JP2812587B2 - Color thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control for energizing a thermal head of a color thermal printer.

[0002]

2. Description of the Related Art The structure of a conventional example will be described with reference to FIG. FIG. 5 is a block diagram showing a conventional color thermal printer disclosed in, for example, Japanese Patent Application No. 2-1883.

In FIG. 5, 1 is a CPU, 2 is a ROM for storing programs and the like, and 3 is an RA for storing data and the like.
M and 4 are input / output ports and 5 is a counter, which are mutually connected by a bus. 6 is a parallel data input interface, 7 is a P / S circuit, 8 and 9 are line buffers, 10 is a line buffer control circuit, 11 is a reference circuit,
Reference numeral 12 denotes a ROM. Reference numeral 13 denotes a selector, 14 denotes a thermal head, 15 denotes a head temperature detection circuit, and 16 denotes a conduction time control circuit. The reference circuit 11 is composed of a plurality of latch circuits.

Next, the operation of the above-described conventional energization time control will be described with reference to FIGS. 6 and 7. FIG. FIG. 6 and FIG. 7 are a flowchart and a timing chart showing the operation of the energization time control of the conventional color thermal printer.

[0005] In step S 1, the CPU 1 detects the temperature of the thermal head 14 using the head temperature detection circuit 15. This temperature detection data is stored in the RAM 3 through the input / output port 4. In step S2, the printing interval, that is, the recording cycle of each line is obtained and stored in the RAM 3. In step S3, the actual recording dot number of the line to be printed is obtained.

In step S4, the degree of influence of heat on the print line is determined based on the above-described print cycle and the actual number of print dots. In step S5, the above-described influences are accumulated for one row to the current row. Step S6
In, a correction value is obtained based on the calculated cumulative influence degree and the head temperature.

In step S7, a basic energizing time T1 and an adjusted energizing time T
2, T3, and T4 are obtained, and the basic energization time T1 is corrected by the correction value. Then, the recording cycle and the energizing time T1
The data of .about.T4 is output to the conduction time control circuit 16 through the input / output port 4. The energization time control circuit 16 supplies an energization control pulse that is all on according to the energization times T1 to T4 to the thermal head 14. In step S8, the thermal head 14 is energized based on the basic energizing time T1 and the necessary adjustment energizing times T2, T3, and T4. In step S9, the above-described operations from step S2 to step S8 are repeated until printing is completed.

In FIG. 7, (a) shows print data D1,
D2, D3, D4, (b) indicate latch signals. Also,
(C) to (j) exemplify eight typical energization time control patterns corresponding to the state of the surrounding dots for the target dot P of the row L to be printed.

For example, the adjacent dots R _n-1 (L) and R _{n + 1} (L) of the target dot P shown in FIG. 4A and the dots R _n-1 (L-1) and R _{n of the} preceding row are shown. (L-1), R _{n + 1} (L-1),
Dots R _n-1 (L-2), R _n (L-2), R
_When neither _{n + 1} (L-2) is printed, the heating resistor of the target dot P is not affected by heat from other dots, and the energization time is set to the basic value as shown in FIG. The total energization time T1, and the adjustment energization times T2, T3, T4 are all summed.

In addition, the dot R adjacent to the dot of interest P
_{When n-1} (L) performs black printing, the energization time is as shown in FIG.
As shown in (i), the adjustment energization time T2 is turned off. The heating resistor of the dot of interest P is the dot R _n (L
When black printing is performed during -1) and R _{n + 1} (L-1) printing, the energization time T3 is turned off as shown in FIG. 7H. Similarly, depending on the printing state of each dot, the energization time is shown in FIGS.
(E), (d) or (c).

In the energization time control, a correction value is obtained from the cumulative influence degree and the head temperature, and the width of the energization time is controlled. On the other hand, as shown in FIG. 4A, the data is obtained by taking into account the state of the surrounding (reference) dots for the target dot P of the row L to be printed,
Considering the influence of heat from the heating resistors such as the corresponding dots in the preceding row L-1 and the preceding row L-2, the ON / OFF of the energizing times T1, T2, T3, T4 stored in the ROM 12 is considered. Make corrections with reference to the pattern. And, for example, Y
In the case of color printing of (yellow), M (magenta), and C (cyan), the energization control is performed by the same reference method for each color.

[0012]

In the above-described conventional color thermal printer, only the thermal effect of the reference dot of the same color is considered, so that the surface condition of the printing medium (paper) in the overlap printing differs. For this reason, there has been a problem that print quality such as print fading is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a color thermal printer capable of improving printing quality in overprinting.

[0014]

A color sensor according to the present invention is provided.
-Mal printer,Y (yellow) color, M (magenta)
A color server that prints by sequentially superimposing colors and C (cyan) color
In a multi-printer, the line before the line to be printed
The print data R (L-1) and R (L-2) of
To hold the previous line print data holding means and to print Y color
Y color line print data that holds the print data YR (L)
Data holding means and the print data of the line to be printed in M color.
M color line print data holding means for holding the data MR (L);
The print data CR (L) of the line to be printed in C color is stored.
C-color line print data holding means and printing
Attention dot R of line _n (L) depending on the energized state of the surrounding dots
Correction data storage means for storing the corrected correction data;
Is printed in the Y color line print data holding means.
The print data Y of the line to be printed in the Y color held
R _n-1 (L), YR _{n + 1} (L) and the preceding line print data
One line previous print data YR held in the holding means
_n-1 (L-1), YR _n (L-1), YR _{n + 1} (L-
1) and print data YR two lines before _n-1 (L-
2), YR _n (L-2), YR _{n + 1} Based on (L-2)
The correction data stored in the correction data storage means is
The target dot Y of the line to be printed in the Y color with reference to the above.
R _n To control the energization of (L) and print M color,
The Y color mark held in the Y color line print data holding means.
Print data YR _n-1 (L), YR _n (L), Y
R _{n + 1} (L) and held in the M color line print data holding means
Print data MR of the line to be printed in M color
_n-1 (L), MR _{n + 1} (L) and the preceding line print data retention
One line previous print data MR held by the means _n-1
(L-1), MR _n (L-1), MR _{n + 1} (L-1)
Print data MR two lines before _n-1 (L-2), MR
_n (L-2), MR _{n + 1} (L-2)
Refer to the correction data stored in the data storage
Attention dot MR of the line to be printed in the M color _n (L)
When the C color is printed by controlling the energization of
Rows printed in Y color held in print data holding means
Print data YR _n-1 (L), YR _n (L), YR
_{n + 1} (L) stored in the M color line print data holding means.
Print data MR of the printed line of M color
_n-1 (L), MR _n (L), MR _{n + 1} (L) and the above C color
Print the C color held in the line print data holding means
Print data CR of the line to be tried _n-1 (L), CR _{n + 1} (L)
And one line held in the preceding line print data holding means.
Print data CR before in _n-1 (L-1), CR _n (L-
1), CR _{n + 1} (L-1) and print data two lines before
TA CR _n-1 (L-2), CR _n (L-2), CR _{n + 1} (L
-2) and stored in the correction data storage means.
Trying to print the C color with reference to the correction data
Attention dot CR of line _n Energization control for controlling (L) energization
Means.

[0015]

In the present invention,Previous line print data holding means
, The line before the line to be printed and the mark before the line before
Character data R (L-1) and R (L-2) are held. Ma
Further, the Y color line print data holding means prints the Y color.
The print data YR (L) of the row to be tried is held and the
Attempt to print M color by line print data holding means
The line of print data MR (L) is held, and the C color line print data
Mark of the line to be printed in C color by the data holding means.
Character data CR (L) is held. In addition, correction data
The target dot R of the line to be printed is stored by the storage means.
_n The correction data according to the energization state of the surrounding dots in (L) is
It is memorized. Then, the Y color is marked by the energization control means.
When the image is to be printed, the Y color row print data
Print data YR of the line to be printed in Y color
_n-1 (L), YR _{n + 1} (L) and the preceding line print data retention
One line previous print data YR held by the means _n-1
(L-1), YR _n (L-1), YR _{n + 1} (L-1)
Print data YR two lines before _n-1 (L-2), YR
_n (L-2), YR _{n + 1} (L-2)
Refer to the correction data stored in the data storage
The noted dot YR of the line to be printed in the Y color _n (L)
Is controlled and the M color is printed.
Rows printed in Y color held in print data holding means
Print data YR _n-1 (L), YR _n (L), YR
_{n + 1} (L) stored in the M color line print data holding means.
Print data MR of the line to be printed in M color
_n-1 (L), MR _{n + 1} (L) and the preceding line print data retention
One line previous print data MR held by the means _n-1
(L-1), MR _n (L-1), MR _{n + 1} (L-1)
Print data MR two lines before _n-1 (L-2), MR
_n (L-2), MR _{n + 1} (L-2)
Refer to the correction data stored in the data storage
Attention dot MR of the line to be printed in the M color _n (L)
Is controlled, and when printing the C color, the Y color
Y-color printed in the line print data holding means
Line print data YR _n-1 (L), YR _n (L), YR _{n + 1}
(L), and held in the M color line print data holding means.
Print data MR of the line where M color is printed _n-1 (L), M
R _n (L), MR _{n + 1} (L) and the C color line print data storage
Hold in holding means Mark of the line to be printed in C color
Character data CR _n-1 (L), CR _{n + 1} (L) and the preceding line mark
Print data of the previous line held in the character data holding means.
Data CR _n-1 (L-1), CR _n (L-1), CR
_{n + 1} (L-1) and print data CR two lines before
_n-1 (L-2), CR _n (L-2), CR _{n + 1} (L-2)
Based on the correction data stored in the correction data storage means.
Refers to the positive data and arrives at the line to be printed in C color.
Eye dot CR _n The energization of (L) is controlled.

[0016]

【Example】

Embodiment 1 FIG. The configuration of the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a first embodiment of the present invention, in which a CPU 1 to an energization time control circuit 16 are exactly the same as those of the above-described conventional device. In each figure,
The same reference numerals indicate the same or corresponding parts.

In FIG. 1, 17, 18, and 19 are Y
Color, M and C color RAMs, 20 and 21 are P / S circuits, 22 and 23 are line buffers, 24 is a selector,
25 is a reference circuit.

By the way, the preceding line print data holding of the present invention
The means corresponds to the line buffer 8 in the first embodiment of the present invention, and the Y color line print data holding means of the present invention ;
In the first embodiment, the M color line print data holding unit and the C color line print data holding unit are line buffers 9, 22, 2 respectively.
3, the correction data storage means of the present invention corresponds to the ROM 12 in the first embodiment, and the energization control means of the present invention includes the energization time control circuit 16, the line buffer control circuit 10, the selector 24, Reference circuits 11 and 25
It is composed of

Next, the operation of the current supply time control of the first embodiment will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the energization time control according to the first embodiment of the present invention.

Steps S10 to S14 and S16 to S1
8 are performed in steps S1 to S5 and S7 to S7 shown in FIG.
Same as S9. In step S15, a correction value is calculated based on the calculated cumulative degree of influence, the head temperature, and the data for one or two colors before. In step S19, the processing of steps S10 to S18 is repeated until the three colors are completed.

The operation (reference method) of the energization control of each circuit shown in FIG. 1 will be described with reference to FIGS. FIG. 3 is a flowchart showing a reference method according to the first embodiment of the present invention;
FIG. 4 is a diagram for explaining a reference method according to the first embodiment of the present invention.

First, data to be printed is received by the parallel data input interface 6 from an external host. The data to be received is RAM1 which is a buffer memory.
7. One of the Y, M and C colors is received by the RAM 18 and the RAM 19, respectively (steps S20 to S2).
2).

First, since the data in the RAM 17 is parallel in units of 8 bits and the line buffer 9 is a serial input, the data from the first line of the Y color data is P / S
The circuit 7 performs parallel-serial conversion. Then, correction data to be transferred to the thermal head 14 is created (Step S23). In the case of the Y color, since printing is performed directly on a blank sheet, the data of the M color and the C color are not considered.

As shown in FIG. 4B, the correction data for the Y color includes line data YR _n-1 (L) and YR _{n + 1} (L) to be printed in the line buffer 9 and a line buffer. 8
The previous line of data YR _n-1 (L-
1), YR _n (L-1), YR _{n + 1} (L-1), data YR _n-1 (L-2), YR _n (L-2), YR two lines before
_{n + 1} (L-2) and the reference dot pattern (ROM 12
Address. ), An energization time pattern (corresponding to data stored in the ROM 12 in advance) is determined, generated for each dot in accordance with the determined pattern, and written into the line buffer 8.
The above-described reference dot pattern is realized by the reference circuit 11.

As shown in FIG. 7, the energization of the thermal head 14 is performed by energizing each of the thermal heads T1, T2, T
3, data D1, D2, D3, and D4 corresponding to T4 are transferred and energized (step S24). The above operation is
Until the energization control for all the Y colors is completed (step S
25).

As shown in FIG. 4C, the correction data for the M color is line data YR _n-1 (L) and YR _n (L) which have already been printed and are to be printed in the line buffer 9. ,
YR _{n + 1} (L), line data MR _n-1 (L) and MR _{n + 1} (L) to be printed in the line buffer 22, and data M in the previous line held in the line buffer 8.
R _n-1 (L-1), MR _n (L-1), MR _{n + 1} (L-
1) Data MR _n-1 (L-2), MR two lines before
_n (L-2) and MR _{n + 1} (L-2) as the reference dot pattern (corresponding to the address of the ROM 12) and then the energization time pattern (corresponding to the data stored in the ROM 12 in advance). .) Is generated for each dot according to the determined pattern, and is written to the line buffer 8 (step S26). The above reference dot pattern is realized by the reference circuits 11 and 25.

The subsequent energization control is the same as that for the Y color until the energization control for all M colors is completed (step S27,
S28).

As shown in FIG. 4D, the correction data for the C color includes line data YR _n-1 (L), YR _n (L), Y
R _{n + 1} (L) and line buffer 2 already printed
2 line data MR _n-1 (L), M to be printed
R _n (L), MR _{n + 1} (L) and line data CR _n−1 (L), CR
_{n + 1} (L) and the data CR _n-1 (L-1), CR _n (L-1),
CR _{n + 1} (L-1) Data CR _n-1 (L-
2), CR _n (L-2) and CR _{n + 1} (L-2) are reference dot patterns (corresponding to addresses in ROM 12).
After that, a pattern of the energization time (corresponding to data stored in the ROM 12 in advance) is determined, generated for each dot according to the determined pattern, and written into the line buffer 8 (step S29). . In addition,
The above reference dot pattern is realized by the reference circuits 11 and 25.

Thereafter, in the same manner as in the case of the Y color and the M color, the operation is performed until the energization control for all the C colors is completed (steps S30 and S30).
31). Thus, one-sheet printing is completed with the three-color printing of Y, M, and C colors.

The first embodiment of the present invention, as described above,
RAMs 17 to 19 for holding the print data input from the parallel data input interface 6 for each color, P / S circuits 7, 20, 21 for converting the data of the RAMs 17 to 19 from parallel to serial, and holding the serialized data Line buffers 9, 22, and 23, a selector 24 for setting a color to be printed, and a reference circuit 25 for referring to print data of colors before and before the color to be printed are added. The energization of the thermal head 14 is controlled in consideration of the influence and the surface state of the medium to be printed (white paper, one-color printing, two-color printing). Therefore, even in superimposed printing, it is possible to prevent a decrease in image quality such as print fading and to improve the printing quality.

[0031]

According to the present invention, as described above,Y
(Yellow), M (magenta), and C (cyan)
Color thermal printers that print one after the other
Print data before and after the line to be printed.
Previous line print data holding the data R (L-1) and R (L-2)
Data holding means and the print data of the line to be printed in Y color
Y color line print data holding means for holding YR (L);
Holds the print data MR (L) of the line to be printed in color
M color line print data holding means and C color printing
C line print data holding the print data CR (L) of the line
Data holding means and the dot R of interest of the line to be printed. _n
The correction data according to the energization state of the surrounding dots in (L) is recorded.
When printing the Y color,
The Y color line print data holding means
Print data YR of the line to be printed _n-1 (L), YR
_{n + 1} (L) and held in the preceding line print data holding means.
Print data YR one line before _n-1 (L-1), Y
R _n (L-1), YR _{n + 1} (L-1) and two lines before
Print data YR _n-1 (L-2), YR _n (L-2), YR
_{n + 1} (L-2) and is stored in the correction data storage means.
Print the Y color referring to the stored correction data.
The target dot YR of the row to be tried _n Controlling the energization of (L),
When printing M colors, the Y color line print data holding means
Print data YR of the Y-color printed line held in
_n-1 (L), YR _n (L), YR _{n + 1} (L) and the above M color
Print M color held in the line print data holding means
Print data MR of the line to be tried _n-1 (L), MR _{n + 1} (L)
And one line held in the preceding line print data holding means.
Print data MR before in _n-1 (L-1), MR _n (L-
1), MR _{n + 1} (L-1) and print data two lines before
TA MR _n-1 (L-2), MR _n (L-2), MR _{n + 1} (L
-2) and stored in the correction data storage means.
Trying to print the above M color with reference to the correction data
Attention dot MR of row _n Control the energization of (L) and mark C color
When printing, hold in the Y color line print data holding means
Print data YR of the printed line of Y color
_n-1 (L), YR _n (L), YR _{n + 1} (L) and the above M color
M color printed in the line print data holding means
Line print data MR _n-1 (L), MR _n (L), MR _{n + 1}
(L) and C color line printing Held by data holding means
Print data CR of the line to be printed in C color
_n-1 (L), CR _{n + 1} (L) and the preceding line print data retention
One line previous print data CR held by the means _n-1
(L-1), CR _n (L-1), CR _{n + 1} (L-1)
Print data CR two lines before _n-1 (L-2), CR
_n (L-2), CR _{n + 1} (L-2)
Refer to the correction data stored in the data storage
The dot of interest CR of the line to be printed in the C color _n (L)
Energization control means for controlling energization ofWith
The effect that the printing quality can be improved in the image
To play.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of energization time control according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating a reference method according to the first embodiment of the present invention.

FIG. 4 is a diagram for explaining a reference method according to the first embodiment of the present invention and a conventional example.

FIG. 5 is a block diagram showing a conventional color thermal printer.

FIG. 6 is a flowchart showing an operation of controlling a power-on time of a conventional color thermal printer.

FIG. 7 is a timing chart showing a power-on time control operation of the conventional color thermal printer and the first embodiment of the present invention.

[Description of Signs] 1 CPU 7, 20, 21 P / S circuit 8, 9, 22, 23 Line buffer 10 Line buffer control circuit 11, 25 Reference circuit 12 ROM 14 Thermal head 15 Head temperature detection circuit 16 Energizing time control circuit 17, 18, 19 RAM 24 selector

Claims (1)

(57) [Claims] (1)Y (yellow) color, M (magenta) color,
Color thermal for printing by sequentially superimposing C (cyan) colors
In the printer, The print data R of the line before the line to be printed and the line before the line to be printed
(L-1), R (L-2) holding the previous line print data
Holding means, The print data YR (L) of the line to be printed in Y color is stored.
Holding means for holding Y color line print data, The print data MR (L) of the line to be printed in M color is stored.
M color line print data holding means, The print data CR (L) of the line to be printed in C color is stored.
Holding C color line print data holding means; The target dot R of the line to be printed _n Docks around (L)
Correction data that stores correction data according to the power-on state of the
Storage means; When printing the Y color, the Y color line print data holding means
Print data of the line to be printed in Y color held in
Ta YR _n-1 (L), YR _{n + 1} (L) and the preceding line print data
Print data Y of the previous line held in the data holding means
R _n-1 (L-1), YR _n (L-1), YR _{n + 1} (L-
1) and print data YR two lines before _n-1 (L-
2), YR _n (L-2), YR _{n + 1} Based on (L-2)
The correction data stored in the correction data storage means is
The target dot Y of the line to be printed in the Y color with reference to the above.
R _n Controlling the energization of (L), When printing M colors, the Y color line print data holding means
Print data YR of the Y-color printed line held in
_n-1 (L), YR _n (L), YR _{n + 1} (L) and the above M color
Print M color held in the line print data holding means
Print data MR of the line to be tried _n-1 (L), MR _{n + 1} (L)
And one line held in the preceding line print data holding means.
Print data MR before in _n-1 (L-1), MR _n (L-
1), MR _{n + 1} (L-1) and print data two lines before
TA MR _n-1 (L-2), MR _n (L-2), MR _{n + 1} (L
-2) and stored in the correction data storage means.
Trying to print the above M color with reference to the correction data
Attention dot MR of row _n Controlling the energization of (L), When printing C color, the Y color line print data holding
Print data YR of the Y-color printed line held in the column
_n-1 (L), YR _n (L), YR _{n + 1} (L) and the above M color
M color printed in the line print data holding means
Line print data MR _n-1 (L), MR _n (L), MR _{n + 1}
(L), and stored in the C color line print data holding means.
Print data CR of the line to be printed in C color
_n-1 (L), CR _{n + 1} (L) and the preceding line print data retention
One line previous print data CR held by the means _n-1
(L-1), CR _n (L-1), CR _{n + 1} (L-1)
Print data CR two lines before _n-1 (L-2), CR
_n (L-2), CR _{n + 1} (L-2)
Refer to the correction data stored in the data storage
The dot of interest CR of the line to be printed in the C color _n (L)
Energization control means for controlling energization of It is characterized by having
Color thermal printer.