JPS59187878A - Recorder - Google Patents

Abstract

PURPOSE:To provide a recorder free from breakage of heaters or the like and enhanced in the useful life of a head and reliability, wherein when passing driving pulses to electro-thermal converters, driving pulses having a frequency and a pulse width of not smaller than predetermined values are inhibited from being impressed on heaters. CONSTITUTION:In a recorder so designed as to record by generating heat from electro-thermal converters, the period (t) for which an output l2 of a monostable multivibrator 4 is maintained at a low level is so set as to satisfy the relationship t<T-tp, where T is the maximum printing period and tp is the width of a printing pulse, whereby normal printing is conducted in an ordinary period. When pulses having a frequency of not smaller than a normal value, a printing command pulse STB is inputted in a period of time shorter than the period (t) set on the multivibrator 4, and an output Q2 of a J-K flip-flop 3 is outputted in a manner similar to that at normal time, but the output l2 of the multivibrator 4 remains at the low level, so that an output l3 of an AND gate 5 becomes low level, and the pulses are not impressed on the heaters 9a-9n.

Description

[Detailed Description of the Invention] (Conventional) Since this type of electric-thermal converter is a minute heater, it has the disadvantage that if excessive drive pulses are applied, it may shorten its life or cause the heater to break. Ta.

(Purpose) The present invention has been made in view of the above-mentioned difficulties, and it is possible to improve the lifespan and reliability of the head by prohibiting the application of drive pulses exceeding a predetermined frequency and pulse width to the heater. With the goal.

(Example) The present invention will be explained below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which 1 is a counter, 2 is an S-R flip-flop, 3 is a J-flip-flop, and 4 stable multi-by-breaks (
(hereinafter referred to as monomulti) 5° 6a-6 are AND gates, 7a-full are transistors, 8 is a print head, 9a-
9 is a heater.

The current print command pulse STB is 8.4 frig 70 g 20
When the set manual input S is entered, the S-4 flip-flop 2 is set and the output Q1 becomes H level and is applied to the J input of the flip-flop 6 as pJ-.

On the other hand, the reference clock E is frequency-divided by the counter 1, and the pulse width of the pulse applied to the heaters 9a to 9n is 5 (tpL!), which is the continuous pulse 61,1 (J- is the clock input of the flip-flop B). Given as CK.J-
The flip-flop 6 is set at the rising edge of the clock 11, and the output Q2 becomes the H level and the output KQ2 becomes the L level. This Qlj:S-Flip 70 is input to the reset human power R of the flip 2, the S-R flip frog 2 is reset, and the output Q1 changes to L level. Therefore, at the next 11 rising cycles, flip-flop 3 changes state to J-, and the output Q
2 becomes L level and Q2 becomes H level.

After that, if there is no STB signal, the J- input of flip-flop 6 is at LL/Bell and the K input is at H level, so even if 11 receives a large CK input, the state does not change, and the output Q2 becomes L. Level, Q2 maintains H level.

In this way, the output Q2 of the flip-flop J- outputs one pulse having the same width as the first period.

On the other hand, the output Q2 of the flip-flop 6 at J- is input to the monomulti 4, and its output 12 is kept at the L level for a certain period of time (1) due to the fall of the switch.

This 12 and the above-mentioned Q2 are input to the NAND gate 5,
Only when each input is at H level, its output 16 becomes H level, and the NAND gate 6 for driving the head
Each of b to 6rL is input by one person. The other inputs of the NAND gates 6a to 6rL are print data D1 to Dn.
is input and there is data, an H level output is applied to the transistors 7a to 7a. It is done.

FIG. 2 is a timing chart for explaining the operation of FIG. 1. Monomulti 4 out cuff! Time t to keep 2 at L level
J) according to the maximum printing cycle time T and the printing pulse width tp.
, t<'I'-tp is set so that it holds true, the above operation is repeated in the normal cycle, printing is performed normally, and now the state when a pulse with a frequency higher than the normal frequency is input will be explained using the timing chart of FIG.

At the first STB input, NAND is used as in the normal case described above.
The output l'5 of the gate 5 becomes H level for a time tp. Next, when the STB is inputted again in a shorter time than the time t set in the monomulti 4D, is outputted in the same way as in normal times. However, at this time, the output 12 of the monomulti 44 remains at the L level, so the output 16 of the AND gate 5 is at the L level, and no pulse is applied to the p-heaters 9a to 9n.

Also, according to the output Q2 at this time, the monomulti 4 is set again to keep the output at the L level for a certain period of time t, so no matter how many STB pulses below are input after this time, The output 16 of the AND gate 5 is held at the level, and no pulse is applied to the heaters 9a-9l. In the subsequent STB pulses, the output 12 of the monomulti 4 is at the H level, so the AND gate 5 is not at the H level for the time tp, and the heaters 9a to 9 are not energized. will be accomplished.

As mentioned above, the pulse with a period shorter than the set time t of the monomulti 44 eventually appears as the output e6 of the AND gate 5 of the final heater drive. Set time tl) Only long period pulses appear, and their width does not exceed one period of the output 11 of the counter 1.

(Effects) As explained above, according to the present invention, continuous pulses and long-width pulses that would cause abnormality to the heater of the head are not applied to the heater, preventing damage to the heater and extending the life of the heater. A highly reliable recording device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram and a second chart showing an embodiment of the present invention. 1: Counter 2s8-R7 flip-flop 3: Flip-flop to J- 4: Monostable multi-vibration break 8: Print head 9: Electricity-thermal converter (heater)

Claims (1)

[Scope of Claims] In a recording device that performs recording using heat generated by an electro-thermal converter, a drive pulse applied to the electro-thermal converter is prohibited from exceeding a predetermined frequency and a predetermined pulse width. Characteristic recording device. The present invention relates to a recording device that performs recording by providing a power source.