JPH0798393B2 - Method and apparatus for printing film for wrapping - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for printing a wrapping film by gravure printing and a printing apparatus used for the printing.

<Prior art and problems to be solved> When printing a synthetic resin film having a thickness of about 20 μ or more, which is conventionally used for a bag for packaging, etc., it is printed by a gravure printing machine. Wrapping film made of very thin polyethylene or polyvinyl chloride resin with a thickness of 20μ or less causes large wrinkles (wrinkles) around the ink-printed area as the ink-attached area shrinks significantly during printing. It has not been put to practical use because it will damage the appearance of the product packaging.

If an ink that does not react with the film is used because printing does not cause wrinkles, the adhesion of the ink to the film is poor and the ink peels off, which cannot be used because it is colored and harmful to foods. Further, since the wrapping film as described above has a thin material and undergoes a large amount of expansion and contraction due to heat, a method of heating and drying the ink by utilizing a short time during printing cannot be adopted.

On the other hand, as long as the wrap film is also used for packaging the product, generally print a pattern or pattern on the wrap within the range that does not impair the transparency of the product to make the original package,
Alternatively, it is strongly desired to print a barcode for displaying a price. Furthermore, wrap films are mostly used for fresh foods and processed foods that are easily altered, but since these foods are often exposed to ultraviolet rays such as fluorescent lights during the distribution process and display, they are oxidized, decolorized, discolored, and fresh. This is a cause of deterioration of quality such as deterioration.

On the other hand, as already mentioned, it is virtually impossible to print on the wrapping film, so it is not possible to deal with it by printing, and there is no printing ink itself that blocks ultraviolet rays. However, an opaque wrap film must be used as a measure against ultraviolet rays, but there is a problem that it is unsuitable as a packaging material because the contents cannot be seen.

<Means for Solving the Problems> With respect to the above-mentioned problems, the printing method of the present invention has one or more plate cylinders on the synthetic resin film 19 wound from the supply roller 13 and wound by the winding roller 16. In the method of performing gravure printing by contacting 23, with respect to the supply speed of the film 19, the peripheral speed of the plate cylinder 23 or each plate cylinder and the winding speed of the winding side are sequentially increased as the winding speed approaches the winding side. A speed difference is set so that the film 19 becomes higher, the wrinkles generated by printing are stretched and removed by the expander roller 33 before the film 19 is wound on the winding roller 16, and when the film 19 is wound on the winding roller 16, the pressing roller 36 is used. The film is wound so that the film is pressed against the winding roller 16 side to be pressure-bonded and laminated.

Further, in the above-mentioned printing method, the ink used for the plate cylinder 23 is an ink having an ultraviolet ray shielding function, and the ultraviolet ray shielding portion having a transparency through which an object to be packaged can be seen through is printed by the ink.

Alternatively, in the printing method, the bar code 40 for displaying the commodity price is printed near the end of the film 19 having a small amount of expansion and contraction during packaging.

The apparatus used in the above printing method is an apparatus in which one or more printer sections C ₁ are provided between the supply section A ₁ and the winding section B ₁ of the film 19, and the supply roller 13 in the supply section A ₁ is The peripheral speed of the plate cylinder 23 of the printer unit C ₁ and the winding speed of the winding roller 16 of the winding unit B ₁ are sequentially increased with respect to the film supply speed, and after printing is completed on the winding unit B _1. Expander roller that removes wrinkles from film 19 before winding
33 and a pressing roller 36 that elastically presses the film 19 against the winding roller 16 to press it when the film 19 is wound up, and a heating roller for heating the film 19 by the expander roller 33. It is characterized by being.

<Operation> In the present invention, from the supply side of the film 19 to the printer unit C ₁
Or, by increasing the winding speed toward the winding side, printing and winding were accurately performed while preventing wrinkles in the longitudinal direction of the thin wrapping film and slack in the middle of feeding, and further occurred by printing. Wrinkles are stretched and removed by the expander roller 33. Also take-up roller 13
In the above, since the film 19 is pressed against the press roller side against the peripheral surface of the take-up roller 13 and wound while being pressure-bonded, the film 19 is adjusted to a predetermined size and wound in close contact with each other. To be

Further, by forming a transparent ultraviolet shielding portion on the film 19 using an ink having an ultraviolet shielding function at the time of printing, ultraviolet shielding of the contents is performed while the inside of the package can be seen through.

Further, by printing the barcode 40 on the wrapping film 19, it is not necessary to attach a barcode printing sticker or the like as in the conventional case, and the manufacturer and unit price of the product at the sales stage can be easily confirmed by the reader.

<Example> FIG. 1 shows an apparatus (printing machine) for carrying out the method of the present invention.
An example is shown, and in this example, a structure in which 1 to 5 color printing is possible is shown.

The frame 1 of the printing machine has columns 4, 6 and 7, 8 standing upright at the left and right ends between the upper and lower beams 2 and 3 with a predetermined interval, and inside these, a printer frame 11, which also serves as a column. Twelve, for example, are provided at three locations on the left side and two locations on the right side, standing up at regular intervals.

A supply frame 14 which rotatably supports a supply roller 13 on its outer circumference is rotatably supported on the struts 6 and 7, and a winding frame 17 which rotatably supports a winding roller 16 on the outer circumference is rotated on the stanchions 4 and 8. Freely supported. Each of the rollers 13 and 16 comprises a winding shaft 18 made of a paper pipe as shown in FIG.
The mechanism is such that 18 is pressed and held from both sides by a conical support shaft (not shown) to be driven to rotate. When the supply of the film 19 wound around the supply roller 13 is completed and when the take-up roller 16 finishes the winding of the film 19, the supply frame 14 or the take-up frame 17 is rotated by a predetermined angle and set in advance. The rollers are exchanged by moving and setting the other rollers 13 and 16 in place at predetermined positions. With this mechanism, in this embodiment, the supply portions A ₁ and A ₂ of the film 19 and the winding portions B ₁ and B ₂ are formed on the support columns 6 and 7 and the support columns 8 and 4, respectively.

The printer units C _{1 to} C ₅ (however, the printer units C _{2 to} C ₄ are not shown) are respectively attached to the three printer frames 11 and the two printer frames 12 described above, and each printer unit C Heater boxes 21, 22 on the left and right for _{1 to} C ₅
Each is equipped with a plate cylinder and the lower surface is coated with ink.
The 23 and the impression cylinder 24 are supported as a set, and the film 19 is introduced through the heater box 21 and passes between the plate cylinder 23 and the impression cylinder 24, and then passes through the heater box 22 and the next. Sent to the printer section of.

A pinch roller 26, which is driven so as to extend the wrinkles of the film 19 and to give a tension, is axially supported above the supply portions A ₁ and A ₂ , and up to the impression cylinder 24 in front of and behind the pinch roller 26. Between the printer units and between the printer units, and further between the last printer unit and the winding units B ₁ and B ₂ of the printing line, a large number of relay rollers 27 that guide the film 19 are axially controlled at appropriate positions. There is.

Of the relay rollers 27, the film is placed in front of the plate cylinder 23.
A high-quality water-absorbent sheet (not shown) is wound around the outer circumference of the relay rollers 27a to 27d which are in contact with the printing surface side of the film 19 and have a relatively large film folding angle. That is, most of the currently used wrap films are added with a surface-active agent for preventing the fogging on the inner surface of the packaging and for softening the wrap film itself and enhancing the mutual adhesiveness. If it leaches to the surface by bending, stretching or the like, the adhesion and penetrability of ink on the plate cylinder 23 deteriorates and peeling occurs, so in order to prevent this, the relay rollers 27a to 27d are used.
In the absorbent sheet of No. 3, the surfactant leached on the printing surface is absorbed and removed in advance. 28 is a folding roller for feeding the film 19 to the next printer section.

The heater boxes 21 and 22 have an atmosphere for warming the film 19 to about 40 ° C. by irradiating far infrared rays inside the heater boxes 21 and 22. This is in front of the plate cylinder 23 depending on the feeding direction of the film 19. In this case, no heating action is performed to avoid heating of the film 19, but when it is located rearward, the above-mentioned heating atmosphere is formed to enhance the adhesiveness (permeability) of the adhered ink and accelerate the drying.

A cooling roller 29 is provided at the end of each printing line to cool the film 19 heated in the printer section at the end of the line and to stabilize the material and dimension. The water is circulated so as to keep the temperature around 15 ° C, for example.

2 and 3 show the arrangement of the rollers in the winding sections B ₁ and B ₂ , 31 is a winding pinch roller composed of a vertically movable rubber roll, and the outer periphery of which is a metallic winding roller. The pinch rollers 32 are axially supported, and below them (on the rear side of the line) are expander rollers 33 which are heating rollers or non-heating type rolls having a smooth peripheral surface, and folding rollers 34 which are located slightly apart from the expander rollers 33. It is pivotally supported. The expander roller 33 is for extending and removing wrinkles generated on the ink-adhered portion by printing, and when wrinkling is severe due to the amount of ink determined by the material and the size of the printing area, the peripheral surface temperature For example, use a heating roller with a built-in heater so that it can be heated to about 100 to 120 ° C, and if wrinkles are less likely to occur, simply stick firmly to the peripheral surface and wind it to extend the wrinkles. A heating roller is used.

A pressing roller 36 that elastically presses the film 19 to be wound onto the outer circumference of the winding roller 16 with a strong pressing force is rotatably supported on the outer circumference of the winding roller 16 that stops at the normal position and operates.
The pressing roller 36 allows the film 19 to be successively wound around the peripheral surface of the winding roller 36 while being pressed against each other, and the pressing force at this time keeps the film width at a predetermined width. Is controlled. When the deformation due to printing (crease of wrinkles) is corrected by the expander roller 33 and the film is wound up without the pressing roller 36, the dimension of the film 19 and the printed pattern (especially in the case of bar code printing) is stable and normal. It is difficult to secure winding in the crimped state. Reference numeral 37 is a spring that adjustably and elastically presses the pressing roller 36, and 39 is a thermostat box that adjusts and sets the temperature of the expander roller (heating roller) 33.

Next, a method for printing a wrapping film using the above printing machine will be described.As the wrapping film, a commonly used polyvinyl chloride-based film having a thickness of 10 to 20 μ or a polyethylene-based film having a thickness of around 10 μm is used. used. First, in order to give the original film a hardness, it is attached to the supply section A ₁ as the supply roller 13 in a state of being cooled to, for example, about 10 ° C., and a printing line like a film 19 shown by a solid line in FIG. 1 is formed.

Subsequently, the supply roller 13, the pinch roller 26, the plate cylinder 23, the pinch roller 32, and the take-up roller 16 are driven in a predetermined direction to start printing, but at the time of printing, the temperature setting of each portion already described is performed in advance. . At this time, the ink used for the plate cylinder 23 is
For printing ordinary patterns and barcodes 40 (see Fig. 4), diluted ink generally used for polyvinyl chloride or polyethylene film is sufficient, but the dilution rate depends on the density of the desired color. Adjusted.

In the line (of the film 19) shown by the solid line, three printer units C _{2 to} C ₄ (not shown) are interposed between the printer units C ₁ and C ₅ , and printing of five colors is performed as a whole, and the winding is performed. The take-up roller 16 of the take-up section B ₁ successively takes up.

When the film 19 supplied from the supply unit A ₁ is printed in three colors, the film 19 is folded back by the folding roller 27e via _three printer units C ₁ and printer units C ₂ and C _{3 (} not shown). A line as shown by the chain line in FIG. 1 is formed and is wound up by the winding roller 16 of the left winding unit B ₂ .

On the other hand, when the film 19 is supplied from the supply roller 13 of the supply unit A ₂ on the right side and is printed in two colors and wound around the winding unit B ₁ , the folding roller 27f between the printer units C ₃ and C ₄ (not shown)
Up to the film 19 forms a line indicated by a chain line, two-color printing is performed by the printer units C ₄ and C ₅ , and the film is wound around the winding roller 16 of the winding unit B ₁ .

As described above, in the embodiment shown in the drawings, film printing of 1 to 5 colors is possible depending on the number of printer units and the arrangement of the folding rollers 27e, 27f and the like, and the arrangements of 1 to 4 colors are different colors at the same time. A number of different prints can be done in parallel.

In the above printing, it is practically impossible to perform a normal gravure printing of a film having a thin film thickness and high elasticity, as described above, due to deformation or damage due to heating or tension during printing, misalignment of feeding, etc. However, in order to cope with this, in addition to cooling by the cooling roller 26 or the like during the movement of the film 19, a predetermined amount is set for each of the printer units C _{1 to} C ₅ and further before the winding units B ₁ and B ₂ . The peripheral speed difference (acceleration) is set to feed the film.

That is, for example, in the case of the line of the film 19 shown by the solid line, if the peripheral speed of the supply roller 13 is 100 m / min, the plate parts are fed at speeds of about 1 m / min in each of the printer sections C _{1 to} C _5. The rotation peripheral speed of the cylinder 23 is increased to a feed speed of about 105 m / min in the final printer section C ₅ , and it is increased to about 108 m / min in the pinch roller 32 in front of the winding section B ₁ , and the winding section is further increased. The winding speed of the winding roller 16 of B ₁ is increased to about 110 m / min. In this way, by gradually increasing the film moving speed toward the winding side, problems such as slack and deformation of the film during printing, damage or misalignment are solved and the action of the expander roller 33, the pressing roller 36, etc. As a result, the wrinkles of the film are removed, and the film can be wound and stocked on the winding roller 16 with the same size as when the original supply was started.

The speedup for each printer section and the speedup in the winding sections B ₁ and B ₂ at the time of film printing as described above are similarly performed in the case of the line indicated by the broken line or the chain double-dashed line in FIG. 1, and It is desirable that these acceleration amounts are adjusted depending on the material of the film 19. The acceleration amount is increased when the original material of the film has a large elasticity, and the acceleration amount is decreased when the elasticity of the original film is small. Further, the peripheral speed of each roller that is rotationally driven is changed by attaching and detaching rollers having different diameters.

When printing the bar code 40 in the above printing, as shown in FIG. 4, the bars are printed so as to be aligned in the width direction along the longitudinal direction of the film 19, and the printing portion is relatively expanded and contracted during the automatic lap. Select a position where the quantity is small, for example, the position behind the tray to be packed. The orientation and the printing position of the bar code 40 are for preventing the bar code interval from changing due to the film 19 being pulled in the longitudinal direction during the automatic lap or a large extension on the tray surface side. Further, it is desirable that the length, thickness and interval of the bar code be enlarged in advance and printed according to the amount of expansion and contraction of the film during the automatic lap. Both are for preventing an error when reading a barcode.

Next, the UV shielding printing on the film 19 will be described. Although the printing process in this case is the same as the method shown in FIGS. 1 and 2 described above, the UV shielding after printing is performed as the ink used for the plate cylinder 23. A material that has a closing effect and can be transparent is used. That is, the polyethylene-based film and the polyvinyl chloride-based film have an ultraviolet shielding effect of about 10 to 15% by themselves, but as described above, in the embodiment of the present invention, a high ultraviolet shielding effect is obtained by printing. The printed portion is transparent or at least has a transparency that allows the contents to be seen through.

FIG. 4 shows the UV-shielding printed film. In the illustrated example, in addition to the bar code 40 described above, a UV-shielding portion 41 having a transparency that allows the inside of the package to be seen through is provided in the approximate center of the film 19. It is printed in strips. The ultraviolet shielding part
When the tray (not shown) is wrapped with the film 19 for example, the width of the 41 needs to be the width required for the ultraviolet shielding portion 41 to cover substantially the entire front surface side of the tray. It can be adjusted by changing the plate cylinder according to the size of other packages.

The ink used for the above printing was made for transparent printing on the wrap film, and the following ink and solvent (diluting liquid) were used according to the material of the film 19.

I. In the case of PVC film Ink: Toyo Ink Mfg. Co., Ltd. V140-VCSP-V Solvent: Toyo Ink Mfg. Co., Ltd. S642 b. In the case of polyethylene film Ink: PEK-V manufactured by Toyo Ink Manufacturing Co., Ltd. Solvent: GN-102 manufactured by Toyo Ink Manufacturing c. Other matters Ink dilution ratio… In any case, the weight ratio of the dilution liquid 50 to 60 with respect to the ink stock solution 100 Standard of printing viscosity… A-15 to 20 sec (25 ° C) Plate depth standard… 35 μ (conventional 175 l) Ink Safety: Compliant with voluntary regulation (NL regulation) for printing ink for food packaging materials Hue: White (however, yellow, vermilion, red, grass, indigo, and brown are possible) Other handling: Same as normal gravure ink As a result of printing under the above conditions, at least 96 to 98% of the irradiated ultraviolet rays were blocked by the ultraviolet blocking section 41 of the printed film. An ultraviolet intensity meter (UVR-365 type) manufactured by Tokyo Optical Machinery Co., Ltd. is used for measuring the ultraviolet blocking rate, and the magnification filter (1/80) is 200 to 400 nm. Although the transparency was not measured quantitatively, the printed part was extremely pale and cloudy (it is understood that it was due to the additive component to the ink), but it was sufficient to confirm the color and freshness of the contents as well as the shape of the contents. there were. It has been confirmed that if any of these colors other than white is used, there is almost no turbidity, and printing can be performed almost in a colored and transparent manner.

<Effects of the Invention> According to the method and apparatus of the present invention configured as described above,
Since it is possible to print patterns on wrap films, which were thought to be almost impossible in the past, it is possible to make original wrapping film-free wrap films that have been treated with zezain according to the properties of the packaged food, sales strategy, etc. In addition to the safe wrapping that does not cause ink peeling,
It is possible to provide a transparent portion on these wraps or to obtain a highly transparent printing film that allows the contents to be seen through. Further, these have a great advantage in terms of economy such that a conventional design container or the like can be replaced with a wrap film packaging.

Further, not only the pattern but also the cost and the bar code displayed by the manufacturer can be printed, so that the product wrapped in the wrap film can be directly read by the reader for identification, which greatly contributes to labor saving of calculation and identification.

In addition, it is possible to print highly transparent UV shielding parts at major positions on the film with UV shielding ink, and as a result, fresh foods and processed foods are transported by the fluorescent lamp and germicidal lamp during the storage, display and display process. There is an advantage that there is no risk of deterioration due to ultraviolet rays, and the storage period of these foods can be extended.

[Brief description of drawings]

FIG. 1 is an overall front view of the gravure printing machine used in the method of the present invention, with some parts omitted, and FIGS. 2 and 3 are partial front view and side view showing the structure of the print film winding section, and FIG. [Fig. 3] is an external view of a wrap film that has been subjected to ultraviolet shielding printing. 13: Supply roller, 16: Take-up roller 19: Film, 23: Plate cylinder 33: Expander roller 36: Pressing roller, A ₁ , A ₂ : Supply section B ₁ , B ₂ : Winding section, C ₁ , C ₅ : Printer section

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G06K 1/12

Claims (5)

[Claims] 1. A synthetic resin film (19) wound around a supply roller (13) and wound around a winding roller (16).
In the method of performing gravure printing by contacting at least two plate cylinders (23), with respect to the supply speed of the film (19),
A speed difference is provided so that the peripheral speed of each plate cylinder (23) or each plate cylinder and the winding speed on the winding side gradually increase as the winding speed approaches the winding side, and the film (19) is wound onto the winding roller (16). ) Before the film is wound on the take-up roller (16), the expander roller (33) stretches and removes wrinkles generated by printing, and when the film is taken up on the take-up roller (16), the film is pressed by the pressing roller (36) to the take-up roller (16) side. A method for printing a film for wrapping, which is rolled so that it is pressed against and pressure-bonded. 2. The ink used for the plate cylinder (23) is an ink having an ultraviolet ray shielding function, and the ultraviolet ray shielding portion having a transparency through which the article to be packaged can be seen through is printed by the ink. The method for printing a wrapping film according to item 1. 3. The method for printing a wrapping film according to claim 1, wherein a bar code (40) for displaying a commodity price is printed near the end of the film (19) having a small amount of expansion and contraction during packaging. . 4. An apparatus in which one or more printer sections (C ₁ ) are provided between a supply section (A ₁ ) and a winding section (B ₁ ) of a film (19), the supply section (A ₁ ) Supply roller at (1
A mechanism in which the peripheral speed of the plate cylinder (23) of the printer section (C ₁ ) and the take-up speed of the take-up roller (16) of the take-up section (B ₁ ) are sequentially increased with respect to the film supply speed of 3). And an expander roller (33) that stretches and removes wrinkles of the film (19) that has not yet been wound after printing on the winding unit (B ₁ ) and the film (19) when the film (19) is wound. (3) is provided on the take-up roller (16) side to elastically press and press the roller (36). 5. The expander roller (33) is a film (1
9. The wrapping film printing device according to claim 4, which is a heating roller for heating 9).