An image forming apparatus includes a hand detection sensor that detects a hand within a predetermined range from a grasping part of a sheet feeding cassette, a locking mechanism capable of locking the sheet feeding cassette in a closed state with respect to the image forming apparatus body, and an operation control unit that operates the locking mechanism to lock the sheet feeding cassette when the hand is detected by the hand detection sensor during the execution of a printing process in an image forming apparatus body, interrupts the printing process after the locking, and releases the locking by the locking mechanism after the interruption.

A method for printing digital images on at least one input roll of media in order to form at least one output roll by means of a roll-to-roll printing system is disclosed. The roll-to-roll printing system includes a digital image queue including an entry for each digital image to be printed. The method includes registering in an entry of the digital image queue a first digital item identifying the digital image and digital items of print properties of the digital image, printing the digital image according to the order of the entry in the digital image queue, and registering in the entry a second digital item identifying an input roll on which the digital image is going to be printed and a third digital item identifying an output roll on which the printed digital image is going to be wound. A roll-to-roll printing system is configured to apply the method.