Information
-
Patent Grant
-
6168257
-
Patent Number
6,168,257
-
Date Filed
Friday, December 12, 199726 years ago
-
Date Issued
Tuesday, January 2, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Barlow; John
- Stewart; Charles
Agents
- Daspit; Jacqueline M.
- Aust; Ronald K.
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
An ink jet printer has a maintenance station in which a movable sled starts from a known position due to a diagonally disposed return spring. A cam profile near the uppermost portion of vertical movement of a movable sled is produced in accordance with a quadratic equation. This quadratic designed equation profile reduces the force required to move the movable sled up the cam profile to its uppermost position. The return spring, which holds the movable sled in the known position by urging a front wall of the movable sled against a front wall of a support housing, also absorbs energy to decrease the noise level of the printer.
Description
FIELD OF THE INVENTION
This invention relates to an improved maintenance or service station for an ink cartridge of a printer and, more particularly, to an improved maintenance or service station for an ink cartridge of a printer having a portion of its cam surfaces formed with an unique profile and an unique spring arrangement.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,440,331 to Grange discloses a service or maintenance station for an ink cartridge of an ink jet printer. Wiping of the print head of an ink cartridge by wipers on a movable sled occurs at a first elevation to which the movable sled is raised from its lowermost position and capping of the print heads of the ink cartridges occurs at a second and higher elevation of the movable sled. The movable sled is supported in a fixed base having cam surfaces for cooperating with cam followers on the sled to raise and lower the sled.
The cam profiles of the cams are straight line surfaces. These create a need for a relatively large motor, which is driving the carrier, because of the varying forces applied by motion of the sled, which is driven by the carrier, along the cam profiles to its uppermost position.
While the aforesaid Grange patent returns the sled to its lowermost position solely by engagement of the carrier with the sled so as to require a relatively large amount of power, it has been previously suggested to return the sled to its lowermost position through the use of a return spring. This return spring applies a force solely in the direction of longitudinal movement of the movable sled. The return spring reduces the power utilized in comparison with the maintenance or service station of the aforesaid Grange patent. However, the return spring creates substantial noise in the printer when it biases the movable sled to its lowermost position because of engagement of the movable sled with its base.
SUMMARY OF THE INVENTION
The maintenance or service station of the present invention satisfactorily solves the foregoing problems. The maintenance or service station has the cam profile designed in accordance with a quadratic equation for the final portion of upward motion of the movable sled along each of the cams. This design of the cam profile reduces the required force to move the movable sled to its uppermost position, which is the position at which there is capping of the print heads on the ink cartridges, to a minimum and a constant. The required force during capping is greater than the force required to move the movable sled upwardly from its lowermost position. Therefore, the design of the final portion of the cam profile in accordance with a quadratic equation lowers power usage and enables a smaller motor to be employed for driving the carrier.
The noise level created by using the previously suggested return spring is decreased in the maintenance station of the present invention. This is accomplished by disposing the return spring so that its force is exerted at an angle to the longitudinal movement of the movable sled.
This diagonal positioning of the return spring produces a first component of the force along the longitudinal movement of the movable sled and a second component of the force perpendicular to the longitudinal movement of the movable sled. The second component of the force urges the front wall of the movable sled into engagement with the front wall of the support housing to create friction therebetween when the movable sled is returned to its lowermost position by the first component of the force of the return spring. This friction along with damping created by a viscous media on the front wall of the support housing absorbs the energy of the return spring. As a result, the left end of the movable sled does not engage the left end of the support housing with as large a force so that the noise level of the printer is reduced.
The second component of the force enables the return spring to also hold the movable sled at a known home position with respect to the support housing. That is, the return spring holds the front wall of the movable sled against the front wall of the support housing to provide the known home position. This enables more precise motion of the movable sled since it is always starting from the same fixed known home position rather than an approximate home position.
An object of this invention is to provide an improved maintenance station for use in maintaining or servicing an ink cartridge of an ink jet printer.
Another object of this invention is to provide a maintenance station having an uppermost portion of a cam profile designed in accordance with a quadratic equation to require a relatively constant minimum force for causing upward movement of a movable sled as it is moved longitudinally.
A further object of this invention is to provide a maintenance station having a return spring, which returns a movable sled to its home position, to produce a force to move the movable sled transversely to a fixed known home position and to have its energy absorbed to reduce the noise level of the printer.
Other objects of this invention will be readily perceived from the following description, claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of an ink jet printer having a maintenance station of the present invention;
FIG. 2
is an exploded perspective view of the ink jet printer of
FIG. 1
with the maintenance station separated from a carrier and taken from the rear of
FIG. 1
;
FIG. 3
is a rear sectional view, partly in elevation, of a support housing of the maintenance station having a movable sled supported therein with the movable sled retained in its intermediate or wiping position by a pivotally mounted latch;
FIG. 4
is a bottom plan view of the movable sled and its support housing with the movable sled in its intermediate or wiping position;
FIG. 5
is a fragmentary perspective view of portions of the carrier, the support housing, and the movable sled just prior to the carrier engaging the movable sled to advance the movable sled from its lowermost position in the support housing;
FIG. 6
is a fragmentary sectional view of a pivot mount for pivotally mounting the latch on the movable sled;
FIG. 7
is a sectional view, partly in elevation, similar to
FIG. 3
but with the movable sled in its lowermost or home position;
FIG. 8
is a sectional view, partly in elevation, similar to
FIG. 3
but with the movable sled in its uppermost or capping position;
FIG. 9
is a fragmentary perspective view of portions of the support housing, the movable sled, and the carrier taken from the left side in which the left portion of the movable sled is moved relative to the support housing to provide clearance of the left portion of the front wall of the movable sled from the left portion of the front wall of the support housing;
FIG. 10
is a fragmentary perspective view of portions of the movable sled, the support housing, and the carrier and showing the movable sled inadvertently disposed in its intermediate or wiping position in the support housing with the carrier having a surface to enable return of the movable sled to its lowermost position in the support housing;
FIG. 11
is a schematic diagram of the portion of the cam profile formed by the quadratic equation to produce the minimum force necessary for movement of the movable sled to its uppermost position in the support housing;
FIG. 12
is a graph of the force created by the cam profile formed by the quadratic equation of the present invention in comparison with the force created by a straight line cam profile; and
FIG. 13
is a schematic diagram showing shapes of cycloidal, quadratic, and trapezoidal cam profiles.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
Referring to the drawings and particularly
FIG. 1
, there is shown an ink jet printer
10
having a pair of removable ink cartridges
11
and
12
supported by a carrier
14
. While two of the cartridges
11
and
12
have been shown, it should be understood that only one of the cartridges
11
and
12
may be employed or more than two of the cartridges
11
and
12
may be utilized. This would depend upon whether the ink jet printer
10
is capable of printing colors and black or just black.
The carrier
14
is driven longitudinally in opposite directions along a fixed shaft
15
. The shaft
15
is supported in a fixed frame
16
as shown at end
17
of the shaft
15
.
The carrier
14
is driven from a suitable power source in opposite directions. The power source is preferably a motor (not shown), a pulley (not shown) on a shaft of the motor, and a drive belt mechanism (not shown) connecting the pulley with the carrier
14
to cause the carrier
14
to slide along the shaft
15
in either longitudinal direction in response to rotation of the motor.
The ink cartridges
11
and
12
have print heads with nozzles to supply ink to print on a sheet
18
of paper media, for example, in the well-known manner. The sheet
18
may be any paper media.
The ink jet printer
10
includes a maintenance or service station
20
for cleaning the nozzles of the print head of each of the ink cartridges
11
and
12
, ejecting ink from the nozzles, and capping the print heads when a printing cycle has been completed. Other services may also be performed if desired.
The maintenance station
20
includes a fixed support housing or base
21
, which is fixed to the frame
16
. A movable sled
22
is removably supported within a rectangular-shaped cavity
23
in the support housing
21
for both longitudinal and vertical movement therein.
A front wall
24
of the support housing
21
has a pair of cam slots
25
and
26
therein at opposite ends thereof. Similarly, a back wall
27
(see
FIG. 2
) of the support housing
21
has a cam slot
28
and a cam surface
29
therein at opposite ends thereof. Thus, there is only the single cam slot
28
in the back wall
27
of the support housing
21
.
A front wall
30
of the movable sled
22
has pins
31
(see
FIG. 1
) and
32
extending therefrom. The pin
31
is disposed in the cam slot
25
, and the pin
32
is disposed in the cam slot
26
.
Similarly, a back wall
33
(see
FIG. 2
) of the movable sled
22
has pins
34
and
35
extending therefrom. The pin
34
is disposed in the cam slot
28
, and the pin
35
rides along the cam surface
29
.
Accordingly, each of the pins
31
(see FIG.
1
),
32
,
34
(see FIG.
2
), and
35
functions as a cam follower. The cam slot
25
(see FIG.
1
), the cam slot
26
, the cam slot
28
(see FIG.
2
), and the cam surface
29
control vertical motion of the movable sled
22
during its longitudinal movement in both directions.
Each of the cam slot
25
(see FIG.
1
), the cam slot
26
, the cam slot
28
(see FIG.
2
), and the cam surface
29
has a cam profile
38
(see
FIG. 11
) based on a cam profile
39
. The cam profile
39
passes through the center of each of the pins
31
(see FIG.
1
),
32
,
34
(see FIG.
2
), and
35
.
As shown in
FIG. 11
, the cam profile
39
includes a low dwell
39
A connected by a cycloidal transition
39
B to a first or lower trapezoidal portion
39
C, which is connected by a cycloidal transition
39
D to an intermediate dwell
39
E. A cycloidal transition
39
F connects the intermediate dwell
39
E to a second or upper trapezoidal portion
39
G, which is connected by a cycloidal transition
39
H to a quadratic portion
39
I. The quadratic portion
39
I is connected by a cycloidal transition
39
J to an upper dwell
39
K.
The cam profile
38
of each of the cam slot
25
(see FIG.
1
), the cam slot
26
, the cam slot
28
(see FIG.
2
), and the cam surface
29
corresponds to the cam profile
39
(see FIG.
11
), but it is shifted slightly from the cam profile
39
. While the cam profile
38
has the cycloidal transitions of the cam profile
39
, they will not be described or identified.
Thus, the cam profile
38
includes a low dwell
40
, which is a substantially flat surface, on which each of the pins
31
(see FIG.
1
),
32
,
34
(see FIG.
2
), and
35
rests when the sled
22
(see
FIG. 1
) is in its lowermost position of FIG.
1
. The cam profile
38
(see
FIG. 11
) has a first or lower trapezoidal portion
41
, which is a straight line, extending from the low dwell
40
to a second or intermediate dwell
42
, which is a substantially flat surface.
The cam profile
38
has a second trapezoidal portion
43
extending from the intermediate dwell
42
towards an upper dwell
44
. However, the second trapezoidal portion
43
of the cam profile
38
terminates prior to the upper dwell
44
, which is a substantially flat surface. The cam profile
38
from a point
45
to the upper dwell
44
has a portion
46
formed in accordance with a quadratic equation to decrease the force required to move the sled
22
(see
FIG. 1
) upwardly therealong to a substantially constant minimum.
When the movable sled
22
is moved to the right by the carrier
14
engaging the movable sled
22
, the pins
31
,
32
,
34
(see FIG.
2
), and
35
ride up the cam profile
38
(see
FIG. 11
) to the upper dwell
44
. When the point
45
of the cam profile
38
is reached, compression caps
50
(see
FIG. 1
) and
51
have begun to compress springs
52
and
53
, respectively, because of engagement of the caps
50
and
51
with the print heads (not shown) of the ink cartridges
11
and
12
, respectively.
As the springs
52
and
53
are compressed, the force required to continue to move the caps
50
and
51
upwardly into a sealing relation with the print heads (not shown) of the ink cartridges
11
and
12
, respectively, increases. Each of the caps
50
and
51
has a sealing lip at its upper end in engagement with the print head (not shown) of each of the ink cartridges
11
and
12
, respectively.
The magnitude of the force to move the compression caps
50
and
51
to their uppermost positions in which they rest on the upper dwell
44
(see
FIG. 11
) of the cam profile
38
is determined by the cam profile
38
from the point
45
to the upper dwell
44
. It is desired that this force be maintained at a minimum since this force determines the maximum amount of power required by the motor (not shown) driving the carrier
14
(see FIG.
1
).
The force F for imparting movement of the movable sled
22
to the right is dependent upon a cam pressure angle A and the vertical forces created by movement of the caps
50
and
51
to their sealing relation with the print head (not shown) of each of the ink cartridges
11
and
12
, respectively. This relationship is defined by equation (1):
tangent A=F/F
c
=dy/dx
(1).
It should be understood that the cam pressure angle A may not be constant so that the force F varies.
The cap force F
c
is defined by equation (2):
F
c
=F
i
+ky
(2)
where k is a constant, which is the spring rate of both of the springs
52
and
53
, and y is the deflection of each of the springs
52
and
53
.
To have the force F at a minimum for moving the movable sled
22
from its lowermost position to its uppermost position, the force F is set to a constant, and equations (1) and (2) combined and integrated to determine a profile of the cam profile portion
39
I (see
FIG. 11
) having the variable cam pressure angle A. This results in the following quadratic profile for the cam profile portion
39
I as defined by the quadratic equation:
x
=(F
i
/F)
y
+(F
k/
2)
y
2
(3).
In equation (3), x represents a specific position in the x direction for a specific y position in the y direction or vice versa. This is how the quadratic profile for the cam profile portion
39
I of the cam profile
39
is designed. Using this, the cam profile portion
46
from the point
45
of the cam profile
38
to the upper dwell
44
is produced.
In the graph of
FIG. 12
, the substantially constant force of a solid curve from point A to point B is the operating force of the movable sled
22
(see
FIG. 1
) produced by the quadratic profile portion
46
(see
FIG. 11
) of the cam profile
38
. In
FIG. 12
, the
0
position corresponds to the point
45
(
FIG. 11
) of the cam profile
38
. The portion of the solid curve in
FIG. 12
between the point
0
and the point A defines a cycloidal transition to the quadratic profile portion
46
(see
FIG. 11
) from the trapezoidal profile portion
43
. The portion of the solid curve of
FIG. 12
between the point B and position
5
is the cycloidal transition to the upper dwell
44
(see
FIG. 11
) at the position
5
in FIG.
12
. The dash line curve shows the varying force created if the quadratic profile portion
46
were a trapezoid rather than a quadratic.
The operating force for moving a movable sled of a maintenance or service station along a straight line profile is in the range of 400 grams force. The design of the uppermost portion of the cam profile
38
(see
FIG. 11
) by the quadratic equation lowers this force to 300 grams force. Accordingly, this is a reduction in force of at least 25%. This is a significant reduction in the required maximum power needed by the motor, which drives the carrier
14
(see FIG.
1
), to move the movable sled
22
to its uppermost position.
When printing is completed by the ink jet printer
10
, the carrier
14
is automatically moved by a controller (not shown) of the ink jet printer
10
. The controller is a device which can be programmed to move the carrier
14
through a predetermined maintenance routine after printing is completed.
Accordingly, when the ink jet printer
10
is in a mode of operation in which a predetermined maintenance routine is to be employed, the movable sled
22
is moved in a programmed vertical and longitudinal movement. Therefore, the single drive motor for the carrier
14
may be used to direct operations of the ink jet printer
10
in its normal print of operation and in any maintenance mode of operation.
When the carrier
14
completes a printing cycle on the sheet
18
of paper media, the carrier
14
is moved to the right by the carrier controller of the ink jet printer
10
. During movement of the carrier
14
to the right in
FIG. 1
, an upstanding post
55
(see FIG.
5
), which is mounted on a rightmost wall
56
of the sled
22
, is engaged by the carrier
14
to begin movement of the movable sled
22
to the right.
The post
55
enters a slot
57
, which is defined by a straight surface
58
and an angled surface
59
on the carrier
14
. The post
55
has a straight surface
60
and an angled surface
61
, which is at the same angle as the angled surface
59
. Therefore, the post
55
is guided into the slot
57
so that its left vertical surface
62
engages a vertical surface
63
at the end of the slot
57
.
The movable sled
22
is continuously urged towards the left in
FIG. 1
by a spring
65
(see FIG.
3
). One end of the spring
65
is attached to a hook
66
extending downwardly from a bottom surface
67
(see
FIG. 4
) of the front wall
24
of the support housing
21
. The other end of the spring
65
is connected to a hook
68
at the lower end of a leg
69
(see
FIG. 3
) of a pivotally mounted latch
70
.
The latch
70
(see
FIG. 6
) is pivotally mounted to the movable sled
22
. A pivot post
71
extends from the latch
70
into a hole
71
′ in a rear wall
72
of the movable sled
22
.
As shown in
FIG. 4
, the spring
65
is disposed at an angle to the direction of longitudinal movement of the movable sled
22
. Accordingly, one component of the force exerted by the spring
65
continuously urges the movable sled
22
longitudinally to its lowermost position. The other component of the force of the spring
65
continuously urges the front wall
30
of the sled
22
against the front wall
24
of the support housing
21
.
The carrier
14
(see
FIG. 1
) starts to move the movable sled
22
to the right through engagement of the vertical surface
63
(see
FIG. 5
) on the carrier
14
with the vertical surface
62
of the post
55
on the movable sled
22
. Just prior to this engagement occurring, the angled surface
61
on the post
55
rides along the angled surface
59
of the carrier
14
to move the vertical surface
60
into engagement with the vertical surface
58
to move the right (left in
FIG. 4
because this view is taken from the rear of the printer
10
so that movements are in the opposite direction to
FIG. 1
) portion of the front wall
30
(see
FIG. 4
) of the movable sled
22
away from the inner surface
74
of the front wall
24
of the housing
21
. This results in the force of the spring
65
being picked up by movable sled
22
.
This prevents the biasing force of the spring
65
from urging the left (right in
FIG. 1
) portion of the front wall
30
of the movable sled
22
against an inner surface
74
of the front wall
24
of the support housing
21
. Thus, there is a very small drag on the movable sled
22
because of the right (left in
FIG. 1
) portion of the movable sled
22
still engaging with the inner surface
74
of the front wall
24
of the support housing
21
. It should be understood that the movable sled
22
began from a known fixed home position rather than an unknown home position as would occur if there were a clearance between the front wall
30
of the movable sled
22
and the inner surface
74
of the front wall
24
of the support housing
21
.
As the movable sled
22
(see
FIG. 1
) is moved to the right by the carrier
14
, the pins
31
,
32
,
34
(see FIG.
2
), and
35
begin to move up from the low dwell
40
(see
FIG. 11
) of the cam profile
38
to the upper dwell
44
.
As the movable sled
22
(see
FIG. 1
) is moved from its lowermost position by longitudinal movement of the carrier
14
to the right, the latch
70
(see
FIG. 7
) is advanced to the left (This is because this view is taken from the rear of the carrier
14
so that movements are in the opposite direction to
FIG. 1
) so that an angled surface
75
on a pawl
76
at the end of an arm
77
of the latch
70
engages an angled surface
78
of an arm
79
on the support housing
21
. Thus, the latch
70
moves over the angled surface
78
of the arm
79
to the position of FIG.
8
. This is when the movable sled
22
is in its uppermost position as shown by the pin
34
on the back wall
27
of the movable sled
22
resting on the upper dwell
44
.
Just after the movable sled
22
is moved upwardly past the intermediate dwell
42
(see FIG.
11
), an angled surface
79
A (see
FIG. 9
) on a post
79
B, which is fixed to the movable sled
22
and is adjacent the latch
70
, is raised sufficiently to engage a vertical surface
79
C on the carrier
14
. This moves the right (as viewed in
FIG. 4
) or left (as viewed in
FIG. 1
) portion of the movable sled
22
away from the inner surface
74
(see
FIG. 4
) of the front wall
24
of the support housing
21
to provide a clearance between the entire front wall
30
of the movable sled
22
and the inner surface
74
of the front wall
24
of the support housing
21
as shown in FIG.
4
.
The latch
70
(see
FIG. 7
) is biased against a stop pin
80
extending from the rear wall
72
(see
FIG. 6
) of the movable sled
22
by the spring
65
(see FIG.
7
). When the angled surface
75
of the pawl
76
of the latch
70
moves against the angled surface
78
of the arm
79
, it was retained there against by the force of the spring
65
because of the stop pin
80
engaging the latch
70
until the movable sled
22
moved upwardly towards its uppermost position of FIG.
8
.
Accordingly, when the movable sled
22
is in its uppermost position as shown in
FIG. 8
, the compression caps
50
and
51
are held in their sealing relation with the print heads of the ink cartridges
11
(see
FIG. 1
) and
12
, respectively. This prevents evaporation of ink from the print heads of the ink jet printer
10
.
When the controller of the ink jet printer
10
returns the carrier
14
to cooperate with the sheets
18
of paper media to again print thereon, the direction of the motor is reversed to move the carrier
14
to the left in FIG.
1
. As the carrier
14
moves to the left in
FIG. 1
, the spring
65
(see
FIG. 3
) causes the movable sled
22
to follow the motion of the carrier
14
(see FIG.
1
). The movable sled
22
is moving to the left in
FIG. 1
but to the right in FIG.
3
. When the movable sled
22
reaches the position of
FIG. 3
in which the pin
34
, for example, rests on the intermediate dwell
42
through movement of the movable sled
22
to the right in
FIG. 3
, a vertical surface
85
of the pawl
76
engages a vertical surface
86
on the arm
79
to stop movement of the movable sled
22
.
Continued motion of the carrier
14
to the left in
FIG. 1
towards the sheets
18
of paper media at which printing occurs results in the print heads on the ink cartridges
11
and
12
engaging wipers
87
and
88
, respectively. The wipers
87
and
88
are mounted on the movable sled
22
and extend above the tops of the caps
50
and
51
.
With the movable sled
22
in its intermediate position in which the pins or cam followers
31
,
32
,
34
(see FIG.
2
), and
35
are disposed on the intermediate flat dwell
42
(see
FIG. 11
) of the cam profile
38
, the wipers
87
(see
FIG. 1
) and
88
extend upwardly sufficiently to engage the print heads on the ink cartridges
11
and
12
, respectively. The wipers
87
and
88
have sufficient engagement with the print heads on the ink cartridges
11
and
12
, respectively, to wipe any excess ink from the nozzles forming the print head on each of the ink cartridges
11
and
12
.
After wiping is completed, the carrier
14
moves further to the left in
FIG. 1
(In
FIGS. 2 and 3
, the carrier
14
is moving to the right when it returns toward the print area) to cause a vertical surface
89
(see
FIG. 2
) on the back of the carrier
14
to engage a vertical surface
90
(see
FIG. 3
) on the upper end of a leg
91
of the latch
70
. Thus, engagement of the vertical surface
89
(see
FIG. 2
) on the carrier
14
with the vertical surface
90
(see
FIG. 3
) on the upper end of a leg
91
of the latch
70
causes the latch
70
to pivot clockwise about the pivot post
71
against the force of the return spring
65
to remove the vertical surface
85
of the pawl
76
from engagement with the vertical surface
86
on the arm
79
. This delatching or releasing of the latch
70
enables the spring
65
to move the movable sled
22
to the right in
FIGS. 2 and 3
(This is to the left in
FIG. 1.
) to its lowermost position.
When the latch
70
is released, the spring
65
(see
FIG. 4
) moves the front wall
30
of the movable sled
22
against the inner surface
74
of the front wall
24
of the support housing
21
. The friction of this engagement and damping by a viscous media such as grease, for example, on the inner surface
74
of the front wall
24
of the support housing
21
slow the downward movement of the movable sled
22
to its lowermost position. This absorbs energy of the force of the left (as viewed in
FIG. 1
) end of the movable sled
22
engaging the left end of the support housing
21
. This reduces the noise level of the ink jet printer
10
(see FIG.
1
).
The controller of the ink jet printer
10
causes motion of the carrier
14
to the right to align the print heads (not shown) on the cartridges
11
and
12
with rectangular shaped openings
92
(see
FIG. 4
) and
93
, respectively, in a bottom wall
94
of the movable sled
22
. Each of the openings
92
and
93
enables ejection of ink from each of the nozzles in the print heads of the ink cartridges
11
(see
FIG. 1
) and
12
to clear the nozzles. The ink passes through the openings
92
(see
FIG. 4
) and
93
into ink collection areas in the bottom of the ink jet printer
10
(see FIG.
1
).
After ink is ejected to clear the nozzles, the controller of the ink jet printer
10
causes the carrier
14
(see
FIG. 1
) to be moved to the left to return it for cooperation with the sheets
18
of paper media and the movable sled
22
has been returned to its lowermost position by the return spring
65
(see FIG.
3
), the controller of the ink jet printer
10
determines when there should be wiping of the print heads on the cartridges
11
and
12
and ejection of ink from the nozzles. This occurs after a certain amount of a print cycle has been completed but not all of the print cycle.
When this wiping and ejection of ink from the nozzles is to occur before the print cycle is completed and the print cycle could be completed before it is to occur, the carrier
14
again is moved to the right in
FIG. 1
to move the movable sled
22
to its intermediate position. This is the position in which the intermediate dwell
42
(see
FIG. 11
) of the cam profile
38
has the pins
31
(see FIG.
1
),
32
,
34
(see FIG.
2
), and
35
resting thereon.
With the movable sled
22
(see
FIG. 3
) in its intermediate position, the latch
70
is again latched. Then, the carrier
14
(see
FIG. 1
) is moved to the left in
FIG. 1
to move over the wipers
87
and
88
, which engage the print heads on the ink cartridges
11
and
12
, respectively.
Continued movement to the left in
FIG. 1
of the carrier
14
causes release of the latch
70
as previously discussed. Thereafter, the carrier
14
is again moved to the right after the movable sled
22
is in its lowermost position to eject ink from the nozzles and through the rectangular shaped openings
92
(see
FIG. 4
) and
93
in the bottom wall
94
of the movable sled
22
into the collection area.
If the movable sled
22
should be inadvertently moved upwardly to its intermediate position when the carrier
14
(see
FIG. 1
) is over the sheets
18
of paper media such as by jarring or a paper jam, for example, then the movable sled
22
could cause jamming with the carrier
14
when the carrier
14
is moved to the right in
FIG. 1
(left in FIG.
10
). To prevent this, the carrier
14
has an angled surface
95
(see
FIG. 10
) on its left (right in
FIG. 1
) end for engagement with an angled surface
96
on the upper end of the leg
91
of the latch
70
. The engagement of the angled surface
95
with the angled surface
96
causes clockwise pivoting of the latch
70
about the pivot post
71
against the force of the return spring
65
(see
FIG. 3
) to delatch or release the latch
70
(see FIG.
10
). This delatching or releasing of the latch
70
enables the latch
70
to return to its lowermost position by the force of the return spring
65
(see FIG.
3
).
The pins
31
(see FIG.
1
),
32
,
34
(see FIG.
2
), and
35
have been shown and described as being on the movable sled
22
and the cam slot
25
(see FIG.
1
), the cam slot
26
, the cam slot
28
(see FIG.
2
), and the cam surface
29
on the support housing
21
. However, it should be understood that this arrangement could be reversed so that the pins
31
(see FIG.
1
),
32
,
34
(see FIG.
2
), and
35
are on the movable sled
22
and the cam slot
25
(see FIG.
1
), the cam slot
26
, the cam slot
28
(see FIG.
2
), and the cam surface
29
are on the support housing
21
. It is only necessary for them to cooperate with each other.
The location of the latch
70
(see
FIG. 1
) towards the rear so that the latch
70
is behind the plane of the print heads of the ink cartridges
11
and
12
enables use with different designs of the ink cartridges
11
and
12
without having to change the location of the latch
70
. For example, the print heads may be made wider or longer without the position of the latch
70
having to be changed. Of course, the sizes of the support housing
21
, the movable sled
22
, the caps
50
and
51
, and the wipers
87
and
88
would have to be changed.
In
FIG. 13
, the shape of a curve
100
represents a cycloidal cam profile. The shape of a curve
101
is for a cam profile produced from a quadratic equation. The shape of a curve
102
is for a trapezoidal cam profile.
An advantage of this invention is that it requires less power than presently available maintenance or service stations. Another advantage of this invention is that it provides a more flexible maintenance station for a ink jet printer in that it accommodates different designs of ink jet cartridges. A further advantage of this invention is that it reduces the cost of the printer because a smaller motor may be utilized due to decreased power requirements. Still another advantage of this invention is that the noise level produced by the printer is decreased when the movable sled returns to its lowermost or home position.
For purposes of exemplification, a preferred embodiment of the invention has been shown and described according to the best present understanding thereof. However, it will be apparent that changes and modifications in the arrangement and construction of the parts thereof may be resorted to without departing from the spirit and scope of the invention.
Claims
- 1. A maintenance station for a printer having a movable bidirectional carrier and printing means mounted thereon including:a fixed support housing; a movable sled supported on said support housing for longitudinal movement relative thereto in opposite directions; cam means on said movable sled and said support housing cooperating with each other to cause said movable sled to move vertically in response to the longitudinal movement of said movable sled relative to said support housing in a first longitudinal directions said cam means including: a plurality of cam surfaces on one of said movable sled and said support housing; and a plurality of cam followers on the other of said movable sled and said support housing, each of said cam followers cooperating with one of said cam surfaces; first means supported by said movable sled for providing maintenance on a first area of the printing means in which said movable sled is subjected to a first sled operating force, applied thereto by movement of the carrier to move said movable sled, due to engagement of said first means with the first area of the printing means; second means supported by said movable sled for providing maintenance on the printing means in which said movable sled is subjected to a second sled operating force, applied thereto by movement of the carrier to move said movable sled, due to engagement of said second means with a second area of the printing means, the second sled operating force being greater than the first sled operating force, wherein each of said cam surfaces has a cam profile designed to maintain the second sled operating force substantially constant during upward movement of said movable sled, said cam profile of each of said cam surfaces being designed in accordance with a quadratic equation to enable application of a minimum and substantially constant second sled one rating force from the carrier to said movable sled for longitudinal movement thereof; resilient means acting between said movable sled and said support housing to continuously urge said movable sled in a second longitudinal direction opposite to the first direction in which said movable sled is moved by movement of the carrier, said resilient means including a spring having a second end fixed to said support housing and a first end fixed to said movable sled, in which said spring exerts a force at an angle to the longitudinal movement of said movable sled so as to apply a force continuously urging said movable sled in a direction perpendicular to the longitudinal movement of said sled to a predetermined position in addition to continuously urging said movable sled in the second longitudinal direction; and cooperating means on said movable sled and said support housing for holding said movable sled in a fixed position when said first means is providing maintenance in the first area of the printing means, said cooperating means including: holding means on said support housing; a latch pivotally mounted on said movable sled and engaging said holding means on said support housing; and said first end of said spring fixed to said latch to also urge said latch into engagement with said holding means on said support housing.
- 2. A maintenance station for a printer having a movable bidirectional carrier and printing means mounted thereon including:a fixed support housing; a movable sled supported on said support housing for longitudinal movement relative thereto in opposite directions; cam means on said movable sled and said support housing cooperating with each other to cause said movable sled to move vertically in response to the longitudinal movement of said movable sled relative to said support housing in a first longitudinal direction; a spring having a second end fixed to said support housing and a first end fixed to said movable sled to continuously urge said movable sled in a second longitudinal direction opposite to the first longitudinal direction in which said movable sled is moved by movement of the carrier; said spring exerting a force at an angle to the longitudinal movement of said movable sled to apply a first force to said movable sled in the second longitudinal direction and to apply a second force continuously urging said movable sled perpendicular to, and in the same plane as, the longitudinal movement of said movable sled to a predetermined position; means responsive to movement of said movable sled in the first longitudinal direction for moving said movable sled away from the predetermined position; and cooperating means on said movable sled and said support housing for holding said movable sled in a fixed position when a first means is providing maintenance in a first area of the printing means, wherein said cooperating means includes: holding means on said support housing; a latch pivotally mounted on said movable sled and engaging said holding means on said support housing; and said first end of said spring fixed to said latch to also urge said latch into engagement with said holding means on said support housing.
- 3. A maintenance station for a printer having a movable bidirectional carrier and printing means mounted thereon including:a fixed support housing; a movable sled supported on said support housing for longitudinal movement relative thereto in opposite directions; cam means on said movable sled and said support housing cooperating with each other to cause said movable sled to move vertically in response to the longitudinal movement of said movable sled relative to said support housing in a first longitudinal direction; a spring having a second end fixed to said support housing and a first end fixed to said movable sled to continuously urge said movable sled in a second longitudinal direction opposite to the first longitudinal direction in which said movable sled is moved by movement of the carrier; said spring exerting a force at an angle to the longitudinal movement of said movable sled to apply a first force to said movable sled in the second longitudinal direction and to apply a second force continuously urging said movable sled perpendicular to, and in the same plane as, the longitudinal movement of said movable sled to a predetermined position; and cooperating means on said movable sled and said support housing for holding said movable sled in a fixed position when a first means is providing maintenance in a first area of the printing means, wherein said cooperating means includes: holding means on said support housing; a latch pivotally mounted on said movable sled and engaging said holding means on said support housing; and said first end of said spring fixed to said latch to also urge said latch into engagement with said holding means on said support housing.
- 4. A maintenance station for a printer having a movable bidirectional carrier and printing means mounted thereon including:a fixed support housing; a movable sled supported on said support housing for longitudinal movement relative thereto in opposite directions; cam means on said movable sled and said support housing cooperating with each other to cause said movable sled to move vertically in response to the longitudinal movement of said movable sled relative to said support housing in a first longitudinal direction, said cam means including: a plurality of cam surfaces on one of said movable sled and said support housing; and a plurality of cam followers on the other of said movable sled and said support housing, each of said cam followers cooperating with one of said cam surfaces; first means supported by said movable sled for providing maintenance on a first area of the printing means in which said movable sled is subjected to a first sled operating force, applied thereto by movement of the carrier to move said movable sled, due to engagement of said first means with the first area of the printing means; second means supported by said movable sled for providing maintenance on the printing means in which said movable sled is subjected to a second sled operating force, applied thereto by movement of the carrier to move said movable sled, due to engagement of said second means with a second area of the printing means, the second sled operating force being greater than the first sled operating force, wherein each of said cam surfaces has a cam profile designed to maintain the second sled operating force substantially constant during upward movement of said movable sled; resilient means including a spring acting between said movable sled and said support housing to continuously urge said movable sled in a second longitudinal direction opposite to the first direction in which said movable sled is moved by movement of the carrier; and cooperating means on said movable sled and said support housing for holding said movable sled in a fixed position when said first means is providing maintenance in the first area of the printing means, said cooperating means including: holding means on said support housing; a latch pivotally mounted on said movable sled and engaging said holding means on said support housing; and a first end of said spring fixed to said latch to also urge said latch into engagement with said holding means on said support housing.
US Referenced Citations (3)
Foreign Referenced Citations (5)
Number |
Date |
Country |
297 16 190 U |
Nov 1997 |
DE |
0 604 067 |
Jun 1994 |
EP |
0 604 068 |
Jun 1994 |
EP |
0 720 912 |
Jul 1996 |
EP |
WO 9634754 |
Nov 1996 |
WO |