KR20080072366A - Image developing unit for image forming apparatus - Google Patents

Abstract

A developing unit for an image forming apparatus is provided to install a developer guide to collect developer moving by a supply roller around the supply roller in a developer storage tub to a developer supply portion between a developing roller and the supply roller, thereby enabling the developer to be attached to the developing roller actively as the density of the developer is increased in the developer supply portion. A developing unit(21) for an image forming apparatus includes a developing roller(31), a developer storage tub(25), and a supply roller(33). The developing roller supplies developer to a photoreceptor(22) where an electrostatic latent image is formed. The developer storage tub stores the developer. The supply roller attaches the developer stored in the developer storage tub to the developing roller. A developer guide(36) is installed to lead the developer around the supply roller during the rotation of the supply roller around the supply roller in the developer storage tube to be collected to a developer supply portion(34) between the developing roller and the supply roller.

Description

Image developing unit for image forming apparatus

1 is a side cross-sectional view schematically showing an image forming apparatus equipped with a developing unit according to an embodiment of the present invention.

2 is a side cross-sectional view showing a developing unit of an image forming apparatus according to an embodiment of the present invention.

3 is a perspective view showing the main components of the developing unit of the image forming apparatus according to an embodiment of the present invention.

4 is an enlarged side cross-sectional view of part A of FIG. 2 to explain the operation of the developing unit of the image forming apparatus according to the exemplary embodiment of the present invention.

5 is a perspective view showing the main part of the developing unit of the image forming apparatus according to another embodiment of the present invention.

<Description of Signs of Major Parts of Drawings>

21 ... developing unit 22 ... photosensitive member

25 ... developer reservoir 27 ... developer reservoir

28.Developer supply room 29.

31 ... developing roller 33 ... feed roller

34 Developer's Supply Unit 35 Developer's Collection Unit

36. Developer guide 37 ... Control member

38.Transmitter

The present invention relates to an image forming apparatus, and more particularly, to a developing unit of an image forming apparatus for forming an image in an electrophotographic manner.

In general, an image forming apparatus is a device for developing a black and white image or a color image on a print medium such as paper according to an image signal, and includes a laser printer, an ink jet printer, a copying machine, a multifunction printer, a facsimile, and the like. The image forming method of the various image forming apparatuses includes an electrophotographic method of scanning a beam on a photosensitive member to form an electrostatic latent image, and attaching a developer thereon to a printing medium, and applying liquid ink on the surface of the printing medium according to an image signal. The inkjet method of spraying is typical.

Among these, an electrophotographic image forming apparatus scans a photosensitive member charged at a constant potential to form an electrostatic latent image on its outer peripheral surface, attaches a toner as a developer to produce a visible image, and then displays the visible image. An apparatus for printing an image by transferring and fixing the image onto a print medium.

The electrophotographic image forming apparatus includes a developing unit that forms a visible image using a developer in accordance with an image signal. The developing unit includes a photosensitive member on which the light scanned by the optical scanning device is incident to form an electrostatic latent image, a developing roller for attaching the developer to the photosensitive member, and a supply roller for supplying the developer stored in the developer storage chamber to the developing roller. Include.

The developing roller and the supply roller are installed to be adjacent to each other to rotate in the same direction, and the developer stored in the developer storage chamber is charged to a certain polarity and then attached to the surface of the developing roller by the supply roller. The developer attached to the surface of the developing roller moves from the developing nip between the photosensitive member and the developing roller to the photosensitive member to form a visible image on the photosensitive member surface.

However, in recent years, as the image forming apparatus and the developing unit have been speeded up and downsized, the rotational speeds of the developing roller and the supply roller have increased. As such, when the rotational speed of the developing roller and the feeding roller increases, the supply of the developer to the developing roller by the feed roller is not smooth, and as a result, the developer is not smoothly supplied to the photosensitive member. In addition, if the developer is not smoothly supplied to the photosensitive member, a problem of deterioration of image quality occurs.

In addition, in recent years, a developer that is attached to a developing roller and is not supplied to the photosensitive member with a long life of the developing unit, and then recovered, becomes a problem. That is, the developer remaining in the developing roller, which is not supplied from the developing roller to the photosensitive member, is recovered in a stressed state by friction with the supply roller, and is mixed with other developers in the developer storage chamber, thereby reducing the developing efficiency of the developing unit.

In addition, when the developer that is not sufficiently charged moves from the developing roller to the photosensitive member, the moving developer is more affected by the flow of air than the electrostatic force, so that it does not move to the image region of the photosensitive member but adheres to or is attached to the non-image region of the photosensitive member. It is scattered into the space and contaminates other parts and the developing efficiency is reduced.

An object of the present invention is to provide a developing unit of an image forming apparatus capable of continuously supplying a developer to a developing roller and reducing a stress of the developer to obtain a good image continuously. .

The developing unit of the image forming apparatus according to the present invention for achieving the above object includes a developing roller for supplying a developer to a photosensitive member on which an electrostatic latent image is formed, a developer storage container for storing the developer, and a developer storage container. And a feed roller for attaching the stored developer to the developing roller, wherein the developer roller and the feed roller are guided around the feed roller in the developer storage container by guiding the developer around the feed roller when the feed roller is rotated. Characterized in that the developer guide is collected to the developer supply unit therebetween.

Here, the interval between the feed roller and the developer guide can be narrowed in the rotation direction of the feed roller.

The developer reservoir is divided into a developer supply chamber inside the developer guide in which the supply roller is accommodated by the developer guide, and a developer storage chamber outside the developer guide. A passage through which the developer can move may be provided between the developer storage chambers.

In addition, a conveyer for conveying the developer in the developer storage chamber to the developer supply chamber may be installed in the passage between the shaper supply chamber and the developer storage chamber.

In addition, at one end of the developer guide, a control member for collecting the developer guided by the developer guide closer to the developer supply unit is installed so as to be spaced apart from the supply roller, the control member and the supply roller If the developer is excessively gathered between the gaps with the supply roller may be opened so that the distance.

In addition, the developer guide may include a terminal for connecting a power source so that the developer guides the developer guided by the developer guide.

Hereinafter, a developing unit of an image forming apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a side cross-sectional view schematically showing an image forming apparatus equipped with a developing unit according to an embodiment of the present invention.

As shown in Fig. 1, the developing unit 21 of the image forming apparatus according to the embodiment of the present invention includes a photosensitive member 22 on which a visible image to be transferred to a printing medium is formed, and the image forming apparatus main body 11 It is installed on the print media movement path therein. In addition to the developing unit 21, the image forming apparatus main body 11 includes a print medium supply device 12, a pickup roller 13, an optical scanning device 14, a transfer roller 15, and a fixing unit 16. And a print medium discharge device 17 are provided.

In the image forming apparatus, when printing starts, the pickup roller 13 rotates to pick up the print media loaded in the print medium supply device 12 in a sheet and transfer it toward the developing unit 21. Then, the optical scanning device 14 scans a beam on the surface of the photoconductor 22 charged at a constant potential in accordance with an image signal to form an electrostatic latent image on the surface of the photoconductor 22. Thereafter, a developer is attached to the electrostatic latent image region on the surface of the photoconductor 22 to form a visible image in powder form, and the visible image is transferred to the surface of the print medium transported by the transfer roller 15. The visible image transferred to the print medium is melted under heat and pressure when the print medium passes through the fixing unit 16 to be fixed on the surface of the print medium, and the print medium passing through the fixing unit 16 is the print medium discharge device 17 Is discharged to the outside of the image forming apparatus main body 11.

As shown in FIG. 2, the developing unit 21 includes a photosensitive member 22 on which an electrostatic latent image is formed, a developing roller 31 for attaching a developer to the photosensitive member 22, and a developer for storing the developer. The storage container 25 and the supply roller 33 for supplying the developer of the developer storage container 25 to the developing roller 31 are included. The cleaning member 24 for removing the developer remaining untransferred around the photosensitive member 22 and the charging roller 23 for charging the surface of the photosensitive member 22 to a predetermined electric potential are provided on the surface of the photosensitive member 22. It is installed to contact each.

The developing roller 31 is installed adjacent to the photoconductor 22 so that the developer attached to the surface thereof can move to the photoconductor 22, and rotates in a direction opposite to the rotation direction of the photoconductor 22 to the surface of the photoconductor 22. The developer is attached to the formed latent electrostatic image area. The developing roller 31 is located inside the developer reservoir 25 so that a developer stored in the developer reservoir 25 can be attached to the surface. A regulating blade 24 is installed adjacent to the developing roller 31 to adjust the thickness of the developer layer attached to the surface of the developing roller 31.

The supply roller 33 attaches the developer stored and installed in the developer storage container 25 to the surface of the developing roller 31. A part of the supply roller 33 is in contact with the surface of the developing roller 31, and a developer is attached to the surface of the developing roller 31 by the supply roller 33 between the supply roller 33 and the developing roller 31. The developer supply part 34 and the developer recovery part 35 which collect | recover the developer which remain | survives on the surface of the developing roller 31 after supplying a developer to the photosensitive member 22 are provided. The developer supply part 34 is provided at an upper portion of the contact portion between the developing roller 31 and the supply roller 33, and the developer recovery part 35 is provided at a portion where the developer roller 31 and the supply roller 33 abut. It is provided at the bottom. The feed roller 33 rotates in the opposite direction to the developing roller 31, carries the developer around the developer roller 34, adheres it to the surface of the developing roller 31, and also the surface of the developing roller 31. The remaining developer, which is not moved to the photosensitive member 22, is removed from the developer collection part 35.

A developer guide 36 for guiding the developer around the feed roller 33 is provided around the feed roller 33 inside the developer reservoir 25. As shown in Figs. 2 and 3, the developer guide 36 has a length similar to that of the feed roller 33 and has a gently curved shape to correspond to the round surface of the feed roller 33. As shown in Figs. The developer guide 36 in the form of a round curved plate is installed on the upper part of the feed roller 33 so as to be somewhat spaced apart from the feed roller 33, and one end thereof is developed between the developing roller 31 and the feed roller 33. It comes to the vicinity of the provision payment 34. The distance between the developer guide 36 and the supply roller 33 is narrowed in the rotational direction of the feed roller 33 so as to be minimum at the end close to the developer supply part 34. Therefore, when the feed roller 33 rotates, the developer around the feed roller 33 is guided by the developer guide 36 and collected toward the developer supply part 34.

At the end of the developer supply part 34 of the developer guide 36, an adjusting member 37 for collecting the developer guided by the developer guide 36 toward the developer supply part 34 is provided. 34) is installed. The adjusting member 37 is formed in the form of a flexible thin film, and is spaced apart from the surface of the supply roller 33 but is installed to reduce the separation width toward the developer supply part 34.

Therefore, the developer guided by the developer guide 36 and the adjusting member 37 by the rotation of the feed roller 33 increases in density as the developer feeder 34 approaches the developer roller 31. Developer supply is active. When the developer is excessively collected between the adjusting member 37 and the supply roller 33, since the developer movement to the developer supply part 34 may not be performed smoothly due to a bottleneck, the adjusting member 37 is supplied. If the developer excessively collects between the rollers 33, the pressure is increased so that the distance from the supply rollers 33 is increased.

As shown in FIG. 2, the developer guide 36 and the adjusting member 37 accommodate the supply roller 33 as shown in FIG. 2 by the developer guide 36 and the adjusting member 37. The developer supply chamber 28 inside the) and the developer storage chamber 27 outside the developer guide 36 and the adjusting member 37 are partitioned. The other end of the developer guide 36 is separated from the bottom surface of the developer storage container 25 so that a passage 29 through which the developer can move between the developer supply chamber 28 and the developer storage chamber 27 is formed. do.

The passage 29 is provided with a conveying machine 38 for conveying the developer in the developer storage chamber 27 to the developer supply chamber 28. The conveyer 38 includes a plurality of vanes 39 for pushing the developer, and rotates in a direction to convey the developer in the developer storage chamber 27 between the supply roller 33 and the developer guide 36. do. The conveyer 38 rotates to supply the developer to the developer supply chamber 28 and at the same time the developer, which is moved by the feed roller 33 from the developer supply chamber 28, exits through the passage 29. Prevent it. One side of the developer storage chamber 27 is provided with an agitator 26 for stirring the developer.

When the printing unit 21 of the image forming apparatus according to the present invention starts printing, as shown in FIG. 4, the developing roller 31 rotates from the developer collection unit 35 toward the developer supply unit 34. The supply roller 33 is in contact with the developing roller 31 and rotates in the opposite direction. Then, the conveyer 38 rotates to convey the developer in the developer storage chamber 27 to the developer supply chamber 28.

At this time, the developer around the supply roller 33 of the developer supply chamber 28 is guided by the developer guide 36 and the adjusting member 37 and collected by the developer supply unit 34 to be active in the developer roller 31. Is attached. Then, the developer remaining on the surface of the developing roller 31 without being moved to the photosensitive member 22 is separated by the supply roller 33 from the developer collection part 35, and again, the supply roller 33 and the developer guide ( 36) is moved between.

As described above, in the developing unit 21 of the image forming apparatus according to the present invention, the developer moving by the supply roller 33 is developed between the developing roller 31 and the supply roller 33 by the developer guide 36. The developer can be sufficiently supplied to the developing roller 31 because it is collected by the provision supply part 34. Then, the developer that is not moved to the photosensitive member 22 and is removed from the developing roller 31 does not move to the developer storage chamber 27 in which new developer is stored, and the developer roller 31 again in the developer supply chamber 28. Is attached to. Therefore, since the rubbing and charged developer is used first and the new developer is stored in an unused state, the developing efficiency of the developing unit 21 is not increased even though the overall stress of the developer in the developer storage container 25 is not increased even when used for a long time. Does not fall.

5 schematically shows a developing unit of an image forming apparatus according to another embodiment of the present invention.

The developing unit 41 according to another embodiment of the present invention shown in FIG. 5 has the same configuration as that of the developing unit 21 according to the above embodiment. The developing roller 51 and the supply roller 53 are the same. And a developer guide 56 and a conveyer 59. Here, since the rest of the configuration except for the developer guide 56 is the same as the developing unit 21 according to the embodiment, detailed description of components other than the developer guide 56 will be omitted.

One end of the developer guide 56 is provided with an adjusting member 57 for guiding the guided developer closer to the developer supply unit (not shown) between the developer roller 51 and the supply roller 53. The developer guide 56 is made of a conductive material through which electricity can flow, and has a terminal portion 58 for receiving power.

In the developing unit 41 according to another embodiment of the present invention, the developer guide 56 collects the developer around the supply roller 53 into a developer supply unit between the developing roller 51 and the supply roller 53. As well as the power supply to the developer guide 56, the developer guided by the developer guide 56 can be sufficiently charged. Therefore, developing efficiency can be further improved.

According to the present invention described above, since the developer guide for collecting the developer moving by the feed roller around the feed roller in the developer storage container to the developer supply portion between the developer roller and the feed roller is provided, Developer density increases. Therefore, the developer can be actively attached to the developing roller.

In addition, according to the present invention, since the developer which is not moved to the photoconductor and is recovered from the developing roller is used first without being mixed with other unused developer inside the developer storage container, the stress of the developer inside the developer storage container is increased when used for a long time. Since it does not increase, a good developing efficiency can be obtained continuously.

In addition, according to the present invention, since the developer can be sufficiently charged before development, good development efficiency can be obtained even if printing is performed at high speed.

The present invention described above is not limited to the configuration and operation as illustrated and described. That is, the present invention is capable of various changes and modifications within the spirit and scope of the appended claims.

Claims (6)

And a developing roller for supplying the developer to the photosensitive member on which the electrostatic latent image is formed, a developer storage container for storing the developer, and a supply roller for attaching the developer stored in the developer storage container to the developing roller. In the developing unit, A developer guide is provided around the supply roller in the developer storage container to guide the developer around the supply roller to collect the developer supply unit between the developer roller and the supply roller when the supply roller is rotated. A developing unit of an image forming apparatus. The method of claim 1, And the interval between the feed roller and the developer guide is narrowed in the rotational direction of the feed roller. The method of claim 2, The developer storage compartment is divided into a developer supply chamber inside the developer guide in which the supply roller is accommodated by the developer guide, and a developer storage chamber outside the developer guide, wherein the developer supply chamber and the developer A developing unit of the image forming apparatus, wherein a passage through which the developer moves is provided between the storage chambers. The method of claim 3, wherein And a conveyer for conveying the developer in the developer storage chamber to the developer supply chamber in the passage between the shaper supply chamber and the developer storage chamber. The method of claim 2, At one end of the developer guide, an adjustment member for collecting the developer guided by the developer guide closer to the developer supply unit is installed to be spaced apart from the supply roller, and the adjustment member is disposed between the supply roller. Developing unit of the image forming apparatus, characterized in that a gap is formed so as to be spaced apart from the supply roller. The method of claim 2, And the developer guide has a terminal for connecting power so that the developer guide can charge the developer guided by the developer guide.

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