Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-08-30
2002-09-03
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06443552
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a carriage moving apparatus for transmitting a driving force to a carriage by a toothed timing belt to thereby reciprocally move the carriage, and a recording apparatus and a reading apparatus using the same, respectively.
2. Related Background Art
In a so-called serial recording apparatus wherein a recording head is carried on a carriage and recording is effected on a recording medium while the carriage is moved, an image is formed on the recording medium while the conveyance of the recording medium and the recording effected with the movement of the carriage are alternately repeated.
The carriage which is main scanning means of the serial type is usually driven by a belt from a drive source such as a motor through pulleys. This belt is usually mounted by two pulleys, and in order to prevent the slack thereof, tension is applied thereto by the pulley on one side.
In order to effect main scanning of higher accuracy, it is generally practiced to prevent bad recording such as slip by the use of a so-called toothed timing belt and toothed timing pulleys which are a belt and pulleys provided with uneven shapes.
There have heretofore been various methods of coupling the timing belt and carriage in such a recording apparatus, and in any of these coupling methods, the belt and carriage are coupled together so that no backlash may be present in that portion of the carriage which is coupled to the belt.
FIG. 8
of the accompanying drawings schematically shows the construction of the belt-coupled portion of a recording apparatus according to the prior art. The belt-coupled portion
101
having a concavity is formed integrally on a carriage
100
, as shown, and the concavity has an expause somewhat wider than the thickness of a timing belt
103
. One of convex portions defining the concavity is formed with unevenness so as to mesh with the teeth of the timing belt
103
, and the timing belt
103
is inserted into the concavity and cylindrical pins
104
are forced thereinto, whereby the timing belt
103
is fixed to the carriage
100
.
A method of coupling the concavity of the belt-coupled portion
101
and the timing belt
103
together is such that the timing belt
103
made of an elastic material such as rubber is urged by the fixing pins
104
, whereby the carriage
100
and the timing belt
103
are coupled together so that there may be no backlash.
However, such a method of coupling the timing belt
103
and the carriage
100
together in the recording apparatus according to the prior art suffers from the following problems.
In the driving system by the timing belt
103
, the timing belt
103
is vibrated by the vibration of a carriage motor which is the drive source of the carriage
100
or the timing belt
103
is vibrated by vibration caused when the toothed timing pulleys and the timing belt
103
mesh with each other. This vibration is sometimes transmitted to a recording head carried on the carriage
100
because the carriage
100
is firmly fixed. This causes bad recording and causes the production of noise such as the resonation of parts incorporated in the carriage
100
.
Particularly when a stepping motor is used as the carriage driving motor, the vibration during driving tends to occur.
So, Japanese Patent Application Laid-Open No. 6-47978 proposes a construction as shown in
FIG. 9
of the accompanying drawings. That is, a carriage
100
is provided with a coupling hole portion
100
a
which is formed so as to permit a belt-coupled portion
101
to be loosely fitted therein. Also, unevenness is formed on the belt-coupled portion
101
so as to mesh with the unevenness of a timing belt
103
, and a gap for inserting the timing belt
103
thereinto is provided in the belt-coupled portion
101
with the same width as that of the timing belt
103
. The timing belt
103
is inserted into this gap, whereafter the belt-coupled portion
101
coupled to the timing belt
103
is further inserted into the coupling hole portion
100
a
of the carriage
100
.
The belt-coupled portion
101
is all or partly formed by a molded article or a member having elasticity. By the belt-coupled portion
101
being thus formed by an elastic member, it is made difficult for the vibration of a carriage driving motor transmitted by the timing belt
103
to be transmitted to the carriage, whereby good image formation is realized.
Also, the belt-coupled portion
101
is loosely fitted in the coupling hole portion
100
a
provided in the carriage, and this portion also serves to absorb the transmitted vibration.
However, when adopting the construction as described In Japanese Patent Application Laid-Open No. 6-47978, the following problems have been found in obtaining Images of higher dignity,y That is, the belt-coupled portion
101
is loosely fitted to the carriage
100
and therefore, when the carriage
100
is stopped, the backlash of the fitting may affect the stopped position of the carriage. Particularly in this construction, there is a distance between the timing belt engaging portion of the belt-coupled portion and the fitted portion of the belt-coupled portion to the carriage and therefore, an angular moment is applied to the belt-coupled portion
101
and the backlash is increased, and this tends to increase the influence upon the stopped position of the carriage.
If the stopped position of the carriage becomes unstable by such backlash and the choice of the carriage driving construction is mistaken, for example, in an ink jet recording apparatus, the carriage cannot be stopped at a predetermined location due to the presence of the aforementioned backlash when the carriage is to be stopped at the predetermined location in order to bring a cap for protecting the nozzle of a recording head into close contact with the periphery of the nozzle, and leak occurs between the cap and the nozzle and the nozzle dries, and this leads to the possibility that the ink jet recording head becomes incapable of discharging ink.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a carriage moving apparatus which can prevent vibration transmitted from a vibration source such as a motor by a timing belt from transmitting to a carriage, and enhance the stoppage accuracy of the carriage and avoid any inconvenience by the instability of the stopped position of the carriage, and a recording apparatus and a reading apparatus using the same.
It is another object of the present invention to provide a carriage moving apparatus which can reliably effect engagement between a timing belt and a carriage, and a recording apparatus and a reading apparatus using the same.
It is still another object of the present invention to provide a carriage moving apparatus for transmitting a driving force to a carriage by a toothed timing belt to thereby reciprocally move the carriage, which is designed such that belt projected portions provided on the timing belt and having their central axes passing through substantially the widthwise center of the timing belt, and protruding to the opposite sides with the timing belt interposed therebetween are engaged with a carriage engaging portion formed on the carriage.
REFERENCES:
patent: 4084681 (1978-04-01), Heinzl et al.
patent: 4723129 (1988-02-01), Endo et al.
patent: 4740796 (1988-04-01), Endo et al.
patent: 5200767 (1993-04-01), Tsukada et al.
patent: 5465107 (1995-11-01), Mayo et al.
patent: 5801728 (1998-09-01), Yanagi et al.
patent: 6-47978 (1994-02-01), None
Hasegawa Koh
Inoue Hiroyuki
Iwasaki Takeshi
Kawasaki Noriko
Kida Akira
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Vo Anh T. N.
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