JPH0119140B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for contact printing printing plates.

When printing plates in close contact, a light-transmitting original and a photosensitive plate material such as a PS plate are placed one on top of the other in an airtight packing frame made of rubber or the like provided around a hard transparent plate such as a glass plate, and then A sealed portion is formed inside the flexible sheet by stacking the flexible sheets, and the sealed portion is evacuated using an evacuation means such as a vacuum pump, and the original and the photosensitive plate are separated between the glass plate and the rubber plate. A method in which flexible sheets such as sheets are brought into close contact is known.

In particular, in order to prevent relative misalignment between the original and the plate material, a plurality of positioning pins are fixed to a glass plate, and a transparent original with holes drilled in advance according to the positions of the positioning pins is pasted on the glass plate. A method is used in which a plate material with holes drilled in advance in accordance with the positions of positioning pins is aligned on a transparent original. At this time, in order to perform highly accurate positioning, it is better that the difference between the outer diameter of the pin and the inner diameter of the hole in the original or plate material is small. That is, since the dimensional difference between the positioning pin and the hole in the plate material directly affects the printing position accuracy, it is better that the difference be as small as possible in order to improve the accuracy. However, if the difference is made small in this way, it becomes difficult to insert the photosensitive plate material into the pin and to take it out from the pin, resulting in poor workability.

Conventionally, the following method has generally been used to attach and remove a plate in such a plate contact printing apparatus.

First, when attaching the plate material to the positioning pins,
A pin was inserted into the hole in the photosensitive plate using a presser bar fixed vertically, but although the hole and pin were mostly aligned, the center of the hole and the center of the pin were slightly misaligned. When the presser bar is lowered (for example, in the state shown in FIG. 7a), the plate material needs to shift slightly in the horizontal direction against the vertical pressing force of the presser bar. However, since the presser bar is fixed, it does not allow the plate material to shift in the horizontal direction, causing problems such as deformation of the holes in the plate material. This drawback becomes even more of a disadvantage when the holes in the plate material are also used in other processes.

Next, when taking out the plate material from the positioning pin, as shown in FIG. 10c, for example, the suction cup 30
The plate material 12 was lifted and taken out using negative pressure. However, according to this method, the suction cup 30 performs the suction lifting at a location away from the pin 11, and the frictional force between the pin 11 and the hole in the plate material 12 makes it impossible to perform a good lifting. 12
Combined with the lack of rigidity, flexure occurs as shown in the figure.

In order to overcome the above drawbacks, it is conceivable to install multiple suction cups around the pin and lift the plate horizontally, but usually the pins are located near the corners of the plate, and the suction cups are placed close to each other. Difficulty lifting while maintaining balance.

In view of the drawbacks associated with the conventional contact printing method described above, the present invention enables easy and accurate attachment and detachment of a photosensitive plate material to a high-precision positioning pin without deforming or damaging holes corresponding to the pins formed in the plate material. The purpose of the present invention is to provide a contact printing method for printing plates that can be performed in a manner that allows the printing of printing plates to be carried out in a manner similar to that described above.

According to the invention, the vertically extending presser bar is
Loosely held in a vertically movable holder, and
The loose hole in the holder allows the presser bar to move in the horizontal direction. Therefore, the presser bar presses the plate material and allows the plate material to be displaced in the horizontal direction when the pin is inserted into the hole in the plate material. The second part of this invention
According to this embodiment, the presser bar may be supported on the holder via an elastic material that has the same function as the loose hole.

Furthermore, according to the method of extracting the photosensitive plate material from the high-precision positioning pin of the present invention, in addition to the above-mentioned suction cup, a small-diameter suction cup that can move coaxially and perpendicularly to the positioning pin is provided. By making the suction and lifting position of the surrounding plate material substantially the same as the suction and lifting position of the plate material by other suction cups, extraction from the pin can be easily achieved.

The position of the presser bar when it presses one end of the photosensitive plate material as described above must remain unchanged until the flexible sheet unfolds and presses the other end of the photosensitive plate material. . In other words, photosensitive printing plates generally have curls, and when the flexible sheet is unfolded, a force that urges the printing plate in the unfolding direction is applied, so the flexible sheet unfolds and the printing plate is exposed. The presser bar must press and hold the plate material until the sheet is pressed down to prevent the plate material from coming off the pins.

The contact printing process of the plate material in the present invention will be summarized.

(1) The photosensitive plate is sucked by a suction cup and transported onto the exposure section (glass plate). (2) At the position where the hole formed in the photosensitive plate enters the pin, the suction is released and the plate is placed on the original. (3) Lower the presser bar around the hole in the plate and push the plate into the pin. The pressing state of the presser bar is
The flexible sheet unfolds and is maintained until it presses the opposite side of the plate. (4) After exposure, the flexible sheet returns to its original position and covers the part of the plate near the hole in the plate. A suction cup placed coaxially with the pin picks up the plate, and another suction cup picks up the other part of the plate while lifting and ejecting the plate.

First regarding the contact printing apparatus for plate materials according to the present invention
A detailed explanation will be given based on the embodiments illustrated in FIGS.

FIG. 1 is a plan view of a plate material contact printing apparatus which is an embodiment of the present invention. A rigid transparent body 2, for example, a glass plate (hereinafter referred to as glass plate 2) is mounted on the fixed base 1.
is included. An airtight gasket 14 is provided around the glass plate 2 on the fixing base 1, and an exhaust port 15 for vacuum suction is provided within the gastight gasket 14. A plurality of (two) positioning pins 11 are fixed to the glass plate, and a transparent original 13, which will be described later and has holes drilled in advance in accordance with the positions of the positioning pins 11, is pasted on the glass plate 2. On top of that, a photosensitive plate 12 with holes drilled in advance in accordance with the positions of the positioning pins 11 is conveyed with the photosensitive surface facing downward by a suction cup 20, which will be described later, and is inserted into the positioning pins 11 and aligned and placed on the transparent original 13. place A pair of sliding holding plates 3 on which a guide roller 4 and a presser roller 5 are pivotally fixed are vertically provided on both sides of the fixed base 1.

2 is a sectional view taken along the line ``-'' of FIG. 1 in the direction of the arrow, and FIG. 3 is a sectional view taken along the line ``-'' of FIG. 1 in the direction of the arrow. The lower ends of the sliding holding plates 3 are each connected to an endless chain 7 driven by a drive source 6 at a connecting part 8, and the fixed base 1
A pair of guides 9 extending parallel to the fixed base 1 on both sides of the
The sliding holding plate 3 slides along. Further, one end of a flexible sheet, for example, a rubber sheet 10, is fixed to a fixed base 1, and by sliding a holding plate 3, a guide roll 4
As the rubber sheet 10 rotates, the rubber sheet 10 covers the glass plate 2. At this time, the presser roller 5 presses and moves on the rubber sheet 10 sequentially covering the glass plate 2 by the guide roll 4, and presses the rubber sheet 10,
Promotes close contact between the photosensitive plate material 12 and the transparent original 13.

4 and 5 are cross-sectional views corresponding to FIGS. 2 and 3, respectively, and show a state in which the holding plate 3 in FIG. 1 has completed moving to the left in the figure. The photosensitive plate material 12 and the transparent original 13 aligned on the glass plate 2 by the pins 11 are covered with a rubber sheet 10. An airtight packing 14 is provided around the glass plate 2, and the space formed by the airtight packing 14 and the rubber sheet 10 is evacuated through an exhaust hole 15, and the transparent original 13 and the photosensitive plate material 12 are are placed in close contact with each other and exposed to light from the light source 16.
After exposure, the rubber sheet 10 returns to its original position, and the photosensitive plate material 12 is moved by suction cups 30 and 31, which will be described later.
Lift up and eject.

In this embodiment, the other end of the rubber sheet 10 is suspended along the fixed base 1 via the fixed roller 18 by the weight 17, but from the viewpoint of space, it is wrapped around the guide roller 4. The rubber sheet may be spread out on the glass plate 2 by the rotation of the roller 4. In this case, it is preferable that the axis of the guide roller 4 is biased so that the rubber sheet 10 is always spread out on the glass plate 2 under tension. For example, as disclosed in Japanese Unexamined Patent Publication No. 52-29739, the roller 4 may be constantly applied with rotational force in the clockwise direction in the figure.

Next, a method for inserting the photosensitive plate material 12 according to the present invention into the positioning pin 11 and extracting it from the pin 11 will be described.

FIG. 6 is a schematic cross-sectional view showing a state in which the photosensitive plate material 12 is suctioned and conveyed, and a plurality of suction cups 2
0 is fixed to a frame (not shown), and the frame is movable horizontally on a fixed base 1.
The suction cup 20 is movable up and down by a conventional cylinder mechanism, and the photosensitive plate material 12 is placed on the positioning pin 1.
1, the suction is released and the photosensitive plate material 12 is placed on the transparent original 13.

FIGS. 7a and 7b show cross-sectional views of the various mechanisms used to push the photosensitive plate material 12 onto the pins 11. FIG. 7th
As shown in Figure a, the presser bar 21 is loosely held by a vertically movable holder 22 through a loose hole 22'. The lower end of the leg of the presser bar 21 is lowered as the presser bar holder is lowered to a position where it can come into contact with the periphery of the hole 12' formed in the photosensitive plate material 12. As shown in FIG. 7b, after the holder 22 is lowered below a certain position, the stopper portion 21' of the presser bar 21 is separated from the holder, and the presser bar 21 can move freely. That is, as shown in FIG. 8, even if the hole 12' of the photosensitive plate material 12 and the positioning pin 11 are slightly misaligned, the presser bar 21 is held loosely with respect to the holder 22, so the presser bar 21 is held loosely with respect to the holder 22. The downward force of the bar 21 due to its own weight, combined with the free movement of the presser bar 21 in the horizontal direction, causes the plate material 12 to
Since both the presser bar 21 and the presser bar 21 are shifted in the direction of arrow A,
The pin 11 can be inserted accurately into the hole 12' without damaging the plate material 12 or applying unnecessary loads.

Further, if necessary, a spring or the like may be provided between the lower surface of the holder 22 and the presser bar leg to negatively bias the presser bar 21 downward.

Furthermore, as shown in FIG. 9, the presser bar 21 may be supported by an elastic member 25 so as to be able to move in the lateral direction so as to have the same effect as the loose hole 22'. Note that it goes without saying that the presser bar 21 is slidable in the vertical direction with respect to the elastic member 25.

The photosensitive plate material 12 generally has curls, and when the rubber sheet 10 is rolled out on the plate material 12, a force that pushes the plate material 12 in the lateral direction (in the direction of movement of the rollers 4 and 5) acts, The engaged pin 11 and hole 12' may become disengaged. Therefore, as shown in FIG. 7b, the presser bar 21 needs to maintain the above-mentioned pressing position until the presser roller 5 reaches the position where it presses the other end of the plate material 12 via the rubber sheet 10. . Therefore, in the device of the present invention, after the presser roller 5 reaches this position, the holding plate 2
2 rises, releases the presser by the presser bar 21,
The rubber sheet 10 is made to be able to cover the plate material 12.

Next, a mechanism for discharging the plate material 12 after exposure is completed will be described with reference to FIGS. 10a, b, and c.

After the exposure is completed, the rubber sheet 10 returns from the state shown in FIG. 5 to the state shown in FIG. The plate material 12 is attracted by negative pressure by the plates 30 and 31. In the present invention, by adding a small-diameter suction cup 31 at a position corresponding to the positioning pin 11, the pin 11 can be attached to the hole in the plate material.
2', the other suction cups 30 hold the plate material 1.
The plate material 12 can be suctioned and raised at the same height as that at which the plate material 2 is suctioned and raised, and therefore the entire plate material 12 can be raised horizontally compared to the case of FIG. 10c. As a result, the plate material 12 can be pulled out from the pin 11 without deforming the plate material 12 or damaging the hole 12' of the plate material 12. It is an essential condition that the hole 12' is not deformed or damaged when it is used in other processes.

In the present invention, in order to suppress the relative misalignment between the photosensitive plate material 12 and the transparent original 13 as much as possible, the difference between the inner diameter of the hole 12' of the plate material 12 and the outer diameter of the pin 11 is made as small as possible. It has been made smaller. Therefore, in the process where the plate material 12 is rising along the pin 11,
Since the difference between the two is small, the suction cup 31 can reliably suction up the vicinity of the hole forming portion of the plate. After the plate material 12 is removed from the pin 11, the suction cup 31
Since outside air will be sucked in through the holes 12' in the plate, a valve mechanism to prevent this will be provided, or the suction systems for the suction cups 30 and 31 will be made independent so that the suction cups 31 can absorb the outside air. suction cup 3
The inhalation effect of 0 may not be affected.

Next, the structure of the rubber sheet 10 according to the present invention will be explained. In the present invention, the difference between the inner diameter of the hole formed in the photosensitive plate material 12 and the outer diameter of the positioning pin 11 is reduced as much as possible, and the original 13 of the plate material 12 is
Because it virtually eliminates the discrepancy between
The axial length of the positioning pin 11 is determined by chamfering the top or making it hemispherical so that the positioning pin 11 is connected to the plate material 12, the hole, and the pin 11.
facilitates engagement with the Therefore, in order to ensure the effective length of the pin 11, it is necessary to increase the axial length of the pin 11.

FIG. 11a is a partial cross-sectional view of a case where a conventional rubber sheet 10' is used as a high-precision positioning pin 11, and FIG. FIG. When using the conventional rubber sheet 10', the rubber sheet 10' near the positioning pin 11
has a substantially conical shape, which has the disadvantage that it is difficult to hold down the photosensitive plate material 12 near the positioning pin 11. However, when the rubber sheet 10 according to the present invention is used, the position corresponding to the pin 11 By forming the lid portion 10a having a rectangular cross section, the plate material portion in the vicinity of the positioning pin 11 is held securely.
That is, by increasing the thickness W of the vertical portion of the lid portion 10a, the rigidity of that portion is obtained, thereby ensuring the pressing of the portion of the plate material 12 near the pin 11. The height h of the lid part 10a is normally set so that the horizontal part of the lid part is at the height of the top of the pin 11.

FIG. 12 is a sectional view showing another embodiment of the rubber sheet 10 according to the present invention, in which the top of the lid portion 10b has a semicircular cross section, and serves to hold down the plate material 12 near the pin 11. Needless to say, this is what we do.

The presser roller 5 presses the rubber sheet 10 spread out by the guide roller 4. The lid parts 10a and 10b are made of rubber sheet 1
4, the cover portions 10a, 10b of the presser roller 5
An annular groove 5a is formed at a position corresponding to , to avoid collision with the lid portions 10a and 10b.

Next, the fixed position of the rubber sheet 10 according to the present invention and the positional relationship when the presser roller 5 is retreated will be explained.

In the state shown in FIG. 3 (the state before the rubber sheet is developed), the pressure of the presser roller 5 on the rubber sheet 10 must be released. That is, even when the press roller 5 moves from the state shown in FIG. 5 to the state shown in FIG. Receives an urging force in the direction of movement. On the other hand, since one end of the rubber sheet 10 is fixed to the fixed base 1, the rubber sheet 10 is deformed and sagged between the press roller 5 and one end of the rubber sheet 10 due to the urging force from the press roller 5. Therefore, in the state shown in FIG. 3, it is necessary to release the pressure of the presser roller 5 on the rubber sheet 10 and remove the slack in the rubber sheet 10 by the weight of the weight 17.

FIG. 13 is a sectional view of a main part showing the state of FIG. 3 in more detail. In the present invention, the rubber sheet 1
0 is fixed at a position lower than the upper surface of the airtight gasket 14 and the fixing base 1. Presser roller 5
The shaft 30 slides on the holding plate 3 via a bearing 31.
It is rotatably supported by a bearing holder 32 fixed to. The bearing holder 32 is U-shaped, and the axis 30 of the presser roller 5 is vertically movable within the bearing holder 32 via the bearing 31.

Therefore, when the sliding holding plate 3 moves in the direction of the arrow B in FIG. . Further, when the sliding holding plate 3 moves in the direction of arrow C in FIG. It falls slightly onto the bottom surface 32a of the bearing holder 32. The falling distance is
The thickness is within the thickness range of the rubber sheet 10.

As described above, by attaching one end of the rubber sheet 10 low, the presser roller 5 only falls to the position where it stops by the bearing holder 32, and the falling distance is also within the thickness range of the rubber sheet 10. Therefore, it is very short and does not give a large impact to the bearing 31 or holder 32. This effect becomes even more pronounced when driving at high speeds. In addition, if necessary, the bottom part 3 of the bearing holder 32 may be
By providing a cushioning material to 2a, the presser roller 5
It is also possible to further soften the impact caused by a fall.

[Brief explanation of drawings]

1 is a plan view of a plate material contact printing apparatus which is an embodiment of the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1 in the direction of the arrow, and FIG. 4 and 5 are sectional views in another operating state corresponding to FIGS. 2 and 3, and FIG. A schematic cross-sectional view showing the state in which the
b is a cross-sectional view of each mechanism used to push the photosensitive plate material into the register pin, FIG. 8 is a cross-sectional view showing the state in which the presser bar presses the photosensitive plate material into the pin, and FIG. Cross-sectional view showing the embodiment, Figures 10a and b
10 is a sectional view of each mechanism used to extract the photosensitive plate material from the pin, FIG. 10c is a sectional view of a conventional extraction mechanism, and FIG. FIG. 11b is a cross-sectional view of a main part of a rubber sheet according to the present invention, FIG. 12 is a cross-sectional view of a main part showing another embodiment of a rubber sheet according to the present invention, and FIG. 13 is a cross-sectional view of a main part of a rubber sheet according to the present invention. FIG. 3 is a sectional view of a main part showing a fixing position and a presser roller. 1... Fixed stand, 2... Hard transparent body (glass plate),
3...Sliding holding plate, 4...Guide roller, 5...
Presser roller, 7... Endless chain, 9... Guide, 10... Flexible sheet (rubber sheet), 11
...Register pin, 12...Photosensitive plate material, 13
...Transparent manuscript, 14...Airtight packing, 15...
...Exhaust hole, 16...Light source, 20...Suction cup, 21
... Presser bar, 22 ... Holder, 22' ... Loose hole, 25 ... Elastic material, 30, 31 ... Suction cup.

Claims (1)

[Claims] 1. A transparent document having holes formed for engaging with the positioning pins is inserted into at least two positioning pins fixed on a hard transparent body, and the transparent original is placed on the hard transparent body, and the positioning is performed. A flexible sheet that presses and covers the transparent original and the photosensitive plate by aligning and placing a photosensitive plate having holes for engaging with the pins on the transparent original, and expanding the sheet. In a plate contact printing method in which the photosensitive plate and the transparent original are brought into close contact with each other for exposure by reducing the pressure between the transparent plate and the hard transparent body, A plate material pressing means which can be pressed and is movable in the horizontal direction engages the hole and the positioning pin while allowing the horizontal displacement of the photosensitive plate material. When the flexible sheet is unfolded, the flexible sheet is maintained until it presses the other end of the photosensitive plate material, and when the photosensitive plate material is removed from the positioning pin after exposure, the area around the positioning pin is A method for contact printing a plate material, characterized in that the pin is adsorbed coaxially with the pin and taken out.