Canon Kabushiki Kaisha

Noriyuki Okada

Fumiyoshi Saito

Shozo Aiba

Naoki Mugita

Kenta Matsuzaki

Akinori Miyamoto

Yuya Nagatomo

Masato Maejima

In an image forming apparatus, a cleaning blade, disposed on a downstream side of a transfer roller in a rotation direction of an image carrier, removes toner remaining on the image carrier after transfer of a toner image to an intermediate transfer member. After completion of an image forming operation, a controller causes the transfer roller to separate from the intermediate transfer member, cause the developing device to form on the image carrier a toner band to be supplied to the cleaning blade, and cause rotation of the image carrier to stop such that at least a part of the toner band formed on the image carrier stops within a section from a first position facing the transfer roller to a second position facing the cleaning blade in the rotation direction.

Image forming apparatus

An image forming apparatus includes a calculation portion that calculates an image ratio of the electrostatic image to be formed. A controller controls developer supply from a developer supplier to a developing unit based on the toner density output of an inductance sensor. An adjustment portion adjusts the density of the toner output from the toner density detection portion to a higher value in a case where the image ratio calculated by the calculation portion is higher than a predetermined image ratio.

An image forming apparatus includes a developing device, an image bearing member, an image density detecting portion, a toner content detecting portion, a humidity sensor, a supplying portion, and a controller configured to control the supplying portion so that a toner content is between an upper limit and a lower limit thereof. The controller can execute setting control in which the target value of the toner content is set on the basis of an image density of a reference toner image. The controller sets the lower limit until execution of subsequent setting control, wherein the lower limit is higher when a humidity is a first humidity and an average image ratio is a first ratio than when the humidity is a second humidity higher than the first humidity and the average image ratio is a second ratio larger than the first ratio.

Toner supplying means and image forming apparatus comprising the same

An image forming apparatus includes a control unit configured to be able to perform density adjustment control of forming a reference toner image for image density control on an image bearing member and changing a target value of a toner density based on an image density of the reference toner image detected by an image density detection unit. The control unit limits the target value of the toner density within a predetermined range, and changes frequency of execution of the density adjustment control based on the fact that the target value of the toner density is placed at a boundary value.

An image forming apparatus includes an image bearing member; a developing device; a supply device that supplies the developing device with toner; a density detector that detects information about a toner density serving as a ratio of toner and carrier of the developer of the developing device; and a controller that is able to execute a remaining amount determination mode which interrupts the image forming operation and performs a toner supply operation on the developing device from the supply device, based on the detection result of the density detector. The controller at least selectively executes a first state that immediately prohibits the image formation, a second state that allows the image forming operation, and a third state that executes the mode again, based on the detection result of the density detector acquired after the start of execution of the mode.

Image forming apparatus having control based on toner density

An image forming apparatus includes an image bearing member, a developing device configured to develop an electrostatic image formed on the image bearing member into a toner image, and an exchangeable developer container configured to supply the developer into the developing device. A content sensor detects information relating to a toner content in the developing device, and an exchange detecting portion detects an exchanging operation of the developer container. A controller controls a supplying operation for supplying the developer from the developer container to the developing device on the basis of a detection result of the content sensor and executes a developer supplying mode for supplying developer prohibiting an image forming operation. The controller controls the supplying operation so as to permit the image forming operation without executing the developer supplying mode until an amount of formed images reaches a predetermined level.

Image forming apparatus having developer supplying control

An image forming apparatus includes an image bearing member configured to carry an image, a developing device configured to develop a latent image with a developer including toner and carrier, and a toner content sensor configured to detect a ratio of the toner to the developer in the developing device. A toner container contains the toner to be supplied to the developing device, and a notifying portion notifies necessity for exchange of the toner container when the ratio indicated by the output of the sensor reaches a set level lower than the predetermined range. A controller controls an image forming condition so as to change, on the basis of the output of the toner content sensor, a development contrast wherein the controller sets the development contrast at a level higher than that when the ratio is in the predetermined range, at least in part of a period from when the ratio indicated by the output of the toner content sensor becomes lower than the predetermined range to when the ratio indicated by the output of the toner content sensor reaches a first set level.

Image forming apparatus having development contrast control

An image forming apparatus includes an image bearing member, a developing device, a driving device, and a controller. The developing device includes a developing container, a first feeding member, a second feeding member, a developer carrying member, a content sensor, and a sealing member. Wherein when the controller executes an initializing operation for removing the sealing member from the first opening and the second opening while driving the first feeding member and the second feeding member, the controller provides notification of abnormality when the controller discriminates that an amount of the developer in the second chamber is larger than a predetermined amount at a predetermined timing on the basis of an output of the content sensor.

Image forming apparatus having toner content sensor

An image forming apparatus, which prohibits an image forming operation based on a detection result of a remaining amount detecting unit, thereafter immediately allows the image forming operation based on a detection result of a replacement detecting unit, performs a supply restriction mode which restricts a toner supply amount such that a toner supply amount in a predetermined initial period after allowing the image forming is smaller than that in a normal mode in a case where a detection result of a toner density detecting unit and a target value are under the same conditions, respectively.

Image forming apparatus operable in mode that restricts toner supply

An image forming apparatus includes: an image bearing member; a developing device; a supply device which supplies toner to the developing device; a density detector which detects information about a toner density as a ratio of toner and carrier of the developer of the developing device; and a controller which interrupts an image forming operation and is capable of executing a forced supply mode of performing the toner supply to the developing device from the supply device, based on first information of at least one of detection results of the density detector and information about a toner consumption, second information about the amount of supply operation supplied by the supply device, in which the controller determines whether or not to execute the forced supply mode, and third information about an accumulated value of the amount of toner consumption after the forced supply mode executed last time.

Image forming apparatus with forced toner supply mode

An image forming apparatus includes an image forming portion; a supplying device for supplying a toner; a transfer device capable of transferring the toner image from the image forming portion onto a toner image receiving member; a first detecting portion for detecting a transfer current of the transfer device; a second detecting portion for detecting information on a toner amount of the transferred toner image; and a controller for controlling, during non-image formation, a supplying operation of the supplying device on the basis of a detection result of the first detecting portion when a toner image for measurement formed at the image forming portion is transferred by the transfer device at a transfer voltage lower than a discharge start voltage and on the basis of a detection result when the toner image for measurement transferred on the toner image receiving member is detected by the second detection portion.

An image forming apparatus includes photosensitive drums, electrostatic latent image forming units, developing sleeves, patch detection sensors which detect image densities of the toner images formed by the electrostatic latent image forming units, and toner replenishment units which replenish the developing sleeves with the toner based on the detection results of the patch detection sensors. Further, controllers are provided to control the rotation speeds of the developing sleeves at the time of forming the reference toner image to be higher than the rotation speeds of the developing sleeves at the time of forming a normal image.

The present image forming apparatus forms a reference developing material image on an image carrier using an exposure unit and a developing unit before executing auto tone correction processing, and detects the density of the reference developing material image formed on the image carrier. If the detection result indicates that the toner charge amount of the developing material contained in the developing unit is within a predetermined range, auto tone correction processing is executed, whereas if the detection result of the density detecting unit indicates that the toner charge amount of the developing material contained in the developing unit is outside the predetermined range, adjustment processing for adjusting the toner charge amount of the developing material contained in the developing unit to be within the predetermined range is executed before execution of auto tone correction processing.

An image forming apparatus includes an image bearing member for carrying a toner image; a rotatable transfer member constituting a transfer portion for transferring the toner image from the image bearing member onto a recording material; a voltage source for applying a voltage to the transfer member; an executing portion for executing an image forming mode for continuously forming an image on a plurality of recording materials having different widths measured in a direction of a rotational axis of the transfer member; an interval adjustment portion for adjusting, during execution of the image forming mode, an interval between adjacent recording materials to a first interval when the width of the recording material is larger than the width of the previous recording material, and for adjusting, during execution of the image forming mode, the interval between adjacent recording materials to a second interval when the width of the recording material is smaller than the width of the previous recording material.

An image forming apparatus includes a image bearing member (drum); a developing device for forming a developing portion at which an electrostatic latent image formed on the drum is developed with toner; a toner supply device for supplying toner to the developing device; a density detecting portion for detecting a density of a control toner image formed on the drum; a toner ratio detecting portion for detecting a toner ratio in a two component developer contained in the developing device; a transfer member for forming a transfer portion; a charging member for electrically charging the toner image formed by the developing device by being supplied with a bias of an identical polarity to a charge polarity of the toner; an adjusting portion for adjusting an amount of the toner supplied from the toner supply device so that the toner ratio is below a preset lower limit when the toner ratio detected by the toner ratio detecting portion reaches the lower limit; and a bias determining portion for determining, after the adjustment by the adjusting device, a condition of a bias to be applied to the charging member on the basis of a detection result of the density detecting portion with respect to the density of the control toner image formed on the drum.

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Matsudo, Japan

Noriyuki Okada