JPH03230965A - Thermal recorder - Google Patents

Abstract

PURPOSE:To enable high quality thermal recording to be performed by controlling optimum heat history by the use of simple structure by a method wherein a printing correcting means which corrects by energizing a same position of a thermal head following output of a logic means is established. CONSTITUTION:A reference data is read successively from a RAM 4. Data of a former line and a line before the former one are sent to a NOR circuit 39, and a printing data of a present printing line is inputted to one side terminal of an AND circuit 38. Output of the NOR circuit 39 is connected to the other input terminal of an AND circuit 39. A logical product of negation value of a logical add value of printing data to at least two lines before at a same heating dot position of a thermal head 2 and a present printing data value is taken to be sent to SW1. Then, it is sent to the thermal head 2. This data sent to the thermal head 2 becomes a correction data. The thermal head 2 is heated according to the correction data, and one line content heat energy of heat history correction is outputted. Printing of density according to the heating energy is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to, for example, a thermal recording device that performs thermal recording using a thermal head, and relates to a thermal recording device such as a thermal transfer recording device.

[Prior Art] In a thermal recording device that prints using a conventional thermal head, in order to improve printing quality, the heat generation energy of the thermal head is determined while referring to print data of the previous line or surrounding print data. The thermal history control is performed to keep the amount of heat generated by the thermal head constant.

[Problems to be Solved by the Invention] However, in the conventional example, the heat generation amount of the thermal head is varied by comparing the print data of the previous line or the surrounding area, and therefore, there are the following drawbacks.

(1) If an attempt is made to optimize the amount of heat generated by increasing the number of surrounding reference dots, the control circuit becomes complicated.

(2) It may not be possible to appropriately control the amount of heat generated just by comparing with the previous line.

Particularly in the printing of halftone images, it is sufficient for black dots on a white background, but in the case of white dots on a black background, it is necessary to print the surrounding black dots to the desired amount of heat generation. I can't.

(3) In a configuration in which the heat generation amount is controlled by controlling the heat generation time width, the control circuit becomes complicated.

[Means for Solving the Problems] The present invention has been made for the purpose of solving the above-mentioned problems, and includes the following configuration as one means for solving the above-mentioned problems.

That is, the thermal recording device includes a thermal head, a memory that stores print data for at least three dots for printing one dot, and a biasing means that calculates the print data in the memory and biases the thermal head. The energizing means, after printing by the thermal head, calculates the logical sum of the logical sum value of the print data up to at least two lines before the dots at the same position of the thermal head and the current print data value. The apparatus includes logic means for calculating the product, and print correction means for controlling the energization of dots at the same position on the thermal head in accordance with the output of the logic means.

[Operation] With the above configuration, optimal thermal history control can be performed with a simple configuration, and high-quality thermal recording can be performed.

[Example] Hereinafter, an example according to the present invention will be described in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a block configuration diagram of an embodiment according to the present invention. In the figure, 1 is a controller that controls the entire printer of this embodiment, 2 is a thermal head, and 3 is a thermal history control. circuit, 4
stores at least three lines of print data.3
A bit/word RAM, 7 an address circuit for controlling the addresses of the RAM 4, 10 a printing mechanism section including a pulse motor 11 for controlling the conveyance of recording paper, and 15 a host device for outputting print data to the printer of this embodiment. It is. The thermal head 2 is equipped with at least 1942 heating dot elements and a buffer for storing print data for the heating dot elements, and when a heating strobe signal is input, "1" data is stored in the buffer. The device is equipped with a driver section that activates the set heating dot element during the strobe signal period to generate heat.

FIG. 2 shows a detailed configuration of the thermal history control circuit 3 of this embodiment shown in FIG. 1.

In FIG. 2, 3 is the first switch (S Wl), which outputs heat generation control data to the thermal head 2, print line data such as print data, and heat generation control data specific to this embodiment. This is a switch for switching to output reference line data (AND circuit 38 side). 32 to 34 are respectively second switches (SW2);
Third switch (SW3), fourth switch (SW4)
), and in order to generate the reference line data, RA
This is a switch for switching between the current or previous print data from M4. 35 to 37 are a fifth switch (SW5), a sixth switch (SW6), and a seventh switch (SW7), respectively, and print data from the host device 15 can be sent to the RAM4 or written from the RAM4. The read data is transferred to the second switch (SW2) 32, the third switch (SW3) 33, and the fourth switch (SW4).
) 34, 38 is an AND circuit, and 39 is a NOR circuit.

The heat generation control of the thermal head 2 of this embodiment having the above configuration will be explained below with reference to the flowchart of FIG.

First, in step S1, the controller 1 waits to receive a command to start printing one page from the host device 15. When the command to start printing one page is received, the process proceeds to step S2, and the RAM 4 is completely cleared. And the next step S
3, it waits for reception of a print command for printing one line from the host device 15. Upon receiving a print command for printing one line from the host device 15, the controller 1
The control proceeds to step S4, and the address circuit 7 is set to R8T.
Reset with a signal. Next, in step S5, SWI (31) and 5W5 (35) to SW7 of the thermal history control circuit 3 are
(37) The switch corresponding to the RAM bit in which the oldest print data is stored is connected to the host device 15.
Switch to the print data side (print line).

At first, switch 5W5 (35) to the print data side (print line) from the host device 15, then switch SW6 (36) for the next line, then switch SW7 (37), and then switch to SW7 (37) for the next line. Select SW5 (35) again to switch to the print data side (print line) from the host device 15.

Then, in step S6, the RAM 4 is set to write mode by, for example, enabling the WRITE terminal of the RAM 4, and then one line of print data sent from the host device 15 is transferred to the RAM 4 and the thermal head 2.
write into the buffer.

At this time, the clock signal is input to the address circuit 1 and the thermal head 2, and the address of the RAM 4 is counted up and data for one line is sequentially written, and the print data is also sequentially written into the buffer of the thermal head 2. Store.

As a result, preparation for printing out one line of data is completed, and by enabling the strobe signal of the thermal head 2 in step S7, normal printing of one line of print data is performed.

0 The controller l then outputs the R3T signal to the address circuit 7 in step SIO to reset the address circuit 7. Then, in step Sll, 5W1 (31) is switched to the reference line side (AND circuit 38 side), and SW2 (32
) to the readout side of the previous print data of RAM4 (initially the bit 1 side, SW6 side), SW3 (33) to the readout side of the previous print data of RAM4 (initially, the SW6 side, which is the bit 2 side), and SW4 '(34) in RAM
4, the current print data reading side (initially, the SWS side, which is the bit 0 side). Also, step S12
Connect SW5 to SW7 (35 to 37) to the RAM4 side and switch to take out the reference line.

The controller 1 outputs a clock signal for one line to the address circuit 7 and the thermal head 2 in step S13. When the address circuit 7 receives a clock signal, it sequentially counts up the addresses of the RAM. For this reason,
The reference data is sequentially read from the RAM 4, and the data of the previous line and the line before the previous line are sent to the NOR circuit 39, and the current (
The print data of the print line (just before) is output to the AND circuit 38.
is input to one terminal of The output of the NOR circuit 39 is connected to the other input terminal of the AND circuit 39, and at least two
The logical product of the logical sum value of the print data up to the front of the line and the current print data value is taken and SWI (31)
sent to.

Then, it is sent to the thermal head 2. This is performed for one line of data for each clock signal. The data sent to this thermal head 2 becomes correction data.

When the transfer of one line of correction data is completed, in step S14, the strobe signal of the thermal head 2 is enabled to cause the thermal head 2 to generate heat according to the correction data, and thermal energy for one line of thermal history correction is output. Print output is performed at a density according to the heat generation energy. At this time, the feed control of the recording paper via the print mechanism 10 is not performed, and printing is performed in accordance with the correction data at the same print position as the previous print position.

In step S15, it is determined whether or not one page's worth of print output has been completed. If the one page's worth of print output has not been completed, the process advances to step S16, and for example, the pulse motor 11 of the print mechanism section 10 is driven. The recording paper is fed by one line in the same manner. Then, the process returns to step S3 and moves to the printing process for the next line.

In the printing process for the next line, SW5 (35), 5W6 (36) and SW5 (35), 5W6 (36) and
7 (37), bit 2 of RAM 4 is the previous line, bit O is the previous line, and bit 1 is the print line.

Therefore, in step Sll, SW2 (32) is placed on the SWT side, which is the bit 2 side, and SW3 (33) is placed on the bit O side.
SW4 (34) is switched to the SWS side, which is the bit 1 side, and the SWB side, which is the bit 1 side.

Thereafter, the print line and the reference line are switched one after another, and print output is executed by thermal history control.

When the printout for one page is completed, the process advances to step S17, where the process of discharging the recording paper for one page is performed, and the process of supplying the recording paper of the next page to the thermal head 2 position 4 is performed, and the process returns to step S1. Prepare for printing the next page.

FIG. 4 shows the relationship between print data and history data recorded on the same line through the above process. In FIG. 4, when the print data is white, it is O (low level) in FIG. 2, and when it is black, it is l (high level).

In FIG. 4, T1 indicates the heat generation timing (printing) on the print line, and T2 indicates the heat generation timing of correction data on the reference line.

Only when the level print data (current line) is black (with data) and the dots at the same position on the previous line or two lines before are black, the correction data becomes the print mode (heating mode) according to the embodiment.

As explained above, according to this embodiment, the comparison and calculation is made with at least two reference lines, and the same line is printed separately as print data and history data, so the simple configuration allows optimal thermal history control. This enables high-quality thermal recording.

Particularly in halftone printing, when the black rate is high, the printing energy is reduced, the white reproducibility is good, and the reproducibility of the halftone gradation of the printed image is improved.

Second Embodiment] The above explanation is based on the N'OR of the thermal history control circuit 3 shown in FIG.
Although an example has been described in which SW2 to SW4 are used to switch input signals to the circuit 39 and the AND circuit 38, similar switching control can be performed using a shift register instead of the switches. FIG. 5 shows the configuration of a thermal history control circuit in which a shift register is used in place of the switches SW2 to SW4 to perform similar switching control.

In Figure 5, the same components as in Figure 2 are designated by the same numbers (-=
tL, detailed explanation will be omitted.

In the second embodiment, 5W5 (35) to 5W7 (37
) is connected to a 3-bit shift register 51.

By adopting the configuration shown in FIG. 5, step S1 of the first embodiment. ], change to the switch switching control, and change the RAM4
Set the reference line data in the shift register 51 and read the reference line data. Control is performed to output a shift signal so that the manual input to the &NOR circuit 39 becomes the print data of the previous and previous print data, and the input to one input terminal of the AND circuit 38 becomes the current print data.

In the above embodiments, wiring to each switch as in the first embodiment is required (and the switching control can be made simple by simply outputting the required number of shift signals. Is the configuration simple? 7.It also makes the implementation design easy.

[Third Embodiment] In the above example, a 1 word/3 dot RAM is used, and each dot is assigned to the current print data, the previous print data, and the print data from the time before the previous time. The invention is not limited to the above example, but can also be constructed with three 1-bit/1-word RAMs each storing one line of print data. FIG. 6 shows an example in which the RAM is constituted by three 1-pill/1-word RAMs each storing 1 line of print data. In FIG. 6, the same components as in FIG. 1 are given the same numbers, and detailed explanations are omitted.

In FIG. 6, three 1-bit/1-word ARAMs 4a and 13RAMs 4b each store one line of print data as RAMs.

It is composed of CRAM4c.

In this embodiment, the configuration of the thermal history control circuit 2 may be the same as the thermal history control circuit of the first embodiment described above, or the same configuration as the thermal history control circuit of the second embodiment. It may be.

And SW5 (35) to 5W7 (of each thermal history control circuit)
37) input to RAM4 (not D bits o~2,
AR, AM4a, BRAM4b, CRAM4c respectively
data lines will be connected.

The switch connection switching control to each of the RAMs 4a to 4c is changed to the connection switching to bits 0 to 2 of the RAM 4 in the above embodiment, and is controlled by the ARAM 4a'.

It is sufficient to control switching to the data line of BRAM4b and CRAM4c.

Although each of the above explanations has been made regarding a thermal recording device, the present invention can also be applied to thermal recording devices such as a thermal transfer recording device using an ink sheet or a sublimation type recording device. It goes without saying that the present invention is not limited to the type with heating dots, but can also be applied to an oscillating one-line/multi-dot heating type or a scanning type.

Furthermore, the thermal history is not limited to three lines;
It may be for four lines or more. In this case, corrective heat generation control may be performed based on the past number of heat generation lines.

[Effects of the Invention] As described above, according to the present invention, optimal thermal history control is possible with a simple configuration, and high-quality thermal recording is possible.

0 Particularly in halftone printing, the printing energy is reduced when the black rate is high, and the white reproducibility is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the first embodiment according to the present invention, FIG. 2 is a detailed configuration diagram of the thermal history control circuit shown in FIG. 1, FIG. 3 is a print control flowchart in the first embodiment, and FIG. 4 is a diagram showing the relationship between print data and history data recorded on the same line, FIG. 5 is a detailed configuration diagram of the thermal history circuit of the second embodiment according to the present invention, and FIG. 6 is a diagram showing the third embodiment according to the present invention. FIG. 2 is an example block diagram. 1 In the figure, 1... Controller, 2... Thermal head, 3... Thermal history control circuit, 4... RAM, 7...
Address circuit, 10... To printer 1 Mechanism section, 11...
・Pulse motor, 15...Host device, 31 to 37・
... Selector switch, 38... AND circuit, 39...
-NOR circuit, 51...shift register. 2 Figure 6 462

Claims (3)

[Claims] (1) A thermal head, a memory that stores print data for at least three dots for printing one dot, and an urging means that calculates the print data in the memory and urges the thermal head. In the recording device, the biasing means is configured to apply at least two pressures at the same position of the thermal head after printing is performed by the thermal head.
a logical means for logically multiplying the logical sum value of the print data up to the front of the line and the current print data value; and a print correction means for controlling the energization of the same position of the thermal head according to the output of the logical means. A thermal recording device comprising: (2) The thermal head according to claim 1, wherein the memory stores data for three lines as one word for one dot of the thermal head, and the logic means calculates the line data in units of one dot. Recording device. (3) Memory stores print data in the order of past prints.
Consists of three line storage memories that store data for each line.
2. The thermal recording device according to claim 1, wherein the logic means calculates the line data dot by dot.