An example method for estimating a media level of a media stack in a printer includes storing a media level model correlating a picker metric of a media picker to pick media from the media stack to the media level; measuring a current picker metric when the media picker picks the media from the media stack during a print job; adding the current picker metric to a historical data set; updating the media level model by generating a regression for the historical data set; and based on the current picker metric and the updated media level model, estimating a current media level of the media stack.

A sheet post-processing device is connected to a punch processing unit. The punch processing unit includes a skew detection unit and a punch unit. The skew detection unit detects a skew amount of a sheet. The punch unit forms punch holes at positions of the sheet according to the skew amount. The sheet post-processing device includes a processing tray, a paddle, a driver, and a control unit. The sheet of which the skew amount is detected by the skew detection unit is mounted on the processing tray. The paddle conveys the sheet on the processing tray by a paddle operation. The driver drives the paddle to perform the paddle operation. The control unit is configured to operate the driver to control a number of times the paddle operation is performed by the paddle based on the skew amount.

A rotation device rotates a sheet on an upstream side of, in a sheet conveyance orientation, a working device positioned in a middle of a conveyance path, thereby changing an orientation of the sheet. An information acquiring portion acquires sheet size information and sheet orientation information representing a size and the orientation of the sheet in a sheet storing portion, and working position information representing a working position on the sheet. A rotation control portion controls the rotation device in accordance with the sheet orientation information and the working position information. The working control portion controls the working device in accordance with the orientation of the sheet after passing through the rotation device, and the sheet size information and the working position information.

A sheet conveying device and a sheet conveying method whereby it is possible to convey a sheet more accurately. This sheet conveying device includes a holder capable of holding a sheet, bringing the sheet into a stretched state while holding the sheet, and conveying the held sheet. This sheet conveying device also includes a sheet state recognizer that recognizes the state of the sheet when the sheet is held in a stretched state by the holder.

A sheet conveying device and a sheet conveying method whereby it is possible to convey a sheet more accurately. This sheet conveying device includes a holder capable of holding a sheet, bringing the sheet into a stretched state while holding the sheet, and conveying the held sheet. This sheet conveying device also includes a sheet state recognizer that recognizes the state of the sheet when the sheet is held in a stretched state by the holder.

An image forming device includes a tray on which a sheet is to be placed and including a plurality of first electrodes arranged along a first direction, a sheet guide including a conductor and movable along the first direction to different positions relative to the first electrodes, a detection circuit electrically connected to each of the first electrodes and configured to detect an amount of electric charge in each of the first electrodes, a printer configured to form an image on the sheet supplied from the tray, and a processor configured to determine a size of the sheet placed on the tray based on amounts of electric charge detected by the detection circuit, and control the printer to form an image on the sheet using the determined size.

A sheet feeding apparatus includes a sheet supporting unit, a sheet feed unit, an air separation unit configured to separate the uppermost sheet by blowing the air onto a side surface of the sheet bundle supported by the sheet supporting unit, a velocity detection unit configured to detect actual velocity of a sheet fed by the sheet feed unit, a drive load detection unit configured to detect an actual drive load for feeding the sheet by the sheet feed unit, and a controller configured to control the sheet feed unit and the air separation unit. In a case where the sheet is fed by the sheet feed unit, the controller is configured to control an operation of the air separation unit depending on the actual velocity of the sheet detected by the velocity detection unit and the actual drive load detected by the drive load detection unit.

A sheet transport device includes a processor configured to change lifting control for lifting sheets on a tray, which are to be floated up and handed over, from normal state control to small-quantity state control in a case where it is detected that the remaining number of sheets on the tray is small.

A sheet transport device includes a processor configured to change lifting control for lifting sheets on a tray, which are to be floated up and handed over, from normal state control to small-quantity state control in a case where it is detected that the remaining number of sheets on the tray is small.

A medium ejection apparatus including: a placement mount on which media are placed; a medium-leading-edge position restriction part that moves between a restriction position at which the restriction part restricts a position of a leading edge portion of a medium ejected toward the placement mount with reference to an ejection direction of the medium and a retracted position retracted from the restriction position; and a medium position control unit that controls the medium-leading-edge position restriction part such that the medium-leading-edge position restriction part performs a leading-edge restriction operation of moving from the retracted position to the restriction position and moving from the restriction position to the retracted position when the medium-leading-edge position restriction part and an upper surface of a medium are not in contact with each other.