A document conveying device includes a document tray, a first rotary member, a first motor, a second rotary member, a second motor, a document feed sensor, and a controller. The controller counts a counted time from the time point that the first motor starts to rotate until the leading end of a document reaches the document feed sensor. When the time resulting from subtracting the counted time from a required sheet-to-sheet time interval is longer than the required speed change time, the controller performs deceleration and post-deceleration acceleration for the first motor. The required speed change time is the time required for speed change from the first rotation speed to the second rotation speed.

To provide a post-processor capable of executing alignment processing with high accuracy.

Configuring a post-processor including: a recording material loader on which a recording material conveyed through a conveyance path is loaded; an aligner that aligns the recording material in the recording material loader; a driver that moves the aligner; and a controller that receives information of a physical property value of the recording material acquired by a medium sensor and determines an operation parameter of alignment processing that drives the driver based on the information of the physical property value.

To provide a post-processor capable of executing alignment processing with high accuracy.

Configuring a post-processor including: a recording material loader on which a recording material conveyed through a conveyance path is loaded; an aligner that aligns the recording material in the recording material loader; a driver that moves the aligner; and a controller that receives information of a physical property value of the recording material acquired by a medium sensor and determines an operation parameter of alignment processing that drives the driver based on the information of the physical property value.

To ensure reliable and productive processing of printed sheets into stacks, a sheet stacker includes: a flipping device for flipping a sheet with respect to the sheet's orientation before being received by the flipping device onto a stack support or a stack of sheets on the stack support; a sensor assembly for detecting an out-of-plane deformation of a top sheet with respect to the underlying stack support or a stack of sheets on the stack support at least for each sheet added to the stack; and a controller configured to determine from data from the sensor assembly whether the top sheet was successfully flipped and stacked.

A printing system for printing on sheets of media having a non-uniform thickness profile. A user interface is controlled to instruct the operator to load a media tray with a stack of media having a specified pattern of media orientations. A media transport system picks sequential sheets of media from the media tray. A front end supplies sequential image data having orientations in accordance with the specified pattern of media orientations. A printing module sequentially prints the supplied image data on the sheets of media in accordance with the specified pattern of media orientations.

A printing system for printing on sheets of media having a non-uniform thickness profile. A user interface is controlled to instruct the operator to load a media tray with a stack of media having a specified pattern of media orientations. A media transport system picks sequential sheets of media from the media tray. A front end supplies sequential image data having orientations in accordance with the specified pattern of media orientations. A printing module sequentially prints the supplied image data on the sheets of media in accordance with the specified pattern of media orientations.

A conveyance device includes a conveyance roller, a registration roller, a sensor, a mode setting part, a storage, a conveyance state determination part and a drive control part. The mode setting part sets the mode to either a plain paper mode or a tab paper mode. The storage stores threshold information corresponding to the mode. The conveyance state determination part determines, when the plain paper mode is set, whether the conveyance state of the recording medium is a skew conveyance state or a tab paper conveyance state, based on the detection result of the sensor and the plain paper mode threshold information. The conveyance state determination part determines, when the tab paper mode is set, whether the conveyance state of the recording medium is the skew conveyance state or the tab paper conveyance state, based on the detection result of the sensor and the tab paper mode threshold information.

A medium conveying apparatus includes a moving mechanism to move the set guide, a guide pair including a first guide having a first opening and a second opening, and a second guide to regulate a vertical direction of the medium conveyance path, a light emitting element and a light receiving element located on an outside of the medium conveyance path with the first guide in between, and on the downstream side of the first opening and the second opening so as to be apart from the moving mechanism by a predetermined distance or more in the medium conveying direction, a first light guide which is bent so as to guide a light emitted from the light emitting element to the first opening, and a second light guide which is bent so as to guide the light incident from the second opening to the light receiving element.

A sheet feeder apparatus includes a width detector for a sheet placed on a sheet placement portion, a conveyor for conveying sheets while separating the sheets one by one, a first detector for detecting a sheet having a first width at a plurality of first positions, a second detector for detecting a sheet having a second width that is not detected by the first sheet detector at a plurality of second positions, and a controller for determining skewing of a sheet based on a result of the detection of the sheet performed by the first detector if the width of the sheet is the first width, and determining skewing of a sheet based on a result of the detection performed by the second detector if the width of the sheet is the second width.

A feeder of a sheet treating or a sheet processing machine comprises a sensor system, which sensor system, on a front side pointing in a direction of transport of the sheets to be fed or on the opposing, rear side of the pile of sheets to be fed, comprises one or more sensors, by the use of which sensors, a distance, with respect to at least two locations, which are spaced apart from one another transversely to the transport direction, at the relevant front or rear sides of the pile, can be ascertained. A method is provided for detecting or correcting sheets having deviated positions or dimensions in such a sheet feeder of a sheet treating or processing machine.