Abstract:
A device as well as method for treating without developing an imagewise exposed lithographic printing plate is disclosed. The device comprises a structure for providing a treating solution to the exposed plate. The exposed plate comprises on a substrate a photosensitive layer having hardened areas and non-hardened areas (for negative plate) or solubilized areas and non-solubilized areas (for positive plate). The non-hardened or solubilized areas of said photosensitive layer is removable with ink and/or fountain solution on a lithographic press. The treatment of the imagewise exposed plate allows one or more enhanced properties for the plate before on-press development, such as improved white light stability, enhanced or formation of visible image, improved hydrophilicity, or improved on-press developability.
Abstract:
A method of developing a laser sensitive lithographic printing plate with ink and/or fountain solution is described. The printing member comprises on a substrate a photosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser. The plate is exposed with a laser, deactivated, and then on-press developed with ink and/or fountain solution. Alternatively, the plate is developed with ink and/or fountain solution or the like off press, and then mounted on press for lithographic printing. The deactivation or off-press development allows the plate to be handled on press under white light or other light which is unsafe for a non-deactivated plate.
Abstract:
A method of deactivating and on-press developing an exposed lithographic printing plate is disclosed. The plate comprises on a substrate a photosensitive layer developable with ink and/or fountain solution and capable of hardening upon exposure to a radiation. The plate is exposed with the radiation, deactivated, and then on-press developed with ink and/or fountain solution. The deactivation of the exposed plate allows the handling of the plate under regular office light or any other light without causing the hardening of the non-exposed areas of the photosensitive layer.
Abstract:
A method of on-press developing a high-speed laser sensitive lithographic printing plate with ink and/or fountain solution is described. The printing member comprises on a substrate a photosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser. The plate is exposed with a laser and on-press developed with ink and/or fountain solution. The on-press development is performed with the plate under a yellow-red light or in substantial darkness, and the lithographic printing is performed under white light.
Abstract:
An on-press ink and/or fountain solution developable lithographic printing plate comprising a photosensitive layer over an electrochemically grained, anodized, hydrophilically treated aluminum substrate with a reflection optical density of at least 0.30 is disclosed. The photosensitive layer is soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser having a wavelength of from 200 to 1200 nm. The plate is exposed with the laser off press or on press, and then on-press developed with ink and/or fountain solution. Such darker aluminum substrate in combination with the hydrophilic treatment allows fast press roll up, clean background, and good printing durability of the plate.
Abstract:
A method of on-press developing a thermosensitive lithographic printing plate with ink and/or fountain solution is described. The lithographic plate comprises on a substrate a thermosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to an infrared radiation. The printing plate can be a pre-coated plate in the form of sheet or web, or can be prepared on press by coating a thermosensitive layer onto a substrate that is a sheet material or a seamless sleeve mounted on a plate cylinder or is the surface of a plate cylinder of the lithographic press.
Abstract:
A method of on-press developing a laser sensitive lithographic printing plate with ink and/or fountain solution is described. The printing member comprises on a substrate a photosensitive layer soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to a laser. The plate is exposed with a laser and on-press developed with ink and/or fountain solution. The exposure and development are performed with the plate under lightings that contain no or substantially no radiation below a wavelength selected from 400 to 650 nm, or in the dark or substantially dark.