JPS63154372A - Thermal recorder - Google Patents

Abstract

PURPOSE:To prevent ununiform printing or generation of voids in printed images, while contriving a reduction in power consumption and a higher printing speed, by sending heat pulses again based on printing data to heat generating elements located at an end part of a printing block used for printing, at the time of printing by a subsequent block. CONSTITUTION:With an input image information (a) inputted to a thermal recording controller 1, the image information d1 for a first block is outputted. When printing by the first block is completed, printing by a second block is started, and an applied pulse signal (b) is brought to an H level, whereby image information d2 for the second block is printed following the image information d1 printed by the first block. In this case, last bit data is printed twice at the same position. In one-time printing, ununiform printing or generation of voids in printed images may occur due to insufficient heating of heat generating elements 7. However, when the same picture element data is again printed at the same position, printing time for the data is doubled, resulting in that ununiform printing or generation of voids in the printed images can be prevented from occurring at an end part of the first block.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a thermal recording device, and more particularly,
A thermal recording device in which a line of information is divided and printing of one line is completed in multiple printing operations, which achieves uniform recording density for printing located at the end of the divided information. Regarding equipment. (Prior Art) Recently, there has been a desire to downsize recording devices, and in response to this demand, thermal recording devices that utilize heating elements, such as thermal recording devices that utilize thermal elements, have been developed. Such a thermal recording device generally includes heating elements corresponding to the number of pixels for one line in the main scanning direction, and prints on a line-by-line basis. However, when printing one line, the number of heating elements that can be driven simultaneously may be limited due to the power supply capacity. Therefore, conventionally, the heating element of a thermal head is divided into a plurality of blocks, and printing is performed for each block. (Problems to be Solved by the Invention) However, in such a conventional thermal recording device, printing for one line is divided into blocks, and therefore, it is difficult to print in close proximity to elements that are not heated. There is a problem in that the edges of each block are not heated to a sufficient temperature, resulting in uneven printing or white spots (no printing) in these areas. On the other hand, as a solution to such problems, there is a method described in, for example, Japanese Patent Application Laid-open No. 145325/1983. In the method described in this publication, the pulse width of the heat pulse sent to the heating elements located at both ends of the divided block is increased to increase the amount of heat generated. Prevents white fading. However, even with such a device, the number of divided blocks is fixed and the width of the heat pulse to the heating elements located at both ends of each block is lengthened, so the normal pulse width time is Compared to printing, power consumption is higher and printing time is longer. For this reason, it is not only difficult to reduce power consumption, but also a new problem arises in that the printing speed becomes slow. (Object of the Invention) Therefore, the present invention has an object of dividing print data into blocks and sequentially printing each block, and when printing subsequent blocks, a heating element located at the end of the print block in the printing method is set based on the print data. By sending out a heat pulse again and printing, the end of the printing block can be printed multiple times, with the aim of reducing power consumption and increasing printing speed while preventing uneven printing and white spots. There is. (Structure of the Invention) In order to achieve the above object, the present invention provides a thermal recording device that prints by sending heat pulses to heating elements arranged in a row based on print data, in which the print data is divided into a plurality of blocks. a dividing means for dividing the blocks into blocks; a driving means for sequentially sending out heat pulses for each block to heating elements corresponding to the divided data; and a heating element corresponding to the printing data based on the printing data located at the end of the block. and an end element driving means for sending out a heat pulse when printing a subsequent block. Hereinafter, the present invention will be specifically explained based on examples. 1 to 3 are diagrams showing one embodiment of the present invention, which is applied to a facsimile machine. First, the configuration will be explained. In FIG. 1, ■ is a thermal recording control device, and the thermal recording control device 1 includes a black detector 2, a counter group 3, a timer 4,
It is composed of a controller 5. On the other hand, 6 is a one-dimensional thermal head with a built-in drive circuit, and the thermal head 6 is composed of a heating element 7, a data gate 8, a latch 9, and a shift register 10. The thermal recording control device 1 includes input image information (a) stored in a memory (not shown).
is input, and the thermal recording control device 1 performs a predetermined operation based on the input image information (a) and outputs an applied pulse signal (b), a latch signal (C), and print data (d,) to the thermal head 6. The thermal head 6 receives these signals and performs predetermined printing. In the thermal recording control device 1, the black detector 2 determines the color of the input image information (a), that is, the black data included in the input image information @(a), and outputs the result to the controller 5. The black detector 2 has a function as a dividing means for dividing input image information (a) into a plurality of blocks. controller 5
For example, it is made up of a microcomputer, and although not shown, it is equipped with CPU ROM5RA, M, I10 boards, etc. The CPU is equipped with a register group consisting of a plurality of registers, such as a LINE END register that indicates the end of transmission of one line of print data, and a previous dummy end F (flag) register that indicates the end of transmission of previous dummy data, which will be described later. It also has a storage register and the like for storing block end data (last bit data) of the input image information <a> divided into the plurality of blocks described above. The controller 5 outputs the determination result of the black detector 2, the number of data of input image information (a), etc. to the counter group 3, and reads out the count value of the counter group 3 as necessary. The counter group 3 is composed of a plurality of counters, and includes, for example, input image information (a
), a send-out data counter that counts the number of data of the input image information (a) divided into a plurality of blocks, and the respective data numbers of front dummy data and rear dummy data, which will be described later. It has a front dummy counter and a rear dummy counter etc. for setting. The controller 5 outputs control signals to the black detector 2 and timer 4, and also outputs the latch signal (C) and print data (d) to the latch 9 of the thermal head 6 and the shift register 10, respectively. The timer 4 determines the pulse width of the applied pulse signal based on the control signal from the controller 5 and outputs it to the data gate 8 of the thermal head 6. In the thermal head 6, a shift register 10 sequentially reads input print data (d) (serial data) according to a clock signal (not shown),
When one line of data is read, it is converted into parallel data and output to the latch 9. The latch 9 holds the input parallel data according to the latch signal CG> and outputs it to one input terminal of the data gate 8. data gate 8
The applied pulse signal (b) from the timer 4 is input to the other input terminal of the data gate 8, and the data gate 8 outputs a heat pulse to the heating element 7 according to the applied pulse signal (C) and parallel data from the latch 9. do. The heating element 7 generates heat in response to the heat pulse, and prints on a predetermined thermal paper (not shown). The data gate 8, the latch 9, and the shift register 10 function as driving means for sequentially sending heat pulses to the heating element 7 for each block, which corresponds to the input image information (a) divided into a plurality of blocks. Further, the thermal recording control device 1, the data gate 8, the latch 9, and the shift register 10 function as end element driving means, and a detailed explanation thereof will be given later. Next, in Figure 2 explaining the operation, the figure shows one line of print data (d).
3 is a timing chart showing the relationship between the applied pulse signal (b) and the print data (d) when the image information is divided into three pieces of image information (dl), (d2), and (d3) and printed. When the input image information (a) is input to the thermal recording control device 1, the image information (dl) of the first block is sent out. In the thermal recording control device 1, the number of black pixels included in the input image information (a) is counted by a black number counter provided in the counter group 3, and the number of black pixels reaches a predetermined limit number determined by the power supply capacity. When the image information (dl) is reached, the transmission of the image information (dl) is stopped. At this time, the final bit data of the image information (dl) is stored, and from then on, the controller 5 uses white data (hereinafter referred to as post-dummy data (DIN)) until the total number of data transmitted in the first block reaches the number of pixels for one line. ) is sent. The sent print data (d), that is, the image information (
dl) and post-dummy data (DIN) are held by latch 9 in accordance with a latch signal (C), not shown. 1547 minutes of print data held by latch 9 (d
) is printed when the applied pulse signal (b) becomes H level, but what is actually printed is the dummy data (DIR).
) is the image information (di) excluding the image information (di). When the printing of the first block is completed, the printing of the second block starts, but at this time, the image information sent out in the first block
White data (1 data less than the data number of I(di))
The previous dummy data (hereinafter referred to as D. r) is first sent out. Previous dummy data (Da
When the transmission of y) is completed, the first
The last bit data of the image information (di) stored in the block is sent out, and then the image information (d2) of the second block is sent out. The image information (d2) is the image information of the first block (
dl), the number of data is limited by the limited number of black pixels, and the final bit data is stored as in the first block. Thereafter, similar to the first block, the second dummy data (DIN) is sent out until the total number of print data (d) of the second block reaches the number of pixels for one line, and the applied pulse signal (b) becomes H level. Then, the image information (d2) of the second block is printed following the image information (dl) printed in the first block. At this time, the number of data in the previous dummy data (D * r) of the second block is equal to the image information (dl
), and the last bit data of the image information (dl) of the first block is printed next to the previous dummy data (D!F), so this last bit data is printed at the same position. Printed twice. Therefore, in one printing, the end of the block adjacent to the heating element 7 corresponding to the first data of the second block, that is, the heating element 7 corresponding to the last data of the first block, is not sufficiently heated. As a result, uneven printing and white spots occur, but this is equivalent to lengthening (doubling) the printing time by printing the same pixel data at the same position again, even though the temperature of the heating element 7 is not sufficient. Effects can be obtained. As a result, uneven printing and white spots at the end of the first print are prevented. Furthermore, when printing the second block, the last bit data of the first block becomes the first data of the second block, so the heating element 7 corresponding to the original first data of the second block is heated to a sufficient temperature. , uneven printing or white spots do not occur in the first data of the second block. When the sending of the rear dummy data (D
Previous dummy data (D3F) with less data is sent. Next, although not shown, the final bit data of the image information (d2) stored in the second block is sent out, and then the image information (d3) of the third block is sent out. Thereafter, image information (d2) is obtained in the same manner as for the first and second blocks.
The final bit data of is printed twice at the same position, and subsequently the image information (d3) of the third block is printed. Therefore, in the same manner as when printing the second block, the final bit data of the second block is printed twice at the same position, thereby preventing uneven printing and white spots. Thereafter, the next line is printed in the same manner. FIG. 3 is a flowchart showing a program for thermal recording control, and the printing operation shown in FIG. 2 will be explained according to the flowchart. First, printing of the first block will be explained. LINE END in controller 5 at step P
It is determined whether the register is [1] or (0), but when printing the first block, LINE END = 1, and 1
It is determined that printing for the line has been completed, that is, printing for the input image information (a) for one previous line has been completed, and the process proceeds to step P. At step P2, the LINE END register is set to (0).
is set, and the process proceeds to step P. In step P, the previous dummy end F (flag) in the controller 5 is set to [1].

[0]. When printing the first block, the previous dummy data is not sent, so it is [previous dummy end F-0], and the process advances to step P. In step P, the sending data counter is cleared and the process proceeds to step P9, and in step P, data, that is, input image information (a) is read. Proceed to. In step P1゜, it is determined whether the read data is white or black, and if it is white, the step pH is
The program jumps to step peg and outputs the data read in step P9 as image information (dl). on the other hand,
If it is black, the black number counter is incremented by 1 at step pH, and the process proceeds to step P1□, where the data is output as image information (dl). Then, step Plf
At step f, the sending data counter is incremented by 1, and the process proceeds to step PI4. In step P14, it is determined whether the value of the sending data counter matches the number of pixels for one line. Since there is no failure when printing the first block, it is determined at step PUS whether the value of the black number counter matches the predetermined black number limit value determined by the power supply capacity, and if it does not match, Steps P to PUS are repeatedly executed until the black number is limited. When the black number limit value is reached, the process proceeds to step pta, where the black number counter is reset, and the process proceeds to step Pl. In step PI, a value obtained by decrementing the value of the sending data counter by 1 is set in the previous dummy counter, that is, a value obtained by subtracting the last bit data, and the process proceeds to step pH. At step pts, the dummy counter is set to [the number of pixels for one line - the sending data counter value], and the process proceeds to step PI9. In step P19, step p+ is stored in the storage register.
Set the data output at step z, that is, the final bit data of the image information (dl), and proceed to step P2! Proceed to step pgz, whether the LINE END register is [1] or [
0], and the determination is made in the same manner as in step P1. 1st
When printing blocks, press LINE END in step P2.
to the register

Since [0] is set, step pts
Proceed to step P2. Then, one pixel worth of rear dummy data (rear dummy data D+*) is sent. Next, in step Pta, the value of the post-dummy counter is decremented by 1.

Determine whether it is [0] or not, and
] Each step pzs and Pt4 are repeatedly executed until the result is reached. The value obtained by decrementing the value of the dummy counter by 1 is

When it becomes [0], the process proceeds to step pts, generates the latch signal (c) mentioned above, and proceeds to step PR&. In step P0, the memory pulse value for setting the pulse width of the applied pulse signal (b) is written to the timer 4. , prints the first block. Next, printing of the second block will be explained. When the printing of the first block is completed, the LINE END register is set in the previous step Pz as mentioned above.

Since [0] is set, the process advances from step P to step P3. In step P3, the previous dummy data for one pixel (previous dummy data D□) is sent out, and the process proceeds to step P4.
, then the value obtained by decrementing the value of the previous dummy counter by 1 is

[0] or not, and the value obtained by decrementing the value of the previous dummy counter by 1 is

Each step Ps and P4 is repeatedly executed until the value becomes [0]. The value obtained by decrementing the previous dummy counter value by 1 is

When the value becomes [0], the process proceeds to step P, where it places [1] in the previous dummy end F register and proceeds to step P. In step P, the determination is made as described above, and the previous dummy ends. F
= 1, so proceed to step P. In step P7, the last bit data of the image information (dl) stored in step P19 during printing of the first block is sent out from the storage register. Next, each step P, pts is processed in the same way as when printing the first block, and each step P, pts is processed until 1947 minutes of data transmission is completed or the value of the black number counter reaches the black number limit value. ~ Repeat PIS. When printing the second block, the number of sent data is less than the number of pixels in one line, so when the value of the black number counter reaches the limit value, each step PI&~pzi is executed as before, and the second block is printed.
Sending block print data (d), latch signal (C)
The generation of and the setting of the recording pulse value to the timer are completed. Finally, the third block will be explained. When the sending of the print data (d) of the second block is finished, the same LINE as last time is displayed.
The END register is

Since [0] remains set, perform the same processing as described above in each step from step P to step P, send out the previous dummy data (D3F), and set [1] to the previous dummy end F. 0 then,
Same as last time, each step P6~. Proceed to step pus via -. Furthermore, in step pus, the same determination as last time is made and each step P, ~ PIS is repeated, and step PI4
When the value of the sending data counter reaches the number of pixels for one line, (1) is set in the LINE END register at step P2°, and the process proceeds to step PH1. Step P
In □, go to the previous dummy end F register.

Set [0] to prepare for printing the next line. Finally, in step pzt, the same determination as last time is made [LI
NE END=1), so each step pzs,
After passing through pza, printing of the third block is completed. In this way, one line of printing is divided into three blocks, and when the next block is printed, the last bit data of the image information rIv1 (di) or (d2) of the previous block is again at the same position. is printed on. That is, after printing the first block's image information (dl) or the second block's image information (d2), when printing the next block, the previous dummy data, which is one data less than the number of data of these image information, is first sent out, and then stored. Since the final bit data of the previous image information stored in the register is sent out, the final bit data of the previous block will be printed twice at the same position. Therefore, it is possible to always set the heating time of all the heating elements 7 to be the same and to obtain sufficient color development at the end of the block. As a result, uneven printing and white spots can be prevented while reducing power consumption and increasing printing speed. In this embodiment, a case has been described in which one line is divided into three blocks and printed, but it is not necessarily divided into three blocks. That is, since one block is determined by the number of black pixels of print data with respect to an unlimited value, it may be two blocks or one block. Therefore, the print data can be divided according to the content of the print data, and the printing speed can be further improved while always supplying sufficient power to the heating element 7. Further, in this embodiment, printing is performed twice for one end of each block, but the present invention is not limited to this. For example, when sending print data of the first block, the first bit of the image information (dl) Send data, then send dummy data to form the first block (i.e. 1 pixel)
is printed. Next, the image information of the second block may be printed in the same manner as in the embodiment, and after the printing of the final block is completed, the final bit data of the final block may be printed again. In this way, ■2 pixels at both ends of the line.
By configuring the printer to perform printing at the same time, it is possible to prevent uneven printing and white spots on both ends of each line, and to further improve printing quality. Further, in this embodiment, the last bit data of the previous block is printed again when printing the next block, but the present invention is not limited to this. In short, it is sufficient to print a plurality of times, so it is also possible to configure a configuration in which printing is performed for the third time when printing the third block. In addition, in this embodiment, the thermal recording device is applied to a facsimile machine, but it goes without saying that the present invention can also be applied to devices other than facsimile machines that apply thermal recording, such as printers. (Effects) According to the present invention, when printing a subsequent block, a heat pulse is sent again to the heating element located at the end of the previous printing block based on the print data, so that printing is performed at the end of the block. This can be performed multiple times, and it is possible to prevent uneven printing and white spots while reducing power consumption and increasing printing speed. As a result, printing quality can be further improved.

[Brief explanation of the drawing]

1 to 3 are diagrams showing an embodiment of the thermal recording device according to the present invention applied to a facsimile machine, in which FIG. 1 is a circuit diagram of the main part thereof, and FIG. 2 is an example of its printing operation. FIG. 3 is a flowchart showing a program for thermal recording control. 1...Thermal recording control device (constituting end element driving means together with data gate 8, latch 9, and shift register 10), 2...Black detector (dividing means), 3...・・・・・・
Counter group, 4...Timer, 5...Controller, 6...Thermal head, 7...Heating element,

Claims (3)

[Claims] (1) In a thermal recording device that prints by sending out heat pulses based on print data to heating elements arranged in a row,
dividing means for dividing the print data into a plurality of blocks;
A driving means that sequentially sends heat pulses to the heat generating elements corresponding to the divided data block by block, and a heat pulse when printing subsequent blocks to the heat generating elements corresponding to the print data based on the print data located at the end of the block. 1. A thermal recording device characterized by comprising: an end element driving means for sending out. (2) The thermal recording device according to claim 1, wherein the dividing means determines the number of print data to be divided based on the power supply capacity of the thermal recording device and the print data. (3) The thermal recording apparatus according to claim 1, wherein the end element driving means sends out heat pulses based only on one piece of print data located at the end of the next block.