Patent Application
20050207780
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 a door assembly on an image forming device. The door assembly is positionable between open and closed orientations to position a cartridge unit relative to a body of the device.
In one embodiment, the invention includes a first frame pivotally mounted to the body at a first pivot and positioned between open and closed orientations. A second frame is pivotally connected to the first frame at a second pivot. In an open orientation, the second frame is spaced from the body and moved relative to the first frame. In the closed orientation, the first frame is moved inward with the second frame being registered relative to the body.
In another embodiment, the device comprises a body with a developer member. A first frame is connected to the body at a first pivot with the first frame being positioned between a first orientation with a second end distanced from the body, and a second orientation with the second end in proximity to the body. A second frame having a photoconductive member is attached to the first frame at a second pivot. The second frame pivots separately from the first frame to position the photoconductive member in contact with the developer roll when the first frame is in the second orientation.
In another embodiment, a number of developer members are positioned within the body and a number of photoconductive members are positioned on the second frame. Each of the photoconductive members has substantially the same travel length as the first frame and second frame are moved from an intermediate orientation to a closed orientation.
Media sheets are moved from the input and fed into a primary media path. One or more registration rollers 99 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 51 within the image forming units 100. 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 direction to move the media sheet to an output tray 28, or rollers 26 rotate in a reverse direction to move the media sheet to 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.
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 along a developer nip 46 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 accurate placement of each of the developer unit 40 and photoconductor unit 50 is important for uniform contact pressure along the full axial extent of the developer nip 46.
As illustrated in
Door assembly 13 is movably attached relative to the main body 12 between an opened orientation as illustrated in
The door assembly 13 comprises a first frame 60 and a second frame 61 as illustrated in
The second frame 61 is pivotally attached to the first frame 60 at a second pivot 19. The second pivot 19 allows the second frame 61 to move relative to the first frame 60. Stops 62 extend from the first frame 60 to control the extent of movement of the second frame 61. The second frame 61 includes a first side 64 so the photoconductive members 51 face towards the main body 12 when the door assembly 13 is in the closed orientation. In the closed orientation, the second frame 61 is accurately aligned with the main body 12 such that the photoconductive members 51 are aligned with the developer rolls 45.
The second pivot 19 allows for relative movement between the second frame 61 and the first frame 60. The second frame 61 can move relative to the first frame 60 as the door assembly 13 moves between the open and closed orientations. The allowable motion between the first frame 60 and the second frame 61 is minimized radially at pivot 19 to maintain positional control of the second frame 61 and photoconductive members 51, but have enough allowable radial movement so as not to impart unwanted forces to the first side 64 when the door assembly 13 is in the closed orientation. Further, the second pivot 19 transmits a force applied from the first frame 60 to the second frame 61 when the door assembly 13 is moved between the open and closed orientations.
As illustrated in
The size, shape, and location of the contact surface 65 and the contour surface 70 may vary depending upon the application. In the embodiment illustrated in
In one embodiment illustrated in
Movement of the first and second frames 60, 61 from the open orientation to the intermediate orientation is rotational about the first pivot 14. The travel distance of a point on the door assembly 13 increases with the distance from the first pivot 14. Therefore, a first photoconductive member 51a mounted towards an upper edge of the second frame 61 has a greater travel distance than a second photoconductive member 51b mounted towards a lower edge.
In one embodiment, the door assembly 13 can be represented by a four-bar linkage when moving between the intermediate orientation and the closed orientation as illustrated in dashed lines in
R2 is the distance between the first pivot 14 and the second pivot 19. R1 is set equal to R2 and defined between the contour surface 70 and point A. The radius R2 defines the shape of the contour surface 70. Because R1 is a discrete length, the contour surface 70 has a curved configuration. As the second frame 61 moves from the intermediate orientation to the closed orientation, the contact surface 65 slides along the contour surface 70 and each of the photoconductive members 51 have substantially the same travel path, including substantially the same angle of approach towards the main body 12, and substantially the same travel distance. Therefore, photoconductive member 51a located most remotely from the first pivot 14 aligns and mates with its respective developer member 45 in the main body 12 in the same manner as photoconductive member 51b.
The travel path of the photoconductive members 51 is not completely horizontal because the contour surface 70 has a curved configuration (if R1 had an infinite length, contour surface 70 would be perfectly horizontal and the travel path would be completely horizontal). Therefore, the photoconductive members 51 have an angle of approach relative to the developer members 45. The highest vertical point may be positioned at any location between the inner and outer edge of the contour surface (i.e., anywhere between the intermediate and closed orientations).
The 4-bar linkage controls the approach of the photoconductive members 51 from the intermediate orientation to the closed orientation. In one embodiment, R1 is equal to R2, and links 102 and 104 are parallel during the range between the intermediate and closed orientations. The first side 64 stays substantially parallel to the face of the opening 18 where the developer members 45 are located. In one embodiment, the first side 64 is substantially vertical as the door assembly 13 moves from the intermediate to closed orientations, and the first pivot 14 is located vertically below the second pivot 19, and the photoconductive members 51a, 51b are vertically aligned.
When the door assembly 13 is opened beyond the intermediate orientation, the contact between the contact surface 65 moves from the contour surface 70 when 62b contacts 61 and the 4-bar linkage is broken. This motion includes the second frame 61 moving in rotational motion about the first pivot 14.
The contour surface 70 and contact surface 65 may have a variety of shapes and sizes. In another embodiment, the contour surface 70 is approximated to be similar to radius R2. Additionally, manufacturing tolerances may result in the contour surface 70 having a slightly different shape than that mathematically determined as R2. In one embodiment, the contour surface is within 5% of R2. In one embodiment, contour surface 70 is flat.
The term “image forming device” and the like is used generally herein as a device that produces images on a media sheet. 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 available from Lexmark International, Inc. of Lexington Ky.
Another embodiment of a two-piece cartridge and door assembly is disclosed in U.S. patent application Ser. No. ______ (Attorney Docket No. 4670-201) entitled “Movable Subunit and Two Piece Cartridge for Use in an Image Forming Device” filed concurrently herewith, assigned to Lexmark International, Inc., and incorporated herein by reference in its entirety.
The embodiments illustrate a transfer belt 20 used for moving the media sheets past the image forming units 100. In another embodiment, nip rollers are used for holding and propelling the media sheets. Various other forms of media movement devices may also be used in the present invention.
In one embodiment, the photoconductor unit 50 is attached to the door assembly 13 via a plurality of mounts. One embodiment of the structure on the door assembly and photoconductor unit is disclosed in U.S. patent application Ser. No. ______ (Attorney Docket No. 4670-272) entitled “Door Assembly for an Image Forming Device”, filed concurrently with the present application, and incorporated herein by reference in its entirety.
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, the upper stop is an over-travel stop that controls the extent of movement of the second frame 61 about the second pivot 19. During normal use, the second frame 61 does not contact the upper stop 62a. In one embodiment, the first side 64 is formed by the transport belt 20. 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.
