公开(公告)号：US20210023836A1

公开(公告)日：2021-01-28

申请号：US16933029

申请日：2020-07-20

Applicant: Semes Co., Ltd.

Inventor： Chulwoo KIM ,  Sanghwa LEE ,  Beomjeong OH

IPC: B41J2/045

Abstract: In a printing method using an ink jet head, a chemical liquid may be discharged onto a substrate from a plurality of nozzles of the ink jet head. Discharging numbers of the chemical liquid from the plurality of nozzles may be identified and a cumulative discharging number of the chemical liquid from the plurality of nozzles may be calculated. The cumulative discharging number of the chemical liquid may be compared with a previously set limit discharging number of the ink jet head. A replacement time of the ink jet head may be determined if the cumulative discharging number of the chemical liquid exceeds the previously set limit discharging number.