An image forming apparatus includes an image forming unit to form an image on a sheet, first and second rollers, a motor, a phase determiner, a controller, a current detector, and a discriminator. The motor drives the first roller which conveys the sheet. The second roller is downstream from the first roller. The phase determiner determines a rotation phase of a rotor of the motor. The controller controls a drive current flowing through a motor winding to reduce a deviation between a command phase representing a rotor target phase and the determined rotation phase. The current detector detects the drive current flowing through the winding. The discriminator determines a type of the sheet conveyed by the first roller based on a value of the drive current detected in a state in which the sheet is deflected while being conveyed by the first roller and not conveyed by the second roller.

An image forming apparatus includes a feeder including a tray and a pickup member, a size determiner, a sheet type setter, and a controller. The tray stacks a sheet thereon, and the pickup member feeds a contacted sheet. The feeder switches between a first state where the pickup member and the stacked sheet are in contact and a second state where the pickup member and the stacked sheet are separate. The size determiner determines a stacked sheet size. The sheet type setter sets a stacked sheet type. Where the type of the set sheet is a first type, the feeder switches from the second state to the first state when the size of the sheet is determined. Where the type of the set sheet is a second type, the feeder refrains from switching from the second state to the first state even when the size of the sheet is determined.

An image forming apparatus includes an image forming unit, a transmission unit, a reception unit, a control unit configured to obtain a time period until the reception unit receives a first ultrasonic wave via a first recording material and an amplitude value thereof at a reference temperature, obtain a time period until the reception unit receives a second ultrasonic wave via a second recording material and an amplitude value thereof at a different temperature, control an image formation condition for forming the image on the first recording material on the basis of the amplitude value of the first ultrasonic wave, obtain a difference time period between reception of the first and second ultrasonic waves, and control an image formation condition for forming the image on the second recording material on the basis of the difference time period and the amplitude value of the second ultrasonic wave.

An image forming apparatus forms an image designated by a job on a sheet fed from one of paper feed sources. Detection unit for detecting paper types of sheets respectively fed from the paper feed sources is provided on a conveyance path used in common for the fed sheets, and the detected paper types are held in one-to-one correspondence with the paper feed sources. The apparatus also hold a job-designated paper size and a job-designated paper type or a condition related to setting of a paper type. If the job includes the condition, a paper feed source that satisfies the condition is selected with reference to the paper sizes and the paper types set by the user and/or the paper types detected by the detection unit in one-to-one correspondence with the paper feed sources.

An image forming apparatus including a conveyance unit, a sheet detection unit, an operation unit, a control unit, and an image forming unit, wherein in a state where the operation unit displays first sheet information based on a detection result of detecting, by the sheet detection unit, physical properties of the sheet conveyed by the conveyance unit and conveyance of the sheet is stopped by the conveyance unit, in a case where the operation unit receives a user instruction to change the first sheet information displayed by the operation unit, the conveyance unit resumes conveyance of the sheet, the control unit sets a second image forming condition corresponding to second sheet information obtained after changing the first sheet information by a user, and the image forming unit forms the image on the sheet based on the second image forming condition.

A control unit determines sheet information based on a result of detection performed by a media sensor, and in a case where a threshold is changed after the determined sheet information is displayed on a display, the control unit determines sheet information based on the result of the detection and the changed threshold, and the display displays the sheet information.

A transfer device includes an image bearer and a transfer rotator. The transfer device further includes an adjuster including a rotatable cam and an opposed member opposed to the cam. The cam alternately contacts and separates the transfer rotator against and from the image bearer, having a continuous sloped surface with a plurality of positions, each position to contact the opposed member to obtain a different amount of separation between the image bearer and the transfer rotator. The transfer device further includes a controller to control the adjuster to adjust the amount of separation between the transfer rotator and the image bearer according to thickness or type of the recording medium when the recording medium starts to enter the transfer nip.

An optical sensor includes a light source; and an optical detector detecting intensity of light that is reflected by a recording medium, the light from the light source and irradiated onto the recording medium. Further, when an incident angle of the light incident to the recording medium from the light source relative to a normal line of the recording medium is given as 1, a formula 75185 is satisfied.

An optical sensor includes a light source; and an optical detector detecting intensity of light that is reflected by a recording medium, the light from the light source and irradiated onto the recording medium. Further, when an incident angle of the light incident the recording medium from the light source relative to a normal line of the recording medium is given as 1, a formula 75185 is satisfied.

An image forming apparatus or an image forming system, includes a control section to control, at the time of forming an image by using a long sheet with a conveying direction sheet length longer than that of a sheet with a fixed paper size, so as to perform image formation by arranging multiple images on the long sheet, and the control section controls so as to form images repeatedly with a predetermined cycle on the long sheet, detects a margin region being a region where images are not formed on the long sheet, and controls image formation so as to dispose a patch image on the margin region.