Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2003-01-30
2004-06-15
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06749286
ABSTRACT:
This application claims priority to Japanese Patent Application Number JP2002-112947 filed Apr. 16, 2002, and Japanese Patent Application Number JP2002-320861 filed Nov. 5, 2002, both of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technology for controlling flying characteristics of liquid or a position to which liquid is delivered and to liquid ejecting device and method in which liquid in liquid cell is ejected from a nozzle. The present invention specifically relates to, in liquid ejecting device including heads each having a plurality of liquid ejecting portions arranged in parallel and liquid ejecting method using the heads each having the ejecting portions arranged in parallel, a technology for controlling a direction (a direction in which liquid is delivered,) in which liquid is ejected from each liquid ejecting portion.
2. Description of the Related Art
Inkjet printers have been conventionally known as a type of liquid ejecting device including heads which each have a plurality of liquid ejecting portions arranged in parallel. A thermal method that uses thermal energy to eject ink is known as one of ink ejecting methods for inkjet printers.
In an example of printer-head chip structure using the thermal method, ink in an ink cell is heated by a heating element disposed in the ink cell to produce bubbles in the ink on the heating element, and the energy of the production of the bubbles ejects the ink. A nozzle is formed in the upper side of the ink cell. When the bubbles are produced in the ink in the ink cell, the ink is ejected from the ejecting outlet of the nozzle.
From the viewpoint of head structure, there are two methods, a serial method and a line method. In the serial method, an image is printed by moving a printer-head chip in the width direction of printing paper. In the line method, many printer-chip heads are arranged in the width direction of printing paper to form a line head for the width of the printing paper.
FIG. 18
is a plan view showing a line head
10
of the related art. Although four printer-head chips
1
(N−1, N, N+1, and N+2) are shown in
FIG. 18
, actually, more printer-head chips are arranged.
In each printer-head chip
1
, a plurality of nozzles
1
a
having ejecting outlets for ejecting ink are formed. The nozzles
1
a
are arranged in parallel in a given direction, and the given direction is identical to the width direction of the printing paper. Also, the printer-head chips
1
are arranged in the given direction. Adjacent printer-head chips
1
are arranged so that their nozzles
1
a
oppose each other, and in a portion in which two printer-head chips
1
are adjacent to each other, the pitch of the nozzles
1
a
is consecutively maintained (see the detail of portion A in FIG.
18
).
The related art shown in
FIG. 18
has the following problems.
When ink is ejected from the printer-head chips
1
, it is ideal that the ink is ejected perpendicularly to the ejection surface of the printer-head chips
1
. However, various factors may cause a case in which an angle at which the ink is ejected is not perpendicular.
For example, when a nozzle sheet having the nozzles
1
a
formed thereon is bonded to the upper side of ink cells having heating elements, the problem is that positional shifting occurs between pairs of the ink cells and the heating elements, and the nozzles
1
a
. When the nozzle sheet is bonded so that the center of the nozzles
1
a
is positioned in the center of the ink cells and the heating elements, the ink is ejected perpendicularly to the ink ejection surface (the nozzle sheet surface). However, if a shift occurs between the ink cells and the heating elements, and the nozzles
1
a
, the ink cannot be ejected perpendicularly to the ejection surface.
Also, a positional shift can occur due to a difference in thermal expansion factor between the pairs of the ink cells and the heating elements, and the nozzle sheet.
It is assumed that, when the ink is ejected perpendicularly to the ejection surface, an ink droplet is delivered to an ideally exact position. When the angle of ejection of the ink is shifted from perpendicularity by &thgr;, positional shift &Dgr;L in delivery of ink droplet is
&Dgr;
L=H
×tan &thgr;
with the distance (normally 1 to 2 millimeters in the case of the inkjet method) between the ejection surface and the surface (a surface on which the ink droplet is delivered) of printing paper set to H (H is constant).
When such a shift in angle of ejection of the ink occurs, in the serial method, the shift in angle appears as a shift in delivery of ink between two nozzles
1
a
. In the line method, in addition to the shift in delivery of ink, the shift in angle appears as a positional shift in delivery between two printer-head chips
1
.
FIGS. 19A and 19B
are respectively a section view and plan view showing the state of printing performed by the line head
10
(in which the printer-head chips
1
are arranged in parallel in a direction in which the nozzles
1
a
are arranged) shown in FIG.
18
. In
FIGS. 19A and 19B
, assuming that printing paper P is fixed, the line head
10
does not move in the width direction of the printing paper P, and performs printing while moving from top to bottom of the plan view in FIG.
19
B.
In the section view in
FIG. 19A
, among the line head
10
, three printer-head chips
1
, that is, the N-th printer-head chip
1
, the (N+1)-th printer-head chip
1
, and the (N+2)-th printer-head chip
1
are shown.
As shown in the section view in
FIG. 19A
, in the N-th printer-head chip
1
, ink is slantingly ejected in the left direction as is indicated by the left arrow. In the (N+1)-th printer-head chip
1
, ink is slantingly ejected in the right direction as is indicated by the central arrow. In the (N+2)-th printer-head chip
1
, ink is perpendicularly ejected without a shift in angle of ejection as is indicated by the right arrow.
Accordingly, in the N-th printer-head chip
1
, the ink is delivered, being off to the left from a reference position, and in the (N+1)-th printer-head chip
1
, the ink is delivered, being off to the right from the reference position. Thus, between both, the ink in the N-th printer-head chip
1
and the ink in the (N+1)-th printer-head chip
1
are delivered to opposite directions. As a result, a region in which no ink is delivered is formed between the N-th printer-head chip
1
and the (N+1)-th printer-head chip
1
. In addition, the line head
10
is only moved in the direction of the arrow in the plan view in
FIG. 19B
without being moved in the width direction of the printing paper P. This forms a white stripe B between the N-th printer-head chip
1
and the (N+1) printer-head chip
1
, thus causing a problem of deterioration in printing quality.
Similarly to the above case, in the (N+1)-th printer-head chip
1
, the ink is delivered, being off to the right from the reference position. Thus, the (N+1)-th printer-head chip
1
and the (N+2)-th printer-head chip
1
have a common region in which the ink is delivered. This causes a discontinuous image and a stripe C which has a color thicker than the original color, thus causing a problem of deterioration in printing quality.
When such a shift in a position to which ink is delivered occurs, the degree to which a stripe looks noticeable depends on an image to be printed. For example, since a document or the like has many blank portions, a stripe will not look noticeable if it is formed. Conversely, in the case of printing a photograph image in almost all the portions of printing paper, if a slight strip is formed, it will look noticeable.
For the purpose of preventing the formation of such a stripe, Japanese Patent Application No. 2001-44157 (hereinafter referred to as “Earlier Application 1”) has been filed by the Assignee of the present Patent Application. In the invention of Earlier Application
1
, a plurality of heating elements (he
Depke Robert J.
Gordon Raquel Yvette
Holland & Knight LLP
SOny Corporation
LandOfFree
Liquid ejecting device and liquid ejecting method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid ejecting device and liquid ejecting method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid ejecting device and liquid ejecting method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3310225