JP2003255788A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely prevent various bad conditions caused by the increase of dust by stably detecting the quantity of the dust floating in an apparatus. <P>SOLUTION: At a developing area for developing a latent image on a photoreceptor drum, a primary transferring part, etc., spattered toner is produced. The spattered toner produced at the developing area, the primary transferring part, etc., is placed on an air flow made by a suction fan 351 and sucked into the inside of a development duct 310, a primary transferring duct 320, etc. Then, after detecting the quantity of the sucked spattered toner by a dust quantity detection sensor 370, the spattered toner is recovered by a dust collection filter 352. Since the detected toner is distributed properly compared with that in a floating state, the quantity of the spattered toner produced at the developing area, the primary transferring part, etc., can stably be detected. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, etc.
The present invention relates to an image forming apparatus that develops a latent image on a latent image carrier with a developer and records the formed toner image on a recording material to form an image.

[0002]

2. Description of the Related Art As an image forming apparatus of this kind, a latent image on a latent image carrier is developed by a developing device with a developer, and a toner image formed thereby is transferred onto a recording material to form an image. An electrophotographic image forming apparatus is known. In such an image forming apparatus, various contrivances have heretofore been made to prevent the toner in the developer from scattering in the machine as much as possible. However, when the developer is deteriorated, the environment is changed, or a trouble occurs in the control system, the toner may be scattered in the machine, and the scattered toner may float in the machine. In addition to such scattered toner, additives in the developer such as toner and carrier, lubricant applied to the photosensitive drum as a latent image carrier and the intermediate transfer belt as an image carrier, etc. May float on.

Usually, dust such as scattered toner, additives, lubricants, etc. floating in the machine is collected by a dust collecting means in which a dust collecting filter is attached to an exhaust fan for discharging the air inside the machine to the outside. . However, if the amount of dust floating in the machine increases, the dust may not be collected completely, and the dust may stain the optical system in the machine, or the transfer paper as a recording material may have a background stain. Further, due to the dust that could not be collected completely, a drive failure of a gear used in the drive system of the image forming apparatus occurs, which causes a drive unevenness trace called banding to appear in the image and deteriorates the image quality. May occur. Furthermore, if the amount of dust floating inside the machine increases, a large amount of dust will adhere to the dust collection filter attached to the exhaust fan, and the air circulation inside the machine will deteriorate.
The collection capability for collecting dust inside the machine is reduced, and the above-mentioned problems due to dust are likely to occur. Further, when the air circulation in the machine deteriorates in this way, the temperature inside the machine abnormally rises and the developer solidifies, which may cause a problem that the developing device cannot be driven.

[0004]

In order to prevent such a problem from occurring, the amount of dust floating in the machine is accurately detected, and based on the detection result, an operator such as a user or a management center can appropriately detect the amount of dust. Need to be processed. recent years,
As a system for informing an operator or the like of the detection result of the amount of dust, a remote diagnosis system has been proposed for informing various parameters indicating the state of the image forming apparatus to an operator or the like at a place away from the site where the image forming apparatus is installed. . For example, Japanese Patent No. 3019358 discloses a copying machine management apparatus that transmits parameters such as the amount of toner adhered on a photoconductor in a copying machine from the copying machine to a centralized management apparatus of a management center. If such a remote diagnosis system is adopted, the amount of dust increased inside the machine can be grasped by the operator etc. at an early stage, so various problems due to the increase in dust amount can be prevented and the image quality can be stabilized for a long time. Can be achieved. However, dust floating in the image forming apparatus is generated in various places in the apparatus. In particular, toner scattering, which is a cause of scattered toner that occupies most of the dust, occurs not only in the developing device but also in the transfer portion that transfers the toner image, and the toner image carried on the image carrier is conveyed. It can occur inside. Therefore, the above patent No. 30
As in the copier management apparatus disclosed in Japanese Patent No. 19358, the operator cannot grasp the total amount of dust floating in the machine if the parameters transmitted to the management center are only the toner adhesion amount on the photoconductor. It was Therefore, the above copying machine management device may not be able to prevent various problems caused by an increase in dust.

Further, since most of the dust floating in the machine is toner scattered from the developing device, it has been conventionally devised to reduce the amount of the toner scattered as much as possible to prevent various problems due to the dust. Various image forming apparatuses have been proposed.

For example, it is known that the amount of background stain on the photosensitive drum is detected by an optical sensor, and when the background stain increases, the toner concentration in the developer is reduced to suppress toner scattering. However, this image forming apparatus does not directly detect the toner scattering amount, and therefore the toner concentration is not controlled based on the accurate toner scattering amount. Therefore, even this image forming apparatus may not be able to prevent various problems caused by an increase in dust.

Further, Japanese Patent No. 3140329 discloses that
An image forming apparatus has been disclosed in which a toner scattering detection unit is arranged immediately below the developing device, specifically, below the toner supply opening in the developing device housing, and the amount of toner scattering from the developing device is detected. . This image forming apparatus suppresses toner scattering by controlling the developer agitating operation and the toner replenishing operation of the developing device according to the toner scattering amount detected by the toner scattering detecting unit including an optical sensor. However, the image forming apparatus disclosed in Japanese Patent No. 3140329 has a configuration in which the optical sensor is arranged immediately below the developing device in which toner scattering easily occurs. In the area immediately below the developing device, the airflow is weak and the scattered toner is in a floating state, and the scattered toner easily adheres to the optical sensor. Therefore, there is also a problem that the optical sensor is easily soiled and it is difficult to realize stable detection. Further, the behavior of the scattered toner is unstable in the region directly below the developing device. Therefore, even if an optical sensor is arranged immediately below the developing device to detect the amount of toner scattering, it is difficult to realize stable detection.

The present invention has been made in view of the above problems, and an object of the present invention is to realize stable detection of the amount of dust floating in the machine and to accurately check various problems caused by the increase of dust. Another object of the present invention is to provide an image forming apparatus capable of preventing the above.

[0009]

In order to achieve the above object, the invention of claim 1 develops a latent image on a latent image carrier with a developer, and records the formed toner image on a recording material. In the image forming apparatus for forming an image, dust collecting means for collecting dust generated inside the machine, air flow generating means for generating an air flow for transporting the dust to the dust collecting means, and dust by the air flow And a dust amount detecting means for detecting the amount of dust in the dust path through which the toner is conveyed. According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, there is provided dust passage forming means for forming a dust passage, which is a part of the dust passage, and the dust amount detecting means includes the dust passage. The feature is that the amount of dust is detected in the passage. According to a third aspect of the invention, in the image forming apparatus according to the second aspect, the dust passage forming means is
Form at least two dust passages on the downstream side,
The dust amount detecting means is characterized by detecting the amount of dust in a part of a branch passage portion of the dust passage. According to a fourth aspect of the present invention, in the image forming apparatus according to the second aspect, the dust passage forming means forms a plurality of dust passages in which entrances of the dust passages are open at different positions in the machine, The dust amount detection means is characterized by detecting the amount of dust in at least one of the plurality of dust passages. According to a fifth aspect of the invention, in the image forming apparatus according to the second aspect, the dust passage forming means is
The inlets of the dust passages are opened at different positions in the machine, and the passages extending from the respective inlets form a confluent dust passage. It is characterized by detecting the quantity. Further, the invention of claim 6 is
In the image forming apparatus of 3, 4 or 5, the determination means determines whether or not the amount of dust in the dust path exceeds a predetermined amount based on the detection result of the dust amount detection means, and the determination means. It is characterized by having an informing means for informing when it is determined that the predetermined amount has been exceeded. In the image forming apparatus according to the first to sixth aspects, the airflow generating means generates the airflow for conveying the dust generated inside the machine to the dust collecting means. As a result, the dust is carried by the air flow to the dust collecting means. Then, in the image forming apparatus, the dust amount detecting means detects the amount of dust in the dust path through which the dust is conveyed by the air flow. The detected dust is flowing in a predetermined direction and is in an appropriately dispersed state as compared with the dust in a floating state. Therefore, the detected dust is the above-mentioned Japanese Patent No. 314.
The dust density is lower than that of the image forming apparatus disclosed in Japanese Patent No. 0329,
Moreover, since it is in the state of being carried by the air flow, it is difficult for dust to adhere to the dust amount detecting means. Further, since the dust amount detecting means detects the amount of dust flowing in the predetermined direction by riding the air flow as described above, the behavior of the detected dust is more stable than the dust in the floating state. Therefore, in this image forming apparatus,
It is possible to detect the amount of dust with respect to dust that exhibits stable behavior. It should be noted that the dust path along which the dust is conveyed by the airflow may be a path along which the dust is carried to the dust collecting means by riding on the airflow generated by the airflow generating means. Therefore, it is not limited to the passage formed in the duct, and includes, for example, a path during which dust existing in the machine is conveyed to the duct inlet by the air flow.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter simply referred to as "copying machine") as an image forming apparatus will be described below. The copying machine of the present embodiment is a so-called tandem type color copying machine provided with a photosensitive drum as a latent image carrier for each color, but the present invention is not limited to this.

First, the configuration of the entire copying machine according to this embodiment will be described. FIG. 2 is a schematic configuration diagram of the entire copying machine according to the present embodiment. This copying machine has a copying machine body 10
0 and a paper feed table 200 on which the main body of the copying machine is placed
And a scanner 300 mounted on the main body of the copying machine,
It is composed of an automatic document feeder (ADF) 400 attached to the upper part of the scanner.

FIG. 3 is an enlarged view showing the structure of the main body 100 of the copying machine. The copying machine main body 100 includes an intermediate transfer belt 1 which is an intermediate transfer member as an endless belt-shaped image carrier.
0 is provided. This intermediate transfer belt 10 is shown in FIG.
As shown in (3), the base layer 11, the elastic layer 12, and the coat layer 13 have a three-layer structure. The base layer 11 is made of, for example, a fluororesin having a low elongation, a rubber material having a high elongation, or a material which is hard to elongate such as canvas. Also, the elastic layer 1
2 is made of, for example, a fluorine-based rubber or an acrylonitrile-butadiene copolymer rubber, and is formed on the base layer 11. The coat layer 13 is formed by coating the surface of the elastic layer 12 with, for example, a fluororesin. The intermediate transfer belt 10 is stretched over the three support rollers 14, 15 and 16 in the state shown in FIG.
It is driven to rotate in the clockwise direction.

Of the supporting rollers, a belt stretched portion between the first supporting roller 14 and the second supporting roller 15 has four image forming units 18Y, 18C, 18M and 18K of yellow, cyan, magenta and black. Are arranged side by side. These image forming units 18Y, 18C,
An exposure device 21 is provided above the 18M and 18K as shown in FIG. The exposure device 21 forms an electrostatic latent image on the photoconductor drums 20Y, 20C, 20M, 20K as latent image carriers provided in each image forming unit, based on the image information of the original read by the scanner 300. It is for doing. A secondary transfer device 22 is provided at a position facing the third support roller 16 among the support rollers. The secondary transfer device 22 has a structure in which an endless belt-shaped secondary transfer belt 24 is stretched between two rollers 23a and 23b. Then, when the toner image on the intermediate transfer belt 10 is secondarily transferred onto the transfer paper, the secondary transfer belt 24 is pressed against the portion of the intermediate transfer belt 10 wound around the third support roller 16 to perform the secondary transfer. I do. The secondary transfer device 22 does not have to have the configuration using the secondary transfer belt 24, but may have a configuration using, for example, a transfer roller or a non-contact transfer charger. Further, a fixing device 25 for fixing the toner image transferred on the transfer paper is provided on the downstream side of the secondary transfer device 22 in the transfer paper conveyance direction by the secondary transfer belt 24. The fixing device 25 has a structure in which a pressure roller 27 is pressed against a heating roller 26. Further, among the supporting rollers of the intermediate transfer belt 10, at a position facing the second supporting roller 15,
A belt cleaning device 17 is provided. The belt cleaning device 17 is for removing the residual toner remaining on the intermediate transfer belt 10 after the toner image on the intermediate transfer belt 10 is transferred onto a transfer sheet as a recording material.

Next, the image forming units 18Y, 18C,
The configuration of 18M and 18K will be described. In the following description, the image forming unit 18K that forms a black toner image
The image forming unit 18 will be described as an example.
Y, 18C, and 18M also have the same structure. FIG. 5 is an enlarged view showing the configuration of two adjacent image forming units 18M and 18K. In the reference numerals in the figure, the symbols "M" and "K" indicating the distinction of colors are omitted, and the symbols are appropriately omitted in the following description. In the image forming unit 18, a charging device 60, a developing device 61, and a photoconductor cleaning device 63 are provided around the photoconductor drum 20. In addition, the intermediate transfer belt 1 is attached to the photosensitive drum 20.
A primary transfer device 62 is provided at a position facing each other through 0.

The charging device 60 is of a contact charging type which employs a charging roller, and contacts the photosensitive drum 20 to apply a voltage to uniformly charge the surface of the photosensitive drum 20. As the charging device 60, a non-contact charging type device such as a non-contact scorotron charger may be used.

The developing device 61 may use a one-component developer, but in this embodiment, a two-component developer composed of a magnetic carrier and a non-magnetic toner is used. The developing device 61 can be roughly divided into a stirring unit 66 and a developing unit 67. In the stirring section 66, the two-component developer (hereinafter, simply referred to as “developer”) is conveyed while being stirred and supplied onto the developing sleeve 65 as a developer carrier. The stirring unit 66 is provided with two parallel screws 68, and a partition plate for partitioning the two screws 68 so that they are communicated with each other at both ends. Further, a toner concentration sensor 71 for detecting the toner concentration of the developer in the developing device is attached to the developing case 70. On the other hand, in the developing section 67, the toner of the developer attached to the developing sleeve 65 is transferred to the photosensitive drum 20. The developing unit 67 has a developing sleeve 65 facing the photoconductor drum 20 through an opening of the developing case 70.
And a magnet (not shown) is fixedly arranged in the developing sleeve 65. Further, a doctor blade 73 is provided so that the tip of the developing sleeve 65 approaches the developing sleeve 65. In this embodiment, the distance between the doctor blade 73 and the developing sleeve 65 at the closest point is set to 500 μm.

In this developing device 61, the developer is conveyed and circulated while being agitated by the two screws 68, and the developing sleeve 6
Supply to 5. The developer supplied to the developing sleeve 65 is drawn and held by a magnet. The developer drawn into the developing sleeve 65 is
Is conveyed with the rotation of and is regulated to an appropriate amount by the doctor blade 73. The regulated developer is returned to the stirring section 66. The developer thus conveyed to the developing area facing the photoconductor drum 20 is in the state of a spike by the magnet to form a magnetic brush. In the developing area, the developing bias applied to the developing sleeve 65 forms a developing electric field that moves the toner in the developer to the electrostatic latent image portion on the photosensitive drum 20. As a result, the toner in the developer is transferred to the electrostatic latent image portion on the photoconductor drum 20, the electrostatic latent image on the photoconductor drum 20 is visualized, and a toner image is formed. The developer that has passed through the developing area is conveyed to a portion where the magnetic force of the magnet is weak, is separated from the developing sleeve 65, and is returned to the stirring section 66.

When the toner concentration in the stirring section 66 becomes low due to the repetition of such operations, the toner concentration sensor 71 detects it, and based on the detection result, the stirring section 66.
Is replenished with toner. The toner scattered at the time of development is sucked into the developing duct 310 described later.

Further, the primary transfer device 62 employs a primary transfer roller and is installed so as to be pressed against the photosensitive drum 20 with the intermediate transfer belt 10 interposed therebetween. The primary transfer device 62 does not have to have a roller shape, but may have a conductive brush shape or a non-contact corona charger. The toner scattered during the primary transfer is sucked into the primary transfer duct 320 described later.

The photoconductor cleaning device 63 is also used.
Is provided with a cleaning blade 75 made of polyurethane rubber, for example, which is arranged so that its tip is pressed against the photosensitive drum 20. In addition, in the present embodiment, a conductive fur brush 76 that contacts the photoconductor drum 20 is also used in order to improve cleaning performance. A bias is applied to the fur brush 76 from a metal electric field roller 77, and the tip of a scraper 78 is pressed against the electric field roller 77. The toner removed from the photoconductor drum 20 by the cleaning blade 75 and the fur brush 76 is stored inside the photoconductor cleaning device 63. Then, the recovery screw 79
Is moved to one side of the photoconductor cleaning device 63 by
Through the toner recycling device 80 described later, the developing device 6
It is returned to 1 and reused.

The static eliminator 64 is composed of a static eliminator lamp and irradiates light to initialize the surface potential of the photosensitive drum 20.

Regarding the specific setting of this embodiment, the diameter of the photosensitive drum 20 is 50 mm, and the photosensitive drum 2
0 is driven at a linear velocity of 200 mm / s. Further, the developing sleeve 65 has a diameter of 18 mm, and
5 is driven at a linear velocity of 240 mm / s. The charge amount of the toner in the developer supplied to the developing area is preferably in the range of about − (minus) 10 to −30 μC / g. In addition, the photosensitive drum 20 and the developing sleeve 6
5, the development gap, which is the gap between them, is 0.8 to 0.4 mm.
It is possible to set in the range of, and it is possible to improve the developing efficiency by reducing the value. The thickness of the photosensitive layer of the photosensitive drum 20 is 30 μm, the beam spot diameter of the optical system of the exposure device 21 is 50 × 60 μm, and the light amount thereof is 0.47 mW. Further, the surface of the photosensitive drum 20 is uniformly charged by the charging device 60 to −700V, and the potential of the electrostatic latent image portion irradiated with the laser by the exposure device 21 becomes −120V. On the other hand, in this embodiment, the voltage of the developing bias is set to -470V and the developing potential of 350V is secured.

In the image forming unit 18 having the above-described structure, the charging device 6 is rotated with the rotation of the photosensitive drum 20.
At 0, the surface of the photoconductor drum 20 is uniformly charged. Then, based on the image information read by the scanner 300, the exposure device 21 irradiates the writing light L from a laser, an LED or the like to form an electrostatic latent image on the photosensitive drum 20. Then, the developing device 61 visualizes the electrostatic latent image to form a toner image. This toner image is transferred to the primary transfer device 62.
Is primarily transferred onto the intermediate transfer belt 10. The transfer residual toner remaining on the surface of the photoconductor drum 20 after the primary transfer is removed by the photoconductor cleaning device 63, and then the surface of the photoconductor drum 20 is destaticized by the destaticizing device 64 to form the next image. Be served.

Next, the structure and operation of the toner recycling device 80 for reusing the transfer residual toner collected by the photoconductor cleaning device 63 in the developing device 61 will be described. FIG. 6 is an explanatory diagram showing a schematic configuration of the toner recycling device 80. FIG. 7 is an enlarged view of one end portion of the recovery screw 79 of the photoconductor cleaning device 63.
As shown in FIG. 7, the toner recycling device 80 includes a roller portion 82 provided at one end of the recovery screw 79 of the photoconductor cleaning device 63. This roller portion 82
A pin 81 is provided on the. This roller portion 82 is
A belt-shaped collected toner conveying member 83 is stretched around the roller portion 87 of the rotating shaft 86. At this time, the roller portion 8
The second pin 81 enters into the long hole 84 provided in the collected toner conveying member 83. Blades 85 are provided at regular intervals on the outer peripheral surface of the collected toner conveying member 83.

As shown in FIG. 6, the collected toner carrying member 83 is housed in the carrying path case 88 together with the rotary shaft 86. The transport path case 88 is integrally molded with a cartridge case 89 that integrally houses at least a part of the components of the image forming unit 18. Inside the transport path case 88, one of the two screws 68 is
The book projects from the inside of the developing device 61.

In such a structure, a driving force is transmitted from the outside to rotate the recovery screw 79 and rotationally drive the recovered toner conveying member 83. As a result, the toner collected by the photoconductor cleaning device 63 is conveyed toward the developing device 61 through the conveyance path case 88,
It is housed inside the developing device 61 by the screw 68.
After that, the collected toner is circulated by being agitated together with the developer in the developing device 61 by the two screws 68 as described above, and contributes to the development again.

Next, the operation of the copying machine in this embodiment will be described. When making a copy of a document using the copying machine having the above-described configuration, first, the document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened and the contact glass 3 of the scanner 300 is opened.
The original is set on the sheet 2, and the automatic document feeder 400 is closed and pressed by it. After that, when the user presses a start switch (not shown), when the document is set on the automatic document feeder 400, the document is conveyed onto the contact glass 32. Then, the scanner 300 is driven and the first
The traveling body 33 and the second traveling body 34 start traveling. As a result, the light from the first traveling body 33 is reflected by the document on the contact glass 32, the reflected light is reflected by the mirror of the second traveling body 34, and is guided to the reading sensor 36 through the imaging lens 35. . In this way, the image information of the original is read.

When the start switch is pressed by the user, a drive motor (not shown) is driven, and one of the support rollers 14, 15, 16 is rotationally driven, and the intermediate transfer belt 10 is rotationally driven. At the same time, the photosensitive drums 20Y, 20C, 20M and 20K of the image forming units 18Y, 18C, 18M and 18K are also rotationally driven. Thereafter, based on the image information read by the reading sensor 36 of the scanner 300, the writing light L is applied from the exposure device 21 onto the photoconductor drums 20Y, 20C, 20M and 20K of the image forming units 18Y, 18C, 18M and 18K. Are irradiated respectively. As a result, each photoconductor drum 20
An electrostatic latent image is formed on each of Y, 20C, 20M, and 20K, and visualized by developing devices 61Y, 61C, 61M, and 61K. Then, each photosensitive drum 20Y,
On 20C, 20M, and 20K, yellow,
Cyan, magenta, and black toner images are formed.
The toner images of the respective colors formed in this manner are primary-transferred by the primary transfer devices 62Y, 62C, 62M, and 62K so as to sequentially overlap with each other on the intermediate transfer belt 10. As a result, a synthetic toner image in which the toner images of the respective colors are superposed is formed on the intermediate transfer belt 10. The transfer residual toner remaining on the intermediate transfer belt 10 after the secondary transfer is removed by the belt cleaning device 17.

When the user presses the start switch, the paper feed roller 42 of the paper feed table 200 corresponding to the transfer paper selected by the user is rotated, and the transfer paper is sent out from one of the paper feed cassettes 44. The transferred transfer paper is separated into one sheet by a separation roller 45, enters a paper feed path 46, and is conveyed by a conveyance roller 47 to a paper feed path 48 in the copying machine main body 100. The transfer sheet conveyed in this manner is stopped when it hits the registration roller 49. When using the transfer paper not set in the paper feed cassette 44, the transfer paper set in the manual feed tray 51 is sent out by the paper feed roller 50, separated by the separation roller 52 into one sheet, and then the manual paper feed path. It is transported through 53. Then, similarly, when it hits the registration roller 49, it is stopped.

The registration roller 49 transfers the synthetic toner image formed on the intermediate transfer belt 10 as described above.
The rotation is started at the timing of being conveyed to the secondary transfer portion of the secondary transfer device 22 facing the secondary transfer belt 24. Here, the registration roller 49 is generally grounded and used in many cases, but a bias may be applied to remove the paper dust of the transfer paper. The transfer paper sent by the registration roller 49 is the intermediate transfer belt 1
0 is fed between the secondary transfer belt 24 and the secondary transfer belt 24, and the secondary transfer device 22 secondarily transfers the synthetic toner image on the intermediate transfer belt 10 onto the transfer paper. After that, the transfer paper is conveyed to the fixing device 25 in a state of being attracted to the secondary transfer belt 24, and the fixing device 25 applies heat and pressure to fix the toner image. The transfer sheets that have passed through the fixing device 25 are discharged onto a discharge tray 57 by a discharge roller 56 and stacked. When the image is formed on the back side of the surface on which the toner image is fixed, the transfer claw 55 switches the transfer path of the transfer sheet that has passed through the fixing device 25. Then, the transfer sheet is sent to the sheet reversing device 28 located below the secondary transfer device 22, is reversed there, and is guided to the secondary transfer portion again.

Next, the structure and operation of the dust amount detection system for detecting the amount of scattered toner as dust, which is a characteristic part of the present invention, will be described. As described above, inside the copying machine, specifically, inside the copying machine main body 100, dust is generated at various places such as toner scattering in the developing area and toner scattering in the primary transfer portion and the secondary transfer portion. In particular, toner scattering is likely to occur in the developing area, but more specifically, it is more likely to occur in the area downstream of the developing area in the developing sleeve surface movement direction. In addition, toner scattering also occurs in the primary transfer portion that primarily transfers the toner image on the photosensitive drum 1 to the intermediate transfer belt 10, more specifically, in the downstream side region of the intermediate transfer belt 10 in the surface movement direction of the primary transfer portion. It is easy to occur. Also,
Toner scattering is likely to occur even in a curved portion of the intermediate transfer belt 10 which is largely curved, specifically, a portion wound around the first support roller 14 and the second support roller 15.

Therefore, inside the main body 100 of the copying machine according to the present embodiment, there are provided ducts each having an opening at an area where toner is likely to be scattered. Specifically, as shown in FIG. 5, a developing duct 310 is provided as a dust passage forming unit having an inlet opening at a downstream side region in the developing sleeve surface moving direction with respect to the developing region. Further, as shown in FIG. 5, there is also provided a primary transfer duct 320 as a dust passage forming means having an inlet opening in a downstream side area in the surface moving direction of the intermediate transfer belt 10 with respect to the primary transfer portion. Further, as shown in FIG. 3, there is also provided a belt curved portion duct 330 as a dust passage forming means having an inlet opening at a portion wound around the first support roller 14. As shown in FIG. 3, a fixing duct 340 is also provided as a dust passage forming unit having an inlet opening across the fixing device 25 in a portion wound around the second supporting roller 15.

FIG. 1 is a schematic block diagram showing an example of a dust amount detection system for detecting the total amount of scattered toner generated inside the machine. This dust amount detection system includes one suction duct 350 as a dust passage forming means. The inlet of the suction duct 350 is, as shown in the drawing, the developing duct 3
10, primary transfer duct 320, belt bend duct 330
And all of the fixing duct 340. The entrances of the developing duct 310 and the primary transfer duct 320 are formed in each of the image forming units 18Y, 18C, 18M and 18K. Then, each image forming unit 18
Development duct 31 corresponding to Y, 18C, 18M, 18K
The 0 and primary transfer ducts 320 are configured to join together on the way and then communicate with the suction duct 350.

Each duct 310, 320, 330, 340
Each of the inlets has a suitable shape so that all the scattered toner generated at the corresponding locations can be collected. Specifically, for example, the developing duct 310 has a shape in which the inlet 311 is opened over the entire axial direction of the developing sleeve 65, as shown in FIG. Although not shown, the inlet 321 of the primary transfer duct 320 is also opened over the entire area of the photosensitive drum 20 in the axial direction, like the inlet of the developing duct 310. In addition, similarly, the inlet 33 of the belt curved portion duct 330 and the fixing duct 340
1, 341 are open over the entire width direction orthogonal to the surface movement direction of the intermediate transfer belt 10.

The outlet of the suction duct 350 communicates with the exhaust duct 360, and the exhaust duct 360 is provided with a suction fan 351 as an air flow generating means. When the suction fan 351 is driven, the suction duct 3
An airflow is generated in a direction from 50 to the exhaust duct 360 (hereinafter, referred to as “suction direction”). As a result, dust such as scattered toner generated in the developing area, the transfer portion, or the like, will enter the inlets 311 and 3 of the ducts 310, 320, 330 and 340.
It is sucked from 21, 331 and 341 and collected. In addition, a pre-filter 354 for collecting relatively large dust such as lint and coarse powder is provided in the suction duct 350 after the ducts 310, 320, 330 and 340 have joined. Further, on the downstream side of the pre-filter 354 in the suction direction and on the upstream side of the suction fan 351 in the suction direction,
Specifically, at the boundary between the suction duct 350 and the exhaust duct 360, a dust collecting filter 352 as a dust collecting means and an ozone decomposing filter 353 are provided. Dust collection filter 35
2 is for collecting dust such as scattered toner, and the ozone decomposing filter 353 is for performing ozone decomposing processing.

In this embodiment, each duct 310,
320, 330, 340 are these inlets 311 and 32
Although the scattered toner sucked from 1,331,341 is drawn into the rear side of the main body, the shape is not limited to this. Further, in the present embodiment, a method of sucking from the outlet side of the suction duct 350 by the suction fan 351 is adopted, but a method of blowing with a fan or the like from the inlet side of the suction duct 350 may be adopted. Further, if these methods are used together, the scattered toner can be collected more efficiently.

The scattered toner sucked into the ducts 310, 320, 330 and 340 by the air flow generated by the suction fan 351 enters the suction duct 350 from each duct and reaches the pre-filter 354. This allows
Although the lint, coarse powder, and the like are collected by the pre-filter 354, dust such as scattered toner having a small particle diameter passes through the pre-filter 354 without being collected. Suction duct 3
The scattered toner passing through the inside of 50 is collected by the dust collecting filter 352. Then, the gas that has passed through the dust collecting filter 352 is subjected to ozone decomposition processing by the ozone decomposition filter 353, and then discharged through the exhaust duct 360 to the outside of the machine. The pre-filter 354 is not always necessary, but if dust with a large particle size is removed at this position, clogging of the dust collecting filter 352 and erroneous detection of the dust amount detection sensor described later can be effectively suppressed. be able to.

FIG. 9 is a partially enlarged view of the suction duct 350. In the present embodiment, the portion of the suction duct 350 between the pre-filter 354 and the dust collecting filter 352 is branched into the main flow duct 355 and the branch duct 356. The mainstream duct 355 extends substantially straight from the pre-filter 354 toward the dust collecting filter 352. On the other hand, the branch duct 356 is separated from the mainstream duct 355 to form another dust passage. A dust amount detection sensor 37 as dust amount detection means is provided in the middle of the branch duct 356.
0 is placed. This dust amount detection sensor 370 is
This is for detecting the amount of scattered toner passing through the inside of the branch duct 356.

FIG. 10 is a schematic diagram showing the dust amount detection sensor 370. The dust amount detection sensor 370 has
An optical sensor that is widely used as a dust sensor is generally used, but the dust sensor is not limited to this. The basic configuration of the dust amount detection sensor 370 in this embodiment is LE
A light emitting element 371 including a D (light emitting diode), and PT
and a light receiving element 372 formed of r (phototransistor). The light from the light emitting element 371 is condensed by the lens 373 and then radiated into the inside of the branch duct 356. Then, the radiated light causes the branch duct 356.
When reflected by the scattered toner passing through the inside, the reflected light is condensed through the lens 374 and then received by the light receiving element 372.

The light emitting element 371 and the light receiving element 372 may be arranged anywhere as long as the light receiving element 372 can receive the reflected light from the scattered toner passing through the branch duct 356. However, the light emitting element 371 and the light receiving element 372 are connected to the branch duct 35.
If it is arranged vertically below 6, the suction fan 351
After the driving is stopped, the scattered toner in the branch duct 356 is naturally dropped and the light emitting element 371 and the light receiving element 372 are contaminated. If the light emitting element 371 and the light receiving element 372 are contaminated, an error will occur in the detection result by the dust amount detection sensor 370. Therefore, the light emitting element 371 and the light receiving element 3
It is desirable that 72 is arranged vertically above the branch duct 356 as in the present embodiment, or is arranged in a horizontal position with respect to the branch duct 356.

FIG. 11 is a block diagram showing the circuit arrangement of the dust amount detection sensor 370. When the image forming operation is started, the control unit of the copying machine (not shown) drives the suction fan 351 and outputs a drive command to the dust amount detection sensor 370. As a result, the dust amount detection sensor 37
The 0 LED drive circuit 375 starts driving, and the light emitting element 3
71 emits light. When the light is reflected by the scattered toner passing through the inside of the branch duct 356 and the reflected light is received by the light receiving element 372, a voltage according to the amount of light received from the light receiving element 372 is output. The voltage is amplified by the amplifier circuit 376, post-processed by the post-processing circuit 377, and output to the control unit of the copying machine. This detection operation is performed until the transfer paper passes from the fixing device 25. In the present embodiment, the output characteristic of the dust amount detection sensor 370 with respect to the concentration (dust concentration) of the scattered toner passing through the branch duct 356 is as shown in FIG.

In the present embodiment, the suction duct 350 is branched to detect the amount of scattered toner passing through the branch duct 356, but it is also possible to detect the amount without branching. However, in the present embodiment, a commercially available inexpensive sensor is used as the dust amount detection sensor 370 in order to suppress the cost and realize the toner scattering amount detection. Since this commercially available sensor uses an LED with a small amount of light emission as the light emitting element 371, its detection range is narrow.
On the other hand, in order to obtain a sufficient recovery capacity in the developing duct 310, the primary transfer duct 320, etc., a duct diameter that is somewhat large is required. Moreover, the dust passing through the duct is
The flow may be disturbed due to bending of the duct. This turbulence is large near the inner wall of the duct, but small near the center of the duct cross section, so the behavior of dust passing near the center is relatively stable. Therefore, it is desirable to detect the amount of dust passing near the center of the duct cross section for proper detection. For the above reasons, the suction duct 35
In order to perform appropriate detection without branching 0, it becomes necessary to arrange the entire dust amount detection sensor 370 inside the duct. In this case, the light emitting element 371 and the light receiving element 372 are easily contaminated, and it becomes difficult to realize stable detection. On the contrary, the light emitting element 371 and the light receiving element 372 are connected to the suction duct 35.
If it is to be placed outside 0, the duct diameter must be reduced in order to detect the amount of dust passing near the center of the duct cross section. In this case, the developing duct 310 or the like cannot obtain a sufficient recovery capacity. Therefore, in the present embodiment, the suction duct 350 is branched so that a duct diameter suitable for the dust amount detection sensor 370 (in the present embodiment, 1
A branch duct 356 having a width of 0 mm). As a result, in this embodiment, a sufficient collection capacity can be obtained in the developing duct 310 and the like by the airflow from the mainstream duct 355, and even if the light emitting element 371 and the light receiving element 372 are arranged outside the duct, the vicinity of the center of the duct The amount of dust passing through can be detected.

Next, the dust handling process performed based on the detection result of the dust amount detection sensor 370 will be described. FIG. 13 is a block diagram showing a schematic configuration of a dust handling system for performing dust handling. The output of the dust amount detection sensor 370 is sent to a central processing unit 601 as a determination means provided in the control unit 600 of the copying machine via a communication interface (hereinafter, referred to as “communication I / F”) 604. In the central processing unit 601, the dust amount detection sensor 3 is used for each image forming operation on one transfer sheet.
70 output histories are recorded. And the central processing unit 6
01 operates as shown in Table 1 below based on the history information.

[Table 1]

The central processing unit 601 has
From the recorded history information, the average value of the density of the scattered toner passing through the branch duct 356 is calculated based on the history of the immediately preceding 100 sheets. This average value is 1.0 mg / m3
In the case of the above, the central processing unit 601 determines that the state of the copying machine is the SC level 1. In the case of SC level 1, the central processing unit 601 has an external interface (hereinafter referred to as “external I / F”) 60 as a notification means.
3 sends SC level information indicating that the status of the copying machine is SC level 1 to the management device 700 of the service center. At this time, nothing is displayed on the display device 602 as an informing unit provided in the operation unit of the copying machine. The SC level information output from the external I / F 603 of the copying machine is transmitted to the service center via a wired communication means such as a public telephone line or a dedicated line or a wireless communication means. At the service center, the SC level information is transferred to an external interface (hereinafter referred to as “external I / F”) 703.
It is received by the central processing unit 701 of the management apparatus 700 via the.

When the average value is 2.0 mg / m 3 or more, the central processing unit 601 determines that the state of the copying machine is SC level 2. In the case of SC level 2, the central processing unit 601 transmits SC level information indicating that the state of the copying machine is SC level 2 to the management apparatus 700 of the service center, as in the case of SC level 1. Further, the central processing unit 601 displays the display device 60 when the copying machine is to be maintained by the user himself.
A notification for instructing maintenance to the user is displayed on 2. On the other hand, when the copier is to be maintained by the operator of the service center, the status of the copier is SC level 2 on the display device 602.
And a notification for informing the user to the service center.

The S transmitted from the copying machine as described above
When the C level information is received by the management device 700 of the service center, the SC level information is notified to the operator from the display device 702. As a result, the operator
The amount of dust generated inside the copying machine, which is the transmission source of the C level information, can be accurately grasped. Therefore, the operator can quickly perform necessary maintenance processing by going to the installation location of the copying machine or instructing the copying machine from the management device 700.

Further, the central processing unit 601 passes through the branch duct 356 based on the output history of the dust amount detection sensor 370 after the copying machine is delivered and first operated or after the dust collecting filter 352 is replaced. The cumulative value of the amount of scattered toner is calculated. When this cumulative value reaches 2 g, the central processing unit 601 determines that the state of this copying machine is SC level 3. In the case of SC level 3, the central processing unit 60
1 is the same as the SC level 1 when the state of the copying machine is S
SC level information indicating that it is C level 3 is transmitted to the management device 700 of the service center. Further, the central processing unit 60
In No. 1, when the copying machine is to be maintained by the user himself, the display device 602 displays a notification for instructing the user to replace the dust collecting filter 352. On the other hand, when the copier is to be maintained by the operator of the service center, the display device 602 is informed of the fact that the copier is in the SC level 3 and notifies the user to the service center. Display it.

Conventionally, the time for exchanging the dust collecting filter 352 is determined according to the number of copies of the copying machine. In this case, if the amount of dust such as scattered toner generated in the machine is larger than the planned amount, the dust collecting filter 352 may be clogged before the scheduled replacement time. When such clogging occurs, as described above, dust such as scattered toner floats inside the machine to cause various problems, and the temperature inside the machine abnormally rises to solidify the developer and drive the developing device 61. It may become impossible. On the contrary,
In the present embodiment, the amount of dust such as scattered toner collected by the dust collecting filter 352 is directly detected, and the replacement time of the dust collecting filter 352 is determined based on the detection result. Therefore, the dust collecting filter 352 can be replaced more appropriately than before.

In this embodiment, the detection result of the dust amount detection sensor 370 is sent to the display unit 602 for notifying the user and the external unit I for sending from the control unit 600 of the copying machine to the management unit 700 of the service center. / F603 is provided. However, the configuration may be such that only one of them is provided.

[Modification] Next, a modification of the dust amount detection system and the dust handling system according to the present embodiment will be described. FIG. 14: is a schematic block diagram which shows the dust amount detection system in this modification. This dust amount detection system is similar to the above-described embodiment in that the developing duct 3
10, primary transfer duct 320, belt bend duct 330
The fixing duct 340 collects the scattered toner and exhausts it through the suction duct 350. However, the present modified example and the above-described embodiment include the dust amount detection sensor 37.
The location of 0 is different.

More specifically, in the dust amount detection system of the present modification, the developing duct 310 and the primary transfer duct 320 corresponding to each of the image forming units 18Y, 18C, 18M and 18K are provided as in the above embodiment. They join each other. And each communication duct 3 immediately after the merge
80Y, 380C, 380M, 380K, dust amount detection sensors 370Y, 370C, 370M, 370 respectively
K is arranged. This communication duct 380Y, 380
C, 380M, and 380K are mainstream ducts 381Y, 381C, and 38, like the suction duct 350 of the above embodiment.
1M, 381K and branch ducts 382Y, 382C, 38
It branches into 2M and 382K. Then, the respective dust amount detection sensors 370Y, 370C, 370M, 370K are arranged in the branch ducts 382Y, 382C, 382M, 382K, respectively.

When the dust handling process similar to that of the above embodiment is performed using the configuration of this modification, the central processing unit 60 is used.
1 is operated, for example, as shown in Table 2 below.

[Table 2]

Further, according to the configuration of this modification, the amount of scattered toner generated for each of the image forming units 18Y, 18C, 18M and 18K can be detected. In this way, by detecting the amount of scattered toner for each of the image forming units 18Y, 18C, 18M, and 18K, it is possible to specifically specify the location where a large amount of scattered toner is generated. Therefore, it becomes possible to perform appropriate maintenance processing by the user or operator of the service center more quickly and appropriately. Specifically, for example, the detection results of the dust amount detection sensors 370Y, 370C, 370M, 370K are the same as those in the above-described embodiment, and the management device 7 of the service center.
Sent to 00. Therefore, the operator can appropriately carry the replacement parts, tools, and the like that are required when going to the installation place of the copying machine. Therefore, it is possible to prevent a situation in which there is no replacement part or tool necessary for maintenance at the installation place of the copying machine and a re-visit is required.

In this modification, the connecting ducts 38 are formed after the developing duct 310 and the primary transfer duct 320 have joined.
Dust amount detection sensors 370Y, 370C, 370M, and 370K are arranged at 0Y, 380C, 380M, and 380K, respectively. On the other hand, the dust amount detection sensor 370 may be provided instead of this arrangement location or in addition to this configuration. For example, the dust amount detection sensor 370 may be added to the suction duct 350 as in the above embodiment. Further, the dust amount detection sensors 370Y, 370C,
In place of or in addition to 370M and 370K, the dust amount detection sensor 3 is attached to the belt curved portion duct 330 and the fixing duct 340.
70 may be provided. Further, when it is desired to more specifically specify the location where toner scattering occurs than in the configuration of the present modification, a dust amount detection sensor is provided in each of the ducts 310 and 320 before the developing duct 310 and the primary transfer duct 320 merge. 370 may be arranged.

As described above, according to this embodiment, the latent image on the photosensitive drum 20 as the latent image carrier is developed with the developer, and the formed toner image is recorded on the transfer paper as the recording material to form an image. A copying machine as an image forming apparatus for forming a toner is provided with a dust collecting filter 352 as dust collecting means for collecting scattered toner that is dust generated inside the machine, and an air flow for conveying the scattered toner to the dust collecting filter 352. Inside of the suction fan 351 as an air flow generation means to be generated, and the development duct 310, the primary transfer duct 320, the belt bending duct 330, the fixing duct 340, and the suction duct 350, which are dust paths through which dust is conveyed by the air flow. Since it has a dust amount detection sensor 370 as a dust amount detecting means for detecting the amount of the scattered toner, it is more suitable than the scattered toner in the floating state. Distributed to, and dust amount detecting sensor 370 with respect to the scattered toner in a state flowing in a predetermined direction
Can be detected. Therefore, the dust density existing in the detection range of the dust amount detection sensor 370 is lower than that of the image forming apparatus of the above-mentioned Japanese Patent No. 3140329, and since the scattered toner is on the air stream, the scattered toner is detected by the dust amount detection sensor 370. Difficult to adhere to. Moreover, since the behavior of the dust existing in the detection range is more stable than that of the dust in the floating state, the dust amount detection sensor 370 can detect the dust exhibiting such stable behavior. As described above, according to the copying machine of the present embodiment, it is possible to realize stable detection of the amount of dust floating in the machine, and it is possible to accurately prevent various problems caused by the increase in dust. Also, the above-mentioned Japanese Patent No. 31403
In the image forming apparatus disclosed in Japanese Patent No. 29, an optical sensor, which is a dust amount detecting means, is arranged immediately below the developing device 61 in which toner scattering easily occurs. However, the amount of toner scattered just below the developing device is not always uniform in the axial direction of the photosensitive drum. Therefore, even if the optical sensor which is the toner scattering detection means is arranged only in a part of the axial direction, the total toner scattering amount generated in the developing device cannot be properly detected from the detection result. Further, the scattered toner generated from the developing device is not always generated just below the developing device. Therefore, even if the optical sensor is arranged just below the developing device, the scattered toner is not detected except under the developing device. . Therefore, in order to detect the total amount of toner scattering generated in the developing device, a large number of optical sensors must be arranged, which results in a high cost. On the other hand, in the copying machine according to the present embodiment, it is possible to collect the dust around the developing device by the air flow, and it is possible to detect the amount of dust after the collection, so that the above-mentioned Japanese Patent No. 3140329. It is possible to detect the total amount of dust existing around the developing device by using the dust amount detection sensors 370 that are smaller in number than the image forming apparatus disclosed in the publication. Therefore, it is possible to realize appropriate detection at low cost. Not only the developing device but also the entire amount of dust existing around other places where dust can be generated can be detected by the small number of dust amount detection sensors 370 in the same manner. Further, similarly, it is also possible to collect and detect dust generated at a plurality of locations by an air flow, and it is possible to realize appropriate detection of the amount of dust generated in a wide range inside the machine at low cost. Become. Further, in the copying machine according to the present embodiment, since the dust detection sensor 370 detects the suction duct 350,
The space in which the dust amount detection sensor 370 is installed can be made wider than directly below the developing device 61. Therefore, the degree of freedom of the installation space of the dust amount detection sensor 370 is higher than that of the image forming apparatus of Japanese Patent No. 3140329,
There is almost no restriction on the dust amount detection means that can be used, and the cost can be suppressed. Further, in the present embodiment, the developing ducts 310, 1 as dust passage forming means for forming a dust passage whose inside is a part of the dust passage.
Since the dust transfer amount detection sensor 370 has the next transfer duct 320, the belt curved portion duct 330, the fixing duct 340, and the suction duct 350, and detects the dust amount in the dust passage,
Dust existing in the detection range exhibits more stable behavior, and more stable detection of the amount of dust floating in the machine can be realized. Further, in the copying machine of the present embodiment, the amount of dust is not directly detected at a place where dust such as scattered toner may be generated, but the amount of dust conveyed from that place through the dust passage is detected. With such a configuration, even if dust is generated at a plurality of locations inside the machine, the dust can be collected by the airflow generating means simply by disposing the inlet of the dust passage at each location. Therefore, the above-mentioned Japanese Patent No. 3140329
It is possible to detect the total amount of dust generated at a plurality of locations by using the dust amount detection sensors 370 that are smaller in number than the image forming apparatus of the publication. Therefore, appropriate detection of the total amount of dust generated at a plurality of locations can be realized at low cost. Further, in the present embodiment, the suction duct 35
0 forms at least two branched dust passages on the downstream side, and the dust amount detection sensor 370 detects the amount of scattered toner by the branch duct 356 which is a part of the branched passage portion of the dust passage. As described above, the developing duct 310
It is possible to obtain the branch duct 356 according to the detection range of the light emitting element 371 and the light receiving element 372 while ensuring the recovery capability in the airflow from the mainstream duct 355. Therefore, even if an inexpensive dust amount detection sensor 370 having a narrow detection range is used, the amount of dust having stable behavior passing near the center of the cross section of the branch duct 356 is detected with the sensor placed outside the duct. be able to. Further, in the above modification, each duct 310, 320, 330, 340.
Forms a plurality of dust passages in which the inlets 311, 321, 331, 341 of each duct open at different positions in the machine, and the dust amount detection sensor 370 scatters in at least one of the plurality of dust passages. Since the amount of toner is detected, the image forming units 18Y, 18C, 18M, 18K
Developing duct 310 and primary transfer duct 320 corresponding to
Connecting ducts 380Y, 380C, 380
If the dust amount detection sensor 370 is provided for each of the M and 380K, it is possible to specifically specify a location in the machine where toner scattering occurs. Therefore, it is possible to take more appropriate measures against toner scattering. In addition, in the above-described modified example, the ducts 310 and 320 have the inlet 31
A communication duct 380Y, which is a dust passage in which 1,321,331,341 open at different positions in the aircraft, and the passages extending from the respective inlets 311 and 321 merge.
380C, 380M, 380K are formed, and the dust amount detection sensors 370Y, 370C, 370M, 370K detect the amount of scattered toner by the communication ducts 380Y, 380C, 380M, 380K, and therefore, the scattering amount sucked from the respective inlets 311 and 321. The total amount of toner can be detected. Therefore, the number of dust amount detection sensors can be suppressed to a small number, and the cost can be reduced. In particular, the above-described modification includes a plurality of developing devices 61Y, 61C, 61M, 61K for developing a plurality of latent images with developers of different colors,
The ducts 310 and 320 are connected to the developing devices 61Y and 61Y, respectively.
Dust passages are formed for C, 61M, and 61K, and the inlets 311 and 321 of the dust passages are opened in the machine because the dust passages are opened at different positions near the corresponding developing device. Toner can be detected for each color. Therefore, it is possible to specifically identify the location in the machine where the toner is scattered, for each color,
It becomes possible to take more appropriate measures against toner scattering. In particular, since this modification is a tandem type color copying machine, there are four types of yellow, cyan, magenta, and black.
Image forming units 18Y, 18C, 18M, 18K
Exists. Therefore, the number of places where toner scattering occurs is about four times that of a monochrome copying machine or a color copying machine using a single photosensitive drum. In this case, even if the number of dust amount detection sensors is smaller than that of the conventional device in which a dust amount detection sensor is individually provided at the place where toner scattering occurs, the location inside the machine where toner scattering occurs is specified specifically for each color. It becomes possible to do. Further, in the present embodiment, the central processing unit 601 as a judgment means for judging whether or not the amount of scattered toner passing through the dust passage exceeds a predetermined amount based on the detection result of the dust amount detection sensor 370, A display device 602 as an informing unit and an external device I for informing when the central processing unit 601 determines that the predetermined amount is exceeded.
Since / F603 is provided, it is possible to notify the user, the operator of the service center, etc. of the state of the copying machine regarding the amount of scattered toner. As a result, it is possible to quickly take measures to prevent the state of the copying machine from deteriorating. Therefore, convenience for both the user and the service company is improved.

[0056]

According to the invention of claims 1 to 6, since dust is unlikely to adhere to the dust amount detecting means, and the behavior of the dust to be detected by the dust amount detecting means is stable,
There is an excellent effect that it is possible to realize stable detection of the amount of dust floating in the machine, and it is possible to accurately prevent various problems caused by the increase in dust.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a dust amount detection system that detects a total amount of scattered toner generated inside a copying machine according to an embodiment.

FIG. 2 is a schematic configuration diagram of the entire copying machine.

FIG. 3 is an enlarged view showing a configuration of a main body portion of the copying machine.

FIG. 4 is a sectional view showing a structure of an intermediate transfer belt provided in the copying machine.

FIG. 5 is an enlarged view showing a configuration of two image forming units provided in the copying machine.

FIG. 6 is an explanatory diagram showing a schematic configuration of a toner recycling device provided in the copying machine.

FIG. 7 is an enlarged view of one end portion of a recovery screw of the photoconductor cleaning device provided in the copying machine.

FIG. 8 is an explanatory diagram showing an inlet shape of a developing duct provided in the copying machine.

FIG. 9 is a partially enlarged view of a suction duct provided in the copying machine.

FIG. 10 is a schematic configuration diagram showing a dust amount detection sensor provided in the copying machine.

FIG. 11 is a block diagram showing a circuit configuration of the same dust amount detection sensor.

FIG. 12 is a graph showing output characteristics of the dust amount detection sensor.

FIG. 13 is a block diagram showing a schematic configuration of a dust handling processing system in the copying machine.

FIG. 14 is a schematic configuration diagram showing a dust amount detection system in a modified example.

[Explanation of symbols]

10 Intermediate transfer belt 18 Image forming unit 20 photoconductor drum 24 Secondary transfer belt 25 Fixing device 61 Developing device 65 Development sleeve 100 Copier body 200 paper feed table 300 scanner 310 Development duct 320 Primary transfer duct 330 Belt bend duct 340 fixing duct 350 suction duct 351 suction fan 352 Dust collection filter 355,381 Mainstream duct 356, 382 Branch duct 370 Dust amount detection sensor 371 light emitting device 372 light receiving element 380 each communication duct 400 Automatic document feeder 600 control unit 601, 701 Central processing unit 602, 702 display device 603,703 External I / F 700 management device

Claims (6)

[Claims] 1. An image forming apparatus for developing a latent image on a latent image carrier with a developer and recording the formed toner image on a recording material to form an image. Dust collecting means, an air flow generating means for generating an air flow for conveying the dust to the dust collecting means, and a dust amount detection for detecting the amount of dust in the dust path where the dust is conveyed by the air flow. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, further comprising: a dust passage forming means for forming a dust passage which is a part of the dust passage, wherein the dust amount detecting means comprises a dust passage in the dust passage. An image forming apparatus characterized by detecting the. 3. The image forming apparatus according to claim 2, wherein the dust passage forming means forms a dust passage branched into at least two on the downstream side, and the dust amount detecting means forms a passage divided from the dust passage. An image forming apparatus characterized by detecting the amount of dust in a part of the portion. 4. The image forming apparatus according to claim 2, wherein the dust passage forming means forms a plurality of dust passages having inlets of the dust passage opening at different positions in the machine, and the dust amount detecting means. An image forming apparatus, wherein the amount of dust is detected in at least one of the plurality of dust passages. 5. The image forming apparatus according to claim 2, wherein the dust passage forming means includes dust passages in which inlets of the dust passages are opened at different positions in the machine, and passages extending from the inlets are joined. The image forming apparatus is characterized in that the dust amount detecting means detects the amount of dust in the passage portion where the dust passage merges. 6. The image forming apparatus according to claim 1, 2, 3, 4, or 5, whether or not the amount of dust in the dust path exceeds a predetermined amount based on the detection result of the dust amount detecting means. An image forming apparatus, comprising: a determination unit that determines whether or not a predetermined amount has been exceeded, and an informing unit that issues a notification when the determination unit determines that the predetermined amount has been exceeded.