Patent Application
20060157911
Many electronic devices, such as printers, copiers and scanners, feed sheets of media from a stack of media. In an attempt to feed one sheet of media at a time, many devices include a rubber separator pad that applies friction to the edge of the stack. This separator pad may damage the edge of the media, may involve low manufacturing and assembly tolerances and may increase the number of parts, complexity and cost of the sheet feeding mechanism.
Sheet feed apparatus 12 feeds individual sheets 14 of media from a stack 16 to device 10. Sheet feed apparatus 12 generally includes floor 20, backrest 22 and sheet pick device 24. 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 device 24. At the same time, however, due to the geometry of the components of sheet feed apparatus 12, individual sheets 14 may be reliably separated and picked from stack 16 by pick device 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 which 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. In the example shown, planes 38 and 40 are angularly spaced by at least 108 degrees and no less than 116 degrees.
As further shown by
Pick device 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 device 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 device 24 includes a rotatably driven cylinder 46, sometimes referred to as a pick tire, which provides a media driving surface 48 which 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 may apply 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. In the particular example shown, media driving surface 48 contacts face 44 at a location spaced from the intersection of plane 50 and plane 40 by a distance less than or equal to 31 millimeters. For accommodating relatively flexible print media such as 8.5 inch by 11 inch multi-purpose office paper having a weight of approximately 75 g/m2, wherein 500 sheets weighs approximately 20 pounds, media driving surface 48 is spaced from the intersection of planes 40 and 50, within plane 50, and generally perpendicular to edge 28 by a distance of less than or equal to 25 millimeters. To accommodate both relatively flexible print media and relatively stiffer media such as photo paper, postcards and the like, media driving surface 48 is located so as to contact face 44 at a location spaced from the intersection of planes 40 and 50 by a distance less than or equal to 30 millimeters.
Although media driving surface 48 is illustrated as being provided by a cylindrical drive member or roller 46, media driving surface 48 may alternatively be provided by other members and mechanisms. For example, media drive surface 48 may be provided by multiple rollers which are coaxial or axially spaced from one another. In still other embodiments, media driving surface 48 may be provided by belts or other endless members which rotate about multiple axes and which contact face 44 of the frontward-most sheet 14 of stack 16.
As further shown by
Overall, sheet feed apparatus 12 enables individual sheets 14 to be separated or picked from a stack 16 with reduced damage to edges 28 of such sheets 14. The geometry of sheet feed apparatus 12 reduces or eliminates the need for an additional rubber separator pad. As a result, some embodiments of sheet feed apparatus 12 may employ fewer parts, and may be less expensive to manufacture and/or easier to assemble.
In the particular example shown in
Media transport 62 comprises a mechanism configured to engage and drive 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 face of an individual sheet 14. In the particular example shown, image-forming device 64 may include one or more printheads configured to deposit ink upon a sheet 14. The one or more printheads may be stationarily supported, such as in a page-wide array printhead or may be movably supported by a carriage (not shown). In still other embodiments, other image-forming devices may be employed such as electro-photographic printing devices which 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 configured to drive pick member 46, media transport 62 and a carriage (not shown) of image-forming device 64. In one embodiment, actuator 66 comprises one or more electrically powered motors operably coupled to media drive member 46, media transport 62 and image-forming device 64 via power trains 76, 78 and 80, respectively. Power trains 76, 78 and 80 may include one or more gears, pulleys, belts, chains, sprockets and the like by which mechanical power may be transmitted from actuator 66. In other embodiments, actuator 66 may utilize other electrical, pneumatic, hydraulic actuators for providing mechanical power to drive member 46, transport 62 or device 64.
Controller 68 comprises a processing unit configured to generate control signals for directing actuator 66 and image-forming device 64. For purposes of this disclosure, the term “processing unit” shall mean 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 may 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 may 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 media driving member 46 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.
Although sheet feed apparatus 12 has been illustrated as being utilized as part of an electronic device 10 comprising a printer, sheet feed apparatus 12 may also be utilized in other electronic devices configured to manipulate or alter a sheet of media. For example, sheet feed apparatus 12 may also be used to feed individual sheets of media which may already have an image, wherein the electronic device is configured to scan or read the image upon the sheet of media. In other applications, sheet feed apparatus 12 may be utilized in an electronic device which is configured to cut, fold or otherwise alter the characteristics of the sheet 14 of media. In some embodiments, sheet feed apparatus 12 may be provided as part of a module which is releasably connected to an electronic device.
In the particular example shown, surface 126 is provided by a plurality of individual landings 160a, 160b, 160c, 160d and 160e. Landings 160a-160e are transversely spaced from one another to reduce the amount of material used for floor member 120 and to reduce the amount of energy used to drive media pick device 124 to move a sheet 14 along surface 126. At the same time, landings 160a-160e are appropriately located with respect to one another to enable floor member 120 to accommodate differently dimensioned media and to minimize or prevent potential damage to edges 28 of sheets 14 of media by distributing force of the sheet along the surface of each landing 160a-160e. In the particular example shown, each landing 160a-160e has a minimum transverse width of at least 5 mm to minimize or prevent damage to edges 28 of sheets 14 of media. In the particular example shown, landing 160a has a width of 9.4 mm, landing 160b has a width of 15.4 mm, landing 160c has a width of 5.9 mm, landing 160d has a width of 9.4 mm and landing 160e has a width of 9.4 mm. Landings 160a-160e are spaced from one another so as to span across and engage a large portion of each edge 28 of each sheet 14 and to support those portions of sheets 14 most susceptible to curling. In the particular example shown, landing 160a is spaced from a media edge datum provided by sidewall 190 by approximately 3.3 mm. Adjacent edges of landings 160a and 160b are spaced from one another by 30.5 mm, adjacent edges of landings 160b and 160c are spaced apart from one another by 7.6 mm, adjacent edges of landings 160c and 160d are spaced apart from one another by 7.6 mm, and adjacent edges of landings 160d and 160e are spaced apart from one another by 15.6 mm. As a result, surface 126 provided by landings 160a-160e is arranged such that surface 126 contacts opposite portions of edges 28 and sheets 14 regardless of whether sheet 14 has an overall width of 8.5 inches by 11 inches, four inches by 6.0 inches or other media types such as A6 media. Landing 160c, which is transversely spaced from media edge datum 190 by approximately 56.8 mm is configured to support edge 28 of sheets 14 of the 4 by 6 or by A6 media at a location which has been found to be most susceptible to curling in low humidity (20% humidity) environments. In other embodiments, floor member 120 may alternatively include a greater or fewer number of such landings. In other embodiments, in lieu of including multiple spaced-apart landings, floor member 120 may include a single continuous transverse floor surface that abuts edge 28 of one or more sheets 14.
Surface 130 extend from surfaces 126 generally at an angle distinct from that of surface 126. Surface 130 is similar to surface 30 shown and described with respect to
As further shown by
Media position sensor 166 comprises a sensor configured to detect the presence or absence of a sheet 14 of the media. This information is transmitted to a processor or controller for generating control signals directing the operation of pick device 124. In the particular example shown, sensor 166 comprises one or more flags projecting above surface 130 and configured to be tripped by movement of edge 28 of a sheet 14 of media.
Backrest 122 is similar to backrest 22 in that backrest 122 is configured to support a stack 16 of sheets 14 in an inclined orientation. In particular, backrest 122 is configured to support stack 16 along a plane 150 that intersects plane 140 and that is angularly spaced from plane 140 so as to enable pick device 124 to pick and separate an individual frontward-most sheet 14 from stack 16. Plane 150 is angularly spaced from plane 140 along which surface 26 extends by an angle A1. In the particular example shown, angle A1 is between 108 degrees and 116 degrees. In the particular example shown, plane 140 is angularly spaced from the horizontal by approximately 10 degrees while backrest 122 supports sheets 14 along plane 150 which is angularly spaced from the vertical by angle A2, approximately 12 degrees. Because plane 150 is angularly spaced from the vertical by at least 8 degrees, pick device 124 more easily drives a sheet 14 from stack 16 and the chance of the sheet 14 buckling backwards is reduced. Because plane 150 is angularly spaced from the vertical by 12 degrees, backrest 122 forms an opening configured to receive a stack 16 having a thickness of approximately 6.5 mm, equivalent to approximately 20 sheets of media, according to some embodiments. In other embodiments, plane 140 in which surface 126 extends and plane 150 in which sheets 14 are supported may have other positions with respect to the horizontal and vertical.
As shown by
Extension 172 comprises a structure movably supported relative to door 170 and configured to be extended and retained at one of a plurality of different lengths. Extension 172 enables feed apparatus 112 to accommodate sheets 14 having varying heights above surface 126.
Main media guide 174 comprises one or more structures coupled to door 170 and configured to provide one or more surfaces 136 against which face 32 of a rearward-most sheet 14 bear. Surfaces 136 generally extend in a common plane 138 substantially parallel to plane 50 along with sheets 14 are supported. In the particular example shown, surface 136 of guide 174 includes a compressible portion 186 extending generally opposite pick device 124. Portion 186 is compressible and has a relatively high coefficient of friction. Portion 186 cooperates with pick device 124 to facilitate picking of individual sheets 14 of the media when the total number of sheets 14 of stack 16 are reduced in number. In one embodiment, portion 186 is formed from a cork material.
Adjustable guides 182 and 184 assist in the input of media and the alignment of media with respect to floor 126. Adjustable guide 182 is pivotally supported for rotation about axis 188 extending generally perpendicular to plane 138. Adjustable guide 182 comprises a structure configured to engage the side edges of stack 16. In the example shown, adjustable guide 182 is resiliently biased by a resilient member such as one or more springs towards an opposite stationary datum or sidewall 190 of main guide 174 to urge stack 16 against sidewall 190.
Adjustable guide 184 comprises a projection extending from surface 136 and configured to also engage a side edge of stack 16 of sheets 14. Adjustable guide 184 comprises a structure that is slidable along a transverse axis 192. In the particular example shown, adjustable guides 184 are configured to be manually slide towards or away from sidewall 190. Although media feed apparatus 112 is illustrated as including extension 172 and adjustable guides 182,184, media feed apparatus 112 may alternatively omit such extensions and guides.
Pick device 124 is similar to pick device 24 shown and described with respect to
Mounting 194 and support 154 support pick roller 146 opposite backrest 122. Mounting 194 is coupled to backrest 122 and pivotally supports support 154 for pivotal movement about axis 198. Support 154 comprises an arm which extends from axis 198 to axis 196. Support 154 and pick roller 146 pivot towards and away from face 44 of frontward-most sheet 14 depending upon the overall thickness of stack 16. In one embodiment, support 154 is resiliently biased towards face 44 by a spring or other resilient member (not shown). In the particular example shown, axis 198 about which support 154 pivots is perpendicularly spaced from plane 138, established by surface 136, by a distance of between 12 millimeters and 20 millimeters. In the example shown, axis 198 is perpendicularly spaced from plane 138 by a distance D2 of about 18.6 millimeters. As a result, media feed apparatus 112 may accommodate a stack 16 of a substantial number of sheets 14 of the media.
As further shown by
Like media feed apparatus 12, media feed apparatus 112 enables individual sheets 14 to be separated and picked from stack 16 while minimizing potential damage to edges 28 of sheets 14 of media. At the same time, media feed apparatus 112 enables a relatively low friction floor surface 126 to be utilized without a high friction separator pad. As a result, media feed apparatus 112 may employ fewer parts, may be less expensive to manufacture and may be more easily assembled.
Although the present invention has been described with reference to example embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Further, the various dimensions, ratios, and other quantitative information is provided by way of example and is not limiting. In some embodiments, not all of the dimensions and ratios described will be present. For example, although different example embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example embodiments or in other alternative embodiments. Because the technology of the present invention is relatively complex, not all changes in the technology are foreseeable. The present invention described with reference to the example embodiments and set forth in the following claims is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the claims reciting a single particular element also encompass a plurality of such particular elements.
