Abstract: In a printer including a platen rotatably provided around a first axis and a plurality of recording member pressing rollers rotatably provided around a second axis parallel with the first axis in which a recording member is forwarded to a printing position around the platen faced with a printing head and is pressed on the platen by the recording member pressing rollers, a recording member pressing device comprises a memory for storing positioning information of at least one of the pressing rollers depending on the size of the recording member, a recording member size detector for detecting the size of the inputted recording member, read-out means responsive to the recording member size detector for reading out the positioning information stored in the memory, and positioning means responsive to the read-out means for slidably moving the at least one of the pressing rollers along the second axis and setting the pressing position of the at least one of the pressing rollers.

Abstract: An electromagnetic cross valve is provided for selectively connecting a nozzle with an ink liquid supply conduit and an ink liquid drain conduit. When the nozzle is connected with the ink liquid drain conduit, ink liquid is maintained at the atmospheric pressure and remains in the nozzle in such a manner that the ink liquid is filled to the tip end of the nozzle or the orifice of the nozzle. Fluid resistance means are disposed between the electromagnetic cross valve and the ink liquid drain conduit for preventing generation of negative pressure at the nozzle side when the nozzle is connected with the ink liquid drain conduit.

Abstract: The inner surface of a charging tunnel for use in an ink jet system printer is tapped. Openings are provided at the bottom surface of the charging tunnel and porous material is provided in such a manner as to surround the charging tunnel.

Abstract: A plate shaped slim electrode is mounted on a carriage which supports an ink issuing unit and a charging tunnel, and is driven to travel in the lateral direction. A cylinder shaped rotary deflection electrode is rotatably mounted on the body of an ink jet system printer in a direction parallel to the travelling direction of the carriage. In a preferred form, a slit opening is formed in the center of the plate shaped slim electrode. The plate shaped slim electrode is maintained at the ground potential, whereas the rotary deflection electrode is connected to a high voltage source to establish a high voltage electric field between the plate shaped slim electrode and the rotary deflection electrode.