Liquid injection recording apparatus and suction recovery device using capping means integrally provided with a plurality of caps

In a suction recovering device used in a liquid injection recording apparatus having a cap integrally provided with a plurality of caps, each for hermetically sealing the circumference of the orifice of a liquid injection recording head each cap communicating with suction and vent means, the cap is formed of an elastic material and atmosphere communicating means is provided for communicating the interior of the cap with the atmosphere immediately before the circumference of the orifice is hermetically sealed by the cap.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a liquid injection recording apparatus and a 
suction recovering device used in the apparatus. 
2. Related Background Art 
Liquid injection recording apparatus is generally called an ink jet printer 
and is provided with a recording head reciprocally movable along recording 
paper. Liquid is injected from the orifice of the recording head to form 
flying liquid droplets which are used to effect recording. 
When bubbles mix into a liquid flow path provided in the recording head of 
the liquid injection recording apparatus of this type to clog the orifice 
at the end of the liquid flow path or the vicinity thereof, the carriage 
is positioned at a predetermined position which is not opposed to the 
recording surface, for example, a home position, and recording liquid 
(hereinafter referred to as ink) is sucked from the orifice portion by a 
suction recovering device provided on the apparatus side at said position 
to thereby eliminate the bubbles or the clogging. 
Such a suction recovering device has a cap for covering the orifice portion 
of the recording head, and this cap and a pump are connected together by a 
tube and, by driving the pump, ink is sucked from the orifice portion by 
negative pressure. 
In such a suction recovering device, however, the cap is designed to 
hermetically seal the orifice portion and therefore, during the hermetic 
sealing, the pressure in the cap increases to cause retraction of the 
meniscus of the ink in the orifice which in turn causes unsatisfactory 
discharge. 
To eliminate such unsatisfactory discharge, ink must always be sucked in 
the cap, and this leads to wasting ink. 
So, a cap provided with an atmosphere communicating mechanism has been 
proposed and a structure is adopted in which the interior of the cap is 
communicated with the atmosphere during the capping and the communication 
with the atmosphere is broken during the suction. 
Even in such a structure, however, in the case of manual operation, the 
operator may forget to open the portion communicated with the atmosphere, 
and this has led to a problem that during the next capping operation, 
unsatisfactory discharge is caused by the retraction of the meniscus of 
the ink in the orifice. 
In addition to such problem, in the above-described suction recovering 
device according to the prior art, excess ink covers and adheres to the 
orifice portion when ink is sucked from the orifice portion by negative 
pressure and during ink discharge, the presence of such adhering ink 
causes very unstable discharge. 
It has also been proposed to provide an ink absorber in the cap and urge 
this absorber against the portion in which the orifice is disposed, to 
thereby suck and eliminate the adhering ink. However, if such a structure 
is adopted, there will occur the possibility of air being forced back into 
the orifice, which will further result in displacement of dust adhering to 
the absorber toward the orifice portion, which in turn will rather cause 
unsatisfactory discharge. 
Also, the recording medium may be stained by excessive ink during the 
opening of the cap. 
Further, in the suction recovering device, during the initial supply of ink 
and during the supply of ink when the ink tank has become empty, the ink 
suction operation positively directs the ink to the recording head side 
and therefore, unlike the normal discharge recovery time, a great amount 
of ink is sucked. 
In order to increase the amount of ink sucked during such initial supply of 
ink, the suction pump has been of a great capacity, but this has also led 
to a disadvantage that the suction mechanism becomes so bulky as to 
prevent the device from being compact and the amount of ink sucked during 
the normal recording is so great as to cause wasting ink. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a liquid injection 
recording apparatus which solves the above-noted problems peculiar to the 
apparatus according to the prior art and a suction recovering device used 
in such apparatus. 
It is another object of the present invention to provide a liquid injection 
recording apparatus provided with a suction recovering device having a cap 
for hermetically sealing the circumference of the orifice of a liquid 
injection recording head, said cap being formed of an elastic material, 
said apparatus having communicating means for communicating the interior 
of the cap with the atmosphere immediately before the circumference of the 
orifice is hermetically sealed by said cap. 
It is still another object of the present invention to provide a liquid 
injection recording apparatus provided with a suction recovering device 
for hermetically sealing the circumference of the orifice of a liquid 
injection recording head by a cap and effecting the suction recovery of 
recording liquid by negative pressure, the apparatus being provided with 
operating means for operating negative pressure generating means 
generating the negative pressure when said cap is fitted to said liquid 
injection recording head. 
It is yet still another object of the present invention to provide a 
suction recovering device for hermetically sealing the circumference of 
the orifice of a liquid injection recording head by a cap and effecting 
the suction recovery of recording head by negative pressure, the device 
being provided with operating means for operating negative pressure 
generating means generating the negative pressure when said cap is fitted 
to said liquid injection recording head. 
It is a further object of the present invention to provide a suction 
recovering device used in a liquid injection recording apparatus wherein 
the circumference of the orifice of a liquid injection recording head is 
hermetically sealed by a cap and the suction recovery of recording liquid 
is effected by negative pressure, said device being provided with control 
means for controlling the amount of negative pressure generated. 
It is still a further object of the present invention to provide a suction 
recovering device for a liquid injection recording apparatus in which 
during normal state including the ON and OFF states of the power source of 
the apparatus body, the circumference of the orifice of a recording head 
is not hermetically sealed but capped in the atmosphere-communicated state 
to thereby prevent air from being forced into the recording head and 
stabilize the quality of printing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
First Embodiment 
FIGS. 1 to 3 illustrate an embodiment of the present invention, and in FIG. 
2, there is shown an example of the liquid injection recording apparatus 
to which the present invention is applied. 
In FIG. 2, reference numeral 1 designates recording heads each having an 
ink storing portion for storing therein ink supplied from an ink supply 
source, a flow path for injecting the stored ink and an orifice formed at 
the end of the flow path, and provided with energy generating means for 
injecting the ink, for example, an energy converting member comprising a 
piezoelectric element which is an electro-mechanical converting members or 
a heat-generating resistance member which is an electro-mechanical 
converting members. 
The number of the recording heads 1 is one in the case of monochromatic 
recording, but is four, for example, in conformity with the colors of ink 
in the case of color recording. 
These recording heads 1 are mounted on a carriage 2 which is provided for 
sliding movement along two guide shafts 18. 
The recording heads 1 and the carriage 2 are connected together by flexible 
cables 6 through which a control signal is supplied to the recording 
heads. 
The carriage 2 is fixed to the intermediate portion of an endless belt 14 
which is driven by a motor 16 to reciprocally move the carriage 2. 
Two sets of rollers 10, 10 and 12, 12 are provided in parallelism to the 
guide shafts 18 and in opposed relationship with the carriage 2, and 
recording paper P is guided between these rollers. 
A paper feeding motor 8 is fixed to one end of one of the rollers 10 to 
feed the recording paper P. 
On the other hand, a suction recovering device 20 is provided at a home 
position indicated by H. 
This suction recovering device 20 is of a structure as shown in FIGS. 1 and 
3. 
That is, the suction recovering device 20 is assembled with a base plate 
20a as a standard, and a motor 25 is fixed to a portion thereof. 
A pinion gear 25a fixed to the output shaft of the motor 25 is in mesh 
engagement with a gear 25b, and a pinion gear, not shown, which is 
integral with the gear 25b is in mesh engagement with a gear 25c. 
A pinion gear 25d fixed to the rotary shaft of the gear 25c is in mesh 
engagement with a gear 24. 
Two trapezoidal cams 24a circumferentially spaced apart from each other by 
a predetermined angle are projectedly provided on the upper surface of the 
gear 24. 
Designated by 29 is a pump lever having its intermediate portion pivotally 
supported on a support frame 29a through a shaft 29b, the support frame 
29a being projectedly provided on a base plate. 
One end of the pump lever 29 is provided with a roller 29c for riding onto 
the cams 24a projectedly provided on the gear 24 and the other end of the 
pump lever 29 is in contact with the piston 26a of a pump 26 through a 
projection 29d. 
This piston 26a is normally biased into its extended position by a spring 
provided in the pump to normally bring the roller 29c into contact with 
the gear 24. 
Denoted by 21 is a cap holder to which are fixed a plurality of caps 
22a-22d formed of an elastic material such as rubber. 
Each of the caps 22a-22d is provided with an ink absorber 37 below the 
inner side thereof, and these caps are discretely connected to the pump 26 
through tubes 27a-27d. 
The cap holder 21 is slidably provided on the base plate 20a and is 
normally biased away from the pump 26 by a spring, not shown. 
A gear 23 is rotatably journalled to the underside of the cap holder 21. 
An inner face cam 23a is formed on the upper surface of the gear 23, and a 
shaft 21a projected from the lower end of the cap holder 21 is in contact 
with the inner face cam 23a through a roller. 
Accordingly, the cap holder 21 repeats the operation of being pushed back 
toward the pump 26 by the protruding portion of the cam 23a with rotation 
of the gear 23. 
The position of the cap holder 21 is detected by a switch 31. 
On the other hand, the caps 22a-22d have ink sucking tubes 27a-27d and vent 
tubes 28a-28d. 
Each of the vent tubes 28a-28d has its end connected to an electromagnetic 
valve device 32. 
Within the electromagnetic valve device 32, a support frame 33 is fixed as 
shown in FIG. 3, and one end of each of the vent tubes 28a-28d is 
connected to the support frame 33 and is exposed to the atmosphere. 
A solenoid 34 is provided in juxtaposed relationship with the support frame 
33 and the rod 34a thereof faces the support frame 33, and a valve 35 for 
closing the open ends of the vent tubes 28a-28d is fixed to the end of the 
rod 34a. 
Designated by 36 is a return spring. 
The operation of the present embodiment constructed as described above will 
now be described. 
All control operations are performed while the gear 24 makes one full 
rotation from the cap open state, i.e., the state in which the caps 
22a-22d are spaced apart from the nozzle portions of the recording heads 
and recording is possible. 
That is, the gear 23 also makes one full rotation while the gear 24 makes 
one full rotation, and almost in the meantime, the caps are fitted 
(closed) to the nozzle portions and this state is detected by a switch 31 
for detecting the opening-closing of the caps. 
The caps are fitted to the nozzle portions in a state in which the solenoid 
34 is not operated and the open ends of the vent tubes 28a-28d are not 
closed (the venting state). 
Subsequently, when the solenoid 34 is operated and the venting state is 
closed by the valve 35, the roller 29c of the pump lever 29 rides onto the 
cam 24a with the aid of the rotation of the gear 24 and the pump lever 29 
is pivotally moved counter-clockwise as viewed in FIG. 1, and the first 
suction operation by the pump 26 is performed. 
Subsequently, the power supply to the solenoid 34 is cut off and the valve 
35 is retracted to bring about the venting state and in this state, the 
roller 29c of the pump lever 29 rides onto the other cam 24a and the 
second pump suction operation is performed. 
This is the so-called idle suction, and the excess ink sucked into the caps 
22a-22d is sucked toward the pump with the air in the vent tubes 28a-28d. 
During the idle suction operation, the ink retained by the ink absorbers 37 
in the caps and the ink adhering to the ends of the nozzles are sucked 
toward the pump at the same time. 
The normal cap opening-closing operation is automatically effected by a 
timer for the purpose of preventing the drying of the nozzle portions and 
the adherence of dust thereto, and in a case where recording is not 
effected for a predetermined time, idle suction is executed in the venting 
state. 
On the other hand, when the main switch has been closed during the normal 
use, after the non-recording state has continued for a predetermined time, 
ink is sometimes discharged preparatorily to provide a proper ink 
discharging state and in such case, the amount of ink in the caps becomes 
excessive and the ink adheres to the ends of the nozzles to cause unstable 
discharge or the recording paper is stained by the dripping of the excess 
ink when the caps are opened. 
In order to prevent this, the idle suction in the venting state as 
previously described is effected by a command from a control device, not 
shown, to thereby stabilize the discharge of ink. 
Also, the opening-closing of the caps is effected always in the venting 
state and therefore, the retraction of the meniscus of the nozzles 
resulting from the increase in the air pressure during the capping 
operation can be prevented. 
Second Embodiment 
The above-described embodiment has exemplarily shown the suction recovering 
device for the multinozzle type liquid injection recording apparatus, 
while FIGS. 4 and so on show a suction recovering device wherein the 
number of the nozzles of the recording head is one. 
In FIG. 4, reference numeral 41 designates a motor as the drive source of 
the suction recovering device. The revolution of this motor 41 may be 
transmitted to a cam gear 42. Reference numeral 44 denotes a cap which 
becomes opposed to the liquid injection recording head when the carriage 
mounting the recording head thereon is positioned in the home position H. 
The cap 44 has an absorber 44a formed, for example, of a water-absorbing 
porous material and joined to the nozzle portion which is the end portion 
of the recording head. 
The cap 44 has connected thereto one end of an atmosphere opening tube 45 
for letting the pressurized air in the cap escape outwardly when the 
nozzle portion is hermetically sealed, and a portion of the atmosphere 
opening tube 45 is open to the atmosphere. The opening 45a (see FIG. 6) of 
the atmosphere opening tube 45 is designed to be opened and closed by the 
cam surface portion 46a of an operating lever 46 through a vent valve 47. 
The vent valve 47 is supported on a support shaft 49 fixed to a support 
bracket 48 and is normally biased upwardly by a spring 50. Accordingly, 
when no extraneous force is applied to the vent valve 47, the opening 45a 
of the atmosphere opening tube 25 remains open (open to the atmosphere). 
Also, as is apparent from FIGS. 5 and 6, the intermediate portion of the 
atmosphere opening tube 45 is open to the atmosphere and the opening 51a 
of a valve seat portion 51 connected to the opening 45b at the other end 
of the tube 45 is designed to be opened and closed by the valve portion 
52a of an electromagnetic valve 52. That is, when the electromagnetic 
valve 52 is energized, the opening 51a is opened to the atmosphere, and 
when the electromagnetic valve 52 is deenergized, the opening 51a is 
closed. Also, the electromagnetic valve 52 is designed to be energized 
after the lapse of a predetermined time after a pump driving switch has 
been closed, so that the opening 51a of the valve seat portion 51 is 
opened to the atmosphere so as to permit the air to be supplied into the 
atmosphere opening tube 45 when the pressure in a pump 56 is negative. 
Accordingly, even after the pump suction operation (after the negative 
pressure suction), the interior of the atmosphere opening tube 45 can be 
maintained in the atmospheric pressure condition and the flow of the ink 
into the atmosphere opening pipe 45 can be eliminated. Consequently, 
during automatic capping, unsatisfactory discharge resulting from the 
retraction of the meniscus of the nozzle by the resistance of the liquid 
film in the atmosphere opening tube as experienced in the prior art can be 
reliably avoided. 
Further, in order to prevent unsatisfactory discharge, the electromagnetic 
valve 52 at the distal end of the atmosphere opening tube 45 is energized 
before the capping to thereby open the tube 45 to the atmosphere. 
As a result, a good discharge state can be secured even if the operator 
forgets to open the operating lever 46. 
Also, even if the electromagnetic valve 52 is deenergized after the cap has 
been closed, retraction of the meniscus of the nozzle will not take place. 
On the other hand, the operating lever 46 is supported on a support member 
54 by a pin 53 and is pivotable about the pin 53. By pushing up the 
operating portion 46b of the operating lever 46 in the direction of arrow 
A from the position of FIG. 4, the opening 45a at the distal end of the 
atmosphere opening tube 45 becomes open to the atmosphere, while on the 
other hand, by depressing the operating portion 46b in the direction of 
arrow B, a piston 55 is urged by the protrusion 46c of the operating 
portion 46b and thus, pump suction operation is performed. A spring (not 
shown) for biasing the piston 55 upwardly is contained in a pump 56 which 
is connected to the cap 24 through a suction tube 57. That is, in response 
to the driving of the pump 56, ink is sucked from the nozzle portion 
through the absorber 44a and is further directed to the pump 56 through 
the suction tube 57 (see FIG. 4). 
Thus, even in a case where the number of nozzles is one, if the 
electromagnetic valve provided at one end of the tube communicating with 
the atmosphere is operated and is opened to the atmosphere immediately 
before capping is effected, the retraction of the meniscus of the nozzle 
by the increase in the pressure in the cap will be prevented, and by the 
negative pressure suction operation being operatively associated with the 
electromagnetic valve, formation of a liquid film in the atmosphere 
opening tube can be avoided to stabilize ink discharge. 
Third Embodiment 
A third embodiment of the suction recovering device 20 is shown in FIGS. 7A 
and 7B. 
The suction recovering device 20 is assembled with a base plate 720a as a 
standard, and a motor 725 is fixed to a portion thereof. 
A pinion gear 725a fixed to the output shaft of the motor 725 is in mesh 
engagement with a gear 725b, and a pinion gear, not shown, which is 
integral with the gear 725b, is in mesh engagement with a gear 725c. 
A pinion gear 725d fixed to the rotary shaft of the gear 725c is in mesh 
engagement with a gear 724b. 
A first cam plate 724 is integrally fixed to the gear 724b, and between the 
first cam plate 724 and the gear 724b, a second cam plate 719 is fixed 
coaxially with the gear 724b. 
Two trapezoidal cams 724a circumferentially spaced apart from each other by 
a predetermined angle are projectedly provided on the upper surface of the 
first cam plate 724. 
Also, a cam position 724d which constitutes a vent opening-closing portion 
in a symmetrical state is projectedly provided on the peripheral surface 
of the first cam plate 724. 
A cam portion 724c is projectedly provided on the peripheral surface of the 
second cam plate 719 also and may be detected by a detecting switch 730 
comprising a microswitch or the like. 
Designated by 729 is a pump lever having its intermediate portion pivotally 
supported on a support frame 729a projectedly provided on the base plate, 
through a shaft 729b. 
One end of the pump lever 729 has provided thereon a roller 729c for riding 
onto the cam 724a projectedly provided on the first cam plate 724, and the 
other end of the pump lever 729 is in contact with the piston 726a of a 
pump 726 through a projection 729d. 
The piston 726a is normally biased into its extended position by a spring 
provided in the pump and normally forces the roller 724c into contact with 
the first cam plate 724. 
Denoted by 721 is a cap holder having fixed thereto a plurality of caps 
722a-722d formed of an elastic material such as rubber. 
An ink absorber 737 is provided in the lower portion of each of the caps 
722a-722d, and these caps are discretely connected to the pump 726 through 
tubes 727a-727d. 
The cap holder 721 is slidably provided on the base plate 720a and is 
normally biased away from the pump 726 by a spring, not shown. 
A gear 723 is rotatably supported under the cap holder 721. 
An inner face cam 723a is formed on the upper surface of the gear 723, and 
a shaft 721a projected from the lower end of the cap holder 721 is in 
contact with the inner face cam 723a through a roller. 
Accordingly, with rotation of the gear 723, the cap holder 721 repeats the 
operation of being pushed back toward the pump 726 by the protrusion of 
the cam 723a. 
The position of the cap holder 721 is detected by a switch 731. 
On the other hand, the caps 722a-722d have ink sucking tubes 727a-727d and 
vent tubes 728a-728d. 
The other end of each of the vent tubes 728a-728d is fixed to a support 
frame 721b through a rubber plug 732, the support frame being integral 
with the cap holder 721 and located between the cap holder and the first 
cam plate 724, as shown in FIG. 8. 
Also, a pivotable lever 735 has its upper end pivotally supported on the 
upper end of the support frame 721b through a shaft 736. 
The lower end of the pivotable lever 735 is opposed to the first cam plate 
724 and has a plug 733 at a position opposed to the rubber plug 732. 
The pivotable lever 735 is urged toward the first cam plate 724 by a return 
plate 735a, and the plug 733 is urged toward the rubber plug 732 by a 
spring 733a and the movement thereof is controlled by a stopper 733b. 
The operation of the present embodiment constructed as described above will 
now be described with reference to the timing chart of FIG. 9. 
FIGS. 9(A)-(I) illustrate the operation timings of the respective switches, 
cams and other members, and as can be seen therefrom, all control 
operations are effected while the first and second cam plates 724 and 719 
make one full rotation from the cap open state, i.e., the state in which 
recording is possible with the caps 722a-722d being spaced apart from the 
orifice portion of the recording head, not shown. 
That is, the gear 723 also makes one full rotation while the first and 
second cam plates integral with the gear 724b make one full rotation, and 
almost in the meantime, the caps are in their closed state as shown in 
FIG. 9(A) and the switch 731 for detecting the opening-closing of the caps 
is in its OFF position as shown in FIG. 9(E). 
The caps are secured over the orifice portion in a state in which the cam 
portion 724a is not in contact with the pivotable lever 735, that is, a 
state in which the tubes 728a-728d are in their venting state. 
In a state in which as shown in FIG. 9(C), the vent is closed, that is, a 
state in which the cam portion 724d pushes the pivotable lever 735 and the 
rubber plug 732 is closed by the plug 733, the roller 729c of the pump 
lever 729 rides onto the cam 724a and the pump lever 729 is pivoted 
counter-clockwise as viewed in FIG. 7A, whereby the first suction 
operation by the pump 726 is effected. This state is shown in FIG. 9(D). 
Soon, the cam portion 724a becomes separate from the pivotable lever 735 
and, when the vent tubes 728a-728d become vent-open, the roller 729c of 
the pump lever 729 rides onto another cam 724a, whereby the second pump 
suction operation is effected. 
This is the so-called idle suction, and the excess ink sucked into the caps 
722a-722d is sucked into the pump with the air in the vent tubes 
728a-728d. 
As shown in FIG. 9(B), the discharge port for waste ink (designated by 734 
in FIG. 7A) is in its discharging-capable state during the suction 
operation. 
During the idle suction operation, both the ink retained in the ink 
absorber 737 in the caps and the ink adhering to the end of the orifice 
are sucked into the pump at the same time. 
The normal cap opening-closing operation shown in FIG. 9(G) is 
automatically effected by a timer for the purpose of preventing drying of 
the orifice portion and the adherence of dust thereto, and is performed as 
idle suction in the venting portion in a case where recording is not 
effected for a predetermined time. Thereafter, the caps are moved by a 
recording command as indicated by dotted line in FIG. 9(G) and are opened, 
thereby bringing about the recording condition. 
On the other hand, when the main switch has been closed during the normal 
use, after the non-recording state has continued for a predetermined time, 
ink is sometimes discharged preparatorily into the caps to provide a 
proper ink discharge state, but in such case, the amount of ink in the 
caps becomes excessive and ink adheres to the end of the orifice to render 
the discharge unstable and the recording paper is stained by dripping of 
excessive ink when the caps are opened. 
In order to prevent this, the idle suction in the venting state as 
previously described is effected by a command from a control device, not 
shown, to thereby stabilize the ink discharge. 
Also, the opening-closing of the caps takes place always in the venting 
state and therefore, the retraction of the meniscus of the orifice 
resulting from the rise of the air pressure during the capping operation 
can be prevented. 
The suction recovering operation in the normal state as described above is 
the operation "I" shown in FIG. 9(H). 
On the other hand, when the operation of sucking a great amount of ink at 
the initial stage of ink supply is to be effected, the suction operation 
"II" shown in FIG. 9(J) is performed. 
That is, suction of a great amount of ink can be accomplished if the 
forward and reverse revolutions of the motor 725 are repeated between the 
hermetically sealed position A and the suitable position B of the 
vent-closed state and the pump lever 729 is pivoted a plurality of times 
to operate the pump 726 a plurality of times. 
This operation may be effected by a timer with the point A as the 
reference. 
For the setting of the point B, a switch may be provided, but to make the 
apparatus compact, timer control will suffice and it will be unnecessary 
to provide any special switch. 
In this manner, the amount of negative pressure generated is controlled by 
the frequency of driving of the negative pressure generating source, 
whereby a large volume of negative pressure can be generated by a negative 
pressure generating source of small capacity. 
Forth Embodiment 
FIGS. 10 and 11 shows an example of the suction recovering device for 
multiple colors as the suction recovering device 20. In FIGS. 10 and 11, 
reference numeral 1021 designates a cap member adapted to become opposed 
to the liquid injection recording unit 1 when the carriage 2 is positioned 
in the home position H. This cap member 1021 is provided with a cap holder 
1022, a cap slider 1023 disposed in the cap holder 1022 for forward and 
backward movement (in the directions of arrows A and A') and having 
attached to the rear end portion thereof a stopper ring (not shown) 
adapted to bear against the rear end surface of the cap holder 1022 and 
control any further forward movement thereof, a rubber member 1025 
disposed in the forward end opening in the cap slider 1023 and keeping an 
internal space 1024, defined by the cap slider and the liquid injection 
recording unit, air-tight in the state in which it is joined with the unit 
1, vent holes 1026 provided so as to extend through the upper portions of 
the cap slider 1023 and cap holder 1022 and formed so as to always open 
the internal space 1024 to the atmosphere, absorbers 1027 formed of a 
water-absorbing porous material, for example, and disposed in the lower 
portion of the rubber member 1025 and joined to the nozzle portion, and a 
compression spring 1028 interposed between the cap holder 1022 and the cap 
slider 1023 and adapted to be compressed by a pressure force when the 
rubber member 1025 is pressed rearwardly. 
Reference numeral 1029 denotes a vent opening-closing lever pivotally 
supported on a lever shaft 1030 and opening and closing the vent holes 
1026. Rubber members 1029A corresponding to the vent holes 1026 and 
opening and closing these vent holes are provided on the underside of the 
fore end of the vent opening-closing lever 1029. The vent opening-closing 
lever 1029 is normally biased counter-clockwise (in a direction to close 
the vent hole 1026) by a return spring 1032 interposed between the rear 
end thereof and a base plate 1031. Reference numeral 1033 designates a 
lock member pivotally supported on a shaft 1034 and formed substantially 
in the shape of a crank. The upper end portion 1033A of this lock member 
1033 is formed for engagement and disengagement with the rear end portion 
of the vent opening-closing lever 1029 (dots-and-dash line 1033' indicates 
the disengaged state), and the lower end portion 1033B of the lock member 
1033 is in engagement with the cam surface 1035A of a vent cam 1035 and is 
designed to be operated following this cam surface 1035A. A lock member 
spring 1036 is extended between the upper end portion 1033A of the lock 
member 1033 and the base plate 1031, and the lock member 1033 is normally 
bised counter-clockwise (in a direction in which the upper end portion 
1033 of the lock member 1033 tries to engage the rear end portion of the 
vent opening-closing lever 1029) by the resiliency of the lock member 
spring 1036. 
Although not shown, a cap opening switch and a cap closing switch adapted 
to be actuated by the cam surface 1035A of the vent cam 1035 are provided 
at predetermined locations on the cam surface 1035A. These cap opening and 
cap closing switches are designed such that as shown in FIG. 12, the cap 
closing switch is closed after the lapse of a predetermined time 
(TC.sub.1) after the cap opening switch is opened. 
Further, a cam surface 1035B is provided also on the upper portion of the 
vent cam 1035, and a suction recovering operation lever (not shown) for 
driving a pump (not shown) is designed to be operated following the 
displacement of this cam surface 1035B. The vent cam 1035 is rotatably 
supported on a shaft 1037 and is designed to be rotated by the revolution 
of a drive motor, not shown, being transmitted to a gear portion 1035C 
through a gear train. The pump and the cap member 1021 are connected 
together through a suction tube (not shown) so that in response to the 
driving of the pump, ink is sucked from the nozzle portion through the 
absorbers 1027 and is further directed to the pump through the suction 
tube. 
FIG. 12 shows the operation timings of the various portions of the suction 
mechanism. In FIG. 12, the displacement curve (A) of the cap member 1021 
and the curve (B) indicating the operation of the pump correspond to the 
outline curves, respectively, of the cam surface of a cam for moving the 
cap member forward and backward and the cam surface 1035B of the vent cam 
1035. 
Also, the period T corresponds to one full rotation (360.degree.) of the 
cam for moving the cap member forward and backward and of the vent cam 
1035. 
In FIG. 12(A), the period TA.sub.1 is a period during which cap member 1021 
is moved toward the nozzle portion in response to the rotation of the cam 
for moving the cap member forward and backward. In the process of this 
movement, the cap opening switch is opened as shown in FIG. 12(C), and 
further, the cap closing switch is closed in a predetermined time 
(TC.sub.1) after the cap opening switch has been opened. 
The period TA.sub.2 is a period during which the cap member 1021 is in 
contact with the nozzle portion and the flowpath of ink from the nozzle 
portion to the pump is opened. Also, at a time T.sub.1, driving of the 
pump is effected by the displacement of the cam surface 1035B of the vent 
cam 1035. In one stroke comprising a period TB during which the suction 
discharge operation from the time T.sub.1 is effected, the cap member 1021 
is closed and therefore, the ink from the nozzle portion is sucked and 
discharged into a waste ink receiving portion. Also, the period TA.sub.3 
after such suction and discharge is a period during which the cap member 
1021 becomes separate from the carriage 2 side, and in this process of 
separation, the cap opening switch is closed. 
The vent cam 1035, as shown in FIG. 12(E), maintains its closed state (that 
is, the state in which) the vent hole 1026 is closed) only before and 
after the pump suction operation (the suction recovering operation) is 
effected after the caps have become hermetically sealed, and is in its 
opened state (the state in which the vent hole 1026 is opened) at other 
times. 
In FIG. 12(F), S.sub.1 indicates the hermetically sealed cap position when 
the drive motor is revolved, for example, in a forward direction, and 
S.sub.2 indicates the atmosphere communicated cap position when the drive 
motor is revolved in a reverse direction. Upon arrival of a cap opening 
signal such as a print signal, the drive motor revolves in a forward 
direction and print becomes possible with the cap opening switch being 
closed. Also, upon arrival of a suction signal and only when the drive 
motor is stopped at a position specially indicated during transportation, 
the vent cam closed state is brought about and the vent cam 1035 moves in 
the direction of 0.degree..fwdarw.360.degree. during the suction recovery 
until the cap opening switch is closed. The vent cam 1035 moves in the 
range of the detected position of S.sub.2 and 360.degree. during the 
normal capping operation.