INTERMEDIATE SLEEVE

Abstract

An intermediate sleeve is provided which is adapted to be mounted on a print cylinder. The intermediate sleeve includes a base layer, a reinforcing layer, a barrier layer, and a surface layer. The sleeve further includes at least one air channel extending longitudinally, circumferentially, or spirally along the interior of the sleeve, at least one air passageway extending from an inner surface of the sleeve into the air channel, and a plurality of orifices extending radially outward from the air channel to an outer surface of the sleeve. The air channel, air passageway, and orifices are in communication such that pressurized air can be supplied from the interior of the print cylinder to the outer surface of the sleeve for mounting a printing sleeve on the intermediate sleeve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view in section of an assembly of one embodiment of the intermediate sleeve of the present invention mounted onto a printing cylinder, with a printing sleeve mounted on the intermediate sleeve; and

FIG. 2 is a cross-sectional view of the intermediate sleeve taken along line 2-2 in FIG. 1 illustrating the channels therein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The intermediate sleeve of the present invention is simple to manufacture and easy to mount and dismount from an underlying print cylinder in flexographic, offset, and gravure printing systems. The design of the sleeve offers several advantages over prior bridge sleeves in that the air channels are provided without requiring the use of special air hoses which must be oriented and embedded in the sleeve. The elimination of such hoses allows the wall thickness of the sleeve to be minimized. In addition, because the air channels are typically formed longitudinally along the length of the sleeve, orifices may be provided at any desired location on the sleeve along the length of the channels. This permits the intermediate sleeve to be compatible with all types of print cylinders and printing sleeves.

The fiber-reinforced polymeric materials used to form the barrier layer in the sleeve construction are also beneficial as they have coefficients of thermal expansion which minimize changes in diameter to the sleeve which could otherwise occur due to processing temperatures encountered during fabrication of the sleeve and during the printing process, and thus provide protection against undesired deformation of the sleeve.

Referring now to FIG. 1, an embodiment of the intermediate sleeve is illustrated in which intermediate sleeve 10 is mounted onto a print cylinder 12. Intermediate sleeve 10 is generally in the shape of a hollow, cylindrically shaped tube having an inner surface 14, and outer surface 16, and first and second ends 18 and 20, respectively.

Print cylinder 12 is mounted for rotation about its longitudinal axis, and in use, would be part of a printing press or other print system (not shown). An air inlet 22 is provided which supplies air under pressure into the interior of the print cylinder from a source (not shown).

As shown in FIG. 1, the inner diameter of sleeve 10 and the outer diameter of cylinder 12 are matched such that there is a close interference fit. The assembly may be linked together by means of a conventional locking mechanism (not shown).

As shown in FIGS. 1 and 2, the intermediate sleeve 10 comprises a base layer 30, a polymeric reinforcement layer 32, a barrier layer 34, and an outer surface layer 36. The base layer 30 preferably comprises a fiber-reinforced polymeric material. The polymeric reinforcement layer 32 preferably comprises a foamed polyurethane.

As shown in FIG. 1, a portion of the upper surface of the polymeric reinforcement layer 32 has been removed so as to form air channels 60 which preferably extend longitudinally along the length of the sleeve. Alternatively, air channels 60 may be formed so that they extend circumferentially or laterally around the sleeve. The portion of the polymeric reinforcement layer is preferably removed by machining.

After the air channels 60 are formed in the polymeric reinforcement layer 32, a barrier layer 34 is preferably applied over the reinforcement layer 32 to form an upper wall for the air channels. Barrier layer 34 may comprise an adhesive tape. Preferably, the barrier layer comprises a fiber-reinforced polymeric material which is wound around the surface of the sleeve by conventional winding techniques.

As shown in FIG. 1, the intermediate sleeve 10 is also provided with one or more orifices or air holes 40 which extend outwardly from the air channels to the outer surface of the sleeve. The orifices 40 are preferably spaced at intervals along the length of the air channels and are in communication with the air channels to allow pressurized air to be released onto the surface of the sleeve.

The intermediate sleeve further includes air passageways 42 which extend from the inner base layer 30 to the air channels 60 in the polymeric reinforcement layer 32 to provide a path for pressurized air supplied from within the print cylinder to the air channels 60 and orifices 40.

Mounting of a printing sleeve (not shown) over the intermediate sleeve 10 may be accomplished by supplying air under pressure to the interior of printing cylinder 12. Printing cylinder 12 is equipped with a plurality of air passageways 66 which provide a path to air passageways 42 and air channels 60 in the intermediate sleeve as shown in FIG. 1. Pressurized air flows through passageways 66, 42, and into air channels 60. From channels 60, the air flows through the plurality of orifices 40 to the outer surface 16 of the sleeve. There, the pressurized air acts to expand the inner diameter of a print sleeve slightly, enough to permit the print sleeve to slide easily along the length of the intermediate sleeve until it is completely mounted. Once the air pressure is removed, the print sleeve contracts to form a tight friction fit with the intermediate sleeve.

As there is often a need for print jobs having varying lengths, the intermediate sleeve 10 is designed to be readily mounted and dismounted from print cylinder 12. As new jobs are processed, intermediate sleeves having different outer diameters, but common inner diameters, may be exchanged by the press operator to provide the correct outer diameter for the desired print job. The intermediate sleeve of the present invention may be manufactured in many sizes and outer diameters to accommodate a variety of different image repeats as is common in the industry.

Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention.

Claims

1. An intermediate sleeve adapted to be mounted on a print cylinder; said sleeve comprising a generally cylindrical tube having an inner surface, an outer surface, and first and second ends; said sleeve including a base layer, a reinforcing layer over said base layer, a barrier layer over said reinforcing layer, and a surface layer; said sleeve further including at least one air channel extending longitudinally, circumferentially or spirally along the interior of said sleeve, and at least one air passageway extending from said inner surface into said air channel such that said at least one air channel is in communication with said at least one air passageway.

2. The intermediate sleeve of claim 1 including a plurality of orifices extending radially outwardly from said at least one air channel to said outer surface of said sleeve.

3. The intermediate sleeve of claim 2 wherein said plurality of orifices are provided at intervals along the length of said at least one air channel.

4. The intermediate sleeve of claim 2 wherein said orifices extend through said barrier layer and said polymeric surface layer.

5. The intermediate sleeve of claim 1 including at least two air channels therein.

6. The intermediate sleeve of claim 1 including at least two air passageways therein.

7. The intermediate sleeve of claim 1 wherein said polymeric reinforcement layer comprises a foamed polyurethane.

8. The intermediate sleeve of claim 1 wherein said polymeric reinforcement layer includes an upper surface and a lower surface, and wherein a portion of said upper surface has been removed to form said at least one air channel.

9. The intermediate sleeve of claim 1 wherein said polymeric reinforcement layer includes at least two air channels formed therein.

10. The intermediate sleeve of claim 1 wherein said barrier layer is selected from an adhesive tape or a fiber-reinforced polymer.

11. The intermediate sleeve of claim 1 wherein said barrier layer comprises an upper wall of said at least one air channel.

12. The intermediate sleeve of claim 1 wherein said polymeric surface layer comprises polyurethane.

13. The intermediate sleeve of claim 1 wherein said at least one air channel has a depth of between about 0.5 to 5 mm.

14. The intermediate sleeve of claim 1 wherein said at least one air channel has a width of from between about 3 to 20 mm.

15. In combination, an intermediate sleeve mounted on a print cylinder, said sleeve having an inner surface, an outer surface, and first and second ends; and comprising a base layer, a reinforcing layer, a barrier layer, and a surface layer; said sleeve further including at least one air channel extending longitudinally, circumferentially, or spirally along the interior of said sleeve, at least one air passageway extending from said inner surface of said sleeve into said air channel; and a plurality of orifices extending radially outwardly from said at least one air channel to said outer surface of said sleeve; said air channel, air passageway and orifices being in communication such that pressurized air can be supplied from the interior of said print cylinder to said outer surface of said sleeve for mounting a printing sleeve thereto.