Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2003-01-29
2004-11-16
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S009000, C347S011000, C347S014000
Reexamination Certificate
active
06817704
ABSTRACT:
This application claims priority to Japanese Patent Application Number JP2002-239797 filed Aug. 20, 2002, Japanese Patent Application Number JP2002-320862 filed Nov. 5, 2002, and Japanese Patent Application Number JP2002-334220 filed Nov. 18, 2002, all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technology in which, in a liquid ejecting device having a head including at least one liquid ejecting portion and in a liquid ejecting method using a head including at least one liquid ejecting portion, a current-mirror circuit is used to deflect liquid ejected from each liquid ejecting portion, and to a technology for simplifying (downsizing) entire circuit structure.
2. Description of the Related Art
Inkjet printers have been conventionally known as a type of liquid ejecting device having heads which each include 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 a head structure using the thermal method, ink in an ink cell is heated by a heating element (heating resistor) disposed in the ink cell to produce bubbles in the ink on the heating element, and the energy of the generation 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 head in the width direction of printing paper. In the line method, many heads are arranged in the width direction of printing paper to form a line head for the width of the printing paper.
FIG. 21
is a plan view showing a line head
10
of the related art. Although
FIG. 21
shows four heads
1
(N−1, N, N+1, and N+2), a larger number of heads
11
are actually arranged in parallel.
In each head
1
, a plurality of (normally, approximately hundred units of) ink cells, heating elements, and nozzles
1
a
as described above are arranged in parallel. The line head
10
is formed by arranging the heads
1
in a predetermined direction (the width direction of printing paper).
Two adjacent heads
1
in the predetermined direction are disposed on one side and the other side across an ink-flow pass
2
extending in the predetermined direction, and the head
1
on the one side and the head
1
on the other side are alternately disposed so that both opposes each other, that is, nozzles
1
a
can oppose each other. Between the adjacent heads
1
, the pitch of the nozzles
1
a
is consecutively maintained, as shown in the detail of portion A in
FIG. 21
(see Japanese Unexamined Patent Application Publication No. 2002-36522).
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 a head chip including the ink cells and the heating elements, the problem is positional shifting of the nozzle sheet. 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 positional shifting occurs between the central axis of the ink cells and the heating elements and the central axis of the nozzle
1
a
, the ink cannot be ejected perpendicularly to the ejection surface. In addition, positional shifting can be caused by a difference in coefficient of thermal expansion between the nozzle sheet, and the ink cells and the heating elements.
When such a difference in angel of ejection of ink occurs, it appears as a shift in pitch of delivered ink in the case of the serial method. In the case of the line method, the difference appears as a positional shift between two heads
1
, in addition to the shift in pitch of delivered ink.
FIGS. 22A and 22B
are a sectional view and plan view showing printing by the line head
10
shown in FIG.
21
. In
FIGS. 22A and 22B
, 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 (FIG.
22
B).
In the section view in
FIG. 19A
, among the line head
10
, three heads
1
, that is, the N-th head
1
, the (N+1)-th head
1
, and the (N+2)-th head
1
are shown.
As shown in the section view in
FIG. 22A
, in the N-th head
1
, ink is slantingly ejected in the left direction as is indicated by the left arrow. In the (N+1)-th head
1
, ink is slantingly ejected in the right direction as is indicated by the central arrow. In the (N+2)-th head
1
, ink is perpendicularly ejected without a shift in angle of ejection as is indicated by the right arrow.
Accordingly, in the N-th head
1
, the ink is delivered, being off to the left from a reference position, and in the (N+1)-th head
1
, the ink is delivered, being off to the right from the reference position. Thus, between both, the ink in the N-th head
1
and the ink in the (N+1)-th head
1
are delivered to opposite directions. As a result, a region in which no ink is delivered is formed between the N-th head
1
and the (N+1)-th head
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 head
1
and the (N+1) head
1
, thus causing a problem of deterioration in printing quality.
Similarly to the above case, in the (N+1)-th head
1
, the ink is delivered, being off to the right from the reference position. Thus, the (N+1)-th head
1
and the (N+2)-th head
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.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a liquid ejecting device having a head including a liquid ejecting portion or liquid ejecting portions arranged in parallel and a liquid ejecting method using a head including a liquid ejecting portion or liquid ejecting portions arranged in parallel, wherein the direction of liquid ejected from each liquid ejecting portion is controlled.
The present invention provides a circuit form that is particularly suitable for the case of incorporating means of deflecting ejected liquid with a head in technology in Japanese Patent Application Nos. 2002-112947 and 2002-161928 which have already been filed by the Assignee of the present Application. Also, in the present invention, by simplifying (downsizing) the entire circuit, the means can be used even for a head having a resolution of 600 dpi or higher.
According to a first aspect of the present invention, a liquid ejecting device having a head including a liquid ejecting portion or a plurality of liquid ejecting portions arranged in parallel in a predetermined direction is provided. The liquid ejecting portion or each of the liquid ejecting portions includes a liquid cell for co
Eguchi Takeo
Ikemoto Yuichiro
Takenaka Kazuyasu
Ushinohama Iwao
Depke Robert J.
Do An H.
Holland & Knight LLP
Meier Stephen D.
Sony Corporation
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