JPH1128802A - Lithography printing system having reusable supporting face and lithographic structure being used together - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lithographic print structure removable from a permanent support. SOLUTION: A lithographic print structure 100 is secured removably to a permanent support, e.g. a metal sheet 110 secured (normally, through a clamp) to a plate cylinder 106, through an adhesive or a negative pressure. Alternatively, the support may be the surface of the plate cylinder. A traditional 'plate' is replaced by a thin print member which can be produced easily. The used print member is separated from the support.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to digital printing apparatus and methods, and more particularly to a lithographic printing plate structure that can be imaged on or off a printing press using a digitally controlled laser output. It is about.

[0002]

2. Description of the Related Art In offset lithographic printing,
The image is present on the plate or mat as a pattern of ink receptive (oleophilic) and ink repellent (oleophobic) surface areas. Ink is retained on the lipophilic area and the plate is rejected where the oleophobic is present. In a dry printing system, the plate is simply inked and the image is transferred onto the recording material. That is, the plate first contacts an intermediate compliant surface called a blanket cylinder, which then
The image is applied to paper or other recording media. In a typical paper-fed printing system, the recording medium is pinned to an impression cylinder or image cylinder which makes contact with a blanket cylinder.

In a wet lithographic system, the non-image areas are hydrophobic and the required ink repellency is determined by a wetting solution (or "fountain") prior to or in conjunction with inking. By first applying to the plate. The ink-repellent dampening liquid prevents ink from adhering to non-image areas, but does not affect the lipophilic nature of the image areas.

[0004] Both dry and wet lithographic printing plates generally consist of a printing surface disposed on some type of support, which does or does not contribute to the pattern of ink acceptance or rejection. In some cases.
For example, as disclosed in US Pat. No. 5,339,737, a laser-imageable lithographic printing structure is a first layer, or top layer, chosen for its affinity (or repulsion) for ink or ink repellent liquid. And the imaging below (eg, infrared, or “IR”)
A durable, strong, characterized by an imaging layer that is ablated in response to the radiation, and a reverse affinity (or repulsion) to the ink or ink repellent liquid below the imaging layer A substrate. When the imaging layer is ablated, the top layer is also weakened. By breaking the anchor to the underlying layer, the top layer can be easily removed during the post-imaging cleaning step, unlike that of the unexposed portion of the top layer to ink or ink repellent liquid. An image spot with affinity is generated. In this type of structure, as in many traditional light-exposure configurations, the substrate is a heavy polymer film that accepts the ink and provides the necessary strength and durability to the structure. It imparts properties. However, obtaining such quality would involve not only material costs but also the cost of manufacturing equipment capable of handling such films.

[0005] US patent applications 08 / 700,287 and 08/75
No. 6,267 discloses wet and dry lithographic printing members comprising an inorganic metal layer. Such layers exhibit both hydrophilicity and substantial durability, even at very thin application levels, and are ablated by absorption of imaging radiation, thereby facilitating direct imaging without chemical development. . They are also used to form optical interference structures, which provide color and also absorb imaging radiation and are ablated in response to imaging pulses. Wet lithographic printing members based on this concept can include a protective layer that provides protection against handling and environmental damage, which increases the shelf life of the plate and carries debris generated by ablation. This layer is washed away during the printing preparation step, effectively cleaning the plate and disappearing without the need for a separate removal step. However, also in this case, such a printing member assumes a heavy polymer substrate.

[0006]

Some applications require greater dimensional stability than can be provided by plastic films. One such application is a special type of web printing, typically used by newspaper publishers, where no clamping mechanism is provided to hold the printing plate against the plate cylinder. Instead, the leading and trailing ends of each of the plates are bent and inserted into the slots provided in the corresponding cylinder, so that the plate is brought into contact with the cylinder surface by the mechanical bending action of this bent end. Is held. In the case of films and plastic materials, the shape retention and physical strength required to cope with such use in a printing press cannot easily be obtained. For example, it is possible to provide a polyester substrate with a relatively permanent bend by using heat curing equipment, but such techniques are cumbersome and costly. For such applications, the plastic film substrate is typically, for example, a U.S. Pat.
No. 5,188,032, the entire disclosure of which is incorporated herein by reference herein, is laminated to a sturdy metal support.

It is also possible to use a metal sheet directly as a substrate, as is usually done for large plates. The dimensional stability of plastic or film based plates tends to decrease with size unless the thickness of the substrate is increased. However, depending on the size of the plate, the increase in thickness required to maintain acceptable stiffness can make the plate cumbersome, uneconomical, or both. In contrast, in the case of metal substrates, at relatively moderate thicknesses, a high degree of structural integrity can be provided.

[0008] Of course, metal supports and substrates are more expensive than corresponding plastic products and require special rugged equipment. These are substantially unaffected after prolonged operation of the printing press, but form part of the plate structure and are integrally bonded to other layers of the plate, Reuse is impossible.

[0009]

According to the present invention, provision is made for reuse of a plate substrate or support. The plate substrate or support can be a metal sheet that can be secured (eg, using a clamp or bent) to a plate cylinder, or alternatively, is a surface that is permanent on such a cylinder. be able to.
In this way, the traditional "plate" will be replaced by a thin, easily manufacturable printing member that is separated from the support after use. In one approach, the printing member has a printing structure for receiving a lithographic printing pattern, with an adhesive layer underneath the structure. If this printing member is applied to the metal surface of a plate cylinder or other support,
The adhesive holds the printing member to the support with sufficient strength to prevent relative movement between the two during printing. In this way, the alignment between the printing members associated with the separate printing stations (sequentially encountering the recording medium to which the ink is applied) can be completely maintained. When the printing operation is completed, the printing member is peeled off the support and recycled or
Or it is discarded. In other words, regardless of the strength with which the alignment is maintained, the adhesive does not prevent peeling of the printing member from the support and preferably does not substantially leave any residue on the support.

It should be emphasized that the printing member may be in the form of a traditional cut sheet, or may be in some other form, such as a roll applied to the support piece by piece. . For example, such rolls can be contained inside a cylinder and are incrementally wound around the outer surface of the cylinder each time a printing operation is completed. See, for example, U.S. Patent No. 5,355,795.

In another embodiment, the adhesive is of the heat-sensitive type and loses adhesion with increasing temperature. The adhesive-backed printing member is applied to a support (and, if necessary, heated and then cooled to produce the bond), and printing is performed in the usual manner. The support is heated to facilitate removal of the printing member.
Preferably, the surface of the support and the layer of printing member carrying the adhesive are such that upon heating the adhesive is better retained on the printing member, thus minimizing residue on the support. To be elected.

In a third embodiment, the printing member is held by negative pressure on the outer surface of a porous cylindrical support (eg, a plate cylinder of a lithographic printing press). That is, the vacuum applied to the interior of the cylinder acts through the radial holes, thereby holding the printing member (typically in the form of a sheet) against the outer surface of the cylinder. Since the printing members used in connection with this embodiment of the present invention are typically very thin (e.g., on the order of 0.001-0.002 inches), it is advisable to use a cylinder with a specially adapted configuration to avoid deformation of the held printing members. is necessary. For example, conventional vacuum-type plate holding systems typically have large spaced, relatively large diameter air passages that create indentations in the surface of the printing member. , Resulting in non-uniform printing. Thus, the present invention uses a cylinder having continuously and uniformly distributed small diameter holes that are present continuously over the entire surface of the cylinder (or at least the portion of the cylinder below the image portion of the printing member). This creates a very uniform holding force and avoids the concentration of pressure that can create depressions on the surface. After printing,
Positive pressure can be used to facilitate removal of used printing members.

The invention further comprises an on-board system for continuous and automatic application, imaging and removal of the lithographic material according to the invention.

The foregoing discussion may be more readily understood by considering the following detailed description of the invention in conjunction with the accompanying drawings. The drawings and the members shown there are not necessarily drawn to scale.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The printing member used in connection with the present invention can take many forms and is not limited in type or construction. For example, preferred printing members range from structures for traditional light exposure to printing members that are ablated or otherwise imaged by laser or spark discharge. Printing members suitable for being imaged by a laser discharge are described, for example, in US Pat.
Nos. 9,737 and 5,379,698, the entire disclosures of which are incorporated herein by reference. Typical structures include an oleophobic (for dry printing) or hydrophilic (for wet printing) surface layer and a thin metal underneath that is ablated in response to a laser imaging pulse. There is a three-layer printing member having a polymeric imaging layer and a non-ablationable, oleophilic (ink-receptive) substrate under the imaging layer. In the case of a two-layer printing member, an oleophobic or hydrophilic surface layer that can be ablated by laser discharge and a lipophilic substrate underneath that is not ablated.

In another preferred approach, the printing member comprises a surface layer based on some metallic material and an underlying lipophilic layer. This metal material is hydrophilic and durable and is suitable for wet plate structures. In one embodiment, the material is very thin (50-500
(Preferably 300 ° for titanium and titanium)) A metal layer, which may or may not exhibit a native oxide film surface when exposed to air. This layer is ablated in response to IR radiation, and the image is provided on the printing member through making a patterned exposure to the output of one or more lasers (see, for example, reference herein. As disclosed in U.S. Patent No. 5,385,092, the entire contents of which are incorporated herein by reference). The metal is preferably at least one d-block (transition) metal, aluminum, indium, or tin. In the case of mixtures, these metals are present as alloys or as intermetallics. The lipophilic layer can also be treated in various ways, thereby improving the adhesion to the metal layer. For example, plasma treatment of the surface of a film with a working gas containing oxygen (eg, a mixture of argon / oxygen) results in the addition of oxygen to the surface of the film, which is reactive with the surface layer metal. By doing so, the adhesion is improved. Oxygen, however, is not required for a successful plasma treatment. Other suitable working gases include pure argon, pure nitrogen, and argon / nitrogen mixtures. For example, Bernier et al. ACS Symposium Series
440, Metallization of Polymers, p. 147 (1990).

Alternatively, the printing member can include a metallic inorganic layer above the metallic layer. The metallic inorganic layer comprises at least one metal and at least one non-metallic compound or a mixture of such compounds. Like the underlying metal layer, this inorganic layer is one that absorbs imaging radiation and is ablated, so
Applied at a thickness of -2000mm. The metal component of the inorganic layer includes a d-block (transition) metal, an f-block (lanthanoid) metal, aluminum, indium, or tin;
Alternatively, it may be a mixture of any of these (alloys or intermetallic compounds if more specific compounds are present).
Preferred metals include titanium, zirconium, vanadium, niobium, tantalum, molybdenum,
And tungsten. The non-metallic component can be one or more of the p-block elements boron, carbon, nitrogen, oxygen and silicon. The metal / non-metallic compound herein may or may not have a definite stoichiometry, and in some cases is an (e.g., Al-Si compound) alloy. Preferred metal / non-metal combinations include Ti
N, TiON, TiOx (0.9 ≦ x ≦ 2.0), TiAlN, TiAlC
N, TiC, TiCN, and the like.

In an embodiment of the wet plate wherein the metal or metallic inorganic layer is the top layer on the surface, the printing member also comprises
A protective layer applied thereon can be included. The material forming the protective layer preferably comprises a polyalkyl ether compound, the molecular weight of which depends on the mode of application, the mode and the conditions for the production of the plate. For example, when applied or applied as a liquid, the polyalkyl ether compound may have a relatively high average molecular weight (ie, at least 600) if the plate is heated during manufacture or subjected to heat during storage and transport. Have. Otherwise, it may have a lower molecular weight. The liquid to be coated must also exhibit sufficient viscosity to facilitate uniform coating at the appropriate application weight for the material to be coated.

A preferred formulation for the aqueous coating is polyethylene glycol (PE) having an average molecular weight of about 8000.
G) Consists of a combination of 80% by weight and 20% by weight of hydroxypropyl cellulose acting as a thickener. The formulation according to this specification is 4.4 parts by weight of Pluracol 8000 (BAS, Mount Olive, NJ, USA)
F) and 1.1 parts by weight of Klucel G
Alternatively, it can be prepared by combining 99-G "FF" grade hydroxypropylcellulose (commercially available from Hercules, Wilmington, Del., USA). These ingredients are mixed together as a dry powder, and the mixture is added slowly at 50-55 ° C. with 28 parts by weight of water with vigorous stirring so that the powder becomes wet during the addition. While maintaining the temperature at 50-55 ° C, the mixture is stirred for 20-30 minutes, thereby wetting the Klucel particles and dissolving Pluracol. At this point, 66.5 parts by weight of cold water (approximately 5-10 ° C.) are added in one portion to bring the temperature of the mixture to near or below room temperature. Stirring is continued for 1-2 hours until dissolution is complete. The viscosity of the solution is measured at about 100 cP.

Other materials and formulations can also be used to advantage. For example, the polyalkyl ether can be replaced with a polyhydroxyl compound, a polycarboxylic acid, a polysulfonamide, or a polysulfonic acid, or a mixture thereof. Gumming agents and fountains found in gum arabic or commercial plate finishes can also be used to provide a protective layer. Varn Products Co in Auckland, New Jersey, USA
The plate cleaning agent sold under the trade name TRUE BLUE and the dampening water sold under the trade name VARN TOTAL marketed by mpany are also suitable for this purpose. Similarly, a print from HoechstCelanese in Somerville, NJ, USA
FPC product available from the ING Products Division, G-7A- "V" -COMB, a fountain solution available from Rosos Chemical Co., Lake Bluff, Illinois, USA, Allied Photo Offset, Hollywood, FL, USA Supply
Plate cleaners and scratch removers sold under the trade name VANISH by Corp., and plate cleaning solutions sold under the trade name POLY-PLATE, also available from Allied, are also suitable. Another finishing material that is also useful is polyvinyl alcohol applied as a very thin layer.

The protective layer preferably provides its role, namely protection against damage due to handling operations and environmental factors, extends the shelf life of the plate by shielding the plate from airborne contaminants, and is produced by imaging. It is applied with a minimum thickness according to its role of taking in debris. If the protective layer can be made thinner, the protective layer can be washed out more quickly in preparation for the printing press, the roll-up time can be reduced, and the influence of the protective layer on the imaging sensitivity of the plate is reduced.

In a preferred configuration of the invention, the printing member comprises a thinner substrate layer than a conventional substrate. For example, a polyester film, a typical ink receptive material used in lithographic plate structures, can be used at a thickness of 0.001 inches or more. The preferred thickness range is 0.001 to 0.002 inches. Of course, larger or smaller thicknesses may be appropriate for different applications. For example, a tougher polymer material can be used with a smaller thickness.

Referring to FIG. 1, there is shown the basic approach of the present invention for adhesively securing a thin print member to a reusable surface. Adhesive backing102
The printing member 100 includes a cylindrical support (eg, a stainless steel or aluminum plate cylinder) 106
(Eg, stainless steel) carrier 110 which is applied directly to, or alternatively, the outer surface 104 of the
Applied to the surface 108 of For example, carrier 110 has a pair of edge tabs (one of which is indicated at 112) which are received in slots in cylinder 106 or by conventional clamps located within cavity segment 115 of the cylinder. Accepted.

This is clearly shown in FIG. FIG. 2 also shows the features of the printing member 100 in more detail. The tab at the edge of the carrier 110 is received in a pair of clamps 120a, 120b. The printing member 100 comprises a printing structure, generally designated 122, and an adhesive layer 124. The printing structure 122 may be comprised of a plurality of co-operating layers, which are responsive to actinic radiation or imaging (e.g., IR) laser pulses and, if necessary, after-treatment, to form ink and / or dampening fluids. It has a region pattern in image units that shows different affinity for the liquid. Typically, as shown in FIG.
The print area 130 of the print member 100, that is, the surface portion of the print member that actually receives the pattern in image units, is a partial area when viewed from the entire print member surface.

In the first and second embodiments, shown schematically in FIG. 2, the printing member 100 includes a printing structure 122 for receiving a lithographic printing pattern and a lower side of the printing structure 122. And an adhesive layer 124. In a first embodiment, the printing member 100 is applied to a metal surface of a plate cylinder or other support. The adhesive layer 124 is pressure sensitive and holds the printing member with sufficient strength against the carrier 110 (or the surface of the cylinder 106),
Prevents relative movement between them during printing. The adhesive, however, is weak enough to allow the printing member 100 to be peeled from the carrier 110 when the printing operation is completed, preferably without leaving any substantial residue. Useful adhesives also resist the effects of chemical reactants (fountains, plate cleaners, and / or ink solvents) that are commonly encountered in printing.

Suitable adhesives for this purpose include acrylic materials, such as those formulated for repeated application and removal. Since the surface area of the printing member 100 is very large, relative movement as a whole can be substantially prevented even when the adhesive force is moderate. In one exemplary form of this embodiment, a double-sided coated 4560 polyester film tape marketed by International Tape Co., Wyndham, NH, USA is applied to the back (polyester) surface of a wet lithographic printing plate (tape). The composite structure is applied to a plate cylinder of a four-color lithographic printing press, with the surface for permanent bonding of the polyester facing the polyester layer). When printed on this plate, the alignment was found not to be disturbed. The less viscous side of the 4560 product (contacting the carrier or plate cylinder) is an acrylic adhesive, having an adhesive value of 16 ounces per inch width and a viscosity value of 4.0 inches. However, in commercial practice, the adhesive is applied as a one-sided coating,
It is generally preferred to apply below the lower layer of the printing structure 122. Commercially available forms of printing members have a backing lining underneath the adhesive layer 124, which the user will remove immediately prior to application. However, the use of double-sided coating materials is not without advantages. 4560 due to the thickness of the tape (about 0.004 inches)
Plate to which the product was applied (US Patent Application No. 08 / 700,287
It has been found that Ti / TiN plates) exhibit good scratch resistance. Accordingly, this adhesive is used as a deformable layer, and is incorporated herein by reference in its entirety.
According to 4,291, it is possible to prevent scratches.

In, Wyndham, New Hampshire, USA
Successful results have also been achieved by using a double-sided coated 550 polyester film tape marketed by ternational Tape Co. applied to the back of a wet printing plate. The less viscous side of the product has an adhesion value of 10 ounces per inch width and a viscosity value of 4.0 inches. However, in this case, the chemical resistance is not suitable for long-term operation.

In a second embodiment, the adhesive layer 124 is a thermo-responsive material. When applied (either directly or after a heating and cooling cycle), this adhesive prevents the printing member 100 from moving relative to the carrier 110 (or the outer surface of the cylinder 106) during printing between them. But is peeled off by heating the surface to which it is applied. Thus, the cylinder 106 has an associated selectively activatable heating unit 135, which is connected to the outer surface of the cylinder (and also the carrier 110, if used due to heat conduction) or other plate. The carrier is heated to a temperature at which the printing member 100 can be conveniently removed. Preferably, the formulation of the adhesive is such that the adhesive adheres preferentially to printed structure 122 over the surface of carrier 110 or cylinder 106 (and / or prints). The bottom surface of structure 122 is so treated).

The heat-responsive adhesive 124 is made of polyurethane,
A polyamide (or copolyamide), ethylene vinyl acetate, polysilane (which can be applied, for example, by plasma activating the polyester surface prior to depositing hexamethyldisiloxane), or other,
Any thermally responsive material that loses internal cohesion at convenient operating temperatures, for example, 200-350 degrees Fahrenheit. In order to facilitate that the adhesive mainly remains on the print structure 122 upon removal of the print structure 122, the print structure 1
22 bottom surfaces can be treated. Typically, this treatment involves roughening the surface, improving the adhesion by forming a three-dimensional topology, and the like. In one approach, the lower layer of the printing structure 122 is a polymer (eg, polyester) and the bottom surface is treated by a plasma discharge. Of course, other forms of surface roughening (eg, by mechanical means) may be better for other materials or for different applications, and those skilled in the art will be able to perform this without undue experimentation. , The most appropriate technology can be easily identified. Alternatively, a “tie” coating that exhibits an affinity for the thermo-responsive adhesive may be applied to the bottom surface of the printed structure 122 and the adhesive applied to the adhesive coating. it can. Metallization with titanium, for various adhesive materials,
Produces an advantageous binding coating.

For this embodiment, it is particularly preferred to use a polished or unpolished stainless steel carrier 110 (or cylinder 106) to minimize affinity for the heated adhesive. However, as another alternative (or in addition to processing the printed structure 122), the cylinder 106 or carrier 110 can be treated to facilitate stripping. For example, a plasma may be applied to a metal surface to remove oil, and then a fluoropolymer or silane may be deposited on the surface using a plasma (for example, a plasma-activated decomposable siloxane such as hexamethyldisiloxane). By coating).

The printing structures according to the first and second embodiments described above can be designed for manufacture and use in roll form. Figures 3-6 show in detail a suitable configuration suitable for this type of configuration. FIG. 3 shows a dry-printed structure using a surface that also acts as a release layer,
Two adjacent turns 150 and 152 are shown. This printing structure, shown at 150, 152, includes a first layer 160 of an ink-repellent silicone or fluoropolymer and an imaging layer 162 that is ablated in response to imaging radiation (eg, according to US Pat. No. 5,379,698). Thin metal such as titanium applied at 200, or less, or US Patent No.
And an ink-receiving substrate 164, for example, a polyester film having a thickness of 0.001 inches or less.
Under the substrate 164, a pressure-sensitive adhesive layer 166 is placed. This adhesive layer 166 does not adhere to the first layer 160, and thus the first layer 160 has a release surface that allows the first layer 160-adhesive layer 166 to be unwound continuously. Will bring. In this case, too, the adhesive layer 166 is a U.S. Pat.
Configurable to provide a cushioning effect according to US Pat. No. 4,291.

FIG. 4 shows two adjacent turns 180,18 of a wet-printed structure using the technique of US patent application Ser. No. 08 / 756,267.
2 is shown. The printed structure includes a hydrophilic barrier layer 190, which itself is preferably at least one compound selected from the group consisting of polyalkyl ethers, polyhydroxyl compounds, polycarboxylic acids, polysulfonamides, and polysulfonic acids. Consists of The structure also includes a heat-resistant hydrophilic layer 192 comprising a compound of at least one metal and at least one non-metal, the at least one non-metal being composed of boron, carbon, nitrogen, silicon and oxygen. Selected from the group (eg, titanium nitride or titanium nitride on titanium) and ablated in response to imaging radiation. The printing structure further includes an ink receptive substrate 194, which can be, for example, a polyester film having a thickness of 0.001 inches or less. Under the substrate 194, a hot melt adhesive layer 1
96 are placed. The adhesive does not exhibit any substantial viscosity until heated, and thus does not adhere to the hydrophilic barrier layer 190 at room temperature. Again, this lack of adhesion allows the hydrophilic barrier layer 190-adhesive layer 196 to be unwound continuously from the roll.

However, the lack of viscosity is not absolute, and most hot melt adhesives are expected to leave some small residue on the hydrophilic barrier layer 190. However, this barrier layer is specially formulated to be washed away in the preparatory stage of printing, effectively cleaning the plate and disappearing with the carried adhesive residue.

FIG. 5 shows an alternative to the embodiment of FIG. 4, in which a release liner 198 is included. This liner allows the adhesive layer 200 to be used with virtually any desired adhesive. The liner 198 can be, for example, polyester coated with silicone on the side that contacts the adhesive layer 200. The uncoated side contacts the hydrophilic barrier layer 190 when wound on a roll, but does not adhere to this layer. Alternatively, the liner 198 can be any other inert material that does not interact with either the adhesive layer 200 and the protective hydrophilic barrier layer 190. It should be noted that the protective layer 190 in this structure is optional and can be omitted if desired.

This technique requires removal of the release liner prior to lamination (or other forms of attachment) to the metal support, but this technique is very common. And can be applied to various other types of printing structures. For example, liner 198 and adhesive layer 200 can be applied to a wet plate structure according to US Pat. No. 5,339,737. Such structures include, for example, polyvinyl alcohol or other hydrophilic polymeric material as a surface layer, and an imaging layer (eg, a thin metal or polymeric layer as described above) that is ablated in response to imaging radiation. And an ink receiving layer (eg, a polyester substrate). Adhesive layer 200
Is permanently applied to the underside of the polyester layer (but can be removed from the support to which the structure is applied, as described above), and a release liner 198 is placed underneath the adhesive layer 200. I will

Referring now to FIG. 6, there is shown one turn of the print structure that can be wound on a roll. This structure also uses a release material, but is unwound while exposing the adhesive layer. The illustrated structure includes a hydrophilic protective layer 190 and a heat-resistant hydrophilic layer 192, and also includes a temporary support layer 210 upon which other layers are built. The support layer 210 can be made of inexpensive paper sheets or polymeric materials, and is preferably also recyclable. Release layers 212a, 212b are applied to both sides of support layer 210. The function of the release layer 212a is to prevent adhesion to the adhesive layer 214, and therefore this release layer 212a may be omitted depending on the nature of the support layer 210 (or if the adhesive layer 214 is a hot melt adhesive). can do. Release layer
The function of 212b is to allow the support layer 210 to be stripped from the protective layer 190 after applying the structure to a support. In one approach, release layer 212b is a release layer of silicone formulated to perform release in a controlled manner. Alternatively, release layer 212b is a thermally activated material, such as a wax. For example, carnauba wax coatings used in hot stamping foil applications are typical of suitable materials. This wax is solid at room temperature, but liquefies when heated, making removal of the support layer 210 easier. Since the protective layer 190 is hydrophilic, it is desirable that the release layer 212b also exhibit some degree of hydrophilicity. In fact, if the wax is sufficiently hydrophilic, it can serve as both a release layer 212b and a protective layer 190 as a single layer.

The support layer 210 acts as a substrate for the manufacture of this structure. Protective layer 190, heat-resistant hydrophilic layer 19
2. The substrate 194 and the adhesive layer 214 are sequentially deposited or coated on the release layer 212b (or directly on the support layer 210). In use, the adhesive layer 214 is applied (removably) to a metal support, and the support layer 210 is peeled from the structure to allow printing. Any residue of the release layer 212b is carried on the protective layer 190 and is washed away in a preparation stage for printing.

FIG. 7 illustrates an apparatus, generally designated 250, that applies a plate material in roll form to a metal sheet 255 that acts as a reusable support. Can be used to apply. The continuous processing path through which the sheet 255 is sequentially passed is the entrance 257
, A surface conditioning chamber 260, a clean air (clean air) source 262 for controlling the atmosphere in the chamber, an application chamber 265, and an outlet 267. As the sheet passes through the surface conditioning chamber 260, it first encounters the surface treatment unit 270. The device can handle surface dust removal and / or corona treatment. In addition, the unit 270 can detect when used printing structures are present on the sheet 255 and use a knife or blade (and depending on the type of adhesive used). The used material can be peeled off (by activating the heating lamp).

A pair of drive rollers 272 form a nip for supplying the sheet 255 to the application chamber 265.
Located in the chamber 265 is a cassette or roll 275 of adhesive-backed plate material of the present invention.
It is. This plate material 275 is used for a pair of application rollers 280.
(Which can be heated if a hot melt adhesive is used). These rollers 280 apply a plate material 275 to the sheet 255, which is cut to a predetermined length by a blade 285.
These finished plates exit the device 250 via outlet 267.

The roll of adhesive material is also applied directly and automatically to the plate cylinder of the printing station in the printing press, as shown in FIG. 8, rather than to the intermediate carrier as described above. be able to. The components of the printing press include a plate cylinder 300, a blanket cylinder 302 in rotational contact with the plate cylinder 300, and an inking system 305. Inking system 305 transfers the ink onto the imaged plate adhered to plate cylinder 300. In a dry system, the ink is transferred directly to the plate, whereas in a wet configuration, the inking system 305 includes means for applying a dampening solution to the plate prior to inking. Blanket cylinder
302 receives the ink in a pattern of the image unit of the plate and transfers the pattern to a recording medium (not shown).

Plate material 306 is applied to cylinder 300 by applicator 308, which includes a roll 310 of plate material 306. Plate material 306 is release liner (as shown in Figure 2-4)
If not included, the plate material is withdrawn from the supply roll 310 and is retracted by the retractable tensioning and application roller 312 into the cylinder 3.
Apply directly to the 00 surface. Once the entire surface of the cylinder 300 has been covered, a blade (not shown) is drawn axially across the plate material 306 and the resulting end is forced against the cylinder 300 by rollers 312. Pressed. Preferably, the leading and trailing edges of the applied material do not overlap. Rather, the applicator 308 cuts the plate material 306 such that a slight circumferential gap is maintained between the ends (exposing the surface of the cylinder 300).

The plate material 306 is used as the release liner 315 (FIG. 5).
And the take-up roller 31
8 rotates to remove liner 315 from plate material 306 as plate material 306 unwinds. In operation, the tip of the release liner 315 is initially secured to the take-up roller 318, and the rotational speed of the roller 318 is such that the amount of release liner 315 to be wound matches the amount of plate material 306 supplied. Is adjusted to

After the application of plate material 306 to cylinder 300 is complete, imaging system 320 applies a lithographic image to the plate. Preferably,
This imaging system is described, for example, in U.S. Pat.
This is an ablation apparatus using a laser as described in No. 092. Ink is applied to the imaged plate, as described above, and the plate is stripped from cylinder 300 by remover 322 after use.
The removal device 322 may include a retractable blade 325 that, when stretched, will allow the plate material 30 to extend.
6 is biased along the surface while grazing the surface, engaging the tip of the plate material and displacing this material into the cylinder.
By lifting from 300 and continuing rotation of the cylinder, the plate material can be stripped over its entire length. The system may also include a cylinder cleaner 330. This engages the cylinder 300 after the plate material has been stripped to remove adhesive residue from the cylinder surface. Suitable cleaning devices may be conventional in the art and typically include a rotating brush, a roller of foam material, etc.
Further, a cleaning liquid or a solvent can be used.

Alternatively or additionally, a heater 135 (see FIG. 1) may be associated with the cylinder 300 to accommodate a plate material containing hot melt adhesive. This heater is activated after imaging and use of the applied plate material segment, and allows the removal device 322 to conveniently strip the plate material.

In a third embodiment of the present invention, the printing structure is itself mounted directly to the porous cylinder by negative pressure. A suitable configuration is shown in FIG. The cylinder 400 shown therein is continuous and uniform over its entire surface 402 (or at least over the surface portion 402 below the image portion of the member applied to the printing structure). Have small diameter holes distributed in the holes. The body of cylinder 400 is sealed and a vacuum pump 404 located inside or outside of cylinder 400 (but in sealed fluid communication with the interior of cylinder 400) evacuates air from inside the cylinder. To generate a negative pressure that holds the printed structure wound on surface 402 with sufficient force to prevent it from moving circumferentially. The vacuum pump 404 also
It can also operate in the opposite direction, thereby assisting in the initial positioning of the printing structure and removal after use.

The cylinder 400 can be of any type, as long as it has the required porosity and resistance to deformation. The optimal size and density of the holes for a particular application is determined by the thickness and stiffness of the printing structure applied to it, as well as the need for pneumatic transport sufficient to generate a suitable negative pressure. Generally, the holes are less than 1 mm in diameter, and are likely to be substantially smaller. For example,
Tubular materials supplied by Mott Metallurgical Corp. have uniformly distributed pores with an average diameter possibly on the order of 1 micrometer or less.
The US Filter Corp.'s Membralox Division offers multi-channel ceramic membranes and Rhone-Poulenc offers ceramic and silicon carbide membrane elements. Pall Filter Corp. sells ceramic, silicon carbide, and porous metal sheets and tubular structures similar to those of other manufacturers. A variety of sintered metals with various pore sizes are also available. Any of these can be used as a support, either directly or as an outer layer around a metal mesh scaffold (or, conveniently, a perforated tube).

In use, the printing member (actually the printing structure 122) is wrapped around the surface 402 of the cylinder 400 and the vacuum pump 404 is energized until a vacuum corresponding to sufficient holding strength is achieved. Is done. Preferably, the vacuum pump 404 is provided with a suitable feedback circuit, whereby the pump is automatically stopped when a user-selected holding strength is reached, and only when necessary to maintain this level. Re-energize. After printing, the interior of the cylinder 400 is vented (or the vacuum pump 404 is operated in the reverse direction) to facilitate easy removal of the printed structure. It should be emphasized that the printing structure 122 can be wrapped around the entire circumference of the cylinder 400 to create a seamless or nearly seamless printing member.

FIG. 10 illustrates one form of the cylinder shown in FIG. 9, which is configured to receive and supply plate material therein. The cylinder 450, shown in cross-section in this figure, includes first and second side plates. The inside surface of one of the side plates seen in this drawing is shown at 452. The body of the cylinder defines an annular chamber 455, which does not form a complete circle, but is arcuate in cross section. This chamber 455 is closed at both ends, and a space or gap 460 is formed between them. The outer edge 462 of the chamber 455 is porous as described above. The side edges 465, 467 and the inner edge 470 are completely non-porous. A conduit 475 extends along the inner surface 452 of the side plate. One end of the conduit 475 is in fluid communication with the inside of the chamber 455, and the other end is in fluid communication with a rotating vacuum union (not shown). This rotating vacuum union is on the outer surface of the illustrated side plate and connects the conduit 475 and the vacuum pump 404 (FIG. 9).

Inside the cylinder 450, a plate material supply spool 480 and a take-up spool 482 are arranged. These are constructed according to conventional techniques (e.g., U.S. Patent Nos. 5,355,795 and 5,657,692, which are incorporated herein by reference in their entirety, and permitted U.S. Patent Application No. 08 / 597,040). ) To facilitate unwinding and winding up a sufficient amount of plate material 485 to cover outer surface 462 of cylinder 450. Thus, in operation, plate material from the supply spool 480 emerges from the gap 460 and is passed past the edge 467 of the chamber 455 to the outer surface.
462 and then re-enters cylinder 450 over opposite edge 465 and takes up spool 482
It goes up. The vacuum pump 404 has an outer surface 462
The plate material 485 is biased to pull tightly against (avoids the need for a mechanical tensioning mechanism to keep the plate material from slipping). Once a given segment of the plate material has been imaged and fully used, the chamber 455 is vented or, preferably, the vacuum pump 404 is operated in the reverse direction to allow the plate material to easily move on the outer surface 462. Is allowed to move. Rollers 480, 482 are advanced so that new segments of plate material 485 are brought onto outer surface 462, and are ready for imaging and use. Imaging is accomplished using an imaging system as shown in FIG. 8, where again the plate material 485 receives the ink from the inking system and transfers the ink onto a blanket cylinder according to the image thereon.

An alternative arrangement for providing complete circumferential coverage without gaps or voids is shown in FIGS. This configuration can be used for the more traditional mandrel configuration. The embodiment shown illustrates a tubular vacuum manifold 50, as shown in FIG.
Contains 0. The manifold comprises a series of axial grooves or channels 502, consisting of a steel or other metal body, circumferentially spaced and carved in the inner surface 504.
It has. These channels 502 are
It only partially penetrates the annular thickness of, and extends completely to both ends of the manifold 500. A series of openings 506 distributed along the axial length of the channel 502 penetrate the manifold 500 completely,
Concave surface of channel 502 and outer surface of manifold 500
It extends over the entire thickness between 510.
Thus, the outside of the manifold 500 is in fluid communication with the channel 502 by the opening 506. The opening 506 need not be particularly small. For example, they may be several millimeters in diameter.

Referring to FIG. 12, the manifold 500 includes a conventional printing mandrel 515 that completely surrounds it.
Is in tight and airtight contact. A porous cylindrical member 400 as described above concentrically surrounds the tubular manifold 500. Finally, the printing structure 122 is
Wrapped around the outside surface of the The ends of this printed structure 122 can abut tightly against each other and are effectively joined, creating only a few seams 520.

At one axial end of the structure shown in FIG. 12, the manifold 500 terminates in a plate cover (not shown) that seals the end of the channel 502. At the opposite end, a toroidal chamber (also not shown) forms a plenum over the open end of channel 502. A rotating vacuum union is in fluid communication with the chamber and couples the channel 502 with the vacuum pump as described above. When the vacuum pump is energized, air is drawn through channel 502 and opening 506, creating a negative pressure on plate structure 122. However, due to the presence of the porous cylinder 400, the plate structure 122 is not sucked into the large-diameter opening 506. Although the vacuum is not uniform around the circumference of the cylinder 400 and is locally concentrated at the portion of the opening 506, the openings are themselves uniformly distributed along the surface 510 of the manifold 500, The pull on plate structure 122 is symmetric.

[0053]

As described above, the present invention provides an improvement to a lithographic printing system for providing a reusable application surface. The terms and expressions used herein are words of description rather than limitation, and the use of such terms and expressions is not limited to the features or parts thereof illustrated and described. There is no intention to exclude equivalents. Rather, within the scope of the claimed invention,
It will be appreciated that various modifications are possible.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a representative embodiment of the present invention;
Figure 4 shows an embodiment in which the printing member is attached to a cylindrical support, either directly or by a metal carrier that is itself clamped to the cylinder.

FIG. 2 is an end view of a lithographic printing structure having an adhesive layer and a carrier and cylinder assembly to which the printing structure is adhered in accordance with the present invention.

FIG. 3 is a cross-sectional view of a roll-shaped printing structure according to the present invention.

FIG. 4 is a sectional view of a roll-shaped printing structure according to the present invention.

FIG. 5 is a sectional view of a roll-shaped printing structure according to the present invention.

FIG. 6 is a sectional view of a roll-shaped printing structure according to the present invention.

FIG. 7 is a schematic view showing an apparatus for applying the structure shown in FIGS. 3-6 to a metal base.

FIG. 8 is a schematic diagram showing an on-machine application, imaging and removal system for an adhesive-based embodiment.

FIG. 9 is a perspective view of a porous cylinder to which a printing structure can be attached by negative pressure.

FIG. 10 is adapted for mounting the plate by negative pressure,
FIG. 4 is a sectional end view of a cylinder accommodating a supply roll and a take-up roll therein.

FIG. 11 is a partially cutaway perspective view of a vacuum manifold tube.

FIG. 12 is an end view of a cylinder using the tube shown in FIG. 11 and adapted for mounting a plate by negative pressure.

Continued on the front page (72) Inventor Ernest W. Ellis, Massachusetts, USA 01451, Harvard, Old Meadow Lane 4 (72) Inventor, Thomas E. Lewis, New Hampshire, USA 03826, East Hampstead, Pilgrim Circle 27 (72) Inventor Robert Howard East Fifty Seventh Street 303, New York, 10022, New York, USA

Claims (39)

[Claims] 1. A method according to claim 1, Means for supporting a lithographic printing sheet having a printing area, said means comprising a cylindrical body, the body extending through the body and continuously and uniformly distributed over the body. Wherein the distribution of the holes in the body occupies at least an area coextensive with the printing area; b. A printing system comprising means for generating a negative pressure inside said body for pulling a print sheet wound around said body against said body. 2. A removable printing member adapted for use on a support member, comprising: a. A printing structure for receiving a lithographic printing pattern, comprising a top layer and a bottom layer of a polymer; b. Overlying the exposed side of the bottom layer of the printing structure and adhering the printing structure to the support member sufficiently to prevent relative movement therebetween during printing. The printed structure is peelable from the support member, the adhesive does not exhibit substantial adhesion to the top layer, and the adhesive layer is the top layer. A printing member, wherein the printing structure is capable of unwinding when wound around a roll so as to face the printing member. 3. A removable printing member adapted for use on a metal support member, comprising: a. A printed structure for receiving a lithographic printed pattern, comprising a lowermost layer of a polymer; b. Overlying the exposed side of the bottom layer of the printing structure and adhering the printing structure to the support member sufficiently to prevent relative movement therebetween during printing. A printing member comprising a heat-responsive adhesive layer to be applied, wherein the adhesive is released by heating. 4. A method according to claim 1, wherein Means having a metal outer surface and supporting a lithographic printing member; b. Means for selectively heating at least the outer surface of said support means; c. A printing member adapted to be removably secured to said support means, said printing member comprising: i. A print structure for receiving a lithographic print pattern, comprising a lowermost layer of a polymer; ii. On the exposed side of the lowermost layer of the printing structure, gluing the printing structure to the support means sufficient to prevent relative movement between them during printing A printing system comprising: a heat-responsive adhesive layer to be applied; and the adhesive is a printing member that is peeled off by heating the outer surface of the support means. 5. The system of claim 1, wherein said support means is a metal cylinder. 6. The system of claim 1, wherein said support means is a metal sheet adapted to be secured to a plate cylinder. 7. The printing member according to claim 2, wherein said adhesive is an acrylic adhesive. 8. The system of claim 4, wherein said support means is a metal cylinder. 9. The system of claim 4, wherein said support means is a metal sheet adapted to be fixed to a plate cylinder. 10. The system of claim 3, wherein said adhesive is selected from the group consisting of polyurethane, polyamide, copolyamide, ethylene vinyl acetate, and polysilane. 11. A printing device comprising a removable printing member and a metal support member, said printing member receiving a lithographic printing pattern and including a lowermost layer of a polymer, said lowermost layer being on the exposed side thereof. Having a thermo-responsive adhesive that bonds the printing structure to the support member sufficiently to prevent relative movement therebetween during printing, wherein the adhesive is heated to A system wherein the lowermost layer of polymeric material of the printed member that is peeled off exhibits a greater affinity for the adhesive than the support member when heated. 12. The stem of claim 4, wherein said support means is stainless steel. 13. The printing structure comprising: a. A first layer of silicone or fluoropolymer; b. A second layer under the first layer and ablated in response to imaging radiation; c. An ink-receiving polymer layer underlying the second layer, wherein the adhesive does not exhibit substantial adhesion to the first layer, and the adhesive is the first layer. The printing member according to claim 2, wherein the printing structure is capable of being unwound when wound on a roll so as to face the printing member. 14. The printing structure comprising: a. A first layer; b. A second layer under the first layer and ablated in response to imaging radiation; c. A third layer below the second layer, wherein the first layer and the third layer have different affinities for at least one printing liquid selected from the group consisting of ink and ink repellent liquid. The printing member according to claim 2, further comprising a release liner that exhibits a property and is disposed below the adhesive layer. 15. The printing structure comprising: a. A first hydrophilic layer; b. A second hydrophilic layer underneath the first layer, wherein the first layer and the second layer are ablated in response to imaging radiation; c. An ink receptive third layer below the second layer, wherein the adhesive does not exhibit substantial adhesion to the first layer before heating, and the adhesive is 4. The printed structure is free to unwind when wound on a roll so as to face the first layer.
Printing members. 16. The printing structure comprising: a. A first hydrophilic layer; b. A second hydrophilic layer underneath the first layer, wherein the first layer and the second layer are ablated in response to imaging radiation; c. An ink receptive third layer underlying the second layer, wherein the printed structure further comprises a support layer removable from the first layer, wherein the adhesive supports the removable support. The printed structure is free to unwind when the adhesive does not exhibit substantial adhesion to the layer and the adhesive is wound on a roll facing the first layer; The printing member according to claim 3. 17. The printing structure, comprising: a. A first hydrophilic layer; b. A second hydrophilic layer underneath the first layer, wherein the first layer and the second layer are ablated in response to imaging radiation; c. An ink receptive third layer underlying the second layer, wherein the printed structure further comprises a support layer removable from the first layer, wherein the adhesive supports the removable support. The printed structure is free to unwind when the adhesive does not exhibit substantial adhesion to the layer and the adhesive is wound on a roll facing the first layer; The printing member according to claim 2. 18. a. Providing a means for supporting a lithographic printing sheet having a printing area, said means comprising a cylindrical body, said body comprising an internal volume;
Extending through the body and having holes that are continuously and uniformly distributed over the body; b. Wrapping a lithographic printing sheet around the body; c. Generating a negative pressure within the body to attract the print sheet to the body; d. A printing method comprising applying ink to the print sheet and transferring the ink to a recording medium in a pattern in image units. 20. a. Providing a printing member in roll form, the printing member comprising a printing structure for receiving a lithographic printing pattern, the printing structure comprising: (i) a top layer; The bottom layer,
(Iii) an adhesive on the exposed side of the lowermost layer, which adheres the printed structure to a support sufficient to prevent relative movement therebetween during printing. An adhesive layer, wherein the printed structure is peelable from the support member, the adhesive does not exhibit substantial adhesion to the uppermost layer, and the adhesive layer faces the uppermost layer. The printing structure being free to unwind when wound on a roll, b. Providing a support carrying the printing member; c. Unwinding one segment of the printing member from the roll and adhering the segment to the support; d. Printing by applying ink to the segments and transferring the ink to a recording medium in a pattern in image units; e. Separating the printing member segments from the support after the printing step. 20. a. Providing a metal support; b. Providing a printing member adapted to be removably secured to the support, the printing member comprising a printing structure for receiving a lithographic printing pattern, wherein the printing structure is a polymeric material. Providing a lower layer and a thermo-responsive adhesive layer on the exposed side of the lowermost layer; c. Applying the adhesive-provided side of the lowermost layer of the polymer of the printing member to the support, and adhering the printing member to the support; d. Printing by applying ink to the printing member and transferring the ink to a recording medium in a pattern in image units; e. Heating the support after the printing step to facilitate peeling of the printing member from the support. 21. a. Means for supporting a lithographic printing sheet having a printing area, said means comprising a cylindrical body, which body is continuous and uniform over the surface, extending through the body and over the body; And the distribution of the holes in the body occupies at least an area coextensive with the printing area, b. A printing system comprising means for generating a negative pressure inside said body for pulling a print sheet wound around said body against said body. 22. The system of claim 21, wherein said support means is a metal cylinder. 23. The system of claim 21, wherein the means for generating a negative pressure is further configured to selectively generate a positive pressure to facilitate removal of the printed sheet. 24. The system of claim 21, wherein said holes have an average diameter no greater than 1 mm. 25. The system of claim 21, wherein said holes have an average diameter no greater than 1 micrometer. 26. a. Means for supporting a lithographic printing sheet having a printing area, said means comprising a chamber having an arcuate cross section and an outer surface, said chamber defining an internal cylinder volume and an opening to this volume, said outer surface being Having holes that extend through the outer surface and are continuously and uniformly distributed over the surface, wherein the distribution of the holes on the outer surface occupies at least an area coextensive with the printing area; b. A printing system comprising means for generating a negative pressure inside said body for pulling a print sheet wound around said body against said body. 27. The chamber according to claim 27, wherein the chamber is made of metal.
26 systems. 28. The system of claim 26, further comprising imaging means for imprinting a lithographic image on said print sheet. 29. The apparatus of claim 29, further comprising a print sheet supply means and a take-up means disposed within the inner cylinder volume, wherein the supply means winds the print sheet via a transport path extending around an outer surface of the chamber. 27. The system of claim 26, wherein the system delivers to a pick-up means. 30. The system of claim 26, wherein the means for generating a negative pressure is further configured to selectively generate a positive pressure to facilitate removal of the printed sheet. 31. The system of claim 26, wherein said holes have an average diameter no greater than 1 mm. 32. The system of claim 26, wherein said holes have an average diameter no greater than 1 micrometer. 33. a. A plate cylinder; b. Means for applying a lithographic printing material onto the plate cylinder, comprising an adhesive for bonding to the plate cylinder; c. Means for imprinting the image on the applied printing material; d. Means for removing said applied printing material after use. 34. a. Inking means for applying ink to the imaged printing material; b. A blanket cylinder for rotationally contacting the printing material carried on the plate cylinder and receiving the applied ink in an image-wise pattern.
34. The system of claim 33. 35. The system of claim 33, further comprising cleaning means for removing adhesive debris from said plate cylinder subsequent to removing said printing material. 36. The means for applying is configured to apply a lithographic printing material including an adhesive layer and a release liner thereon to the plate cylinder, and the means for applying. 34. The system of claim 33, further comprising means for removing the release liner as the printing material is applied to the plate cylinder. 37. The system of claim 33, further comprising means for heating said plate cylinder to assist in removing said printing material from said plate cylinder. 38. a. Means for supporting a lithographic printing sheet having a printing area, the means comprising: i. A cylindrical body, having continuous and uniformly distributed holes extending through the body, wherein the distribution of the holes in the body is at least as large as the printing area; An occupying body; ii. A series of axial channels disposed concentrically within the cylindrical body and having an annular thickness that penetrates the thickness, and are disposed along and extend through the thickness. A cylindrical manifold comprising a series of apertures establishing fluid communication between the channel and the cylindrical body, the channel having a closed end; iii. A mandrel having a continuous surface concentrically disposed therein and in gas-tight contact with said manifold; b. A printing system comprising means for creating a negative pressure in said channel to pull a printed sheet wrapped around said cylindrical body against said body. 39. a. Providing a means for supporting a lithographic printing sheet having a printing area, said means being a cylindrical body, having an internal volume and extending through said body, continuously and over said body; A step consisting of having uniformly distributed holes; b. Wrapping a lithographic print sheet around the body; c. Generating a negative pressure inside the body to attract the print sheet to the body; d. Applying an ink to the print sheet and transferring the ink to a recording medium in a pattern in image units.