A controller recognizes a remaining level of sheets in a sheet feeding cassette. The controller counts the required time after a sheet feeding rotary member starts to rotate until a sheet feeding sensor senses the tip end of a sheet. The controller judges whether a sheet feeding delay has occurred based on the required time. The controller calculates the incidence of sheet feeding delays for each sheet remaining level.

An image forming device comprising: a tray in which multiple number of sheets are stored; a feeder that feeds the sheet stored in the tray; and a hardware processor that: measures a carrying speed of the sheet fed by the feeder; determines whether or not the measured carrying speed is affected by the following sheet; corrects the carrying speed upon determining the carrying speed is affected by the following sheet; and detects a wear status on the feeder based on the measured carrying speed or the corrected carrying speed.

An image forming device comprising: a tray in which multiple number of sheets are stored; a feeder that feeds the sheet stored in the tray; and a hardware processor that: measures a carrying speed of the sheet fed by the feeder; determines whether or not the measured carrying speed is affected by the following sheet; corrects the carrying speed upon determining the carrying speed is affected by the following sheet; and detects a wear status on the feeder based on the measured carrying speed or the corrected carrying speed.

A sheet processing apparatus comprises a roller disposed in a sheet conveyance path; a sheet sensor disposed in the sheet conveyance path and configured to detect conveyance of sheets and generate sensor information indicative of detection; and a controller. The controller is configured to, for each sheet of a predetermined number of sheets of a plurality of sheets conveyed by the roller, use the sensor information to generate an individual sheet-conveyance dataset indicating a sheet passage interval; and store the individual sheet-conveyance dataset in data storage. The controller is further configured to, after the roller conveys the predetermined number of sheets, calculate a summary sheet-conveyance dataset including sheet passage interval statistics for the predetermined number of sheets; store the summary sheet-conveyance dataset in the data storage; discard the individual sheet-conveyance datasets from the data storage; and evaluate the sheet passage interval statistics to determine whether to modify the predetermined number of sheets.

A sheet processing apparatus comprises a roller disposed in a sheet conveyance path; a sheet sensor disposed in the sheet conveyance path and configured to detect conveyance of sheets and generate sensor information indicative of detection; and a controller. The controller is configured to, for each sheet of a predetermined number of sheets of a plurality of sheets conveyed by the roller, use the sensor information to generate an individual sheet-conveyance dataset indicating a sheet passage interval; and store the individual sheet-conveyance dataset in data storage. The controller is further configured to, after the roller conveys the predetermined number of sheets, calculate a summary sheet-conveyance dataset including sheet passage interval statistics for the predetermined number of sheets; store the summary sheet-conveyance dataset in the data storage; discard the individual sheet-conveyance datasets from the data storage; and evaluate the sheet passage interval statistics to determine whether to modify the predetermined number of sheets.

A sheet conveyance apparatus includes an oblique-feed unit configured to nip and convey a sheet by imparting to the nipped sheet a force in a direction inclined relative to a sheet conveyance direction so that the sheet approaches an abutment surface in the width direction as the sheet proceeds downstream in the sheet conveyance direction; a drive unit configured to drive the oblique-feed unit; a change unit configured to change the force of the oblique-feed unit; and a control unit configured to control the drive unit and the change unit so that, after causing the sheet to abut against the abutment surface in a first state in which the oblique-feed unit is driven at a first speed, the oblique-feed unit is put into a second state in which the oblique-feed unit is driven at a second speed higher than the first speed and the force is weaker than in the first state.

A sheet conveyance apparatus includes an oblique-feed unit configured to nip and convey a sheet by imparting to the nipped sheet a force in a direction inclined relative to a sheet conveyance direction so that the sheet approaches an abutment surface in the width direction as the sheet proceeds downstream in the sheet conveyance direction; a drive unit configured to drive the oblique-feed unit; a change unit configured to change the force of the oblique-feed unit; and a control unit configured to control the drive unit and the change unit so that, after causing the sheet to abut against the abutment surface in a first state in which the oblique-feed unit is driven at a first speed, the oblique-feed unit is put into a second state in which the oblique-feed unit is driven at a second speed higher than the first speed and the force is weaker than in the first state.

There is provided an image forming apparatus including a casing, a feeder unit, an image recording unit, a conveyance mechanism, an installation/removal sensor, and a controller. The controller carries out the process of: interrupting an image recording of the image recording unit if there is no recording medium supported by trays, restarting the image recording of the image recording unit by feeding the medium from a second tray after a first predetermined time has elapsed since such a time when the second tray is detected as the earliest one being removed and reinstalled, and restarting the image recording of the image recording unit by feeding the medium from a first tray if the first tray is detected as the earliest one but the second tray is not detected as being removed within a second predetermined time being longer than the first predetermined time.

There is provided an image forming apparatus including a casing, a feeder unit, an image recording unit, a conveyance mechanism, an installation/removal sensor, and a controller. The controller carries out the process of: interrupting an image recording of the image recording unit if there is no recording medium supported by trays, restarting the image recording of the image recording unit by feeding the medium from a second tray after a first predetermined time has elapsed since such a time when the second tray is detected as the earliest one being removed and reinstalled, and restarting the image recording of the image recording unit by feeding the medium from a first tray if the first tray is detected as the earliest one but the second tray is not detected as being removed within a second predetermined time being longer than the first predetermined time.

A displacement amount calculation part in a base material processing apparatus calculates the degree of matching between an upstream data section and a downstream data section included in a first and a second detection results, which indicate time-varying changes in the positions of an edge of a base material in the width direction at an upstream and a downstream detection positions. This calculation uses calculation results obtained by sequentially calculating the degrees of matching between sub-data sections in the upstream data section and downstream sub-data sections in the downstream data section. This reduces the amount of computation and enables highly accurate detection of the amount of displacement of the base material in the transport direction on the basis of an identification result of the downstream data section that is highly matched with the upstream data section.