1. Field of the Invention
The present invention relates to a sheet supply apparatus for supplying a continuous sheet and to a printing apparatus.
2. Description of the Related Art
There is a printer known to print on a continuous sheet in a roll form (roll sheet) through an inkjet method. When having mounted a new roll sheet on a printer, a user would input the type of the roll sheet from an operating unit of the printer to associate the roll sheet with its type. The type of the roll sheet that has been input is used for succeeding image forming and convey controlling. When the roll sheet is removed from a mounting unit of the printer, a pattern (hereinafter referred to as barcode), which identifies the type of the sheet, is printed on the roll sheet at an end of the sheet (at the leading edge thereof) in order to retain the association between the roll sheet and its type. When the roll sheet with the barcode printed thereon is mounted on the mounting unit of the printer, the printer reads the barcode to set the type of the sheet automatically, eliminating a demand for the user to input the type of the roll sheet again.
A printer, disclosed in Japanese Patent Application Laid-Open No. 2010-264672, allows for replacing of a roll sheet unused for printing during the printing. When a roll sheet used for the printing is consumed, a replacement roll sheet is fed so that its barcode is read. If the type of the replacement roll sheet agrees with the type of the roll sheet used for the printing, the printing is continued. If the type of the replacement roll sheet disagrees with the type of the roll sheet used for the printing, the printing is suspended and an error is displayed.
The printer, described in Japanese Patent Application Laid-Open No. 2010-264672, allows a roll sheet to be mounted while another roll sheet is being printed. If, however, the type of the mounted roll sheet disagrees with the type of the roll sheet being printed, the printing operation is interrupted until the user mounts a roll sheet of the correct type.
If the mounted roll sheet lacks a barcode, or if its barcode is unreadable due to a stain or the like, it is problematic in that the type of the mounted roll sheet cannot be identified unless the user manually inputs information of the paper type. Furthermore, it is unknown whether or not the reading operation on the barcode of the mounted roll sheet has been executed until the roll sheet being printed is consumed and then the reading operation is attempted on the barcode. This leaves the printer unable to identify the type of the roll sheet if the user is away from the printer.