An image forming apparatus is configured such that in a case where images are to be formed on a first surface of a preceding sheet, on a first surface of a succeeding sheet fed to the first conveyance path succeeding to the preceding sheet and on a second surface of the preceding sheet, a first conveyance member is stopped without reversing the preceding sheet to a second conveyance path in a case where the image has been formed on the first surface of the preceding sheet and permission of preparing the image to be formed on the first surface of the succeeding sheet is not issued yet. The first conveyance member restarts conveyance of the preceding sheet to the second conveyance path based on timing when an image forming unit starts preparing the image to be formed on the first surface of the succeeding sheet.

An image forming apparatus configured to form images on a first surface and a second surface of a sheet includes an apparatus body, an image forming unit, a feed tray, and a return unit configured to return the sheet having an image formed on the first surface of the sheet toward the image forming unit. The return unit includes a first guide, a second guide, and an adjuster. The first guide is detachably attached to the second guide and includes a first roller and a positioned portion. The second guide is positioned in the apparatus body and includes a second roller facing the first roller, and a positioning portion configured to contact the positioned portion of the first guide, thereby positioning the first guide relative to the second guide. The adjuster is configured to adjust an orientation of the second guide relative to the apparatus body.

An image forming apparatus includes: an inverting unit that inverts a sheet when an image forming process for forming images on both sides of the sheet is performed; an image forming unit that forms an image on a second side of the sheet based on first side image data and forms an image on a third side of the sheet based on second side image data; a controller that starts the image forming process upon receiving print data to be printed on specific paper, and inverts a sheet fed from a sheet feeding unit once or more; and a converting unit that, when the sheet fed from the sheet feeding unit is the specific paper, converts the first side print data which is received to be printed on the specific paper into N-th side image data where N≥2 and transfers the N-th side image data to the image forming unit.

After outputting a first start signal for causing an image forming unit to start formation of an image for a first side of an i-th sheet, a controller causes a feeding member to start feeding of the i-th sheet, and determines whether or not the i-th sheet has already been detected by a detector. In a case where the i-th sheet has been detected before a predetermined time has elapsed, the controller outputs a second start signal for causing the image forming unit to start formation of an image for second side of an (i−1)th sheet. In a case where the i-th sheet has not been detected before the predetermined time has elapsed, the controller outputs the second start signal after the i-th sheet is detected.

Copy and scan printing may include scanning, by scanner disposed along a paper path between a paper delivery roller and a paper pickup roller, content of documents (302). Further, copy and scan printing may include determining whether the documents are to be copied (304), in response to a determination that the documents are to be copied, determining whether a page count of the documents to be copied is available (306), and generating copies of the documents (310).

An image forming apparatus includes a stack portion having recording materials, an image forming unit, a basis weight detection unit, an operating sound detection unit, and a mode selection unit. The basis weight detection unit detects a recording material basis weight based on an ultrasonic wave. The operating sound detection unit detect an abnormality of a generated operating sound. The mode selection unit selects, for each recording material fed to the image forming unit, between transmitting to the basis weight detection unit a first instruction for detecting the recording material basis weight and transmitting to the operating sound detection unit a second instruction for detecting the operating sound abnormality. In determining an interval at which each second instruction is transmitted, the mode selection unit determines the interval so that the interval and a cycle, in which properties of recording materials on the stack portion are repeated, do not continuously coincide.

In an image forming apparatus capable of turning over a sheet to form images on both sides of the sheet, when duplex printing is executed successively on three or more sheets, a controller causes a first sheet conveyed from an image forming unit and a second sheet conveyed from the image forming unit to be guided into a first path by positioning a guide member in a first position, and then conveyed into a third path by a first roller, and causes a third and subsequent sheets conveyed from the image forming unit to be guided into a second path by positioning the guide member in a second position, and then conveyed into the third path by a second roller.

A printing apparatus comprising a sheet conveyance path that includes a plurality of waiting positions at which a sheet in which printing has been performed on a first side in double-sided printing is caused to wait in order to print an image on a second side of the sheet, and is able to selectively execute first print control, second print control and third print control, retains information regarding a sheet to be fed in accordance with the first to third print control in a sheet feed wait queue, and selects and executes one of the first to third print control based on a printing order of single-sided printing and double-sided printing in the print job, the number of the plurality of waiting positions, and information retained in the sheet feed wait queue.

Copy and scan printing may include scanning, by scanner disposed along a paper path between a paper delivery roller and a paper pickup roller, content of documents (302). Further, copy and scan printing may include determining whether the documents are to be copied (304), in response to a determination that the documents are to be copied, determining whether a page count of the documents to be copied is available (306), and generating copies of the documents (310).

A sheet conveyance apparatus includes a first conveyance portion configured to convey a sheet, a second conveyance portion configured to convey the sheet, the second conveyance portion including an abutment portion configured to form a loop on the sheet by being abutted against a leading edge of a sheet conveyed by the first conveyance portion, a curved guide portion, which is curved, configured to guide the sheet conveyed by the first conveyance portion to the second conveyance portion, and a rotary member arranged downstream of the first conveyance portion and upstream of the second conveyance portion in a sheet conveyance direction, and configured to be driven to rotate by a surface of the sheet that is guided by the curved guide portion, the surface sliding against the curved guide portion.