JP2018047578A - Laser recording apparatus, method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a device structure of a laser recording apparatus that records an image by scanning a laser beam while maintaining and improving the quality of recorded images.SOLUTION: A control unit of a laser recording apparatus according to an embodiment preheats a recording medium by applying a laser beam to it so that the temperature in thermosensible recording layers of the recording medium becomes a predetermined preheating temperature equal to or lower than their corresponding threshold temperatures by using a laser beam preheating spot having a first spot diameter, and records on the thermosensible recording layer as a recording target by applying a laser beam so that the temperature in the thermosensible recording layers of the recording target becomes their corresponding threshold temperatures or higher by using a laser beam recording spot having a second spot diameter smaller than the first spot diameter for the preheated thermosensible recording layer.SELECTED DRAWING: Figure 2

Description

  Embodiments described herein relate generally to a laser recording apparatus, a method, and a program.

  2. Description of the Related Art Conventionally, there is known a laser recording apparatus that performs recording by directly irradiating a recording position (laser irradiation position) of a recording medium with laser and utilizing a change in color caused by carbonization of the recording medium or reaction of a color former.

  In order to shorten the recording time in such a laser recording apparatus, there has been proposed an apparatus that includes a heater and performs laser recording after the recording medium is heated and preheated before laser irradiation.

Japanese Patent No. 3040043 JP 2005-138558 A Japanese Patent No. 3509246 JP 2008-179131 A JP 2010-131878 A JP 2004-25739 A

  However, in the above prior art, it is necessary to provide a heating device such as a heater for performing preheating in addition to the laser irradiation device that actually performs writing, which increases the size of the device and increases the cost of the device. It was.

  The present invention has been made in view of the above, and in a laser recording apparatus that performs image recording by scanning a laser beam, the apparatus configuration is simplified and the apparatus is downsized while maintaining and improving the quality of the recorded image. An object of the present invention is to provide a laser recording apparatus, method, and program that can be realized.

The laser recording apparatus according to the embodiment includes a plurality of heat-sensitive materials having different color development threshold temperatures, and a plurality of layers that are stacked such that the threshold temperature of the heat-sensitive material sequentially decreases from the surface layer side irradiated with the laser light toward the lower layer. This is a laser recording apparatus that performs recording by irradiating a recording medium having the heat-sensitive recording layer with laser light.
The control unit irradiates the recording medium with the laser beam so that the temperature in the thermal recording layer of the recording medium becomes a predetermined preheating temperature equal to or lower than a corresponding threshold temperature using the laser beam preheating spot having the first spot diameter. And the pre-heated thermal recording layer using the laser beam recording spot having the second spot diameter smaller than the first spot diameter, the temperature corresponding to the temperature of the thermal recording layer to be recorded corresponds to the threshold value. Recording is performed on the heat-sensitive recording layer to be recorded by irradiating the laser beam so that the temperature is higher than the temperature.

FIG. 1 is an explanatory diagram of a schematic configuration of a recording medium used in the embodiment. FIG. 2 is a basic explanatory diagram of the recording process. FIG. 3 is an explanatory diagram of an example of a temperature change in the coloring layer. FIG. 4 is a schematic configuration block diagram of the laser recording apparatus according to the embodiment. FIG. 5 is an explanatory diagram of the spot diameter changing method of the first aspect. FIG. 6 is an explanatory diagram of the spot diameter changing method of the second mode. FIG. 7 is an explanatory diagram of the spot diameter changing method of the third aspect. FIG. 8 is an explanatory diagram of the spot diameter changing method of the fourth aspect. FIG. 9 is a plan view of a lens holder that holds two types of lenses. FIG. 10 is a process flowchart of a basic recording operation. FIG. 11 is an explanatory diagram of the recording spot scanning operation. FIG. 12 is an explanatory diagram when an image is formed by scanning a preheating spot and a recording spot. FIG. 13 is an explanatory diagram of an example of temperature control of the color developing layer in the second embodiment. FIG. 14 is an explanatory diagram of the correspondence between the time from the end of preheating to the start of recording (standby time) and the concentration. FIG. 15 is an explanatory diagram of an example of temperature control of the coloring layer in the third embodiment. FIG. 16 is a diagram for explaining the correspondence between the laser power density and the density of the recording spot. FIG. 17 is an explanatory diagram of an example of temperature control of the color forming layer in the fourth embodiment. FIG. 18 is a diagram for explaining the correspondence between the recording spot irradiation time and the density. FIG. 19 is an explanatory diagram of the relationship between the scanning speed of the recording spot and the color density. FIG. 20 is an explanatory diagram of an example of temperature control of the color developing layer in the fifth embodiment. FIG. 21 is an explanatory diagram of the relationship between the number of times the recording spot is irradiated with laser light and the density. FIG. 22 is an explanatory diagram of gradation control according to the sixth embodiment. FIG. 23 is a diagram for explaining the correspondence between the diameter and density of the recording spot. FIG. 24 is a processing flowchart of a recording operation according to the seventh embodiment. FIG. 25 is an explanatory diagram of an example of temperature control at the maximum color density (maximum gradation) of the color development layer in the seventh embodiment. FIG. 26 is an explanatory diagram of an example of temperature control at the minimum color density (minimum gradation) of the color development layer in the seventh embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
[1] First Embodiment First, the principle of the first embodiment will be described.
In the laser recording method of the first embodiment, at least heat generated on the protective layer due to laser irradiation is conducted to each layer and the temperature of each layer is changed by controlling how heat is applied by the laser, that is, laser irradiation conditions. This is a recording method in which each layer is selectively colored.

FIG. 1 is an explanatory diagram of a schematic configuration of a recording medium used in the embodiment.
As shown in FIG. 1, the recording medium 10 includes a low-temperature coloring layer 13, a first spacer layer 14, a medium-temperature coloring layer 15, a second spacer layer 16, a high-temperature coloring layer 17, a functional layer 18 and a protective layer on a substrate 12. Layers 19 are stacked in this order. Here, the low-temperature coloring layer 13, the medium-temperature coloring layer 15, and the high-temperature coloring layer 17 constitute a heat-sensitive recording layer (low-temperature heat-sensitive recording layer, medium-temperature heat-sensitive recording layer, and high-temperature heat-sensitive recording layer) on which image recording is performed. The layer 14 and the second spacer layer 16 constitute an intermediate layer that performs heat insulation and heat transfer.

In the above configuration, the substrate 12 holds the low temperature coloring layer 13, the first spacer layer 14, the intermediate temperature coloring layer 15, the second spacer layer 16, the high temperature coloring layer 17, the functional layer 18 and the protective layer 19.
The low temperature coloring layer 13 is a layer containing a temperature indicating material as a heat sensitive material that develops color when its temperature is equal to or higher than the first threshold temperature Tl.

The first spacer layer 14 is a layer that provides a thermal barrier when the low temperature coloring layer 13 is not colored, and suppresses heat transfer from the medium temperature coloring layer 15 side to the low temperature coloring layer 13.
The intermediate temperature coloring layer 15 is a layer including a temperature indicating material as a heat sensitive material that develops a color when the temperature is equal to or higher than the second threshold temperature Tm (> Tl).

The second spacer layer 16 is a layer that provides a thermal barrier when the medium temperature coloring layer 15 is not colored, and suppresses heat transfer from the high temperature coloring layer 17 side to the medium temperature coloring layer 15.
The high-temperature coloring layer 17 is a layer including a temperature indicating material as a heat-sensitive material that develops a color when the temperature becomes equal to or higher than a third threshold temperature Th (> Tm).

  The low-temperature coloring layer 13, the medium-temperature coloring layer 15, and the high-temperature coloring layer 17 are colored in three primary colors when a certain threshold temperature is exceeded using a highly transparent resin such as polyvinyl alcohol, polyvinyl acetate, or polyacryl as a binder. A leuco dye, a leuco dye or other temperature indicating material is used as a coloring material.

  Examples of leuco dyes, leuco dyes as color materials, and other temperature indicating materials include 3,3-bis (1-n-butyl-2-methyl-indol-3-yl) phthalide, 7- (1-butyl-2- Methyl-1H-indol-3-yl) -7- (4-diethylamino-2-methyl-phenyl) -7H-furo [3,4-b] pyridin-5-one, 1- (2,4-dichloro- Phenylcarbamoyl) -3,3-dimethyl-2-oxo-1-phenoxy-butyl- (4-diethylaminophenyl) -carbamic acid isobutyl ester, 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3- Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone = CVL), 3,3-bis (p-dimethylaminophenyl) -6-aminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-nitrophthalide, 3,3-bis3-dimethylamino-7-methylfluorane, 3-diethylamino-7-chlorofluorane, 3- Diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 2- (2-fluorophenylamino) -6 Diethylaminofluorane, 2- (2-fluorophenylamino) -6-di-n-butylaminofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3- (N-ethyl-p-toluidino ) -7- (N-methylanilino) fluorane, 3- (N-ethyl-p-toluidino) -6-methyl-7-anilinofur Lan, 3-N-ethyl-N-isoamylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-N, Coloring dyes such as N-diethylamino-7-o-chloroanilinofluorane, rhodamine B-lactam, 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3-benzylspironaphthopyran can be mentioned. is there.

  Further, as the developer, any acidic substance used as an electron acceptor in the heat-sensitive recording material can be used, for example, an inorganic substance such as activated clay, acidic clay, inorganic acid, aromatic carboxylic acid, its anhydride or Examples thereof include organic developers such as metal salts, organic sulfonic acids, other organic acids, and phenolic compounds. Of these, phenolic compounds are preferred.

  More specific examples of the developer include bis-3-allyl-4-hydroxyphenylsulfone, polyhydroxystyrene, zinc salt of 3,5-di-t-butylsalicylic acid, and 3-octyl-5-methylsalicylic acid. Zinc salt, phenol, 4-phenylphenol, 4-hydroxyacetophenone, 2,2'-dihydroxydiphenyl, 2,2'-methylenebis (4-chlorophenol), 2,2'-methylenebis (4-methyl-6-t -Butylphenol), 4,4'-isopropylidenediphenol (also known as bisphenol A), 4,4'-isopropylidenebis (2-chlorophenol), 4,4'-isopropylidenebis (2-methylphenol), 4 , 4'-ethylenebis (2-methylphenol), 4,4'-thiobis (6-t-butyl-3- Tilphenol), 1,1-bis (4-hydroxyphenyl) -cyclohexane, 2,2'-bis (4-hydroxyphenyl) -n-heptane, 4,4'-cyclohexylidenebis (2-isopropylphenol) And phenolic compounds such as 4,4′-sulfonyldiphenol, salts of the phenolic compounds, salicylic acid anilide, novolac-type phenolic resin, benzyl p-hydroxybenzoate, and the like.

  The spacer layers 14 and 16 provided between the color-developing layers may be made of polypropylene (PP), polyvinyl alcohol (PVA), styrene butadiene copolymer (SBR), polystyrene, polyacryl, or the like.

The functional layer 18 is a layer provided for preventing falsification, for example, a hologram is formed.
The protective layer 19 is a layer for protecting the low temperature coloring layer 13, the first spacer layer 14, the intermediate temperature coloring layer 15, the second spacer layer 16, the high temperature coloring layer 17 and the functional layer 18.

Next, the basic concept of the recording process will be described.
Here, for the sake of easy understanding, a case where the high-temperature coloring layer 17 performs single-color coloring will be described.
In the embodiment, pre-heat treatment and color development treatment are performed by a single laser irradiation apparatus to perform recording.

FIG. 2 is a basic explanatory diagram of the recording process.
In FIG. 2, the protective layer 19, the functional layer 18, and the high-temperature coloring layer 17 are illustrated separately for easy understanding.

First, in the first stage, a preheating spot SH having a spot diameter D1 is irradiated toward the protective layer 19.
Thereby, the light energy supplied to the protective layer 19 is transmitted as thermal energy to the high temperature coloring layer 17 via the functional layer 18, but when the preheating spot SH is irradiated, the preheating region of the high temperature coloring layer 17 is transmitted. The AH temperature is a temperature in the vicinity of the third threshold temperature Th, but since it is still lower than the third threshold temperature Th, no color development occurs.

Next, in a second stage, a recording spot SR having a spot diameter D2 (<D1) is irradiated toward the protective layer 19.
Thereby, the light energy supplied to the protective layer 19 is transmitted to the high temperature coloring layer 17 as thermal energy.

As a result, the temperature of the color development area AR of the high temperature color development layer 17 exceeds the third threshold temperature Th, and the color development area AR having the diameter D3 is in a color development state.
In this case, as long as the spot diameter D1 of the preheating spot SH and the spot diameter D2 of the recording spot SR satisfy the following relationship, and the diameter D3 of the coloring area AR satisfies a desired diameter, It can be set arbitrarily.
D1> D2

  Note that preheating is possible even if D1 ≦ D2, but it is not preferable because the time for preheating takes more than the time for recording.

FIG. 3 is an explanatory diagram of an example of a temperature change in the coloring layer.
In FIG. 3, the vertical axis represents temperature, and the horizontal axis represents elapsed time from the start of processing. In FIG. 3, the high temperature coloring layer 17 is described as an example of the coloring layer.

  The period from the time t0 to the time t1 is the preheating period TM1, and the temperature of the high temperature coloring layer 17 is irradiated with the preheating spot SH and is lower than the third threshold temperature Th that is the coloring threshold temperature. Is very close to the third threshold temperature Th.

  The subsequent period from time t1 to time t2 is the spot irradiation period TM2, and the temperature of the high-temperature coloring layer 17 is gradually increased beyond the third threshold temperature Th, which is the threshold temperature for coloring, when the recording spot SR is irradiated. The color density gradually increases.

  When the time t2 is reached, the irradiation of the recording spot SR is finished, but the temperature remains high due to preheating and remains at a temperature exceeding the third threshold temperature Th, which is the color development threshold temperature, until the time t3. It has become.

  As a result, the region corresponding to the recording spot SR of the high-temperature coloring layer 17 is colored with a coloring density corresponding to the area of the shaded area. That is, the period from time t2 to time t3 is the recording period TM3.

  After time t3, the temperature of the high temperature coloring layer 17 is lower than the third threshold temperature Th, so that the coloring state of the high temperature coloring layer 17 is maintained.

FIG. 4 is a schematic configuration block diagram of the laser recording apparatus according to the embodiment.
The laser recording apparatus 100 effectively emits a laser beam LB for recording to the recording medium 10 placed on the recording stage 101, and a laser beam LB emitted from the laser head unit 102. A driving unit 103 for driving the recording stage 101 for scanning, and a control unit 104 configured as a microcomputer for controlling the laser head unit 102 and the driving unit 103 based on recording image data input from the outside; A housing 105 that supports or houses the laser head unit 102, the drive unit 103, and the control unit 104.

The laser used in the laser head unit 102 is preferably a red to infrared laser having a strong thermal action, and a wavelength band of 800 to 15000 nm is preferable. In particular, a YAG laser, a YVO ₄ laser, a CO ₂ laser, a semiconductor laser or the like used for thermal processing is preferable.

  The reason why the wavelength band of the laser beam LB is set to 800 to 15000 nm is that when the wavelength band of the laser beam LB is less than 800 nm, a special layer that absorbs light and converts it into heat in order to obtain a heat amount for color development is a surface layer. This is because it is necessary to use another color forming agent that generates color by light energy instead of heat.

  Further, when the wavelength band of the laser beam LB exceeds 15000 nm, when the laser beam LB is collected by a lens or the like, the beam waist at the focal point is not sufficiently reduced, and the size of a recordable pixel cannot be reduced. For this reason, it is difficult to record a high-resolution image.

  And the control part 104 controls the power density of the laser beam LB radiate | emitted from the laser head part 102, irradiation time (a scanning speed, the frequency | count of irradiation, etc.), a focus position, a spot diameter, etc. based on the control program memorize | stored beforehand. .

Next, a method for changing the spot diameter between the preheating spot SH and the recording spot SR will be described.
FIG. 5 is an explanatory diagram of the spot diameter changing method of the first aspect.

The laser head unit 102 of the laser recording apparatus 100 corresponding to the spot diameter changing method of the first aspect includes a laser light source 102A that emits a laser beam LB under the control of the control unit 104, and a laser beam emitted by the laser light source 102A. A collimator lens 102B for converting LB into a parallel light beam, a condensing lens 102C for condensing the laser light LB converted into a parallel light beam, and a position of the condensing lens 102C in the optical path of the laser light LB. Is provided with a spot control unit 102D that controls the focal position of the laser beam LB condensed by the laser beam and the spot diameter of the laser beam LB.
In the first aspect, the spot diameter is changed by changing the optical path length to the recording medium after passing through the lens for condensing the laser beam LB.

That is, in the first mode, the spot control unit 102D moves the position of the condenser lens 102C along the optical axis of the laser beam LB incident on the recording medium 10 to change the spot diameter.
More specifically, when the preheating spot SH is irradiated, the spot control unit 102D moves the condenser lens 102C to a position close to the recording medium 10 (a position where the separation distance is short) as shown in FIG. Let As a result, as shown in FIG. 5A, the spot diameter on the surface of the recording medium 10 is increased (corresponding to the spot diameter D1).

  On the other hand, at the time of irradiation of the recording spot SR, the spot control unit 102D moves the condenser lens 102C to a position far from the recording medium 10 (position where the separation distance is long) as shown in FIG. As a result, as shown in FIG. 5B, the spot diameter on the surface of the recording medium 10 becomes small (corresponding to the spot diameter D2).

FIG. 6 is an explanatory diagram of the spot diameter changing method of the second mode.
In the second mode, the spot diameter is changed by moving the stage on which the recording medium is placed and changing the optical path length to the recording medium after passing through the lens for condensing the laser beam LB. is there.
That is, in the second aspect, by moving the stage, the spot diameter is changed by effectively moving the position of the lens along the optical axis of the laser beam LB incident on the recording medium.
The laser recording apparatus 100 corresponding to the spot diameter changing method of the second aspect replaces the spot control unit 102D of the laser head part 102 of the first aspect with the recording stage 101 on the recording stage 101 in the optical axis direction of the laser beam LB. The point is that a stage drive unit 101A for driving is provided.
More specifically, at the time of irradiation with the preheating spot SH, the stage driving unit 101A moves the recording stage 101 to a position close to the condenser lens 102C as shown in FIG. As a result, as shown in FIG. 6A, the spot diameter increases (corresponding to the spot diameter D1).
On the other hand, at the time of irradiation of the recording spot SR, the stage driving unit 101A moves the stage so that the recording medium 10 is far from the condenser lens 102C, as shown in FIG. As a result, as shown in FIG. 6B, the spot diameter becomes small (corresponding to the spot diameter D2).

FIG. 7 is an explanatory diagram of the spot diameter changing method of the third aspect.
The third aspect includes two condensing lenses 102C1 and 102C2 that have the same focal length and condense the laser beam LB, and a position where the condensing lens 102C1 is inserted into the optical path of the laser beam LB, In this case, the spot diameter is changed by switching the position where the lens 102C2 is inserted into the optical path of the laser beam LB.

  The laser recording apparatus 100 corresponding to the spot diameter changing method of the third aspect includes a spot including two condenser lenses 102C1 and 102C2 instead of the condenser lens 102C of the laser head section 102 of the first aspect, and a spot The lens switching unit 102E for switching the condenser lens 102C1 or the condenser lens 102C2 is provided instead of the control unit 102D.

  That is, in the third aspect, the focal lengths are the same condensing lenses 102C1 and 102C2, but the spot diameter is effectively changed by switching the position of insertion into the optical path of the laser beam LB.

  More specifically, when the preheating spot SH is irradiated, the lens switching unit 102E uses a condenser lens 102C1 as the condenser lens to be inserted as shown in FIG. Insert into the optical path of the light LB. As a result, as shown in FIG. 7A, the spot diameter increases (corresponding to the spot diameter D1).

  On the other hand, when irradiating the recording spot SR, the lens switching unit 102E uses the condenser lens 102C2 as the condenser lens to be inserted as shown in FIG. 7B, and the optical path of the laser light LB at a position far from the recording medium 10. Insert inside. As a result, as shown in FIG. 7B, the spot diameter is reduced (corresponding to the spot diameter D2).

FIG. 8 is an explanatory diagram of the spot diameter changing method of the fourth aspect.
The fourth aspect includes a case where the condensing lenses 102C3 and 102C4 that condense two types of laser beams LB having different focal lengths are provided, and the spot diameter is changed by switching the condensing lenses 102C3 and 102C4.

  In the laser recording apparatus 100 corresponding to the spot diameter changing method of the fourth aspect, instead of the two condenser lenses 102C1 and 102C2 of the laser head unit 102 of the fourth aspect, the condenser lenses 102C3 and 102C4 having different focal lengths are used. It is a point with.

That is, in the fourth aspect, the spot diameter is effectively changed by switching the lens that condenses the laser beams LB having different focal lengths.
More specifically, when the preheating spot SH is irradiated, the lens switching unit 102E switches to the condensing lens 102C3 having a long focal length, as shown in FIG. As a result, as shown in FIG. 8A, the spot diameter increases (corresponding to the spot diameter D1).
On the other hand, when the recording spot SR is irradiated, the lens switching unit 102E switches to the condensing lens 103C4 having a short focal length, as shown in FIG. 8B. As a result, as shown in FIG. 8B, the spot diameter is reduced (corresponding to the spot diameter D2).

FIG. 9 is a plan view of a lens holder that holds two types of lenses.
FIG. 9A is a side view, and FIG. 9B is a plan view.
The lens holder 102F shown in FIG. 9 holds two condenser lenses in the third aspect or the fourth aspect described above.

  For example, in the case of the fourth mode, the lens holder 102F includes a disc-shaped holder body 102F1, a condensing lens 102C3 having a long focal length fitted in the holder body 102F1, and a focal length fitted in the holder body 102F. Is provided with a short lens 102C4 and a rotation shaft 102F2 for rotating the holder main body 102F by driving a drive motor of the lens switching unit 102E.

Next, the recording operation will be described.
FIG. 10 is a process flowchart of a basic recording operation.
In the following description, the change method of the fourth aspect described above is used as the change of the spot diameter (switching between the preheating spot SH and the recording spot SR).

First, the lens switching unit 102E drives the drive motor to rotate the rotation shaft 102F, thereby rotating the holder main body 102F1, and driving the condensing lens 102C3 having a long focal length corresponding to the preheating spot SH to the laser beam. Insert into the irradiation path of LB (step S11).
Then, the laser diode of the laser light source 102A is driven, the recording medium 10 is irradiated with the laser beam LB, and pre-heat treatment is performed (step S12).
In this case, the temperature is controlled so that the low temperature coloring layer 13, the medium temperature coloring layer 15, and the high temperature coloring layer 17 of the recording medium 10 are not colored and are as high as possible.

Next, the lens switching unit 102E drives the drive motor again to rotate the rotating shaft 102F2, thereby rotating the holder main body 102F1 to bring the condenser lens 102C4 having a short focal length into the irradiation path of the laser beam LB. Insert (step S13).
Then, the laser diode of the laser light source 102A is driven, and in the region of the high temperature coloring layer 17 corresponding to the region preheated in step S12, according to the recording image pattern and recording density corresponding to the high temperature coloring layer 17, The recording medium 10 is irradiated with the laser beam LB, and control is performed so that the state in which the temperature is equal to or higher than the third threshold temperature Th continues for a time corresponding to the recording density in the coloring region (recording position; dot forming position) of the high temperature coloring layer 17. (Step S14).

  Next, the laser beam LB is irradiated on the recording medium in the region of the intermediate temperature coloring layer 15 corresponding to the region preheated in step S12 according to the recording image pattern and recording density corresponding to the intermediate temperature coloring layer 15. Then, control is performed so that the state in which the temperature is equal to or higher than the second threshold temperature Tm continues in the color development region (recording position; dot formation position) of the intermediate temperature coloring layer 15 for a time corresponding to the recording density (step S15).

Further, the recording medium is irradiated with the laser beam LB in the region of the low-temperature coloring layer 13 corresponding to the region preheated in step S12 according to the recording image pattern and recording density corresponding to the low-temperature coloring layer 13, Control is performed so that the state in which the temperature is equal to or higher than the first threshold temperature Tl in the color development region (recording position; dot formation position) of the low temperature coloring layer 13 continues for a time corresponding to the recording density (step S16).
As a result, a desired image (including characters) can be formed in color and recorded.

  In the above description, recording was not performed while scanning the recording head. However, the preheating spot SH is changed to the recording spot SR after irradiation, and the recording spot SR is scanned in the preheating area. It is also possible.

FIG. 11 is an explanatory diagram of the scanning operation of the recording spot SR.
As shown in FIG. 11, it is also possible to form the desired image (including characters) by scanning the laser beam LB corresponding to the preheating spot SH a plurality of times.

The upper part of FIG. 11 shows a case where the recording spot SR is scanned by scanning the laser beam LB in order to form the character “N”, and the color development area AR corresponding to the character “N” is formed.
Further, the lower part of FIG. 11 shows the case where the recording spot SR is scanned by scanning the laser beam LB in order to form the black square “■” and the color development area AR corresponding to the character “■” is formed. It is.

As described above, a desired image (including characters) can be formed by scanning the laser beam LB corresponding to the preheating spot SH a plurality of times.
Here, when a configuration in which scanning of the laser beam LB is performed on a plurality of floors is adopted, even when a CW (Continuous wave) laser is used as the laser, the time during which the laser beam LB is irradiated and the laser beam LB are irradiated. In this case, it is possible to effectively apply heat energy in a pulsed manner.

FIG. 12 is an explanatory diagram for forming an image by scanning the preheating spot SH and the recording spot SR.
As shown in FIG. 12, not only the recording spot SR but also the preheating spot SH is scanned to preheat the wide range preheat scanning area SHT, and the laser beam LB is configured to form the wide area preheating area AHT. It can also be configured to scan.

More specifically, as shown in FIG. 12A, first, the preheating scanning area SHT having a substantially rectangular shape is formed by scanning the preheating spot SH a plurality of times in the direction of the arrow AX.
As a result, in the coloring layer, a preheating area AH corresponding to the preheating scanning area SHT, and thus a wide area preheating area AHT is formed.
Accordingly, as shown in FIG. 12B, the recording spot SR is scanned a plurality of times in the direction of the arrow BX in an area corresponding to the wide-area preheating area AHT, and as shown in FIG. To record an image.

  Even in this case, when a configuration in which the scanning of the laser beam LB is performed on a plurality of floors is adopted, even when the CW laser is used as the laser, the time during which the laser beam LB is irradiated and the laser beam LB are not irradiated. Since time is generated, it is possible to effectively apply heat energy in a pulsed manner.

[2] Second Embodiment In the above first embodiment, the gradation control has not been described in detail, but in the second embodiment, the recording spot SR is changed from the end of laser irradiation of the preheating spot SH. In this embodiment, the gradation control of pixels to be colored is performed by controlling the time until the laser starts (standby time).

  In the second embodiment, the Nth laser irradiation is performed by irradiating the laser for N times, including the preheating, by increasing the temperature of the color developing layer of the recording medium to a temperature equal to or higher than the color developing threshold temperature. The time from the end of the (N-1) th irradiation to the start of the Nth irradiation is controlled immediately before.

FIG. 13 is an explanatory diagram of an example of temperature control of the color developing layer in the second embodiment.
In FIG. 13, the high temperature coloring layer 17 will be described as an example of the coloring layer.
In FIG. 13, a temperature control curve L21 is, for example, a temperature control curve in the case of the maximum color density (maximum gradation), and a temperature control curve L22 is, for example, a temperature control in the case of the minimum color density (minimum gradation). It is a curve.

For example, in the case of FIG. 13, the period from time t <b> 0 to time t <b> 1 is a period in which the temperature rises due to the first scanning of the preheating spot SH.
The period from the time t1 to the time t2 is a period during which the laser beam LB is not irradiated between the first scanning of the preheating spot SH and the second scanning of the preheating spot SH. This is a state where the temperature of the coloring layer (here, the high temperature coloring layer 17) is lowered.

Further, the period from the time t2 to the time t3 is a period in which the temperature of the coloring layer of the recording medium 10 is increased by the second scanning of the spot for preheating SH, and the preheating period ends at the time t3. Yes.
In the second embodiment, the processing during the preheating period is the same regardless of the density range from the maximum color density to the minimum color density.

  Hereinafter, after the preheating period, the case of the maximum color density and the case of the minimum color density will be described separately.

First, the case where color is developed at the maximum color density will be described.
FIG. 14 is an explanatory diagram of the correspondence between the time from the end of preheating to the start of recording (standby time) and the concentration.
Specifically, the gradation is determined by the elapsed time from time t3 in FIG. 13, that is, the standby time from the end of preheating to the start of recording shown in FIG.

  The standby time WTH in the case of the maximum color density is the standby time WTH << the standby time WTL in the case of the minimum color density. As a result, the temperature of the color development area of the recording medium 10 immediately after the standby time elapses is higher in the case of the maximum color density corresponding to time t4 than in the case of the minimum color density corresponding to time t7. I understand.

  In this case, the time from the start of irradiation of the laser beam LB to the recording spot SR to the end of irradiation is controlled to be constant regardless of the color density, that is, the heating time for color development after the standby time has elapsed. As shown in FIG. 13, it can be seen that the color density increases as the elapsed time from the time t3 when the preheating ends is shorter, and the color density decreases as the time elapses.

Therefore, when irradiation of the laser beam LB of the recording spot SR is started at time t4, the color is developed with the maximum color density.
The period from time t4 to time t6 is a period in which the temperature is rising due to the scanning of the laser beam LB of the recording spot SR. At time t5, the temperature of the high-temperature coloring layer 17 that is the coloring layer exceeds the third threshold temperature Th, and the coloring starts.

At time t6, when the irradiation of the laser beam LB of the recording spot SR is finished, the temperature gradually decreases, and at time t10, the temperature becomes equal to or lower than the third threshold temperature Th.
As a result, the energy of the laser beam LB irradiated from time t5 to time t10 corresponds to the maximum color density.

Next, a case where color is developed with the minimum color density will be described.
As described above, the time from the start of irradiation to the end of irradiation of the laser beam LB of the recording spot SR is constant regardless of the color density, so that when recording with the minimum color density, the recording spot at time t7. Irradiation of the SR laser beam LB is started, and the irradiation ends at time t9.
As a result, the period during which the temperature of the color forming layer exceeds the threshold value is a period from time t8 to time t10, and the energy of the laser beam LB irradiated in this period corresponds to the minimum color density.

  As described above, according to the second embodiment, since the elapsed time from the time when the pre-heating to the color forming layer to be colored is finished is changed according to the color density, the recording density has gradation. It becomes possible to make it.

[3] Third Embodiment The third embodiment is an embodiment in which gradation control of pixels to be colored is performed by controlling the power density of a recording laser.
FIG. 15 is an explanatory diagram of an example of temperature control of the coloring layer in the third embodiment.

In FIG. 15, a temperature control curve L31 is, for example, a temperature control curve in the case of the maximum color density (maximum gradation), and a temperature control curve L32 is, for example, a temperature control in the case of the minimum color density (minimum gradation). It is a curve.
Note that FIG. 15 shows the case where the high-temperature coloring layer 17 is used as the coloring layer.

In the case of FIG. 15, the period from time t <b> 0 to time t <b> 1 is a period in which the temperature rises due to the first scanning of the laser beam LB for the preheating spot SH.
In the period from time t1 to time t2, the laser beam LB between the first scan of the preheating spot SH and the scan of the second preheating spot SH and the laser beam LB of the second preheating spot SH is not irradiated. This is a waiting period, in which the temperature of the recording medium 10 is decreasing.

Further, the period from time t2 to time t3 is a period in which the temperature is rising by the second scanning with the laser beam LB of the preheating spot SH, and the preheating period is ended at the time t3.
In the third embodiment, the process during the preheating period (= t0 to t3) is the same regardless of the density range from the maximum color density to the minimum color density.

  Hereinafter, after the preheating period, the case of the maximum color density and the case of the minimum color density will be described separately.

First, the case where color is developed at the maximum color density will be described.
FIG. 16 is a diagram for explaining the correspondence between the laser power density and the density of the recording spot SR.
Specifically, the gradation is determined by the power density of the laser beam LB of the recording spot SR irradiated for a predetermined time from time t4 in FIG.

  As shown in FIG. 16, the laser beam of the recording spot SR irradiated for a predetermined time (= t7−t4: constant in this embodiment regardless of the color density) from the time t4 when the preheating is finished and the predetermined standby time has elapsed. The higher the LB power density, the more energy is supplied during the time when the temperature is above the threshold temperature, and the higher the color density, and the lower the power density is, the less energy is supplied during the time when the temperature is above the threshold temperature. It turns out that a density | concentration becomes low.

  A period from time t4 to time t7 is a period in which the temperature is increased by the irradiation of the laser beam LB of the recording spot SR. At time t5, color development starts when the temperature of the color development layer exceeds the threshold value.

Then, at the time t7, when the irradiation of the laser beam LB of the recording spot SR is finished, the temperature gradually decreases, and becomes a threshold temperature or lower at the time t10.
As a result, the energy of the laser beam LB irradiated from time t5 to time t9 corresponds to the maximum color density.

Next, a case where color is developed with the minimum color density will be described.
As described above, the power density of the laser beam LB of the recording spot SR is changed according to the color density, but the laser beam LB of the recording spot SR is changed from time t4 when the preheating is finished and a predetermined standby time has elapsed. The irradiation time (t7-t4) is constant regardless of the color density.
Therefore, in the irradiation time of the laser beam LB of the recording spot SR corresponding to the minimum color density at which the power density of the laser beam LB corresponding to the recording spot SR is minimum, the threshold temperature is exceeded at time t6, but recording is performed at time t7. When the time t8 immediately after the irradiation of the laser beam LB of the spot SR is finished, the temperature of the coloring layer becomes lower than the threshold temperature.
As a result, the energy of the laser beam LB irradiated from time t6 to time t8 corresponds to the minimum color density.

  As described above, according to the third embodiment, the laser power density of the recording spot SR with respect to the coloring layer to be colored is changed according to the coloring density, so that the recording density has gradation. It becomes possible to make it.

[4] Fourth Embodiment The fourth embodiment is an embodiment in which gradation control of pixels to be colored is performed by controlling the irradiation time after the laser preheating of the recording spot SR is completed.
FIG. 17 is an explanatory diagram of an example of temperature control of the color forming layer in the fourth embodiment.
In FIG. 17, a temperature control curve L41 is, for example, a temperature control curve for the maximum color density (maximum gradation), and a temperature control curve L42 is, for example, a temperature control for the minimum color density (minimum gradation). It is a curve.
FIG. 17 shows the case where the high temperature coloring layer 17 is used as the coloring layer.
In the case of FIG. 17, the period from time t <b> 0 to time t <b> 1 is a period in which the temperature rises due to the first scanning of the preheating spot SH.
The period from the time t1 to the time t2 is a standby period in which the laser beam LB is not irradiated between the first scanning of the preheating spot SH and the second scanning of the preheating spot SH. The temperature is decreasing.
Further, the period from time t2 to time t3 is a period in which the temperature is increased by the second scanning of the preheating spot SH, and at time t3, the preheating period is ended.
In the fourth embodiment, the processing in the preheating period (= time t0 to t3) is the same regardless of the density range from the maximum color density to the minimum color density.

Hereinafter, after the preheating period, the case of the maximum color density and the case of the minimum color density will be described separately.
First, the case where color is developed at the maximum color density will be described.
FIG. 18 is an explanatory diagram of the correspondence relationship between the irradiation time and the density of the recording spot SR.
Specifically, the gradation is determined by the irradiation time of the recording spot SR determined according to the color density from time t4 in FIG.
When the power density of the laser beam LB of the recording spot SR irradiated from the time t4 when the preheating is finished and a predetermined standby time has elapsed is constant, as shown in FIG. It can be seen that the longer the irradiation time, the greater the amount of energy supplied for color development, and the higher the color density, and the shorter the time, the less the amount of energy supplied during the time above the threshold temperature and the lower the color density.
The period from time t4 to time t8 is the irradiation time of the recording spot SR corresponding to the maximum color density. At time t5, color development starts when the temperature of the color development layer exceeds the threshold value.
Then, at the time t8, when the irradiation of the recording spot SR is finished, the temperature gradually decreases, and becomes the threshold temperature or lower at the time t9.
As a result, the energy of the laser beam LB irradiated from time t5 to time t9 corresponds to the maximum color density.

Next, a case where color is developed with the minimum color density will be described.
As described above, since the irradiation time of the recording spot SR is changed according to the color density from the time t4 when the preheating is finished, the power density of the laser light LB of the recording spot SR corresponds to the minimum color density. The irradiation time of the laser beam LB for the recording spot SR exceeds the threshold temperature at time t5, but the irradiation of the laser beam LB for the recording spot SR is terminated at time t6.
As a result, the temperature of the color developing layer becomes lower than the threshold temperature after the time t7 immediately after.
As a result, the energy of the laser beam LB irradiated from time t5 to time t7 corresponds to the minimum color density.

  As described above, according to the fourth embodiment, the laser irradiation time of the recording spot SR with respect to the coloring layer to be colored is changed according to the coloring density, so that the recording density has gradation. It becomes possible to make it.

[4.1] Modified Example of Fourth Embodiment FIG. 19 is an explanatory diagram of the relationship between the scanning speed of the recording spot SR and the color density.
When attention is paid to the irradiation position where the recording spot SR is present, the irradiation time of the recording spot SR is inversely proportional to the scanning speed of the laser beam LB of the recording spot SR.
Therefore, as shown in FIG. 19, the relationship between the color density and the scanning speed of the recording spot SR is an inversion of the correspondence between the irradiation time of the recording spot SR and the color density in FIG.
Therefore, if the scanning speed is applied in place of the irradiation time of the recording spot SR of the fourth embodiment and the scanning speed is slowed down, the irradiation time of the laser beam LB is substantially increased, and the color density is higher. It can be.
On the contrary, if the scanning speed is increased, the irradiation time of the laser beam LB is substantially shortened and the color density can be lowered.
Therefore, also in the modification of the fourth embodiment, it is possible to give gradation to the recording density as in the fourth embodiment.

[5] Fifth Embodiment In the fifth embodiment, laser irradiation and stop of the recording spot SR are repeated in a pulsed manner at the same period, and gradation control is performed by the number of times of laser irradiation of the recording spot SR. It is an embodiment.

FIG. 20 is an explanatory diagram of an example of temperature control of the color developing layer in the fifth embodiment.
In FIG. 20, a temperature control curve L51 is, for example, a temperature control curve for the maximum color density (maximum gradation), and a temperature control curve L52 is, for example, a temperature control for the minimum color density (minimum gradation). It is a curve.
FIG. 20 shows the case where the high-temperature coloring layer 17 is used as the coloring layer.

In the case of FIG. 20, the period from time t <b> 0 to time t <b> 1 is a period in which the temperature rises due to the irradiation with the preheating spot SH.
The period from time t1 to time t2 is a standby period in which the laser beam LB is not irradiated between the irradiation of the preheating spot SH and the irradiation of the recording spot SR, and the temperature of the recording medium 10 decreases. It is in a state.
When the power density of the laser beam LB is constant, the period from time t0 to time t2 is constant regardless of the color density.

FIG. 21 is an explanatory diagram of the relationship between the number of times of irradiation of the laser beam LB of the recording spot SR and the density.
Then, the gradation is determined by the number of times of irradiation of the recording spot SR determined according to the color density from time t2 in FIG.
In the fifth embodiment, the processing in the preheating period (= t0 to t1) is the same regardless of the density range from the maximum color density to the minimum color density.

  As shown in FIG. 21, as the number of times of irradiation of the recording spot SR irradiated from the time t2 at which the preheating is finished at the time t1 and the predetermined standby time has elapsed, the recording spot SR after the threshold temperature is exceeded is increased. Since the irradiation time becomes longer, the amount of energy supplied for color development increases and the color density increases, and as the number of irradiations decreases, the amount of energy supplied during the time above the threshold temperature decreases and the color density decreases. I understand.

  The number of times of irradiation of the recording spot SR irradiated during the period from time t2 to time t5 is the number of times of irradiation of the recording spot SR corresponding to the maximum color density. At time t3, the temperature of the coloring layer exceeds the threshold value, and coloring starts.

Then, at time t5, when the irradiation of the recording spot SR is finished, the temperature gradually decreases and eventually becomes below the threshold temperature.
As a result, the energy of the laser beam LB irradiated from time t2 to time t6 corresponds to the maximum color density.

Next, a case where color is developed with the minimum color density will be described.
As described above, since the number of times of irradiation with the laser beam LB of the recording spot SR is changed according to the color density from the time t2 when the preheating ends, the power density of the recording spot SR corresponds to the minimum color density with the minimum. In the irradiation time of the recording spot SR, the threshold temperature is exceeded at time t3. However, since there is no subsequent irradiation of the recording spot SR, the temperature of the coloring layer becomes less than the threshold temperature after the time t4 immediately after.
As a result, the energy of the laser beam LB irradiated from time t2 to time t4 corresponds to the minimum color density.

  As described above, according to the fifth embodiment, since the number of times of laser irradiation of the recording spot SR to the coloring layer to be colored is changed according to the coloring density, the recording density has gradation. It becomes possible to make it.

[6] Sixth Embodiment In each of the above embodiments, the diameter of the recording spot SR is constant, but in the sixth embodiment, gradation control is performed by controlling the diameter of the recording spot SR. It is an embodiment in the case of performing.

In the present embodiment, description will be made by taking as an example a case where the irradiation positions of five recording spots SR can be arranged in one pixel region.
FIG. 22 is an explanatory diagram of gradation control according to the sixth embodiment.
FIG. 23 is a diagram for explaining the correspondence between the diameter and density of the recording spot SR.

FIG. 22A is an image diagram of a state visually recognized by the user when the high density region is formed in a square shape, and FIG. 22B is an enlarged view of the pixels constituting the high density region.
FIG. 22C is an image view of the state visually recognized by the user when the low density region is formed in a square shape, and FIG. 22D is an enlarged view of the pixels constituting the low density region. .

In general, as shown in FIG. 23, it can be seen that the density increases as the diameter of the recording spot SR increases.
More specifically, as shown in FIGS. 22 (b) and 22 (d), five recording spots SR can be arranged in each pixel, as shown in FIG. 22 (b). As described above, the diameter of the recording spot SR in the high density area is formed larger than the diameter of the recording spot SR in the low density area shown in FIG. 22D, and the area of the coloring area is the area of the non-coloring area of the background. It is recognized as a high density region.

On the other hand, the diameter of the recording spot SR in the low density area shown in FIG. 22D is formed smaller than the diameter of the recording spot SR in the high density area shown in FIG. This area is relatively smaller than the area of the non-coloring area of the background, and is recognized as a low density area.
As described above, according to the sixth embodiment, since the diameter of the recording spot SR is changed according to the color density, it is possible to give the recording density a gradation.

[7] Seventh Embodiment In the above embodiments, the case of monochromatic color development has been described in principle. However, in the seventh embodiment, C (cyan), Y (yellow), and M (magenta) color development layers. Is an embodiment in which color development is performed in parallel with color development heating and preheating heating.
In this case, in the recording medium shown in FIG. 1, it is assumed that C (cyan) corresponds to the low temperature coloring layer 13, M (magenta) corresponds to the medium temperature coloring layer 15, and Y (yellow) corresponds to the high temperature coloring layer 17. .

Next, the recording operation will be described.
FIG. 24 is a processing flowchart of a recording operation according to the seventh embodiment.
FIG. 25 is an explanatory diagram of an example of temperature control at the maximum color density (maximum gradation) of the color development layer in the seventh embodiment.
FIG. 26 is an explanatory diagram of an example of temperature control at the minimum color density (minimum gradation) of the color development layer in the seventh embodiment.

  In FIG. 25 and FIG. 26, the temperature control curve LC is the temperature control curve of the low temperature coloring layer 13 corresponding to C (cyan), and the degree control curve LM is the temperature of the medium temperature coloring layer 15 corresponding to M (magenta). The temperature control curve LY is a temperature control curve of the high temperature coloring layer 17 corresponding to Y (yellow).

  In the seventh embodiment, with regard to gradation control, the gradation is determined by the waiting times WTH and WTL from the end of preheating to the start of recording, as in the second embodiment. That is, the standby time WTH in the case of the maximum color density is the standby time WTH << the standby time WTL in the case of the minimum color density.

  In the seventh embodiment, the change method of the fourth aspect described above is used as the change of the spot diameter (switching between the preheating spot SH and the recording spot SR).

First, the drive motor of the holder main body 102F1 is driven, and a condensing lens having a long focal length corresponding to the preheating spot SH is inserted into the irradiation path of the laser beam LB (step S21).
Then, the laser diode is driven, the recording medium 10 is irradiated with the laser beam LB, and pre-heat treatment is performed (step S22).
Specifically, the period from time t0 to time t1 shown in FIGS. 25 and 26 is the pre-heat treatment period.

  In this case, the low-temperature coloring layer 13 corresponding to C (cyan), the medium-temperature coloring layer 15 corresponding to M (magenta), and the high-temperature coloring layer 17 corresponding to Y (yellow) are temperatures at which no color develops, and Control the temperature as high as possible.

Next, a condensing lens having a short focal length corresponding to the recording spot SR is inserted into the irradiation path of the laser beam LB (step S23).
Subsequently, it is determined whether or not a standby time corresponding to the print density has elapsed (step S24).

  Specifically, in the case of the maximum color density, as shown in FIG. 25, it is determined whether or not the standby time WTH (= time t1 to time t21) has passed. As shown, it is determined whether or not the standby time WTL (= time t1 to time t22) has elapsed.

  If the standby time corresponding to the print density (for example, standby time WTH, WTL) has not yet elapsed in the determination of step S24 (step S24; No), the standby state is entered.

  If the standby time corresponding to the print density has elapsed in step S24 (step S24; Yes), the laser diode is driven to correspond to the area preheated in step S22 and according to the recorded image pattern. Then, the recording medium is irradiated with the laser beam LB in correspondence with the region for developing three colors of C (cyan), M (magenta), and Y (yellow), and the recording position (dot forming position) of the low-temperature coloring layer 13 is irradiated. The state where the temperature is equal to or higher than the first threshold temperature Tl continues for a time corresponding to the recording density. At the same time, the temperature becomes lower than the second threshold temperature Tm at the recording position (dot formation position) of the medium temperature coloring layer 15 corresponding to M (magenta), and the recording position (dot formation) of the high temperature coloring layer 17 corresponding to Y (yellow). C color development / YM preheating control is performed so as to perform preheating so that the temperature becomes lower than the third threshold temperature Th at (position) (step S25).

Specifically, in the case of the maximum color density, as shown in FIG. 25, the C color / YM preheating control is performed in the period from time t21 to time t4, and in the case of the minimum color density, the color development density is shown in FIG. As described above, the C coloring / YM preheating control is performed during the period from time t22 to time t4.
Thereby, in the low temperature coloring layer 13, C (cyan) is in a colored state.

  Next, at the recording position (dot formation position) of the intermediate temperature coloring layer 15 corresponding to M (magenta), a state where the temperature is equal to or higher than the second threshold temperature Tm continues for a time corresponding to the recording density and also corresponds to M (magenta). M coloring / Y preheating control is performed so as to perform preheating at the recording position (dot formation position) of the high temperature coloring layer 17 so that the temperature becomes lower than the third threshold temperature Th (step S26).

  Specifically, in the case of the maximum color density, as shown in FIG. 25, the M color / Y preheating control is performed in the time from time t4 to time t6, and in the case of the minimum color density, it is shown in FIG. As described above, the M coloring / Y preheating control is performed during the period from time t4 to time t6.

  As a result, in the intermediate temperature coloring layer 15, M (magenta) is in a colored state, and in this region, C (cyan) and M (magenta) are colored.

  Next, Y color development control is performed in which the state where the temperature is equal to or higher than the third threshold temperature Th at the recording position (dot formation position) of the high-temperature coloring layer 17 continues for a time corresponding to the recording density (step S27).

  Specifically, in the case of the maximum color density, as shown in FIG. 25, the Y color control is performed during the period from time t6 to time t7, and in the case of the minimum color density, as shown in FIG. Y color development control is performed during the period from time t6 to time t7.

  As a result, in the high temperature coloring layer 17, Y (yellow) is in a colored state, and in this region, C (cyan), Y (yellow), and M (magenta) are colored.

  As a result, a desired image (including characters) can be formed in color and recorded.

[8] Modified Example of Embodiment [8.1] First Modified Example In addition to the laser beam LB irradiation control, the recording medium 10 itself by air blowing, heating of the recording stage 101, cooling, or the ambient environmental temperature It is possible to further improve the recording speed by performing control.

[8.2] Second Modification In the above description, the case where there are three color-developing layers has been described, but the present invention can be similarly applied to the case of two layers and the case of four or more layers.

[8.3] Third Modification The control unit 104 of the laser recording apparatus 100 of the present embodiment includes a control device such as a CPU, a storage device such as a ROM (Read Only Memory) and a RAM, an HDD, a CD drive device, and the like. The external storage device, a display device such as a display device, and an input device such as a keyboard and a mouse, and has a hardware configuration using a normal computer.

  A program executed by the control unit 104 of the laser recording apparatus 100 of the present embodiment is a file in an installable format or an executable format, and is a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk). And the like recorded on a computer-readable recording medium.

  Further, the program executed by the control unit 104 of the laser recording apparatus 100 according to the present embodiment may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. good. Further, the program executed by the control unit 104 of the laser recording apparatus 100 of the present embodiment may be provided or distributed via a network such as the Internet.

  Further, the program of the control unit 104 of the laser recording apparatus 100 of the present embodiment may be configured to be provided by being incorporated in advance in a ROM or the like.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Recording medium 12 Base material 13 Low temperature coloring layer 14 1st spacer layer 15 Medium temperature coloring layer 16 2nd spacer layer 17 High temperature coloring layer 18 Functional layer 19 Protective layer LB Laser beam LB
SH Preheating spot SR Recording spot

Claims (9)

A plurality of heat-sensitive recording layers, each of which includes a heat-sensitive material having a different color development threshold temperature, and is laminated so that the threshold temperature of the heat-sensitive material sequentially decreases from the surface layer side irradiated with the laser light toward the lower layer. A laser recording apparatus for performing recording by irradiating the recording medium with the laser beam,
Using the laser beam preheating spot having the first spot diameter, the laser beam is applied to the recording medium so that the temperature of the thermal recording layer of the recording medium becomes a predetermined preheating temperature equal to or lower than the corresponding threshold temperature. The heat-sensitive recording layer to be recorded by using the recording spot of the laser beam having a second spot diameter smaller than the first spot diameter on the heat-sensitive recording layer that has been preheated. A laser recording apparatus comprising a control unit that performs recording on the heat-sensitive recording layer to be recorded by irradiating the laser beam so that the temperature in the recording medium is equal to or higher than the corresponding threshold temperature. The controller performs the preheating by scanning the preheating spot a plurality of times.
The laser recording apparatus according to claim 1. The controller performs recording on the thermal recording layer to be recorded by scanning the recording spot a plurality of times.
The laser recording apparatus according to claim 1 or 2. The control unit performs gradation control by changing a density of recording pixels in the thermal recording layer by controlling a time from completion of irradiation of the preheating spot to start of irradiation of the recording spot. The laser recording apparatus according to claim 3. The control unit performs gradation control by changing the density of recording pixels in the thermal recording layer by controlling the laser power density of the recording spot.
The laser recording apparatus according to any one of claims 1 to 3. The control unit performs gradation control by changing the density of the recording pixels in the thermal recording layer by controlling a laser irradiation time or a laser scanning speed of the recording spot.
The laser recording apparatus according to any one of claims 1 to 3. The controller controls the number of scans of the recording pixels in the thermal recording layer by controlling the number of scans of the recording spot when performing recording on the thermal recording layer to be recorded by scanning the recording spot. Tone control by changing the density,
The laser recording apparatus according to any one of claims 1 to 3. A plurality of heat-sensitive recording layers, each of which includes a heat-sensitive material having a different color development threshold temperature, and is laminated so that the threshold temperature of the heat-sensitive material sequentially decreases from the surface layer side irradiated with the laser light toward the lower layer. A method performed by a laser recording apparatus that performs recording by irradiating the recording medium with the laser beam,
Using the laser beam preheating spot having the first spot diameter, the laser beam is applied to the recording medium so that the temperature of the thermal recording layer of the recording medium becomes a predetermined preheating temperature equal to or lower than the corresponding threshold temperature. Preheating by irradiating
The threshold temperature corresponding to the temperature of the thermal recording layer to be recorded by using the laser beam recording spot having a second spot diameter smaller than the first spot diameter for the preheated thermal recording layer. A process of performing recording on the heat-sensitive recording layer to be recorded by irradiating the laser light as described above,
With a method. A laser light source that emits laser light and an optical system that condenses the laser light, each of which includes a heat-sensitive material with a different color development threshold temperature, and from the surface layer irradiated with the laser light from the lower layer side toward the lower layer. A program for controlling by a computer a laser recording apparatus that performs recording by irradiating the recording medium with a plurality of thermal recording layers laminated so that the threshold temperature of the thermal material is sequentially lowered. There,
The computer,
Controlling the laser light source and the optical system, and using a preheating spot of the laser beam having a first spot diameter, the temperature in the thermosensitive recording layer of the recording medium is a predetermined preheating temperature below the corresponding threshold temperature, respectively. Means for preheating by irradiating the recording medium with the laser light so that
The threshold temperature corresponding to the temperature of the thermal recording layer to be recorded by using the laser beam recording spot having a second spot diameter smaller than the first spot diameter for the preheated thermal recording layer. Means for irradiating the laser beam to perform recording on the heat-sensitive recording layer to be recorded;
Program to make it work.

Images