Abstract: A dust container includes a container body, an inlet, a dust detector, and a dust-conveying unit. The dust-conveying unit conveys the dust from the inlet to the interior of the container body. The dust-conveying unit includes a plurality of conveying members that are arranged at different positions in the dust conveying unit. A direction in which the dust is conveyed and an amount of the dust conveyed by at least one of the conveying members is different from those of the other conveying members. As the dust accumulates in the container body, the dust detector detects whether the container body is substantially full with the dust.

Abstract: A developing device includes: a replaceable toner cartridge; a development chamber; a first transport path which connects the toner cartridge to the development chamber; a first transport unit which transports toner from the toner cartridge to the development chamber through the first transport path; a second transport path which connects the development chamber to the toner cartridge; and a second transport unit which discharges the toner within the development chamber to the toner cartridge through the second transport path at the time of replacement of the toner cartridge.

Abstract: A developer cartridge for supplying a toner-containing developer, including a developer containing portion; a developer recovery portion, disposed at one end of the developer containing portion in a longitudinal direction; a supply port that supplies the developer from the developer containing portion to the developing unit; a recovery port through which used developer supplied from the developing unit passes to the developer recovery portion; and an opening and closing member, coupled to the outer circumferential of the developer containing portion and the developer recovery portion, that opens or closes the supply port and the recovery port. The developer containing portion has first and second end portions, the first end portion being more slender than the second end portion and linked to the developer recovery portion, wherein a tapered portion is provided between the first end portion and the second end portion.

Abstract: A toner cartridge having a magnetically coupled drive apparatus is provided. The cartridge provides a first toner holding member that houses toner and a second toner holding member adjacent to the first member that houses toner. A dividing wall separates the first toner holding member from the second toner holding member. A toner shifting component shifts the waste toner housed in the first toner holding member and a toner stirring component stirs the fresh toner housed in the second toner holding member. The toner shifting component and toner stirring component are magnetically coupled through the dividing wall so that when the toner stirring component rotates the toner shifting component rotates. The magnetic coupling disposed between the toner shifting component and toner stirring component engages without an opening through the dividing wall. As a result, waste toner cannot pass through the dividing wall into the fresh toner housing and vice versa.

Abstract: A toner bottle for use in a marking device with a feed mechanism. The toner bottle includes first and second compartments for holding fresh and waste toner, respectively. The feed mechanism allows fresh toner to be delivered to the marking engine from the bottle and waste toner to be returned to the bottle from the marking engine.

Abstract: A toner container installed in an image forming apparatus includes a toner container main body having a predetermined length and in which toner is accommodated, a discharge port through which the toner is discharged from the toner container main body, a shutter which opens and closes the discharge port, a handle provided on the toner container main body, and a pressed portion provided on the toner container main body and which is pressed by the image forming apparatus to project the handle out from the image forming apparatus.

Abstract: A developing unit includes a developer cartridge containing developer and a developing cartridge with a developing cartridge body comprising a mounting portion and a cover member. The mounting portion accepts the developer cartridge for replenishing developer consumed by the developing cartridge. The cover member closes an opening of the mounting portion when the developer cartridge is not inserted into the mounting portion. When a developing unit is initially constructed, printing is performed using developer contained in the developing unit. A developer cartridge containing developer can be inserted into the developing unit, allowing the supply of developer in the developing unit to be replenished.

Abstract: A toner container for installation in a toner supply device is provided. The toner container includes a toner accommodation member and a cap member freely attachable to and detachable from the toner accommodation member. The toner accommodation member includes a bag member having an opening, and a connection member attached to the opening of the bag member and having a toner supply opening. The cap member is configured to receive toner supplied from the toner supply opening of the connection member of the toner accommodation member and to discharge the received toner. Either of the connection member of the toner accommodation member and the cap member includes a groove part and the other includes a protrusion part to engage with the groove part, and the cap member is attached to the toner accommodation member by engaging the groove part and the protrusion part with each other. The protrusion part elastically deforms to engage with the groove part.

Abstract: A toner cartridge includes a container defining a central axis and a toner-guiding member. The container is provided at one end thereof with an opening having a radius. The toner-guiding member is provided with an annular connecting portion connected with the container, an outlet at one end thereof, a longitudinally-extending portion at the other end thereof extending into the container through the opening, an inlet formed on the longitudinally-extending portion, and a flexible scraping piece mounted on the longitudinally-extending portion and adjacent to the inlet. The scraping piece has a distal end defining with the central axis a distance longer than the radius of the opening, such that the toner in the container can be substantially fully discharged out of the toner cartridge so as to lower the residual quantity of toner in the toner cartridge.

Abstract: With a structure in which gear trains 5, 6 of a developer supply container 1 are locked by a locking member 7, and the gear trains 5, 6 receive a drive from a gear 12 of a developer receiving apparatus 10, thus accomplishing automatic setting rotation of developer supply container 1, when the developer supply container 1 is once dismounted and then remounted, the locking member 7 is in a non-locking position, and therefore, the setting rotation of the developer supply container 1 cannot be effected automatically. With inserting operation of the developer supply container 1, an inducing portion 7c of the locking member 7 is pushed and raised by a guide portion 10j provided in a groove portion of the developer receiving apparatus 10, so that locking member 7 effects its locking operation.

Abstract: A developing device including a developing unit configured to develop an electrostatic latent image with a toner; a toner cartridge configured to contain the toner and supply the toner to the developing unit, and including an agitator configured to agitate the toner, wherein the toner cartridge is detachably attached to the developing unit; at least one opening configured to pass the toner between the developing unit and the toner cartridge; and at least one control valve configured to open and shut the opening, wherein a toner replacement ratio (b/a) of the developing device satisfies relationship 0.05?b/a?2.0, wherein a represents an amount of the toner supplied to the developing unit from the toner cartridge per a unit time and b represents an amount of the toner discharged to the toner cartridge from the developing unit per the unit time.

Abstract: An image forming apparatus includes a developer reservoir, a detector, a computing section, a display unit, and a controller. The developer reservoir holds developer therein. The detector detects when the developer decreases to a first amount (i.e. toner-low level) The computing section computes current accumulated developer usage. The current accumulated developer usage is displayed on the display unit. The controller controls the display unit to display the current accumulated developer usage. When the detector detects the first amount, the controller controls the display unit to display a first value of the current accumulated developer usage that has been consumed until the first amount is detected.

Abstract: An image forming apparatus includes: an image carrier on which an electrostatic latent image is formed; a toner cartridge detachably mountable to the image forming apparatus, including a toner casing accommodating a developing agent, an opening/closing member which opens/closes an opening formed in the toner casing to discharge the developing agent, and an operation member operating the opening/closing member; and a developing unit to develop the electrostatic latent image by the developing agent discharged from the opening. The operation member can move between an open position for operating the opening/closing member to open the opening, and a close position for operating the opening/closing member to close the opening, and the operation member forms a part of a transport path of a recording medium in the image forming apparatus at the open position in a state where the toner cartridge is mounted in the image forming apparatus.

Abstract: A developer supply container (1) detachably mountable to a hollow portion of a rotatable photosensitive member (100) provided in a electrophotographic image forming apparatus, the container including a rotatable container body having an inner space for containing a developer; a feeding portion (5) for feeding the developer in the container body with a rotation of the container body to discharge the developer out of the container body; and a engageable portion (3a) which is engageable with the photosensitive member so that container body is rotated integrally with the photosensitive member by a rotational driving force received from a driving member (104) provided in the electrophotographic image forming apparatus.

Abstract: An image forming device includes a removable cartridge holding toner, supplying toner to a developer. The cartridge and developer each include a shutter to retain toner when the cartridge is removed. Upon insertion, the developer abuts the cartridge shutter, and the cartridge abuts the developer shutter, such that movement of the shutter into the image forming device opens both the shutters. Additionally upon insertion, the cartridge shutter releasably engages with the developer, and the cartridge releasably engages with the developer shutter. Upon removing the cartridge, the developer pulls the cartridge shutter closed prior to releasing engagement, and the cartridge pulls the developer shutter closed prior to releasing engagement. The opening and closing of both shutters requires only a single movement by the user: inserting or removing the cartridge from the image forming device.

Abstract: A resin-made holding member made of an integrally built spring and holder wherein the spring is made up of a plurality of ring-shaped elastic pieces connected with one another, and the average wall thickness of each elastic piece at the end in the longest axial direction of inner diameter of the ring shape is greater than the average wall thickness of other portions.

Abstract: An image forming process module is provided having an integrated photoreceptor unit and development unit, and an image forming apparatus having the same. The image forming process module includes a photoreceptor unit having at least one photoreceptor on which an electrostatic latent image is formed. A development unit is installed around the outer surface of the photoreceptor and having a plurality of development assemblies for developing the latent image, thereby forming a visual image. A fixing frame is detachably installed to a main body of an image forming apparatus for fixing the photoreceptor unit and the development unit to be integrated into a single module. The image forming process module has the enhanced assembly and replacement efficiencies because the photoreceptor unit and the development unit are simultaneously installed to and uninstalled from a main body of an image forming apparatus as a single module.

Abstract: A developer collection container includes a developer storing portion having first and second end portions in a longitudinal direction thereof. A developer supply opening is provided on the first end portion through which the developer is supplied into the developer storing portion. A rotation member is rotatably provided so as to extend substantially from the first end portion to the second end portion. The rotation member rotates so as to convey the developer in the longitudinal direction of the developer storing portion. In a first region closer to the first end portion, the rotation member conveys the developer in a direction from the first end portion toward the second end portion with a conveying power which is larger than a conveying power with which the rotation member conveys the developer in a second region closer to the second end portion.

Abstract: A waste toner collecting apparatus of the present invention reliably prevents waste toner from spilling when replacing the waste toner box by opening the front cover of an image forming apparatus as the first through fifth shutters close the respective waste toner conveyance end sections. The first through fifth shutters are locked when no waste toner box is mounted in the image forming apparatus. The first through fifth shutters are unlocked when a waste toner box is mounted in the image forming apparatus. It can reliably prevent an operation error of operating the image forming section with the waste toner conveyance end sections left in an open state as the stay of the cover presses the first through fifth shutters when a waste toner box is not mounted.

Abstract: A developer collecting container detachably mountable to a rotatable member which is provided in an image forming apparatus to rotate a developing device, the developer collecting container which is rotatable while being substantially fixed to the rotatable member with the developing device, the developer collecting container includes a receiving port for receiving a developer discharged from the developing device; an accommodating portion for accommodating the developer collected from the developing device; a guiding pipe, having a discharge opening for permitting discharging of the developer into the accommodating portion, for guiding the developer receiver at the receiving port with rotation of the rotatable member to the discharge opening, wherein the discharge opening is disposed adjacent a center of gravity of the developer collecting container.

Abstract: An image forming apparatus, which uses a developing device including: a developer carrying member; a developer containing portion; an agitating member agitating a developer; a developer amount detecting member outputting a signal for detecting the remaining amount of the developer contained in the developer containing portion, the image forming apparatus including a main body controller detecting the remaining amount using a first detecting unit that sets a reference value as a reference for detecting the remaining amount by the signal, and thereafter calculates the remaining amount based on an amount of change in the signal from the reference value, and a second detecting unit that detects the remaining amount based on a band of fluctuation in the signal corresponding to a rotational period of the agitating member.

Abstract: A developer container (130) for an image forming apparatus includes a developer container main body (131) having an axial intermediate portion radially opened and a supporting member (132) for supporting an intermediate portion in an axial line direction of the developer container main body (131) over the entire periphery thereof from radially outside as the developer container main body (131) is rotatable around the axial line (L131). A through hole (151) for guiding the developer from the developer container main body (131) to outside.

Abstract: A waste toner storage unit detachably mountable to an image forming apparatus includes a waste toner container and an inner cover integrally attached to the waste toner container. The waste toner container stores waste toner recovered after an image forming process. The inner cover is located at a region of the waste toner storage unit that does not store waste toner.

Abstract: An electrophotographic image forming apparatus is provided with a developer collecting device which collects developer removed from an image bearing member and an intermediate transfer body by a cleaning section. The developer collecting device comprises a positioning frame for determining a mounting position of the image bearing member onto an image forming apparatus main body; a waste developer container detachably mounted on the positioning frame 4, for accommodating waste developer collected by the cleaning section; and an integrated container detection section for detecting whether or not the waste developer container is mounted on the positioning frame and whether or not the waste developer container is filled up with the waste developer.

Abstract: Provided is an imaging cartridge with a universal body sculpted to mate with the imaging cartridge-receiving cavity of a plurality of imaging machine models. The universal body of the imaging cartridge enables the cartridge to be used with imaging machines made by different manufacturers, and different imaging machine models made by a common manufacturer. A plurality of recesses is formed in the leading end of the imaging cartridge body that accepts protuberances in an imaging machine's cartridge-receiving cavity and enables the cartridge to mate with a plurality of printers.

Abstract: The present invention provides the image forming apparatus for successively performing information communication between an attaching part and the main body of the image forming apparatus. The communication-end antenna section 11 is provided in the toner supplying holder-containing section 3 in the main body of the image forming apparatus, so as to face the IC tag in the toner supplying holder 2. The toner supplying holder-containing section 3 is covered with the electromagnetic shield material 7.

Abstract: An image forming apparatus is provided with a body; a developing unit formed inside the body; a toner accommodation unit mounted inside the body and provided with at least two or more cartridges; and a toner supply unit for supplying toner discharged from each cartridge of the toner accommodation unit to the developing unit, such that a user can easily change the toner.

Abstract: A waste developer collecting device ejects and collects a waste developer used in a developing unit employing a two-component developing system in which a developer that contains toner and carrier is used. The waste developer collecting device includes: an opening and closing section for opening and closing a developer ejection opening formed on a bottom portion of the developing unit; an opening operation prohibiting section for prohibiting the opening operation of the opening and closing section; a collecting container for collecting the developer ejected through the developer ejection opening; and a collecting container fixing section for fixing the collecting container at a position where the developer ejected from the developing unit is collected. The opening operation prohibiting section allows the opening operation of the opening and closing section when the collecting container is coupled to the collecting container fixing section.

Abstract: A toner container installed in an image forming apparatus, the toner container including a toner container main body having a predetermined length and which accommodates toner, a mixer which stirs the toner in the toner container main body, a discharge port through which the toner in the toner container main body is discharged from the toner container main body, a screw having one end projected from one end surface of the toner container main body, the screw being rotated to convey the toner from the toner container main body to the discharge port, a coupling portion provided at the one end of the screw and rotated by a driving portion provided in the image forming apparatus, and a protruding portion provided on an outer peripheral surface of the coupling portion.

Abstract: An imaging cartridge is detachably loaded into an image forming apparatus body. A process unit has a developing device for developing an electrostatic latent image on a photoconductor to form a toner image, and a cleaning device for collecting toner remaining on the image bearing body even after transfer of the toner image. A new toner box is detachably attached to the process unit and serves for storing therein unused toner fed to a developing device. A waste toner box is detachably attached to the process unit and serves for storing therein waste toner collected by the cleaning device. A support mechanism couples the new toner box and the waste toner box to each other so as to be supported each other in a manner allowing elastic relative displacement.

Abstract: The image forming apparatus (10) includes the apparatus main body (11), the plurality of photosensitive drums (121) arranged within the apparatus main body (11) in such a manner as to be aligned in a row in a horizontal direction, the plurality of developing devices (122) arranged within the apparatus main body (10) to be associated with the photosensitive drums (121) and supplying toners to the corresponding photosensitive drums (121), and the plurality of toner containers (20) detachably mounted within the apparatus main body (11) in such a manner as to be aligned in a row along the alignment direction of the photosensitive drums (121) while being associated with the developing devices (122). In this image forming apparatus (10), the alignment pitch of the toner containers (20) is set to be greater than the alignment pitch of the photosensitive drums (121).

Abstract: A toner cartridge is attachable/detachable to/from a main body of an image forming apparatus. A code pattern is provided on an outer peripheral surface of the toner container and can be read by a photosensor or a mechanical switch. The code pattern includes a first pattern string which is provided on the outer peripheral surface of the toner container along an insertion direction and in which a first and a second patterns respectively indicating different binary levels are alternately arranged at a specified period, and a second pattern string which is provided to be shifted from the first pattern string in the insertion direction by almost a half period and in which the plural first patterns and the plural second patterns are combined and are arranged.

Abstract: A coupling member of a toner supply container in a toner supply system detachably mountable to an image forming apparatus, includes a rotatable engagement portion provided with a hook portion which is hook-engageable with an engagement member provided in the image forming apparatus to receive a rotational force for discharging the developer in the container; a release portion for receiving a force, for displacing the hook portion inwardly in a radial direction, from a hollow release member provided in the image forming apparatus so as to release engagement of the hook portion with the engagement member; and a regulation portion provided with a hollow cylindrical portion in which a regulation shaft provided in the image forming apparatus is insertable to regulate an inclination of the coupling member by contact with the regulation shaft when the coupling member is moved away relative to the engagement member in an axial direction of the engagement portion in a state in which the release portion receives the fo

Abstract: In a developer-storing container of the present invention, an agitation blade used in a toner-storing section and an agitation blade used in a waste-toner-storing section are coupled by a rotor. The rotor is interdigitated to a bearing mounted on a partition wall. The partition wall is made to be a fixed wall so that precision of interdigitation of the agitation blade of the toner-storing section, the rotor, and the agitation blade of the waste-toner-storing section is improved. Consequently, a developer-storing container that is easy to assemble and in which precision of interdigitation is high is realized.

Abstract: A liquid-type image forming apparatus includes a developer cartridge, and a method for disposing of the developer cartridge. The developer cartridge includes a cartridge body having a first chamber for storing a developer and a second chamber for storing an absorber that absorbs waste developer of the first chamber. A sealing member is arranged between the first chamber and the second chamber and is configured to separate by an external force for fluidly connecting the first and second chambers.

Abstract: A container holding device includes a container guide member (60) that holds a toner container (50). The toner container (50) can be detachably attached to the container guide member (60). The toner container (50) includes a soft, shrinkable bag (51) for storing contents such as toner. The container guide member (60) can move between a first position at which the toner container (50) is detachably attached and a second position at which the contents of the toner container (50) can be discharged. A moving unit moves the container guide member (60) between the first and second positions. An external pressurizing unit shrinks the bag (51) by applying external pressure, and applies a lower pressure when the container guide member (60) is at the first position than at the second position.

Abstract: An actuating structure formed in a toner cartridge adapted to actuate a physical sensor inside the printer which activates the printer when the door is closed. The actuating structure is displaced when the cartridge is inserted in printers that do not use a physical sensor in that location. Accordingly, the toner cartridge is functional in a plurality of printers. The toner cartridge can also have a plurality of actuating structures.

Abstract: A toner-collecting device includes a toner-collecting unit, a shaft member, and a guide member. The toner-collecting unit is configured to be detachably attachable. The shaft member is rotatably arranged in the toner-collecting unit. The guide member includes a sliding portion that allows the shaft member to slide while the shaft member is being inserted from one end to an opposite end of the toner-collecting unit.

Abstract: A toner container which is mountable and removable at a main body of an image forming apparatus, the toner container comprising: at least one toner filling port provided in a casing body of the toner container; and a sealing member which covers the toner filling port and a predetermined range of surroundings of the toner filling port, from an outer side of the casing body, for sealing toner inside the casing body, is provided.

Abstract: A toner cartridge is detachably attached to an image forming apparatus and supplies toner to the image forming apparatus. The locking mechanism is positioned either at a locking position or at a non-locking position. Shortly after the toner cartridge has been attached to the image forming apparatus, the locking mechanism is at a non-locking position. When a user operates a driving member of the toner cartridge after the toner cartridge has been attached to the image forming apparatus, the operating lever engages the locking mechanism to cause the locking mechanism to move to a locking position. When the locking mechanism is at the locking position, the locking mechanism limits the driving member to move relative to the engagement portion, so that the toner cartridge is not allowed to be detached from the image forming apparatus.

Abstract: A toner supply device is equipped with a coupling that has a toner supply opening on the side wall, a partition wall provided in this coupling integrally with a specific space provided on the inner wall and a hole larger than a toner supply opening on the side wall. A toner bottle containing toner is provided in the coupling with its cap portion inserted airtight into the partition wall detachably and an opening provided on its cap portion opposing to the hole on the partition wall for replenishing toner to a developing device from this opening through the hole and a toner supply opening.

Abstract: A developing apparatus includes a developer carrying member for carrying thereon and conveying a developer to a portion opposed to an image bearing member; a first chamber having the developer carrying member disposed in an opening thereof; a conveying member disposed in the first chamber for conveying the developer; a second chamber to which the developer is supplied from the first chamber through a first communicating portion and which supplies the developer to the first chamber through a second communicating portion to the first chamber; an agitating and conveying member disposed in the second chamber and rotatable to thereby agitate and convey the developer, wherein the second chamber and the agitating and conveying member are disposed while being inclined with respect to a horizontal direction; and developer supplying means for supplying a developer to be supplied, from just above an area of the second chamber.

Abstract: A developer cartridge holds developer that is supplied into a print process cartridge of an image forming apparatus. The developer cartridge includes a fresh developer chamber and a waste developer chamber. The fresh developer chamber holds fresh developer in it. The waste developer chamber holds waste developer in it. An inlet is formed in the waste developer chamber. The waste developer is received through the inlet into the waste developer chamber. A first opening-and-closing member opens and closes the inlet. A mechanism drives the first opening-and-closing member to open the inlet when an operating member is positioned to a first position after the developer cartridge is attached to the print process cartridge. The mechanism driving the first opening-and-closing member to close the inlet when the operating member is positioned to a second position before the developer cartridge is detached from the print process cartridge.

Abstract: The development device of the present invention has a rotating shutter supported rotatably between a supply opening formed on a toner supply device and a receiving opening formed on a developing tank. The rotating shutter has an open section extending in the axial direction of the roller-shaped main section as well as opened in the direction perpendicular to the axial direction thereof, opening and shutting the supply opening in conjunction with attachment and detachment operation of the developing tank. The rotating shutter shuts the supply opening by covering the supply opening with the outer surface of the roller-shaped main section, and opens the supply opening by communicating the supply opening and the receiving opening through the open section. Thus, it is possible to prevent the leakage of toner even after repetitively performing the attachment and detachment operation of the developing tank.

Abstract: A toner recovery device, capable of preventing toner from spilling out of the space between protruding sections and an inner wall of a toner-conveying pipe, and process cartridge and image forming apparatus having this device. Residual toner after transfer, which is carried into a carry-in section of the toner-conveying pipe, is held by the protruding sections of a toner-conveying belt and a bottom surface of the toner-conveying pipe, and conveyed to a carry-out section. Accordingly, the residual toner after transfer can be prevented from oscillating while being conveyed to the carry-out section. Therefore, the residual toner after transfer is prevented from spilling out of the space between the protruding sections and the inner wall of the toner-conveying pipe, and the amount of residual toner after transfer to be conveyed to the carry-out section can be prevented from being reduced.

Abstract: A wet-type electrophotographic image forming apparatus comprises a main body, a developing unit disposed inside the main body, a developer cartridge for providing developer to and collecting developer from the developing unit, and a fitting unit for connecting the developer cartridge with the developing unit. The fitting unit comprises a first fitting part disposed in the main body, a second fitting part disposed in the developer cartridge, and a third fitting part disposed in the developing unit. The fitting unit is connected to and disconnected from the second and third fitting parts by raising and lowering the parts. The method of setting up the system includes the step of raising a first female fitting part to connect first and second female fitting parts with a male fitting part.

Abstract: If a user is not familiar with the operation for a developer supply container, the rotating operation for the developer supply container may be insufficient, so that developer supply container does not reach a predetermined operating position, with the result of abnormal developer supply. By increasing a rotation load of a second gear which is in an operable connection with a drive gear member of the developer receiving apparatus by a function of a locking member, the developer supply container mounted to the developer receiving apparatus is rotated toward the supply position. After the developer supply container rotates to the supply position, the locking by the locking member is released, by which the rotation load applied to the second gear is reduced, so that drive transmission, thereafter, to the feeding member for developer supply is smooth.

Abstract: An image forming apparatus includes an image bearing member on which an electrostatic image is to be formed; a developing device for developing the electrostatic image with a developer; a developer container detachably mountable to a mounting portion provided in a main assembly of the apparatus, for accommodating a supply of developer; a discharging device for discharging the supply of developer from the developer container mounted to the mounting portion to an outside of the developer container; a first developer accommodating portion for receiving the developer from the discharging device and for accommodating an amount of the developer which exceeds a first predetermined amount, wherein the first amount is larger than a capacity of the developer container; a first detecting device for detecting an amount of the developer in the first accommodating portion; a first supplying device for supplying the developer in the first accommodating portion to an outside of the first accommodating portion; a second devel

Abstract: A developing device configured such that the developing device or the like can be easily inserted and removed without increasing the size of the apparatus, and an image forming apparatus that uses this developing device as well as a process cartridge. The developing device is provided with a first rib formed projecting from a first main wall surface, which is the side surface with the maximum area in the chassis of the developing device, and a second rib formed projecting from a second main wall surface, which is the side surface in opposition to the first main wall surface, the first rib being disposed in a position higher than the second rib in the height direction.

Abstract: To provide a technology capable of realizing high-accuracy detection of toner density. A developing apparatus includes: a partition plate provided within the developing apparatus for partitioning an interior of the developing apparatus into a plurality of space; plural transport mixers each provided in the space within the developing apparatus partitioned by the partition plate and rotating for stirring and transporting a developer including toner and carrier; a density sensor provided in a transport path of the developer in one space of the plurality of space partitioned by the partition plate for detecting toner density of the stirred and transported developer; and retracting part for retracting an amount of the developer more than a predetermined amount into another space than the space in which the toner density is detected by the density sensor so that the amount of developer is constantly equal to or less than the predetermined amount near a toner density detection position by the density sensor.