The present application claims priority to and incorporates by reference the entire contents of Japanese priority documents 2006-283258 filed in Japan on Oct. 18, 2006 and 2007-220649 filed in Japan on Aug. 28, 2007.
1. Field of the Invention
The present invention relates to a toner conveyer device that conveys waste toner.
2. Description of the Related Art
In conventional image forming apparatuses such as copiers, facsimile machines, and printers, a service staff generally carries out replacement of consumable or life-limited components and maintenance of them. However, the trend is changing and the user is carrying out exchange of supplies and maintenance. In addition, smaller components are used for suppressing the size and the cost of the image forming apparatus. Therefore, the user needs to periodically exchange parts that deteriorate in quality earlier than the life of the apparatus or a waste-toner container. The waste-toner container contains residual materials such as toner, which is a developer, or fiber from transfer sheets. Moreover, because the image forming apparatus is installed adjacent to a user of a personal computer in the times of widespread use of personal computers reduction of noise during operation of the image forming apparatus is another problem that needs attention.
Toner that fails to be transferred onto the transfer sheet is removed and conveyed into a waste-toner container. To recycle the waste toner, an additional path and an additional driving unit for collecting the waste toner becomes necessary. As a result, the image forming apparatus becomes larger. The waste toner contains foreign materials such as fiber from the transfer sheets. Removal of the fiber makes control process or reuse process complicated. If a full-color image forming apparatus that uses three or four toners performs the waste-toner recycling process, considerably larger waste-toner container is required so that structure of the full-color image forming apparatus becomes much complicated. For this reason, in some of the image forming apparatuses, the waste toner is just conveyed into the waste-toner container and the waste-toner container is replaced with another one when the waste-toner container is full with the waste toner.
It is possible to provide a waste-toner container that can contain all the waste toner generated during a whole life of the apparatus. However, such a waste-toner container is considerably large. Therefore, there is a need for filling the waste toner into the waste-toner container in an effective manner to decrease the frequency of replacing the waste-toner container. The waste toner is poured into the waste-toner container from the top, and a sensor is installed on the top part of the waste-toner container. The sensor is a detecting unit for detecting whether the waste-toner container is filled to its capacity and for notifying time of exchange. Exchange cycle of the waste-toner container is prolonged if the waste-toner container is filled with the waste toner without an unfilled space, that is, the waste toner does not accumulate in one particular part of the waste-toner container.
In the conventional image forming apparatus two methods are used to properly fill up the waste-toner container. One method is to periodically shake the waste-toner container and the other method is to locate an agitating screw on the top part of the waste-toner container to flatten a pile of the waste toner inside the waste-toner container.
Japanese Patent Application Laid-open No. H11-327397 discloses an image forming apparatus that includes an photoconductor, a cleaning device that cleans a toner-image formation surface of the photoconductor, a cleaner case (waste-toner conveyer path) that conveys the waste toners removed by the cleaning device, and a toner conveyer screw (screw member) that conveys the waste toners. The image forming apparatus further includes a hammer member (impact-pressure making unit) that gives an impact to the cleaner case or the toner conveyer screw. The hammer member gives an impact when the image formation process is not performed by the photoconductor. More particularly, in the cleaner case there is an elastic projection arranged in contact with a thread of the toner conveyer screw. When the toner conveyer screw is rotated, the projection is brought into contact with the thread in an electrical manner to give vibration to the toner conveyer screw. Then, the toner adhered to the toner conveyer screw falls due to the vibration, thus preventing decrease of a conveyable waste-toner amount.
Japanese Patent Application Laid-open No. 2002-241569 discloses a residual-toner recovery device for use in an image forming apparatus that includes a residual-toner dropping path through which the residual toners fall down and a conveyer path that connects between the residual-toner dropping path and the residual-toner recovery container. The toner adhered to a peripheral surface of a toner-image forming unit are removed from the toner-image forming unit by a cleaning mechanism and fall down through the residual-toner dropping path. A residual-toner conveyer mechanism includes a sweep roller having an elliptical cross section, positioned near the connection with the conveyer path in the residual-toner dropping path, and a scraper made of a flexible member, having the distal end pressed against the peripheral surface of the sweep roller in the return side of the rotation direction, with the proximal end of the scraper fitted to the inner wall of the residual-toner dropping path. The scraper is formed with a recess at parts other than the part which is in contact with the sweep roller. With this arrangement, the increase of the internal pressure of the residual-toner dropping path on which the return side of the sweep roller in the rotation direction is positioned can be suppressed, while maintaining the toner-scrape performance of scraping the toners adhered to the sweep roller positioned in the residual-toner dropping path.
However, in the conventional image forming apparatus, collected waste toner accumulates unevenly in the waste-toner container, and space in the waste-toner container is not effectively filled.
Moreover, electrophotographic devices have become smaller so that a range of users has become broader. However, a shorter conveyance path makes it difficult to maintain efficiency in conveying waste toner. There is a need for improving the efficiency.
It is an object of the present invention to at least partially solve the problems in the conventional technology.
According to an aspect of the present invention, there is provided a toner conveyer device for use in an image forming apparatus. The toner conveyer device includes a toner conveyer belt that conveys waste toner; a screw member that receives the waste toner from the toner conveyer belt and conveys the waste toner to a housing unit; and a scraping member that scrapes waste toner that adheres to the screw member.
According to another aspect of the present invention, there is provided a process cartridge that is detachable from an image forming apparatus. The process cartridge includes a photoconductor that carries a latent image; a cleaning device that removes waste toner remaining on the photoconductor; and the toner conveyer device described above.
According to still another aspect of the present invention, there is provided an image forming apparatus that includes a photoconductor that carries an electrostatic latent image; a developing device that receives toner from a developing-agent carrier and develops the latent image with the toner to form a toner image; a transfer device that transfers the toner image onto a recording medium; a cleaning device that removes residual waste toner from the photoconductor; and the above toner conveyer device.
The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.
Exemplary embodiments of the present invention will be explained below with reference to the accompanying drawings.
Relevant parts of the color-image forming apparatus 10 are explained with reference to
A core metal of each developing roller 32 of each of the developing device 31 is applied with a bias voltage of a negative potential overlapping an alternating current and a direct current from a bias power source (not shown). Each charging roller 21 is applied with a bias voltage with negative potential of a direct current by another bias power source. The photoconductor 22, the developing device 31, the cleaning blade 23, and the charging roller 21 form the image forming unit 20. The image forming apparatus 10 includes the four image forming units 20 of a first image forming unit 20a, a second image forming unit 20b, a third image forming unit 20c, and a fourth image forming unit 20d.
The cleaning blade 23a cleans the photoconductor 22a to remove residual waste toner on the peripheral surface of the photoconductor 22a. The charging roller 21a initializes the photoconductor 22a, by uniformly charging at a high potential on the peripheral surface of the photoconductor 22a after the cleaning process. The laser beam 36a is irradiated onto the photoconductor 22a of the first image forming unit 20a. The laser beam 36b is irradiated onto the photoconductor 22b of the second image forming unit 20b. Accordingly, the peripheral surface of the photoconductor 22a uniformly charged with the high potential is selectively exposed based on image data. As a result, a potential of a part that is subjected to the exposure becomes low and a potential of another part that is not subjected to the exposure remains high. Thus, by using difference in potential, an electrostatic latent image is formed on the peripheral surface of the photoconductor 22a. This operation is performed in a similar manner by the second image forming unit 20b to the fourth image forming unit 20d. The developing device 31a applies the toner onto the low-potential part (or the high-potential part) of the electrostatic latent image, to form (develop) a toner image.
The photoconductor 22a rotates and conveys the toner image, and transfers the image to the intermediate transfer belt 28. The second image forming unit 20b similarly operates in the timing that the toner image on the intermediate transfer belt 28 comes to a contact part of the photoconductor 22b at which the toner image is contacted to the photoconductor 22b. The developing device 31b forms a toner image by developing the electrostatic latent image on the photoconductor 22b. The photoconductor 22b conveys the toner image by rotation, and transfers the toner image in superimposition onto the toner image on the intermediate transfer belt 28. A similar operation is performed by the third image forming unit 20c and the fourth image forming unit 20d. A quadruple toner image is conveyed, and is transferred onto paper (not shown) by a secondary-transfer roller 39.
A paper feeding roller 37 and a conveyer roller 38 convey the transfer paper into the body of the image forming apparatus 10. The secondary-transfer roller 39 transfers the toner image formed on the intermediate transfer belt 28 onto the transfer paper.
The transfer paper transferred with the toner image is conveyed to a fixing unit 60. A fixing nip unit formed by the fixing roller of the fixing unit 60 and a pressing roller fixes the toner image. A discharging roller 61 positioned downstream in the transfer-paper conveyance direction of the fixing unit 60 discharges the transfer paper to a catch tray 62 located on the upper surface of the body of the image forming apparatus 10. The cleaning blade 23 that is in contact with the intermediate transfer belt 28 cleans the intermediate transfer belt 28 by removing residual toners on the intermediate transfer belt 28 in a similar manner that the cleaning blade 23 cleans the photoconductor 22. The waste toners are collected into the waste-toner housing unit 58 via a toner conveyer path 50.
The waste-toner housing unit 58 is detachable from the body of the image forming apparatus 10, and can be suitably replaced.
Each toner container, the intermediate transfer belt 28, and each imaging cartridge are positioned on the body of the image forming apparatus 10, with an inclination to the same direction, thereby decreasing the total length of the body of the image forming apparatus 10 to decrease the size of the image forming apparatus 10. Particularly, according to the present embodiment, among the image forming units 20, the image forming unit 20a that forms the black toner image is positioned at the transfer nip side, and the image forming unit 20a is inclined to be located at a lower position than the image forming unit 20d. Because the frequency of forming an image using only the black color is high among the colors, the image forming unit 20a is positioned at the transfer nip side, to decrease the printing time of the black image.
When the toner conveyer device 59 is mounted on the body of the image forming apparatus 10, a surface of the toner conveyer device 59 facing members provided on the body of the image forming apparatus 10 is formed in a shape corresponding to the opposing member. When the cleaning blades 23 are provided with an inclination within the body of the image forming apparatus 10, the opposing surface of the toner conveyer device 59 is parallel with the inclination surface inclined in the same direction as that of a line connecting between each cleaning blade 23 of each cleaning unit, and parallel with the line connecting between each cleaning blade 23 of each cleaning unit.
A toner scraping mechanism according to an embodiment of the present invention is explained below.
A course along which the collected toner is conveyed is explained with reference to
Waste toner that fails to be transferred onto the transfer sheet is removed by the cleaning device, and is conveyed in a direction as shown in arrow A to the toner conveyer device 59 that is provided one side of the image forming apparatus 10 or the process cartridge.
After that, the waste toner is conveyed in a direction as shown in arrows B and C to the toner conveyer screw 43 while being held in a gap between the convex part 41 of the toner conveyer belt 25 and the inner wall 51 of the toner conveyer path 50.
The waste toner is then conveyed in a direction as shown in arrow D in
Salient features of the embodiment are explained below with reference to
The driving source of the toner conveyer device 59 is explained below. The toner conveyer device 59 is driven by using the developing device 31 and the photoconductor 22. With this arrangement, units of the toner conveyer device 59 can be easily integrated with each other, and an additional driving source is unnecessary.
A driving mechanism in a state that the toner conveyer device 59 is integrated with a process cartridge including the developing device 31 and the photoconductor 22 is explained below.
This driving force is used to rotate the toner conveyer belt 25 via the conveyer-belt driving shaft 47. An end of the toner conveyer screw 43 opposite to an end having the toner conveyer-screw gear 54 is a free end, so that all the above driving units can be arranged at one side. As a result, it is possible to produce a small process cartridge in which the toner conveyer device 59 is arranged a side opposite to the side where the driving units are arranged.
As explained above, the process cartridge includes the toner conveyer device, thereby decreasing the size of the process cartridge, without generating clogging of toners. Therefore, always a satisfactory printer image (copy image) can be provided. Because the process cartridge is detachable from the image forming apparatus, maintenance and replacement operation of the process cartridge can be easier.
Furthermore, the space in which toners are pooled is substantially eliminated other than the toner conveyer path, by increasing the width of the wall 56 provided within the space encircled by the toner conveyer belt 25, and by providing a wall 56a to be in contact with the toner conveyer belt 25, as shown in
As shown in
According to an embodiment of the present invention, the toner scraping member removes toners adhered to a surface of the screw, thereby an amount of toner that is conveyed by the screw does not decrease.
Moreover, a single toner conveyer device conveys new toners and the waste toners. Therefore, it is possible to use the process cartridge for a long time, and an operation for replacing the process cartridge becomes easier.
Furthermore, because an amount of toner that is conveyed by the screw does not decrease, the stable cleaning performance can be maintained for a long time.
Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.
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2006-283258 | Oct 2006 | JP | national |
2007-220649 | Aug 2007 | JP | national |
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