An image forming apparatus detects an attribute of paper for each sheet of paper. A post-process apparatus performs a post-process for each group of paper including a designated number of sheets of paper. A controller of the image forming apparatus determines for each sheet of paper, whether or not a designated post-process is prohibited based on prohibition rule data which defines permission and prohibition of the post-process in accordance with the attribute of paper for each type of post-process and the detected attribute of paper. When the controller determines that the designated post-process is prohibited, the controller determines whether or not a sheet of paper which resulted in determination as prohibition is a sheet of paper intermediate between the first sheet of paper and the last sheet of paper in the group of paper, and has an image forming system perform a process in accordance with a result of determination.

An image heating apparatus includes an image heating portion including a heater, a tubular film having an inner surface in contact with the heater, and a pressure member that is in contact with the outer surface of the film and forms a nip portion for conveying a recording material between the outer surface and the pressure member. The image heating portion heats an unfixed toner image on the recording material by the heater. A temperature detection portion detects the temperature of the heater. A control portion controls electric power to the heater such that the temperature detected by the temperature detection portion is maintained at a predetermined control target temperature. An obtainment portion obtains image information for forming the unfixed toner image. The control target temperature is set, based on the image information, for each of a plurality of regions defined by dividing the recording material in the conveying direction.

An image forming apparatus includes an image bearing member, an image transfer device for transferring a toner image from the image bearing member to a sheet, an application device for applying a transfer voltage to the image transfer device, and a controller for controlling an output mode operation for outputting a predetermined chart in which test halftone toner images transferred with different transfer voltages are formed to adjust the transfer voltage. When outputting a maximum size of the chart, the controller forms the test toner images in a region within 50 mm from an edge in a width direction perpendicular to a feeding direction of the sheet.

In an image-forming apparatus, when a sheet length of a first sheet is shorter than or equal to a predetermined length, a controller supplies power to an electromagnetic clutch to convey the first sheet and a second sheet so that a sheet gap of the second sheet is equivalent to a first gap. When the sheet length of the first sheet is longer than the predetermined length, the controller supplies power to the electromagnetic clutch to successively convey a first number of sheets so that the sheet gap of each of the first number of sheets is equivalent to the first gap. After the first number of sheets has been conveyed, the controller supplies power to the electromagnetic clutch to convey at least one sheet so that the sheet gap of each of the at least one sheet is equivalent to a second gap greater than the first gap.

An image forming apparatus includes a storing unit that stores information associated with a sheet type of a sheet and a sheet feed source, of a plurality of sheet feed sources, a selection unit that selects a sheet feed source from the plurality of sheet feeding sources based on at least a sheet type designated by a job and the stored information, and a feeding unit that feeds a sheet from the selected sheet feed source. The image forming apparatus also includes an image forming unit that forms an image on the sheet fed by the feeding unit, and a detector that detects a sheet type of the sheet fed from one of the plurality of sheet feed sources by the feeding unit. The storing unit stores the sheet type detected by the detector as the information indicating the sheet type of sheet stored in the sheet feeding source.

A printing apparatus has: a paper tray having edge guides, each of which can guide one edge of paper in its width direction intersecting the transport direction of the paper; a paper width sensor that detects a paper width allowable in the paper tray according to the positions of the edge guides; a display controller that displays, on a display unit, a paper size selection screen on which candidate paper sizes corresponding to the paper width detected by the paper width sensor are displayed; and a selected size storage section that stores, in a storage section, paper selection information in which the paper width and the paper size selected on the paper size selection screen are related to each other.

An image forming apparatus is operable in a first small-sheet printing in which power is supplied to the first heat generating element and the second heat generating element and in a second small-sheet printing in which power is supplied to the first heat generating element and the third heat generating element. A first power ratio, which is a proportion of power supplied to the first heat generating element to power supplied to the second heat generating element in the first small-sheet printing, is higher than a second power ratio, which is a proportion of power supplied to the first heat generating element to power supplied to the third heat generating element in the second small-sheet printing.

An image forming apparatus includes a fixing device having a heater that includes a first heating element, a second heating element having a length smaller than the first heating element length, and a third heating element having a length smaller than the second heating element length. The image forming apparatus further includes a first temperature detection unit, a control unit, second temperature detection units, first and second sheet-width detection units, and a determination unit. The control unit controls a heater temperature based on the first temperature detection unit detection result. The determination unit determines a width of the recording material based on a detection result of the first sheet-width detection units, a detection result of the second sheet-width detection units, and a detection result of the second temperature detection units.

An image forming apparatus includes a load detection sensor located on a feeder to detect whether a print medium is loaded on the feeder, an overload detection sensor to detect an overload state of a discharger, and a controller to detect a width of the print medium according to a combination of a feeder load state of a feeder load detection signal of the load detection sensor and an overload state of a discharger overload detection signal of the overload detection sensor and control an image former to perform printing by applying different print modes according to the detected width of the print medium.

An image forming system includes an image forming apparatus and a post-processing device. The image forming apparatus includes a scanner reading image data from a sheet, an image forming part forming an image on the sheet, and a sheet ejecting part ejecting the sheet after forming the image. The post-processing device includes a post-processing conveying path, and a stapling part. The post-processing conveying path introduces the sheet from the sheet ejecting part and conveys the sheet. The stapling part collects sheets conveyed on the post-processing conveying path for each predetermined number of sheets and executes staple processing to the sheets. The image forming apparatus or the post-processing device includes a size deciding part deciding a sheet size based on the image data. The post-processing device includes a staple controlling part determining a binding position for the staple processing on the basis of the sheet size.