JP2693646B2 - Recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus, for example, a recording apparatus which drives a thermal head to generate heat to record on a recording medium.

[0002]

2. Description of the Related Art Conventionally, in this type of recording apparatus, in order to keep the recording density constant, a thermistor as a temperature sensor for detecting the temperature of the thermal head is provided in the thermal head, and the temperature sensor The temperature of the thermal head was detected based on the signal, and the energy applied to the thermal head was controlled. As a result, the temperature of the thermal head is kept substantially constant and the recording density is kept constant.

[0003]

However, in the above conventional example, when it is determined that the thermistor in the thermal head has failed and the temperature of the thermal head has become abnormally high, the recording operation is stopped and thereafter I was trying to prohibit the recording of. Therefore, there is a problem that the user cannot use the printer for a long time because the user cannot judge whether the device has failed or whether the thermal head has become hot.

Also, the service person who received the notification due to the above trouble may have the thermal head failed.
Or I couldn't determine if the device was faulty, so I had to deal with it by replacing the thermal head. As described above, there is a problem that an expensive thermal head may be replaced even though the thermal head is not actually broken.

The present invention has been made in view of the above conventional example, and when detecting the temperature rise of the electrothermal converter, it is possible to determine whether it is due to an abnormality of the temperature sensor or due to the temperature rise of the electrothermal converter. It is an object to provide a recording device.

[0006]

In order to achieve the above object, the recording apparatus of the present invention has the following constitution. That is, in a recording device that drives an electrothermal converter to generate heat and records it on a recording medium, the temperature detecting means provided in the vicinity of the electrothermal converter and the temperature detected by the temperature detecting means are equal to or higher than a predetermined temperature. When it is determined that the temperature detected by the temperature detecting means is continuously equal to or higher than the predetermined temperature until the time measuring means for starting the time measurement of the predetermined time and the predetermined time is measured by the time measuring means. Has a judging means for judging that the temperature detecting means is defective.

[0007]

In the above structure, when it is determined that the temperature detected by the temperature detecting means provided in the vicinity of the electrothermal converter is equal to or higher than the predetermined temperature, the counting of the predetermined time is started. Then, when the temperature detected by the temperature detecting means continues to be equal to or higher than the predetermined temperature until the predetermined time is measured, the temperature detecting means operates to determine that the temperature is defective.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. <Description of facsimile machine
(FIGS. 1 and 2)> FIG. 2 is a block diagram showing a schematic configuration of a facsimile apparatus of this embodiment, and FIG. 1 is a block diagram showing a connection between a control unit and a recording unit in the facsimile apparatus.

First, the configuration of the facsimile apparatus according to the present embodiment will be described with reference to FIG.

In the figure, reference numeral 200 denotes a reading unit which photoelectrically reads a document and outputs it as a digital image signal to the control unit 101, and includes a document feeding motor, a CCD image sensor and the like. Explaining the configuration of the control unit 101, 214
Is a line memory for storing the image data of each line of the image data, and is a reading unit 2 when transmitting or copying an original.
The image data for 1 line from 00 is stored, and when receiving the image data, 1 of the decoded received image data is stored.
Line data is stored. Then, by outputting the stored image data to the recording unit 102, an image is formed on a recording medium such as recording paper. Reference numeral 215 denotes an encoding / decoding unit that encodes image information to be transmitted by MH code or the like, and decodes the received encoded image data to convert it into image data. A buffer memory 216 stores coded image data transmitted or received. Each unit of the control unit 101 described above is controlled by the CPU 211 such as a microprocessor. Reference numeral 212 is a ROM that stores the control program of the CPU 211 and various data, and 213 is a C
It is a RAM used as a work area of the PU 211.

Reference numeral 102 denotes a recording unit, which is provided with a thermal line head and records an image on recording paper by a thermal recording method or the like. An operation unit 203 includes a start key for instructing the start of transmission, various function keys for inputting a telephone number, and the like, and is operated by an operator to input various function instructions. Reference numeral 204 is a display unit normally provided in the operation unit 203, which is composed of, for example, a liquid crystal, and displays various functions and the state of the device. Reference numeral 205 is a power supply unit for supplying power to the entire apparatus, 206 is a modem (modulator / demodulator), and 207 is a network control unit (NC) that executes various communication controls with the line.
U). Reference numeral 208 is a telephone, and 209 is a buzzer, which sounds when an error described later occurs to notify the operator that the apparatus is malfunctioning.

Next, the electrical connection between the control unit 101 and the recording unit 102 will be described with reference to FIG.

The thermal head 110 is a line head,
The thermal head 110 is a shift register for serially inputting recording data for one line from the control unit 101, a latch circuit for latching recording data for one line, and a heating element for one line (for example, 1024).
Individual). Reference numeral 111 denotes a thermistor provided in the thermal head 110, which is mounted near the heating element of the thermal head 110 to detect the temperature of the thermal head 110. The thermistor 111 changes its resistance value depending on the temperature. The change in the resistance value is taken out as a voltage signal, converted into a digital signal by the A / D converter 103 of the control unit 101, and then the CPU 21.
Taken into 1. Reference numeral 214 denotes a timer, which starts the time counting according to the instruction of the CPU 211 and outputs the time to the CPU 211 by an interrupt or a signal when the time counting of the time designated by the CPU 211 ends.

Reference numeral 116 is a recording paper sensor for detecting the end of the recording paper, 112 is a motor for conveying the recording paper, and the motor driver 114 rotationally drives the motor 112 so that the recording paper has a desired length. Can be transported. Reference numeral 113 denotes a cutter for cutting the recording paper after recording one page, which is driven by a cutter driver 115.

FIG. 3 is a diagram showing the relationship between the temperature in the thermistor 111 and the resistance value of the thermistor. Here, the resistance value becomes lower as the temperature rises. Here, when the temperature is between t0 and t1, that is, when the resistance of the thermistor 111 is between r0 and r1,
The thermal head 110 can be used as normal and the resistance is r
When 1 <r2 and r3 <r0, recording by the thermal head 110 is prohibited as an abnormality. <Description of Operation (FIGS. 1 to 4)> FIG. 4 is a flowchart showing a temperature detection process of the thermal head 110 in the facsimile apparatus of the embodiment. This process is performed by an interrupt signal output from the timer 214 in a predetermined time unit, for example. The control program which is started and executes this processing is stored in the ROM 212.

First, in step S1, the thermal head 11
0 digital data from the thermistor 111 (the voltage value based on the resistance value of the thermistor 111 is converted into the A / D converter 1
Entered in step S2).
Then, it is determined whether the value is within the allowable range. If it is within the allowable range, the process proceeds to step S3 and the timer 21
4 resets the timer flag indicating that the time measurement is in progress, and sets the print enable flag indicating that the normal recording operation is possible. The timer flag and the print enable flag are set in the RAM 213.

If it is not within the allowable range in step S2, the process proceeds to step S4, and it is determined whether the timer flag is on. If it is off, the process proceeds to step S5, the timer flag is turned on, the counter of the RAM 214 is set to "0", and the process returns to the main process. If the timer flag is on, the process proceeds to step S6 and the counter is incremented by one. . Therefore, when this timer interrupt is input every 200 msec, for example, when the counter value becomes "5", "1"
It is determined that "second" has elapsed.

Next, in step S7, it is checked whether or not the value of this counter is greater than or equal to a predetermined value. If it is not greater than or equal to the predetermined value, the process proceeds to step S9 and returns to the main processing. Then, the print enable flag is turned off to prohibit the recording operation, and an alarm is output. This alarm output is performed by turning on an error lamp of the operation unit 203 or sounding a buzzer.

In this way, if the thermal head 11
When the temperature of 0 actually rises abnormally, for example, if it waits for several hundreds of milliseconds or about 1 second, it should be cooled sufficiently and the temperature should drop, but if the temperature of the thermal head is actually If the temperature sensor does not rise abnormally and the temperature sensor is abnormal, it cannot be recognized that the temperature of the thermal head has dropped even after the elapse of a predetermined time. Therefore, in such a case, as an abnormality of the temperature sensor, the buzzer 209 is sounded and an alarm is output to notify the operator of that.

In the above flow chart, when the print enable flag is in the off state, the recording operation is not performed even when the facsimile image signal is received and printing is performed.

In this embodiment, the temperature abnormality of the thermal head is detected by software, but it may be realized by a hardware circuit. For example, when the resistance value of the thermistor 111 of the thermal head 110 is close to infinity or extremely small, the counting operation of the counter is started, and when the counter counts a predetermined number, it is determined that there is an abnormality and a trigger is output. With such a configuration, the device of this embodiment can be realized only by a circuit using hardware.

In the present embodiment, the case of the facsimile machine is explained, but the recording apparatus of the present invention is not limited to this, and for example, a thermal transfer printer or a thermal printer connected to a word processor or the like may be used. Good. Furthermore, the present invention can be applied to an ink jet printer in which the electrothermal converter is subjected to a rapid temperature rise exceeding nucleate boiling of ink droplets to generate bubbles in the ink droplets for recording.

As described above, according to this embodiment, when the temperature abnormality of the thermal head is detected, it can be easily detected whether the temperature of the thermal head is actually high or the temperature sensor causes a failure. As a result, it is possible to save unnecessary time for detecting a failure, and save time and cost required for services such as maintenance.

[0024]

As described above, according to the present invention, when detecting the temperature rise of the electrothermal converter, it is possible to easily discriminate between the temperature sensor abnormality and the electrothermal converter temperature rise. There is an effect that can be done.

[Brief description of the drawings]

FIG. 1 is a diagram showing a connection between a control unit and a recording unit of a facsimile apparatus of this embodiment.

FIG. 2 is a block diagram showing a schematic configuration of a facsimile apparatus of this embodiment.

FIG. 3 is a diagram showing a temperature-output resistance curve of the thermistor of the example.

FIG. 4 is a flowchart showing a temperature detection process of the thermal head of the facsimile apparatus of this embodiment.

[Explanation of symbols]

 101 Control Unit 102 Recording Unit 103 A / D Converter 110 Thermal Head 111 Thermistor 209 Buzzer 211 CPU 212 ROM 213 RAM 214 Timer

Claims (2)

(57) [Claims] 1. A recording apparatus for driving an electrothermal converter to generate heat to record on a recording medium, the temperature detecting means being provided in the vicinity of the electrothermal converter, and the temperature detected by the temperature detecting means. Is determined to be equal to or higher than the predetermined temperature, the temperature detected by the temperature detection means continues until the predetermined time is measured by the time measurement means for starting the time measurement for the predetermined time, and the predetermined time is measured by the time measurement means. A recording device comprising: a determination unit that determines that the temperature detection unit is defective when the temperature is equal to or higher than the temperature. 2. The recording apparatus according to claim 1, further comprising an informing unit for informing that the temperature detecting unit is defective when the determining unit determines that the temperature detecting unit is defective.