In a medium conveying device, a projector projects light, a projection light amount of the light changes, at every fixed time, to a first projection light amount and a second projection light amount less than the first projection light amount, a receiver receives the light projected from the projector, a processor determines, at fixed sampling timings, whether a reception light amount of the receiver is at a first reception light level or a second reception light level smaller than the first reception light level, determines, when the reception light amount alternately changes to the first reception light level and the second reception light level, that a medium is not present on a conveying path, and determines, when the reception light amount is fixed to either the first reception light level or the second reception light level, that the medium is present on the conveying path.

A post-processing apparatus includes a post-processing device, an ejection device, and an ejection tray. The post-processing device executes post-processing on a medium on which an image is formed by an image forming apparatus. The ejection device ejects the medium on which the post-processing is executed by the post-processing device. The ejection tray holds the medium ejected by the ejection device. The ejection tray includes a main tray having an upper face inclined downward in an ejection direction, and a movable tray being rotatably supported by the main tray between a stacking position at which the medium ejected by the ejection device remains stacked on the upper face of the main tray and an ejection position at which the medium ejected by the ejection device slides along the upper face of the main tray.

An image forming apparatus includes a flag, a sensor, a loop controller, a detector, and an image controller. The flag is disposed between the first and second conveying units and moves when in contact with a recording material having a loop. A signal value output from the sensor varies per a flag position. The loop controller changes a recording material speed based on the signal value output. The detector detects the recording material or an image formed on the recording material and the image controller changes an image forming condition based on the detection. The detector includes first and second contacting members that move to nip the recording material. A position of the flag, for changing a signal value output from the sensor, is included in a range in which first and second contacting members are movable.

In some examples, a non-transitory machine readable medium can include instructions executable by a processing resource to assert a low print media level notification responsive to determination that a first amount of print media in a media receptacle of an imaging device is less than a set value, detect a second amount of print media in the media receptacle of the imaging device, compare the detected second amount of print media to a print media threshold that is based on the set value and a selectable print media value, and maintain the low print media level notification responsive to a determination that the detected second amount of print media is less than the print media threshold.

A sheet discharge apparatus includes a pivot member pivoting in an up-down direction by being pressed by a sheet discharged from a sheet discharging portion, with the pivot member retained by being in contact with an uppermost sheet supported on the sheet supporting portion. A control unit changes a sheet interval between a preceding sheet and a succeeding sheet and executes a first discharge operation in which at least one sheet is discharged, and a second discharge operation in which sheets are discharged by the sheet discharging portion at a first sheet interval such that the pivot member does not contact with an uppermost sheet supported on the sheet supporting portion during the second discharge operation, and the control unit acquires a number of sheets to be discharged in the second discharge operation based on a detected position of the pivot member detected during the first discharge operation.

A paper sheet sensing device includes: a sheet thickness sensor that includes a reference member and a displacement sensor, and senses a sheet thickness of a conveyed recording medium by bringing the reference member into contact with the recording medium and sensing a position of a height of the reference member with the displacement sensor, the position of the height having changed with the recording medium; a first attacher to which the sheet thickness sensor is attached; a conveyor that nips and conveys the recording medium, and is disposed adjacent to the sheet thickness sensor at a predetermined distance equal to or shorter than a length of the recording medium being conveyed, in a conveyance direction of the recording medium; and a displacement preventer that prevents a change in an output of the displacement sensor due to a shift of a relative position of the height of the reference member.

A paper feeding apparatus includes a tray, an air blower, a floating detector, and a hardware processor. In the tray, a sheet of paper is loaded. The air blower blows air to the sheet loaded in the tray to float the sheet. The floating detector is provided above the sheet loaded in the tray and detects the floating of the sheet to a predetermined level. The hardware processor causes the air blower to blow the air and determines a basis weight of the sheet loaded in the tray from an air amount that has caused the floating detector to detect the floating of the sheet.

In a medium conveying device, a projector projects light, a projection light amount of the light changes, at every fixed time, to a first projection light amount and a second projection light amount less than the first projection light amount, a receiver receives the light projected from the projector, a processor determines, at fixed sampling timings, whether a reception light amount of the receiver is at a first reception light level or a second reception light level smaller than the first reception light level, determines, when the reception light amount alternately changes to the first reception light level and the second reception light level, that a medium is not present on a conveying path, and determines, when the reception light amount is fixed to either the first reception light level or the second reception light level, that the medium is present on the conveying path.

A medium conveying apparatus includes a cover that is supported by a main body so as to be arranged in an opening position or a closing position, an arm that protrudes into a conveying path formed between the cover and the main body and is retracted from the conveying path, a lock mechanism that fixes the cover to the main body with the cover arranged in the closing position, and a mechanism that retracts the arm from the conveying path when the lock mechanism shifts from a first state in which the lock mechanism releases the cover from the main body to a second state in which the lock mechanism fixes the cover to the main body.

An image forming system includes an image forming apparatus, a first conveyance path, a sheet feeding unit, a sheet post-processing unit, and a controller. The image forming apparatus has a first feed portion, and an image forming portion. The sheet feeding apparatus has a sheet stacking portion, a second feed portion, a relay conveyance portion, and a remaining amount detecting portion. When, during continuous printing, the existing number of recording sheets present in a conveyance passage from a confluence portion to the first feed portion is more than the constituting number of recording sheets contained in one bundle of sheets and in addition the sensing result of the remaining amount sensor is equal to or less than a predetermined amount, the controller controls first feed portion such that the existing number of the recording sheets is less than the constituting number of recording sheets.