JPH0481785A - Cleaner - Google Patents

Abstract

PURPOSE:To place toner in a uniformly and electrostatically charged state and to improve the cleaning ability of a cleaning means by providing an electrostatic charging means which electrostatically charges toner sticking on a transfer body. CONSTITUTION:The cleaner is provided with the cleaning means 50 which cleans toner on the transfer body 30 through electrostatic operation and electrostatic charging means 39 and 40 which charge the toner on the transfer body 30 electrostatically prior to the cleaning. Thus, when the toner which sticks on the transfer body 30 is charged electrostatically by the electrostatic charging means 39 and 40 to perform the cleaning operation by utilizing the electrostatic operation, the toner can securely be removed and sufficient cleaning effect is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaner for removing toner adhering to the surface of a transfer drum, a transfer belt, etc. provided in a full-color copying machine, for example.

Conventional Kigai full-color copying machines, etc., transfer the visible images of each color of toner formed on a photoreceptor drum onto the same transfer paper in a layered manner to obtain -1 copy. Are known. In this type of copying machine, the transfer paper is held on a transfer drum provided opposite to the photoreceptor drum, and multiple transfers are performed on the transfer paper. The transfer paper on which the overlapping transfer has been completed is peeled off from the transfer drum by the action of a static elimination charger, a separation charger, etc., and sent to a heat fixing process.

By the way, toner and the like that are scattered when the transfer paper is peeled off may adhere to the transfer drum, which may cause staining of the base of the transfer paper that is later held.

Therefore, in order to prevent such problems from occurring, a cleaner is installed.

As such a cleaner, the applicant of the present application has disclosed a patent application filed in 1983-
No. 191100 proposes a method that utilizes electrostatic action. This cleaner electrostatically attracts toner to a conductive brush roller that faces the rotation range of the transfer drum and is applied with a bias voltage of opposite polarity to that of the toner. It is collected by a collection roller to which a potential bias voltage is applied. In order to make this cleaning effect more effective, a static eliminating brush or the like is provided inside the transfer drum as a member facing the brush roller.

However, when cleaning is performed using electrostatic action as described above, although charged toner can be reliably removed, the cleaning effect is not sufficient for uncharged toner. Sometimes I can't get it.

In particular, the toner adhering to the transfer drum includes toner whose charge has decreased due to the effects of the static elimination charger or separation charger, and toner that has been scattered in an uncharged state or a charged state of opposite polarity. Because of the large variation in the amount of toner, some toner may not be reliably removed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cleaner that can reliably clean toner adhering to an object to be cleaned, such as a transfer tram installed in a full-color copying machine, etc., with a simple configuration. shall be.

In order to achieve the above object, the present invention uses a cleaner that cleans toner attached to a transfer member that transfers toner from a photoreceptor to a recording medium to be held, and uses an electrostatic method to remove toner on the transfer member. The present invention is characterized in that it includes a cleaning means that performs cleaning with an effective action, and a charging means that charges the toner on the transfer member prior to the cleaning.

Further, in a cleaner for cleaning toner attached to an intermediate transfer body that further transfers toner transferred from a photoreceptor to a transfer target, a cleaning means for cleaning toner on the intermediate transfer body with an electrostatic action; The apparatus is characterized in that it includes a charging means for charging the toner on the intermediate transfer member prior to cleaning.

According to the above configuration, the charging means charges the toner adhering to the transfer member or the intermediate transfer member, and the cleaning means cleans the charged toner using an electrostatic action.

First Example (1) Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. FIG. 1 is a sectional front view showing the overall configuration of a full-color copying machine to which the cleaner according to the present invention is applied, FIG. 2 is a sectional front view showing the structure around the cleaner section, and FIG. 3 is a sectional front view showing the configuration of the control device. FIG. 4 is a timing chart showing the control operation, and FIG. 5 is a sectional front view showing the state of charge on the transfer drum.

(Overall Configuration of Full-Color Copying Machine) First, the schematic configuration of a full-color copying machine will be described based on FIG.

An image reading unit 26 provided at the top of the copying machine uses light emitted from an exposure lamp 2 and reflected by a document placed on a document glass 1 to pass through a SELFOC lens array 3 to a CCD line sensor 4. The document image is read by exposing it to light. CCD line sensor 4
are B (blue) and G (green) by the above exposure.
, R (red), and these B, G
, R color signals are subjected to image processing to produce Y (yellow), M
(magenta), C (cyan), or B
The signal is supplied to the laser optical system 5 as a color signal of four colors including K (black).

The laser optical system 5 includes a scanning polygon mirror 6, an Fθ lens 7, a reflection mirror 8, etc., and includes the Y, M, C, or Y,
Image forming laser light for each color is irradiated onto the photosensitive drum 9 based on M, C, and BK color signals, thereby exposing the photosensitive drum 9 to light.

The photosensitive drum 9 is formed by laminating an organic photoreceptor consisting of a charge forming layer and a charge transport layer on the surface of a drum made of a conductive substrate, and exhibits high sensitivity at a laser emission wavelength of 780 nm. It is used. The photosensitive drum 9 is driven by a main motor (not shown) to rotate in the direction indicated by an arrow in the figure, and is negatively charged by a main charger 10 disposed around the photosensitive drum 9 prior to the exposure.

On the left side of the photosensitive drum 9, first, second, third
, fourth developing units 11 to 14 are arranged. The developing units 11 to 14 each contain negatively charged yellow toner, magenta toner, and cyan toner.
It accommodates black toner and forms toner images of each color on the photosensitive drum 9. Here, the developing devices 11 to 14 are selectively operated at predetermined timings, and when one of the developing devices is in an operating state, the other developing devices are in a non-developing state, and the developing device in an operating state is in a non-developing state. It is designed not to disturb the formed toner image.

The image forming system using this full color copying machine is N-
P (negative-positive) type, and in the photosensitive drum 9,
By attaching negatively charged toner to the area that has been negatively charged and then exposed to laser light to remove static electricity,
A toner image is formed.

A hopper 15 is provided above each of the developing devices 11 to 14 to supply toner of each color to the developing devices 11 to 14 based on a predetermined toner replenishment signal.

On the other hand, a paper feed cassette 17 installed at the lower right side of the full-color copying machine body stores transfer paper 21 made of plain paper, OHP film, etc. in a stacked state, and is held together by paper feed rollers 18, 18, etc. The sheets are fed into the device one by one. When the leading edge of the fed transfer paper 21 comes into contact with the registration roller 19, it is registered, forming a loop, and skew correction is performed. The amount of the loop formed is appropriately controlled based on the detection signal of the paper feed sensor 20.

In front of the registration rollers 19, a transfer drum 30 is provided which is driven by a main motor and rotates in the direction indicated by an arrow in the figure. The transfer drum 30 has a drum frame made of aluminum, a dielectric film with a thickness of 70 to 120 μm,
Alternatively, the drum surface is made of polyester film.

The frame 36 that supports the transfer drum 30 is rotatably supported around a fulcrum 37, and is biased by a pressure spring 38 in a rotation direction approaching the photosensitive drum 9, while being biased by a positioning roller 35 to rotate the amount of rotation. is regulated, and the distance between the transfer drum 30 and the photosensitive drum 9 is 0.3 mm.
It is designed to be maintained at about 0.7 mm.

The transfer drum 30 has a tip chuck claw 3 that chucks the tip of the transfer paper 21 fed from the registration roller 19.
1 is provided, and after this tip chuck claw 31 chucks the transfer paper 21, an adsorption charger 32 provided inside the transfer drum 30 negatively charges the inner surface of the drum, and a counter electrode 33 provided externally charges the transfer paper 21. The surface of the transfer paper 21 is electrically grounded by contacting the paper 21, and the transfer paper 2
1 is electrostatically attracted to the transfer drum 30.

The toner images of each color formed on the photosensitive drum 9 by the developing devices 11 to 14 are sequentially superimposed on the attracted transfer paper 21 by a transfer charger 34 for positive charging provided inside the transfer drum 30, and are electrostatically charged. It is meant to be transcribed. The transfer charger 34 also functions as a charging means for charging the toner attached to the transfer drum 30, as will be described later.

The transfer paper 21 on which the toner images of all colors have been transferred is removed by first and second charge-eliminating chargers 39 and 40 provided outside the transfer drum 30, which remove electricity from the drum surface, and separate the drum surface (not shown). The cam separates the tip chuck claw 31 from the transfer drum 30 by placing it in a non-chucking state. The peeled transfer paper 21 is fed to a fixing block 43 by a suction conveyance unit 42 via a separation claw 41, and after heat roll fixing is performed, it is ejected to a paper ejection tray 45 by a paper ejection roller 44 to make a full color copy. will be obtained.

Note that the static elimination chargers 39 and 40 are both used to eliminate static electricity using AC output, and the static elimination charger 39 mainly eliminates the electrostatic attraction force between the drum surface and the transfer paper 21, while the static elimination charger 40 mainly eliminates the electrostatic adhesion between the drum surface and the transfer paper 21. At the time of separation, the surface of the transfer paper 210 is neutralized, and discharge accompanying the separation is prevented, thereby preventing the image from scattering.

(Details of Cleaner Section) Next, the configuration of the cleaner section will be explained based on FIG. 2. As shown in FIG. 1, the cleaner section 50 is provided on the downstream side of the transfer process, that is, below the separation claw 41 and the suction conveyance section 42. The cleaner section 50 includes a conductive brush that slides into contact with the drum surface of the transfer drum 30 by driving a brush roller pressure contact solenoid (not shown) after the transfer process, scrapes off toner adhering to the drum surface, and electrostatically deposits the toner. A roller 51, a collection roller 52 that adsorbs and collects toner from the brush roller 51, a scraper 53 that scrapes off the toner that has been adsorbed and collected from the peripheral surface of the collection roller 52, and a drum surface sandwiched within the transfer drum 30. A back electrode 54 is arranged opposite to the brush roller 51 so as to reduce electric charge on the back side of the drum surface.
are provided.

To explain in more detail, the brush roller 51 is biased to a potential 1 having the opposite polarity (positive polarity) to the toner attached to the transfer drum 30, and the collection roller 52 is biased to a potential V2 higher than that of the brush roller 51. It has been stamped. In this way, the toner scraped from the drum surface by the brush roller 51 and electrostatically attracted thereto is adsorbed and collected by the collection roller 52 having a higher potential at the contact area between the brush roller 51 and the collection roller 52. ing.

The back electrode 54 is connected to the grounded metal base 5 as shown in the figure.
Conductive fibers 56 are implanted at the tip of the brush roller 5 (on the right side in the figure) to increase the electrostatic adsorption ability of the brush roller 51. This back electrode 54 is reciprocated in the left and right direction by a back electrode moving means (not shown), and comes into contact with the inner surface of the transfer drum 30 only during cleaning, while at other times it is retracted inside the drum and distorts the drum surface. This prevents the occurrence of image noise caused by such factors.

Here, instead of being grounded as described above, the back electrode 54 may be biased to a negative potential in order to further enhance the cleaning effect. Also,
The back electrode 54 may be made of an electrode plate instead of having conductive fibers 56 flocked thereon.

(Configuration of Control Device) The operation of each part of the full color copying machine is controlled by a microcomputer 200 shown in FIG. The microcomputer 200 is configured to receive a start signal from a copy start switch (not shown) and signals from sensors provided in various parts. Further, from the microcomputer 200, a main motor, a main charger IO1 adsorption charger 32, a transfer charger 34, a static elimination charger 39
40, operating signals for the brush roller pressure contact solenoid and back electrode moving means, bias voltage application signals to the cleaner section 50, control signals to other parts, etc. are output.

(Control Operation by Control Device) Next, the control operation performed when a copying operation is performed will be explained based on the timing chart shown in FIG. 4.

When the copy start switch is operated and the start signal is turned ON, the microcomputer 200 first operates the main motor. In addition, the image reading unit 26 is operated to read the original image, and the main charger 10 and the laser optical system 5 are operated to expose the photosensitive drum 9 for each color of yellow, magenta, cyan, and black, and the developing unit Developing steps 11 to 14 are carried out sequentially.

On the other hand, the leading edge of the transfer paper 21 fed from the paper feeding force center 17 via the registration roller 19 is chucked by the tip chuck claw 31 of the transfer drum 30, and the suction charger 32 is operated to transfer the transfer paper 21 to the transfer drum. 30 to adsorb it.

Next, the developed toner images of each color are transferred to a transfer charger 34.
The transfer charger 34 is activated each time the toner image passes near the transfer paper 21, and the toner images of each color are transferred onto the transfer paper 21 in an overlapping manner.

Then, when the last color toner image is transferred and the leading edge of the transfer paper 21 reaches the position of the static elimination chargers 39 and 40,
The chuck claw 31 at the tip of the transfer drum 30 is released and the chargers 39 and 40 are activated to remove the transfer paper 21.
is peeled off from the transfer drum 30. Peeled transfer paper 21
is sent to the fixing block 43 by the suction conveyance section 42, where it is thermally fixed.

When the separation of the transfer paper 21 is completed, the static elimination charger 3
9 and 40 are made inactive, and the transfer drum 30 is cleaned.

First, in order to negatively charge the toner adhering to the transfer drum 30, the transfer charger 34 is operated again. Then, as shown in FIG. 5, the inner surface of the transfer drum 30 becomes positively charged, while the toner adhering to the outer surface becomes negatively charged. Here, the transfer charger 34 may be allowed to maintain its operating state after transferring the black toner image, but by first stopping its operation, the static elimination chargers 39 and 40 can be operated. The impact of

On the other hand, a bias voltage is applied to the brush roller 51 and the collection roller 52 of the cleaner section 50, and the brush roller pressure contact solenoid and the back electrode moving means are operated to move the brush roller 51 and the back electrode 54 of the transfer drum 30, respectively. Pressure-contacts the outer and inner surfaces. Here, by applying the bias voltage before operating the brush roller pressure contact solenoid, etc., good leaning can be performed immediately after pressure contact with the transfer drum 30.

Therefore, the positive charge on the inner surface of the transfer drum 30 is
4, the negatively charged toner is removed from the transfer drum 30 reliably because its adsorption force to the transfer drum 30 is reduced, while its adsorption force to the brush roller 51 acts.

When cleaning of the lower transfer ram 30 is completed, the pressure contact of the brush roller 51 and the back electrode 54 to the transfer drum 30 is released, the brush roller 51 is separated from the transfer drum SO, and then the brush roller 51 and the collection roller 52 are moved. Stop applying the bias voltage.

Further, when the cleaned portion of the transfer drum 30 reaches the position of the static elimination chargers 39 and 40, the static elimination chargers 39 and 40 are operated again to remove the static electricity from the transfer drum 30.
Eliminates the zero charge and prepares for the next copying operation.

Next, the cleaner according to the present invention was applied to a monochrome copying machine equipped with a transfer belt 63 instead of the transfer drum 30 and one developer 16 instead of the four developers 11 to 14. An example will be explained in which this is applied.

FIG. 6 is a sectional front view showing the structure of the photosensitive drum 9 and the vicinity of the transfer belt 63. Note that members having the same functions as those in the first embodiment are given the same numbers and their explanations will be omitted.

A pair of rollers 61 and 62 are provided below the photosensitive drum 9, and an endless transfer belt 63 made of dielectric or semiconductor is passed around these rollers 61 and 62.

The transfer heald 63 transports the transfer paper 64 supplied via the registration rollers 19, and also transports the photosensitive drum 9.
It seems to be forced on. The transfer charger 34 is activated while the transfer paper 64 is passing between the photosensitive drum 9 and the transfer belt 63, and transfers the toner image on the photosensitive drum 9 onto the transfer paper 64, and the transfer paper 64 is Even after passing, the transfer belt 63 continues to maintain the open operating state in which it moves one round or more. Therefore, the toner adhering to the transfer heald 63 becomes negatively charged, and the cleaner section 50 reliably performs cleaning by electrostatic action.

Next, the toner image of each color is directly transferred onto the intermediate transfer belt 76 in an overlapping manner, and then transferred all at once onto the transfer paper 85 according to the present invention. An example in which a cleaner is applied will be explained.

FIG. 7 is a cross-sectional front view showing the structure around the photosensitive drum 9 and the intermediate transfer belt 76. As shown in FIG. Note that members having the same functions as those in the first embodiment are given the same numbers and their explanations will be omitted.

To the right of the photosensitive drum 9 are developing devices 11 arranged vertically.
~14 are provided. These developing devices 11 to 14 are driven by a driving means (not shown) and move up and down integrally, so that each of the developing devices 11 to 14 sequentially faces the photosensitive drum 9 and performs development. .

Five rollers 71 to 75 are provided below the photosensitive drum 9, and an endless intermediate transfer heald 76 made of dielectric or semiconductor and having a smooth outer circumferential side is hooked onto these rollers 71 to 75. has been done.

A first transfer charger 81 is located between the rollers 71 and 72.
is provided. Further, a second transfer charger 82 and a separation charger 83 are provided near the bottom of the rollers 74 and 75. A back electrode 54 and a cleaner section 50 are arranged opposite to each other on the inner and outer peripheral sides of the intermediate transfer belt 76 between the rollers 75 and 71. Further, a charger 8 is provided between the back electrode 54 and the roller 75.
4 are provided.

In the above configuration, the toner images of each color formed on the photosensitive drum 9 are transferred onto the intermediate transfer belt 76 by the first transfer charger 81 in an overlapping manner and are combined.

On the other hand, the end of the transfer paper 85 is connected to the intermediate transfer belt 7.
The toner image is supplied through the registration roller 19 so as to coincide with the edge of the toner image synthesized on the second
The images are transferred all at once onto a transfer paper 85 by a transfer charger 82 . Thereafter, the transfer paper 85 is peeled off from the intermediate transfer heald 76 by the action of the separation charger 83 and sent to the fixing block 43 by the suction conveyance section 42 .

Further, after the above-mentioned transfer is performed, the toner remaining on the intermediate transfer heald 76 or the toner that has been scattered and attached is charged to a negative state by the charger 84. Therefore, the cleaning section 50 reliably performs cleaning by electrostatic action.

In addition, in the first to third embodiments described above, the cleaner section 5
0, an example in which a brush roller and a collection roller are provided has been described, but the present invention is not limited to this. A similar effect can be obtained if cleaning is performed by electrostatic action, such as one equipped with a brush that collects toner by frictional charging between the brushes.

Further, although examples have been shown in which the transfer body such as the transfer drum or the intermediate transfer body is made of a dielectric material such as a film, polyester, or a semiconductor, the present invention is not limited thereto.

Furthermore, by using the transfer charger 34 as the toner charging means as shown in the first and second embodiments, the number of parts can be reduced, the configuration can be simplified, and manufacturing costs can be reduced. However, the present invention is not limited to this, and a dedicated charger, high voltage transformer, etc. may be provided. Further, the form of the charging means is not limited to a charger, but may also be a bias roller, for example, and the arrangement of the charging means is not limited to the inner circumferential side of the transfer body or intermediate transfer body, but may also be provided on the outer circumferential side. . In other words, the toner adhering to the transfer body or intermediate transfer body is
If the device is to be charged to the opposite polarity to the brush roller, etc. in the cleaner section by direct charge injection or indirect charging action via a dielectric material, etc., the shape and material of the transfer body, etc., and the arrangement of peripheral devices should be considered. It can be set arbitrarily depending on the situation.

Further, the cleaning operation of the transfer body etc. may be performed not only after the toner image is transferred but also before the transfer.

4. Furthermore, before charging the toner adhering to the transfer body or the like, the charge eliminating operation may be performed once using the charge eliminating chargers 39 and 40. In this case, the charged state of the toner becomes more uniform, so that even better cleaning can be performed.

As explained above, according to the present invention, by providing the charging means for charging the toner adhering to the transfer member or the intermediate transfer member, the toner becomes charged in a negative state. This has the effect that the cleaning ability of the cleaning means can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view showing the overall structure of a full-color copying machine in the first embodiment, FIG. 2 is a cross-sectional front view showing the structure around the cleaner section, FIG. 3 is a bronch diagram showing the structure of the control device, 4 is a timing chart showing the control operation, FIG. 5 is a cross-sectional front view showing the state of charge on the transfer drum, and FIG. 6 is a cross-sectional front view showing the structure of the photosensitive drum and the vicinity of the transfer belt in the second embodiment. , FIG. 7 is a sectional front view showing the structure of the photosensitive drum and the vicinity of the intermediate transfer belt in the third embodiment. 9... Photosensitive drum, 21, 64, 85... Transfer paper,
30... Transfer drum, 34... Transfer charger, 5
゜...Cleaner section, 63...Transfer belt, 76...
・Intermediate transfer belt, 84...Charger patent applicant Minolta Camera Co., Ltd. Figure 2 Figure 5

Claims (2)

[Claims] (1) A cleaner that cleans toner adhering to a transfer body that transfers toner from a photoreceptor to a recording medium that it holds, a cleaning means that uses electrostatic action to clean toner on the transfer body, and prior to said cleaning, A cleaner comprising a charging means for charging toner on a transfer body. (2) in a cleaner that cleans toner adhering to an intermediate transfer body that further transfers toner transferred from a photoreceptor to a transfer target, a cleaning means that electrostatically cleans toner on the intermediate transfer body; A cleaner comprising a charging means for charging the toner on the intermediate transfer member prior to the cleaning.