Low affinity coating blanket for rotary offset presses

Abstract

 The transfer layer (28) of a coating blanket (10) has a low affinity for liquid coating material or ink, rather than a high affinity which characterizes conventional nitrile rubber and photopolymer blankets. The low affinity material, for example a fluorinated polymer or a silicone elastomer, resists wetting by the liquid media, and has a tendency to form a non-spreading bead or droplet of the liquid coating material on the transfer media surface. The low affinity surface provides smooth and quick release of the substrate from the nip between the coating blanket cylinder (12) and the impression cylinder (20). The low affinity transfer surface further inhibits the accumulation of ink and/or liquid coating material, thereby preventing split images, ghost images, offset images and back-trapping defects.

Description

[0001] This invention relates generally to sheet-fed or web-fed, rotary offset or flexographic printing presses, and more particularly to an improved coating blanket for the application of protective and/or decorative coatings to the printed surface of freshly printed sheets or web stock.

[0002] In rotary offset printing, an image which is to be reproduced on a sheet of paper or some other print stock is formed on a printing plate which is attached to the surface of a rotatable plate cylinder. The image is not printed directly from the plate onto the paper, but is first transferred to an intermediate ink transfer blanket, which is mounted on a rotatable blanket cylinder. The blanket transfers (offsets) the inked image to a sheet of paper which is fed through the nip between a rotatable impression cylinder and the blanket cylinder. The offset printing press thus includes a plate cylinder which carries the printing image, a blanket cylinder which has an ink transfer surface for receiving the inked image, and an impression cylinder which presses the paper against the blanket so that the inked image is transferred to the paper.

[0003] In some printing applications, it is desirable that the press be capable of applying a protective and/or decorative coating over all or a portion of the surface of the printed sheets. Conventional coating liquids include varnish, lacquer, dye and adhesives. Some coatings are formed of a UV-curable or water-soluble resin applied as a liquid solution or emulsion via an applicator roller and coating blanket over the freshly printed sheets to protect the ink from set-off or offset and improve the appearance of the sheets. The use of such coatings is particularly desirable when glossy, decorative or protective finishes are required such as in the production of posters, record jackets, brochures, magazines, folding cartons, labels and the like.

[0004] In press jobs where a liquid coating is to be applied, the coating operation is performed after the final ink printing has been completed, preferably by an in-line coater. Conventional coating apparatus which is operable as an in-line press operation utilizes an engraved applicator roller, with the liquid coating being supplied to the engraved roller by means of a doctor blade assembly. Liquid coating material picked up by the engraved applicator roller is transferred to a coating blanket cylinder for subsequent application to a printed sheet.

[0005] Conventional blankets have a pliable surface made of a material such as nitrile rubber which is receptive to and wettable by ink and/or liquid coating material. Such blanket materials are said to have a high affinity for the liquid coating media. Those high affinity materials have exhibited some retention and/or absorption, and did not provide a clean release of the liquid transfer media to a receptor media (paper sheet) without retaining an unacceptable ink trace on the blanket surface, known in the trade as "back-trapping".

[0006] Conventional coating blankets having a base layer of durable, flexible material, for example, woven fabrics or reinforced paper, and may include one or more intermediate compressible layers, typically of soft rubber, and an outer transfer layer, typically of vulcanized nitrile rubber, which has a high affinity for liquid coating materials and/or ink. The outer transfer layer is secured by adhesive bonding to the intermediate compressible layer. The nitrile rubber layer is hardened by vulcanizing and its transfer surface is finished by calendaring, grinding or milling the hardened rubber in successively thin layers until a desired thickness is obtained.

[0007] Photopolymer materials are used in the construction of conventional coating blankets and are available from E.I. DuPont de Nemours & Company of Wilmington, Delaware under its registered trademark CYREL. The CYREL photopolymer blankets have a photosensitive elastomeric layer of solvent-soluble, thermoplastic elastomeric composition which, upon exposure to actinic light, forms a solvent-insoluble, elastomeric relief body. In the production of such blankets, a transfer body having a uniform coating surface is produced by exposing the photosensitive layer through an image-bearing transparency. The photosensitive layer typically includes an addition-polymerizable, ethylenically unsaturated compound or mixture of compounds, a solvent-soluble elastomeric binder, and a dispersion of an addition-polymerization initiator activatable by actinic light.

[0008] Removal of the layer in nonexposed areas, for example by treatment with a suitable solvent, leaves a coating relief surface. Such flexographic coating blankets are not as elastomeric as the molded rubber blankets. Moreover, the photosensitive elements tend to cold flow due to high monomer concentrations, and do not have the desired features of vulcanized rubber without reducing solvent solubility as well. Such photopolymer coating blankets also generally possess tacky surfaces which lead to picking and tearing of paper during coating. The printed image elements are blurred by picked-up paper fibers. The photopolymer materials may be treated, for example with bromine, iodine or chlorine solutions, to reduce tackiness, but the photopolymer blanket surface will become tacky again during long coating runs. The after-treatment of photopolymer surfaces to reduce tackiness destroys the smooth, uniform surface on the coating blanket which further interferes with smooth coating performance. Finally, such photopolymer blankets are not flexible enough to be used in combination with packing sheets for accommodating spot coating. The blanket must be custom made for each particular spot coating application.

[0009] A problem experienced by press operators in connection with such conventional coating blankets is the accumulation of ink traces on the blanket surface, so that splitting of the image occurs. A partial or ghost image may appear on the next advancing sheet, producing what is known in the trade as offset image, sometimes referred to as "back-trapping". Accumulation of ink or hardened coating material on the coating blanket transfer surface will inhibit the pick-up of liquid coating material from the applicator roller. Consequently, the finish will be dull, and the colors muddy.

[0010] Another problem which has been observed, particularly at high press speeds, is the sticking or slow release of the sheets from the coating blanket cylinder. Sticking or slow release may cause a sheet of paper to adhere to the blanket, requiring shut down of the press so that the sheet can be cleared. If such sticking/slow release should cause multiple sheets to jam the nip, the coating blanket may be damaged beyond repair and must be replaced.

[0011] When back-trapping occurs, the press must be stopped so that the coating blanket transfer surface may be washed clean. Some coating blankets may be cleaned only by special cleaning chemicals which may be toxic, acidic or caustic, and may cause personal injury to press personnel. Moreover, such chemical solutions may attack the blanket and eat away its transfer surface.

[0012] According to the present invention, a coating blanket is provided in which the transfer surface of the blanket has a relatively low affinity for the liquid coating material or ink, rather than a high affinity material such as vulcanized rubber of the kind used in conventional blanket construction. This is accomplished by a coating blanket assembly having a dimensionally stable carrier sheet which supports a transfer layer of a non-tacky, low affinity material, for example a fluorinated polymer resin such as polytetrafluoro-ethylene or a silicone elastomer resin, such as trichloromethyl-silane copolymerized with difunctional silane.

[0013] Such materials have a low affinity for the liquid transfer media, such as liquid coating material or liquid printing ink, so that the coating material or ink will not adhere to the coating blanket surface, and will instead be released and transferred to the printed sheets. The coating blanket material is considered to have a low affinity for a given liquid media if it will cleanly release the liquid media to a receptor media substantially without retaining residue. That is, the low affinity transfer material is characterized by its ability to resist wetting by the liquid coating media, and has a tendency to form a non-spreading bead or droplet of the liquid coating media on the transfer media surface. The adhesive interface attraction of coating to the blanket is less than the adhesive interface attraction of the coating to the paper. Thus, most of the coating material is transferred to the paper, and only a trace amount of coating remains on the blanket transfer surface.

[0014] Operational features and advantages of the present invention will be understood by those skilled in the art upon reading the detailed description which follows with reference to the attached drawings, wherein:

FIGURE 1 is a simplified, schematic diagram showing the relative positions of the principal components of a rotary offset printing press, with the coating blanket of the present invention being used for applying a protective coating to a freshly printed sheet;

FIGURE 2 is a fragmentary, greatly enlarged, sectional view of a coating blanket having a dimensionally stable carrier sheet on which a transfer layer of non-tacky, low affinity material is bonded;

FIGURE 3 is a perspective view, partially in section and partially broken away, showing the installation of the coating blanket of Figure 2 on a coating blanket cylinder;

FIGURE 4 is a perspective view, partially in section, of a compressible blanket embodiment of the present invention;

FIGURE 5 is a sectional view, partially broken away, of the compressible blanket of FIGURE 4 installed on a coating blanket cylinder;

FIGURE 6 is a schematic side elevational view in which the coating blanket of the present invention is being used for offset coating material transfer in a four color offset rotary printing press;

FIGURE 7 is an enlarged fragmentary side elevational view taken substantially within the circular area designated "7" of FIGURE 6 and showing the coating blanket of the present invention as used in an in-line coating operation;

FIGURE 8 is a perspective view, partially in section, of a laminated coating blanket embodiment of the present invention; and,

FIGURE 9 is a fragmentary, greatly enlarged, sectional view of a coating blanket having a dimensionally stable carrier sheet on which a composite transfer layer is adhesively bonded.

[0015] In the description which follows, like parts are indicated throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details of the present invention.

[0016] The improved coating blanket 10 of the present invention will now be described as used generally in a rotary offset printing press. Referring now to FIGURE 1, FIGURE 2 and FIGURE 3, the coating blanket 10 is mounted on a coating blanket cylinder 12 in a rotary offset printing press 14. The offset printing press 14 includes a plate cylinder 16, an ink transfer blanket cylinder 18, and an impression cylinder 20. Mounted on the plate cylinder 16 is a metal plate 22 (either zinc or aluminum) which has been given a sensitized coating on which an image has been formed by a photographic process. A cluster 24 of moistening or dampening rollers applies a thin film of dampening liquid to the printing plate 22, which then comes into contact with a cluster 26 of inking rollers. The ink is rejected by the hydrophillic non-image holding areas of the printing plate 22, but is absorbed by the ink receptive (oleophillic) surface areas of the image.

[0017] Referring to Figure 2, the coating blanket 10 has a low affinity transfer layer 28 which receives the liquid coating material from an applicator roller 30 and transfer the coating to a freshly printed sheet S of paper. The printed sheet S is fed through the nip N between the impression cylinder 20 and the coating blanket cylinder 12. As the impression cylinder 20 presses the sheet against the coating blanket 10, liquid coating material is transferred to the sheet.

[0018] That is, the sheet S is fed between the coating blanket cylinder 12 and the impression cylinder 20 and receives the liquid coating material directly from the coating blanket 10 to provide a decorative and/or protective coating on the freshly printed sheet. The pressure applied by the applicator roller 30 to the coating blanket cylinder 12 is adjustable to obtain a uniform transfer of liquid coating material, without crushing or otherwise deforming the coating blanket 10.

[0019] Referring again to FIGURE 2, the blanket assembly 10 includes a base carrier layer 32 made of a durable, dimensionally stable and flexible material, for example a sheet of MYLAR polyester film. Flexible materials other than MYLAR polyester film may be used to good advantage for forming the base carrier sheet 32. For example, metallic sheet materials such as stainless steel, aluminum and copper may also be used. The carrier sheet gauge thickness should be sufficient to provide strength and dimensional stability and yet be flexible enough to easily wrap about the coating blanket cylinder 12. Generally, gauge thicknesses in the range of about 2 mils to about 8 mils, preferably about 4 mils, are satisfactory.

[0020] Referring to Figure 3, the coating blanket 10 has a trailing end portion 10A which is terminated by a clamp plate 34. The leading end 10B of the coating blanket assembly 10 is secured within an elongated slot of a ratchet wheel 36. One or more packing sheets 38 are sandwiched between the base carrier sheet 32 and the external surface of the coating blanket cylinder 12 as shown in Figure 3. The packing sheets 38 raise the coating blanket surface over a localized relief area corresponding to the surface of the printed sheet which is to be coated. The packing sheets 38 and the coating blanket 10 are assembled onto the blanket cylinder 12 by first attaching the clamp plate 34 onto the coating blanket cylinder 12 within a channel pocket 40. The clamp plate 34 is secured by threaded fastener bolts 42, and the ratchet wheel 36 is secured by a ratchet clamp (not shown). After the coating blanket 10 has been secured in place, with the packing sheets 38 confined between the coating blanket 10 and the coating blanket cylinder 12, the ratchet wheel 36 is tightened to secure the coating blanket 10 in tension about the coating blanket cylinder 12.

[0021] Referring now to FIGURE 4, a compressible blanket assembly 100 is illustrated. To avoid crushing, denting or otherwise deforming the hard, low affinity transfer layer 28, the transfer layer 28 is supported by a resilient intermediate layer 44 of soft, compressible rubber. The base carrier sheet 32 and the intermediate compressible layer 44 are stabilized and secured together by an adhesive deposit 46. The low affinity transfer layer 28 is preferably formed and secured to the compressible layer 44 by adhesively bonding a sheet of a low affinity material such as a fluorinated polymer resin, for example TEFLON PTFE or FEP film, or a silicone elastomer. The transfer layer 28 may also be formed and secured by spray coating, bulk forming and hot melt extrusion.

[0022] Referring to FIGURE 5, the compressible blanket assembly 100 is secured about the coating cylinder 12 as previously described in connection with the coating blanket 10.

[0023] Referring now to FIGURE 6 and FIGURE 7, the coating blanket 10 of the present invention will now be described as used for applying a protective and/or decorative coating to the freshly printed surface of sheets printed in a sheet-fed or web-fed, offset rotary or flexographic printing press, herein generally designated 50. In this instance, as shown in FIGURE 6, the coating blanket 10 of the present invention is mounted on a delivery/transfer cylinder 12 in a four color printing press, such as that manufactured by Heidelberg Druckmaschinen AG of Germany under its designation Heidelberg Speedmaster 102V. The press 50 includes a press frame 54 coupled at one end, herein the right end, with a sheet feeder 56 from which sheets, herein designated S, are individually and sequentially fed into the press, and at the opposite end, with a sheet delivery stacker 58 in which the finally printed sheets are collected and stacked. Interposed between the sheet feeder and the sheet delivery stacker are four substantially identical sheet printing units 60, 62, 64 and 66 which can print different color inks onto the sheets as they are moved through the press 50.

[0024] As illustrated, the printing units are substantially identical and of conventional design, herein including a sheet-fed cylinder 68, a plate cylinder 16, an ink blanket cylinder 18 and an impression cylinder 20, with each of the first three printing units having a transfer cylinder 70 disposed to withdraw the freshly printed sheets from the adjacent impression cylinder 20 and transfer the freshly printed sheets to the next printing unit via an interstation transfer cylinder 72. The final printing unit 66 herein is shown as equipped with a delivery/transfer coating cylinder 12 mounted on a delivery drive shaft 74. The deliver/transfer coating cylinder 12 also supports the printed sheet S as it is moved from the final impression cylinder by a delivery conveyor system, generally designated 76, to the sheet delivery stacker 58.

[0025] The delivery conveyor system 76 as shown in FIGURE 6 is of conventional design and includes a pair of endless delivery gripper chains 78, only one of which is shown carrying laterally disposed gripper bars having gripper elements G used to grip the leading edge E of a sheet S after it leaves the nip N between the delivery coating cylinder 12 and impression cylinder 20 of the final printing unit 66. As the leading edge E of the sheet S is gripped by the grippers, the delivery chains pull the sheet S away from the coating blanket cylinder 12 and convey the freshly printed and coated sheets to the sheet delivery stacker 58.

[0026] An in-line doctor blade coating apparatus 80 is provided for applying a protective or decorative coating or ink to the printed sheets S. This in-line coating arrangement enables the press to be operated in the normal manner without the loss of the final printing unit, and without requiring any press modifications, by employing the existing press delivery drive shaft 74 as the mounting location for a delivery transfer cylinder 12 on which the liquid material coating blanket 10 of the present invention is mounted. In presses having delivery systems such as skeleton wheels mounted on the delivery drive shaft, conversion to a coating operation may be quickly and easily accomplished by mounting on the press delivery drive shaft 74 in place of the skeleton wheels, a coating blanket equipped delivery cylinder 12 capable of performing a blanket coating function as well as the delivery transfer function. By utilizing a coating blanket 10 on the delivery/transfer cylinder 12 to also act as a coating blanket cylinder, protective coating may be applied to the printed sheets S in precise timed registration, and will permit the press to be operated with its full complement of printing units.

[0027] The coating apparatus 80 includes a relatively simple, positive acting and economical doctor blade coating unit 82, mounted to the press frame 54 downstream of the delivery drive shaft 74 and positioned to apply liquid coating material to the coating blanket 10 mounted on the delivery coating cylinder 12 which is secured to the delivery drive shaft. As shown in FIGURE 7, the doctor blade coating unit 82 includes a pair of side frames 84, only one of which is shown, it being understood that the other side frame is substantially the same as that of the side frame illustrated, attached to the opposite side of the press frame. Pivotally mounted to one end of each of the side frames is a support bracket 86 carrying one end of a doctor blade reservoir 88 and a cooperating liquid material applicator roller 30, each disposed to extend laterally across the press parallel with the delivery/transfer coating cylinder 12. The coating unit 82 is mounted between the upper and lower support rails of the delivery chains downstream of the delivery coating cylinder 12, and positioned so that the outer peripheral surface of the applicator roller 30 can be engaged against the coating blanket 10 on the delivery coating cylinder 12 mounted on the delivery drive shaft 74.

[0028] As shown in FIGURE 7, the support bracket 86 is pivotally attached to the end of the side frame 54 by a stub shaft 90 disposed at the lower end portion of the bracket, and can be pivoted about the shaft by an extensible cylinder 92, herein shown as a pneumatic cylinder, one end of which is secured to the side frame, and the opposite end of which is coupled through a pivot shaft 94 to the upper end portion of the bracket 86. By extending or retracting the applicator roller 30, the engagement pressure of the applicator roller 30 against the coating blanket surface may be controlled, and the applicator roller 30 may be completely disengaged from the transfer coating blanket 10 in a non-operative, idle position.

[0029] The coating applicator roller 30, which is of conventional design and preferably having an engraved ceramic or chrome transfer surface, is designed to pick up a predetermined volume of liquid coating material or ink from the doctor reservoir, and then uniformly transfer the liquid coating material to the coating blanket 10 on the delivery/transfer coating blanket cylinder 12. To effect rotation of the applicator roller, a drive motor 96, either hydraulic or electric, is attached to one of the side frames and coupled to a source of power (not shown) through charge and return fittings.

[0030] In the practice of either blanket embodiment of the invention, a preferred fluorinated polymer material for making the transfer layer 28 is polytetrafluoroethylene (PTFE) fluorocarbon polymer resin, or fluorinated ethylene propylene (FEP) resin, both sold by DuPont under its trademark TEFLON. Those materials are curable to a hard, smooth transfer surface, resist abrasion and deformation, and are characterized by a low surface coefficient of friction and a low affinity for liquid coating materials and/or ink. They are also non-reactive to press room chemicals.

[0031] Fluorinated, curable polymers which are useful in this invention contain at least about 37 percent by weight of carbon-bonded fluorine and preferably wherein at least about 50 percent of the non-skeletal carbon valence bonds are fluorine. Exemplary of such polymers are fluorosilicone polymers which are generally known as perfluoro alkyl alkylene siloxanes. Those polymers contain a terminal perfluoro alkyl group which is positioned no closer than two carbon atoms from the silicone atom, and additionally contain a minor amount of substituent groups which will allow curing or crosslinking to occur. These substituent groups may be, for example, silicone-bonded hydrogen atoms, vinyl groups or peroxy-activatable groups. A preferred curable fluorosilicone polymer, trifluoropropylmethyl vinyl polysiloxane, is commercially available from the Dow Corning Company under the trade name LS-53.

[0032] The low affinity blanket transfer layer 28 should generally have a thickness in the range of from about 1 mil to about 5 mils, and preferably about 2 mils. The hardness of the transfer layer should be sufficient to provide uniform nip contact area during the coating transfer operation and maintain physical integrity. Generally, fluorinated elastomers having a Shore A durometer hardness of 20-80, preferably about 50, are satisfactory.

[0033] The low affinity layer 28 may be conveniently formed by curing the fluorinated polymers in situ at the time of manufacture of the blanket. Curing or crosslinking agents for curing fluorinated polymers are generally well known in the art. Curing conditions vary depending upon the curable fluorinated polymer and curing agent utilized, with effective cures being obtained at temperatures up to about 450°F (232.2°C) for a period of from about one minute to about fifteen hours, and more usually from about five minutes to about thirty minutes.

[0034] Exemplary silicone elastomers include the cured or further polymerized product of a silicone gum, such as dimethyl vinyl polysiloxane. Preferably, the gum is mixed with a silicone resin with equal parts by weight of the gum and resin. However, other proportions of these ingredients are also useful.

[0035] The low affinity transfer layer 28 should have sufficient thickness to permit adequate wear life in terms of abrasion resistance. The hardness of the blanket transfer layer should allow sufficient elongation without tensile failure. A silicone elastomer having about 30 to about 70 Shore A durometer and preferably about 50 Shore A durometer is satisfactory.

[0036] In the manufacture of the blanket assemblies 10 or 100 of this invention, the base carrier sheet 32 and the compressible intermediate layer 44 should be primed with a suitable primer for fluorinated elastomers to assure a compatible bond surface and to ensure reliable repeatability of bond strength. Catalyzed fluorinated polymer may then be applied to the primed surface by conventional means such as calendaring, bulk loading, or by spraying to form a low affinity layer 28 having the desired uniform thickness. The blanket assembly may then be inserted into a mold and cured at from about 200°F (93.3°C) to about 400°F (204.4°C) under a pressure of about 350 psi (246,085 kgs/sq.m).

[0037] Referring now to FIGURE 8, a laminated blanket assembly 150 is illustrated. In this embodiment, the base carrier layer 32 is a sheet of MYLAR polyester film having a gauge thickness of about 4 mils. The coating transfer layer is a sheet of TEFLON fluorinated ethylene propylene copolymer (FEP) film having a gauge thickness of 2 mils. The TEFLON FEP film layer 28 is laminated onto the MYLAR carrier sheet 32 by an adhesive deposit 46. The laminated blanket assembly 150 is characterized by impact and scratch resistance, and high flexibility for providing sharp relief edges and high definition when used in combination with packing sheets for spot coating applications.

[0038] Referring now to FIGURE 9, a printing blanket 200 has an ink transfer layer 98 which is a composite mixture of a high affinity component and a low affinity component. The high affinity component is nitrile rubber, which is receptive to and has a relatively high affinity for printing ink, and the low affinity component is a fluorinated polymer resin such as polytetrafluoroethylene (PTFE), or fluorinated ethylene propylene (FEP) resin, or a silicone elastomer resin. The high affinity component provides good ink pick-up, and the low affinity component provides good release. Consequently, the composite layer 98 is a compromise between a conventional nitrile rubber blanket and the low affinity coating blanket embodiments 10, 100 and 150 described above. The transfer layer 98 of the ink blanket assembly 200 will accept some ink, yet will readily release the printed sheet quickly and smoothly. The printing blanket 200 is primarily intended for ink transfer applications, and is illustrated attached to the ink blanket cylinder 18 in FIGURE 1.

[0039] The composite transfer layer 98 may be manufactured as a hot melt film extrusion in which pellets of nitrile rubber are mixed with pellets of a low affinity material, for example TEFLON PTFE or TEFLON FEP in various proportions. A dry blend of nitrile rubber pellets and elastomer pellets are separately metered into a twin-screw extruder equipped with a filter and sheeting dye. Various proportions of the nitrile rubber to the low affinity material may be employed, with the nitrile rubber component being dominant for ink transfer applications.

[0040] It will be apparent that the low affinity coating blanket of the present invention provides significant advantages with respect to conventional coating blankets. The low affinity coating blanket embodiment is less expensive to manufacture as compared to conventional, vulcanized nitrile rubber coating blankets. The embodiments which utilize a fluorinated polymer or a silicone elastomer are more durable and resist scratching/deformation more effectively than conventional vulcanized rubber blankets. Because of the low affinity and non-tacky surface of such materials, the printed sheets are released smoothly, quickly and easily from the nip between the coating blanket cylinder and the impression cylinder, even at high speed operation. Coating blankets made of such low affinity materials are sufficiently flexible to be used in combination with packing sheets of different sizes to provide for uniform coating over designated localized areas of the printed sheets. The low affinity blanket is also resistant to chemical attack, and may be washed and cleaned with any available press room chemical solutions. Since the low affinity blanket surface refuses the accumulation of ink and/or coating material, split images, ghost images, offset images and back-trapping defects are eliminated. Because liquid coating material will not permanently adhere to the low affinity blanket surface, hardened coating residue may be easily peeled away or stripped clean from the coating blanket transfer surface with a soft cloth, without scraping or applying a reactive chemical solution.

Claims

1. A blanket assembly (10) for attachment to a cylinder (12) in a printing press (14) characterized as follows:
   a base carrier sheet (32); and,
   a liquid media transfer layer (28) supported by the base carrier sheet, the transfer layer being made of a material having a low affinity for the liquid media.

2. A blanket assembly (10) as defined in claim 1, said transfer layer (28) comprising a fluorinated polymer resin.

3. A blanket assembly (10) as defined in claim 2, wherein the fluorinated polymer resin comprises tetrafluoroethylene fluorocarbon polymer resin.

4. A blanket assembly (10) as defined in claim 2, wherein the fluorinated polymer resin comprises fluorinated ethylene-propylene resin.

5. A blanket assembly (10) as defined in claim 2, wherein the fluorinated polymer resin comprises a curable, fluorosilicone polymer.

6. A blanket assembly (10) as defined in claim 5, wherein the fluorosilicone polymer comprises perfluoro alkyl alkylene siloxane.

7. A blanket assembly (10) as defined in claim 5, wherein the curable fluorosilicone polymer comprise trifluoropropyl- methyl vinyl polysiloxane.

8. A blanket assembly (10) as defined in claim 1, wherein the transfer layer (28) comprises silicone elastomer resin.

9. A blanket assembly (10) as defined in claim 8, wherein the silicone elastomer resin comprises trichloromethylsilane copolymerized with difunctional silane.

10. A blanket assembly (10) as defined in claim 1, wherein the base carrier sheet (32) comprises polyester film.

11. A blanket assembly (10) as defined in claim 1, the transfer layer (28) comprising a spray coating of low affinity material bonded to the base carrier sheet (32).

12. A blanket assembly (10) as defined in claim 1, the transfer layer (28) comprising a film of low affinity material bonded to the base carrier sheet.

13. A blanket assembly (10) as defined in claim 1, including a resilient, compressible layer (44) disposed intermediate the base carrier sheet (32) and the liquid media transfer layer (28), the transfer layer comprising a coating of low affinity material bonded to the compressible layer (44).

14. A blanket assembly (10) as defined in claim 1,
   the transfer layer (28) including a composite mixture (98) of a material having a low affinity for the liquid media and a material having a higher affinity for the liquid media.

15. A blanket assembly (10) as defined in claim 14, wherein the low affinity material comprises a fluorinated polymer resin and the high affinity material comprises nitrile rubber.

16. In a printing press (50) having a delivery/transfer cylinder mounted on a delivery drive shaft (74) adjacent to an impression cylinder (20), coating apparatus (80) including an applicator roller (30) for transferring liquid coating material movably mounted on the press for movement to extended and retracted positions relative to the delivery/transfer cylinder, the improvement comprising a coating blanket (10) mounted on said delivery/transfer cylinder for engagement with the applicator roller in the extended position, said coating blanket having a transfer layer (28) made of a non-tacky material which resists adhesion by the liquid coating material.

Drawing