JPS61258753A - Endless plate joining for flexographic printing - Google Patents

Abstract

PURPOSE:To enable easy and economical joining of a plate in an endless manner with an adequate accuracy by cutting a flexo-sheet plate on a plate cylinder or on a sleeve. CONSTITUTION:A pair of spacers 2a and 2b for positioning which have a thickness about equal to that of a flexo-sheet plate is provided on a circumferential surface of a plate cylinder 1 at both ends in the axial direction of the cylinder. The head 3a of the flexo-sheet plate 3 is detachably attached between the above spacers, and further on the surface of 3a an adhesive tape 4 is attached to cover the plate to be cut. Then, the head 3a of the sheet plate is cut along a straight line C which connects points A and B on the spacers together with the adhesive tape 4. Then, the circumferential surface of the plate cylinder 1 is wrapped and pasted with the sheet plate 3, and at the same time, the head 3a is removed and the tail 3b of the sheet plate 3 is detachably attached where the head was removed, and the adhesive tape 4 is attached to the tail 3b. The tail 3b is cut along the straight line C together with the adhesive tape, and subsequently, the head 3a is re-attached to finish the plate joining.

Description

[Detailed Description of the Invention] The present invention relates to a method of endlessly splicing a flexo sheet plate onto a plate cylinder or sleeve in flexo printing, and more specifically, it relates to a method for endlessly splicing a flexo sheet plate onto a plate cylinder or sleeve in flexographic printing, and more specifically, it can easily and inexpensively achieve extremely high splicing accuracy. This article relates to a method for splicing flexo sheet plates.

The conventional explanation will be explained. Traditionally,
In flexo printing, the method of endlessly splicing a flexo sheet plate onto a plate cylinder or sleeve is as follows:
After cutting the flexo sheet plate in advance on a flat table so that its length is equal to the circumferential length of the plate cylinder or sleeve, this flexo sheet plate is attached to the circumference of the plate cylinder or sleeve using double-sided adhesive tape, etc. The method is adopted. In this case, calculate the cutting length of the flexo sheet by taking into account the thickness of the flexo sheet and double-sided adhesive tape, and use a ballpoint pen or pencil to draw the cutting line at the cut point of the flexo sheet according to this cutting length. The flexographic sheet plate is then cut along these lines using a cutting board and a cutter knife.

However, in the above method, the flexo sheet plate is cut to a predetermined size on a flat table in advance and then attached to the plate cylinder or sleeve, so the thickness of the flexo sheet plate may vary and the thickness of the double-sided adhesive tape may Due to variations in the flexo sheet plate length, an error occurs between the calculated flexo sheet plate cutting length and the actually required flexo sheet plate length, and this method poses a problem in that plate splicing cannot be performed with high precision. In addition, the flexographic sheet plate is an elastic body, and the cant part expands and contracts during cutting, making it difficult to cut the sheet plate in a straight line.Also, since the plate cylinder or sleeve is cylindrical, the sheet to be attached to it There is a difference between the inner circumference length and outer circumference length of the plate depending on the thickness of the sheet plate, but when canting the sheet plate on a flat table in advance, it is difficult to calculate this difference and cant. This method also has the disadvantage that the plate joining accuracy decreases due to such causes.

Therefore, in the conventional plate splicing method, it is normal for a gap of about 0.5 cranes to occur at the spliced part, and for this reason, when flexographic printing is performed using an endless plate produced by the conventional method, there is a gap between the spliced parts of the printed matter. Color unevenness that was visible to the naked eye occurred in the corresponding areas, making it difficult to perform precise and good endless printing.

In response to this, the Stokesimefx method, which applies laser engraving and photoengraving, has been developed as a precise plate-making method for flexo printing, and these methods enable precise endless plate-making. This method requires a dedicated plate cylinder or sleeve, is expensive in terms of equipment, and is also 2 to 6 times more expensive to produce than the above-mentioned conventional method, resulting in a significant increase in cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for endlessly splicing a flexo sheet plate onto the circumferential surface of a plate cylinder or sleeve easily, inexpensively, and with high splicing accuracy.

In order to achieve the above-mentioned object, the present invention provides a method for endlessly splicing a flexo sheet plate onto a plate cylinder or sleeve. A pair of positioning spacers having approximately the same thickness as the flexo sheet plate are arranged facing each other, and one end of the flexo sheet plate is adhered to the peripheral surface of the plate cylinder or sleeve between these two positioning spacers, and After applying an adhesive tape to one end of the flexo sheet plate to cover the area to be cut in order to prevent the flexo sheet plate from expanding and contracting along the width direction. One end of the flexo sheet plate is cut together with the adhesive tape along a straight line connecting it to a predetermined location, the cut end is removed, and the flexo sheet plate is then wrapped and attached to the circumferential surface of the plate cylinder or sleeve, and the flexo sheet plate is Peel off one end of the flexo sheet plate and adhere the other end of the flexo sheet plate to the peripheral surface of the plate cylinder or sleeve between the two positioning spacers, and then attach the flexo sheet plate to the other end of the flexo sheet plate along the width direction. Apply adhesive tape to cover the area to be cut to prevent expansion and contraction, and then apply adhesive tape to the flexographic sheet along the straight line connecting the same predetermined location on one positioning spacer and the same predetermined location on the other positioning spacer. The flexo sheet plate is cut together and the cut end is removed, and one end of the flexo sheet plate is then reattached for plate splicing.

That is, in the present invention, by cutting the flexo sheet plate on the plate cylinder or sleeve as described above, the length of the flexo sheet plate cut due to variations in the thickness of the flexo sheet plate and the double-sided adhesive tape can be reduced. This prevents the occurrence of errors between the length of the flexo sheet plate and the actually required length, and also ensures that the inner circumference length and outer circumference length of the sheet plate are just the right length when the sheet plate is wrapped around the plate cylinder or sleeve. The sheet plate was cut into sheets, which enabled precise plate joining. In addition, when canting both ends of the sheet plate, adhesive tape is pasted on both ends to prevent the canted portion from expanding and contracting. By using a spacer to precisely cut the sheet plate along the same straight line on the plate cylinder or sleeve, precise plate splicing is ensured.

Next, the present invention will be explained in more detail with reference to the drawings.

In the present invention, first, as shown in FIG. 1, a pair of positioning spacers 2a having approximately the same thickness as the flexo sheet plate are provided at both ends in the axial direction of the circumferential surface of the plate cylinder or sleeve 1;
2b, and both positioning spacers 2a.
, one end 3a of the flexo sheet plate 3 is releasably adhered to the circumferential surface of the plate cylinder or sleeve 1 between 2b, and furthermore, one end 3a of the flexo sheet plate 3 is attached on the surface of the one end 33 of the sheet plate along the width direction to prevent the sheet plate from expanding and contracting. Adhesive tape 4 is pasted to cover the area to be cut.

In this case, there are no restrictions on the shape of the positioning spacer, but a flexible rectangular plate with scales formed thereon can be suitably used. Note that the positioning spacers 2a, 2b and one end of the sheet plate can be attached to the surface of the plate cylinder or sleeve 1 using an adhesive or the like. Also, adhesive tape 4
As the adhesive tape, an adhesive tape made of polyester film or the like can be suitably used.

In the present invention, next, after cutting one end 3a of the sheet plate together with the adhesive tape 4 along a straight line C connecting a predetermined location A of one positioning spacer 2a and a predetermined location B of the other positioning spacer 2b, Remove cut ends.

In this case, the method for cutting the sheet version 3 is to align the side end surface of the cutting tree 5 with the straight line C as shown in FIG. A method in which the sheet plate 3 is cut along the normal direction using a cutter 6 is preferably adopted.

Next, in the present invention, as shown in FIG. 3, the sheet plate 3 is wrapped around the circumferential surface of the plate cylinder or sleeve 1 and attached using an adhesive or the like, and one end 3a of the sheet plate is peeled off and the same process as above is performed. The other end 3b of the flexo sheet plate is removably adhered to the circumferential surface of the plate cylinder or sleeve 1 between the positioning spacers 2a and 2b, and the other end 3b of the sheet plate is
Attach adhesive tape 4 to. Then, the other end 3b of the sheet plate is cut together with the adhesive tape 4 along the straight line C connecting the same point A as above of one positioning spacer 2a and the same point B as above of the other positioning spacer 2b, and the cut end is remove. As a method for cutting the other end 3b of the sheet plate, the above-mentioned method using the cutting tree 5 and the cutter knife 6 as shown in FIG. 3 is preferably employed. after that,
As shown in FIG. 4, one end 3a of the sheet plate is reattached to the peripheral surface of the plate cylinder or sleeve 1 for plate splicing, and both positioning spacers 2a, 2b and adhesive tape 4 are removed. Precise endless plate joining is achieved.

As explained above, according to the endless plate splicing method in flexographic printing according to the present invention, endless plate splicing with extremely high splicing accuracy can be easily and inexpensively performed. Therefore, when flexographic printing is performed using an endless plate manufactured using the method of the present invention, the seams that occur when flexographic printing is performed using an endless plate manufactured using the conventional method may not be visible to the naked eye. Extremely precise and excellent endless printing can be achieved without color unevenness.

[Brief explanation of the drawing]

1 to 3 are schematic diagrams for explaining the procedure for implementing the method of the present invention, in which FIG. 1 is a perspective view, FIGS. 2 and 3 are side views, and FIG. 4 is a diagram illustrating the method of the present invention. FIG. 2 is a side view of an endless plate made using the method. 1... Plate cylinder or sleeve, 2a, 2b... Positioning spacer, 3... Flexo sheet plate, 3a...
・One end of the sheet plate, 3b...Other end of the sheet plate, 4...
·Adhesive tape. Applicant Futatsuka Co., Ltd. (and 1 other person) Agent Takashi Kojima Figure 1 Figure 3 7θ ;b Figure 4 N/C ) 3a □ Mi

Claims (1)

[Claims] 1. In a method of endlessly splicing a flexo sheet plate onto a plate cylinder or sleeve, a pair of positioning spacers having approximately the same thickness as the flexo sheet plate are placed opposite each other at both axial ends of the circumferential surface of the plate cylinder or sleeve. At the same time, one end of the flexo sheet plate is attached to the peripheral surface of the plate cylinder or sleeve between these two positioning spacers, and furthermore, one end of the flexo sheet plate is attached to the one end of the flexo sheet plate to prevent expansion and contraction of the flexo sheet plate along the width direction. After pasting the adhesive tape to cover the area to be cut, cut one end of the flexo sheet plate together with the adhesive tape along the straight line connecting the specified location of one positioning spacer and the specified location of the other positioning spacer. Then, the flexo sheet plate is wrapped around and attached to the circumferential surface of the plate cylinder or sleeve, and one end of the flexo sheet plate is peeled off, and the circumference of the plate cylinder or sleeve between the two positioning spacers is removed. The other end of the flexo sheet plate is affixed to the other end of the flexo sheet plate, and an adhesive tape for preventing expansion and contraction of the flexo sheet plate is affixed along the width direction to the other end of the flexo sheet plate, covering the area to be cut. Cut the flexo sheet plate together with the adhesive tape along a straight line connecting the same predetermined location on one positioning spacer and the same predetermined location on the other positioning spacer, remove the cut end, and then re-attach one end of the flexo sheet plate. An endless plate splicing method in flexo printing, characterized in that the plates are spliced together after each plate is attached.