JPS61173961A - Thermal recording system - Google Patents

Abstract

PURPOSE:To apply heat generating energy optimum to the temp. of a thermal head without generating overheating, by recording the detected temp. of the thermal head at the time of previous recording and controlling the supply of heat generating energy to a heat generating element corresponding to the temp. change between the recorded temp. and the detected temp. of the thermal head at the time of the next recording. CONSTITUTION:A recording part 5 receives informations such as a recording mode, a line end or a page end and image data from a main control part 1 at the recording CPU2 thereof and transmits the received image data to a thermal head 3. A temp. sensor 3a is provided to the head 3 and the temp. of the thermal head 3 at this point of time is read by the recording CPU. The recording CPU determines heat generating energy to be applied to a heat generating element corresponding to detected temp. and drives the heat generating element through a driver 4. The control of heat generating energy can be theoretically and finely performed at every one line or several lines but practically performed at every one page of a manuscript.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a thermal recording method, and more specifically, the present invention relates to a thermal recording method.
Alternatively, it relates to a thermal recording method that can be applied to various thermal recording devices that perform recording directly on thermal recording paper or perform recording by discharging droplets using heat. [Prior art] ÷ Performing thermal recording In this method, a thermal head having a plurality of heating elements is used, and the heating elements generate heat according to a recording command.

Such a thermal head has conventionally been provided with a temperature sensor using a thermistor or the like, which detects the temperature at the start of recording and determines the pulse width to be applied to the heating element in accordance with this temperature.

The pulse width at this time is relative to the temperature detected by the temperature sensor.
Control is performed so that the corresponding pulse width is determined on a ratio of 1 to 1 so that the recording density is always constant.

Then, record one page with this pulse width,
When the recording is finished, it returns to the original state and repeats the same recording operation again.

By the way, when the above-mentioned recording method is adopted, the applied energy that corresponds to a certain detected temperature for each body is determined, and when the same temperature, for example 50 degrees Celsius, is detected, the corresponding pulse A width of applied energy will be given.

However, this detected temperature of 50°C actually includes past history.

In other words, 50 degrees Celsius, which has had a record of high profits and is on the way to rising, and conversely, 50 degrees Celsius, which is in the middle of declining temperature.
The range of the detected temperature is different from 0°C.

In this way, the detected temperature includes past history and has different weights, but in the past, these were ignored and the heat generating energy corresponding one-to-one to the detected temperature was sent to the heating element. I was giving it to

As a result, when the temperature is still rising, if documents with a large number of black characters are produced consecutively, the temperature of the entire thermal head will rise rapidly, resulting in immediate overheating.

In addition, there is a difference between the temperature detected by the sensor and the actual temperature of the heating element due to the heat conduction time, so if the detected temperature is used as a reference, it will not record the appropriate heat generation energy. was there.

[Purpose] The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology, and is configured so that overheating does not occur and heat generation energy most suitable for the current temperature of the thermal head can be provided. The purpose of this project is to provide a thermal recording method with

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

Figure 1 and the following diagrams explain one embodiment of the present invention.
A block diagram of the control circuit is shown in the figure.

In FIG. 1, the reference numeral 1 indicates a main control unit on the main body side of a facsimile machine or the like to which a recording unit 5 to which the recording method of the present invention is applied is installed, and in addition to recording control, it also controls reading and transmission 9. Controls all operations such as.

The recording section 5 receives information such as recording mode, line end, page end, etc., and image data from the main control section 1.

The part that receives this information is the recording CPU 2, which transfers the received image data to the thermal head 3.

Further, the thermal head 3 is provided with a temperature sensor 3a such as a thermistor, and the current temperature of the thermal head is read by the recording CPU.

Then, the recording CPU determines the heat generation energy to be applied to the heat generating element according to the detected temperature, and drives the heat generating element via the driver 4.

In principle, the above-mentioned control of the heat generation energy can be performed finely, such as for each line 1"r or several lines, but it is practical to control it for each page of the document.

Next, the operation of this embodiment configured as above will be explained with reference to the flowchart shown in FIG.

In the control example shown in FIG. 2, the width of the pulse applied to the heating element is exemplified as control of the heating energy.

That is, initialization at the time of system startup is performed in step St, and the temperature of the sensor 3a at that time is taken in, and this temperature is set to T.

shall be.

When a command to start recording is received in step S2, the change from temperature To to T1 (T1-To) is added to T in step S3, and the current pulse width is set to T in step S5. Record pages.

This means that, as is clear from Figure 3, if the temperature has increased since the previous time, the temperature T is the actual temperature T! If the temperature has decreased since the previous time, the pulse width should be made longer and smaller than the actual temperature T1.

Then, when one page worth of recording is performed in step S6, this temperature T1 is newly set to T1 in step S7.
o and proceed to the next recording page.

Then, in step S8, the above-described operation is repeated until recording of all the plurality of pages is completed.

In this way, the most appropriate heating energy is applied to the heating element, and recording is performed without causing any inconvenience such as overheating.

In addition, in the above-mentioned embodiment, a method of controlling the pulse width was shown to control the heat generation energy, but the present invention is not limited to this, and a method of controlling the applied voltage value and current value may be adopted.

Furthermore, depending on the position of the temperature sensor and the characteristics of heat conduction, the heat generation energy may be controlled all the time, or it may be selectively controlled only at high temperatures when the temperature of the thermal head changes significantly.

Furthermore, in connection with the pulse width determination method shown in FIG.
The pulse width may be controlled to be suppressed only when 12T o ) becomes (+).

Furthermore, in the above embodiment, the temperature was shifted by adding the temperature change (T1-To) to Tl, but (TI To)
It is also possible to directly adjust the pulse width or to control it by the amount of change in the pulse width.

[Effects] As is clear from the above description, the present invention employs a method of constantly monitoring the temperature of the thermal head and applying appropriate heat generation energy to the heating element.
Accurate recording can be performed without overheating.

Furthermore, in this embodiment, the pulse width is narrower as the rate of temperature rise is higher after recording, and the pulse width is longer as the rate of temperature decrease is higher, so that the heat conduction from the heating element f to the temperature sensor is delayed. can be corrected and heat generation energy suitable for the actual temperature of the heating element can be applied.

[Brief explanation of drawings]

The figures explain one embodiment of the present invention. Fig. 1 is a block diagram of the control circuit, Fig. 7iIJ2 is a flowchart explaining the control operation, and Fig. 3 shows the relationship between the pulse width and the temperature detected by the temperature sensor. FIG. 1... Main control unit 2... Recording CPU3...
Thermal head 3a...Temperature sensor 4...Driver 5...Recording section:,, 'i, f Fig. 1 Fig. 3 Bamboo-misfit 1 comb 4T Fig. 2

Claims (1)

[Claims] In a thermal recording method that controls the heat generation energy supplied to the heating element according to the temperature detected by a temperature sensor installed in the thermal head, the temperature detected by the thermal head during the previous recording is memorized, and the temperature detected by the thermal head during the next recording is stored. A thermal recording method characterized by controlling the supply of heat generating energy to a heat generating element according to the temperature change between the detected temperature and the detected temperature.