A color test pattern comprising color patches can be printed together with an image (text and/or a pictures, for example) of a print job. After printing, reflections, known as flare, from the image may adversely affect measurements taken of the color patches. To help reduce the effects of flare, a determination is made prior to printing as to the layout of the color patches. The determination involves comparing the color properties of the color patches with those of the image.

An image forming apparatus include a latent image bearer, charger, latent image forming unit, developing unit, receiver unit, transfer unit, information acquisition unit, and correction unit. The charger charges the latent image bearer with a predetermined charging potential. The latent image forming unit forms an electrostatic latent image on the latent image bearer. The developing unit develops the electrostatic latent image to form a toner image. The receiver unit receives the toner image from the talent image bearer. The transfer unit applies a predetermined transfer bias to transfer the toner image to the receiver unit. The information acquisition unit acquires residual image generation determination information. When predetermined residual image generation condition is satisfied, a correction unit corrects image forming condition such that surface potential unevenness of the latent image bearer subsequent to transfer is smaller than that generated where predetermined residual image generation condition is not satisfied.

An image forming apparatus includes: a photoconductor drum; an optical scanner, having a light source, configured to scan the photoconductor drum with light to form a latent image; a developer configured to develop an image, based on the latent image; a cycle detector configured to detect a rotation cycle of the photoconductor drum, to produce a cyclic signal indicative of the rotation cycle; a density detector configured to detect density of the image; a measurer configured to measure the rotation cycle at each rotation, based on the cyclic signal; a generator configured to generate, based on the density, a correcting value for correcting intensity of the light, the correcting value having a correction cycle based on a measurement result of the measurer; and an adjuster configured to adjust the correction cycle based on the rotation cycle measured at each rotation, so that the correction cycle matches the rotation cycle.

An image forming apparatus includes a light-receiving unit that includes light-receiving elements arranged along a movement direction of a target formed on an image carrier, and is arranged so as to receive light emitted from a light-emitting unit and specularly reflected off the image carrier; a member configured to limit a size, in the movement direction, of diffused reflection light that is incident on the light-receiving unit; a selection unit configured to select whether or not each of the light-receiving elements in the light-receiving unit is an effective light-receiving element; a generation unit configured to generate a detection signal from an output of the effective light-receiving element; and a detection unit configured to detect a target formed on the image carrier based on the detection signal.

A sensor includes a light emitter and a photodetector. The light emitter outputs light with which a toner pattern or a surface material of an image carrier is irradiated. The photodetector receives reflection light from the toner pattern or the surface material. The sensor light intensity control unit provides a control voltage to the light emitter and thereby controls light intensity of the light emitter. The density determining unit determines a toner density on the basis of output of the photodetector. Further, the density determining unit (a) determines as a correction parameter a first-order coefficient of the control voltage of the light emitter for an output voltage of the photodetector corresponding to reflection light from the surface material, (b) determines a correction amount corresponding to the correction parameter and the toner density, and (c) corrects the toner density on the basis of the correction amount.

A color test pattern comprising color patches can be printed together with an image (text and/or a pictures, for example) of a print job. After printing, reflections, known as flare, from the image may adversely affect measurements taken of the color patches. To help reduce the effects of flare, a determination is made prior to printing as to the layout of the color patches. The determination involves comparing the color properties of the color patches with those of the image.

An image forming apparatus includes a light-receiving unit that includes light-receiving elements arranged along a movement direction of a target formed on an image carrier, and is arranged so as to receive light emitted from a light-emitting unit and specularly reflected off the image carrier; a member configured to limit a size, in the movement direction, of diffused reflection light that is incident on the light-receiving unit; a selection unit configured to select whether or not each of the light-receiving elements in the light-receiving unit is an effective light-receiving element; a generation unit configured to generate a detection signal from an output of the effective light-receiving element; and a detection unit configured to detect a target formed on the image carrier based on the detection signal.

Provided is an image formation device including a photoreceptor configured to carry a toner image and a developer configured to form the toner image on a surface of the photoreceptor and configured such that the developer is a replaceable development unit, the image formation device including: a development bias application section configured to apply a development bias to between the photoreceptor and the developer; a stabilization control section configured to perform image stabilization control of determining a development bias value to be used in future by changing the development bias while measuring a density of the toner image formed by the developer, thereby obtaining the toner image with a target density; and a life determination section configured to determine expiration of use of the development unit when the development bias value determined by the stabilization control falls outside a preset acceptable range.

An image forming apparatus includes a photoreceptor, an exposure unit, a developing unit, and a control unit. The control unit sets the toner-layer-forming electric potential difference lower than an electric potential when forming the image on the print medium, forms a combined patch for calibration by the set toner-layer-forming electric potential difference for calibration, so as to adjust the developing-bias potential by measuring a print density of the formed combined patch. The combined patch includes a first patch and a plurality of second patches. The plurality of second patches have a width within a range of 0.2 mm to the predetermined value in the peripheral-velocity direction of the photoreceptor, extend with a length equal to or more than the predetermined value in the rotation-shaft direction of the photoreceptor, and are arranged at a predetermined interval in the peripheral-velocity direction of the photoreceptor.

An image forming apparatus includes an image forming device, an image density detector, and an output change device configured to cause the image forming device to form a test toner image while cyclically changing a charging power based on a charging change pattern and a developing bias based on a developing change pattern, generate an image density fluctuation pattern of the test toner image in a rotation direction of a latent image bearer, generate a writing change pattern to cyclically change a power of latent image writing based on the image density fluctuation pattern of the test toner image and one of the charging change pattern and a correlative pattern correlated with the charging change pattern. The output change device is configured to cyclically change the power of latent image writing based on the writing change pattern during image formation according to a user command.