U.S. patent number 3,805,273 [Application Number 05/317,076] was granted by the patent office on 1974-04-16 for yoke mounted jet drop recording head.
This patent grant is currently assigned to The Mead Corporation. Invention is credited to Cyrus T. Brady, Peter L. Duffield, Philip H. Houser.
United States Patent |
3,805,273 |
Brady , et al. |
April 16, 1974 |
YOKE MOUNTED JET DROP RECORDING HEAD
Abstract
There is disclosed a recording head for a jet array recorder
wherein the electrical components thereof are attached to a
supporting yoke and the fluidic components thereof are suspended
within the yoke. The primary fluidic components are separately
assembled as a manifold subassembly and suspended inside a wobble
plate. The wobble plate in turn is inserted inside an inner yoke,
and rides within an "O" ring which provides freedom of movement for
vertical adjustment and tilting. Thus the manifold subassembly,
which includes an orifice plate provided with one or more rows of
jet orifices, may be accurately positioned with respect to the
inner yoke. In final assembly the inner yoke is mounted inside the
main supporting yoke to which the electrical components have been
attached and aligned. A set of dowel pins is provided to insure
alignment between the inner yoke and the outer yoke. There is also
disclosed means for supplying a flow of purging air through the
recording head and a magnetic catcher mounting arrangement. The
purging air is supplied to an air tube fitting which attaches to
the manifold subassembly. In the completed assembly the air flows
around the outside of the orifice plate and then exits the
recording head by flowing outwardly through apertures in a charge
ring plate which is fastened to the lower surface of the main yoke.
The catchers are mounted below the charge ring plate by attraction
to a set of permanent magnets which are set into the lower surface
of the main yoke.
Inventors: |
Brady; Cyrus T. (Dayton,
OH), Duffield; Peter L. (Kettering, OH), Houser; Philip
H. (Chillicothe, OH) |
Assignee: |
The Mead Corporation (Dayton,
OH)
|
Family
ID: |
23232004 |
Appl.
No.: |
05/317,076 |
Filed: |
December 20, 1972 |
Current U.S.
Class: |
347/74; 347/25;
347/34; 347/20; 347/21 |
Current CPC
Class: |
G01D
15/18 (20130101); C09D 11/02 (20130101); B41J
2/025 (20130101); B41J 2/105 (20130101) |
Current International
Class: |
B41J
2/105 (20060101); B41J 2/015 (20060101); B41J
2/07 (20060101); B41J 2/025 (20060101); G01D
15/16 (20060101); G01D 15/18 (20060101); C09D
11/02 (20060101); G01d 015/18 () |
Field of
Search: |
;346/75,140 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hartary; Joseph W.
Attorney, Agent or Firm: Biebel, French & Bugg
Claims
1. A recording head for a jet drop recording apparatus
comprising:
a yoke,
a manifold subassembly comprising a manifold bar and an orifice
plate communicating therewith,
means for removably mounting said subassembly within said yoke,
and
a charge ring plate provided with a series of charge rings, said
charge ring plate being mounted to an outer surface of said yoke
with said charge
2. Apparatus according to claim 1 said yoke extending around and
completely
3. Apparatus according to claim 1 said recording head further
comprising an elongated catcher magnetically held in place against
said outer surface of
4. Apparatus according to claim 3 further comprising a second
elongated catcher magnetically held in place against said outer
surface, and a
5. Apparatus according to claim 4 further comprising permanent
magnets mounted at each end of said yoke for grasping said
catchers.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is related to application Ser. No. 317,075 and
application Ser. No. 317,073 which were filed on even date herewith
and assigned to the assignee hereof.
BACKGROUND OF THE INVENTION
This invention relates to a recording head for jet drop recording
apparatus, and more particularly to a recording head which
generates one or more rows of jet drop streams. Typical prior art
recording heads are disclosed, for example, in Beam et al U.S. Pat.
No. 3,586,907 and Mathis U.S. Pat. No. 3,701,998. In such prior art
arrangements the jet streams are created by forcing a printing
fluid under pressure through one or more rows of orifices in an
orifice plate and stimulating the plate to cause break up of the
streams into uniformly sized drops. Further in these prior art
recording heads the orifice plate is bonded to a manifold into
which the recording fluid is introduced, and other necessary
recording head elements are attached to the manifold directly below
the orifice plate. Thus the recording head comprises an ink
manifold, an orifice plate, a charge ring plate, one or more
deflection strips, and one or more catchers, all assembled in a
stacked arrangement.
It has been found that such prior art arrangements are inconvenient
for assembly and cleaning, and that in normal operation there is a
tendency for dust and dirt to enter the assembly from the
outside.
SUMMARY OF THE INVENTION
This invention provides improved means for assembling and handling
a recording head for jet array recorder. In particular there is
provided a yoke into which the fluid holding manifold is suspended.
The orifice plate is attached to the manifold as in the prior art,
but other elements of the recording head are attached to the yoke.
Thus there is a physical segregation between the electrical and the
fluidic elements of the head. Consequently each of these groups of
elements may be assembled and checked out independently and brought
together in final assembly. This means that if an operating
difficulty is experienced because of orifice clogging or the like,
the manifold subassembly, which includes the orifice plate, may be
removed from the yoke without disturbing the charge plate,
deflection ribbon(s), or catcher(s). The yoke may have alignment
means thereon so that in the case of the above example, a
replacement manifold subassembly may be suspended in the yoke with
the original electrical elements still in place.
In a preferred embodiment of the invention there may be employed an
inner yoke as well as a main yoke and a wobble plate which fits
within the inner yoke. The manifold subassembly is fastened to the
wobble plate which is configured for adjusting movement within the
inner yoke. There is thus provided considerable freedom of movement
for aligning the orifice plate and directing the jets along correct
trajectories relative to the charge ring plate. Further, there may
be provided an air passage immediately above the charge ring plate
and around the manifold subassembly. A connection may be made to
this space from the outside for setting up a continuous flow of
purging air, and thereby preventing ingestion of any dirt or dust
into the printer head.
Accordingly it is an object of this invention to provide improved
means for assembling a recording head for a jet array recorder.
Other objects and advantages of the invention will be apparent from
the following description, the accompanying drawings and the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded pictorial view of a jet array printer head
employing the invention in a preferred embodiment;
FIG. 2 is an upwardly looking view of a fully assembled printer
head;
FIG. 3 is a view taken along lines 3--3 of FIG. 2;
FIG. 4 is a view taken along lines 4--4 of FIG. 2; and
FIG. 5 is a view taken along lines 5--5 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the invention is illustrated in exploded
form in FIG. 1 as including a manifold subassembly 10 which fits
into a wobble plate 15. Wobble plate 15 fits into an inner yoke 16
which in turn fits within a main yoke 17. There are also provided a
charge ring plate 32, a deflection ribbon 33, and a pair of
catchers 18, all of which are fastened to the lower surface of main
yoke 17 as hereinafter described.
Manifold subassembly 10 comprises a manifold bar 11, a cover plate
29, an orifice plate holder 12, and an orifice plate 13 which fit
together as illustrated in FIGS. 1 and 4. Thus orifice plate holder
12 fits upwardly into a cavity in the lower surface of manifold bar
11. Orifice plate holder 12 may be secured in place by screws (not
shown) and a fluid tight seal is provided between orifice plate
holder 12 and manifold bar 11 by an O-ring 14. Orifice plate 13 is
preferably soldered in place against the lower surface of orifice
plate holder 12. Manifold subassembly 10 is thus an integral unit
which may be assembled and flushed clean prior to any association
with any of the electrical components of the recording head.
As further illustrated in FIG. 1, manifold bar 11 and cover plate
29 are provided with internal passages into which may be inserted
an ink supply tube 20, an ink return tube 21, a stimulator 23, and
an air tube fitting 24. Stimulator 23 has a probe which reaches
downwardly for contact with orifice plate 13. Orifice plate 13 is
excited to propagate a series of traveling bending waves as
described in detail in Lyon et al., Ser. No. 189,297, and
stimulator 23 is rotatably adjustable as described in Houser, U.S.
Pat. No. 3,701,476. Air tube fitting 24 is used for applying a flow
of purging air to the recording head. A flow of air supplied by a
fan or other means (not shown) flows downwardly through air tube
fitting 24 and thence into an air cavity 25 in manifold bar 11. The
purging air then follows a path as generally illustrated in FIG. 4
to exit the recording head through charge ring apertures 26 in
charge ring plate 32. This keeps foreign matter out of the charge
ring apertures and also provides a stabilizing effect for the
liquid jets. The jet stabilizing effect, which forms no part of
this invention, is described in Sweet, U.S. Pat. No. 3,596,275.
Once assembled, manifold subassembly 10 is fitted downwardly into
wobble plate 15 and fastened thereto as by screws (not shown).
Wobble plate 15, with manifold subassembly 10 attached thereto, is
fitted downwardly into inner yoke 16 with an O-ring 27
therebetween. It will be appreciated that wobble plate 15 may be
adjusted upwardly or downwardly or tilted within inner yoke 16 for
adjustment of jet filament lengths to meet requirements as
discussed in Ser. No. 189,297. For this purpose there are provided
three lifting screws 65 and three hold down screws 66.
Independently of the assembly of manifold subassembly 10, the
electrical elements of the recording head may be assembled as a
unit by fastening to main yoke 17 as illustrated also in FIG. 1.
Charge ring plate 32 is attached directly to the main yoke 17, as
are also catchers 18. Charge ring plate 32 is fastened in place by
a series of screws, and catchers 18 are secured by means of four
cylindrical magnets 34 which are bonded into recesses in the lower
surface of main yoke 17. Magnets 34 are common insulated ceramic
magnets which are commercially available from many sources.
Preferably magnets 34 are made of barium-ferrite ceramic embedded
in insulating plastic and are provided with lead-out pole pieces.
Catchers 18 are preferably fabricated from a magnetic stainless
steel material so that they are firmly grasped by magnets 34.
Lateral adjustment of catchers 18 is provided as best illustrated
in FIG. 5 by set screws 35 and adjusting nuts 36. Each adjusting
nut 36 is provided with a small downwardly projecting pin 37 which
reaches into a mating slot in the upper surface of the associated
catcher 18. Set screws 35 reach through openings in yoke 17 for
threaded engagement with nuts 36. Thus catchers 18 may be adjusted
inwardly or outwardly to provide any desired spacing between the
catcher faces and the surfaces of deflection ribbon 33. Catchers 18
are elongated devices as described in detail in copending patent
application, Docket 5725. Each catcher is equipped with two vacuum
tubes 41 and one vacuum tube 59.
Deflection ribbon 33 is stretched between a pair of tension blocks
38 which in turn are fastened to main yoke 17 as by screws 39.
Tension blocks 38 are provided with set screws 40 so that the
tension blocks may be adjusted back and forth in the longitudinal
direction (see FIG. 2). Set screws 40 are initially adjusted to
enable easy insertion of deflection ribbon 33 between tension
blocks 38. Thereafter deflection ribbon 33 is drawn to a taut
condition.
In operation there are created two rows of drop streams which are
selectively charged and caught all as described in detail in
Mathis, U.S. Pat. No. 3,701,998. For this purpose charging signals
representative of graphic information are applied to terminals 42
of charge ring plate 32. These charging signals cause selective
charging of drops 44 (see FIG. 4) which are directed toward a
recording medium 43. A static electrical field for the deflection
of the charged drops is set up between the deflection ribbon 33 and
each of catchers 18. Appropriate deflection fields are set up by
attaching deflection ribbon 33 and catchers 18 to sources of
different electrical potential. Preferably catchers 18 are
grounded, and deflection ribbon 33 is connected to a source of high
negative potential. Accordingly the data system (not shown) applies
a positive electrical pulse to one of terminals 42 for each drop or
drop packet which is to be caught. These drops, which are
negatively charged in response to such pulses, are deflected to
impact against the face of one of catchers 18 for ingestion
therein. Those drops which are not charged strike recording medium
43 to produce a graphic impression.
It will be appreciated that the alignment tolerances between
orifice plate 13 and charge ring plate 32 are quite critical.
Accordingly the mounting apertures in charge ring plate 32 and
cover plate 29 are oversize to permit minor alignment correcting
adjustments. In the usual assembly process manifold subassembly 10
is mounted within wobble plate 15, and thereafter the combined
assembly is mounted within inner yoke 16. At this point wobble
plate 15 may be adjusted and cover plate 29 may be shifted for
precise positioning of orifices 28 relative to inner yoke 16. Then
charge ring plate 32 may be mounted on main yoke 17 with charge
rings 26 accurately positioned after which inner yoke 16 is fitted
into main yoke 17. A pair of precisely positioned dowel pins 45
insure accurate alignment of yoke 16 with yoke 17 and hence
accurate positioning of orifices 28 relative to charge rings 26.
Alternatively the head may be assembled as above described, but
with orifices 28 being directly aligned relative to charge rings 26
as a post assembly procedure. This latter adjustment procedure may
be carried out on a trial run basis with a suitable liquid actually
filling the recording fluid manifold and forming into jet drop
streams. In any event, once the required alignment has been
achieved, inner yoke 16 may be removed from main yoke 17 as desired
for cleaning or flushing of the fluid components. Then so long as
the adjusting screws have not been touched, the head may be
reassembled without further aligning adjustment. Thus there is
achieved a practical segregation between the fluidic and the
electrical components of the recording head.
While the form of apparatus herein described constitutes a
preferred embodiment of the invention, it is to be understood that
the invention is not limited to this precise form of apparatus, and
that changes may be made therein without departing from the scope
of the invention.
* * * * *