Sharp Kabushiki Kaisha Corporation

Masayuki Otsuka

Takashi Kitagawa

Katsuhiro Nagayama

Motoyuki Itoyama

Tatsuya Tanaka

Ginga Nakamura

Masaya Fujitani

Norihide Yasuoka

An image forming apparatus according to this disclosure includes: a charging roller that charges a surface of a photoconductor drum; a development unit that forms a toner image on the surface of the photoconductor drum; an image density sensor that detects density of the formed toner image; a charge power supply that applies a bias voltage to the charging roller; a development power supply that applies a bias voltage to the development unit; and a controller. The controller causes the charge and development power supplies to output respective predetermined bias voltages for predetermined time, and is capable of executing a contact and separation determination mode in which a contact and separation state of the charging roller is determined based on whether or not an image is detected by the image density sensor after output of the respective bias voltages.

Image forming apparatus provided with charging roller

An image forming apparatus includes: a roller arranged in a position between a drive roller and an idle roller and downstream from the drive roller in a rotation direction of an intermediate transfer belt while pressing an outer surface of the belt; and a density measuring portion arranged between the drive roller and the roller applying pressure. The density measuring portion optically detects the density of a test patch formed on the outer surface and in a given position of a width direction of the belt. The density measuring portion includes: an optical sensor provided above the outer surface of the belt; and a support member abutting on an inner surface of the belt in a position in which the support member faces the optical sensor across the belt in the rotation direction.

Image forming apparatus with density measuring portion

An image forming apparatus includes a photoreceptor, a developing apparatus, a developing bias supply power source, a control section for controlling a developing bias, a density sensor, and an arithmetic section. When an image density adjustment operation is performed, the arithmetic section determines a print-time developing bias in accordance with a detection result obtained by detecting, by the density sensor, a plurality of image density adjustment toner images formed by changing a developing bias. The print-time developing bias is set by the control section when printing is performed. also, In a case where a previous print-time developing bias falls within at least a low range of a predetermined range of the developing bias, the arithmetic section determines the print-time developing bias to a value between a reference developing bias for a target image density and the previous print-time developing bias.

Image forming apparatus and image forming method

An image processing section includes a density correction adjustment section, and in response to an instruction from a density correction process section to adjust a density correction process, the density correction adjustment section reviews a conversion value table which is used by the density correction process section to calculate an output correction value by conversion, so as to adjust the density correction process.

Image processing apparatus and image forming apparatus with a toner density correction function

An image forming apparatus including: a black image forming section for forming a black image and a first black pattern for a coarse correction of black and optionally a second black pattern for a precise correction of black; a color image forming section for forming a color image optionally a third pattern for a coarse correction of color and optionally a fourth pattern for a precise correction of color; and a control section for allowing at least the first black pattern to be formed and optionally a second black pattern and third and fourth color patterns, and controlling to perform the coarse correction of black for correcting a forming condition of a black image to be formed and to perform optionally a precise correction of black, the coarse and precise correction of color based on the measurement of the formed pattern(s), wherein the control section controls to perform the coarse correction of black but not to perform the precise correction of black and the coarse and precise corrections of color in case a print job is acquired after a predetermined period elapses since the black image forming section has formed the first black pattern previously and the acquired print job includes a black-and-white page only.

When an image forming job is completed that records onto a recording sheet an image formed on a photoconductor drum and conveys the recording sheet, a simple process control is carried out that forms some filled patch images with using some toners. After the simple process control is carried out, a determination is carried out, in accordance with a charge control value of a charge roller adjusted by the simple process control (a voltage value applied on the charge roller), whether a formal process control should be carried out or not that forms many patch images with using much toners. The formal process control is additionally carried out, when the determination means so.

Image quality adjustment method, image forming apparatus and computer readable medium

It is judged whether a sufficient time for executing all of three correction processings (a high density correction processing, a halftone correction processing, and a registration correction processing) can be secured or not. When the sufficient time cannot be secured, the high density correction processing as an essential correction processing is executed. A history of the halftone correction processing and a history of the registration correction processing are compared with each other. A date of latest execution of the halftone correction processing and a date of latest execution of the registration correction processing are compared with each other to judge whether or not the execution of the halftone correction processing is earlier, and the registration correction processing and the halftone correction processing are executed, respectively.

An image forming apparatus and an image forming method capable of executing process control at appropriate timing are provided. A control section of an image forming apparatus carries out control for determining execution time of process control and executing the process control. The control section includes a counting section, a determining section and a process control management section. The counting section counts a number of printed sheets. The determining section determines on what time process control is to be executed form the counted number of printed sheets for each time zone. The process control management section manages the process control executed at an image forming section with the whole of the image forming apparatus.

Image forming apparatus and image forming method for suppressing fluctuation of formed images

Related is an image forming apparatus by electrophotography having a function of performing adjustment of image quality when performing image formation. The image forming apparatus includes a detection portion for detecting a fixing temperature of a fixing apparatus; a storage portion for storing an application history of a development bias; a count portion for counting a reposed time from a point when an operation of image formation is ended; a determination portion for determining a change range of the development bias immediately before the end of the operation of image formation; and an execution portion for executing adjustment of image quality by setting the development bias based on a determination result from the determination portion when the reposed time or the fixing temperature exceeds a predetermined value.

Image forming apparatus and method for controlling image forming apparatus

An image forming apparatus includes: an image forming section; a manual setting mode for enabling a user to provide instruction of timing for executing a process control of the image forming section; a cumulative operation information management section for calculating and storing cumulative operation information after the execution of the previous process control; a threshold value setting section for setting, to a threshold value, the cumulative operation information at the point when the instruction is provided in the manual setting mode; and a process control management section for executing a process control and resetting the cumulative operation information at timing when the cumulative operation information reaches the threshold value.

Image forming apparatus

A digital color copier includes: a toner concentration storage which stores a detected toner concentration of each developer block of multiple developer blocks across an image forming width; a toner consumption predictor for predicting a first predicted toner consumption of toner consumed from developer of every developer block during a first circulation; a toner concentration estimator for estimating, for every developer block, a toner supply point estimate as the toner concentration at a point where toner is supplied, by subtracting the first predicted toner consumption from the associated detected toner concentration and setting up a toner supply target value of the toner to be supplied from a toner supply device to a developing device in accordance with the predicted toner consumption during a second circulation of the developer inside the developing device that follows the first circulation.

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Osaka, Japan

Masayuki Otsuka