Patent Application
20070048028
This application claims the benefit under 35 U.S.C. ยง 119(a) of Korean Patent Application No. 10-2005-0078911, filed on Aug. 26, 2005, in the Korean Intellectual Property Office, the entire disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an electrophotographic image forming apparatus. More particularly, the present invention relates to a developer including a plurality of developing cartridges and a plurality of toner cartridges that are sequentially driven to form a multi-color image and an electrophotographic image forming apparatus including the same.
2. Description of the Related Art
In general, electrophotographic image forming apparatuses form an electrostatic latent image corresponding to a desired image on a photosensitive medium by radiating light onto the photosensitive drum charged to a predetermined potential. The electrostatic latent image is developed using toner to form a toner image. The toner image is transferred onto a sheet of paper and the toner image is fused on the paper, thereby forming the desired image.
A multi-color image forming apparatus generally requires yellow (Y), magenta (M), cyan (C), and black (B) toners. These color toners overlap each other to exhibit a desired multi-color image. Accordingly, the multi-color image forming apparatus requires four developing cartridges for storing respective color toners.
The multi-color image forming apparatus having the four developing cartridges has a larger size and a more complicated structure, compared with a monochromic image forming apparatus for exhibiting a single color.
Each of the developing cartridges has various components, such as a toner storing unit for storing a toner, an agitator for agitating the toner, a developing roller for developing an electrostatic latent image, and a feeding roller for feeding the toner to the developing roller. When the toner is used up, the developing cartridge should be replaced with a new developing cartridge.
The life span of the toner is shorter than those of the other components. Accordingly, if the toner is used up, the developing cartridge should be replaced with a new developing cartridge although the other components thereof can be still used.
Accordingly, a method of feeding only toner to extend the life span of the developing cartridge has been suggested. A toner cartridge for storing toner therein and a developing cartridge are separately provided. When the toner is used up, only the toner cartridge is replaced with a new toner cartridge to feed new toner to the developing cartridge. Thus, the developing cartridge can be used until its life span.
At this time, the developing cartridges and the toner cartridges must be disposed in the image forming apparatus such that they efficiently perform the respective functions by detachably providing the toner cartridges to the developing cartridges, and the toner stored in the toner cartridge must be stably fed to the developing cartridge.
Accordingly, the toner cartridges and the developing cartridges should not interfere with one another, and the total size of the image forming apparatus should be reduced.
Furthermore, the toner should not directly drop from the toner cartridge onto the developing cartridge using free fall in a layout of the image forming apparatus. The toner must be smoothly fed to the developing cartridge although a large distance may exist between where the toner drops and a component of the developing cartridge.
Accordingly, a need exists for an electrophotograhic image forming apparatus having an improved developer having separate developing and toner cartridges.
The present invention provides a developer and an electrophotographic image forming apparatus in which the total size of the image forming apparatus may be reduced by separately providing a plurality of developing cartridges and a plurality of toner cartridges.
According to an aspect of the present invention, a developer includes a developer frame, a plurality of developing cartridges that are sequentially mounted in the developer frame and have a plurality of toner feeding units for receiving respective toners, and a plurality of toner cartridges that feed the respective toners to the plurality of toner feeding units, respectively. A toner cartridge frame is detachably mounted in the developer frame and in which the plurality of toner cartridges are mounted.
Other objects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:
Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements, features, and structures.
Referring to
The photosensitive drum 10 has a photoconductive layer formed on the outer circumferential surface of a cylindrical metal drum. Instead of the photosensitive drum 10, a photosensitive belt may be employed. A charging roller 11, which is an example of a charger for charging the photosensitive drum 10 to a uniform potential, is disposed adjacent to the photosensitive drum 10. A cleaning means 12 is provided for removing waste toner remaining on the surface of the photosensitive drum 10 after transferring an image onto the intermediate transfer belt 61.
The charging roller 11 supplies charges to the photosensitive drum 10 while rotating in contact with or in non-contact with the outer circumferential surface of the photosensitive drum 10 to make the outer circumferential surface of the photosensitive drum 10 have a uniform potential. Instead of the charging roller 11, a corona charger may be employed. An exposure unit 50 irradiates light corresponding to image information onto the photosensitive drum 10 charged to the uniform potential to form an electrostatic latent image. The exposure unit 50 generally includes a laser scanning unit (LSU) using a laser diode as a light source.
The plurality of toner cartridges 30Y, 30M, 30C, and 30K contain toners of yellow (Y), magenta (M), cyan (C), and black (K), respectively. The plurality of developing cartridges 20Y, 20M, 20C, and 20K receive the respective color toners from the plurality of toner cartridges 30Y, 30M, 30C, and 30K, and develop the electrostatic latent image formed on the photosensitive drum 10.
Each of the developing cartridges 20 includes a developing roller 21 spaced apart from the photosensitive drum 10 by a development gap. The development gap may be several tens or several hundreds of microns.
The image forming apparatus according to an exemplary embodiment is a multi-pass type image forming apparatus in which the plurality of developing cartridges 20Y, 20M, 20C, and 20K are sequentially driven to form an image. In this multi-pass type image forming apparatus, a development bias may be applied to the developing roller 21K of a selected developing cartridge 20K and may not be applied to the developing rollers 21Y, 21M, and 21C of the other developing cartridges 20Y, 20M, and 20C, or a development preventing bias may be applied to the developing rollers 21Y, 21M, and 21C of the other developing cartridges 20Y, 20M, and 20C. Alternatively, only the developing roller 21K of the selected developing cartridge 20K may rotate and the developing rollers 21Y, 21M, and 21C of the other developing cartridges 20Y, 20M, and 20C do not rotate.
As shown in
That is, since at least portions of three developing cartridges 20M, 20C, and 20K share heights with the developing cartridges 20Y, 20M, and 20C, respectively, the increase in the height of the image forming apparatus due to the plurality of toner cartridges 30Y, 30M, 30C, and 30K may be minimized. Furthermore, the plurality of toner cartridges 30Y, 30M, 30C, and 30K may be disposed such that they do not interfere with each other or with the developing cartridges 20Y, 20M, 20C, and 20K. Thus, as shown in
Referring to
The photosensitive drum 10 may be detachably mounted in the developer frame 41 and the life span of the developer 40 depends on the life span of the photosensitive drum 10.
Referring to
The developing roller 22 develops the electrostatic latent image formed on the photosensitive drum 10 using the toner to form an image. A control blade 26 for controlling the thickness of the toner adhered to the outer circumferential surface of the developing roller 22 is disposed above the developing roller 22. The control blade 26 covers the receiving unit 21 to protect the receiving unit 21. The developing roller 22 is exposed outside of the receiving unit 21 and faces the photosensitive drum 10.
The feeding roller 23 adheres the toner (non-magnetic toner) to the developing roller 22, such as by triboelectrification, while rotating in contact with the developing roller 22.
The plurality of augers 24 receive the toner from the toner feeding unit 25 and feed the toner to the developing roller 22. A plurality of rotary wings 24a are provided in the plurality of augers 24. The conveying directions of the plurality of the augers 24 may be opposite to each other.
The toner feeding unit 25 extends rearwardly from the receiving unit 21 by a predetermined length. A feeding hole 33 for receiving the toner from each of the toner cartridges 30 is provided in the upper surface of the toner feeding unit 25. An outlet 32 corresponding to the feeding hole 33 is provided in each of the toner cartridges 30. Each of the toner cartridges 30 includes a shutter (not shown) for opening or shutting the outlet 32. When each toner cartridge 30 is mounted in each developing cartridge 20, the shutter (not shown) opens the outlet 32 such that the toner is fed to the toner feeding unit 25. When each toner cartridge 30 is removed from each developing cartridge 20, the shutter shuts the outlet 32 such that the toner is substantially prevented from being fed to the toner feeding unit 25.
A driving gear train 27 for driving the developing roller 22, the feeding roller 23, and the plurality of augers 24 is provided at one side of each of the developing cartridges 20. The driving gear train 27 may have a height less than the height (H) of each developing cartridge 20. To this end, the plurality of developing cartridges 20 may be disposed such that they overlap each other in a vertical direction, as shown in
The driving gear train 27 includes a main gear 27a provided on the shaft 23a of the feeding roller 23. A developing roller gear 27c is connected to the main gear 27a for receiving the power from the main gear 27a. A feeding roller gear 27b is disposed on the shaft 23a of the feeding roller 23 for transferring the power to the plurality of augers 24 when the shaft 23a of the feeding roller 23 rotates. Accordingly, the main gear 27a rotates by external power to drive the developing roller 22, the feeding roller 23, and the plurality of augers 24.
A power supply unit 28 for supplying a voltage to the components is disposed at the other side of each of the developing cartridges 20. The power supply unit 28 is provided at the back side of each of the developing cartridges 20 toward the toner feeding unit 25.
Furthermore, a first guide portion 29a is provided at one side of each of the developing cartridges 20, that is, the side having the driving gear train 27; and a second guide portion 29b is disposed at the other side of each of the developing cartridges 20, that is, the side having the power supply unit 28. The first guide portion 29a and the second guide portion 29b may be provided at the front side of each of the developing cartridges 20.
Referring to
Referring to
Referring to
At this time, the plurality of first guide portions 29a and the plurality of second guide portions 29b disposed in the plurality of developing cartridges 20 are mounted and fixed in a plurality of first guide grooves 3 and a plurality of second guide grooves 4 formed in the main frame 1. That is, the plurality of first guide portions 29a slide along the plurality of first guide grooves 3 and the plurality of second guide portions 29b slide along the plurality of second guide grooves 4. Accordingly, the developer 40 is mounted in the main frame 1.
Accordingly, when the developer 40 is mounted in the main frame 1, the developer 40 is always positioned at any one location of the main frame 1 by the first guide grooves 3 and the second guide grooves 4 such that it can be aligned with the other components such as the transfer belt 61 and so on (see
Referring to
Referring back to
Accordingly, the developer 40 is mounted at a predetermined location of the main frame 1 using the first guide grooves 3, the second guide grooves 4 and the locking device 2 provided in the main frame 1.
As described above, in a developer and an electrophotographic image forming apparatus according to exemplary embodiments of the present invention, the developing cartridges and the toner cartridges are separately provided and thus the size of the electrophotographic image forming apparatus may be reduced. Furthermore, because the developer may be mounted at a predetermined location of a main frame, the interaction with the other components may be smoothly realized.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2005-0078911 | Aug 2005 | KR | national |
