JPH031956A - Printing head - Google Patents

Abstract

PURPOSE:To smooth the operation of a printing wire without being affected by the fluctuation of heating temp. by performing control so that the temp. of the printing head of a wire head printer is detected to allow the current corresponding to detection data to flow to an auxiliary coil in order to generate magnetic flux in the same direction as that of a permanent magnet in the auxiliary coil. CONSTITUTION:A printing head 15 is equipped with a temp. detecting means 12 detecting temp., an auxiliary coil 13 generating magnetic flux in the same direction as that of a permanent magnet 11 and a control part 14 allowing the current corresponding to the detection data of the temp. detecting means 12 to flow to the auxiliary coil 13. The control part 14 is constituted so that the detection signal of the temp. detecting means 12 is amplified by a sensor amplifier 16 and the analogue signal thereof is converted to a digital signal by an A/D converter circuit 17 and data is read from a table 18 storing data wherein the supply quantity of a current to the auxiliary coil 13 is preset with respect to detected temp. according to the digital signal from the A/D converter circuit 17 by a control circuit 19 and the supply quantity of a current is ordered to an auxiliary coil current supply circuit 20. Therefore, the current corresponding to the temp. rise of the printing head 15 flows to the auxiliary coil 13 and the magnetic flux in the same direction as that of the permanent magnet 11 is generated to increase attraction force.

Description

[Detailed Description of the Invention] [Summary] Regarding the structure of the print head of a wire dot printer, it has been found that printing can be performed at high speed and with high print quality without malfunction of the printing wire, which is not affected by fluctuations in heat generation temperature. The purpose is to attract the armature to the core of the printing magnet by the magnetic flux of the permanent magnet against the biasing force of the spring means, and by applying a current to the printing magnet that cancels the magnetic flux of the permanent magnet, the armature is moved by the restoring force of the spring means. Temperature detection means for detecting the temperature of the print head in a release type print head that releases the print head and prints using a print wire provided in the armature;
an auxiliary coil that generates magnetic flux in the same direction as the magnetic flux of the permanent magnet;
and a control section that causes a current to flow through the auxiliary coil in accordance with the detection information of the temperature detection means.

[Industrial application field]

The present invention relates to the structure of a print head for a wire dot printer.

2. Description of the Related Art In recent years, serial printers that print characters and the like using dots have come into widespread use in input/output terminals of data processing devices, word processors, and the like.

The print heads used in these blinks are required to have higher printing speed and higher printing quality.

(Prior Art) As shown in the side cross-sectional view of FIG. 2, the print head 1 has a plurality of print wires 3 guided by a wire guide 4 protruding from the center of the print head 1 arranged in a concentrated manner. It is configured to be driven by

The printing magnet 2 is formed by winding a coil 6 around a core 5, and an armature 7 is disposed in contact with the end face of the core 5.

The armature 7 is made of a magnetic material and is elastically fixed to the tip of a spring means (hereinafter referred to as a leaf spring) 8 so as to face the core 5, and a printing wire is connected to the tip of the spring means (hereinafter referred to as a leaf spring) via a holding part 9. 3 is fixed.

The magnet base 10a and the magnetic path section 10b have a permanent magnet 11 sandwiched between them, and a spacer 1 made of a magnetic material.
A magnetic path portion 10d is arranged across 0c, forming a loop-shaped magnetic path together with the core 5 and armature 7, and when the printing magnet 2 is not operating, the armature 7 is moved to the core by the magnetic force of the permanent magnet 11. 5 is adsorbed.

Here, when a current is applied to the coil 6 of the printing magnet 2 so that the NS pole of the permanent magnet 11 and the magnetic pole of the core 5 are opposite to each other, the core 5 acts to cancel the attractive force of the permanent magnet IT.

Then, the armature 7 springs upward in the figure due to the reaction force stored in the leaf spring 8, and the printing wire 3 simultaneously projects from the wire guide 4 to perform printing.

Printing is thus performed by selectively driving the plurality of printing magnets 2 within the print head 1.

[Problem to be solved by the invention]

Although the print head is constructed as described above, a considerable amount of heat is generated due to the energization of the coil.

Then, due to this heat, the area 10a, which is not shown by the two-dot chain line in Figure
The magnet base 10a curves outward as shown in FIG.

As a result, the amount of deflection of the leaf spring 8 increases by 8 degrees, as shown by the two-dot chain line, but this is partly due to the fact that the spring constant has been increased to meet the demand for higher speeds, and the restoring force of the leaf spring is affected by the permanent magnet. There was a problem in that the suction force could not be resisted, resulting in failure of the printing wire 3 to restore or follow up.

That is, as shown in the diagram of FIG. 4, the restoring force of the leaf spring 7 under normal conditions is determined by reducing the gap between the core 5 and the armature 7, as shown by the one-dot chain line, and the restoring force of the leaf spring 7 as shown by the solid line. 11
It is set so that it is within the range of suction power.

However, as described above, when the amount of deflection of the leaf spring 7 increases due to thermal deformation, the restoring force of the leaf spring 7 no longer falls within the range of the attractive force of the permanent magnet 11, as shown by the two-dot chain line.

An object of the present invention is to enable high-speed, high-quality printing without being affected by fluctuations in heat generation temperature and causing no malfunction of the printing wire.

[Means to solve the problem]

As shown in the side cross-sectional view of FIG. 1(a), the temperature detection means 12 detects the temperature of the print head, the auxiliary coil 13 generates a magnetic flux in the same direction as the magnetic flux of the permanent magnet 11, and the temperature detection means 12 detects the temperature. The control unit 14 includes a control unit 14 that causes a current corresponding to the information to flow through the auxiliary coil 13.

[Effect]

When the print head generates heat, the heat is detected by the temperature detection means 12, and the control unit 14 causes a current corresponding to the detected information to flow through the auxiliary coil 13, thereby generating a magnetic flux in the same direction as the magnetic flux of the permanent magnet 11. , the attraction force to the armature 7 increases against the bias of the temporary spring 8.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

Identical parts are designated by the same reference numerals throughout the figures.

As shown in the side sectional view of FIG. 1(a), the print head 15 of the present invention includes a temperature detection means 12 such as a thermistor for detecting the temperature of the print head 15, and a magnetic flux in the same direction as the magnetic flux of the permanent magnet 11. The control section 14 includes an auxiliary coil 13 that generates the temperature, and a control section 14 that causes a current to flow through the auxiliary coil 13 in accordance with the information detected by the temperature detection means 12.

That is, A-A in the figure (a) shown in the same figure and in the same figure (b)
As shown in the cross-sectional view, the auxiliary coils 13 are further individually wound on the individual coils 6 wound around the core 5, and the auxiliary coils 13 are connected in series.

On the other hand, the control unit 14 includes a sensor amplifier 16 that amplifies the detection signal of the temperature detection means 12, and an A/D conversion circuit 17 that converts the analog signal of the sensor amplifier 116 into a digital signal.
, a table 18 that stores data in which the amount of current applied to the auxiliary coil 13 is set in advance with respect to the detected temperature, and an A/D
Table 1 depends on the digital signal from the conversion circuit L7.
8 data is read out and the energization amount is determined from the auxiliary coil energization circuit 20.
It is composed of a control circuit 19 that instructs.

Therefore, a current corresponding to the temperature rise of the print head 15 flows through the auxiliary coil 13 by the control unit 14, and the permanent magnet 11
generates a magnetic flux in the same direction as the magnetic flux of , increasing the attractive force of the permanent magnet 11 as shown by the dotted line in FIG.

As a result, even if the gap between the core 5 and the armature 7 increases due to thermal deformation and the amount of deflection of the leaf spring 8 increases,
The armature 7 securely holds the core 7 against the bias of the leaf spring 8.
The paper will be attracted to the paper, and the printing operation will be reliable.

〔Effect of the invention〕

With the print head of the present invention, even if the gap between the core and the armature increases due to thermal deformation and the amount of deflection of the temporary spring increases, the armature will be reliably attracted to the core for a long time, allowing printing. It has great industrial effects, such as reliable operation.

[Brief explanation of the drawing]

FIG. 1(a) is a side sectional view of the print head of the present invention, FIG. 1(b) is a sectional view taken along line A-A in FIG. 1(a), and FIG. 2 is a side sectional view of a conventional printing head. , Figure 3 is an enlarged side view of the main part of Figure 2, Figure 4 shows the attraction force of the permanent magnet, the restoring force of the leaf spring, and the core.
FIG. 3 is a diagram showing the relationship between armature gap dimensions. In the figure, 1.15 is the print head, 2 is the print magnet, 3 is the print wire, 4 is the wire guide, 5 is the core,
6 is the coil, 7 is the armature, 8
is a spring means (plate spring), 9 is a holding part, 10a
is the magnet base, 10b is the magnetic path section, 10c
is a spacer, 10d is a magnetic path section, 11 is a permanent magnet, 12 is a temperature detection means, 13 is an auxiliary coil, I4 is a control section, 17 is an A/D conversion circuit, 16 is a sensor amplifier, 18 is a table, 19 is a control The circuit 20 is an auxiliary coil energizing circuit. Below, Ahead of the invention] Sectional view (α) Tatsumi 1 ('t 1) Nanami's [9th knife, press and hold section 1 Kidney diagram Figure 2 Front part of Figure 2] Hongdae Detective 1 Δ-face mouth sugar times Same figure (0,) A-A face figure (b) Figure F (2 of 1,000) Shows the relationship between the core... and Mayuyu's decoration ■ Figure diagram

Claims (1)

[Claims] The armature (7) is attracted to the core (5) of the printing magnet (2) by the magnetic flux of the permanent magnet (11) against the bias of the spring means (8), and the printing magnet ( 2) by passing a current through the permanent magnet (11) to cancel the magnetic flux of the permanent magnet (11).
In a release-type print head that releases the armature (7) with a restoring force and prints using a print wire provided in the armature (7), temperature detection means (12) for detecting the temperature of the print head; , an auxiliary coil (13) that generates a magnetic flux in the same direction as the magnetic flux of the permanent magnet (11), and a control section (14) that causes a current corresponding to the detection information of the temperature detection means (12) to flow through the auxiliary coil (13). ).