Adjustable compliance of separation strips in a media dam

Abstract

In a copier, printer, or similar device, paper is loaded in large quantities. To separate a top sheet of a stack of sheets from the next adjacent sheet, a dam is used, which is an element having an inclined surface in the path of the top sheet. This invention addresses devices with variably compliant separation strips, preferably a thermoplastic polyurethane elastomer such as Pellethane®, that are part of the dam, so that the leading edge of a media sheet will strike the inclined surface of the separation strip. By adjusting the compliance of the separation strip, different weights of media may be accommodated while minimizing the multi-feeds that may cause jamming of the device.

Claims

1. An apparatus for adjusting the compliance of separation strips in a dam of a printer media tray comprising: a printer; a media tray; a dam adjacent the front end of the media tray; at least one separation strip in the dam; a non-compliant wedge element that interferes with compression movement of a spring that would allow the separation strip to flex in response to the media load, wherein the wedge element is a blade.

2. The apparatus according to claim 1, wherein the blade is housed inside of the dam element without interfering with the separator strips.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The attached drawings illustrate preferred embodiments of the invention, in which:

(2) FIG. 1 is a side view of a printer;

(3) FIG. 2 is a side view of a printer tray having separation strips of the present invention with a stack of sheets of media therein and shown enlarged for clarity purposes;

(4) FIG. 3 is an inverted perspective view of the separator bracket assembly with a non-compliant blade element in a storage position;

(5) FIG. 4 is an inverted perspective view of the separator bracket assembly with a non-compliant blade element withdrawn from the storage position;

(6) FIG. 5 is an inverted perspective view of the separator bracket assembly with a non-compliant blade element in position for insertion;

(7) FIG. 6 is a view of the separator bracket assembly with a non-compliant blade element inserted;

(8) FIG. 7 is a top view of the assembly with the unimpeded spring element;

(9) FIG. 8 is a top view of the assembly with a bearing plate adjusted to impede the compression travel distance of the spring element; and

(10) FIG. 9 is detail view of the separator strip spring assembly.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(11) Referring to the drawings, and particularly to FIGS. 1 and 2 thereof, there is shown a tray 111 used in a printer 101. The tray 111 supports a plurality of sheets 201 of a media such as bond paper, for example, in a stack. The sheets may be other media such as labels, envelopes, or card stock, for example. To separate a top sheet of a stack of sheets 201 from the next adjacent sheet through using a dam 211, which is an element having an inclined surface in the path of the top sheet, as it is fed from the stack of sheets 201, so that its leading edge will strike the inclined surface of the dam. In FIG. 2, the separator bracket assembly 221 with an inclined surface is shown as the top section of the dam 211.

(12) In a first embodiment, a non-compliant blade 301, or other wedge element, is inserted, see FIGS. 5 and 6, to stop the compliance of the separator strips 311A, 311B in the assembly. The blade interferes with the compression movement of the spring 701A, 701B (shown in FIG. 7) that would allow the separator strips 311A, 311B to flex in response to the media load. When the separation strips are non-compliant, the pick performance of heavier media such as vinyl labels and card stock is improved when the pick-mechanism 231 roller grabs the paper to feed it into the printer such that fewer multi-feeds are observed. When feeding lighter media that is efficiently picked without multi-feeds, the wedge or blade element 301 can be housed inside of the dam element as shown in FIG. 3 without interfering with the separator strips. The blade element 301 is shown in the stored position in FIG. 3, withdrawn from the stored position in FIG. 4, positioned to insert in the non-compliance position in FIG. 5, and inserted in the non-compliance position in FIG. 6.

(13) In a second embodiment, the user may operate a wheel-type cam system, or other device, to move a wedge element into position to lessen or eliminate the compliance of the separator strip elements. Pre-set positions may be selected depending on the particular weight of the media in use.

(14) In the previous embodiments, the compliance of the separator strips is controlled by limiting the travel distance of an element of the separator strip, e.g., 311B, shown in FIG. 9 such as a protruding piston 901 positioned within the spring element 911, where the blade element 301 limits the travel distance of the piston. Other elements of the separator strip assembly such as the backing element 921 of the separator strip may contact a surface to prevent further travel.

(15) In a third embodiment shown in FIGS. 7 and 8, the compression travel distance of the spring 701A, 701B, and thus the force in the spring, is adjusted to control the compliance of the separator strips. A plate 711A, 711B, or other element, that serves as the back bearing surface of the spring element may be adjusted. In FIG. 7, the plate 711A, and 711B is shown in the extended position allowing a full range of compression of the spring 701A, 701B. In FIG. 8, the plate 811A, and 811B is shown in an adjusted second position that limits the range of compression of the spring 801A, 801B. The adjustment may be implemented manually by the user, or automatically by the system in response to the media characteristics, using either set points or continuously variable positions. The media characteristics may be input by the user, or measured by the system during operation.

(16) For purposes of exemplification, particular embodiments of the invention have been shown and described according to the best present understanding thereof. However, it will be apparent that various changes and modifications in the arrangement and construction of the parts thereof may be made without departing from the spirit and scope of the invention as defined in the appended claims.