PRINTING SYSTEM

PURPOSE:To ensure that data is printed even if a sheet is not of an appropriate size by indicating a message for warning a user and a message for selecting between the continuation of and the ending of printing, if the sheet is of a different size, and issuing a mandatory printing command if the printing is continued and permitting the printing to be performed by a mandatory printing command execution device. CONSTITUTION:A main system processing device 5 compares the size of a sheet for a document to be printed with the size of a sheet sent from a printing device 2. If the size of a sheet is different, a selected image display device 15 indicates a message for warning a user and a message for selecting between the continuation of and the ending of printing using a display device 8. When the continued printing is selected, a mandatory printing command is sent to the printing device 2 from a mandatory printing command sending device 17, and the printing device 2 is set to the mandatory printing mode using a mandatory printing execution device 18, if the size of a sheet for a document to be printed differs from that to be set to a printing part 12. After that, documentary data to be sent from a host computer 1 is processed for printing.