JP7435088B2 - Laser recording device, laser recording method, and laser irradiation program for laser recording - Google Patents

Description

The present invention relates to a laser recording device, a laser recording method, and a laser irradiation program for laser recording.

BACKGROUND ART Conventionally, contact-type recording methods such as thermal stamps and thermal heads have been known as recording methods on thermosensitive recording media that perform recording by causing changes in hue, reflectance, etc. by heating. Among these, thermal printers using thermal heads are widely used in the retail and logistics industries.

In thermal printers, the recording density on the recording medium can be adjusted by the amount of heat applied to the heating element for each dot of the thermal head, but printing may be affected by the heat accumulation of adjacent dots that are recorded immediately before and at the same time as the heating element records. Because it becomes darker, there is a method that corrects the amount of heat. For example, in order to avoid degrading the quality of multi-tone images, thermal printers have been proposed that can improve correction accuracy by counting the number of heating elements that provide heat within a predetermined time (e.g. , see Patent Document 1).

On the other hand, various proposals have been made regarding non-contact recording methods using lasers as methods for recording on other heat-sensitive recording media (for example, see Patent Document 2).

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser recording device that can suppress density unevenness in images and that does not easily damage a thermosensitive recording medium.

The laser recording device of the present invention as a means for solving the above problem is arranged such that the laser light source is directed on the thermal recording medium in a straight line based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium. while scanning the thermosensitive recording medium in one direction in the direction and in one direction perpendicular to the linear direction, or in one direction in the linear direction and in one direction perpendicular to the linear direction. a laser recording means for recording an image formed by a group of unit pixels that are colored by being irradiated with the laser light on the thermosensitive recording medium by irradiating the thermosensitive recording medium with the laser light while moving the thermosensitive recording medium;
When the laser recording means irradiates the heat-sensitive recording medium with laser light, control is performed to change the amount of irradiation energy of the laser light irradiated from the laser light source according to image brightness information of the image data. It is a means,
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. The image brightness value of DE1 is X1, the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
Corresponding to the one unit pixel E0, a second adjacent unit pixel E2 located on a straight line and adjacent to the other straight line direction, which is located parallel to and adjacent to the one straight line direction; An image brightness value included in second adjacent unit pixel data DE2 in the image data is X2, and a set amount of current supplied to the laser light source for recording the image of X2 is Y2 (Ah),
The second adjacent unit pixel E2 corresponds to the third adjacent unit pixel E3 located on the other straight line in the direction opposite to the first direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is determined by the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+(R ×Y3)] (wherein P, Q, and R represent arbitrary numbers from 0 to 1);
It is characterized by having the following.

According to the present invention, it is possible to provide a laser recording device that can suppress density unevenness in an image and that does not easily damage a thermosensitive recording medium.

FIG. 1 is a schematic diagram showing an example of a laser recording apparatus of the present invention. FIG. 2 is an explanatory diagram showing an example of dots recorded on a thermosensitive recording medium via an optical fiber by laser light irradiated onto the thermosensitive recording medium in the laser recording apparatus of the present invention. FIG. 3 is an explanatory diagram showing an example of the relationship between image data and dots recorded on a thermosensitive recording medium. FIG. 4 is a graph showing an example of the relationship between irradiation energy and print image density for a thermosensitive recording medium. FIG. 5A is a diagram for explaining a comparison between a conventional thermal head and a head of a laser recording apparatus according to the present invention. FIG. 5B is a diagram for explaining a comparison between a conventional thermal head and a head of a laser recording apparatus according to the present invention. FIG. 6 is a graph showing an example of the relationship between laser output and internal variables. FIG. 7 is a diagram for explaining an example of an image obtained by applying irradiation energy to a thermosensitive recording medium based on image data. FIG. 8 is a diagram for explaining an example of control of print image density correction by the laser recording apparatus of the present invention. FIG. 9 is a diagram for explaining an example of control of print image density correction by the laser recording apparatus of the present invention. FIG. 10 is a flowchart showing an example of print image density correction processing by the laser recording apparatus of the present invention. FIG. 11A is a diagram illustrating an example of comparing solid images with intermediate color development with and without output correction in the laser recording apparatus of the present invention. FIG. 11B is a diagram illustrating an example of comparing solid images with intermediate color development with and without output correction in the laser recording apparatus of the present invention. FIG. 12A is a diagram showing another example of the recording result in the print image density correction process by the laser recording apparatus of the present invention. FIG. 12B is a diagram illustrating an example of recording results by the laser recording apparatus of Comparative Example 1. FIG. 12C is a diagram illustrating an example of a recording result by the laser recording apparatus of Comparative Example 2. FIG. 13 is a diagram showing the structure of the white color-forming thermosensitive recording medium used in Example 3. FIG. 14 is a diagram showing an example of the structure of a black color-forming thermosensitive recording medium.

(Laser recording device, laser recording method)
The laser recording device of the present invention directs the laser light source on the thermal recording medium in one direction in a straight line and in a direction perpendicular to the straight line, based on position information on the thermal recording medium of image data to be recorded on the thermal recording medium. By irradiating the laser beam while scanning the thermosensitive recording medium in one direction in the linear direction or moving the thermosensitive recording medium in one direction in a linear direction and in one direction perpendicular to the linear direction, A laser recording means records an image formed by a group of unit pixels that develop color upon irradiation onto a heat-sensitive recording medium, and when the laser recording means irradiates laser light onto the heat-sensitive recording medium, image brightness information of the image data is recorded. A control means that performs control to change the amount of irradiation energy of a laser beam emitted from a laser light source according to the data, and is included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image. The image brightness value to be displayed is X0, and the set amount of current supplied to the laser light source for recording the image of X0 is Y0 (Ah), and for one unit pixel E0, the direction is opposite to the direction of The image brightness value of the first adjacent unit pixel data DE1 in the image data corresponding to the first adjacent unit pixel E1 located on the side and adjacent to it is X1, and is supplied to the laser light source for recording the image of X1. The set current amount to be set is Y1 (Ah), and for one unit pixel E0, a second unit pixel located on a straight line and adjacent to another straight line direction, which is parallel to and adjacent to one straight line direction. The image brightness value included in the second adjacent unit pixel data DE2 in the image data corresponding to the second adjacent unit pixel E2 is X2, and the set current amount to be supplied to the laser light source for recording the image of X2 is Y2 ( Ah), which corresponds to a third adjacent unit pixel E3 located on the other straight line in the opposite direction and adjacent to the second adjacent unit pixel E2, The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah), and one unit pixel The amount of current Z (Ah) supplied to the laser light source to actually record E0 is calculated using the following formula, Z = Y0 - [(P x Y1) + (Q x Y2) + (R x Y3)] (where , where P, Q, and R represent arbitrary numbers from 0 to 1).

The laser recording method of the present invention is based on the position information on the thermal recording medium of image data to be recorded on the thermal recording medium, and the laser light source is directed on the thermal recording medium in one direction in a linear direction and in a direction orthogonal to the linear direction. By irradiating the laser beam while scanning the thermosensitive recording medium in one direction in the linear direction or moving the thermosensitive recording medium in one direction in a linear direction and in one direction perpendicular to the linear direction, In the laser recording process in which an image formed by a group of unit pixels that develop color upon irradiation is recorded on a thermal recording medium, and in the laser recording process when laser light is irradiated onto the thermal recording medium, image brightness information of image data is used. A control step for controlling the amount of irradiation energy of laser light irradiated from a laser light source according to The image brightness value to be displayed is X0, the set amount of current supplied to the laser light source for recording the image of X0 is Y0 (Ah), and for one unit pixel E0, the direction is opposite to the one in the linear direction. The image brightness value of the first adjacent unit pixel data DE1 in the image data corresponding to the first adjacent unit pixel E1 located adjacent to the orientation side is X1, and the laser light source for recording the image of X1 is The set amount of current to be supplied is Y1 (Ah), and the unit pixel E0 is located on and adjacent to a straight line that is another straight line direction that is parallel to and adjacent to one straight line direction. The image brightness value included in the second adjacent unit pixel data DE2 in the image data corresponding to the second adjacent unit pixel E2 is X2, and the set amount of current supplied to the laser light source for recording the image of X2 is Y2. (Ah), which corresponds to the third adjacent unit pixel E3 located on the other straight line in the opposite direction and adjacent to the second adjacent unit pixel E2. , the image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah), and the unit of one is The amount of current Z (Ah) supplied to the laser light source to actually record pixel E0 is calculated using the following formula, Z = Y0 - [(P x Y1) + (Q x Y2) + (R x Y3)] ( However, in the formula, P, Q, and R represent arbitrary numbers from 0 to 1).

The laser recording method of the present invention can be suitably performed by the laser recording apparatus of the present invention, the laser recording step can be suitably carried out by a laser recording means, and the control step can be suitably carried out by a control means.
That is, the laser recording method of the present invention is synonymous with implementation using the laser recording apparatus of the present invention. Further, the laser recording device of the present invention is synonymous with implementing the laser recording method of the present invention.
Therefore, through the description of the laser recording apparatus of the present invention, details of the laser recording method of the present invention will also be made clear.

The laser recording device of the present invention is based on the knowledge that conventional non-contact recording methods using lasers have a problem in that it is difficult to correct the recording density in the same way as thermal printers. be.
Specifically, in conventional thermal printers, the amount of heat can be corrected by taking into account the effect of heat accumulation in the heat generating elements of adjacent dots that are printed immediately before and at the same time, but in recording methods using lasers, the amount of heat that accumulates can be corrected. The body does not exist. For this reason, it is difficult to apply a correction method similar to that used in conventional thermal printers to a recording method using a laser.

Therefore, the laser recording device of the present invention includes a laser recording means for recording on a heat-sensitive recording medium, and when the laser recording means irradiates the laser light onto the heat-sensitive recording medium, the laser light is emitted according to image brightness information of image data. and a control means for controlling to change the amount of irradiation energy. This control means controls a set amount of current supplied to a laser light source for recording an image of an image brightness value included in one unit pixel data of image data corresponding to one unit pixel of the image. Control is performed to change according to the set current amount for recording a pixel and a unit pixel adjacent to the pixel. Note that the image brightness value can be a value of brightness (brightness) in image data included in the image brightness information.
As a result, the laser recording device of the present invention can suppress uneven density of images by taking into account the heat generated according to the amount of energy irradiated with laser light for recording adjacent unit pixels, and It is possible to make the thermosensitive recording medium less likely to be damaged.

<Laser recording means>
The laser recording means directs the laser light source on the thermal recording medium in one direction in a linear direction and in one direction perpendicular to the linear direction, based on position information on the thermal recording medium of image data to be recorded on the thermal recording medium. Scan in both directions. Alternatively, the laser recording means moves the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction perpendicular to the linear direction. Then, as described above, the laser recording means irradiates the laser beam while scanning or moving, thereby thermally recording an image formed by a group of unit pixels that are colored by being irradiated with the laser beam. Record on a recording medium.

There are no particular restrictions on the method of recording on a thermal recording medium using a laser recording means, and it can be selected as appropriate depending on the purpose. For example, the thermal recording medium may be moved relative to the laser recording means. , the laser recording means may be moved relative to the thermosensitive recording medium.
Note that in the case of an optical fiber array having a plurality of laser light sources, the linear direction means a direction in which a plurality of optical fibers are arranged, or a direction perpendicular to the direction. Moreover, when there is one laser light source, it means the directions perpendicular to each other in which the laser light sources are scanned.
When recording an image on a thermosensitive recording medium, for example, a laser beam is scanned onto the thermosensitive recording medium, a portion irradiated with the laser beam generates heat, and the image is formed by being heated by thermal diffusion of the heat generating portion.

<<Laser light source>>
The laser light source is not particularly limited and can be appropriately selected depending on the purpose, and includes, for example, a semiconductor laser, a solid-state optical fiber laser, and the like. Among these, semiconductor lasers are preferable because they have wide wavelength selectivity, the laser light source itself is small for laser recording devices, and the devices can be made smaller and lower in price.

The wavelength of the laser beam is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 700 nm or more and 2,000 nm or less, more preferably 780 nm or more and 1,600 nm or less.

The output of the laser beam is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 W or more, and more preferably 3 W or more. When the output of the laser beam is 1 W or more, it is advantageous in terms of increasing the density of the image.

The shape of the spot drawing unit of the laser beam is not particularly limited and can be appropriately selected depending on the purpose. Examples include various polygons such as a circle, ellipse, triangle, square, pentagon, and hexagon. It will be done. Among these, circular and oval shapes are preferred.

-Laser beam spot diameter-
The spot diameter X (μm) of the laser beam irradiated by the laser recording means is not particularly limited and can be selected as appropriate, but it is preferably 90 μm or more and 150 μm or less in half width. When the spot diameter X of the laser beam is 90 μm or more and 150 μm or less in terms of half width, it is advantageous in that fine pictures and characters can be drawn while suppressing drawing unevenness due to variations in the laser spread angle (NA).
The spot diameter can be measured using, for example, a beam profiler.

As the laser recording means, it is preferable to have a plurality of laser light sources. An embodiment in which the laser recording means has a plurality of laser light sources is advantageous in that the recording time can be shortened compared to scanning with one laser light source.
In addition, when having multiple laser light sources, the energy of the laser light may vary even if the current flowing through each laser light source is the same, so it is important to make the energy of the laser light emitted from the multiple laser light sources uniform. It is preferable to correct it as follows.

There are no particular restrictions on the mode of having a plurality of laser light sources, and it can be selected as appropriate depending on the purpose, but it is preferable to have an optical fiber array in which optical fibers extending from a plurality of laser light sources are arranged in a straight line. In this aspect, since a plurality of laser light sources are arranged in a line in the straight direction, the printed image brightness correction is performed for one unit pixel by taking into account the thermal energy of both pixels adjacent in the straight direction. Make it.
Further, as another embodiment having a plurality of laser light sources, the laser light sources may be arranged in a planar manner and the heat-sensitive recording medium may be irradiated with laser light all at once to record an image. In this aspect, since a plurality of laser light sources are arranged in a planar manner, print image brightness correction is performed for one unit pixel in consideration of the thermal energy of surrounding pixels adjacent in all directions.

The optical fiber array is not particularly limited and can be selected as appropriate depending on the purpose.
The shortest distance (pitch) between the centers of optical fibers is preferably 1.0 mm or less, more preferably 0.5 mm or less, and even more preferably 0.03 mm or more and 0.15 mm or less.
When the shortest distance (pitch) between the centers of optical fibers is 1.0 mm or less, high-resolution recording becomes possible, and higher-definition images can be realized than in the past.
The number of optical fibers arranged in the optical fiber array is preferably 10 or more, more preferably 50 or more, and even more preferably 100 or more and 800 or less.
When the number of optical fibers arranged is 10 or more, high-speed recording becomes possible, and higher-definition images can be realized than in the past.
An optical system such as a lens may be provided downstream of the optical fiber array in order to control the spot diameter of the laser beam.

＜＜Image＞＞
An image is not particularly limited as long as it is visible information, and can be selected as appropriate depending on the purpose. ), barcodes, two-dimensional codes, etc.

<<Thermosensitive recording medium>>
The thermosensitive recording medium is not particularly limited as long as it can be recorded with laser light, and can be appropriately selected depending on the purpose.
Examples of the shape of the thermosensitive recording medium include a card shape, a tag shape, a label shape, a sheet shape, and a roll shape.
The structure, size, and material of the thermosensitive recording medium are not particularly limited and can be appropriately selected depending on the purpose.
Note that hereinafter, the thermosensitive recording medium may also be referred to as media.

<Control means>
The control means performs control to change the amount of irradiation energy of the laser light irradiated from the laser light source in accordance with image brightness information of image data when the laser recording means irradiates the heat-sensitive recording medium with laser light.

Specifically, the image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is set as X0, and the setting is supplied to a laser light source for recording the image of X0. Assume that the amount of current is Y0 (Ah; ampere hour).

Further, with respect to one unit pixel E0, first adjacent unit pixel data DE1 in the image data corresponding to a first adjacent unit pixel E1 located adjacent to and opposite to one direction in the linear direction. Let the image brightness value be X1. Let Y1 (Ah) be the set amount of current supplied to the laser light source for recording the image of X1.

Further, with respect to one unit pixel E0, an image corresponding to a second adjacent unit pixel E2 located on a straight line in another straight line direction parallel to and adjacent to one straight line direction. Let X2 be the image brightness value included in the second adjacent unit pixel data DE2 in the data. Let Y2 (Ah) be the set amount of current supplied to the laser light source for recording this X2 image.

Furthermore, the image corresponds to a third adjacent unit pixel E3 located on the other straight line in the opposite direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the data is assumed to be X3. Let Y3 (Ah) be the set amount of current supplied to the laser light source for recording this X3 image.

In this case, the control means calculates the amount of current Z (Ah) supplied to the laser light source to actually record one unit pixel E0 using the following formula, Z=Y0-[(P×Y1)+ (Q×Y2)+(R×Y3)]. However, in the formula, P, Q and R represent any number from 0 to 1.
As a result, the laser recording device of the present invention can suppress uneven density of images by taking into account the heat generated according to the amount of energy irradiated with laser light for recording adjacent unit pixels, and It is possible to make the thermosensitive recording medium less likely to be damaged.

P, Q and R are often larger than R when X0=X1=X2=X3. This is because E3, which is located diagonally, has little influence on E0.
Furthermore, P, Q, and R often satisfy Q≧P>R when X0=X1=X2=X3. This is because E1, which was irradiated with laser light immediately before, has a large influence on E0.

The control means determines the amount of current to be supplied and the amount of current to be supplied, which is expressed as the product of the magnitude of the current and the time for which the current is supplied, taking into account the heat generated according to the amount of energy irradiated with laser light for recording adjacent unit pixels. It is preferable to control the amount of supplied current within the set amount of current to be equal to or less than the set amount of current.
Note that the magnitude of current means a current value for irradiating laser light from a laser light source. Moreover, the current supply time means the time during which a current for irradiating laser light is passed through the laser light source.

There are no particular restrictions on the method of supplying current to the laser light source, and it can be selected as appropriate depending on the purpose.For example, a method using pulse control that changes the amount of time the current flows, and a continuous method that changes the magnitude of the current. Examples include a method using ass control.

Moreover, when the magnitude of the current is constant, the control means preferably controls the current supply time for the supplied current amount to be equal to or less than the current supply time for the set current amount. Control so that the current supply time is equal to or shorter than the set current amount is advantageous in that it can be easily realized by adjusting the duty using pulse control, for example.

It is preferable that the print image density value recorded on the thermosensitive recording medium is 0.5 or more and 1.4 or less in terms of OD value. When the print image density value is 0.5 or more and 1.4 or less in terms of OD value, it is advantageous in that recording can be performed with an appropriate recording density.

The hardware of the control means is not particularly limited as long as it can perform various controls and calculations, and can be appropriately selected depending on the purpose. Examples include a processor such as a CPU (Central Processing Unit). .
The control means realizes various functions by executing an OS (Operating System) and programs stored in an auxiliary storage device, etc., and executes various functions based on the control program for controlling the entire operation of the laser recording apparatus of the present invention. Execute processing.

Here, an example of the laser recording apparatus of the present invention used in the laser recording method of the present invention will be explained with reference to the drawings.
In addition, in each drawing, the same components are given the same reference numerals, and duplicate explanations may be omitted. Further, the number, position, shape, etc. of the following constituent members are not limited to this embodiment, and can be set to a preferable number, position, shape, etc. for implementing the present invention.

FIG. 1 is a schematic diagram showing an example of a laser recording apparatus having an optical fiber array of the present invention.
As shown in FIG. 1, in the laser recording apparatus 1, a laser beam is emitted from an optical fiber array 11 arranged in a main scanning direction orthogonal to a sub-scanning direction indicated by an arrow in the figure, which is a moving direction of a thermosensitive recording medium 31. The medium 31 is irradiated to record an image made up of drawing units. Note that laser beams are guided from a plurality of laser light sources 13 to the optical fiber array 11 via optical fibers 12 .
The optical fiber array 11 has one or more array heads 11a arranged in a line in the main scanning direction, and the spot diameter of the laser beam can be controlled on the optical path of the laser beam irradiated from the array head 11a. It has an optical system.

The energy applied to the laser light source 13 is not entirely converted into laser light, but is normally converted into heat, causing the laser light source 13 to generate heat. Therefore, the cooling means 21 is used to cool the laser light sources 13. However, by using the optical fiber array 11, each laser light source 13 can be placed apart from each other to reduce the influence of multiple adjacent irradiations, and the laser light sources 13 can be cooled. This can be carried out efficiently, temperature rise of the laser light source 13 can be avoided, and variations in the output of the laser beam can be reduced, so density unevenness and white spots in recording can be improved.
The laser recording device 1 controls the length of the drawing unit in the sub-scanning direction based on the spot diameter of the laser beam on the thermal recording medium 31 and the period and duty ratio of the pulse signal that the driving means 14 inputs to the laser light source 13. The ends of drawing units that are adjacent in the sub-scanning direction are recorded in an overlapping manner in the sub-scanning direction.

The laser light source 13 is a semiconductor laser, and the wavelength of the laser light it irradiates is 957 nm, and the output of the laser light is 10W.
The output of the laser beam refers to the irradiation energy, and is the average output measured by a power meter.
The output can be controlled in two ways: peak power and duty (=laser emission time/cycle time).

The driving means 14 outputs a pulse signal generated based on the driving signal inputted from the control means 15 to the laser light source 13, thereby driving the laser light source 13. The driving means 14 is provided for each of the plurality of laser light sources 13, and drives each of the laser light sources 13 independently.

The control means 15 outputs a drive signal generated based on the image information transmitted from the main control means 16 to the drive means 14, and controls the drive means 14.
The main control means 16 includes a CPU (Central Processing Unit) that controls each operation of the laser recording apparatus 1, and executes various processes based on a control program for controlling the operations of the laser recording apparatus 1 as a whole.

The main control means 16 is communicably connected to the control means 15 and transmits image information and the like to the control means 15.

The power supply means 17 supplies power to the control means 15 and the like.

The cooling means 21 is disposed below the driving means 14 and the laser light source 13, and cools the driving means 14 and the laser light source 13 using a constant temperature liquid circulated by a chiller 22. In the chiller method, only cooling is performed without heating. Therefore, although the temperature of the light source does not become higher than the set temperature of the chiller, the temperature of the cooling means 21 and the laser light source 13 in contact may fluctuate due to the influence of the environmental temperature. On the other hand, when a semiconductor laser is used as the laser light source 13, a phenomenon occurs in which the laser output changes depending on the temperature of the laser light source 13 (as the temperature of the laser light source becomes lower, the laser output increases). In order to control, the temperature of the laser light source 13 or the temperature of the cooling means 21 is measured, and according to the result, an input signal to a drive circuit that controls the laser output is controlled so that the laser output is constant. It is preferable to perform normal image formation.
The conveyance means 41 conveys the thermal recording medium 31 in the sub-scanning direction.

FIG. 2 is an explanatory diagram showing an example of dots recorded on a thermosensitive recording medium via an optical fiber by laser light irradiated onto the thermosensitive recording medium in the laser recording apparatus of the present invention.
As shown in FIG. 2, the laser light emitted from the laser light source forms an image on an image plane (beam spot) indicated by a black circle in FIG. 2 via an optical fiber and a lens unit. The laser light focused on the beam spot is absorbed by the thermosensitive recording medium and converted into heat. When the converted heat exceeds a threshold value necessary for color development, the thermosensitive recording medium develops color and a dot, which is a unit pixel, is formed.
Note that the structure of the optical fiber consists of a core portion at the center through which laser light passes, and a cladding layer provided around the outer periphery of the core portion.

The reason why the colored area is wider than the focused beam spot is that when the heat-sensitive recording medium absorbs heat, the heat is diffused and exceeds the threshold value to the peripheral area.
Also, the reason why the coloring area of the dot shape is wider in the sub-scanning direction than in the main scanning direction is because the thermal recording medium or the laser light source moves while irradiating the laser beam. This is because the laser beam moves on the thermosensitive recording medium and the heat spreads in the sub-scanning direction.

FIG. 3 is an explanatory diagram showing an example of the relationship between image data and dots recorded on a thermosensitive recording medium. In the example shown in FIG. 3, for example, the moving direction of the thermosensitive recording medium is a linear direction (the sub-scanning direction of the printing surface), and the direction in which the plurality of laser light sources (array heads) in the optical fiber array are arranged in a line is is the orthogonal direction (main scanning direction).
As shown in FIG. 3, the laser recording device irradiates a thermal recording medium moving in the sub-scanning direction with laser light using a plurality of laser light sources arranged in orthogonal directions based on input image data. , form an image all at once. At this time, the laser recording device records the image on the thermal recording medium by aligning the direction of the input image data with the moving direction of the thermal recording medium.
This laser recording device outputs a pulse signal based on the brightness value of the image data to the laser light source, thereby suppressing unevenness in image density. A control means performs control to change the amount of irradiation energy. This control will be explained in detail with reference to FIGS. 8 to 10.
Further, the thermosensitive recording medium in this embodiment is a recording medium containing a material that converts light into heat. Next, this thermosensitive recording medium will be explained.

FIG. 4 is a graph showing an example of the relationship between irradiation energy and print image density for a thermosensitive recording medium. The graph shown in FIG. 4 shows the color density characteristics of an image with respect to irradiation energy on a thermosensitive recording medium, where the vertical axis is the color density value (OD) of the image, and the horizontal axis is the laser light irradiated onto the thermosensitive recording medium. is the amount of irradiation energy.
As shown in FIG. 4, in the heat-sensitive recording medium, as the irradiation energy of the laser light irradiated from the laser light source is increased, the color density value of the image gradually increases, and the color density value of the image gradually becomes saturated. Furthermore, if excessive irradiation energy is applied, the thermosensitive recording medium will be damaged.
In addition, in the graph shown in Figure 4, if the irradiation energy is adjusted to utilize the portion (intermediate color development) from when the printed image density value starts to increase until the printed image density value is saturated, the recorded image can be expressed in gradation. It is possible to do so. The laser recording device of this embodiment can be suitably used to express gradations using intermediate color development in a manner different from that of conventional thermal heads.

FIGS. 5A and 5B are diagrams for explaining a comparison between a conventional thermal head and a head of a laser recording apparatus according to the present invention.
As shown in Figure 5A, in conventional thermal heads, the heating element is located close to the thermal recording medium, and a cover is often attached to cover the heating element, so the environment near the thermal recording medium is heated. It has a structure that prevents it from escaping and is stable in high ambient temperatures. Therefore, even if there is some variation in the amount of heat generated by the heating element, the stable ambient temperature makes it easy to suppress unevenness in image density, and it is easy to improve the quality of images expressed in gradation. On the other hand, as shown in FIG. 5B, in a non-contact recording device using a laser, only the portion of the thermosensitive recording medium that is irradiated with the laser beam generates heat, and the distance over which the laser beam is focused by the optical system is limited. Since this is necessary, the structure allows heat to escape from the vicinity of the thermosensitive recording medium more easily than in conventional thermal heads. For this reason, it is difficult to apply a correction method similar to that used in conventional thermal printers to non-contact recording devices that use lasers. Furthermore, when using an optical fiber array, when trying to record an image with gradation, the irradiation energy often varies even if the same current is passed through each laser light source, so when recording a solid image with intermediate coloring, it is difficult to , the density unevenness of the image becomes large. Therefore, in the laser recording apparatus of this embodiment, correction as shown in FIG. 6 is performed so that the irradiation energy is uniform even if the same current is passed through each laser light source.

FIG. 6 is a graph showing an example of the relationship between laser output and internal variables. FIG. 6 shows the variation in the irradiation energy of each laser light source, and shows the measurement results during output correction of two representative laser light sources among the plurality of laser light sources.
Note that the output correction is to make uniform the output variations (variations in irradiation energy) of each laser light source that irradiates the thermosensitive recording medium. Further, a laser power meter (50 (150) A-BB-26, manufactured by OPHIR) was used for the measurement.

The laser recording device of this embodiment includes a storage section inside, and can store adjustment variables (hereinafter referred to as internal variables) for each laser light source. By increasing or decreasing the value of this internal variable, the magnitude of the current flowing through the corresponding laser light source can be increased or decreased by the driving means.
This internal variable is determined based on the result of measuring the irradiation energy on the surface of the thermosensitive recording medium using a laser power meter so as to make the irradiation energy of each laser light source uniform. In addition to the internal variables, the measurement result of the irradiation energy on the surface of the thermosensitive recording medium is reflected in the setting of the current value and duty of each laser light source. Irradiate laser light from each laser light source to the set current value and duty, repeat the measurement of irradiation energy while increasing or decreasing the internal variables until the target irradiation energy is reached, and measure the internal variables that have reached the target irradiation energy. Store it in the storage unit.

FIG. 7 is a diagram for explaining an example of an image obtained by applying irradiation energy to a thermosensitive recording medium based on image data.
FIG. 7 shows that even if the irradiation energy of each laser light source is made uniform by internal variables, density unevenness occurs in the image when the image is composed of clustered dots. If the image is a single dot, no density unevenness will occur in the image, but if the image is a group of dots, it is recorded so that there are no white spots in the image, so some dots may overlap. It is necessary to irradiate the heat-sensitive recording medium with laser light. For this reason, the center of a cluster of dots is greatly affected by heat from the surrounding dots, making it easy to damage the thermosensitive recording medium when recording an image.
Therefore, if you simply reduce the overall irradiation energy for the image data, excessive energy will be less likely to occur for clustered dots, but on the other hand, for individual dots, the irradiation energy will be insufficient and the printed image density will become low. . Therefore, it is necessary to perform a correction that takes into account the influence of heat at the center of the group of dots, as shown in FIG.

FIG. 8 is a diagram for explaining an example of control of print image density correction by the laser recording apparatus of the present invention.
As shown in the upper left diagram of FIG. 8, the input image data is 8-bit monochrome of 5 pixels x 5 pixels, and the 3 pixels x 3 pixels in the center represent a solid image with a luminance value of 0. In this image data, rows correspond to a linear direction (sub-scanning direction), and columns correspond to an orthogonal direction (main-scanning direction) perpendicular to the linear direction. Here, if we do not perform print image density correction on this image data and set a pulse signal that determines the amount of current supplied to the laser light source, the duty ratio will be 100% for the central 3 pixels x 3 pixels (Figure 8 (see figure on the bottom left). Here, the duty ratio of 100% refers to the amount of current required to obtain a saturated print image density in each pixel. If the pulse signal is set in this way, the irradiation energy will be excessive at the pixel in the 3rd row and 3rd column "hereinafter expressed as (3, 3)" as shown in Figure 7, which may damage the thermal recording medium. I'll let you.

Therefore, the control means sets a set amount of current to be supplied to the laser light source for recording an image having an image brightness value included in one unit pixel data of the image data corresponding to one unit pixel of the image. Control is performed to change according to the set current amount for recording a unit pixel and an adjacent unit pixel. With this print image density correction, as shown in the lower right diagram of FIG. It is possible to record a solid image with suppressed damage, and it is possible to make the heat-sensitive recording medium less likely to be damaged. Note that the example shown in FIG. 8 is an example in which an optical fiber array for irradiating laser light has three laser exit ports adjacent to each other in the orthogonal direction (main scanning direction).

FIG. 9 is a diagram for explaining an example of control of print image density correction by the laser recording apparatus of the present invention.
As shown in FIG. 9, if the pixel at (3, 3) is one unit pixel E0 of interest, the pixel data of one unit pixel E0 is DE0, and the duty when recording without print image density correction is Let it be D0. Also, the surrounding pixels of E0 (3,2), (2,3), (2,2), (2,4), (3,4), (4,3), (4,2) , (4,4) are assumed to be E1, E2, E3, E4, E5, E6, E7, and E8. In addition, those pixel data are set as DE1, DE2, DE3, DE4, DE5, DE6, DE7, DE8, and the Duty when recording without print image density correction is D1, D2, D3, D4, D5, D6, D7. , D8.

Here, the positional relationship between E0 of interest and E1, E2, E3, E4, E5, E6, E7, and E8 adjacent to E0 is as shown in FIG. It can be classified according to the positional relationship in the direction (sub-scanning direction) and the orthogonal direction (main-scanning direction). Here, an example is used in which the optical fiber array has three laser beam exit ports adjacent to each other in the orthogonal direction (main scanning direction).
Specifically, they can be grouped as follows.
"E1": A group located adjacent to and opposite to one direction (scanning direction) in the scanning direction (linear direction; sub-scanning direction) of laser light with respect to E0. That is, it is located upstream of E0 in the sub-scanning direction and is irradiated with laser light before E0.
"E2 and E6": Groups located adjacent to E0 in the orthogonal direction (main scanning direction). That is, the laser beam is irradiated simultaneously with E0.
"E3 and E7": Adjacent to E0 in parallel to the orthogonal direction (main scanning direction) and opposite to one direction (scanning direction) in the scanning direction (linear direction; sub-scanning direction) of the laser beam. A group located on the line located at In other words, a group located adjacent to E1 in the orthogonal direction (main scanning direction). That is, the laser beam is irradiated simultaneously with E1.
"E5": A group located downstream and adjacent to E0 in the sub-scanning direction. That is, the laser beam is irradiated after E0.
"E4 and E8": Located parallel to E0 in the orthogonal direction (main scanning direction) and adjacent to one direction (scanning direction) in the scanning direction (linear direction; sub-scanning direction) of the laser beam A group located on a line. In other words, the group is located adjacent to E5 in the orthogonal direction (main scanning direction). That is, the laser beam is irradiated simultaneously with E5.

The energy given by each group to E0 of interest is as follows.
ΔE1=P×(E1)
ΔE2=Q×(E2+E6)
ΔE3=R×(E3+E7)
ΔE4=S×(E4+E8)
ΔE5=T×(E5)
However, the coefficients P to T are calculated from the interval between the recorded dots, the laser spot diameter, the size of the recorded dots, the scanning speed in the main scanning direction or the sub-scanning direction, the distance from E0 of interest, and the like.
Therefore, the thermal energy received from the surrounding dots when recording E0 of interest can be determined by the following equation: Eout=E0-ΔE1-ΔE2-ΔE3-ΔE4-ΔE5.

In the above, we have explained the printed image density correction in the case of the optical fiber array mode, but the invention is not limited to this. For example, in the mode of one laser light source, laser light is first irradiated in the sub-scanning direction from the first line, and then Consider a case in which scanning is repeated in which the second row is irradiated with laser light in the sub-scanning direction. In this case, it is sufficient to consider the thermal energy received from E1 and E5, which are the dots to be drawn immediately before and after, so by setting ΔE1=P×(E1) and ΔE5=T×(E5), the following equation, Eout=E0− It may be determined by ΔE1-ΔE5.

Next, the flow of print image density correction processing of the laser irradiation program for laser recording of the present invention will be explained.

(Laser irradiation program for laser recording)
The laser recording laser irradiation program of the present invention is suitably executed to implement the laser recording method of the present invention.
That is, the laser recording laser irradiation program of the present invention can execute the laser recording method of the present invention by using a computer or the like as a hardware resource. Further, the laser recording laser irradiation program of the present invention may be executed by at least one of one or more computers and servers.
In addition, in the processing by the laser irradiation program for laser recording of this embodiment, output correction is performed in advance using internal variables in each laser light source.

FIG. 10 is a flowchart showing an example of print image density correction processing by the laser recording apparatus of the present invention.

In step S101, when the input unit receives data of a BMP format image (BMP image), the control means moves the process to S102.

In step S102, the control means converts the received BMP image data into image brightness values of each pixel data, and then shifts the process to S103.
Specifically, if the bit depth of the received image data is 8 bits, the image brightness value takes a value from 0 to 255. The laser recording device has a function that allows the user to set whether to perform irradiation with the maximum irradiation energy at either an image brightness value of 0 or 255.

In step S103, the control means converts the converted image brightness value into a duty ratio for each pixel in the input image data, and then moves the process to S104.
As a formula for converting the image brightness value into a duty ratio, for example, when maximum irradiation is performed at an image brightness value of 255, the formula is expressed as follows: Duty ratio = (image brightness value) / 255 × 100 (%) be able to. Further, in the case of maximum irradiation with an image brightness value of 0, it can be expressed as the following formula: Duty ratio=(255−image brightness value)/255×100(%). Note that when the print image density correction is not performed, the value of the duty ratio obtained here is used. Here, it is assumed that print image density correction is to be performed, and the process moves to step S104.

In step S104, the control means refers to the duty ratios of surrounding pixels for one pixel, and then moves the process to S105.

In step S105, the control means determines the duty ratio of one pixel using the following equation: Eout=E0-ΔE1-ΔE2-ΔE3-ΔE4-ΔE5, and then shifts the process to S106. That is, in step S105, based on the duty ratio before correction of the eight surrounding pixels of the recording pixel referenced in step S104, from the surroundings calculated by the following equation, Eout=E0-ΔE1-ΔE2-ΔE3-ΔE4-ΔE5. Control is performed to set the duty ratio by decreasing it from 100% based on the received thermal energy.

In step S106, the control means irradiates each pixel with a laser beam of irradiation energy having a set duty ratio.
In the example shown in FIG. 10, for example, the BMP image may be printed by repeating steps S102 to S106 for each pixel in the received BMP image data.
Note that the correction to the BMP image data is performed every time the BMP image data is input.

Examples of the present invention will be described below, but the present invention is not limited to these Examples in any way.

(Example 1)
In an optical fiber array using the laser recording apparatus shown in FIGS. 1 to 3, 32 fiber-coupled LDs with a maximum output of 30 W are arranged in the main scanning direction as a plurality of laser light sources, and the pitch interval X between adjacent optical fibers is 127 μm. , the internal variables for each fiber coupling LD were changed, and the output was corrected so that the irradiation energy was uniform. The peak power of the laser beam was 5W. Further, the focus position was adjusted to fix the spot diameter to 105 μm, and the optical fiber used had a diameter of 125 μm and a core portion diameter of 105 μm.
A thermosensitive recording medium in which the content of the photothermal conversion material is adjusted so as to produce a saturated color with an irradiation energy of 5 W for one laser light source, using a laser recording device with output correction, at a moving speed of the thermosensitive recording medium of 3 m/sec. In contrast, a solid image with intermediate coloring was recorded. A photograph of the recorded solid image is shown in FIG. 11A.

(Example 2)
A solid image with intermediate coloring was recorded in the same manner as in Example 1, except that no output correction was performed to make the irradiation energy uniform. A photograph of the recorded solid image is shown in FIG. 11B.

As shown in FIGS. 11A and 11B, it can be seen that when the output correction is performed, the density unevenness of the solid image is improved more than when the output correction is not performed.

Next, printed image density unevenness was evaluated for images including solid image areas and thin line areas.

(Example 3)
In Example 1, the thermal recording medium was replaced with the following white-coloring thermal recording medium, and the printed image was obtained by considering the output correction performed in Example 1 and the influence of E1 to E8 on E0 shown in FIG. The same procedure was used as in Example 1, except that the density was corrected, the image was taken with a black mount placed underneath, and the intermediately colored solid image was replaced with an image that included solid image areas and fine line areas. The recorded image was evaluated as follows, and the results are shown in Table 1. Further, a photograph of the recorded image is shown in FIG. 12A.
Note that the coefficients P to T for print image density correction were set to P=0.04, Q=0.07, R=0.035, S=0.001, and T=0.001, respectively.

<White-chromatic heat-sensitive recording medium>
The structure of the white coloring thermosensitive recording medium used in Example 3 is shown in FIG. 13. As shown in FIG. A surface active layer of 1 .mu.m thick was coated to improve the properties, and a recording layer of 4 .mu.m thick, an oxygen barrier layer of 2 .mu.m thick, an adhesive layer of 7 .mu.m thick, and a protective layer of 12 .mu.m thick were laminated thereon in this order. Further, the recording layer contained calcium carbonate and a styrene-acrylic copolymer. The same transparent PET material used for the base material was used for the protective layer.

<Visibility evaluation>
The recorded images were visually evaluated according to the following criteria. The results are shown in Table 1.
[Evaluation criteria]
○: Clear △: Some areas are unclear ×: Not clear

<Damage evaluation>
The recorded images were visually evaluated according to the following criteria. The results are shown in Table 1.
[Evaluation criteria]
○: Not damaged △: Some parts are damaged ×: Damaged

<Barcode readability evaluation>
The recorded images were evaluated using a barcode reader (THIR-6780, manufactured by Mars Stoken Solutions Co., Ltd.) according to the following criteria. The results are shown in Table 1.
[Evaluation criteria]
○: Can be scanned 10 times without any problem ×: Cannot be read even after 10 scans

(Comparative example 1)
In Example 3, printing was performed in the same manner as in Example 3, except that the print image density correction was not performed and the output of the laser light source was adjusted so that the details of the image became clear, including solid image areas and thin line areas. An image was recorded, and the recorded image was evaluated as follows, and the results are shown in Table 1. Further, a photograph of the recorded image is shown in FIG. 12B.

(Comparative example 2)
In Example 3, solid image areas and fine line areas were processed in the same manner as in Example 3, except that the output of the laser light source was adjusted so that the solid image areas of the image became clear without performing print image density correction. The recorded image was evaluated as follows, and the results are shown in Table 1. Further, a photograph of the recorded image is shown in FIG. 12C.

From the results in Table 1 and FIGS. 12A to 12C, it can be seen that in Comparative Example 1, the output of the laser light source was adjusted to make the thin line area clearer, so uneven print image density occurred in some areas, and in the solid image area. The thermosensitive recording medium was damaged and the barcode readability was poor. Even if the irradiation energy of all the laser light sources is lowered so as not to damage the solid image area, sufficient coloring cannot be obtained in the thin line areas including small characters due to insufficient irradiation energy.

It can be seen that in Comparative Example 2, the output of the laser light source was adjusted so that the solid image area became clearer, so that damage to the heat-sensitive recording medium in the solid image area was improved compared to Comparative Example 1. However, it can be seen that the visibility is poor in the thin line areas, and there is some unevenness in dot area and printed image density. Furthermore, since thin lines cannot be drawn, barcode readability has not been improved.

In Example 3, the printed image density was corrected and the irradiation energy of the laser light source was optimized, so the thermosensitive recording medium was not damaged and the visibility of the barcode and characters was good.

Table 2 summarizes the results of Examples 1 to 3 and Comparative Examples 1 to 2.
From this, it was found that the laser recording apparatus of the present invention can suppress density unevenness in images and can make the thermosensitive recording medium less likely to be damaged.

Further, in Example 3, Comparative Example 1, and Comparative Example 2, a white coloring thermosensitive recording medium was used, but the present invention is not limited to this, and for example, a black coloring thermosensitive recording medium may be used.
Examples of the black coloring thermosensitive recording medium include those shown in FIG. 14.
As shown in FIG. 14, as an example of a black color-forming thermosensitive recording medium, a recording layer with an average thickness of 3.2 μm is coated on a PET base material (white), and a recording layer An example of this is a structure in which a protective layer having an average thickness of 2 μm is coated on the surface. The recording layer may contain a color developer, a leuco dye, and a photothermal conversion material.

As explained above, the laser recording device of the present invention directs the laser light source in one direction in a straight line on the thermal recording medium based on the position information on the thermal recording medium of the image data to be recorded on the thermal recording medium. Irradiate laser light while scanning in one direction perpendicular to the linear direction, or while moving the thermosensitive recording medium in one direction in the linear direction and one direction in the direction perpendicular to the linear direction. By this, a laser recording means records an image formed by a group of unit pixels colored by being irradiated with a laser beam onto a thermosensitive recording medium, and when the laser recording means irradiates the laser beam onto the thermosensitive recording medium, the image is A control means that performs control to change the amount of irradiation energy of laser light irradiated from a laser light source according to image brightness information of the data of the image, the control means performing control to change the irradiation energy amount of the laser light irradiated from the laser light source according to the image brightness information of the data of the image, the control means The image brightness value included in the unit pixel data DE0 is X0, the set amount of current supplied to the laser light source for recording the image of X0 is Y0 (Ah), and the linear direction for one unit pixel E0 is The image brightness value of the first adjacent unit pixel data DE1 in the image data corresponding to the first adjacent unit pixel E1 located in the opposite direction and adjacent to the one direction in is X1, and the image of X1 is recorded. The set amount of current supplied to the laser light source for the purpose of and the image brightness value included in the second adjacent unit pixel data DE2 in the image data corresponding to the second adjacent unit pixel E2 located adjacently is X2, and is supplied to the laser light source for recording the image of X2. The set current amount to be set is Y2 (Ah), and the third adjacent unit pixel E2 is located on the other straight line direction, opposite to the first direction, and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data corresponding to the unit pixel E3 is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah). The amount of current Z (Ah) supplied to the laser light source to actually record one unit pixel E0 is calculated using the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+( R×Y3)] (where P, Q, and R represent arbitrary numbers from 0 to 1).
As a result, the laser recording device of the present invention can suppress uneven density of images by taking into account the heat generated according to the amount of energy irradiated with laser light for recording adjacent unit pixels, and It is possible to make the thermosensitive recording medium less likely to be damaged.

Examples of aspects of the present invention are as follows.
<1> Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in one direction in a direction perpendicular to the linear direction. or by irradiating the laser beam while scanning the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. laser recording means for recording on the thermosensitive recording medium an image formed by a group of unit pixels that develop color upon being irradiated with;
When the laser recording means irradiates the heat-sensitive recording medium with laser light, control is performed to change the amount of irradiation energy of the laser light irradiated from the laser light source according to image brightness information of the image data. It is a means,
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. The image brightness value of DE1 is X1, the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
The second adjacent unit pixel E2, which corresponds to the second adjacent unit pixel E2 located on a straight line in the other straight line direction, which is located parallel to and adjacent to the one straight line direction, with respect to the one unit pixel E0. An image brightness value included in second adjacent unit pixel data DE2 in image data is X2, and a set amount of current supplied to the laser light source for recording the image of X2 is Y2 (Ah),
The second adjacent unit pixel E2 corresponds to the third adjacent unit pixel E3 located on the other straight line in the direction opposite to the first direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is determined by the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+(R ×Y3)] (wherein P, Q, and R represent arbitrary numbers from 0 to 1);
This is a laser recording device characterized by having the following features.
<2> The laser recording apparatus according to <1>, wherein the P, Q, and R are larger than the R when X0=X1=X2=X3.
<3> The <3> controlled so that the supplied current amount out of the supplied current amount and the set current amount, which are represented by the product of the magnitude of the current and the current supply time, is equal to or less than the set current amount. The laser recording device according to any one of items 1 to 2 above.
<4> The current according to <3>, wherein the magnitude of the current is constant, and the time for supplying the current at the amount of supplied current is controlled to be equal to or less than the time for supplying the current at the set amount of current. This is a laser recording device.
<5> The laser recording means has a plurality of the laser light sources,
The laser recording device according to any one of <1> to <4>, wherein energy of the laser light emitted from a plurality of the laser light sources is corrected to be uniform.
<6> The image brightness value included in the image data to be recorded on the thermosensitive recording medium is 0.5 or more and 1.4 or less in terms of OD value, according to any one of <1> to <5> above. It is a laser recording device.
<7> The laser recording device according to any one of <1> to <6>, wherein the spot diameter X (μm) of the laser beam irradiated by the laser recording means is 90 μm or more and 150 μm or less in half width. It is.
<8> Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in a direction perpendicular to the linear direction. or by irradiating the laser beam while scanning the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. laser recording means for recording on the thermosensitive recording medium an image formed by a group of unit pixels that develop color upon being irradiated with;
When the laser recording means irradiates the heat-sensitive recording medium with laser light, control is performed to change the amount of irradiation energy of the laser light irradiated from the laser light source according to image brightness information of the image data. It is a means,
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. When the image brightness value of DE1 is X1 and the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is calculated using the following formula: Z=Y0-(P×Y1) (wherein, P is (representing any number from 0 to 1),
This is a laser recording device characterized by having the following features.
<9> Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in a direction perpendicular to the linear direction. or by irradiating the laser beam while scanning the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. a laser recording step of recording on the thermosensitive recording medium an image formed by a group of unit pixels that have developed color upon being irradiated with;
When irradiating laser light onto the thermosensitive recording medium in the laser recording step, control is performed to change the amount of irradiation energy of the laser light irradiated from the laser light source according to image brightness information of the image data. It is a process,
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. The image brightness value of DE1 is X1, the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
The second adjacent unit pixel E2, which corresponds to the second adjacent unit pixel E2 located on a straight line in the other straight line direction, which is located parallel to and adjacent to the one straight line direction, with respect to the one unit pixel E0. An image brightness value included in second adjacent unit pixel data DE2 in image data is X2, and a set amount of current supplied to the laser light source for recording the image of X2 is Y2 (Ah),
The second adjacent unit pixel E2 corresponds to the third adjacent unit pixel E3 located on the other straight line in the direction opposite to the first direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is determined by the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+(R ×Y3)] (in the above formula, P, Q, and R represent any number from 0 to 1);
This is a laser recording method characterized by including the following.
<10> Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in one direction in a direction perpendicular to the linear direction. or by irradiating the laser beam while scanning the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. A laser irradiation program for use in laser recording for recording on the thermosensitive recording medium an image formed by a group of unit pixels that develop color upon irradiation, the program comprising:
When irradiating the laser light onto the heat-sensitive recording medium, control is performed to change the irradiation energy amount of the laser light irradiated from the laser light source according to image brightness information of the image data;
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. The image brightness value of DE1 is X1, the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
The second adjacent unit pixel E2, which corresponds to the second adjacent unit pixel E2 located on a straight line in the other straight line direction, which is located parallel to and adjacent to the one straight line direction, with respect to the one unit pixel E0. An image brightness value included in second adjacent unit pixel data DE2 in image data is X2, and a set amount of current supplied to the laser light source for recording the image of X2 is Y2 (Ah),
The second adjacent unit pixel E2 corresponds to the third adjacent unit pixel E3 located on the other straight line in the direction opposite to the first direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah),
The amount of current Z (Ah) supplied to the laser light source in order to actually record the one unit pixel E0 is calculated using the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+(R ×Y3)] (wherein P, Q, and R represent any number from 0 to 1),
This is a laser irradiation program for laser recording characterized by the following.

The laser recording device according to any one of <1> to <8>, the laser recording method according to <9>, and the laser irradiation program for laser recording according to <10> solve the above-mentioned conventional problems. It is possible to solve the problem and achieve the object of the present invention.

1 Laser recording device 11 Optical fiber array head 11a Array head 12 Optical fiber 13 Laser light source 14 Drive means 15 Control means 16 Main control means 17 Power supply means 21 Cooling means 22 Chiller 31 Thermosensitive recording medium 41 Transport means

Japanese Patent Application Publication No. 2000-211174 JP 2017-140833 Publication

Claims (10)

Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in one direction in a direction perpendicular to the linear direction. or by irradiating the laser beam while moving the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. laser recording means for recording on the thermosensitive recording medium an image formed by a group of unit pixels that are colored in response;
When the laser recording means irradiates the heat-sensitive recording medium with laser light, control is performed to change the amount of irradiation energy of the laser light irradiated from the laser light source according to image brightness information of the image data. It is a means,
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. The image brightness value of DE1 is X1, the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
Corresponding to the one unit pixel E0, a second adjacent unit pixel E2 located on a straight line and adjacent to the other straight line direction, which is located parallel to and adjacent to the one straight line direction; An image brightness value included in second adjacent unit pixel data DE2 in the image data is X2, and a set amount of current supplied to the laser light source for recording the image of X2 is Y2 (Ah),
The second adjacent unit pixel E2 corresponds to the third adjacent unit pixel E3 located on the other straight line in the direction opposite to the first direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is determined by the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+(R ×Y3)] (wherein P, Q, and R represent arbitrary numbers from 0 to 1);
A laser recording device comprising: The laser recording apparatus according to claim 1 , wherein the P, Q and R are larger than the R when X0=X1=X2=X3. Claims 1 to 2, wherein the supplied current amount out of the supplied current amount and the set current amount, which is expressed as a product of the magnitude of the current and the current supply time, is controlled to be equal to or less than the set current amount. The laser recording device according to any one of. 4. The laser recording device according to claim 3, wherein the magnitude of the current is constant, and the time for supplying the current at the amount of supplied current is controlled to be equal to or less than the time for supplying the current at the set amount of current. . The laser recording means has a plurality of the laser light sources,
5. The laser recording apparatus according to claim 1, wherein energy of the laser light emitted from a plurality of the laser light sources is corrected to be uniform. 6. The laser recording apparatus according to claim 1, wherein the image luminance value included in the data of the image to be recorded on the thermosensitive recording medium is 0.5 or more and 1.4 or less in terms of OD value. 7. The laser recording apparatus according to claim 1, wherein a spot diameter X (μm) of the laser beam irradiated by the laser recording means is 90 μm or more and 150 μm or less in half width. Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in one direction in a direction perpendicular to the linear direction. or by irradiating the laser beam while moving the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. laser recording means for recording on the thermosensitive recording medium an image formed by a group of unit pixels that are colored in response;
When the laser recording means irradiates the heat-sensitive recording medium with laser light, control is performed to change the amount of irradiation energy of the laser light irradiated from the laser light source according to image brightness information of the image data. It is a means,
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. When the image brightness value of DE1 is X1 and the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is calculated using the following formula: Z=Y0-(P×Y1) (wherein, P is (representing any number from 0 to 1),
A laser recording device comprising: Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in one direction in a direction perpendicular to the linear direction. or by irradiating the laser beam while moving the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. a laser recording step of recording on the thermosensitive recording medium an image formed by a group of unit pixels that have received color;
When irradiating laser light onto the thermosensitive recording medium in the laser recording step, control is performed to change the amount of irradiation energy of the laser light irradiated from the laser light source according to image brightness information of the image data. It is a process,
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. The image brightness value of DE1 is X1, the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
Corresponding to the one unit pixel E0, a second adjacent unit pixel E2 located on a straight line and adjacent to the other straight line direction, which is located parallel to and adjacent to the one straight line direction; An image brightness value included in second adjacent unit pixel data DE2 in the image data is X2, and a set amount of current supplied to the laser light source for recording the image of X2 is Y2 (Ah),
The second adjacent unit pixel E2 corresponds to the third adjacent unit pixel E3 located on the other straight line in the direction opposite to the first direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is determined by the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+(R ×Y3)] (in the above formula, P, Q, and R represent any number from 0 to 1);
A laser recording method comprising: Based on the positional information on the thermal recording medium of the image data to be recorded on the thermal recording medium, the laser light source is directed on the thermal recording medium in one direction in a linear direction and in one direction in a direction perpendicular to the linear direction. or by irradiating the laser beam while moving the thermosensitive recording medium in one direction in a linear direction and in one direction in a direction orthogonal to the linear direction. A laser irradiation program for use in laser recording for recording an image formed by a group of unit pixels that receive color on the thermosensitive recording medium, the program comprising:
When irradiating the laser light onto the heat-sensitive recording medium, control is performed to change the irradiation energy amount of the laser light irradiated from the laser light source according to image brightness information of the image data;
An image brightness value included in one unit pixel data DE0 in the image data corresponding to one unit pixel E0 in the image is X0, and a setting is supplied to the laser light source for recording the image of X0. The amount of current is Y0 (Ah),
First adjacent unit pixel data in the data of the image corresponding to a first adjacent unit pixel E1 located on the opposite side of the one unit pixel E0 in the linear direction and adjacent to the one unit pixel E0. The image brightness value of DE1 is X1, the set amount of current supplied to the laser light source for recording the image of X1 is Y1 (Ah),
Corresponding to the one unit pixel E0, a second adjacent unit pixel E2 located on a straight line and adjacent to the other straight line direction, which is located parallel to and adjacent to the one straight line direction; An image brightness value included in second adjacent unit pixel data DE2 in the image data is X2, and a set amount of current supplied to the laser light source for recording the image of X2 is Y2 (Ah),
The second adjacent unit pixel E2 corresponds to the third adjacent unit pixel E3 located on the other straight line in the direction opposite to the first direction and adjacent to the second adjacent unit pixel E2. The image brightness value included in the third adjacent unit pixel data DE3 in the image data is X3, and the set amount of current supplied to the laser light source for recording the image of X3 is Y3 (Ah),
The amount of current Z (Ah) supplied to the laser light source to actually record the one unit pixel E0 is determined by the following formula, Z=Y0-[(P×Y1)+(Q×Y2)+(R ×Y3)] (wherein P, Q, and R represent any number from 0 to 1),
A laser irradiation program for laser recording, characterized by the following.

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