An image forming system includes first and second image forming apparatuses including respective image forming sections and fixing sections. When the system forms an image on a sheet using the first image forming section, then forms an image on the sheet using the second image forming apparatus, and forms an image on a same side of a sheet which has a nonuniform sheet thickness and first and second regions respectively having small and large sheet thicknesses, the image in the first region is formed and fixed using the first image forming apparatus and the image in the second region is formed and fixed using the second image forming apparatus, and the respective fixing sections of the first and the second image forming apparatuses pass the nonuniform sheet while applying a second load lower than a first load applied to a sheet having a uniform sheet thickness.

Provided is an image forming system in which a plurality of image forming apparatuses are tandem-connected in series. The image forming system comprises a controller that processes image data used for image formation and controlling the image forming apparatus, wherein the controller has a function of outputting an inspection image for obtaining calibration data of the image forming apparatus by the image forming apparatus and enabling acquisition of the reading result read by an image reading unit, and in the function, the controller prepares data for the inspection image to be output by one image forming apparatus and duplicates the data, and transmits inspection image data to each image forming apparatus, and performs control so that image is formed on different transfer media respectively by the respective image forming apparatuses based on the inspection image data received by each image forming apparatus.

An image forming apparatus determines whether crease processing at a plurality of portions set on the sheet includes crease processing on two, front and back surfaces of the sheet; determines, if it is determined that crease processing includes crease processing on the two surfaces of the sheet, whether a connected post-processing apparatus that performs crease processing on a sheet can perform crease processing on the two, front and back surfaces of the sheet by one feeding; and controls, if it is determined that the connected post-processing apparatus cannot perform crease processing on the two surfaces by one feeding, to change, to one of the front and back surfaces of the sheet based on attribute information of the sheet, a surface to be processed in crease processing at the plurality of portions.

An image forming system includes a first device and a second device that are connected in series. The first device can continuously discharge a paper. The second device is blocked from information on a paper conveyance in the first device. The second device, based on printing setting information and a time at which the first paper passes the predetermined position, sets a printing cycle, and based on a time at which the second paper passes the predetermined position, calculates a delay time from a printing cycle of the second paper. The second device stops a conveyance of the second paper that is conveyed to the paper processor, and in accordance with the delay time, controls resuming of the stopped conveyance of the second paper.

Provided is an image formation system of series tandem type in which first and second image formation apparatuses connected in series execute an image formation process on a recording material, wherein the first image formation apparatus includes: a first image carrier; a first toner image formation unit; a first density detection unit; a first density control value setting unit; and a first temperature detection unit, the second image formation apparatus includes: a second image carrier; a second toner image formation unit; a second density detection unit; a second density control value setting unit; and a second temperature detection unit, and the image formation system includes: a recording material density detection unit; and a control unit.

An apparatus includes multiple image processing units configured to execute image processing on input data, which are connected in serial, and include two or more image processing units having the same image processing function. The image processing units include a transfer unit configured to transfer input first data to a next image processing unit without changing the data, and an image processor configured to execute image processing on the first data to output second data. At least one of the image processing units transfers the first data to the next image processing unit without changing the first data when the first data is input, and also outputs the second data.

An image forming apparatus determines whether crease processing at a plurality of portions set on the sheet includes crease processing on two, front and back surfaces of the sheet; determines, if it is determined that crease processing includes crease processing on the two surfaces of the sheet, whether a connected post-processing apparatus that performs crease processing on a sheet can perform crease processing on the two, front and back surfaces of the sheet by one feeding; and controls, if it is determined that the connected post-processing apparatus cannot perform crease processing on the two surfaces by one feeding, to change, to one of the front and back surfaces of the sheet based on attribute information of the sheet, a surface to be processed in crease processing at the plurality of portions.

An image forming apparatus includes one or plural forming devices that form respective images on a recording medium that is being transported, a fixing device provided on a downstream side with respect to at least one of the forming devices in a direction of transport of the recording medium and that fixes the images formed on the recording medium, a delivering device that receives the recording medium transported in a first direction and discharges the recording medium in a second direction that is different from the first direction, and a supplying device that supplies the recording medium to any of the forming devices or to the delivering device. The forming devices, the fixing device, the delivering device, and the supplying device have respective housings and are each joinable to any of the other devices.

An image forming apparatus includes a housing; a partition wall which is provided in the housing along a substantially vertical direction, the partition wall partitioning an inner space of the housing into a first space and a second space; developing units which are disposed in parallel along the substantially vertical direction in the first space, each of the developing units comprising a first reception opening and a return opening; and developer cartridges which correspond to the plurality of developing units, the developer cartridges being disposed in parallel along the substantially vertical direction in the second space, each of developer cartridges comprising a supply opening and a second reception opening. The first reception openings of the developing units communicate with the supply openings of respective ones of the developer cartridges, and the return openings of the developer units communicate with the second reception openings of respective ones of the developer cartridges.

An image forming apparatus determines whether crease processing at a plurality of portions set on the sheet includes crease processing on two, front and back surfaces of the sheet; determines, if it is determined that crease processing includes crease processing on the two surfaces of the sheet, whether a connected post-processing apparatus that performs crease processing on a sheet can perform crease processing on the two, front and back surfaces of the sheet by one feeding; and controls, if it is determined that the connected post-processing apparatus cannot perform crease processing on the two surfaces by one feeding, to change, to one of the front and back surfaces of the sheet based on attribute information of the sheet, a surface to be processed in crease processing at the plurality of portions.