Ink jet printer

An ink jet printer includes an ink jet head having nozzles, which can be covered with a suction cap. A pump can suck ink out of the head to purge it. A controller can vary the suction pressure or the suction cycle period of the pump in accordance with a purge mode. Automatic purges can be performed at predetermined time intervals for the maintenance of the printer. A manual purge can be performed for recovery from defective ejection of ink from the head. Another purge can be performed just after an ink cartridge is replaced for the printer. The controller controls the pump in such a manner that at least one of the automatic purges, the manual purge and the purge after cartridge replacement differ from each other in at least one of the suction period and pressure. Depending on the using condition of the printer, it is possible to prevent defective ejection of ink due to the clogging of the nozzles and/or the bubbling of ink.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a recovery apparatus for an ink jet 
printer for recording by ejecting ink onto a recording medium. 
2. Description of Related Art 
A conventionally known ink jet printer includes a recording head for 
recording by ejecting ink onto a recording medium. The printer also 
includes a pumping means having a suction cap for contact with a surface 
of the head on which nozzles are formed. The pumping means can suck ink 
from the head through the cap in contact with the nozzle formed surface. 
The printer further includes a control means for controlling the operation 
of the pumping means. The pumping means is controlled by the control means 
to perform a suction action. In general, this action develops a high 
negative pressure for suction to suck ink from the recording head in a 
dash through the suction cap. 
For example, after an ink cartridge is connected to the recording head for 
the first time, or after the cartridge is replaced with a new one, the ink 
passage between the head and the cartridge may be filled with air. In such 
a case, if great suction force is applied through the suction cap, as is 
the case with a normal purge for recovery from defective ejection during 
recording operation, to suck ink from the head in a dash, a mixture of ink 
and air flows rapidly from the cartridge toward and into the head. The 
rapidly flowing ink bubbles, and consequently the ink in the ejection 
channels of the head contains air bubbles. In particular, this tendency is 
remarkable if a filter is fitted between the head and the cartridge to 
keep foreign substances etc. from moving together with ink toward the 
head. The filter may cover the ink supply hole of the cartridge. 
Therefore, for example, after the cartridge is replaced, it is demanded 
that ink be sucked from the recording head without bubbling as stated 
above. 
On the other hand, when the ejection from the nozzles of the head is 
defective or bad with dry ink, foreign substances or the like blocking the 
nozzles, it is preferable that ink be sucked from the head in a dash with 
high negative pressure. 
Automatic suction is performed depending on the length of the nonuse period 
with a timer fitted in the printer. This suction involves only removing 
the drying ink from the nozzles with relatively low negative pressure. 
As the pump means, U.S. Pat. No. 5,639,220 of the assignee of the present 
applicant discloses a suction pump having a pump body provided with a 
suction port and a discharge port which are axially spaced, and a first 
piston and a second piston slidably fitted in the pump body to form a 
suction chamber therebetween. In a operation, a driving mechanism of the 
pump moves the first piston away from the second piston to expand the 
suction chamber so that negative pressure prevails in the suction chamber 
and ink is suctioned through the suction port into the suction chamber. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide an ink jet printer recovery 
apparatus which can change the form of ink suction depending on the 
condition of the nozzles in the recording head and/or the ink passage. In 
accordance with the invention, an ink jet printer is provided, which 
includes an ink jet head having nozzles for ejecting ink, a suction cap 
for covering the nozzles, and a pump for sucking ink out of the head 
through the cap to purge the head. The printer further includes a 
controller. When a purge is performed, the controller controls the pump 
depending on the condition of the printer to adjust at least one of the 
suction cycle period and the suction pressure applied to the cap. 
The nozzles of the ink jet head are purged by the pump sucking ink out of 
them with the suction cap capping the head. When the nozzles are purged, 
it is possible to suitably adjust the suction cycle period or the suction 
pressure applied to the cap. It is therefore possible to perform a purge 
which is suitable for the condition of the printer, and in particular of 
the nozzles and/or the ink passage. 
Automatic purges may be performed at predetermined time intervals for the 
maintenance of the printer. A manual purge may be performed for recovery 
from defective ejection of ink from the ink jet head. Another purge may be 
performed just after the replacement of an ink cartridge for the printer. 
The pump may be controlled in such a manner that at least one of the 
automatic purges, the manual purge and the purge after cartridge 
replacement differ from each other in at least one of the suction cycle 
period and the suction pressure. 
For example, the controller may control the pump in such a manner that the 
suction pressure is lower for the automatic purges than for the manual 
purge. In this case, the manual purge enables the ink jet head to recover 
from defective ejection of ink due to the clogging of the nozzles or the 
like. On the other hand, the automatic purges can prevent the head from 
ejecting ink defectively due to the bubbling of ink. The controller may 
also control the pump in such a manner that, for the purge just after 
cartridge replacement, the suction pressure is lower than for the 
automatic purges. In this case, the head can be prevented from ejecting 
ink defectively due to the bubbling of ink just after an ink cartridge is 
replaced for the printer. 
The purge just after cartridge replacement may involve a suction action 
with smaller suction force and for a shorter time than the manual and 
automatic purges. In this case, ink can be sucked together with the air 
which is present between the substituted cartridge and the ink jet head, 
and the ink can be prevented from bubbling there. This secures good 
ejection after cartridge replacement. 
In particular, the purge just after cartridge replacement may involve a 
plurality of suction actions with small suction force and each for a short 
time and, thereafter, a suction action with great suction force and for a 
long time. The earlier actions with small suction force expel air 
gradually out of the ink passage, and then fill the passage with ink. The 
subsequent action with great suction force securely provides a good 
condition for starting the ejection. The pump may perform a first suction 
action and a second suction action which is greater in suction force and 
longer in suction time than the first action. The first action may be 
omitted during each of the automatic and manual purges. This can prevent 
ink from being wasted during the automatic and manual purges, and shorten 
the purge time. 
The printer may also include a memory storing various suction modes, which 
are combinations of suction pressures and suction cycle periods. In this 
case, when a purge is performed, the controller may select the suction 
mode depending on the printer condition. In accordance with the selected 
mode, the controller may operate the pump. 
The printer may further include a switch for performing the operator's 
manual purge, a timer, and/or a sensor for detecting the replacement of an 
ink cartridge. The suction modes may include a mode of performing the 
manual purge on the basis of the operator's switching operation, a mode of 
performing automatic purges at time intervals predetermined by the timer, 
and/or a mode of performing a purge just after replacement of an ink 
cartridge in accordance with a detection signal from the sensor. 
The pump may include a pump body, which has a suction port and a discharge 
port both formed in it. The pump may also include a pair of pistons, which 
can slide in the body, and which define a pump chamber between them in the 
body. At least one of the pistons can close and open at least one of the 
ports when the one of the pistons slides. A cam may be connected to the 
pistons to drive them. 
The movement of the pistons may be controlled to vary the volume of the 
pump chamber between them, adjusting the suction pressure and/or the 
suction cycle period. For example, the suction pressure and/or the suction 
cycle period may be adjusted by moving the pistons continuously without 
stopping them, or by moving the pistons intermittently, with the suction 
port open. This intermittent movement may include stopping temporarily and 
then moving again. Otherwise, the suction pressure and/or the suction 
cycle period may be adjusted by varying the cycle period of the 
intermittent movement, or by adjusting the time for which the pistons 
stop. 
The cam may have cam grooves of predetermined patterns. The grooves may 
each engage with a cam follower, which may be connected to one of the 
pistons. The grooves may have profiles for driving the pistons 
independently of each other. This can achieve complex suction patterns, in 
each of which the suction form varies with the turning angle of the single 
cam. The suction port may be opened a plurality of times during one turn 
of the cam. While the suction port is open, the cam may be turned 
continuously or intermittently to move the pistons continuously or 
intermittently, thereby adjusting the suction pressure and/or the suction 
cycle period. By thus adjusting the turning and the stopping of the cam, 
it is possible to make the suction pressure variable without varying the 
turning speed of the cam, that is to say, without using a varying-speed 
motor, which is complicated and expensive. However, the turning speed of 
the cam might be adjusted to produce various suction modes. 
The suction cap may include a member having a cam follower for engagement 
with the cam. The cam can, through the member, move the suction cap toward 
and away from the ink jet head. This can make common the drive sources for 
the cap and the pump to make the printer small. In this case, by adjusting 
the position of the cap relative to the head and the suction timing, it is 
possible to suck ink together with air, with the cap separated partially 
from the surface of the head in which the nozzles are formed. This can 
suck and remove the ink remaining in the cap.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
With reference to FIG. 1, an ink jet printer 1 according to the invention 
includes a frame 2, a sheet cassette (not shown) or a manual feed port 
(not shown) and a sheet outlet (not shown). A sheet feed mechanism LM 
includes a cylindrical platen roller 3 supported rotatably by the frame 2 
through a horizontal shaft (not shown). A printing sheet or recording 
medium 4 can be fed from the cassette or the feed port, and moved under an 
ink jet type recording head 5 by the roller 3. The head 5 has nozzles for 
ejecting droplets of ink onto the sheet 4 to print it. The feed mechanism 
LM also includes a sheet feed motor (LF motor) 14 (FIG. 5) for driving it 
to move the sheet 4. 
A printing sheet 4 can be fed in the direction A from the cassette or the 
feed port in a rear portion of the frame 2, and then turned in the 
direction B by the rotation of the platen roller 3. The turned sheet 4 can 
be discharged in the direction C from the outlet. In front of the platen 
roller 3, a carriage 6 can reciprocate in the directions D along the 
roller 3. The recording head 5 and four ink cartridges 7 are mounted on 
the carriage 6 removably. The head 5 includes portions each associated 
with one of the cartridges 7. The cartridges 7 are filled with yellow, 
black, cyanogen and magenta inks, respectively, and can supply the inks 
each to one of the head portions. 
As shown in detail in FIG. 2, the carriage 6 includes a portion 6a on which 
the cartridges 7 can be mounted. When the cartridges 7 are mounted on the 
carriage portion 6a, they are connected through a manifold 15 to the 
recording head 5 supported by a head support 16. A rear end portion of the 
manifold 15 extends through the front wall 6b of the carriage portion 6a, 
and is connected through a joint 17 to the cartridges 7. The cartridges 7 
each have an ink supply hole 7a, which is fitted with an adapter 18 for 
engaging with the joint 17 on its front side. The adapter 18 is fitted 
with a mesh filter 19 on its rear side for preventing foreign substances 
from moving with ink to the head 5. 
A carriage shaft 8 and a guide rail 9 extend in parallel to the platen 
roller 3, and are fixed to the frame 2. The carriage 6 is supported 
slidably on the shaft 8, and includes a protrusion or portion 6c, which is 
guided or supported slidably on the rail 9. This enables the recording 
head 5 mounted on the carriage 6 to reciprocate along the roller 3. 
A carriage drive mechanism CM includes a timing belt 11, to which the 
carriage 6 is fixed, and a pair of timing pulleys 12 and 13, between which 
the belt 11 is extended. The pulley 12 is coupled to a carriage drive 
motor (CR motor) 10, which may be a step motor or a DC motor. The rotation 
of the motor 10 drives the mechanism CM to reciprocate the carriage 6 in a 
recording area, where a printing sheet 4 can be printed. The recording 
area extends along the platen roller 3. The mechanism CM and the motor 10 
constitute an apparatus for moving the carriage 6 between the recording 
area and a recovery area, where the recording head 5 can recover by means 
of a suction cap 41, a suction pump 42 and a wiper 32. The recovery area 
is formed on the left (right in FIG. 1) of the recording area. The 
carriage 6 is fitted with switches 21, one of which is shown in FIG. 5, 
for detecting the replacement of the cartridges 7. The switches 21 are not 
shown in detail in FIG. 1. 
Formed on the right (left in FIG. 1) of the recording area is a flushing 
area, where a waste ink receiver 22 is fitted for discharging the ink in 
the recording head 5 in advance just before the printing operation of the 
head 5 to eliminate the clogging of the nozzles of the head 5 and remove 
the air bubbles mixing with the ink in the nozzles. While operating, an 
ink jet type recording head may become defective or bad in ejection of ink 
due to air bubbles produced in it, dried ink or other cause. In the 
recovery area, a purge mechanism RM is fitted for restoring the recording 
head 5 from defective ejection. The purge mechanism RM includes a suction 
apparatus 31, which includes the suction cap 41 and the pump 42. The cap 
41 can move between its protruding position where it is protruded into the 
path of movement of the recording head 5 and its standby or waiting 
position where it is retracted from the path. In its protruding position, 
the cap 41 is in close contact with the surface of the head 5 on which 
nozzles are formed(the surface will be referred hereafter as "nozzle 
formed surface"). The pump 42 sucks ink in the head 5 through the cap 41 
in close contact with the nozzle formed surface. 
On the right and left (left and right in FIG. 1) of the suction apparatus 
31, the wiper 32 and a capping device or apparatus 33 are fitted, 
respectively. The wiper 32 can move relative to the recording head 5 
perpendicularly to the axis of the platen roller 3 to wipe the nozzle 
formed surface of the head 5. While the head 5 is not operating, the 
capping device 33 caps the nozzle formed surface to prevent the ink from 
evaporating and thereby keep the surface from drying. 
The wiper 32, the suction cap 41 and the pump 42 are associated with a cam 
43. The turning of the cam 43 controls the movement of the wiper 32, the 
movement of the suction cap 41 and the operation of the pump 42. 
As shown in FIG. 3, the cam 43 includes a driven gear 46 formed integrally 
with it. The gear 46 can engage with and disengage from a drive gear (not 
shown), which can be driven by the LF motor 14 of the sheet feed mechanism 
LM. In this case, the motor 14 can turn the cam 43 in one direction. The 
cam 43 has a first cam groove 43a and a second cam groove 43b on its one 
side, and a third cam groove 43c and a fourth cam groove 43d on the other. 
The wiper 32 is held by a holder 34 having a cam follower formed on its 
rear end, which is in slidable engagement with the first cam groove 43a. 
The turning of the cam 43 reciprocates the wiper 32 perpendicularly to the 
path of movement of the recording head 5, and between its protruding 
position where it is protruded into the path and its standby position 
where it is retracted from the path. In the protruding position, the wiper 
32 can wipe the nozzle formed surface of the head 5. The suction cap 41 is 
held by a holder 44 having a cam follower formed on its rear end, which is 
in slidable engagement with the second cam groove 43b. 
The pump 42 includes a cylindrical housing 52 mounted on and fixed to a 
frame member 51, which is fixed to the printer frame 2. The pump housing 
52 has a suction port 52a and a discharge port 52b which are spaced 
axially of it. The suction port 52a is connected through a suction tube 55 
to the suction cap 41. The discharge port 52b is connected to a waste ink 
tank 58 (FIG. 1) holding an ink absorber 57. The rear end 52c of the 
housing 52 opens to the atmosphere. A first piston 53 and a second piston 
54 can independently reciprocate in the housing 52. The first piston 53 is 
adjacent to the open end 52c of the housing. 
The first piston 53 and the second piston 54 are connected to the rear ends 
of a first drive shaft 61 and a second drive shaft 62, respectively. The 
first shaft 61 extends slidably through the second piston 54 and 
telescopically into the second shaft 62. The pistons 53 and 54 define a 
pump chamber between them around the first shaft 61 in the housing 52. The 
shafts 61 and 62 include a cam follower 63 and a cam follower 64 supported 
on their respective front ends. The followers 63 and 64 are in slidable 
engagement with the cam grooves 43c and 43d, respectively. 
These cam grooves 43c and 43d are shaped for a number of sucking movements 
of the pistons 53 and 54. As stated later, the cam 43 can turn and pause. 
Various combinations of turning and pausing of the cam 43 control the 
suction force and time of the pump 42. The turning of the cam 43 at 
predetermined timing causes, in order, the suction cap 41 to cap the 
nozzle formed surface, the pump 42 to suck ink from the recording head 5, 
and the wiper 32 to wipe this part of the surface. The sucked ink is 
discharged through the pump 42 into the waste ink tank 58, where it is 
absorbed by the absorber 57. 
As shown in FIG. 1, the capping apparatus 33 includes a casing 72, which 
supports four preservation caps 71 each for capping one of the four 
portions of the recording head 5. The cap casing 72 is supported slidably 
and pivotably on a guide rod 73, which extends in parallel to the carriage 
shaft 8 and is fixed to the frame 2. The casing 72 includes a protrusion 
72a protruding forward to engage with the carriage 6. The casing 72 is 
urged or biased to the left in FIG. 1 by a spring (not shown) and 
clockwise in FIG. 1 by another spring (not shown). When the carriage 6 
moves from the recording area to the recovery area, it engages with the 
casing protrusion 72a and moves with the casing 72. Consequently, the 
preservation caps 71 follow the carriage 6 to the right in FIG. 1. When 
the casing 72 slides in this direction, an inclined cam (not shown) causes 
it to pivot around the guide rod 73 counterclockwise in FIG. 1. As a 
result, the caps 71 contact with and cap the nozzle formed surface of the 
recording head 5. When the carriage 6 moves back toward the recording 
area, the caps 71 move toward this area and, at the same time, leave the 
head 5 clockwise in FIG. 1. When the carriage 6 leaves the recovery area, 
the printer 1 returns to its initial condition. 
U.S. Pat. No. 5,639,220 discloses an ink jet printer including a purge 
mechanism, a capping apparatus and a wiper, all as stated above, and is 
incorporated herein by reference. 
With reference to FIG. 5, the controller of the printer 1 includes a CPU 
100, which is a known processing unit. The CPU 100 is connected through an 
interface 101 to a host computer 102, which may be a personal computer. 
The CPU 100 can receive printing commands from the computer 102, and carry 
out various types of printing in accordance with the commands. 
Typical operating systems of a personal computer include a window system. 
The host computer 102 operates with a window system, on which various 
applications (A, B, . . . N) run. Incorporated in the system are a font 
driver, CRT driver, a keyboard driver, a mouse driver, a printer driver, 
etc. When the printer 1 prints a sheet of paper while some of the 
applications are running, the printer driver outputs data related to an 
image suitable for the printing function of the printer. The CPU 100 is 
connected to an operating panel 103, a ROM 104 and a RAM 105. The panel 
103 is used to set and display sheet size and other parameters. The ROM 
104 is used to store programs for controlling the printer 1. The RAM 105 
is used to temporarily store the printing data transferred from the host 
computer 102 and numeric values for controlling the printer 1. The RAM 105 
has a backup memory 105a. 
The CPU 100 controls the driving of the LF motor 14, the CR motor 10 and 
the recording head 5 through an LF drive circuit 111, a CR drive circuit 
112 and a head drive circuit 113, respectively. The CPU 100 receives 
signals from the switches 21, which are fitted on the carriage 6, for 
detecting the replacement of the cartridges 7. 
A switching or change-over mechanism 121 includes the drive gear (not 
shown) which can mesh with the driven gear 46 of the cam 43. The LF motor 
14 can drive one of the purge mechanism RM and the sheet feed mechanism LM 
selectively through the switching mechanism 121. The CPU 100 can control 
the operation of the pump 42 to make a purge. 
As shown in FIG. 8A, the pump 42 can perform a series of actions or 
performances including a plurality of suction actions. By controlling the 
pump 42 through the cam 43, the CPU 100 can selectively combine some or 
all of the suction actions to change the number of suction actions and the 
suction force of the pump 42. For example, the replacement of each 
cartridge 7 involves suction actions which are small in suction force and 
each short in suction time to suck ink without the ink bubbling. The 
periodic maintenance of the recording head 6 involves a suction action 
which is relatively great in suction force and relatively long in suction 
time to maintain a good ejection condition. The recovery of the head 5 
from defective ejection involves a suction action which is great in 
suction force and long in suction time. 
In accordance with a second embodiment of the invention, the control of the 
CPU 100 can drive the pump pistons 53 and 54 selectively at different 
speeds in a suction action for sucking ink from the recording head 5 by 
means of the suction apparatus 31 with the suction cap 41 in close or 
tight contact with the nozzle formed surface of the head 5. Specifically, 
the pistons 53 and 54 can be driven selectively at different speeds by 
combinations of continuous driving and intermittent driving of the 
pistons, combinations of intermittent driving of one of the pistons at a 
cycle period (frequency) and intermittent driving of the other piston at 
another cycle period, or combinations of all of them. 
In accordance with a third embodiment of the invention, the pump 42 can 
perform a series of actions including a plurality of suction actions. The 
CPU 100 can control the pump 42 in such a manner that one or more of the 
suction actions vanish selectively. Specifically, as shown in FIG. 14A, 
the pump 42 can perform a first suction action A and a second suction 
action "b". The action "a" is small in suction force and short in suction 
time (a small wave of negative pressure). The second action "b" is great 
in suction force and long in suction time (a large wave of negative 
pressure). When each cartridge 7 is replaced and the CPU 100 receives a 
signal from the associated detection switch 21, the CPU selects both of 
the first and second suction actions, and makes neither of them vanish 
(FIG. 14A). For a normal purge without replacing the cartridges 7, the CPU 
100 controls the rotation of the LF motor 14, which drives the cam 43, in 
such a manner that the first action "a" vanishes and only the second 
action "b" is performed (FIG. 14B). 
The CR motor 10 can, as stated above, drive the carriage drive mechanism 
CM. The movement of the carriage 6 causes the switching mechanism 121 
(FIG. 5) to change over. 
The purge mechanism RM has a purge HP sensor 131. The sheet feed mechanism 
LM has a PE sensor 132. The carriage drive mechanism CM has a CR position 
sensor 133. The sensors 131, 132 and 133 can supply the CPU 100 with 
detection signals through a counter group 122, which consists of a purge 
position counter 122a, an LF position counter 122b and a CR position 
counter 122c. 
When the pump 42 is at its home position (0 degree in FIG. 7), the purge HP 
sensor 131 signals or informs the purge position counter 122a that the 
pump is at this position. This signal is the reference for the purging 
operation of the purge mechanism RM. 
When the PE sensor 132 detects the front end of a newly fed recording sheet 
4, it signals the LF position counter 122b. This signal is the reference 
for controlling the recording position in the direction of sheet movement. 
The CR position sensor 133 counts the drive pulses of the CR motor 10 to 
detect the position of the carriage 6, and informs the CR position counter 
122c of this position. This positional information is the reference for 
controlling the holding position in the directions of carriage movement. 
This information is also the reference with (by) which it is decided 
whether a new recording sheet can be fed and whether a printed sheet can 
be discharged. 
The operation of the printer 1 will be explained below. Normally, the 
recording head 5 is in its standby position, where it is capped with the 
preservation caps 71. Then, if recording data are input into the CPU 100, 
the printer 1 starts recording. A recording sheet 4 is fed to the space 
between the platen roller 3 and the recording head 5. In the meantime, the 
CR motor 10 operates to move the head 5 from the standby position to the 
recording start position. The head 5 prints the sheet 4 by ejecting ink in 
accordance with the recording data while reciprocated in the recording 
area. When the printing ends, the head 5 is returned to the standby 
position, where it is capped with the preservation caps 71 in order for 
its nozzle formed surface to be kept from drying while it is not used. 
For example, if defective ejection of ink occurs, the printer user may 
decide to turn on the purge switch on the operating panel 103. If the 
purge command is input into the CPU 100, the printer 1 is put in the purge 
mode, in which the purge mechanism RM operates and, as stated later, a 
suction program runs. 
If defective ejection of ink occurs, the purge switch may be turned on to 
cause the pump 42 to suck ink as stated above. The pump 42 sucks ink also 
when each cartridge 7 is replaced with a new one and it is therefore 
necessary to suck ink from the new cartridge into the recording head 5. If 
each cartridge 7 is replaced, the associated detection switch 21 on the 
carriage 6 detects the replacement. Then, the control of the CPU 100 
causes the pump 42 to suck ink. If the head 5 is not used for recording 
for a long time, its nozzles start to dry even though its nozzle formed 
surface is capped with the preservation caps 71. In this case, the pump 42 
sucks ink for automatic maintenance depending on the length of the nonuse 
period, to maintain a good ejection condition. When printing starts or at 
another time, the pump 42 sucks ink automatically in accordance with the 
length of the nonuse period just before then by means of a timer, which is 
formed by the CPU 100, the ROM 104 and the RAM 105. 
During automatic maintenance, the pump 42 is controlled in such a manner 
that the pistons 53 and 54 are driven at lower speeds than during a purge 
for recovery from defective ejection of ink to lower the maximum negative 
pressure for suction. After cartridge replacement, the pump 42 is 
controlled in such a manner that the pistons 53 and 54 are driven at even 
lower speeds than during automatic maintenance to further lower the 
maximum negative pressure for suction. Thus, depending on the conditions 
of the nozzles in the recording head 5 and the ink passages, the form of 
suction is varied as stated later. 
In the third embodiment described later, the introduction of ink after 
cartridge replacement involves the first suction action "a", which is 
small in suction force and short in suction time, and the second suction 
action "b", which is great in suction force and long in suction time (FIG. 
14A). On the other hand, for ink suction not after cartridge replacement, 
the CPU 100 makes the first action vanish (FIG. 14B) to vary the form of 
ink introduction. 
In the purge mode, on the basis of the suction program, the CPU 100 first 
makes the CR drive circuit 112 actuate the CR motor 10 to drive the 
carriage drive mechanism CM in such a manner that the recording head 5 
moves from the position where it faces the preservation caps 71 to the 
position where it faces the suction cap 41. When the head 5 is positioned 
in the recovery area, the LF motor 14 is already switched by the switching 
mechanism 121 to its condition in which it can transmit driving force to 
the purge mechanism RM. The driving force from the LF motor 14 turns the 
cam 43. For a good ejection condition, the wiper 32, the suction cap 14 
and the pump 42 are controlled to perform a series of recovery actions for 
the head 5. The recovery actions include bringing the cap 41 and the wiper 
32 into and out of contact with the head 5, sucking ink from the head 5 by 
means of the pump 42, and discharging the sucked ink by means of the pump. 
The suction actions of the pump 42 include sucking ink from the head 5 
with the cap 41 in close contact with the nozzle formed surface, and 
sucking ink from the inside of the cap 41 together with air with at least 
part of the cap out of contact with the nozzle formed surface. 
With reference to FIGS. 6A-6L, 7 and 8A-8D, the contact or engagement of 
the suction cap 41 and the wiper 32 with the recording head 5, the 
disengagement of them from it, and the suction and the discharge by means 
of the pump 42 in accordance with the first embodiment will be described 
below along the change in the turning angle of the cam 43. In this 
embodiment, the turning speed of the cam 43 is constant. 
With reference first to FIG. 6A, when the turning angle of the cam 43 is 
around 0 degree, the pump chamber 52e between the pistons 53 and 54 is 
smallest in volume, and positioned near the discharge port 52b. In the 
meantime, the suction cap 41 is in its initial condition, in which it is 
at its standby position away from the recording head 5 (FIG. 7). 
While the cam 43 is turning from its turning angle of about 6 degrees, the 
pistons 53 and 54 move backward together gradually at the same speed (FIG. 
6B). At about 57 degrees, the pistons 53 and 54 decelerate a little. At 
about 97 degrees, the pistons 53 and 54 are accelerated by the forms of 
the cam grooves 43c and 43d. When the cam 43 reaches its turning angle of 
about 57 degrees, as shown in FIG. 7, while the pistons 53 and 54 are 
moving, the suction cap 41 starts to move gradually from its standby 
position to the path of movement of the recording head 5. At about 86 
degrees, the cap 41 starts to cap the nozzle formed surface of the head 5. 
When the turning angle of the cam 43 reaches about 108 degrees (FIG. 6C), 
the second piston 54 stops while only the first piston 53 is moving so 
that the pump chamber 52e enlarges and communicates with the suction port 
52a (FIG. 6D). At about 114 degrees, the first piston 53 stops. From about 
114 through 129 degrees, both pistons 53 and 54 keep stopping. At about 
121 degrees (position A), the cam 43 stops for three seconds so that a 
first suction action which is small in suction force and short in suction 
time is performed ("a" in FIGS. 8A-8D). 
Then, the pistons 53 and 54 move toward the discharge port 52b until the 
first piston 53 closes the suction port 52a (FIG. 6E). After this port 52a 
is closed and until the cam 43 turns to 158 degrees, the pistons 53 and 54 
stop. From 158 through 164 degrees, while the second piston 54 is 
stopping, the first piston 53 moves away from the second piston so that 
the piston chamber 52e enlarges and communicates with the suction port 52a 
again (FIG. 6F). From 164 through 179 degrees, both pistons 53 and 54 
stop. At about 171 degrees (position B), the cam 43 stops for three 
seconds so that a second suction action which is small in suction force 
and short in suction time is performed ("b" in FIGS. 8A and 8C). 
The pistons 53 and 54 are moved differently by the different profiles of 
the cam grooves 43d and 43c engaging with the drive shafts 61 and 62, 
respectively, connected to the pistons 53 and 54, respectively. 
While the cam 43 is turning from 179 through 184 degrees and the first 
piston 53 is stopping, the second piston 54 moves away from the first 
piston (FIG. 6G) to enlarge the pump chamber 52e. From 184 through 200 
degrees, both pistons 53 and 54 stop. At about 192 degrees (position C), 
the cam 43 stops for three seconds so that a third suction action which is 
small in suction force and short in suction time is performed ("c" in FIG. 
8A). 
Normally, the cam 43 turns at a speed of 120 degrees per second (360 
degrees in 3 seconds). Without halting or temporarily stopping at the 
position B, the cam 43 may stop at the position C for five seconds. This 
is equivalent to the enlargement of the pump chamber 52e from 164 through 
184 degrees nearly at a time, although negative pressure develops 
momentarily at 164 degrees. This enlargement of the chamber 52e makes the 
negative pressure for suction higher than if the cam 43 stops at the 
position B. As a result, a suction action is performed with great suction 
force for a relatively long time ("e" in FIG. 8B). 
While the cam 43 is turning from 200 through 205 degrees and the first 
piston 53 is stopping, the second piston 54 moves away from the first 
piston (FIG. 6H) to make the pump chamber 52e larger. From 205 through 239 
degrees, both pistons 53 and 54 stop to keep the chamber 52e constant in 
volume. At about 211 degrees (position D), the cam 43 stops for three 
seconds so that a fourth suction action which is small in suction force 
and short in suction time is performed ("d" in FIG. 8A). 
Without halting at the position C, the cam 43 may stop at the position D 
for three seconds. This is equivalent to the enlargement of the pump 
chamber 52e from 184 through 205 degrees nearly at a time, although 
negative pressure develops momentarily at 184 degrees. This enlargement 
makes the negative pressure for suction higher than if the cam 43 stops at 
the position C. As a result, a suction action is performed with great 
suction force for a relatively long time ("f" in FIG. 8C). 
Otherwise, without halting at the positions B and C, the cam 43 may stop at 
the position D for five seconds. In this case, the enlargement of the pump 
chamber 52e from 164 through 205 degrees occurs nearly at a time, making 
the negative pressure for suction very high. As a result, a suction action 
is performed with great suction force for a long time ("g" in FIG. 8D). 
While the cam 43 is turning from 239 through 272 degrees and the first 
piston 53 is stopping, the second piston 54 moves farther from the first 
piston (FIG. 6I) to suck ink. From about 272 degrees, the first piston 53 
follows the second piston 54, and closes the suction port 52a. 
When the cam 43 reaches about 282 degrees, the second piston 54 makes the 
pump chamber 52e communicate with the suction port 52b (FIG. 6J), and 
stops. In the meantime, until about 338 degrees, the first piston 53 keeps 
moving, contracting the chamber 52e to perform a discharge action (FIG. 
6K). While the cam 43 is turning from about 86 through about 250 degrees, 
the suction cap 41 is kept in close contact with the nozzle formed surface 
of the recording head 5. 
From 250 through 268 degrees, the cap 41 retracts gradually from the head 
5. From 268 through 298 degrees, the cap 41 retracts further at a slightly 
lower speed. When the cam 43 turns to 298 degrees, the cap 41 returns to 
its initial position. Therefore, from about 250 degrees, the movements of 
the pistons 53 and 54 do not suck ink from the head 5, but discharges ink 
remaining in the cap 41 and the tube 55. 
After the ink is discharged, both pistons 53 and 54 stop while the cam 43 
is turning from 338 through 345 degrees. From 345 through 354 degrees, the 
pistons 53 and 54 move a little back to the position shown in FIG. 6L. 
This returns the pump 42 to its substantially initial condition. This 
condition is maintained from 354 through 360 (0) degrees, and then the 
pump 42 returns to its initial condition. 
The wiper 32 is kept in its standby condition while the cam 43 is turning 
from 0 through 287 degrees. The wiper 32 moves forward gradually from 287 
through 300 degrees, reaches its protruding position at 300 degrees, and 
keeps this position from 300 through 320 degrees. In the protruding 
position, the wiper 32 wipes the nozzle formed surface of the recording 
head 5 moving toward the recording area (FIG. 7). The wiper 32 retracts 
gradually from 320 through 333 degrees, reaches its standby position at 
333 degrees, and keeps standing by until the cam 43 reaches 360 degrees. 
After the wiper 32 wipes the nozzle formed surface of the recording head 5, 
the head first moves to the flushing area, where ink is ejected 
preliminarily from all the nozzles of the head 5 into the waste ink 
receiver 22. Then, the head 5 moves to its recording start position. 
Thus, as shown in FIG. 8A, the pump 42 can basically perform the four 
suction actions. As shown in FIGS. 8B-8D, the CPU 100 can change the 
number of suction actions and the suction force, with the four actions 
selectively combined, by skipping or omitting the halt or halts of the cam 
43 at any of the positions B, C and D. 
After each cartridge 7 is replaced with a new one, the ink passage between 
the recording head 5 and the new cartridge is filled with air. If the pump 
42 applied high negative pressure through the suction cap 41 to suck ink 
at a dash or whack from the head 5 connected to the new cartridge 7, a 
mixture of ink and air would flow rapidly from the cartridge 7 toward and 
into the head. The rapidly flowing ink would bubble, and consequently the 
ink in the head 5 would contain air bubbles. As shown in FIG. 8A, however, 
by performing the four suction actions which are small in suction force 
and each short in suction time, it is possible to suck ink gradually from 
the new cartridge 7 while expelling the air in the associated ink passage. 
Therefore, when ink is sucked from the new cartridge 7, the ink is 
prevented from bubbling, and consequently the ink in the head 5 is 
prevented from containing air. 
For example, the first suction action "a" indicated in FIG. 8A may cause 
ink to flow gradually through the cartridge filter 19. The second action 
"b" may fill the manifold 15 gradually with ink. The third action "c" may 
introduce ink into the associated channels in the recording head 5. The 
fourth action "d" may suck a predetermined amount of ink from the head 5 
into the suction cap 41. 
Before printing starts, automatic maintenance is performed depending on the 
length of the nonuse period. In this case, because the ink passage between 
each cartridge 7 and the recording head 5 is filled with ink, even great 
suction force causes no ink to bubble. In this case, it is only necessary 
to remove drying ink. As shown in FIGS. 8B and 8C, the removal of drying 
ink involves the suction action "e" or "f" which is relatively great in 
suction force and relatively long in suction time to maintain a good 
ejection condition. Either of FIGS. 8B and 8C may be selected properly 
depending on the length of the nonuse period. 
As shown in FIG. 8D, a purge for recovery from defective ejection involves 
the suction action "g" which is greater in suction force and longer in 
suction time. This action sucks ink at a dash through the suction cap 41 
to recover a good ejection condition. 
Thus, after cartridge replacement, during periodic maintenance, and during 
a purge for recovery from defective ejection, it is possible to perform 
the optimum suction actions depending on the conditions of the nozzles in 
the recording head 5 and the ink passages by varying the form of ink 
suction. Each of the suction forms shown in FIGS. 8A-8D begins with the 
first suction action "a", which is small in suction force and short in 
suction time. The first action "a" may, however, be omitted as the 
occasion demands. 
Depending on purposes, two or more series of actions including the suction 
actions may be performed. For example, after each cartridge 7 is replaced, 
the first through fourth suction actions are performed in order as the 
first series of actions to introduce ink into the recording head 5 without 
the ink bubbling as stated above. As each of the second and subsequent 
series, any of the suction forms shown in FIGS. 8B-8D is performed because 
no ink bubbles. This makes it possible to fill the head 5 securely with 
new ink so that the head can eject ink. A combination of the forms shown 
in FIGS. 8B-8D can be repeated also during a purge performed suitably by 
the user's keying, and during maintenance performed automatically by the 
printer. In particular, for automatic maintenance, the number of 
repetitions may be set depending on the length of the nonuse period. 
In accordance with this embodiment, it is decided when each cartridge 7 
should be replaced by whether there is a signal from the associated 
detection switch 21 or not. Otherwise, this might be decided by the user's 
keying. The pump 42 might include a single piston, in place of the pistons 
53 and 54. It might be possible to change the speeds of the pistons 53 and 
54 by varying the rotational speed of the motor 14, instead of driving and 
halting the pistons. The piston pump 42 might be replaced by another type 
of pump. 
Second Embodiment 
An ink jet printer according to the second embodiment is substantially 
identical with the printer 1 of the first embodiment, and equivalent parts 
are assigned the same reference numerals. The cam grooves 43c and 43d 
(FIG. 3) of this embodiment are formed differently from the counterparts 
of that embodiment. 
With reference to FIGS. 9A-9H, 10 and 11A-11E, the contact of the suction 
cap 41 and the wiper 32 with the recording head 5, the disengagement of 
them from it, and the suction and the discharge by means of the suction 
pump 42 in accordance with the second embodiment will be described below 
along the change in the turning angle of the cam 43. 
With reference first to FIG. 9A, when the turning angle of the cam 43 is 
around 0 degree, the pump chamber 52e between the pistons 53 and 54 is 
smallest in volume, and positioned near the discharge port 52b. In the 
meantime, the suction cap 41 is in its initial condition, in which it is 
at its standby position away from the recording head 5. 
While the cam 43 is turning from about 6 degrees, the pistons 53 and 54 
move together gradually backward. At about 97 degrees, the pistons 53 and 
54 accelerate a little (FIG. 9B). When the cam 43 reaches about 114 
degrees, the forms of the cam grooves 43c and 43d stop the pistons 53 and 
54, and position the pump chamber 52e near the suction port 52a (FIG. 9C). 
In the meantime, when the cam 43 reaches about 57 degrees, as shown in FIG. 
10, while the pistons 53 and 54 are moving backward, the suction cap 41 
starts to move gradually forward from its standby position to the path of 
movement of the recording head 5. At about 86 degrees, the cap 41 starts 
to cap the nozzle formed surface of the head 5. 
After the suction cap 41 caps the head nozzle formed surface completely, 
the pistons 53 and 54 are kept in their positions of FIG. 9C while the cam 
43 is turning from 114 through 130 degrees. From 130 through 205 degrees, 
while the first piston 53 is stopping, the second piston 54 moves back 
away from the first piston (FIG. 9D). This enlarges the pump chamber 52e 
to suck ink. 
During this suction action, the suction force is controlled by the piston 
54 being driven continuously and intermittently, or intermittently at 
different cycle periods (frequencies). Specifically, the piston 54 may 
move intermittently by a constant stroke at a constant cycle period to 
control the pump chamber 52e so that the chamber volume is finally a 
target value. The piston 54 moves at a lower speed during automatic 
maintenance than during a purge for recovery from defective ejection of 
ink. The piston 54 moves even more slowly after cartridge replacement than 
during automatic maintenance. 
As stated above, the pistons 53 and 54 are associated with the cam 43, 
which is included in the purge mechanism RM. This mechanism RM can be 
driven through the switching mechanism 121 by the LF motor 14, which is 
associated with the CPU 100 as a controller. When the cam 43 turns and 
halts, the piston 54 moves and halts. The CPU 100 includes another timer 
(not shown), which can vary the halt(ing) time to change the form of ink 
suction, depending on the conditions of the nozzles in the recording head 
5 and the ink passages. More specifically, while the cam 43 is turning 
from 130 through 205 degrees, with the pump chamber 52e communicating with 
the suction port 52a, the piston 54 may be driven selectively at different 
speeds to suck ink. This can vary the maximum negative pressure for 
suction, with the amount of ink suction maintained, to change the form of 
ink suction depending on the conditions of the nozzles in the head 5 and 
the ink passages. 
For example, during a normal purge, as shown in FIG. 11A, the second piston 
54 moves, without the cam 43 halting, to enlarge the pump chamber 52e. 
This heightens the maximum negative pressure for suction to suck ink with 
great suction force at a dash. During automatic maintenance, as shown in 
FIGS. 11B-11D, the cam 43 turns intermittently by 10 degrees at a time at 
intervals of 50, 100 or 200 milliseconds. This makes the maximum negative 
pressure a little lower than during a purge so as to suck ink with 
slightly smaller suction force. The suction actions shown in FIGS. 11B-11D 
can be performed selectively depending on the length of the nonuse of the 
printer. After each cartridge 7 is replaced, as shown in FIG. 11E, the cam 
43 turns intermittently by 10 degrees at a time at intervals of 300 
milliseconds. This sucks ink gradually with even smaller suction force, 
without making the maximum negative pressure very high. 
During automatic maintenance or after cartridge replacement, ink is sucked 
with the maximum negative pressure for suction lower than during a normal 
purge, for the following reason. After each cartridge 7 is replaced with a 
new one, the ink passage between the new cartridge and the recording head 
5 is probably filled with air. In such a case, if the pump 42 applied 
great suction force through the suction cap 41 to suck ink from the new 
cartridge at a dash, as is the case with a normal purge, a mixture of ink 
and air might flow rapidly into the head 5. The rapidly flowing ink might 
bubble, and consequently the ink in the head 5 might contain air bubbles. 
This tendency is made remarkable by the filter 19 fitted between the head 
5 and the cartridge 7 to keep foreign substances from moving together with 
ink toward the head. Therefore, by sucking ink gradually with small 
suction force as shown in FIG. 11E, it is possible to cause the sucked ink 
to flow slowly through the filter 19 and the ink passage. This can 
restrain the ink from bubbling, and consequently fill the recording head 5 
with ink containing no air. 
During automatic maintenance, the ink passage between each cartridge 7 and 
the recording head 5 is filled with ink. Therefore, no ink bubbles even 
with somewhat great suction force. In this case, however, because ink is 
drying, even slightly small suction force as mentioned above is sufficient 
to remove the ink concentrated a little. While the cam 43 is turning from 
205 through 239 degrees, the pistons 53 and 54 stop. From 239 through 272 
degrees, while the first piston 53 is stopping and the pump chamber 52e is 
communicating with the suction port 52a, the second piston 54 moves away 
from the first piston to the position shown in FIG. 9E, where the rear end 
of the second piston 54 closes the discharge port 52b. This sucks ink 
while making the chamber 52e larger. In the meantime, at 250 degrees, the 
suction cap 41 starts to leave the recording head 5 and be exposed to the 
atmosphere. This suction action sucks the ink remaining in the cap 41 and 
the suction pipe 55. 
While the cam 43 is turning from 272 through 282 degrees, the first piston 
53 moves forward and closes the suction port 52a (FIG. 9F). At the same 
time, the second piston 54 keeps moving forward. At about 282 degrees, as 
shown in FIG. 9F, the second piston 54 stops in its position where it 
makes the pump chamber 52e communicate with the discharge port 52b. Until 
about 338 degrees, the first piston 53 keeps moving forward (FIG. 9G), 
contracting the chamber 52e to discharge ink positively out of it into the 
waste ink tank 58. 
While the cam 43 is turning from 338 through 345 degrees after the ink is 
discharged, both pistons 53 and 54 stop. From 345 through 354 degrees, the 
pistons 53 and 54 move together slightly backward to their positions shown 
in FIG. 9H, where they are in their substantially initial condition. This 
condition is maintained from 354 through 360 (0) degrees, and then the 
pump 52 returns to its initial condition. 
In the meantime, while the cam 43 is turning from 0 through 287 degrees, 
the wiper 32 stands by. From 287 degrees, the wiper 32 moves forward 
gradually until it reaches its protruding position at 300 degrees. From 
300 through 320 degrees, the wiper 32 keeps protruding in this position, 
where it wipes the nozzle formed surface of the recording head 5 moving 
toward the recording area (FIG. 10). From 320 through 333 degrees, the 
wiper 32 moves back gradually. From 333 through 360 degrees, the wiper 32 
is kept in its standby position. In accordance with this embodiment, a 
single recovery process involves only one turn of the cam 43. Otherwise, a 
single recovery process may involve two or more turns of the cam 43. In 
other words, for securer recovery, the cam 43 may turn continuously by two 
or more turns to repeat the suction action. After each cartridge 7 is 
replaced, the suction action of FIG. 11E may be repeated. For the second 
time and later, however, because the associated ink passage is filled with 
ink, the suction action may be repeated with greater suction force. This 
can securely fill the recording head 5 with ink. The pump 52 sucks ink by 
the second piston 54 moving intermittently by a constant stroke at a time 
at a predetermined cycle period (frequency). Otherwise, one or both of the 
pistons 53 and 54 may move in this manner, or continuously at low speed. 
It is essential for the suction apparatus of this embodiment to include at 
least one piston which can move in the cylinder body, and which can be 
driven by the controller selectively at different speeds during a suction 
action with the apparatus sucking ink from the recording head while the 
suction cap is in close contact with the head nozzle formed surface. 
Third Embodiment 
An ink jet printer according to the third embodiment is substantially 
identical with the printers of the first and second embodiments, and 
equivalent parts are assigned the same reference numerals. The cam grooves 
43c and 43d (FIG. 3) of this embodiment are formed differently from the 
counterparts of those embodiments. 
With reference to FIGS. 12A-12J, 13, 14A and 14B, the contact of the 
suction cap 41 and the wiper 32 with the recording head 5, the 
disengagement of them from it, and the suction and the discharge by means 
of the suction pump 42 in accordance with the third embodiment will be 
described below along the change in the turning angle of the cam 43. 
With reference first to FIG. 12A, when the turning angle of the cam 43 is 
around 0 degree, the pump chamber 52e between the pistons 53 and 54 is 
smallest in volume, and positioned near the discharge port 52b. In the 
meantime, the suction cap 41 is in its initial condition, in which it is 
at its standby position. 
While the cam 43 is turning from about 6 degrees, the pistons 53 and 54 
move gradually backward together. At about 97 degrees (FIG. 12B), the 
pistons 53 and 54 accelerate a little. At about 114 degrees, the pistons 
53 and 54 stop, and the pump chamber 52e is positioned near the suction 
port 52a (FIG. 12C). 
In the meantime, when the cam 43 reaches about 57 degrees while the pistons 
53 and 54 are moving, as shown in FIG. 13, the suction cap 41 starts to 
move forward from its standby position gradually toward the path of 
movement of the recording head 5. At about 97 degrees, the cap 41 starts 
to cap the nozzle formed surface of the head 5. 
While the cam 43 is turning from 114 through 122 degrees after the suction 
cap 41 caps the head nozzle formed surface completely, the pistons 53 and 
54 keep stopping at their positions of FIG. 12C. From 122 through 129 
degrees, while the first piston 53 is stopping, the second piston 54 moves 
away from the first piston (FIG. 12D). This enlarges the pump chamber 52e 
and makes it communicate with the suction port 52a to start the first 
suction action. From 129 through 145 degrees, both pistons 53 and 54 stop. 
If each cartridge 7 is replaced, the associated detection switch 21 sends a 
signal to the CPU 100. In response to the signal, when the cam 43 reaches 
about 136 degrees (position 3A in FIG. 13), the CPU 100 interrupts the 
energization of the LF motor 14 for about three seconds to stop the cam 
43. As a result, the first suction action ("a" in FIG. 14A) is performed 
for about three seconds. The amount of ink sucked by this first action may 
be such that ink can flow from the cartridge 7 through the associated 
filter 19 into the manifold 15. 
On the other hand, for ink suction not after cartridge replacement, the cam 
43 does not stop at the position 3A, but turns from 122 through 145 
degrees in about 0.225 second. This makes the first piston 53 close the 
suction port 52a immediately (FIG. 12E). Consequently, as shown in FIG. 
14B, the first suction action "a" appears for an instant, but no 
substantial suction action is performed. Substantially, the first action 
"a" vanishes. 
While the cam 43 is turning from 145 through 171 degrees, with the volume 
of the pump chamber 52e maintained, as shown in FIG. 12E, the pistons 53 
and 54 move forward, and the first piston 53 closes the suction port 52a. 
In the meantime, the second piston 54 closes the discharge port 52b. 
While the cam 43 is turning from 171 through 179 degrees, the pistons 53 
and 54 stop. From 179 through 205 degrees, with the second piston 54 
stopping and closing the discharge port 52b, as shown in FIG. 12F, the 
first piston 53 moves away from the second piston. This enlarges the 
chamber 52e to heighten the negative pressure in it. At 205 degrees, the 
first piston 53 stops with the chamber 52e communicating with the suction 
port 52a. From 205 through about 239 degrees, with this communication 
maintained, both pistons 53 and 54 stop. 
When the cam 43 reaches about 211 degrees (position 3B in FIG. 13), it 
stops for five seconds. This performs the second suction action "b" (FIGS. 
14A and 14B), which is greater in suction force and longer in suction time 
than the first action "a". The amount of ink sucked by the second action 
"b" is larger than the amount of new ink for filling the associated 
channels in the recording head 5, and is sufficient to restore the head 5 
to its good condition of ejection. 
When the cam 43 reaches 221 degrees, the suction cap 41 starts to leave the 
recording head 5. In the meantime, from 239 through 272 degrees, with the 
first piston 53 stopping and the pump chamber 52e communicating with the 
suction port 52a, the second piston 54 moves away from the first piston to 
the position of FIG. 12G, where its rear end closes the discharge port 
52b. This performs a suction action while making the chamber 52e larger. 
This action sucks, together with air, the ink remaining in the suction cap 
41 and the suction pipe 55. 
While the cam 43 is turning from 272 through 282 degrees, as shown in FIG. 
12H, the second piston 54 keeps moving forward. At the same time, the 
first piston 53 moves forward and closes the suction port 52a. The second 
piston 54 moves until the pump chamber 52e communicates with the discharge 
port 52b. At about 282 degrees, the second piston 54 stops. In the 
meantime, until about 338 degrees, the first piston 53 keeps moving, 
contracting the chamber 52e to perform a positive discharge action (FIG. 
12I). This discharges ink from the chamber 52e into the waste ink tank 58. 
While the cam 43 is turning from 338 through 345 degrees after the ink is 
discharged, both pistons 53 and 54 stop. From 345 through 354 degrees, the 
pistons 53 and 54 move a little back to their positions shown in FIG. 12J, 
where the pump 42 is in its substantially initial condition. This 
condition is maintained from 354 through 360 (0) degrees. Then, the pump 
42 returns to its initial condition. 
While the cam 43 is turning from 0 through 269 degrees, the wiper 32 stands 
by. From 269 through 290 degrees, the wiper 32 protrudes gradually. At 290 
degrees, the wiper 32 reaches its protruding position. From 290 through 
310 degrees, the wiper 32 keeps protruding at this position, where it 
wipes the nozzle formed surface of the recording head 5 moving toward the 
recording area (FIG. 13). From 310 through 331 degrees, the wiper 32 
retracts gradually toward its standby position. From 331 through 360 
degrees, the wiper 32 stands by at this position. 
After the wiper 32 wipes the nozzle formed surface of the recording head 5, 
the head moves to the flushing area, where ink is ejected preliminarily 
from all the nozzles of the head 5 into the waste ink receiver 22. Then, 
the head 5 moves to its recording start position. 
The control of the pump 42 by means of the cam 43 involves the two 
different suction actions differing in suction force for sucking ink from 
the recording head 5. One of the actions is the first suction action which 
is smaller in suction force. The other action is the second suction action 
which is greater in suction force and longer in suction time. The two 
actions are performed for the following reason. 
In some cases, the recording head 5 contains no ink, and the ink passage 
between the head 5 and each cartridge 7 is filled with air. In such cases, 
if the pump 42 applied high negative pressure through the suction cap 41 
to suck ink from the head 5 at a dash, a mixture of ink and air would flow 
rapidly from the cartridge 7 into the head 5. The rapidly flowing ink 
would bubble, and consequently the ink in the ejection channels of the 
head 5 would contain air bubbles. 
The first suction action causes ink to flow into the passage while 
expelling the air in it. The subsequent second action fills ink into the 
recording head 5. This maintains a good condition of ejection without ink 
bubbling. The tendency to bubble is made remarkable by the filter 19 
fitted between the head 5 and the cartridge 7 to keep foreign substances 
etc. from moving together with ink toward the head as stated above. 
Therefore, the two actions are effective in particular for this 
embodiment. 
Depending on purposes, two or more series of actions including the first 
and second suction actions may be performed. For example, after each 
cartridge 7 is replaced, six series of such actions are performed 
continuously for the associated portion of the recording head 5. The first 
series includes the first and second actions to introduce ink into the 
head 5 without the ink bubbling as stated above. From the second through 
sixth series, the first action is caused to vanish, and only the second 
action is repeated, because no ink bubbles. This securely fills the head 5 
with new ink to make the head ready for ejection. 
The actions for ejection recovery or restoration may be performed either 
properly by the user's keying as stated above, or automatically by the 
printer being based on a timing action. For the automatic actions, it is 
possible to decide the number of repetitions of only the second suction 
action (with the first action caused to vanish), depending on the length 
of the measured time. In this case, by making the first action vanish, it 
is possible to save the ink and time which would otherwise be consumed by 
this action. 
Although the invention has been described in specific embodiments 1-3, the 
invention may be embodied in other specific forms without departing from 
the sprit or essential characteristics thereof. The suction pump of this 
embodiment is a piston pump, but might be replaced by a tube type pump 
which comprises a roller and a tube connected between the suction cap and 
the roller. The pump can develop negative pressure with the restoring 
force of its tube squashed by a roller.