Patent ID: 6302018
Filing Date: 2001-10-16
Classification: B41F,B41P

Abstract:
An offset printer comprising:a frame;a drive motor supported on the frame;a drive gear for outputting a rotation force of the drive motoran impression cylinder having an impression cylinder gear provided coaxially and integrally rotatable therewith, the impression cylinder gear being meshedly engaged with the drive gear for rotating the impression cylinder upon rotation of the drive gear;a paper feed mechanism comprising a paper feed cylinder gear meshedly engaged with the impression cylinder gear, and a paper feed cylinder rotatable coaxially with the paper feed cylinder gear upon rotation of the impression cylinder gear for feeding a paper to a surface of the impression cylinder;a paper discharge mechanism comprising a paper discharge gear meshedly engaged with the impression cylinder gear, a paper discharge portion rotatable coaxially with the paper discharge gear, and an endless chain mounted on the paper discharge portion and circularly movable on the paper discharge portion for removing the paper from the impression cylinder;a blanket cylinder in contact with the surface of the impression cylinder and having a blanket cylinder gear meshedly engaged with the impression cylinder gear, the blanket cylinder gear being rotatable integrally with the blanket cylinder upon rotation of the impression cylinder gear;a plate cylinder having a plate cylinder gear meshedly engaged with the blanket cylinder gear, the plate cylinder being rotatable integrally and coaxially with the plate cylinder gear upon rotation of the blanket cylinder gear and in contact with a surface of the blanket cylinder for forming an image on a surface of the plate cylinder;an ink supplying mechanism driven by the rotation of the plate cylinder for supplying an ink to the surface of the plate cylinder, an inked image being formed on the surface of the plate cylinder by the supplied ink based on an image formed on the surface of the plate cylinder, and the inked image on the plate cylinder being transferred to the surface of the blanket cylinder, and the impression cylinder pressing a paper against the surface of the blanket cylinder for transferring the inked image on the blanket cylinder to the paper; anda power transmission shut off mechanism for preventing the rotation force of the drive motor from being transmitted to at least one of the paper feed mechanism, the paper discharge mechanism and the ink supplying mechanism at least during image formation process on the surface of the plate cylinder.