Ink-jet recording head

Details Ink-jet recording head Ink-jet recording head

1999-10-19

2001-03-27

Le, N. (Department: 2861)

Incremental printing of symbolic information

Ink jet

Ejector mechanism

C347S020000, C347S068000

Reexamination Certificate

active

06206499

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an ink-jet recording head for ejecting ink droplets through nozzle orifices to record images or characters on a recording sheet, and in particular to the structure of a head cover for protecting a recording head.
As is shown in
FIG. 14
, an ink-jet recording apparatus
1
is so designed that a carriage
3
is movably attached to a guide member
2
and is connected to a timing belt
6
that is wrapped around a drive pulley
4
and a follow-up pulley
5
and that a pulse motor
7
reciprocally moves the carriage
3
in the direction of the width of a recording sheet
8
(main scanning).
A recording head
9
is located on the face of the carriage
3
opposite the recording sheet
8
, or on the bottom face in this example. During the main scanning, ink supplied from an ink cartridge
10
is ejected as ink droplets to the recording sheet
8
to record characters and images thereon.
As is shown in
FIG. 15
, for the recording head
9
, a channel unit
16
is constituted by laminating a nozzle plate, in which a plurality of arrays of a plurality of nozzle orifices
11
are formed, a channel forming substrate
14
, in which a plurality of pressure generating chambers corresponding to the nozzle orifices
11
and an ink supply chamber are formed, and an elastic sheet
15
, which transmits the vibration of piezoelectric vibrators
12
to change the volume of the pressure generating chambers. The channel unit
16
is bonded on the surface of a casing
17
with an adhesive, and the distal ends of the piezoelectric vibrators
12
are brought into contact with the elastic sheet
15
and are securely retained in the casing
17
.
The channel unit
16
is fixed to the casing
17
by a conductive head cover
19
in which a window is formed to expose the nozzle orifices
11
, so that the nozzle plate
13
can be prevented from being damaged due to paper stacking, and electric charge can be prevented.
When one part of ink in ink droplets ejected from the nozzle orifices
11
remains on the surface of the nozzle plate
13
, this ink may be mixed with ink for the other nozzle arrays, or may change the direction in which ink droplets are dispersed and may deteriorate the printing quality.
In order to wipe ink that remains on the nozzle plate
13
, as is shown in
FIG. 14
, a wiper plate
20
that can ascend and descend on the nozzle face is provided at the location outside the recording available range. When the wiper blade
20
is elevated as needed and is brought in contact with the nozzle plate
13
and when the carriage
3
is reciprocally moved in this condition, the ink remaining on the nozzle plate
13
is wiped away by the wiper blade
20
, and the printing quality is recovered.
However, since the external circumference of the recording head
9
is covered with the head cover
19
, a wiper blade
20
that is longer than the width of the recording head
9
is elastically deformed by application of a specific force and contacts the nozzle plate
13
. If a specific force is not applied, the wiper blade floats in contact with the head cover
19
on the nozzle plate, and does not contact the face of the nozzle plate. Thus, the ink remaining in an area close to the head cover
19
can not be completely wiped.
SUMMARY OF THE INVENTION
To resolve this problem, it is one objective of the present invention provide an ink-jet recording head that can completely remove ink remaining in an area where nozzle orifices are formed.
To achieve the above objective, according to the present invention, there is provided an ink-jet recording head comprising:
a casing;
a nozzle plate provided on the casing and having a plurality of nozzle orifices formed therein;
a channel unit provided between the nozzle plate and casing for ejecting ink drops from the nozzle orifices by use of pressure generating means;
a head cover for covering side faces of the casing and edge portions of a top face of the nozzle plate and for defining a wiping space for which the surface of the nozzle plate is wiped by a wiper, the wiping space situated lower than the top face of the nozzle plate.
At least in the nozzle forming area, the wiper blade is uniformly brought in contact with the nozzle plate without being disturbed by the head cover, and the wiper blade scrapes residual ink under uniform pressure.


REFERENCES:
patent: 5534898 (1996-07-01), Kashino et al.
patent: 5539435 (1996-07-01), Uchida et al.
patent: 5956058 (1999-09-01), Momose et al.
patent: 6027208 (2000-02-01), Amano
patent: 790129 (1997-08-01), None
patent: 861725 (1998-09-01), None
Patent Abstracts of Japan, vol. 1997, No. 9, Sep. 30, 1997 (JP 09-123463).

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