JPH0210408B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in printing presses.

[Conventional technology]

For example, as shown in FIG. 1, a conventional general plate printing machine attaches a film original 3 to a glass plate 2 provided on a holder body 1, and then attaches a film original 3 to a plate 5 of a support 4.
A printing plate 6 is provided, and after the film original 3 and the printing plate 6 are brought together, exposure and printing is performed in a vacuum state.

In addition, parts other than the image portion of the film original 3 attached to the glass plate 2 are shielded from light by a light shielding film 7, and a plurality of images A, B, C, D, E, and F are sequentially exposed.

However, in the same structure, the peripheral area shielded from light by the light shielding film 7 remains as an unexposed area, so it is necessary to re-expose the area using a separate printing frame and perform printing.

However, this structure has the drawback that when re-exposing the unexposed portion, it is necessary to accurately shield the exposed film document portion 3 from light with a light shielding film, resulting in poor workability.

Therefore, other printing presses having structures as shown in FIGS. 3 and 4 have been used in the past. That is, an original film 13 is supported on a glass plate 12 supported on a printing press holder 11, a printing plate 15 is supported on the upper surface of a support 14, and a glass plate 12 is placed on the glass plate 12 on the opposite side from the light source 16. The light shielding film 17 is configured to move from the four sides near the outer periphery to the center of the glass plate 12.

For example, when six patterns A, B, C, D, E, and F are sequentially exposed as shown in FIG.
The four light-shielding films 17 are moved as necessary so that the light-shielding films 17 cover areas other than those to be exposed and printed.

By the way, in the same structure, the patterns A, B, C,
D, E, F and the surrounding area 1S are exposed and printed,
It is the portion 19 larger than the glass plate 12 that is not exposed and printed.

Therefore, when the unexposed portion is burned off, one end of the image area light-shielding paper only needs to be located between the unexposed portion 19 and the pattern, and accuracy is not required and work efficiency is improved.

However, since it is necessary to place the four light-shielding films 17 between the glass plate 12 and the support plate 14 and create a vacuum state, the light-shielding films cannot be made thicker than a predetermined thickness, and the light-shielding films have no tension. The glue of the tape pasted on the glass plate 12 to support the original film 13 adheres to the light-shielding film 17, and the light-shielding film tends to engage with the end face of the tape, so that the light-shielding film 17 is easily engaged with the end surface of the tape with a small force.
The disadvantage is that it does not move back and forth.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to provide a plate printing machine that has a relatively simple structure, can move a light-shielding film back and forth favorably, and has good workability.

〔structure〕

The present invention will be explained below with reference to FIGS. 5 to 10. In the figure, reference numeral 21 denotes a printing press support plate which is configured to be tiltable. 22 is a printing plate supported on the support plate 21 of the printing press, and 23 is a document holder for the printing press having a rubber gasket 24 for vacuum on the outer periphery, which moves back and forth with respect to the support plate of the printing plate. It is configured so that it can be tilted. Reference numeral 26 denotes a glass support frame having a vacuum rubber gasket 27 on its outer periphery, and is configured to move back and forth about 1.5 cm relative to the document holder 23. 25 is a glass support frame 26
It is a support arm for moving back and forth, and is configured to be operated by, for example, an air cylinder. 28 is a gear for moving the support arm 25 back and forth, 29 is a shaft for operating the gear 28, 30 is a translucent glass plate supported by the glass support frame 26, and 31 is a light source, for example. A 2 kilowatt high pressure discharge lamp is used.

32 is a drive ring for moving the light-shielding film back and forth from the four sides near the outer periphery of the document holder 23 toward the center of the glass support frame 26, as shown in FIG. 7; 33 is a light-shielding film mounting band supported on the drive ring 32; Reference numeral 34 denotes a light-shielding film supported by the light-shielding film attachment band 33, which is located on the glass plate on the opposite side from the light source 31, and which moves back and forth from the four sides near the outer periphery of the document holder 23 toward the center of the glass support frame 26. , it is constructed to block light where necessary.

Reference numeral 35 denotes a light shielding member supported at the tip of the light shielding film 34, which can pull the light shielding film 34 and clearly distinguish the exposed portion from the unexposed portion during exposure. The light shielding body 35 is made of metal foil having a thickness of about 0.03 mm, for example.

Next, the operation of the plate printing machine with the above structure will be explained.

(1) First, place the printing plate 2 on the surface of the supporting plate 21 which is laid down horizontally.
A document film 40 is placed on the surface of the glass plate 30 of the document holder 23 which is laid down horizontally and fixed with tape 39.

At this stage of the work, the light-shielding film 34 is stored in an empty space near the periphery of the document holder 23.

(2) Next, set up the support plate 21 and document holder 23.

At this stage, the glass support frame 26 is attached to the document holder 2.
3, the light shielding film 34 is located approximately 1.5 cm rearward from the exposure printing time, and the light shielding film 34 protrudes to cover the area other than the exposed portion.

After the light shielding film 34 covers the necessary parts, the glass plate 30 supported by the glass support frame 26 is covered with the light shielding film 3.
Move forward to position 4.

Note that the back and forth movements of the light shielding film 34 and the back and forth movements of the glass support frame 26 are configured to be synchronized.

(3) After this, the document holder 23 is brought close to the support plate 21, and after creating a vacuum between the two, exposure printing is performed using the light source 31.

(4) If pattern A shown in FIG. 9 is exposed and printed as described in (1) to (3) above, patterns B to F shown in FIG. 8 are sequentially exposed and printed as follows.

If pattern B is exposed and printed first, the support plate 21
The original holder 23 is moved back from the original holder 23 to release the vacuum, and the glass support frame 2 is further removed from the original holder 23.
6 is moved back about 1.5 cm, and as shown in FIG. 10, the patterns other than B are covered with three light-shielding films 34 and the printing operation is performed. Thereafter, the printing work is sequentially performed for the patterns C to F in the same manner.

〔Effect of the invention〕

As described above, the present invention is located on the surface opposite to the light source of a glass plate supported on a manuscript holder of a plate printing machine, and is movable back and forth from the four sides near the outer periphery of the manuscript holder toward the center of the glass support frame. The plate holder is provided with a light-shielding film so that the plate holder is movable back and forth with respect to the plate support, and the glass plate is configured to be movable back and forth with respect to the document holder.
As mentioned above, when the light-shielding film is moved back and forth, the glass plate retreats from the original holder, and the light-shielding film does not come into close contact with the tape or original film on the glass plate as in the conventional structure, but rather It moves well back and forth on the board and can block light where necessary.

Also, as shown above, the patterns A, B, C, D, E, F
When exposed and printed in sequence, the portion 3 larger than the glass plate 30 is not printed, as shown in FIG.
7, and when burning off the unexposed area, the tip of the light-shielding film only needs to be located between the unexposed area and the pattern, and precision is not required, which has the advantage of greatly improving workability and is of great utility value.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a manuscript holder in a conventional printing press, Fig. 2 is a plan view showing the exposure and printing sequence of the printing plate shown in Fig. 1, and Fig. 3 is a manuscript holder of another conventional printing plate. FIG. 4 is a plan view showing the exposure and printing sequence of the printing plate machine in FIG. FIG. 5 shows the state when the light-shielding film protrudes and enters, and FIG. 6 shows the state when exposing and printing. FIG. 7 is a plan view showing the relationship between the glass plate, drive ring, light-shielding film attachment band, and light-shielding film in FIGS. 5 and 6, and FIGS. 8 to 10 are reprints of FIGS. 5 and 6. FIG. 2 is a plan view showing the exposure/printing order of the machine. 21... plate printing machine support plate, 22... printing plate, 23...
...Original holder, 26...Glass support frame, 30...
Glass plate, 31... light source, 34... light shielding film.

Claims (1)

[Claims] 1. The original film 40 and the printing plate 2 are placed between the printing press support plate 21 and the glass plate 30 provided on the original holder 23.
2 and after evacuating the inside, remove the glass plate 30.
In a plate printing machine that exposes and prints using a light source 31 provided on the front side of the plate, the plate is located on the surface opposite to the light source 31 of the glass plate 30 supported on the document holder 23 of the plate plate, and near the outer periphery of the document holder 23. Glass frame 2 from all sides of
The light shielding film 34 moves back and forth toward the center of 6.
In addition, the original holder 23 is configured to be movable back and forth with respect to the printing press support plate 21, and the original holder 2
3, the glass plate 30 is configured to be movable back and forth, and when moving the light-shielding film 34 back and forth, the glass plate 30 retreats from the original holder 23, and during exposure printing, the glass plate 30 moves back and forth from the light-shielding film 34.
A plate printing machine characterized by being configured to move forward up to 4.