Sharp Kabushiki Kaisha Corporation

Katsuhiro Nagayama

Yasutaka Maeda

Takashi Kitagawa

Hideyuki Nishimura

Masayuki Otsuka

Natsuko Tanaka

Taisuke Kamimura

Tsuyoshi Miyamoto

Toshihiro Ohta

Kunio Ohashi

Masatsugu Nakamura

Jitsuo Masuda

Toshihisa Ishida

Hideji Saiko

Tadashi Tonegawa

Yuichi Kazaki

Makoto Uehara

Kazuki Wakita

Fumio Shimazu

Kazuyuki Ohnishi

Yoichi Shimazawa

Hideo Matsuda

Toshiaki Ino

Takashi Usui

Hiroo Naoi

Motoyuki Itoyama

Daisaku Imaizumi

Masayasu Narimatsu

Tatsuya Tanaka

Syoichi Nagata

Shoichi Nagata

Hiroshi Kawamoto

Katsuaki Sumida

Koichi Moriyama

Tomoko Nishino

Kiyoto Motoyama

Norihide Yasuoka

Masaya Fujitani

Kaori Dakeshita

Tuyoshi Miyamoto

Koji Shinkawa

Shouichi Fujita

Kiyoshi Takato

Shouji Tomita

An image processing unit includes a region separation device and a spatial filtering device. The region separation device detects line widths of a manuscript image in which the line widths are different between a vertical line and a horizontal line and determines which of the vertical line or the horizontal line is thinner. The spatial filtering device executes an emphasizing process to make a widening ratio of a thinner line of the vertical line or the horizontal line higher than a widening ratio of the other line.

Image processing unit, image forming apparatus, image processing method, and storage medium

An image forming apparatus includes image forming sections for respective colors, the image forming sections facing an outer surface of an intermediate transfer belt on an outward path. A transfer roller is provided on a returning path and is movable to a contact position where the transfer roller is pressed against the intermediate transfer belt or to a detachment position where the transfer roller is detached from the intermediate transfer belt. A density sensor is provided for detecting a density of toner image on the intermediate transfer belt. In an image quality adjustment operation, image forming sections form a toner image row on the intermediate transfer belt, and the density sensor measures densities. A length of the toner image row is smaller than a length of the intermediate transfer belt between the endmost photoreceptor drum on the downstream side and the transfer roller.

High speed image forming apparatus and image forming method thereof

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.

Image forming apparatus and image forming method

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

An image forming apparatus, an image forming method, a program, and a recording medium that succeed in reducing recording agent consumption without causing image quality degradation are provided. A modification region processing section detects, out of image data, A locations where a region identification signal provided from a region separation processing section changes from a ground region mode to a character region mode, and vice versa, as the boundary between the ground region and the character region, and thereby specifies a modification region which is continuous with the ground region and overlaps with a part of a periphery of the character region which is contiguous to the ground region. The modification region is assigned color data indicating a color that can be represented by the recording agent for use in ground region formation thereby to generate image data.

Image forming apparatus, image forming method, program, and recording medium

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

An object of the present invention is to obtain, in an accurate and stable manner, an image density at a tone rise point in a low-density region in order to form a stable image. At the time of execution of an image density correction in an image forming apparatus which employs an electrophotographic process, a toner pattern of a plurality of toner patches is formed on the basis of a reference density correction table which specifies an image density output value used for correction of an image density input value, the density of the toner patches is detected by a density detecting sensor, points corresponding to a plurality of image densities in a low-density region, detected above a predetermined level of sensitivity of the sensor, are plotted thereby to find a linear interpolation formula, an image density in the low-density region below the predetermined level of sensitivity of the density detecting sensor is interpolated with the linear interpolation formula, a comparison between the reference density correction table and a result of the interpolation is made so as to correct the image density output value, and a correction table as a post-modification correction table is prepared. An actual image is prepared using the correction table.

A high density detecting toner pattern is formed on a photosensitive body and a high density correction is effected by comparing a value detected by a reflection sensor with a high density reference value so as to maintain an image density at a specific level. An image density correcting section adopts a result of the preceding high density correction as the high density reference value, and compares the same with a result of a current high density correction. The image density correcting section effects the half-tone density correction only when a difference reaches or exceeds a preset difference reference value by forming a half-tone density detecting toner pattern on the photosensitive body and comparing a value detected by the reflection sensor with a half-tone reference value. Consequently, it has become possible to provide an image forming apparatus which can maintain a density output of an entire image at a specific level for any kind of images including solid, line, and half-tone, etc. while shortening a time required for the density correction and reducing a quantity of toner consumed for the density correction.

Image forming apparatus with half-tone density control

An image forming apparatus in which each test image formed in a plurality of image forming sections is transferred onto a transfer carrier belt by transfer means respectively provided corresponding to the plurality of image forming sections, and the transfer state is detected to control the image forming conditions, wherein the transfer condition of the respective transfer means is different when the test image is transferred onto the transfer medium and when the test images already formed and transferred in other image forming sections pass through the transfer means.

A test patch image is formed and the density thereof is detected to maintain the image quality at a constant level. One of the image forming conditions, for example, the developing bias voltage of the developing unit inside the image forming apparatus that serves as a density controller, and is controlled in accordance with the detection result. Here, a humidity sensor for detecting the environmental change, that is, the humidity, is provided inside the apparatus, and the reference value of the toner mixing ratio is changed and corrected while the developing unit is operating when the humidity sensor detects a change in humidity. However, the toner mixing ratio is maintained and neither changed nor corrected when the density of the test patch image remains at the same level, so that the developing bias voltage is not corrected. Consequently, the correction of the toner mixing ratio is neither changed nor corrected in response to the change in humidity alone, thereby making it possible to maintain a stable image quality state.

Image forming apparatus including image quality compensation means

The static latent image formed on the photoreceptor which has been charged, by exposing it to light, is developed through four colors of developing units, i.e., yellow, magenta, cyan and black, forming toner images on the photoreceptor. These toner images are transferred to the transfer drum. Before forming the toner images, a device is provided to correct the measurement value of toner density obtained using the light emitter and photosensor into an exact value. Based on the reflected light from a white-coated area formed on the transfer drum, two levels of the intensities of emitted light are determined. The intensity of received light is compared to the standard value so that the output value from the photosensor corresponding to the toner density is made to approximate the standard value.

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Nara, Japan

Katsuhiro Nagayama