JP2015172725A - Cleaning device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device that selectively switches and conveys an untransferred toner recovered from the surface of the image carrier with the cleaning device to between a disposal side and a recycle side, and can reduce the power consumption without causing an increase in the size, complexity, and cost.SOLUTION: A cleaning device includes a conveyance direction switching part 8 that switches a direction of conveyance of a recovery toner, first recovery toner conveyance means 82a for conveying the recovery toner to a developing device, and second recovery toner conveyance means 83a for conveying the recovery toner to recovery toner storage means. The conveyance direction switching part includes a switching member 81 that switches to either one of a first toner conveyance path 82 that conveys the recovery toner to the developing device or a second recovery toner conveyance path 83 that conveys the recovery toner to the recovery toner storage means, and a conveyance direction switching mechanism 80 that switches a driving force transmission destination to either one of the first recovery toner conveyance means or the second recovery toner conveyance means. The driving force transmission destination can be switched with the conveyance direction switching mechanism simultaneously with the switching of the recovery toner conveyance path with the switching member.

Description

  The present invention relates to a cleaning device having a function of discarding toner removed from an image carrier, a function of returning to a developing unit without recycling, and an image forming apparatus using the cleaning device.

  Conventionally, in an electrophotographic image forming apparatus such as a copying machine, a printer, or a facsimile, the surface of a photoconductor serving as an image carrier is charged by being charged and the original reflected light or laser is applied to the charging unit. An electrostatic latent image is formed by irradiating and exposing optical image information such as a beam. Next, a toner image is formed on the photosensitive member by adhering toner supplied from the developing device to the electrostatic latent image. Next, after the toner image is transferred to a recording medium by a transfer device, the toner image is fixed by heating and pressurizing by a fixing device and discharged outside the apparatus. Since foreign matter such as untransferred toner remains on the surface of the photoreceptor after the toner is transferred to the recording medium, the foreign matter is removed by a cleaning device or the like to prepare for the next image forming process.

The cleaning device collects untransferred toner (about 5% to 20% of the amount of toner adhered at the developing unit) remaining after transfer from the toner image formed on the photoconductor. As a means for cleaning, a blade cleaning method is generally used in which an untransferred toner is removed by bringing an edge portion of a cleaning blade formed of an elastic body such as rubber into contact with a surface to be cleaned of a photoreceptor.
The untransferred toner removed by the cleaning blade is conveyed and discharged to the outside of the cleaning device using a recovery screw provided in the cleaning device.
The recovered toner discharged out of the cleaning device is transported through a recovery path and sent as waste toner to a waste toner recovery bottle or the like or returned to the developing device again as recycled toner to reduce toner consumption. And reused. A system is also known in which the transport destination of the collected toner discharged from the cleaning device is switched to a waste toner bottle or a developing device and transported.

However, when a switching device for selectively transporting the toner recovered from the cleaning device to either the developing device or the waste toner bottle is provided in the recovery toner recovery path so far, In addition to the recycled toner transport path for transporting toner to the developing device, a separate and independent waste toner path for transporting to the waste toner bottle is required. For this reason, a drive system for transporting the collected toner along the waste toner path is installed independently of the drive system for the recycled toner transport path, or the waste toner path and the recycled toner transport path are the same drive system. It is necessary to have a configuration that operates in
When the drive system for the recycled toner conveyance path and the waste toner path is provided independently, only the necessary path can be operated independently, but the structure becomes complicated by adding the drive system. There was a problem of increase in size and cost.

On the other hand, when the configuration in which the recycled toner transport path and the waste toner path are operated by the same drive system is used, when only one of the paths is driven, for example, only the recycled toner transport path is driven for recycling. Even in such a case, the waste toner path that does not need to be operated is also driven, and the power consumption of the entire apparatus is unnecessarily increased.
In Patent Document 1 (Japanese Patent Laid-Open No. 2002-36595), for the purpose of switching and transporting the toner collected from the cleaning unit between the disposal side and the recycling side, a recycle toner transport unit is provided near one end of the recovery screw, and A configuration is disclosed in which a waste toner conveying means is provided near the other end of the collecting screw, and a collecting screw rotation direction switching control means for switching the conveying means is provided.
However, in Patent Document 1, since a drive system independent of the recycle drive system is provided in the toner disposal operation, the problem that the structure is complicated and the cost is not solved cannot be solved.

  The present invention has been made in view of the conventional problems as described above. In the configuration in which the untransferred toner collected from the image carrier by the cleaning device is selectively switched between the waste side and the recycle side. An object of the present invention is to provide a cleaning device and an image forming apparatus that can reduce power consumption without increasing the size, complexity, and cost.

  In order to achieve the above object, the cleaning device of the present invention removes the toner remaining on the image carrier after the toner image formed on the image carrier is transferred to the recording medium by the toner from the developing device. A cleaning device, a toner collecting / conveying means for conveying the collected toner removed from the image carrier, a drive source for the toner collecting / conveying means, and a conveying direction of the collected toner conveyed by the toner collecting / conveying means A direction-of-conveyance switching unit, a collected toner storage unit that stores the collected toner, a first collected toner transport unit that transports the collected toner to the developing device, and a transport of the collected toner to the collected toner storage unit A second collected toner conveying means, wherein the conveying direction switching unit conveys the collected toner conveyance destination to the developing device. A switching member that switches to either the collected toner conveyance path or the second collected toner conveyance path that conveys the collected toner to the collected toner storage means; and the first collected toner conveyance means that transmits a driving force transmission destination from the drive source; Or a transporting direction switching mechanism that switches to the second collected toner transporting unit, and at the same time as the switching of the collected toner transporting path by the switching member, the driving force transmission destination can be switched by the transporting direction switching mechanism. It is characterized by that.

  According to the present invention, the switching member for switching the transport destination of the toner collected from the cleaning device between the recycling side and the discarding side is provided, the drive transmission mechanism is provided on the switching member side, and one of the toner transports selected by the switching member is provided. By transmitting the driving force only first, it is possible to ensure the necessary toner conveying capability without simultaneously driving the entire conveying path in the cleaning device. For this reason, size reduction and cost reduction can be realized by reducing the number of parts.

1 is an internal configuration explanatory diagram of a color printer as an example of an electrophotographic image forming apparatus equipped with a cleaning device according to an embodiment of the present invention. FIG. It is an expansion schematic diagram showing the composition of an image creation part. It is a front view which shows schematic structure of the conveyance direction switching part which concerns on one Embodiment of this invention. (A) And (b) is the front view and side part longitudinal cross-sectional view of a conveyance direction switching part. (A) And (b) is the front view and side part longitudinal cross-sectional view of the recycle toner / waste toner switching mechanism which concern on other embodiment of this invention. 7 is a control flowchart for changing an interval or the like for discarding a collected toner amount according to the type of paper. 7 is a flowchart illustrating a control procedure when switching between a transport path to a developing device and a transport path to a waste toner bottle is determined based on a toner consumption index value consumed in image formation. 6 is a flowchart showing an embodiment in which the timing of switching the transport path from the recycled toner transport path to the waste toner transport path is matched with the timing of discharging the toner pattern on the image carrier. 7 is a flowchart for explaining a deteriorated toner discarding procedure using information on an image area ratio and paper type in combination.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
The following embodiments are preferred embodiments of the present invention, and the technical scope of the present invention is not limited to these embodiments unless otherwise specified to limit the present invention in the following description. .

FIG. 1 is an explanatory diagram of the internal configuration of a color printer as an example of an electrophotographic image forming apparatus equipped with a cleaning device according to an embodiment of the present invention. FIG. 2 is an enlarged schematic diagram showing the configuration of an image forming unit. is there.
The color printer (image forming apparatus) 1 has a configuration in which an image forming unit A, a paper feeding unit B, a paper discharging unit C, and a control unit (control means) D are arranged inside and outside the housing 2.
The image forming unit A includes a transfer belt 10 stretched endlessly by a plurality of rollers 11 and four image forming units 20 (a yellow image forming unit 20Y and a cyan image forming unit) arranged sequentially along the main running surface of the transfer belt. An image unit 20C, a magenta image forming unit 20M, a black image forming unit 20B), and a fixing device 35. Each image forming unit 20 includes a photosensitive drum (image carrier) 21, a charging unit 25 disposed on the outer periphery of the photosensitive drum, an exposure unit 26, a developing device 27, a transfer device 28, and a cleaning device 30. ing.

The paper feeding unit B disposed upstream of the image forming unit A takes out the paper feeding tray 40 that stores the recording media P in a stacked state and the recording media P on the paper feeding tray one by one from the top. A pickup roller 41 and the like for feeding toward the forming unit are provided. One recording medium fed by the pickup roller 41 passes through the roller pair 12, is fed to the nip portion of the roller pair 11 a, 13, and is conveyed upward along the main running surface of the transfer belt 10. An image forming unit 20 (yellow image forming unit 20Y, cyan image forming unit 20C, magenta image forming unit 20M, black image forming unit 20B) of each color is sequentially arranged on the main running surface of the transfer belt 10, and the recording medium P In the process of passing through each image forming unit, the toner image of each color is transferred.
The fixing device 35 disposed on the downstream side of the image forming unit A includes a pressure roller 36 and a heating roller 37, and fixes the toner image by heating the toner image on the recording medium passing between the two rollers while applying pressure. Do.
The paper discharge unit C includes a paper discharge tray 39 for storing the fixed recording paper discharged by the paper discharge roller pair 38.

  In the image forming operation in the image forming unit A, the photosensitive member 21 rotating in the direction of the arrow is first uniformly charged by the charging unit 25, and then the potential is partially lowered by irradiation of light from the exposure unit 26 to statically. An electrostatic latent image is formed. When this electrostatic latent image reaches the developing device 27 (developing sleeve 27a) and comes into contact with the toner layer, the charged toner adheres to become a toner image, and when the electrostatic latent image reaches the position of the transfer device 28, Transferred onto the recording medium P. This image forming operation is performed in the same manner in each color image forming unit 20 (yellow image forming unit 20Y, cyan image forming unit 20C, magenta image forming unit 20M, black image forming unit 20B). Is transcribed onto. The superimposed toner image on the recording medium that has passed through the black image forming portion 20 </ b> B due to the movement of the transfer belt 10 is fixed on the recording medium P when passing through the fixing device 35.

Next, FIG. 2 is an enlarged view showing the configuration of the image forming unit including the cleaning device.
The cleaning device 30 removes toner remaining on the photosensitive member 21 without being completely transferred onto the recording medium P in the transfer device 28, and cleans the surface of the photosensitive member 21.
The cleaning device 30 of the present embodiment includes a cleaning case 50, a cleaning blade 51, and a toner recovery coil (toner recovery / conveying means) 52. The cleaning case 50 is disposed so as to face the surface of the photoreceptor 21 whose opening rotates in the direction of the arrow. The cleaning blade 51 is supported by the cleaning case 50 so as to be in sliding contact with the surface of the photoreceptor 21 through the opening.
The cleaning blade 51 is made of an elastic body such as a rubber member, and is long in the front and back directions of FIG. The leading edge (edge portion) of the cleaning blade comes into contact with the surface of the photoconductor 21 so as to be in the counter direction with respect to the rotation of the photoconductor 21.

Next, the cleaning process by the cleaning device will be described.
In the cleaning case 50, the residual toner on the surface of the photosensitive member 21 is cleaned by the cleaning blade 51, is damped, and accumulates along the edge of the cleaning blade. When the amount of residual toner accumulated on the cleaning blade reaches a certain height, it is transported in the direction perpendicular to the paper surface by the toner recovery coil 52 and transported outside the cleaning device.
In the present invention, there is provided a switching member that can alternately switch the destination of the collected toner conveyed by the toner collecting coil 52 of the cleaning device 30 between the recycling side and the disposal side. Furthermore, by providing a single drive transmission means on the switching member side and transmitting the drive only to the side selected as the toner transport destination, the necessary toner transport capability can be achieved without simultaneously driving the entire transport path in the apparatus. The structure that ensures the above is characteristic.

FIG. 3 is a front view illustrating a schematic configuration of the transport direction switching unit 8 (recycled toner / waste toner switching mechanism 80) according to the embodiment of the present invention, and FIGS. 4A and 4B illustrate the transport direction. It is the front view of a switching part, and a side part longitudinal cross-sectional view.
The image forming apparatus 1 according to the present invention includes an image carrier 21, a developing device 27 that forms a toner image on the image carrier, a transfer device 28 that transfers the toner image to a recording medium P, and the image carrier 21 after transfer. A cleaning device 30 that removes toner remaining on the toner, a toner collection and conveyance unit 52 that conveys the collected toner removed from the image carrier by the cleaning device to the outside of the cleaning device, a drive source of the toner collection and conveyance unit, and a collected toner Collected toner storage means (waste toner storage container), first recovered toner transport means 82a for transporting recovered toner to the developing device, and second recovered toner transport means for transporting recovered toner to the recovered toner storage means 83a and the second destination for transporting the collected toner to the first collected toner conveying path 82 for conveying to the developing device 27 or the collected toner storing means. A switching member 81 for switching to either one of the toner collection path 83 and a recycled toner / waste toner for switching the driving force transmission destination from the driving source to the first collected toner conveying means 82a or the second collected toner conveying means 83a A configuration including a switching mechanism (conveying direction switching mechanism) 80 is characteristic. Further, it is characteristic that the transfer destination of the driving force can be switched by the transport direction switching mechanism 80 along with the switching of the collected toner transport path.

Further, the cleaning device 30 according to the present invention has been transported by the toner recovery transport unit 52 that transports the recovered toner removed from the image carrier 21, the drive source of the toner recovery transport unit, and the toner recovery transport unit 52. A transport direction switching unit 8 that switches the transport direction of the collected toner, a collected toner storage unit (not shown) that stores the collected toner, a first collected toner transport unit 82a that transports the collected toner to the developing device, and a collected toner that has been collected. And a second collected toner conveying means 83a for conveying to the storing means.
The transport direction switching unit 8 switches the transport destination of the recovered toner to either the first recovered toner transport path 82 that transports the recovered toner to the developing device 27 or the second recovered toner transport path 83 that transports to the recovered toner storage unit. A switching member 81, a recycled toner / waste toner switching mechanism (conveying direction switching mechanism) 80 for switching a driving force transmission destination from a driving source to the first collected toner conveying means 82a or the second collected toner conveying means 83a, Is provided. Further, it is characterized in that the transmission destination of the driving force can be switched by the transport direction switching mechanism simultaneously with the switching of the collected toner transport path by the switching member 81.

A recycled toner / waste toner switching mechanism (carrying direction switching mechanism) 80 is configured to transfer a toner collected by the cleaning apparatus main body to a recycled toner transport path (first recovered toner transport path) 82 and a waste toner transport path (first). 2 to collect recovered toner transport path) 83.
The toner collected by the cleaning device 30 is transported by the toner recovery coil 52 and sent to the transport direction switching unit 8 adjacent to the cleaning device.
The transport direction switching unit 8 is provided with a recycle / disposal switch member (hereinafter referred to as a switch member) 81, and the collected toner is distributed to the recycle toner transport path 82 and the waste toner transport path 83 by the operation of the switch member 81.

Next, the configuration of the transport direction switching unit 8 and the recycling / disposal operation will be described below.
The conveyance direction switching unit 8 is fixed to one end of the toner collection coil 52 and is rotatable by a shaft 81a and a drive gear 90 that transmits a driving force from a motor (not shown) to the toner collection coil 52 (shaft portion 52a). A switching member 81 that opens the recycled toner conveyance path 82 when it is supported and is at the position indicated by the solid line in FIG. 3 and opens the waste toner conveyance path 83 when it is at the position indicated by the broken line, and the switching member 81 is rotated. A driving means such as a solenoid (not shown) to be provided (provided on the shaft 81a of the switching member) and a driving force from the driving gear 90 are arranged, and the shaft center 81a of the switching member 81 is rotatable about the axis. The intermediate gear 91 that is supported and the switching member 81 or a rotating member 81A that rotates together with the switching member are rotatably supported by the intermediate gear 91. A movable gear 94 that constantly meshes and receives transmission of driving force, and a recycled toner transport drive gear (first transport drive gear) 92 that drives a coiled recycled toner transport means (first recovered toner transport means) 82a; And a waste toner transport drive gear (second transport drive gear) 93 for driving a coil-shaped waste toner transport means (second recovered toner transport means) 83a. The movable gear 94 meshes only with the recycled toner transport drive gear 92 when the switching member 81 is at the recycle toner transport path open position indicated by the solid line, and when the switching member 81 is at the waste side path open position indicated by the chain line, the waste toner transport drive is performed. Only meshed with the gear 93.

The rotation member 81A is integrated with the shaft portion 81a of the switching member 81, and rotatably supports the movable gear 94 by a bearing portion provided at an appropriate position below the rotation member 81A. The movable gear 94 is configured to rotate integrally with the switching member 81.
The toner conveyed to the outside of the cleaning device by the toner recovery coil 52 falls vertically from the inlet and is sent to the conveyance direction switching unit 8. A recycle / disposal switching member (switching member) 81 is provided in the transport direction switching unit 8. The switching member 81 is rotatably held by a support member such as the cleaning case 50, and rotates in the forward and reverse directions around the shaft portion 81a as a fulcrum to change the path of the collected toner to either the recycled toner conveyance path or the waste toner path. Switch to either. The position (rotation angle) of the switching member is switched by driving means such as a solenoid, and the posture is maintained after switching.

The recycled toner conveyance path 82 is connected to the developing device 27, and the waste toner path 83 is connected to a waste toner storage container (collected toner storage means) (not shown).
At the time of the recycling operation, the switching member 81 rotates clockwise to be in a state indicated by a solid line in FIG. 3, and the recycled toner transport path 82 is set to Open and the waste toner path 83 is set to Close, whereby the collected toner is transported to the recycled toner. It is sent to the developing device 27 via a path 82.
During the discarding operation, the switching member 81 rotates counterclockwise from the position indicated by the solid line and enters the state indicated by the chain line. The recycled toner transport path 82 is set to Close, and the waste toner path 83 is set to Open. It is conveyed to the waste toner path 83.

Next, the switching operation of the switching member will be described based on FIG.
A driving force from a motor (not shown) is input through a driving gear 90 to the collecting coil 52 that conveys the collected toner generated in the cleaning device 30 to the outside of the device.
Recycle toner transport means 82a and waste toner transport means 83a are also provided at the transport destination on the recycled toner transport path side and the waste toner path side, which are transport destinations of the collected toner by the recovery coil 52, respectively. Recycled toner transport drive gear 92 and waste toner transport drive gear 93 are also assembled to each toner transport means 82a and 83a.

A driving force is selectively input from the recovery coil driving gear 90 to the recycled toner conveying unit 82a or the waste toner conveying unit 83a via an intermediate gear 91 provided on the switching member 81. In this example, the intermediate gear 91 is axially supported by the shaft portion 81a that is the rotation fulcrum of the switching member 81, but is rotated without being affected by the switching operation of the switching member 81 and the switching position. That is, the rotation of the intermediate gear 91 is not transmitted to the switching member 81.
That is, although the rotation fulcrum of the intermediate gear 91 and the switching member 81 is the same, the intermediate gear 91 is configured to be rotatable regardless of the rotation angle of the switching member 81 by providing the intermediate gear 91 with a bearing (not shown). . That is, the intermediate gear 91 only transmits the driving force to the movable gear 94 and does not affect the rotation angle of the switching member 81.
The movable gear 94 rotatably supported at the tip of the switching member 81 changes the object (gears 92 and 93) to which the drive is transmitted depending on the position. That is, when the rotation angle position of the switching member 81 is changed, the drive is input to only one of the recycled toner transport unit 82a (gear 92) and the waste toner transport unit 83a (gear 93), and the other is driven. It is the composition which is not done. For this reason, the number of parts can be reduced, the structure of the drive mechanism can be simplified, and the size and occupied area can be reduced.

Next, details of driving when the toner is transported to the recycled toner transport path side will be described.
During the recycling operation, the switching member 81 rotates clockwise, the recycled toner transport path 82 is Open, and the waste toner path 83 is Close. At this time, the recycled toner transport driving gear 92 is driven from the driving gear 90 via the intermediate gear 91 and the movable gear 94. At this time, the movable gear 94 is positioned away from the waste toner conveyance drive gear 93.

Next, details of driving when the toner is conveyed to the waste toner path 83 side will be described.
During the discarding operation, the switching member 81 rotates counterclockwise, the recycled toner transport path 82 becomes Close, and the waste toner path 83 becomes open. At this time, the waste toner conveyance drive gear 93 is driven from the drive gear 90 via the intermediate gear 91 and the movable gear 94. The movable gear 94 is separated from the recycled toner conveyance drive gear 92.
With the above-described configuration, it is possible to input a driving force only to a transport unit (recycled toner transport unit 82a or waste toner transport unit 83a) to which the collected toner is to be sent. For this reason, the energy consumption of the image forming apparatus can be reduced by the drive load on the side not in use. As a result, the power consumption of the motor used for driving can be greatly reduced as compared with the case where the entire region is driven simultaneously. In addition, since the driving force is transmitted from the common driving source for driving the recovery coil 52 to each toner conveying unit, it is not necessary to provide the conveying driving unit individually for each conveying path.
Further, if the simple configuration in which the recycled toner conveyance path 82 is directly connected to the developing device 27, the recycled toner conveyance means 82a and the recycled toner conveyance drive gear 92 are not necessary, so that the cost of the entire apparatus can be reduced. It becomes possible. With such a configuration, the waste toner transport unit 83a may be operated only when it is necessary to send toner to the waste toner transport path side.
In the above embodiment, the drive input direction from a drive source such as a motor is switched by moving the movable gear 94, but it is also possible to switch the presence or absence of drive input by using a clutch without using the movable gear. .

FIGS. 5A and 5B are a front view and a side longitudinal sectional view of a recycled toner / waste toner switching mechanism according to another embodiment of the present invention.
In this embodiment, the configuration is further simplified by omitting the movable gear 94 used in the above embodiment.
In addition, the same code | symbol is attached | subjected to FIG. 4 and an identical part, and the overlapping description is abbreviate | omitted.

The conveyance direction switching mechanism 80 according to the present embodiment omits the movable gear 94 in the embodiment of FIG. 4 and always meshes the intermediate gear 91 with the recycled toner conveyance drive gear 92 and the waste toner conveyance drive gear 93. Yes. Further, a recycle side clutch 92a is disposed between the recycle toner transport drive gear 92 and the recycle toner transport means 82a, and a waste side clutch 93a is disposed between the recycle toner transport drive gear 93 and the waste toner transport means 83a. The transmission of the driving force from the gear to each conveying means can be arbitrarily connected and disconnected.
That is, the transport direction switching mechanism 80 is rotated by the drive gear 90 that transmits the driving force from the drive source to the toner recovery transport means 52 (shaft portion 52a), and the first recovery toner transport path 82 and the first transport mechanism 90 by rotating. A switching member 81 that selectively (selectively) opens (closes) the two recovered toner conveyance paths 83, a driving unit that independently rotates the switching member, and a driving force from the driving gear 90. An intermediate gear 91 rotatably supported by a bearing portion provided in a cleaning case, etc., a first conveyance driving gear 92 that always meshes with the intermediate gear and drives the first recovered toner conveyance means 82a, A second transport drive gear 93 that is always meshed with the gear 91 and drives the second recovered toner transport means 83a, and is disposed between the first transport drive gear 92 and the first recovered toner transport means 82a. Resai Comprising a Le clutch (first clutch) 92a, and a waste side clutch (second clutch) 93a disposed between the second transfer drive gear and the second recovery toner conveying means 83a. Further, the recycle side clutch 92a and the discard side clutch 93a are selectively (alternatively) operated by the control from the control unit D, so that the drive gear 90 shifts to the first transport drive gear and the second transport drive gear. The transmission of the driving force can be arbitrarily connected and disconnected.

  According to this configuration, the control unit D switches from the drive gear 90 to the intermediate gear 91 by performing switching control in which one of the recycle side clutch 92a and the discard side clutch 93a is in the connected state and the other is in the disconnected state. The transmitted driving force can be transmitted to only one of the recycled toner transport driving gear 92 and the waste toner transport driving gear 93. As a result, only one of the recycled toner conveying means 82a and the waste toner conveying means 83a can be driven to selectively switch the collected toner conveying destination.

Next, in an image forming apparatus that performs toner recycling to reduce running costs, the operation of returning the collected toner back into the developing device is repeated, so that foreign matter such as paper dust on the paper (recording medium) is removed. It accumulates in the developing device, cleaning device, and transport path. If foreign matter such as paper dust is generated together with toner, it may cause abnormal images such as white spots. Therefore, the toner is periodically discarded and the foreign matter is removed from the developing device, cleaning device, and transport path. There is a need. For this reason, it is effective to adopt a configuration in which the conveyance direction can be changed depending on the type of paper that uses the interval for discarding the toner (the amount of paper dust generated). Specifically, the interval, frequency, and toner amount for discarding the collected toner can be changed depending on the type of paper. For example, when a sheet with a large amount of paper dust is used, control is performed so that the period during which the collection toner transport destination is switched to the waste toner transport path 83 is long.
As for the paper type, for example, when image data is transmitted from an external device to the image forming apparatus, it may be sent as information on the paper type, material, and amount of dust generated, or the operator may change the paper. It may be input as data each time.

FIG. 6 is a control flowchart for changing the interval of discarding the collected toner amount according to the type of paper.
With the start of the image forming operation, the paper P is fed from the paper feeding unit B to the image forming unit A (S1, S2). At this time, the paper type (the amount of paper dust) is input to the control unit D by data transmission from the host machine or input to the image forming apparatus (S3). If the paper is low in paper dust, the transport direction switching unit 8 is controlled at a normal interval to switch between the recycled toner transport path 82 and the waste toner transport path 83 (S4, S5).
On the other hand, when passing paper with a lot of paper dust, the amount of waste toner per unit time is reduced by changing the transport interval so that the amount of collected toner transported to the waste toner transport path 83 is increased. The conveyance direction switching unit 8 is controlled so as to increase (S4, S6).

Next, under the condition that the image area to be formed is small and the amount of toner consumption is small, the time during which the developer is stirred in the developing device becomes long and deteriorates, causing toner scattering and the like. For this reason, it is effective to adopt a configuration in which the interval, frequency, and amount of toner to be discarded can be changed according to image conditions. Specifically, for example, it is effective to determine switching between the transport path to the developing device and the transport path to the waste toner bottle based on the toner consumption index value consumed in image formation.
As the toner consumption index value, for example, it is conceivable to use an image area ratio at a predetermined number of image formations. That is, the control unit (control unit) D calculates the image area ratio for each predetermined number of image formations based on the image information used for emitting laser light in the exposure unit (optical scanning device) 26 and calculates the image area ratio. The image area ratio is stored in the memory. The control unit D functions as an image area rate calculation unit, and the control unit D or the memory functions as an image area rate storage unit. When the calculated image area ratio reaches a specified value, the transport path is switched from the recycled toner transport path (developing device) to the waste toner path. By this control, toner containing a large amount of paper dust can be discarded without being recycled.

FIG. 7 is a flowchart showing a control procedure for determining switching between the transport path to the developing device and the transport path to the waste toner bottle based on the toner consumption index value consumed in image formation.
Simultaneously with the start of the image forming operation, the paper P is fed from the paper feeding unit B to the image forming unit A and image formation is started (S11). The control unit D calculates an image area ratio for each predetermined number of image forming operations (S12). If the calculated image area ratio does not reach the predetermined value, the collected toner is transferred to the recycled toner transfer path 82. Continue (S13, S14). When the calculated image area ratio reaches a predetermined value, the conveyance direction switching unit 8 is controlled to convey the collected toner to the waste toner conveyance path 83 (S13, S15).
Information about the image area ratio and the type of paper (the amount of paper dust) may be used together.
In other words, in the case of a paper with a small image area ratio and a large amount of paper dust, an abnormal image can be prevented by shortening the interval until the disposal is performed. By increasing the interval, the running cost can be reduced.

Next, FIG. 8 shows an embodiment in which the transport path switching timing (conveyance path switching condition) from the recycled toner transport path to the waste toner transport path is matched with the discharge toner pattern formation timing on the image carrier. ing.
The image forming apparatus according to the present embodiment removes the discharge pattern as a toner image formed on the image carrier 21 constituting the image forming unit A by the cleaning device 30 without transferring it onto the recording medium, and collects the collected toner. A discharge pattern forming mode for storing in the storage means is provided. Then, at the time of switching to the discharge pattern forming mode, the transport direction switching unit 8 switches from the first recovered toner transport path 82 to the second recovered toner transport path 83.

In the apparatus configuration of the present invention shown in FIGS. 3 to 5, a first collected toner conveyance path (recycled toner conveyance path) 82 and a second collected toner conveyance path (waste toner conveyance path) 83 are mutually connected. With the configuration in which the conveyance path is switched, the toner conveyance amount to the developing device and the toner storage unit can be changed.
That is, when the image forming operation is repeated with a print pattern having a very low image area ratio, the amount of New toner replenished from the toner cartridge to the developing device becomes minute, and the state in which the toner in the developing device is not replaced continues. If this state continues, the developer is likely to be deteriorated due to stress such as stirring by the stirring member in the developing device.
As a countermeasure against the deteriorated toner, an operation of performing only image formation on the image carrier without passing paper after passing a certain recording medium through the image carrier and before passing the next recording medium. Is carried out. In this operation, for example, a belt-like discharge pattern is formed in the longitudinal direction on the image carrier, and the discharge pattern is removed by the cleaning device and conveyed (discarded) to the toner storage unit. This deteriorated toner discarding method is often used in a color MFP (Multi-Function Printer) that does not have a recycling mechanism for the developing device.
If this deteriorated toner processing configuration is used, in the case of a low image area ratio, a discharge pattern is created for every 100 images, and the deteriorated toner removed and collected from the image carrier is stored in the toner storage means. In the case of a high image area ratio, an operation of recycling to a developing device is possible. Accordingly, it is possible to reduce the running cost and to discard the deteriorated toner that leads to the abnormal image without recycling it, thereby preventing the abnormal image.

The degraded toner disposal procedure will be described based on the flowchart of FIG.
With the start of the image forming operation, the paper P is fed from the paper feeding unit B to the image forming unit A (S20). Next, the control unit D calculates an image area ratio for each predetermined number of image formation (S21). The calculation of the image forming area rate follows the procedure described for step 12 in the embodiment of FIG.
In step 22, the control unit D determines whether or not the calculated image area ratio has reached the specified value. If the calculated image area ratio has not reached the specified value, the collected toner is used as the first toner. It continues to be transported to the collected toner transport path (recycled toner transport path) 82 (S23). When the calculated image area ratio reaches a predetermined value, a discharge pattern image is formed on the image carrier, and after removing this, the recovered toner is transferred to the second recovered toner transport path (waste toner transport path). ) The conveyance direction switching unit 8 is controlled so as to be conveyed to 83 (S24).
In an image forming apparatus (not shown) of a type in which a toner image on each image carrier is transferred onto an intermediate transfer belt and then transferred onto a recording medium in a secondary transfer unit, the discharge on the image carrier is performed. Without transferring the pattern to the intermediate transfer belt, the pattern is removed by the cleaning device 30 and then conveyed to the second collected toner conveyance path.
In addition to the method of using the information about the image area ratio described in FIG. 8 as a countermeasure against the deteriorated toner when the image forming operation is repeated with a print pattern having a very low image area ratio, a recording medium (paper) You may use together the information about the kind (the number of paper dust).
In other words, in the case of a paper with a small image area ratio and a large amount of paper dust, an abnormal image can be prevented by shortening the interval until the disposal is performed. By increasing the interval, the running cost can be reduced.

Based on the flowchart of FIG. 9, a deteriorated toner discarding procedure using information on the image area ratio and the paper type will be described.
First, a paper type (paper classification based on the amount of paper dust) is input to the control unit D by data transmission from the host machine or input to the image forming apparatus (S30). With the start of the image forming operation, the paper P is fed from the paper feeding unit B to the image forming unit A (S31).
When setting the paper classification, a method is generally used in which the operator changes the paper classification and changes the image forming condition. However, the switching in this embodiment also matches the setting of the paper classification. Switching may be performed.
In step 32, the control unit D determines the amount of paper dust (paper classification) generated when the paper is passed based on the paper classification to which the paper to be used belongs.
At this time, if the paper is a small amount of paper dust, the conveyance direction switching unit 8 is controlled so as to be conveyed to the first collected toner conveyance path (recycled toner conveyance path) 82 (S33).

On the other hand, when a sheet containing a large amount of paper dust is passed, the conveyance direction switching unit 8 is controlled so as to be conveyed to the second collected toner conveyance path (waste toner conveyance path) 83 (S34).
By using the control based on the above paper classification together with the control based on the area ratio of FIG. 8, the amount of waste toner can be appropriately controlled.
It is also possible to perform switching based on only information relating to the type of paper, not in combination with the image area ratio. Reduces running costs by switching to recycled paper, such as recycled paper, which is transported to the toner storage means and recycled to the developing device when paper with low paper dust, such as plain paper or coated paper, is used. Thus, abnormal images can be prevented by minimizing the mixing of foreign matters such as paper dust.

[Summary of Configuration, Action, and Effect of the Present Invention]
The cleaning device 30 according to the first aspect of the present invention removes the toner remaining on the image carrier after the toner image formed on the image carrier 21 is transferred to the recording medium P by the toner supplied from the developing device 27. It is a means to remove. The cleaning device 30 includes a toner collection / conveying unit 52 that conveys the collected toner removed from the image carrier, a driving source of the toner collection / conveying unit, and a conveyance direction of the collected toner conveyed by the toner collection / conveying unit 52. A transport direction switching unit 8 for switching, a collected toner storage unit for storing the collected toner, a first collected toner transport unit 82a for transporting the collected toner to the developing device, and a second for transporting the collected toner to the collected toner storage unit And a collected toner conveying means 83a. Further, the conveyance direction switching unit 8 is a switching member that switches to either the first collected toner conveyance path 82 that conveys the collected toner to the developing device or the second collected toner conveyance path 83 that conveys the collected toner to the collected toner storage unit. 81, and a conveyance direction switching mechanism 80 that switches the destination of the driving force from the drive source to the first collected toner conveying means 82a or the second collected toner conveying means 83a. Further, the drive force transmission destination can be switched by the transport direction switching mechanism 80 simultaneously with the switching of the collected toner transport path by the switching member 81.
Note that the configuration may be further simplified by directly connecting the first collected toner conveyance path to the developing device.
According to this, in the configuration in which the untransferred toner (collected toner) collected from the image carrier by the cleaning device is selectively switched between the disposal side and the recycling side, the configuration is increased in size, complexity, and cost is increased. Power consumption can be reduced without incurring.
Note that, by switching the route for transporting the collected toner, the toner transport amount to the developing device and the toner transport amount to the collected toner storage unit can be made different.

In the cleaning device according to the second aspect of the present invention, the conveyance direction switching mechanism 80 includes a drive gear 90 that transmits the driving force from the driving source to the toner collection and conveyance means, the first collection toner conveyance path, and the second collection toner. A switching member 81 that selectively opens the conveyance path, a driving unit that rotates the switching member, an intermediate gear 91 that is arranged to receive a driving force from the driving gear 90, and the switching member 81 are integrated. , A movable gear 94 that is always meshed with the intermediate gear and receives a driving force, a first conveyance driving gear 92 that drives the first collected toner conveying means, and a second collected toner conveying means And a second transport drive gear 93 for driving. Further, the movable gear 94 meshes with the first conveyance drive gear when the switching member opens the first collection toner conveyance path, and the second gear when the switching member opens the second collection toner conveyance path. It is characterized by meshing with a conveyance drive gear.
According to this, since the respective conveying means 8a and 83a are selectively driven using the movable gear 94 that rotates in conjunction with the switching member 81, the number of parts constituting the driving force transmission path is reduced. Therefore, it is possible to reduce the size and cost.

In the cleaning device according to the third aspect of the present invention, the conveyance direction switching mechanism 80 includes a drive gear 90 that transmits the driving force from the driving source to the toner collection and conveyance means, the first collection toner conveyance path, and the second collection toner. A switching member 81 that selectively opens the conveyance path, a driving means that rotates the switching member, an intermediate gear 91 that is arranged to receive the driving force from the driving gear, and the intermediate gear are always meshed with each other. A first transport driving gear 92 that drives the first recovered toner transport means, a second transport drive gear 93 that always meshes with the intermediate gear and drives the second recovered toner transport means, and a first transport A first clutch 92a disposed between the drive gear and the first collected toner transport means, and a second clutch 93a disposed between the second transport drive gear and the second collected toner transport means. And comprising. Furthermore, by selectively operating the first clutch and the second clutch, transmission of driving force from the drive gear to the first transport drive gear or the second transport drive gear can be arbitrarily connected and disconnected. It is characteristic that it was configured.
According to this configuration, since the movable gear 94 can be omitted, the configuration can be simplified and the cost can be reduced.
By adopting the image forming unit provided with the cleaning device of the present invention, the configuration of the image forming device can be simplified.

The image forming apparatus of the present invention determines the switching timing of the transport destination of the collected toner by the transport direction switching unit based on the type of recording medium to be passed and / or the image area ratio for each number of image forming operations in the image forming unit. Control means is provided.
If foreign matter such as paper dust is generated together with toner, it may cause abnormal images such as white spots. Therefore, the toner is periodically discarded and the foreign matter is removed from the developing device, cleaning device, and transport path. There is a need. When image formation is performed using a recording medium made of a material that generates a large amount of paper dust or the like, increasing the amount of toner to be discarded is effective in maintaining the image quality, so the interval for performing the disposal operation is shortened. To do.
It is also effective for maintaining the image quality to determine the switching timing of the transport destination of the collected toner based on the amount of image area ratio for each number of image formations in the image forming unit.

The image forming apparatus of the present invention removes the discharge pattern as a toner image formed on the image carrier 21 constituting the image forming portion A by the cleaning device 30 according to claim 1 without transferring the discharge pattern. And a discharge pattern forming mode for storing in the collected toner storage means. When switching to the discharge pattern forming mode, the transport direction switching unit 8 switches from the first recovered toner transport path 82 to the second recovered toner transport path 83 when switching to the discharge pattern forming mode. It is characterized by that.
An image area ratio is calculated, and when the image area ratio reaches a predetermined value, a discharge pattern image as a toner image is formed on the image carrier and removed by a cleaning device (cleaning member 51). The collected toner is conveyed to a second collected toner conveyance path (waste toner conveyance path) 83.
As a countermeasure against the deteriorated toner when the image forming operation is repeated with a print pattern having a very low image area ratio, the type of the recording medium (paper) (the amount of paper dust) ) May be used in combination. Further, a countermeasure against deteriorated toner using a discharge pattern image may be implemented based on information on only the type of recording medium.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 8 ... Conveyance direction switching part, 10 ... Transfer belt, 11 ... Roller, 2 ... Case, 20 ... Image forming part, 20B ... Black image forming part, 20C ... Cyan image forming part, 20M ... Magenta Image forming section, 20Y ... Yellow image forming section, 21 ... Photoconductor (image carrier), 25 ... Charging section, D ... Control section (control means), 26 ... Exposure section, 27 ... Developing device, 27a ... Developing sleeve, 28 ... Transfer device, 30 ... Cleaning device, 35 ... Fixing device, 36 ... Pressure roller, 37 ... Heating roller, 38 ... Discharge roller pair, 39 ... Discharge tray, 40 ... Feed tray, 41 ... Pickup roller, DESCRIPTION OF SYMBOLS 50 ... Cleaning case, 51 ... Cleaning blade (cleaning member), 52 ... Toner collection coil (toner collection conveyance means), 80 ... Recycle toner / waste toner switching mechanism (conveyance direction switching mechanism) 81... Recycle / Discard switching member (switching member), 81 a... Shaft, 82... Recycled toner transport path (first recovered toner transport path), 82 a... Recycled toner transport means (first recovered toner transport means), 83 ... Waste toner transport path (second recovered toner transport path), 83a ... Waste toner transport means (second recovered toner transport means), 90 ... Recovery coil drive gear (drive gear), 91 ... Intermediate gear, 92 ... Recycle Toner transport drive gear (first transport drive gear), 92a... Recycle side clutch, 93... Waste toner transport drive gear (second transport drive gear), 93a.

JP 2002-36595 A

Claims (6)

A cleaning device for removing toner remaining on the image carrier after transferring a toner image formed on the image carrier to a recording medium with toner from a developing device;
A toner collecting / conveying means for conveying the collected toner removed from the image carrier, a driving source for the toner collecting / conveying means, and a conveying direction switching unit for switching a conveying direction of the collected toner conveyed by the toner collecting / conveying means; A recovered toner storage means for storing the recovered toner; a first recovered toner transport means for transporting the recovered toner to the developing device; and a second recovered toner for transporting the recovered toner to the recovered toner storage means. A conveying means,
The transport direction switching unit switches the transport destination of the recovered toner to one of a first recovered toner transport path for transporting to the developing device and a second recovered toner transport path for transporting to the recovered toner storage unit. A switching member, and a conveyance direction switching mechanism that switches a destination of driving force from the drive source to the first collected toner conveying means or the second collected toner conveying means,
The cleaning apparatus is configured to be capable of switching a driving force transmission destination by a transport direction switching mechanism simultaneously with switching of the collected toner transport path by the switching member. The transport direction switching mechanism selectively opens the drive gear that transmits the driving force from the drive source to the toner recovery transport unit, the first recovery toner transport path, and the second recovery toner transport path. A switching member to be rotated, a driving means for rotating the switching member, an intermediate gear arranged to receive a driving force from the driving gear, a rotating member integrally with the switching member, and the intermediate gear; A movable gear that is always meshed and receives transmission of driving force, a first transport drive gear that drives the first collected toner transport means, and a second transport drive gear that drives the second recovered toner transport means. And comprising
The movable gear meshes with the first transport driving gear when the switching member opens the first collected toner transport path, and when the switching member opens the second recovered toner transport path. The cleaning device according to claim 1, wherein the cleaning device meshes with a second conveyance drive gear. The conveyance direction switching mechanism alternatively selects a drive gear for transmitting a driving force from the drive source to the toner collection and conveyance means, the first collection toner conveyance path, and the second collection toner conveyance path. A switching member to be opened, a driving means for rotating the switching member, an intermediate gear arranged to receive a driving force from the driving gear, and the intermediate gear always meshed with each other, and the first collected toner transport A first transport drive gear that drives the second transporting gear, a second transport drive gear that always meshes with the intermediate gear and drives the second collected toner transport device, the first transport drive gear, and the first transport gear. A first clutch disposed between the second toner recovery means and a second clutch disposed between the second transport driving gear and the second recovered toner transport means,
The first clutch and the second clutch are selectively operated to arbitrarily connect or disconnect the driving force from the drive gear to the first transport drive gear or the second transport drive gear. The cleaning device according to claim 1, wherein the cleaning device is configured to be capable of performing the above. An image forming unit,
An image forming apparatus comprising the cleaning device according to claim 1 in the image forming unit.   Control means for determining the timing of switching the transport destination of the collected toner by the transport direction switching unit based on the type of recording medium to be passed and / or the image area ratio for each number of image formations in the image forming unit. The image forming apparatus according to claim 4. 4. The collected toner storage means removed by the cleaning device according to claim 1 without transferring a discharge pattern as a toner image formed on an image carrier constituting the image forming unit. 5. Equipped with a discharge pattern forming mode
6. The switch according to claim 4, wherein at the time of switching to the discharge pattern forming mode, the transport direction switching unit switches the first recovered toner transport path to the second recovered toner transport path. Image forming apparatus.

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