In some examples, a printing press includes a support element with a circulatingly movable contact surface for contacting a printing substrate. An ink jet print head includes an ejection opening arranged to be directed at the support element. Additionally, the printing press includes a charging device that includes a charging electrode, which is arranged to be directed at the contact surface. The charging device further includes a counter-electrode, and the movable contact surface is at least partially arranged between the charging electrode and the counter-electrode of the charging device. A smallest distance between the charging electrode and the movable contact surface is greater than a smallest distance between the ejection opening of the ink jet print head and the contact surface. For example, the smallest distance between the charging electrode and the contact surface may be at least 50 mm.

A feeding device includes a loading portion, a lifting mechanism, a conveying unit, a sheet detector, a near-end detector, and process circuitry. The loading portion stacks a plurality of sheets. The lifting mechanism lifts the loading portion. The conveying unit conveys the sheets on the loading portion. The sheet detector detects presence or absence of the sheets on the loading portion at a specified height position. The sheet count detector detects a number of sheets conveyed by the conveying unit. The near-end detector detects a near-end state in which a stack height of the sheets on the loading portion is a specified value or less. The process circuitry controls the lifting mechanism based on a detection result of the sheet detector before the near-end state is detected, and controls the lifting mechanism based on a detection result of the sheet count detector after the near-end state is detected.

A sheet conveying device includes a sheet placement table, a sheet discharge table, a conveyance mechanism, raising/lowering mechanism, and a raising/lowering control portion. The sheet discharge table is located below the sheet placement table. The conveyance mechanism conveys a sheet placed on the sheet placement table onto the sheet discharge table via an execution position at which image processing is executed by an image processing portion. The raising/lowering mechanism raises and lowers the sheet placement table. The raising/lowering control portion controls the raising/lowering mechanism in accordance with a clearance that is defined by a height from the sheet on the sheet discharge table to the sheet placement table, so as to maintain the clearance to be equal to or higher than a set value.

A sheet conveying device includes a sheet placement table, a sheet discharge table, a conveyance mechanism, raising/lowering mechanism, and a raising/lowering control portion. The sheet discharge table is located below the sheet placement table. The conveyance mechanism conveys a sheet placed on the sheet placement table onto the sheet discharge table via an execution position at which image processing is executed by an image processing portion. The raising/lowering mechanism raises and lowers the sheet placement table. The raising/lowering control portion controls the raising/lowering mechanism in accordance with a clearance that is defined by a height from the sheet on the sheet discharge table to the sheet placement table, so as to maintain the clearance to be equal to or higher than a set value.

A sheet feeding apparatus includes a sheet stacker, an air blower, a suction feeder, a lifting mechanism, an elevation detection sensor, an elevation detection sensor, a feed detection sensor, and processing circuitry. The air blower blows air to float an uppermost sheet of sheets stacked on the sheet stacker. The processing circuitry drives the lifting mechanism such that the sheet stacker is lifted by an elevation amount determined based on a sheet thickness of the sheets stacked on the sheet stacker, each time a sheet is detected when a number of sheets detected is smaller than a threshold number of sheets, and stops lifting of the sheet stacker until a sheet is not detected when the number of sheets reaches the threshold number of sheets, while repeatedly feeding the uppermost sheet and counting the number of sheets.

A recording apparatus includes a recording unit, a discharge unit that discharges a medium on which recording is performed by the recording unit, and a medium receiving unit that receives a medium discharged by the discharge unit, and a medium can be fed to an optional device attached to an apparatus main body from the discharge unit. The discharge unit includes a discharge roller that discharges a medium, a forming unit that forms a medium to be discharged, and a detection unit that detects a stacking height of a medium stacked on the medium receiving unit and is located at a position where the detection unit interferes with the optional device when the optional device is attached, the detection unit and the forming unit are integrally configured, and the detection unit and the forming unit are configured to be integrally attached to and removed from the apparatus main body.

A recording apparatus includes a recording unit, a discharge unit that discharges a medium on which recording is performed by the recording unit, and a medium receiving unit that receives a medium discharged by the discharge unit, and a medium can be fed to an optional device attached to an apparatus main body from the discharge unit. The discharge unit includes a discharge roller that discharges a medium, a forming unit that forms a medium to be discharged, and a detection unit that detects a stacking height of a medium stacked on the medium receiving unit and is located at a position where the detection unit interferes with the optional device when the optional device is attached, the detection unit and the forming unit are integrally configured, and the detection unit and the forming unit are configured to be integrally attached to and removed from the apparatus main body.

A sheet conveying device includes a sheet placement table, a sheet discharge table, a conveyance mechanism, raising/lowering mechanism, and a raising/lowering control portion. The sheet discharge table is located below the sheet placement table. The conveyance mechanism conveys a sheet placed on the sheet placement table onto the sheet discharge table via an execution position at which image processing is executed by an image processing portion. The raising/lowering mechanism raises and lowers the sheet placement table. The raising/lowering control portion controls the raising/lowering mechanism in accordance with a clearance that is defined by a height from the sheet on the sheet discharge table to the sheet placement table, so as to maintain the clearance to be equal to or higher than a set value.

A sheet conveying device includes a sheet placement table, a sheet discharge table, a conveyance mechanism, raising/lowering mechanism, and a raising/lowering control portion. The sheet discharge table is located below the sheet placement table. The conveyance mechanism conveys a sheet placed on the sheet placement table onto the sheet discharge table via an execution position at which image processing is executed by an image processing portion. The raising/lowering mechanism raises and lowers the sheet placement table. The raising/lowering control portion controls the raising/lowering mechanism in accordance with a clearance that is defined by a height from the sheet on the sheet discharge table to the sheet placement table, so as to maintain the clearance to be equal to or higher than a set value.

In an example, a method may include determining a range of motion of a pick arm during lifting of the pick arm from a media stack position to a hard stop position in an image forming apparatus. The pick arm may have a pick roller at one end for picking a media sheet from a media stack and pivotally mounted at an opposite end to enable angular movement of the pick arm relative to the media stack. Further, the method may include estimating a height of the media stack based on the determined range of motion of the pick arm from the media stack position to the hard stop position. Furthermore, the method may include indicating an amount of media sheets remaining in the media stack corresponding to the estimated height.