Flexo Sleeves Gain Traction
Polymer flexographic printing sleeves eliminate problems associated with conventional plate mounting.
June 2008 by Jean-Marie Hershey
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Digital imaging of flexographic plates has brought about many improvements when compared to conventional platemaking methods. Sleeve technology offers further refinements to the process. Advances in flexo sleeve technology are yielding opportunities in markets traditionally dominated by offset and gravure—markets such as folding cartons and shrink sleeves.
Lightweight, durable, easy-to-handle flexo sleeves not only work well with less expensive substrates such as tissue, napkins, and paper towels, but also provide excellent laydown of solid and metallic inks in packaging applications. Flexo sleeves are being used in two ways: as carrier rolls for flat, imaged plates mounted on the surface or with the image directly engraved (in-the-round) on the sleeve surface. Each provides productivity enhancements for package printers.
With sleeves that serve solely as carrier rolls, imaged printing plates can be mounted to the sleeves offline, which can then be installed onto cylinders in the print stations using compressed air to expand the sleeves, allowing them to slide into position on the cylinders. The use of sleeves in this way provides increased production flexibility by using the premounted plates to provide quick changeovers for short runs and design changes. It is especially effective for short-run, repeat jobs, since the sleeves can be taken off the press and carefully stored with the plates mounted on the sleeves.
In-the-round (ITR) technology refers to digitally imaged, continuous polymer printing sleeves that permit flexographers to print images on a wide range of substrates by imaging and processing the printing form directly on the sleeve. The photopolymer sleeve may be a continuous pre-manufactured sleeve with a seamless layer of photopolymer topped by a laser ablation mask (LAM) coating, ready for imaging, exposure, and processing. It can also involve mounting individual pieces of photopolymer on a base sleeve with stickyback tape, then imaging, exposing, and processing them in the same manner as the photopolymer sleeve with the LAM coating.
Because photopolymer sleeves imaged in-the-round do not use plates to carry the image, a host of problems associated with conventional flexo plate mounting is eliminated. These problems include plate lift and bounce, misregistration, distortion, and waste.
“Flexographers used to image on a flat photopolymer plate and attach the plate to a round cylinder with stickyback tape,” says Mike Smoot, business manager for Xymid Print Sleeves, Xymid, LLC. “The thicker the plate and the smaller the diameter of the cylinder, the greater the potential for misregistration and distortion. In contrast, the alignment of sleeves is spot-on.”
Lightweight, durable, easy-to-handle flexo sleeves not only work well with less expensive substrates such as tissue, napkins, and paper towels, but also provide excellent laydown of solid and metallic inks in packaging applications. Flexo sleeves are being used in two ways: as carrier rolls for flat, imaged plates mounted on the surface or with the image directly engraved (in-the-round) on the sleeve surface. Each provides productivity enhancements for package printers.
With sleeves that serve solely as carrier rolls, imaged printing plates can be mounted to the sleeves offline, which can then be installed onto cylinders in the print stations using compressed air to expand the sleeves, allowing them to slide into position on the cylinders. The use of sleeves in this way provides increased production flexibility by using the premounted plates to provide quick changeovers for short runs and design changes. It is especially effective for short-run, repeat jobs, since the sleeves can be taken off the press and carefully stored with the plates mounted on the sleeves.
In-the-round (ITR) technology refers to digitally imaged, continuous polymer printing sleeves that permit flexographers to print images on a wide range of substrates by imaging and processing the printing form directly on the sleeve. The photopolymer sleeve may be a continuous pre-manufactured sleeve with a seamless layer of photopolymer topped by a laser ablation mask (LAM) coating, ready for imaging, exposure, and processing. It can also involve mounting individual pieces of photopolymer on a base sleeve with stickyback tape, then imaging, exposing, and processing them in the same manner as the photopolymer sleeve with the LAM coating.
Because photopolymer sleeves imaged in-the-round do not use plates to carry the image, a host of problems associated with conventional flexo plate mounting is eliminated. These problems include plate lift and bounce, misregistration, distortion, and waste.
“Flexographers used to image on a flat photopolymer plate and attach the plate to a round cylinder with stickyback tape,” says Mike Smoot, business manager for Xymid Print Sleeves, Xymid, LLC. “The thicker the plate and the smaller the diameter of the cylinder, the greater the potential for misregistration and distortion. In contrast, the alignment of sleeves is spot-on.”
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