An image forming apparatus includes an image forming device; a fixing device; a first conveyance passage downstream from the fixing device in a sheet conveyance direction; a second conveyance passage downstream from the fixing device and communicating with the first conveyance passage; a sheet reversing member to reverse a conveyance direction of the sheet to the second conveyance passage; a divider to switch a route of the sheet between the first conveyance passage and the second conveyance passage; and a sheet detection sensor disposed downstream from the fixing device and upstream from the divider. The first conveyance passage includes a sheet outlet from which the sheet is ejected outside the apparatus. The apparatus further includes a ventilation passage communicating with an outside, to guide air from the outside to pass the sheet detection sensor and enter at least one of the first conveyance passage and the second conveyance passage.

The image forming apparatus includes a paper feed unit that stores print paper used for printing, a paper size sensor that detects a paper size of the print paper stored in the paper feed unit, a filter information setting unit that sets filter information indicating the paper size detected by the paper size sensor in association with the paper feed unit, and a paper catalog list generating unit that extracts a paper catalog matching the filter information from paper catalogs included in predetermined paper catalog data and generates a paper catalog list using the extracted paper catalog.

A control unit of the invention compares printing setting suitable for a determined type of a recording material and printing setting of the recording material input by a user, and in a case where a difference between the printing setting suitable for the determined type of the recording material and the printing setting of the recording material input by the user falls in a predetermined range, the control unit performs a printing operation in accordance with the printing setting of the recording material input by the user, and in a case where the difference is greater than the predetermined range, the control unit performs the printing operation by changing the printing setting of the recording material input by the user, which is used when the difference is smaller than the predetermined range.

A control unit of the invention compares printing setting suitable for a determined type of a recording material and printing setting of the recording material input by a user, and in a case where a difference between the printing setting suitable for the determined type of the recording material and the printing setting of the recording material input by the user falls in a predetermined range, the control unit performs a printing operation in accordance with the printing setting of the recording material input by the user, and in a case where the difference is greater than the predetermined range, the control unit performs the printing operation by changing the printing setting of the recording material input by the user, which is used when the difference is smaller than the predetermined range.

A sheet conveying apparatus has a reference roller, a detection roller, and a detection sensor. The detection roller can move, and makes contact with the reference roller, facing the reference roller. The detection sensor outputs a signal corresponding to the displacement of the detection roller. The sheet is conveyed to a nip portion of the pair of rollers. At this time, the timing when an edge portion of the sheet being conveyed passes through the nip portion is detected. In response to the timing detected, the thickness of the sheet is detected, based on the signal output from the detection sensor.

A sheet conveying apparatus has a reference roller, a detection roller, and a detection sensor. The detection roller can move, and makes contact with the reference roller, facing the reference roller. The detection sensor outputs a signal corresponding to the displacement of the detection roller. The sheet is conveyed to a nip portion of the pair of rollers. At this time, the timing when an edge portion of the sheet being conveyed passes through the nip portion is detected. In response to the timing detected, the thickness of the sheet is detected, based on the signal output from the detection sensor.