Canon Kabushiki Kaisha

Akihiro Noguchi

Fumitake Hirobe

Tadayoshi Nishihama

Katsuya Nose

Tatsuomi Murayama

Akinori Tanaka

Tadashi Fukuda

Kota Arimoto

Kyosuke Takahashi

Shigeru Tanaka

Haruhiko Omata

Yuichiro Toyohara

Asuna Fukamachi

Mitsuhiro Furukawa

Yasuki Kamimori

Motohiro Fujiwara

Satoru Stephen Yamauchi

Hideki Fujita

Kosuke Takeuchi

Yuji Ohkubo

An image forming apparatus includes an image forming unit, an image heating device, a filter, a display unit, and a controller. When an image forming operation of the image forming unit starts and an ambient temperature outside the image forming apparatus is a first temperature, the controller sets, after the image forming operation starts, a first period that begins after detected ambient temperature inside the image forming apparatus reaches a predetermined temperature and ends when filter replacement information is displayed on the display unit. When the image forming operation starts and the outside ambient temperature is a second temperature higher than the first temperature, the controller sets, after the image forming operation starts, a second period that is shorter than the first period and begins after the detected inside ambient temperature reaches the predetermined temperature and ends when the filter replacement information is displayed on the display unit.

Image forming apparatus

An image forming apparatus includes a controller to control a driving device such that a rotational speed of a supplying and feeding screw when it is rotated a predetermined number of times to supply developer to a developing device in a predetermined amount during execution of a continuous image forming job on a plurality of first recording materials is a first rotational speed, and a rotational speed of the supplying and feeding screw when it is rotated the predetermined number of times to supply the developer in the predetermined amount during execution of a continuous image forming job on a plurality of second recording materials is a second rotational speed slower than the first rotational speed. The second recording materials have a length longer than the first recording materials with respect to a sub-scan direction.

An image forming apparatus includes an intermediary transfer member, a toner image forming unit, a rotatable transfer member, a cleaning unit, a feeding unit, a feeding portion and an executing portion configured to execute a supplying operation for supplying a supplying toner image to a cleaning portion. The executing portion forms the supplying toner image at a position including a position different from a position where an adjusting toner image for adjusting an image forming condition is formed, with respect to a widthwise direction crossing a movement direction of an intermediary transfer member provided in contact with the rotatable transfer member. The executing portion performs the supplying operation at least one time in a double-sided image forming job and does not perform the supplying operation in a single-sided image forming job.

A magnet roller employs a magnetic pole pattern in which a first magnetic pole arranged substantially opposing a regulating blade in an upstream side of a rotation direction of a developing sleeve and a second magnetic pole next to the first magnetic pole in the upstream side have the same polarity, an opposing member having surface roughness higher than at least a particle diameter of carrier is arranged opposing the magnet roller at a position where magnetic force between the first magnetic pole and the second magnetic pole next to the first magnetic pole in the upstream side is almost zero, and an apex of a partition wall provided between a developer bearing member and a developer conveying member provided in a first chamber is positioned below a region where magnetic force formed by the magnet roller is almost zero.

Developing device for preventing density unevenness and developer overflow

An image forming apparatus includes a movable intermediary transfer member, a toner image forming unit, a rotatable transfer member, a fixing unit, a recording material feeding portion, an executing portion, and first and second cleaning units. The first cleaning unit includes a first brush roller, a first rotatable member and a first blade member. The second cleaning unit includes a second brush roller, a second rotatable member, a second blade member and a third blade member. The third blade member is disposed downstream of the cleaning portion and upstream of a contact portion, between the second rotatable member and the second brush roller, with respect to a rotational direction of the second rotatable member, and scrapes a deposited matter off the second rotatable member with the rotation of the second rotatable member.

A multipolar magnet is arranged inside a developer bearing member. A partitioning wall is arranged such that an apex position thereof is located between the developer bearing member and a first conveying member, and is extended up to a position which is located below an upper end position of a zone. A plurality of concaved portions is formed on the surface of the developer bearing member at an interval. Each of the plurality of concaved portions has such an opening shape that a maximum diameter of an inscribed circle is equal to or greater than a diameter of an average grain size of a carrier, and is formed such that the carrier with the average grain size is able to enter each of the concaved portions by a depth that is equal to or greater than a radius thereof.

Developing unit

Precise correction of a position of a toner image formed by an image forming station can be accomplished in a device using two-component developer. An electrostatic latent image for forming a color misregistration correction pattern for color misregistration correcting includes a first latent image pattern and a second latent image pattern at a position downstream of the first latent image pattern with respect to the moving direction of the electrostatic latent image. The toner image resulting from the development of the first latent image pattern has a width, measured in the image moving direction, which is greater than that of the toner image resulting from the development of a latent image pattern alone, which is the same as the first latent image pattern, or the toner image resulting from the development of the first latent image pattern has an image density at a downstream end portion with respect to the moving direction, which density is higher than that of the toner image resulting from the development of the latent image pattern alone, which is the same as the first latent image pattern.

Image forming apparatus operable in writing position correction mode

A controller controls a replenishing operation of the first replenishing device based on the first sensor, and controls a replenishing operation of the second replenishing device based on the second sensor. The controller prohibits the replenishing operation of the first replenishing device when the developer concentration in the first replenishing device reaches a first upper limit set to the first developing device, and the controller prohibits the replenishing operation of the second replenishing device when the developer concentration in the second replenishing device reaches a second upper limit set to the second developing device. The controller corrects the second upper limit based on the developer concentration in the second developing device when the developer concentration in the first developing device reaches the first upper limit.

A developing device includes a developing sleeve for carrying a developer for developing an electrostatic latent image formed on an image bearing member, a magnet for carrying the developer on the sleeve, and a regulating member for regulating an amount of the developer carried on the sleeve. Magnetic poles of the magnet are disposed so that a circumferential direction component of a magnetic force acting on a magnetic carrier of the developer contacting at least a part of an upstream regulating surface of the regulating member with respect to the direction of rotation of the sleeve is opposite from the direction of the rotation.

Developing device

A developing device includes a developer carrying member for carrying developer containing a non-magnetic toner and a magnetic carrier to a position where the developer carrying member is opposed to an image bearing member, and a developing container including a first chamber for accommodating the developer to be supplied to the developer carrying member, a second chamber provided below the first chamber, and an opening for circulating the developer between the first chamber and the second chamber. In addition, a first feeding member and a second feeding member are rotatably provided in the first chamber and the second chamber, respectively, for stirring and feeding the developer. A first magnet member of the first feeding member and a second magnet member of the second feeding member are provided so that same magnetic polarity portions are opposed to each other or so that a ratio of a range in which the same magnetic polarity portions are opposed to each other is greater than a ratio of a range in which opposite magnetic polarity portions are opposed to each other.

Developing device having dual feeding chambers

A magnetic flux density formed on a sleeve surface by a magnetic seal member on a downstream side in a conveyance direction of a developer agitation and conveyance member is greater than a magnetic flux density formed on the sleeve surface by a magnetic seal member on an upstream side in the developer conveyance direction.

A representative configuration of an image forming apparatus has a plurality of developing devices, each of which develops an electrostatic latent image formed on a photosensitive drum into a toner image using developer of plural colors. The image forming apparatus includes a density sensor which detects the amount of toner of the toner image for each color. In a case where it is determined that the amount of toner of any color departs from a predetermined range based on the detection result of the density sensor, development conditions of the rest of the developing devices, other than the developing device departing from the predetermined range, are changed such that the image densities developed by the respective developing devices are equal to each other.

Electrophotographic image forming apparatus with image density control

A developing device includes a developing container unit configured to contain and circulate a developer, and a plurality of developer carrying members each for carrying on its surface the developer for developing an electrostatic latent image on an image bearing member. The developer carrying member providing a largest difference in driving torque measured before and after being coated with a toner on its surface thereof is provided with a plurality of circumferentially spaced grooves, and the remaining developer carrying member has a blast-treated surface.

A developing device includes a developer carrying member for carrying a developer; a first feeding portion for supplying the developer to the developer carrying member while feeding the developer along the developer carrying member; a second feeding portion, communicating with the first feeding portion at end portions thereof, for feeding the developer in a direction opposite to a developer feeding direction of the first feeding portion while collecting the developer from the developer carrying member; and a partition wall portion for partitioning the first and second feeding portions. The partition wall portion includes an opposing portion opposing the developer carrying member with a spacing. A surface roughness of at least the opposing portion is larger than that of the developer carrying member.

The specification discloses a developing device comprises a first developer bearing member configured to bear a developer including a toner and a carrier, and to convey the developer to a first developing region facing an image bearing member, so as to develop an electrostatic latent image formed onto the image bearing member and a second developer bearing member configured to bear a developer transferred from the first developer bearing member, and to develop an electrostatic latent image formed on the image bearing member, by conveying a developer to a second developing region facing the image bearing member and a cover unit configured to shield a route toward the image bearing member from a mutual gap position between the first developer bearing member and the second developer bearing member.

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Toride, Japan

Akihiro Noguchi