In an inkjet printer, a cap part for receiving ink from a head unit during maintenance includes a liquid receiving part and an exhaust part disposed laterally to the liquid receiving part. A second different insulative material is deposited. A plurality of spaced apart spring retainers are disposed within the cylindrical housing with electrically conductive coil spring contacts therein. The piston unit has two channels, allowing air to flow into the valve chamber, passing two sides of the piston unit. The output current is determined by taking the difference between the first and second measured-value signals FIG. This allows the webbing section to be trapped between two bars, one sliding and one fixed.