Image forming system including sheet laminator and method of controlling power consumption

An image forming method comprising:

• printing an image on a sheet;
• calculating a power consumed by an image forming apparatus during a first start-up period and a power consumed by a sheet laminator during a second start-up period;
• controlling a timing based on the calculation result of a later one of the first start-up period or the second start-up period and controlling, based on the calculation result, a power supply during the later one of the first start-up period or the second start-up period;
• performing a lamination processing on a two-ply sheet with the sheet, which is inserted between two sheets of the two-ply sheet;
• performing a lamination print mode to perform the lamination processing on the sheet printed and conveyed;
• and
• performing a shift mode to:
• start the power supply to the printing and control an end of the power supply when the power supply reaches a first peak value and is stabilized during the first start-up period;
• and
• start the power supply to the lamination processing and control an end of the power supply when the power supply reaches a second peak value and is stabilized during the second start-up period shifted from the first start-up period.

An image forming system comprising:

• an image forming apparatus to print an image on a sheet, the image forming apparatus including a fixing device;
• a sheet laminator including a heater to perform a lamination processing on a two-ply sheet with the sheet, which is conveyed from the image forming apparatus and inserted between two sheets of the two-ply sheet;
• and
• circuitry to:
• perform a lamination print mode to cause the sheet laminator to perform the lamination processing on the sheet printed and conveyed from the image forming apparatus;
• and
• perform a shift mode to:
• start a power supply to the fixing device and control an end of the power supply when the power supply reaches a first peak value and is stabilized during a first start-up period;
• and
• start the power supply to the sheet laminator and control an end of the power supply when the power supply reaches a second peak value and is stabilized during a second start-up period shifted from the first start-up period.