Patent Application
20050207781
Image forming devices require user intervention for proper operation. One user intervention is clearing the media path during a paper jam. Access to the media path is often difficult because of the complex mechanical design in existing devices. The media path may be located within the interior of the device making it very difficult to remove a jammed media sheet. Further, the user may have access to a limited section of the media path and be able to remove only a portion of the jammed media sheet. A torn remainder is left in the device that must somehow be removed prior to restarting image formation.
Another user intervention requires mounting cartridges within the device. Cartridge mounting may occur initially when the machine is first used, or throughout the device life to replace exhausted cartridges. The complex design again makes it difficult for the user to access the cartridges. Difficult cartridge mounting locations may also result in the user getting toner on their hands and fingers by inadvertently contacting the toner outlet on the cartridge.
Some existing devices provide for an adjustable media path and cartridge mounts to ease the user intervention. The media path and cartridge mounts may be positionable between an operational position during image formation, and a non-operational position to ease user access for media jam removal and cartridge installation respectively. It is important that these adjustable elements be accurately located in the operational position. Inaccurate locating of the elements may result in image forming defects, increased media jams, and other detrimental effects.
Further, the device should be constructed in an economical manner. Price is one of the leading factors when a user makes a purchasing decision. Improvements to user intervention should add to functionability, but not at a price that will drive away potential users.
The present invention is directed to an image forming device having a main body and a movable subunit. In one embodiment, the subunit is movable between a first orientation that is spaced from the main body, and a second orientation that is either in contact with or closely located to the main body. A developer member is positioned within the main body, and a photoconductive member is positioned on the subunit. In the first orientation, the developer member and photoconductive member are spaced apart. Image formation occurs when the subunit is in the second orientation as toner is transferred from the developer member to the photoconductive member.
In one embodiment, an imaging device is positioned within the main body. One or more photoconductive members are positioned on a subunit that is movable relative to the main body. In a first orientation, the photoconductive members are spaced from the imaging device. In a second orientation, the photoconductive members are positioned within the main body and the imaging device can form an electrostatic latent image on the photoconductive members during image forming operations.
In another embodiment, a developer unit is located within the main body. The developer unit may include one or more of a developer member, toner sump, and agitating members. A photoconductive unit is connected to the subunit and may include one or more of a photoconductive member, a charger, a cleaning unit, and an auger. When the subunit is in a first orientation, the developer units and the photoconductive units are accessible to a user. In a second orientation, the subunit is closed and the photoconductive member of each photoconductive unit is mounted against a developer member of each developer unit.
Media sheets are moved from the input and fed into a primary media path. One or more registration rollers disposed along the media path aligns the print media and precisely controls its further movement along the media path. A media transport belt 20 forms a section of the media path for moving the media sheets past a plurality of image forming units 100. Color printers typically include four image forming units 100 for printing with cyan, magenta, yellow, and black toner to produce a four-color image on the media sheet.
An imaging device 22 forms an electrical charge on a photoconductive member within the image forming units 100 as part of the image formation process. The media sheet with loose toner is then moved through a fuser 24 that adheres the toner to the media sheet. Exit rollers 26 rotate in a forward or a reverse direction to move the media sheet to an output tray 28 or a duplex path 30. The duplex path 30 directs the inverted media sheet back through the image formation process for forming an image on a second side of the media sheet.
The image forming units 100 are constructed of a developer unit 40 and a photoconductor unit 50. The developer unit 40, including a developer member 45, is positioned within the main body 12. The photoconductor unit 50, including a photoconductive member 51, is mounted to the subunit 13. In a closed orientation as illustrated in
The photoconductor unit 50 is illustrated in
In this two-piece cartridge architecture, the developer unit 40 and photoconductor unit 50 are mounted to ensure good contact axially across a print zone between the developer member 45 in the developer unit 40 and the photoconductive member 51 in the photoconductor unit 50. The mounting of each of the developer unit 40 and photoconductor unit 50 is important for the axial contact.
The developer unit 40 is located within the main body 12 along three separate dimensional planes. In a first plane, feet 81 extend from two sides of the developer unit 40. One or more rollers 83 are positioned within the main body 12 and extend outward to support the feet 81. In one embodiment illustrated in
In a second plane, the developer unit 40 is biased by a plurality of electrical contacts 85 that include a biasing mechanism 84 mounted to the main body 12. The electrical contacts 85 apply a force outward from the main body 12 (i.e., towards the right as illustrated in
Developer unit 40 is located in a third plane by a biasing force applied against a pad 86 on a first side. The force is applied to the pad 86 by a roller 89 within the main body 12 to force the developer unit 40 laterally within the main body 12 (i.e., into the page as illustrated in
The locating features that bias the developer unit 40 along the three separate dimensional planes allow the unit 40 to move in all three directions instead of being rigidly locked in a fixed position. This allows the nip force acting on the developer member 45 when contacting the photoconductive member 51 to position the developer unit 40 such that the developer member 45 axially contacts the photoconductive member 51 completely and with the necessary nip force.
The photoconductor unit 50 attaches to the subunit 13 as illustrated in
When the subunit 13 is in the closed orientation, the photoconductor unit 50 is located along three dimensional planes. In a first plane, ball bearings 90 are positioned at each end of the photoconductor member 51. The ball bearings 90 locate within a block 91 within the main body 12. In one embodiment as illustrated in
The photoconductor unit 50 is located in a second plane via stop features 92. The stops 92 are positioned in the housing 56 of the photoconductor unit 50 and ensure the correct rotational position of the photoconductive member 50 onto the developer member 45. When the subunit 13 is moved to the closed orientation and torque is applied to the coupler 99 from a driving mechanism within the main body 12, the photoconductor unit 50 rotates and is located by the stops 92 seating against the ends of guide rails 82 in the main body 12 (
Location in a third plane is established through a v-notch feature 93 in the photoconductor unit 50. The v-notch features includes first and second edges that straddle a mating point 95 in the main body. In one embodiment, a v-notch feature 93 is positioned at opposing ends of the photoconductor unit 50 and each mates with a corresponding mating point 95 within the main body 12.
When the device 10 is in the open orientation, the developer units 40 can be individually removed and replaced as necessary. By way of example and using the embodiment of
The subunit 13 results in locating the photoconductive units 50 relative to the corresponding developer units 40. As the subunit 13 closes and the driving mechanism in the main body rotates the coupler 99, the photoconductive units 50 are located along the three dimensional planes. The developer units 40 are located along the three planes as the photoconductive member 51 abuts against the developer member 45. This positioning of the photoconductive member 51 against the developer member 45 allows for toner to pass during the image formation process. In one embodiment, the only contact between the mating developer units 40 and photoconductive units 50 is the contact between the developer members 45 and the photoconductive members 51.
The design provides for most of the developing forces acting on the image forming units 100 to be developed when the subunit 13 is initially placed into the closed orientation. For the developing unit 40, forces are applied along each of the three planes. For the photoconductor unit 50, the forces are completed once torque is applied through the coupler 99 and the stops 92 seat against the ends of guide rails 82 to completely locate the unit with the developer member 45 in contact with the photoconductive member 51. Once the subunit 13 is opened, the forces are removed as the photoconductive member 51 moves away from the developer member 45.
A two-piece cartridge design with pivoting subunit is disclosed in concurrently filed U.S. Patent Application Ser. No. ______ titled “Image Forming Apparatus having a Door Assembly and Method of Use” (Attorney Docket No. 4670-261) which is assigned to Lexmark International, Inc., and incorporated herein by reference in its entirety.
The term “image forming device” and the like is used generally herein as a device that produces images on a media sheet 50. Examples include but are not limited to a laser printer, ink-jet printer, fax machine, copier, and a multi-functional machine. One example of an image forming device is Model No. C750 referenced above.
The term “imaging device” refers to a device that arranges an electrical charge on the photoconductive element 51. Various imaging devices may be used such as a laser printhead and a LED printhead.
A transport belt 20 is illustrated in the embodiments for moving the media sheets past the image forming units 100, and as part of the subunit. In another embodiment, roller pairs are mounted to the subunit 13 and spaced along the media path. The roller pairs move the media sheets past the image forming units 100. In one embodiment, each of the roller pairs is mounted on the subunit 13. In another embodiment, one of the rollers is mounted on the subunit, and the corresponding roller of the pair is mounted on the main body 12. In yet another embodiment, rollers may be positioned within the photoconductor unit 50.
The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. In one embodiment, both the photoconductive member 51 and the developer member 45 are cylindrically shaped. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
