Ink jet recorder having means for removing unused ink from ink discharge orifice and for capping same

There is disclosed an ink jet recorder having an ink jet record head including an orifice to discharge ink, comprising: a gas jet unit for jetting gas to remove nonused ink discharged from the orifice; and a liquid receptor means for accommodating the removed nonused ink.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an ink jet recorder which discharges ink 
from an orifice and deposits it onto a record medium such as a sheet to 
record data, and more particularly to an ink jet recorder having removal 
means for removing nonused ink discharged from the orifice. 
2. Related Background Art 
An ink jet recorder which discharges ink to record data has been known. 
Such an ink jet recorder usually comprises an ink jet record head having 
an ink discharge function such as a liquid path including an orifice 
through which ink is discharged, discharge energy generation means for 
supplying discharge energy to the ink, and an ink supply system including 
an ink tank from which the ink is supplied to the ink jet record head 
externally of the head. 
In such an ink jet recorder, when an environment in which the recorder is 
used changes or the recorder has not been used for a long time, a 
viscosity of the ink in the liquid path increases or air bubbles are 
generated in the ink supply system, and the ink may not be discharged or 
is hardly discharged. Thus, the ink jet recorder usually has an ink 
recovery system including a liquid seal member such as a cap to prevent 
evaporation of the ink from the orifice during non-record mode in order to 
prevent the viscosity of ink from increasing, and a recirculation pump for 
discharging the high viscosity ink and air bubbles in the liquid path out 
of the liquid path. 
When such an ink recovery system is operated to recover the discharge 
operation in liquid path, nonused ink discharged from the ink jet orifice 
drops along the ink jet record head. If it is left, the vicinity of the 
head is made dirty. Accordingly, an exhaust ink receptacle is provided 
below the ink jet record head or a liquid absorbing material such as 
porous ceramics is provided in the ink jet record head to prevent the 
recorder from being made dirty by the ink. 
However, the exhaust ink dropped through the recovery operation may adhere 
easily to the vicinity of the orifice, and if it is left, the recording 
may not be attained or the quality of the record is degraded. Even if it 
does not adhere, the nonused ink gradually piles up in the vicinity of the 
orifice through long-time use and the piled nonused ink impedes the 
discharge of the ink. Further, dust may deposit onto the nonused ink and 
the discharge of the ink is impeded. The discharge of the nonused ink from 
the orifice may occur by a sudden rise of ambient temperature. Solution 
for the problem relating to the nonused ink has been required. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an ink jet recorder 
which can readily remove nonused ink discharged from an orifice, maintains 
a performance of an ink jet record head throughout a long-time use and 
assures high quality recording over a long period. 
The above object of the present invention is achieved by an ink jet 
recorder having an ink jet record head including an orifice through which 
ink is discharged, the ink jet recorder comprising a gas jet nozzle for 
jetting gas to remove nonused ink discharged from the orifice, and a 
liquid acceptor for accommodating the removed nonused ink.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a sectional view of major portions, among others those around 
an ink jet record head, of one embodiment of the ink jet recorder of the 
present invention. 
In FIG. 1, numeral 1 denotes a known ink jet record head which discharges 
ink from an orifice 3 in accordance with a record signal to record data. 
As shown in FIG. 4, the head 1 is mounted on a carriage which is movable 
in a record direction (main scan direction) on a shaft arranged in 
parallel to a record medium. Numeral 2 denotes a head holder for fixing 
the ink jet record head 1 to the carriage. A desired number of orifices 3 
are usually provided depending on a type of record such as color record. 
In the present embodiment, a plurality of orifices are arranged along a 
length L. When color record is required, three or four record heads 1 may 
be arranged. 
Numeral 4 denotes a cap container which abuts against the head holder 2 in 
a non-record mode and functions as a liquid seal member to define a closed 
space in order to prevent the viscosity of the ink in the ink jet record 
head 1 from increasing by evaporation by performing the capping operation 
so that the periphery of the orifice is tightly sealed. In the present 
embodiment, the cap container 4 is provided with a gas jet nozzle and a 
liquid acceptor in order to remove nonused ink discharged from the 
orifice. FIG. 2 shows a perspective view of a vicinity of the cap 
container 4. 
The cap container 4 includes a liquid absorbing member 5 which serves as 
the liquid accepting means to accommodate the nonused ink discharged from 
the orifice 3. The liquid absorbing member 5 can abut against the orifice 
of the ink jet record head 1 as shown in FIG. 3. Numeral 7 denotes a drive 
transmission mechanism to bring the cap container 4 into contact with the 
record head 1 or move away from the record head. Numeral 6 denotes an 
eject port through which the nonused ink is ejected out of the cap 
container. Numeral 12 denotes a tube through which the ink ejected from 
the eject port 6 is sent to an exhaust ink container 11. In the present 
embodiment, the liquid absorbing material 5 is used as the liquid 
acceptor, although the liquid acceptor may be a receptacle. From a 
standpoint of liquid acceptance efficiency, the liquid absorbing member 5 
made of porous material such as polyvinyl alcohol or polyamide is 
preferable. 
A gas jet nozzle 8 as a gas jet nozzle means is arranged at the top of the 
cap container 4 in a manner to allow gas jetting from the container, and 
blows the nonused ink ejected from the orifice 3 toward the liquid 
absorbing material 5. Numeral 9 denotes an air pump for supplying air to 
be jetted from the gas jet nozzle 8, and numeral 10 denotes a pipe for 
connecting the air pump 9 and the gas jet nozzle 8. In the present 
embodiment, air is used as the jet gas, although it may be N.sub.2 gas. 
The jet gas need not be supplied by the air pump but it may be sent by fan 
motor, blower motor or diaphragm pump. In the present embodiment, the gas 
jet nozzle 8 has a plurality of gas discharge ports, although only one gas 
discharge port may be provided. However, where a plurality of orifices 3 
are arranged in the main scan direction of the ink jet record head, a 
plurality of gas discharge ports corresponding to the plurality of 
orifices are preferably provided in order to properly control the 
direction of flow of the nonused ink. More preferably, the width of the 
gas blown by the gas jet nozzle 8 is wider than the width of array of the 
orifices 3. The gas discharge port may be a slit. 
An operation of the ink jet recorder is now explained. 
In a non-record mode, the cap holder 4 contacts the head holder 2 as shown 
in FIG. 3(a), and the liquid absorbing material 5 shown by broken lines in 
FIG. 3(a) is accommodated in the cap container and the ink jet record head 
1 is shut off to external air by the cap container 4 so that the increase 
of viscosity of the ink is prevented. When a record operation is started, 
or when the ink cannot be discharged by the increased viscosity or 
adherence of the ink or the deposition of dust, the ink recovery operation 
of the record head is carried out. In this case, the cap container 4 
retracts from the position shown in FIG. 3(a) to the position of FIG. 3(c) 
through the position of FIG. 3(b), and the liquid absorbing material 5 
abuts against the head holder 2 while it projects from the cap container 
4. 
In the position shown in FIG. 3(c), the ink is circulated by an ink supply 
circulation device, not shown to eject the increased viscosity ink and air 
bubbles in the ink jet record head from the orifice 3. The nonused ink 
thus ejected drops along the surface of the record head. 
The nonused ink readily adheres to the record head, and if it is left, it 
causes failure of ink discharge and makes the recorder dirty. In the 
present invention, such nonused ink can be readily removed by the gas jet 
nozzle and the liquid acceptor. Simultaneously with the drop of the 
nonused ink, the air pump 9 is started so that air is blown out of the gas 
jet nozzle 8. 
Thus, the nonused ink rapidly drops along the surface of the record head by 
the air flow and is absorbed by the liquid absorbing material 5 which 
abuts against the bottom of the head. Accordingly, in the present 
invention, the nonused ink does not adhere to the surface of the record 
head, and the surface of the head is always kept clean. After the drop of 
the ink has been terminated, the air pump 9 is stopped to terminate the 
ink recovery operation. 
After the recovery operation, the liquid absorbing material 5 is retracted 
as shown in FIG. 3(b), and the carriage 20 is scanned left and right in 
front of the record medium 21 to record data. FIG. 4 shows major portions 
of an embodiment of the ink jet printer having the gas jet nozzle 8 and 
the liquid absorbing material 5. Numeral 20 denotes a carriage which 
carries the ink jet record head held in the head holder 2. The carriage 20 
is slidably arranged on a shaft 22 extending in parallel to a platen 23, 
and it is movable left and right in front of the record medium 21 by a 
belt 26 coupled to a carriage feed motor 25. Numeral 24 denotes a feed 
motor for the record medium 21. 
FIGS. 5(a) and 5(b) show an embodiment of the drive transmission mechanism 
7 which carries out the operation shown in FIGS. 3(a) to 3(c). FIG. 5(a) 
shows a sectional view of the drive transmission mechanism 7 cut along a 
plane parallel to a facing plane of the ink jet record head to the record 
medium, and FIG. 5(b) shows a side view of the drive transmission 
mechanism 7 as viewed from the platen. 
In FIGS. 5(a) and 5(b), the cap container 4 is mounted on a guide 14 which 
is fixed to a frame 13, and is slidable in the direction of the ink jet 
record head. Rack gears 15 and 17 are fixed to the cap container 4 and the 
liquid absorbing material 5, respectively, and the rack gear 17 fixed to 
the liquid absorbing material 5 is slidable in parallel to the cap 
container 4 and the guide 14. Numeral 18 denotes a spur gear for 
transmitting the rotation of the motor 16 to the rack gears 15 and 17. 
In FIGS. 5(a) and 5(b), the cap container 4 is at a position corresponding 
to FIG. 3(b) separated from the ink jet record head. In order to switch to 
the position shown in FIG. 3(c), the motor 16 is rotated to move the cap 
container 4 to the right in FIG. 5(b) and move the liquid absorbing 
material 5 to the left until it abuts against the ink jet record head, and 
then the motor 16 is stopped. In order to switch to the position shown in 
FIG. 3(a), the motor 16 is rotated in the opposite direction until the cap 
container 4 abuts against the ink jet record head, when the motor 16 is 
stopped. 
FIG. 6 shows another embodiment of the ink jet recorder of the present 
invention. In the present embodiment, the gas discharge port of the gas 
jet nozzle 8 is not arranged in cap container 4 as shown in FIG. 1 but is 
arranged externally of the cap container. The same effect as that attained 
in FIG. 1 is offered. 
In the above embodiments, the gas jet nozzle and the liquid acceptor are 
arranged in the cap container which serves as the liquid seal member. The 
present invention is not limited to the illustrated embodiments but the 
gas jet nozzle and the liquid acceptor may be arranged separately from the 
liquid seal member. In this case, a high sealing property in the liquid 
seal member is not required and the object of the present invention may be 
achieved by arranging the gas jet nozzle and the liquid acceptor on a 
support member having an enclosure to prevent nonused ink from scattering. 
The embodiment of the ink jet recorder in which the gas jet nozzle and the 
liquid acceptor are integral with the liquid seal member is most 
preferable because the number of parts required is small and the drive 
mechanism is simple. 
Although, in the above embodiment, the gas jet is executed against the 
orifice 3 under the condition that the recording head is not capped by the 
cap 4, the scope of the present invention is not limited to the above 
embodiment. 
That is to say, in an another embodiment, the gas jet may be executed to 
the orifice 3 with the suction of gas and liquid from the discharge port 6 
under the condition, such as the condition shown in FIG. 3(a), that the 
recording head is capped by the cap 4. In the above another embodiment, 
the undesired ink is smoothly removed because the ink removed from the 
orifice by the gas jet is prevented from scattering outside of the cap 4. 
The ink jet recorder of the present invention has the gas jet nozzle for 
jetting gas to remove the nonused ink discharged from the orifice and the 
liquid acceptor to accommodate the removed nonused ink. Thus, it can 
easily remove the nonused ink from the surface of the ink jet record head 
and accommodates the removed nonused ink in the liquid acceptor. 
Accordingly, the recorder including the ink jet record head is not made 
dirty, the degradation of the record quality by the nonused ink is 
prevented, and high quality of record is assured over a long period. 
In accordance with the present ink jet recorder having the gas jet nozzle 
and the liquid acceptor, the nonused ink discharged from the orifice can 
be rapidly removed without making the recorder dirty. Accordingly, the 
degradation of the quality of record caused by the nonused ink in the 
prior art recorder is prevented, and a high quality of record is assured 
over a long period. Further, maintenance is not required over along-time 
use.