JP3251989B2 - 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 color heat-sensitive printer using a color heat-sensitive recording material which develops a color with heat energy.

[0002]

2. Description of the Related Art As a color thermosensitive recording material, as described in, for example, JP-A-3-288688, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer are sequentially provided on a support. Things are known. In this color thermosensitive recording material, the lower the thermosensitive coloring layer, the lower the thermal recording sensitivity, and each thermosensitive coloring layer has the property of being fixed by light with a specific electromagnetic ray.

When a multi-color image is thermally recorded on the color thermosensitive recording material, a thermal head having a plurality of heating elements arranged in a line is used, and the color thermosensitive recording material and the thermal head are relatively moved. First, the thermal recording head is used to thermally record the uppermost yellow thermosensitive coloring layer (third layer). After the thermal recording of this yellow image, the yellow thermosensitive coloring layer is light-fixed by irradiating light in a wavelength range that photodecomposes only the uncolored diazonium salt compound of the yellow thermosensitive coloring layer. Next, the magenta thermosensitive coloring layer is thermally recorded on the magenta thermosensitive coloring layer (second layer) using a higher thermal energy than that of the yellow thermosensitive coloring layer, and then only the undeveloped diazonium salt compound of the magenta thermosensitive coloring layer is formed. Is irradiated with light in a wavelength range in which photodecomposition is performed, and light is fixed. Thereafter, using the largest thermal energy, the cyan thermosensitive coloring layer (first layer) is thermally recorded.

[0004]

According to the color thermal recording method, a recording paper is passed three times using one thermal head to thermally record each layer (three-pass method), and three thermal heads are used. There is a method (one-pass method) in which the recording paper is passed through the recording medium and the respective layers are sequentially subjected to thermal recording in one pass. The three-pass method simplifies the configuration by using one thermal head, but requires the recording paper to pass three times,
There is a problem that the recording time becomes longer. In the one-pass method, color printing can be performed in one pass, so that the printing time is shortened. On the other hand, printing is performed almost simultaneously with three thermal heads, so that instantaneous power increases. Therefore, it is necessary to increase the power supply capacity, and there is a problem that the manufacturing cost increases correspondingly. In contrast,
It is conceivable that the thermal head is driven in a time-division manner to reduce the power supply capacity. However, in this case, there is a problem that the cooling time when the thermal head is not driven by the time-division drive becomes long and the thermal efficiency of the head is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a color thermal printer in which the maximum instantaneous power can be kept low without lowering the thermal efficiency of a head in a one-pass system. And

[0006]

In order to achieve the above object, a color thermal printer according to the present invention energizes at least two thermal heads in a time-division manner when recording one pixel, and energizes the time-division energization. The thermal head has a high heat storage effect. Note that the time division
The thermal head to be charged is configured with partial glaze
This part of the glaze is formed thick,
Is preferably increased. In addition, the time-division energizing
The thermal head consists of an alumina substrate, partial glaze and
And a heat insulating layer formed between the
The heat storage effect may be enhanced by the heat insulating layer. Furthermore,
When thermally recording the third to first thermosensitive coloring layers,
The voltage applied when thermally recording the third thermosensitive coloring layer is E1,
The time is T1, and the application is performed when the second thermosensitive coloring layer is thermally recorded.
The voltage is E2, the conduction time is T2, and the first thermosensitive coloring layer is heated.
When the applied voltage for recording is E3 and the energizing time is T3
Then, E1 <E2 <E3, and T1, T2, T3
Preferably, they do not overlap. Also, T1, T2, T3
Instead of overlapping, T1 and T2 and T1 and T3 are
Overlap each other, do not overlap T2 and T3
Is also good.

[0007]

FIG. 2 shows a color thermal printer for recording a color image on a color thermal recording material 10 having three thermal coloring layers. The color thermosensitive recording material 10 is fed at a constant speed by a pair of conveying rollers 11 and 12. The conveying roller pairs 11 and 12 are rotated by a pulse motor 9 (see FIG. 5). 3 between the conveying roller pairs 11 and 12
The platen rollers 13, 14, and 15 are provided in order. Further, on the upper part of each of the platen rollers 13 to 15, from the upstream side in the transport direction of the recording material 10, a thermal head for yellow thermal coloring (first thermal head) 16, a thermal head for magenta thermal coloring (second thermal head) ) 17, and a cyan thermal coloring thermal head (third thermal head) 18 are provided in this order.

Each of the thermal heads 16, 17 and 18 has a vertical configuration and is mounted on a machine frame 19. At the lower ends of the thermal heads 16 to 18, a heating element array 20 is provided. As is well known, the heating element array 20 is formed to be long in a direction orthogonal to the conveying direction of the recording material 10, and a plurality of heating elements 46a, 46b,... Are arranged in a line as shown in FIG. It is configured.

FIG. 3 is a sectional view of the thermal head cut in the sub-scanning direction. For example, a partial glaze 22 and a heating element 46a are provided on a heat-resistant insulating substrate 21 such as alumina. The partial glaze 22 is formed so as to protrude in a cylindrical shape, so that a heated sheet such as a recording paper or an ink ribbon and a thermal head come into good contact with each other. In this embodiment, the partial glaze 22 is formed to be thicker than usual. Since the partial glaze 22 has a low thermal conductivity and a high heat storage property, forming the partial glaze thicker increases the heat storage effect.

The heating element 46a is layered on the partial grace 22, and, as is well known, a resistance layer 23, electrodes 24a and 24b bonded thereon, and a coating on these. And a protective layer 25 for protection. The resistive layer 23 is formed by depositing a resistive material,
It is formed by VD, sintering or the like.

As shown in FIG. 2, a yellow fixing lamp 27 is provided between the first and second thermal heads 16 and 17.
However, between the second and third thermal heads 17 and 18,
A magenta fixing lamp 28 is provided. The yellow fixing lamp 27 is a rod-shaped ultraviolet lamp having an emission peak of approximately 420 nm, and the magenta fixing lamp 28 is an ultraviolet lamp having an emission peak of approximately 365 nm. These lamps 27 and 28 are connected to the thermal heads 16 to 1 respectively.
Since it is disposed in the lamp house formed by the frame 8 and the machine frame 19, the light is reliably blocked by each thermal head and there is no light leakage.

FIG. 4 shows an example of the color thermosensitive recording material 10. On the support 30, a cyan thermosensitive coloring layer 3
1, magenta thermosensitive coloring layer 32, yellow thermosensitive coloring layer 3
3. The protective layer 34 is sequentially provided in a layer shape. Since the deeper the heat-sensitive coloring layers 31 to 33, the higher the coloring heat energy, the three-color heat-sensitive coloring layers 31 to 33 can be selectively recorded by changing the coloring heat energy. Note that an intermediate layer may be provided between the color forming layers.

Since the cyan thermosensitive coloring layer 31 is a deep layer and has the lowest thermal recording sensitivity, it is necessary to apply a large amount of thermal energy. On the other hand, the magenta thermosensitive coloring layer 32 and further the yellow thermosensitive coloring layer 33 need only have a small heat energy near the surface. Accordingly, the present invention applies the yellow thermosensitive coloring layer 33 having the highest thermal recording sensitivity and the magenta thermosensitive coloring layer 32 having the next highest thermal recording sensitivity as shown in FIG. The applied voltages E1 and E2 (E1 <E2) during magenta thermal recording are made smaller than the applied voltage E3 during cyan thermal recording. Furthermore, each energizing time T
The energization times T1, T2, and T3 are shifted so that 1, T2, and T3 do not overlap. That is, each head is time-divisionally driven during the thermal recording time T0 of one pixel. As a result, the instantaneous maximum power during thermal recording can be reduced to the level of the three-pass one-head system.

As shown in FIG. 6, the contents of the energization times T1, T2, and T3 to each heating element for recording one pixel are, as shown in FIG. 6, a bias pulse Pb having a considerably large pulse width and a gradation subsequent thereto. And the number of gradation pulses Pg corresponding to the level. The bias pulse Pb has a higher pulse height and a larger maximum power as the thermosensitive coloring layer has lower thermal recording sensitivity.

FIG. 5 shows an electric circuit of the color thermal printer. The image data input unit 40 includes a color scanner, a color TV camera, and the like.
The image data of three blue colors is sent to the data processing unit 41. The data processing unit 41 performs color correction, gradation correction, and the like on image data of each color. The image data of each color subjected to the image processing is sent to the frame memory 42 and stored in a state of being separated for each color. At the time of thermal recording, the frame memory 42
Thus, the image data of the color to be printed is read line by line and written into the line memory 43.

The image data for one line read from the line memory 43 is sent to a drive data generator 44 and is converted into drive data for each pixel. The drive data includes bias drive data for generating bias heat energy and gradation drive data for generating gradation expression heat energy. The driving data for one line is sent to the head driving unit 45, and a bias pulse Pb and a number of gradation pulses P corresponding to the gradation level are provided for each pixel.
g of each heating element 46 of the heating element array 20.
a to 46n. These heating elements 46a-4
6n are arranged in a line in the main scanning direction, and move relative to the color thermosensitive recording material 10 in the sub-scanning direction. The controller 47 controls the pulse motor 9 via a driver 48 in addition to the sequence control of each part, and rotates the conveying roller pairs 11 and 12 to feed the thermosensitive recording material at a constant speed.

FIG. 7 shows an example of the head driving section 45. One line of serial drive data is sent to the shift register 50 by a clock signal and converted into a parallel signal. The drive data converted into the parallel signal by the shift register 50 is latched by the latch circuit 51 by the latch signal. When the strobe signal is input and the latched signal is “H”, the AND gate 52 outputs an “H” signal. This AND
Each output terminal of the gate 52 includes transistors 53a-5
3n are connected, and when the output terminal of the AND gate 52 is “H”, the corresponding transistor 53a
To 53n are turned ON. These transistors 53a-5
3n is connected to the voltage control circuit 54 via the heating elements 46a to 46n. The voltage control circuit 54 changes the applied voltage according to the switching signal. That is, as shown in FIG. 1, at the time of thermal recording of the yellow thermosensitive recording layer, which is the third layer, the first thermal head 16 is driven by the applied voltage of E1 to thermally record this layer. During thermal recording on the second magenta thermosensitive recording layer, the second voltage is applied by the applied voltage of E2.
The thermal head 17 is driven. During the thermal recording of the first cyan thermosensitive recording layer, the thermal head 18 is driven by the applied voltage of E3.

The drive data for one line is created as follows. First, in order to perform bias heating, “H” drive data is given to all pixels for one line, and serial drive data is obtained. When the drive data is “H”, the corresponding heating element generates heat. Next, the data indicating the first gradation is compared with the image data, and it is determined whether or not to drive the pixel. If the pixel is driven, “H” is set, and if not, “L” is set. This comparison is performed for all pixels on one line, and the image data is converted into serial drive data. The heating elements 46a to 46n are selectively driven by the serial drive data.
Similarly, the data indicating the second gradation is compared with the image data of each pixel, and the drive data is converted as described above.
For example, in the case of 64 gradations, including bias heating,
The driving data for one line is read out in 65 times,
By the 65th strobe signal, each heating element 46a-
46n are selectively driven to express a 64-gradation image.

Next, the operation of this embodiment will be described. At the time of thermal recording, the image data of each color input from the image data input unit 40 is image-processed by the image processing unit 41 and then written in the frame memory 42 in a state of being separated for each color. The heat-sensitive recording material 10 is transported by the transport roller pair 11
It is sent to each of the thermal heads 16, 17, 18.

When the conveying roller pairs 11 and 12 rotate intermittently by a fixed step and the leading end of the recording area of the color thermosensitive recording material 10 reaches the first thermal head 16, thermal recording of a yellow image is started. The image data of the yellow image for one line is read out from the frame memory 42 and written into the line memory 43 once. Next, image data is read from the line memory 43 and sent to the drive data generator 44.

In the thermal recording of the yellow image, as shown in FIG. 1, the applied voltage E1 is set to be the smallest among the three colors. The head driving unit 45 drives each of the heating elements 46a to 46n with a pulse as shown in FIG. 6 to give the bias thermal energy and the gradation expressing thermal energy corresponding to the image data to the color thermosensitive recording material 10. Develop the color to the desired density. When the first line of the yellow image is recorded, the conveying roller pair 11 and 12 are step-rotated by one pixel by the pulse motor 9, and at the same time, the image data of the second line of the yellow image is read from the frame memory 42. Hereinafter, similarly, the second and subsequent lines of the yellow image are thermally recorded on the color thermosensitive recording material 10. When the portion on which the yellow image is thermally recorded reaches the light fixing lamp 25, the yellow thermosensitive coloring layer 33 is light-fixed here.

Next, a magenta image is recorded line by line in the same manner by the second thermal head 17. In the thermal recording of the magenta image, the applied voltage E2 is set to the second lowest. This magenta image is similarly light-fixed by the light fixing lamp 26. During recording of this magenta image, the yellow thermosensitive coloring layer is also heated, but since the coloring ability has already been lost, the yellow thermosensitive coloring layer does not develop color.

Next, a cyan image is thermally recorded line by line by the third thermal head 18. In the thermal recording of the cyan image, the applied voltage E3 is set to be higher than that in the thermal recording of the other colors. This is because the heat-sensitive cyan coloring layer requires considerably high heat energy to perform heat-sensitive coloring. Therefore, no color is formed in a normal storage state, so that light fixing is omitted for the cyan thermosensitive coloring layer. When the thermal recording of each layer is completed by each thermal head, the recorded color thermal recording material 10 is discharged to a tray by a pair of conveying rollers 12.

The energizing time T1, T for each thermal head
As shown in FIG. 1, the T2 and T3 are shifted in order so that they do not overlap with each other, so that the instantaneous maximum power can be suppressed as low as the three-pass one-head system. FIG. 8 shows the heat storage characteristics of the heating element.
Conventionally, the temperature was suddenly decreased as shown by a two-dot chain line. However, in the present embodiment, as shown by a solid line, the partial glaze 22 was formed thick to increase its heat storage effect, so that the temperature was gradually decreased. Thus, the temperature can be easily raised to the thermal recording temperature at the time of energization for the next heat generation, and the thermal efficiency can be increased.

In the above embodiment, three thermal heads are driven in a time-sharing manner. In addition, as shown in FIG.
The thermal head for yellow thermal coloring is driven in a non-divided manner, and the energizing time is set to T1 (T1 = T0). You may. This is because the power consumption of the thermal head for yellow thermosensitive coloring is small. Therefore, since the thermal heads for magenta and cyan are not driven simultaneously, the instantaneous maximum power of the power supply can be reduced to some extent, and the capacity of the power supply can be reduced.

Although the recording material is intermittently fed in the above embodiment, it may be continuously fed. Although the above embodiment is a line printer in which a large number of heating elements are arranged in the main scanning direction and the color thermosensitive recording material is moved in the sub-scanning direction to perform thermal recording, the present invention relates to a thermal head and a color thermosensitive recording material. Can also be used for a serial printer that performs thermal recording by moving two-dimensionally relative to each other. In the above description, the thermal head of each color is used independently, but may be an integrated thermal head as described in JP-A-61-227067. In this case, ultraviolet rays are emitted from slits provided between the heating element lines. As a method to increase the heat storage effect of the head,
In addition to increasing the height of the partial glaze, a heat insulating layer may be formed between the partial glaze and the alumina substrate.

[0027]

As described above, according to the present invention,
Since a head having a high heat storage effect is used as the thermal head driven in a time-division manner, the thermal efficiency can be improved.
In addition, when recording one pixel, the maximum power to each thermal head was changed according to the thermal recording sensitivity and these energization times were shifted so that they did not overlap. It can be as low as the system. Therefore, the power supply capacity can be reduced by this amount, and the manufacturing cost can be reduced. In addition, since the cooling period is extended by the time-division driving, even if a thermal head having a high thermal storage effect is used, an image free from the influence of the thermal history can be obtained. That is, in normal thermal recording, when a head having a large heat storage effect is used, an image may be trailed due to the thermal history of the head, but in the present invention, the cooling time is increased by time-division driving.
Therefore, there is no danger. The thermal head is partially
By making the glaze thicker or
Forming a heat insulating layer between the fuse and the alumina substrate.
As a result, the heat storage effect is enhanced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of applied voltage and energizing time of each thermal head in a color thermal printer of the present invention.

FIG. 2 is a schematic view showing a main part of a color thermal printer embodying the present invention.

FIG. 3 is a sectional view showing a thermal head.

FIG. 4 is an explanatory diagram showing an example of a layer structure of a color thermosensitive recording material.

FIG. 5 is a block diagram illustrating an electrical configuration of the color thermal printer.

FIG. 6 is a waveform chart showing an example of a drive pulse to each thermal head.

FIG. 7 is a circuit diagram showing a head driving unit and a heat generating unit.

FIG. 8 is a diagram showing a heat storage effect of the thermal head.

FIG. 9 is an explanatory diagram showing an example of an applied voltage and an energizing time of each thermal head in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Color thermosensitive recording material 16, 17, 18 Thermal head 20 Heating element array 22 Partial glaze 27, 28 Light fixing lamp 46a-46n Heating element 45 Head drive part

Continuation of the front page (56) References JP-A-61-227067 (JP, A) JP-A-4-267160 (JP, A) JP-A-1-267057 (JP, A) JP-A-4-28565 (JP) JP-A-58-118270 (JP, A) JP-A-63-202465 (JP, A) JP-A-1-118448 (JP, A) JP-A-4-275158 (JP, A) 60-97873 (JP, A) JP-A-6-143644 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/355 B41J 2/325 B41M 5/26

Claims (5)

(57) [Claims] 1. A first to a third thermal head for thermally recording each heat-sensitive coloring layer using a color heat-sensitive recording material having first to third heat-sensitive coloring layers having different coloring colors, After the uppermost third thermosensitive coloring layer is thermally recorded by the first thermal head with the first or second light fixing light source provided between the heads, the third thermosensitive coloring layer is unique. Irradiating the first heat source with the above-mentioned first light source to fix the light, and then heat-recording the second heat-sensitive coloring layer with the second thermal head. In a one-pass type color thermal printer that irradiates with a second lamp and optically fixes this, and then thermally records the first thermal coloring layer with a third thermal head, at least one pixel is recorded. While energizing the two thermal heads in a time-sharing manner, A color thermal printer characterized by using a thermal head having a high thermal storage effect for the time-division energized thermal head. (2) The time-division energized thermal head is
Minute glaze is configured, this partial glaze
Formed thickly to enhance the heat storage effect.
The color thermal printer according to claim 1. (3) The time-division energized thermal head includes:
Formed between alumina substrate and partial glaze
And a heat insulating layer.
The power storage device according to claim 1, wherein the heat storage effect is enhanced.
Ra thermal printer. (4) Heating the third to first thermosensitive coloring layers
When recording, the voltage applied during thermal recording of the third thermosensitive coloring layer
The pressure is set to E1, the energizing time is set to T1, and the second thermosensitive coloring layer is recorded.
The applied voltage for recording is E2, the energizing time is T2,
The applied voltage when thermally recording the thermosensitive coloring layer is E3, and the energizing time
Is T3, E1 <E2 <E3, and T
2. The method according to claim 1, wherein the first, T2 and T3 do not overlap.
3. A color thermal printer according to any one of the above items 3. (5) Heating the third to first thermosensitive coloring layers
When recording, the voltage applied during thermal recording of the third thermosensitive coloring layer
The pressure is set to E1, the energizing time is set to T1, and the second thermosensitive coloring layer is recorded.
The applied voltage for recording is E2, the energizing time is T2,
The applied voltage when thermally recording the thermosensitive coloring layer is E3, and the energizing time
Is T3, E1 <E2 <E 3 and T1
T2 and T1 and T3 overlap, respectively, and T2 and T3
4. The method according to claim 1, wherein the number does not overlap with the number
A color thermal printer according to any one of the preceding claims.