Ricoh Company, Ltd.

Terumichi Ochi

Shuji Hirai

Satoshi Kaneko

Shinji Kato

Ryota Yamashina

Takumi Waida

Yuuichiroh Uematsu

Keitaro Shoji

Naoto Watanabe

Shinichi Namekata

Muneaki Iwata

Motoyoshi Yamano

Hideo Muroi

An image forming apparatus includes a latent image bearer, a charger to charge the latent image bearer with a charging bias obtained by superimposing a charge fluctuation voltage to reduce an image density fluctuation on a direct current charging voltage, a writing device to write a latent image on the latent image bearer with writing intensity obtained by superimposing fluctuating writing intensity to reduce an image density fluctuation on constant writing intensity, a developing sleeve to which a developing bias obtained by superimposing a fluctuating developing voltage to reduce an image density fluctuation on a direct current developing voltage is applied to develop the latent image, and circuitry to control the charging bias, the writing intensity, and the developing bias. The circuitry changes the charge fluctuation voltage and the fluctuating developing voltage depending on whether the writing device writes the latent image with the fluctuating writing intensity.

Image forming apparatus

An image forming apparatus includes a latent image bearer; a writing device configured to write a latent image onto the latent image bearer; a detection device configured to detect, at a plurality of positions, a density of a toner image obtained through development of the latent image; and a controller configured to correct a writing intensity of the writing device to correct an uneven density based on detection values of the detection device. The controller determines whether each of the detection values is pass or fail. In response to a determination that a detection value is fail, the controller corrects the wiring intensity based on another detection value determined to be pass at a position different from a position at which the detection value is determined to be fail, instead of correcting the writing intensity based on the detection value determined to be fail.

An image forming apparatus includes an image forming unit and a controller. The image forming unit includes a latent image bearer, a charger to charge the latent image bearer, an exposure device to expose a latent image on the surface of the latent image bearer, and a developing device to develop the latent image with a developer. The controller executes an image forming process, a first fluctuation control that cyclically changes a developing bias supplied to the developing device based on predetermined first pattern data, and a second fluctuation control that cyclically changes a charging bias supplied to the charger based on predetermined second pattern data, in parallel. The controller executes a determination process to determine whether the controller executes the first fluctuation control. When the controller determines not to execute the first fluctuation control, the controller determines not to execute the second fluctuation control, too.

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.

Image forming apparatus and image forming method which cyclically change a charging power and a developing bias applied to a developer bearer

An image forming apparatus includes an image forming section that includes a latent image bearer; a charger to charge a surface of the latent image bearer; and a latent image writer to write a latent image on the charged surface of the latent image bearer. The image forming apparatus further includes a developing device to develop the latent image with a developer borne on a developer bearer; and a cyclical changing device including a controller and a write controller, in combination. The cyclical changing device cyclically changes a developing bias to be applied to the developer bearer while cyclically changing a charge intensity of the charger during the image formation by the image forming section. The cyclical changing device cyclically changes the developing bias and the charge intensity, and a latent image write intensity of the latent image writer.

An image forming apparatus includes an image forming device, an electric current detector, and a controller. The image forming device includes a latent image bearer, a charging rotator, a charging power supply, a latent image writing unit, and a developing unit. The controller (i) determines an uneven electric resistance of the charging rotator in a direction of rotation of the charging rotator, based on a detection result by the electric current detector, (ii) perform, at a predetermined timing, data construction processing to construct change pattern data to change an output value of a voltage from the charging power supply according to a predetermined pattern, based on the uneven electric resistance, and (iii) perform, in a print job to form a toner image in response to an instruction, voltage changing processing to charge the latent image bearer while changing the output value of the voltage, based on the change pattern data.

Technique for reducing uneven image density in an image forming apparatus

An image forming apparatus includes: a latent image forming unit that forms a latent image on a latent image bearer with light from a light source; and a correction data generating unit that includes: an acquiring unit that acquires, for each position, a correction value of an intensity of the light source to equalize a density distribution of a latent image; a quantizing unit that generates a correction data for each position by quantizing a correction value for each position; and an excessive correction suppressing unit that outputs the correction data after reducing an amount of change from an immediately preceding latent image formation position, with respect to a position at which an absolute value of a restored value indicating a correction amount and generated based on the correction data exceeds an absolute value of the correction value.

Image forming apparatus and correction data generation method which corrects the intensity of a light source which forms a latent image

A recording media smoothness detector includes a sensor and a calculator. The sensor includes a light source to emit light toward a recording medium and a light detector to detect an amount of light reflected by the recording medium. The calculator includes a first memory to store an initial output value of the sensor and a second memory to store a decreased output percentage of the sensor relative to the initial output value per number of recording media detected. The calculator is configured to calculate a decreased output amount of the sensor from the decreased output percentage of the sensor per number of recording media detected, according to a number of recording media detected by the sensor, to adjust a luminosity of the light source based on the calculated decreased output amount of the sensor and determine a type of the recording medium based on an output of the sensor after the adjustment of the luminosity of the light source and based on the number of recording media detected by the sensor.

Recording media smoothness detector and image forming apparatus incorporating same

An image forming apparatus includes paper trays to contain and feed a recording sheet on which a toner image is transferred; status sensors to detect a storage status of the recording sheet contained in the paper trays; a sheet sensor to detect a smoothness of the recording sheet; a memory to store detection values of the smoothness detected by the sheet sensor; a fixing device to heat and press the toner image transferred onto the recording sheet and fix it onto the recording sheet; and a control circuit to determine a target fixing temperature of the fixing device based on the detection values stored in the memory. The control circuit determines the target fixing temperature for successive recording sheets depending on the detected smoothness, and resets the detection values stored in the memory to zero when the status sensors detect a change in the storage status of the paper trays.

An image forming apparatus includes a latent image bearer, a toner image forming unit, and a transfer device. The toner image forming unit includes a charger, a latent image forming device, and a developing device, and is configured to form a test latent image pattern on a surface of the latent image bearer, and to develop the test latent image pattern into a test toner pattern. The test latent image pattern includes a plurality of test latent image parts partly offset from one another in a main scanning direction. The image forming apparatus also includes a developing current detector and a processor to detect uneven image density in the main scanning direction using the test latent image pattern, based on the developing current detected by the developing current detector, to adjust the uneven image density in the main scanning direction.

Image forming apparatus forming a plurality of displaced test latent image parts

An image forming apparatus includes a storage to store recording media, a smoothness detector to detect smoothness of the recording media, a memory unit to store smoothness values detected by the smoothness detector, a transfer device to transfer a toner image onto the recording media, a fixing device to fix the toner image onto the recording media, a temperature controller to determine a target fixing temperature for a second and subsequent recording media based on a predicted value calculated from the smoothness values, and a processor to reset the smoothness values in response to detection of an external factor that causes the smoothness detector to provide a smoothness value out of a predetermined range of the predicted value during an image forming operation from when the processor receives a sheet-feeding permission signal of one of the recording media stored in the storage until the recording medium is ejected.

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Kanagawa, Japan

Terumichi Ochi