JP6318486B2 - Image processing method and image processing apparatus - Google Patents

Description

  The present invention relates to an image processing method and an image processing apparatus.

  As a method for recording an image on a thermoreversible recording medium, a method of irradiating a laser beam is known. In addition, a laser marker is known as an apparatus that can control the position at which a thermoreversible recording medium is irradiated with laser light. When a thermoreversible recording medium is irradiated with laser light using a laser marker, the photothermal conversion material in the thermoreversible recording medium absorbs light and converts it into heat, so that an image can be recorded.

  However, the laser marker is required to shorten the time required for image recording in order to achieve high throughput.

  Japanese Patent Application Laid-Open No. 2004-151867 records a density calculation step of calculating the density of each character to be recorded from information on the character type, character size and character line width of each character to be recorded, and records each character based on the density of each character An image processing method is disclosed that includes an image recording step of adjusting the irradiation energy of the laser light at the time of recording, and irradiating the laser beam with the adjusted irradiation energy onto the recording medium to record each character.

  However, it is desired to improve the visibility of characters.

  An object of one embodiment of the present invention is to provide an image processing method and an image processing apparatus capable of recording a character with excellent visibility, in view of the problems of the related art.

One embodiment of the present invention includes a step of irradiating a recording medium with a laser beam to record an image including characters of different sizes in an image processing method, and the smaller the size of the predetermined character, Including a step of controlling the scanning speed to be reduced.

One embodiment of the present invention includes a step of irradiating a recording medium with a laser beam to record an image including characters of different sizes in an image processing apparatus. The smaller the size of a predetermined character, Control is performed so as to reduce the scanning speed.

  According to one embodiment of the present invention, it is possible to provide an image processing method and an image processing apparatus capable of recording a character with excellent visibility.

It is a figure explaining the size of a character. It is a figure explaining the character in case a laser beam is irradiated in an overlapping part. It is a figure explaining a character when a laser beam is not irradiated by overlapping in an overlapping part. It is the schematic which shows an example of an image processing apparatus. It is a schematic sectional drawing which shows the 1st example of the layer structure of a thermoreversible recording medium. It is a schematic sectional drawing which shows the 2nd example of the layer structure of a thermoreversible recording medium. It is a schematic sectional drawing which shows the 3rd example of a layer structure of a thermoreversible recording medium. It is a schematic sectional drawing which shows the 4th example of a layer structure of a thermoreversible recording medium.

  Next, the form for implementing this invention is demonstrated with drawing.

  The image processing method includes an image recording step and may further include an image erasing step. The image processing apparatus may include an image recording unit and may further include an image erasing unit.

  The image recording step is a step of recording an image including characters by irradiating a recording medium with laser light, and is performed by an image recording unit.

  Examples of characters include, but are not limited to, kanji, katakana, numbers, alphabets, symbols, figures (for example, logos and barcodes), bag characters, and inverted characters.

  Here, since there are various types of characters, there are often a plurality of characters having different sizes.

  The character size means a product a × b, where a is the height of the character and b is the width of the character (see FIG. 1).

  In general, a laser marker can be recorded by changing the character size by setting the character size (a × b) which is character font data.

  The character font data for laser markers is not particularly limited as long as it is vector scan font data. However, standard font data for one-stroke writing, and line strokes in characters to improve visibility for one-stroke writing. Character font data with a constant interval, character font data for small size with some characters deleted, character font data with overlapping parts removed at intersections / folding parts, outline font data to form bag characters, etc. Can be mentioned.

  At this time, if a plurality of characters of different sizes are recorded in a short time by increasing the scanning speed of the laser beam in order to achieve high throughput, the characters may be distorted, chipped, or crushed depending on the character type. Visibility may be reduced. This is because the follow-up of the galvanometer mirror to the control signal is delayed. In particular, when a small character is recorded at a high speed, the tracking of the galvanometer mirror is significantly delayed.

  Therefore, by controlling so that the scanning speed of the laser beam becomes smaller as the character size becomes smaller, the delay in tracking the galvanometer mirror can be eliminated, and the character with excellent visibility without distortion can be recorded. Can do.

  However, if the scanning speed of the laser beam is too low, the energy density of the laser beam applied to the recording medium becomes excessive, the recording medium is excessively heated, and the line width of the character is increased. Depending on the size and type, the characters may be crushed.

  In order to improve the durability of the thermoreversible recording medium, it is preferable to control so that the output of the laser beam decreases as the character size decreases. If the laser beam output is not controlled to be smaller as the character size is smaller, the energy density of the laser beam irradiated onto the recording medium may become excessive. In particular, a highly distorted character is excessively irradiated with laser light at the distorted portion.

  If the energy density of the laser beam applied to the recording medium becomes excessive, the recording medium will be heated excessively and the line width of the character will increase. Depending on the size and type of the character, the character may be crushed. There is. In particular, when a thermoreversible recording medium having reversibility is used as the recording medium, the recording medium is excessively heated and the constituent material of the thermoreversible recording medium is thermally deteriorated, resulting in a decrease in durability.

  However, if the output of the laser beam is too small, the energy density of the laser beam applied to the recording medium is insufficient, and only characters with low image density can be recorded, so depending on the size and type of characters, Chipping may occur.

  Note that if only the scanning speed of the laser beam is reduced, the energy density of the laser beam applied to the recording medium becomes excessive. For this reason, as the character size decreases, the laser beam scanning speed decreases and the output of the laser beam decreases, so that the energy density of the laser beam applied to the recording medium is set to an appropriate value. As a result, the visibility of characters can be improved and the durability can be improved. In particular, small characters irradiate a plurality of laser beams in a narrow area, and the entire character accumulates heat. Therefore, if the energy density of the laser beam irradiated to the recording medium is not set to an appropriate value, it will be larger than large characters. Durability decreases. In addition, since the durability of small characters and large characters can be made equal, for example, the thermoreversible recording in which the durability of an area where a large character is recorded is high, but the durability of an area where a small character is recorded is low. It can suppress that a medium deteriorates partially.

  The height and / or width of the character is usually 5.0 mm or less, preferably 4.0 mm or less, and more preferably 3.0 mm or less. For characters having a height and / or width of 5 mm or less, the smaller the character size, the greater the effect of character distortion on the character size. For this reason, the visibility of a character can be improved by making the scanning speed of a laser beam small, so that the size of a character becomes small. On the other hand, for characters whose height or width exceeds 5.0 mm, the influence of character distortion on the character size is reduced. For this reason, the smaller the character size, the smaller the effect of improving the character visibility even if the laser beam scanning speed is reduced.

  When the character has an overlapping portion, it is preferable to irradiate the laser beam so that the overlapping portion does not overlap with the laser beam. Specifically, when a character having an overlapping portion where a plurality of drawing lines overlap is recorded, each drawing line is recorded discontinuously in the overlapping portion. When each drawing line is continuously recorded in the overlapping portion, for example, when the overlapping portion is bent, it is difficult to instantaneously change the mirror angle by the operation of the motor. The scanning speed is reduced, excessive energy is applied to the overlapping portion, and repeated recording and erasing of the image may cause local damage to the thermoreversible recording medium.

  A method for continuously recording each drawing line in the overlapping portion is not particularly limited, and a method for recording so that the end point and the start point of each drawing line overlap each other (see FIG. 2).

  In addition, as a method of recording each drawing line discontinuously in the overlapping portion, when a plurality of drawing lines are recorded by irradiating the laser beam, the laser beam irradiation is temporarily interrupted and a plurality of drawing lines are recorded. The method is not particularly limited as long as it is a method of recording lines separately, but a method of recording so that the end points and end points of each drawing line overlap in the overlapping part, and the starting point and starting point of each drawing line overlap in the overlapping part. Recording method, method of recording so that the start point of each drawing line overlaps with a position other than the start point or end point (for example, an intermediate point) in the overlap portion, and the end point of each drawing line in the overlap portion other than the start point or end point A method of recording such that the positions (for example, intermediate points) overlap each other, and two or more of them may be used together (see FIG. 3).

Note that the energy density [J / mm ² ] of the laser beam when the laser beam is irradiated to overlap the overlapping portion is expressed as follows. The laser beam output is P [W] and the laser beam scanning speed is V [mm / s. ], Where the interval of the laser beam in the sub-scanning direction is I [mm], the formula P / (V × I)
It is represented by

On the other hand, the energy density [J / mm ² ] of the laser light in the case where the laser beam is not irradiated overlapping the overlapping portion, the output of the laser light is P [W], and the scanning speed of the laser light is V [mm / s]. When the spot diameter illuminated on the recording medium arranged perpendicular to the laser beam irradiation direction is r [mm], the formula P / (V × r)
It is represented by

  A method for changing the energy density of the laser light is not particularly limited, but a method for changing the output of the laser light and / or the scanning speed of the laser light is preferable.

  The method for changing the scanning speed of the laser beam is not particularly limited, and examples thereof include a method for changing the rotation speed of the motor that is responsible for the operation of the scanning mirror.

  The method for changing the output of the laser beam is not particularly limited, and examples thereof include a method for changing the set value of the laser beam output, and a method for changing the pulse duration in the case of a pulsed laser.

  As a method of changing the setting value of the laser light output, there is a method of changing the setting value of the laser light output by the image recording unit.

  As a method for changing the time width of the pulse, there is a method of changing the time width of the pulse by the image recording unit.

  The output of the laser beam irradiated when recording an image is usually 1 W or more, preferably 3 W or more, and more preferably 5 W or more. If the output of the laser beam irradiated when recording an image is less than 1 W, it may take time to record the image. Further, the output of the laser beam irradiated when recording an image is usually 200 W or less, preferably 150 W or less, and more preferably 100 W or less. When the output of the laser beam irradiated when recording an image exceeds 200 W, the laser marker may be increased in size.

  The scanning speed of the laser beam irradiated when recording an image is usually 300 mm / s or more, preferably 500 mm / s or more, and more preferably 700 mm / s or more. If the scanning speed of the laser beam irradiated when recording an image is less than 300 mm / s, it may take time to record the image. In addition, the scanning speed of the laser light irradiated when recording an image is usually 15000 mm / s or less, preferably 10,000 mm / s or less, and more preferably 8000 mm / s or less. If the scanning speed of the laser beam irradiated when recording an image exceeds 15000 mm / s, it may be difficult to form a uniform image.

  The spot diameter of the laser beam irradiated when recording an image is usually 0.02 mm or more, preferably 0.1 mm or more, and more preferably 0.15 mm or more. When the spot diameter of the laser beam irradiated when recording an image is less than 0.02 mm, the line width of the image becomes narrow and visibility may be lowered. Further, the spot diameter of the laser beam irradiated when recording an image is usually 3.0 mm or less, preferably 2.5 mm or less, and more preferably 2.0 mm or less. If the spot diameter of the laser beam irradiated when recording an image exceeds 3.0 mm, the line width of the image becomes thick, and adjacent lines may overlap, making it difficult to record a small size image.

The light source of the laser beam irradiated when recording an image is not particularly limited, and examples thereof include a semiconductor laser, a YAG laser, a fiber laser, and a CO ₂ laser. Among these, a semiconductor laser is preferable because it has a wide wavelength selectivity, a light source itself is small, and the size and cost of the apparatus can be reduced.

  When recording an image, the wavelength of laser light emitted from a semiconductor laser, YAG laser, or fiber laser is usually 700 nm or more, preferably 720 nm or more, and more preferably 750 nm or more. When recording an image, if the wavelength of laser light emitted from a semiconductor laser, YAG laser, or fiber laser is in the visible light region of less than 700 nm, the contrast of the image recorded on the recording medium may be reduced, or the recording medium May be colored. When recording an image, if the wavelength of laser light emitted from a semiconductor laser, YAG laser, or fiber laser is in the ultraviolet region, the recording medium may be easily deteriorated. In addition, the photothermal conversion material added to the recording medium requires a high decomposition temperature in order to ensure durability. When an organic dye is used as the photothermal conversion material, a photothermal conversion material having a high decomposition temperature and a long absorption wavelength is obtained. Is difficult. For this reason, when recording an image, the wavelength of the laser light emitted from the semiconductor laser, YAG laser, or fiber laser is usually 1500 nm or less, preferably 1300 mm or less, and more preferably 1200 nm or less. preferable.

When recording an image, the wavelength of the laser light emitted from the CO ₂ laser is 10.6 μm in the far-infrared region, and without adding an additive for absorbing the laser light and generating heat, Laser light is absorbed by the surface of the recording medium. Even if the additive uses a laser beam having a wavelength in the near-infrared region, visible light may be absorbed even though it is slightly, so a CO ₂ laser that does not require an additive is added to the recording medium. A decrease in contrast of the recorded image can be suppressed.

  When recording an image on a thermoreversible recording medium, the image erasing step is a step of erasing the image recorded on the thermoreversible recording medium by heating the thermoreversible recording medium on which the image is recorded. Done.

  The image erasing step preferably includes a width direction parallelizing step, a length direction light distribution controlling step, and a beam size adjusting step. The image erasing unit preferably includes a width direction parallelizing unit, a length direction light distribution control unit, and a beam size adjusting unit.

  The method for heating the thermoreversible recording medium is not particularly limited, but a non-contact heating method using a laser beam, hot air, hot water, infrared heater, etc., a contact heating method using a thermal head, hot stamp, heat block, heat roller, etc. Etc. In particular, when a distribution line is assumed, a method of irradiating a thermoreversible recording medium with a circular beam of laser light is preferable.

  The output of the laser beam irradiated when erasing the image is usually 5 W or more, preferably 7 W or more, and more preferably 10 W or more. If the output of the laser beam irradiated when erasing the image is less than 5 W, it may take time to erase the image. Further, the output of the laser beam irradiated when erasing the image is usually 200 W or less, preferably 150 W or less, and more preferably 100 W or less. If the output of the laser beam irradiated when erasing the image exceeds 200 W, the laser device may be increased in size.

  The scanning speed of the laser beam irradiated when erasing the image is usually 100 mm / s or more, preferably 200 mm / s or more, and more preferably 300 mm / s or more. If the scanning speed of the laser beam irradiated when erasing the image is less than 100 mm / s, it may take time to erase the image. Further, the scanning speed of the laser beam irradiated when erasing the image is usually 20000 mm / s or less, preferably 15000 mm / s or less, and more preferably 10,000 mm / s or less. If the scanning speed of the laser beam irradiated when erasing the image exceeds 20000 mm / s, it may be difficult to erase the image uniformly.

  The spot diameter of the laser beam irradiated when erasing the image is usually 0.5 mm or more, preferably 1.0 mm or more, and more preferably 2.0 mm or more. If the spot diameter of the laser beam irradiated when erasing the image is less than 0.5 mm, it may take time to erase the image. Further, the spot diameter of the laser beam irradiated when erasing the image is usually 14.0 mm or less, preferably 10.0 mm or less, and more preferably 7.0 mm or less. If the spot diameter of the laser beam irradiated when erasing an image exceeds 14.0 mm, the output may be insufficient and an image erasing failure may occur.

The light source of the laser beam irradiated when erasing the image is not particularly limited, and examples thereof include a semiconductor laser, a YAG laser, a fiber laser, and a CO ₂ laser. Among these, a semiconductor laser array in which a plurality of semiconductor lasers are linearly arranged is preferable from the viewpoint of wide wavelength selectivity, small light source itself, and miniaturization and cost reduction of the apparatus.

  The number of semiconductor lasers included in the semiconductor laser array is usually 3 to 300, preferably 10 to 100. If the number of semiconductor lasers included in the semiconductor laser array is 2 or less, the output of the laser beam may be reduced. If it is 301 or more, a large-scale cooling device for cooling the semiconductor laser array is required. Equipment costs may increase.

  The length of the light source of the semiconductor laser array is usually 1 to 50 mm, and preferably 3 to 15 mm. If the length of the light source of the semiconductor laser array is less than 1 mm, the output of the laser beam may decrease. If the length exceeds 50 mm, a large-scale cooling device for cooling the semiconductor laser array is required, and the device cost increases. Sometimes.

  When erasing an image, the wavelength of the laser light emitted from the semiconductor laser array is usually 700 nm or more, preferably 720 nm or more, and more preferably 750 nm or more. When erasing an image, if the wavelength of the laser light emitted from the semiconductor laser array, YAG laser, or fiber laser is in the visible light region of less than 700 nm, the contrast of the image recorded on the thermoreversible recording medium may decrease. The thermoreversible recording medium may be colored. When erasing an image, if the wavelength of the laser beam emitted from the semiconductor laser array is in the ultraviolet region, the thermoreversible recording medium may be easily deteriorated. In addition, the photothermal conversion material added to the thermoreversible recording medium requires a high decomposition temperature in order to ensure durability. When an organic dye is used as the photothermal conversion material, the photothermal conversion material has a high decomposition temperature and a long absorption wavelength. Hard to get. For this reason, when erasing an image, the wavelength of the laser light emitted from the semiconductor laser array is usually 1500 nm or less, preferably 1300 mm or less, and more preferably 1200 nm or less.

  The width direction parallelization step is a step of making the beam in the width direction of the laser light irradiated from the semiconductor laser array parallel to form a line beam, and is performed by the width direction parallelization unit.

  Although it does not specifically limit as a width direction parallelization part, The combination of one single-sided convex cylindrical lens, a some convex cylindrical lens, etc. are mentioned.

  Laser light emitted from the semiconductor laser array has a larger diffusion angle in the width direction than in the length direction, and the width of the laser beam emitted from the semiconductor laser array is increased by the proximity of the width direction parallelizing portion to the emission surface of the semiconductor laser array. This can be suppressed and the lens can be made small.

  The length direction light distribution control step is a step in which the linear beam formed in the width direction parallelization step is longer than the length of the light source of the semiconductor laser array and is made uniform in the length direction. This is performed by the distribution control unit.

  The length direction light distribution control unit is not particularly limited, and examples thereof include a combination of two spherical lenses, an aspherical cylindrical lens (length direction), and a cylindrical lens (width direction).

  Examples of the aspheric cylindrical lens (length direction) include a Fresnel lens, a convex lens array, and a concave lens array.

  The lengthwise direction light distribution uniformizing portion is disposed on the exit surface side of the widthwise parallelizing portion.

  The beam size adjustment step is a step of adjusting the length and / or width of a line beam having a uniform light distribution in the length direction on the thermoreversible recording medium, which is longer than the length of the light source of the semiconductor laser array. This is performed by the beam size adjustment unit.

  The beam size adjusting unit is not particularly limited, and examples thereof include changing the focal length of a cylindrical lens and a spherical lens, changing the lens installation position, changing the distance between the apparatus and the workpiece of the thermoreversible recording medium, and the like.

  The length of the line beam after the beam size is adjusted is usually 10 to 300 mm, and preferably 30 to 160 mm. If the length of the linear beam after the beam size is adjusted is less than 10 mm, the area where the image is erased may become narrow. If the length exceeds 300 mm, the area where the image cannot be erased is also irradiated with laser light. Sometimes.

  The ratio of the length of the line beam after the beam size is adjusted with respect to the length of the light source of the semiconductor laser array is preferably 2 or more, and more preferably 3 or more. If the ratio of the length of the line beam after the beam size is adjusted to the length of the light source of the semiconductor laser array is less than 2, the light source of the semiconductor laser array is lengthened in order to secure an area for erasing the image. Device cost and device size may increase.

  The width of the line beam after the beam size is adjusted is usually 0.1 to 10 mm, preferably 0.2 to 5 mm. If the width of the line beam after the beam size is adjusted is less than 0.1 mm, the heating time is shortened, and the performance of erasing the image may be deteriorated. If it exceeds 10 mm, the heating time is lengthened. Extra energy may be applied to the thermoreversible recording medium.

  The output of the line beam after the beam size is adjusted is usually 10 W or more, preferably 20 W or more, and more preferably 40 W or more. If the output of the line beam after the beam size is adjusted is less than 10 W, it may take time to erase the image. Further, the output of the line beam after the beam size is adjusted is usually 500 W or less, preferably 200 W or less, and more preferably 120 W or less. If the output of the linear beam after the beam size is adjusted exceeds 500 W, the cooling device for the light source of the semiconductor laser array may be enlarged.

  The image processing method may further include a scanning process, a control process, and the like. The image processing apparatus may further include a scanning unit, a control unit, and the like.

  The scanning step is a step of scanning a linear beam having a uniform light distribution in the length direction on the thermoreversible recording medium in a uniaxial direction, which is longer than the length of the light source of the semiconductor laser array, and is performed by the scanning unit. .

  The scanning unit is not particularly limited as long as it can scan a linear beam in a uniaxial direction, and examples thereof include a uniaxial galvanometer mirror, a polygon mirror, and a stepping motor mirror.

  The scanning speed of the line beam is usually 2 mm / s or more, preferably 10 mm / s or more, and more preferably 20 mm / s or more. If the scanning speed of the line beam is less than 2 mm / s, it may take time to erase the image. Further, the scanning speed of the line beam is usually 1000 mm / s or less, preferably 300 mm / s or less, and more preferably 100 mm / s or less. If the scanning speed of the line beam exceeds 1000 mm / s, it may be difficult to erase the image uniformly.

  In addition, by moving the thermoreversible recording medium to a linear beam that is longer than the length of the light source of the semiconductor laser array and has a uniform light distribution in the length direction, the linear beam is scanned to perform thermoreversible recording. It is preferable to erase the image recorded on the medium.

  Although it does not specifically limit as a moving part which moves a thermoreversible recording medium, A conveyor, a stage, etc. are mentioned.

  In this case, it is preferable that the thermoreversible recording medium is attached to the surface of the box and the thermoreversible recording medium is moved by moving the box by a conveyor.

  The control process is a process for controlling each process, and is performed by the control unit.

  The control unit is not particularly limited as long as the operation of each unit can be controlled, and examples include a sequencer and a computer.

  FIG. 4 shows an example of the image processing apparatus.

  The image processing apparatus has an oscillator unit including a laser oscillator 1, a beam expander 2, and a scanning unit 5.

  The laser oscillator 1 arranges mirrors on both sides of the laser medium, pumps the laser medium, increases the number of excited atoms, forms an inversion distribution, and stimulates emission. As a result, only the light in the optical axis direction is selectively amplified, so that the directivity of the light is increased and the laser light is emitted from the output mirror.

  The scanning unit 5 includes a galvanometer 4 and a mirror 4A attached to the galvanometer 4. The laser light output from the laser oscillator 1 is rotated and scanned by two mirrors 4A in the X-axis direction and the Y-axis direction attached to the galvanometer 4, thereby recording an image on the thermoreversible recording medium 100. Or erase.

  The image processing apparatus includes a power source control unit that includes a drive power source for a light source that excites a laser medium, a drive power source for a galvanometer, a cooling power source for a Peltier element, and a control unit that controls each unit.

  The image processing apparatus has a program unit for inputting and creating an image by inputting conditions such as laser light intensity and laser scanning speed in order to record or erase an image by touch panel input or keyboard input.

  The image processing apparatus further includes a transport unit that transports the thermoreversible recording medium 100, a touch panel, and the like.

  The recording medium is not particularly limited, and an irreversible recording medium and a thermoreversible recording medium can be used.

  In the thermoreversible recording medium, a thermoreversible recording layer is preferably formed on a support.

  Although it does not specifically limit as a shape of a support body, Flat shape etc. are mentioned.

  The structure of the support may be a single layer structure or a laminated structure.

  The material constituting the support is not particularly limited, but glass, quartz, silicon, silicon oxide, aluminum oxide, inorganic materials such as metal, paper, cellulose derivatives such as cellulose triacetate, synthetic paper, polyethylene terephthalate, polycarbonate, Organic materials such as polystyrene and polymethyl methacrylate may be mentioned, and two or more kinds may be used in combination. Among these, organic materials are preferable, polyethylene terephthalate, polycarbonate, and polymethyl methacrylate are more preferable, and polyethylene terephthalate is particularly preferable.

  The support is preferably surface-modified. Thereby, the adhesiveness of a coating layer can be improved.

  The surface modification treatment is not particularly limited, and examples thereof include corona discharge treatment, oxidation reaction treatment (for example, chromic acid treatment), etching treatment, easy adhesion treatment, and antistatic treatment.

  The support preferably contains a white pigment such as titanium oxide.

  The average thickness of the support is usually 10 μm to 2 mm, and preferably 50 μm to 1 mm.

  The support can be omitted.

  The thermoreversible recording layer contains a photothermal conversion material, a leuco dye, and a developer. At this time, it is possible to cope with multicolor and full color by laminating thermoreversible recording layers that develop colors of different colors.

  Photothermal conversion materials can be broadly classified into inorganic materials and organic materials.

  The inorganic material is not particularly limited, and examples thereof include metals or metalloids such as carbon black, Ge, Bi, In, Te, Se, and Cr, alloys containing metal or metalloid, metal borides, and metal oxides. .

  Examples of the metal boride and metal oxide include hexaboride, tungsten oxide, antimony-doped tin oxide (ATO), tin-doped indium oxide (ITO), and zinc antimonate.

  Although it does not specifically limit as an organic material, When using a semiconductor laser as a light source, the near-infrared absorption pigment | dye which has an absorption peak in a 700-1500 nm wavelength range is used.

  Examples of near infrared absorbing dyes include cyanine dyes, quinone dyes, quinoline derivatives of indonaphthol, phenylenediamine nickel complexes, phthalocyanine compounds, and the like, and two or more of them may be used in combination. Of these, phthalocyanine compounds are preferred because of their excellent heat resistance.

  A leuco dye and a developer are materials whose color tone can be reversibly changed by a temperature change, and depending on the difference in heating temperature and cooling rate after heating, the color developed and the color erased relatively. Can change.

  A leuco dye is a colorless or light-colored dye precursor.

  The leuco dye is not particularly limited. Examples thereof include methine series, rhodamine anilinolactam series, rhodamine lactam series, quinazoline series, diazaxanthene series, and bislactone series, and two or more kinds may be used in combination. Of these, fluoran-based or phthalide-based leuco dyes are preferred from the viewpoint of excellent color-developing properties, color, and storage stability.

  The developer is not particularly limited as long as it can reversibly develop and decolorize by using heat as a factor. However, the developer has a color developing ability to develop a leuco dye (for example, phenolic hydroxyl group, carboxyl group, And a compound having at least one structure (for example, a long-chain hydrocarbon group) that controls the cohesive force between phosphoric acid groups and molecules.

  The structure having a color developing ability to develop a leuco dye is preferably a phenolic hydroxyl group.

  The carbon number of the long chain hydrocarbon group is usually 8 or more and preferably 11 or more. Moreover, carbon number of a long chain hydrocarbon group is 40 or less normally, and it is preferable that it is 30 or less.

  In addition, the structure having a color developing ability for causing the leuco dye to develop and the structure for controlling the cohesive force between molecules may be linked via a divalent or higher valent linking group containing a hetero atom. Further, the long chain hydrocarbon group may be substituted with the same linking group and / or aromatic group.

  Developer is a general formula

（式中、Ｒ^１は、単結合又は炭素数が１〜２４の２価の脂肪族炭化水素基であり、Ｒ^２は、置換基を有していてもよい炭素数が２以上の２価の脂肪族炭化水素基であり、Ｒ^３は、炭素数が１〜３５の１価の脂肪族炭化水素基であり、Ｘ及びＹは、それぞれ独立に、Ｎ原子又はＯ原子を含む２価の基であり、ｎは０又は１である。）
で表される化合物であることが好ましく、一般式

(In the formula, R ¹ is a single bond or a divalent aliphatic hydrocarbon group having 1 to 24 carbon atoms, and R ² is a divalent having 2 or more carbon atoms which may have a substituent. R ³ is a monovalent aliphatic hydrocarbon group having 1 to 35 carbon atoms, and X and Y are each independently a divalent aliphatic group containing an N atom or an O atom. And n is 0 or 1.)
Is preferably a compound represented by the general formula

で表される化合物であることがさらに好ましい。

It is further more preferable that it is a compound represented by these.

R ² preferably has 5 or more carbon atoms, more preferably 10 or more.

R ³ preferably has 6 or more carbon atoms, more preferably 8 or more.

The sum of the carbon number of R ¹ , R ² and R ³ is usually 8 or more and preferably 11 or more. Moreover, the sum of the carbon numbers of R ¹ , R ² and R ³ is usually 40 or less, and preferably 35 or less. When the sum of the carbon numbers of R ¹ , R ² and R ³ is less than 8, the color development stability and decoloring property may be lowered.

  The aliphatic hydrocarbon group may be linear or branched, and may have an unsaturated bond, but is preferably linear.

  Although it does not specifically limit as a substituent, A hydroxyl group, a halogen atom, an alkoxy group, etc. are mentioned.

Although it does not specifically limit as bivalent group containing N atom or O atom, An oxygen atom, an amide bond (-NHCO-), a urea bond (-HNCONH-), Chemical formula -COHN-NHCO-
A group represented by the formula: -HNCO-CONH-
A group represented by the formula: -HNCONHCO-
The group etc. which are represented by these are mentioned. Of these, an amide bond and a urea bond are preferable.

  The developer is dispersed in the form of particles in the thermoreversible recording layer.

  The thermoreversible recording layer preferably further contains a decolorization accelerator.

As the decoloring accelerator, amide bond (—NHCO—) and / or chemical formula —OCONH—
If it has one or more groups represented by, it will not specifically limit.

  In the process of forming a decolored state, the decoloring accelerator induces an intermolecular interaction between the developers and can improve the color development / decoloring characteristics.

  The thermoreversible recording layer may further contain an additive in order to improve coating characteristics and color development / decoloring characteristics.

  Although it does not specifically limit as an additive, Surfactant, a electrically conductive agent, a filler, antioxidant, a light stabilizer, a coloring stabilizer, etc. are mentioned.

  The thermoreversible recording layer may further contain a binder resin.

  The binder resin is not particularly limited, but is preferably a thermosetting resin, an ultraviolet curable resin, or an electron beam curable resin in order to improve durability during repetition, and can be cross-linked by a cross-linking agent. Resins are particularly preferred.

  The thermosetting resin is not particularly limited, and is not particularly limited as long as it has a group capable of reacting with a crosslinking agent. However, phenoxy resin, polyvinyl butyral, cellulose acetate propionate, cellulose acetate butyrate. , Acrylic polyol, polyester polyol, polyurethane polyol and the like. Among these, acrylic polyol, polyester polyol, and polyurethane polyol are preferable.

  The hydroxyl value of the thermosetting resin is usually 50 to 400 mgKOH / g.

  The mass ratio of the binder resin to the leuco dye is usually 0.1 to 10. When the mass ratio of the binder resin to the leuco dye is less than 0.1, the thermal strength of the thermoreversible recording layer may be lowered, and when it exceeds 10, the color density may be lowered.

  Although it does not specifically limit as a crosslinking agent, Isocyanates, amino resin, a phenol resin, amines, an epoxy compound, etc. are mentioned. However, isocyanates are preferred, and polyisocyanates having a plurality of isocyanate groups are particularly preferred.

  The molar ratio of the active group of the crosslinking agent to the group capable of reacting with the crosslinking agent of the thermosetting resin is usually 0.01 to 2. When the molar ratio of the active group possessed by the crosslinking agent to the group capable of reacting with the crosslinking agent possessed by the thermosetting resin is less than 0.01, the thermal strength of the thermoreversible recording layer may be decreased. If it exceeds, the color development and decoloring characteristics may deteriorate.

  The crosslinking agent may be used in combination with a catalyst for the crosslinking reaction.

  The gel fraction of the thermoreversible recording layer is usually 30% or more, preferably 50% or more, and more preferably 70% or more. When the gel fraction of the thermoreversible recording layer is less than 30%, the durability of the thermoreversible recording medium may be lowered.

  A method for forming the thermoreversible recording layer is not particularly limited, but a coating solution in which a composition containing a binder resin, a photothermal conversion material, a leuco dye and a developer is dissolved or dispersed in a solvent is formed on a support. Examples thereof include a method of drying after coating, a method of molding a liquid obtained by heating and melting a composition containing a binder resin, a photothermal conversion material, a leuco dye, and a developer.

  Although it does not specifically limit as a solvent, Tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, chloroform, carbon tetrachloride, ethanol, toluene, benzene etc. are mentioned.

  The method for preparing the coating solution is not particularly limited, but a method for dissolving or dispersing the composition in a solvent, a method for dissolving or dispersing a material other than the binder resin after dissolving the binder resin in the solvent, and each material Are dissolved or dispersed in a solvent and then mixed, and the composition is heated and dissolved in a solvent and then cooled.

  The coating solution may further contain an antifoaming agent, a dispersing agent, a slip agent, a preservative, a crosslinking agent, a plasticizer and the like.

  The thermoreversible recording layer can be formed, for example, by applying a coating liquid while conveying a support continuously cut in a roll shape or in a sheet shape and then drying.

  The application method of the coating liquid is not particularly limited, but blade coating method, wire bar coating method, spray coating method, air knife coating method, bead coating method, curtain coating method, gravure coating method, kiss coating method, reverse roll coating method , Dip coating method, die coating method and the like.

  The conditions for drying the coating solution are usually about 25 seconds to 140 ° C. for 10 seconds to 10 minutes.

  The average thickness of the thermoreversible recording layer is usually 1 to 20 μm and preferably 3 to 15 μm. If the average thickness of the thermoreversible recording layer is less than 1 μm, the color density may decrease, and if it exceeds 20 μm, the color development temperature may not be reached and a portion that does not develop color may occur.

  A thermoreversible recording layer that does not include a photothermal conversion material may be formed, and a photothermal conversion layer that includes a photothermal conversion material may be formed on one or both sides of the thermoreversible recording layer.

  The photothermal conversion layer may further contain a binder resin.

  As the binder resin, either a thermoplastic resin or a thermosetting resin may be used, and the same resin as the binder resin of the thermoreversible recording layer can be used. Among these, in order to improve durability, a thermosetting resin, an ultraviolet curable resin, and an electron beam curable resin are preferable, and a thermosetting resin that can be cured by a crosslinking agent is preferable.

  The average thickness of the photothermal conversion layer is usually 0.1 to 20 μm.

  At this time, a barrier layer containing a binder resin may be formed between the thermoreversible recording layer and the photothermal conversion layer in order to prevent the two layers from interacting with each other.

  The thermoreversible recording medium may include an oxygen barrier layer, an ultraviolet absorbing layer, a back layer, a protective layer, an intermediate layer, an undercoat layer, an adhesive layer, an adhesive layer, a colored layer, an air layer, a light reflecting layer, and the like. Good.

  Each of these layers may have a single layer structure or a laminated structure.

  It is preferable to form oxygen barrier layers above and below the thermoreversible recording layer for the purpose of preventing photodegradation of the leuco dye in the thermoreversible recording layer by preventing oxygen from entering the thermoreversible recording layer. That is, it is preferable to form a first oxygen barrier layer between the support and the thermoreversible recording layer, and form a second oxygen barrier layer on the thermoreversible recording layer.

  Note that the first oxygen barrier layer may be formed on the side of the support on which the thermoreversible recording layer is not formed.

  The oxygen barrier layer is not particularly limited as long as it has a high visible light transmittance and a low oxygen permeability, but it is not limited to polyalkyl acrylate, polyalkyl methacrylate, polymethacrylonitrile, polyalkyl vinyl ester, Polyalkyl vinyl ether, polyfluorinated vinyl, polystyrene, vinyl acetate copolymer, cellulose acetate, polyvinyl alcohol, polyvinylidene chloride, acetonitrile copolymer, vinylidene chloride copolymer, poly (chlorotrifluoroethylene), ethylene -Resin film such as vinyl alcohol copolymer, polyacrylonitrile, acrylonitrile copolymer, polyethylene terephthalate, nylon-6, polyacetal, etc., resin film such as polyethylene terephthalate, nylon, silica, alumina, etc. Films such as inorganic oxide is deposited, and the like. Among these, a film in which an inorganic oxide is deposited on a resin film is preferable.

The oxygen permeability of the oxygen barrier layer is usually 20 mL / m ² / day / MPa or less, preferably 5 mL / m ² / day / MPa or less, and preferably 1 mL / m ² / day / MPa or less. Is more preferable. When the oxygen permeability of the oxygen barrier layer exceeds 20 mL / m ² / day / MPa, the leuco dye in the thermoreversible recording layer may be photodegraded.

  The oxygen permeability can be measured by a measuring method according to JIS K7126 B method.

  The method for forming the oxygen barrier layer is not particularly limited, and examples thereof include a melt extrusion method, a coating method, and a lamination method.

  The average thickness of the oxygen barrier layer is usually 0.1 to 100 μm. When the average thickness of the oxygen barrier layer is less than 0.1 μm, the leuco dye in the thermoreversible recording layer may be photodegraded, and when it exceeds 100 μm, the transparency of the oxygen barrier layer may be lowered.

  An adhesive layer may be formed between the oxygen barrier layer and the lower layer.

  Although it does not specifically limit as a formation method of an contact bonding layer, A coating method, a lamination method, etc. are mentioned.

  The average thickness of the adhesive layer is usually 0.1 to 5 μm.

  The adhesive layer may be crosslinked with a crosslinking agent.

  As the crosslinking agent, the same crosslinking agent as in the thermoreversible recording layer can be used.

  In the thermoreversible recording medium, a protective layer is preferably formed on the thermoreversible recording layer for the purpose of protecting the thermoreversible recording layer.

  The protective layer is preferably formed on the surface.

  The protective layer contains a binder resin and may further contain a release agent, a filler, and the like.

  The binder resin is not particularly limited, and examples thereof include a thermosetting resin, an ultraviolet curable resin, and an electron beam curable resin. Among these, an ultraviolet curable resin and a thermosetting resin are preferable.

  Use of UV curable resin can form a hard protective layer, and can prevent damage due to physical contact with the surface and deformation of the thermoreversible recording medium due to laser heating, thus improving durability. Can do.

  Further, when a thermosetting resin is used, the durability can be improved although it is slightly inferior to the case of using an ultraviolet curable resin.

  The UV curable resin is not particularly limited, but urethane acrylate, epoxy acrylate, polyester acrylate, polyether acrylate, vinyl, unsaturated polyester oligomer, monofunctional or polyfunctional acrylate, monofunctional or Monomers such as polyfunctional methacrylates, vinyl esters, ethylene derivatives, and allyl compounds are listed. Of these, tetrafunctional or higher polyfunctional monomers or oligomers are preferable.

  At this time, the hardness, shrinkage, flexibility, coating strength, etc. of the protective layer can be adjusted by using two or more ultraviolet curable resins in combination.

  In order to cure the ultraviolet curable resin, it is necessary to use a photopolymerization initiator and a photopolymerization accelerator.

  The mass ratio of the photopolymerization initiator or photopolymerization accelerator to the ultraviolet curable resin is usually 0.1 to 20%, and preferably 1 to 10%.

  A method of curing the ultraviolet curable resin is not particularly limited, and examples thereof include a method of irradiating ultraviolet rays using an ultraviolet irradiation device.

  The ultraviolet irradiation device includes a light source, a lamp, a power source, a cooling device, a transport device, and the like.

  Although it does not specifically limit as a light source, A mercury lamp, a metal halide lamp, a potassium lamp, a mercury xenon lamp, a flash lamp etc. are mentioned.

  As the thermosetting resin, the same resin as the thermosetting resin of the thermoreversible recording layer can be used.

  The thermosetting resin preferably has a group capable of reacting with a crosslinking agent such as a hydroxyl group, an amino group, or a carboxyl group, and more preferably has a hydroxyl group.

  As the crosslinking agent, the same crosslinking agent as that of the thermoreversible recording layer can be used.

  Examples of the release agent include a silicone resin having a polymerizable group, a resin grafted with a silicone resin, wax, zinc stearate, and silicone oil in order to improve transportability.

  The mass ratio of the release agent to the binder resin is usually 0.01 to 50%, preferably 0.1 to 40%.

  The filler is preferably a conductive filler, and more preferably a needle-like conductive filler.

  The protective layer may further contain a surfactant, a leveling agent, an antistatic agent and the like.

  As a method for forming the protective layer, a method similar to the method for forming the thermoreversible recording layer can be used.

  The average thickness of the protective layer is usually 0.1 to 20 μm, preferably 0.5 to 10 μm, and more preferably 1.5 to 6 μm. When the average thickness of the protective layer is less than 0.1 μm, the durability of the thermoreversible recording medium may be deteriorated, and when it exceeds 20 μm, the color development / decoloration characteristics of the thermoreversible recording medium may be deteriorated.

  For the purpose of preventing the leuco dye in the thermoreversible recording layer from being colored by ultraviolet rays and preventing disappearance due to photodegradation, an ultraviolet absorbing layer is preferably formed on the thermoreversible recording layer. Thereby, the light resistance of a thermoreversible recording medium can be improved.

  The ultraviolet absorbing layer contains a binder resin and an ultraviolet absorber, and may further contain a filler, a lubricant and the like.

  As the binder resin, either a thermoplastic resin or a thermosetting resin may be used, and the same resin as the binder resin of the thermoreversible recording layer can be used.

  The binder resin is not particularly limited, and examples thereof include polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate, and polyamide.

  As the ultraviolet absorber, either an organic compound or an inorganic compound may be used, but a polymer having an ultraviolet absorbing structure is preferably used.

  The ultraviolet absorbing structure is not particularly limited, and examples thereof include a salicylate structure, a cyanoacrylate structure, a benzotriazole structure, a benzophenone structure, etc. Among them, it can absorb ultraviolet rays having a wavelength of 340 to 400 nm, which is a cause of photodegradation of leuco dyes. Therefore, a benzotriazole structure and a benzophenone structure are preferable.

  The polymer having an ultraviolet absorbing structure preferably has a group capable of reacting with a crosslinking agent such as a hydroxyl group, an amino group, or a carboxyl group, and preferably has a hydroxyl group.

  The hydroxyl value of the polymer having an ultraviolet absorbing structure is usually 10 mgKOH / g or more, preferably 30 mgKOH / g or more, and more preferably 40 mgKOH / g or more. Thereby, the intensity | strength of an ultraviolet absorption layer can be improved, As a result, durability of a thermoreversible recording medium can be improved.

  The average thickness of the ultraviolet absorbing layer is usually from 0.1 to 30 μm, and preferably from 0.5 to 20 μm.

  As a method for forming the ultraviolet absorbing layer, a method similar to the method for forming the thermoreversible recording layer can be used.

  For the purpose of improving the adhesion between the thermoreversible recording layer and the protective layer, preventing alteration of the thermoreversible recording layer by applying the protective layer, and preventing the additives in the protective layer from being transferred to the thermoreversible recording layer, It is preferable that an intermediate layer is formed between the protective layers. Thereby, the preservation | save property of a color development image can be improved.

  The intermediate layer includes a binder resin and may further include a filler, a lubricant, and the like.

  As the binder resin, either a thermoplastic resin or a thermosetting resin may be used, and the same resin as the binder resin of the thermoreversible recording layer can be used.

  The binder resin is not particularly limited, and examples thereof include polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate, and polyamide.

  The intermediate layer preferably further contains an ultraviolet absorber.

  As an ultraviolet absorber, the same compound as the ultraviolet absorber of an ultraviolet absorption layer can be used.

  The average thickness of the intermediate layer is usually 0.1 to 20 μm, and preferably 0.5 to 5 μm.

  As a method for forming the intermediate layer, a method similar to the method for forming the thermoreversible recording layer can be used.

  For the purpose of improving sensitivity by effectively using the applied heat, improving the adhesion between the support and the thermoreversible recording layer, and preventing penetration of the recording layer material into the support. An under layer may be formed.

  The under layer includes hollow particles and may further include a binder resin or the like.

  Examples of the hollow particles include single hollow particles in which one hollow portion is present in the particle, multi-hollow particles in which many hollow portions are present in the particle, and the like, and two or more kinds may be used in combination.

  Although it does not specifically limit as a material which comprises a hollow particle, A thermoplastic resin etc. are mentioned.

  Examples of commercially available hollow particles include Microsphere R-300 (manufactured by Matsumoto Yushi Co., Ltd.), Ropaque HP1055, Ropaque HP433J (above, manufactured by Nippon Zeon Co., Ltd.), SX866 (manufactured by JSR Corporation), and the like.

  The content of the hollow particles in the under layer is usually 10 to 80% by mass.

  As the binder resin, either a thermoplastic resin or a thermosetting resin may be used, and the same resin as the binder resin of the thermoreversible recording layer can be used.

  The under layer may further contain a filler, a lubricant, a surfactant, a dispersant and the like.

  As the filler, either an inorganic filler or an organic filler may be used, but an inorganic filler is preferably used.

  The material constituting the inorganic filler is not particularly limited, and examples thereof include calcium carbonate, magnesium carbonate, titanium oxide, silicon oxide, aluminum hydroxide, kaolin, and talc.

  The average thickness of the under layer is usually 0.1 to 50 μm, preferably 2 to 30 μm, and more preferably 12 to 24 μm.

  A back layer may be formed on the side of the support on which the thermoreversible recording layer is not formed for the purpose of curling and preventing static charge of the thermoreversible recording medium and improving transportability.

  The back layer contains a binder resin and may further contain a filler, a lubricant, and the like.

  The binder resin is not particularly limited, and examples thereof include a thermosetting resin, an ultraviolet curable resin, and an electron beam curable resin. Among these, an ultraviolet curable resin and a thermosetting resin are preferable.

  As the binder resin, the same resin as the binder resin of the thermoreversible recording layer can be used.

  As the filler, the same filler as that of the protective layer can be used.

  A thermoreversible recording label may be formed by forming an adhesive layer on the side of the support on which the thermoreversible recording layer is not formed. Thereby, a thermoreversible recording label can be affixed to the entire surface or a part of a thick substrate such as a PVC card with a magnetic stripe which is difficult to form by applying a thermoreversible recording layer. As a result, a part of the information stored in the magnetism can be displayed, and convenience is improved. The thermoreversible recording label can also be applied to thick cards such as IC cards and optical cards.

  The material constituting the adhesive layer is not particularly limited, but urea resin, melamine resin, phenol resin, epoxy resin, vinyl acetate resin, vinyl acetate-acrylic copolymer, ethylene-vinyl acetate copolymer, acrylic Resin, polyvinyl ether resin, vinyl chloride-vinyl acetate copolymer, polystyrene resin, polyester resin, polyurethane resin, polyamide resin, chlorinated polyolefin resin, polyvinyl butyral resin, acrylate ester copolymer Examples thereof include a coalescence, a methacrylic ester copolymer, a natural rubber, a cyanoacrylate resin, and a silicone resin.

  The thermoreversible recording label may be a release paper type in which release paper is attached on the adhesive layer, or may be a non-release paper type in which release paper is not attached on the adhesive layer.

  For the purpose of improving visibility, a colored layer may be formed between the support and the thermoreversible recording layer.

  The colored layer contains a colorant and may further contain a binder resin.

  Although it does not specifically limit as a formation method of a colored layer, The method of drying after apply | coating the coating liquid in which the composition containing a coloring agent and binder resin is melt | dissolving or disperse | distributing in a solvent, A coloring agent and binder resin are included. The method etc. which stick a colored sheet are mentioned.

  Although it does not specifically limit as a coloring agent, The dye and pigment contained in the color ink used for full-color printing can be used.

  Although it does not specifically limit as binder resin, A thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, an electron beam curable resin etc. are mentioned.

  The thermoreversible recording medium may have a thermally irreversible recording layer. In this case, the color tone of the thermoreversible recording layer and the heat irreversible recording layer may be the same or different.

  Printing such as offset printing, gravure printing, or the like on part or the entire surface of the thermoreversible recording medium on which the thermoreversible recording layer is formed or on the part of the thermoreversible recording medium on which the thermoreversible recording layer is not formed The pattern may be formed by an inkjet printer, a thermal transfer printer, a sublimation printer, or the like. At this time, an OP varnish layer containing a curable resin may be further formed on a part or the entire surface of the pattern.

  Although it does not specifically limit as a pattern, A character, a pattern, a pattern, a photograph, the information etc. which can be detected with infrared rays etc. are mentioned.

  In addition, it can also color by adding dye and / or a pigment to either of each layer.

  A hologram can also be provided on the thermoreversible recording medium for security. In addition, in order to impart designability, the thermoreversible recording medium can be provided with a relief, an intaglio shape, and a design such as a person image, a company emblem, and a symbol mark.

  The shape of the thermoreversible recording medium is not particularly limited, and examples thereof include a card shape, a tag shape, a label shape, a sheet shape, and a roll shape.

  Examples of card-like thermoreversible recording media include prepaid cards, point cards, credit cards, and the like. A tag-like thermoreversible recording medium smaller than the card size includes a price tag. On the other hand, the tag-shaped thermoreversible recording medium larger than the card size includes a process management document, a shipping instruction document, a ticket and the like.

  The label-like thermoreversible recording medium is processed into various sizes and then attached to a cart, a container, a box, a container or the like, and can be used for process management, article management, and the like.

  Examples of the sheet-like thermoreversible recording medium include general documents and process management instructions.

  FIG. 5 shows a first example of the layer structure of the thermoreversible recording medium.

  In the thermoreversible recording medium 100A, a thermoreversible recording layer 102 containing a photothermal conversion material is formed on a support 101.

  A protective layer may be formed on the surface of the thermoreversible recording medium 100A on the side where the thermoreversible recording layer 102 is formed.

  FIG. 6 shows a second example of the layer structure of the thermoreversible recording medium.

  In the thermoreversible recording medium 100B, a thermoreversible recording layer 102A, a photothermal conversion layer 103, and a thermoreversible recording layer 102B are sequentially stacked on a support 101.

  A protective layer may be formed on the surface of the thermoreversible recording medium 100B on the side where the thermoreversible recording layers 102A and 102B are formed.

  FIG. 7 shows a third example of the layer structure of the thermoreversible recording medium.

  In the thermoreversible recording medium 100C, an oxygen barrier layer 104A, a thermoreversible recording layer 102 containing a photothermal conversion material, an oxygen barrier layer 104B, and an ultraviolet absorbing layer 105 are sequentially laminated on a support 101.

  A protective layer may be formed on the surface of the thermoreversible recording medium 100C on the side where the thermoreversible recording layer 102 is formed.

  FIG. 8 shows a fourth example of the layer structure of the thermoreversible recording medium.

  The thermoreversible recording medium 100D has the same configuration as the thermoreversible recording medium 100C except that the oxygen barrier layer 104A is formed on the side of the support 101 where the thermoreversible recording layer 102 is not formed.

  A protective layer may be formed on the surface of the thermoreversible recording medium 100D on the side where the thermoreversible recording layer 102 is formed.

  The thermoreversible recording medium integrates the information storage unit and displays a part of the information stored in the information storage unit on the reversible recording layer. It can be confirmed and is very convenient. In addition, when the contents of the information storage unit are rewritten, the thermoreversible recording medium can be repeatedly used by rewriting the display of the thermoreversible recording layer.

  The information storage unit is not particularly limited, and examples thereof include a magnetic recording layer, a magnetic stripe, an IC memory, an optical memory, and an RF-ID tag. When used for process management, article management, etc., an RF-ID tag is preferable. The RF-ID tag includes an IC chip and an antenna connected to the IC chip.

  The image processing method and the image processing apparatus can be applied to entrance / exit tickets, frozen food containers, industrial products, stickers for various chemical containers, screens for logistics management, manufacturing process management, etc. It is preferable to apply to a process management system in a factory.

  Examples of the present invention will be described below, but the present invention is not limited to the examples. In addition, a part means a mass part.

(Preparation of thermoreversible recording medium)
As a support, a white polyester film Tetron (registered trademark) film U2L98W (manufactured by Teijin DuPont Films Ltd.) having an average thickness of 125 μm was prepared.

  30 parts of a styrene-butadiene copolymer PA-9159 (manufactured by Nippon A & L), 12 parts of polyvinyl alcohol POVAL PVA103 (manufactured by Kuraray), 20 parts of hollow particle microsphere R-300 (manufactured by Matsumoto Yushi Co., Ltd.) and water 40 parts was stirred for 1 hour, and the coating liquid for underlayers was obtained.

  An under layer coating solution was applied onto the support using a wire bar, and then dried at 80 ° C. for 2 minutes to form an under layer having an average thickness of 20 μm.

  Chemical formula

で表される顕色剤５部、化学式

5 parts developer represented by the chemical formula

で表される消色促進剤０．５部、化学式

0.5 parts of the decolorization accelerator represented by the chemical formula

で表される消色促進剤０．５部、水酸基価が２００ｍｇＫＯＨ／ｇのアクリルポリオールの５０質量％溶液１０部及びメチルエチルケトン８０部を、ボールミルを用いて平均粒径が約１μｍになるまで分散させた。次に、ロイコ染料２−アニリノ−３−メチル−６−ジエチルアミノフルオラン１部、光熱変換材料ＬａＢ_６の１．８５質量％分散液ＫＨＦ−７Ａ（住友金属鉱山社製）４．８部及びイソシアネートのコロネートＨＬ（日本ポリウレタン社製）５部を加えた後、撹拌して、熱可逆記録層用塗布液を得た。

Disperse 0.5 parts of the decolorization accelerator represented by the formula, 10 parts of a 50% by weight acrylic polyol having a hydroxyl value of 200 mg KOH / g and 80 parts of methyl ethyl ketone until the average particle size is about 1 μm using a ball mill. It was. Next, 1 part of leuco dye 2-anilino-3-methyl-6-diethylaminofluorane, 4.8 parts of 1.85% by weight dispersion KHF-7A (manufactured by Sumitomo Metal Mining Co., Ltd.) of photothermal conversion material LaB ₆ and isocyanate After adding 5 parts of Coronate HL (manufactured by Nippon Polyurethane Co., Ltd.), the mixture was stirred to obtain a coating solution for a thermoreversible recording layer.

  After applying the thermoreversible recording layer coating solution on the under layer using a wire bar, the thermoreversible recording layer having an average thickness of 10 μm is dried at 100 ° C. for 2 minutes and crosslinked at 60 ° C. for 24 hours. Formed.

  A UV absorbent polymer coating solution was obtained by stirring 10 parts UV-G302 (manufactured by Nippon Shokubai Co., Ltd.) 10 parts, 1 part of an isocyanate coronate HL (manufactured by Nippon Polyurethane) and 12 parts of methyl ethyl ketone. .

  On the thermoreversible recording layer, an ultraviolet absorbing layer coating solution is applied using a wire bar, then dried at 90 ° C. for 1 minute, and crosslinked at 60 ° C. for 24 hours to form an ultraviolet absorbing layer having an average thickness of 10 μm. Formed.

  Pentaerythritol hexaacrylate KAYARAD DPHA (Nippon Kayaku Co., Ltd.) 3 parts, urethane acrylate oligomer art resin UN-3320HA (Negami Kogyo Co., Ltd.) 3 parts, dipentaerythritol caprolactone acrylate ester KAYARAD DPCA-120 (Japan) 3 parts of Kayaku Co., Ltd., 1 part of silica P-526 (manufactured by Mizusawa Chemical Co., Ltd.), 0.5 part of photopolymerization initiator Irgacure 184 (manufactured by Ciba Geigy Japan) and 11 parts of isopropyl alcohol were averaged using a ball mill. Dispersion was carried out until the particle size became about 3 μm to obtain a coating solution for protective layer.

  After applying the coating solution for the protective layer on the intermediate layer using a wire bar, it is dried at 90 ° C. for 1 minute, and irradiated with ultraviolet rays using an 80 W / cm ultraviolet lamp to crosslink, and the average thickness Formed a protective layer of 4 μm.

  Pentaerythritol hexaacrylate KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.) 7.5 parts, urethane acrylate oligomer art resin UN-3320HA (manufactured by Negami Kogyo Co., Ltd.) 2.5 parts, photopolymerization initiator Irgacure 184 (manufactured by Ciba Geigy Japan) 0.5 parts and 13 parts of isopropyl alcohol were stirred using a ball mill to obtain a coating solution for a back layer.

  On the surface of the support on which the thermoreversible recording layer is not formed, a back layer coating solution is applied using a wire bar, then dried at 90 ° C. for 1 minute, and irradiated with an 80 W / cm ultraviolet lamp. Then, a back layer having an average thickness of 4 μm was formed to obtain a thermoreversible recording medium.

Example 1
Using a rewritable laser marker LDM200-110 (manufactured by Ricoh), a laser having a center wavelength of 980 nm on a thermoreversible recording medium under conditions of an output of 15.9 W, an irradiation distance of 150 mm, a spot diameter of 0.48 mm, and a scanning speed of 4000 mm / s. The letter “8” having a height of 3.0 mm and a width of 3.0 mm was recorded by irradiation with light. At this time, the laser beam was irradiated so that the laser beam was not irradiated on the overlapping portion of the character “8”.

  Next, using a rewritable laser erasing machine LDE800-A (manufactured by Ricoh Company), the character “8” was recorded under the conditions of an output of 36 W, an irradiation distance of 110 mm, a short beam width of 1.1 mm, and a scanning speed of 45 mm / s. The thermoreversible recording medium was irradiated with laser light having a center wavelength of 976 nm to erase the character “8”.

(Example 2)
The character “8” was recorded and then erased in the same manner as in Example 1 except that the output was changed to 13.8 W.

(Example 3)
The character “8” was recorded and then erased in the same manner as in Example 1 except that the output was changed to 3.9 W, the character size was changed to 2.0 mm in height and 2.0 mm in width.

Example 4
After recording the character “8” in the same manner as in Example 1 except that the output was 19.1 W, the scanning speed was 6000 mm / s, the character size was changed to a height of 6.0 mm, and a width of 6.0 mm, Erased.

(Comparative Example 1)
The character “8” was recorded and then erased in the same manner as in Example 1 except that the output was changed to 19.1 W and the scanning speed was changed to 6000 mm / s.

(Comparative Example 2)
The character “8” was recorded and then erased in the same manner as in Example 1 except that the scanning speed was changed to 6000 mm / s.

(Comparative Example 3)
The character “8” was recorded and then erased in the same manner as in Example 2 except that the scanning speed was changed to 6000 mm / s.

(Comparative Example 4)
The character “8” was recorded and erased in the same manner as in Example 1 except that the output was changed to 19.1 W and the scanning speed was changed to 8000 mm / s.

(Comparative Example 5)
The character “8” was recorded and then erased in the same manner as in Example 1 except that the output was changed to 23.9 W and the scanning speed was changed to 6000 mm / s.

(Comparative Example 6)
The character “8” was recorded and then erased in the same manner as in Example 3 except that the output was changed to 13.8 W and the scanning speed was changed to 4000 mm / s.

(Comparative Example 7)
The character “8” was recorded and then erased in the same manner as in Example 1 except that the output was changed to 19.1 W and the scanning speed was changed to 1000 mm / s.

  Next, visibility and durability were evaluated.

[Visibility]
The visibility of the character “8” was evaluated visually. In addition, the case where distortion, crushing, or chipping was not seen in the character “8” was judged as “◯”, and the case where distortion, crushing, or chipping was seen in the character “8” was judged as “x”.

[durability]
Recording and erasing of the character “8” was repeated, and durability was evaluated. In addition, the case where the number of times that the uniform character “8” can be recorded and erased is less than 300 times is determined as “x”, the case where the number is 300 times or more and less than 1000 times is Δ, and the case where it is 1000 times or more is determined as “◯”. .

  Table 1 shows the evaluation results of visibility and durability.

表１から、実施例１〜４は、視認性及び耐久性に優れることがわかる。

From Table 1, it turns out that Examples 1-4 are excellent in visibility and durability.

  On the other hand, Comparative Examples 1 and 5 recorded the character “8” having an output of 19.1 to 23.9 W, a scanning speed of 6000 mm / s and a height of 3.0 mm and a width of 3.0 mm. Decreased.

  In Comparative Examples 2 to 4, since the character “8” having a height of 3.0 mm and a width of 3.0 mm was recorded at a scanning speed of 6000 to 8000 mm / s, the visibility was lowered.

  In Comparative Example 6, since the character “8” having an output of 13.8 W, a scanning speed of 4000 mm / s and a height of 2.0 mm and a width of 2.0 mm was recorded, visibility and durability were deteriorated.

  In Comparative Example 7, the character “8” having an output of 19.1 W, a scanning speed of 1000 mm / s, a height of 3.0 mm, and a width of 3.0 mm was recorded.

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Beam expander 3 Mask or aspherical lens 4 Galvanometer 4A Mirror 5 Scanning unit 6 f (theta) lens 100, 100A, 100B, 100C, 100D Thermoreversible recording medium 101 Support body 102, 102A, 102B Thermoreversible recording layer 103 Photothermal Conversion layer 104A, 104B Oxygen barrier layer 105 UV absorbing layer

JP 2012-35622 A

Claims (7)

Irradiating a recording medium with a laser beam to record an image including characters of different sizes ;
An image processing method comprising a step of controlling the scanning speed of the laser beam to decrease as the size of the predetermined character decreases. The image processing method according to claim 1, wherein a scanning speed of the laser beam when the height and / or width of the predetermined character is 3 mm is in a range of 4000 mm / s or more and less than 6000 mm / s .   The image processing method according to claim 1, wherein the character has a height and / or width of 5.0 mm or less.   4. The image processing according to claim 1, wherein when the character has an overlapping portion, the laser light is irradiated so as not to be irradiated with the laser light overlapping the overlapping portion. 5. Method.   The image processing method according to any one of claims 1 to 4, wherein the laser beam is irradiated using one or more selected from the group consisting of a YAG laser, a fiber laser, and a semiconductor laser.   6. The thermoreversible recording medium according to claim 1, wherein a thermoreversible recording layer including a photothermal conversion material, a leuco dye, and a developer is formed on a support. The image processing method according to one item. An image recording unit that irradiates a recording medium with laser light and records an image including characters of different sizes;
An image processing apparatus comprising: a control unit that performs control such that the scanning speed of the laser beam decreases as the size of the predetermined character decreases.

Images