JPH0331351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer that is capable of restarting printing in a short time by continuously driving the printer and cooling the print head when it generates heat.

Conventionally, when a printer is continuously driven, the print head generates heat, and in particular, printers using a print head using a plunger or the like have had drawbacks such as a decrease in magnetic flux due to the heat generation and a weakening of the impact force.

In view of this, the present invention temporarily interrupts printing when the temperature exceeds a predetermined temperature and retracts the printing head in front of a cooling device, thereby shortening the cooling time and maintaining printing quality.

A detailed description will be given below with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment of the present invention.

FIG. 2 is its block diagram. In FIGS. 1 and 2, reference numeral 1 denotes a printing head, and a plunger-type dot head is shown as an example, but it goes without saying that a clapper-type head or a thermal head may also be used. 2 is an ink ribbon cartridge; 3 is a platen; 4 is a ribbon cable for transmitting signals to the print head 1; 5 supports the print head 1 and the ink ribbon cartridge 2; The carrier 7, which slides from side to side, is a temperature detection device for detecting the temperature of the print head 1, and is comprised of a sensor 8 and a detector 9, which outputs at least two levels of detection signals depending on the temperature detected by the sensor. It is configured.

Reference numeral 10 is a wire for moving the carrier 5, the end of which is fixed to the carrier 5, and is spanned between two pulleys 11, 12. 13
16 is a cooling device; 17 is a memory for storing the current position when the print head 1 is evacuated; and 18 is a driver for the print head 1. It is a circuit. Next, the operation of the present invention will be explained.

First, during normal printing, ribbon cable 4
Of course, printing is performed according to the signals transmitted through the printer, but if high-speed printing continues for a long time, the print head 1 will generate heat, and especially in the print head 1 that uses ferrite magnets, magnetic flux will increase. This causes problems such as deterioration of print quality and typographical errors. Therefore, the temperature of the print head is detected by the temperature detection device 7, and temperature detection signals of at least two levels are sent out. In this embodiment, the first level is output when the temperature is less than 75° C. and is input to the driver circuit 18. At this time, the driver circuit 18 operates the print head 1 at high speed.

Eventually, the temperature of print head 1 rises to 75℃~
When the temperature reaches 94° C., a second level signal is sent from the temperature detection device 7 and inputted to the driver circuit 18.

Therefore, the driver circuit 18 is connected to the print head 1.
Switch the drive speed to low speed.

When the temperature of the print head 1 further increases, the temperature detection device 7 either stops outputting a signal or sends out a signal at a third level, and the driver circuit 18 stops driving and changes the position of the print head 1 at that time. is stored in the memory 17.

Further, the motor 14 is rotated in reverse (or forward) by the drive circuit 15 to move the print head 1 to the front of the cooling device 16.

Therefore, the print head 1 is cooled within a short time by the cooling device 16.

Eventually, when the temperature of the print head 1 drops to the level 2, the motor 14 is rotated forward (or reversed),
The print head 1 is returned to the previously memorized position and printing is restarted at a low speed.

Furthermore, when the temperature drops to level 1, the driver circuit 18 drives the print head 1 at high speed.

Now, these operations will be further explained with reference to the time chart shown in FIG. Here, the driver circuit 18 in FIG. 2, the drive circuit 15 constituting the spacing mechanism 13, and the memory 17 are connected to an input/output bus line of a control device (not shown), and are operated by commands from this control device. This part uses well-known technology.

First, in FIG. 3, A is a clock pulse output from the control device and input to the driver circuit 18, B, C, and D are print head temperature levels 1 and 2 output from the temperature detection device 7, respectively.
2 and 3, E is a head drive pulse that is divided or stopped by the driver circuit 18 based on the clock pulse input to the driver circuit 18 and the temperature levels 1, 2, and 3 of the print head; Input level 2, level 3
These are signal waveforms respectively indicating the temperature level of the motor and the motor drive voltage for driving the motor according to commands from the input/output bus line of the control device.
Further, it is assumed that the switching of the printing speed for temperature levels 1 to 3 is performed for each printing line. and,
Normally, the control device determines the print character pitch and print mode from the print data and control data input from the external device, outputs a clock pulse corresponding to the print speed, and also determines the spacing direction and the number of print digits. It is calculated and output to the drive circuit 15 together with the print data. Driver circuit 18
At level 1, the head drive pulse is controlled at a 1:1 ratio with the clock pulse at high speed, and at level 2, the frequency is divided 1:2 to control low speed printing. Therefore, at this time, the print dot data input from the control device through the input/output bus line is output to the print head 1 in synchronization with the head drive pulse. The drive circuit 15 refers to the printing speed, printing direction, and number of printing digits set by the control device, and controls the specified printing speed when the printing speed is at level 1 (in this embodiment, when it is not level 2 or level 3), At level 2,
Low speed (half speed in this embodiment) printing speed control is performed.

In this embodiment, the temperature levels 1 to 3 of the print head are connected to the driver circuit 18 and the drive circuit 15, but the print speed, printing direction, and number of printing digits are set in the drive circuit 15, and the external This is because the configuration is controlled by a circuit, which reduces the processing time load on the control device after printing starts, and allows the control device to perform reception processing and data editing processing, which reduces the processing capacity of the control device. Then, the temperature level of the print head is detected by the control device,
It does not depart from the present invention even if all processing is controlled by this control device.

As explained in detail above, according to the present invention,
High-speed printing is performed when the temperature detection signal is at the first level according to at least two levels of temperature detection signals;
At the second level, low-speed printing is performed, and when the temperature detection signal is not detected or at the third level, printing is temporarily interrupted and the print head is retracted in front of the cooling fan to cool the print head in a short time. Since printing is restarted when the temperature has decreased to the second level, printing with stable printing quality is possible, and the cooling time can be shortened.

In the above embodiment, the print head operates in three stages depending on the temperature, but when the temperature exceeds a predetermined temperature, it immediately stops printing, moves to the front of the cooling device, and when it cools down to a predetermined temperature, it stops printing. It goes without saying that restarting may be a good idea.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the present invention, Fig. 2 is a perspective view showing one embodiment of the present invention;
The figure is a block diagram thereof, and FIG. 3 is a time chart showing signal waveforms at various parts in the block diagram of FIG. DESCRIPTION OF SYMBOLS 1... Print head, 5... Carrier, 7... Temperature detection device, 13... Spacing mechanism, 14... Motor,
15...Drive circuit, 16...Cooling device, 17...Memory, 18...Driver circuit.

Claims (1)

[Claims] 1 a temperature sensing device for sensing the temperature of the print head at at least two levels; a cooling device fixed in place for cooling the print head; and a temperature sensing device for detecting the temperature of the print head at a first level; a driver circuit that drives the print head at a low speed when at a second level and stops the print head when there is no signal or at a third level; a storage device that stores the stop position of the print head when the temperature is at level 3; and a storage device that stores the stop position of the print head when the temperature detection device changes from the second level to no signal or a third level, and moves the print head in front of the cooling device. and a spacing mechanism that moves the print head to the stop position when the signal is absent or changes from a third level to a second level.