JPH0315551B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal printer, and more particularly to a thermal printer in which end points and isolated point portions can be printed with good print quality to improve print quality.

[Technology overview]

For example, thermal printers are used as output devices for data processing devices such as word processors. There are two types of thermal printers: a color-forming type that uses paper coated with a heat-sensitive coloring agent that colors when heated, and a thermal type that uses paper coated with a heat-sensitive coloring agent that colors when heated, and a thermal type that uses paper coated with a heat-sensitive coloring agent that colors when heated, and a thermal type that uses paper coated with a heat-sensitive coloring agent that colors when heated, and a thermal type that uses paper coated with a heat-sensitive coloring agent that develops color when heated, and a thermal type that uses paper coated with a heat-sensitive coloring agent that develops color when heated, and a thermal type that uses paper coated with a heat-sensitive coloring agent that develops color when heated. There are transfer types that use a thermal ink ribbon coated with ink. Among such thermal printers, in the case of a serial type having a serial head, the thermal printer is operated by selectively energizing the necessary heating elements among the plurality of heating elements arranged in the vertical direction provided in the thermal head. Perform arbitrary printing while moving the head.
At this time, the printing density is determined by the temperature of the heat generating part of the thermal head.

FIG. 1a shows a part of a transfer type thermal printer.

A normal paper 2 is placed on a platen 1, a thermal ink ribbon 3 is placed on it, and a thermal head 4 prints on it. The thermal head 4 is provided with an elongated heat generating section 5, as shown in FIG. 1b. This heating section 5 includes a plurality of heating elements, for example, one heating element in the case of 16-dot printing.
Six heating elements are provided, and characters, symbols, figures, etc. can be printed by selectively heating them.

[Conventional technology and problems]

By the way, when using such a serial type thermal printer, as shown in Figure 1e, when printing vertical ruled lines, the connecting part L is not connected and is printed in a disconnected state, or the vertical ruled line is printed in a disconnected state. As shown, there is a problem that the print quality is poor in some parts, such as the isolated point P being printed thinly. The reason for this is
For example, when printing a vertical line as shown in Figure 1c, both ends are rounded, as shown by E in the enlarged view of Figure 1d, and the corners should originally be printed in a rectangular shape as shown in the dotted line. This results in a disconnection state. It was found that the reason why this phenomenon occurs is that even if each heating element is energized at the same rate, a temperature difference occurs due to the influence of adjacent heating elements, and the temperature at the end point decreases. . This is the same reason for the deterioration of print quality at the isolated point P shown in FIG. 1f.

That is, in the conventional printing control of this type of thermal printer, as shown in Fig. 2, when printing print data, the energization time control section uniformly controls the energization time to the heating element of the thermal head for each driver. This is due to the fact that it was under control.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal printer that improves the above-mentioned problem that the printing quality at end points and isolated points may deteriorate in this type of thermal printer.

[Structure of the invention]

In order to achieve this object, the thermal printer of the present invention includes a thermal head having a plurality of heating elements arranged adjacent to each other, a means for moving the thermal head relative to a printing medium, and a printing device. an end point detection unit that detects an end point or isolated point of a pattern; a means for detecting the presence or absence of a print pattern near the end point or isolated point from a print pattern printed before the end point or isolated point;
The present invention is characterized by comprising means for controlling the amount of heat generated by the heating element corresponding to the end point or isolated point depending on the presence or absence of a printed pattern in the vicinity of the end point or isolated point.

[Embodiments of the invention]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the present invention in detail based on one embodiment, an outline thereof will be explained. In the present invention, an end point (isolated point) in a printing pattern is detected, and when the peripheral part of this end point has not been printed by the previous printing, the energization time can be lengthened or a higher temperature can be generated. Control as follows. This makes it possible to prevent a drop in temperature at the end points (isolated points), thereby preventing the deterioration of print quality as described above.

An embodiment of the present invention will be described based on FIGS. 3 to 27.

The external appearance of the thermal printer of the present invention is shown in FIG. In FIG. 3, paper 2 is attached to upper cover 1.
The paper is inserted through the paper insertion slot 0, and the printed material is received from the paper holder 11. Figure 4 explains the inside of a thermal printer, in which a thermal ink ribbon 12 is used and space is
A motor 13 controls the movement of a carrier 15 having a thermal head 14. Thermal printers have internal line feed motors (LE) for feeding the paper, and an approach motor that controls the proximity of the thermal ink ribbon to the paper so that it does not stick to the paper as it is fed.
Mechanisms (not shown) such as an escape motor (AE) are installed. Note that FIGS. 3 and 4 show examples of transfer type thermal printers.

Next, an outline of the control according to the present invention will be explained.

For example, as shown in Fig. 5, when printing in a straight line using a printing pattern showing dots 4 to 16 as shown by the diagonal lines in register _R1 , the end point detection unit ED performs the operation described in detail later. Extract the upper and lower end points E ₁ and E ₂ of the pattern and set them in register R ₂ . And this end point E ₁ , E ₂
The end point energization determination unit TD shown in FIG. 7 determines whether the energization time for the terminal is kept as usual or longer than usual.

As shown in Fig. 6, this energization time judgment is based on the print data buffer when the end point to be judged is _E1 .
The previous print data _d2 and the print data _d1 from the time before the previous time stored in the BU are read out, and it is checked whether or not printing was performed in an area of two dots each above and below the end point _E1 . That is, a total of 10 dots .about. in the check area CH in FIG. 6 are checked. If one dot is not printed within this check area CH, a determination is made to increase the energization time at the end point _E1 . However, this check area CH
If even 1 bit of the bit is printed, the end point
The energization time of _E1 is not increased, and heating is performed at the normal energization time.

Therefore, as shown in FIG. 7, when determining the energization of the end points E ₁ and E ₂ in the register R _1-3 , the print data from the previous printing and the previous printing as shown in the registers R _1-1 and R _1-2 are used. Check the data. end point
For E ₁ , there is no print data in its check area CH ₁ , but for end point E ₂ , there is print data in its check _area CH ₂ . The energization determination unit TD makes a determination and outputs the determination result to the register _R2-1 . This results in endpoint E ₁
Control is performed to lengthen the energization time.

FIG. 8 is a block diagram of a thermal printer according to the present invention. In FIG. 8, 20 is an MPU (microprocessor), which is a general control unit for this thermal printer, 21 is a ROM, which stores programs necessary to operate the MPU 20, and 22 is a RAM. 23 is an input/output port that is used to hold input data and as a data processing register for the operation of the MPU 20, and is used to connect this thermal printer with an external device. 24 is an output port into which print data to be printed is input and a report signal reporting the print result is output, and various devices used in a thermal printer, such as a space motor 13, a thermal head 14, Approach escape motor 2
7. Outputs control signals, etc. to buffers 26-1 to 26-4 that control line feed motor 28, etc., and 25 is an input port from various sensors, response switches, etc. built into the thermal printer. The signal is input,
For example, a micro switch 30 for approach detection that detects the state in which the thermal head 14 is in relation to the paper, that is, how far down or up the thermal head 14 is, and the carrier 15 are located at the left end. A left end sensor 31 detects whether the paper 2 is present, a paper set sensor 32 detects the presence or absence of the paper 2, and a silver paper or the like provided at the final end of the ribbon detects that the thermal ink ribbon is in the ribbon end state. Output signals from the ribbon end sensor 33 and the like are input. Of these, the leftmost sensor 3
1. Since the paper set sensor 32 and the ribbon end sensor 33 are composed of photo sensors, each amplifier 2 of the photo amplifier 29
The amplified detection signals are input at 9-1 to 29-3.

Next, the operation shown in FIG. 8 will be explained.

When print data is transmitted from the host device to the input/output port 23, the MPU 20
The data is stored in the RAM 22, and printing is performed by supplying print data line by line to the thermal head 14 according to control instructions from the ROM 21. At this time, the left end sensor 31 detects whether the thermal head 14 was initially located at the left end, and thereafter the space
A motor 13 sequentially drives this thermal head 14 in the printing direction. When one line of printing is finished, the approach/escape motor 27 moves the thermal head 14 away from the paper to create a space.
The motor 13 is connected to the thermal head 14 and the thermal head 14.
Shift the ink ribbon together to the left end and print the next line. Of course, at this time, the paper is fed a new line by the line feed motor 28. When the paper runs out, this is detected by the paper set sensor 32, and if the thermal ink ribbon needs to be replaced, it is detected by the ribbon end sensor 3.
3 will detect and report to the MPU 20 respectively.

By the way, the MPU20 has the following information as shown in Figure 9.
An end point detection section 40, an end point energization determination section 41, an energization time control section 42, a register section 43, and the like are provided. The configurations of the end point detection section 40 and the end point energization determination section 41 will be described in detail later.

For example, the end point detection unit 40 performs end point detection on input data as shown in _FIG .
When E ₂ is detected and the end point energization determination unit 41 determines that the energization time of the end point E ₁ should be lengthened in the state shown in FIG.
Printing control is not performed for dots ₁ to 3 of register R1 in the figure, and for dots 5 to 16, energization control to the heating element of the thermal head is performed at the conventional energization time _T0 , but the fourth dot Since the heating element is energized for a time extended by ΔT before and after T ₀ , a temperature drop with respect to this end point E ₁ is prevented, and printing is performed with the correct density and shape. Note that FIG. 10 shows a conventional energized state for comparison with the present invention. In the conventional case, the heating element is controlled with a uniform energization time of T ₀ for the character pattern part regardless of whether it is an end point or not, so for the character pattern of register R ₁ , As shown in Figure 10,
This shows that dots 1 to 3 are not energized, and dots 4 to 16 are energized for an energizing time _T0.As shown in FIG. 12, the thermal head 14 has the following: 16 heating elements h ₁ for each dot
h ₁₆ is provided, and drivers (transistors having a Darlington circuit configuration) D ₁ to _{D 16} are connected to one end of each heating element. Therefore, if you selectively input a pulse signal to this driver,
Each heating element generates heat for a time corresponding to this pulse width.

In addition, the space motor 13 is composed of a four-phase pulse motor of A phase to D phase, and selectively turns on drivers (transistors with Darlington circuit configuration) D _a to D _d connected to each phase coil A to D. - By performing OFF control, current flows selectively to each phase coil A to D, and the control is performed in a 1/2 phase system, as shown in FIG. 14, for example.

When the space motor 13 is started, the A phase is excited for a long time, then the AB phase, B phase, BC phase...
The excitation time is sequentially shortened, and when this acceleration time has elapsed, constant speed operation is performed at the printing speed. Even during this constant speed operation, the A phase, AB phase, B phase, etc. are controlled in a 1/2 phase system. Then, as shown in FIG. 15, the thermal head is energized based on the phase switching point of the space motor. The heating element of the thermal head is energized at t ₁ from this phase switching point.
However, when end point energization control is performed, energization is started after a delay of t ₂ (t ₁ >t ₂ ) from this phase switching point.

Next, the characteristic end point detection control and end point energization determination control of the present invention will be explained.

The end point detection control and the end point energization determination control are performed in the first
As shown in FIG.
BU3, 1st processing register r ₁ to 4th processing register
The thermal head is energized by setting the print data obtained as a result of processing such as _r4 to the output port p.

A First, two embodiments of end point detection processing will be described.

(1) End point detection processing (first embodiment) In this first embodiment, as shown in FIG.
3, and the first processing register r ₁ to third processing register r ₃
use. This first processing register _r1 is configured to be output by the carry.

As shown in the flowchart of Figure 18, the third processing register _r3 is cleared, and then the third buffer BU
The current print data set to 3 is transferred to the first processing register _r1 . At this time, if the print data set in the first processing register _r1 are not all "〓", "0001" is written in hexadecimal in the second processing register _r2 . As a result, "1" is set in the least significant bit 1 of the second processing register _r2 , resulting in the states shown in FIGS. 17 and 19a.

In this state, the first processing register _r1 is rotated to the right. At this time, if the carry is not output from the first processing register _r1 , the second processing register _r2 is rotated to the left. As a result, the first processing register r ₁ and the second processing register r ₂ become as shown in FIG. 19b.

This rotates the first processing register _r1 to the right. At this time as well, since the carry does not output any output, the second processing register _r2 is rotated to the left, resulting in the state shown in FIG. 19c. Then, the first processing register _r1 is rotated to the right, but since no carry is output, the second processing register _r2 is also rotated to the left. In this way, the state shown in FIG. 19d is reached. Then, if the first processing register _r1 is output to the right, the first processing register
Carry CR=" ₁ " is output from r1, so at this point the data in the second processing register _r2 is set in the third processing register _r3 . At this time, as shown in Figure 19d, since "1" exists in bit 4 of the second processing register _r2 , this indicates the upper end point _E1 set in the third buffer BU3. .

Next, the data in the third buffer BU3 is set again in the first processing register _r1 , and then in the second processing register _r2 .
"8000" in hexadecimal notation, or "100..." in binary notation
00”. This allows the first processing register
The data of r ₁ and second processing register r ₂ are set to the state shown in FIG. 20a. Then, the first processing register _r1 is now rotated to the left. At this time, carry CR="1" is output from the first processing register _r1 as shown in FIG. 20b, so at this time the second
Since the data set in the processing register _r2 indicates the lower end point, the lower end point of the current print data set in the _third buffer BU3 from the state of the second processing register r2 must be the most significant bit 16. I understand.

(2) End point detection processing (second embodiment) The second embodiment of end point detection is shown in FIGS. 21 and 22.
This will be explained using figures. In this second embodiment, the print data held in the third buffer BU3 is set in the first processing register _r1 , and an initial value is set in the fourth processing register _r4 used as a counter. Each time _r1 is rotated, it is incremented by +1 or -1, and this continues until the carry outputs. This will be explained below with reference to the flowchart of FIG.

First, the second processing register _r2 to the fourth processing register
_r4 is cleared and the print data written in the third buffer BU3 is transferred to the first processing register _r1 . At this time, if the print data set in the first processing register _r1 is not all "0", "1" is added to the fourth processing register _r4 . This allows the fourth
The value 1 is written in the processing register _r4 . In this state, the first processing register _r1 is rotated to the right. At this time, if a carry is not output from the first processing register r ₁ , the fourth processing register r ₄ is further +1
do. Then, the first processing register _r1 is rotated to the right. This kind of thing is done in the first processing register.
Repeat from r ₁ until Carry CR="1" is output. When carry CR="1" is output, the numerical value written in the fourth processing register _r4 indicates the position of the upper end point of the print data set in the third buffer BU3. In the example of FIG. 21, when the first processing register _r1 is rotated to the right four times, carry CR="1" is output, so the value " ₄ " written in the fourth processing register r4 at this time is output. ”
indicates the upper end point of this print data. Therefore, by setting the bit corresponding to the count value of the fourth processing register _r4 to " ₁ " in the third processing register r3, the upper end point can be set in the third processing register _r3 .

Once the upper end point is set in this way, the lower end point is then set. For this reason, the third buffer
The print data set in BU3 is set again in the first processing register _r1 , and this time a numerical value 17 is initially set in the fourth processing register _r4 . This numerical value 17 indicates a value obtained by adding 1 to the number of bits of one column of print data. Next, the value set in this fourth processing register _r4 is decremented by 1, and then the first processing register _r1 is rotated to the left. At this time, carry
Since CR="1" is output, the number counted by the fourth processing register _r4 (in this case, 17-
1=16) is set to "1" in the second processing register _r2 . In other words, 16 of the second processing register r ₂
The th bit is set to ``1'' and indicates the location of the bottom endpoint.

B Two embodiments of end point energization determination control will be described.

(1) End point energization determination control (first embodiment) In this first embodiment, as shown in FIG.
The first buffer where the print data from the previous printing is entered
BU1 and 2nd BU where the previous print data was entered.
Buffer BU2 and first processing register _r1 to third processing register _r3 are used. In this case, the lower end point _E2 is set in the second processing register _r2 by the above A, and the upper end point _E1 is set in the third processing register _r3 .

As shown in the flowchart of FIG. 24a, the upper end point _E1 of the third processing register _r3 is transferred to the first processing register _r1 . And the first bath BU1
The logical product of the previous print data and the data in the first processing register _r1 is calculated for each bit, and the result of this operation is set in the first processing register _r1 . Then, it is determined whether this is all zero or not.
In this case, the print data from the previous printing is shown in Figure 7.
_R1-1 , and in the first processing register _r1 , only "1" indicating the upper end point _E1 is written in the position of bit 4, and other bits 1 to 3 and 5 to 16 are written.
is "0". Therefore, the logical product of each bit of the first processing register _r1 and the first buffer BU1 is "0". If “1” is output as a result of this logical product, then
"1" exists in the bit 4 part of the print data from the previous time, indicating that it was printed and heated, so in this case there is no need to lengthen the energization time of _E1 , and it is set in the third processing register _r3 . This will clear the upper end point _E1 .

Next, set the upper end point E ₁ of the third processing register r ₃ in the first processing register r ₁ again, and this time perform a logical product with the second buffer BU 2 corresponding to the bits and set the operation result in the first processing register r ₁ . do. If the result is "1", the third processing register _r3 will be cleared, but if the previous print data of the second buffer BU2 is shown in register _R1-2 in FIG. 0".

Next, it is checked whether print data exists in the area shown in FIG. Therefore, the upper end point E ₁ of the third processing register r ₃ is set to the first processing register
Set r to ₁ , then rotate it to the left by 1 bit. and the first processing register r ₁
and the first buffer BU1, and set this operation result to the first processing register _r1 . If this is "0", the upper end point _E1 of the third processing register _r3 is set to the first processing register r1 again. ₁ , rotate it 1 bit to the left, calculate the AND of the second buffer BU2, and apply this operation result to the first buffer.
Set processing register _r1 . If this is "0", then the area shown in FIG. 6 is checked.

Therefore, the upper end point _E1 of the third processing register _r3 is set to the first processing register _r1 , and it is rotated 2 bits to the left, and the upper end point E1 of the third processing register r3 is set to the first processing register r1.
and the result of this operation is set in the first processing register _r1 . If this is "0", the upper end point _E1 of the third processing register _r3 is set to the first processing register _r1 again, this is rotated 2 bits to the left, and this time it is ANDed with the second buffer BU2. The result of this calculation is set in the first processing register _r1 , and it is determined whether or not this is "0". If this is ``0'', the next check is performed in the areas ~ in Figure 6.

Similarly to ~ above, transfer the upper end point _E1 of the third processing register _r3 to the first processing register _r1 , rotate it to the right by 1 bit, and
A logical product is calculated between the buffer BU1 and the second buffer BU2. If at least one of these operation results is not "0", the upper end point _E1 of the third processing register _r3 is cleared, but both are "0".
If so, transfer the upper end point _E1 of the third processing register _r3 to the first processing register _r1 , rotate it to the right by 2 bits, and find the AND with the first buffer BU1 and the second buffer BU2. , performs similar processing. In this way, if all the calculations regarding the upper end point E ₁ are "0", the upper end end point E ₁ written in the third processing register r ₃ is left as is, and the end point energization judgment control is performed for the lower end end point E ₂ . to move to.

This time, as shown in the flowchart of FIG. 24b, the data of the lower end point _E2 written in the second processing register _r2 is set in the first processing register _r1 , and is set in the first buffer BU1. Calculate the logical product with the print data from the time before last. If the print data from the previous printing is set in register _R1-1 in Fig. 7, this calculation result contains "1", so the second processing register _r2 is cleared and the lower end point _{E2 is} set. data is erased and the energization time is not extended when printing the lower end point _E2 .

However, if this logical product is "0", the data at the lower end point _E2 of the second processing register _r2 is set again in the first processing register _r1 , and then in the second buffer BU2. Calculate the logical product with the previous print data. If this is also "0", the _second
Set the data at the lower end point _E2 of the processing register _r2 to the first processing register _r1 , shift it 1 or 2 bits to the left or right, and perform a logical product with the first buffer BBU1 or the second buffer BU2. seek. If the result of these checks is "1" even once, the second processing register _r2 is cleared. However, if both are "0", it is determined that the energization time should be extended for this lower end point _E2 .

In this way, the logical sum of the data of the lower end point _E2 set in the second processing register _r2 and the data of the upper end point _E1 set in the third processing register _r3 is calculated, and this is added to the first processing register. r Set to ₁ . Then, only the end point written in this first processing register _r1 is determined and controlled as the one whose energization time should be extended.

By the way, the procedure shown in FIGS. 24a and 24b is based on the basic concept and requires a long processing time because it is a simple process that is repeated. Therefore, by adding one processing register, we can check the check area in Figure 6.
Processing time can be significantly reduced by checking 10 dots at once. Next, add this to the 25th
26a and 26b, a second embodiment of end point energization determination control will be described. In this second embodiment, the second processing register _r2 or the third processing register
Create window data from the end point data of _r3 in the fourth processing register _r4 , and
The previous time set in the second buffer BU2,
The previous print data is summarized as a logical sum and transferred to the first processing register _r1 , and the first processing register _r1 and the fourth processing register _r4 are checked, and the judgment is made at the top and bottom edges. This will be done separately.

(2) End point energization determination control (second embodiment) First, the data of the upper end point _E1 of the third processing register _r3 is set in the first processing register _r1 and the fourth processing register _r4 . and the first processing register r ₁
Rotate 1 bit to the right. In this state, the logical OR of the data in the first processing register _r1 and the fourth processing register _r4 is calculated and this is added to the fourth processing register r4.
Fill in processing register _r4 .

After the above operation is completed, the first processing register _r1 is further rotated to the right by one bit. In this state, the first
The logical OR of the data of processing register _r1 and fourth processing register _r4 is calculated and this is sent to the fourth processing register.
Fill in r ₄ .

Next, the data at the upper end point _E1 of the third processing register _r3 is set in the first processing register _r1 again, and this time it is rotated 1 bit to the left.
In this state, the logical sum of the first processing register _r1 and the fourth processing register _r4 is calculated and the result of this operation is written in the fourth processing register _r4 .

After the above operation is completed, the first processing register
Rotate r ₁ further to the left by 1 bit. The logical sum of the first processing register _r1 and the fourth processing register _r4 is calculated and written in the fourth processing register _r4 . In this way, "1" is written in the area of two dots on the left and right sides of the fourth processing register _r4 , including the upper end point _E1 .

Then, the print data from the previous printing set in the first buffer BU1 is transferred to the first processing register _r1 , and the logical sum of this data and the data in the second buffer BU2 is determined in correspondence with bits, and the result of the operation is transferred to the first processing register r1.
Fill in processing register _r1 .

The logical product of this first processing register _r1 and the data of the fourth processing register _r4 in which the aforesaid operation result has been written is determined in correspondence with the bits, and the result of the operation is set in the first processing register _r1 . At this time, if the print data from the previous or last time exists in the 10-bit check area indicated by CH in FIG _. However, if there is no print data, the result of this _calculation will be all "0", and it is determined that the upper end point _E1 should have its energization time extended. Since the determination for the upper end point _E1 is thus completed, the determination for the lower end point _E2 shown in FIG. 26b is now performed.

The determination for the lower end point E ₂ is performed by inputting the data of the second processing register r ₂ in which the lower end end point E ₂ is written into the first processing register r ₁ and the fourth processing register r ₄
from then on, the upper end point E ₁
The details are omitted because the procedure is the same as the determination for . As a result, if the lower end point _E2 does not require an extension of the energization time, the second processing register _r2 will be cleared.

In this way the upper endpoint E ₁ and the lower endpoint
When the determination regarding _E2 is completed, the logical sum of each data in the second processing register _r2 and the third processing register _r3 is calculated, and the result of the calculation is set in the first processing register _r1 . In this way, the end point energization time is extended only for the data finally set in the first processing register _r1 .

For example, "H" can be printed by the thermal printer of the present invention.
When printing, as shown in FIG. 27, only the upper and lower end points on both the left and right sides of H are energized for a longer time than other print data. As a result, it is possible to perform printing with excellent print quality in which even the end points are printed correctly.

In the present invention, as shown in FIG. 11, when extending the energization time, it is desirable to extend it by ΔT before and after the normal period. This is to avoid the possibility that when extending only to the front or the rear, a slightly protruding portion may exist on the extended portion, resulting in a somewhat unnatural print form.

〔Effect of the invention〕

According to the present invention, end points and isolated points are extracted, and these parts are printed by controlling the energization time to be extended based on the previous printing conditions, so that missing end points and isolated points are thin. condition can be improved. Therefore, it is possible to provide a thermal printer with excellent printing quality.

[Brief explanation of the drawing]

Figures 1a and b are diagrams explaining the printing part of a thermal printer, c, d, e, and f are diagrams explaining the problems of a conventional thermal printer, and Figure 2 is a diagram explaining the head control state of a conventional thermal printer. Figures 3 and 4
5 is an explanatory diagram of the end point detection state, FIG. 6 and FIG. 7 are explanatory diagrams of the end point energization determination state in the present invention, FIG. 8 is a schematic diagram of the present invention, and FIG. 9 is a diagram of the configuration of the thermal printer. 10 is a detailed diagram of the main part of the present invention, FIG. 10 is an explanatory diagram of the operation of a conventional thermal printer, and FIG.
12 is a thermal head control section, FIG. 13 is a space motor control section, FIG. 14 is a space motor control state diagram, and FIG. 15 is a thermal head energization state diagram. Figure 16 is a configuration diagram of the main parts of the present invention,
7 to 20 are explanatory diagrams of the first embodiment of end point detection, FIGS. 21 and 22 are explanatory diagrams of the second embodiment of end point detection,
Figure 23 shows the buffer and register used in the first embodiment of end point energization determination, Figure 24 is an explanatory diagram of the operation of the first embodiment of end point energization determination, and Figure 25 is used in the second embodiment of end point energization determination. Buffer and register, FIG. 26 is an explanatory diagram of the operation of the second embodiment of end point energization determination, and FIG. 27 is an explanatory diagram of the printing state in the present invention. In the figure, 1 is the platen, 2 is the paper, 3 is the thermal ink ribbon, 4 is the thermal head, and 5 is the thermal ink ribbon.
10 is a heat generating part, 10 is an upper cover, 11 is a paper holder, 12 is a thermal ink ribbon, 13 is a space motor, 14 is a thermal head, 15
is the carrier, 20 is the microprocessor, 21 is the
ROM, 22 is RAM, 23 is input/output port, 2
4 is an output port, 25 is an input port, 26 is a driver, 27 is an approach/escape motor,
28 is a line feed motor, 29 is a photo amplifier, 30 is a micro switch for approach detection, 31 is a left end sensor, 32 is a paper set sensor, 33 is a ribbon end sensor, 4
0 indicates an end point detection section, 41 indicates an end point energization determination section, 42 indicates an energization time control section, and 43 indicates a register section.

Claims (1)

[Claims] 1 A thermal head having a plurality of heating elements arranged adjacent to each other, means for moving the thermal head relative to the print medium, and an end point detection section for detecting end points or isolated points of a print pattern. , means for detecting the presence or absence of a printed pattern near the end point or isolated point from a print pattern printed before the end point or isolated point, and detecting the amount of heat generated by the heating element corresponding to the end point or isolated point at the end point. or a means for controlling according to the presence or absence of a print pattern in the vicinity of an isolated point.