Canon Kabushiki Kaisha

Toshihisa Yago

Naoki Mugita

Katsuya Nose

Fumiyoshi Saito

Yusuke Ishida

Sumito Tanaka

Hiroshi Tomii

Kosuke Takeuchi

A controller controls a charging unit to charge a photosensitive member so that a surface potential of the photosensitive member is controlled to a first potential, controls an exposure unit to expose the photosensitive member so that a potential of an exposure region on the photosensitive member is controlled to a second potential, controls a surface potential of a developing sleeve of a developing unit to a third potential, and forms a test image on a sheet by controlling the photosensitive member, the charging unit, the exposure unit, and the developing unit. An absolute value of the first potential is higher than an absolute value of the second potential. An absolute value of the third potential is higher than the absolute value of the first potential.

Image forming apparatus for detecting fault location

In an image forming apparatus including a reader that can read an original and a printer that can form an image on a sheet based on a read result of the reader, a controller can control the printer to form a test chart on the sheet and control the reader to read the test chart. The test chart is used for detecting a causal part of a streak that occurs when an image is formed by the printer. The test chart has a pattern for obscuring an image defect occurring when the test chart is formed by the printer.

Image forming apparatus for detecting causal part of streak occurring at time of image forming

A controller controls a first image forming unit and a second image forming unit to form a test image having a pattern. The test image is formed by the first image forming unit based on a first image forming condition in which an absolute value of a developing potential of a first developing sleeve is greater than an absolute value of a charging potential of a first photosensitive member. The pattern is formed by a second image forming unit based on a second image forming condition in which an absolute value of a developing potential of a second developing sleeve is smaller than an absolute value of a charging potential of a second photosensitive member. A controller controls a sensor to read the test image having the pattern.

An image forming apparatus includes: an image bearing member, a developing device, and a controller configured to execute an operation in a forced consumption mode. The controller includes a difference calculating portion, an integrating portion, and a flag. In a case where the flag is set when a predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then the controller executes the operation in the forced consumption mode, and in a case where the flag is reset when the predetermined time is elapsed after the integrated value exceeds the predetermined threshold, the image formation on the predetermined number of the recording materials is effected and then the controller continues an image forming operation without executing the operation in the forced consumption mode.

Image forming apparatus

An image forming apparatus capable of controlling density of an output image with high accuracy regardless of variation of internal temperature. A controller controls an image forming unit to form a measurement image, controls a light receiving unit to receive reflected light from the measurement image, controls a conversion unit to convert an output value of the light receiving unit, and controls an image formation condition based on a value that is obtained by converting the output value. An adjustment unit controls the light receiving unit to receive reflected light from an image bearing member, and adjusts the emission light amount of an emission unit based on the reflected light from the image bearing member. A selection unit selects a conversion condition from among conversion conditions based on a reference temperature that is detected when the adjustment unit adjusts the emission light amount and a current temperature.

Image forming apparatus capable of controlling density of output image

A developing apparatus includes a developer bearing member configured to bear and convey a developer containing toner and carrier, a first conveyance screw arranged in a first chamber to convey the developer, a second conveyance screw arranged in the second chamber to convey the developer, and a permeability sensor configured to detect a permeability of the developer. A detection portion of the sensor is arranged below a rotational axis of the second conveyance screw, and a rib portion is formed so as to protrude in a radial direction from a rotation shaft of the second conveyance screw for supplying the developer toward the detection portion.

Developing apparatus having a rib portioned conveyance screw

An image forming apparatus includes an intermediate transfer member bearing a toner image and image forming units arranged side by side, with each image forming unit having a developing device forming the toner image, a magnetic permeability sensor detecting a toner density of a developer in the developing device, and a cleaning unit having a cleaning member which removes toner remaining on an image bearing member and a conductive support member which supports the cleaning member. The apparatus further includes a conductive member facing the magnetic permeability sensor of the most upstream image forming unit and arranged upstream of that image forming unit. The developing device of one of adjacent image forming units is opposed to the cleaning unit of another unit which is arranged downstream and is next to the developing device of the one of the adjacent image forming units.

An image forming apparatus includes a photosensitive member, an exposing unit exposes the photosensitive member to exposure light to form an electrostatic latent image, a developing unit develops the electrostatic latent image to form an image, an intermediate transfer member onto which the image on the photosensitive member is transferred, a measurement unit measures a measurement image on the intermediate transfer member, an adjustment unit adjusts gradation characteristics based on the measurement result of the measurement unit, and correction unit corrects intensity of the exposure light for each of a plurality of positions on the photosensitive member in a scanning direction. the correction unit corrects the intensity based on the correction amount with respect to the intensity corresponding to a predetermined position. the predetermine position corresponds to a position in the scanning direction, at which the measurement image is formed.

Image forming apparatus with correction of exposure light using measurement image

Image forming apparatus with forced consumption mode for toner

A developing device includes a developer carrying member for carrying and feeding a developer, first and second chambers for circulating the developer, and a partition wall. A first feeding member feeds the developer in the first chamber in a first feeding direction, and a second feeding member feeds the developer in the second chamber. The second feeding member includes a shaft, a first helical portion for feeding the developer in a second feeding direction, and a second helical portion for feeding the developer in the first feeding direction. The second helical portion is provided on the shaft and provided downstream of the first helical portion via a region where no helical portion is provided. A rib is provided on a first inner surface of the second chamber, with the rib disposed opposite the region where no helical portion is provided and extending upwardly in a vertical direction.

Developing device having developer regulating rib

A developing unit includes a developing container, a developing sleeve, a developer regulating member, and a magnetic field generating portion. The magnetic field generating portion includes a drawing-up pole and a cut pole. In addition, in a peak-to-peak area, the magnetic field generating portion includes at least one of an Fr flat area in which Fr is substantially constant and an Fr attenuation area in which Fr attenuates toward the cut pole side from the drawing-up pole side, and is configured that F&#x3b8; is oriented toward the same direction as a direction of rotation of the developing sleeve in the entire peak-to-peak area.

Developing unit

An image forming apparatus includes an image bearing member, a developing device, a supplying device, and a controller. The controller can execute a normal supply mode and a forced supply mode on the basis of a difference between a toner supply amount in the normal supply mode and a supply amount of the toner to be supplied to the developing device. In a case where the flag is set when a predetermined time is elapsed after the difference exceeds the predetermined threshold, image formation is effected and then interrupted, and then the controller executes the operation in the forced supply mode, and in a case where the flag is reset when the predetermined time is elapsed after the difference exceeds the predetermined threshold, the image formation is effected and then said controller continues an image forming operation without executing the operation in the forced supply mode.

Image forming apparatus with forced supply mode for forcedly supplying toner

A developing device includes a developer carrying member, a first chamber, a second chamber, a first feeding member, and a second feeding member. The second feeding member includes first to third spiral portions and a disk portion. The disk portion includes a projected portion. When the disk portion is seen in an axial direction of the second feeding member, on the basis of a line connecting a rotation center of the disk portion and an upstream end portion of the third spiral portion with respect to a feeding direction of the third spiral portion, the projected portion is provided within a range from a position deviated by 90 degrees toward a downstream side with respect to a rotational direction of the disk portion to a position deviated by 30 degrees toward an upstream side with respect to the rotational direction of the disk portion.

Developing device

An image forming apparatus includes an image forming unit including a containing unit that contains a developer including toner and forms an image based on image data by using the toner, a supply unit that supplies the toner into the containing unit, a consumption amount calculation unit that calculates, based on information related to a density of an image corresponding to the image data, a consumption amount in the containing unit, a detection unit that detects a toner density of the developer in the containing unit, a correction amount calculation unit that calculates, based on the information and the toner density detected by the detection unit, a correction amount by which the consumption amount is corrected, and a controller that controls the supply unit based on the consumption amount and the correction amount calculated by the correction amount calculation unit.

Image forming apparatus supplying toner based on toner density of developer contained in containing unit and method for controlling image forming apparatus

A controller for an image forming apparatus includes a difference calculating portion for calculating a difference between a consumption value depending on an amount of the toner consumed every predetermined unit and a reference value; and a difference integrating portion. When an integrated value of the difference is larger than a predetermined threshold, the controller executes an operation in a forced consumption mode so that the toner is consumed in an amount corresponding to a predetermined value obtained by multiplying the predetermined threshold by a coefficient of less than 1. When the operation is executed, the integrating portion sets, at a reset value, a value obtained by subtracting the predetermined value from the integrated value at that time. After the operation is executed, the controller executes the operation every time when an integrated value obtained by integrating the reset value and the difference is larger than the predetermined threshold.

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Toride, Japan

Toshihisa Yago