Printing sleeve and method of manufacturing the same
The present invention is directed to the manufacture of “seamless” photosensitive printing elements from substantially planar printing plate blanks wrapped around cylindrical printing sleeves or carriers. The method comprises the steps of cutting a photosensitive printing element to a size for wrapping around a printing sleeve, trimming ends of the photosensitive printing element to create a gap when the printing element is wrapped around the printing sleeve, attaching the photosensitive printing element to the printing sleeve and filling the gap between the ends of the photosensitive printing element with a filler material.
1 . A method of manufacturing a flexographic printing element comprising the steps of:
a) cutting a photosensitive printing element to a size for wrapping around a printing sleeve;
b) trimming ends of the photosensitive printing element to create a gap when the printing element is wrapped around the printing sleeve;
c) attaching the photosensitive printing element to the printing sleeve; and
d) filling the gap between the ends of the photosensitive printing element with a filler material,
wherein a seamless photosensitive printing element is formed on the printing sleeve.
2 . The method according to claim 1 , wherein the step of trimming the photosensitive printing element comprises beveling the ends of the photosensitive printing element.
3 . The method according to claim 2 , wherein the ends of the photosensitive printing element are beveled up to a depth of about 0.030 inches.
4 . The method according to claim 1 , wherein the filler material comprises a photosensitive composition that is the same composition used in the photosensitive printing element.
5 . The method according to claim 1 , wherein the filler material is liquid or molten when it is injected into the gap, and thereafter solidifies.
6 . The method according to claim 1 , further comprising the step of removing excess filler material to provide a desired thickness of the photosensitive printing element.
7 . The method according to claim 6 , wherein the step of removing excess filler material comprises squeegeeing off excess material or grinding the photosensitive printing element to a desired thickness.
8 . The method according to claim 6 , wherein the filler material is injected into the gap using a spool valve.
9 . The method according to claim 1 , comprising the step of back-exposing the photosensitive printing element to actinic radiation prior to step a).
10 . The method according to claim 1 , wherein the step of attaching the photosensitive printing element to the printing sleeve comprises laminating the photosensitive printing element to the printing sleeve.
11 . The method according to claim 1 , wherein the printing sleeve comprises a cylindrical sleeve layer having a backing layer mounted thereon, and wherein when the printing element is attached to the printing sleeve, the printing element contacts with the backing layer.
12 . The method according to claim 11 , wherein the backing layer is selected from the group consisting of double-sided self-adhesive tape, foam cushioning, and transfer tape.
13 . The method according to claim 12 , wherein the backing layer is double-sided self-adhesive tape.
14 . The method according to claim 11 , wherein the cylindrical sleeve layer is selected from the group consisting of metal, plastics, glass-fiber reinforced plastic, and the like.
15 . The method according to claim 14 , wherein the cylindrical sleeve layer is nickel.
16 . The method according to claim 1 , wherein the photosensitive printing element is coated with an actinic radiation opaque layer.
17 . The method according to claim 16 , wherein the actinic radiation opaque layer comprises carbon black.
18 . The method according to claim 1 , comprising the steps of imaging and exposing the photosensitive printing element after the photosensitive printing element is mounted on the printing sleeve.
19 . The method according to claim 18 , further comprising the step of developing the imaged and exposed photosensitive printing element to remove uncured photopolymer.
20 . The method according to claim 19 , wherein the step of developing the photosensitive printing element is accomplished using thermal development.
21 . The method according to claim 1 , wherein the thickness of the photosensitive printing element is about 0.030 inches to about 0.287 inches.
22 . The method according to claim 2 , wherein the edges of the photosensitive printing element are beveled using an automatic cutting table.
23 . The method according to claim 1 , wherein the printing sleeve is mounted on a printing cylinder.
24 . An apparatus for manufacturing a relief image printing element comprising:
a) means for supporting a cylindrical printing sleeve;
b) means for cutting a photosensitive printing element to a size that is wrappable around the cylindrical printing sleeve;
c) means for trimming ends of the photosensitive printing element to create a gap when the photosensitive printing element is wrapped around the printing sleeve; and
d) means for filling the gap between the ends of the photosensitive printing element with a filler material;
wherein a seamless photosensitive printing element is formable on the printing sleeve.
25 . The apparatus according to claim 24 , wherein the means for filling the gap comprises a spool valve that is capable of injecting molten filler material into the gap between the ends of the photosensitive printing element.