Patent ID: 9742944
Date: 2017-08-22
CPC Classifications: H04N

Claim:
1. An image forming apparatus comprising: a recording sheet supply portion configured to feed a recording sheet; a double-sided image forming portion capable of forming an image on each of a first recording surface of the recording sheet and a second recording surface opposite the first recording surface, respectively, of the recording sheet, while conveying the recording sheet supplied from the recording sheet supply portion; a divided image acquiring portion configured to acquire a pair of divided images each constituting a half of an original image; an image forming control portion configured to supply a folded recording sheet that is the recording sheet folded in half to the double-sided image forming portion, and cause the double-sided image forming portion to perform processing of forming the pair of divided images on the first recording surface and the second recording surface, respectively, of the folded recording sheet; a processor configured to execute a mode selecting portion, wherein the mode selecting portion is configured to select one of a first image forming operation mode and a second image forming operation mode, the first image forming operation mode being an operation mode in which the folded recording sheet is supplied to the double-sided image forming portion, the second image forming operation mode being an operation mode in which the recording sheet that is not folded is supplied to the double-sided image forming portion; and a first detecting portion configured to detect an overlapping state of the recording sheet based on levels of detection signals of transmitted waves resulting from ultrasonic waves at two detected portions of the recording sheet, wherein the image forming control portion includes a conveyance control portion configured to, when the first image forming operation mode is selected by the mode selecting portion, set a conveyance speed of the recording sheet to a lower speed than when the second image forming operation mode is selected by the mode selecting portion, wherein the two detected portions are portions of the recording sheet fed from the recording sheet supply portion that are located at positions close to opposite ends in a width direction orthogonal to a feeding direction of the recording sheet, wherein the processor is configured to determine that one of the detected portions is a folded-back portion of the folded recording sheet and select the first image forming operation mode when a level of a detection signal of each of the two detected portions that is outputted from the first detecting portion and a level difference between the detection signals of the two detected portions satisfy a predetermined first condition, and select the second image forming operation mode when the level of the detection signal of each of the two detected portions that is outputted from the first detecting portion and the level difference between the detection signals of the two detected portions do not satisfy the first condition, and wherein when the first image forming operation mode is selected by the mode selecting portion, the image forming control portion causes the double-sided image forming portion to perform processing of forming the pair of divided images on the folded recording sheet such that edges of the pair of divided images, each forming a dividing line on the original image, extend along a fold line of the folded recording sheet, with the fold line of the folded recording sheet being at one of the opposite ends of the folded recording sheet in the width direction, the one of the opposite ends being determined by a result of a comparison between levels of two detection signals of the two detected portions outputted from the first detecting portion.