Interposer device and striker strip assembly therefor

An interposer device for an impact band line printer comprises a spring steel interposer plate member with plural chevron flexure elements etched therein so that the apexes thereof are arranged in a row across the plate. A polymer striker strip has a series of cutouts configured in a herringbone pattern and forms a longitudinal spine section with support ribs connecting the spine section to the margins of the strip. Two sided pressure adhesive tapes attached along the margins of the strip are bonded to the surface of the interposer plate with the spine section aligned with but unattached with the apexes of the chevron elements. A laminated interposer strip assembly comprises a polymer striker strip layer with adhesive attachment layers on one side along the margins and a backing layer removably attached to the other side of the striker strip layer.

FIELD OF THE INVENTION 
This invention relates to printing and more particularly to an interposer 
device and striker strip assembly usable therewith for condensed printing 
in an on-the-fly high speed impact line printer. 
RELATED APPLICATION 
Application of E. F. Helinski, entitled "Printer Apparatus For Printing At 
Different Print Densities", Ser. No. 07/915,445, filed concurrently 
herewith. 
BACKGROUND OF THE INVENTION 
In the related application, an interposer device is disclosed comprising an 
interposer plate slotted to form flexure elements and a striker strip 
interposed between the flexure elements and the print hammers to protect 
the flexure elements against wear due to fretting corrosion. In one 
embodiment of the interposer device disclosed, the flexure elements are 
chevron flexure elements disposed symmetrically across the plate. The 
apexes of the chevron elements are uniformly spaced and arranged in a row 
substantially co-extensive with a row of print hammers, the row of apexes 
defining a strike zone when aligned with the print hammers. The striker 
strip is preferably a thin compliant polymer layer material interposed 
between the print hammers and the row of apexes and preferably is attached 
to the side of the interposer plate facing the print hammers with the 
strip being aligned with but not attached to the apexes of the chevron 
elements. 
Because of its necessarily compliant nature, the striker strip after a 
period of use develops a certain amount of slack and the edges of the 
strip tend to curl and form a rollover which can adversely affect the 
transfer of energy from the print hammers to the flexure elements. 
SUMMARY OF THE INVENTION 
The subject invention overcomes these problems by providing an interposer 
device comprising an interposer plate member slotted to form a plurality 
of flexure elements disposed symmetrically across the plate which are 
deflectable from the plane of the plate and a striker strip constructed 
and attached to the plate in manner which prevents the strip from folding 
over during use. The flexure elements are preferably chevron flexure 
elements with the apexes thereof arranged in a row across the plate. The 
invention further provides a striker strip assembly which is easy to 
handle and can be easily attached to the surface of the interposer plate 
member in proper alignment with the apexes of the chevron apexes. In 
accordance with this invention, the striker strip is a thin polymer-like 
strip made with a series of cutouts which form a longitudinal spine 
section connected by support ribs to the margins of the strip on either 
side of the spine section. The cutouts preferably are arranged in a 
herringbone pattern and the support ribs are slanted at the same angle and 
in the same direction as the flexible arms of the chevron flexure elements 
of the interposer plate. The striker strip is attached to the interposer 
plate by attachment means, preferably adhesive tapes bonded to the margins 
of the striker strip, with the spine section in overlaying but unattached 
alignment with the row of apexes of the chevron flexure elements. Such a 
structure provides a striker strip which is highly compliant, with less 
slack producing stress and eliminates the problem of rollover. In a second 
embodiment, the series of cutouts is formed with first and second 
herringbone patterns to form a longitudinal spine section with two sets of 
flexible slanted ribs, the sets of ribs being slanted in opposite 
directions. This arrangement solves the problem of excess stress of the 
spine section which can be caused by multiple strikes of hammers at 
different points along the spine section. 
The striker strip assembly according to the invention is a laminated strip 
assembly comprising a thin polymer-like striker strip member layer with 
cutouts forming a longitudinal spine section with ribs connecting the 
spine section to margins of the strip member, mounting tape layers 
adhesively attached to the margins on one side of the striker strip layer 
and a removable backing layer on the other side of the striker member acts 
as a stiffener for the striker strip assembly and protection for the 
striker strip member until the interposer device itself is to be installed 
into the printer apparatus. The backing layer may be an opaque material 
and in which case it is made with cutouts in a herringbone pattern aligned 
with the cutouts of the striker strip layer so that the positioning of the 
spine section can be visually observed during attachment of the assembly 
to the interposer plate. The spine and rib construction enables the 
striker member to be compliant with minimum extraction of impact energy 
from the print hammers and eliminates foldovers of the strip member. The 
striker strip assembly is easy to handle and apply to the interposer plate 
in proper alignment. 
The foregoing and other features and advantages of the invention will be 
readily apparent from the following more particular description of 
preferred embodiments of the invention as illustrated in the accompanying 
drawings.

DETAILED DESCRIPTION OF THE INVENTION 
As shown in the FIG. 1, an interposer device 10 in accordance with the 
invention comprises interposer plate 11 and a portion of a striker strip 
12 assembly attached to one side of interposer plate 11. As seen more 
clearly in FIG. 2, interposer plate 11 has a plurality of chevron flexure 
elements 13 disposed symmetrically across plate 11. Flexure elements 13 
comprise apex sections 14 supported by acutely slanted arms 15 and 16 
connected to the plate 11. Apex sections 14 are aligned in a longitudinal 
row across plate 11 and constitutes the strike zone for print hammers (not 
shown) of an impact line printer apparatus. Plate 11 preferably is made of 
metal such as spring or stainless steel and has a thickness in the range 
of 0.006 to 0.010 inches. Flexure elements 13 are preferably formed by 
etching slots into plate 11. In this manner, the flexure elements 13 can 
be made dimensionally very precise and the slots can be kept very small to 
avoid gaps in printing of characters as discussed in greater detail in the 
aforementioned related application. Mounting apertures 17 in plate 11 are 
provided for installing interposer device 10 into an impact band line 
printer apparatus (not shown). 
As seen more clearly in FIGS. 3 and 4, striker strip assembly 12 is a 
laminated assembly comprising a striker strip layer 18, attachment layers 
19 and 20 along the margins on one side of layer 18 and a backing layer 21 
on the other side of strip layer 18. Striker strip layer 18 is made with a 
series of cutouts 18a in a herringbone pattern to form a longitudinal 
spine section 18b and support ribs 18c which connect spine section 18b to 
margins 18d and 18e of strip layer 18. Preferably striker strip layer 18 
is a transparent polymer material marketed under the tradename 
FAIRPRENE1/2 and has a thickness in the range of 0.002 to 0.004 inches. 
With such material and structure spine section 18b is compliant along 
three axes as indicated by direction arrows A-C. Arrow A indicates the 
axis of primary motion imparted to the spine section 18b by print hammers. 
Arrow B indicates a second axis of compliance also essential to achieve 
the primary motion without stretching spine section 18b. Arrow C indicates 
a third axis of compliance required to prevent stretching of the strip 
member and energy loss. The compliance along the three axes provides 
minimal restriction of movement of the spine 18b. Such compliance is 
possible due to the flexibility provided by the support ribs 18c. 
Attachment layers 19 and 20 are two sided pressure sensitive adhesive 
tapes, one side of the tapes being attached by pressure bonding to the 
margins 18d and 18e of striker strip 18. Protective layers 22 cover the 
other side of attachment layers 19 and 20 and are removable for attachment 
of the striker strip layer 18 to the surface of interposer plate 11 with 
the spine section 18b in overlaying alignment with the row of apex 
sections 14 of the chevron flexure elements 13. 
Backing layer 21, which can be substantially thicker than the strip layer 
18 if desired, provides rigidity and protection to the thin strip layer 18 
during handling and bonding to the surface of interposer plate 11. Backing 
layer 21 is attached to layer 18 by a low strength adhesive which allows 
layer 21 to be peeled off after strip 18 is bonded to plate 11. A suitable 
material for backing layer 21 is 3M Brand #9415 Backer Paper or a vinyl 
film. Such a material may be opaque in which case, backing layer 21 would 
have cutouts 21a coincident with the cutouts in strip layer 18 so that the 
alignment of the spine section 18b with the apexes 14 can be readily 
observed. 
In the embodiment of FIG. 5, striker strip layer 18 has cutouts 18f and 18g 
configured in accordance with two herringbone patterns arranged end to end 
and each covering one half of the length of spine section 18b. In this 
configuration, spine section 18b is connected to margins 18d and 18e by 
two sets of support ribs 18h and 18i each set slanted in opposite 
directions. This arrangement provides freedom of motion in two directions 
along the axis of spine section 18b as indicated by direction arrows D and 
E. This arrangement relieves tension stress in spine section 18b when 
impacts occur substantially simultaneously at multiple locations along the 
length of the spine section. 
While the invention has been particularly shown and described with 
reference to preferred embodiments thereof, it will be understood by those 
skilled in the art that various changes in form and details may be made 
therein without departing from the spirit and scope of the invention.