JP2024039449A - Image forming device - Google Patents

Abstract

An object of the present invention is to efficiently suppress falling and contamination of scattered toner from a scattered toner suction duct when replacing a developing device. [Solution] An image forming apparatus includes an image carrier, a developer container that stores developer, a conveying member that agitates and transports the developer stored in the developer container, and a developer carrier that rotates while supporting the developer. a scattered toner collecting section disposed on the downstream side in the rotational direction of the developer carrying member along a gap between the image carrying member and the developer carrying member, and a collecting unit connected to the scattered toner collecting section. a developing device which is connected to the collection duct and which develops the electrostatic latent image formed on the image carrier with the developer carried on the developer carrier; the image forming apparatus includes an air blowing mechanism that sucks the toner that has been collected, and when the developing device is replaced, the air blowing mechanism is operated to suck the toner collected in the collection duct and the scattered toner collection section. [Selection diagram] Figure 11

Description

The present invention relates to an image forming apparatus that forms images using a developer using an electrophotographic method or the like.

2. Description of the Related Art Conventionally, as image forming apparatuses that form images using a developer using an electrophotographic method or the like, those employing a two-component developing method have been popular, especially in models that perform high-speed output and high-quality output. In this type of two-component developing device, the toner and carrier, which is magnetic particles, are stirred and conveyed within the developing device to be triboelectrically charged, and only the toner is attached to the electrostatic latent image in the developing section. On the other hand, image forming apparatuses are required to output images at higher speeds and with higher image quality, as well as to simplify maintenance. One of the ways to simplify maintenance is to reduce toner contamination inside the image forming apparatus. If the inside of the image forming apparatus becomes contaminated with toner, not only will the output image become defective such as stains, but cleaning will be required when replacing the developing unit or photosensitive drum unit. Furthermore, if it adheres to each drive system, drive slippage may occur, which may affect accurate drive.

One of the causes of toner contamination inside an image forming apparatus is toner scattering, in which toner scatters from within the developing apparatus in two-component development. Inside the developing device, toner and carrier adhere to each other due to electrostatic force due to frictional charging. However, toner scattering occurs when the scattered toner generated when this electrostatic adhesion is released due to impact is discharged from the inside of the developing device along with the airflow.

In order to solve this problem caused by toner scattering, a suction port is provided at the end of the developer container downstream from the position where the developer carrier faces the image carrier, and the scattered toner is sucked through the suction port. An image forming apparatus has been developed (see Patent Document 1). In this image forming apparatus, a suction duct is connected to the suction port, and a suction fan is connected to the suction duct, so that scattered toner scattered from inside the developing device is sucked together with the surrounding air.

Furthermore, when using a suction duct, a toner receptacle is installed below the connection to prevent toner that has accumulated at the connection between the development device side of the suction duct and the image forming apparatus main body side from falling due to detachment when replacing the development device. A developing device has also been developed (see Patent Document 2).

Japanese Patent Application Publication No. 2005-257739 JP2017-26737A

However, in the image forming apparatus described in Patent Document 2, since the toner that has fallen outside the developing device is retained, there is a risk that the toner falling from there may stain the inside of the main body or the installation location.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can efficiently suppress falling of scattered toner from a scattered toner suction duct and contamination when replacing a developing device.

In order to achieve the above object, an image forming apparatus of the present invention includes an image bearing member, a developer container containing a developer, a transport member that stirs and transports the developer contained in the developer container, and a transport member that carries the developer. a developer carrier that rotates, a scattered toner collecting section disposed on the downstream side in the rotational direction of the developer carrier along a gap between the image carrier and the developer carrier, and the scattered toner a collection duct connected to the collection section, and a developing device configured to develop an electrostatic latent image formed on the image carrier with a developer carried on the developer carrier; an image forming apparatus comprising: a blower mechanism that sucks toner collected in a scattered toner collecting section; the blowing mechanism is operated when the developing device is replaced to suck the toner collected in the collecting duct and the scattered toner collecting section; Characterized by suction.

According to the present invention, it is possible to efficiently suppress falling of scattered toner from the scattered toner suction duct and contamination when replacing the developing device.

FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment. 1 is an XZ cross-sectional view showing a schematic configuration of a developing device according to a first embodiment. 1 is a YZ sectional view showing a schematic configuration of a developing device according to a first embodiment; FIG. FIG. 1 is an XY sectional view showing a schematic configuration of a developing device according to a first embodiment. FIG. 3 is a diagram showing a scattered toner collection configuration of the developing device according to the first embodiment. FIG. 3 is a diagram showing toner falling from the scattered toner collection duct according to the first embodiment. FIG. 7 is a diagram illustrating a process of removing the developing device when replacing the developing device according to the first embodiment. FIG. 7 is a diagram illustrating a process of removing the developing device when replacing the developing device according to the first embodiment. FIG. 3 is a diagram showing measures against toner falling from a scattered toner collection duct according to the first embodiment. FIG. 2 is a block diagram when taking measures against toner falling from a scattered toner collection duct according to the first embodiment. 2 is a flowchart of measures against toner falling from a scattered toner collection duct according to the first embodiment. 5 is a timing chart of countermeasures against toner falling from a scattered toner collection duct according to the first embodiment. FIG. 7 is a diagram illustrating measures against toner falling from a scattered toner collection duct according to a second embodiment. 7 is a flowchart of measures against toner falling from a scattered toner collection duct according to a second embodiment. 7 is a timing chart of countermeasures against toner falling from a scattered toner collection duct according to a second embodiment. FIG. 7 is a diagram illustrating measures against toner falling from a scattered toner collection duct according to a third embodiment. 12 is a flowchart of measures against toner falling from a scattered toner collection duct according to a third embodiment. 12 is a timing chart of countermeasures against toner falling from a scattered toner collection duct according to a third embodiment.

<First embodiment>
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 12. In this embodiment, a tandem-type full-color printer that forms an image on a recording medium using an electrophotographic method is described as an example of the image forming apparatus 1. The image forming apparatus 1 is not limited to a tandem type in which a plurality of image forming sections are arranged side by side, but may be a rotary type in which a plurality of image forming sections are arranged in a cylindrical shape. Further, the toner image is not limited to an intermediate transfer method in which the toner image is primarily transferred to an intermediate transfer member and then secondarily transferred to a sheet S as a recording material, but may also be a direct transfer method in which the toner image is directly transferred from the photoreceptor to the sheet. Furthermore, it is not limited to full color, but may be monochrome or monochrome, and can be implemented in various applications such as printers, various printing machines, copying machines, faxes, multifunction machines, etc. The recording medium is a sheet S, which includes, in addition to plain paper, special papers such as coated paper, recording materials of special shapes such as envelopes and index papers, and plastic films and cloth for overhead projectors.

[Image forming device]
FIG. 1 is a cross-sectional view of the image forming apparatus 1. As shown in FIG. As shown in FIG. 1, the image forming apparatus 1 is an intermediate transfer tandem type full-color copying machine in which image forming units PY, PM, PC, and PK of four colors are arranged side by side on an intermediate transfer belt 15. The image forming apparatus 1 forms an image on a sheet S using an electrophotographic method. The image forming apparatus 1 forms a full-color image by superimposing images of four colors, ie, yellow, magenta, cyan, and black. At the top of the image forming apparatus 1, an operation section (not shown) that is operated by a user is provided. The image forming apparatus 1 is controlled by a control section 50 (not shown in FIG. 1, but shown in FIG. 10).

In this embodiment, a two-component development method is used in which a developer containing toner and a carrier is used. The image forming unit PY forms a yellow image using yellow toner. Image forming section PM forms a magenta image using magenta toner. The image forming unit PC forms a cyan image using cyan toner. Image forming section PK forms a black image using black toner. The configurations of each image forming unit PY, PM, PC, and PK are basically the same except for the color of the toner they contain. The configuration and image forming process will be explained.

The image forming unit PY includes a photosensitive drum 10, which is a drum-shaped electrophotographic photosensitive member that rotates in the direction of the arrow (counterclockwise) and serves as an image carrier that carries a toner image. The photosensitive drum 10 has a diameter of 30 mm, for example. A charger 11, a laser beam scanner 12 as an exposure means, a developing device 30, a transfer roller 13, a cleaning device 14, and the like are arranged around the photosensitive drum 10.

Next, the image forming sequence in the normal mode of the entire image forming apparatus 1 having the above configuration will be described. First, the photosensitive drum 10 is uniformly charged by the charger 11. In the normal mode, the photosensitive drum 10 rotates counterclockwise as indicated by the arrow at a process speed (peripheral speed) of, for example, 217 rpm. The uniformly charged photosensitive drum 10 is then scanned and exposed by a laser beam modulated by an image signal by a laser beam scanner 12.

The laser beam scanner 12 has a built-in semiconductor laser, and this semiconductor laser is controlled based on input image data and emits a laser beam. For example, laser light is controlled in response to a document image information signal (image data) input from a document reading device having a photoelectric conversion element such as a CCD, or in response to an image information signal input from an external terminal. Inject. As a result, the surface potential of the photosensitive drum 10 charged by the charger 11 changes in the image area, and an electrostatic latent image is formed on the photosensitive drum 10.

The electrostatic latent image thus formed on the photosensitive drum 10 is reversely developed with toner by the developing device 30, and is made into a toner image which is a visible image. By performing the above steps for each of the image forming units PY, PM, PC, and PK, toner images in four colors of yellow, magenta, cyan, and black are formed on each photosensitive drum 10, respectively.

Furthermore, an intermediate transfer belt 15, which is an intermediate transfer member, is arranged below each of the image forming units PY, PM, PC, and PK. The intermediate transfer belt 15 is suspended by rollers 16, 17, and 18, and is movable in the direction of the arrow. The toner images on the photosensitive drum 10 are once sequentially transferred onto an intermediate transfer belt 15, which is an intermediate transfer body, by a transfer roller 13, which is a primary transfer means. As a result, the four-color toner images of yellow, magenta, cyan, and black are superimposed on the intermediate transfer belt 15 to form a full-color image. Further, toner remaining on the photosensitive drum 10 without being transferred is collected by a cleaning device 14.

The full-color image on the intermediate transfer belt 15 is taken out from the sheet cassette 19 and transferred to the sheet S, which is conveyed via the feeding roller 20 and the feeding guide 21, by the action of the secondary transfer roller 25. Toner remaining on the surface of the intermediate transfer belt 15 without being transferred is collected by the intermediate transfer belt cleaning device 22. On the other hand, the sheet S onto which the toner image has been transferred is sent to the fixing device 23, where the image is fixed, and then discharged onto the discharge tray 24.

In this embodiment, the photosensitive drum 10, which is a commonly used drum-shaped organic photoreceptor, is used as the image carrier, but it is of course possible to use an inorganic photoreceptor such as an amorphous silicon photoreceptor. It is also possible to use a belt-shaped photoreceptor. The charging method, transfer method, cleaning method, and fixing method are not limited to the above methods.

[Developing device]
Next, the developing device 30 will be described with reference to FIGS. 2, 3, and 4. First, the longitudinal direction of the developing device 30 is the X axis, the axis perpendicular to the X axis is the axis on the horizontal plane of the axis, the Y axis, and the axis perpendicular to the X axis is the axis on the vertical plane of the axis is the Z axis. shall be. FIG. 2 shows a YZ cross section (the same cross section as FIG. 1) of the developing device, where YZ cross section 1 is approximately at the longitudinal center of the developing device 30, and YZ cross section 2 is outside the image forming area where scattered toner is collected, which will be described later. FIG. 7 is a schematic diagram of the vicinity of a plane passing through a connecting portion between a member 70 and a scattered toner collection port 71; FIG. 3 shows an X-Z cross section of the developing device, where the X-Z cross section 1 is a plane passing through first and second conveyance screws 33 and 34, which will be described later, and the XZ cross section 2 is a direction of the photosensitive drum 10 of the developer container 31. It is a schematic diagram of the vicinity of a plane passing through the center of a first recovery duct 73, which will be described later on the outside. FIG. 4 shows an XY cross section of the developing device, and is also a schematic view of the vicinity of a plane passing through the center of a first recovery duct 73, which will be described later.

The developing device 30 includes a developing container 31 that accommodates a two-component developer, a developing sleeve 32 that is a developer carrier, and first and second conveying screws 33 and 34 that are conveying members. The conveyance screws 33 and 34 are connected to each other by a gear train (not shown), and are driven simultaneously by a conveyance motor. Further, since the developing device 30 of the present embodiment is of a vertical stirring type, the inside of the developing container 31 is approximately at the center thereof, as shown in the YZ cross section 1 in FIG. 2 and the XZ cross section 1 in FIG. The developing chamber 36 and the stirring chamber 37 below the developing chamber 36 are vertically divided by a partition wall 35 extending perpendicularly to the plane of the paper. The developing chamber 36 and the stirring chamber 37 contain a developer and form a circulation path for the developer, as shown in the XZ cross section 1 of FIG. As shown in the Y-Z cross section 1 in FIG. 2, the developing chamber 36 supplies the developer to the developing sleeve 32 (arrow 1 in the Y-Z cross section 1 in FIG. 2), and the stirring chamber 37 supplies the developer from the developing sleeve 32 to the developing sleeve 32. Collect the agent (arrow 2 in YZ cross section 1 in FIG. 2). Further, the developing sleeve 32 rotates while carrying the developer supplied from the developing chamber 36 .

First and second conveying screws 33 and 34 are arranged in the developing chamber 36 and the stirring chamber 37, respectively. The first conveying screw 33 is disposed at the bottom of the developing chamber 36 substantially parallel to the longitudinal direction (rotation axis direction) of the developing sleeve 32, and rotates clockwise in the YZ cross section 1 of FIG. The developer in the developing chamber 36 is conveyed while being stirred in one direction along the axial direction. The reason for the clockwise rotation is that it is advantageous in terms of supplying the developer to the developing sleeve 32. The first conveyance screw 33 has a rotating shaft 33a and a screw blade 33b spirally formed around the rotating shaft 33a, and has a first direction D1 (arrow D1 in the X-Z cross section 1 in FIG. 3). The developer is transported to the Further, the second conveyance screw 34 is disposed at the bottom of the stirring chamber 37 in parallel with the first conveyance screw 33, and rotates in the opposite direction (counterclockwise) to the first conveyance screw 33. Then, while stirring the developer in the stirring chamber 37 in a second direction D2 (arrow D2 in the X-Z cross section 1 in FIG. 3) opposite to the first direction D1, which is the transport direction of the first transport screw 33, transport.

In this way, the developer is circulated between the developing chamber 36 and the stirring chamber 37 through the openings at both ends of the partition wall 35 by being conveyed by the rotation of the first and second conveying screws 33 and 34 (FIG. (in the direction of the arrow on the outside of both ends of the partition wall 35 in the X-Z cross section 1). In this embodiment, a case has been described in which the present invention is applied to the developing device 30 in which the developing chamber 36 and the stirring chamber 37 are arranged one above the other, but the present invention is not limited to this. For example, the present invention is applicable to a conventionally used developing device in which the developing chamber 36 and the stirring chamber 37 are arranged horizontally, or to developing devices of other types. Furthermore, in the present embodiment, a case has been described in which the developing device 30 has a functionally separated configuration in which the function of supplying developer to the developing sleeve 32 and the function of recovering the developer after development are separated. The present invention is not limited to this, and for example, a configuration other than functional separation may be used.

As shown in the YZ cross section 1 of FIG. It is arranged so that it can rotate so that part of it is exposed. The developing sleeve 32 carries and conveys the developer inside the developer container 31 and supplies the developer to the developing position of the photosensitive drum 10 . The length (coat amount) of the developer spikes (magnetic brush) carried by the developing sleeve 32 is regulated by a regulating blade 38 that is a spike cutting member. Here, the distance between the developing sleeve 32 and the photosensitive drum 10 in the closest region (SD gap) is, for example, about 250 μm. As a result, the ears of the developer carried on the developing sleeve 32 and conveyed to the developing position with the length regulated by the regulating blade 38 are brought into contact with the photosensitive drum 10 to form an electrostatic latent image on the photosensitive drum 10. It is set so that it can be developed.

In this embodiment, the support of the developing sleeve 32 has a cylindrical shape with a diameter of 20 mm, and is made of a non-magnetic material such as aluminum or non-magnetic stainless steel, and is made of aluminum in this embodiment. A magnet roller 32m is disposed inside the developing sleeve 32 and is non-rotatably supported by the developing container 31 with a plurality of magnetic poles arranged on its surface.

The magnet roller 32m has a developing pole S2, a regulating pole S1, a transport pole N2, a stripping pole N3, and a pumping pole N1. The developing pole S2 is arranged facing the photosensitive drum 10. The regulation pole S1 is arranged opposite to the regulation blade 38. The pumping pole N1 is arranged on the upstream side in the rotational direction with respect to the regulating pole S1, and pumps up the developer from the developing chamber 36 (arrow 1 in the YZ cross section 1 in FIG. 2). The stripping pole N3 is arranged on the upstream side in the rotational direction with respect to the pumping pole N1, forms a repulsive magnetic field between it and the pumping pole N1, and strips off the developer between the stripping pole N3 and the pumping pole N1 (Fig. 2, Y-Z cross section 1, arrow 2). The transport pole N2 is arranged between the regulation pole S1 and the development pole S2. The magnitude of the magnetic flux density of each magnetic pole is 40 mT to 130 mT.

As described above, the developing sleeve 32 having the magnet roller 32m therein carries and conveys the developer by rotating in the arrow direction (clockwise direction) of the YZ cross section 1 in FIG. 2 during development. Then, the developer whose layer thickness has been regulated by cutting the magnetic brush by the regulation blade 38 is conveyed to a development area facing the photosensitive drum 10, and the developer is applied to the electrostatic latent image formed on the photosensitive drum 10. and develop the latent image.

The regulating blade 38 is made of plate-shaped aluminum or the like and extends along the longitudinal axis of the developing sleeve 32, and is disposed upstream of the photosensitive drum 10 in the rotational direction of the developing sleeve 32. Both the developer toner and the carrier pass between the tip of the regulating blade 38 and the developing sleeve 32 and are sent to the developing position.

By adjusting the gap between the regulating blade 38 and the surface of the developing sleeve 32, the amount of developer carried on the developing sleeve 32 by the magnetic brush is regulated, and the amount of developer conveyed to the developing position is adjusted. be done. In this embodiment, the regulating blade 38 regulates the amount of developer coated per unit area on the developing sleeve 32 to, for example, 30 mg/cm ² . Further, the gap between the regulating blade 38 and the developing sleeve 32 is set to 200 to 1000 μm, preferably 300 to 700 μm. In this embodiment, it is set to 400 μm. Although this embodiment uses a non-magnetic member as the regulating blade 38, a magnetic member may also be used.

In the developing area facing the photosensitive drum 10, the developing sleeve 32 moves in the forward direction of the moving direction of the photosensitive drum 10, and in the normal mode, the developing sleeve 32 moves at a peripheral speed ratio of, for example, 1.7 times that of the photosensitive drum 10. are doing. In this embodiment, the photosensitive drum 10 rotates at a peripheral speed of 348 mm/sec in the normal mode. The developing sleeve 32 rotates at a peripheral speed of 591.6 mm/sec.

The circumferential speed ratio of the developing sleeve 32 to the photosensitive drum 10 is set between 0 and 3.0 times, preferably between 0.5 and 2.0 times, and may be any number of times. . As the moving speed ratio increases, the developing efficiency increases, but if it is too large, problems such as toner scattering and developer deterioration occur, so it is preferable to set it within the above range. In this embodiment, the developing sleeve 32 and the photosensitive drum 10 move in the forward direction (same direction) in the developing area, but the present invention is also applicable to a structure in which the developing sleeve 32 and the photosensitive drum 10 move in the counter direction (in the opposite direction). It is.

The developing sleeve 32 is connected to a high-voltage power source that applies a DC voltage and an AC voltage as a developing bias voltage. On the surface of the developing sleeve 32, negatively charged toner is electrostatically bound to the surface of the positively charged carrier to form magnetic spikes. By creating a potential difference between the developing bias voltage applied to the developing sleeve 32 and the electrostatic latent image on the photosensitive drum 10, the electric field strength formed in the developing area causes the toner to fly onto the photosensitive drum 10 and make the latent image visible. Visualize.

[Developer]
Here, a two-component developer containing toner and carrier used in this embodiment will be explained. The toner has colored resin particles containing a binder resin, a colorant, and other additives as necessary, and colored particles to which an external additive such as colloidal silica fine powder is externally added. There is. The toner is a negatively chargeable polyester resin, and the volume average particle diameter is preferably 3 μm or more and 10 μm or less. More preferably, it is 8 μm or less. In this embodiment, the average particle size of the toner is approximately 6 μm in consideration of image quality and handling properties.

Further, as the carrier, for example, surface-oxidized or unoxidized metals such as iron, nickel, cobalt, manganese, chromium, rare earths, alloys thereof, or oxide ferrite can be suitably used, and these magnetic particles The manufacturing method is not particularly limited. The carrier has a weight average particle diameter of 20 to 60 μm, preferably 30 to 50 μm, and a resistivity of 10 7 Ωcm or more, preferably 10 8 Ωcm or more. In this embodiment, particles of 10 8 Ωcm and a 50% particle diameter (D50) of about 40 μm are used.

In this embodiment, a mixture of this toner and carrier in a weight ratio of 5 to 15% is used. The two-component developer contained in the developing container 31 is stirred while being circulated between the developing chamber 36 and the stirring chamber 37 . The toner and carrier are triboelectrically charged by stirring, and basically a negative charge is given to the toner and a positive charge is given to the carrier. In the two-component developer, the toner and carrier are attached by electrostatic adhesion force generated by this frictional charging and non-electrostatic adhesion force such as Van der Waals force that acts between the toner and carrier.

[Toner supply]
Next, a toner replenishment method in this embodiment will be described. A hopper 40, which is an example of a replenishment device that stores toner and replenishes the developing device 30, is arranged above the developing device 30. The hopper 40 includes a screw-shaped replenishment member 41 at its lower part, and one end of the replenishment member 41 extends to a position of a toner replenishment port 39 provided at the rear side of the developing device 30 . A toner replenishment port 39 for replenishing toner is provided at one end of the developing sleeve 32 in the rotation axis direction, and in this embodiment is provided at the back of the developer container 31 .

As described above, since the latent image is made visible by flying the toner from the developing sleeve 32 to the photosensitive drum 10, the toner of the two-component developer sealed in the developing container 31 is consumed by image formation. The consumed amount of toner passes from the hopper 40 through the toner replenishment port 39 and is replenished into the stirring chamber 34 of the developer container 31 by the conveyance force of the replenishment member 41 and the gravity of the toner. The toner supplied to the stirring chamber 37 joins the developer circulating by the second conveyance screw 34, and is then conveyed through the stirring chamber 37 while being stirred. The amount of toner replenishment is approximately determined by the number of rotations of the replenishing member 41, and this number of rotations is determined by a toner replenishment amount control section (not shown). Methods for controlling the amount of toner replenishment include a method of optically or magnetically detecting the toner density of a two-component developer, a method of developing a reference latent image on the photosensitive drum 10 and detecting the density of the toner image, It is possible to appropriately select a method that uses toner consumption prediction from a printed image. In this embodiment, a sensor for magnetically detecting the toner concentration of the two-component developer is installed in the stirring chamber 37 of the developing device 30.

[Other developing device sensors]
In addition to the sensor for detecting the toner concentration of the two-component developer described above, the developing device 30 may be equipped with a temperature sensor and a humidity sensor for detecting the developer and the surrounding environment. It may also be equipped with a chip that describes manufacturing conditions and various setting values. These sensors and the like are connected to a sensor control section within the main body of the image forming apparatus 1 through cables, connectors, and the like.

[Overview of toner scattering]
Next, toner scattering will be explained. Toner scattering here refers to free toner generated on the surface of the developing sleeve 32 or inside the developing container 31 due to developer agitation, transport, and toner replenishment, passing through the gap between the developing sleeve 32 and the opening of the developing container 31 and developing it. Refers to things that are discharged to the outside of the container 31 and cannot be completely collected into the developing container 31.

First, toner release will be explained. The two-component developer contained in the developing container 31 is stirred while circulating between the developing chamber 36 and the stirring chamber 37 as described above. The surface of the developer is triboelectrically charged by stirring, and the toner adheres to the carrier due to electrostatic adhesion force generated and non-electrostatic adhesion force generated due to surface properties. When an impact or shearing force is applied to the toner adhering to the carrier, if the impact or shearing force is greater than the adhesion force between the toner and the carrier, the toner is peeled off from the carrier and the toner is liberated. At this time, the impact and shearing force that is dominant is due to the behavior of the developer when the developer is transported by the developing sleeve 32. As described above, the developer forms a magnetic spike, which is a chain-like structure along the lines of magnetic force, on the magnetic pole of the developing sleeve 32. The magnetic spike rises forward just before the magnetic pole, and when it passes over the magnetic pole, the magnetic spike tilts forward and falls down. At this time, the direction of rotation of the magnetic ears is the same as the direction of the developing sleeve 32. The toner is peeled off from the carrier due to the impact (inertial force) and centrifugal force when the magnetic spike falls, which is one of the causes of toner release. In addition, impact and inertial force on the developer due to the developer stripping operation performed between the stripping pole N3 and the pumping pole N1 and the agitation conveyance operation by the conveyance screws 33 and 34 among the developer behavior caused by the developing sleeve 32 can also be caused. Toner release occurs.

Further, when toner is replenished from the toner replenishment port 39, the toner that flies up before being sufficiently stirred in the stirring chamber 37 and the developing chamber 36 also becomes a cause of free toner in the developing container 31. As described above, the toner supplied at the toner supply port 39 is stirred with the developer already in the stirring chamber 37 and conveyed. At this time, the toner-developer mixing ratio temporarily increases in the area where the supplied toner and developer are mixed. When the toner-developer mixing ratio is high, the amount of charge on the toner decreases, and the electrostatic adhesion between the toner and the carrier decreases. The replenishment toner that has not been completely mixed with the developer may be released as it is or by the impact of stirring and transporting the developer by the first and second transport screws 33 and 34, and the free toner may fly up inside the developer container 31. Are known.

The YZ cross section 1 in FIG. 2 also shows the airflow around the developing device 30. The main causes of the airflow generated near the developing section are the rotation of the developing sleeve 32 and the rotation of the photosensitive drum 10. First, as the developing sleeve 32 rotates, an airflow A is generated in the same direction as the developing sleeve 32 rotates. As the developing sleeve 32 rotates, the airflow A is introduced into the developing container 31 from a gap located on the downstream side of the developing sleeve 32 in the direction of rotation of the developing section. The airflow A contains toner released by the impact (inertial force) and centrifugal force when the magnetic ears fall down. When the air pressure inside the developer container 31 is balanced, an airflow B having substantially the same flow rate as the airflow A is discharged from a gap in the developer container 31 located on the downstream side of the developer sleeve 32 in the direction of rotation of the developing section.

The airflow B is a mixture of a part of the airflow A that is turned back and discharged as it is, and a part of the airflow that is discharged from the inside of the developer container 31. The airflow discharged from inside the developing container 31 includes free toner generated by the developer stripping operation by the developing sleeve 32, stirring and conveying operation by the conveying screws 33 and 34, and toner liberated due to the influence of toner replenishment. . The airflow B discharged from the gap of the developer container 31 basically flows between the developer container 31 and the photosensitive drum 10 in a direction following the rotational direction of the developer sleeve 32 (downward in the YZ cross section 1). Since this airflow B contains free toner as described above, there is a possibility that the inside of the image forming apparatus 1 will be contaminated if left as is. As a countermeasure against this, a scattered toner collection member 70 is provided at the bottom of the developer container 31.

The scattered toner collecting member 70 is disposed along the longitudinal direction of the developing sleeve 32 as shown in the XY cross section of FIG. It is arranged on the downstream side in the rotational direction of the developing sleeve 32 along the gap between the developing sleeve 32 and the developing sleeve 32 . This scattered toner collection member 70 has the role of making it easier to return the discharged airflow B to the vicinity of the developing section again, and collecting and collecting toner that separates from the airflow B and falls due to inertial force. Since the airflow B is generated along the entire length of the developing sleeve 32, it is desirable that the scattered toner collecting member 70 is longer than the opposing developing sleeve 32 in the longitudinal direction. In this embodiment, the scattered toner collecting member 70 is installed to be longer than the developing sleeve 32 by 5 mm at both ends.

The airflow B that has passed near the scattered toner collecting member 70 basically returns to the vicinity of the developing area. This means that the airflow near the downstream side of the developing section includes the airflow A, the airflow B, the airflow D generated by the rotation of the photosensitive drum 10, and the airflow C that supplies air from between the developer container 31 and the photosensitive drum 10 toward the development section. It is constructed so that it matches. The scattered toner transferred from the airflow B to the airflow D due to inertial force also causes contamination of the inside of the image forming apparatus 1.

As described above, the collected scattered toner continues to accumulate on the scattered toner collecting member 70 due to the airflow B discharged from the developer container 31 containing toner (accumulated toner in the YZ cross section 1 in FIG. 2). Since the space created by the developer container 31 and the scattered toner collecting member 70 is limited, as the developing device 30 has a long service life and is used for image formation, the space may eventually exceed the allowable accumulation amount and the scattered collected toner may overflow. In that case as well, there is a risk that the inside of the image forming apparatus 1 may be contaminated.

[Scattered toner collection duct]
Therefore, as shown in the YZ cross section 2 of FIG. 2, a scattered toner collection port 71 is formed at the longitudinal end of the space created by the developer container 31 and the scattered toner collection member 70, and As shown in FIG. 2, a suction and collection mechanism 72 for suctioning and collecting scattered toner is provided within the main body of the image forming apparatus 1. Furthermore, a first collection duct 73 is fixed to the developing device 30 and connected to the scattered toner collection port 71, and a second collection duct 73 is fixed to the main body of the image forming apparatus 1 to connect the suction collection mechanism 72 and the first collection duct 73. A collection duct 74 is provided to prevent suction airflow and collected toner from leaking at the joint between the second collection duct 74 on the main body side of the image forming apparatus 1 and the first collection duct 73 on the developing device 30 side. An elastic member is provided as a seal member 77.

The scattered toner recovery port 71 may be provided at either the front or the back of the developing container 31. In this embodiment, the toner recovery port 71 is provided at the back of the developing container 31, close to the supply port 39. As mentioned above, developer containing toner immediately after supply tends to generate free toner in the developing container 31 due to insufficient mixing time. Therefore, by providing the scattered toner recovery port 71 at the back where the toner supply port 39 is located, scattered toner can be collected more efficiently.

FIG. 5 shows an enlarged view of the joint between the first recovery duct 73 on the developing device 30 side and the second recovery duct 74 on the main body side of the image forming apparatus 1. FIG. 5 is an enlarged view of the vicinity of the seal member 77 taken along the XZ cross section 2 in FIG. The scattered toner collection port 71 of this embodiment has an opening of 6 mm x 8 mm, and is in contact with the back end of the scattered toner collection member 70 at a position 5 mm from the end of the developing sleeve 32, and is connected to the developer container 31 and the scattered toner collection member. It is installed at the longitudinal rear end of the space created by 70. The first recovery duct 73 has a rectangular cylindrical shape with cross-sectional dimensions of 6 mm x 8 mm and is fixed to the developer container 31 . The second recovery duct 74 also has a rectangular cylindrical shape with cross-sectional dimensions of 6 mm x 8 mm, and is fixed to the main body of the image forming apparatus 1. The ends of the first recovery duct 73 and the second recovery duct 74 are designed to have a width of 1 mm (corresponding to d in FIG. 5) when connected, and a urethane sponge is provided as a sealing member 77. The urethane sponge is fixed with double-sided tape to the end of the first collection duct 73 facing the second collection duct 74, with a thickness of 3 mm (corresponding to D in Fig. 5) and a pasting margin of 3 mm. It is formed along the shape of the end of the duct 73. As mentioned above, since the ends of the first recovery duct 73 and the second recovery duct 74 are 1 mm apart when connected, the urethane sponge is installed with a crushing margin of 2 mm, and the first recovery duct 73 and the second recovery duct 74 are There will be a slight bulge at the joint of the recovery duct 74.

The suction collection mechanism 72 is connected to the second collection duct 74 and includes a toner filter 75 and a suction fan 76 made of a centrifugal fan. The suction collection mechanism 72 is connected to a second collection duct 74 and connected to the scattered toner collection port 71 through a first collection duct 73 connected to the second collection duct 74 . As a result, a suction airflow E (YZ section 2 in FIG. 2, XZ section 2 in FIG. 3) is generated in the longitudinal direction of the space created by the developer container 31 and the toner collection member 70, and the airflow B and The scattered toner collected by the toner collection member 70 is sucked. The filter 75 is replaceable and is provided on the upstream side when viewed from the scattered toner collection airflow of the suction fan 76, and collects the collected scattered toner. During maintenance, the toner filter 75 is replaced. In this embodiment, the suction force of the suction collection mechanism 72 is set so that the flow rate of the scattered toner collection port 71 is 0.01 m ³ /min in the image formation standby state. Further, the toner filter 75 uses a nonwoven fabric filter that can capture particles of about 6 μm.

Note that this is just an example, and the structure for collecting scattered toner is not limited to this. For example, the filter structure may be an electric field filter, a cyclone type filter, or the like. Further, the blowing configuration may be an axial fan or a compressor.

[Toner falling when replacing the developing device]
As described above, a seal member 77 is installed at the joint of the second recovery duct 74 at the end of the first recovery duct 73 to prevent the recovery airflow and recovery toner from leaking. Similar to FIG. 5, FIG. 6 is the same plane as the XZ cross section 2 of FIG. Further, circles in FIG. 6 indicate accumulated toner. As shown in FIG. 6, since the parts and shape of this part are different from those around the inside of the collection duct 73, airflow inside the collection ducts 73 and 74 causes turbulence, and scattered toner is deposited near this seal member 77. do. When replacing the developing device 30, in order not to damage the photosensitive drum 10 facing the developing sleeve 32, move the developing device 30 one end in the direction away from the photosensitive drum 10 as shown in FIG. There is also a method as shown in FIG. 8 in which the developing device 30 and the photosensitive drum 10 are pulled out from the main body of the image forming apparatus 1 and then the developing device 30 and the photosensitive drum 10 are separated. Similar to FIG. 4, FIGS. 7 and 8 are enlarged views of the vicinity of the seal member 77 on the XY plane.

In this embodiment, the former separation method is adopted, in which the developing device 30 is moved 10 mm in the direction of separating it from the photosensitive drum 10, and then the developing device 30 is pulled out from the image forming apparatus 1. If the former method is used, when the developing device 30 is separated from the photosensitive drum 10, if the latter method is used, the developing device 30 and the photosensitive drum 10 are removed from the main body of the image forming apparatus 1. The second collection duct 74 is separated. As shown in FIG. 6, when the second recovery duct 74 at the end of the first recovery duct 73 separates, in addition to the impact of the separation operation, a restoring force is generated when the compressed seal member 77 is released. As a result, the accumulated toner near the compressed seal member 77 is crushed. In this state, when the second collection duct 74 at the end of the first collection duct 73 is separated, the accumulated toner falls from the spaced gap.

When this accumulated toner falls within the image forming apparatus 1, it causes image defects due to toner contamination in the optical system and image forming section, and causes drive operation defects in the drive section. If it falls outside the image forming apparatus 1, it may stain the floor or the like. Therefore, in the image forming apparatus 1 using the developing device 30 having the suction collection mechanism 72 and the scattering collection ducts 73 and 74, it is necessary to reduce the falling of the accumulated toner as much as possible.

[Measures to prevent toner from falling when replacing the developing device]
Now, countermeasures against toner falling when replacing the developing device in this embodiment will be explained. As described above, in order to prevent the collected toner accumulated on the inner wall of the collection duct 73-suction collection mechanism 72 from falling when the collection duct 73 and the suction collection mechanism 72 are separated when the developing device is replaced, it is necessary to close the first collection duct 73 end. It is effective to have the suction collection mechanism 72 collect the toner deposited on the second collection duct 74 and the seal member 77 therebetween. Therefore, in this embodiment, as shown in FIG. 9, it is proposed that the suction and recovery mechanism 72 continue to suck when the developing device 30 is replaced. FIG. 9 is the same cross section as FIG. 6, with ◯ indicating accumulated toner and arrows indicating airflow E.

First, it is assumed that the total number of sheets printed by the image forming apparatus 1 has increased and the developing device 30 needs to be replaced for some reason. In this case, the user or the system administrator of the image forming apparatus 1 is notified that the developing device 30 needs to be replaced using an alert or the like. Here, an operation section with a monitor attached to the main body of the image forming apparatus 1 is used, in which an operation input section of the image forming apparatus 1 and a display section for displaying the status of the image forming apparatus 1, alerts, etc. are integrated. However, the operation input section and display section are not limited to this, and the input section may be a numeric keypad, a switch, etc., and the display section may be a lamp display. Alternatively, it may be an external input/output device such as a connected PC. A replacement person who receives the notification of replacement of the developing device 30 prepares a replacement developing device 30. In this state, the power of the image forming apparatus 1 is turned on and the image forming apparatus 1 is placed in an image forming standby state (STEP 0).

A block diagram related to this proposal beyond this point is shown in FIG. 10, a sequence is shown in FIG. 11, and a timing chart corresponding to FIG. 11 is shown in FIG.

In the image forming standby state, the replacement person changes the operating mode of the image forming apparatus 1 to the developing device replacement mode using the operation unit (STEP 1). At this point, the display unit displays that the developing device 30 cannot be replaced (for example, a message such as "Processing" or "Please wait") is displayed on the display unit.

The control section of the image forming apparatus 1 monitors the mode, and when it is confirmed that the developing device replacement mode is set by the operator's operation, the control section of the image forming apparatus 1 monitors the mode, and when it is confirmed that the developing device replacement mode is set by the operation of the replacement person, the control section of the image forming apparatus 1 changes the sensor related to the developing device 30, the drive and high voltage related to image formation. Turn off the power (STEP 2). This is to prevent the replacement person from receiving an electric shock due to malfunction of the high-voltage power supply of the image forming apparatus 1, to prevent the replacement person from being caught or caught in the mechanical drive due to malfunction of the drive section of the image forming apparatus 1, and to prevent equipment failure. This is to prevent sensor failure due to overcurrent that occurs when connectors of sensors attached to the developing device 30, such as the developer concentration sensor, are connected or disconnected in a later process.

In this state, the image forming apparatus 1 displays on the display unit that the developing device 30 is replaceable (STEP 3). Thereafter, the display unit displays a message to input a replacement completion signal after replacing the developing device 30, and the control unit monitors the replacement completion signal.

After confirming that the developing device 30 is replaceable, the replacement person removes the exterior of the image forming device 1 to make the developing device 30 accessible. First, disconnect the connectors of the sensors. Next, the developing device 30 is moved in a direction away from the photosensitive drum 10. At this time, in the conventional configuration in which this embodiment is not adopted, the toner accumulated on the second collection duct 74 at the end of the first collection duct 73 and the seal member 77 between them falls as described above (Fig. 6 ). When the proposal of this embodiment is adopted, as shown in FIG. 9, the accumulated toner crushed by the impact of the separating operation and the restoring force when the seal member 77 is released can be sucked and collected by the suction recovery mechanism 72. Thereafter, the developing device 30 is pulled out of the image forming apparatus 1. The new and old developing devices 30 are replaced by installing a replacement developing device by performing the reverse operation of the above procedure (STEP 4).

The person who replaced the developing device 30 inputs a replacement completion signal for the developing device 30 using the operation section (STEP 5).

The control unit of the image forming device 1 energizes the sensors related to the developing device 30 that were shut off in STEP 2, as well as the drive and high-voltage power supplies related to image formation (STEP 6).

After the sensors and power supply are restored and normal operation is confirmed, an initialization sequence for the developing device 30 is performed (STEP 7). After the initialization sequence of the developing device is completed, the process returns to the normal image forming standby state, and the display unit notifies the completion of the developing device replacement sequence (STEP 8).

The above is the sequence of replacing the developing device 30 proposed in this embodiment. With the above measures, it is possible to reduce the amount of toner in the collection duct 73, especially in the vicinity of the joint, and to reduce the amount of toner accumulated in the second collection duct 74 at the end of the first collection duct 73 and the seal member 77 therebetween. Falling can be reduced.

<Second embodiment>
In the first embodiment, by driving the suction collection mechanism 72 when replacing the developing device 30, the toner accumulated on the second collection duct 74 at the end of the first collection duct 73 and the seal member 77 therebetween is suctioned and collected. However, the collected toner was sucked into the mechanism 72 to prevent it from falling. In this embodiment, a configuration is proposed in which the collected toner can be more effectively sucked into the suction collection mechanism 72.

Normally, toner scattering from the developing device 30 increases when the image forming apparatus 1 is started up or when forming an image. Therefore, the maximum value of the suction force of the suction and collection mechanism 72 is determined based on the time of startup and image formation. On the other hand, during image formation standby, the developing sleeve 32 is not rotating and the amount of toner scattering is small. Therefore, if the suction force remains unchanged during startup or image formation, it will become excessive for the scattering suction during image formation standby. Furthermore, during start-up and image formation, there are many moving parts, so the operating noise is loud, but when the image is on standby, the operating noise is low. Therefore, the operation noise of the suction fan 76 of the suction recovery mechanism 72 tends to be noticeable. Therefore, from the viewpoint of power consumption and quietness, the suction force of the suction and collection mechanism 72 during image formation standby is often set to be smaller than that at startup or image formation, or to zero. In other words, the suction force of the suction and collection mechanism 72 during image formation standby often has some margin. In fact, the suction force of the suction recovery mechanism 72 used in this embodiment is also the same, and as described above, the suction force is adjusted so that the flow rate of the scattered toner recovery port 71 is 0.01 m ³ /min in the image forming standby state. However, during image formation, the maximum flow rate of the scattered toner collection port 71 is set to 0.03 m ³ /min. Wind pressure P due to airflow is expressed by the following formula.

P=0.5×ρ×V^2...(Formula 1)
Here, ρ is the air density and V is the reference wind speed. According to this formula, wind pressure is proportional to the square of wind speed (∝flow rate). Therefore, the toner recovery effect can be estimated as the square of the flow rate.

Therefore, in this embodiment, as shown in FIG. 13, by increasing the suction force of the suction and collection mechanism 72 when replacing the developing device 30 compared to when waiting for image formation, the suction force at the end of the first collection duct 73 is more effectively It is proposed that the toner accumulated on the second collection duct 74 and the seal member 77 therebetween be sucked into the suction collection mechanism 72.

The main body structure and problems of this embodiment are the same as those of the first embodiment. Therefore, the description of this embodiment will be based on the sequence of replacing the developing device 30 proposed in this embodiment.

First, as in Embodiment 1, the use of the image forming apparatus 1 progresses, and the person who replaces the developing apparatus 30 who receives the notification of replacement prepares the developing apparatus 30 for replacement, turns on the power of the image forming apparatus 1, and enters the image forming standby state. (STEP 0).

As in Embodiment 1, in the image forming standby state, the person replacing the image forming apparatus 1 changes the operating mode of the image forming apparatus 1 to the developing device replacement mode using the operation unit (STEP 1).

The sequence of this embodiment is shown in FIG. 14, and the timing chart corresponding to FIG. 14 is shown in FIG.

The control section of the image forming apparatus 1 monitors the mode, and when it is confirmed that the developing device replacement mode is set by the operation of the replacement person, the control section of the image forming apparatus 1 monitors the mode, and when it is confirmed that the developing device replacement mode is set by the operator's operation, the control section of the image forming apparatus 1 changes the sensor related to the developing device 30, the drive and high voltage related to image formation. Cut off the power. Furthermore, the control unit increases the suction force of the suction and collection mechanism 72 to be greater than that in the image forming apparatus standby state. In this embodiment, the flow rate of the scattered toner collection port 71 is changed from 0.01 m ³ /min in the image forming apparatus standby state to 0.03 m ³ /min, which is the maximum output, during the image forming standby state (STEP 2). As shown in FIG. 13, with this change, part of the toner that could not be suctioned at the flow rate of 0.01 m ³ /min in the image forming apparatus standby state is collected by the suction collection mechanism 72.

In this state, the image forming apparatus 1 displays on the display unit that the developing device 30 is replaceable (STEP 3). Thereafter, the display unit displays a message to input a replacement completion signal after replacing the developing device 30, and the control unit monitors the replacement completion signal.

After confirming that the developing device 30 is replaceable, the replacement person replaces the old and new developing device 30 using the same procedure as in the first embodiment (STEP 4). In this embodiment, the suction force is larger than that in Embodiment 1, so that the accumulated toner crushed by the impact of the separating operation and the restoring force when the sealing member 77 is released can be more efficiently collected by suction, as shown in FIG. mechanism 72.

The person who replaced the developing device 30 inputs a replacement completion signal for the developing device 30 using the operation section (STEP 5).

The control unit of the image forming apparatus 1 energizes the sensors, drives and high-voltage power sources related to the developing device 30 that are shut off in STEP 2 and that are related to image formation (STEP 6).

After the sensors and power supply are restored and normal operation is confirmed, an initialization sequence for the developing device 30 is performed (STEP 7).

After the initialization sequence of the developing device is completed, the suction force of the suction recovery mechanism 72 that was increased in STEP 2 is returned to the value of the image forming standby state, and the normal image forming standby state is returned, and the completion of the developing device replacement sequence is notified on the display ( STEP 8).

The above is the sequence of replacing the developing device 30 proposed in this embodiment. The above measures can further increase the effect of reducing toner inside the recovery duct 73, especially in the vicinity of the joint, and prevent toner from accumulating on the second recovery duct 74 at the end of the first recovery duct 73 and the seal member 77 therebetween. Falling of toner can be further reduced.

<Third embodiment>
Although the configurations of Embodiments 1 and 2 have a high ability to collect the toner accumulated in the second recovery duct 74 at the end of the first recovery duct 73 and the seal member 77 between them, the configuration of the embodiment Since the work is carried out without any changes, there remains a slight risk of an accident for the replacement person or a failure of the equipment due to the above-mentioned malfunction. Therefore, we would like to propose a configuration in which the accumulated toner can be collected while ensuring safety by turning off the main body power of the image forming apparatus 1 when the developing device 30 is inserted or removed, as in the past.

As shown in equation 1 of the second embodiment, the ability to collect toner accumulated in the second collection duct 74 at the end of the first collection duct 73 and the seal member 77 between them is determined by the air generated by the suction collection mechanism 72. It is proportional to the square of the flow rate. In other words, as shown in FIG. 16, by collecting the accumulated toner at a larger flow rate than during image formation before inserting and removing the developing device 30, the second collection duct 74 at the end of the first collection duct 73 and The developing device 30 can be inserted and removed while the amount of toner accumulated on the seal member 77 between them is small.

Normally, the output of the suction fan 76 of the suction and recovery mechanism 72 during image formation is determined by power consumption, fan operating noise, and the like. This time, if suction is performed at a large flow rate only when replacing the developing device 30, there is a high possibility that power consumption and operational noise will not be a problem because the work is irregular. Therefore, a suction fan 76 whose maximum output is larger than usual is used, and the suction fan 76 is used when the output is less than 100% during normal image formation. In this embodiment, the maximum flow rate of the scattered toner collection port 71 is changed from 0.03 m ³ /min to 0.05 m ³ /min. This made it possible to increase the toner recovery capacity by about 2.8 times.

The sequence of this embodiment is shown in FIG. 17, and a timing chart corresponding to FIG. 17 is shown in FIG.
First, as in Embodiments 1 and 2, the use of the image forming apparatus 1 progresses, and the person who replaces the developing apparatus 30 who receives the notification for replacement prepares the developing apparatus 30 for replacement, turns on the power of the image forming apparatus 1, and forms an image. It is assumed that the computer is in a standby state (STEP 0).

As in the first embodiment, while the image forming apparatus is in a standby state, the person replacing the image forming apparatus 1 changes the operating mode of the image forming apparatus 1 to the developing device replacement mode using the operation unit (STEP 1). At this point, the display section displays that the developing device 30 will be replaced after the main power of the image forming apparatus 1 is shut off (for example, a message such as ``Please replace the developing device after the main body is stopped'') is displayed.

The control section of the image forming apparatus 1 monitors the above mode, and when it is confirmed that the developing device exchange mode is set by the operation of the exchanger, the control section sets the suction force of the suction recovery mechanism 72 to change the mode during image formation. Make it bigger. In this embodiment, the flow rate of the scattered toner collection port 71 is changed from 0.01 m ³ /min during image formation standby to 0.05 m ³ /min, which is the maximum output (STEP 2).

In this state, after suction is carried out for a certain period of time, the control unit 50 shuts off the main power of the image forming apparatus 1 (STEP 3).

After confirming that the main power source of the image forming apparatus 1 has been shut off, the replacement person replaces the new and old developing devices 30 in the same manner as in Embodiments 1 and 2 (STEP 4).

The person who replaced the developing device 30 turns on the main power of the image forming apparatus 1 (STEP 5).

The control unit of the image forming apparatus 1 starts image forming and checks various sensors and power sources (STEP 6).

After the sensors and power supply are restored and normal operation is confirmed, an initialization sequence for the developing device 30 is performed (STEP 7).

After the initialization sequence of the developing device is completed, the developing device replacement mode is returned to the normal image forming standby state, and the completion of the developing device replacement sequence is notified on the display unit (STEP 8).

The above is the sequence of replacing the developing device 30 proposed in this embodiment. With the above measures, it is possible to further reduce the falling of toner accumulated on the second collection duct 74 at the end of the first collection duct 73 and the seal member 77 between them, while ensuring the same safety as before. can.

In each of the embodiments described above, a case has been described in which a two-component developer is applied, but the present invention is not limited to this, and the present invention can also be applied to an image forming apparatus 1 that uses a one-component developer.

1 Image forming device 10 Photosensitive drum (image carrier)
11 Charger 12 Laser beam scanner (exposure means)
13 Transfer roller 15 Transfer belt 14 Cleaning device 23 Fixing device 30 Developing device 31 Developing container 32 Developing sleeve (developer carrier)
32m Magnet roller 33 First conveyance screw (conveyance member)
34 Second conveyance screw (stirring member)
35 Partition wall 36 Developing chamber 37 Stirring chamber 38 Regulation blade 39 Toner replenishment port 40 Hopper (replenishment device)
41 Supply member 70 Scattered toner collection member 71 Scattered toner collection port 72 Suction collection mechanism 73 First collection duct 74 Second collection duct 75 Toner filter 76 Suction fan 77 Seal member 50 Control section

Claims (7)

an image carrier, a developer container containing a developer, a transport member that agitates and transports the developer contained in the developer container, a developer carrier that rotates while carrying the developer, the image carrier and the a scattered toner collecting section disposed on the downstream side in the rotational direction of the developer carrying member along a gap with the developer carrying member; and a collecting duct connected to the scattered toner collecting section; a developing device that develops an electrostatic latent image formed on the body using a developer carried on the developer carrier; and a developing device that is connected to the collection duct and that collects toner collected in the scattered toner collection section or floating in the scattered toner collection section. An image forming apparatus comprising: a blower mechanism that sucks the toner together with nearby air;
The image forming apparatus is characterized in that the air blowing mechanism is operated in at least a part of the developing device replacement process to suck the toner collected into the collection duct and the scattered toner collection section. In the step of removing the developing device to be replaced from the main body of the image forming apparatus in the step of replacing the developing device, the air blowing mechanism is operated to suck the toner collected into the collecting duct and the scattered toner collecting section. 1. The image forming apparatus according to 1. 3. The image forming apparatus according to claim 1, wherein in the step of replacing the developing device, suction generated by the air blowing mechanism is made larger than suction during normal image printing standby. The image forming apparatus includes an input section through which a person replacing the developing device can input information, a display section that displays the status of the image forming apparatus to the person replacing the developing device, and a developing device that the person replacing the developing device can select at the input section when replacing the developing device. The apparatus has a device exchange mode, and the timing at which the suction generated by the air blowing mechanism is made larger than the suction during normal image printing standby indicates that the developing device can be replaced after the developing device exchange mode is selected. 4. The image forming apparatus according to claim 1, wherein the image forming apparatus is somewhere between. The timing for returning the suction generated by the air blowing mechanism to the suction during normal image printing standby is from when the input section detects that the replacement person has completed replacing the developing device until the end of the developing device replacement mode. The image forming apparatus according to any one of claims 1 to 4, wherein the image forming apparatus is somewhere between. 6. The image forming apparatus according to claim 1, wherein in the step of replacing the developing device, suction generated by the air blowing mechanism is made larger than suction during normal image printing. In the step of replacing the developing device, before the step of removing the developing device to be replaced from the main body of the image forming apparatus, the blowing mechanism is operated to suck the toner collected into the collecting duct and the scattered toner collecting section. The image forming apparatus according to any one of claims 1 to 6.