Media registration system with lateral registration

A media registration system including a track to transport media in a transport direction from an intake end to a registration end, and a pivot shaft. A translator to register media in a lateral direction to the transport direction includes a translation element operatively coupled to the track and moveable along a translation axis in the lateral direction, and a driver to drive the translation element a translation distance along the translation axis to rotate the track about the pivot shaft to move the registration end a selected registration distance in the lateral direction, the translation distance proportional to the selected registration distance.

BACKGROUND

Post-imaging operations for sheets of imaging media, such as from a printer, for instance, include aligning, stacking, and stapling sheets of media, for example.

DETAILED DESCRIPTION

Upon discharge from an image forming apparatus, such as a printer, for example, media conveying systems may perform various post-imaging operations such as aligning, stacking, and stapling sheets of imaging media, for example. Aligning and stacking of sheets of media may be sometimes be referred to as “registration”, with media output systems sometimes being referred to as media registration systems.

FIG. 1is a block and schematic diagram generally illustrating a top view of a media registration system30, according to one example of the present disclosure. Media registration system30includes a transport track32to receive sheets of media34at an intake end36, such as from an image forming apparatus (e.g., a printer), and to transport sheets of media34along transport track32in a transport direction33(illustrated as a y-direction inFIG. 1) to an output or registration end38.

In one example, media registration system30includes a translator40to rotate transport track32about a pivot42to a adjust a position of registration end38in a direction35lateral to transport direction33to provide registration or alignment of edges of sheets of media34in the lateral direction35at registration end38to form a media stack, such as for stapling operations, for example. In one example, lateral direction35is orthogonal to transport direction33(such as an x-direction inFIG. 1). In examples, as illustrated, pivot42enables rotation of transport track32in the x-y plane. In one case pivot42is a pivot shaft extending orthogonally to transport and lateral directions33and35, such as a z-direction (into/out of page inFIG. 1). In one example, pivot42is disposed proximate to intake end36. In one example, pivot42is disposed at a corner of transport track32at intake end36.

In one example, translator40includes a driver44and a translation element46operatively coupled to transport track32, where driver44drives translation element46to rotate transport track32about pivot42. According to examples, driver44drives translation element46along a translation axis48extending in lateral direction35to rotate transport track32about pivot42. In one example, driver44drives translation element46by a translation distance Xt to move registration end38of transport track32by a registration distance Xr in lateral direction35.

According to examples, translation axis48is disposed at a location other than at registration end38of the transport track32, such that translation axis48and registration end38are at different distances in transport direction33from pivot42. In one example, as illustrated, translation axis48is at a first distance, y1, in transport direction33from pivot42, and registration end38is at a second distance, y2, in transport direction33from pivot42. With translation element46and registration end38at different distances in transport direction33from pivot42, due to angular movement of transport track32when rotated about pivot42, movement of translation element46by a translation distance, Xt, along translation axis48results in movement of registration end38by a registration distance Xr that is different from translation distance, Xt. In one example, translation distance, Xt, is proportional to registration distance, Xr, but is not a one-to-one relationship.

If not accounted for, the proportional relationship between Xt and Xr may result in misalignment between edges of sheets of media34in lateral direction35at registration end38of transport track32, with the mismatch being greater the larger the difference between distances y1and y2and the greater the translation distance Xt. In one example, to compensate for such mismatch, in order to move registration end38of transport track32by a selected registration distance, Xr, driver44drives translation element46along translation axis48by a translation distance, Xt, equal to the selected registration distance, Xr, multiplied by an adjustment factor, Af (i.e., Xt=Af·Xr). In one example, adjustment factor, Af, is equal to a ratio of the first distance, y1, to the second distance, y2(i.e., Af=y1/y2), such that Xt=(y1/y2)·Xr.

By driving translation element46along translation axis48by a translation distance, Xt, that is equal to product of the selected registration distance, Xr, and the adjustment factor, Af, translator40accounts for the mismatch in travel distances between Xt and Xr resulting from the angular motion of transport track32about pivot42so that media registration system30is able to accurately align edges of sheets of print media34in lateral direction35.

FIG. 2is a block and schematic diagram illustrating a top view of media registration system30, according to one example, where transport track32includes a pair of parallel puller tracks50aand50b, where each puller track is rotatable around a corresponding pivot, such as illustrated by pivots42aand42b. In one example, each puller track,50aand50b, includes a puller clamp, such as puller clamps52aand52b, which are driven along puller tracks50aand50b, such as by a continuous belt, for example (not illustrated). In one example, each puller track may include more than one puller clamp. In examples, as described in greater detail below, puller clamps52aand52bopen and close as they travel along puller tracks50aand50b, with puller clamps52aand52bopening to receive a sheet of imaging media34at input end36of transport track32and then closing to capture and transport a received sheet of imaging media34along puller tracks50aand50bto registration end38. Upon reaching registration end38, puller clamps52aand52bopen to release the sheet of imaging media34(to a support surface, such as an output tray, for instance) and return to intake end36.

In one example, media registration system30includes a y-registration element, such as y-registration elements54aand54b, at registration end38. As described in greater detail below, y-registration elements54aand54bprovide surfaces which contact a leading edges of sheets of imaging media so as to provide registration (i.e., alignment) in transport direction33of edges of sheets of imaging media34, such as leading edges of the sheets of media34, as they are transported along puller tracks50aand50b.

In one example, puller clamps52aand52beach include a nip to secure sheet of imaging media34thereto. In one example, each nip is formed by a pair of biased rollers (not illustrated). According to such example, as puller clamps52aand52bpull sheet34along tracks50aand50b, a leading edge of sheet34contacts and is registered in transport direction33by y-registration elements54aand54b. As the leading edge of sheet34contacts and is registered by y-registration elements54aand54b, sheet34in prevented from movement in transport direction33. As puller clamps52aand52bcontinue to move along tracks50aand50bin transport direction33, sheet34is “pushed” from the nips of puller clamps52aand52bby y-registration elements54aand54b. Upon release from puller clamps52aand52b, sheet34is maintained on a support surface below puller tracks50aand50b, such as an output tray (not illustrated), for example. In this regard, it is noted that, in one example, when transporting a sheet of imaging media34, puller clamps52aand52bmove in transport direction33along a lower portion of puller tracks50aand50b, and after releasing sheet34return to intake end36along an upper portion of puller tracks50aand50bin a direction opposite to transport direction33.

In one example, translation element46is operatively coupled to puller tracks50aand50band is driven along translation axis48to respectively rotate puller tracks50aand50babout corresponding pivots42aand42bso as to provide alignment of sheets of imaging media34in lateral direction35at registration end38. In one example, driver44may be a motor45(e.g., a DC brushed motor) and translation element46may implemented as a rack and pinion system, having a rack47operatively coupled to puller tracks50aand50b, and a pinion49driven by motor45to drive the rack47back and forth along translation axis48to respectively rotate puller tracks50aand50babout pivots42aand42b. It is noted that in other examples, translator40may be implemented using other types of actuating systems, including linear actuators, for example.

In one example, translator40(which may also sometimes be referred to as an x-registration system) further includes a controller56and a sensor58. As described in greater detail below, according to examples, as puller clamps52aand52bpull sheets of imaging media34along puller tracks50aand50b, sensor58measures a position of sheets of imaging media34in lateral direction35. Based on the measured lateral position and employing the adjustment factor, Af, described above, for each sheet of imaging media34, controller56, via motor45(e.g., a DC brushed motor) and translation element46(e.g., rack and pinion gears47/49), rotates puller tracks50aand50babout pivots42aand42bto register edges of sheets of imaging media34in lateral direction35.

FIGS. 3A-3Cgenerally illustrate media registration system30and a method of aligning a series of sheets of imaging media34, such as received from an image forming apparatus (not illustrated), according to one example of the present disclosure. A series of such sheets of imaging media34may be referred to as a “job”, such as a “print job” in the case of a series of sheets of print media34being received from a printer, for instance.

In one example, as illustrated, translator40moves puller tracks50aand50bat registration end38over a range of registration distances Xr in the positive x-direction, where such range extends from a home position, where Xr is zero (such as along the y-axis, for example), to a maximum registration distance Xr in the positive x-direction (which is determined by a maximum translation distance, Xt, of translation element46). It is noted that puller tracks50aand50bare illustrated as being at the home position inFIG. 3A.

FIG. 3Aillustrates puller clamps52aand52bsecured to a leading edge60of a first sheet of imaging media34-1of an imaging job, such as a print job, at intake end36of media registration system30. In one example, prior to receiving a sheet of imaging media34, including first sheet of imaging media34-1, translator40moves translation element46to a home position so as to position puller tracks50aand50bat the home position (e.g., along the y-axis).

With reference toFIG. 3B, as puller clamps52aand52btransport first sheet34-1in transport direction33toward registration end38, with puller tracks50aand50bat the home position (solid lines), sensor58measures a position of a rear edge62of sheet34-1in lateral direction35relative to a reference, such as the y-axis, for example, where rear edge62is parallel to transport direction33. The measured position of rear edge62of the first sheet of imaging media34-1is indicated as X1inFIG. 3B.

In one example, as illustrated, after measuring the lateral position of rear edge62of sheet34-1, translator40rotates puller tracks50aand50babout corresponding pivot points42aand42bby moving translation element46by a translation distance Xt1(as illustrated by the dashed lines) so that the rear edge62is shifted in the positive x-direction by a selected offset distance, Xoff, when the first sheet of imaging media34-1reaches y-registration elements54aand54bat registration end38and is released from puller clamps52aand52b. According to one example, in view of the above, the translation distance of translation element46for the first sheet of the print job, Xt1, is equal to a product of the adjustment factor, Af, and the selected offset distance, Xoff (i.e., Xt1=Af·Xoff). In one example, pivot points42aand42bare positioned on a same axis lateral to transport direction33, such as along the x-axis as illustrated byFIG. 3A.

With reference toFIG. 3B, upon reaching registration end38, rear edge62is at a lateral distance from the y-axis (reference) which is equal to the sum of the initial position, X1, and the selected offset distance, Xoff. In one example, since translator40shifts puller tracks50aand50bin one direction from the home position (in this case, in the positive x-direction from the y-axis), the offset distance, Xoff, is selected such that the sum of X1(initial position) and Xoff (selected offset distance) is greater than an expected lateral position (position in the x-direction) of the rear edge of all remaining sheets of media of the print job. Since, according to such example translator40shifts puller tracks50aand50bin a positive x-direction, if a subsequent sheet34-nof the print job is at a distance greater than the sum of X1and Xoff, media registration system30will be unable to align the lateral edges of such sheet with initial sheet34-1.

With reference toFIG. 3C, for each subsequent sheet of imaging media of the print job, illustrated as sheet34-n, translator40returns puller tracks50aand50bto the home position (solid lines). After puller clamps52aand52breceive and transport each subsequent sheet34-nin transport direction33, sensor58measures the x-direction position of the rear edge62relative to the y-axis (i.e., the reference), as illustrated indicated at Xn. Translator40subsequently moves translation element46by a translation distance Xtn, such that the rear edge62of each subsequent sheet of imaging media34-naligns with the shifted position of the rear edge62of the first sheet of imaging media34-1(seeFIG. 3B), where Xtn is equal to the product of the adjustment factor Af and the sum of the offset distance, Xoff, and a difference between the measured position, X1, of the first sheet34-1and the measured position, Xn, of the subsequent sheet34-n(i.e., Xtn=Af·(Xoff+(X1−Xn)).

In this fashion, the lateral edges of all sheets of imaging media34of the print job are aligned (registered) at a distance of X1+Xoff from the y-axis (reference position). Additionally, the leading edges60of all sheets34of the print job are aligned in the y-direction by y-alignment features54aand54b. With all sheets of the print job aligned in both the x- and y-directions, additional operations can be performed, such as stapling, for example.

FIG. 4is a flow diagram generally illustrating a method100of registering imaging media sheets using a media registration system including a transport track that rotates about a pivot point, such as media registration system30ofFIG. 3Ahaving a transport track32comprising puller tracks50aand50bhaving corresponding pivots42aand42b. At102, such as illustrated byFIG. 3B, method includes transporting a series of imaging media sheets in a transport direction along the transport track to a registration end.

At104, with reference toFIG. 3B, for a first sheet of the series of imaging media sheets, such as first sheet34-1, the method includes driving a translation element operatively coupled to the transport track, such as translation element46coupled to puller tracks50aand50b, by a translation distance (Xt) along a translation axis48extending in a lateral direction35orthogonal to the transport direction33to rotate the transport track about the pivot and move the registration end from a home position by a selected offset distance (Xoff) in the lateral direction, the translation axis at a first distance (y1) and the registration end at a second distance (y2) in the transport direction from the pivot, the translation distance equal to a product of the selected offset distance and ratio of the first distance to the second distance.

In one example, at106, method100further includes measuring a position of a rear edge of the first sheet in the lateral direction from a reference with the transport track at the home position prior to driving the translation element along the translation axis, such as measuring a rear edge62of sheet34-1, as illustrated by the distance X1inFIG. 3B.

At108, for each subsequent sheet of the series, method100includes measuring a position of a rear edge of the subsequent sheet from the reference, such as measuring the distance Xn to the rear edge62of sheet34-n, as illustrated byFIG. 3C.

At110, for each subsequent sheet, method100includes driving the translation element46operatively coupled to the transport track by a translation distance, Xt, along the translation axis48to rotate the transport track about the pivot and move the registration end in the lateral direction from the home position, the translation distance equal to a product of the ratio of the first distance to the second distance and a sum of the offset distance and a difference between the measured positions of the first sheet and the subsequent sheet in the lateral direction, i.e., Xt=(y1/y2)·(Xoff+(X1−Xn), so as to align the rear edges of all sheets of the series of imaging media sheets align in the lateral direction at the registration end, such as illustrated byFIG. 3C.