Phase detection in an ink jet system printer of the charge amplitude controlling type

摘要

In an ink jet system printer of the charge amplitude controlling type, an electric current flows through an ink droplet issuance unit to ink liquid when an ink droplet is properly charged by charging means. A detection circuit is connected to the ink droplet issuance unit for detecting the electric current flowing through the ink droplet issuance unit, thereby developing a phase OK signal when a predetermined electric current is detected.