JP3013211U - Thermal recording device - Google Patents

Abstract

(57) [Abstract] [Purpose] A thermal recording device that can detect overheat and fire accidents by detecting the disconnection of the temperature detection thermistor. A TPH is provided with a sensor circuit 2 for detecting the temperature of a thermal recording head TPH1, and a temperature measuring circuit 3 for measuring the detected temperature value and sending it to a monitoring means 4 after A / D conversion.
The temperature of the sensor circuit is compared with the temperature after printing a certain amount or the temperature after preheating to detect the thermistor disconnection of the sensor circuit.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a thermal recording apparatus used in a facsimile or the like, and more particularly to a thermal recording apparatus capable of coping with a failure by monitoring the operating state of a means for detecting the temperature of a thermal recording head.

[0002]

[Prior art]

 FIG. 2 is a block diagram of a conventional thermal recording apparatus. A control program stored in the ROM 103 and the processing of the CPU 102 cause the control unit 101 for controlling the entire apparatus to print data a and print pulses b stored in the RAM 104. The thermal recording head 111 is divided into several blocks and sequentially added, and the heating resistance element of the thermal recording head 104 corresponding to the print data is driven by the drive current from the power supply circuit 105 to generate heat and print on the recording paper. Be seen.

Under the control of the control unit 101, the recording paper conveyance motor 107 rotationally drives the platen 108 and the roller 109 via the driver circuit 106 to feed the paper and prepare for the next printing. Further, the temperature of the thermal recording head 111 is detected by a sensor circuit 110 such as a thermistor, and when the temperature is low and the print density is low, the density is adjusted by preheating or the like, and conversely overheat is detected. At times, printing is stopped and cooling is performed.

[0004]

[Problems to be solved by the device]

 However, in the above-mentioned conventional example, since the temperature sensor does not have a check function, the temperature adjustment function of the thermal recording head becomes inoperable when normal temperature detection cannot be performed due to a failure such as thermistor disconnection in the sensor circuit. Therefore, there is a problem that continued use of the device in this state will lead to overheating and fire accident.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a thermal recording device capable of detecting a failure occurrence such as a thermistor disconnection of a sensor circuit and preventing the occurrence of overheating or ignition accident.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a thermal recording apparatus having a thermal recording head in which a plurality of heating elements are arranged in a row, and a temperature detecting means for detecting the temperature of the thermal recording head and the temperature detecting means. It is characterized by further comprising monitoring means for comparing the temperature of the thermosensitive recording head detected at a predetermined time with the temperature after printing a fixed amount from that time to monitor the operating state of the temperature detecting means.

Further, in a thermal recording apparatus having a thermal recording head in which a plurality of heating elements are arranged in a row, temperature detecting means for detecting the temperature of the thermal recording head and raising the temperature of the thermal recording head to a predetermined value. Preheating means and monitoring means for monitoring the operating state of the temperature detecting means by comparing the temperature of the thermal recording head detected by the temperature detecting means at a predetermined time with the temperature of the thermal recording head by the preheating means. It is characterized by having. Further, the preheating means is characterized in that the preheating data is continuously sent at a temperature at which printing is not performed or the preheating heater is used to heat the heater. Further, it is characterized in that a warning notification means is provided for stopping the recording operation and issuing a warning when the monitoring means judges that the temperature detection means cannot detect the temperature.

[0008]

[Action]

 According to the above invention, since the monitoring means judges the operating state of the temperature detecting means by comparing the temperature of the thermal recording head at a predetermined time with the temperature after printing a fixed amount, the temperature at the predetermined time and after printing the fixed amount. It is possible to monitor whether or not the operating state of the temperature detecting means is normal by comparing the temperature at which the temperature is to be raised. Further, since the monitoring means judges the operating state of the temperature detecting means by comparing the temperature of the thermal recording head at a predetermined time with the temperature after preheating, the temperature at the predetermined time is compared with the temperature to be raised after preheating. By doing so, it is possible to monitor whether or not the operating state of the temperature detecting means is normal. Further, the preheating means continuously sends the data for preheating at a non-printing temperature to the thermal recording head a predetermined number of times or heats the thermal recording head with a preheating heater. Further, when the monitoring means does not raise the temperature to be raised after printing a certain amount or the temperature to be raised after preheating, the temperature detecting means judges that the temperature cannot be detected, stops the recording operation, and informs the display section whether the temperature is high or not. Etc.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a thermal recording apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 is a thermal recording head (TPH) having a row of heating resistance elements, which is divided into several blocks and driven for each block. Reference numeral 2 is a temperature sensor circuit that uses a PTC (Positive Temperature Coefficient) type thermistor or a CTR (Critical Temperature Resistor) type thermistor that detects the temperature of TPH1.

Reference numeral 3 denotes a temperature measuring circuit that measures the temperature from the detected value of the sensor circuit 2, A / D-converts the measured value, and outputs it to the control unit 101. Reference numeral 4 is a monitoring means for monitoring the operating state of the sensor circuit 2 by comparing the measured temperature of the TPH 1 with the temperature after printing a fixed amount. Reference numeral 5 is a power supply for energizing the TPH 1. It should be noted that the same configurations as those of the other conventional examples are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described. In a facsimile as shown in FIG. 1, normally, preheating is performed in order to raise the operating temperature of TPH1 at low temperature and eliminate uneven printing. In the preheat in this case, the temperature of TPH1 is detected by the sensor circuit 2, the temperature value measured by the temperature measurement circuit 3 is input to the microcomputer control unit 101, and the control unit 101 sets the set reference temperature. As a reference, when the measured temperature is lower than that, preheat data is continuously sent to TPH1 at a temperature at which printing is not performed, or if a preheat heater is provided, preheat is performed by heating the heater.

When the detected temperature value reaches the printable temperature, the control unit 101 stops the preheating, sends the print data a stored in the RAM 104 and the print pulse b for driving to the TPH1, and starts the print recording. The TPH 1 prints print data by driving the heating element to generate heat by the drive current from the power supply circuit 5 at the timing of the print pulse. If TPH1 overheats above the limit temperature for some reason during printing, energization to TPH1 is turned off and printing is stopped until the temperature drops and protection processing is performed.

Further, in this embodiment, the operating state of the sensor circuit 2 is checked by the monitoring means 4 at a predetermined timing. When the power of the device is turned on, the control unit 101 detects the temperature of TPH1 via the sensor circuit 2 and the temperature measuring circuit 3. Then, the preheating is performed for a certain period of time to measure the temperature after the preheating, and the monitoring means 4 compares the two temperatures and if the temperature of TPH1 rises as a predetermined amount by the preheating, the sensor circuit 2 and its thermistor It is judged to be operating normally without any failure such as disconnection. When the judgment of the monitoring means 4 is normal, the control unit 101 continues the preheating, and when the detected temperature reaches the predetermined temperature, the preheat is stopped and the print recording is started.

When the preheating is not performed, first the temperature of the TPH 1 is measured and the temperature value is stored, a certain amount of print is recorded and then the temperature of the sensor circuit 2 is measured again, and the monitoring means 4 When the temperature rise is detected from the temperature comparison, the sensor circuit 2 judges that there is no abnormality and continues printing and recording.

If no temperature rise is detected in the temperature check of these monitoring means 4, the sensor circuit 2 judges that the temperature cannot be detected due to a disconnection accident or the like. If printing and recording are continued in that state, the temperature control function that operates based on the detection value of the sensor circuit 2 to automatically stop the energization is inoperable, so TPH1 becomes overheated and the last In this case, the power supply to TPH1 is turned off to prohibit printing and recording, and a warning is displayed on a display device (not shown). The temperature check by the monitoring means 4 is performed and monitored at predetermined time intervals, for example, every 30 minutes (not particularly limited to 30 minutes) even during normal operation of the apparatus.

[0017]

[Effect of device]

 As described above, according to the thermal recording apparatus of the present invention, the temperature detecting means and the preheating means of the thermal recording head, the temperature of the thermal recording head at a predetermined time point and the temperature after printing a certain amount or the temperature after preheating are measured. By providing a monitoring means and a warning notifying means to monitor the operating state of the temperature detection means in comparison, it is possible to prevent overheating and ignition accidents caused by temperature control uncontrollable state due to failure such as sensor circuit thermistor disconnection. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a block diagram of a thermal recording apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional thermal recording device.

[Explanation of symbols]

 1 TPH 2 sensor circuit 3 temperature measuring circuit 4 monitoring means 5 power supply

Claims (4)

[Scope of utility model registration request] 1. A thermal recording apparatus having a thermal recording head in which a plurality of heating elements are arranged in a row, wherein a temperature detecting means for detecting a temperature of the thermal recording head and the thermal recording head detected by the temperature detecting means. A heat-sensitive recording apparatus comprising a monitoring means for comparing the temperature at a predetermined time with the temperature after printing a certain amount from that time to monitor the operating state of the temperature detecting means. 2. A thermal recording apparatus having a thermal recording head in which a plurality of heating elements are arranged in a row, and a temperature detecting means for detecting the temperature of the thermal recording head, and raising the temperature of the thermal recording head to a predetermined value. Preheating means, and a monitoring means for comparing the temperature of the thermal recording head at a predetermined time detected by the temperature detecting means with the temperature of the thermal recording head by the preheating means to monitor the operating state of the temperature detecting means. A thermal recording device characterized by the above. 3. The heat-sensitive recording apparatus according to claim 2, wherein the preheating means is configured to continuously send preheating data at a temperature at which printing is not performed or to heat a heater of a preheating heater. 4. A warning notifying unit for stopping the recording operation and issuing a warning when the temperature detecting unit determines that the temperature detecting unit cannot detect the temperature by the monitoring unit. Thermal recording device.