JP3784115B2 - Collected toner transfer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus of an electrophotographic system, in particular, an image forming body such as a photosensitive member or an intermediate transfer member, and a transfer belt used in a printer, a facsimile machine, a copying machine or the like using a two component developer or a one component developer. The present invention relates to a transfer conveying member cleaning means such as a transfer toner and a recovered toner transfer device for transferring toner recovered by the cleaning means to a developing device.
[0002]
[Prior art]
In an image forming apparatus having a cleaning unit that cleans and collects residual toner after image formation on a photoconductor, an image forming body, a transfer conveyance body, and the like, a collected toner storage unit or development provided separately from the cleaning unit As the toner collecting means for collecting toner from the cleaning means in the apparatus, there are the following techniques (1) and (2).
[0003]
(1) A recovered toner discharge portion of a cleaning device as a cleaning means and a recovered toner storage means provided separately from the cleaning device are connected by a pipe, and a cleaning device is provided by a coil screw provided in the pipe. Technology for collecting the collected toner collected in the collected toner storage means.
[0004]
(2) A technique in which the collected toner storage means is disposed in the vicinity of the collected toner discharge portion of the cleaning device, and the collected toner is transferred to the collected toner storage means mainly by gravity.
Further, although not known, as a proposed technique, instead of the coil screw, as a pump capable of transferring powder, a rotor that moves toner in an axial direction by rotating, and a rotor that wraps the rotor And a technique using a screw pump, commonly known as a MONO pump, having an air passage of the rotor and a fixed stator in contact engagement with the rotor, and air for fluidizing the toner There is a recovered toner transfer device having an air supply means for supplying to the screw pump.
[0005]
With such a technique, the collected toner can be reused, and the copy cost can be greatly reduced.
[0006]
[Problems to be solved by the invention]
Conventionally, a powder pump and air supply means constituting a collected toner transfer device are continuously operated together with an image forming apparatus.
For this reason,
(1). High temperature blocking of the toner occurs due to the heat generated by the moving part, or it has hindered reliable toner transfer due to toner fluidity deterioration,
(2). In some cases, the collected toner cannot be reused due to thermal stress.
(3). There was a problem that the performance of the powder pump and the air supply means deteriorated early.
[0007]
Therefore, the present invention may cause high-temperature blocking of the toner due to heat generation of the movable part, obstructing the reliable toner transfer due to toner flow deterioration, and the recovered toner cannot be reused due to thermal stress. Provides a recovered toner transfer device that eliminates problems such as early deterioration in performance of powder pumps and air supply means, enables reuse of recovered toner, and reduces wear on various members The purpose is to do.
[0008]
[Means for Solving the Problems]
In order to achieve the object, the present invention has the following configuration.
[0009]
(1) A collected toner transfer device provided in the image forming apparatus, the cleaning means for cleaning and collecting the residual toner of the image forming apparatus, and the recovered toner collected by the cleaning means are transferred to the developing device. A recovered toner supply means, the recovered toner supply means comprising a powder pump, an air supply means and a toner collecting device, the powder pump rotating to move the toner in the axial direction; A fixed stator that contacts and engages so as to enclose the rotor, and the air supply means is a recovered toner transfer device that supplies air to fluidize the toner to the powder pump, and the toner The collecting device separates the collected toner from the powder pump from air using a specific gravity difference, collects the collected toner, and introduces the collected toner into the developing device. Control means is provided for causing the pump to perform intermittent operation to suppress heat generation of the movable portion during the image forming operation by the image forming apparatus.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on the illustrated examples.
[0013]
(1) Outline of Image Forming Apparatus According to the Present Invention In FIG. 3, this image forming apparatus is an example of a copying machine, and the copying machine main body 10 is exposed to perform image formation by a conventionally known electrophotographic method. The image forming unit 13 includes an image forming unit 13, an image forming unit 13, and a paper feeding unit 14. The exposure unit 20 includes a light source 22 for irradiating the document placed on the contact glass 21 with light, and mirrors 23, 24, 25, 27 for exposing the reflected light image from the document onto the photoconductor 100. , 28 and 29 and an exposure optical system comprising the lens 26.
[0014]
The image forming unit 13 includes a drum-shaped photoconductor 100 and a charging unit 150, a developing unit 200, a registration roller 250, a transfer belt unit 405, a photoconductor cleaning unit 300, a fixing unit 500, and the like disposed around the photoconductor 100. Has been. The paper supply unit 14 is provided with a plurality of paper supply cassettes that accommodate transfer papers of various sizes. If the laser scanning optical system using a laser light source and a deflector is used as the exposure unit 20 and optical writing is performed on the photoconductor in accordance with the image signal, the configuration of the laser printer can be obtained. If the device is installed, it becomes a configuration of a digital copying machine or a facsimile.
[0015]
In FIG. 3, when the image forming operation is started, the photosensitive member 100 is charged by the charging unit 150, and the original image from the exposure unit 20 is exposed to form an electrostatic latent image. This electrostatic latent image is developed with a developer (two-component developer or one-component developer) of the developing unit, and a toner image is formed on the photoreceptor 100. The toner image on the photoconductor 100 is transferred to the transfer paper fed from the paper feed unit 14 and fed to the transfer position (nip portion between the photoconductor and the transfer belt 400) via the registration roller 250, and the toner image. Is transferred to the fixing unit 500 by the transfer belt 400 of the transfer belt unit 405, and the toner image is fixed on the transfer paper by the fixing unit 500.
[0016]
The fixed transfer sheet is discharged onto a discharge tray 600 via a discharge roller 550. On the other hand, the photoconductor 100 after the toner image is transferred is scraped off by the blade of the photoconductor cleaning unit 300 and collected in the lower part of the casing constituting the photoconductor cleaning unit 300. Further, the transfer belt 400 after the transfer paper is conveyed is also cleaned by the transfer belt cleaning unit 410 in the transfer belt unit 405 and collected in the lower part of the casing constituting the transfer belt cleaning unit 410.
[0017]
In the copying machine having the configuration shown in FIG. 3, the photoconductor cleaning unit 300 and the transfer belt cleaning unit 410 in the transfer belt unit 405 are both examples using a blade cleaning method. The developing unit 200 includes a developing unit having a developing roller for developing a latent image on the photoreceptor 100, a stirring paddle for stirring the developer, and the like, and a toner supplying unit for supplying toner to the developing unit. The toner replenishing section is supplied with unused toner from a toner storage means (storage tank or the like) 52 via a transfer path 51.
[0018]
In this example, the photosensitive member cleaning unit 300 and the transfer belt cleaning unit 410 constitute an example of a cleaning unit that cleans and collects residual toner of the image forming apparatus. The toner is transferred to the 200 toner replenishing section 220 (see FIG. 7) for reuse.
[0019]
Since the present invention relates to the collected toner transfer device, the collected toner transfer device will be described. The collected toner of the photosensitive member cleaning unit 300 and the transfer belt cleaning unit 410 is indicated by a two-dot chain arrow in FIG. The path is sent to the collected toner transfer unit 320, and is sent to the toner replenishing unit of the developing unit 200 by following the path indicated by the two-dot chain line arrow by the conveying force of the collected toner transfer unit 320.
[0020]
The flow of the collected toner from the photoconductor cleaning unit 300 and the transfer belt cleaning unit 410 to the collected toner transfer unit 320 will be described with reference to FIGS. The toner collected by the photosensitive member cleaning unit 300 passes through a cylindrical collected toner discharge portion 301 provided in a part of the photosensitive member cleaning unit 300, and is part of the collected toner transfer unit 320 engaged therewith. The toner is transferred to a toner guide member 321.
[0021]
The toner guide member 321 has a cylindrical portion having a length in the vertical direction. The toner guide member 321 is engaged with a collected toner discharge portion 301 provided in a part of the photoreceptor cleaning unit 300 and a collected toner discharge portion 411 provided in a part of the transfer belt cleaning unit 410. Recovered toner discharge members (coil screws and the like) 302 and 412 are built in the recovered toner discharge portions 301 and 411, and the toner recovered by the photoconductor cleaning unit 300 and the transfer belt cleaning device 410 is collected. The toner is transferred to the toner guide member 321. The toner guide member 321 functions as a toner transfer path (during operation) and a collection container (during non-operation) for sending toner from the photoreceptor cleaning unit 300 to the powder pump 330 for transferring collected toner.
[0022]
Similarly, toner collected by the transfer belt cleaning unit 410 of the transfer belt unit 405 is also transferred to a collected toner discharge portion 411 provided in a part of the transfer belt unit 405. Reference numeral 110 in the drawing denotes a main body structure (main body driving rear plate) of the copying machine main body 10, and includes a photoconductor cleaning unit 300, a transfer belt unit 405, a photoconductor 100, a developing device 200, other image forming members, A support member 339 and the like of the collected toner transfer unit 320 are attached.
[0023]
In the example of FIG. 3, an image forming apparatus using the transfer belt 400 is shown. However, instead of the transfer belt 400, a conventionally used corona transfer device or bias roller transfer device may be used. When the apparatus is used, the transfer belt cleaning unit 410 shown in FIGS. 3 and 4 is not necessary. FIG. 6 is a cross-sectional view of the main part showing the structure of the collected toner transfer unit 320.
[0024]
In FIG. 6, a powder pump 330 for transferring collected toner is shown as an example of a so-called commonly known “Mono pump”. This is a screw pump composed of a rotor 331 and a fixed stator 332 which is disposed so as to wrap around the rotor 331 and which has a passage of the rotor and is brought into contact with the rotor. The rotor 331 is substantially coaxially engaged with one end side of the lateral conveying screw 333, and the other end portion of the lateral conveying screw 333 is supported by a bearing 335 fixed to a supporting member 339 via a seal member 334, and the outer side of the hopper 337. Is engaged with the following driven gear 336. A hopper 337 in which the lateral conveying screw 333 is disposed is supported by a support member 339 and engaged with the toner guide member 321 to constitute a recovered toner transfer path to the powder pump 330.
[0025]
The powder pump 330 is attached to a support member 339 by a holder 338 and is connected to a hopper 337. The drive motor 340 is attached to the support member 339, and has a drive gear 341 at the end of the drive shaft. The drive gear 341 is engaged with the driven gear 336 described above. Accordingly, when the drive motor 340 rotates, the lateral conveying screw 333 and the rotor 331 rotate via the drive gear 341 and the driven gear 336, and the collected toner transferred into the hopper 337 via the toner guide member 321 is laterally transmitted. It is transferred to the powder pump 330 by the conveying screw 333.
[0026]
A powder pump (Mono pump) 330 includes a rotor 331 connected to a drive motor 340 via a lateral conveying screw 333, and a fixed stator 332 made of an elastic body such as a rubber material and surrounding the rotor 331. And a holder 338 for holding the stator 332. There is a gap of about 1 mm between the side surface of the stator 332 and the inner side surface of the holder 338, which communicates with the collected toner passage (discharge unit) 350, and the air supply port 351 is blown into the collected toner passage 350 from the gap. Is provided. The air supply port 351 communicates with the collected toner passage 350 on the inner side, and the outer side is connected via an air discharge port 361 and an air supply pipe 362 provided in an air pump 360 as air supply means as shown in FIG. Communicate. The air pump 360 is motivated by the motor 340 and sucks air from a suction pipe 363 provided outside the machine, and blows air into the collected toner through the air supply port 351 at a blowing rate of about 1 liter / minute. As a result, fluidization of the collected toner exiting from the collected toner passage 350 of the powder pump 330 is promoted, and the collected toner transfer by the powder pump 330 is ensured.
[0027]
The toner discharged from the powder pump 330 is sent to a toner collecting device (cyclone system) 230 shown in FIG. 7 through a toner supply pipe 380.
[0028]
The toner collecting device 230 has a unit structure formed separately from the developing unit 200, and collects the collected toner transferred in a mixed state with air from the collected toner transfer unit 320 via the toner supply pipe 380. Collected separately from the air, collected in the toner replenishing section 220 of the developing unit 200, mixed with unused toner, and used for reuse. Further, although not shown, the toner collecting device 230 is also connected to a pipe constituting the transfer path 51 from the toner storage means 52 described above.
[0029]
As shown in FIG. 7, the toner collecting device 230 has a funnel-shaped toner separation unit 230 </ b> A that is installed above the hopper 220 </ b> A of the toner supply unit 220 of the developing unit 200 and has a longitudinal direction set in the longitudinal direction. The toner separation unit 230A separates the toner (collected toner or replenished toner), which has been transferred in a mixed state with air through the collected toner supply pipe 380 and the like, and air, and drops only the toner by gravity. The toner supply unit 220 can be introduced into the hopper 220A. For this reason, one end of the toner supply pipe 380 and the like is connected to the upper position of the toner separation unit 230A, and an opening 230B connected to the hopper 220A of the toner supply unit 220 is formed in the lower position. As a result, when the air / toner mixture sent from the toner supply pipe 380 or the like collides with the inner peripheral wall of the toner separation unit 230A, a spiral motion occurs depending on the shape of the toner separation unit 230A and the discharge position from each pipe. As the air with a low specific gravity rises, only the toner with a large specific gravity falls, so that the air and the toner are separated, and only the toner is collected, and is collected in the hopper 220A of the toner replenishing unit 220. Dropped and collected. Further, the separated air is discharged from a filter 231 provided at the upper part of the toner separation unit 230A. Therefore, the toner and air are reliably separated, and only the toner is supplied to the toner replenishing unit 220 of the developing unit 200.
[0030]
(D) In 請 Motomeko example Figure 1 of the invention described, the drive motor 340 of the powder pump 330 is driven by a drive motor control circuit 340A. The drive motor control circuit 340 </ b> A is driven by a control signal from the CPU 700 as a control unit via the port 390. The air pump 360 is driven by an air pump control circuit 360 </ b> A and driven by a control signal from the CPU 700 via the port 390. Information on the number of copies actually taken is input to the CPU 700 from the copy number counter 401 built in the copying machine main body 10 every moment. Here, the CPU 700 constitutes an example of control means for causing the powder pump 330 to operate intermittently during a copying operation by the copying machine. The content of this intermittent operation is control for operating the powder pump 330 for a set time for each set number of copies, and control for operating the air pump 360 as air supply means in synchronization with the powder pump 330 can be performed. it can.
[0031]
Normally, in a copier, the amount of toner collected from the photoconductor cleaning unit 300 and the transfer belt unit 405 is very small. For example, the maximum amount is 10 g or less per 100 copies, and the capacity of the toner guide member 321 is 50 g. For example, the powder pump pump 330, that is, the drive motor 340 may be driven once every 500 copies.
[0032]
If the maximum discharge amount (discharge capacity) of the powder pump 330 is 30 g / min, the operation time of the drive motor 340 may be 2 minutes. Therefore, if the copying machine is 50 sheets (50 sheets / minute), it can be set to 10 minutes standby, 2 minutes operation (or 5 minutes standby, 1 minute operation). At this time, the operation time is 2 minutes / 12 minutes, that is, 1/6 as compared with the case where the operation of the copying machine main body is synchronized.
[0033]
This example will be described with reference to the flowchart of FIG. When copying is started, the copy number counter 401 counts up from 1 in step S1. If it is determined in step S2 that the count value, that is, the number of copies has reached 500, both the drive motor and the air pump 360 are turned on in step S3. These on states are continued for 2 minutes as shown in step S4, and when this time elapses, they are turned off, that is, stopped. In step S5, the copy number count is cleared.
[0034]
2 is an example in which the powder pump 330 and the air pump 360 are synchronized. Note that this is an example, and the amount of collected toner and the discharge capacity of the powder pump vary depending on each condition, so the setting differs for each machine.
[0035]
As described above, by operating the powder pump 330 intermittently, the operation time can be significantly reduced, and the temperature rise of the powder pump 330 can be minimized. As a result, the occurrence of high temperature blocking of the toner and the deterioration of the fluidity of the toner can be prevented, and the recovered toner can be reliably transferred. Further, since the temperature rise can be suppressed, damage to the collected toner due to thermal stress can be prevented, and it can be sufficiently applied to the reuse of the collected toner. Further, the wear of the stator 330 of the powder pump 330 and the toner sticking of the rotor 331 can be prevented, and the service life of the powder pump can be extended. Furthermore, since the air pump 360 as the air supply means is also intermittently operated, the operation time of the air pump 360 is greatly reduced, and the service life of the air pump 60 can be extended.
[0036]
【The invention's effect】
According to the present invention, toner and air are reliably separated by the toner collecting means, only the toner is transferred to the developing device, and the operation of the powder pump is intermittent, so that the heat generation of the movable part is suppressed. In addition, high-temperature blocking of toner does not occur, and toner fluidity deterioration does not occur, so that the collected toner can be reliably transferred, and the collected toner cannot be reused due to thermal stress, and the powder pump performance deteriorates early. The problem of visiting is resolved.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a control means for intermittent operation according to the present invention.
FIG. 2 is a flowchart illustrating a procedure of intermittent operation in the present invention.
FIG. 3 is a schematic configuration diagram of an image forming apparatus suitable for carrying out the present invention.
FIG. 4 is a perspective view of essential parts of these units, illustrating the relationship between a photosensitive member cleaning unit and a recovered toner transfer unit for transferring toner.
FIG. 5 is a partial cross-sectional view illustrating a conveyance path from a photosensitive member cleaning unit and a transfer belt cleaning unit to a collected toner transfer unit.
FIG. 6 is a cross-sectional view of a main part of a collected toner transfer unit.
FIG. 7 is a cross-sectional view of main parts of a toner collecting device and a developing unit.
[Explanation of symbols]
330 Powder Pump 360 Air Pump

Claims (1)

A recovery toner transfer device provided in the image forming apparatus, the cleaning means for cleaning and recovering the residual toner of the image forming apparatus, and the recovery toner supply for transferring the recovery toner recovered by the cleaning means to the developing device Having means,
The recovered toner supply means includes a powder pump, an air supply means, and a toner collecting device,
The powder pump has a rotor that moves toner in an axial direction by rotating, and a fixed stator that is in contact engagement so as to enclose the rotor,
The air supply means is a recovered toner transfer device for supplying air to fluidize the toner to the powder pump;
The toner collecting device separates the collected toner from the powder pump from air using a specific gravity difference, collects the collected toner, and introduces the collected toner into the developing device.
A recovery toner transfer device comprising: a control means for causing the powder pump to perform an intermittent operation for suppressing heat generation of the movable portion during an image forming operation by the image forming device.

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