Printer

Claim 1

A printer comprising: a sheet advancing roller having wound around it a first printing sheet with perforations or a second printing sheet without perforations and adapted, upon rotation, for advancing the printing sheet of either type; advancing means, provided with a plurality of pins around the periphery thereof, for advancing the first printing sheet to said sheet advancing roller upon rotation when the perforations of the first printing sheet are fitted on the pins, said advancing means effecting sheet advancing upon rotation of said sheet advancing roller; holding means for holding said printing sheet to said advancing means so as to maintain the perforations of the first printing sheet on the pins of said advancing means; means for manually rotating said sheet advancing roller; first and second movable pressure rollers which can be maintained in contact with or separated from said sheet advancing roller, said first movable pressure roller being located nearer said advancing means than said second movable pressure roller; and operating lever means comprising a movable lever and a link attached to said lever for contacting or separating said first and second movable pressure rollers with or from said sheet advancing roller, said link having first and second opposite ends, the first end of said link being pivotally connected to said lever, the second end of said link being formed with a hook, said first movable pressure roller having an axle which engages a slot in a central portion of said link, said movable lever having a first position wherein said first and second movable pressure rollers are in contact with said sheet advancing roller, a second position wherein said first movable pressure roller is in contact with said sheet advancing roller and said second movable pressure roller is separated from said sheet advancing roller by said link and a third position wherein said first movable pressure roller is separated from said sheet advancing roller by said link and said second movable pressure roller is in contact with said sheet advancing roller, in said second position the hook of said link engaging a projection on an arm mounting said second movable pressure roller so as to cause said arm to pivot, thus releasing the second movable pressure roller from said sheet advancing roller, in said third position said link causing the axle of the first movable pressure roller translate, thus causing the first movable pressure roller to be released from said sheet advancing roller, also in the third position said hook becoming disengaged from the projection of the arm allowing the second movable pressure roller to remain engaged with the sheet advancing roller, said movable lever being maintained in a positive detent location in said first position, said second position and said third position.