An image forming apparatus which forms an image on a medium on the basis of an input image signal includes: an image carrier configured to carry a developed toner image transferred to the medium on a photoreceptor layer; a contact member arranged so as to be in contact with the surface of the photoreceptor layer; a trace pattern generating unit configured to generate a trace pattern indicating specific information on the image forming apparatus; a composition unit configured to add the trace pattern to the image signal; and an acquiring unit configured to acquire information on the thickness of the photoreceptor layer of the image carrier, wherein the trace pattern is used for arranging a plurality of image areas at respective positions, and the trace pattern generating unit is configured to generate the trace pattern with the image area whose size is reduced in accordance with reduction of the thickness of the photoreceptor layer.

An image forming apparatus including: a light irradiating unit configured to irradiate a photosensitive member charged by a charging unit with light to form an electrostatic latent image; a processing unit configured to generate M-bit (M is an integer not less than 2) density data indicating a density based on the input image data, to generate (M+N)-bit processing data based on the M-bit density data and N-bit (N is an integer not less than 1) correction data, to convert the processing data into a plural-bit binary drive data corresponding to a value of the processing data, and to serially output the plural-bit drive data bit by bit to generate a drive signal; and a drive unit configured to drive the light irradiating unit based on the drive signal.

An image forming apparatus includes a photosensitive member, a charging member, an exposure member, a rotatable developer carrying member, a voltage source, and a controller configured to control the voltage source so that when a humidity of an inside of the apparatus is a first humidity, a developing bias voltage including an oscillating portion having an oscillating voltage and a rest portion having a substantially constant voltage are alternately repeated is outputted and so that when the humidity of the inside of the apparatus is a second humidity lower than the first humidity, a developing bias voltage in which the rest portion is not included or is shorter than the rest portion when the humidity of the inside of the apparatus is the first humidity.

A detection apparatus includes an image sensing device having an image sensing plane including a first periodic structure; and an optical system configured to illuminate a detection target including a second periodic structure different from the first periodic structure, and form an image of light from the detection target on the image sensing plane. Light having entered the image sensing plane generates a plurality of diffracted light beams of different orders in accordance with the first periodic structure. A normal of the image sensing plane is tilted with respect to an optical axis of the optical system such that the optical axis is located between diffracted light beams of adjacent orders not less than a first order among the plurality of diffracted light beams.

An image forming apparatus includes a printer unit that prints an image on a sheet using a line head in which a plurality of light emitting devices are arranged, and a storage unit that stores information regarding light amounts corresponding to the light emitting devices of the line head. The image forming apparatus generates a mask pattern based on the information regarding the light amounts obtained from the storage unit and a target light amount, and executes mask processing on halftone image data that is in positional correspondence with the light emitting devices using the generated mask pattern.

An image processing apparatus converts, according to light on an image printed based on input image data, the input image data into image data for illumination output superimposed on the image, includes a deriving unit deriving an observing condition, an estimating unit estimating luminance characteristics based on the observing condition and reflectance characteristics corresponding to print image data, an introducing unit introducing target luminance characteristics based on the print luminance characteristics, a setting unit setting illumination converting characteristics converting the input image data into the image data for illumination output based on the print luminance characteristics and the target luminance characteristics, and a converting unit converting gradation of the input image data using the illuminance characteristics, and the introducing unit introducing the target luminance characteristics such that, when reproducing ranges in the print luminance characteristics are different, a linear region of output luminance of relatively large reproducing range becomes larger.

An image forming system includes an image forming unit including a first photosensitive member, a first developing unit, a second photosensitive member, a second developing unit, a third photosensitive member, a third developing unit, a fourth photosensitive member, and a fourth developing unit, a varnish applying unit; an irradiation unit; and a controller configured to control image formation by the image forming unit to form a black image, on which the varnish is superimposed, with the yellow toner, the magenta toner, and the cyan toner.

An image forming apparatus comprising a printer unit that prints an image on a sheet using a line head in which a plurality of light emitting devices are arranged, and a storage that stores information regarding light amounts corresponding to the light emitting devices of the line head. The image forming apparatus generates a mask pattern based on the information regarding the light amounts obtained from the storage and a target light amount, and executes mask processing on halftone image data that is in positional correspondence with the light emitting devices, using the generated mask pattern.

An image forming apparatus, including: an image signal generating portion configured to generate an image signal based on image data; a light source configured to emit a light beam based on the image signal; and a deflection device configured to deflect the light beam in a main scanning direction, wherein the image signal generating portion includes: a mode setting portion configured to set a plurality of modes including a mode in which a value of a pixel of the image data is not converted and a mode in which the value of the pixel in one or more lines is converted, to a plurality of areas into which a scanning area is divided in the main scanning direction, respectively; and a pixel value conversion portion configured to convert the value of the pixel in each mode in accordance with a position of the pixel in the main scanning direction.

An image processing apparatus converts, according to light on an image printed based on input image data, the input image data into image data for illumination output superimposed on the image, includes a deriving unit deriving an observing condition, an estimating unit estimating luminance characteristics based on the observing condition and reflectance characteristics corresponding to print image data, an introducing unit introducing target luminance characteristics based on the print luminance characteristics, a setting unit setting illumination converting characteristics converting the input image data into the image data for illumination output based on the print luminance characteristics and the target luminance characteristics, and a converting unit converting gradation of the input image data using the illuminance characteristics, and the introducing unit introducing the target luminance characteristics such that, when reproducing ranges in the print luminance characteristics are different, a linear region of output luminance of relatively large reproducing range becomes larger.