JPH03193365A - Thermal recorder - Google Patents

Abstract

PURPOSE:To fill blanks between recording dots in a line feed direction to obtain a good recording result by a method wherein when a shortage of energy is discriminated, a 1/2 line feed is conducted after a one-line recording, and recording data before the 1/2 line feed is again recorded. CONSTITUTION:When a shortage of energy is discriminated, a pulse motor 17 is driven by one step, and a strobe pulse STR A and a strobe pulse STR B are supplied to a thermal line head. A change-over pulse is outputted to a multiplexer 25 from a microcomputer 20, and a strobe pulse is supplied to a C group of the thermal line head 13. In this manner, after one rotation of supplying the strobe pulses STR A - STR D, the pulse motor 17 is driven by one step, and strobe pulses STR A - STR D are again supplied. As a result, recording is made after a 1/2 line feed. In this manner, recording with double- recorded dots is obtained while a white blank part between dots is filled with dots.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermal recording device that maintains recording density by performing recording control and line feed control in accordance with the temperature and line speed of a thermal line head or its vicinity.

(Prior Art) In a thermal recording device, the width of a strobe pulse (also referred to as a recording pulse in this specification) that is input to an AND means that provides an output to a heating element is changed depending on the temperature and line speed of a thermal line head. There is.

In this case, the strobe pulse width is set to be an ideal pulse width (also referred to as ideal pulse in this specification) at which the density of the recording result becomes a specified density depending on the temperature and line speed of the thermal line head.

Furthermore, if the strobe pulse width is insufficient due to line speed, a preheating method may be adopted in which a pulse of a predetermined width is applied to the heating element in advance to preheat it.

(Problem B to be solved by the invention) However, in the conventional thermal recording device as described above,
The strobe pulse width is greatly different between the high temperature/high speed case where the thermal line head is high temperature and the line speed is high, and the low temperature/low speed case where the thermal line head is low temperature and the line speed is low.

The relationship between the temperature of the thermal line head and the ideal pulse width is as shown in FIG. 8, for example. In the case of high temperature and high speed, the thermal line head is at a high temperature, so even if the strobe pulse width is short, the size of the recording result of one recording dot is large and the density is high. In the case of low temperature and low speed, the temperature of the thermal line head is low and the cycle period during which no strobe pulse is applied is long due to the low speed, so a long strobe pulse width is required. Since the strobe pulse width is limited, the size of the recorded one dot is small, and when viewed in the line feed direction, blank areas occur between the dots.

To explain this specifically, if the heat-sensitive element is divided into four blocks and strobe pulses are applied, and the maximum line speed is 10 m5ec/line, then
■The pulse width that can be given to the block is 2.5 m.
The maximum is 5ec, and the maximum is 2.4 m5ec with a margin.
When set to , a strobe pulse width of 2.4 m5ec or more is required in a portion above the broken line in FIG. However, since the longest strobe pulse width is set to 2.4 m5 ec, the recording energy applied to the heating element is insufficient in the portion beyond the broken line in FIG. In the case of insufficient recording energy, the dot size of the recording result is small as described above, and when viewed in the line feed direction, the dot size shown in Fig. 7 (
In (b), the recording is as shown by the shaded area, and the dots appear to be blank.

Note that if the energy is not insufficient, that is, if the strobe pulse width less than the broken line in FIG. 8 is sufficient, the recording energy is large and the dot size of the recording result becomes large, as shown in FIG. 7(a) when viewed in the line feed direction.
As shown in the figure, the recording does not look like white spots between the dots.

In other words, if the longest value of the strobe pulse width is set based on a predetermined case such as low temperature and high speed, if the strobe pulse width is less than the predetermined value such as low temperature and low speed, the strobe pulse width will be insufficient and the density will be insufficient, resulting in a decrease in recording density. There was a problem in that the concentration did not reach the specified concentration.

(Means for Solving the Problems) A thermal recording device of the present invention includes a thermal line head equipped with a heating element that generates heat by being energized by an output from an AND means that performs an AND operation between recording data and a strobe pulse; a moving means for intermittently moving the heat-sensitive recording medium relative to the thermal line head in a state where a part of the heat-sensitive recording medium is in contact with the thermal line head and facing the heating element; and the thermal line head or A thermosensitive recording device comprising: a strobe pulse control means for controlling the pulse width of the strobe pulse to a predetermined value or less according to the temperature in the vicinity thereof, and changing the period of the strobe pulse according to the line speed; A determining means is provided for determining whether the recording energy of the heating element is insufficient based on the speed and the temperature, and when the determining means determines that the recording energy is insufficient, the moving means moves the thermosensitive recording medium after generating a strobe pulse for one line. The present invention is characterized by comprising a re-recording means for applying the recorded data two line feeds ago and a strobe pulse to the AND means when the data is fed two lines.

Furthermore, the shortage of recording energy may be determined based on whether the strobe pulse width is a predetermined value.

(Function) In the thermal recording device of the present invention configured as described above, when the determining means determines that recording energy is insufficient based on the line speed and the temperature of the thermal line head or its vicinity, the thermal recording device generates a thermal recording device after generating a strobe pulse for one line. When the recording medium is fed each line by the moving means, the data recorded % before the line feed is re-recorded.

Therefore, the blank area that occurs between one line feed is filled with the same recording dot as the immediately preceding recording dot, and the blank area disappears.

(Example) The present invention will be explained below using examples.

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a schematic perspective view of a thermal recording device according to an embodiment of the invention, and Fig. 3 is a thermal line head in an embodiment of the invention. FIG. 4 is a circuit diagram of a strobe pulse generation circuit in an embodiment of the present invention.

In this example, the number of dots in the line direction is 1728, and 7
An example is shown in which the strobe pulse is supplied divided into four blocks: three blocks of ×64 dots and one block of 6×64 dots.

As shown in FIG. 2, the thermal recording apparatus according to one embodiment of the present invention has platen shafts 14 extending from the platen 12 on both sides, and one
The platen shaft 14 is rotatably supported by a pair of frames 10 and 101. The thermal line head 13 faces the platen 12 and is supported by the frame 1O110'. A platen drive wheel 15 is attached to the platen shaft 14. Platen drive wheel 15
A belt 16 is wound around the rotor shaft of a step motor 17 attached to the frame 10, and the step motor 17 drives the platen drive wheel 15 via the belt 16. A thermal paper 18 constituting a thermal sheet-like recording medium is disposed between the thermal line head 13 and the platen 12, and is configured to be conveyed in a direction perpendicular to the platen shaft 14 by rotation of the platen 12.

In this embodiment, the step motor 17 is constituted by a four-phase step motor, driven by two-phase excitation, and one line is fed in two steps.

As shown in Fig. 1, the thermal recording device has a central processing bag Tt (
CPU) 21, ROM 22 that stores programs
, a microcomputer 20 consisting of a RAM 23 that temporarily stores recording data, a strobe pulse generation circuit 24 that receives a trigger pulse output from the microcomputer 20 and outputs a strobe pulse, and a strobe pulse output from the strobe pulse generation circuit 24. A multiplexer 25 receives input strobe pulses and outputs input strobe pulses to blocks A, B, C, or D of the thermal line head 13 according to a selection signal output from the microcomputer 20.
Upon receiving one line of record data read from AM23, the record data is latched by a latch pulse outputted from the microcomputer 20 at a cycle corresponding to the communication speed, and the latch record data is sent to the thermal line head 13. It includes a data latch circuit 26 that outputs data, and a motor control circuit 27 that receives drive control pulses output from the microcomputer 20 and generates two-phase pulses that drive the step motor 17.

As shown in FIG. 3, the thermal line head 13 has an AND gate 1 which receives the output of the data latch circuit 26 and the strobe pulse output from the multiplexer 25.
31 to 13 □, and resistors 13, 1 to 13. as heating elements which generate heat by inputting the outputs from each of the ant games 113, to 13 □ separately. .

and a thermistor 13zo for detecting the temperature near the thermal line head 13.

In FIG. 2, each AND gate 131-1327 and a resistor 133. .about.1357 collectively indicate 64 dots. Note that the division into groups A to D is as described above.

In the thermal line head 13 described above, the output of the data latch circuit 26 is logic 111TT, and the strobe pulse output from the multiplexer 25 is logic II.
I I+ period, corresponding anime game) 131,
-・13□7 generates a logic "1" output, logic I
Ant game 1-13 generating T I I+ output
, , -13□, resistor 1331, -13 connected to
, 7 are energized and generate heat. The temperature near the thermal line head 13 (hereinafter simply referred to as temperature) is detected by the thermistor 133°.

As shown in FIG. 4, the strobe pulse generation circuit 24 receives a trigger pulse output from the microcomputer 21 and is set to generate an output pulse of a maximum length of 2.4 m5 ec when the maximum line speed is 10 m5 ec, as in the conventional case. Monostable multi-bi break with variable output pulse width 24. and a time constant circuit 24 for varying the output pulse width of the monostable multi-bi break 244 by the resistance value of the thermistor 13io. It is equipped with The time constant circuit 246 has a resistor 24.1 having one end pulled up to the power supply voltage and a thermistor 133o connected in parallel. and,
Resistance 24. Resistor 24□ connected in series with resistor 24□
It consists of a capacitor 243 connected between one end of the resistor 24□ and the ground, and supplies the potential at the connection point between the resistor 24□ and the capacitor 24□ to the monostable multi-high break 244 as an output pulse width variable signal. Furthermore, the output pulse of the monostable multivibrator 244 is
It is designed to be read by inserting it into a folder.

The strobe pulse generation circuit 24 configured as described above is
A strobe pulse is output from the monostable multi-bibreak 244 in response to a trigger pulse output from the microcomputer 20.

On the other hand, the output pulse width of the monostable multi-bi break 244 is determined by the thermistor 13. o is controlled according to the detected temperature.

Additionally, the microcomputer 20 outputs four trigger pulses in succession every 2.5 m5ec, and the four trigger pulses are considered as one block, which are repeated at a cycle according to the line speed, except in the case of double strikes described later. It will be done.

The operation of one embodiment of the present invention constructed as described above will be explained with reference to the waveform diagram in FIG. 5 and the flowchart in FIG. 6.

When recording starts, the output pulse width from the strobe pulse generation circuit 24 is read and the thermal line head 1 is
The temperature of step 3 is calculated, the line speed in response to the speed information is calculated, the recording energy is calculated from the temperature and the line speed (step S,), and the calculated recording energy is the longest strobe pulse width of 2. It is checked whether the recording energy is greater than or equal to the recording energy at 4 m5ec (step S2). Checking in step S2 is performed by referring to the table shown in FIG. 8, which is stored in the ROM 22. When the strobe pulse width is less than 2.4 m5 ec, there is no shortage of recording energy, and in this case it is less than the broken line in FIG. In this case, following step S2, a drive control pulse is output from the microcomputer 20, and the step motor 17 is driven one step by the excitation output from the motor control circuit 27. Further, the microcomputer 20 outputs a switching pulse for the multiplexer 25, and the multiplexer 25 is switched to supply strobe pulses to group A of the thermal line head 13. Furthermore, a trigger pulse is supplied to the strobe pulse generation circuit 24 (step S). Step S3
In response to the trigger pulse, the monostable multi-high break 24 outputs a strobe pulse with a pulse width of 2.4 m5 ec or less, and this strobe pulse is supplied to the thermal line head 13 as a strobe pulse 5TRA via the multiplexer 25 (step S4)
.

In step S4, since there is no shortage of recording energy, the strobe pulse width becomes 2.4111 sec as the temperature detected by the thermistor 133° increases.
The following is true. 2, 5 from the start of execution of step S3
When m5ec has elapsed, a switching pulse is output from the microcomputer 20 to the multiplexer 25, and the multiplexer 25 is switched to supply strobe pulses to group B of the thermal line head 13. Further, a trigger pulse is supplied to the strobe pulse generation circuit 24 (Stella 7"SS). The strobe pulse generator 24 that has received the trigger pulse generates a strobe pulse in the same manner as in step S4, and this strobe pulse is generated as a strobe pulse 5TRB. Supplied to the thermal line head (
Step S6). 2 from the start of execution of step S,
When 5 m5ec has elapsed, steps 37 to SIO are executed in the same way as steps 37 to S6. In step S7, the pulse motor 17 is driven by one step, the strobe pulse generation circuit 24 is triggered, and the generated strobe pulse is sent to the multiplexer 25.
is supplied to the thermal line head 13 as a strobe pulse 5TRC (steps S, , S,).

Step S9 is similar to step S5,
A trigger pulse is supplied to the strobe pulse generation circuit 24, and the generated strobe pulse is supplied to the thermal line head 13 as a strobe pulse 5TRD via the multiplexer 25 (Step Sq, St.). 2. From the time of execution of step S. When 5 m5ec has elapsed, the process waits until the next line recording is ready and executes again from step S1 (step S).

The above state is shown in a waveform diagram as shown in FIG.

That is, the trigger pulse of the strobe pulse generation circuit 24 supplied from the microcomputer 20 is as shown in FIG.
) as shown. Note that the interval between trigger pulses is 2
, 5 m5ec, and the period of each of the four trigger pulses is the same as the line speed. Therefore, when the line speed is 1Qmsec, the period of each trigger pulse is 1Qa+sec, and a portion thereof is as shown by a broken line.

The trigger pulses output in steps S4, S6, S8, and Sto are as shown in FIG. 5), (C), (d), and (e). FIGS. 5(b) to 5(e) are shown schematically as shown in FIG. PA-PD indicates the name of each phase winding of the step motor, and the phase winding name added in Fig. 5) indicates the excitation phase winding, and the same applies hereinafter.

The four strobe pulses shown in FIG. 5(f) are simplified and shown in FIG.

Using the simplification shown in Figure 5(g), the strobe pulse when the line speed is 10m5ec is shown in Figure 5(h).
Similarly, the line speed is 20m5e.
The strobe pulse when the line speed is C is shown in Figure 5 (i), the strobe pulse when the line speed is 43 m5 ec is shown in Figure 5 (j), and the strobe pulse when the line speed is 60 m5 ec is shown in Figure 5 (k). As shown respectively. Moreover, if FIG. 5(h) is enlarged, it looks like FIG. 5(ff).

In the above Figure 5(b) to string), the temperature near the thermal line head 13, that is, the influence of the temperature on the thermal line and the throat, was ignored in the explanation, but when the line speed is lQmsec and the temperature is approximately 0°C. When the line speed is lQmsec and the temperature is approximately lOoC, the strobe pulse has a narrow pulse width as shown in Fig. 5(m), and when the line speed is 10m5ec, the temperature is is almost 25°C
In this case, the pulse width of the strobe pulse becomes even narrower as shown in FIG. 5(n).

Also, taking the case of a line speed of 4Qmsec as an example, when the temperature is approximately 30°C, the width becomes narrow as shown in Figure 5 (q), and when the temperature is approximately 45°C, it is shown in Figure 5 (r). It becomes even narrower.

If it is determined in step S2 that the recording energy is insufficient, step S2 is followed by steps 33 to 33.
Steps SL3 to 316 similar to S6 are executed. By executing steps S13 to Sl&, the pulse motor 17 is driven by one step, and strobe pulses 5TRA and 5TRB are supplied to the thermal line head.

2,5 m5ec from the start of execution of step 315
When the time has elapsed, a switching pulse is outputted from the microcomputer 20 to the multiplexer 25 following step S16, and the multiplexer 25 is switched to supply the strobe pulse to the zero group of the thermal line head 13. Further, a trigger pulse is supplied to the strobe pulse generation circuit 24 (step S,...). Step S1□
is the same as step S except that the pulse motor 17 is not driven in one step. The trigger pulse generating circuit 24 that received the trigger pulse in step SI7 generates a strobe pulse as in steps SI4 and SI6, and this strobe pulse is supplied to the thermal line head 13 as a strobe pulse 5TRC (step 518). Following step Sll+, step 319 similar to steps S, ~S10
~S2° is executed. Strobe pulse 5TRD is supplied to thermal line head 13 by executing steps S1'1 to S2°.

Following step S2°, from the start of execution of step SI9, 2. When 5 m5ec has passed, step 813
Step 5IffA''S2°, which is similar to ~S2°, is executed. Therefore, in contrast to the execution of steps SI3 to S2°, when step SI3A ""' S2° is executed, the step motor 17 is driven by one step. Step S11 is executed following step S20A.

Here, steps S13 to S2° and step 5lf
When the steps f-S2° are executed, the recording energy is insufficient, that is, the line speed and temperature exceed the broken line in FIG. A pulse with a pulse width of 4 m5ec is output, and the pulse width of the strobe pulses 5TRASTRB, 5TRC and 5TRD is 2.4 m5ec.

Therefore, steps S13 to S2° and step 5I
When 3A-32° is executed, in the case of the example shown in Fig. 8, the line speed is 20m5ec and the temperature is approximately 8.
If the temperature is below 18°C, the line speed is 43m5ec and if the temperature is below approximately 18°C, the line speed is 53m5ec.
ec and the temperature is approximately less than 28°C.

Conventionally, even when the recording energy is insufficient, steps 33 to S11 are repeated to perform recording, and the strobe pulses 5TRA-3TRD at this time are as shown in FIG.
) as shown.

On the other hand, according to this embodiment, the strobe pulse 5TR
The waveforms of A, 5TRB, 5TRC, and 5TRD are shown in Figure 5 (p.
), and as is clear from the comparison with FIGS. 5(i) to (g), the strobe pulse 5TRA-3TR
After D has been supplied once, the pulse motor 17 is driven one step, and the strobe pulse 5TRA- is again applied.
ATRD will be supplied. As a result, when viewed in the line feed direction, recording is performed at two line feeds, and the recording dots are recorded between the shaded areas in FIG. 7(b), resulting in a double strike state. The white gaps between the dots will be filled in in the record.

Further, since this control is performed only when the line speed is 20 m5ec/line or more, the line speed as a whole does not decrease even if only a slight change in line feed control and an increase in rest time control are made.

(Effects of the Invention) As explained above, according to the thermal recording device of the present invention, the lack of recording energy is determined based on the temperature near the thermal line head and the line speed, and when it is determined that there is a shortage of recording energy, after recording one line. When each line feed is performed, the recorded data before the A line feed is recorded again, so that in the case of insufficient recording energy, the blank space between recording dots in the line feed direction is filled.
Good records can be obtained.

Further, since this control is performed only at low speeds of 20 m5ec/line or more, there is no reduction in line speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a schematic perspective view of a thermal recording device according to an embodiment of the present invention. FIG. 3 is a circuit diagram of a thermal line head section in an embodiment of the present invention. FIG. 4 is a circuit diagram of a strobe pulse generation circuit in one embodiment of the present invention. FIG. 5 is a waveform diagram for explaining the operation of an embodiment of the present invention. FIG. 6 is a flowchart for explaining the operation of one embodiment of the present invention. The seventh is a schematic diagram showing recording dots for explaining the operation of an embodiment of the present invention. FIG. 8 is a characteristic diagram showing the relationship between line speed, temperature, and strobe pulse width. 12...Platen, 13...Thermal line head, 133o...Thermistor, 15...Drive wheel,
16...Belt, 17...Pulse motor, 18...
・Thermal paper, 24... Strobe pulse generation circuit, 24
4... Monostable multi-by-break, 25... Multiplexer, 26... Data latch circuit, 27... Motor control circuit.

Claims (2)

[Claims] (1) A thermal line head equipped with a heating element that generates heat by being energized by the output from an AND means that performs an AND operation on recording data and a strobe pulse, and a part of the thermal recording medium is brought into contact with the thermal line head. and a moving means for intermittently moving the thermosensitive recording medium relative to the thermal line head while facing the heating element, and a pulse width of the strobe pulse depending on the temperature of the thermal line head or its vicinity. In a thermosensitive recording device comprising a strobe pulse control means that controls the strobe pulse below a predetermined value and changes the period of the strobe pulse in accordance with the line speed, the recording energy of the heating element is insufficient based on the line speed and the temperature. and when the determining means determines that recording energy is insufficient, the moving means moves the thermosensitive recording medium by 1/2 after generating a strobe pulse for one line.
A thermosensitive recording device comprising: a re-recording means for applying the recorded data before the 1/2 line feed and a strobe pulse to the AND means when two lines are fed. (2) The thermal recording apparatus according to claim 1, wherein the determining means is a determining means that determines that recording energy is insufficient when the width of the strobe pulse generated by the strobe pulse control means is a predetermined value.