Dual tray selectable sheet picking assembly

An imaging apparatus includes a printhead carrier system including a printhead carrier configured for movement along a scan path, a first sheet picking mechanism, a second sheet picking mechanism, and a selector device. The selector device is configured to select one of the first sheet picking mechanism and the second sheet picking mechanism for picking a sheet of print media based on a position of the printhead carrier.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging apparatus, and, more particularly, to a dual tray selectable sheet picking assembly.

2. Description of the Related Art

An imaging apparatus, such as an ink jet printer, may include multiple print media sources, such as for example, two paper trays. In one configuration of an imaging apparatus having two media sources, a single sheet picking mechanism is rotatable between two positions. In a first position, the picking mechanism has its pick rolls rotate in one direction to pick the top sheet of a first source of media. In a second position, the picking mechanism has its pick rolls rotate in the opposite direction to pick the bottom sheet of a second source of media. Such an approach, however, necessitates that the sheet picking mechanism be positioned between the two print media sources.

In another configuration, the imaging apparatus having multiple print media sources includes an independent sheet picking unit for each of the multiple print media sources. For example, if the imaging apparatus has two print media sources, the apparatus includes two sheet picking units and, in turn, two drive motors and two drive shafts. Such an approach, however, increases the complexity and cost of the imaging apparatus each time an additional sheet picking unit is added.

What is needed is the art is a sheet picking mechanism that accommodates sheet picking from multiple media sources using independent pick rollers, without needing multiple sheet picking motors and multiple pick drive shafts.

SUMMARY OF THE INVENTION

The present invention provides a sheet picking mechanism that accommodates sheet picking from multiple media sources using independent pick rollers, without needing multiple sheet picking motors and multiple pick drive shafts.

The present invention, in one form thereof, relates to an imaging apparatus. The imaging apparatus includes a printhead carrier system including a printhead carrier configured for movement along a scan path, a first sheet picking mechanism, a second sheet picking mechanism, and a selector device. The selector device is configured to select one of the first sheet picking mechanism and the second sheet picking mechanism for picking a sheet of print media based on a position of the printhead carrier.

In another form thereof, the present invention relates to a sheet picking device for an imaging apparatus. The sheet picking device includes a first sheet picking mechanism and a second sheet picking mechanism. A drive shaft is provided having a first section, a second section, and a third section located between the first section and the second section. The third section includes a spline. The first sheet picking mechanism includes a first drive gear rotatably coupled to the first section of the drive shaft. The first drive gear includes a first driven member. The second sheet picking mechanism includes a second drive gear rotatably coupled to the second section of the drive shaft. The second drive gear includes a second driven member. An engagement sleeve includes a bore for receiving the drive shaft. The bore has a spline channel that is configured to slidably receive the spline of the third section of the drive shaft. The engagement sleeve has a first end, a second end and an intermediate portion located between the first end and the second end. The first end has a first drive member for selectably engaging the first driven member of the first drive gear. The second end has a second drive member for selectably engaging the second driven member of the second drive gear. A selector linkage is coupled to the engagement sleeve. The selector linkage is configured to slide the engagement sleeve along an axis of the drive shaft to selectively position the engagement sleeve in engagement with one of the first driven member of the first drive gear and the second driven member of the second drive gear.

An advantage of the present invention is that sheet picking from multiple media sources is accommodated using independent pick rollers, without needing multiple sheet picking motors and multiple pick drive shafts.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and particularly toFIG. 1, there is shown an imaging system10embodying the present invention. Imaging system10may include a host12, or alternatively, imaging system10may be a standalone system.

Imaging system10includes an imaging apparatus14, which may be in the form of an ink jet printer14as shown. Thus, for example, ink jet printer14may be a conventional ink jet printer, or may form the print engine for a multi-function apparatus, such as for example, a standalone unit that has faxing and copying capability, in addition to printing.

Host12, which may be optional, may be communicatively coupled to imaging apparatus14via a communications link16. Communications link16may be, for example, a direct electrical connection, a wireless connection, or a network connection.

In embodiments including host12, host12may be, for example, a personal computer including a display device, an input device (e.g., keyboard), a processor, input/output (I/O) interfaces, memory, such as RAM, ROM, NVRAM, and a mass data storage device, such as a hard drive, CD-ROM and/or DVD units. During operation, host12includes in its memory a software program including program instructions that function as a printer driver for imaging apparatus14. The printer driver is in communication with imaging apparatus14via communications link16. The printer driver, for example, includes a halftoning unit and a data formatter that places print data and print commands in a format that can be recognized by imaging apparatus14. In a network environment, communications between host12and imaging apparatus14may be facilitated via a standard communication protocol, such as the Network Printer Alliance Protocol (NPAP).

Imaging apparatus14includes a printing mechanism18, a print media source20, and a mid-frame22. Printing mechanism18, when in the form of an ink jet printer, includes a printhead carrier system24and a feed roller unit26, as well as a controller28. Print media source20includes a primary media tray30for holding a primary print media32, and a secondary (or auxiliary) media tray34for holding a secondary print media36.

A sheet picking assembly37provides selectable sheet picking from one of primary media tray30and secondary media tray34. Sheet picking assembly37includes a primary sheet picking mechanism38, a secondary sheet picking mechanism40, and a sheet picking mechanism selector device42.

Primary sheet picking mechanism38includes a sheet picking roller39, and is positioned to pick a sheet of primary print media32from primary media tray30. Secondary sheet picking mechanism40includes a sheet picking roller41, and is positioned to pick a sheet of secondary print media36from secondary media tray34. Sheet picking mechanism selector device42provides for the selectable actuation of one of primary sheet picking mechanism38and secondary sheet picking mechanism40.

A picked media sheet44(i.e, a media sheet from one of primary print media32and secondary print media36) is transported to feed roller unit26, which in turn further transports media sheet44during a printing operation over mid-frame22, which provides support for media sheet44during the printing operation. The picked media sheet44may be, for example, plain paper, coated paper, photo paper, transparency media or envelopes, of various sizes, depending on from which of media trays30,34that media sheet44was picked. For example, primary media tray30may contain A4 sized plain paper as primary print media32, and secondary media tray34may contain envelopes as secondary print media36.

Printhead carrier system24includes a printhead carrier45for mounting and carrying a printhead46, e.g., a color printhead, and/or a printhead48, e.g., a monochrome or photo color printhead. An ink reservoir50, which may include color inks, is provided in fluid communication with printhead46. An ink reservoir52, which may include a monochrome ink or photo color inks, is provided in fluid communication with printhead48. Those skilled in the art will recognize that printhead46and ink reservoir50may be formed as individual discrete units, or may be combined as an integral unitary printhead cartridge. Likewise, printhead48and ink reservoir52may be formed as individual discrete units, or may be combined as an integral unitary printhead cartridge.

Printhead carrier45is guided by a pair of guide members54,56, such as for example, guide rods, which generally define a bi-directional scanning path58for printhead carrier45. Printhead carrier45is connected to a carrier transport belt60via a carrier drive attachment device62. Carrier transport belt60is driven by a carrier motor64via a carrier pulley66.

At the directive of controller28, printhead carrier45is transported in a reciprocating manner along guide members54,56. Carrier motor64can be, for example, a direct current (DC) motor or a stepper motor.

Feed roller unit26includes, for example, a feed roller68, pinch rollers (not shown) and a drive unit70. Feed roller68is driven by drive unit70. The pinch rollers apply a biasing force to hold the media sheet44in contact with respective driven feed roller68. Drive unit70includes a drive source, such as for example a direct current (DC) motor, and an associated drive mechanism, such as a gear train or belt/pulley arrangement. Feed roller unit26feeds the media sheet44, received from print media source20, in a sheet feed direction72designated as an X in a circle inFIG. 1to indicate that the sheet feed direction is out of the plane ofFIG. 1toward the reader. The sheet feed direction72is commonly referred to as the vertical direction, which is perpendicular to the horizontal bi-directional scanning path58. Thus, with respect to media sheet44, carrier reciprocation occurs in a horizontal direction and media advance occurs in a vertical direction, and the carrier reciprocation is generally perpendicular to the media advance.

Controller28is electrically connected and communicatively coupled to printheads46,48via a communications link74, such as for example a printhead interface cable. Controller28is electrically connected and communicatively coupled to carrier motor64via a communications link76, such as for example an interface cable. Controller28is electrically connected and communicatively coupled to drive unit70via a communications link78, such as for example an interface cable.

Controller28may be formed as an application specific integrated circuit (ASIC), and includes processing capability, which may be in the form of a microprocessor having an associated random access memory (RAM) and read only memory (ROM). Controller28executes program instructions to effect the printing of an image on media sheet44, such as for example, by selecting the index feed distance of print media sheet44as conveyed by feed roller68, controlling the reciprocation of printhead carrier45, and controlling the operations of printheads46,48. In addition, controller28executes instructions to effect the timely picking of print media from print media source20, using one of primary sheet picking mechanism38and secondary sheet picking mechanism40.

Each of primary sheet picking mechanism38and secondary sheet picking mechanism40receives its motive force from drive unit70. For example, drive unit70may be coupled via a transmission device80(represented by a dashed line), such as by a belt or gear train, to a sheet pick drive unit82. In turn, sheet pick drive unit82is coupled to a sheet pick drive shaft84. Sheet pick drive shaft84supports a pivoting arm86of primary sheet picking mechanism38and supports a pivoting arm88of secondary sheet picking mechanism40. Sheet picking mechanism selector device42then selectively transmits the motive force to one of primary sheet picking mechanism38and secondary sheet picking mechanism40.

Alternatively, sheet pick drive unit82may include a motor, separate from feed roller drive unit70, which is used as a power source for selectively driving one of primary sheet picking mechanism38and secondary sheet picking mechanism40via sheet picking mechanism selector device42.

Thus, in accordance with the present invention, one of primary sheet picking mechanism38and secondary sheet picking mechanism40is selected for media picking by sheet picking mechanism selector device42. In the example shown inFIG. 1, a spring assembly90, such as a coil spring and associated mounting structure, is positioned to apply a biasing force in direction92to sheet picking mechanism selector device42to provide a default engagement of sheet pick drive shaft84with primary sheet picking mechanism38. However, with the orientation of components as shown inFIG. 1, by shifting printhead carrier45to the far-right, printhead carrier45will engage a portion of a selector linkage94, thereby overcoming the biasing effect of spring assembly90, and shifting sheet picking mechanism selector device42in direction96to disengage sheet pick drive shaft84from primary sheet picking mechanism38, and to engage sheet pick drive shaft84with secondary sheet picking mechanism40.

Those skilled in the art will recognize that the selector linkage94may be configured as a straight linkage, as shown inFIG. 2, or as a pivoting linkage, as shown inFIG. 3, depending on the particular arrangement of components in imaging apparatus14.

FIG. 2shows a rear view, with respect toFIG. 1, of an embodiment of sheet picking assembly37, including primary sheet picking mechanism38, secondary sheet picking mechanism40and sheet picking mechanism selector device42.

Primary sheet picking mechanism38contains within pivot arm86(seeFIG. 1) a pick roller gear100, an intermediate gear102and a drive gear104. Pick roller gear100is connected to sheet picking roller39. A circumferential surface of each of pick roller gear100, intermediate gear102and drive gear104may include a plurality of teeth (not shown) for transferring rotary motion from drive gear104to intermediate gear102, and in turn, to pick roller gear100.

Drive gear104has a side surface106facing sheet picking mechanism selector device42. Side surface106includes a driven member108in the form of a plurality of teeth. Each of teeth of driven member108includes a drive surface110and a ramped surface112. Drive surface110provides positive engagement with the corresponding teeth of sheet picking mechanism selector device42, and ramped surface112facilitates initial engagement of sheet picking mechanism selector device42with driven member108of drive gear104.

Secondary sheet picking mechanism40contains within pivot arm88(seeFIG. 1) a pick roller gear120, an intermediate gear122and a drive gear124. Pick roller gear120is connected to sheet picking roller41. A circumferential surface of each of pick roller gear120, intermediate gear122and drive gear124may include a plurality of teeth (not shown) for transferring rotary motion from drive gear124to intermediate gear122, and in turn, to pick roller gear120.

Drive gear124has a side surface126facing sheet picking mechanism selector device42. Side surface126includes a driven member128in the form of a plurality of teeth. Each of teeth of driven member128includes a drive surface130and a ramped surface132. Drive surface130provides positive engagement with the corresponding teeth of sheet picking mechanism selector device42, and ramped surface132facilitates initial engagement of sheet picking mechanism selector device42with driven member128of drive gear124.

Within sheet picking assembly37, sheet pick drive shaft84includes a first section136, a second section138, and an intermediate section140located between first section136and second section138. Intermediate section140includes at least one spline142. Drive gear104is rotatably coupled to first section136of sheet pick drive shaft84, and may be retrained along directions92,96, for example, by snap rings (not shown). Drive gear124is rotatably coupled to second section138of sheet pick drive shaft84, and also may be retrained along directions92,96, for example, by snap rings (not shown). Sheet pick drive shaft84is rotatable, for example, in the direction indicated by arrow143.

In the embodiment of the present invention shown inFIGS. 1 and 2, sheet picking mechanism selector device42includes an engagement sleeve144and an extension member145. Engagement sleeve144includes a bore146having a spline channel148. Spline channel148is configured to slidably receive spline142of intermediate section140of sheet pick drive shaft84.

Engagement sleeve144has a first end portion150, a second end portion152and an intermediate portion154located between first end portion150and said second end portion152. First end portion150has a drive member156in the form of a plurality of teeth configured to be complimentary to the teeth of driven member108. Drive member156is positioned to selectably engage driven member108of drive gear104. Second end portion152has a drive member158in the form of a plurality of teeth configured to be complimentary to the teeth of driven member128. Drive member158is positioned to selectably engage driven member128of drive gear124.

Extension member145is coupled to intermediate portion154of engagement sleeve144. Extension member145provides an offset attachment point for coupling selector linkage94to engagement sleeve144. Selector linkage94is configured to slide engagement sleeve144along an axis160of sheet pick drive shaft84to selectively position engagement sleeve144in driving engagement with one of first drive gear104and second drive gear124.

Thus, depending on the selection made by sheet picking mechanism selector device42, via the position of printhead carrier45, sheet pick drive shaft84may be selectively coupled via engagement sleeve144to one of drive gear104located in pivoting arm86so as to apply a rotational force to sheet picking roller39, or selectively coupled to drive gear124located in pivoting arm88so as to apply a rotational force to sheet picking roller41.

For example, with the orientation of components as shown inFIGS. 1 and 2, by shifting printhead carrier45in direction96to the far-right inFIG. 1, printhead carrier45will engage a portion of selector linkage94. In turn, when using the straight linkage configuration ofFIG. 2(i.e., extension member145does not pivot), sheet picking mechanism selector device42, including engagement sleeve144, will shift in direction96to thereby selectively couple sheet pick drive shaft84to drive gear124located in pivoting arm88, so as to apply a rotational force to sheet picking roller41, and in turn, to pick secondary print media36from secondary media tray34.

Upon shifting printhead carrier45in direction92, spring assembly90will bias sheet picking mechanism selector device42in direction92to thereby selectively couple sheet pick drive shaft84to drive gear104located in pivoting arm86, so as to apply a rotational force to sheet picking roller39, to pick primary print media32from primary media tray30. In other words, sheet picking mechanism selector device42will be returned to its default position to pick from primary media tray30as printhead carrier45moves away from the far-right position inFIG. 1.

FIG. 3shows a rear view of another embodiment of the present invention, which replaces sheet picking mechanism selector device42, including the straight linkage formed by extension member145and engagement sleeve144, with a sheet picking mechanism selector device242, including an engagement sleeve244and a pivoting linkage245.

The arrangement ofFIG. 3effectively provides a reversal of the selective driving of one of sheet picking roller39and sheet picking roller41from that described above with respect toFIG. 2. As such, the location of selector linkage94is reversed with respect to the configuration shown inFIG. 1, such that printhead carrier45would engage selector linkage94with a far-leftward movement, with respect toFIG. 1, of printhead carrier45in direction92.

In the embodiment of the present invention shown inFIG. 3, engagement sleeve244includes a bore246, an annular recess247, and at least one spline channel248located along bore246. Each spline channel248is configured to slidably receive a corresponding spline142of intermediate section140of sheet pick drive shaft84. Pivoting linkage245includes a yoke249that engages annular recess247in engagement sleeve244. Yoke249is configured to slide engagement sleeve244along an axis160of sheet pick drive shaft84to selectively position engagement sleeve244in driving engagement with one of first drive gear104and second drive gear124as pivot linkage245pivots in one of pivot directions251.

Engagement sleeve244has a first end portion250, a second end portion252and an intermediate portion254located between first end portion250and said second end portion252. First end portion250has a drive member256in the form of a plurality of teeth configured to be complementary to the teeth of driven member108. Drive member256is positioned to selectably engage driven member108of drive gear104. Second end portion252has a drive member258in the form of a plurality of teeth configured to be complementary to the teeth of driven member128. Drive member258is positioned to selectably engage driven member128of drive gear124.

Depending on the position of printhead carrier45, sheet pick drive shaft84may be selectively coupled via engagement sleeve244to one of a drive gear104located in pivoting arm86so as to apply a rotational force to sheet picking roller39, or selectively coupled to a drive gear124located in pivoting arm88so as to apply a rotational force to sheet picking roller41.

Selector linkage94is connected to pivot linkage245. Pivot linkage245pivots about a pivot member259, such as for example, when acted upon by selector linkage94.

With the orientation of components as shown inFIG. 3, by shifting printhead carrier45in direction92, printhead carrier45will engage a portion of selector linkage94. In turn, when using the pivot linkage245configuration ofFIG. 3, engagement sleeve244of sheet picking mechanism selector device242will shift in direction96to thereby selectively couple sheet pick drive shaft84to drive gear124located in pivoting arm88, so as to apply a rotational force to sheet picking roller41, and in turn, to pick secondary print media36from secondary media tray34.

Upon shifting printhead carrier45in direction96, spring assembly90(as inFIG. 1) will bias engagement sleeve244of sheet picking mechanism selector device242in direction92to thereby selectively couple sheet pick drive shaft84to drive gear104located in pivoting arm86, so as to apply a rotational force to sheet picking roller39, to pick primary print media32from primary media tray30. In other words, sheet picking mechanism selector device242will be returned to its default position to pick from primary media tray30.