The present invention provides an optical communication system, which comprises photodetection means for receiving communication light and optical means for forming an image from the communication light on the photodetection means, wherein the optical means is provided with a diffraction optical member having at least 0-th diffraction order. When an overwrite command is received while executing the mixed operations, which writes to a predetermined tape position, when a tape position to overwrite on is encountered before the append-written data ending position of the tape, the overwritten tape position is regarded as the append-written data ending position of the tape to update the tape EOD by the overwritten tape position. Another user can log in using one or more communication devices. A deformably resilient material surrounds the socket, permitting the upright member to deflect slightly and return to a substantially perpendicular orientation relative to the base. This eliminates the release oil from building up on the fuser roller and transferring to subsequent larger receiver sheets, and reduces non-uniform wear on rollers at the fuser, thus reducing likelihood of image artifacts and machine contamination.