Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-07-09
2003-10-21
Stephens, Juanita (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S058000
Reexamination Certificate
active
06634736
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to ink-jet recording heads and ink-jet recording apparatuses using the same. In particular, the present invention relates to an ink-jet recording head, a circuit board for an ink-jet recording head, an ink-jet recording head cartridge, and an ink-jet recording apparatus in which bubbles are produced in ink by using thermal energy generated by heat-generating resistors and the ink for recording is ejected by expansion and contraction of the bubbles and in which the resistance of wiring electrodes for supplying electric power to the heat-generating resistors is made uniform between each wiring electrode.
2. Description of the Related Art
Various ink-jet recording heads are known, in which ink droplets to be ejected are formed in different ways. Conventional recording apparatuses use these recording heads which perform recording in such a manner that the ejected ink droplets adhere to recording media such as sheets of paper. In particular, the ink-jet recording heads which use heat as an energy for producing the ink droplets to be ejected can be provided relatively easily with multiple ink ejection ports disposed in high density, whereby high speed, high resolution, and high quality recording is made possible.
A so-called side-shooter-type ink-jet recording head is known as a recording head which ejects ink by using thermal energy. In the side-shooter-type ink-jet recording head, ink droplets are upwardly ejected substantially in perpendicular to a plane along which heat-generating resistors for generating thermal energy are disposed. In the recording head of this type, the ink is generally supplied through an ink supply opening which is formed passing through a circuit board provided with the heat-generating resistors, the ink being supplied from the rear side of the circuit board.
FIGS. 22 and 23
show the known side-shooter-type inkjet recording head.
FIG. 22
is a perspective view of a part of the circuit board, which is exposed by cutting away a part of a member which defines ink ejection ports.
FIG. 23
mainly shows wiring electrodes in plan provided on the circuit board of the recording head.
In the side-shooter-type ink-jet recording head shown in
FIG. 22
, a plurality of electrothermal transducers (hereinafter referred to as heaters)
802
disposed on a circuit board
805
and in a staggered way at sides of an ink supply opening
803
which is formed passing through the circuit board
805
. The circuit board
805
is provided with a member formed thereon, which defines ink ejection ports
801
opposing the respective electrothermal transducers
802
and associating with ink flow paths
804
.
The circuit board
805
shown in
FIG. 23
is provided thereon with source-side common wiring electrodes
902
a
and
902
b
for selectively driving the plurality of heaters
802
to eject ink in accordance with recording data, heat-generating resistors forming the electrothermal transducers
802
and wiring electrodes for supplying electric power thereto, driving devices such as transistors (shown in black in the drawing and formed at a lower layer side), and ground-side common wiring electrodes
904
a
and
904
b.
These wiring electrodes and circuits are connected in series to each other. Each source-side or ground-side common wiring electrode
902
a
or
902
b
, or
904
a
or
904
b
can be electrically connected to the outside of the circuit board
805
through electrode pads
903
. Inter-layer insulative films, protective films, and the like are omitted from these drawings.
In the ink-jet recording head thus formed, ink is held so as to form a meniscus in the vicinity of each ink ejection port
801
. The ink is quickly boiled at heated surfaces by using thermal energy produced by the heaters
802
selectively driven in accordance with recording data, whereby the ink is ejected by pressure of bubbles generated when the ink is boiled.
Electric energy or power to be applied to a heater for ejecting ink is an important factor which affects the quality of ink ejection. That is, when the electric energy varies, the state of ink-bubble development varies, whereby there is a risk that the ink is not ejected as designed. For example, when the electric energy, that is, driving energy is not sufficiently applied, there is a risk that film boiling of the ink is unstably performed, whereby the speed, direction, and amount of ejection of the ink droplets may vary, thereby deteriorating the quality of recorded images and producing kinks, shabbiness, scratchiness, etc. When the driving energy is excessively applied, a mechanical stress is given to the electrothermal transducers and film boiling of the ink is unstably performed, whereby the quality of ejection of the ink droplets is deteriorated, as described above, and the recording head may be damaged in the worst case.
Therefore, energy having the same value is preferably inputted into each of the plurality of heaters and the amount of the energy to be inputted into each heater is preferably constant.
It is known that the amount of energy inputted to each heater varies when the number of heaters of a head driven at the same time varies. That is, the voltage-drop value varies according to the number of heaters driven at the same time which varies according to the recording data and the like, thereby changing the driving energy inputted to each heater.
A configuration as a countermeasure to this problem is devised in that, as shown in
FIG. 23
, wiring electrodes between the heaters
802
and the electrode pads
903
and between the driving devices and the electrode pads
903
are divided into a plurality of wiring electrodes, and a resistance value in each wiring electrode
902
a
,
902
b
,
904
a
, or
904
b
is substantially the same, for example, as disclosed in Japanese Patent Laid-Open No. 10-44416. With this arrangement, the difference in voltage drop at each common wiring electrode between a case in which all the heaters are driven and the case in which a single heater is driven can be reduced, whereby the same amount of driving energy can be applied to each heater.
In the above known configuration, the voltage drop produced when driving the heaters due to the common wiring electrodes is reduced. The resistance of wiring is reduced by increasing the width of each common wiring electrode
902
a
,
902
b
,
904
a
, or
904
b
, and the resistance of the wiring electrodes
902
a
,
902
b
,
904
a
, and
904
b
is made uniform by differing the widths of the common wiring electrodes
902
a
,
902
b
,
904
a
, and
904
b
from each other according to the lengths of the common wiring electrodes
902
a
,
902
b
,
904
a
, and
904
b
, respectively, as widths A and B shown in
FIG. 23
differ from each other.
Recently, ink-jet recording apparatuses generally use recording heads each provided with a plurality of heaters highly densely integrated with each other so as to obtain high-resolution and high-quality images at high speeds. On the other hand, the recording heads are required to be reduced in size. Therefore, it is very difficult to uniform resistance values of wiring electrodes from electrode pads to heaters only by controlling the width of each wiring electrode under the condition in which the size of the recording head cannot be increased.
Since the size of a circuit board is increased when intending to uniform the resistance of wiring electrodes only by controlling the width of each wiring electrode, manufacturing costs are increased because the number of substrates obtained from one silicon wafer is reduced, and the size of the recording head is increased due to the increased size of the substrate. When a plurality of heaters are driven according to divided time-sharing groups, variations in the amount of driving energy to be applied may be reduced by increasing the number of divisions in timesharing groups, thereby reducing the number of heaters which are simultaneously driven. However, the recording head is generally driven at a high frequency du
Komuro Hirokazu
Miyakoshi Toshimori
LandOfFree
Ink-jet recording head, circuit board for ink-jet recording... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink-jet recording head, circuit board for ink-jet recording..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink-jet recording head, circuit board for ink-jet recording... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3135750