Patent ID: 9415959
Filing Date: 2016-08-16
CPC Classification: B65H,G03G

Claim Text:
1. An image forming apparatus comprising: a plurality of paper feeding cassettes that accommodate paper; a conveyance path for paper drawn out from each of the paper feeding cassettes; a common conveyance path that is provided in common to each of the paper feeding cassettes and includes a conveying roller conveying the paper conveyed from the conveyance path of each of the paper feeding cassettes; a branch part that switches between each of the conveyance paths drawn out from each of the paper feeding cassettes; a double feeding detection sensor, a paper thickness detection sensor, and a glossiness detection sensor that are provided at the common conveyance path on a downstream side of the branch part in a direction of conveyance for printing, from an upstream side to the downstream side in the direction of conveyance for printing in this order; a paper type detection unit that detects a type of the paper during printing with the paper thickness detection sensor and the glossiness detection sensor, when the double feeding detection sensor detects that there is no double feeding of the paper having passed through the common conveyance path; a paper type determination unit that determines whether there is a change in the type of the paper during the printing; a paper search unit that searches for whether there is an appropriate paper feeding cassette that accommodates paper having a paper type equal to the type of paper before the paper type is changed when there is a change in the type of the paper during the printing as a result of the determination; and a paper change unit that executes predetermined processing to the paper with the changed paper type and resumes conveyance of paper from the existing appropriate paper feeding cassette when there is the appropriate paper feeding cassette as a result of the search, wherein the paper change unit executes processing of returning the paper with the changed type to its original paper feeding cassette via the conveyance path leading to the paper feeding cassette by starting to operate the branch part and reversely rotating the conveying roller such that the paper with the changed type is reversely conveyed as the predetermined processing.