JPS62176266A - Thermal recording device - Google Patents

Abstract

PURPOSE:To suitably control the heating quantity of a recording head by counting a time interval and the number of recording driving data recorded for respective blocks of a recording element and controlling a heating driving quantity recorded in accordance with the result. CONSTITUTION:A data input part 2 receives reading data, receiving image data, etc., from a reading part 10 or a communicating part 11 composed of MODEM NCU, etc., and inputs them to a main control part 1. The recording control of a thermal head 3 is executed by a recording part CPU 4 and a driver circuit 5. The recording part CPU 4, when the thermal head 3 is driven based on the recording data given from the main control part 1, controls the recording driving quantity (driving voltage transformation, time and number of driving pulse) of the thermal head 3 through the driver circuit 5 and controls the heating quantity. The control is executed for a recording block, and executed based on the time interval of the recording for a block and the number of the recording driving data (black dot).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal recording device, and particularly to a thermal recording device such as a thermal printer or a thermal transfer printer that performs recording using heat as a medium.

[Prior Art] This type of recording device has been widely used in recent years because of its low operating noise and simple structure. In particular, many facsimile machines, which have become popular in recent years, employ this type of device as a recording/output device.

Thermal recording devices used in facsimile machines, etc.
A thermal printer (hereinafter referred to as a thermal printer) has 1000 heating elements.
Most devices use linear recording heads arranged in a straight line over the entire recording width of about 2,000 mm, and many devices use thermal paper.

[Problems to be Solved by the Invention] As is well known, in this type of device, it is important to control heat generation by taking heat accumulation in the recording head into consideration in order to maintain high recording quality. There is. Therefore, methods such as providing a temperature detection means such as a thermistor in the recording head and controlling the amount of heat generation drive according to the detection output, or controlling heat generation according to the number of black dots (recorded dots) in the recorded data, etc. However, the conventional method still sometimes causes deterioration in recording quality such as unevenness in recording density.

For example, in the above-mentioned thermal printer for facsimile machines, after the main controller decodes the received image data from a format such as MH or MR code.

In order to receive and record this decoded data,
There was a problem in that the recording time interval for each line was not constant, and (1) the amount of heat dissipated from the head for each line varied, resulting in uneven recording density.

In addition, in the conventional method of controlling the amount of heat generation drive based on the number of recording dots in the recorded data, the determined amount of heat generation drive is applied to the entire head. If there was a deviation of 41 dots, unevenness in the t2 density could occur.

[Means for Solving the Problems] In order to solve the above-mentioned problems, according to the present invention, in a thermal recording device having the Q element consisting of a plurality of heating resistors divided into a plurality of blocks, the recording element is 4 means for specifying the time interval for each unit of recording performed using the method;
It has a means for counting the number of recording drive data for each block of the recording element, and heat generation drive of the recording element according to the time interval measured by the measuring means and the number of drive data counted by the counting means. A configuration was adopted in which the amount was controlled for each block.

[Function] According to the configuration of L below, recording 1, such as a facsimile machine, etc.
Even when recording output is performed by a device with variations in 1J1 intervals, the amount of heat generated by the recording head can be appropriately controlled, and even if there is a bias in the recording drive data in one unit of recording data, it can be corrected appropriately. becomes possible.

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

FIG. 1 shows a thermal printer for a facsimile machine as an embodiment of the thermal printer according to the present invention, and the structure of the entire facsimile machine including the thermal printer. 1 communication, record.

This is the main control unit for controlling all operations such as display, and is composed of a microcomputer and memory elements such as ROM and RAM. The data input 81!2 inputs read image data, received image data to be recorded, etc. to the reading unit 10 and the communication unit 1 which includes a modem, NCU, etc.
1 and inputs it to the main control unit l.

Here, 204 is used as a recording head of a thermal printer.
A thermal head 3 is provided in which this number of heat-generating resistors are arranged across the width of recording paper (thermal paper) so that eight dots can be recorded. The thermal head 3 includes a thermistor 6 as a temperature detection means to detect the state of heat accumulation.
is installed.

Recording control of the thermal head 3 is performed by a recording unit CPU 4 and a driver circuit 5. When the recording unit CPU 4 drives the thermal head 3 based on recording data given from the main control unit l, the recording unit CPU 4 drives the thermal head 3 via a driver circuit 5 consisting of a switching transistor, a known driver element, a shift register, a latch element, etc. The amount of heat generated by the thermal head is controlled by controlling predetermined parameters among the recording drive amount, ie, drive time of the heating element, drive voltage, number of drive pulses, etc. In the case of this embodiment, the amount of heat generated at this time corresponds to the recording time interval for each line (in this embodiment, it corresponds to the decoding time of encoded data in the facsimile machine. In some cases, the time for communication is also included. ) Control is performed based on the number of recording drive data (black dots) for each block of the heating resistor of the thermal head 3 divided as described later and the temperature detected by the thermistor 6 attached to the thermal head 3.

FIG. 2 shows an embodiment of the thermal head 3 and driver circuit 5 shown in FIG. 1. As shown, the thermal head 3 is composed of 2048 heating resistors of R1 to R2048. These heating resistors R1-R204B
is divided into four blocks of 512 blocks each, each of which is connected to driver elements 51 to 54 each consisting of the same number of switching means such as transistors. Driver element 51~
54 are strobed by strobe signals 5TBO to 5TB3, respectively. Therefore, resistors R1 to R2048
are not driven all at once, but are divided into 512 parts and driven.

Such a configuration is useful for reducing instantaneous power consumption.

Further, the recording data given to the driver elements 51 to 54 is stored in the latch 55. That is, the recording CP
1 in serial format input from U or main control unit l
The recording data for each line is sequentially stored in the shift register 56 in synchronization with the clock CLK, and when the recording data for 2048 dots is collected in the shift register 56,
By inputting a latch signal, recording data is held in the latch 55 as parallel data. By this latching operation, the control input corresponding to each resistor of driver elements 51 to 54 is changed according to the data, and preparations are made for simultaneous energization of each block by strobe signals 5TBO to 5TB3.

Next, the operation of the above configuration will be explained.

Figures 3 and 4 show the main control unit l and the recording unit CPU4, respectively.
FIG. 2 is a flowchart showing a recording control procedure. Third
The procedures shown in FIGS. 4 and 4 are stored as a control program in a storage means such as a ROM (not shown).

In step SlO in FIG. 3, the main control unit l determines whether image data received via the communication unit 11 (or read by the reading unit (in the case of a copy operation)) is input to the data input unit 2. , if there is data input, the process moves to step 520.

At step 320, the main control unit l decodes the input image data from a format such as MH or MR code.

Then, the black rate of the data decoded in step S30,
That is, the ratio of data for recording and driving the heating resistors is measured for each of the four blocks of the heating resistors. Here, since the total number of elements in each block is constant, specifically, it is only necessary to count the number of each recording drive data in the block.

Next, in step S40, the decoded recording data is transferred to the shift register 56 of the driver circuit 5 in FIG. 2 in synchronization with the clock CLK.

The operations in steps 510 to 340 above are performed in step S5.
0, the process is repeated until it is confirmed whether data transfer for one line of 2048 dots has been completed.

When the data for 1947 minutes have been stored in the shift register 56, the state of the flag FO is determined in step S60. The flag FO is reset by the recording unit CPU 41 as described later, and it is determined whether the recording of the data for 1947 minutes has been completed. It shows whether or not it is. That is, unless the flag FO is reset (=0), the next line cannot be recorded, so the process waits in step 360.

Once the flag FO has been reset, the process moves to step 370.
The data of the next line is transferred to the latch 55 and held there.

That is, a latch signal is input to the latch 55.

Then, in step S80, a recording command is sent to the recording unit CPU4, and in step S90, a recording command is sent to the recording unit CPU4.
The number of recording drive data for each block of the thermal head 3 counted in step 30 is also given to the recording unit CPU 4.

On the other hand, the command in step S80 is
4, detected in step 3100 of FIG. When the recording unit CPU 4 receives the recording command, it executes step 311.
0 and stops the timer that has been started as described below. This timer is for measuring the time interval from the end of recording to the input of the next command, that is, the time required for data decoding, etc., and is composed of a hardware element (not shown) or software of the CPU 4, etc.

Subsequently, in step 5115, the amount of heat generation of the thermal head 3 is controlled for each block. That is, here, the drive amount (drive time, drive voltage, etc., but hereinafter referred to as drive time) for generating heat for each block is calculated based on the number of recording drive data for each block transferred in the Fmm step 590. At the same time, the driving time of each block is corrected based on the count value of the timer stopped in step 5ilo. Specifically, in a block in which many resistors are driven for recording, the driving time is extended compared to the standard value. This is to compensate for the decrease in the amount of heat generated due to the decrease in the current value of each heating resistor. Further, when the count value of the timer is large and the line recording cycle is long, the driving time is extended to compensate for the decrease in the amount of heat storage due to heat radiation from the head. Conversely, when the recording cycle is short, the driving time is shortened to prevent overheating of νF.

Subsequently, in step 5120, the recording unit CPU 4 sets a flag FO (=1) to prohibit input of new data during the recording operation.

Furthermore, in step 5130, the detected value of the thermistor 6 is read, and based on this, the drive time of each block of the thermal head 3 is finally corrected. As with the conventional method, the correction method here is to adjust the drive time of each block by a predetermined amount (or at a predetermined ratio) when the thermal head is overheated.
It shall be shortened.

Then, in step 5140, strobe signals 5TBO to 5TB3 are turned on for the finally determined drive time,
Latch 5 the heating resistor of each block of thermal head 3.
Power is applied based on the data given in 5.

Subsequently, in step 5150, the end of recording is detected by checking whether the energization of the resistor in step 5140 has ended. When the end of recording is detected, step 51
At step 60, the flag FO is reset to permit the main control unit l to input data for the next line.

Subsequently, in step 5170, a timer is started to measure the time interval until the next line recording command. Note that the start and stop timings of the timer are not limited to those described above, and the recording period including the recording time may be measured by performing stop->start in step Sl10.

According to the above configuration, since the drive amount is corrected for each block of the thermal head 3 according to the number of recording drive data, (1) deterioration of recording quality such as one-degree unevenness within a line will not occur; Since the drive amount is corrected according to the recording time interval for each line, even if there are variations in the data decoding time of the main controller l, there will be no density drop due to heat radiation from the head. Since the head temperature is corrected by the thermistor 6, there is no damage caused by over-ripening of the head or deterioration of recording quality.

Although a thermal printer for a facsimile machine has been described as an embodiment, it goes without saying that the present invention can be practiced in other types of thermal printers, such as thermal transfer printers using ink ribbons. Furthermore, in the two-legged embodiment, a one-dimensional array line type thermal head was illustrated.

The technique described above can also be applied to a device using a two-dimensional array of thermal heads or a Ghent scanning type thermal printer.

[Effects] As is clear from the above description, according to the present invention, in a thermal recording device having a recording element consisting of a plurality of heat generating resistors divided into a plurality of blocks, one unit of recording is performed using the recording element. It has means for measuring the time interval for each recording, and means for counting the number of recording drive data for each block of the recording element, and the time interval measured by the measuring means and the number of recording drive data counted by the counting means. Since a configuration is adopted in which the amount of heat generated by the recording element is controlled for each block according to the number of drive data, the recording can be performed stably regardless of variations in the recording interval or unevenness of the recording data in one unit of recording data. It is possible to provide an excellent thermal recording device that can obtain high recording quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of a thermal printer for a facsimile machine as an embodiment of the thermal recording device according to the present invention, FIG. 2 is a block diagram showing the structure of the dryer circuit shown in FIG. 1, and FIG. , and FIG. 4 are flowcharts 1 showing the recording control procedure of the main control unit and foot odor CPU of FIG. 1, respectively. l...Main control section? ...Data input section 3...
- Thermal head 4... Recording unit CPU5... Driver circuit 6... Thermistors 51-54... Driver element 55... Latch 56... Soft register I
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Claims (1)

[Claims] In a thermal recording device having a recording element consisting of a plurality of heating resistors divided into a plurality of blocks, means for measuring a time interval for each unit of recording performed using the recording element, and recording for each block of the recording element. It has means for counting the number of driving data, and controls the amount of heat generated by the recording element for each block according to the time interval measured by the measuring means and the number of driving data counted by the counting means. A thermal recording device characterized by: