JPH0318188Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a plate cylinder for a flexo printing machine.

[Problems to be solved by conventional technology and ideas]

As shown in Fig. 3, a flexographic printing machine is a printing press in which printing ink is applied by an ink roller B to a rubber plate attached to the outer circumferential surface of a rotating plate cylinder A, and the plate cylinder A and impression cylinder For example, a paperboard D, which is a packaging material, is passed between the paperboard D and the paperboard D, and printing is applied to the surface of the paperboard D.

The rubber plate in this case can skillfully absorb the vibrations that occur when the printing press is running;
It suffers from severe wear and does not last long, and has problems in terms of pressure resistance and cost.

Therefore, it is conceivable to change this plate from one made of rubber to one made of resin. A plate made of resin is advantageous in terms of cost and pressure resistance, but on the other hand, the hardness of the resin is unique to the plate, causing uneven printing and vibrations when the printing press is driven. They couldn't absorb it, and in severe cases, they couldn't print it.

By the way, the resin plate 2 attached to the outer peripheral surface of the plate cylinder
is fixed to the plate cylinder by inserting its front and rear edges 2a, 2b into two front and rear notch grooves 3, 4 formed in the plate cylinder A as shown in FIG. As shown by 8 in FIG. 2, this problem can be solved by interposing a cushion material between the resin plate 2 mounted on the outer circumferential surface of the plate cylinder A and the outer circumferential surface of the plate cylinder A. However, in the case of FIG. 2, there is a drawback that the folded portion of the resin plate 2 tends to be slightly downward, and the printed pattern on the paperboard corresponding to that portion tends to be faded.

In the present invention, the front and rear edges 2a and 2b of a resin plate attached to the outer peripheral surface of the plate cylinder A are inserted into two front and rear notch grooves 3 and 4 formed on the plate cylinder A, and fixed. In a plate cylinder of the type in which a cushion material 8 is interposed between the resin plate 2 and the outer peripheral surface of the plate cylinder A,
The purpose of this is to prevent "printing blur" caused by the folded portion of the resin plate 2 near the notch grooves 3 and 4 of the plate cylinder A becoming slightly downward.

[Means to solve the problem]

In order to achieve this purpose, in the present invention, as shown in FIG. The arcuate surfaces of the protrusions 9a, 10a are attached to the outer circumferential surface of the cushion material 8 interposed between the resin plate 2 and the outer circumferential surface of the plate cylinder A. The resin plate 2 is made slightly lower so that when the cushion material 8 is compressed and deformed during printing, the arcuate surfaces of the protrusions 9a and 10a directly support the folded portion of the resin plate 2 by slightly lifting it.

[Effect]

In this way, in the case of Figure 2,
The folded area of the resin plate 2 near the notch grooves 3 and 4 of the plate cylinder A (i.e., the width W portion in FIG. 1) is slightly downward;
It is slightly lifted by the arc surface of.

〔Example〕

Embodiments of the present invention will be described based on the accompanying drawings.

An aluminum plate 1 is attached to the outermost layer of the roll-shaped plate cylinder A, and means for fixing the resin plate 2 is provided in a part thereof over the entire width of the plate cylinder A. The fixing means, as in the case of the conventional example shown in FIG. ) are provided facing each other in the width direction of the plate cylinder A, one edge 2a of the resin plate 2 wound around the outer peripheral surface of the plate cylinder A is placed in the notch groove 3, and the other edge 2b is notched. An example of this is the case where the holder 5 is inserted into the groove of the holder 5 inserted into the groove 4 and fixed (see FIG. 1). In this case, when the holder 5 is rotated counterclockwise in FIGS. 1 and 2 within the notched groove 4, the resin plate 2 is stretched taut on the outer circumferential surface of the plate cylinder A. The flat surface formed on the outer peripheral surface of the holder 5 engages with the navel-shaped protrusion 7 that protrudes into the chamber in which the holder 5 is fitted due to the elasticity of the spring 6, and the holder 5 Notch groove 4
The resin plate 2 is held on the outer peripheral surface of the plate cylinder A under tension.

A cushion material 8 is interposed between the outer peripheral surface of the plate cylinder A and the resin plate 2 mounted on the outside thereof, except for the vicinity of the notch grooves 3 and 4.

The cushion material 8 can be made of sponge, for example, and in order to fix it to the outer peripheral surface of the plate cylinder A,
For example, double-sided tape may be used.

In this way, when the cushion material 8 is interposed between the outer peripheral surface of the plate cylinder A and the resin plate 2, the hardness of the resin plate 2 is alleviated by the cushion material 8, and the appropriate elasticity necessary for printing is maintained. There is no sagging or uneven printing, and the finish is extremely good.

Then, as shown in FIG. 1, the backing plates 9 and 10 are attached to the entrances of the notch grooves 3 and 4 for inserting and fixing both end edges 2a and 2b of the resin plate 2, and the backing plates 9 and 10 are placed facing each other. Protrusions 9a, 10a having a similar shape to the outer peripheral surface of the plate cylinder A are provided on the front and rear edges, and the protrusions 9a, 10a are provided on the front and rear edges.
The arc surface of the cushion material 8 is made slightly lower than the outer peripheral surface of the cushion material 8 during printing.
During compressive deformation, the arcuate surfaces of the protrusions 9a and 10a directly support the folded portion of the resin plate 2 so as to slightly lift it. In this case, in the case of FIG. 2, the part near the fold of the resin plate 2 (i.e., the width W part in FIG. 1) becomes slightly downward.
The printed pattern on the surface of the paperboard corresponding to that part will be slightly faded, but as shown in FIG. If you pay to
The above drawbacks can be eliminated and clear printing can be obtained.

Note that using a resin plate instead of a rubber plate is advantageous in terms of cost and pressure resistance. This is alleviated by the cushion material 8 interposed between the cylinders, so that uneven printing and vibrations of the plate cylinder during driving are less likely to occur.

Further, by interposing the cushion material 8 between the outer peripheral surface of the plate cylinder A and the resin plate 2, the resin plate can be made very thin. By the way, its thickness is
It has been confirmed through experimental research that sufficiently good results can be obtained even with a plate thickness of 1.7 mm or less, which is thinner than the plate thickness without intervening cushioning material.

If the resin plate is made of a photosensitive material, it can be made using a printing technique.
The process of making plates is very simple, and large quantities of the same plate can be made.

According to the present invention, it is completely prevented that the folded area of the resin plate near the entrance of the notch groove formed on the plate cylinder tends to fall downward, so that the printed pattern on the surface of the paperboard corresponding to that area becomes blurred. It has the effect of never happening.

It should be noted that the present invention can of course be applied not only to the case of using a plate fixed to the plate cylinder by the fixing means explained in the above embodiment, but also to the case of using a sleeve-shaped plate that is fitted from the side of the plate cylinder. .

[Brief explanation of the drawing]

FIG. 1 of the accompanying drawings is an enlarged longitudinal sectional side view showing an embodiment of a printing press cylinder according to the present invention, showing only the vicinity of the fixing part of the resin plate, and FIG. 2 is an enlarged longitudinal sectional side view showing a conventional example. FIG. 3 is a schematic diagram showing the principle of a flexo printing machine. 2... Resin plate, 2a, 2b... Edge portion, 3, 4
...Notch groove, 5...Holder, 7...Protrusion, 8...
...Cushion material, 9,10...Packing plate, 9a,
10a...Protrusion, A...Print cylinder, B...Ink roller, C...Impression cylinder, D...Paperboard.

Claims (1)

[Scope of utility model registration request] Both front and rear edges of the resin plate attached to the outer circumferential surface of the half cylinder are inserted and fixed into the two front and rear notch grooves formed on the plate cylinder, and the space between the resin plate and the outer circumferential surface of the plate cylinder is fixed. In a plate cylinder for a printing press in which a cushioning material is interposed, a patch plate is provided with a protrusion having an arcuate surface similar to the outer peripheral surface of the plate cylinder at the entrance of the notch groove where the folded part of the resin plate is located. The arcuate surface of the protrusion is made slightly lower than the outer peripheral surface of the cushion material, so that when the cushion material is compressed and deformed during printing, the arcuate surface of the protrusion slightly lifts the folded area of the resin plate. A printing press cylinder characterized by direct support.