Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-06-16
2002-07-23
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06422680
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an ink jet recording apparatus being placed on a reciprocatively movable carriage for jetting ink drops toward recording paper in response to print data, thereby printing on the recording paper and a cleaning control method in the recording apparatus and in particular to a cleaning control technique for eliminating an atmosphere valve communicating with a capping unit for sealing a recording head and simplifying an ink discharge sequence from the recording head executed by the capping unit. It also relates to a recording apparatus for solving a problem of contaminating recording paper, etc., by waste ink stored in the capping unit that can be produced by eliminating the atmosphere valve.
An ink jet recording apparatus produces relatively small noise at the printing time and moreover can form small dots at a high density and therefore recently has been used for various types of printing including color printing.
Such an ink jet recording apparatus comprises an ink jet recording head which receives supply of ink from an ink cartridge and is reciprocated in a main scanning direction and a paper feeder for carrying recording paper in a subscanning direction orthogonal to the recording head and jets ink drops from the recording head based on print data, thereby recording on the recording paper.
A recording head capable of jetting black, yellow, cyan, and magenta inks, for example, is placed on a carriage and the color ink jetting percentage can be changed for executing full color printing as well as text printing in black ink.
The described ink jet recording head involves a problem of clogging nozzle orifices and causing a print failure because of a rise in ink viscosity caused by evaporation of a solvent from the nozzle orifices, solidification of ink deposition of dust, mixing of air bubbles as ink pressurized in a pressure generating chamber is jetted to recording paper as ink drops from the nozzle orifices for printing. Thus, this kind of ink jet recording apparatus comprises a capping unit for sealing the nozzle formation face of the recording head at the non-printing time.
The capping unit functions as a lid for preventing ink in the nozzle orifices of the recording head from being dried. In addition, if the nozzle orifices are clogged, the capping unit also provides an ink jet capability recovery function of sealing the nozzle formation face by the capping unit and sucking and discharging ink from the nozzle orifice by a negative pressure from a suction pump for unclogging the nozzle orifices.
The forcible ink suction and discharge treatment executed for unclogging the recording head is called cleaning operation; to restart printing after a halt for a long time or when the user recognizes a print failure and, for example, operates a cleaning switch, the cleaning operation is executed. A negative pressure produced by the suction pump is added and ink is sucked from the recording head and discharged into the capping unit, then the nozzle formation face is wiped out by a wiping member formed of a rubber material, etc., for example.
The capping unit is placed, for example, at an end of the recording apparatus out of a print area (home position) and is mounted on an elevating mechanism that can be lifted up to the nozzle formation face side of the recording head by a driving force of the carriage accompanying a move of the carriage to the home position side.
A recovery function of applying a drive signal not related to printing to the recording head for idly jetting ink drops, called flushing operation, is also provided. It is executed every given period for recovering an irregular meniscus if the irregular meniscus occurs in the proximity of the nozzle orifice of the recording head and preventing clogging as viscosity of ink is increased in the nozzle orifice less jetting ink drops during printing.
FIG. 12
is a top view of the configuration of a capping unit
71
in related art used for the described cleaning operation. The capping unit
71
is placed at an end (home position) out of the placement position of a paper guide plate
72
forming a print area.
A recording head mounted on a carriage (not shown in FIG.
12
and described later) is guided by a guide rod so that it can move just above the paper guide plate
72
and the capping unit
71
.
The capping unit
71
comprises a cap member
73
formed of a flexible rubber material, etc., that can seal the nozzle formation face of the recording head positioned just above the capping unit
71
and has a function of sealing the nozzle formation face of the recording head at the non-printing time for preventing ink in the nozzle orifices firm being dried and a function of receiving a negative pressure from a suction pump (described later) and forcibly discharging ink from the recording head at the cleaning operation time.
Thus, a cap holder
74
on which the cap member
73
is mounted is placed on an elevating mechanism that can be lifted up to the nozzle formation face side of the recording head by a driving force of the carriage accompanying a move of the carriage to the home position side.
An ink absorbing sheet
75
is housed in the cap member
73
and the cap member
73
is formed at an inner bottom part with an ink suction port
76
. One end of a tube forming a part of a tube pump (not shown) is connected to the ink suction port
76
.
The cap member
73
is formed at an inner bottom part with an atmosphere port
77
. A tube
78
is connected at one end to the atmosphere port
77
and connected at an opposite end to a valve
79
. The valve
79
is opened and closed by a valve body
80
and the valve body
80
is placed in a state normally closing the valve
79
by a spring
81
. The valve body
80
is molded integrally with a valve rod
82
and the valve rod
82
is held so that it can be slid axially for opening and closing the valve.
An end of the valve rod
82
abuts a stopper
84
formed on a frame
83
, whereby the valve
79
is opened against the repulsion force of the spring
81
.
A cleaner holder
87
comprising a wiping member
86
made of a rubber material, for example, that can wipe out the nozzle formation face of the recording head mounted on the carriage accompanying a move of the carriage is placed on the print area side adjacent to the capping unit so that it can be advanced to or retreated from the move path of the recording head.
FIG. 13
shows the cleaning sequence of the recording head in the related art, executed by the described capping unit
71
. The cleaning operation in the recording apparatus in the related art will be discussed according to a flowchart shown in FIG.
13
.
First, when cleaning treatment is started, operation unnecessary for the cleaning treatment, such as paper feed operation, is all inhibited at step S
11
. In this state, the cleaner holder
87
is moved in the horizontal direction and the wiping member
86
is advanced onto the move path of the recording head.
As the carriage is moved, the wiping operation of wiping out the nozzle formation face of the recording head by the wiping member
86
is executed at step S
12
, whereby dust, paper powder, and the like adhering to the nozzle formation face are removed.
Subsequently, the carriage is moved to the capping position and large suction operation of ink from the recording head is executed at step S
13
.
FIGS. 14A
to
14
D schematically show the large suction operation executed at step S
13
and later. In
FIG. 14
, numeral
91
denotes the recording head, numeral
73
denotes the cap member, and numeral
79
denotes the valve connected to the atmosphere port
77
made in the inner bottom part of the cap member by the tube
78
.
Further, numeral
92
denotes the suction pump; waste ink can be discharged into a waste tank
93
through the tube pump
92
connected to the ink suction port
76
made in the inner bottom part of the cap member.
First,
FIG. 14A
shows a state in which the recording head
91
is sealed by the cap member
73
. Subsequently, as shown in
FIG. 14B
, the a
Fukasawa Shigenori
Hayakawa Hitoshi
Seiko Epson Corporation
Sughrue & Mion, PLLC
Tran Huan
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