| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem in an inkjet head that an image quality degrades as a nozzle clogs due to an increase of an ink viscosity in the nozzle when a downtime of printing becomes longer, or ink droplets are not normally ejected depending on a length of the printing downtime even if the downtime does not result in clogging. <P>SOLUTION: The inkjet apparatus has a calculation means which obtains a pressure of the ink nozzle by a preliminarily established calculation expression on the basis of a pressure detected from an ink tank of an ink circulation system and connected to the inkjet head. A value Y obtained by the calculation means is compared with a reference value Pn at a pressure determination means, and determined whether to be a positive pressure or a negative pressure relative to the reference value. A pump is connected to the ink circulation system. When it is determined to be the positive pressure relative to the reference value Pn, a negative pressure value to the ink nozzle is raised. The pressure determination means can change the reference value Pn to the negative pressure side, whereby the viscosity-increased ink or the like is removed from the nozzle. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
