JP5750747B1 - Fine line pattern forming method - Google Patents

Abstract

An object of the present invention is to form a line drawing having a fine line pattern of extremely fine uneven fine lines on the surface of a molded product, and to exhibit a changing effect in which reflected light of each part of the line drawing changes by changing the viewing angle and direction. A method for forming a fine line pattern is provided. A fine line pattern composed of a plurality of fine lines having a fine line pitch is formed on a surface of a printing film as a concavo-convex ink layer by printing, and is then placed in a cavity of a mold for forming an outer shape of a molded product. A printing film is placed with the ink layer forming an uneven fine line pattern, and after the mold is clamped, molten resin is injected into the mold to create a fine line pattern on the surface of the molded product in the mold. After the resin layer is solidified with the ink layer facing each other and the printing film is in close contact, the molded product is taken out after opening the mold, the printing film installed in the mold is repeatedly used for the next molding By doing so, a fine line pattern was formed on the surface of a plurality of molded articles with the same printing film. [Selection] Figure 1

Description

  The present invention relates to a method of forming a line drawing having a fine line pattern such as a pattern, a pattern, or a character with extremely fine uneven fine lines on the surface of a molded product, and the reflection of each part of the line drawing by changing the viewing angle or direction. The present invention relates to a method for forming a fine line pattern that can be applied to a changing image in which light changes.

  As a processing method for forming a concavo-convex pattern such as a pattern having unevenness, a pattern, a character, or the like on the surface of a molded product, there is a method using an engraving mold conventionally. However, when engraving a concavo-convex pattern on a mold, the line width (line thickness) is limited to about 0.3 mm, and it is difficult to engrave fine lines finer than that, and the cost of the mold There was a problem that became very expensive.

  By the way, as described in Patent Document 1, the applicant of the present invention uses a pattern composed of a large number of concave and convex lines as a pattern of an arbitrary shape, and each part of adjacent patterns changes the angle of the concave and convex lines relative to each other. As a result of changing the reflected light by changing the viewing angle of each part of the pattern made up of numerous irregular stripes, the display has a changing effect that changes the impression of the pattern. .

  However, in Patent Document 1, when the display body is formed by screen printing, for example, the thickness (line width) of the line is 30 μm to 1 mm and the pitch of the line is 60 μm to 2 mm. With the method of engraving the concavo-convex pattern, it is impossible to form the fine lines as described above.

  Then, "the film with an uneven | corrugated pattern and its manufacturing method" of patent document 2 is examined as a prior art which forms the above uneven | corrugated fine lines on the surface of a molded article. The content of this patent document 2 is that a concavo-convex pattern for transfer with a transparent ultraviolet curable resin and a printing ink layer for transfer applied to the concavo-convex pattern are formed on the surface of the film, and the concavo-convex pattern printing ink is applied. After placing the layer in the mold facing the cavity and performing in-mold molding, the printing ink layer made of an ultraviolet curable resin is transferred to the surface of the plastic molded product by peeling the film having the uneven pattern from the molded product. Is.

  However, in such a technique, the concavo-convex pattern for transfer by the transparent ultraviolet curable resin and the ink layer for transfer applied to the concavo-convex pattern are transferred to the plastic molded product and remain. That is, in this transfer method, the concavo-convex pattern formed on the ink layer is transferred to the surface of the molded product, and the concavo-convex pattern formed by the ink layer is formed on the surface of the molded product. There is a possibility that the layer may be damaged or peeled off due to wear or the like.

  Further, according to the method for transferring the ink layer as described above, since the transferred film adheres to the surface of the molded product, it is necessary to supply a new transfer film for each molding. Therefore, in the case of producing a plurality of molded products, it is necessary to supply a film on which a concavo-convex pattern is printed each time, resulting in waste in terms of production cost.

  In addition to the above-mentioned Patent Document 1, various methods for producing a changing image in which an image changes by changing the viewing angle and direction have been developed. However, in order to obtain a changing effect that changes the brightness of reflected light by changing the viewing angle of each part in the image, fine lines having a line width of 30 μm to 2 mm and a line pitch of about 50 μm to 2 mm are formed on the surface of the molded product. Since it has to be formed, it has been impossible to carry out with a conventional molding method using an engraving mold.

  Moreover, in consideration of the durability of the molded product, the uneven fine lines formed on the surface of the molded product do not transfer the printing ink layer to the surface of the molded product as described above, but on the surface of the molded product. It is desirable to form directly as an uneven shape.

Utility Model Registration No. 3122463 JP-A-6-72013

  The present invention has been made in view of the above circumstances, and forms a line drawing having a fine line pattern such as a pattern, a picture, a character, etc., by a very fine uneven fine line on the surface of a molded product, It is an object of the present invention to provide a method for forming a fine line pattern that exhibits a changing effect in which reflected light of each part of a line drawing changes by changing the direction.

In order to achieve the above object, the fine line pattern forming method according to claim 1 of the present invention is characterized in that a fine line pattern composed of a plurality of fine lines having a fine line pitch is printed on the surface of a printing film so as to have an uneven shape. After forming as an ink layer, when installing the printing film with the ink layer forming an uneven fine line pattern in the cavity of the mold that forms the outer shape of the molded product , the printing film should be in a flat state After being installed in the mold and clamped, molten resin is injected into the mold to form a molded product while thermally deforming the printing film into a three-dimensional shape according to the shape of the cavity in the mold. At the same time, after forming an uneven pattern according to the fine line pattern of the printing film on the surface of this molded product, solidifying the molded product, opening the mold and taking out the molded product, Next, leave the printing film By repeatedly used for molding, characterized in that so as to form a fine line pattern on a plurality of surfaces of molded products of the same printing film.

  The fine line pattern forming method of claim 2 according to the present invention is the method according to claim 1, wherein each fine line of the plurality of fine line patterns formed by printing on the surface of the printing film has a line width of 30 μm to 2 mm, The line pitch is 50 μm to 2 mm.

  The fine line pattern molding method according to claim 3 of the present invention is the method according to claim 1 or 2, wherein a resin having a heat resistant temperature of the printing film higher than the molding resin temperature of the molten resin to be injected into the mold is selected. The resin is used as a printing film.

  The fine line pattern forming method according to claim 4 of the present invention is the method according to claim 1, 2 or 3, wherein the pattern formed on the surface of the molded product is a pattern drawn with an ink layer on the surface of the printing film. Changing that is divided into a plurality of parts, and a lot of fine lines are drawn in parallel with each other at a predetermined pitch in the surface of each part, and such fine lines are drawn at different angles for each part area. It is a pattern.

  Furthermore, the fine line pattern forming method according to claim 5 of the present invention is the method according to claim 1, 2, or 3, wherein the pattern formed on the surface of the molded product is continuous with a short line spaced apart in a straight line direction. The broken lines arranged in the pattern are drawn as a line drawing patterned with different inclination angles, and a fine line pattern formed by combining the patterned line drawings is formed on the surface of the printing film with an ink layer. It is a changing pattern formed by a film.

  According to the method for forming a fine line pattern of the present invention, the ink layer forming the fine line pattern formed on the surface of the printing film can be used as a part of the molding surface of the mold. The concavo-convex fine line pattern corresponding to the concavo-convex ink layer on the surface of the printing film is formed. The fine line pattern formed on the molded product is an uneven fine line pattern formed by the fine uneven shape of the ink layer.

  Accordingly, the fine line pattern formed on the molded product according to the present invention is such that the surface of the molded product itself is formed in a concavo-convex shape. It does not occur and can be used as a molded article having excellent durability.

Moreover, the fine line pattern formed on the surface of the molded product according to the present invention is an uneven pattern formed by fine stripes formed by printing, and the line width is from 30 μm to 2 mm, and the line pitch is from 50 μm to 2 mm. By forming the fine line pattern formed, it is suitable for forming a changing pattern in which the reflected light of each part of the image changes by changing the viewing angle and direction.

  Furthermore, in the present invention, after forming once, a plurality of moldings can be performed by repeatedly using this printing film for the next molding in a state where an ink layer forming a fine line pattern is left on the surface of the printing film. Since a fine line pattern can be formed on the surface of the product, it is beneficial for reducing the molding cost.

  Further, as described above, in order to repeatedly use the printing film so that it can be used for the above molding, it is necessary to select a printing film having a heat resistant temperature higher than the molding resin temperature. By doing so, the printing film is not melted by the molding resin temperature, and can be supplied for reuse, and the same printing film can be used repeatedly for molding.

  The fine lines formed in the molded product according to the present invention are different depending on the fine line pattern by a straight line or a curve, or the brightness of the reflecting surface is partially changed by changing the viewing angle or the viewing angle is changed. It can be applied as a changing pattern in which an image can be seen or disappeared. In addition, as a molded product formed using the fine lines as described above, a bank card, a cash card, a pass ticket, a card for certifying the identity, a planar plastic card such as an IC tag, or a part or The present invention can also be applied to a molded product having a curved surface or a curved surface.

  Therefore, as the use of the molded product according to the present invention, in addition to the card-shaped molded product described above, a compact case, a panel for an automobile, a case for a mobile phone or a smartphone, and a case and a case of various electrical appliances, The present invention can be applied to the surface of a molded product that can be molded by applying the printing film according to the present invention. In addition, the present invention can be applied to resin-made flat or three-dimensional arts and crafts by utilizing the aesthetic characteristics of the fine line pattern according to the present invention.

  Furthermore, according to the present invention, it can be applied to an image for preventing forgery that is difficult to imitate by a combination of fine lines. For this reason, for example, a printed matter that needs to prevent counterfeiting or alteration of banknotes, stock certificates, passports, securities, cards, product tags, etc., such as a forgery preventing printed matter described in Japanese Patent No. 4395586. Even in the case of applying to resin molding, the fine line pattern molding method of the present invention is possible.

(A) is a top view which shows the state which formed the fine line pattern of Example 1 in this invention on the surface of a molded article, (b) is the figure which expanded a part of (a). It is the top view which formed the fine line pattern of Example 1 in this invention on the surface of the film for printing by screen printing. (A)-(f) is sectional drawing of the metal mold | die which shows the shaping | molding method of Example 1 by this invention. In an embodiment according to the present invention, it is a cross-sectional view showing a state in which a concave fine line pattern is formed on the surface of a molded article with a concavo-convex ink layer printed on a printing film, (a) is a situation at the time of molding Yes, (b) is the situation after molding, and (c) is a cross-sectional view showing the surface of the molded product. (A1)-(d1) is a top view which shows the line drawing and pattern line drawing regarding Example 2 of this invention, (a2)-(d2) is the top view which expanded the principal part of (a1)-(d1). It is. (A), (b) is a top view which shows the state which changes by changing the angle which the changing pattern formed by the pattern line drawing shown in FIG. 5 looks at.

  Embodiments of the present invention will be described below with reference to the drawings.

  In FIG. 1 (a), as a specific example of the molded article 1 according to the present embodiment, a case lid formed by forming a flower pattern as a fine line pattern 3 on a planar surface 2 whose periphery is curved toward the back side. It is shown. However, the molded product 1 in this figure is an example of the present invention, and if it is a molded product in which a molten resin can be molded by the mold 13 by injection molding, the surface 2 has a fine line pattern 3 according to the present invention. Can be formed.

  In this embodiment, a fine line pattern 3 as shown in FIG. 1 is drawn by image editing software of a computer, and this fine line pattern 3 is made on the surface 6a of a printing film 6 to be described later by a screen printing method. Printing is performed by placing ink or paste on the plate making.

In such screen printing, the printing film 6 constituting the printing surface includes polyethylene, polypropylene, polystyrene, polycarbonate, polyphenylene sulfide, polyimide, polyether ether ketone, polyamide, acrylonitrile butadiene styrene, acrylonitrile styrene, methacrylic. A resin film such as is used.
However, as will be described later, which resin is used as the printing film 6 should be selected in relation to the molding resin temperature described later.

  Further, in this example, in order to exert a changing effect in the fine line pattern 3 after molding, as shown in FIG. 1 (b) in which a part of the pattern 5 of the molded product 1 in FIG. 1 (a) is enlarged, The pattern 5 is divided into a plurality of portions 3a, the boundary 3b of each portion 3a is formed by a line drawing, and a large number of fine lines 4 are drawn in parallel with each other at a predetermined pitch on the surface of each portion 3a. A fine line pattern 3 is formed by drawing 4 at different angles for each region 3a. The fine line 4 that can be applied to the present invention can be applied not only to a straight line but also to a curved line, and can be applied not only to a solid line but also to a dotted line and a broken line.

  In addition, in order to ensure the heat resistance of the screen printing ink, screen printing is performed using an ultraviolet curable ink or an oxidation polymerization ink, and the fine line pattern 3 is formed from a surface of the printing film 6 having a height of about 10 μm, for example. It is formed as a convex ink layer 7 having a shape.

  In the present embodiment, the fine line pattern 3 may be drawn on the printing film 6 using screen printing, offset printing, or other printing methods. However, even if any printing method is used, each fine line 4 of the plurality of fine line patterns 3 printed on the surface of the printing film 6 has a line width of 30 μm to 2 mm in order to exert a changing effect after molding. The line pitch must be 50 μm to 2 mm.

  Further, as described above, the surface 2 of the molded product 1 (see FIG. 1A or FIG. 3D) is finely formed using the printing film 6 in which the convex fine line pattern 3 is formed by the ink layer 7. In order to form the line pattern 3, as shown in FIG. 3A, the ink layer 7 forming the convex fine line pattern 3 is printed in the cavity of the mold 13 that forms the outer shape of the molded product 1. Film 6 is installed. The mold 13 forms a cavity 11 for molding the molded product 1 between the fixed mold 13a and the movable mold 13b.

  Further, as a method for fixing the printing film 6, in addition to adhering to the peripheral surface of the mold 13 using a double-sided tape (not shown) or the like, considering the repeated use of the printing film 6, FIG. 2 (b), pin holes 9 formed in the periphery of the printing film 6 shown in FIG. 2 are inserted into the pins 8 provided in the periphery of the mold 13 and fixed by the following mold clamping ( (Refer FIG.3 (c)).

  Next, as shown in FIG. 3C, after the mold 13 is clamped, the molten resin 12 is injected into the cavity 11 in the mold 13 from the flow path 10 of the mold 13, and the molded product in the mold 13 is injected. The molten resin 12 is solidified in such a state that the ink layer 7 forming the fine line pattern 3 faces the surface 2 of 1 and the printing film 6 is in close contact therewith.

  As an example of the material of the molded product used in this embodiment, that is, a molten resin, polypropylene, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene, polycarbonate, or the like is used.

  In addition, although the printing film 6 is flat before the above molding, the film 6 is thermally deformed into a three-dimensional shape such as a curved shape according to the shape of the cavity 11 by facing the molten resin 12.

  Thereafter, as shown in FIG. 3D, after the mold 13 is opened, the printing film 6 deformed in a curved shape according to the molding surface of the mold 13 adheres to the molding surface 13 c of the mold 13. On the other hand, the molded product 1 peeled from the printing film 6 can be taken out.

  In such molding, if a release agent is applied to the surface 6 a of the printing film 6, the mold 1 is easily detached from the surface 6 a of the printing film 6 after the mold 13 is opened. It becomes possible to repeatedly use the printing film 6 adhered to the surface 13c for subsequent molding.

  In the present embodiment, as described above, the same printing film 6 is used, and surface processing can be repeatedly performed on a plurality of molded articles 1. For that purpose, the one in which the heat resistance temperature of the printing film 6 is higher than the molding resin temperature of the molten resin 12 injected into the mold 13 is selected so that the printing film 6 is not melted by the molding resin temperature. Must be used as the printing film 6.

  Specifically, the heat resistance temperature of the resin used for the following printing film 6 is compared with the molding temperature of the molten resin 12, and the heat resistance temperature of the printing film 6 is higher than the molding resin temperature of the molten resin 12. It is good to choose.

  Examples of the heat-resistant temperature of the resin used for the printing film 6 are: methacryl 90 ° C., polystyrene 100 ° C., polyethylene 110 ° C., acrylonitrile butadiene styrene 110 ° C., acrylonitrile styrene 110 ° C., polypropylene 140 ° C., polycarbonate 140 ° C., polyimide 230 ° C., polyphenylene sulfide 240 ° C., polyamide 250 ° C., polyether ether ketone 300 ° C.

  Further, examples of the molding temperature of the molten resin 12 include polypropylene 180 to 230 ° C., acrylonitrile butadiene styrene 220 to 260 ° C., acrylonitrile styrene 220 to 260 ° C., polyethylene terephthalate 230 to 280 ° C., and polycarbonate 240 to 300 ° C. .

  As shown in FIGS. 4A to 4C, the ink layer 7 forming the fine line pattern 3 formed on the surface 6a of the printing film 6 is used as a mold for molding the mold 13, as shown in FIGS. In the molded product 1 after molding, the concave / convex fine line pattern 3 corresponding to the concave / convex ink layer 7 on the surface 2 of the printing film 6 is formed.

  The fine line pattern 3 formed on the surface 2 of the molded product 1 as described above is an uneven pattern formed by fine stripes formed by screen printing, and has a line width of 30 μm to 2 mm and a line pitch of 50 μm to By making the fine line pattern 3 formed from 2 mm, the reflected light of each part of the image is changed by changing the viewing angle and direction as shown by A and B in FIG. 1 (b) and C in FIG. 4 (c). It is also suitable for forming a changing pattern that changes.

  In particular, in the present embodiment, a large number of fine lines 4 are drawn in parallel to each other at a predetermined pitch within the surface of each part 3a obtained by dividing the pattern 5 into a plurality of parts, and such fine lines 4 differ for each region of each part 3a. Since the fine line pattern 3 drawn at an angle is formed, the reflected light from each part 3a changes by changing the angle and direction of viewing the pattern 5, and the brightness increases or decreases for each part 3a. It is possible to express changing patterns.

  In this embodiment, the printing film 6 can be repeatedly used after molding once, with the ink layer 7 forming the fine line pattern 3 left on the surface 2 of the printing film 6. This is possible and is beneficial for reducing the molding cost.

  In Example 1 described above, an example of application to a changing pattern in which brightness is increased or decreased by changing reflected light from each part of the pattern divided by changing the angle or direction of viewing the pattern is shown. However, in Example 2, as described in Japanese Patent Application No. 2014-012049 which is the prior art of the present patent applicant, the molded product is viewed by forming a fine line pattern using a pattern line drawing on the molded product. It can also be applied to a changing pattern in which the pattern changes by changing the angle and direction.

  That is, according to the present embodiment, by changing the angle and direction of viewing the molded product, it is possible to form a changing pattern in which a visible image and an invisible image change among a plurality of images drawn inside the pattern. It becomes possible. As an example, in this embodiment, a fine line pattern using the pattern line drawing 19 shown in FIGS. 5 (d1) and (d2) is formed on the surface of the printing film 6 similar to that described in the first embodiment. Thus, as shown in FIGS. 6A and 6B, a changing pattern is formed in which the pattern changes by changing the angle and direction of viewing the molded product.

  As a specific example of such a changing pattern, in this embodiment, the line drawing 15a shown in FIGS. 5 (a1) and (a2) is the base pattern 18a, and the line drawing 15b shown in FIGS. 5 (b1) and (b2) is the first pattern 18b. The line drawing 15c shown in FIGS. 5 (c1) and 5 (c2) is defined as the second pattern 18c. In any of these line drawings 15a, 15b, 15c, as shown in FIGS. 5 (a2) to (c2), the short lines 16a, 16b, 16c are continuously arranged with a constant interval 17 in the linear direction. The broken line shapes 14a, 14b, and 14c are formed as line drawings 15a, 15b, and 15c that are continuously arranged with a certain length interval (line pitch) in the width direction of the short lines 16a, 16b, and 16c.

  In the above line drawings 15a, 15b, 15c, the numerical values such as the length of the short lines 16a, 16b, 16c and the interval 3 are exemplified. At the stage of drawing using a computer, the line width of each single short line 2 is 30 μm. ˜2 mm, length is 0.4 mm to 0.5 mm, the distance between the short lines in the linear direction is 0.2 mm, and the line pitch between the short lines and the short lines in the width direction of the short lines is 0.1 mm.

  However, in this embodiment, each short line 16a constituting the line drawing 15a (base pattern 18a) shown in FIGS. 5A1 and 5A2 is inclined 30 ° counterclockwise with respect to the horizontal line (that is, inclined rightward). Each short line 16b constituting the line drawing 15b (first pattern 18b) in FIGS. 5 (b1) and (b2) is formed in the vertical direction, and the line drawing 15c ((c1) (c2) shown in FIGS. Each short line 16c constituting the second handle 18c) is formed in a state of being inclined by α = 30 ° clockwise (ie, inclined to the left) with respect to the horizontal line.

  Next, in this embodiment, a line drawing 15a for forming the base pattern 18a shown in FIGS. 5 (a1) and (a2), a line drawing 15b for forming the first pattern 18b shown in FIGS. 5 (b1) and (b2), and FIG. A pattern line drawing 19 shown in FIGS. 5 (d1) and (d2) is formed by combining with the line drawing 15c forming the second pattern 18c shown in 5 (c1) (c2). The pattern line drawing 19 is formed by continuously arranging patterns composed of a plurality of short lines 16a, 16b, and 16c as described above.

  Next, an embodiment in which a specific pattern is drawn using the above-described three line drawings 15a, 15b, and 15c will be described. FIG. 5 (a1) shows a base pattern 18a as a background, and the line drawing 15a is formed over the entire region as a background. FIG. 5B1 shows the first pattern 8b, and a line drawing 15b in which each short line 16b is formed in the vertical direction is formed as a letter “A” as an example.

  Further, FIG. 5C1 shows the second pattern 18c, which is formed in a “heart shape” by taking this line drawing 15c as an example. Then, by combining these line drawings 15a, 15b, and 15c, a synthesized combined line drawing 18d shown in FIG. 5 (d1) is formed.

  In this embodiment, normal screen printing plate making is performed using a combined line drawing 18d as shown in FIG. 5 (d1) by image editing software of a computer, and ink or paste is placed on this plate making. Then, screen printing is performed on the printing film 6 as in Example 1.

  By such printing, a synthetic line drawing 18d is formed as an ink layer as a fine line pattern on the surface of the printing film 6, and the fine surface as shown in FIG. When a line pattern (synthetic line drawing 18d) is formed as a changing pattern, it is possible to obtain a changing effect in which the visible pattern changes as shown in FIGS. 6A and 6B by changing the viewing angle and direction. It becomes.

  That is, as shown in FIG. 6A, the first pattern 18b representing the letter “A” is clearly seen with the base pattern 18a in the background. As shown in FIG. By changing the viewing angle so that the second pattern 18c representing can be clearly seen, it can be applied as a changing pattern in which different images are visible or disappear on the surface of the molded article 1.

  The above changing pattern is an example, and is applied as a changing pattern expressing various patterns by making a fine line a solid line, a broken line, or by combining the solid line or broken line in a complicated manner. It is also possible.

  The fine line pattern forming method of the present invention forms a line drawing having very fine uneven fine line patterns, patterns, characters, etc. (fine line patterns) on the surface of the molded product, and changes the viewing angle and direction. Therefore, it can be used as a method for forming a fine line pattern that exhibits a changing effect in which reflected light of each part of a line drawing changes.

DESCRIPTION OF SYMBOLS 1 Molded product 2 Surface of molded product 3 Fine line pattern 3a Fine line pattern part 3b Fine line pattern boundary 4 Fine line 5 Pattern 6 Printing film 6a Printing film surface 7 Ink layer 8 Pin 9 Pin hole 10 Channel 11 Cavity 12 Molten resin 13 Mold 13a Fixed mold 13b Moving molds 14a, 14b, 14c Broken line shapes 15a, 15b, 15c Line drawing 16a, 16b, 16c Short line 17 Linear spacing 18a Base pattern 18d First pattern 18c Second pattern 18d Composite line drawing 19 Pattern line drawing A, B, C Changes in viewing angle and direction

Claims (5)

After forming a fine line pattern consisting of multiple fine lines with a fine line pitch on the surface of the printing film as a concavo-convex ink layer by printing, the concavo-convex fine pattern is formed in the mold cavity that forms the outer shape of the molded product. When installing the printing film with the ink layer forming a line pattern facing, after installing the printing film in the mold in a flat state and clamping it, by injecting molten resin into the mold, Forming a molded product while thermally deforming the printing film into a three-dimensional shape according to the shape of the cavity in the mold, and forming an uneven pattern according to the fine line pattern of the printing film on the surface of this molded product After solidifying the molded product, opening the mold and taking out the molded product, the printing film left in the mold is repeatedly used for the next molding, so that the same printing film can be used. Multiple molded parts table Method of forming a fine line pattern is characterized in that so as to form a fine line pattern on. 2. The fine line according to claim 1, wherein each fine line of the plurality of fine line patterns formed by printing on the surface of the printing film has a line width of 30 [mu] m to 2 mm and a line pitch of 50 [mu] m to 2 mm. Line pattern forming method. 3. The fine line according to claim 1, wherein a resin having a heat resistance temperature of the printing film higher than a molding resin temperature of a molten resin to be injected into the mold is selected, and the resin is used as the printing film. Pattern forming method. The pattern formed on the surface of the molded product is divided into a plurality of parts on the surface of the printing film, and a number of fine lines are drawn parallel to each other at a predetermined pitch on the surface of each part. 4. The method of forming a fine line pattern according to claim 1, wherein the fine line pattern is a changing pattern formed by a fine line pattern in which each region of each part is drawn at a different angle. The pattern formed on the surface of the molded product is drawn as a line drawing in which short lines are continuously arranged in the linear direction with a certain interval, and a broken line is patterned with different inclination angles. 4. The fine line pattern according to claim 1, 2, or 3, wherein a fine line pattern formed by combining line drawings is formed on the surface of the printing film with an ink layer, and is a changing pattern formed by the printing film. Molding method.