Patent ID: 8325376

Claim:
An image-forming device comprising: a processor; a memory having machine readable instructions stored thereon that, when executed by the processor, perform steps including performing a conversion process to convert a plurality of sets of print data, which are of differing formats from one another, into intermediate data of a common format, the conversion process converting each set of print data into a corresponding set of intermediate data; creating page data from the intermediate data in parallel with the conversion process; causing a printing unit to perform an index printing operation based on page data created by the creating step; storing in a storing unit at least one page data creatable range delimiter for the intermediate data by which the creating step creates the page data from the intermediate data, the one page data creatable range delimiter being stored in the storing unit after the conversion process converts at least a part of one set of print data of one format into a set of intermediate data, from which page data is creatable; performing a replacement process to replace at least the intermediate data Positioned after the page data creatable range delimiter in the print data with substitute data when an error occurs in the print data during the conversion process; and updating the current page data creatable range delimiter to the next page data creatable range delimiter after the conversion process has converted the print data to intermediate data up to the next page data creatable range delimiter; wherein the storing step includes storing each of the plurality of page data creatable range delimiters while the page data creatable range delimiters are sequentially updated; the creating step includes sequentially creating the page data based on the plurality of page data creatable range delimiters and storing the page data creatable range delimiter corresponding to the created page data in the storing unit as a data creation progress delimiter; and the replacing step includes replacing with the substitute data the intermediate data following the page data creatable range delimiter that is stored immediately after the page data creatable range delimiter that corresponds to the data creation progress delimiter.