Print liquid tank and printing apparatus having the same

Details Print liquid tank and printing apparatus having the same Print liquid tank and printing apparatus having the same

2001-04-17

2003-02-04

Gordon, Raquel Yvette (Department: 2853)

Incremental printing of symbolic information

Ink jet

Controller

C347S019000, C347S014000

Reexamination Certificate

active

06513891

ABSTRACT:

This application is based on Patent Application No. 2000-117064 filed Apr. 18, 2000 in Japan, the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a print liquid tank for supplying a print liquid to a print head that prints on a printing medium, and to a printing apparatus having the print liquid tank.
2. Description of the Related Art
A continuous type large industrial printing apparatus was once a mainstream ink jet printer. An ink jet printer as a printing apparatus using an on-demand type ink jet print head came into wide use. As for an ink storage system in the ink jet print head, when a faster printing speed of the ink jet print head began to increase the ink consumption in recent years, the merits of the ink storage bag that can provide a large capacity of ink storage relatively easily ,received attention. This is because, as there are growing demands for more varied kinds of prints, from conventional monochromatic prints to color prints of symbols and characters to high vivid prints such as photographic images, the number of inks used and the amount of each ink consumed have increased dramatically. For example, a conventional monochromatic print of A4 size uses 30-60 mg of ink per sheet at most whereas a full color image print requires about 500-2000 mg/sheet.
There are many proposals concerning the ink storage system using the bag in an ink storage system, and many proposals concerning system for detecting an amount of ink remaining in the ink storage bag are open to the public.
The system for measuring the amount of ink remaining in the ink storage bag has a mechanism that visually indicates the remaining amount of ink, as disclosed for example in Japanese Patent Application Laid-open Nos. 158977/1980 and 211482/1983.
While many technologies have been proposed publicly which concern the ink storage bag and system which measure the amount of ink remaining in the ink storage bag, but, they are mostly not put to practical use or, if adopted, only for a short period of time.
Among the reasons for this are a problem of a precision at which the remaining amount of ink is detected, a problem of increased steps in the assembly process, a problem that the remaining amount of ink can only be indicated but cannot be fed back to the printer body, and a problem of requiring a generous cost increase for implementing the feedback.
Examples of the conventional systems are detailed below. In Japanese Patent Application Laid-open Nos. 45638/1972 and 21443/1976, for example, the amount of remaining ink is detected based on a change in the amount of light passing through the ink. This method detects not the actual amount of the remaining ink but only the presence or absence of the ink. That is, it has a drawback of being unable to detect a change in the ink consumption and also a drawback of requiring a mechanism for generating light and a device for detecting the amount of light transmitted and converting the detected light output into a digital value or electric signal.
Proposed methods other than the one based on the change in the amount of light that has passed through the ink include one in which an ink level displacement resulting from the consumption of ink in the ink storage bag arranged inside a case is converted by a strain-resistance gauge into a change in electric resistance (Japanese Patent Application Laid-open No. 34966/1982); one which converts the ink level displacement into a change in electrostatic capacitance (Japanese Patent Application Laid-open No. 34990/1982); one having a mechanism that visually displays the ink level displacement as above(Japanese Patent Application Laid-open No. 158977/1980, 211482/1983); and one that converts the ink level displacement into a change in the amount of reflected light or magnetism (Japanese Patent Application Laid-open No. 194855/1984, 169679/1993).
In these non-contact detection systems (based on electrostatic capacitance for example), variations in the deformations of the individual ink storage bags that may degrade the detection precision must be considered. Particularly in the systems that detect changes in the electrostatic capacitance and magnetism, these changes are inversely with the square of the distance , which is disadvantageous to the detection of the remaining mount of ink. This is because an initial change is large and a change at the last stage extremely small, making it difficult to detect a final point in the amount of remaining ink (minimum amount of remaining ink), the most critical information.
In the case of a light reflection type ink consumption detection unit, as shown in Japanese Patent Application Laid-open No. 169679/1993 and in
FIGS. 14A and 14B
, an ink consumption detection unit
6
is rigidly held inside a case
2
so that it faces an ink storage bag
4
(hereinafter referred to also as an ink bag) accommodated in the case
2
.
The ink bag
4
is provided at one of its ends with a joint portion
8
which has a needle
10
communicating the interior of the ink bag
4
with the interior of the print head to supply the ink IN contained in the bag to the print head.
The ink consumption detection unit
6
comprises a light emitting element portion
6
A, which has a light emitting diode LED or infrared LED to emit a light beam toward the surface of the ink bag
4
made from an aluminum foil composite film, and a light receiving element portion
6
B that detects the light beam reflected from the surface of the ink bag
4
. A signal output from the light receiving element portion
6
B of the ink consumption detection unit
6
and representing an amount of reflected light corresponding to the reflectivity is an analog signal and thus requires an A/D converter to produce a signal that indicates the remaining amount of ink.
Although the ink consumption detection unit
6
is shown to be small relative to the ink bag
4
in
FIGS. 14A and 14B
, the size of the unit
6
is difficult to reduce. The ink consumption detection unit
6
measures e.g. about 30 mm high by 15 mm wide by 40 mm long. One of the reasons that the unit
6
has such a large size is that the ink bag
4
has a thickness or height of at least 5 mm in connection with a minimum required amount of stored ink (at least 20 ml or more) and that the unit
6
is required to have a sufficient depth of focus to cover the change in the bag height. Among other reasons result from design conditions that consider the formation of a light path between the light emitting element portion
6
A and the light receiving element portion
6
B, the mounting of these elements to the substrates and to the case
2
and the securing of wiring portions of the substrates. Further, the arrangement of the ink consumption detection unit
6
at the side of the ink bag
4
increases an idle space within the case
2
, deteriorating the accommodation efficiency of the case
2
.
When the ink bag
4
changes its state from
FIG. 14A
in which it is filled with a predetermined amount of ink IN to
FIG. 14B
in which the ink IN is consumed, the ink consumption detection unit
6
outputs a signal representing the amount of reflected light in response to a change in degree of light reflectance.
At the time, the ink bag
4
is formed of a reflective aluminum foil composite film and, because of the presence of the joint portion
8
, has a sufficient rigidity not to collapse completely when the ink IN is consumed. Hence, there are some variations in the thickness of the bag. In such cases, variations in the reflection direction of the light beam in the ink consumption detection unit
6
and variations in the amount of reflected light detected by the light receiving element portion
6
B may combine to make the precise detection impossible. To prevent this, a spring member that urges the ink bag
4
in the contract direction needs to be installed in the case
2
. If such a spring member is provided, the ink residual amount detection of this system cannot be realized with good reproducibility witho

Affiliated with

Also associated with

Rating

Print liquid tank and printing apparatus having the same does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Print liquid tank and printing apparatus having the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Print liquid tank and printing apparatus having the same will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3144128