JPH06227007A - Electromagnetic print head - Google Patents

Abstract

PURPOSE:To provide an electromagnetic printing head which can easily monitor as a whole elevation of temp. of a plurality of arranged electromagnetic coils in relating to the electromagnetic printing head wherein a printing wire is driven by means of the electromagnetic coils. CONSTITUTION:The title printing head is constituted by providing a plurality of printing wires 6 each arranged by facing its apex to a printing part movably back and forth in the axial line direction, a plurality of electromagnetic coils 3 arranged for driving a plurality of printing wires 6 independently in each printing wire 6 in each axial line direction, a good heat-conductive member 11 arranged so as to be brought into contact with a plurality of the electromagnetic coils 3 and a thermister 20 arranged to detect temp. of the good heat- conductive member 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic print head in which a print wire is driven by an electromagnetic coil.

In the case of an electromagnetic print head, the electromagnetic coil heats up, but if the temperature exceeds the limit, there is a risk of electrical short accidents due to deterioration of the coil wire coating. Therefore, it is necessary to constantly monitor the temperature rise of the electromagnetic coil.

[0003]

2. Description of the Related Art In a print head, a plurality of (for example, 24) print wires are arranged, and a plurality of electromagnetic coils for individually driving the print wires are formed in a circular shape. It is arranged.

The thermistor for detecting the temperature of the electromagnetic coil is arranged so as to come into contact with one or two of the plurality of electromagnetic coils arranged in a circle.

[0005]

However, if the thermistor is in contact with only one or two electromagnetic coils, the temperature rise of the remaining electromagnetic coils cannot be monitored. Therefore, when the temperature of the remaining electromagnetic coils rises abnormally, a failure such as burning of the coils is inevitable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electromagnetic print head which can easily monitor the temperature rise of a plurality of arranged electromagnetic coils.

[0007]

In order to achieve the above-mentioned object, an electromagnetic print head of the present invention has an axial line with its tip end facing the print portion, as shown in FIG. 1 for explaining the embodiment. A plurality of printing wires 6 arranged so as to be able to move forward and backward
And a plurality of electromagnetic coils 3 arranged to drive the plurality of printing wires 6 independently in the respective axial directions of the respective printing wires 6, and the plurality of electromagnetic coils 3 are arranged so as to be in contact with the plurality of electromagnetic coils 3. Good heat transfer member 11 and good heat transfer member 1
The thermistor 20 arranged so as to detect the temperature of 1 is provided.

In the electromagnetic print head of the present invention, a plurality of print wires 6 are arranged so that each of the print wires 6 can be moved back and forth in the axial direction with the tip end facing the print portion, and the plurality of print wires 6 are provided for each print wire 6. From the thermistor 20, a plurality of electromagnetic coils 3 independently arranged to drive in the axial direction, a thermistor 20 arranged to contact at least one of the plurality of electromagnetic coils 3, and the thermistor 20. The lead wire 21 is provided so as to extend and contact the plurality of electromagnetic coils 3.

Further, in the electromagnetic print head of the present invention, a plurality of print wires 6 are arranged so that each of the print wires 6 can be moved back and forth in the axial direction with the tip end facing the print portion, and the plurality of print wires 6 are connected to each print wire 6. Each of the plurality of electromagnetic coils 3 arranged to be independently driven in the axial direction and the two adjacent electromagnetic coils 3 of the plurality of electromagnetic coils 3 are in contact with each other. A plurality of thermistors 20 are arranged between the electromagnetic coils 3 so as to be sandwiched between them.

[0010]

When any one of the plurality of electromagnetic coils 3 has an abnormal temperature rise, the heat is transferred to the good heat transfer member 11 or the lead wire 21 which is in contact with the electromagnetic coil 3, and the temperature thereof is changed. It is detected by the thermistor 20.

When the thermistors 20 are arranged so as to be sandwiched between every other electromagnetic coil 3, the thermistor 20 directly contacts each electromagnetic coil 3. Therefore, when there is an abnormal temperature rise in any of the plurality of electromagnetic coils 3, the temperature is directly detected by the thermistor 20 in contact with the electromagnetic coil 3.

[0012]

Embodiments will be described with reference to the drawings. 1 and 2 show a first embodiment of the present invention applied to an electromagnetic release type print head.
In this embodiment, a yoke 2 made of a magnetic material for forming a magnetic circuit is arranged so as to be in close contact with both sides of the permanent magnet 1 which are magnetic poles.

A portion 2 of the yoke 2 that sandwiches the permanent magnet 1.
A and 2b are formed in a continuous cross-sectional shape according to the shape of the permanent magnet 1. Then, the tip portion 2c of the yoke 2 connected to the S pole side of the permanent magnet 1 is formed by dividing it into six at equal intervals as shown in FIG.

The electromagnetic coil 3 is wound around the front side portions 2c of the yokes 6 arranged side by side to form a so-called iron core. Therefore, hereinafter, this portion is referred to as the iron core 2c.
A magnetic circuit through which the magnetic flux of the permanent magnet 1 flows is formed for each iron core 2c. Therefore, in this embodiment, six magnetic circuits are formed side by side.

An armature (movable member) 4 made of a magnetic material is arranged so as to face the iron cores 2c arranged straight in 6 rows. A base end portion of a print wire 6 is fixed to the tip end side of the armature 4 via a beam 5.

The six printing wires 6 are arranged side by side, with their tips 6a directed toward the printing portion and guided so as to be able to move back and forth in the axial direction. Each armature 4 has a leaf spring 8 attached to the yoke 2a on the N pole side of the permanent magnet 1 in series.
Is fixed to the free end of the iron core 2 and is arranged so as to be able to move toward and away from the end surface of the iron core 2c when the leaf spring 8 bends.

In the natural state, the leaf spring 8 is almost straight,
There is a gap between the armature 4 and the iron core 2c. However, since the magnetic flux of the permanent magnet 1 passes through the magnetic circuit, the armature 4 elastically deforms the leaf spring 8 by the magnetic force in the standby state to attract the iron core 2c, and strain energy is stored in the leaf spring 8. It is in the state where it was opened.

The base end side of the leaf spring 8 is superposed on the yoke 2 and the permanent magnet 1, and is screwed and fixed to a base 10 made of a non-magnetic material such as an aluminum alloy.

A current is applied to the electromagnetic coil 3 wound around each iron core 2c so that an electromagnetic force is generated in a direction to cancel the magnetic force of the permanent magnet 1. When a current is passed from the drive circuit to the electromagnetic coil 3 according to a control signal from a print control unit (not shown), the magnetic force of the permanent magnet 1 is canceled in the magnetic circuit.

Then, the armature 4 is moved by the restoring force of the leaf spring 8 in the direction away from the iron core 2c, whereby the tip of the printing wire 6 is moved in the protruding direction. In this way, each print wire 6 is independently driven for each print wire 6 by the electromagnetic coil 3, and the recording paper is struck via an ink ribbon (not shown) to perform wire dot printing.

A good heat transfer member 11 made of, for example, an aluminum alloy plate is fixed so as to contact the six electromagnetic coils 3 arranged in a straight line. The thermistor 20 is arranged so as to contact the surface on the opposite side of the good heat transfer member 11.

As a result, the heat generated from each electromagnetic coil 3 is conducted to the good heat transfer member 11, and the temperature is detected by the thermistor 20. Therefore, when any of the six electromagnetic coils 3 has an abnormal temperature rise, the heat is immediately transmitted to the good heat transfer member 11 and the temperature is detected by the thermistor 20, and any one of the electromagnetic coils 3 is detected.
It is determined in the control unit (not shown) that the temperature of exceeds the limit value. Then, for example, control is performed to decrease the printing speed and reduce the amount of heat generation.

3 and 4 show a second embodiment of the present invention, in which the thermistor 20 is brought into direct contact with at least one electromagnetic coil 3 (two electromagnetic coils 3 in this example), and the thermistor 20 is also provided. The lead wires 21 extending from both sides are respectively brought into contact with the remaining plural electromagnetic coils 3.

Even with such a configuration, the heat generated by all the electromagnetic coils 3 is transmitted to the thermistor 20 directly or via the lead wire 21 to obtain the same effect as that of the first embodiment. You can

FIGS. 5 and 6 show a third embodiment of the present invention, in which every two adjacent electromagnetic coils 3 are contacted with each other so that every two adjacent electromagnetic coils 3 are in contact with each other. The thermistor 20 is arranged so as to vertically sandwich the thermistor 20.

As a result, the three thermistors 20 are in contact with the two electromagnetic coils 3, and the temperature of each electromagnetic coil 3 can be directly detected by any of the thermistors 20.

Further, each thermistor 20 includes an electromagnetic coil 3
Since it is inserted vertically between the electromagnetic coils and sandwiched between the electromagnetic coils 3, the temperature change of the electromagnetic coils 3 can be detected at a high reaction speed.

7 and 8 show an application example of the present invention, in which the thermistor 20 is arranged so as to be in contact with the two central electromagnetic coils 3. It should be noted that the present invention is not limited to the above-described embodiment, and can be applied to various electromagnetic print heads, not limited to the electromagnetic release type, for example.

[0029]

According to the electromagnetic print head of the present invention, the temperature rise of any of the plurality of arranged electromagnetic coils is detected by the thermistor, so that the temperature of the entire electromagnetic coil can be easily monitored. It has an excellent effect of preventing burning of the electromagnetic coil in advance.

[Brief description of drawings]

FIG. 1 is a side view of a first embodiment.

FIG. 2 is a sectional view taken along line II-II of the first embodiment.

FIG. 3 is a side view of the second embodiment.

FIG. 4 is a sectional view taken along line IV-IV of the second embodiment.

FIG. 5 is a side view of the third embodiment.

FIG. 6 is a sectional view taken along line VI-VI of the third embodiment.

FIG. 7 is a side view of an application example of the present invention.

FIG. 8 is a sectional view taken along line VIII-VIII of an application example of the present invention.

[Explanation of symbols]

 3 Electromagnetic coil 6 Printing wire 11 Good heat transfer member 20 Thermistor

Claims (3)

[Claims] 1. A plurality of printing wires (6) arranged so as to be able to advance and retreat in the axial direction with their tips toward the printing unit, and the plurality of printing wires (6) are independent for each printing wire (6). A plurality of electromagnetic coils (3) arranged to drive each in the axial direction, a good heat transfer member (11) arranged so as to contact the plurality of electromagnetic coils (3), and a good heat transfer An electromagnetic print head comprising: a thermistor (20) arranged to detect the temperature of the member (11). 2. A plurality of printing wires (6) arranged so as to be capable of advancing and retreating in the axial direction with their tips toward the printing section, and the plurality of printing wires (6) are independently provided for each printing wire (6). A plurality of electromagnetic coils (3) arranged to be driven in the axial direction, and a thermistor (20) arranged so as to contact at least one of the plurality of electromagnetic coils (3), An electromagnetic print head comprising: a thermistor (20); and a lead wire (21) arranged so as to contact the plurality of electromagnetic coils (3). 3. A plurality of printing wires (6) arranged so as to be able to advance and retreat in the axial direction with their tips toward the printing section, and the plurality of printing wires (6) are independent for each printing wire (6). A plurality of electromagnetic coils (3) arranged to drive each in the axial direction, and two adjacent electromagnetic coils (3) of the plurality of electromagnetic coils (3) are contacted with each other. An electromagnetic print head comprising a plurality of thermistors (20) sandwiched between every other plurality of electromagnetic coils (3).