JP6117523B2 - Method for producing printing film - Google Patents

Description

  The present invention relates to a method for producing a printed film, and more specifically, a printing unit surface formed by multicolor printing is arranged on one surface of a long plastic film along the longitudinal direction of the film. The present invention relates to a method for producing a printed film.

  Conventionally, for the purpose of content display, advertisement, and improvement of product value, the outer surface of metal cans (label cans) such as seamless cans and welded cans has a film that has been designed with gravure printing on a transparent resin film. It is stuck. Such a film is generally formed by continuously forming a printing unit surface by multicolor printing on one surface of a long plastic film, and the printed long film is appropriately coated with an adhesive. It is wound and stored on a roller, and is unwound from the roller at the time of use.

  By the way, in recent years, printing has become more multicolored due to diversification of design, etc., the number of colors of ink used in gravure printing has increased, and the number of printing according to the number of colors is required. Causes unevenness in the thickness of the printed layer, causing an unexpected inconvenience. For example, a long printed film used for a label can as described above may generate linear protrusions called bones due to uneven thickness of ink when wound on a roller. In particular, recently, the thickness of the film has been reduced from the standpoint of cost reduction and the tension at the time of winding around the roller has been set from the viewpoint of increasing the production speed, and the occurrence of bone is frequently observed. It is becoming. Such bone formation induces peeling of the ink layer and peeling of the adhesive (blocking) when the printed film wound around the roller is unwound from the roller, and eventually wrinkles when wound around the can body. Will cause poor appearance.

As a means for correcting the thickness unevenness of the printing layer, for example, Patent Document 1 discloses a colorless and transparent so as to have a thickness equivalent to the printing ink layer on a plain portion other than the printing portion of the printed film base. It has been proposed to apply a resin.
Patent Document 2 proposes that in a gravure printing method for printing a pattern on a plastic film, a transparent ink or the like is applied to a non-pattern part so that the film thickness of the ink or the like is uniform over the entire surface. Has been.

Japanese Patent Publication No.58-52814 JP 2009-255436 A

  As proposed in Patent Documents 1 and 2, a method of applying an ink or resin to a thin portion to make the entire thickness uniform has been conventionally employed. However, such means are effective when the print design is simple and the number of inks used is small, but it is practically impossible when the number of inks is large and a complicated print design is applied. It can be said. That is, for example, when a print design is formed with only two colors of white ink and black ink, and the black ink layer is formed on the white ink layer, the portion other than the black ink layer is formed. It is only necessary to apply a resin or ink that adjusts the thickness (hereinafter referred to as correction ink), but as the number of inks increases and the print design becomes more complicated, it becomes difficult to define a portion to which correction ink is applied. End up. Even if the portion to be subjected to the correction ink can be determined, the portion has a complicated shape, and it is extremely difficult to apply the correction ink to the portion with high accuracy. In addition, the above-described linear convex portions called bones are also induced when the portion to which the correction ink is applied is slightly shifted.

  As described above, in multicolor printing using a large number of color inks, it is extremely difficult to adjust the thickness of the formed printing layer uniformly, and the effectiveness is poor. Therefore, depending on the experience and intuition of engineers, the location where bones are likely to occur is selected according to the printing design, and correction ink is applied to this part. Because of this, it is necessary to test print the film over thousands of meters in length to check for the occurrence of bone, and in some cases, the very long film must be discarded, and the bone is generated In some cases, the plate (bone plate) for applying the correction ink had to be corrected, and a great deal of cost and time were spent to prevent bone.

Accordingly, an object of the present invention is a long printing film having a printing layer by multicolor printing on one surface, and linear protrusions resulting from uneven thickness of the printing layer when wound on a roller An object of the present invention is to provide a method for producing a printed film in which occurrence of (bone) is effectively prevented.
The present applicant has previously proposed a method for producing a printed film in which the generation of bone as described above is effectively prevented (Japanese Patent Application No. 2011-132267). Even if compared with this, it aims at preventing generation | occurrence | production of a bone more reliably.

According to the present invention, there is provided a printing film in which a printing unit surface formed by a multicolor printing layer composed of an ink layer of each color is arranged on one surface of a long plastic film along the longitudinal direction of the film. In the manufacturing method,
Prepare plate making data created for each color ink forming the multicolor printing layer,
Based on the plate making data, for each divided area of the printing unit surface having a constant width w perpendicular to the printing direction, a single color total gradation value corresponding to the ink amount is obtained by image processing for each of the inks of each color. Calculate
Based on the calculated value, for each of the divided areas, a provisional graph showing the total color total gradation value corresponding to the total ink amount of the inks of the respective colors is created over the entire printing unit surface,
The correction ink is applied to the divided area where at least the total color total gradation value is insufficient so that the total color total gradation value in each divided area is 60 to 100% of the maximum value of the total color total gradation value. Create a correction graph by adding the total gradation value of
Based on the correction graph, create bone plate data for the correction ink,
Using a plate roller for each color ink created based on the plate-making data and a bone plate roller made based on the bone plate data, an ink for each color ink is applied to one surface of the long plastic film. Winding on a roller while continuously performing printing with a correction ink and printing with a correction ink,
The manufacturing method of the printing film characterized by these is provided.

  In the present invention, it is preferable that the width w of the divided region is set by equally dividing the width in the direction perpendicular to the printing direction of the printing unit surface into a large number of 1000 or more.

Further, in the present invention, the stencil provisional data (also referred to as provisional correction data) in which the application position and the application amount of the primary correction ink for rough thickness correction are set together with the plate making data of each color ink. Can also create bone version data, for example,
Along with the plate-making data of each color ink, prepare temporary stencil data prepared for the primary correction ink applied to the portion where the thickness of the multicolor printing layer is small,
For the printing unit surface, for each divided area having the constant width w, based on the plate-making data for each color ink, the single color total gradation value is calculated for each color ink, and at the same time based on the bone temporary data Calculating the total gradation value for the primary correction ink by image processing,
In the temporary graph, the total gradation values for the primary correction ink are stacked in each divided area.
The correction graph is created by adding a gradation value for the secondary correction ink to a divided area where the total ink amount is insufficient.
Based on the correction graph, the stencil temporary data is corrected, and stencil data for correction ink obtained by adding secondary correction ink to the primary correction ink is created.
The following means can be adopted.

  Furthermore, the stencil provisional data as described above is a rough one in which a correction ink layer (primary correction ink layer) is formed in a portion where the thickness of the multicolor printing layer is small. For example, for each color ink, A processed image obtained by binarizing the thickness of the multicolor printing layer can be formed on the printing unit surface based on the prepared plate making data, and temporary bone data can be generated based on the processed image. .

  In the present invention, predetermined plate-making data formed for each color ink forming a multicolor printed image, and correction for correcting the thickness of the multicolor print layer formed based on each color ink The bone plate data for forming the ink layer is used, and based on these data, a plate roller for each color ink and correction ink is produced and printed on a long film. In particular, since the bone plate data is created based on the visualized data (graph), the bone plate data can be created easily in a remarkably short time.

In addition, the visualized data (graph) for creating the stencil data is obtained by stacking the number of pixels corresponding to the ink amount of each color in each divided area having a constant width w perpendicular to the printing direction on the printing unit surface. Based on the provisional graph, it is created by adding the number of pixels for the correction ink to an area having a small total number of pixels. For this reason, the total ink amount (that is, the thickness of the ink layer) can be set within a certain range over the entire width direction of the printing unit surface. That is, the print unit surface is finely divided in the width direction (for example, 1000 divisions or more), and the width w of the divided region is set to be small and fine, so that the number of pixels corresponding to the total ink amount can be increased or decreased even for fine portions. Therefore, the stencil data is used to determine the application amount and position of the correction ink so that the total ink amount is within a certain range over the entire width direction of the printing unit surface. Can be set with high accuracy.
As a result, in the present invention, it is possible to reliably prevent the occurrence of bone caused by the presence of a large amount of ink locally.

  In addition, the creation of bone data as described above can be performed easily and in a short time by processing using commercially available image processing software and spreadsheet software, without relying on experience or intuition, Even when a complicated design is applied by multicolor printing, a long printing form can be wound around a roller without generating bone, and the product quality can be greatly improved.

The schematic diagram which shows an example of the cross-sectional structure in the printing unit surface of the multicolor printing film in which the thickness adjustment by correction | amendment ink is not performed. The schematic plan view of the printing film of FIG. The figure which shows the state which wound up the multicolor printing film of FIG. 1 on the roller. The schematic diagram which shows an example of the cross-sectional structure in the printing unit surface of the multicolor printing film by which thickness adjustment by the correction | amendment ink was performed according to this invention. The figure which shows the state which wound up the printing film of FIG. 4 on the roller. The figure for demonstrating the division area formed in a printing unit surface. The figure which shows the temporary graph which shows the all color total gradation value of the ink of each color for every division area. The figure which shows the correction graph which corrected the temporary graph of FIG. 7 with the correction ink.

  1 and 2, when a print design is formed on one side of a film by multicolor printing, a long film 1 is used, which is fed from a roller (not shown), and the film 1 By continuously performing multicolor printing by gravure printing on one of the surfaces, the printing unit surfaces (designated as 3 as a whole) on which the printing design has been performed are continuously arranged along the film feeding direction. After completion of such printing, an adhesive is applied onto the printing unit surface 3, and the formed printing film is wound around a roller (not shown). The printing unit surfaces 3 formed by gravure printing may be formed in a single row or may be formed in a plurality of rows. FIG. 2 shows an example in which the printing unit surfaces are formed in two rows.

  As shown in FIG. 1, the printing unit surface 3 formed on the long film 1 has a form in which the printing design is observed from the front surface A side of the film 1, and the back surface B of the film 1. On the side, a multicolor printing layer 5 indicated by 5 as a whole is formed. That is, the multicolor printing layer 5 is formed from ink layers 5a to 5f of each color, for example, color ink layers 5a, 5b, 5c, and 5d such as black, purple, red, and yellow are formed, and further, metallic A bright ink layer 5e for expressing a feeling and a white ink layer 5f serving as a background are formed, and a desired print design is formed by these ink layers.

  However, in such a printing unit surface, depending on the printing design, the color development on the surface A side differs depending on the position. For example, in some portions, there is a portion where all of the ink layers 5a to 5f overlap, There is also a portion where only the white ink layer 5f exists. For this reason, unevenness is formed on the surface of the printing unit surface 3 due to uneven thickness of the multicolor printing ink layer 5. When a printed film (indicated by 10 as a whole) having such irregularities is wound around a roller, as shown in FIG. 3, linear wrinkles 13 called “bones” (hereinafter simply referred to as “bones”). Often occurs). When the printing film 10 in which such bones 13 are generated is wound around the outer surface of the body portion of the metal can to exhibit its decorating properties, peeling of the multicolor printing layer 5 or dropping off of the adhesive occurs. Therefore, the commercial value of the metal can is significantly reduced due to poor appearance. In order to prevent such bone 13 from occurring, it is necessary to adjust the thickness of the multicolor printing layer 5 by applying correction ink in accordance with the present invention.

  That is, in FIG. 4 which shows an example of the cross-sectional structure in the printing unit surface 3, in this printing film 10, the multicolor printing layer 5 is formed by the ink layers 5a-5f of each color similarly to the printing film 10 of FIG. The multi-color printing layer 5 shows the same print design as the printing film 10 of FIG. 1, but in FIG. 4, a correction ink layer 15 is formed. 5 is adjusted, and the unevenness on the printing unit surface 3 is alleviated, thereby preventing the generation of bone 13. For example, as shown in FIG. 5, in the printing film 10 in which the correction ink layer 15 is formed according to the present invention and the thickness of the multicolor printing layer 5 is adjusted, the commercial value decreases when the printing film 10 is wound around a roller. The generation of the bone 13 leading to is effectively prevented.

  Since the correction ink layer 15 as described above does not form a print design, ink of a color that does not appear on the surface A side where the print design is observed and does not affect the print design (for example, white or milky white) ). For example, in the example of FIG. 4, the correction ink layer 15 is provided between the glitter ink layer 5e and the white ink layer 5f, and is hidden from view by the glitter ink layer 5e. Of course, the present invention is not limited to this example. For example, the correction ink layer 15 can be provided on the white ink layer 5f as long as the color tone of the white ink is not impaired.

  In the present invention, the correction ink layer 15 as described above has a printing design separately from the plate roller for each color for forming the ink layers 5a to 5f for each color (that is, the plate roller for forming the printing design). A stencil roller for forming is produced based on the stencil data, and the stencil roller is used to apply correction ink at a predetermined position and a predetermined timing.

The preparation of bone plate data is performed by the following process using a computer equipped with a monitor.
(A) Preparation of plate making data for each color ink (b) Calculation of total gradation value for each color ink in divided area and creation of temporary graph (c) Correction of temporary graph (d) Creation of bone plate data

Preparation of plate making data (a);
Since the bone plate data is for reducing unevenness in the distribution of the ink amount to such an extent that no bone is generated, naturally, the plate making data for each color ink forming the multicolor printing layer 5 is necessary to create this. Is required.

The plate-making data for each color ink is an image (print design) to be formed by printing, that is, an image to be formed by a printing unit surface, read by an appropriate image processing software, and this is designated as a raster image. The size (vertical and horizontal), the number of pixels (vertical and horizontal), the gradation value, etc. are stored as plate making data for each color ink.
Based on this plate-making data, a plate roller having cells having a predetermined size and depth is formed for each color ink.

  In preparation of the above plate making data, the stencil preliminary data is prepared at the same time, and this stencil preliminary data is created and used together with the plate making data for each color ink to create the stencil data. it can.

Temporary bone data is, for example, based on plate making data for each color ink, based on an image obtained by superimposing ink images of each color (for example, an image displayed on a monitor), based on the experience and intuition of the operator, Is created by setting the place where the ink is applied, the amount of ink, and the printing order, but it is usually created using image processing software.
That is, an image read by the image processing software and displayed on the monitor (an image obtained by superimposing the ink images of the respective colors) is binarized with a predetermined threshold for the thickness and displayed as an image. That is, by this binarization processing, for example, a portion thicker than a predetermined threshold is displayed in black and a thin portion is displayed in white, and the primary correction ink is applied to the white portion having a small thickness in a certain amount. As described above, provisional stencil data such as cell coordinates and depth of the stencil roller for applying the correction ink and printing (application) timing are created.

Calculation of total gradation value and creation of temporary graph (b);
Next, for each plate-making data of each color ink, a single-color total gradation value corresponding to the amount of ink existing in a certain area of the printing unit surface is calculated.
The amount of ink existing in a certain area of the printing unit surface is correlated with the sum of the pixel gradation values in the pixel area of the plate-making data corresponding to that area. Therefore, if the total gradation value for a single color is obtained, the amount of the single color ink can be determined.
That is, with reference to FIG. 6 showing the printing unit surface 3, the unit surface 3 is divided into regions (divided regions) 20 having a constant width w perpendicular to the printing direction, and from the plate-making data for each color ink. For each divided region 20, a single color total gradation value is calculated for each color ink. This monochromatic total gradation value is obtained as follows.
When the resolution of the plate-making data of each color ink is R (dot / mm = dpm), the width w (mm), and the number of pixels H present in the horizontal direction (printing direction),
Number of pixels existing in the divided area 20 = w * R * H
If the gradation value of the i-th pixel in the divided area 20 is G (i),
Monochromatic total gradation value = G (1) + G (2) +... + G (w * R * H)
It becomes. Here, when the plate-making data has 256 gradations, G (i) takes a value of 0 to 255. G (i) may be normalized to 100%.
That is, this single-color total gradation value corresponds to the printing amount of each ink existing in each divided area 20.

As described above, the single color total gradation values existing in the divided areas 20 calculated for each color ink are stacked for each divided area 20, and all the colors obtained by adding up the single color total gradation values of the inks of the respective colors are combined. A provisional graph indicating the total gradation value is created.
An example of this provisional graph is shown in FIG.

In the provisional graph of FIG. 7, the side perpendicular to the printing direction of the printing unit surface 3 is divided into about 4000, and the monochromatic total gradation of the ink of each color is divided into 4000 divided areas 20 each having a minute width w. The values are stacked in the order of printing, and the total gradation values of all colors in each divided region 20 are shown over the entire printing unit surface 3. That is, in the example of FIG. 7, ink a (for example, black color), ink b (for example, brown color), ink c (for example, indigo color), ink d (for example, grass color), ink e (for example, red color), ink f (for example, yellow color) In addition, the monochromatic total gradation values of the inks for the seven colors of the ink g (for example, white) are superimposed in the printing order.
Since the number of divisions is large and the width w is very fine, ruled lines that divide the divided regions 20 are omitted in FIG.

  According to the above provisional graph, regarding the divided region 20 having a width w obtained by equally dividing the printing unit surface 3 into a large number along the printing direction, the total gradation values of all the colors, that is, the total ink amount (for each color) The distribution state of the total amount of ink) can be easily grasped visually. That is, in the region where the total ink amount protrudes locally, when the long film on which such printing is performed is wound around the roller, the long printing film 10 is used as the roller in the portion where the protrusion is large. When winding up, the part overlaps dozens, so it is a region that protrudes locally and generates bone, and by displaying such a temporary graph on the monitor, the region where bone is generated It can be easily recognized, which is a great advantage of the present invention.

  Further, since it is possible to recognize whether or not bones are likely to be generated by the provisional graph, in order to more specifically visually identify the bone generation portion, for example, a monitor on which the provisional graph of FIG. It is also possible to display the print images indicated by the print unit surface 3 side by side with the same length.

Correction of temporary graph (c);
In the present invention, in the following process, the provisional graph is corrected, and a correction graph in which the application amount and the application position of the correction ink are set is created.
That is, in the provisional graph shown in FIG. 7, the region where the total tone value of all colors corresponding to the total ink amount is the maximum (the portion indicated by MAX in FIG. 7) is used as a reference, and the entire reference region is displayed. The total tone value of the correction ink in the divided region 20 where the total tone value of all colors is insufficient so that the total tone value (MAX) is 60 to 110%, particularly 70% or more and less than 100%. Is added to create a modified graph.

  An example of this modified graph is shown in FIG. That is, in FIG. 8, x is an area where the total gradation value of the correction ink x is added. For example, while observing the temporary graph of FIG. Accordingly, the total gradation value pixel number of the correction ink x is appropriately added so that, in any divided region 20, the total gradation value in the above-described range is shown with respect to the maximum total gradation value of all colors. The temporary graph is corrected.

  When creating the correction graph as described above, the total gradation value of the correction ink x is not always added to the region where the total gradation value of all colors is the smallest. For example, in a region where the total gradation value of all colors is the smallest, when there is little color overlap and the single-color total gradation value (ink amount of each color) of each color ink is small, the printing obtained by adding a large amount of correction ink x This is because the hue of the image may change.

  In addition, the total gradation value of the correction ink x to be added is the maximum total gradation value of all colors in any divided area 20 with respect to the maximum total gradation value of all colors in all areas. What is necessary is just to set so that it may become in the said range with respect to a tone value. That is, when the provisional graph of FIG. 6 and the correction graph of FIG. 7 are compared, the region showing the maximum total color total gradation value MAX is the same, but this region may be different. In short, in the correction graph of FIG. 8, all the total color gradation values in each divided region 20 are within a predetermined range with respect to the maximum value of the total gradation value of all the colors including the correction ink x. It only has to be.

  Furthermore, the larger the area where the correction ink is applied, the easier the formation of the cells with the correction ink roller. For this reason, in the example shown in FIG. 8, the correction ink is set to be applied over the entire width direction of the printing unit surface (perpendicular to the printing direction), and the total added in each region is set. Correction with the correction ink is performed by adjusting the gradation value (application amount of the correction ink).

  Note that, on the monitor screen showing the correction graph of FIG. 8, the print images indicated by the print unit planes 3 may be displayed in parallel by matching the lengths in the width direction as in the temporary graph of FIG. it can. As a result, it is possible to quickly recognize which part of the printed image is applied with the correction ink.

Creation of bone version data (d);
Based on the correction graph created as described above, bone version data is created. In other words, the correction ink application position (cell coordinates), application amount (ink amount), application sequence, etc. are set based on the correction graph, for example, stored as bone data together with the data of the temporary graph and correction graph described above. Is done.

  Further, in the above-described example, a provisional graph indicating the total ink amount in the divided area 20 is created based on the plate-making data of each color ink. However, the provisional graph is set roughly when creating the provisional graph. It is also possible to use temporary stencil data for correction ink.

That is, the stencil provisional data can be roughly set according to the experience of the operator who creates the data, and the thickness of the multicolor printing layer on the printing unit surface 3 by using the plate-making data of each color ink. A processed image obtained by binarizing the image is formed, and based on this processed image, the position for applying correction ink (which is a temporary setting because it is a temporary setting) can be roughly set.
In such a case, the total gradation value of the primary correction ink is added to the provisional graph of FIG. 7 described above according to the portion to be coated. In the graph of FIG. 8 in which the temporary graph is corrected, the area of the correction ink x is the sum of the primary correction ink and the correction ink (secondary correction ink) added for correction. The bone plate data as the correction ink is created by combining the secondary correction ink and the secondary correction ink.

  In creating the bone data as described above, it is preferable to create the provisional graph and the correction graph by dividing the printing unit surface 3 into a larger number and setting the divided region 20 having the width w. In other words, as long as the resolution of the raster image of each color ink formed based on the plate-making data of each color ink allows, the more precisely the divided area 20 is set, the more precisely the bone generation site based on the uneven thickness of the ink amount is specified. This is because, for example, the width w of the reference unit surface 3 (the direction perpendicular to the printing direction) is divided into 1000 or more, preferably 3000 or more, and most preferably 4000 or more, and the width w of the divided region 20 is set. It is good.

  In the present invention, a plate roller for each color ink is manufactured based on the pre-prepared data for each color ink, and a bone plate roller for applying correction ink from the above-described bone plate data is laser-produced. The correction ink layer 15 as shown in FIG. 4 described above is produced by, for example, processing, and performing multicolor printing by applying and drying ink using these rollers for each ink in a predetermined order. The long printing film 10 provided is obtained.

  Note that, as described above, the printing order is performed such that a predetermined printing design is shown and the correction ink layer 15 is not observed from the outside. In general, when the correction ink is applied to the multi-color printing layer 5 having the layer structure as shown in FIG. 1, the correction ink is formed lastly by applying the correction ink. It is common.

After the multicolor printing, an adhesive is applied on the multicolor printing layer 5 including the correction ink layer, and the printing unit surface 3 is formed in a plurality of rows as shown in FIG. Are separated into each row by a slitter and wound around a roller for each row.
In the printing film 10 wound around the roller in this way, generation of bones 13 is effectively prevented by adjusting the thickness of the multicolor printing layer 5 made by the above-described means.

The long printing film obtained as described above is cut for each printing unit surface, for example, the above-described printing unit surface 3 side (the side on which the multicolor printing layer 5 is formed and the adhesive is applied). ) Is adhered to the outer surface of the body of a metal can such as a seamless can or a welded can, and then the finish varnish is formed on the surface side of the film (the surface on which the multicolor printing layer 5 is not formed). Next, after finishing the finish varnish and curing the adhesive by oven heating or the like (or irradiation with ultraviolet rays, electron beam, etc.), neck-in processing, flange processing, etc. are performed, and a predetermined label can It will be transported to the seller.
Further, the printed film can be used for forming a bag-like container (pouch), for example, in addition to being applied to a metal can.

  In addition, in the above-described printing film, the long film on which printing is performed is not particularly limited as long as printing is possible, and is formed of a known transparent thermoplastic resin, For example, low density polyethylene, high density polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene or random of α-olefins such as ethylene, propylene, 1-butene, 4-methyl-1-pentene Olefin resins such as block copolymers and cyclic olefin copolymers; ethylene / vinyl copolymer resins such as ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, ethylene / vinyl chloride copolymer Polystyrene, acrylonitrile / styrene copolymer, ABS, α-methylstyrene / styrene copolymer Styrenic resins such as coalescence; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer, polymethyl acrylate, polymethyl methacrylate; nylon 6, nylon 6-6, nylon 6 10, amide resins such as nylon 11 and nylon 12; polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polycarbonates; polyphenylene oxide; biodegradable resins such as polylactic acid; Good. In general, it is excellent in transparency and at the same time has good heat resistance to heat treatment (drying of ink and finishing varnish, curing of adhesive, etc.) performed when producing this printed film. In this respect, polyester such as polyethylene terephthalate is preferable.

  Moreover, since the thickness of the long film 1 to which printing is performed is not particularly limited and is set to an appropriate thickness according to the application, it cannot be specified unconditionally, but when pasting on a general beverage can The thickness is about 8 to 30 μm. Such a film may be appropriately uniaxially or biaxially stretched.

  Furthermore, various inks used for multicolor printing are known per se, and pigments or dyes of a predetermined color are dissolved or dispersed in a solvent together with a binder according to the printing design and required functions. A known solvent-type paint is preferably used.

  Furthermore, the adhesive is used for sticking and fixing the printed film to, for example, the outer surface of a metal can. For example, a thermosetting, ultraviolet curable, or electron beam curable transparent polyester resin is used. Acrylic resin, epoxy resin, polyurethane resin, etc. are used. These are used by applying a coating liquid dispersed or dissolved in a predetermined solvent on the multicolored printing layer 5 of the printing film and drying it. After the film is attached to the outer surface of a metal can or the like, it functions as an adhesive by curing by heating, ultraviolet irradiation, electron beam irradiation, or the like.

  In the present invention, the present invention is not limited to the embodiment in which the ink layers 5a to 5f of the respective colors are formed in the order shown in FIG. 1 or FIG. 4, and for example, this position can be set in reverse. In this case, the print design is observed from the back surface B side without the film 1, and therefore the correction ink layer 15 is formed on the film 1, for example, so as to cover the other. An ink layer is formed, and the adhesive is formed on the reverse surface of the film 1 (surface B on the side where the multicolor printing layer 5 is not formed), and further, a finished varnish after being fixed to a metal can etc. Is applied onto the multicolor printing layer 5.

According to the present invention, it is possible to effectively prevent the occurrence of bone even when a thin film is used as a long film and a long film printed at a high speed is taken up. Can be reduced.
Further, since the bone plate data for the correction ink is created based on the visualized data, the bone plate data can be created reliably and in a short time.

1: long film 3: printing unit surface 5: multicolor printing layer 5a to 5f: ink layer of each color 10: printing film 13: bone 15: correction ink layer

Claims (4)

In a method for producing a printing film in which printing unit surfaces formed by a multicolor printing layer composed of an ink layer of each color are arranged on one surface of a long plastic film along the longitudinal direction of the film,
Prepare plate making data created for each color ink forming the multicolor printing layer,
Based on the plate making data, for each divided area of the printing unit surface having a constant width w perpendicular to the printing direction, a single color total gradation value corresponding to the ink amount is obtained by image processing for each of the inks of each color. Calculate
Based on the calculated value, for each of the divided areas, a provisional graph showing the total color total gradation value corresponding to the total ink amount of the inks of the respective colors is created over the entire printing unit surface,
The correction ink is applied to the divided area where at least the total color total gradation value is insufficient so that the total color total gradation value in each divided area is 60 to 100% of the maximum value of the total color total gradation value. Create a correction graph by adding the total gradation value of
Based on the correction graph, create bone plate data for the correction ink,
Using a plate roller for each color ink created based on the plate-making data and a bone plate roller made based on the bone plate data, an ink for each color ink is applied to one surface of the long plastic film. Winding on a roller while continuously performing printing with a correction ink and printing with a correction ink,
A method for producing a printed film.   The method for producing a printed film according to claim 1, wherein the width w of the divided region is set by equally dividing a width in a direction perpendicular to the printing direction of the printing unit surface into a large number of 1000 or more. Along with the plate making data of each color ink, prepare temporary stencil data created for the primary correction ink applied to the portion where the thickness of the multicolor printing layer is small,
For the printing unit surface, for each divided area having the constant width w, based on the plate-making data for each color ink, the single-color total gradation value is calculated for each color ink, and at the same time, based on the bone temporary data Calculating the total gradation value for the primary correction ink by image processing,
In the provisional graph, the total gradation value for the primary correction ink is stacked in each divided area,
The correction graph is created by adding a gradation value for the secondary correction ink to a divided region where at least the total ink amount is insufficient,
Based on the correction graph, the stencil temporary data is corrected, and stencil data for correction ink obtained by adding secondary correction ink to the primary correction ink is created.
The manufacturing method of the printing film of Claim 1 or 2.   Based on the plate making data prepared for each ink of each color, a processed image obtained by binarizing the thickness of the multicolor printing layer is formed on the printing unit surface, and multicolor printing is performed based on the processed image. The manufacturing method of the printing film of Claim 3 which produces the stencil temporary data about the primary correction | amendment ink for forming a correction | amendment ink layer in a part with small thickness of a layer.

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