Patent ID: 7770538

Claim:
A coating machine for applying a coating to printed sheets, comprising: a coating cylinder having an image area thereon; an impression cylinder disposed opposite the coating cylinder for defining therewith a coating nip; a transport mechanism for advancing printed sheets successively through the coating nip; a drive mechanism for driving the transport mechanism synchronously with the coating cylinder and the impression cylinder; a feeding mechanism for feeding printed sheets from an inlet to the coating nip, comprising: driven rollers spaced apart along a direction of sheet feed for feeding sheets toward the coating nip, the spaced apart driven rollers being driven independently of one another by respective motors, and a first sensor for sensing the arrival of successive printed sheets and providing therefrom respective initial sheet position signals, and a second sensor spaced downstream from the first sensor and upstream from the coating nip, for sensing successive sheets being fed and providing therefrom respective updated sheet position signals; and a control unit connected to the independently driven motors, the first and second sensors, and the drive mechanism of the transport mechanism, for receiving the initial and updated sheet position signals to determine therefrom initial and updated speeds for feeding the individual sheets in order for each sheet to arrive at the coating nip synchronously with both the transport mechanism and the image area of the coating cylinder and at a speed substantially equal to a surface speed of the coating cylinder, and for independently driving the motors for feeding each sheet at its respective initial and updated speeds.