Multi power type thermal head

Details Multi power type thermal head Multi power type thermal head

2000-06-26

2001-11-20

Le, N. (Department: 2861)

Incremental printing of symbolic information

Thermal marking apparatus or processes

Having driving circuitry for recording means

C347S206000

Reexamination Certificate

active

06320604

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a two-color printing thermal head capable of outputting appropriate, different heating temperatures at the same scanning time to a heat-sensitive substance for developing different colors in response to the heating temperatures, for example, and in particular to an art for giving high power a thermal head for high temperature and low power to a thermal head for low temperature for optimizing the print quality.
To print on heat-sensitive paper with a thermal head, in a related art, as shown in
FIG. 8A
, if print energy (temperature) is made higher than T0, printing is executed in a constant color, such as black, and if print energy is made lower than T0, the print density is reduced, thus the thermal head is not heated for a portion to be skipped in printing. That is, only operation control as to whether or not printing is to be executed depending on the presence or absence of data on one line is performed.
To perform this control, a thermal head provided with an additional history control circuit for limiting a temperature rise caused by heat accumulated in a thermal head substrate also exists for controlling the thermal head at a single temperature, namely, single energy in printing.
In recent years, multi-color heat-sensitive paper printed in black, for example, when printing is executed with a high-temperature thermal head and printed in red, for example, when printing is executed with a low-temperature thermal head has been manufactured. For example, it has been provided as product name MB-23 of Oji Paper Co. Ltd.(JP).
That is, thermal-sensitive paper of this kind develops red, for example, when the print energy (temperature) of a thermal head is T2 and black when the print energy of a thermal head is T1 (T2<T1), as shown in FIG.
8
B. If the print energy is made higher than T1, a whitening phenomenon appears. Thermal-sensitive paper of this kind is available not only with a combination of red and black, but also any other color combination based on low and high print energy.
By the way, when such multi-color heat-sensitive paper is used for executing multi-color printing, for example, red and black printing on a scanning line L
0
, as shown in
FIG. 9A
, with a thermal head in a related art, for example, first a red print data portion needs to be transferred in the current amount corresponding to a low temperature, then again data transfer needs to be executed on the same scanning line L
0
in the current amount corresponding to a high temperature.
To execute two-color (red and black) printing as shown in
FIG. 9B
, likewise a red print data portion is transferred in the current amount corresponding to a low temperature on scanning lines L
1
, L
2
, . . . , then data transfer is executed on the same scanning lines L
1
, L
2
, . . . in the current amount corresponding to a high temperature.
Thus, to handle two types of energy, data transfer is executed twice on one line and each type of energy is set. Since it is necessary to execute data transfer twice on one line, a problem of low print speed is involved.
To solve this problem, a thermal head for making it possible to set different types of energy on one line in one scanning as shown in
FIG. 10
is proposed in U.S. patent application Ser. No. 09/538,283 filed Mar. 30, 2000 (Japanese Patent Application No. Hei 9-302728).
By the way, a control circuit of the thermal head controls high-energy portion data and low-energy portion data separately. Thus, if two types of input energy data are mixed, printing of the low-energy data cannot be executed on low-energy print dots because of the effect of the high energy side, and the print result becomes close to the high-energy side data. For example, the portion to be printed in red is actually printed in a color close to black.
To overcome such a problem, a thermal head adapted so as not to affect printout of low-energy data in the present or absence of high-energy print data in the proximity of print points as shown in
FIG. 11
is also proposed in the Japanese laid open Patent Publication no. 11-208008, filed Aug. 3, 1999 (Japanese Patent Application No. Hei 10-12320).
According to the thermal heads as proposed in the above-mentioned U.S. patent application, as high energy printing control and low energy printing control can be very precisely executed, two-color data can be precisely printed even if the two-color data are mixed.
For example, as shown in
FIG. 9A
, in case a black character area B and a red character area R are respectively blocked on paper, the black area and the red area can be also definitely printed by the control circuit shown in
FIGS. 10
or
11
. However, when a dot of the low energy part exists in a part adjacent to a dot of the high energy part and before and after the dot in case a black character on a red background is printed as shown in
FIG. 9B
, that is, in case a red area R and a black area B are mixed, there is a detect that as printing of a low energy part is developed in color close to printing of a high energy part by the printing of the high energy part, a character and a pattern become indefinite. However, according to the art described above, as a bad effect which high energy data has upon low energy data can be also effectively controlled in case plural types of input energy data are mixed as shown in
FIG. 9B
, clear and precise printing is also enabled in the case shown in FIG.
9
B.
A rewritable print medium, such as an “Aladdin card” (registered trademark) manufactured by Tokyo Magnetic Printing Co. Ltd.(JP), is available. When high energy is given to the rewritable print medium by a thermal head, the medium is printable, but when low energy is given, change is made to a different color and characters, etc., printed on the medium by high energy are erased and characters, graphics, etc., can be again written on the medium by giving high energy.
The control circuits shown in
FIGS. 10 and 11
can also be used for such a medium. In this case, a STROBE
1
signal is set so as to add high energy for printing and a STROBE
2
signal is set so as to give low energy for erasing print characters, etc. In this case, q
1
, q
2
, and q
3
become print erasure data for performing print erasure control. For the medium, it is very strict to set the range of low energy for erasing characters, etc. Thus, preferably the heat history control based on the presence or absence of q
2
, q
3
described above, namely, heating control based on the print erasure data q
2
, q
3
as well as the magnitude of the STROBE
2
signal is added for making energy adjustments.
Thus, the control circuits can also be used with the thermal head for the rewritable medium.
FIG. 12
is an equivalent circuit diagram to the control circuit in FIG.
11
and
FIGS. 13A
to
13
E are logic tables of the control circuit shown in FIG.
12
. In
FIG. 11
, the diode
23
and q
2
input to the NAND circuit
19
have OR relation, thus are shown equivalently as an OR circuit
115
in FIG.
12
A. The output protection circuit
13
in
FIG. 11
is omitted in FIG.
12
A. Thus,
FIG. 11
can be represented equivalently by FIG.
12
A.
In
FIG. 12A
, numeral
100
denotes an FET, numeral
101
denotes an OR circuit, numerals
102
and
103
denote multi-input AND circuits, numeral
104
denotes an AND circuit, numeral
105
denotes a multi-input AND circuit, numerals
106
and
107
denote AND circuits, numerals
108
,
109
,
110
,
111
,
112
,
113
, and
114
denote NAND circuits, numerals
115
,
116
, and
117
denote OR circuits, numerals
118
,
119
,
120
, and
121
denote EOR circuits, and numerals
122
,
123
,
124
,
125
,
126
,
127
,
128
,
129
, and
130
denote inverters.
FIG. 12B
(
1
), (
2
), and (
3
) summarize the unique control portion in the print control range (high energy part), the effect portion of high energy on the print control range (low energy part), and the unique control portion in the print control range (low energy part) shown in FIG.
12
D. Q
1
, Q
2
, Q
3
, and Q
4
in
FIG. 12A
denote latch data a

Affiliated with

Also associated with

Rating

Multi power type thermal head does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Multi power type thermal head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi power type thermal head will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2596041