A lithographic printing plate precursor has a substrate comprising a hydrophilic surface and two opposing edges; a radiation-sensitive imagable layer, and optionally, a protective layer disposed over that layer. The precursor has a shear droop at each opposing edge, each shear droop having a shear droop depth Y of 20-200 m and a shear droop width X of 500-2000 m. The precursor also has a hydrophilic coating band extending from each of the two opposing edges inwardly along the hydrophilic surface independently to provide a hydrophilic coating band width A of at least 1.5 times the shear droop width X. This hydrophilic coating band comprises amphoteric surfactant(s) in an amount greater than all other surfactants. Such individual precursors are obtained by cutting a continuous radiation-sensitive web into strips and such cutting creates the shear droop that can result in edge staining if the hydrophilic coating band is not present.

A method of roughening a surface of a printing form precursor. The method comprises subjecting at least a part of the surface to energy in the form of pulses of electromagnetic radiation to produce a uniformly hydrophilic roughened surface on at least a part of the printing form precursor and optionally converting the uniformly hydrophilic roughened surface of the printing form precursor to a uniformly hydrophobic roughened surface. The method is useful for providing a surface for use in a subsequent imaging and/or printing process in lithographic printing. Methods of providing a printing form comprising an image formed of hydrophobic regions and hydrophilic regions using said method and a method of printing using said method are also described, as are printing forms so produced and imaging devices and apparatus for carrying out the said methods.

Flexographic printing members are prepared from a flexographic printing plate precursor consisting essentially of: backing film, water- or water-dispersible photosensitive layer, and cover sheet in contact with the photosensitive layer. The cover sheet is removed and a mask element is laminated directly in contact with the photosensitive layer. Exposure through the mask element provides exposed regions and non-exposed regions. The non-exposed regions are removed with an aqueous developer having: a) a C.sub.12-20 saturated or unsaturated fatty acid (or alkali metal salt) at 0.25-2.0 weight %, and at least 85 weight % of a C.sub.18 mono- or poly-unsaturated fatty acid (or alkali metal salt); b) an aminopolycarboxylic acid (or alkali metal salt) at 0.05-0.30 weight %; c) a buffer at 05-0.60 weight %; and d) water. The photosensitive layer has a controlled release of 5-500 g/cm using ASTM D-3330 Method D, between its front imaging surface and the mask element.

Provided is a printing plate precursor including: a support; a layer which contains a polymer on one side of the support; and a layer which contains a metal oxide obtained by hydrolyzing and polycondensing an organic metal compound or an inorganic metal compound and fine particles on the other side of the support, in which an average particle diameter of the fine particles is 0.3 m or greater and is greater than the thickness of the layer containing a metal oxide and fine particles, and in a case where the printing plate precursors are laminated, dislocation in stacking precursors, adhesion between precursors, and scratches can be all prevented even without using interleaving paper.

A lithographic printing sleeve for mounting on a cylinder in a printing press is provided. The lithographic printing sleeve includes a tubular base layer for contacting and surrounding an outer circumference of the cylinder, a permanent tubular hydrophilic layer on an outer surface of the tubular base layer and a temporary hydrophobic layer on an outer surface of the tubular hydrophilic layer. A variable cutoff printing press is also provided.

A photosensitive resin printing plate precursor is disclosed for relief printing, including a support, a photosensitive resin layer, and a cover film stacked in this order, wherein the photosensitive resin layer comprises a lower layer present on a support side and an upper layer present on a cover-film side, wherein the upper layer is a photosensitive resin layer that contains a water-soluble or water-dispersible resin (A) having a glass transition temperature measured by differential scanning calorimeter of 40 to 90 C., wherein the upper layer has a thickness of 3 to 30 micrometers, wherein the lower layer is a layer that contains a water-soluble or water-dispersible resin (B) having a glass transition temperature higher than the glass transition temperature of the water-soluble or water-dispersible resin (A) by 5 C. or more, and wherein the glass transition temperature of the resin (B) measured by differential scanning calorimeter is 95 to 135 C.

A method of forming printing sleeve for mounting on a cylinder in a printing press is provided. The method includes providing a permanent hydrophilic tubular layer on a tubular base; selectively providing a first temporary hydrophobic layer on the hydrophilic tubular layer to form a first imaged printing sleeve, the temporary hydrophobic layer forming a first image; printing, by the first imaged printing sleeve, a first print job including the first image on a substrate; and removing the first temporary hydrophobic layer from the permanent hydrophilic layer such that the permanent hydrophilic layer remains intact on the tubular base. A lithographic printing sleeve for a printing press is also provided.

An on-machine development type planographic printing plate precursor has a support and an image-recording layer on the support. The image-recording layer contains an initiator, an infrared absorber capable of donating electrons to the initiator, and a color-developing substance precursor. The image-recording layer can form an image by exposure to infrared laser, and in a case where the image-recording layer is exposed to an infrared laser with a wavelength of 830 nm at an energy density of 110 mJ/cm.sup.2, a brightness change L of the image-recording layer before and after the exposure is 3.0 or more. A method for preparing a planographic printing plate and a planographic printing method employ the on-machine development type planographic printing plate precursor.

An on-press development type lithographic printing plate precursor has a support, an image-recording layer, and an outermost layer in this order. The image-recording layer contains an infrared absorber, an electron-accepting polymerization initiator, and a polymerizable compound. LUMO of the electron-accepting polymerization initiator-LUMO of the infrared absorber is 0.45 eV or more, and the outermost layer contains a discoloring compound. A method of preparing a lithographic printing plate and a lithographic printing method employ the on-press development type lithographic printing plate precursor.

A method for manufacturing a lithographic printing plate precursor includes the steps of providing a support as a web, coating an image recording layer on the front side of the support, and depositing a back layer on the back side of the support using a deposition technique which is capable of depositing the back layer according to a predefined image. The method enables stacking and recutting of lithographic printing plate precursors without the need for interleafs.