JPS61173962A - Thermal recording system - Google Patents

Abstract

PURPOSE:To prevent the generation of overheating and fog or tailing even in a manuscript having a high black area ratio, by detecting the temp. of a thermal head at the point of time when recording was performed until reached the definite number of preset recording lines and correcting heat generating energy corresponding to the detected temp. CONSTITUTION:The main control part of a main body side such as a facsimile apparatus equipped with a recording part 5 performs the control of all operations such as reading, transmission or display other than the control of recording. The 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. A part receiving these informations is a recording CPU2 and transmits the received image data to a thermal head 3. A temp. sensor 3a such as a thermistor is provided to the thermal 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 the detected temp. and drives the heat generating element through a driver 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a thermal recording system, and more particularly to a thermal recording system that controls the heat generation energy of a heating element according to the detected temperature of a temperature sensor provided in a thermal recording head. It is something.

[Prior Art] A thermal recording method is known in which a plurality of heat generating elements supply heat generating energy according to a recording command to the heat generating elements of a standby thermal head to perform recording.

In a recording apparatus employing such a method, a temperature sensor using a thermistor or the like is provided in the thermal head to monitor the temperature of the thermal head.

When the recording system receives a command to start recording, the temperature sensor detects the temperature of the thermal head, determines the heat energy to be applied corresponding to the detected temperature, and records one document in the same state. However, when recording the next document, the temperature of the thermal head is detected again to determine the next heat generation energy.

Control of heat generation energy was usually performed by controlling pulse width.

If such a method is adopted, when recording non-standard long originals with a high black area ratio, the temperature of the thermal head will rise rapidly, causing overheating and fogging and streaks on the recorded image. There was a drawback.

[Purpose] The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional method, and uses an extremely simple method to prevent overheating even for long originals and originals with a high black area ratio.
The object of the present invention is to provide a thermal recording method configured to perform high-quality recording without fogging or trailing.

[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 the main control unit on the main body side of a facsimile machine, etc., to which the recording unit 5 to which the recording method of the present invention is applied is installed, and in addition to recording control, it also performs reading and transmission 9 display. 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.

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

That is, when the apparatus starts, the recording CPU 2 determines in step S1 whether or not a recording start command has been received from the main control section 1.

If a recording command is received, the process advances to step S2, where the number of recorded lines is counted, and the value of Lo is set.

This LO is the number of recording lines that becomes a trigger for controlling the heat generation energy (pulse width).

This value is determined by the performance of the main body of the facsimile machine or the like to which the method of the present invention is applied.

For example, if the facsimile machine is compatible with 84-format recording paper and has a fine mode, the number of recording lines LD is B4 size sub-scanning direction length (383 m) X sub-scanning line density (
7, 7) / Hotoge + α (integer) = 2795, 1 + α'-,
This is the 2795+α line.

If the Lo-2795+α line is used, the heat generation energy will not change in the middle of the document within the standard, and the recording density will not change significantly within one document.

Note that α is set in consideration of adding a header.

The header indicates the function of adding the year, month, date, time, telephone number, or abbreviation to the beginning of the document when recording or transmitting, and indicates when these were recorded.

This header is naturally recorded at the beginning of the copied image or received image, but there are two ways to record it: one is to partially outline the beginning part of the image you want to record, and the other is to add only that amount of information to the beginning. There are other methods.

In the latter case, the received image is longer than the standard 84 format, so +α is required.

Once a certain number of lines LO is set in this manner, the temperature of the thermal head is detected in step S3, and the heat generation energy is determined in accordance with the detected temperature.

Subsequently, in step S4, the image data from the main control section is transferred to the thermal head, and if it is determined in step S5 that the transfer of one line has been completed, the thermal head is driven via the driver 4 in step S6 to perform recording.

When recording for one line is completed, LH-1 is performed sequentially until this value is determined to be 0 in step S7.
Recording for each line is repeated.

When Ll=0, as described above, even if the recording for one original document has not been completed. Since the recording of =2795+α lines has been completed, the process returns to step S2 to perform temperature detection again in order to correct the heat generation energy.

On the other hand, if L is not set to O, enter -t in step S8, and repeat the above-mentioned operations until it is determined in step S9 that recording for one page has been completed. .

If one page is not completed, the process returns to step S4.

If one page is completed, the main control unit is notified in step S10 that one page is completed, and step S10 is executed.
Return to the standby state of step 1.

Note that step SIO notifies the main control unit of the end of the recording operation so that the main control unit can start the next operation such as a cutting operation or a new procedure.

In the above-described embodiment, pulse width control was shown as a method for controlling heat generation energy, but the applied voltage value or current value may be controlled for each fixed line.

In addition, the method of setting the constant number of lines LO is also based on information from the main control unit such as A4/B4. If it is possible to determine standard/fine, etc., a method may be adopted in which the value of the number of sub-scanning lines + α is set each time according to each type.

For example, if the main control unit sends the information "A4. Standard", the recording CPUZ side will print 308m x 3.85ji.
/m+s+α=1178+α and use this value as LO
It's fine if you do this.

When the number of lines of the document being recorded exceeds the Lo line, it is assumed that there is an abnormal situation such as the transmitted document being caught, or that the document is a long document that cannot be compatible, and the number of lines exceeds the Lo line without moving to the next page. All you have to do is detect the temperature and correct the pulse width. The thermal recording method of the present invention can be applied to various recording methods using thermal heads, such as thermal recording, thermal transfer recording, and inkjet recording using a thermal head.

[Effects] As is clear from the above explanation, according to the present invention, the temperature of the thermal head is detected when recording is performed until a predetermined number of recording lines is reached, and the heat generation energy is adjusted accordingly. Since it uses a correction method, it is possible to record high-quality data without overheating or fogging.

Further, since the above-mentioned correction can be performed even within the same page, the recording density does not change significantly during the process.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention; FIG. 1 is a block diagram of a control circuit, and FIG. 2 is a flowchart explaining the control operation. 1... Main control unit 2... Recording CPU3...
・Thermal printer 3a...Temperature sensor 4...Driver 5...Recording unit hanging 1.'' 2nd-

Claims (1)

[Claims] In a thermal recording method that controls the heat generation energy supplied to a heat generating element according to the temperature detected by a temperature sensor provided in a thermal recording head, the number of lines to be recorded under a given condition of heat generation energy is determined in advance, This thermal recording method is characterized in that when recording is performed beyond this number of lines, the temperature of the thermal recording head is detected again, and the heat generation energy is set according to the detected temperature to perform recording.