Abstract: A method for making a flexographic printing master includes the steps of providing a flexographic printing support; providing an inkjet printing device; applying a mesa relief on the flexographic printing support with the inkjet printing device; and applying an image relief with the inkjet printing device on the mesa relief. A method for making a flexographic printing master includes the imaging apparatus.

Abstract: A polymerizable photoinitiator is represented by Formula (I): wherein R1, R2 and R3 are independently selected from the group consisting of a hydrogen, an optionally substituted alkyl group and an optionally substituted aryl group or R1 and R3 represent the necessary atoms to form a five to eight membered ring; p, w, y and z are all integers with y representing a value 1 to 6; p representing the sum of w and z; p representing a value of 1 to 6; w=1 to (p?z) and z=0 to (p?w); L represents an optionally substituted (p+y)-valent linking group comprising 1 to 14 carbon atoms; A represents a radically polymerizable group selected from the group consisting of an acrylate group, a methacrylate group, a styrene group, an acryl amide group, a methacryl amide group, a maleate group, a fumarate group, an itaconate group, a vinyl ether group, an allyl ether group, an allyl ester group and a vinyl ester group; and X represents a photoinitiating moiety including at least one group capable of initiating a free radical p

Abstract: A method for making a flexographic printing master includes the steps of providing a flexographic printing support: applying image-wise on the flexographic printing support subsequent layers of radiation curable liquid by an inkjet printing device whereby one or more applied layers are immobilized using a curing device before one or more subsequent layers are applied, such that a relief with a top hat profile is obtained; and grinding the relief so that the height DT of a top hat segment is reduced. An imaging apparatus includes structure to perform the above method.

Abstract: Ink coalescence in inkjet printing is reduced by printing mutually interstitial images using an arrangement of multiple curing stations in combination with multiple printing heads.

Abstract: A sleeve segment for flexography has the shape of a sleeve with a first circular side containing a female registration element and a second circular side containing a male registration element. Also a method for manufacturing a flexographic sleeve segment, segmented sleeves and methods of flexographic printing.

Abstract: A UV radiation curable composition includes a cationic photoinitiator according to Formula (I) or (II): wherein R1, R2 and R3 independently represent a group selected from the group consisting of an aryl group and a heteroaryl group, with the proviso that R1, R2 and R3 are each substituted by at least one substituent including at least one cationically polymerizable group selected from the group consisting of an alkenyl ether, an epoxide and an oxetane; and P and Q independently represent the necessary atoms to form a substituted or unsubstituted 5 or 6-membered aromatic or heteroaromatic ring, with the proviso that at least one of P, Q and L is substituted by at least one substituent including at least one cationically polymerizable group, selected from the group consisting of an alkenyl ether, an epoxide and an oxetane; and L represents a group selected from the group consisting of a direct bond, O, S, SO, SO2, CR5R6, C(?O), S(?O), C(NR8) and NR7.

Abstract: A polymerizable Norrish Type II photoinitiators includes an optionally substituted benzophenone group or an optionally substituted thioxanthone group exhibiting improved compatibility with and solubility in radiation curable compositions. Radiation curable compositions and inkjet inks can contain these polymerizable Norrish Type II photoinitiators, exhibiting low extractable amounts of the photoinitiators and their residues after curing.

Abstract: A lithographic printing plate precursor includes a coating provided on a support having a hydrophilic surface, the coating containing thermoplastic polymer particles and an infrared radiation absorbing dye characterized in that the dye contains a substituent selected from bromo and iodo.

Abstract: A polymerizable Norrish Type II photoinitiator according to Formula (I): . Radiation curable compositions and inkjet inks containing the polymerizable Norrish Type II photoinitiator of Formula (I) exhibit improved compatibility with and solubility in radiation curable compositions and inkjet inks, and exhibit low extractable amounts of the photoinitiator and its residues after curing.

Abstract: A method of preparing a lithographic printing plate in which no pre-heat step is used comprising the steps of:—providing a lithographic printing plate precursor comprising a support and a photopolymerizable image-recording layer, the image-recording layer comprising a monomer and a binder;—image-wise exposing the precursor in an exposure unit;—off press developing the exposed precursor with an aqueous solution in a processing unit; characterized in that the ratio of the total amount of monomer to the total amount of binder is at least 1 and the time lapse between exposing an image-area of the precursor and contacting the image-area with the aqueous solution is at least 1 minute.

Abstract: A method for making a flexographic printing master includes a first step of providing a flexographic printing support; a second step of applying image wise with a first resolution a layer of a radiation curable liquid partially covering the printing side of the support; a third step of flood exposing the applied radiation curable layer to fully cure the layer; and a fourth step of image wise laser engraving the cured layer with a second resolution which is higher than the resolution of the second step. An imaging apparatus can perform the above method.

Abstract: A free radical curable liquid for inkjet printing of food packaging materials includes no initiator or otherwise one or more initiators selected from the group consisting of non-polymeric di- or multifunctional initiators, oligomeric initiators, polymeric initiators, and polymerizable initiators; wherein the polymerizable composition of the liquid consists essentially of: a) 25-100 wt % of one or more polymerizable compounds A having at least one acrylate group G1 and at least one second ethylenically unsaturated polymerizable functional group G2 different from the group G1; b) 0-55 wt % of one or more polymerizable compounds B selected from the group consisting of monofunctional acrylates and difunctional acrylates; and c) 0-55 wt % of one or more polymerizable compounds C selected from the group consisting of trifunctional acrylates, tetrafunctional acrylates, pentafunctional acrylates and hexafunctional acrylates.

Abstract: A method for making a positive-working lithographic printing plate includes the steps of: (1) providing a heat-sensitive printing plate precursor including on a support, having a hydrophilic surface or which is provided with a hydrophilic layer, a heat-sensitive coating; (2) image-wise exposing the precursor with heat and/or light; and (3) developing the exposed precursor with an aqueous alkaline developing solution including lithium ions at a concentration of at least 0.05% wt and a salt of an aliphatic carboxylic acid; wherein the molar ratio of the aliphatic carboxylic acid to the lithium ions is ?1.

Abstract: A method of coating a peripheral surface of a sleeve core with a radiation curable coating liquid including the steps of: supporting a sleeve core in a vertical position coaxial with a coating axis; providing an annular coating collar, supplying the coating liquid to the annular coating collar and moving the annular coating collar along the sleeve core in a vertical direction coaxial with the coating axis, thereby coating a layer of the coating liquid onto the peripheral surface of the sleeve core; wherein the coated layer of the coating liquid is cooled by the peripheral surface of the sleeve core to have a viscosity at the temperature of the peripheral surface of the sleeve core and at a shear rate of 10 s?1 which is larger than a minimum viscosity ?min, with: ? min = d 2 50 wherein d represents the thickness of the coated layer expressed in ?m, and ?min is expressed in mPa·s. Also, a coating device for performing the above coating method.

Abstract: A method for gumming a lithographic printing plate includes the steps of a) providing a lithographic printing plate including a lithographic image consisting of printing areas and non-printing areas, and b) jetting a gum solution with an inkjet printer to produce a hydrophilic protective layer on the non-printing areas. An inkjet printer includes a gum solution for producing a hydrophilic protective layer on the non-printing areas and a fluid for the formation of the printing areas of a lithographic image on a lithographic printing plate precursor.

Abstract: An image processing method includes a step of converting halftoned pixels of an image to be printed represented at a first lower tonal resolution into pixels represented at a second higher tonal resolution. Image processing is used on the pixels having a higher tonal resolution to reduce image quality artifacts when the pixels are printed at the first lower tonal resolution. In a preferred embodiment, the image processing includes error diffusion of a sigma delta modulation.

Abstract: A composition that is photopolymerizable upon absorption of light and/or heat, the composition including a binder, a polymerizable compound, a sensitizer, and a photoinitiator, characterized in that the composition includes, with respect to its non-volatile compounds, at least about 0.01 wt.-% of a polythiol compound and has a very high sensitivity and hardness.

Abstract: A multifunctional Type II photoinitiator according to Formula (I): wherein X represents a structural moiety according to Formula (II): wherein: A represents a Norrish Type II initiating group; and L represents a divalent linking group positioning the Norrish Type II initiating group A and the CR2R3-group in a 1-5 to a 1-9 position wherein position 1 is defined as the first atom in the aromatic or alicyclic ring of A to which L is covalently bonded and the position 5 to 9 is defined as the carbon atom of the CR2R3-group to which L is covalently bonded, with the proviso that L does not contain an amine. Radiation curable compositions and inks include the multifunctional Type II photoinitiator.

Abstract: A polymerizable Type II photoinitiator according to Formula (I): wherein: A represents a Norrish Type II initiating group; L represents a divalent linking group positioning the Norrish Type II initiating group A and the CR2R3-group in a 1-5 to a 1-8 position wherein position 1 is defined as the first atom in the aromatic or alicyclic ring of A to which L is covalently bonded and the position 5 to 8 is defined as the carbon atom of the CR2R3-group to which L is covalently bonded, with the proviso that L does not contain an amine. Radiation curable compositions and inks include the multifunctional Type II photoinitiator.

Abstract: A composition that is photopolymerizable upon absorption of light and/or heat, the composition including a binder, a polymerizable compound, a sensitizer, and a photoinitiator, characterized in that the composition includes, with respect to its non-volatile compounds, at least about 0.01 wt. % of a polythiol compound and has a very high sensitivity and hardness.