JP2593933B2 - Dot impact printer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dot impact printer having improved durability against overload current and high temperature.

(Prior Art) A dot impact printer is generally widely used as an output means of a computer or the like. Further, the printing quality and durability are strongly affected by the heat capacity of the print head for performing printing, the current capacity of the power supply device for operating the printer, and the like.

An example of a print head of a conventional dot impact printer will be described.

FIG. 2 and FIG. 3 are configuration diagrams of the print head of the dot impact printer. In FIG. 2, a plurality of (for example, 24) wires 22 are provided on the end face 21 of the Punlit head so as to be able to protrude in order to perform printing.
These wires 22 are arranged, for example, in a staggered arrangement in two rows of 12 wires each. One end of each of the wires 22 is inserted through a plurality of (for example, 24) holes 23 formed in the end face 21 of the print head so as to freely project therefrom, and the other end is formed in a circular shape inside the print head. Are connected to a plurality of (for example, 24) electromagnetic control means 24 arranged in parallel.

As shown in FIG. 3, these electromagnetic control means 24 include, for example, a leaf spring 25, a permanent magnet 26, and an electromagnetic coil 27 in a spring charge type print head. Then, the leaf spring 25 is attracted by the magnetic force of the permanent magnet 26, and the magnetic force of the permanent magnet 26 is canceled when necessary by the magnetic force of the electromagnetic coil 27 to release the leaf spring 25, and the wire 22 protrudes by the elastic force of the leaf spring 25. It works to make it work.

In a printer having such a print head, heat is generated due to continuous energization of the electromagnetic coil 27. When heat is generated, the electromagnetic coil 27 is burned out, which adversely affects the life of the print head. Therefore, in order to reduce heat generation or the like during operation of the print head, the operation of the electromagnetic coil 27 of the print head is divided and performed. That is, when the temperature of the print head is high, for example, the operation of the even-numbered wires and the operation of the odd-numbered wires among the plurality of wires 22 are performed at different timings. As a result, the number of the electromagnetic control means 24 operating simultaneously is reduced, and the temperature rise of the print head is suppressed.

On the other hand, when other loads other than the print head operate at the same time, the power supply device that supplies a drive current to the electromagnetic coil 27 becomes overloaded. When the power supply device is overloaded, there is a possibility that the rectifier in the power supply device may be burned. Therefore, in order to reduce the overload of the power supply unit connected to the electromagnetic control unit 24 of the print head, even when the power supply unit is overloaded, by reducing the number of electromagnetic control units 24 that operate simultaneously in the same manner as described above, The current supplied by the power supply is reduced.

(Problems to be Solved by the Invention) However, the dot impact printer having the above configuration has the following problems.

That is, when the print head is hot and when the power supply device is overloaded, the same method is used. However, if the electromagnetic control means 24 separately arranged in the print head is operated simultaneously to improve heat dissipation at high temperatures, the load current may not be so small. Further, when the electromagnetic control means 24 disposed adjacent in the print head is operated in order to reduce the load current at the time of overload, heat dissipation may not be improved. Therefore, the temperature of the print head may exceed the heat capacity of the print head, or the current supplied by the power supply may exceed the current capacity of the power supply.

The present invention has been made in view of the above points, and it is possible to appropriately cope with a high temperature of the print head and an overload of the power supply device, and to improve the capabilities of both the print head and the power supply device. It is an object of the present invention to provide a dot impact printer capable of reliably preventing the operation exceeding the above operation and extending the life, reducing the price and improving the quality.

(Means for Solving the Problems) A dot impact printer according to the present invention includes a print head that performs printing by operating a plurality of wires by a plurality of electromagnetic control units, and an electromagnetic control unit corresponding to the plurality of wires of the print head. An operation control unit for selectively supplying a current to a specific plurality of electromagnetic control units to operate the wire; a temperature detection unit for detecting a temperature of the print head; and a driving current to the electromagnetic control unit. A power supply unit for supplying power and a current detection unit for detecting a load current of the power supply unit, wherein the operation control unit performs, when printing the print data, a temperature detected by the temperature detection unit when the detected temperature is equal to or higher than a predetermined temperature. Dividing the electromagnetic control means located at mutually dispersed positions into groups, supplying current in a time-division manner for each group, When the detected current of the means becomes equal to or more than a predetermined current, the electromagnetic control means located adjacent to each other are divided into groups, and the current is supplied in a time-division manner for each group.

(Operation) In the dot impact printer having the above configuration,
When the temperature detected by the temperature detecting means is higher than a predetermined temperature,
Current is supplied from the power supply to the electromagnetic control means distributed in the print head by the operation control means. As a result, heat generation in the print head is dispersed, and heat is effectively dissipated. Further, when the current detected by the current detecting means becomes equal to or more than a predetermined current, the current is selectively supplied from the power supply device to the electromagnetic control means arranged adjacent in the print head by the operation control means. Thereby, the load current supplied by the power supply device is reduced.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a dot impact printer according to the present invention.

The illustrated dot impact printer includes a print head 1 having a plurality of wires, a print head drive circuit 2 connected to the print head 1, and operation control means for controlling the operation of the print head 1 via the print head drive circuit 2. 3, a temperature detecting means 4 provided in the print head 1, a power supply device 5, and a current detecting means 6.

Here, the print head 1 has the same configuration as the above-described conventional print head including a plurality of wires and electromagnetic control means for controlling the protrusion of the plurality of wires, and a detailed description thereof will be omitted. I do.

The print head drive circuit 2 is for selectively supplying a current from the power supply device 5 to each electromagnetic control unit in the print head 1 in accordance with a signal input from the operation control unit 3. And the like.

The operation control means 3 is constituted by a CPU or the like, operates by receiving power supply from the power supply device 5, and outputs print data for causing the print head 1 to perform printing to the print head drive circuit 2. I do.

The temperature detecting means 4 is constituted by a thermistor or the like, and is fixed to a side surface of the print head 1. The temperature detecting means 4 operates by receiving power supply from the power supply device 5 and, when detecting that the temperature of the print head 1 has become equal to or higher than a predetermined temperature, sends a signal from the low level to the high level to the operation control means 3. Is output.

As is well known, for example, the power supply device 5 transforms a commercial power supply voltage to a predetermined voltage by a transformer, rectifies AC to DC by a rectifier, and supplies current to each load.

The current detecting means 6 is constituted by a voltage dividing network or the like built in the power supply device 5, and when detecting that the load current supplied by the power supply device 5 has become equal to or more than a predetermined current, the operation control means 3 A signal that changes from a low level to a high level is output.

FIG. 4 is a timing chart showing the operation of the dot impact printer of the present invention. In this figure, the horizontal axis indicates the passage of time. FIG. 4 (a) shows the time change of the high temperature detection signal output by the temperature detection means 4 of FIG. 1 as a high level signal or a low level signal. 4th
FIG. 6B shows a time change of the overload detection signal output from the current detection means 6 as a high level signal or a low level signal. 4 (c) to 4 (f) show time changes of print data output by the operation control means 3 in order to operate the wires of the print head 1 with the numbers (#) 1 to 24, respectively. FIGS. 5 and 6 are diagrams showing the operation state of the dot impact printer of the present invention.

Next, the operation of the dot impact printer configured as described above will be described.

First, the operation in a normal state will be described.
As shown in the period A of FIG. 4, when both the high temperature detection signal and the overload detection signal are at the low level, the operation control means 3 simultaneously outputs the print data corresponding to the wires of numbers 1 to 24.

On the other hand, when the power supply device 5 in FIG. 1 is in an overload state, that is, when the detection current of the current detection means 6 becomes equal to or more than a predetermined current, as shown in a period B in FIG. The overload detection signal goes high. At this time, the operation control means 3 sets the number 1 in the first period B1.
The print data corresponding to the 12 wires is output. Then, the operation control means 3 resets the print position of the print head 1 by a mechanism (not shown), and performs the next period B2.
Print data corresponding to the wires 13 to 24 is output. In this case, the electromagnetic control means for controlling the wires of numbers 1 to 12 are arranged adjacent to each other in the print head 1 as shown by hatching in FIG. And number 1
The electromagnetic control means for the wires Nos. .About.12 and the electromagnetic control means for the wires Nos. 13 to 24 form a group. In the above case, the number of simultaneous driving of the wires is halved compared to the normal operation, so that the magnitude of the current supplied to the print head 1 is 以下 or less of the normal state, The overload of the device 5 is more reliably reduced.

On the other hand, the operation when the print head 1 in FIG. 1 is in a high temperature state, that is, when the temperature detected by the temperature detecting means 4 is equal to or higher than a predetermined temperature will be described. As shown in a period C in FIG. When the overload detection signal is at the high level and the overload detection signal is at the low level, the operation control means 3 outputs print data corresponding to the wires of numbers 1 to 6 and 13 to 18 in the first period C1. Then, the operation control means 3 resets the print position of the print head 1 by a mechanism (not shown), and in the next period C2, numbers 7 to 7 are set.
The print data corresponding to the wires 12 and 19 to 24 is output. In this case, the electromagnetic control means for controlling the wires of numbers 1 to 6 and 13 to 18 are dispersedly arranged in the print head 1 as shown by hatching in FIG. A group is formed by a group of electromagnetic control means of the wires of numbers 1 to 6 and 13 to 18, and a group is formed by a group of electromagnetic control means of the wires of numbers 7 to 12 and 19 to 24. Therefore, heating of only one portion of the print head 1 is prevented from being promoted, and heat dissipation efficiency is improved. As a result, the temperature rise of the print head 1 is reliably reduced.

In addition, regarding the operation when the power supply device 5 in FIG. 1 is overloaded and the print head 1 is in a high temperature state, the print head data output by the operation control means 3 corresponds to the period B in FIG. Alternatively, an output as shown in any of C and C may be performed, or another split operation may be performed. That is, for example, print data corresponding to the wires of numbers 1 to 6 and 19 to 24 may be output first, and print data corresponding to the wires of numbers 7 to 18 may be output next.

The dot impact printer of the present invention is not limited to the above embodiment.

That is, in the above-described embodiment, the operation of the electromagnetic control means of the print head 1 is divided into two parts, but the present invention is not limited to this.
In consideration of the heat capacity of the power supply 6 and the current capacity of the power supply device 6, it may be divided into three or more.

(Effect of the Invention) The dot impact printer of the present invention having the above-described configuration is
Since the separate split operation method is adopted in the case of the high temperature state of the print head and in the case of the overload state, the following effects are obtained.

That is, in the high temperature state of the print head, the efficiency of heat dissipation of the print head can be improved, and the temperature rise can be suppressed more reliably.

Further, in the overload state of the power supply device, the current supplied to the print head can be divided and suppressed, and the overload of the power supply device can be more reliably reduced.

Therefore, the durability of the dot impact printer can be improved, the life can be extended, the price can be reduced, and the quality can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a dot impact printer according to the present invention, FIG. 2 is a configuration diagram of a print head, FIG. 3 is a configuration diagram of electromagnetic control means of the print head,
FIG. 4 is a timing chart showing the operation of the dot impact printer of the present invention, FIG. 5 is a diagram showing the operation state of the dot impact printer of the present invention at the time of overload, and FIG. 6 is the high temperature of the dot impact printer of the present invention. FIG. 6 is a diagram illustrating an operation state at the time. DESCRIPTION OF SYMBOLS 1 ... Print head, 2 ... Print head drive circuit, 3 ... Operation control means, 4 ... Temperature detection means, 5 ... Power supply device, 6 ... Current detection means.

Claims (1)

(57) [Claims] 1. A print head for performing printing by operating a plurality of wires by a plurality of electromagnetic control means, and a plurality of electromagnetic control means corresponding to a plurality of wires of the print head being selectively provided to a specific plurality of electromagnetic control means. An operation control unit that supplies a current to the wire to operate the wire; a temperature detection unit that detects a temperature of the print head; a power supply device that supplies a drive current to the electromagnetic control unit; and a load current of the power supply device. The operation control means, when printing the print data, when the temperature detected by the temperature detection means has become equal to or higher than a predetermined temperature, the electromagnetic control means disposed in the print head The electromagnetic control means at mutually dispersed positions are divided into groups, and current is supplied in a time-division manner for each group, and the current is supplied. When the detection current of the detection means is equal to or more than a predetermined current, the electromagnetic control means located at mutually adjacent positions among the electromagnetic control means arranged in the print head are divided into groups, and each group is divided into groups. A dot impact printer characterized by supplying current in a time-sharing manner.