the pin arrangement of a print head according to an embodiment of the present invention, Fig. 2 is a side view showing the main configuration of a wire dot printer, and Fig. 3 is an explanatory diagram of a conventional pin arrangement. A platen, 2 is a print head, 11A is an upper and lower pin (a group with a wide gap to the platen), and 11B is a center pin (a group with a narrow gap to a platen). Figure 1 is an explanatory diagram of the pin arrangement of the print head of the embodiment of this research.

Claims (1)

[Claims] In a print head for a wire dot printer that prints by driving a plurality of pins at predetermined timing and moving them forward toward a platen, each of the pins is divided into a group with a wide gap and a group with a narrow gap from the platen. The print head has different drive timings and is arranged such that the number of pins in the group with a wide gap is smaller than the number of pins in the group with a narrow gap.