JPH02143866A - Printer apparatus - Google Patents

Abstract

PURPOSE:To raise the temperature of a printing head at the cold state in a short time by making an exciting coil conductive for warming when the temperature of said printing head detected by a thermistor does not reach a predetermined temperature, so that a magnetic flux is generated in the same direction as that of a permanent magnet constituted in said printing head. CONSTITUTION:The temperature of a printing head 1 is detected by a thermistor 19 provided within the head 1. When the temperature of the head 1 does not reach a predetermined temperature, a pulse signal is sent from a detecting circuit 28 through an IN port 26 and an OUT port 25 to a head driving circuit 27. The pulse signal is input to an input terminal of the circuit 27. When the pulse signal is input to the input terminal, a transistor is turned ON via a preamplifier, and a current flows in an exciting coil 16. As a result, a magnetic flux in the same direction as a magnetic flux 15 of the permanent magnet 14 is generated by the exciting coil 16, and the exciting coil 16 generates heat by Joule's heat and core loss while the armature 12 is maintained at a preparatory position for printing by the permanent magnet 14. Accordingly, owing to this control of warm-up running, the temperature of the printing head 1 is raised to the predetermined temperature, when the detecting circuit 28 judges that the printing operation is under control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a printer device such as a dot impact printer, and particularly to a printer device suitable for warm-up operation.

(Prior Art) A dot impact printer is equipped with a print head containing a plurality of print wires, and performs printing by protruding the necessary print wires from the print head. The protruding print wire contacts the paper via the ink ribbon.

This contact of the printing wire causes the ink of the ink ribbon to be applied onto the paper, forming dot characters.

By the way, when the print head is in a low temperature state, there is a problem that the ink of the ink ribbon that has flowed between the print wires becomes fixed, and the fixed ink deteriorates the operational performance of the print wires. Conventionally, when a print head is in a low temperature state, printing is forcibly started or a weak current that does not affect printing is passed through the print head to perform a warm-up operation.

However, if printing is forcibly started when the print head is in a low temperature state, the operational performance of the print wire will deteriorate as described above, resulting in deterioration in print quality such as spotting.

On the other hand, when performing warm-up operation, the current flowing through the print head must be set to a much lower value than during printing operation. This is because, for example, in a spring-charged print head, the magnetic flux of the permanent magnet is canceled by energizing the excitation coil and the printing wire protrudes, so the magnetic flux of the permanent magnet is not canceled during warm-up operation. This is because the excitation coil must be energized with a current of a certain degree, that is, a current of such a degree that the printing wire does not operate. Therefore, when warm-up operation is performed using such a weak current, there is a problem that it takes time to raise the temperature of the print head, and the waiting time from turning on the power to starting printing becomes longer.

(Problems to be Solved by the Invention) As described above, there has conventionally been a drawback that printing quality deteriorates at low temperatures. Additionally, in order to prevent this, when a configuration is adopted in which the temperature of the print head is increased during warm-up operation,
The drawback was that it was time consuming.

The present invention has been made in view of the above points, and provides a printer device that can raise the temperature of a print head in a low temperature state in a short time and can obtain high quality printing results even at low temperatures. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) That is, in the printer device according to the present invention, a spring-charged print head is provided with, for example, a thermistor, and the temperature detected by the thermistor does not reach a predetermined temperature. In this case, the excitation coil is energized to perform a warm-up operation so as to generate a magnetic flux in the same direction as the magnetic flux of the permanent magnet configured in the print head.

(Function) According to the above configuration, it is possible to energize the print head during warm-up operation without driving the print wire.

Therefore, the current value at that time can be increased,
As a result, the temperature of the print head, which is in a low temperature state, can be raised in a short time, and high quality printing results can be obtained even at low temperatures.

(Embodiment) Hereinafter, a printer device according to an embodiment of the present invention will be described with reference to the drawings.

First, the structure of the print head of this embodiment will be explained with reference to FIG.

FIG. 3 is a partially cutaway plan view showing the structure of the spring-charged print head 1, in which a print wire 1 is attached to one end.
A leaf spring 13 that urges the armature 12 to which 1 is attached toward the printing position, a permanent magnet I4 that holds (attracts) the armature 12 in the printing preparation position against the urging force of this leaf spring 13, and this permanent magnet The magnetic flux 15 is mainly composed of an excitation coil 1B for canceling the magnetic flux 15 of the magnetic flux 14.

In such a configuration, the permanent magnet 14 is connected to the yoke 17
, generates a magnetic flux 15 in the direction of arrow a in the magnetic circuit formed by the core 18, and the armature 12 is caused by the magnetic force.
is held (suctioned) in the print preparation position.

Here, when the excitation coil 18 is energized to generate a magnetic flux in the opposite direction to the magnetic flux 15 of the permanent magnet 14, the magnetic flux 15
is canceled, and the printing wire 11 attached to the armature 12 protrudes from the print head 1 toward the printing position by the biasing force of the leaf spring 13. That is, the leaf spring I3 is biased by the permanent magnet 14, and the excitation coil 18 is excited so as to generate a magnetic flux in a direction that cancels the magnetic field of the permanent magnet 14, so that the magnetic field of the permanent magnet is canceled and the bias is The leaf spring 13 in this state is released and the printing wire 11 is driven.

The printing wire 11 that protrudes in this manner comes into contact with a sheet of paper (not shown) via an ink ribbon (not shown). Due to this contact of the printing wire 11, the ink of the ink ribbon is applied to the paper, and dot characters are formed.

Further, this print head 1 is provided with a thermistor 19. This thermistor I9 is for detecting the temperature of the print head l.

FIG. 4 is a cross-sectional view of the print head 1 shown in FIG. 3 taken along the mV-mV line, and ink 20 of the ink ribbon flows between the print wires 11. This ink 20 has the property of solidifying when the printing ped 1 is in a low temperature state, which poses a problem of deteriorating the operational performance of the printing wire 11.

FIG. 1 is a block diagram showing the circuit configuration of the same embodiment,
A ROM 23, a RAM 24, an OUT port 25, and an IN port 26 are connected to the CPU 21, which controls the entire device, via a system bus 22.

The ROM 23 stores various data necessary for printing including programs. The RAM 24 stores data such as print data. The OUT port 25 controls signal output to the head drive circuit 27.

This head drive circuit 27 drives the print head 1 under the control of the CPU 21. IN boat 2B has detection circuit 2
Controls signal input from 8. This detection circuit 28 is
A detection signal from the thermistor 19 is input, and a determination is made as to whether warm-up operation control or printing operation control is to be performed.

FIG. 2 is a diagram showing a specific circuit configuration of the head drive circuit 27, in which reference numeral 31 indicates an input terminal for controlling printing operation, and 32
is an input terminal during warm-up operation control.

Connected to the input terminal 31 is a preamplifier 33 that turns on a transistor Ql connected to one end of the excitation coil 16 in the print head l and a transistor Q2 connected to the other end of the excitation coil 1B. In this case, when both transistors Ql and Q2 are turned on, a current flows in the excitation coil 181 using VD as a power source in the direction of arrow a',
A magnetic flux is generated in the opposite direction to the magnetic flux 15 of the permanent magnet 14 in the direction of arrow a shown in FIG.

On the other hand, the input terminal 32 is connected to a preamplifier 34 that turns on a transistor Q3 connected to the other end of the excitation coil 16 and a transistor Q4 connected to one end of the excitation coil IB. In this case, transistor Q
3 and Q4 are both turned on, a current flows in the excitation coil 16 in the direction of arrow b' using VD as the power source, and a magnetic flux is generated in the same direction as the magnetic flux 15 of the permanent magnet 14 in the direction of arrow a shown in FIG.

Next, the operation of this embodiment will be explained.

When the printer is powered on, the temperature of the print head 1 is detected by the thermistor 19 provided in the print head 1, and the detection signal is given to the detection circuit 28 shown in FIG. The detection circuit 28 determines whether warm-up operation control or printing operation control is to be performed by inputting this detection signal.

Here, for example, if the temperature of the print head l has not reached a predetermined temperature (preset temperature at which printing operation is possible), the detection circuit 28 determines that warm-up operation control is to be performed.

As a result, from the detection circuit 28 to the IN port 26 and the OUT
A pulse signal is sent to the head drive circuit 27 via the port 25 and input to the input terminal 32 shown in FIG.

When a pulse signal is input to the input terminal 32, the transistors Q3 and Q4 are turned on through the preamplifier 34, and a current flows to the exciting coil 16 in the direction of arrow b'. As a result, the magnetic flux 1 of the permanent magnet 4 in the direction of the arrow a shown in FIG.
Magnetic flux in the same direction as 5 is generated from the excitation coil 16, and with the armature 12 held (attracted) in the print preparation position by the permanent magnet 14, heat generation occurs in the excitation coil 1G due to Joule heat and iron loss. Due to this heat generation, the temperature of the print head 1 gradually increases, and the ink 20, which was stuck at low temperatures as shown in FIG. 4, also softens. In this way, until the temperature of the print head l reaches a predetermined temperature,
A pulse signal is applied to the input terminal 32, and warm-up operation control is executed.

On the other hand, as a result of this warm-up operation control, the temperature of the print head 1 increases and when it reaches a predetermined temperature, the detection circuit 28 determines that printing operation control is to be performed. Thereby, the pulse signal sent from the detection circuit 28 is input to the input terminal 31.

When a pulse signal is input to the input terminal 31, the transistor QI SQ2 is turned on through the preamplifier 33, and a current flows in the direction of arrow a' to the exciting coil 16, which is opposite to the magnetic flux 15 of the permanent magnet 14 in the direction of arrow a. magnetic flux is generated from the excitation coil 16. The generation of magnetic flux in the opposite direction cancels out the magnetic flux 15 of the permanent magnet 14. This results in
The armature 12 is released from the permanent magnet 14, and the printing wire 11 attached to the armature 12 is released from the leaf spring 1.
The urging force 3 causes the print head to protrude from the print head 1 toward the print position and print.

In this way, when the temperature of the print head l is low, by controlling the energization of the excitation coil 16 so that a magnetic flux in the same direction as the magnetic flux 15 of the permanent magnet 14 is generated, the print wire 11
It is possible to energize the print head 1 during warm-up operation without driving the print head 1 .

Therefore, the current value at that time can be made at least as high as that during printing operation, thereby increasing the amount of heat transferred per unit time to the ink 20 stuck between the printing wires 11 at low temperatures. Therefore, the time required for the ink 20 to soften to a state where printing can be performed can be shortened. Therefore, even at low temperatures, the temperature of the print head can be raised to the required temperature without requiring a long waiting time from turning on the power to starting printing, and high-quality printing results can be obtained.

[Effects of the Invention] As described above, according to the present invention, warm-up operation can be performed with a relatively high current, so the temperature of a print head that is in a low temperature state can be raised in a short time, and even in a low temperature state, the temperature of the print head can be increased. Quality printing results can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a circuit configuration according to an embodiment of the present invention, FIG. 2 is a diagram showing a specific configuration of the head drive circuit in FIG. 1, and FIG. FIG. 4 is a plan view showing the structure with a portion cut away, and FIG. 4 is a cross-sectional view of the print head shown in FIG. 3 taken along line IV--IV. 11... Printing wire, 12... Armature, 13
... Temporary spring, 14... Permanent magnet, 15... Magnetic flux,
16... Excitation coil, 17... Yoke, 18...
Core, 19... Thermistor, 20... Ink, 27
...Head drive circuit, 28...Detection circuit, 31 and 32...Input terminal, 33 and 34...Preamplifier, Ql-Q4...Transistor. Figure 1 Figure 2

Claims (1)

[Claims] By biasing a leaf spring to which a printing wire is attached via an armature by a permanent magnet, and energizing an excitation coil so as to generate a magnetic flux in a direction that cancels the magnetic field of the permanent magnet, the permanent A print head for a dot printer that drives the print wire by canceling the magnetic field of a magnet to release the biased leaf spring; a temperature detection means for detecting the temperature of the print head; and a temperature detection means for detecting the temperature of the print head. and energization control means for energizing the excitation coil so that magnetic flux in the same direction as the magnetic flux of the permanent magnet is generated when the temperature of the excitation coil has not reached a predetermined temperature.