Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-07-25
2003-01-14
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S065000
Reexamination Certificate
active
06505903
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for discharging liquid, a method to discharge desired liquid by generating bubbles by applying thermal energy to liquid, liquid discharge head and liquid discharge device, and in particular relates to a method for discharging liquid using a movable member that is displaced by generation of bubbles.
In addition, the present invention is applicable to an apparatus such as a printer to execute recording on a recording medium to be recorded, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, lumber, ceramics, a photocopier, a facsimile having transmission system, and a word processor having a printer part and the like and moreover to an industrial recording apparatus mixed in a complex fashion with various processing devices.
Incidentally, the term “recording” in the present invention means not only to form images having intelligence such as letters and drawings etc. to a recording medium to be recorded but also means to form images not having intelligence such as patterns etc.
2. Related Background Art
Liquid jet recording method, or so-called bubble jet recording method, that gives energy such as heat to ink (liquid) to cause liquid to undergo status change accompanying precipitous volume change (generation of bubbles) and discharges liquid from a discharge port with application force based on this status change, causes the liquid to attach onto a recording medium to be recorded, and proceeds with image forming, is conventionally known. For a recording apparatus using this bubble jet recording method, as disclosed in the U.S. Pat. No. 4,723,129 publication etc., a discharge port to discharge liquid, a liquid flow path to communicate with this discharge port, and an electro-heat converter as energy generating means for discharging liquid disposed inside the liquid flow path are generally provided.
Such a recording method enables recording of high density images at a high speed and with low noise, and can dispose the discharge port to discharge liquid at a high density in the head to execute this recording method, and therefore has a lot of excellent advantages so as to easily obtain recorded images and moreover color images as well with high resolution with a small apparatus. Therefore, this bubble jet recording method has recently been utilized for a lot of office apparatus such as a printer, a photocopier and a facsimile etc. and moreover has become utilized even for systems for industrial use such as a textile printing apparatus etc.
A schematic section view around an electro-heat converter of liquid discharge head of a prior art example to execute recording by such a recording method is shown in FIG.
10
. In the example shown in the above-described drawing, the electro-heat converter is constructed of a resistant layer
100
and electrodes
101
a
and
101
b
laminated thereon and formed as a pair having a gap. That is, the heat generating part
105
to generate heat by applying voltages is formed between the electrode
101
a
and the electrode
101
b,
and this part will become a bubble generation region where bubbles are formed by film boiling. In addition, above the resistant layer
100
and the electrodes
101
a
and
101
b,
two protection layers
102
and
103
protecting these are formed.
The discharge port to discharge liquid by generating a bubble
104
with heat generation at the heat-generating body
105
is disposed at a position facing the heat-generating body
105
such as the discharge port S (so-called side shooter type) or is disposed at the side direction such as the discharge port E (so-called edge shooter type). In any case, in the liquid discharge head with such construction, the bubble
104
grows comparatively large toward the liquid chamber side X with comparatively small flow path resistant, and therefore the bubble disappearance position
106
is likely to come to the center area of the heat-generating body
105
or a little bit biased to the direction of the liquid chamber side.
Thus, in the liquid discharge head as shown in
FIG. 10
, accompanied by growth of the bubble
104
, the liquid is largely pushed back to the direction of the chamber side X. Accordingly, a meniscus, that is formed in the discharge port side, being the surface between the liquid and the outside atmosphere, retreats comparatively fast accompanied by bubble disappearance after liquid discharge, and vibrates comparatively long. In addition, in the bubble disappearance steps, a flow of liquid toward the heat-generating body
105
from the liquid chamber side and a flow of liquid toward the heat-generating body
105
from the discharge port reach approximately the same level, and thus the timing when refilling of liquid to the discharge port side substantially commences comes after the flow of liquid from the discharge port side approximately stops and proceeds comparatively late, and therefore it takes a comparatively long time until the meniscus comes back to the normal position to be stabilized. Thus, in the case where liquid is discharged in a consecutive fashion, it is necessary to take a time interval comparatively long for discharge and there is a limit for a drive frequency that can enable liquid to be discharged properly.
In addition, as a liquid discharge head, one is known that has a construction that includes a movable member provided in the bubble generating region to undergo displacement and accompanied by growth of bubbles and a controller to control the displacement of the movable member within a desired range. The controller faces the bubble generating region of the liquid flow path so that substantial contact between the movable member having undergone displacement and the controller constitutes a substantially closed space except the discharge port. In this liquid discharge head, at the time of growth of bubbles, displacement of the movable member takes place to substantially close the upper stream side flow path of the bubble generation region. The liquid to be pushed back to the upstream side at the time of growth of bubbles is comparatively small. In addition, at the time of bubble disappearance, the movable member undergoes displacement so as to make the flow resistance at the upstream side small, and bubble disappearance at the upstream side of the bubble generation region is promoted to occur ahead than at the downstream side. Therefore, the retreat quantity of the meniscus is small and refill of liquid is executed efficiently.
In addition, in the liquid discharge head, the gas having melted into the liquid is released at the time when bubbles are formed, giving rise to a case where microbubbles are formed and remain behind. Under this circumstance, so that a quantity of these microbubbles does not remain to cause trouble, the liquid in the vicinity of the discharge port is sucked out and a recovery operation such as removal of microbubbles is executed on a regular basis. On the other hand, in the liquid discharge head comprising the movable member, the liquid is never pushed back to the upstream side, and therefore the microbubbles are released from the discharge port before increasing in number enough to cause trouble in the discharge operation, and hardly remain behind. Therefore, over a comparatively long period, consecutive recording can be executed and, at maximum, it is possible to execute recording of 100 sheets or more in a consecutive manner.
As described above, the liquid discharge head including a movable member has an advantage that it can execute refilling of liquid swiftly without giving rise to considerable retreat of the meniscus, and therefore uses a comparatively short time interval. Discharge of liquid can be executed, and driving with a comparatively high frequency is possible.
In addition, conventionally, in order to arrange for driving at a higher frequency, it is considered to be practically effective to cause the bubbles formed due to the aforesaid discharge to undergo bubble disappearance fast to arrange to execute
Ishinaga Hiroyuki
Misumi Yoshinori
Sugama Sadayuki
Sugiyama Hiroyuki
Taneya Yoichi
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Stephens Juanita
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