JP2003295629A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that reduces running cost by preventing an increase in toner consumption which results from the supply of toner serving as a lubricant agent. <P>SOLUTION: The apparatus comprises: image forming parts Pa, Pb, Pc and Pd which form toner images on corresponding photosensitive drum; photosensitive drum cleaners 4a, 4b, 4c and 4d which remove and recover toners on the corresponding photosensitive drums after the toner images are transferred to a recording material P; a transfer belt 24 which holds and carries the recording material P on the surface thereof; a transfer belt cleaner 8 which removes and recovers the toners sticking to the transfer belt 24; and a toner supply device 5 which supplies the toners onto the transfer belt 24. The toners removed and recovered by the photosensitive drum cleaners 4a, 4b, 4c, and 4d or the transfer belt cleaner 8 are supplied to the transfer belt 24 by the toner supply device 5. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an electrophotographic system and includes a recording material carrier or an intermediate transfer member that carries and conveys a recording material, and a cleaning device that cleans the recording material carrier or the intermediate transfer member. Image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, a plurality of image forming sections using an electrophotographic system are provided, each of the image forming sections forms a toner image of a different color, and the toner images are sequentially superposed on the same recording material. An image forming apparatus that transfers and forms a color image has been proposed. In particular, there has been proposed a color copying machine provided with an endless belt-shaped recording material carrier for high-speed color recording and having a plurality of image forming portions arranged linearly along the belt. In addition, there is also a color copying machine that includes an intermediate transfer member and sequentially transfers the toner images formed by the respective image forming units on the intermediate transfer member, and then collectively transfers the toner images onto a recording material. Proposed.

These devices are equipped with a cleaning device for cleaning the dirt of the toner image adhering to the recording material carrier or the intermediate transfer member. As this cleaning device, a blade made of an elastic material such as rubber that is brought into contact with the surface of the recording material carrier or the intermediate transfer member is often used.

When a cleaning operation is continuously performed for a long time using such a blade, the frictional force between the blade and the recording material carrying member or between the blade and the intermediate transfer member increases, so that the edge of the blade is recorded. In some cases, so-called blade curling occurs, which causes the material carrier or the intermediate transfer member to be reversed along the running direction. Therefore, by regularly supplying the toner onto the recording material carrier or the intermediate transfer member,
Toner as a lubricant is always present between the edge of the blade and the recording material carrier or the intermediate transfer member to prevent an increase in frictional force.

As a method of supplying toner, a photoreceptor is charged and exposed to form an electrostatic latent image, the latent image is developed to form a toner image pattern, and the toner image pattern is formed on a recording material carrier. It is directly transferred onto the surface and is supplied to the cleaning blade of the recording material carrier. Alternatively, the toner image pattern formed on the photoconductor is transferred to the intermediate transfer member, and the toner image pattern is directly supplied to the cleaning blade of the intermediate transfer member without being transferred to the recording material. As described above, in addition to the method of transferring and supplying the toner image pattern to the recording material carrier or the intermediate transfer member, a dedicated toner container is provided,
There is also used a method of applying a toner from the storage container to a recording material carrier or an intermediate transfer member using a toner applying member.

[0006]

However, in the above-mentioned conventional example, the toner is used as a lubricant as described above in addition to forming a toner image on a recording material, so that the toner consumption amount is increased and the running cost is increased. There was a problem of going up. Further, since the amount of waste toner increases and the waste toner accumulates quickly in the waste toner collection container, it is necessary to frequently clean the collection container, which is inconvenient. Further, in the method of applying the toner, when the surface characteristics of the recording material carrier or the intermediate transfer member are changed with time or the environmental humidity is changed, there is a possibility that the applied amount is reduced and blade curling occurs.

An object of the present invention is to supply a toner of a lubricant by eliminating an increase in toner consumption accompanying the supply,
An object of the present invention is to provide an image forming apparatus with reduced running cost.

[0008]

The structure of the present invention for achieving the above object is an image forming means for forming a toner image on an image carrier, and an image carrier after the toner image is transferred to a recording material. A first cleaning means for removing and collecting the upper toner, a recording material carrier for carrying and conveying a recording material on the surface, a second cleaning means for removing and collecting the toner adhering to the recording material carrier, and the recording material carrier. A toner supply unit for supplying toner onto the body, and the toner removed and collected by the first cleaning unit or the second cleaning unit is supplied to the recording material carrier by the toner supply unit. It is characterized by

Alternatively, an image forming means for forming a toner image on the image carrier, an intermediate transfer member carrying the toner image formed on the image carrier, and an image after the toner image is transferred to the intermediate transfer member. A first cleaning unit that removes and collects the toner on the carrier, a second cleaning unit that removes and collects the toner attached to the intermediate transfer member, and a toner supply unit that supplies the toner onto the intermediate transfer member. The toner removed and collected by the first cleaning unit or the second cleaning unit is supplied to the recording material carrier by the toner supply unit.

According to the above construction, the toner collected from the image carrier, the recording material carrier, and the intermediate transfer member is supplied to the recording material carrier or the intermediate transfer member by the toner supply means. It is possible to eliminate unnecessary toner consumption and reduce running costs.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However,
The dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the following embodiments should be appropriately changed depending on the configuration and various conditions of the device to which the present invention is applied, and are particularly specific. Unless otherwise stated, the scope of the present invention is not intended to be limited thereto.

First Embodiment An image forming apparatus according to the first embodiment to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of the image forming apparatus according to the present embodiment.

The photoconductor drums 3a, 3b, 3c and 3d are rotatably movable, and the charging means 2 is provided on the outer circumference thereof.
a, 2b, 2c, 2d, developing means 1a, 1b, 1c, 1
d, transfer charging means 25a, 25b, 25c, 25d, and cleaners 4a, 4b, 4c, 4d, and a light source device and a polygon mirror (not shown) are installed in the upper part of the device.

The photosensitive drums 3a, 3b, 3c, 3d are charged to a predetermined potential by the charging means 2a, 2b, 2c, 2d, and then the laser light emitted from the light source device is scanned by rotating the polygon mirror. , The light flux of the scanning light is deflected by a reflection mirror, and is condensed and exposed on a generatrix of the photoconductor drums 3a, 3b, 3c, 3d by an unillustrated fθ lens to expose the photoconductor drums 3a, 3b, 3c. , 3d, a latent image corresponding to the image signal is formed.

Each of the developing means 1a, 1b, 1c, 1d holds a two-component developer containing carrier particles made of a magnetic material such as iron oxide as a developer, and the carrier particles and cyan, magenta, yellow and A two-component developer containing black toner is filled in a predetermined amount by a supply device (not shown). Developing means 1a, 1b, 1c, 1d
Develops the latent images on the photoconductor drums 3a, 3b, 3c, 3d, respectively, to generate a cyan toner image, a magenta toner image,
Visualize as a yellow toner image and a black toner image.

The recording material P is accommodated in the recording material cassette 21, and is supplied from the recording material cassette 21 to the transfer belt 24 through the transfer path 22 through the transfer rollers 22 and the registration rollers 23, and is transferred by the transfer belt 24 to be transferred to the photosensitive member. Drum 3
It is sequentially sent to the transfer portion facing a, 3b, 3c and 3d.

The transfer belt 24 is made of a dielectric resin sheet of polyimide, polyethylene terephthalate (PET), polyvinylidene fluoride, polyurethane, etc., and both ends thereof are superposed and joined to each other to form an endless shape, or A seamless (seamless) belt is used. The volume resistance of such a transfer belt is generally 10 ¹³ to 10 ¹⁸ Ωcm.
In this embodiment, a polyimide resin sheet is used.

Now, the driving roller 26 and the tension roller 27
The transfer belt 24 supported by is rotated by the drive of the drive roller 26, and when it is confirmed that the transfer belt 24 is in a predetermined position,
The recording material P is sent from the registration roller 23 to the transfer belt 24, and the recording material P is conveyed toward the transfer portion of the first image forming portion Pa. At the same time, the image writing signal is turned on, and the image is formed on the photosensitive drum 3a of the first image forming portion Pa at a certain timing with reference to the signal. Then, the transfer charging unit 25a applies an electric field or an electric charge at a transfer portion below the photoconductor drum 3a, so that the first color toner image formed on the photoconductor drum 3a is recorded on the recording material P.
Transcribed on. By this transfer, the recording material P is firmly held on the transfer belt 24 by the electrostatic attraction force, and is conveyed to the second image forming portion Pb and thereafter.

Similarly, as the transfer charging means 25, a non-contact charging means such as corona discharge or a contact charging means using a transfer charging member such as a blade, a roller or a brush is used. The contact charging means has an advantage that the amount of ozone generated is small. In this apparatus, a blade which is a contact charging means and which can obtain high image quality is used. It is known that the transfer charging unit 25 stabilizes the image when the current contributing at the time of transfer is kept constant at an appropriate current. Therefore, it is common to perform constant current control so that a constant current can be obtained even when the volume resistance value changes depending on the type of recording material (thickness, material, etc.), moisture absorption conditions, and the like.

Image formation and transfer in the second to fourth image forming portions Pb, Pc and Pd are performed in the same manner as in the first image forming portion Pa. Next, the recording material P on which the four color toner images have been transferred is
At the downstream portion of the transfer belt 24 in the conveying direction, the charge is removed by the separation charging unit 28 to attenuate the electrostatic attraction force, and the transfer belt 24 is separated from the end.

The released recording material P is supported by the guide member 29, and is further conveyed to the fixing device 31 by the conveying portion 30 and fixed. Recording material P on which toner images of four colors have been transferred
The toner image is mixed and fixed on the recording material P by fixing, and is formed into a full-color copy image, and is discharged to the discharge tray 32.

After the transfer, the photosensitive drums 3a, 3b,
3c and 3d are photosensitive drum cleaners 4a, 4b and 4
The residual toner after transfer is cleaned and removed by c and 4d (first cleaning means), and the preparation for the subsequent latent image formation is prepared. Toner and other stains remaining on the transfer belt 24 are removed by a blade 8a made of urethane rubber that is in contact with the transfer belt 24, and collected by a transfer belt cleaner 8 (second cleaning means).

Next, the toner supply device according to this embodiment will be described. Reference numeral 5 in FIG. 1 denotes a toner supply device that supplies toner to the transfer belt 24, and is arranged upstream of the blade 8a in the traveling direction of the transfer belt 24. The toner supply device 5 is connected to a conveying pipe 6 (dotted line in FIG. 1), and the conveying pipe 6 is connected to the photosensitive drum cleaners 4a, 4b, 4.
The residual toner collected in c and 4d is collected and conveyed to the toner supply device 5.

Next, the structure of the toner supply device 5 will be described with reference to FIG. Inside the toner supply device 5, there is provided a toner carrying roller 50 (toner carrying body) which is composed of a fixed magnet roller 5b and a sleeve 5a which is coaxial with the magnet roller 5b and is made of a metal pipe such as stainless steel or aluminum. The toner carrying roller 5 is provided.
An agitating blade 5c is arranged in the adjacent portion of 0.

The residual toner T is sent from the photosensitive drum cleaners 4a, 4b, 4c, 4d to the toner supply device 5 by the carrying pipe 6 and the carrying screw 6a provided in the carrying pipe 6. Inside the toner supply device 5, the developing means 1 is previously provided.
The carrier particles C, which are the same as the carrier particles filled in a, 1b, 1c, and 1d, are filled in a predetermined amount, and the residual toner T and the carrier particles C are sufficiently mixed and stirred by the stirring blade 5c. When the carrier particles C are brought into contact with the toner T and agitated, the carrier particles C have a function of giving an electric charge to the toner T and charging the toner (toner charging means). Usually, the residual toner includes toner that has a smaller charge amount than the average charge amount and is left on the photosensitive drum without being transferred. Further, the collected residual toner has no opportunity to come into contact with the carrier particles, so that the charge amount gradually decreases and decreases. Therefore, the charge amount of the residual toner T is low. Even when the residual toner is physically applied to the transfer belt in this way, the electrostatic adhesion force is weak due to the small charge amount, and the residual toner may not be sufficiently adhered. Further, in a high humidity environment, the charge amount may be further reduced, and the adhesion amount may be further reduced.

In this embodiment, the charge amount of the residual toner T could be increased by stirring the residual toner T with the carrier particles C. The agitated residual toner is electrostatically adhered to the carrier particles, becomes integral with the carrier particles, and is sent to the surface of the toner carrying roller 50 by the rotation of the agitating blade 5c. Since the toner carrying roller 50 includes the magnet roller 5b, the carrier particles to which the residual toner is attached are magnetically adsorbed on the toner carrying roller 50 and the sleeve 5 is attached.
By the rotation of a, it is carried to a portion facing the transfer belt. The sleeve 5 a is arranged with a minute distance so that the residual toner and carrier particles applied to the surface of the sleeve 5 a do not contact the transfer belt 24. Therefore, the recording material carried on the transfer belt is not soiled and the toner image on the recording material is not disturbed.

A power source 5d is connected to the sleeve 5a, while a grounded electrode plate 7 is placed on the rear surface of the transfer belt at the facing portion. A predetermined bias is applied from the power source 5d to the sleeve 5a so that only the residual toner carried to the facing portion is electrically attracted to the electrode plate 7 to fly and adhere to the transfer belt. In the case of the present embodiment, a negatively chargeable toner is used, and in order to adhere only this negatively charged toner to the transfer belt, a bias in which an AC voltage is superimposed on the DC voltage of the positive electrode is used. Superimposing an AC voltage had the effect of increasing the amount of adhesion. A rectangular wave having a frequency of 2 kHz and a Vpp of 1 kV was used as the DC voltage of -500 V and the AC voltage. As a result, 0.5 mg / cm ² of toner was attached to the transfer belt. Further, the control of the supply time per time is performed by turning on / off the rotation of the sleeve 5a or turning on / off the bias, and as the adhesion width per time,
The width of the transfer belt in the running direction is 5 mm, and the width in the direction perpendicular to the running direction is 300 mm, which is almost equal to the width of the blade 8a.
Set to. Regarding the supply interval, the supply was performed once for every 100 sheets of image formed.

By thus supplying the residual toner to the blade 8a, it is possible to prevent the blade from curling. In addition, since the residual toner is used as the supply toner,
It was possible to avoid consumption of new toner and reduce running costs. Further, even though the residual toner whose charge amount has decreased is used, the charge amount is increased by the recharging means of the residual toner and is supplied to the transfer belt by using the electric force, so that the supply amount is stable. Could be maintained.

[Second Embodiment] In the first embodiment, the carrier particles are used to recharge the residual toner, but in addition to this, the residual toner may be charged using a corona discharge means or the like. FIG. 3 shows a schematic configuration of the image forming apparatus according to the second embodiment. In FIG. 3, components having the same functions as those in FIG. 1 are given the same numbers as in FIG. Also, since the functions are the same, the description is omitted.

Photoreceptor drum cleaners 4a, 4b, 4c,
The residual toner collected in 4d is sent to the toner supply device 10 through the conveying pipe 16. The toner supply device 10 includes a brush roller 11 in which conductive brushes are implanted on a metal roller.
(Toner carrier), and the brush roller 11 has a power source 1
The bias is applied by 2. Brush roller 11
Contacts the transfer belt 24 and rotates in the driven direction with respect to the running direction of the transfer belt. Brush roller 11
Since the recording material has been removed from the transfer belt portion facing to, there is no problem of soiling the recording material even if the brush roller 11 is brought into contact with the transfer belt. Further, around the brush roller 11, the corona discharge means 13 facing the brush roller 11 is provided.
(Toner charging means) is provided, and the corona discharge means generates negative corona discharge by the negative high voltage supplied from the DC high voltage power supply 14. The residual toner sent to the toner supply device 10 adheres to the brush roller 11 and is sent to the surface of the transfer belt by the rotation of the brush roller 11.
At this time, the residual toner undergoes corona discharge by the corona discharge means 13 on the way to the surface of the transfer belt, and the amount of charge is increased. As a result, the sufficiently charged residual toner was made to adhere to the transfer belt by the electric field generated between the biased brush roller 11 and the grounded electrode plate 15 at the contact portion with the transfer belt.

As described above, even when the corona discharge means was used as a method of recharging the residual toner, the residual toner was sufficiently charged and the residual toner could be stably supplied to the transfer belt.

[Third Embodiment] In the above embodiment, an example in which the present invention is applied to an apparatus using a transfer belt as a recording material carrying member has been described. However, an intermediate transfer member is used in addition to the transfer belt. It may be applied to the device. FIG. 4 shows a schematic configuration of the image forming apparatus according to the third embodiment. 4, constituent elements having the same functions as in FIG. 1 are given the same numbers as in FIG. Also, since the functions are the same, the description is omitted.

The intermediate transfer member 51 is an endless belt member made of polyimide resin or the like, like the transfer belt, and rotates in the direction of the arrow in the figure. Each photoconductor drum 3a, 3b, 3
The toner images of four colors formed on c and 3d are sequentially transferred onto the intermediate transfer body 51 by the primary transfer charging means 25a, 25b, 25c and 25d, and then transferred to the secondary transfer body by the rotation of the intermediate transfer body 51. It is carried to the transfer position 52. The recording material P conveyed from the recording material cassette 21 is sent to the secondary transfer position in synchronism with the movement of the toner image on the intermediate transfer body, and the toner image is brought into contact with the recording material P, and at the same time, the secondary transfer charging is performed. A transfer bias is applied to the means 53 to transfer the toner image onto the recording material. As the secondary transfer charging means 53, a transfer roller made of conductive or semiconductive rubber was used. The recording material, which has been transferred, is fixed via the conveyance unit 30 and the fixing device 31.

In this structure, the cleaning blade 9a is in contact with the intermediate transfer body 51 in order to remove the transfer residual toner remaining on the intermediate transfer body 51 after the secondary transfer. The transfer residual toner removed by the cleaning blade 9a is collected by the intermediate transfer member cleaner 9 (second cleaning means).

In this apparatus, in order to prevent the cleaning blade 9a from curling, the residual toner is supplied to the intermediate transfer member 51. Therefore, the toner supply device 10 is arranged around the intermediate transfer body 51. The configuration and functions of the toner supply device 10 are the same as those in the second embodiment, and will not be described. Further, in this apparatus, not only the residual toner from the photoconductor drum cleaners 4a, 4b, 4c, 4d, but also the residual toner accumulated in the intermediate transfer body cleaner 9 is sent to the toner supply device 10 through the conveying pipe 16. .

As a result, not only the residual toner on the photosensitive drum but also the residual toner on the intermediate transfer member can be utilized, and the residual toner once supplied to the intermediate transfer member from the toner supply device 10 is transferred to the intermediate transfer member cleaner. Since the toner is recirculated to the toner supply device 10 from 9, the residual toner can be effectively used.

[Other Embodiments] In the above-described first and second embodiments, after transfer, the photosensitive drums 3a, 3b, 3c,
A device for supplying the toner collected from 3d by the photoconductor drum cleaners 4a, 4b, 4c, 4d as the first cleaning means to the transfer belt 24 as the recording material carrier using the toner supply device 5 or 10 has been exemplified. However, the present invention is not limited to this. For example, the toner collected from the transfer belt 24 by the transfer belt cleaner 8 as the second cleaning means, or the photosensitive drum cleaner 4 as the first cleaning means.
The toner collected by a, 4b, 4c, 4d and the transfer belt cleaner 8 as the second cleaning means may be supplied to the transfer belt 24 using the toner supply device 5.

Further, in the above-described third embodiment, the photosensitive drum cleaners 4a, 4 as the first cleaning means.
toner collected by b, 4c, and 4d, and the second
Although the toner supply device 10 supplies the toner collected by the intermediate transfer member cleaner 9 to the intermediate transfer member 51 as an example, the present invention is not limited to this. For example, the first cleaning unit may be used. The toner collected by the photosensitive drum cleaners 4a, 4b, 4c, 4d as the toner or the toner collected by the intermediate transfer body cleaner 9 as the second cleaning unit is supplied to the intermediate transfer body 51 by using the toner supply device 10. It may be done.

In the above-described embodiment, the image forming apparatus having four image forming units for forming toner images on the photosensitive drum has been described as an example. However, the present invention depends on the number of image forming units. Instead, it is effective regardless of the number of image forming units.

[0040]

As described above, according to the present invention,
As the toner to be supplied to the recording material carrier or the intermediate transfer member,
Since the toner collected from the image bearing member, the recording material bearing member and the intermediate transfer member is used, unnecessary toner consumption can be eliminated and running cost can be reduced.

Further, since the charging means for charging the collected toner is provided and the toner is made to adhere to the recording material carrying member or the intermediate transfer member by the electric force, it is always supplied even if the characteristics of the toner change. The amount can be kept stable.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of an image forming apparatus according to a first embodiment.

FIG. 2 is an explanatory view of main parts showing a schematic configuration of a residual toner supply device.

FIG. 3 is an explanatory diagram showing a schematic configuration of an image forming apparatus according to a second embodiment.

FIG. 4 is an explanatory diagram showing a schematic configuration of an image forming apparatus according to a third embodiment.

[Explanation of symbols]

C ... Carrier particles P ... Recording material Pa, Pb, Pc, Pd ... Image forming unit T: residual toner 1a, 1b, 1c, 1d ... Developing means 2a, 2b, 2c, 2d ... Charging means 3a, 3b, 3c, 3d ... Photosensitive drum 4a, 4b, 4c, 4d ... Photosensitive drum cleaner 5 ... Toner supply device 5a ... Sleeve 5b ... Magnet roller 5c ... Stirring feather 5d ... Power supply 6 ... Conveyor tube 6a ... Conveyor screw 7 ... Electrode plate 8 ... Transfer belt cleaner 8a ... Blade 9 ... Intermediate transfer body cleaner 9a ... Cleaning blade 10 Toner supply device 11 ... Brush roller 12 ... Power supply 13 ... Corona discharge means 14 ... DC high voltage power supply 15 ... Electrode plate 16 ... Carrier tube 21 ... Recording material cassette 22 ... Transport path 23 ... Registration roller 24 ... Transfer belt 25a, 25b, 25c, 25d ... Transfer charging means 26 ... Drive roller 27 ... tension roller 28 ... Separate charging means 29 ... Guide member 30 ... Transport section 31 ... Fixing device 32 ... Ejection tray 50 ... Toner carrying roller 51 ... Intermediate transfer member 52 ... Transfer position 53 ... Transfer charging means

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Claims (4)

[Claims] 1. An image forming unit for forming a toner image on an image carrier, a first cleaning unit for removing and collecting the toner on the image carrier after transferring the toner image to a recording medium, and a surface of the recording medium. A recording material carrier that carries and conveys the toner onto the recording material, and a second member that removes and collects the toner adhering to the recording material carrier
Cleaning means and toner supply means for supplying toner onto the recording material carrier, and the toner removed and collected by the first cleaning means or the second cleaning means carries the recording material by the toner supply means. An image forming apparatus configured to be supplied to a body. 2. An image forming unit for forming a toner image on an image carrier, an intermediate transfer member carrying the toner image formed on the image carrier, and an image after the toner image is transferred to the intermediate transfer member. A first cleaning unit that removes and collects the toner on the carrier; a second cleaning unit that removes and collects the toner attached to the intermediate transfer member; and a toner supply unit that supplies the toner onto the intermediate transfer member. An image forming apparatus, wherein the toner removed and collected by the first cleaning unit or the second cleaning unit is supplied to the recording material carrier by the toner supply unit. 3. The toner supply unit includes a toner charging unit that charges the collected toner, a toner carrier that carries the charged toner, and a power supply that applies a bias to the toner carrier. The image forming apparatus according to claim 1, wherein: 4. The first cleaning means and the second cleaning means.
4. The image forming apparatus according to claim 1, wherein the toner removed and collected by the cleaning unit is configured to be supplied to the recording material carrying member by the toner supply unit.