JPH0327895B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a printing plate using a resin liquid that is cured by irradiation with energy rays such as light.

(Conventional technology) Recently, when printing corrugated paperboard and newspapers, urethane-based photocurable liquid resin (product name: APR, manufacturer: Asahi Kasei Corporation), which is liquid in storage but hardens when exposed to ultraviolet irradiation, has been used recently. ) is used.

The production of this type of printing plate is carried out through the steps shown in FIGS. 7 to 11.

As an example, as shown in Figure 6, printing plate 1 used to print the mark "AB" on cardboard paper
(The mark appears as the reverse mark 9 on the surface of the printing plate.) A conventional method for manufacturing the mark will be explained.

Figure 7 shows negative film 3 used for producing printing plate 1.
A masking film 4 is shown in which a light-transmitting pattern 31 corresponding to the mark 9 is formed on the negative film 3, and the shaded area other than the pattern is a completely light-shielding surface.

The masking film 4 has patterns 31 corresponding to the translucent patterns 31 on the negative film 3.
It has a translucent pattern 41 with a slightly larger outline, and the other shaded areas are completely light-shielding surfaces.

Step a As shown in FIG. 8, a negative film 3 is placed on a transparent base plate 5, and a protective transparent film 6 that can be peeled off from the resin is placed on the negative film 3.
cover.

Step b: A frame 7 is provided on the outer periphery of the transparent film 6 so as to act as a dam against the liquid resin, and the entire transparent pattern 31 of the negative film 3 is surrounded by the frame 7. The inner transparent film 6 is filled with a photocurable liquid resin to form a photocurable liquid resin layer 2 (FIG. 8).

Step c: Place the transparent base film 11 on the liquid surface of the photocurable liquid resin layer 2, and
Cover masking film 4 on 1 (8th
figure).

Step d: As shown in FIG. 9, the ultraviolet lamps 51 and 5 are
1 to expose the liquid resin layer. The exposed portions of the masking film 4 and negative film 3 corresponding to the patterns 31 and 41 begin to harden, and the exposed portions at the end remain as liquid, and the cured resin portion on the negative film 3 side corresponds to the mark 9. The cured resin part on the side of the masking film 4 becomes the relief part 21.
The mount portion 22 is thickly connected to the mount portion 22 and serves as reinforcement.

Step e: The masking film 4 is removed and the base film 11 is exposed again for a short time from the outside as shown in FIG. 10 to thinly harden the entire upper surface of the resin liquid layer and form the base portion 23 integrally joined to the base film 11.

Step f: Remove the frame 7 and the transparent film 6, and collect the uncured resin liquid.

As shown in FIG. 11, the printing plate 1 is formed in which the relief part 21 is reinforced by the mount part 22, and the mount part 22 is connected to the base part 23 which covers almost the entire surface of the base film 11.

The printing plate 1 has a two-layer structure in which a base film 11 is bonded to a base part 23 by the adhesive force of resin and uniformly covers the base film 11. These are the relief part 21, the mount part 22, and the alignment mark 12.
The sheet is cut to an appropriate size, and as shown in FIG. 6, it is positioned and fixed on a transparent mount film 8 for a printing press, and is removably attached to the rotating cylinder of the printing press.

(Problems to be Solved by the Present Invention) Since photocurable liquid resins are expensive, it is required to use them as sparingly as possible.

However, printing plate 1 produced using the conventional procedure
Since the base portion 23 is formed on the entire surface of the base film 11, the amount of photocurable liquid resin used inevitably increases, resulting in a problem that the implementation cost of the method increases.

Further, in order to correctly position the printing plate 1 on the mounting film 8, the formation of the alignment mark 12 is essential. Therefore, conventionally, as shown in FIG.
2 and a translucent pattern 42 for forming a mounting part of the matching mark on the masking film 4.
A was formed, and the matching mark 12 was formed at the same time as the relief part 21, but as a result, the matching mark 12 was inevitably formed at the same height as the relief part 21.

Therefore, after the printing plate 1 is attached to the mounting film 8, the alignment mark 12 must be scraped to be lower than the relief portion 21 in order to prevent printing ink from adhering to the alignment mark 12.

The above operation is time-consuming, and if the relief portion 21 of the printing plate is complicated, the match mark 12 may be overlooked and left unscraped. Alternatively, problems such as the relief portion being scraped off by mistake occurred.

Further, as shown in FIG. 6, after positioning the printing plate on the mounting film, as a means for attaching it,
Conventionally, adhesive tape 13 is adhered around the printing plate while holding it down, thereby fixing the base of the printing plate and the mounting film, or double-sided adhesive tape is pasted on the back of the printing plate in advance and this is placed on the mounting film. I pressed it down and glued it.

However, with either method, if the adhesive strength of the adhesive tape is weakened, there is a risk that the printing plate will peel off from the mounting film due to the centrifugal force that acts on the printing plate during high-speed printing. When the surface is cleaned to remove ink and the plate is stored with the plate attached to the mounting film, the cleaning water enters the gap between the plate and the mounting film and remains, which may flow out during the next printing. , there was a risk of staining the printed surface. Attempts were also made to attach the mounting film and printing plate by integrally bonding them together using a high-frequency welder, but
The material of the mounting film is polyester.
Since the surface of the printing plate is uniformly covered with a base portion of urethane resin, high frequency welding could not be performed.

(Means for Solving the Problems) The present invention attempts to solve the above problems by using a specially designed masking film.

After performing the conventional steps a and b, c
When carrying out the process, the masking film 4, which is a feature of the present invention, is used and energy rays are irradiated.

The masking film 4 has an energy ray transmissive main pattern 44 having a slightly larger outline to match the pattern of the negative film, an energy ray semitransparent base part pattern 46 having an even larger outline than the main pattern, and The outer portion of the base pattern 45 has a shielding effect against energy rays to the extent that the resin liquid is not hardened.

(Operation and Effect) Transparent main pattern 44 of masking film 4
A mount portion 22 is formed correspondingly. A thinly extending base portion 23 is formed around the mount portion 22 in correspondence with the semi-transparent base portion pattern 45 .

Further outside the pattern for the base part, the passage of energy rays is blocked or only a small amount passes, and the liquid resin layer corresponding to that part is not cured, so that the base part is not formed.

On the other hand, the resin layer is cured in accordance with the negative film pattern to form a relief portion that is integrally connected to the mount portion.

Since the base portion, which extends from the periphery of the mount portion and has a wider area than the mount portion, is bonded to the base film as before, the stability of adhesion to the base film is improved.

After irradiation with energy beams, the uncured liquid resin is removed from the base film and recovered so that it can be reused. In the present invention, the liquid resin in the part corresponding to the outer part of the masking film base pattern is not irradiated with energy rays and is completely removed, leaving the base film exposed, so the amount of recovered resin increases. Resin consumption is saved. Since the relief part is supported by the mount part 22 which has a slightly larger outline than the mount part 22, there is no problem even if a relief part with a small ink adhesion area such as a thin line or dot is formed. Printing defects caused by twisting or chipping of the relief portion can be prevented.

The mount part and the base part can be formed at the same time by simply covering the masking film and irradiating the energy beam once.As with conventional methods, the mount part and the base part can be formed by covering the masking film and exposing it once, then removing the masking film and exposing it again to form the mount part and base part. Compared to a method in which the base portion is formed in a separate process, the manufacturing process is simplified and the efficiency of plate making can be improved.

Furthermore, by aligning a part of the semi-transparent pattern of the masking film with the alignment mark and making it the energy ray passage part, only a part of the energy ray reaches the resin layer due to the presence of the semi-blocking film, and the base A match mark can be formed on the film at a level lower than the mount section and at the same height as the base section.

In addition, since the printing plate is completed with the base film exposed around the base part, if this is positioned and placed on the mount film and the periphery is welded using a high frequency welder, the mount film and the base film of the printing plate are combined. If both are made of the same polyester material, they will be easily welded and bonded together, and the welding line can be formed around the outer periphery of the printing plate, so it can be easily attached between the printing plate and the mounting film as in the past. It also solves the problem of washing water entering.

(Example) The example describes a masking film for making a printing plate using the above-mentioned photocurable resin, but is not limited to this. It can also be applied to masking films for printing plate production using hardening resins.

Printing Plate FIG. 2 shows a state in which a printing plate 1 manufactured using the masking film of the present invention is attached at its edges to a mounting film 8 by high frequency welding 80.

The printing plate 1 has a mark 9 of "AB" embossed by relief portions 21, 21, similar to that described in the conventional example.

The relief part 21 is formed on a mount part 22 having a slightly larger outline than the relief part 21, and the mount part 22 is formed on a base part 23 surrounding it and having a wide area.

The base portion 23 is strongly adhered to the polyester base film 11 by the adhesive force of the resin itself or by the adhesive force of an adhesive applied to the base film if necessary, so that a relief is formed as shown in FIG. The portion 21, the mount portion 22, and the base portion 23 are integrally formed of photocurable resin. In the case of a printing plate for corrugated paper, the thickness h ₁ of the base portion 23 is approximately 2.0 mm.
It is preferable that the thickness h ₂ of the mount portion 22 is approximately 2.5 mm, and the thickness h ₃ of the relief portion 21 is approximately 2 mm.

In the printing plate 1, the base film 11 is exposed on the side where the base part 23 is not formed, and a positioning mark 12 is formed at the same height as the base part 22 in the exposed part of the base film. ing.

To fix the printing plate onto the mount film, use the matching marks on the printing plate to position it on the mount film, and then use a known portable high-frequency welding machine to move the exposed part of the base film of the printing plate onto the mount film. Weld and install as one piece.

Manufacturing process Next, the manufacturing process of the printing plate 1 will be explained.

Figure 1 shows negative film 3 used for making printing plate 1.
and masking film 4 are shown.

The masking film 4 has semi-blocking films 43 and 45 removably attached to both sides of a transparent film plate 42 using an adhesive.

The two half-blocking films 43 and 45 have different light-blocking rates; one half-blocking film 43 has a light blocking rate of 80%, and the other half-blocking film 45 has a light blocking rate of 90%. Therefore, the amount of light passing through both half-blocking films 43 and 45 is 2% of the total irradiation amount, and the photocurable resin will not be cured by this level of exposure.

The negative film 3 has a completely light-shielding surface, as shown by diagonal lines, except for the translucent pattern 31 corresponding to the mark 9. What should be noted here is that the negative film 3 does not have a transparent part that corresponds to the match mark 12 on the printing plate 1, and only the half-blocking film of the masking film described later corresponds to the match mark at the appropriate position. This is because a transparent portion 46a is formed.

On one half-blocking film 43, a translucent main pattern 44 is formed by cutting out a slightly larger outline than the translucent pattern 31 of the negative film 3, and on the other semi-blocking film 4.
5, a base pattern 46 is formed by cutting out an outline larger than the translucent main pattern 44 of the semi-blocking film 43. negative film 3
When viewed as a whole, the base pattern 46 outside the main pattern 44 is a semi-blocking pattern with a light blocking rate of 80%.

The transparent portion 4 corresponds to the alignment mark at the appropriate position of the semi-blocking film 43 on which the pattern 46 for the base portion is formed.
6a is formed by cutting out.

Each of the above-mentioned translucent patterns 44 and 46 and the translucent part 4
6a, patterns 44, 4 are formed on the semi-blocking films 43, 45 with a knife to a depth that reaches the transparent film plate 42;
It is formed by making a score line corresponding to 6 and peeling off the inside of the score line from the transparent film plate 42.

Incidentally, the masking film 4 is not limited to the above-mentioned one, and for example, one half-blocking film is peelably attached to the transparent film plate 42, and the other half-blocking film is stacked on top of the half-blocking film. A removable adhesive may also be used.

First step: As shown in FIG. 3, a negative film 3 is placed on a transparent base plate 5, and a transparent film 6 is placed over the negative film 3. Furthermore, transparent film 6
A substantially rectangular frame 7 is placed on the outer periphery of the frame 7.
A photocurable liquid resin is poured into the transparent film 6 to form a photocurable liquid resin layer 2 on the transparent film 6.

Second Step: A transparent base film 11 is placed on the upper surface of the photocurable liquid resin layer 2, and a masking film 4 is placed on top of the film 11. If necessary, a transparent adhesive (not shown) having good adhesion to the photocurable resin is applied to the lower surface of the transparent base film 11 in advance.

Third step As shown in FIG. 4, light from a light source 51 is applied from outside the transparent base plate 5 and masking film 4, and the photocurable resin is exposed for 380 to 400 seconds.

By exposure, the lower part of the resin layer corresponding to the main pattern 31 of the negative film 3 is hardened and becomes a relief part 21.

On the other hand, the cured state of the liquid resin layer 2 on the side of the masking film 4 is
Two-layer semi-blocking films 43 and 45 that constitute
In the part corresponding to the overlapping part of the patterns 44 and 46 formed in the above, the resin layer hardens thickly and becomes the mount part 22 that is integrally connected to the relief part 21, and also hangs over one of the semi-blocking films 43 and weakens. In the light-transmitting part on the other semi-blocking film 45, the upper part of the resin layer is thinly hardened in correspondence with the pattern 46 to form the mount part 22.
The base part 23 is connected to the base part 23.

The base portion 23 is made of adhesive due to the adhesiveness of the resin itself.
Alternatively, it is firmly bonded to the base film 11 with an adhesive applied to the base film 11 in advance. The order of exposure is to first start exposing the masking film 4 side, and when about 2/3 of the required exposure time has passed, start exposing the negative film 3 side. Stop exposure separately.

As described above, by exposing the masking film 4 side before the exposure from the negative film 3 side, the mount part 22 and base part 23, which serve as the base of the relief part 21, are formed before the relief part 21, Relief part 21
is stably formed integrally with the mount portion 22.

Although exposure from the negative film 3 side may be started after the exposure from the masking film 4 side is completed, in this case, a time loss occurs.

It goes without saying that the exposure time can be optimally determined depending on the thickness of the printing plate to be formed and the intensity of light.

When the shading rates of both half-blocking films are made to be different from each other, if the pattern for the base part is formed using a film with a high shading rate, the thickness of the base part can be made larger, and the pattern for the base part can be formed by using a film with a low shading rate. By forming this, a thin base part can be formed, and the thickness of the base part can be selected according to the thickness of the entire printing plate.

Fourth step: Masking film 4, frame 7, and transparent film 6 are removed, uncured liquid resin is collected, and printing plate 1 is completed.

If a masking film is formed by attaching two semi-blocking films with different energy ray blocking rates to a film plate, the thickness of the base part will vary depending on which half-blocking film the pattern for the base part is formed on. can be changed depending on conditions such as the overall thickness of the printing plate.

[Brief explanation of drawings]

Figure 1 is a perspective view of the negative film and masking film, Figure 2 is a perspective view of the printing plate attached to the mounting film, Figures 3, 4, and 5 are manufacturing process diagrams of the printing plate. Figure 6 is a perspective view of the conventional printing plate attached to the mounting film, Figure 7
The figure is a perspective view of a conventional masking film and negative film, and FIGS. 8, 9, 10, and 11 are manufacturing process diagrams of a conventional method. DESCRIPTION OF SYMBOLS 11... Transparent base film, 2... Photocurable liquid resin layer, 21... Relief part, 22... Mount part, 4... Masking film, 42... Transparent film, 43... Semi-blocking film, 45... …
Semi-blocking film.

Claims (1)

[Claims] 1 An energy ray curable resin liquid layer 2 that is cured by irradiation with energy rays such as light on a negative film 3
The upper surface of the resin liquid layer is covered with an energy ray transmissive base film 11, and the energy ray semitransparent films 43 and 45 are stacked to form a base film 11, which is slightly patterned in accordance with the pattern 31 of the negative film 3. Energy ray transparent main pattern 4 with large outline
4 and an energy ray semi-transparent base part pattern 46 having an even larger outline than the main pattern on the outside of the main pattern, and the outer part of the base part pattern 46 is formed by two energy ray semi-transparent films 4.
3 and 45, the masking film 4 has a shielding effect against energy rays to the extent that it does not harden the resin liquid.
A method for making a resin printing plate, in which a negative film 3 and a base film 11 are stacked on top of each other, and energy rays are irradiated from above and below to cure the resin liquid layer 2, and then uncured resin liquid is removed.