Abstract: Disclosed is an ink jet printing process comprising: filtering an oil-based ink; forming an image directly on a printing medium by an ink jet method comprising ejecting said filtered oil-based ink using electrostatic field based on signals of image data; and fixing said formed image to obtain a printed matter. Also disclosed is a printing apparatus suitable for the process.

Abstract: A method of making a printing plate comprising forming an image on a surface of a first image-holding body based on image data signals by an electrostatic inkjet process comprising ejecting an oil-based ink; and contact-transferring the image formed on said first image-holding body onto a second image-holding body. Also disclosed are plate making apparatuses suitable for the method.

Abstract: An ink jet printing method which comprises: directly forming an image on a printing medium on the basis of signals of image data; and fixing the image to produce a printed matter, wherein said image formation is carried out by an ink jet system of ejecting an oily ink by an electrostatic field. The method preferably further comprises cleaning an ink jet head, said cleaning step comprising: immersing said ink jet head in a cleaning solution; and applying voltage to said ink jet head. Alternatively, the method preferably further comprises, when a malfunction happens, either or both of stopping the image formation and eliminating a cause of the malfunction. Also disclosed are printing apparatuses suitably used for these methods.

Abstract: A method of computer-to-cylinder type lithographic printing comprising: loading a plate material on a plate cylinder of a printing apparatus; forming an image, based on image data signal, directly onto the plate material by an inkjet image-recording process comprising ejecting an oil-based ink from a recording head; heat-fixing the thus formed inkjet image to prepare a printing plate; and performing lithographic printing with the thus prepared printing plate, wherein said heat fixing step comprises heating with a heat roller. In a preferred embodiment, said heat-fixing step further comprises preliminary heating prior to said heating with the heat roller. Also disclosed are computer-to-cylinder type lithographic printing apparatuses for carrying out the printing methods.