An image forming apparatus operable at a plurality of image forming speeds includes a pattern detection unit configured to detect a registration correction pattern at a first image forming speed, a writing start timing determination unit configured to determine writing start timing at which an electrostatic latent image is started to be written on a photosensitive member by a light beam emitted from a light source, and a storage unit configured to store in advance a correction amount for correcting the writing start timing. When the image forming apparatus operates at the first image forming speed set in advance, an image is formed at the writing start timing determined by the writing start timing determination unit. When the image forming apparatus operates at a second image forming speed, an image is formed at a writing start timing corrected based on the correction amount and a speed ratio.

An image forming apparatus includes an image reading device; an image forming device including a photoconductor, a charger, an exposure device including a light-emitting element, a memory to store a first correction value for correction a light emission amount of the light-emitting element, and a driver to drive the light-emitting element, a developing device, a transfer device, and a fixing device. The image forming apparatus further includes a processor to calculate a second correction value for correcting the light emission amount, based on density data of image data of a predetermined pattern on a recording medium; calculate a third correction value for correcting the light emission amount, based on the first correction value and the second correction value; and determine, before calculating the third correction value, whether placement of the recording medium on the reading table is correct based on the density data.

An image forming apparatus operable at a plurality of image forming speeds includes a pattern detection unit configured to detect a registration correction pattern at a first image forming speed, a writing start timing determination unit configured to determine writing start timing at which an electrostatic latent image is started to be written on a photosensitive member by a light beam emitted from a light source, and a storage unit configured to store in advance a correction amount for correcting the writing start timing. When the image forming apparatus operates at the first image forming speed set in advance, an image is formed at the writing start timing determined by the writing start timing determination unit. When the image forming apparatus operates at a second image forming speed, an image is formed at a writing start timing corrected based on the correction amount and a speed ratio.

An image forming apparatus includes an image reading device; an image forming device including a photoconductor, a charger, an exposure device including a light-emitting element, a memory to store a first correction value for correction a light emission amount of the light-emitting element, and a driver to drive the light-emitting element, a developing device, a transfer device, and a fixing device. The image forming apparatus further includes a processor to calculate a second correction value for correcting the light emission amount, based on density data of image data of a predetermined pattern on a recording medium; calculate a third correction value for correcting the light emission amount, based on the first correction value and the second correction value; and determine, before calculating the third correction value, whether placement of the recording medium on the reading table is correct based on the density data.

An image forming system includes an image forming device, a reading device and a hardware processor. The image forming device includes an image former that forms an image on a sheet. The reading device includes a line sensor and a lens unit. The line sensor reads the sheet with the image formed, thereby obtaining a read image. The lens unit includes a plurality of lenses and forms an image of the sheet on the line sensor. The hardware processor identifies a sheet region of the sheet in the read image, and corrects a magnification of each subregion in a main scanning direction of the sheet region according to a characteristic of a portion in the main scanning direction of the lens unit, the portion having being used in forming an image of the subregion on the line sensor.

A method and system for controlling and adjusting marker timing for a marking system comprises receiving data from a plurality of sensors in a marking system, evaluating a performance of each of the sensors in the marking system determining a marker timing offset for the marking system according to the performance of the sensor, updating marker timing of the marking system according to the marker timing offset, and marking media with the marking system according to the marker timing.

An image forming system includes an image forming device, a reading device and a hardware processor. The image forming device includes an image former that forms an image on a sheet. The reading device includes a line sensor and a lens unit. The line sensor reads the sheet with the image formed, thereby obtaining a read image. The lens unit includes a plurality of lenses and forms an image of the sheet on the line sensor. The hardware processor identifies a sheet region of the sheet in the read image, and corrects a magnification of each subregion in a main scanning direction of the sheet region according to a characteristic of a portion in the main scanning direction of the lens unit, the portion having being used in forming an image of the subregion on the line sensor.

An image reading device including: a motor to reciprocate a carriage, a reference position detector to detect passage and non-passage of the carriage through a reference position and output a detection result, and circuitry configured to, in a case where an abnormality of a stop position of the carriage has been detected based on the detection result, specify a location at which the carriage has abnormally stopped.

An image reading device includes a visible light source to irradiate a document with a visible light beam, an infrared light source to irradiate the document with an infrared light beam, and multiple mirrors disposed in optical paths of the visible light beam and the infrared light beam from the document to an imaging device. The multiple mirrors include at least a mirror having a reflectance of 93% or more, at a reflection angle of 45, to a light beam having a wavelength range of 450 nm or more and 900 nm or less.

An image reading device includes a contact glass, an automatic document feeder, a first reading module, a second reading module, a white reference member, a swinging mechanism, one motor, and a control portion. The swinging mechanism swings the second reading module or white reference member in a direction orthogonal to the conveyance direction. The control portion, by rotating a motor forward, drives a conveying member to convey a document and, by rotating the motor reversely, drives the swinging mechanism with the conveying member at rest to swing the second reading module or white reference member and meanwhile acquire white reference data. When performing a duplex reading process successively for a plurality of sheets of a conveyed document, the control portion acquires the white reference data with the document at rest closely upstream of the second reading module in the conveyance direction.