JPH0449477B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] A coil of a wire electromagnet, which is a wire dot printing head and is most frequently used when a temperature sensor is provided in the print head to prevent burnout due to heat generation of the electromagnet coil. By providing the temperature sensor in the print head, the structure of the print head can be simplified, the cost can be reduced, and highly reliable temperature detection can be achieved.

[Industrial application field]

The present invention relates to a wire dot printing head, and more particularly to a structure for arranging a temperature sensor to prevent coil burnout of a wire driving electromagnet.

There are various methods (attraction type, release type) for wire driving the wire dot print head, but in principle it is achieved by selectively exciting an electromagnet provided for each wire. However, excitation of the electromagnet is accompanied by heat generation, and there is a problem that, for example, when the electromagnet is driven continuously for a long time, the coil becomes hot and burns out. To counter this, you can either install a temperature sensor in the print head to monitor the temperature and stop printing when the temperature reaches an acceptable limit, or you can divide the wire into groups and use them in sequence, typically for one stroke. We are taking measures such as switching to split printing, which prints in multiple strokes. However, conventional methods have had problems with the arrangement structure of temperature sensors, and countermeasures have been an issue.

[Conventional technology]

Conventionally, a temperature sensor is provided for each electromagnet coil, or a single temperature sensor is provided on the outer surface of the print head casing or within the print head.

[Problem that the invention seeks to solve]

In the conventional structure described above, if a temperature sensor is provided for each coil, the temperature of each coil can be monitored, which is effective in preventing coil burnout, but it increases the cost and is difficult to miniaturize the print head. It is disadvantageous. On the other hand, the latter case, where only one temperature sensor is provided, is advantageous in terms of cost and miniaturization, but even though the coil temperature near the temperature sensor can be detected accurately, the coil temperature at a far position cannot be accurately detected. First, there is the problem of lack of reliability.

[Means for solving problems]

In order to solve the above-mentioned problems of the prior art, the present invention focuses on the fact that the wires of the printing head are used differently during printing, and provides temperature sensors corresponding to the electromagnets of the wires that are used frequently. It is a structure.

[Effect]

According to the above structure, the temperature of the coil that is used frequently, that is, tends to reach high temperatures, is monitored, so high reliability can be obtained. Further, since the number of frequently used wires is small, and therefore the number of temperature sensors is also small, it is advantageous in terms of cost and miniaturization.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of a wire dot printing head according to the present invention, A is a longitudinal sectional view thereof, and B is a B of A.
-B arrow view. This print head is of a 24-dot release type, and the wire W is provided at the tip of the leaf spring 1 arranged in an annular shape, and normally (in the non-driven state), the wire W is attached to the armature 2 provided at the center of the leaf spring 1.
is attracted to the core of the electromagnet M by the permanent magnet 3, and the leaf spring 1 is charged with elastic force. During printing, when the coil of the electromagnet M is excited and the magnetic force of the permanent magnet 3 is canceled out, the leaf spring 1
is released, and the wire W is driven by its elastic force to protrude from the wire guide 4 and perform printing.

FIG. 2 shows one row of the arrangement of the tips of the wires W (that is, the guide holes of the wire guide 4), and in the illustrated example, they are arranged in two rows in a staggered manner. In addition, the codes W1 to W
24 indicates the wire numbers; the left column has odd numbered wires W1, W3..., W21, W23, and the right column has even numbered wires W2, W4...,
W22 and W24 are lined up. In the case of such a wire arrangement, in order to prevent the wires from crossing each other, the electromagnet M is connected to the left half of the electromagnets M1, M3, ..., M21, M23 as shown in FIG. , W23, and the right half electromagnets M2, M4, ...,
M22, M24 are wires W2, W4..., W2
2. Used to drive W24.

Now, when printing alphabets, numbers, kana, and first-level kanji using the wire arrangement shown in Figure 2, the frequency of use of each wire W1 to W24 is as shown in Figure 3, and the frequency of use of wires W1 to W24 is as shown in Figure 3. Wire W7 is the highest, followed by No. 12 wire W12.
In addition, in the case of ruled line printing, the 12th wire W12 is used, so taking this into consideration, the 12th wire W1
It is also considered that wire No. 2 is used more frequently than wire No. 7 W7.

In other words, in the above wire arrangement, the electromagnets M7 and M of the 7th and 12th wires W7 and W12
Either or both of 12 will be at the highest temperature.
Therefore, as shown in FIG. 1, especially at B, the electromagnet M7
A temperature sensor S is provided near one or both coils of M12 and M12 to monitor the temperature of these coils. As a result, electromagnet M
7. When the coil temperature of M12 reaches the permissible limit, it is possible to prevent coil burnout by stopping printing or switching to divided printing as described above.

Note that the frequency of wire use varies depending on the number and arrangement of wires in the print head, as well as the printing mode.
The frequency of wire usage for each can be determined and the number and placement of temperature sensors can be determined based thereon. In this case, the number of wires that are used particularly frequently is at most 1 to 3, and therefore the number of temperature sensors can be very small.

〔Effect of the invention〕

As described above, according to the present invention, by providing a temperature sensor in the frequently used coil of a wire electromagnet, it is possible to reliably prevent coil burnout, and furthermore, because the number of temperature sensors is small, it is possible to reduce costs. Excellent effects such as advantages in terms of size reduction and miniaturization can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the wire dot printing head according to the present invention, FIG. 2 is a diagram of the wire tip arrangement,
FIG. 3 is a wire usage frequency diagram. W, W1 to W24...dot wire, M, M1
~24... Electromagnet, S... Temperature sensor, 1... Leaf spring, 2... Armature, 3... Permanent magnet, 4
...Wire guide.

Claims (1)

[Claims] 1. A wire dot printing head that drives a plurality of dot wires by selectively exciting an electromagnet provided for each wire, which is characterized by being equipped with a temperature sensor corresponding to the electromagnet of the wire that is frequently used. Head.