| 摘要 |
A method for phase adjusting a plurality of printing units in a variable format printing press is provided which includes for each of the plurality of printing units (P1 to Pn), determine an angular position (MBPosx) of a motor shaft of the motor driving the blanket cylinder of the printing unit when a plate edge of a plate mounted on the plate cylinder of the printing unit is in a nip formed between the plate cylinder and blanket cylinder of the printing unit, and for each of the printing units P2 to Pn, phase adjusting MBPosx relative to MBPos1 so that when edge E1 reaches a nip between the blanket cylinder and impression cylinder of printing unit Px, edge Ex is printed on the web. The step of phase adjusting includes calculating a number of stretched images between Px and P1, as a function of a nominal repeat length, a substrate modulus of the web, a web tension, and a distance between printing unit Px and printing unit P1; and based on the calculating step, calculating an phase adjusted angular position PMBPosx of the motor shaft of the motor driving the blanket cylinder of the printing unit Px when the motor shaft of the motor driving the blanket cylinder of the printing unit P1 is MBPos1; and rotating the blanket cylinders to reflect these relative positions. |
| 主权项 |
1. A variable format printing press for printing on a web, comprising
a first printing unit including a first plate cylinder, a first blanket cylinder, and a first impression cylinder, a first motor including a first motor shaft for rotating at least the first blanket cylinder, and a first position sensor for sensing a position of the first motor shaft, the first plate cylinder and first blanket cylinder forming a first nip; a second printing unit downstream of the first printing unit, the second printing unit including a second plate cylinder, a second blanket cylinder, and a second impression cylinder, a second motor including a second motor shaft for rotating at least the second blanket cylinder, and a second position sensor for sensing a position of the second motor shaft, the second plate cylinder and second blanket cylinder forming a second nip; a third printing unit downstream of the second printing unit, the third printing unit including a third plate cylinder, a third blanket cylinder, and a third impression cylinder, a third motor including a third motor shaft for rotating at least the third blanket cylinder, and a third position sensor for sensing a position of the third motor shaft, the third plate cylinder and third blanket cylinder forming a third nip; a controller coupled to the first, second and third motors and to the first second and third position sensors, the controller including a memory, the memory having stored thereon information sufficient to determine a first angular position of the first motor shaft when a printing plate edge is in the first nip, a second angular position of the second motor shaft when a printing plate edge is in the second nip, and a third angular position of the third motor shaft when a printing plate edge is in the third nip, the controller controlling the motors to adjust a phase of the second and third motors relative to the first motor as a function of a nominal repeat length of a current format of the printing unit, a web tension of the web, a substrate modulus of the web, and a distance between the first nip and the second nip and a distance between the first nip and the third nip. |
