JP4845556B2 - Non-contact type rewrite thermal label recording method - Google Patents

Description

  The present invention relates to a recording method for a non-contact type rewrite thermal label. More specifically, the present invention is a non-contact type rewrite thermal which can be repeatedly used more than 1000 times with little damage to the recording surface of the recording material even if information is recorded and erased repeatedly by a non-contact method. The present invention relates to a label recording method.

At present, heat-sensitive recording materials are the mainstream for labels used in the management of goods, such as labels on plastic containers that transport food, labels used in the management of electronic components, logistics management labels on cardboard, etc. . This heat-sensitive recording material is provided with a heat-sensitive recording layer mainly comprising an electron-donating usually colorless or light-colored dye precursor and an electron-accepting developer on a support. By heating with, for example, the dye precursor and the developer react instantaneously to obtain a recorded image. As such a heat-sensitive recording material, a rewritable label capable of forming an image, erasing the portion and recording again has become widespread. In this case, in order to rewrite the label attached to the adherend as it is, the information that has been recorded once is erased while the label is still attached to the adherend, and then the label is attached to a normal printer when recording again. It is necessary to pass through the kimono. In order to realize this, it is necessary to erase and write image information without contact.
Therefore, in order to repeatedly use labels in recent years, a reversible thermosensitive recording material capable of forming and erasing an image, for example, (1) an organic low-molecular substance whose reversibility changes reversibly depending on temperature on a support; A reversible thermosensitive recording material provided with a thermosensitive layer made of a resin, and (2) a reversible thermosensitive recording material provided with a thermosensitive coloring layer containing a dye precursor and a reversible developer on a support have been developed. Yes.
However, in the conventional non-contact type rewritable thermal label, damage is accumulated on the recording surface of the recording material by repeated use. Due to the damage of the recording surface, there is a disadvantage that the problem of reducing the number of repeated use occurs. Also, when recording an image that is a set of lines such as a solid image, when recording adjacent lines, when scanning and recording a laser beam continuously, the first recorded image part is decolored, There is a drawback that a problem that a clear image cannot be obtained occurs.
Specifically, in the conventional laser beam scanning method, the X-axis scanner and the Y-axis scanner are operated based on the coordinate data on the trajectory for each of the lines that make up a character or figure. There were the following problems. Since the X-axis scanner and the Y-axis scanner are stopped at the start (start point) and the end (end point) of drawing one line, acceleration and deceleration occur in the scanner of each axis near the start point and end point. Since the laser beam is irradiated at a constant output during this acceleration / deceleration period, more laser energy is irradiated in the vicinity of the start point and the end point than at the other locus points, and there is a problem that the deterioration of the base material is particularly noticeable. is there. In addition, when drawing a character by connecting the lines, the laser beam is irradiated again on the drawn line, so that the overlapped part is overlapped and the base material deteriorates. There is a point. Furthermore, when drawing a group of lines such as barcodes, the line of the barcode that was recorded first when drawing the next line due to the relationship between the time to draw the adjacent line and the temperature of the substrate due to laser beam irradiation. However, there is a problem that the color disappears and the density decreases. Here, the scanner is a scanning mirror.
JP 2003-118238 A JP 2002-215038 A JP 2003-320694 A JP 2003-320695 A JP 2004-90026 JP JP 2004-94510 A

  The present invention solves the problems of such a conventional non-contact type rewrite thermal label recording method, and damages to the recording surface of the recording material even if information is recorded and erased repeatedly by the non-contact method. The purpose of the present invention is to provide a recording method for a non-contact type rewritable thermal label, which can be used repeatedly 1000 times or more.

As a result of repeated earnest studies to achieve the above object, the present inventors used an optical scanning device, and when performing predetermined drawing by irradiating a laser beam focused on the non-contact type rewrite thermal label, The optical scanning device is continuously driven without oscillating the laser beam, and only when the virtual laser beam is moving at a substantially constant speed, the laser beam is oscillated to scan and draw the laser beam. The inventors have found that damage to the recording surface of the recording material can be reduced and the object can be achieved, and the present invention has been completed.
That is, the present invention
(1) A method of recording by irradiating a laser beam to a non-contact type rewrite thermal label, and using a light scanning device to irradiate the laser beam converged on the non-contact type rewrite thermal label to perform a predetermined drawing. In doing so, the optical scanning device is continuously driven without oscillating the laser beam, and the laser beam trajectory (virtual laser beam) assumed when the laser beam is oscillated moves at a constant speed for drawing. only when you are, the scanning of the laser beam by oscillating the laser beam to a method of drawing with a laser beam I line, when drawing a polyline, the predetermined line by scanning a laser beam with uniform motion And the scanning of the laser beam is interrupted when reaching the turning point, and the optical scanning device is continuously driven so that the virtual laser beam draws a loop starting from the turning point. From virtual laser beam past the turning point, the non-contact type rewrite thermal label method for the recording, characterized in that the laser beam is scanned so as to draw the next line by the scanning of uniform motion,
(2) When drawing, where the lines overlap, the point where the line overlaps is such that the virtual laser beam passes with the laser oscillator turned off, and the laser oscillator is turned on from the point of passage. The non-contact type rewrite thermal label recording method according to the above item (1), wherein the laser beam is scanned so as to draw the next line after passing the previously drawn line by drawing
( 3 ) The optical scanning device has a laser light source, a scanning mirror that can be rotated and driven to scan the laser light oscillated therefrom, and a focal length correction optical system that converges the laser light scanned by the scanning mirror, When performing predetermined drawing by irradiating the laser beam converged on the non-contact type rewrite thermal label, the scanning mirror is continuously driven and only when the scanning mirror is driven at a constant speed, the laser beam is emitted. The non-contact type rewrite thermal label recording method according to the above (1) or (2) , wherein the laser beam is oscillated and scanned and drawn.
( 4 ) In the optical scanning device, the scanning mirror capable of being driven to rotate is a galvano mirror, a polygon mirror, or a resonant mirror, and the non-contact type rewrite thermal label recording method described in ( 3 ) above, and ( 5 ) optical scanning. In the apparatus, the focal length correction optical system is an f-θ lens, and the recording method of the non-contact type rewrite thermal label according to ( 3 ) or ( 4 ),
Is to provide.

According to the present invention, there is provided a non-contact type rewrite thermal label that can be repeatedly used more than 1000 times with little damage to the recording surface of the recording material even when information is recorded and erased repeatedly by a non-contact method. A recording method can be provided.
In addition, when recording an image that is a set of lines such as a solid image, the first recorded image is clear so as not to cause decoloring or density reduction due to laser light scanned and irradiated to form an adjacent image. It is possible to provide a non-contact type rewritable thermal label recording method capable of obtaining an image.

The non-contact type rewrite thermal label recording method of the present invention is a recording method for performing predetermined drawing by irradiating the non-contact type rewrite thermal label with a laser beam using an optical scanning device. Only when the laser beam trajectory (virtual laser beam) is moving at a substantially constant speed when the device is continuously driven without oscillating the laser beam and the laser beam is oscillated. Oscillation is performed, laser light is scanned, and drawing is performed.
When drawing, it is preferable to scan the laser beam so that the part where the line overlaps passes the previously drawn line and then draws the next line. Scanning and drawing a predetermined line, the laser beam scanning is interrupted when reaching the turning point, and the optical scanning device is continuously driven so that the virtual laser beam draws a loop from the turning point. It is preferable that the laser beam is scanned so as to draw the next line after the virtual laser beam passes through the turning point.
In the present invention, “laser light oscillation” refers to an operation of turning on a laser light oscillator, which is a laser light generator, to generate laser light. “Laser light scanning” refers to scanning by driving an optical scanning device so that a laser beam irradiated to a predetermined position is obtained from the oscillated laser light. “Laser beam irradiation” means that the scanned laser beam is converged and irradiated to a non-contact type rewrite thermal label.
Although there is no restriction | limiting in particular as said optical scanning apparatus, For example, the focal length correction | amendment which converges the laser beam scanned with the scanning light source, the scanning mirror which can be driven to scan the laser beam oscillated from it, and the scanning mirror An apparatus having an optical system can be used.
As the laser light source in the optical scanning device, as will be described later, in the present invention, since a near-infrared laser beam having a wavelength in the range of 700 to 1500 nm is generally used, laser light having the wavelength can be oscillated. Any semiconductor laser (830 nm) and YAG laser (1064 nm) are preferably used.
Further, as a scanning mirror that can be driven to rotate for scanning the laser light emitted from the laser light source, a galvano mirror, a polygon mirror, a resonant mirror, or the like can be used. The galvanometer mirror is a type that controls a mirror with a magnet by an external magnetic field, and the polygon mirror is a type that rotates a polyhedral mirror. On the other hand, the resonant mirror has the same principle as the galvanometer mirror, but is of a type driven at a resonance frequency.

In the optical scanning device, examples of the focal length correction optical system for converging the laser light scanned by the scanning mirror include an optical system using an f-θ lens.
FIG. 1 is a schematic explanatory diagram of an example of an optical scanning device using a galvanometer mirror as a scanning mirror.
The laser light oscillated from the laser oscillator 11 passes through the lens 12 for increasing the spot diameter of the laser light, and is rotated by the motors 13a and 13b for the Y-axis scanning galvanometer mirror 14a and the X-axis scanning galvanometer mirror. The light is reflected by 14b and converged to a laser beam 16 having a predetermined diameter by a focal length correction optical system 15 using an f-θ lens or the like, and then irradiated to a non-contact type rewritable thermal label 17.
In the recording method of the present invention, for example, when performing predetermined drawing by irradiating a laser beam focused on a non-contact type rewrite thermal label using the optical scanning device, the galvano mirror is continuously driven and the galvano mirror is driven. Only when the mirror is driven at substantially constant speed, a method of performing scanning and drawing with laser light can be adopted.
Specifically, when drawing a character, the galvano mirror is driven with the laser oscillator turned off slightly before drawing the character, and when the virtual laser beam reaches the start point of the character, the galvano mirror is driven. The mirror is adjusted to be driven at substantially constant speed. When the virtual laser beam reaches the start point of the character, the laser oscillator is turned on to start drawing. During drawing, the galvanometer mirror is driven at substantially constant speed.
At the end of the character, the laser oscillator is turned off to stop drawing, but the galvanometer mirror is continuously driven and the drive speed or drive speed is changed so that the virtual laser beam reaches the start point of the next character. Adjust the drive of the galvanometer mirror.
By adopting such a method, in the conventional method, it can be avoided that excessive laser energy is irradiated in the vicinity of the start point and the end point of the character as described below.

In the conventional recording method, the driving of the X-axis scanning mirror and the Y-axis scanning mirror is stopped at the beginning (start point) and the end (end point) of drawing one line. Acceleration and deceleration occurs. Since the laser beam is irradiated at a constant output during this acceleration / deceleration period, more laser energy is irradiated in the vicinity of the start point and the end point than at the other locus points, and there is a problem that the deterioration of the base material is particularly noticeable. there were.
By adopting the recording method of the present invention, such a problem can be avoided.
In the recording method of the present invention, when drawing, it is desirable to scan the laser beam so that the portion where the line overlaps passes the previously drawn line and then draws the next line. In other words, when drawing a character by connecting the lines, the double overlap point is set so that the virtual laser is turned off so that it does not overlap the line once drawn when scanning over it again. The scanning mirror is driven so that the beam passes, and drawing is performed after turning on the laser oscillator. Thereby, the laser beam irradiation is not performed on the overlapping part of the line, and the deterioration of the substrate can be suppressed.
In the conventional recording method, when drawing a character by connecting the lines, the laser beam is irradiated again on the drawn line once, so the overlapped part is overlapped and the base material deteriorates. However, by adopting the above recording method, such a problem can be avoided.

Further, in the recording method of the present invention, when drawing the broken line, the laser beam is scanned to draw a predetermined line, and when the turn-around point is reached, the scanning of the laser beam is interrupted, and the scanning mirror It is desirable that the laser beam is continuously driven so as to draw a loop starting from the turning point, and the laser beam is scanned so as to draw the next line after the virtual laser beam passes the turning point. Thereby, excessive laser energy irradiation at an acute turning point can be avoided.
Also, when drawing a character, instead of drawing the next character immediately after scanning the laser beam once, the next image is created by providing a part that drives the scanning mirror with the laser oscillator turned off. It is desirable to provide time until drawing. As a result, it is possible to prevent erasure of adjacent images and density reduction.
In the conventional recording method, when drawing a collection of lines such as barcodes, the recording was first performed when drawing the adjacent line due to the relationship between the time to draw the adjacent line and the temperature of the substrate by laser beam irradiation. Although there has been a problem that the bar code line is decolored and the density is lowered, such a problem can be avoided by adopting the above recording method.
Next, in order to deepen the understanding of the recording method of the present invention, the difference between the printing method by the recording method of the present invention and the printing method by the conventional recording method is shown in FIG. .
FIG. 2 is an explanatory diagram showing the difference between the printing method according to the recording method of the present invention and the printing method according to the conventional recording method when the character A is printed, and the left side portion shows the printing method according to the method of the present invention. The right side shows the printing method according to the conventional method.
The printing method according to the method of the present invention and the printing method according to the conventional method will be described with reference to FIG.
First, a printing method ((1) in FIG. 2) according to the method of the present invention will be described.
In the printing method according to the method of the present invention, first, (a) scanning of the galvano mirror is started and moved until the virtual laser beam reaches the character start point. (B) The laser beam oscillation is turned on at the character start point, and a line is drawn by irradiating the laser beam. (C) When the apex of the letter A is reached (character folding point), the laser light oscillation is turned off and the galvano mirror is scanned so that the virtual laser beam draws a loop indicated by a dotted line. (D) When the end point drawn in the above (b) is exceeded, the laser beam oscillation is turned on, the laser beam is irradiated, and the next line is drawn without overlapping the previously drawn line.
(E) When reaching the end point of the line drawn in (d) (the lower right end of the letter A, the character folding point), the oscillation of the laser beam is turned off and the virtual laser beam shows a dotted line Scan the galvanometer mirror. (F) When the virtual laser beam exceeds the line drawn in (d), the laser beam oscillation is turned on, the laser beam is irradiated, a line is drawn, and the line (A) drawn in (b) (A) The laser beam oscillation is turned off just before reaching the left line of the character. (G) Scan the galvanometer mirror so that the virtual laser beam shows a dotted line. In this way, the A character is printed.
Thereafter, the galvano mirror remains in the ON state, and scanning is performed so that the virtual laser beam reaches the next character at a high speed.
Next, a conventional printing method ((2) in FIG. 2) will be described.
In the conventional printing method, first, (a1) the galvanometer mirror is scanned, and when the virtual laser beam reaches the character start point, scanning of the galvanometer mirror is stopped and the apparatus is put on standby for a moment. (A) While scanning the galvanometer mirror, the laser beam oscillation is turned on and a laser beam is irradiated to draw a line. (A2) When the vertex of the letter A is reached, the scanning of the galvano mirror is stopped and the laser light oscillation is turned off simultaneously. (B1) The galvanometer mirror is scanned, and when the virtual laser beam reaches the start point of the next character, the galvanometer mirror is stopped and waited for a moment.
(B) While scanning the galvanometer mirror, the laser beam oscillation is turned on and the laser beam is irradiated, and the next line is drawn overlapping the previously drawn line. (B2) When the end point of the line drawn in (b) (the lower right end of the letter A) is reached, the scanning of the galvano mirror is stopped and the laser light oscillation is turned off simultaneously. (C1) The galvanometer mirror is scanned, and when the virtual laser beam reaches the start point of the next character, the galvanometer mirror is stopped and waited for a moment. (C) The galvanometer mirror is scanned, the laser beam oscillation is turned on and the laser beam is irradiated, and the next line is drawn by overlapping the previously drawn line. (C2) When the end point of the line drawn in (c) is reached, scanning of the galvanometer mirror is stopped and laser light oscillation is turned off simultaneously. In this way, the A character is printed.

The laser beam used in the present invention is preferably irradiated with a near-infrared laser beam having a wavelength in the range of 700 to 1500 nm. Those having a wavelength shorter than 700 nm are not preferable because the visibility and the readability of the optical reflection reading symbol are lowered. A wavelength longer than 1500 nm is not preferable because the energy per pulse unit is high and the influence of heat is large, so that the light-absorbing heat conversion layer is gradually destroyed and the durability of repeated recording and erasing is reduced.
As the recording method of the present invention, a recording method is used in which the scanning mirror is continuously driven as described above, and scanning is performed with laser light only when the scanning mirror is driven at substantially constant speed.
In the method of the present invention, the distance between the surface of the rewrite thermal label and the laser light source at the time of recording varies depending on the scanning speed and the irradiation output, but it is possible to prevent deterioration of the substrate, character density (barcode readability), character size. It is necessary to select in consideration of this. Preferably, the laser output is 3.0 to 3.6 W, the irradiation distance is 200 to 210 mm, and the duty is 65 to 75% during recording, and the laser output is 8 W, the irradiation distance is 420 to 425 mm, and the duty is 100% when erasing. The scan speed is preferably increased within a range that does not impair printing performance or erasing performance.

A good image can be obtained by irradiating with a recording laser beam and then rapidly cooling with a cooling air or the like. In this cooling operation, scanning with laser light and rapid cooling with cooling air may be performed alternately or simultaneously.
The recorded image erasing method in the method of the present invention is performed to rewrite the information on the rewrite thermal label into new information. In this case, first, the recorded label surface is irradiated with a near infrared laser beam of 700 to 1500 nm. In addition to the laser beam irradiation with a predetermined energy amount, the image remaining rate can be further reduced by further reducing the cooling rate by a method of contacting a hot roll or the like or a method of blowing hot air.
If the heating roll can heat the label surface to about 100-140 ° C. within 4 seconds from the start of laser beam irradiation when erasing the record, and does not damage the label surface, A known heating roll can be used without particular limitation. For example, a rubber roll, a stainless steel roll, etc. can be used. In particular, a silicone rubber roll having excellent heat resistance can be suitably used. The rubber hardness is preferably 40 degrees or more. When it becomes a soft rubber roll of less than 40 degrees, for example, the adhesive force to the light absorption heat conversion layer becomes strong, and there is a possibility that problems such as the light absorption heat conversion layer being taken by the rubber roll may occur.
Further, the recorded image can be erased by blowing hot air. In this case, hot air of about 80 to 140 ° C. is blown for about 10 to 60 seconds.
In the rewriting method according to the present invention, when image recording is performed again after erasing the image, the recording is performed in the same manner as the first recording. In particular, in this case, even if the rewritable thermal label is still attached to the adherend, the rewriting can be realized by irradiating the laser beam in a non-contact state.
The non-contact type rewritable thermal label to which the recording method of the present invention is applied is not particularly limited, and an arbitrary one can be appropriately selected from conventionally known ones. For example, JP-A-2003-118238 Can be used. Labels that can rewrite (rewrite) by reversibly recording (writing / printing) and erasing in a non-contact manner by coloring or decoloring the reversible thermosensitive coloring layer by heat generated in the light-absorbing / heat-conversion layer usually by optical stimulation Used.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Production Example 1 Preparation of Coating Liquid (Liquid A) for Formation of Thermosensitive Coloring Layer As a dye precursor, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2) which is a triarylmethane compound -Methylindol-3-yl) -4-azaphthalide 100 parts by weight, 30 parts by weight of 4- (N-methyl-N-octadecylsulfonylamino) phenol as reversible developer, 1.5 parts by weight of polyvinyl acetal as a dispersant Then, 2500 parts by weight of tetrahydrofuran as a diluting solvent was pulverized and dispersed by a pulverizer and a disper to prepare a coating solution for forming a thermosensitive color developing layer (liquid A).
Production Example 2 Preparation of coating liquid for forming light absorption heat conversion layer (liquid B) Near infrared light absorption heat conversion agent (nickel complex dye) [trade name “SDA-5131” manufactured by Tosco Co., Ltd.] Parts by weight, ultraviolet curable binder (urethane acrylate) [manufactured by Dainichi Seika Kogyo Co., Ltd., trade name “PU-5 (NS)”] and inorganic pigment (silica) [manufactured by Nippon Aerosil Kogyo Co., Ltd., A product name “Aerosil R-972”] 3 parts by weight was dispersed with a disper to prepare a coating liquid for forming a light absorption heat conversion layer (liquid B).
Production Example 3 Production of Adhesive Layer with Release Sheet Silicone resin [Toray Dow Corning Co., Ltd.] with a catalyst added on a 100 μm thick polyethylene terephthalate film [trade name “Lumirror T-60” manufactured by Toray Industries, Inc.] ) And a trade name “SRX-211”] were prepared so that the thickness after drying was 0.7 μm.
On the silicone resin layer of the release sheet, 100 parts by weight of an acrylic pressure-sensitive adhesive [manufactured by Toyo Ink Mfg. Co., Ltd., trade name “Olivein BPS-1109”] and a crosslinking agent [manufactured by Nippon Polyurethane Industry Co., Ltd., trade name] The pressure-sensitive adhesive coating solution to which 3 parts by weight of “Coronate L”] was added was applied by a roll knife coater method so that the thickness after drying was 30 μm. This pressure-sensitive adhesive-coated film was dried in an oven at a temperature of 100 ° C. for 2 minutes to produce a pressure-sensitive adhesive layer with a release sheet.

Example 1
(1) Preparation of sample for recording On the foamed polyethylene terephthalate film [Toyobo Co., Ltd., a brand name "Crisper K2424"] of thickness 100micrometer as a base material, the A liquid prepared by the manufacture example 1 was gravure-type. It was applied so that the thickness after drying was 4 μm, and dried in an oven at 60 ° C. for 5 minutes to form a thermosensitive coloring layer. Next, the liquid B prepared in Production Example 2 was applied on the thermosensitive coloring layer by a flexo method so that the thickness after drying was 1.2 μm, and dried in an oven at 60 ° C. for 1 minute. The light-absorbing heat conversion layer was produced by irradiating ultraviolet rays at a light amount of 220 mJ / cm ² to obtain a substrate for rewritable thermal labels.
The pressure-sensitive adhesive layer with a release sheet produced in Production Example 3 was laminated with a surface on which the heat-sensitive color-developing layer and the light-absorbing heat conversion layer of the rewritable thermal label substrate were not formed using a laminator.
(2) Recording / Erasing (a) The number “4” is applied to the recording sample obtained in (1) above by the following recording (printing) method, and the laser beam scanning method shown in FIG. ) Was recorded.
<Recording (printing) method>
Recording was performed using a YAG laser (wavelength: 1064 nm) [trade name “LP-F10W” manufactured by Sunkus Co., Ltd.] as a laser marker for irradiation with a laser beam.
The irradiation distance was 210 mm, the laser output was 3.3 W, the duty was 70%, the scan speed was 3000 mm / second, the pulse period was 100 μs, the line width was 0.1 mm, and the fill interval was adjusted to 0.05 mm.
In FIG. 3, first, the scanning mirror starts to be driven at point A, and when the virtual laser beam reaches the character start point a, the laser oscillator is turned on to start drawing, and a line b is drawn. At the character folding point c, the laser oscillator is turned off and the scanning mirror is driven so that the virtual laser beam draws a loop indicated by a dotted line. When the virtual laser beam reaches the point c ′, the laser oscillator is driven. Turn on and start drawing again to draw line d.
Next, at the turning point e of the character, the laser oscillator is turned off and the scanning mirror is driven so that the virtual laser beam draws a loop indicated by a dotted line, and when the virtual laser beam reaches the point e ′. The laser oscillator is turned on and drawing is started again to draw a line f. At the point g, the laser oscillator is turned off. When the virtual laser beam reaches the point g ′, the laser oscillator is turned on and drawing is started again to draw a line h. At the point i, which is the end point of the character, the laser oscillator is turned off to finish drawing.
The scanning mirror stops driving when the virtual laser beam draws a dotted line and reaches point B. In this way, the number “4” is recorded.
When the laser oscillator is on, the scanning mirror is in a substantially constant speed drive state.
Next, the characters thus recorded were erased by the following erase method.
<Erase method>
After hot air of 130 ° C. was blown for 20 seconds, the print was erased by naturally cooling in a room temperature environment.
(B) A barcode was recorded on the recording sample obtained in (1) above according to the laser beam scanning method of the present invention.
The thick line of the bar code is a set of lines, and the recording method of each line will be described with reference to FIG.
<Recording (printing) method>
Recording was performed using a YAG laser (wavelength: 1064 nm) [trade name “LP-F10W” manufactured by Sunkus Co., Ltd.] as a laser marker for irradiation with a laser beam.
The irradiation distance was 210 mm, the laser output was 3.3 W, the duty was 70%, the scan speed was 3000 mm / second, the pulse period was 100 μs, the line width was 0.1 mm, and the fill interval was adjusted to 0.05 mm.
In FIG. 4, first, the scanning mirror starts to be driven at point A, and when the virtual laser beam reaches the start point a, the laser oscillator is turned on to start drawing, and a line b is drawn. At the point c, the laser oscillator is turned off, and the scanning mirror is driven so that the virtual laser beam draws a loop indicated by a dotted line. When the virtual laser beam reaches the point d, the laser oscillator is turned on. Drawing is started again and a line e is drawn.
Next, at the point f, the laser oscillator is turned off and the scanning mirror is driven so that the virtual laser beam draws a loop indicated by a dotted line. When the virtual laser beam reaches the point g, the laser oscillator is turned on. Then, drawing is started again and a line h is drawn. The laser oscillator is turned off at point i and the scanning mirror is driven so that the virtual laser beam draws a loop indicated by a dotted line. When the virtual laser beam reaches point j, the laser oscillator is turned on and turned on again. Start drawing and draw line k. At the point m which is the end point of the character, the laser oscillator is turned off and drawing is finished.
The scanning mirror stops driving when the virtual laser beam draws a dotted line and reaches point B. In this way, a barcode is recorded.
When the laser oscillator is on, the scanning mirror is in a substantially constant speed drive state.
According to such a recording method, when the adjacent line was drawn, the first recorded barcode line did not cause decolorization or density reduction.
<Erase method>
Erasing was performed in the same manner as in (a) above.
(3) Evaluation The recording and erasure of (2) (a) above are repeated 50 times, 500 times and 1000 times, the character start point a, end point i, and overlapping portions cc ′, ee ′, g The state of the substrate surface at −g ′ was observed. Further, the bar code readability after repeating the recording and erasing of (2) and (b) 500 times and 1000 times was evaluated. The results are shown in Table 1.

Example 2
(1) Production of sample for recording On a foamed polyethylene terephthalate film [Toyobo Co., Ltd., trade name “Crisper K2424”] having a thickness of 100 μm as a base material, 2631.5 parts by weight of A solution prepared in Production Example 1 And 104 parts by weight of the B solution prepared in Production Example 2 are mixed, applied and dried by a flexo method so that the thickness after drying becomes 5.0 μm, and irradiated with ultraviolet rays to form a heat-sensitive color former and light absorption heat. A thermosensitive coloring layer composed of a conversion agent mixed layer was prepared and used as a rewritable thermal label substrate.
Thereafter, recording samples were produced in the same manner as in Example 1 (1).
(2) Recording / Erasing In the same manner as in Example 1 (2), the number “4” or barcode was recorded on the recording sample obtained in (1) above, and further erased.
(3) Evaluation Recording and erasure of the number “4” in (2) above was repeated 50 times, 500 times and 1000 times, and bar code recording and erasure were repeated 500 times and 1000 times, and then Example 1 (3 ) And the same evaluation. The results are shown in Table 1.

Comparative Example 1
(1) Production of recording sample A recording sample was produced in the same manner as in Example 1 (1).
(2) Recording / Erasing (a) The number “4” was recorded on the recording sample obtained in the above (1) by the following recording (printing) method according to the laser beam scanning method shown in FIG. .
<Recording (printing) method>
Recording was performed using a YAG laser (wavelength: 1064 nm) [trade name “LP-F10” manufactured by Sunkus Co., Ltd.] as a laser marker for irradiating a laser beam.
Irradiation conditions are an irradiation distance of 180 mm, a laser output of 2.0 W, a scanning speed of 1000 mm / s, a pulse period of 100 μs, a line width of 0.1 mm, and a filling interval of 0.05 mm.
In FIG. 4, first, the scanning mirror is driven. When the virtual laser beam reaches the character start point p, the scanning mirror is stopped. After waiting for a moment, the scanning mirror is driven and the laser oscillator is turned on. Starts drawing and draws a line q. When the point r is reached, the driving of the scanning mirror is stopped and the laser oscillator is turned off simultaneously.
Next, at a point r, after waiting for a moment, the scanning mirror is driven, the laser oscillator is turned on, drawing is started, and a line s is drawn. When the point t is reached, the driving of the scanning mirror is stopped and the laser oscillator is turned off simultaneously.
Next, at the point t, after waiting for a moment, the scanning mirror is driven, the laser oscillator is turned on, drawing is started, and a line u is drawn. When the line u crosses the previously drawn line q at the point v and then reaches the end point w of the character, the scanning mirror is stopped and the laser oscillator is turned off simultaneously. In this way, the number “4” is recorded.
Next, the characters thus recorded were erased by the following erase method.
<Erase method>
After hot air of 130 ° C. was blown for 20 seconds, the print was erased by naturally cooling in a room temperature environment.
(B) Bar codes were recorded on the recording sample obtained in (1) above by the following recording (printing) method. The thick line of the barcode is a set of lines, and the recording method of each line will be described with reference to FIG.
<Recording (printing) method>
Recording was performed using a YAG laser (wavelength: 1064 nm) [trade name “LP-F10” manufactured by Sunkus Co., Ltd.] as a laser marker for irradiation with a laser beam.
The irradiation conditions are an irradiation distance of 180 mm, a laser output of 2.0 W, a scan speed of 1000 mm / s, a pulse period of 100 μs, a line width of 0.1 mm, and a fill interval of 0.05 mm.
In FIG. 6, first, the scanning mirror is driven, and when the virtual laser beam reaches the starting point n of the line, the scanning mirror is stopped. After waiting for a moment, the scanning mirror is driven and the laser oscillator is turned on. Then, drawing is started and a line o is drawn. When the laser beam reaches the point p, the driving of the scanning mirror is stopped and the laser oscillator is turned off simultaneously.
Next, the scanning mirror is driven so that the virtual laser beam draws a dotted line, and when the virtual laser beam reaches the point q, the scanning mirror is stopped, and after waiting for a moment, the scanning mirror is driven. Drawing is started by turning on the laser oscillator, and a line r is drawn. When the laser beam reaches point s, the driving of the scanning mirror is stopped and the laser oscillator is turned off simultaneously.
Next, the scanning mirror is driven so that the virtual laser beam draws a dotted line, and when the virtual laser beam reaches the point t, the scanning mirror driving is stopped, and after waiting for a moment, the scanning mirror is driven, Drawing is started by turning on the laser oscillator, and a line u is drawn. When the laser beam reaches point v, the scanning mirror is stopped and the laser oscillator is turned off simultaneously.
Next, the scanning mirror is driven so that the virtual laser beam draws a dotted line, and when the virtual laser beam reaches the point w, the scanning mirror is stopped, and after waiting for a moment, the scanning mirror is driven. Drawing is started by turning on the laser oscillator, and a line x is drawn. When the laser beam reaches the point y, the scanning mirror is stopped and the laser oscillator is turned off simultaneously.
In this way, a barcode is recorded.
<Erase method>
Erasing was performed in the same manner as in (a) above.
(3) Evaluation The recording and erasure in (2) (A) above are repeated 50 times, 500 times and 1000 times, and the state of the substrate surface at the start point p and end point w of characters and r, t and v of overlapping portions. Was observed. Further, the bar code readability after repeating the recording and erasing of (2) and (b) above 500 times was evaluated. The results are shown in Table 1.

Comparative Example 2
(1) Production of recording sample A recording sample was produced in the same manner as in Example 2 (1).
(2) Recording / Erasing The recording sample obtained in the above (1) was recorded with the numeral “4” or a barcode in the same manner as in Comparative Example 1 (2), and further erased.
(3) Evaluation After repeating the recording and erasure of the number “4” in the above (2) 50 times, 500 times and 1000 times, and repeating the recording and erasing of the barcode 500 times, the same as in Comparative Example 1 (3) Was evaluated. The results are shown in Table 1.

(note)
(1) State of substrate surface ○: No substrate destruction ×: Substrate destruction (2) Bar code readability Bar code readability after 500 times and 1000 times rewriting was evaluated according to the following method.
A hand-held bar code verifier (manufactured by Izumi Data Logic Co., Ltd., “RJS Inspector 3000”) that emits laser light having a wavelength of 660 nm is scanned by moving back and forth on the one-dimensional bar code symbol. Scan 10 times, and use the average as the evaluation result. The bar code symbol print quality is determined by scanning the bar and space reflectivity, the presence or absence of voids or spots, and the dimensional accuracy of the elements. Readability based on ANSI (American National Standards Institute) From A with good quality, it is positioned as A, B, C, and D, and F that cannot be read at all is F.
○: ANSI evaluation A to D
×: ANSI evaluation F
In addition, the above-mentioned bar means a black line, space means a white blank portion between bars, void means a small defect (white gap) in the bar, and spot means a larger defect in the black line. The reflectance between the bar and the space is determined by the difference in reflectance between the bar and the blank portion, and the presence or absence of voids or spots is determined based on the presence of these.
As can be seen from Table 1, according to the recording method of the present invention, the heat-sensitive color forming layer and the light-absorbing heat converting layer are laminated (Example 1), and the case of a single layer of the heat-sensitive coloring layer containing the light absorbing heat converting agent. In any of (Example 2), 500 times of recording and erasing are possible, and there is no destruction of the substrate surface after 500 times of recording and erasing, and re-recording is possible. Also, barcode reading is good. The state of the substrate surface after 1000 rewrites was almost the same as the state of the substrate surface after 500 rewrites.
On the other hand, according to the conventional recording method, a heat-sensitive color-developing layer and a light-absorbing heat-converting layer are laminated (Comparative Example 1) and a heat-sensitive color-forming layer containing a light-absorbing heat-converting agent is a single layer (Comparative Example 2). In either case, recording and erasing were possible 50 times, but the recording and erasing were performed 500 times and 1000 times, the surface of the substrate was broken, and the barcode readability was poor.

According to the recording method of the non-contact type rewrite thermal label of the present invention, even if information is repeatedly recorded and erased by the non-contact method, there is little damage to the recording surface of the recording material and it can be used repeatedly 1000 times or more. It is.
The recording method of the present invention can be applied to, for example, a label attached to a plastic container (return box) for transporting food, a label used for managing electronic components, a logistics management label attached to cardboard, and the like.

It is a schematic explanatory drawing of an example of the optical scanning device used in the recording method of the non-contact-type rewrite thermal label of this invention. It is explanatory drawing which shows the difference of the printing method by the recording system of this invention, and the printing method by the conventional recording system. It is explanatory drawing which shows the scanning system of a laser beam in the character drawing in an Example. It is explanatory drawing which shows the scanning system of a laser beam in the barcode drawing in an Example. It is explanatory drawing which shows the scanning system of a laser beam in the character drawing in a comparative example. It is explanatory drawing which shows the scanning system of a laser beam in the barcode drawing in a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Laser oscillator 12 Lens for enlarging the spot diameter of laser light 13a, 13b Motor 14a Y-axis scanning galvano mirror 14b X-axis scanning galvano mirror 15 Focal length correction optical system 16 Laser beam 17 Non-contact type rewrite thermal label

Claims (5)

A method of irradiating and recording a laser beam on a non-contact type rewritable thermal label, using an optical scanning device, and irradiating a laser beam converged on the non-contact type rewritable thermal label, Only when the optical scanning device is continuously driven without oscillating the laser beam and the locus of the laser beam (virtual laser beam) assumed when the laser beam is oscillated is moving at a constant speed for drawing. to a method of by oscillating the laser beam to draw the laser beam scanning of the laser beam I line, when drawing a polygonal line scans the laser beam in uniform motion to draw a predetermined linear When the turning point is reached, the scanning of the laser beam is interrupted, and the optical scanning device is continuously driven so that the virtual laser beam draws a loop from the turning point and the virtual laser beam is drawn. Zabimu from the past the turning point, the non-contact type rewrite thermal label method for the recording, characterized in that the laser beam is scanned so as to draw the next line by the scanning of the uniform motion.   When drawing, where the lines overlap, the point where the line overlaps is drawn with the laser oscillator turned off so that the virtual laser beam passes and the laser oscillator is turned on from the point of passage. 2. The non-contact type rewrite thermal label recording method according to claim 1, wherein the laser beam is scanned so as to draw the next line after passing through the previously drawn line. The optical scanning device has a laser light source, a scanning mirror that can be rotated to scan the laser light emitted from the laser light source, and a focal length correction optical system that converges the laser light scanned by the scanning mirror, and the non-contact method When performing predetermined drawing by irradiating the laser beam focused on the mold rewrite thermal label, the scanning mirror is continuously driven, and the laser beam is oscillated only when the scanning mirror is driven at a constant speed. non-contact type rewrite thermal label method for the recording according to claim 1 or 2 draws perform scanning of the laser beam. 4. The non-contact type rewrite thermal label recording method according to claim 3 , wherein in the optical scanning device, the scanning mirror that can be rotationally driven is a galvanometer mirror, a polygon mirror, or a resonant mirror. In the optical scanning apparatus, the focal distance correction optical system, the non-contact type rewrite thermal label method for the recording according to claim 3 or 4 which is a f-theta lens.

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