Patent ID: 7754116

Claim:
A sheet forming apparatus, having two rollers placed in parallel at a distance and forming a sheet by passing the sheet between the two rollers rotatively driven with both surfaces of the sheet contacting the two rollers, the sheet forming apparatus comprising: a roller gap adjustment unit adjusting a roller gap by moving at least one of the two rollers; and a roller gap control unit with two control modes: a constant roller gap control mode where the roller gap adjustment unit adjusts the roller gap between the two rollers so that the roller gap between the two rollers converges to a predetermined control target value; and a constant pressing load control mode where the roller gap adjustment unit adjusts a value of the roller gap between the two rollers so that a pressing load acting on the roller converges to a predetermined control target value, the roller gap control unit controlling the roller gap by selectively running either one of the two modes, wherein when switching the control mode from the constant pressing load control mode to the constant roller gap control mode, the roller gap control unit sets as a control target value of roller gap one of a roller gap measured immediately before the mode switch and an average of the roller gap measured during a predetermined time, and when switching the control mode from the constant roller gap control mode to the constant pressing load control mode, the roller gap control unit sets as a control target value of pressing load one of a pressing load measured immediately before the mode switch and an average of pressing load measured during a predetermined time.