JP2011235462A - Laser printing method, laser printed matter, and paper container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser printing method that can clearly form a fine code containing a two dimensional code without generating paper powder, and to provide a laser printed matter and a paper container.SOLUTION: The laser printing method includes: a step which forms a black ink layer 4 on a white coat layer 3 on a paper base material 2; and a step which forms a varnish layer 5 on the black ink layer 4. A YVO4 laser beam is irradiated to a request part of the black ink layer 4 and the varnish layer 5. At this point, the parts of the black ink layer 4 and the varnish layer 5 are eliminated to form a printing unit 7, and thereby a laser printed matter 15 is obtained.

Description

  The present invention is used in a laser printing method for laser-printing a fine two-dimensional code on a paper substrate, and packaging of foods, pharmaceuticals, quasi-drugs, and medical instruments, and is obtained by this laser printing method. Laser produced and paper containers.

  2. Description of the Related Art Conventionally, packaging bodies containing contents are distributed in paper containers made from packaging materials including paper base materials. The paper containers of these packages are printed with characters and designs that can be visually confirmed by consumers such as product names, contents, precautions for use, etc. The converted barcode is printed as fixed information of the product.

  Such fixed information can be printed at the manufacturing stage of the packaging material for producing the paper container. On the other hand, fluctuation information that can change daily such as expiry date, lot number, etc. cannot be printed at the manufacturing stage of packaging materials, so thermal printers, inkjet printers, In addition, printing is performed directly on the packaging material of a paper container using a laser printer or the like. Alternatively, a label printed in advance with variable information such as expiration date and lot number that can be changed daily is attached to the packaging material of the paper container or the contents stored in the paper container.

  As such fluctuation information, it was common to print the date of manufacture, lot number, etc. in addition to the expiry date. However, due to the recent increase in public interest in “safety and security”, food, pharmaceuticals, Traceability is required in the field of quasi drugs or medical devices. In order to meet such a demand, the above-described information is printed on the paper container or contents of the package.

  If you try to print the expiry date, date of manufacture, lot number, etc. as the variation information mentioned above, the barcode will be too long, and the length of the barcode may exceed the size of the paper container depending on the paper container. is there. For this reason, for example, a barcode representing a product code and a two-dimensional code representing other variation information are combined using a two-dimensional code including a certain module width that has a higher information density than a barcode and can be made compact in size. , GS1DataBar Limited CC-A, etc., a symbol (code) including a two-dimensional code is used to indicate variation information.

  As a method of printing fixed information and fluctuation information on paper containers, a method of directly printing fluctuation information on packaging materials for paper containers on which fixed information has been printed in advance, or directly printing fluctuation information and fixed information on packaging materials A method to do this has been proposed (Patent Document 1).

  Since the fluctuation information is information that can change from day to day, a thermal printer or an ink jet printer that can easily change print data is often used for printing the fluctuation information. However, consumables such as ink ribbons of thermal printers and inks of ink jet printers are expensive, and there is a problem that running costs are high to print a large amount of variation information. Also, if the expiry date for replacement of these consumables is exceeded, printing failure will occur.

  In addition to thermal printers and ink jet printers, fluctuation information may be printed directly on packaging materials using offset printing using UV curable ink, but depending on dirt on the packaging materials and uneven thickness of the packaging materials, Printing blurring or missing characters may occur. Also, a two-dimensional code having a module width of 0.25 mm or less is too fine to be printed.

  Therefore, attempts have been made to use laser printing that does not require consumables and has excellent printing performance for printing variation information, and so far various inventions for laser printing on packaging materials for paper containers or paper containers have been disclosed. Has been.

  For example, Patent Document 2 discloses a laser printing method in which white ink and black ink are overprinted in this order on a paper base material surface of a packaging material, and the white ink is exposed by removing the black ink layer with laser light. ing.

  However, in order to realize the invention disclosed in Patent Document 2, it is necessary to apply white ink with high concealment on the paper base material of the packaging material. At this time, it is difficult to form a white ink layer with high concealment in offset printing, which is a general printing method for paper substrates. For this reason, as disclosed in Patent Document 2, in the method of removing the black ink layer and exposing the underlying white ink layer, the white ink is not sufficiently concealed and sufficient contrast is obtained. Difficult.

  In addition, when printing with the carbon dioxide laser beam disclosed in Patent Document 2, in order to prevent the white ink layer from being scraped off, the output of the laser beam must be reduced and printing must be performed very slowly over time. It is not practical. In addition, since the carbon dioxide laser beam easily scrapes the white ink layer, the paper substrate may be exposed. In this case, the contrast of the laser printed matter is lowered. For this reason, although the method of printing with a carbon dioxide laser beam can be generally used for printing a barcode, the reading grade is lowered when used for printing a two-dimensional code read with black and white contrast.

  On the other hand, it is widely used considering that fixed information such as producer and product name and various fluctuation information related to manufacturing date, manufacturing date, lot number, and traceability are included in one code in addition to the expiration date. GS1 DataBar Limited CC-A, Data Matrix, QR with a module width of 0.30 mm, 0.25 mm, and a module size of 0.20 mm, which is the smallest size that can be read by a general handy reader. A symbol (code) including a complicated and fine two-dimensional code such as a code (registered trademark) must be used. However, in order to stably read such a two-dimensional code with a barcode reader, it is necessary to improve the contrast of the two-dimensional code laser-printed on the paper container.

  In the conventional method of removing the black ink layer with a laser beam using a carbon dioxide laser beam, all layers such as ivory paper are used as the base paperboard in order to improve the contrast of the two-dimensional code to be laser printed. Paperboard made of white paper may be used. Using such paperboard, even if the surface of the ivory paper is scraped off when the carbon dioxide laser beam removes the black ink layer, only the white cardboard layer of the ivory paper is exposed, so that high contrast can be obtained. it can. Actually, such a method is used for laser printing of numbers such as the date of manufacture of cigarettes in paper boxes, and laser printing of fluctuation information on pharmaceutical sales paper boxes. However, regardless of whether coated or uncoated, low whiteness, undeinked, or unbleached recycled paper such as magazine waste paper or newspaper waste paper is used for the intermediate layer or the back side, so-called coat urajiro, When laser printing is performed with carbon dioxide laser light on coated white balls such as coated uranese and card paper, the white coated layer on the surface layer is scraped, and the recycled paper base material is exposed, and the contrast of the laser printed matter is reduced. .

  By the way, since ivory paper is expensive, it is difficult to use ivory paper for an external box that requires cost reduction, such as a box for a medicine with a low drug price or an external box in which a plurality of products are packaged.

  As described above, carbon dioxide laser is used for laser printing of fluctuation information on coated white balls. However, carbon dioxide laser light is not limited to varnish layers and ink layers on the surface of coated white balls. The white coat layer is also scraped off, and even the paper substrate is easily scraped off. As a result, a large amount of paper dust and smoke are generated and the environment of the packaging process is contaminated. Therefore, it is very difficult to use for printing variation information on a paper box of pharmaceuticals and medical instruments, which emphasizes hygiene.

  In addition, since the laser beam used in conventional laser printing includes a multimode beam in which a peak randomly occurs in the beam, if the output of the carbon dioxide laser beam is reduced so as not to scrape the paper substrate, The black ink layer is left uncut. On the other hand, when the black ink layer is completely removed, there is a problem that the paper substrate is also scraped.

  Further, the coating amount itself of the white coat layer coated on the coated white ball varies greatly, and it is difficult to obtain a good laser print with high contrast.

JP 2007-313876 A Japanese Patent Application Laid-Open No. 10-138641

  The present invention has been made in consideration of such points, and codes including two-dimensional codes such as GS1 DataBar Limited CC-A and QR code (registered trademark) can be clearly laser-printed, resulting in reading errors. An object of the present invention is to provide a laser printing method, a laser printed material, and a paper container that are low in the amount of generation of paper dust and are hygienic.

  The present invention includes a step of forming a black ink layer containing a black pigment on a white coat layer formed on one surface of a paper substrate, a step of forming a varnish layer on the black ink layer, a black ink layer and a varnish layer And a step of irradiating YVO4 laser light to the desired portion of the substrate to remove the portions of the black ink layer and the varnish layer to form a printing portion.

  The present invention is the laser printing method, wherein the varnish layer comprises a mat varnish layer.

  The present invention is directed to laser printing, wherein a desired portion of a black ink layer and a varnish layer is irradiated with YVO4 laser light to remove the black ink layer, thereby forming a two-dimensional code as a printing portion. Is the method.

  The present invention is the laser printing method, wherein the module width of the two-dimensional code is 0.18 mm to 0.33 mm.

  The present invention relates to a paper substrate, a white coat layer formed on one surface of the paper substrate, a black ink layer formed on the white coat layer and containing a black pigment, and a varnish layer formed on the black ink layer And a printed portion is formed by irradiating a desired portion of the black ink layer and the varnish layer with YVO4 laser light to remove the black ink layer and the varnish layer. It is printed matter.

  The present invention is the laser-printed product, wherein the varnish layer is a mat varnish layer.

  The present invention is a laser printed matter characterized in that a desired portion of a black ink layer and a varnish layer is irradiated with YVO4 laser light to remove the portion of the black ink layer, thereby forming a two-dimensional code as a printing portion. It is.

  The present invention is the laser printed product characterized in that the module width of the two-dimensional code is 0.18 mm to 0.33 mm.

  The present invention relates to a paper substrate, a white coat layer formed on one surface of the paper substrate, a black ink layer formed on the white coat layer and containing a black pigment, and a varnish layer formed on the black ink layer And a printed portion is formed by irradiating a desired portion of the black ink layer and the varnish layer with YVO4 laser light to remove the black ink layer and the varnish layer. It is a container.

  The present invention is the paper container, wherein the varnish layer comprises a mat varnish layer.

  The present invention provides a paper container characterized in that a two-dimensional code is formed as a printing portion by irradiating a desired portion of a black ink layer and a varnish layer with YVO4 laser light to remove the portion of the black ink layer. It is.

  The present invention is a paper container characterized in that the module width of the two-dimensional code is 0.18 mm to 0.33 mm.

  According to the present invention, it is possible to obtain a laser printed matter and a paper container on which fine codes such as a two-dimensional code are clearly printed while suppressing the generation of paper dust.

  Further, when the varnish is a matt varnish, laser printed matter and a paper container containing a two-dimensional code can be obtained with fewer reading errors.

  As described above, according to the present invention, it is possible to obtain a laser printed matter and a paper container on which fine codes such as a two-dimensional code are clearly printed while suppressing generation of paper dust.

FIG. 1 is an explanatory diagram for carrying out a laser printing method according to the present invention. FIG. 2 is a view showing a laser print according to the present invention. FIG. 3 is a view showing a laser print obtained by a conventional laser printing method. FIG. 4 is a view showing a laser printing part obtained by a conventional laser printing method. FIG. 5 is a view showing a paper container having a printing unit according to the present invention. FIG. 6 is a view showing another paper container having a printing unit according to the present invention. FIG. 7 is an enlarged view showing a two-dimensional code.

  Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 2 and FIGS. 5 to 7 are diagrams showing a laser printing method, a laser printed material, and a paper container according to the present invention.

  First, referring to FIG. 2, the laser printed matter 15 obtained by the laser printing method of the present invention will be described.

  As shown in FIG. 2, the laser printed material 15 includes a paper base material 2, a white coat layer 3 formed on one surface of the paper base material 2, a black ink layer 4 formed on the white coat layer 3 and containing a black pigment, And a varnish layer 5 formed on the black ink layer 4.

  The desired portions of the black ink layer 4 and the varnish layer 5 are irradiated with YVO4 laser light, so that the portions of the black ink layer 4 and the varnish layer 5 are removed, thereby forming the printing unit 7 (FIG. 2).

  The laser printed matter 15 having such a configuration constitutes a packaging material for producing a paper container 20 described later, for example. That is, a paper container 20 is obtained by using a packaging material made of the laser-printed material 15 as a punching blank and assembling the blank (FIGS. 5 and 6).

  The two-dimensional code 11 appearing on the surface of the paper container 20 can be formed by the printed matter 7 of the laser printed matter 15. In addition to the two-dimensional code 11, the product name printing unit 10 and the barcode 12 can be formed on the surface of the paper container 20. And the character part 13 are displayed (FIGS. 5 and 6).

  In addition, the design printing part 10, bar code 12, and character part 13 other than the two-dimensional code 11 may be formed by the printed matter 7 of the laser printed matter 15, or may be printed by a method other than the laser printing method.

  The two-dimensional code 11 formed by the printed matter 7 of the laser printed matter 15 has a basic cell width (cell width) 1 as shown in FIG. Although not particularly illustrated, the minimum bar width of the bar code is referred to as a module width, and the module width and cell width of a composite code in which a two-dimensional code and a bar code are combined are equal, and are generally expressed as a module width.

  1 and 2, the coated white ball 1 is composed of the paper base material 2 and the white coat layer 3 on the paper base material 2, and the printing ink layer 6 is composed of the black ink layer 4 and the varnish layer 5. Is done.

<Production of coated white balls for laser printing>
Next, the laser printing method according to the present invention will be described.

  First, a coated white ball for laser printing is produced.

  That is, as shown in FIG. 1, first, a paper base 2 is prepared, and a white coat layer 3 is formed on one surface of the paper base 2 to obtain a coated white ball 1.

  The coated white ball 1 is composed of a white paper base 2 such as a cardboard made by unbleached recycled paper, unbleached recycled paper, or the like, and a white paper layer made by bleaching or unbleached white paper layer, and a paper base 2 A paperboard having a white coat layer 3 obtained by coating a white pigment on the top and improving surface smoothness and whiteness. The one where the recycled paper layer is exposed on the opposite side of the white coat layer 3 is called Coat Uranez, and the one obtained by laminating white paper such as bleached paper on the recycled paper layer on the opposite side of the white coat layer 3 is called Coat Urado. There is also a coated white ball 1 colored on the recycled paper layer.

  The white coat layer 3 is coated with a mixture of a white pigment and an adhesive on the paper substrate 2 to improve surface smoothness and to perform a calendar process through a calender roll for the purpose of hardening the adhesive. As a result, it is formed on the paper substrate 2.

  The surface of the cardboard used as the paper substrate 2 has pulp fiber irregularities, and even if the white coat layer 3 is formed on the surface, microscopically some irregularities due to the white pigment particles and the pulp fibers Unevenness such as undulation caused by the remains.

  The coated white ball 1 is generally called a coated varillo or a coated uranez, a cardboard having a layer made of undeinked or unbleached newspaper waste and / or magazine waste paper, or Since it is made from undeinked or unbleached recycled paper pulp, it is made of cardboard having a recycled paper substrate 2 dyed to conceal color unevenness. The surface of the recycled paper base 2 is provided with a layer whose whiteness is increased in advance by laminating and making a white paper layer such as a deinked recycled paper layer or a high-quality waste paper bleaching layer. By forming the white coat layer 3 on the surface of the material 2, a coated white ball 1 having high whiteness and excellent surface smoothness can be obtained even when recycled paper such as undeinked newspaper wastepaper is used.

  The most common main component of the white pigment of the white coat layer 3 is clay (including various modified clays such as calcined clay and chemically modified clay), and other inorganic pigments include heavy calcium carbonate, light calcium carbonate, There are titanium dioxide, aluminum hydroxide, silica, satin white, talc, etc., and organic pigments such as pigments made of polystyrene or polyacrylic resins, urea resin pigments, etc. can be used alone or these pigments A plurality of types are used in combination.

  As the adhesive, various modified starches, polyvinyl alcohol, casein and the like can be used alone or in combination.

  If necessary, as other auxiliary agents, a dispersant, a pH adjuster, an antifoaming agent, a release agent, etc. may be used alone or in combination.

  As described above, many kinds of pigments exist as the white pigment of the white coat layer 3 on the surface of the coated white ball 1, but the laser printing method of the present invention uses laser light that is not easily absorbed in white, There is no need to limit the types of court white balls.

<Formation of printing ink layer for laser printing>
Next, the black ink layer 4 is formed on the white coat layer 3, and then the varnish layer 5 is formed on the black ink layer 4. Thus, the printing ink layer 6 is formed by the black ink layer 4 and the varnish layer 5. can get. Since the printing ink layer 6 for laser printing composed of the black ink layer 4 and the varnish layer 5 is provided, printing is performed on the coated white ball 1. As such printing methods, offset printing, gravure printing, flexographic printing, silk Any method such as screen printing may be used. Of these, sheet-fed offset printing is generally used.

  What is important in the present invention is not a printing method, and any printing method includes at least a black ink layer 4 made of a black pigment such as carbon or titanium black as the printing ink layer 6 for laser printing. By applying a varnish to the surface, the varnish layer 5 is formed to impart wear resistance.

  When the black ink layer 4 is provided on the coated white ball 1, it becomes noticeable when pinholes are generated in the black ink layer 4, and therefore, as a base layer of the black ink layer 4, other colors are often used to make the pinholes inconspicuous. Or black ink is expressed by overprinting yellow, indigo and red. In the present invention, since laser light for removing the black ink layer 4 is used as will be described later, use of ink other than black ink leaves color ink other than black in the printing unit 7 and lowers contrast, which is not preferable. . However, when a symbol is read with the light of the red LED, red, pink, and yellow may be superimposed.

  A varnish layer 5 is formed on the surface of the coated white ball 1 to protect the black ink layer 4. In the printing ink layer 6 for laser printing according to the present invention, the varnish layer 5 formed on the surface of the black ink layer 4 may be either a gloss varnish layer or a mat varnish layer.

  In the present invention, when the printing unit 7 is mechanically read, it is preferable that a mat varnish layer is used since the light emitted from the machine is hardly reflected to the reading unit when the machine reads. A mat varnish layer may be formed only in the vicinity of the printing unit 7 and a gloss varnish layer may be formed in other portions. When the mat varnish layer is formed, a medium ink or an ink obtained by adding a matting agent to gloss varnish is used.

<Laser irradiation>
Next, YVO4 laser light is irradiated to the desired portions of the black ink layer 4 and the varnish layer 5, and the portions of the black ink layer 4 and the varnish layer 5 are removed to form the printing portion 7 (FIG. 2).

  The laser beam used in the present invention is a single mode YVO4 laser beam. Single-mode laser light is laser light having a single peak and is suitable for fine processing because the focus is reduced.

  The YVO4 laser is a kind of YAG laser, and the wavelength of the laser beam is 1064 nm, and it is difficult to be absorbed by colors other than black. However, since the YVO4 laser is not totally reflected, even if it is white, for example, if a strong output is given to organic matter, scorching will occur first, and the carbon black in the generated scoring part will absorb the laser light. Laser printing can also be performed. However, it takes a long time for printing and the printing accuracy is lowered, which is not preferable.

<Laser printing conditions>
The most important conditions for laser printing are output, scanning speed, and pulse frequency, but the laser output device capability, printing area, black ink material, required printing time, required symbol grade, etc. Since the laser printing conditions differ depending on the range, the range cannot be specifically limited.

  When it is desired to increase the laser printing speed, the output is increased to increase the scanning speed. However, if the scanning speed is too high, the scanning accuracy is lowered and the printed product is not finished.

  When it is desired to improve the finish of the laser print, it is preferable to reduce the output and reduce the scanning speed, but the printing time becomes longer.

  The pulse frequency varies depending on the black pigment material of the black ink layer 4 so that ink can be removed most effectively. In general, the pulse frequency is not a numerical value that fluctuates so much, so when determining the laser printing conditions, an appropriate frequency is initially set.

  In selecting the laser printing conditions, the laser printing test is performed by trying several combinations of output and scanning speed while verifying the symbol of the laser printed matter with a verification machine. The laser print is verified by trying laser printing with a fixed output and scanning speed and changing the frequency in several ways. Finally, fine adjustment of output and scanning speed is performed to select the most suitable laser printing conditions.

  In determining suitable laser printing conditions, the most important factor is contrast, and most laser print grades depend on the contrast grade. The high contrast situation in which there is no or little black ink residue in the laser printing area and the coated layer of the coated white ball is scraped off and the recycled paper layer of the cardboard is not exposed can be judged visually. .

  FIG. 2 shows a laser print 15 obtained using the laser printing method of the present invention. In FIG. 2, the laser beam (single mode YVO4 laser beam) output / scanning speed is adjusted, and the laser beam is irradiated while controlling the position in accordance with the print pattern such as characters and designs. As a result, the varnish layer 5 is burned and removed together with the black ink layer 4 where the laser beam is irradiated, and when the laser beam reaches the white coat layer 3, most of the laser beam is reflected and the white coat layer is reflected. 3 is hardly removed.

  Such a phenomenon is also apparent from the amount of printing residue generated in the laser-printed portion. After removing foreign matter on the varnish layer 5 of the printing ink layer 6 with a weak adhesive tape in advance, the laser printing method of the present invention is used. Laser printing is performed to form the printing unit 7. Next, a weak adhesive tape was again applied in the vicinity of the printing unit 7 and peeled off. In this case, almost no visible foreign matter can be recognized on the adhesive surface of the weak adhesive tape, and even when the surface of the laser-printed product 15 of the present invention is rubbed with a finger, a portion where the black ink is removed and a portion where the black ink is not removed. I can't feel the difference.

  On the other hand, in the case of the laser printed matter 15 using the conventional carbon dioxide laser beam, the level difference between the printing portion 7 and its periphery is large, and a rough feel can be confirmed by rubbing with a finger. In addition, visible foreign matter can easily confirm paper dust, burned residue of paper dust, a peeled coat layer, and the like.

  In the laser printed matter 15 according to the present invention obtained as described above, a high contrast between the black ink layer 4 and the white coat layer 3 can be obtained, and a symbol contrast value (bar) is one of the verification items of the barcode. A difference between the maximum reflectance and the minimum reflectance on the cord) of 55% or more can be easily obtained. Therefore, B can be easily obtained with a symbol contrast grade.

  At this time, when the varnish layer 5 is composed of a gloss varnish layer, the gloss varnish layer 5 on the surface of the black ink layer 4 may reflect the light of the measuring instrument, and the minimum reflectance of the black ink layer 4 may be increased. In such a case, the symbol contrast value decreases to 40% to less than 55%, but it does not interfere with barcode reading. Further, depending on the incident angle and reflection angle of the measurement light, the same laser print may have a symbol contrast value of less than 20%, but it can be read.

Next, referring to FIG. 3 and FIG. 4, a laser printed matter 15 as a comparative example using a conventional carbon dioxide laser will be described. FIG. 3 is a diagram showing a laser printed product 15 that is laser-printed using a conventional carbon dioxide laser so as to keep the recycled paper layer of the coated white ball 1 from being exposed in order to keep the generation of printing waste as low as possible.
As shown in FIG. 3, since the carbon dioxide laser light removes the white coat layer 3, if the printing unit 7 is formed by laser printing with a weak output so as not to expose the recycled paper layer of the cardboard, the printing is inevitably performed. The black ink layer 4 partially remains in the portion 7, and the symbol contrast value in the printing portion 7 is lowered. In addition, since the white coat layer 3 is also partially removed, a lot of fine print residue adheres to the surface of the laser print 15 after printing. Moreover, since the black ink layer 4 remains in the printing part 7 formed by laser printing, a reading error is likely to occur. Furthermore, since there are a plurality of fine peaks in the carbon dioxide laser beam, it is difficult to perform precise drawing in a short time. For this reason, when a barcode or two-dimensional code having a module width of 0.33 mm or less is formed by a laser printing method, it is difficult to obtain a readable barcode or two-dimensional code.

  FIG. 4 is a view showing a laser printed product 15 that is laser-printed under the condition that the black ink layer 4 is completely removed using a conventional carbon dioxide laser so that the black ink layer 4 is not removed. In FIG. 4, since the white coat layer 3 is also partially removed, the cardboard (paper base material) 2 is exposed. Even with such a laser-printed matter 15, if the coated white ball has a high degree of whiteness, such as ivory paper, a high-contrast laser-printed product can be obtained as long as the cardboard does not burn with laser light. However, in a coated white ball using a cardboard containing a layer made of undeinked or unbleached waste paper, the undeinked layer or the unbleached layer is exposed, and the symbol contrast value decreases, It will be 40% or less. For this reason, it is sufficient that the printed content is read by humans, such as characters, but the grade is lowered with a barcode or two-dimensional symbol read by a machine. In particular, it is not preferable to use a carbon dioxide laser in a pharmaceutical paper container that is required to have grade C or higher in comprehensive judgment in view of variations in the thickness of the white coat layer 3.

  Next, a paper container 20 made of the laser print 15 according to the present invention will be described with reference to FIGS.

  As shown in FIG. 5, the surface of the paper container 20 is obtained by laser printing together with the product name printed in advance by an offset printing machine or the like, the product name printing unit 10 such as the internal capacity, the barcode 12 and the character unit 13. The two-dimensional code 11 is displayed. In FIG. 5, laser printing is performed after the paper container 20 is assembled. However, laser printing may be performed in a blank or sack-attached state immediately before the paper container 20 is assembled. In FIG. 5, the two-dimensional code 11 is formed on the display unit 11 for laser printing on the surface of the paper container 20.

  In the paper container 20 shown in FIG. 6, the surface of the paper container 20 includes a two-dimensional code such as a product name printing unit 10 such as a product name and content, a character unit 13, a numeric unit 14, and GS1 DataBar Limited CC-A. A bar code 12 is provided, and the product name printing unit 10, the character unit 13, the number unit 14 and the bar code 12 are all configured by the printing unit 7 formed by the laser printing method according to the present invention.

  EXAMPLES Next, although an Example is given and this invention is demonstrated concretely, these Examples do not restrict | limit this invention at all.

Example 1
Using coated white balls 1 (product name “UF Coat” manufactured by Oji Paper Co., Ltd.) containing a paper base 2 with a basis weight of 310 g / m ² as coated uranes with the reverse side being undeinked recycled paper, A product name printing unit 10 such as a design printing unit was formed on the white coat layer 3 of the coated white ball 1 using a leaf offset UV printing machine. At the same time, after forming the laser printing display portion 11A including the black ink layer 4 of 20 mm × 35 mm using the black ink, the UV medium ink is applied to the entire surface of the coated white ball 1 excluding the paste margin portion, and the varnish layer 5 After forming, punching and sack pasting were performed. Thereafter, the black ink layer 4 and the varnish layer 5 were irradiated with YVO4 laser light to produce a laser printed matter 15. Then, the said sack pasted product was assembled and the paper container 20 of length 76mm x width 110mm x height 62mm was obtained. The printing unit 7 of the paper container 20 is located at the lower right of the top surface of the paper container 20.

(Example 2)
Laser printed material 15 was manufactured in the same manner as in Example 1. In this case, in the laser printed matter 15, UV gloss varnish was applied to the entire surface of the paper box forming portion excluding the glue margin, punched out, and sack pasted. By assembling the sack-attached product, a paper container 20 having a length of 76 mm, a width of 110 mm, and a height of 62 mm was obtained as in Example 1. The printing unit 7 of the paper container 20 is located at the lower right of the top surface of the paper container 20.

(Laser printing conditions)
In Example 1 and 2, in order to obtain the laser printed matter 15, a single mode beam YVO4 laser printer (trade name “MD-V9900” manufactured by Keyence Corporation) is used for the black ink layer 4 and the varnish layer 5. , YVO4 laser light was irradiated. In this case, the black ink layer 4 of the printing unit 7 was invisible with the naked eye, and the lowest laser power condition was visually compared. At the same time, the scan speed is fixed at 1000 mm / second, the laser power and frequency are changed, and the GS1 DataBar Limited CC, which is a composite code composed of a barcode (RSS limited) and a two-dimensional code (CCA) with a module width of 0.33 mm. -A laser printing test was performed. As a result, the conditions of a laser power of 70% and a frequency of 40 kHz were the most excellent.

  In Examples 1 and 2, GS1 DataBar Limited CC-A is used for the convenience of evaluating both a barcode and a two-dimensional code at one time. A symbol to be laser-printed based on the present invention is a barcode, Even if the two-dimensional code is another standard, there is no problem.

  In this example, the GS1 DataBar Limited CC-A, which the Ministry of Health, Labor and Welfare required to print on a pharmaceutical package derived from a specific organism, was formed with YVO4 laser light. However, the laser printing method of the present invention is limited to the printing of the symbol. Instead, symbols including other two-dimensional codes such as Data Matrix and QR code (registered trademark) may be formed.

(Laser print comparison experiment)
Similarly, in Comparative Experiments 1 and 2, a carbon dioxide laser printer (trade name “ML-Z9500”, manufactured by Keyence Corporation) is used for the black ink layer 4 and the varnish layer 5 in order to obtain the laser printed matter 15. The carbon dioxide laser beam was irradiated. In this case, the scan speed was fixed at 1000 mm / second while visually comparing and judging the lowest laser power condition where the black ink layer 7 of the printing unit 7 became invisible with the naked eye. Since the frequency cannot be changed due to the function of the apparatus, a laser printing test of a GS1 DataBar Limited CC-A having a module width of 0.33 mm was performed by changing the laser power. As a result, the laser power of 90% was the best. Comparative experiment 1 is the same as that of Example 1 except that carbon dioxide laser light was used instead of YVO4 laser light. Comparative experiment 2 is the same as Example 2 except that carbon dioxide laser light was used instead of YVO4 laser light.

(Manufacture of laser prints)
Under the respective laser printing conditions obtained by the two apparatuses, in Examples 1 and 2 and Comparative Experiments 1 and 2, the module width l is 3 of 0.33 mm, 0.25 mm, 0.20 mm, and 0.18 mm. One kind of GS1 DataBar Limited CC-A was formed at one place of the display unit 11 for laser printing to produce a laser printed product 15, and 10 laser printed products 15 were produced.

  As a result, in Examples 1 and 2, the laser-printed product 15 using the YVO4 laser beam exhibited the white color of the white coat layer 3 with a clean printed portion, and smoke was generated during laser printing, but the print residue on the laser-printed product 15 was printed. Was not recognized with the naked eye, and even when the printed part was wiped with the fingertip, no dirt was adhered to the finger, and no step was felt between the printed part and the non-printed part.

  However, in Comparative Experiments 1 and 2, the laser-printed matter 15 by the carbon dioxide laser beam exhibits the grayish white color of the recycled paper in the printing unit 7, and not only clearly the contrast is lowered, but also the powder of the coating layer and the paper Printing waste such as powder was scattered around and was not in a hygienic state. Further, the laser printed matter 15 having a module width l of 0.20 mm or less had almost all the black ink layer 4 to be left removed, and it was found that the level was unreadable by the naked eye.

  From this, the laser-printed matter 15 and the paper container 20 created by the laser printing method according to the present invention are more hygienic than the laser-printed matter 15 and the paper container 20 created by the conventional laser printing method. Is suitable.

(Verification of print quality)
The printing quality of Examples 1 and 2 and the laser print 15 of the comparative experiment was verified using a verification machine (trade name “TC401-RL”, manufactured by Munazo Co., Ltd.). The verification grade at this time is shown in Table 1.

  The verification grade here is defined by the American standard ANSI X3.182. For example, element edge judgment, etc., 8 barcodes and composite codes, and 2 evaluation codes are measured with 17 evaluation items. The respective measurement results are expressed in five stages of A, B, C, D, and F. The verification grade is a measurement item grade indicating the lowest evaluation grade among all the evaluation results, and represents the grade of the symbol to be measured.

Incidentally, A is the highest grade, D is the lowest grade, and F represents a defect. However, grade F can be read by a normal handy reader or inspection device, but if it is not regarded as a symbol, evaluation of grade F cannot be obtained. In general, since the use of grade C or higher is recommended, it is often managed with quality of grade B or higher in consideration of the sudden drop in grade due to variations in printing quality.

  As shown in Table 1, in Examples 1 and 2, the symbol (printing unit 7) formed by laser printing on the laser printing display unit 11A using the single mode beam YVO4 laser beam has high contrast and precision printing. All have grade B due to the effect of However, in the symbol laser-printed on the laser printing display portion 11A of Example 2, the measurement light of the verification machine may be reflected on the gloss varnish, but grade B can be obtained by measuring the position slightly shifted in the verification machine. Therefore, it was judged to be substantially grade B. Needless to say, all readings by a handy reader (trade name “BT-951”, manufactured by Keyence Corporation) could be performed accurately.

  On the other hand, in Comparative Experiments 1 and 2, the symbol (printing portion 7) formed by laser printing on the laser printing display portion 11A using carbon dioxide laser light is a laser printed product having a module width l of 0.33 mm. No. 15 was grade C due to a decrease in contrast due to partial exposure of the recycled paper layer at the printing unit 7. In the printing part 7 of the laser printed matter 15 having a module width l of 0.25 mm, the periphery of the scanning laser beam is also cut widely, and the module width becomes abnormally thin due to the phenomenon that the module width is thinned and becomes grade F. .

  Furthermore, in the laser printed matter 15 with the module width l of 0.20 mm and 0.18 mm, the ratio of the module width l is increased, and the verification machine cannot recognize the symbol, so that it can be read by a handy reader. There wasn't.

  From the above results, it is clear that the laser printing method of the present invention can obtain a fine printed matter with higher accuracy than the conventional method.

(Manufacture of paper container 20)
Using a YVO4 laser printer and a carbon dioxide laser printer, a paper container 20 was prepared from the laser printed matter 15 according to Examples 1 and 2 on which GS1 DataBar Limited CC-A having a module width l of 0.33 mm was printed. Thus, a paper container 20 was produced from the laser printed material 15 according to the comparative example. In each of the ten paper containers 20 produced in Examples 1 and 2, five commercially available eye drops were collected together in a box, and then shrink-wrapped using a polypropylene shrink film.

  In Examples 1 and 2, laser printing was performed on the sack-attached laser printed material 15 of the paper container 20, but after forming the paper container 20 or storing the contents in the paper container 20, the laser was printed. Printing may be performed.

  As a result of opening the package and taking out the contents and observing the foreign matter adhering to the outer surface of the shrink film with the naked eye, in Examples 1 and 2, the contents of the paper container 20 laser-printed using a YVO4 laser printer were used. The number of adhering foreign matter was several per box at most, which seemed to be paper dust.

  On the other hand, in the comparative example, the contents in the paper container 20 laser-printed using the carbon dioxide laser printer are not only foreign substances that seem to be paper dust, but also black foreign substances in which laser-printed residue has entered the inner surface of the paper container 20. Was seen. There were three boxes in which ten or more black foreign matters made of such laser-printed residue adhered. Although the size of the black foreign substance is about one tenth of that of paper dust, it looks very dirty compared to whitish paper dust, so it is very disliked in the packaging of pharmaceuticals, medical devices, cosmetics and the like.

  From the above results, the paper container 20 made of the laser printed material 15 created by the laser printing method according to the present invention is more hygienic than the paper container 20 made of the laser printed material 15 made by the conventional laser printing method, and stores the medicine. It is clear that it is suitable for paper boxes that do.

DESCRIPTION OF SYMBOLS 1 Coat white ball 2 Paper base material 3 White coat layer 4 Black ink layer 5 Varnish layer 6 Printing ink layer 7 Printing part 10 Design printing part 11A Laser printing display part 11 Two-dimensional code 12 Bar code 13 Character part 14 Number part 15 Laser printing unit 20 Paper container

Claims (12)

Forming a black ink layer containing a black pigment on a white coat layer formed on one surface of a paper substrate; and
Forming a varnish layer on the black ink layer;
Irradiating YVO4 laser light to desired portions of the black ink layer and the varnish layer to remove the portions of the black ink layer and the varnish layer to form a printing portion, and laser printing, Method.   The laser printing method according to claim 1, wherein the varnish layer comprises a mat varnish layer.   2. The laser according to claim 1, wherein a two-dimensional code is formed as a printing portion by irradiating a desired portion of the black ink layer and the varnish layer with YVO4 laser light to remove the portion of the black ink layer. Printing method.   The laser printing method according to claim 3, wherein the module width of the two-dimensional code is 0.18 mm to 0.33 mm. A paper substrate;
A white coat layer formed on one side of the paper substrate;
A black ink layer formed on the white coat layer and containing a black pigment;
A varnish layer formed on the black ink layer,
A laser-printed product, wherein a printing portion is formed by irradiating YVO4 laser light to desired portions of a black ink layer and a varnish layer to remove the portions of the black ink layer and the varnish layer.   6. The laser printed product according to claim 5, wherein the varnish layer comprises a mat varnish layer.   6. The laser according to claim 5, wherein a two-dimensional code is formed as a printing portion by irradiating a desired portion of the black ink layer and the varnish layer with YVO4 laser light to remove the portion of the black ink layer. Printed matter.   6. The laser printed matter according to claim 5, wherein the module width of the two-dimensional code is 0.18 mm to 0.33 mm. A paper substrate;
A white coat layer formed on one side of the paper substrate;
A black ink layer formed on the white coat layer and containing a black pigment;
A varnish layer formed on the black ink layer,
A paper container, wherein a printing portion is formed by irradiating a desired portion of a black ink layer and a varnish layer with YVO4 laser light to remove the black ink layer and the varnish layer.   A paper container, wherein the varnish layer comprises a mat varnish layer.   A paper container for forming a two-dimensional code as a printing portion by irradiating a desired portion of a black ink layer and a varnish layer with YVO4 laser light and removing the portion of the black ink layer.   A paper container characterized in that the module width of the two-dimensional code is 0.18 mm to 0.33 mm.

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