A roller to contact an oscillating ink transfer drum in an inking system for a printing machineis disclosed. Itcomprisesa cylindrical body having a longitudinal axis and a curved outer surface. A recess is formed in the curved outer surface at an end of the cylindrical bodythatextendsaxially inward from said end of the cylindrical body by a depth that gradually reduces in a circumferential direction extending around said axis.
A method of removing a printing plate, each having leading and trailing edges located in respective lock-up slots in a plate cylinder of a printing press, from said plate cylinder, is disclosed. The method comprises the steps of extracting a first of said leading and trailing edges, rotating the plate cylinder in a first direction such that an extraction element located proximal to the surface of the plate cylinder passes beneath the extracted first edge until the printing plate is lifted off the surface of the plate cylinder by the extraction element, with the second edge still in its lock-up slot, to cause the second edge to move within its lock-up slot as the plate is lifted to loosen said second edge within its lock-up slot, rotating the plate cylinder in a second direction so that said plate drops back and, rotating the plate cylinder in the first direction again so that the extraction element pulls said loosened second edge out of said lock-up slot.
A method of releasing a seal formed between a used printing plate and a surface of a plate cylinder of a printing press prior to removal of said printing plate from said surface is disclosed. The method includes the step of directing a jet of compressed air towards the surface of the plate cylinder between adjacent printing plates.
A method of further inserting a partially inserted leading and/or trailing edge (8a, 8b) of a printing plate (8) into respective lock-up slots (9, 10) in a plate cylinder (2) of a printing press (1) to allow register slots in said edges to engage with lateral pins or a register mechanism in said lock-up slots is disclosed. The method comprises the step of positioning a pushing element (13) relative to the curved surface of the plate cylinder (2), on which a printing plate (8) is disposed with its leading and/or trailing edges (8a, 8b) partially inserted into their respective lock-up slots (9, 10), such that said pushing element (13) will engage and push a raised portion of said printing plate (8), adjacent to said partially inserted leading and/or trailing edge (8a, 8b), down onto the surface of the plate cylinder (2) and the leading and/or trailing edge (8a, 8b) further into their respective lock-up slots, as said plate cylinder (2) rotates.
Apparatus for detecting the presence of a partially loaded printing plate in individual printing plate mounting positions on a plate cylinder (2) of a printing press is disclosed. The system includes a discrete vacuum circuit associated with each individual printing plate mounting position. Each vacuum circuit includes suction elements (6) positionably spaced from the surface (2a) of a plate cylinder (2) so that, when a leading edge (7a) of a printing plate (7) has been received in a lock-up slot (10a) in a plate cylinder which is rotated to partially wrap said printing plate around said plate cylinder, a trailing edge (7b) portion of a printing plate is deflected away from the surface of the plate cylinder, due to its resilience, against the suction elements. It is thereby possible to generate a negative pressure in the vacuum circuit closed by said trailing edge portion of the printing plate against the suction elements. The existence of a negative pressure is used to indicate the presence' or absence of a partially loaded printing plate in each of the printing plate mounting positions.
A printing press (12) is disclosed. It comprises a print unit (13) and a slitting mechanism (16) associated with the print unit for slitting a web of print medium into a plurality of longitudinal ribbons as the web leaves the print unit. The printing press also comprising a folder (18) spaced from the print unit to receive ribbons cut by the slitting mechanism at the print unit. It also includes means for guiding a web of print medium through the print unit during a web-up procedure prior to initiation of a print run. The guide means is operable to separately guide each ribbon from the print unit to the folder as well as guiding the web through the print unit.
A method of controlling a printing unit is disclosed. The printing unit comprising a plurality of printing couple pairs, each printing couple pair comprising a plate cylinder and a blanket cylinder and an inking system associated with each printing couple pair operable to supply ink to printing plates mounted on the plate cylinders of said printing couple pairs. The printing unit also comprises a primary module carrying the printing couple pairs and, a pair of secondary modules carrying the inking systems, the secondary modules being movable relative to the primary module from an operative into a non- operative position in which each secondary module is separated from the primary module. The printing unit further comprises apparatus for loading/unloading printing plates from the plate cylinders of the printing unit and the method includes the step of unloading printing plates from the plate cylinders of the printing unit using said apparatus whilst the secondary modules are moving relative to the primary modules into their non-operative positions.
Apparatus for removing printing plates (8) having leading and trailing edges located in a lock-up slot in a plate cylinder (2) of a rotary printing press, from said plate cylinder (2) is disclosed. The apparatus comprises means for extracting the trailing edge from a lock-up slot which is also operable to partially extract the leading edge from a lock up slot. The apparatus further includes an extraction member for engaging, as the printing cylinder rotates, a portion of the leading edge (8a) of the printing plate protruding from the lock up slot (9) following its partial extraction, to complete the removal of the printing plates from the printing cylinder and leave the removed plates, hanging by their leading edge (8a), on the extraction member. A method of loading printing plates onto a plate cylinder (2) is also disclosed.
A rotary printing press is disclosed. It comprises a print unit for applying ink to a web of print medium (7) passing through the unit, a folder located adjacent to the print unit to receive the printed web from the print unit and, a slitting mechanism (2) located between the print unit and the folder to longitudinally slit the web into a plurality of ribbons (8a, 8b) each travelling side-by-side across the width of the press for entry into the folder. The press includes means (9,10) for changing the position of at least one ribbon (8a) relative to the or each adjacent ribbon (8b) so that the edges of adjacent ribbons are spaced apart from each other in a direction across the width of the press before entering the folder.
Apparatus for dampening a printing press comprises a spray bar (26) with solenoid operated nozzles (29) for dispensing a dampening fluid to the press, a controller (30) that sets the flow rate of the dampening fluid to the press through the nozzles, and workstation (31) operable to drive the controller (30). The nozzles (29) are to set an initial flow rate for the commencement of a print run, corresponding to an initial setting value (IS) dependent on a default value (D) and a stored value (AVOFS) derived during at least one preceding print run, and then the setting is updated during the print run by updated data (AS) corresponding to an updated flow rate for the commenced print run. An offset value (OFS) is then calculated based on the difference between (IS) and (AS). The stored value (AVOFS) is then calculated based on a running average of (OFS) for successive print runs.
A printing plate module is disclosed. The module comprises a printing plate support member (3) having means (5) to locate printing plates (4) in a predetermined position thereon and, engagement means (8) on the plate support member for the releasab a engagement of the printing plate support member (3) with a printing press during a plate loading operation to locate printing plates (4) located on the plate support member (3) in a predetermined position relative to a plate cylinder (7) of the press. The invention also discloses a printing apparatus and, a method of loading printing plates onto a plate cylinder of a printing unit.