An optical scanning apparatus includes first and second light sources, a rotatable polygonal mirror, a motor, first and second mirrors, first and second lenses, and a casing. Within a mounting range, a top wall of an accommodating portion is provided with at least one projection projecting toward an opening of the accommodating portion. The projection extends from a first side wall to a second side wall of the accommodating portion. The top wall includes a recess formed opposite from the projection, and is free from a portion projecting toward the opening over a range from the first side wall to the second side wall, other than the projection in the mounting range. A free end portion of the projection is in a position remoter from the opening than a reflecting surface of the rotatable polygonal mirror is with respect to a rotational axis direction of the motor.

An optical scanning apparatus includes first and second light sources, a rotatable polygonal mirror, a motor, first and second mirrors, first and second lenses, and a casing. Within a mounting range, a top wall of an accommodating portion is provided with at least one projection projecting toward an opening of the accommodating portion. The projection extends from a first side wall to a second side wall of the accommodating portion. The top wall includes a recess formed opposite from the projection, and is free from a portion projecting toward the opening over a range from the first side wall to the second side wall, other than the projection in the mounting range. A free end portion of the projection is in a position remoter from the opening than a reflecting surface of the rotatable polygonal mirror is with respect to a rotational axis direction of the motor.

An image forming apparatus includes: a transporter; an image former; a reflective optical sensor; an image density adjuster; and a controller. The image former includes: a photoreceptor; a charger; an exposer; a developer; a transferor; and a fuser. The reflective optical sensor is provided opposite to the photoreceptor across a conveyance path. During image density adjustment, the controller forms a predetermined patch toner image on the photoreceptor, irradiates the patch toner image with light, and control the image density adjuster to adjust image density based on reflected light from the patch toner image. During image forming, the controller causes the reflective optical sensor to emit light on timing that a predetermined leading edge area of the recording area passes, and decides based on reflected light therefrom whether a width in the main scanning direction of a recording medium is longer than a predetermined reference length.

An image forming apparatus includes: a transporter; an image former; a reflective optical sensor; an image density adjuster; and a controller. The image former includes: a photoreceptor; a charger; an exposer; a developer; a transferor; and a fuser. The reflective optical sensor is provided opposite to the photoreceptor across a conveyance path. During image density adjustment, the controller forms a predetermined patch toner image on the photoreceptor, irradiates the patch toner image with light, and control the image density adjuster to adjust image density based on reflected light from the patch toner image. During image forming, the controller causes the reflective optical sensor to emit light on timing that a predetermined leading edge area of the recording area passes, and decides based on reflected light therefrom whether a width in the main scanning direction of a recording medium is longer than a predetermined reference length.

An optical scanning apparatus includes first and second light sources, a rotatable polygonal mirror, a motor, first and second mirrors, first and second lenses, and a casing. Within a mounting range, a top wall of an accommodating portion is provided with at least one projection projecting toward an opening of the accommodating portion. The projection extends from a first side wall to a second side wall of the accommodating portion. The top wall includes a recess formed opposite from the projection, and is free from a portion projecting toward the opening over a range from the first side wall to the second side wall, other than the projection in the mounting range. A free end portion of the projection is in a position remoter from the opening than a reflecting surface of the rotatable polygonal mirror is with respect to a rotational axis direction of the motor.

A pixel clock generating device includes a high-frequency clock generator, a comparer, a pixel clock generator, and a value switcher. The high-frequency clock generator is configured to generate a high-frequency clock. The comparer is configured to measure a time interval between a leading-end synchronizing signal and a trailing-end synchronizing signal in a main scanning and calculate an error between the time interval and a target value. The pixel clock generator is configured to generate a pixel clock based on the high-frequency clock and a pixel clock frequency and correct the pixel clock based on the error. The value switcher, including a plurality of groups of values with which the pixel clock is generated, is configured to switch between the plurality of groups of values according to a switching signal after the trailing-end synchronizing signal is inputted, the comparer calculates the error, and the pixel clock generator corrects the pixel clock.

An image forming apparatus member includes a surface layer containing a Si-atom containing polymer as a major component. The dispersive component of the surface free energy of the surface layer is 25 mN/m or less, the dipole component of the surface free energy of the surface layer is 5 mN/m or less, and the hydrogen bonding component of the surface free energy of the surface layer is 5 mN/m or less.

In accordance with an embodiment, an image forming apparatus comprises a main scanning counter, a controller, and an interval determination section. The main scanning counter counts a first count value indicating the number of times a synchronization signal for synchronization between the apparatuses is input to itself, and registers the first count value to an initial value if a main scanning reference signal indicating a progress state of exposure in a main scanning direction is input to itself. The controller generates PreHSYNC generated at the same interval as the main scanning reference signal. The interval determination section determines that an abnormality occurs in the main scanning reference signal if the first count value satisfies a predetermined condition at a timing at which the PreHSYNC is input to itself.

A sheet discharging device includes a stacking portion configured to stack a sheet; a discharging portion configured to feed the sheet so as to be discharged to the stacking portion, wherein the discharging portion includes a first roller configured to feed the sheet and a second roller provided so as to be contactable to a sheet surface opposite from another sheet surface to which the first roller is contactable to; and an electrically discharging member configured to electrically discharge the sheet in contact with the sheet fed by the discharging portion. As viewed in a widthwise direction perpendicular to a discharging direction of the sheet, the electrically discharging member is provided so as to extend through between rotational axes of the first and second rollers in the discharging direction of the sheet.

An image forming apparatus includes a reading unit with a fixed reading position and configured to read a first image on a sheet and detect a position of the first image. A toner image transfer unit is configured to transfer a toner pattern to the sheet at a fixed transfer position. The toner pattern corresponds to a second image to be disposed on the sheet with the first image. The toner image transfer unit is downstream of the reading unit along the sheet feeding path. A control unit calculates a timing for transfer of the toner pattern to the sheet according to the detected position of the first image on the sheet and controls the toner image transfer unit according to the calculated timing.