Abstract: In a printing press, ink fountain keys are disposed to be movable toward and away from an ink fountain roller of an ink fountain to allow them to have a predetermined gap therebetween and hence the amount of ink to be fed to a downstream roller to be determined. The ink fountain roller is rotated while ink is prevented from being fed to the downstream roller. At least one of the ink fountain keys is moved so as to allow the at least one of the fountain keys to change a position thereof relative to the ink fountain roller of the ink fountain with time. With this arrangement, it is possible to improve an ink kneading effect produced by the rotation of the ink fountain roller without the necessity to manually knead ink in the ink fountain by the operator and the necessity to provide any ink kneading device or unit independently of the printing press.

Abstract: A method of controlling an ink transfer roller is provided. This method achieves stabilized printing quality by evenly distributing ink transfer actions of the ink transfer roller for the number of rotation of a plate cylinder. The ink transfer action of an ink transfer roller is controlled based on the fact whether a value obtained by setting the value of C after calculation as a hysteresis value and adding the number ratio thereto exceeds a predetermined basic value or not, thereby allowing the ink transfer roller to perform ink transfer actions evenly at the number ratio set by an operator. With this method, unevenness in printing quality can be prevented.

Abstract: A method of controlling an ink transfer roller is provided. This method achieves stabilized printing quality by evenly distributing ink transfer actions of the ink transfer roller for the number of rotation of a plate cylinder. The ink transfer action of an ink transfer roller is controlled based on the fact whether a value obtained by setting the value of C after calculation as a hysteresis value and adding the number ratio thereto exceeds a predetermined basic value or not, thereby allowing the ink transfer roller to perform ink transfer actions evenly at the number ratio set by an operator. With this method, unevenness in printing quality can be prevented.

Abstract: In a printing press, ink fountain keys are disposed to be movable toward and away from an ink fountain roller of an ink fountain to allow them to have a predetermined gap therebetween and hence the amount of ink to be fed to a downstream roller to be determined. The ink fountain roller is rotated while ink is prevented from being fed to the downstream roller. At least one of the ink fountain keys is moved so as to allow the at least one of the fountain keys to change a position thereof relative to the ink fountain roller of the ink fountain with time. With this arrangement, it is possible to improve an ink kneading effect produced by the rotation of the ink fountain roller without the necessity to manually knead ink in the ink fountain by the operator and the necessity to provide any ink kneading device or unit independently of the printing press.

Abstract: A printing unit of a sheet-fed printing press for printing on sheets includes a plate cylinder having a circumference, on which a recess is formed; a feed reel mounted within the recess for feeding a printing film onto the circumference of the plate cylinder so as to introduce an image forming region for each printing operation; an image forming device for forming an image on the image forming region of the printing film fed on the circumference of the plate cylinder with the first edge of the image forming region positioned at an edge of the recess closer to the rewind reel; a rewind reel mounted within the recess for rewinding the printing film from the circumference of the plate cylinder; and a control unit for controlling the length of the printing film to be fed from the feed reel onto the circumference of the plate cylinder, based upon the length of sheets to be printed for each printing operation.

Abstract: A printing unit of a sheet-fed printing press for printing on sheets includes a plate cylinder having a circumference, on which a recess is formed; a feed reel mounted within the recess for feeding a printing film onto the circumference of the plate cylinder so as to introduce an image forming region for each printing operation; an image forming device for forming an image on the image forming region of the printing film fed on the circumference of the plate cylinder with the first edge of the image forming region positioned at an edge of the recess closer to the rewind reel; a rewind reel mounted within the recess for rewinding the printing film from the circumference of the plate cylinder; and a control unit for controlling the length of the printing film to be fed from the feed reel onto the circumference of the plate cylinder, based upon the length of sheets to be printed for each printing operation.