Bi-axial staggered printing array

Details Bi-axial staggered printing array Bi-axial staggered printing array

1999-08-11

2002-02-12

Nguyen, Thinh (Department: 2861)

Incremental printing of symbolic information

Ink jet

Ejector mechanism

C347S020000

Reexamination Certificate

active

06345879

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to industrial printers and specifically to printing heads and printing arrays.
BACKGROUND OF THE INVENTION
Industrial ink jet printer heads are generally constructed in either a vector or a matrix configuration. As is described in their respective names, vector printer heads include an array of ink jet nozzles arranged in a row or vector configuration, while matrix printers include a bi-dimensional array of ink jet nozzles arranged in a matrix.
One of the factors influencing the choice of printer head configurations is the desired line quality, which is defined by the number of printed dots per inch (dpi). The typical industrial standard for line quality is 600 dpi; however, this factor may increase or decrease depending on the printer capability and consumer requirements.
An additional factor influencing printer head configuration is physical mechanical restraints. The ink jet chamber is relatively large, much larger than the ink dot that it produces, and the industry engages in a perpetual search for improved ways to squeeze more ink jet nozzles into a smaller and smaller area by reducing the chamber size. U.S. Pat. No. 5,777,637 describes one such nozzle arrangement.
Reference is now made to
FIGS. 1 and 2
, which illustrate prior art vector printing heads and methods.
FIGS. 1A and 1B
are schematic diagrams of an ink jet nozzle configuration of a page wide printing head
10
and a sheet of paper
12
, and a sample of printing produced with head
10
, respectively. For purposes of clarity, the latitudinal axis of paper
12
has been marked Y and the longitudinal axis has been marked X.
Head
10
comprises a row of nozzles
14
positioned along the Y-axis, which operate and eject ink in a manner known in the art for ink jet printing nozzles. For purposes of clarity,
FIG. 1A
illustrates a limited number of nozzles
14
; however, the quantity of nozzles
14
and the distance between them may vary from printer to printer depending on the desired dpi and the width of the paper
12
.
As illustrated in
FIG. 1A
, head
10
is laterally positioned above paper
12
, and remains static while paper
12
moves in a longitudinal direction, marked by arrow
13
, underneath the head.
FIG. 1B
is an illustration of a printing sample produced by head
10
. A vertical line
16
is comprised of a continuity of ink dots
17
, as is known in the art and the thickness and quality of line
16
is determined by the printed dot size, dot ejection frequency and paper advance speed. A width W is the distance between line
16
and a line
18
and is determined by the distance between nozzles
14
.
Illustrated in
FIGS. 2A and 2B
is an additional example of a vector-printing head
20
. Similar elements from
FIGS. 1A and 1B
are identified by similar numbers and letters.
Similar to head
10
, head
20
is positioned over paper
12
, and comprises a row of nozzles
14
. In contrast to head
10
, which comprised a page wide row of nozzles
14
on the Y-axis, head
20
comprises a row of nozzles
14
positioned on the X-axis.
Head
20
is laterally positioned along the X-axis of paper
12
and, in a process well known in the art, transverses the Y-axis of paper
12
from side M to side N, thus printing on the section of paper
12
which falls underneath the head's path. Paper
12
then increments the printed portion of the paper forward in the direction marked by arrow
13
, and head
20
transverses paper
12
again, returning from side N to side M. The process of head transversal and paper incrementation is repeated until printing is completed for paper
12
. The path of print coverage on the page is marked by dotted line
15
.
FIG. 2B
is an illustration of the printing produced by head
20
and shows a horizontal line
16
comprised of a continuity of dots
17
, a horizontal line
18
also comprising dots
17
, and a width W between two lines
16
and
18
. Similar to head
10
, lines
16
and
18
, are determined by the printed dot quality and dpi produced by head
20
, and distance W is determined by the distance between nozzles
14
.
To overcome the physical limitations of inter-nozzle row width W, prior-art printing heads use the staggered nozzle construction as shown in FIG.
3
.
Head
30
comprises a plurality of nozzles
14
arranged in a staggered array having parallel angled rows, referenced
38
and
40
, and parallel columns, referenced A, B and C. Head
30
is not restricted to any specific array pattern and may comprise one, two or more angled rows of nozzles
14
, depending on the application
For purposes of clarity, the uppermost nozzle
14
in angled row
38
is labeled
38
a,
the second uppermost nozzle
14
in column
38
is labeled
38
b,
and so on. The numbering for row
40
is similar to that of column
38
; the uppermost nozzle in column
40
is labeled
40
a,
the second uppermost nozzle
14
is labeled
40
b,
and so on. Similar labeling is applicable for all columns and rows in head
30
.
The rows of nozzles in head
30
are not aligned directly parallel on the Y-axis. Each of the rows
38
and
40
are offset at an angle from the Y-axis. The angle &thgr; is flexible and is determined by the desired print quality, as will be explained hereafter.
Thus, in the example shown, nozzle
38
b
is offset a distance W with respect to nozzle
38
a
, in the X direction and similarly nozzle
38
c
is offset a distance W with respect to nozzle
38
b
The angling of the rows produces an array of nozzles
14
, which are offset or angled or staggered with respect to the Y-axis. While the shortest physical distance between adjacent nozzles
14
, measured on the Y-axes, is D, the distance between adjacent nozzles measured on the X-axes is W. The staggering of nozzles results in W<<D, depending on the choice of angle &thgr;.
If more than one angled row
38
is used, the spacing B in the X direction, between the rows
38
and
40
will be such that the last nozzle
38
j
in row
38
will be spaced from the first nozzle
40
a
at a distance W measured on the X-axis.
The printing produced by head
30
, moving in the Y direction, as shown by arrow
32
, is illustrated by horizontal parallel lines
52
a,
52
b,
52
c
to
52
j,
part of nozzle row
38
, and lines
54
a,
54
b,
54
j
part of nozzle row
40
. Lines
52
,
54
are formed by a continuity of ink dots
17
.
The structure of staggered nozzle array can achieve for example a printing line resolution of 200 dpi in the X direction by defining W=1/200″.
It should be noted that by a proper choice of angle &thgr;, the physical distance between adjacent nozzles D is about 1.5 to 2.0 mm.
The head
30
is useful for printing at 200 dpi only if the head (or sheet of paper) moves in the direction
32
, moving the same head
30
in the Y-direction will result in a much inferior dpi number.
This limitation is problematic, where the flexibility of moving the printing head at high dpi resolution in both X, Y directions is preferred.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to provide a printing head that prints to a high resolution on both the latitudinal and longitudinal axes.
It is an additional object of the present invention to provide a printing head that is interchangeable between printers.
The present invention is a bi-axial staggered matrix-printing head.
There is thus provided in accordance with a preferred embodiment of the present invention, a printing head having a bi-axial nozzle array. The bi-axial nozzle array includes a plurality of nozzles arranged in a two-dimensional staggered array configuration, whereby the printing head is capable of printing along first and second axes, the first axis being perpendicular to the second axis.
Furthermore, in accordance with a preferred embodiment of the present invention the staggered array configuration includes a plurality of rows and plurality of columns, the plurality of columns being offset at an angle &agr; from the first axis and the plurality of rows being offset at an a

Affiliated with

Also associated with

Rating

Bi-axial staggered printing array does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Bi-axial staggered printing array, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bi-axial staggered printing array will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2951818