摘要:
An apparatus for driving a pair of nip rollers at a rotational velocity that varies within each revolution is provided. A first nip roller and a second nip roller form a nip therebetween for moving a sheet or signature. A drive configured and arranged to drive a drive shaft at a constant rotational speed. A pair of variable rotational speed couplings each have an input coupled to the drive, and an output connected to a respective one of the first and second nip rollers. Each coupling rotates its respective nip roller at a rotational speed that varies within each revolution.
摘要:
An apparatus for driving a pair of nip rollers at a rotational velocity that varies within each revolution is provided. A first nip roller and a second nip roller form a nip therebetween for moving a sheet or signature. A drive configured and arranged to drive a drive shaft at a constant rotational speed. A pair of variable rotational speed couplings each have an input coupled to the drive, and an output connected to a respective one of the first and second nip rollers. Each coupling rotates its respective nip roller at a rotational speed that varies within each revolution.
摘要:
A printing press is provided. The printing press includes a print unit printing a stream of printed products having a first pitch, a pitch changing device and a controller. The pitch changing device includes an upper roller mounted on an upper axle, a lower roller mounted on a lower axle, the upper and lower rollers forming a roller nip and at least one motor driving the upper and lower rollers in opposite directions. The roller nip receives the stream of printed products. The controller is connected to the at least one motor and is configured to decrease an initial velocity of the roller nip to a final velocity using an electronic cam velocity profile and to increase the final velocity of the nip to the initial velocity after releasing the printed products over a longer period of a cycle of the electronic cam velocity profile than decreasing the initial velocity to the final velocity. A method is also provided.
摘要:
A printing press is provided. The printing press includes a print unit printing a stream of printed products having a first pitch, a pitch changing device and a controller. The pitch changing device includes an upper roller mounted on an upper axle, a lower roller mounted on a lower axle, the upper and lower rollers forming a roller nip and at least one motor driving the upper and lower rollers in opposite directions. The roller nip receives the stream of printed products. The controller is connected to the at least one motor and is configured to decrease an initial velocity of the roller nip to a final velocity using an electronic cam velocity profile and to increase the final velocity of the nip to the initial velocity after releasing the printed products over a longer period of a cycle of the electronic cam velocity profile than decreasing the initial velocity to the final velocity. A method is also provided.