A belt device includes a belt member, a detected unit, a window, an optical detector, and a regulation member. The belt member is movable in a direction of belt movement. The detected unit disposed on at least one side of the belt in a width direction of the belt intersecting with the direction of belt movement and extending in the direction of belt movement. The window transmits detection light emitted toward the detected unit and reflected light from the detected unit. The optical detector detects the detected unit. The regulation member is disposed on at least one side in a width direction of the window to keep the detected unit away from the window.

A fixing device includes a heated rotational body, a heating unit, a pressing rotational body, a pressing mechanism, a drive unit, a position recognition part, a rotational state determination part, a drive control part, and a pressing control part. The heated rotational body has a pattern. The position recognition part is configured to recognize a specific point contained in the pattern at a prescribed period. The rotational state determination part is configured to determine a variation in a rotational speed of the heated rotational body and a meandering state of the heated rotational body based on a position of the specific point recognized at the prescribed period. The drive control part is configured to control the drive unit based on the variation in the rotational speed. The pressing control part is configured to control the pressing mechanism based on the meandering state.

A fixing apparatus includes a fixing belt, a pressing roller configured to form a nip by pressing the fixing belt and rotate the fixing belt, a bush configured to guide an edge of the fixing belt, and a meandering adjustment member configured to move a rotation shaft of the pressing roller in a direction perpendicular to an axis direction of the pressing roller. The fixing apparatus can be provided to an image forming apparatus.

A fixing device comprises a heating belt and a magnetic permeability detection device. The heating belt includes an endless belt having a metal layer and a heat source. The magnetic permeability detection device is located adjacent the heating belt to detect a magnetic permeability from the metal layer of the heating belt.

An image forming apparatus includes an intermediate transfer belt, an image forming device, a brush roller, a bias application device, and a controller. The bias application device applies, between the intermediate transfer belt and the brush roller, a bias for shifting a charged residual toner from the intermediate transfer belt to the brush roller. The controller controls, in a period in which calibration or maintenance is executed, the bias application device to set an application amount of the bias at a predefined first value only in a specified time zone in which the residual toner is present on the intermediate transfer belt and to set the application amount of the bias at a predefined second value smaller than the first value in time zones other than the specified time zone.

An image forming apparatus includes an intermediate transfer belt, an image forming device, a brush roller, a bias application device, and a controller. The bias application device applies, between the intermediate transfer belt and the brush roller, a bias for shifting a charged residual toner from the intermediate transfer belt to the brush roller. The controller controls, in a period in which calibration or maintenance is executed, the bias application device to set an application amount of the bias at a predefined first value only in a specified time zone in which the residual toner is present on the intermediate transfer belt and to set the application amount of the bias at a predefined second value smaller than the first value in time zones other than the specified time zone.

An example fixing device comprises a heating belt and a magnetic permeability detection device. The heating belt includes an endless belt having a metal layer and a heat source. The magnetic permeability detection device is located adjacent the heating belt to detect a magnetic permeability from the metal layer of the heating belt.

A fixing apparatus includes a fixing belt, a pressing roller configured to form a nip by pressing the fixing belt and rotate the fixing belt, a bush configured to guide an edge of the fixing belt, and a meandering adjustment member configured to move a rotation shaft of the pressing roller in a direction perpendicular to an axis direction of the pressing roller. The fixing apparatus can be provided to an image forming apparatus.

A color printing unit includes one printing station for each color along with one anode roller. A continuous transfer belt is guided over a deflection roller and a control roller. One or more sensors measure a property of reference markings printed on the transfer belt. A control device for controlling and adjusting the transfer belt acts on the control roller through an actuating motor as a function of the detected properties of the reference markings. The one or more sensors are arranged in the area of the control roller for the transfer belt, by which an additional tension roller saves costs and space. During the measurement, at least for the period in which the printed reference markings pass under the one or more sensors, relative movements between the one or more sensors and the control roller are ruled out.

The intermediate transfer unit includes: an endless intermediate transfer belt which is turned around while carrying a toner image on its outer circumferential surface; and a plurality of rollers on which the intermediate transfer belt is turnably stretched, wherein the intermediate transfer belt has, on its inner circumferential surface, an information recording area in which belt information has been recorded, and the intermediate transfer belt has a mark at a position in the outer circumferential surface where a positional relationship between the mark and the information recording area comes to a specified relationship.