Coating device and image forming system

A coating device comprising:

• a reservoir to store a coating liquid;
• a coating roller to coat a sheet with the coating liquid supplied from the reservoir as a coating operation;
• a pressure roller to contact the coating roller to form a nip between the coating roller and the pressure roller to nip and convey the sheet;
• a separator to bring the pressure roller into contact with the coating roller and separate the pressure roller from the coating roller;
• a supply unit to supply the coating liquid to the reservoir;
• a drain unit to drain the coating liquid from the reservoir;
• a liquid level detector to detect that a liquid level of the coating liquid in the reservoir is below a non-supply position at which the coating liquid is not supplied to the coating roller;
• and
• circuitry configured to:
• control the drain unit to drain the coating liquid from the reservoir after the liquid level detector detects that the liquid level is below the non-supply position after a power-off of the coating device;
• control the separator to bring the pressure roller into contact with the coating roller to form the nip after a detection of the liquid level below the non-supply position by the liquid level detector;
• and
• rotate the pressure roller and the coating roller for a predetermined time while the pressure roller and the coating roller form the nip as an idle rotation.