JPH01206070A - Method and device for electrically conducting thermal head in thermal printer - Google Patents

Abstract

PURPOSE:To prevent a blur in printing, by a method wherein a printing is carried out while a non-printing area of a predetermined address to be selected is preheated. CONSTITUTION:If image data for 8 dots is supplied to a 3-line buffer 13 from an external equipment, according to the data the 3-line buffer 13 stores the data for one line. Simultaneously, signals for three lines are successively fed to a surrounding dot buffer 15 correspondingly to shift signals for every dot. To detect the state of the surrounding dots corresponding to a window frame M from the data for three lines, the surrounding dot buffer 15 processes the data for 5 dots as an address signal. On the other hand, according to this signal an intermediate code table 16 determines an intermediate code of an address corresponding to a window frame pattern M0 which is previously inputted from a CPU 2. This intermediate code represents a post-correction heating time for preventing a blur in printing. In this manner, an intermediate code is calculated for every area for one dot, whereby the number of application per dot, i.e. the number (time) of conduction, is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and device for energizing a thermal head in a thermal transfer or thermal printer.

[Conventional Technique W4] As shown in Fig. 3, the energizing device for the thermal head in a conventional thermal printer is connected to an external device such as a personal computer that generates image data for creating a line drawing pattern to be printed, and this image Centro interface circuit (hereinafter referred to as 17F circuit) that receives data; CPU 2 that controls the entire printer; Random access memory (hereinafter referred to as RAM) 3 for Niprogram work;
Read-only memory (hereinafter referred to as ROM) 4 for storing the nib program; operating circuit 5; shift register 6a, latch circuit 6b, thermal head drive circuit 7a
and a thermal head S equipped with a heating element 7b; a driver circuit 8; and a paper feed valsmo.

- Tau; transfer ribbon winding pulse motor 10; thermal head press-contact solenoid 11;

In the above configuration, image data input from an external device via the I/F circuit 1 is sent one line at a time to the shift register 6a, which passes through the CPU 2, and is stored therein.

Next, a latch circuit signal is applied to the latch circuit 6b to transfer the image data in the shift register 6a to the latch circuit 6b. Thereafter, a common signal is outputted from one heating element 7b for a time corresponding to the temperature state of the thermal node S to operate the drive circuit 7a, and a current is passed through the required heating element 7b to print. In this case, printing for one line is performed by sequentially outputting common signals from the CPU 2. On the other hand, various drive commands are given from the CPU 2 to the driver circuit 8 via the operation circuit 5, and the paper is fed by the motor 9. 10 winds up the transfer ribbon, and excitation of the solenoid 11 causes the image data to be thermally or thermally transferred printed according to the method of the thermal printer.

[Problems to be Solved by the Invention] By the way, in the above-mentioned conventional printing device, among the heating elements constituting the thermal head, current is applied to each heating element that prints for a certain period of time, and current is applied to each heating element that does not print. Printing control was in place to prevent printing.

For this reason, when printing a line drawing pattern in which a printed area appears after a long period of no printing during printing, for example, a lattice pattern consisting of vertical lines and horizontal lines as shown in Figure 4, it is difficult to print until the printed area is reached. In some cases, the heating element cools down, resulting in interrupted printing and blurred areas.

Generally, the heating time for printing paper by 7 heating elements is 5th.
As shown in the figure, when the time is less than 9 hours T2, there is a non-printing area of 1 hour from T2 to T, when it is an intermediate area of 5 hours T where printing or no printing is determined depending on the environmental temperature, and when it exceeds T2, there is printing. (Hereafter, as an example, T
t to 2. The explanation will be made assuming that T is 3 and the maximum heating time is 6, and that the preheating time T is 1 to prevent blurring even though it is a non-print area. ) This kind of blurring occurs in various cases.

The present invention aims to prevent blurring in the following two cases.

■When printing a grid pattern consisting of vertical and horizontal lines,
In the case of blurring that occurs on horizontal lines, if you preheat the adjacent area to prevent blurring in the horizontal line area, the blurring that occurs in the vertical line area. The first order is as follows.

In other words, in the case of printing vertical lines, when printing each line, the amount of heat added to print the previous line is stored and added to the printing of the next line, so the amount of heat required for printing is 1 Normally, no blurring occurs, but in the case of horizontal lines, printing is performed in an area where there is a long non-printing area, 1 The heating element also gets cold, and there is no heat accumulation as described above. The amount of heat required for printing is insufficient, and even if current is applied to the heating element for the same amount of time as other printing parts, blurring occurs (see Figure 4).

In addition, in order to prevent blurring of horizontal lines in consideration of such a situation, a correction as shown in the first embodiment of the present invention described later, that is, a correction that preheats the non-print area is performed. If you do this, this preheating method does not preheat the area immediately next to the vertical line to be printed, so the vertical line will appear thinner as the horizontal line becomes clearer, and it will appear fainter when compared to the horizontal line. (See Figure 4).

An object of the present invention is to provide a method and device for energizing a thermal head in a thermal printer to prevent blurred printing that occurs in these cases.

[Means for Solving the Problems] The energization method of the present invention includes the following steps to solve the above problems.

■The line drawing pattern to be printed by a thermal printer is passed through a window frame of a predetermined shape such as an inverted T-shape before printing.

(2) Detect and store the addresses of the printed area and non-printed area by passing through the window frame.

■Based on the memory of the addresses of the printing section and non-printing section and the instructions from the CPU, the energy applied to each heating element of the thermal printer and its thermal head is changed between the printing section and the non-printing section. Preheating is applied to a predetermined non-print area.

(2) By providing the above-mentioned preheating step, the difference in temperature of the heating element between the continuous printing section and the discontinuous printing section is reduced during printing.

Also, as an energizing device used to carry out this energizing method.

・CPU that issues printer control commands.

A 3-line buffer that transfers 3 lines of data corresponding to an area of 5 dots on the window frame that is the detection object; ・Data that indicates the state of surrounding dots by extracting input data from these 3-line buffers. a surrounding dot buffer that converts the address signal into an intermediate table address signal; -receives the address signal from this surrounding dot buffer;
This signal is compared with the area to be preheated given in advance from CI) U, and is compared with the address, and then converted into separate intermediate codes indicating the printing area, preheating area, and non-printing area without preheating. An intermediate code table; and is configured to control each heating element so as to preheat the predetermined non-print area to be preheated.

[Embodiments] The first and second embodiments of the present invention shown in FIGS. 1 and 2 will be described below.

In FIG. 1, components that are equivalent to those in FIG. 3 are designated by the same reference numerals.

First, the configuration of an apparatus of the present invention that can be used in common to implement the first and second embodiments of the present invention will be explained with reference to FIG.

In Figure 1, 13 is a 3-line buffer.

This receives one dot line data sent from the I/F circuit 1 and transfers it sequentially, but in order to see the surroundings of the printed dot, it transfers data for the current line (n), the previous line (n-1), and the line before the previous one (n). 3 lines of n-2) are stored.

A line counter 14 is used while ringing the 3-line buffer 13, and is also used as an address generation circuit for one line. the current.

The driver circuit 8 controls the line counter 14 and stores data for one line.

Reference numeral 15 denotes a peripheral dot buffer (including a latch circuit), as shown in Fig. 2 (a), for 3 dots of print line (n), 1 dot of the previous line (n-1), and Each data of five dots corresponding to one dot of the previous line (row 2) is extracted from the three-line buffer 13, and the data indicating the state of one surrounding dot is converted into an address signal of the intermediate table.

Reference numeral 16 denotes an intermediate code table, which receives an address signal and contains a pattern to be detected using a window frame M given in advance by the CPU 2, that is, 1. In the case of the first embodiment of the present invention, the intermediate code table is ) and the address where the pattern M0 shown in ) is printed.

In the case of the second embodiment, the addresses where the patterns M and 1M2 shown in FIGS. 2(d) and 2(po) are printed, and
The intermediate code in the intermediate code table given in advance from the PU is used to convert into an intermediate code. Each time, by giving the address of the input data to the intermediate code table, the output data is treated as an intermediate code, and an intermediate code indicating the number of times each frame point is applied (how to determine this code value will be explained later) ).

Reference numeral 17 denotes a two-line intermediate code buffer, which stores two lines, the previous one and the entire print, and repeats this until one line of printing is completed, and always outputs the previous intermediate code signal B.

18 is an energization frequency counter that calculates the number of energizations per common, and the number corresponds to the time of 1 common.

For example, seven numerical values from 0 to 6 (represented by code signal A) are sequentially output to the comparator 19.

A comparator 19 compares the A and B signals for one dot sent in units of one common, and outputs a print signal 1 if A<H, and a non-print signal 0 if A2B.

20 counts the number of commons per line.

This is a common counter indicating the end of printing for 1947 minutes. Therefore, the signal A from the 1 energization counter 18 is designed to output a code signal A for the number of energizations that sequentially generates a predetermined number of numerical values from 0 to n determined by the processing time of one dot's worth of data. In addition, the shape of the window frame M will be explained using an inverted T-shaped example, but it is not limited to this. For example, a rectangular window frame consisting of data of 9 dots for 3 lines It's okay.

(First Embodiment) First, an energization method according to a first embodiment of the present invention will be described with reference to FIGS. 2(B) and 2(C).

FIGS. 2(B) and 2(C) respectively show an inverted T as a detection body for detecting a non-printed area applied to the first embodiment of the present invention.
2 is a plan view showing a character-shaped window frame M and a relationship between the window frame and printing paper, in which the horizontal axis represents the moving direction of the window frame M, and the vertical axis represents the direction of a downwardly printed line. In addition, in FIGS. 2(b) and 2(c), for convenience of explanation, vertical lines forming a grid are shown.

The printed part of the horizontal line is 1. O the blank area where nothing is printed.
shall be displayed as The above-mentioned inverted T-shaped window frame M is moved 3 lines by 1 dot line to create this pattern M0.
It is determined whether or not the address matches the address, and if they match, this is detected as a non-print area to be preheated.

For example, Pl shown in the outline in FIG. 2(C).

P2. The area matching the pattern M0 shown in P is detected as a non-print area that should be preheated on the window frame M, but P
In the case of one dot to the left of l, when compared with window frame M in (b), the left end of the horizontal frame is 1, so the vertical frame is detected as a non-printing area, but an area to which no preheating is applied. (Note that this area becomes a preheating area in the second embodiment).

Next, the energization operation for preheating to prevent horizontal lines from fading in the first embodiment of the present invention will be supplementarily explained in relation to the apparatus shown in FIG.

For example, image data for 8 dots is sent from an external device to 3
When supplied to the line buffer 13, the 3-line buffer 13 stores 231942 pieces of data based on this. At the same time, each signal for three lines is sequentially transferred to the surrounding dot buffer 15 in correspondence with the shift signal one dot at a time. The surrounding dot buffer 15 has 3
In order to detect the state of the surrounding dots corresponding to the window frame M from among the data for the line, the data for 5 dots is treated as an address signal, and on the other hand, the intermediate code table 16 The intermediate code of the address corresponding to frame pattern M0 is determined by the first-order conditional expression.

That is, the intermediate cord construction corresponds to the number of heating (application) times K,
Total heat decay (application) time per one heating (application)
Time]゛. When , it is given by the 9th order equation.

T,=ni=ni,/T.

Therefore, for example, if NiA is 6. If To is 1,
Intermediate code T. becomes 6.

This intermediate code is the heating time after correction to prevent blurred printing, and for example, as shown in FIG. 5, the total heat disintegration time per common time for printing is 6. The preheating time is set to 1, which is a numerical value in the non-printing area, and 0 in the case of no printing without preheating. In this way, the intermediate code is calculated for each area of 1 dot, and 1
This is to correct the number of times of application of dots, and therefore the number of times of energization (time).

The intermediate code buffer 17 receives the intermediate code for the first one dot and one line, and then stores the intermediate code for the entire first dot line in the interval (so that this interval coincides with the time of one line). The previous intermediate code signal B is sent to the comparator 19.

Therefore, the comparator 19 receives a signal B for each dot, which is set corresponding to each address and is sent to distinguish between printing (6), no printing (0), and preheating (1) as shown in FIG. and the signals A of 0 to 6 sent sequentially from the 0 energization counter 18 for each common,
Generates an energization signal with correction.

For example, in the case of the print area, signal B is 6, so this 6 and the signals sent as signal A are 0, 1, 2, 3, 4,
In order to compare the seven signals of 5.6 and the comparator 19, ■ sequentially during the common section.

1. An energization signal indicating the number of energizations of 1, 1, 1, 1.0 is issued, and the heating element is heated for 6 times as the printing area.

Similarly, in the preheating region, 1 is applied as signal B to the 1-common section comparator 17, so it is compared with signal A, which is sequentially applied as 0 to 6. O, O.

The energization signals of o, o, o, o are sent to a section of one common, and the heating element is heated as preheating with 9 energizations once.

In addition, in a non-printing area that does not involve preheating, 0 is given to the comparator 19 as signal B, so the 1 energization signal becomes 0 and 1
Do not energize the heating element.

In this way, the next 2 commons, 3 commons, 4 commons and 1
When printing of all lines is completed, printing of the first dot line begins.

Note that the common counter 20 is used to specify the common to which the thermal head is energized.

Furthermore, the correction area targeted for this heating time is an area that matches the pattern M0 already specified in the intermediate code table 16 (for example, the area P, , P
,,P, ---) Therefore, the heating element heats the adjacent area that is a continuous non-printing area excluding the non-printing area immediately next to the vertical line printing area and the vertical line printing area. By adjusting the time 1m to reduce the temperature difference between the two, blurred printing of horizontal lines can be prevented.

Do the same for each of the next dot lines.

Note that the thermistor signal given to the A/D converter 12 is determined by a separately placed thermistor that detects the environmental temperature, and depending on the change, the preheating type determines the appropriate value (for example, if the current is turned on for preheating depending on the environmental temperature) (to avoid printing on the paper).

In addition, the driver circuit 8 drives each motor 9, 10 and excite the solenoid 11 after comparing the data sent from the line counter 14 with the command from the CPU 2 and outputs the output, which is exactly the same as the conventional one. It is intended to be controlled.

(Second Embodiment) (D), (E), and (F) in FIG. 2 each represent an inverted T-shaped detection object for detecting a non-printed area applied to the second embodiment of the present invention. FIG. 3 is a plan view of a window frame M and a plan view showing the relationship between the window frame and printing paper.

In the second embodiment, the address areas where patterns M, . . . M2 are printed are detected, and correction for blurred vertical lines is performed.

Therefore, in this case, address areas corresponding to patterns M, M2 shown in FIG.
Intermediate code table 1
6, and the area where the left or right end of the horizontal frame is 1, as shown by the large frame in (v).

In other words, in the first embodiment, the non-print area removed, that is, 1
M! It is detected as a non-print area immediately adjacent to the printed line area. Therefore, as in the case of the first embodiment, the 3-line buffer 13. The extracted signal B applied via the surrounding dot buffer 15 and the intermediate code buffer 17 is sent to the comparator 19.

Compare with signal A from energization counter 18.

For example, by generating a correction signal for the number of times of energization of 1 to be applied as a preheating area to each dot corresponding to a non-printing area located immediately next to the vertical lines indicated by Ql and Q2 in FIG. The heating time of the heating element of the thermal head is controlled, and the heating time of the heating element is adjusted for the printed part of the vertical line and the non-printed part immediately next to it (the non-printed part removed in the first embodiment). 0 By reducing the temperature difference between the two, blurred printing of vertical lines is prevented.

Note that the other functions are the same as those of the first embodiment, so a description thereof will be omitted.

[Effects of the Invention] As described above, the present invention analyzes whether the information data to be printed is a printed area or a non-printed area before printing, so that the information data is located immediately next to a vertical line in the area to be printed. an adjacent area that is a continuous non-print area (first embodiment), excluding the non-print area
Alternatively, by selecting an area containing only the non-print area immediately adjacent to the vertical line removed in the above case (second embodiment), the non-print area at the predetermined address selected in this way is It is designed to print while preheating. For this reason, the area that becomes the printing area (for example, in the grid pattern shown in the example, the horizontal line, and when printing the horizontal line) It has an excellent feature of being able to print clearly (vertical lines, etc.) without blurring when preheating is controlled.

[Brief explanation of the drawing]

Fig. 1 is a connection diagram showing an example of an energizing device to which the method of the present invention is applied, and Fig. 2 is a plan view, of which (a) and (b)
(D) and (E) are respectively plan views of a window frame as a detection object, and (C) and (F) are plan views showing the relationship between the window frame and printing paper. FIG. 3 is a connection diagram showing the configuration of the conventional device, FIG. 4 is a plan view showing blurred printing caused by the conventional device, and FIG. 5 is a diagram showing the relationship between printing condition and heating time. Centro interface circuit 2: CPU 3: RAM 4: ritOM 5: Operation unit circuit S: Thermal head M: Window frame 13: 3 line buffer 14: Surrounding dot buffer 16: Intermediate code table 18: Energization number counter 19: Comparator Applicant Shinko Electric Co., Ltd. Agent Patent attorney Haruya Saito and two others Figure 2 □ Direction of movement of window frame (2) (E) □ ! Frame movement direction

Claims (1)

[Claims] 1. Before printing, the line drawing pattern to be printed by a thermal printer is passed through a frame of a predetermined shape to detect and store the addresses of the printed area and the non-printed area. Based on this memory and commands from the CPU, the energy applied to each heating element of the thermal head of the thermal printer is changed between the printed area and the non-printed area, and for a predetermined non-printed area of the above-mentioned non-printed area, A method for energizing a thermal head in a thermal printer, characterized in that the temperature difference between heating elements in a continuous printing section and a discontinuous printing section is reduced during printing by applying preheating. 2. Using a frame with a predetermined shape, detect each address in a predetermined non-print area where all vertical and horizontal lines are 0 when viewed from this frame. Claim 1: The heating time for horizontal line printing is corrected by giving an address of a predetermined area as a command.
How to energize the thermal head in the described thermal printer. 3. Using a frame with a predetermined shape, detect each address in a predetermined non-printing area where the right or left end of the horizontal frame is 0 when viewed from the frame, and on the other hand, receive a verification command from the CPU. 2. The method of energizing a thermal head in a thermal printer according to claim 1, wherein the heating time for vertical line printing is corrected by giving an address of a predetermined area. 4. CPU that issues control commands for the printer; Centro interface circuit (hereinafter referred to as I/F circuit) that accepts image data sent from external equipment such as a personal computer; Random access memory for program work; Program Read-only memory for storage; operation unit circuit; shift register, latch circuit, thermal head drive circuit, and thermal head equipped with a heating element; 3 lines of data corresponding to 5 dots of the window frame A 3-line buffer that performs the transfer; A surrounding dot buffer that uses the input data from this 3-line buffer to extract a predetermined dot area of the window frame that indicates the state of each surrounding dot and uses it as an address signal; After receiving an address signal and comparing this signal with the address given in advance from the CPU indicating whether it is a printing area, a preheating area, or a non-printing area without preheating, a separate intermediate code is determined for each area. Intermediate code table to be converted into; Intermediate code buffer that stores two lines of data for the previous line and current line of the intermediate code from this intermediate code table, and always outputs the previous code signal B; 1 dot worth an energization counter that outputs a code signal A indicating the number of energizations that sequentially generates a predetermined number of numerical values from 0 to n determined by the data processing time;
A comparator that compares the A and B signals for one dot sent from the intermediate code buffer and the energization counter, determines the presence or absence of energization, and outputs an energization signal; For each address in the character area,
Based on the energization signal of the above comparator, the applied energy is changed for each heating element of the thermal head of the thermal printer, and heating is performed to reduce the temperature difference between each heating element between the continuous printing section and the discontinuous printing section. A thermal head energizing device in a thermal printer configured to perform time correction control. 5. When the heating time for the thermal head is K_r and the heating time per time is T_0, the intermediate code is K_
5. The thermal head energizing device in a thermal printer according to claim 4, wherein r/T_0 is defined. 6. The energizing device for a thermal head in a thermal printer according to claim 4, further comprising a thermistor, the heating time being corrected for the environmental temperature by detecting the environmental temperature.