Sharp Kabushiki Kaisha Corporation

Takashi Kitagawa

Katsuhiro Nagayama

Masayuki Otsuka

Toshiaki Ino

Kiyofumi Morimoto

Mitsuru Tokuyama

Yasuhiro Nishimura

Yasutaka Maeda

Eiichi Kido

Takayuki Yamanaka

Tatsuya Tanaka

Makoto Uehara

Kaori Dakeshita

Toshihiro Ohta

Hiroshi Kawano

Kyosuke Taka

Toshio Yamanaka

Masatsugu Nakamura

Hideaki Kadowaki

Motoyuki Itoyama

Daisaku Imaizumi

Masayasu Narimatsu

Hiroshi Kawamoto

Mitsuyoshi Terada

Masaaki Ohtsuki

Ginga Nakamura

Shinji Imagawa

Ken Yamagishi

Masaya Fujitani

Norihide Yasuoka

Kaori Fujii

Yuka Sakagami

Shouji Tomita

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.

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 pixel count section calculates a coverage rate corresponding to toner consumption. A control coefficient value setting section determines, based on the coverage rate, a stop threshold value representing reference concentration for toner replenishment and replenishment extension time. A magnetic permeability sensor measures permeability representing toner concentration in a housing portion. A toner concentration control section starts toner replenishment when an output value from the magnetic permeability sensor varies from a value less than a start threshold value to the start threshold value or above, and stops toner replenishment after lapse of replenishment extension time from the time at which an output value varied from a value greater than the stop threshold value to the stop threshold value.

Toner replenishing method, toner replenishing apparatus, and computer readable recording medium

A small domain generation section generates a plurality of small domains in a multi-valued image transmitted from an intermediate tone correction section. Each domain is constituted of a plurality of pixels. Counting means counts a signal input value of each pixel. Weighting calculation means corrects each signal input value of the 'pixels subjection to toner quantity equivalent value calculation' with reference to the signal input value of the small domain, and reads out a weighting coefficient from the weighting coefficient table based on the modified signal input value. The weighting calculation means multiplies the signal input value by the coefficient so as to convert the signal input value into a toner quantity equivalent value. Accumulating means calculates toner quantity equivalent values for all of the pixels of the multi-valued image. A total toner quantity equivalent value calculation section determines a total toner quantity equivalent value by accumulating all of the toner quantity equivalent values which are individually calculated each time an image is processed. When the total toner quantity equivalent value reaches a predetermined value, conditions for process control is set. On this account, the present invention achieves an image forming apparatus capable of accurate estimation of toner consumption quantity.

Image forming electrophotography apparatus setting conditions for process control based on a total toner quantity equivalent value

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.

Image forming apparatus and toner supply control program for the same

The image forming apparatus according to the present invention carries out intake and exhaust so as to generate air flow between a photoconductor drum and a charger in a long side direction of the charger. As a result, it is possible to always exhaust O, NOx, and the like caused by corona discharge. Therefore, it is possible to always form a high-quality image without deterioration of images caused by charge unevenness.

Image forming apparatus including a charger and intake/exhaust

In an optical discharge apparatus used in an electrographic image forming apparatus, by forming, on a light guiding member, a diffusing reflecting face for reflecting light from an LED lamp towards a photosensitive drum, and by supplementing the amount of light by altering the height of the diffusing reflecting face to the light emitting face and the width of the diffusing reflecting face in accordance with their distance from the light source, the light intensity distribution of the irradiating light that is irradiated onto the photosensitive drum is made uniform. An optical discharge apparatus may include a light guiding member arranged facing a photoreceptor; and a light source, a diffusing reflecting face for reflecting the light from the light source toward the photoreceptor is formed on the light guiding member, and a reflecting member is arranged on an upper face in the vicinity of an end portion of the light guiding member.

Optical discharge apparatus and image forming apparatus containing the same

An image forming apparatus is arranged such that one reference test pattern image expressed in a tone expression is formed on the predetermined image bearing member, the tone expression being different from a tone expression of an image formed in the print modes that carry out a normal print process, and density of the formed reference test pattern image is detected, and subsequently sets of density correction data for the print modes are created based upon the detected density.

Image forming apparatus and density correction data creation method used therein

One embodiment of an image correction method is an image correction method for correcting image forming condition(s). The image correction method includes forming, on photoreceptor(s), correction test pattern(s) having continuously varying toner gradation; wherein a single correction test pattern in which density is varied in sequence from high to low in paper transport direction(s) is formed as a result of controlling exposing unit laser power(s) while photoreceptor charging potential(s) is/are held constant, or while develop bias(es) is/are held constant, or while photoreceptor charging potential(s) is/are held constant and develop bias(es) is/are held constant. In such case, total length(s) in paper transport direction(s) of such correction test pattern(s) is/are less than or equal to circumference(s) of photoreceptor(s).

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Nara, Japan

Takashi Kitagawa