Patent Application
20090020940
Some electronic devices, such as printers, copiers and scanners, feed sheets of media from a stack of media. The number of sheets of media or stacking height of the media is limited in many of these electronic devices.
Exemplary embodiments are directed to apparatus, systems, and methods for feeding and transporting media. An articulating sheet feed apparatus has improved pick reliability. In one embodiment, a pick arm pivotally connects to an articulating mount pick arm that is movable with respect to a stack of media. The mount pick arm moves to accommodate different thicknesses of the stacked media. The mount pick arm includes one or more spacer wheels that are registration points for a top sheet of media to ensure a consistent pick geometry throughout a full height of the media stack. As media is picked from the stack, the mount pick arm advances toward the media so the pick arm maintains a consistent distance for picking each successive piece of media.
In one embodiment, a mount pick arm lock prevents the mount pick arm from moving away from the media. By way of example, the pick arm lock is actuated from a rocker gear that engages a sheet feed mechanism. Locking of the mount pick arm occurs when the electronic device is instructed to pick a new sheet of media. The rocker gear engages and causes die pick arm lock to operate.
Sheet feed apparatus 25 feeds individual sheets 14 of media from a stack 16 in a tray 12 to electronic device 10. Sheet feed apparatus 25 includes floor 20 and sheet pick device or pick arm 24, and the tray 12 includes a backrest 22.
Floor 20 comprises a member supported below backrest 22 and is configured to provide a surface 26 against which edges 28 of sheets 14 rest. In the particular example shown, floor 20 further provides a transition surface 30 angled with respect to surface 26 such that movement of edge 28 of a sheet 14 along surfaces 26 and 30 results in the sheet of media being reoriented. Surface 26 is substantially smooth and has a low coefficient of friction such that edges 28 of sheets 14 are less likely to be damaged when being picked by pick arm 24. At the same time, however, due to the geometry of the components of sheet feed apparatus 25, individual sheets 14 can be reliably separated and picked from slack 16 in tray 12 by the pick arm 24.
Backrest 22 comprises one or more members configured to support stack 16 upon floor 20 in an inclined orientation. In particular, backrest 22 is configured to bear against and support a rear face 32 or rearward most sheet 14 of stack 16. Backrest 22 includes one or more surfaces 36 that contact face 32 and generally extend in a common linear plane 38. Plane 38 intersects plane 40 in which surface 26 extends. Planes 38 and 40 are angularly spaced such that pick device 24 may pick and separate individual sheets 14 from stack 16.
As further shown by
Pick arm 24 comprises a device configured to engage a front face 44 of a frontward-most sheet 14 of stack 16 so as to urge stack 16 against backrest 22. Pick arm 24 is also configured to move or drive the frontward-most sheet 14 in a direction generally parallel to plane 38 such that edge 28 of a frontward-most sheet 14 moves along surfaces 26 and 30 into device 10. In the particular example shown, pick arm 24 includes a rotatably driven cylinder or pick tire 46 that provides a media driving surface 48 that contacts face 44. In particular, face 44 and the frontward-most sheet 14 of stack 16 generally extend in a plane 50 that is substantially parallel to plane 38. Media driving surface 48 contacts face 44 at a location within plane 50 that is spaced from an intersection of plane 50 and plane 40 by a distance such that media driving surface 48 applies a force to face 44 so as to pick and separate the frontward-most sheet 14 of stack 16 from the remaining sheets 14 of stack 16.
Although media driving surface 48 is illustrated as being provided by a cylindrical drive member or roller 46, media driving surface 48 can alternatively be provided by other members and mechanisms. For example, media drive surface 48 can be provided by multiple rollers that are coaxial or axially spaced from one another. In still other embodiments, media driving surface 48 is provided by belts or other endless members that rotate about multiple axes and that contact face 44 of the frontward-most sheet 14 of stack 16.
As further shown by
In the particular example shown in
Media transport 62 comprises a mechanism that engages and drives sheets 14 of media along media path 70 relative to image-forming device 64 and out discharge opening 72. Media transport 62 receives an individual sheet 14 picked by pick device 24 and drives the individual sheet 14 as shown in phantom in
Image-forming device 64 comprises a device configured to form an image, such as text, a photograph and the like, upon at least one lace of an individual sheet 14. In the particular example shown, image-forming device 64 includes one or more printheads that deposit ink upon a sheet 14. The one or more printheads can be stationarily supported, such as in a page-wide array printhead or can be movably supported by a carriage (not shown). In still other embodiments, other image-forming devices can be employed such as electro-photographic printing devices that utilize one or more electrically charged surfaces to apply dry or liquid toner to a surface of a sheet 14 of media or such as dye sublimination printers and the like.
Actuator 66, schematically shown, comprises a device that drives the sheet feed apparatus 25 (see
Controller 68 comprises a processing unit that generates control signals for directing actuator 66 and image-forming device 64. For purposes of this disclosure, the term “processing unit” means a conventionally known or future developed processing unit that executes sequences of instructions contained in a memory. Execution of the sequences of instructions causes the processing unit to perform steps such as generating control signals. The instructions can be loaded in a random access memory (RAM) for execution by the processing unit from a read only memory (ROM), a mass storage device, or some other persistent storage. In other embodiments, hard wired circuitry can be used in place of or in combination with software instructions to implement the functions described. Controller 68 is not limited to any specific combination of hardware circuitry and software, nor to any particular source for the instructions executed by the processing unit.
In operation, controller 68 generates control signals that direct actuator 66 to drive sheet feed apparatus 25 (including the media drive member 46 and the mount pick arm) so as to pick an individual sheet 14 from stack 16. Media driving member 46 is rotatably driven until edge 28 of the frontward-most sheet 14 is engaged by media transport 62. Controller 68 further generates control signals directing actuator 66 to drive media transport 62 so as to move the picked sheet 14 of media relative to image-forming device 64. Controller 68 generates control signals directing image-forming device 64 to print or otherwise form an image upon face 44 of sheet 14. Thereafter, the printed-upon sheet 14 is discharged through discharge opening 72.
The mount pick arm 104 includes a generally rectangular or square body 120 with two oppositely disposed and parallel arms 122. The arms 122 extend outwardly from the body 120 and rotatably or pivotally attach to a body of the electronic device at an axis 126. The body is able to rotate about axis 126 in order to move pick arm 24 towards and away from the stack of media. The media box 100 includes a curved opening 128 through which a portion of the mount pick arm 104 travels.
The mount pick arm 104 includes one or more spacer wheels 130 that rotate about axis 56. The spacer wheels are spaced apart with the pick arm 24 disposed between the two wheels. In one embodiment, the spacer wheels 130 rest on a top sheet of media. As the stack of media moves, the mount pick arm 104 simultaneously moves or follows the stack of media. For example during a print operation, as sheets of media are removed from the media box 100, the mount pick arm 104 moves toward an inner tray 132 of tray 12. By contrast, as sheets of media are added to the media box 100, the mount pick arm moves away from the inner tray 132.
In one embodiment, the mount pick arm 104 moves between a first or extended position and a second or retracted position. In the first position, the mount pick arm 104 is adjacent the inner tray 132 such that the spacer wheels 130 abut an outer surface 136 of the inner tray 132 (example, when the media box 100 does not include any media). In the second position, the mount pick arm 104 is displaced away from the outer surface 136 of the inner tray 132. For example,
The sheet feed apparatus 25 can be configured to accommodate a wide range media stack heights. By way of example,
In one exemplary embodiment, the spacer wheels 130 contact the outer piece of media (i.e., farthest from the inner tray 132) and provide a registration point for the top sheet of media. As such, the spacers wheels assist in providing a consistent pick geometry throughout a full height of the stack of media. By way of example, as media is picked from the stack, the mount pick arm 104 advances toward the inner tray 132. The angle of the pick arm 24 with respect to the media remains consistent or constant while successive pieces of media are picked and removed from the stack of media. In this manner, the sheet feed apparatus 25 picks each media with a consistent force. For instance, the pick tire 46 engages each piece of media in a stack with a consistent force and geometry (example, angle of engagement) since the mount pick arm and pick arm move toward the media. In one embodiment, the mount pick arm 104 advances or moves an amount equal to a thickness of the picked media.
The pick arm assembly 102 includes two separate components (the pick arm 24 and the mount pick arm 104) that articulate with respect to each other at two different and separate pivot locations. A first pivot location occurs along axis 56 for one end of the pick arm 24, and a second pivot location occurs along axis 126 for each end of arms 122. As such, the pick arm 24 is connected to and travels with the mount pick arm 104. The two piece configuration of the pick arm assembly 102 enables the pick arm 24 to move, swing, or rotate through a larger radius (example as opposed to a pick arm that is stationary with respect to the mount pick arm). The mount pick arm 104 follows a thickness of the media stack using the sheet feed gear system 110. Thus, an angel of the mount pick arm 104 with respect to the inner tray 132 varies. Further, because the mount pick arm 104 is pivotally supported about axis 126, pick arm 24 accommodates different stacks of media having different overall thicknesses.
When the electronic device initiates a pick of media, a locking system locks the mount pick arm and prevents it from moving. By way of example, the locking plate 170 moves upwardly to move the mount pick arm lock 108 to engage teeth 190 formed in the body of the media box 100. By way of example, one end of the mount pick arm lock 108 includes an end 200 shaped and sized to fit between adjacent teeth 190 and prevent the mount pick arm 104 from moving. In this manner, the mount pick arm 104 remains stationary during a pick of media from the media stack. As such, a position of the pick arm 24 remains stable during media pick and transportation.
In one embodiment, the mount pick arm lock 108 is directly actuated from the rocker gear 180 that engages the sheet feed mechanism. This configuration overcomes any specific timing issues by ensuring the pick does not occur before the mount pick arm 104 is in the fixed position. In other words, the rocker gear engages to lock the pick arm in a stable position during media transportation at the instant in time when the sheet feed gear train is actuated. When the sheet feed gear train is engaged, the sheet feed apparatus 25 simultaneously locks the position of the mounting pick arm 104 and pick arm 24.
Although sheet feed apparatus 25 has been illustrated as being utilized as part of an electronic device 10 comprising a printer, sheet feed apparatus 25 can also be utilized in other electronic devices that manipulate or alter a sheet of media. For example, sheet feed apparatus 25 can also be used to feed individual sheets of media that are already have an image, wherein the electronic device scans or reads the image upon the sheet of media. In other applications, sheet feed apparatus 25 is utilized in an electronic device that is configured to cut, fold or otherwise alter the characteristics of the sheet 14 of media. In some embodiments, sheet feed apparatus 25 is provided as part of a module that is releasably connected to an electronic device.
The above discussion is meant to be illustrative of the principles and various embodiments. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
