JPH11245432A - Thermal color printer and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance gloss by subjecting a printed a thermal color recording sheet to smoothing. SOLUTION: A thermal color recording sheet 10 is reciprocated three times and printed plane sequentially with yellow, magenta and cyan images by means of a thermal head 21. At the time of recording a cyan image, the recording sheet 10 recorded with a cyan image is heated by means of a heat roller 30 and then the protective layer thereof is pressure cooled by means of a cooling roller 40. Since the protective layer is smoothed during recording of a cyan image, total print time required before ending print operation can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color thermosensitive color printing method and apparatus for performing a smoothing process for increasing gloss after recording a color image.

[0002]

2. Description of the Related Art In a color thermosensitive color printing, a color thermosensitive recording paper is used in which a cyan color thermosensitive layer, a magenta color thermosensitive layer, a yellow color thermosensitive layer, and at least one transparent protective layer are sequentially provided on a support. . Of these three thermosensitive coloring layers, the yellow thermosensitive coloring layer, which is the uppermost layer, has the highest thermal sensitivity and develops color with small heat energy. On the other hand, the cyan thermosensitive coloring layer has the lowest thermal sensitivity because it has a large depth from the surface, and requires a large amount of heat energy to form a color. Further, the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer are provided with fixability by ultraviolet rays or the like.

During color recording (printing), the color thermosensitive recording paper is moved relative to the thermal head, and during this movement, the color thermosensitive recording paper is pressed and heated by the thermal head to change the surface from the uppermost thermosensitive coloring layer. Color recording is performed sequentially. In order to prevent uncolored components remaining in the yellow thermosensitive coloring layer from recording during the recording of the magenta thermosensitive coloring layer, the yellow image is printed and irradiated with violet visible light of 420 nm for fixing. Similarly, after recording the magenta thermosensitive coloring layer, the magenta thermosensitive coloring layer is fixed by irradiating it with ultraviolet rays of 365 nm.

In a thermal head, a cylindrical glaze layer is formed on an alumina substrate, and a plurality of heating elements are linearly formed near the apex of the glaze layer. If the thermal energy during color recording is high, the protective layer is heated to a considerable temperature. If the temperature at which the protective layer separates from the glaze layer is equal to or higher than the glass transition point, substances trapped in the protective layer (for example, an anti-blocking agent) jump out to the surface of the protective layer, so that the surface becomes irregular. Causes fine irregularities. Due to the irregular asperities, the glossiness of the surface of the color thermosensitive recording paper is reduced, resulting in a rough image. In the case of a protective layer mainly composed of PVA (polyvinyl alcohol), the glass transition point is about 70 ° C.
It is.

[0005]

Conventionally, a smoothing apparatus having a heat roller has been used to superimpose a smooth sheet on a printed color thermosensitive recording paper and pass these between a pair of heat rollers to form a color sheet. 2. Description of the Related Art Heat-sensitive recording paper is pressurized and heated. By this smoothing process (glossing process), unevenness on the surface of the color thermosensitive recording paper is smoothed, and the glossiness is improved. However, in this case, it is necessary to perform a glossing process by another device after printing is completed, and since a smooth sheet is superimposed on the printed color thermosensitive recording paper, the smoothing process is not performed. It was troublesome.

On the other hand, for example, Japanese Patent Laid-Open No. 6-2189
As disclosed in Japanese Patent Publication No. 68, it has been proposed to incorporate a heat roller in a printer. However, in this case, since heating and pressurization are simply performed by a heat roller, there is a problem that gloss similar to that of a silver halide photograph cannot be obtained. Further, since the smoothing process is performed after the printing process is completed, there is a problem that the total printing time until the printing is completed becomes long.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color thermal printing method and apparatus capable of obtaining gloss comparable to that of silver halide photographs without prolonging the printing time.

[0008]

According to a first aspect of the present invention, there is provided a color thermosensitive color printing method according to the first aspect.
A color thermosensitive recording paper having first to third thermosensitive coloring layers having different thermal sensitivities and colors to be formed, and a protective layer provided on the third thermosensitive coloring layer located at the uppermost of these layers; Using a thermal head in which a large number of heating elements are formed in a line, the color thermal recording paper is heated by the thermal head in accordance with the image data of each color, and the color is sequentially formed from the third thermosensitive coloring layer. Immediately after recording, the third and second thermosensitive coloring layers are fixed by irradiating a specific electromagnetic ray to each thermosensitive coloring layer to print a color image on color thermosensitive recording paper. In the method, when recording the first thermosensitive coloring layer, the recorded color thermosensitive recording paper is heated under pressure to smooth the protective layer. The smoothing of the protective layer is preferably carried out by heating and heating the color thermosensitive recording paper which has already undergone heat-sensitive coloring, followed by cooling under pressure.

According to a third aspect of the present invention, there is provided a color thermosensitive color printing apparatus, wherein the heating means is disposed downstream of the thermal head in the paper feed direction during recording, and heats the color thermosensitive recording paper; A pressurizing and cooling unit disposed downstream of the paper feeding direction at the time of recording, for pressurizing and cooling the color heating recording paper to smooth it, and the heating unit during thermal recording of the first thermosensitive coloring layer. And control means for driving the pressurizing and cooling means. It is preferable that the heating means is constituted by a heat roller which rotates in contact with the color thermosensitive recording paper, and the pressure cooling means is constituted by a cooling roller which rotates in contact with the color thermosensitive recording paper. Further, a thermal head may be used instead of the heat roller.

[0010]

In FIG. 2, a color thermosensitive recording paper 10 is provided on a support 11 with a cyan thermosensitive coloring layer (first thermosensitive coloring layer) 12, a magenta thermosensitive coloring layer (second thermosensitive coloring layer). 13. Yellow thermosensitive coloring layer (third thermosensitive coloring layer) 1
4, a protective layer 15 is sequentially provided. As the support 11, WP paper or the like having a resin layer formed on both sides of paper is used. The cyan thermosensitive coloring layer 12 has the lowest thermal sensitivity because it is located in a deep layer, and develops cyan when a relatively large heat energy is applied. Magenta thermosensitive coloring layer 1
No. 3 has a medium heat sensitivity and develops magenta color by heating. The yellow thermosensitive coloring layer 14 has the highest thermal sensitivity because it is on the surface side, and develops yellow when a relatively small amount of thermal energy is applied.

In order to prevent color mixing, the magenta thermosensitive coloring layer 13 loses its coloring ability when irradiated with ultraviolet light of approximately 365 nm, and the recorded image is fixed. The yellow thermosensitive coloring layer 14 loses its coloring ability when irradiated with a violet visible light of approximately 420 nm.

The protective layer 15 is a transparent resin layer mainly composed of PVA (polyvinyl alcohol), and prevents each thermosensitive coloring layer from being damaged. The protective layer 15 contains an anti-blocking agent for preventing sticking of the color thermosensitive recording paper, a lubricant for improving slippage, and the like.

In order to increase the difference in thermal sensitivity between the heat-sensitive coloring layers, an intermediate layer is actually formed between the heat-sensitive coloring layers. The protective layer 15 may have a two-layer or three-layer configuration. Further, the thermosensitive coloring layer may be, for example, four or five layers in which a black coloring layer or the like is added. Furthermore, the position of each thermosensitive coloring layer may be changed, for example, the cyan thermosensitive coloring layer may be the uppermost layer.

As shown in FIG. 3, the yellow thermosensitive coloring layer 1
No. 4 has the highest thermal sensitivity, and thus develops color with small heat energy. The cyan thermosensitive coloring layer 12 has the lowest thermal sensitivity and requires large thermal energy. Yellow (Y)
When thermal recording is performed on the pixel of
Heat energy obtained by adding gradation heat energy GY _j to Y is applied to the color thermosensitive recording paper 10. The bias heat energy BY is a heat energy immediately before the yellow thermosensitive coloring layer 14 develops a color, and is a constant value. The gradation heat energy GY _j is determined according to the gradation level of the pixel to be recorded. Since the same applies to magenta M and cyan C, only symbols are given.

In FIG. 1, which shows a color thermal printer,
The color thermosensitive recording paper 10 is moved by an arrow A by a feed roller pair 20.
1 and a pull-back direction indicated by an arrow B1. A thermal head 21 and a platen roller 22 are arranged upstream of the feed roller pair 20 in the printing direction. Further, a cooling roller pair 23 is located downstream of the feed roller pair 20 in the printing direction.
, An optical fixing device 24 and a paper discharge roller pair 25 are arranged. A recording paper sensor 26 for detecting the leading end of the color thermosensitive recording paper 10 is disposed between the feed roller pair 20 and the cooling roller pair 23. A print stage 27 is constituted by the feed roller pair 20, the thermal head 21, and the platen roller 22.

The feed roller pair 20 is composed of a heat roller 30 and a capstan roller 31, and the capstan roller 31 is driven to rotate by a pulse motor 32. The rotation of the pulse motor 32 is controlled by a system controller 34 via a motor driver 33.

The heat roller 30 has a heating element 35 provided in a roller body 30a. The heating element 35 is driven by the system controller 34 via a heater driver 36 and heats the protective layer 15 of the color thermosensitive recording paper 10 to soften it. This heating is performed when the cyan thermosensitive coloring layer 12 is thermally recorded, as described later.

The cooling roller pair 23 includes a metal cooling roller 40 having a smooth peripheral surface and a nip roller 41.
5. Cool and smooth. The nip roller 41 is driven by a pulse motor 32 and is rotated so that the peripheral speed of the feed roller pair 20 is the same as the peripheral speed of the capstan roller 31. In addition, instead of the metal cooling roller 40,
A glass roller having a smooth peripheral surface may be used.
Further, the cooling roller pair 23 may be freely rotated so as to be in a nip state during the smoothing process.

The system controller 34 receives the pulse signal from the recording paper sensor 26 and detects the pulse motor 3 based on the signal.
The number of 2 drive pulses is counted. Then, based on the count value, the feed amount of the recording paper 10 is detected, and the positional relationship between the heating element array 21a and the recording paper 10 is grasped.
The print area, the position to which the recording paper 10 is pulled back, and the like are specified, and the recording paper 10 is reciprocated. In the first recording paper feed in the printing direction A1, a yellow image is recorded on the recording paper 10 by the thermal head 21. A magenta image is sequentially recorded in the second transport, and a cyan image is sequentially recorded in the third transport. Thus, a full-color image can be obtained by three-color surface sequential recording.

The thermal head 21 has a heating element array 21a on its lower surface.
a, a platen roller 22 is pressed through the recording paper 10. As is well known, the heating element array 21a includes a large number of heating elements arranged in a line in the main scanning direction (the axial direction of the platen roller 22). Each heating element is composed of a resistance element. Then, in synchronism with the feeding of the recording paper 10 in the printing direction, each heating element is driven by the printing unit 45 according to the gradation data of the pixel to be printed. As a result, heat energy corresponding to the density of the pixel to be recorded on each thermosensitive coloring layer is given, and the image of each color is reduced to 1%.
It is recorded sequentially line by line.

The optical fixing device 24 includes a yellow fixing lamp 46.
And a magenta fixing lamp 47, which are sequentially arranged in the printing direction. The yellow fixing lamp 46 emits a violet visible ray having an emission peak near 420 nm, and the magenta fixing lamp 47 emits an ultraviolet ray having an emission peak near 365 nm. For example, during yellow image recording, the yellow fixing lamp 46 is turned on, and the yellow thermosensitive coloring layer immediately after thermal recording is optically fixed. Also,
At the time of magenta image recording, the magenta fixing lamp 47 is turned on, and the magenta thermosensitive coloring layer immediately after thermal recording is optically fixed.

Next, based on the flowchart of FIG.
The color printing and the smoothing process will be described with reference to FIG. The color thermosensitive recording paper 10 is fed by a paper feed roller from a paper feed cassette (not shown) and sent to the print stage 27. In the print stage 27, the recording paper 10 is fed in a printing direction indicated by an arrow A1 by the feed roller pair 20. When the leading edge of the recording paper 10 is detected by the recording paper sensor 26, the number of driving pulses of the pulse motor 32 is counted, and the feed amount of the recording paper 10 is measured based on the counted number. Based on the feed amount, a print start and end position, a fixing start and end position, a pull-back position, and the like are specified. Then, first, each heating element of the thermal head 21 is driven via the printing unit 45, and a yellow image is recorded. Also, the yellow fixing lamp 46 is turned on,
During this feeding, the yellow thermosensitive coloring layer 14 is fixed.

When the recording area of the yellow thermosensitive layer reaches the irradiation area of the yellow fixing lamp 46 and the fixing is completed,
The fixing lamp 46 is turned off. Also, feed roller pair 2
0 is reversed, and the recording paper 10 is pulled back in the direction of arrow B1. Then, when the leading end of the recording paper 10 passes through the recording paper sensor 26 and detects this, the retraction is completed and the recording paper 10 is sent in the printing direction. By this second feed in the print direction, as in the case of the yellow image,
Recording of the magenta image and fixing by the magenta fixing lamp 47 are performed, and after these, the recording paper 10 is pulled back.

The cyan image is recorded by the third feeding of the recording paper 10 in the printing direction. When recording the cyan image, the heating element 35 of the heat roller 30 is driven, and the protective layer 15 is softened. Then, the softened protective layer 15 is pressurized and cooled by passing through the cooling roller 40 to be smoothed.

In this smoothing treatment, heat energy that can be heated to a temperature higher than the glass transition point is applied by the heat roller 30 to soften the protective layer 15.
Give to. The glass transition point of the protective layer 15 depends on its composition. However, in the color thermosensitive recording paper (trade name: Thermo Autochrome Paper A-20) currently marketed by the present applicant, PVA is used as the protective layer as a main component, Since the glass transition point is about 70 ° C., the yellow thermosensitive coloring layer 14
When the heat energy required to cause the color to develop to the minimum density is applied, the softening of the protective layer 15 starts. On the other hand, during the smoothing process, the thermal energy for smoothing is set to the bias thermal energy BC of the cyan thermosensitive coloring layer 12 so that the cyan thermosensitive coloring layer 12 not fixed is not colored.
Smaller than.

As described above, the thermal energy for smoothing is appropriately determined within the range of the thermal energy for coloring the yellow thermosensitive coloring layer 14 to the minimum density and the bias thermal energy BC for cyan recording. At this time, the heat energy is determined so as to obtain the best gloss with the least amount of power.

When a cyan image is printed, the magenta fixing lamp 47 is turned on. Thereby, the blank portion of the recording paper 10 is bleached. Then, the discharge roller pair 25
As a result, the recording paper 10 is discharged from the discharge port 48 to a tray or the like (not shown).

When the discharge is completed, the rotation of the pulse motor 32 stops. Further, the heating element 35 of the heat roller 30 is turned off. Thereafter, a print standby state is set.

In the above-described embodiment, one of the feed roller pairs 20 is heated as the heat roller 30. In addition, as shown in FIG. 5, a heat roller pair 51 is provided separately from the feed roller pair 50. It may be provided. The heat roller pair 51 is disposed downstream of the optical fixing device 24 in the printing direction. Further, a cooling roller pair 23 is disposed downstream of and near the heat roller pair 51. Then, by the heat roller pair 51 and the cooling roller pair 23,
When recording a cyan image, a smoothing process is performed. In this case, the feed roller pair 50 does not include the heating element 35 and is formed of a normal roller. In addition, cooling roller pair 2
Since 3 has a function of a discharge roller, the discharge roller pair 25 as shown in FIG. 1 can be omitted. FIG.
The same components as those of the embodiment shown in FIG.
The description is omitted.

In the above embodiment, the recording paper 10 was heated using the heat roller 30 for smoothing. In addition, as shown in FIG. 6, the recording paper 10 was heated using the thermal head 60 for smoothing. May be heated. In this case, the thermal head 60 for smoothing and the platen roller 61 are arranged downstream of the optical fixing device 24 in the printing direction.
Further, a cooling roller pair 23 is provided downstream of the thermal head 60 in the printing direction. This cooling roller pair 23
Performs pressurized cooling for smoothing and paper discharge.

In the above embodiment, the feed roller pairs 20, 5
0 was used to feed the recording paper 10, but in addition to this,
As shown in FIG. 7, the recording paper 71 may be reciprocated by rotating the platen drum 70 forward and reverse. In this case, the thermal head 72 for printing is provided on the peripheral surface of the platen drum 70.
, An optical fixing device 73, a thermal head 74 for smoothing, a cooling roller 75, and a guide roller 76 are arranged in this order. When recording a yellow image and a magenta image, each image is recorded with the smoothing thermal head 74 separated from the platen drum 70. When recording a cyan image, the smoothing process is performed together with the cyan recording while the smoothing thermal head 74 is pressed toward the platen drum 70. Instead of rotating the platen drum 70 forward and backward, a sheet-type recording paper may be fixed to the drum peripheral surface using a known clamp member, and each color may be recorded by rotating in the same direction. In this embodiment, a heat roller may be used instead of the thermal head 74 for smoothing.

The smoothing thermal heads 60, 74
When using the recording paper, the contact area between the recording paper and the thermal head should be located upstream of the recording paper feed direction, so that the contact area on the downstream side of the heating element can be widely secured. Can be. Therefore, the recording paper is pressurized and cooled using this downstream contact area, so that the recording paper can be further smoothed and the glossiness can be increased.

In the above embodiment, the cooling roller 40 is disposed after the heating means such as the heat roller 30 and the thermal heads 60 and 74. However, depending on the type of recording paper, the cooling roller 40 may be smoothed only by pressurizing and heating with the heat roller or the thermal head. In this case, the cooling roller 40 may be omitted. Further, when the recording paper is pressurized and cooled by the cooling roller 40, when the protective layer is softened, the recording paper may be simply heated, so that the recording paper is heated by a non-contact heating means,
Pressurization may be omitted.

In the above-described embodiment, the cut sheet type recording paper has been described. Alternatively, a roll type recording paper that is used by pulling out the recording paper wound up and stored in a roll shape may be used. Also in this case, by performing the smoothing process at the time of cyan recording, the total print time until printing is completed can be shortened.

In the above embodiment, the present invention is applied to a one-head three-pass printer. In addition, the present invention is applied to a three-head one-pass printer having thermal heads for recording yellow, magenta, and cyan colors. May be implemented,
Also in this case, the total printing time is shortened by smoothing the protective layer of the color thermosensitive recording paper following the recording of the first thermosensitive coloring layer, which is the last recording.

[0036]

According to the present invention, when the first thermosensitive coloring layer is recorded, the recorded color thermosensitive recording paper is heated under pressure to smooth the protective layer. The total printing time can be reduced as compared with the type in which the smoothing process is performed in a separate step. Further, the smoothing of the protective layer is carried out by heating the color thermosensitive recording paper which has been subjected to the thermosensitive coloring under pressure and then cooling under pressure, whereby a glossiness comparable to that of a silver halide photograph can be obtained.

Further, by forming one of the feed roller pairs with a heat roller and applying heat energy for smoothing the recording paper, it is not necessary to provide a separate heat roller, and the entirety can be made compact. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a color thermosensitive color printing apparatus of the present invention.

FIG. 2 is an explanatory diagram showing a layer structure of a color thermosensitive recording paper.

FIG. 3 is a graph showing the coloring characteristics of a color thermosensitive recording paper.

FIG. 4 is a flowchart showing a procedure for printing and smoothing a color thermosensitive recording paper.

FIG. 5 is a schematic view showing another embodiment in which a heat roller is separately provided.

FIG. 6 is a schematic view showing another embodiment using a thermal head for smoothing.

FIG. 7 is a schematic view showing another embodiment using a platen drum.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 color thermal recording paper 23 feed roller pair 21, 72 recording thermal head 22 platen roller 23 cooling roller pair 24, 73 optical fixing device 30 heat roller 35 heating element 40 cooling roller 60, 74 smoothing thermal head 70 platen drum

Claims (6)

[Claims] 1. The first to the first, wherein heat sensitivity and color to be developed are different.
A color thermosensitive recording paper having a third thermosensitive coloring layer, a protective layer provided on the uppermost third thermosensitive coloring layer, and a number of heating elements formed in a line. Using a thermal head, the color thermal recording paper is heated by the thermal head in accordance with the image data of each color,
The color thermosensitive recording layer is formed by sequentially irradiating the third and second thermosensitive coloring layers with electromagnetic rays specific to each thermosensitive coloring layer immediately after recording, thereby fixing the thermosensitive coloring layers. In the color thermosensitive coloring printing method for printing a color image on paper, the recording of the first thermosensitive coloring layer is performed by pressurizing and heating the recorded color thermosensitive recording paper to smooth the protective layer. Color thermosensitive printing method. 2. The color thermosensitive color printing method according to claim 1, wherein the smoothing of the protective layer is performed by pressurizing and heating the color thermosensitive recording paper which has been thermosensitively colored, followed by cooling under pressure. 3. The first to third inks having different thermal sensitivities and different colors.
Using a color thermosensitive recording paper having a third thermosensitive coloring layer and a protective layer provided on the uppermost third thermosensitive coloring layer, a large number of heating elements are arranged in the main scanning direction. In a color thermosensitive color printing apparatus that records a full-color image in three color planes sequentially by a thermal head configured to be arranged in a line and a paper feeding unit that feeds a color thermosensitive recording paper in a sub-scanning direction orthogonal to the main scanning direction, A heating means for heating the color thermosensitive recording paper with respect to the thermal head, the heating means being configured to heat the color thermosensitive recording paper; and A pressurizing and cooling unit that pressurizes and cools the color heating recording paper to smooth it, and a control unit that drives the heating unit and the pressurizing and cooling unit during thermal recording of the first thermosensitive coloring layer. Characterized by Color thermal color printing apparatus. 4. The heating means comprises a heat roller which rotates in contact with the color thermosensitive recording paper, and the pressure cooling means comprises a cooling roller which rotates in contact with the color thermosensitive recording paper. The color thermosensitive color printing apparatus according to claim 3. 5. An apparatus according to claim 4, wherein said paper feed means comprises a pair of feed rollers, and one of said pair of feed rollers comprises said heat roller. 6. A color thermosensitive color print according to claim 3, wherein said heating means comprises a thermal head, and said pressure cooling means comprises a cooling roller which rotates in contact with the color thermosensitive recording paper. apparatus.