Information
-
Patent Grant
-
6386681
-
Patent Number
6,386,681
-
Date Filed
Tuesday, February 1, 200024 years ago
-
Date Issued
Tuesday, May 14, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Lambert; D. Brent
- Taylor; Todd T.
-
CPC
-
US Classifications
Field of Search
US
- 347 85
- 347 86
- 347 87
- 347 49
- 347 50
- 347 37
- 347 39
-
International Classifications
-
Abstract
The printhead unit is for an imaging apparatus having a guide member. The printhead unit is configured to be positioned in a carrier assembly within the imaging apparatus and is configured for movement within the imaging apparatus via the carrier assembly. The printhead unit includes a housing a printhead and at least one bearing. The housing has at least a first side member. The printhead is attached at least to the first side member of the housing. Further, the at least one bearing has at least one bearing surface, the at least one bearing being coupled to the first side member of the housing and positioned to engage the guide member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet printer, and more particularly, to an ink jet printhead carrier and one or more ink jet printhead assemblies associated therewith.
2. Description of the Related Art
Typical ink jet printers include a printer frame which defines a media path for a sheet of media. A sheet of print media is transported by a series of rollers along the media path through a print zone. In the print zone, one or more printheads eject ink onto the sheet at predefined locations to form an image thereon. The quality of the formed image is dependent, at least in part, on the tolerances and alignment of various components in the printing system.
Such a typical ink jet printer includes a printhead carrier for carrying the one or more printheads. The ink jet printer also includes one or more guide rods mounted to the printer to be positioned transverse to the direction of media travel. The guide rods guide the printhead carrier for reciprocating movement across the width of the sheet of print media. Typically, each printhead is mounted into a cradle within the printhead carrier. The carrier includes fixed bearings which contact a guide surface of each of the one or more guide rods.
Although this approach can provide adequate printing results, such an arrangement induces positioning and alignment errors between the physical location of the print nozzles of the printhead in relation to the position of the printhead carrier, and in relation to the one or more guide rods which position and support the printhead carrier. Such positioning and alignment errors translate into errors between the calculated location on the sheet of print media at which an ink dot is to be placed and the actual location at which the ink dot is placed, which in turn translates into decrease print quality.
SUMMARY OF THE INVENTION
In one aspect of the invention, an imaging apparatus includes a first side frame and a second side frame. A first guide rod extends between the first side wall and the second side wall and has a first surface and a first cross-sectional area. A second guide rod extends between the first side frame and the second side frame and is arranged parallel to the first guide rod. The second guide rod has a second surface and a second cross-sectional area. The imaging apparatus also includes a carrier assembly having a body, and a printhead interface unit attached to the body. A printhead unit is structured and adapted for mating engagement the printhead interface unit. The printhead unit has at least one bearing surface which contacts the first surface of the first guide rod and at least one second bearing surface which contacts the second surface of the second guide rod.
In another aspect of the invention, an imaging apparatus includes a first side frame and a second side frame. A first guide rod extends between the first side wall and the second side wall, wherein the first guide rod has a first surface and a first cross-sectional area. A second guide rod extends between the first side frame and the second side frame and is arranged parallel to the first guide rod. The second guide rod has a second surface and a second cross-sectional area. The imaging apparatus also includes a carrier assembly having a body, and a color printhead interface unit attached to the body. A color printhead unit is structured and arranged for mating engagement with the color printhead interface unit. The color printhead unit has a first bearing surface which contacts the first surface of the first guide rod and a first pair of V-shaped bearings defining four bearing surfaces which contact the second guide surface of the second guide rod.
Another aspect of the invention is a printhead unit for an imaging apparatus having a guide member. The printhead unit includes a housing, a printhead attached to the housing and at least one bearing having at least one bearing surface. The bearing is coupled to the housing and is positioned to engage the guide member.
Another aspect of the invention provides a printhead unit for an imaging apparatus having a first guide member and a second guide member. The printhead unit includes a housing; a printhead attached to the housing; a first bearing having a first bearing surface, the first bearing being coupled to the housing and positioned to engage the first guide member; and a second bearing having a second bearing surface, the second bearing being coupled to the housing and positioned to engage the second guide member.
An advantage of the present invention is that the carrier assembly is positioned relative to at least one printhead unit, thereby reducing positioning and alignment errors between the printhead unit and the carrier assembly.
Another advantage of the invention is that each printhead unit is directly positioned relative to the guide rod(s) of the imaging apparatus by locating guide rod bearings on each printhead unit, thereby eliminating the carrier as a factor in positioning and alignment errors between the printhead unit and the guide rod(s).
BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
FIG. 1
is a schematic illustration of an imaging apparatus embodying the present invention;
FIG. 2
is a perspective view of a carrier assembly of the present invention;
FIG. 3
is a perspective view of a color printhead assembly of the present invention;
FIG. 4
is a perspective view of a mono printhead assembly of the present invention; and
FIG. 5
is a side view of the carrier assembly and the printhead assemblies of the present invention with the carrier assembly secured to the printhead assemblies of the present invention.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings and particularly to
FIG. 1
, there is shown an imaging apparatus
10
, such as an ink jet printer, embodying the present invention. Imaging apparatus
10
includes a first side frame
12
, a second side frame
14
, a first guide rod
16
, a second guide rod
18
, a carrier assembly
20
, a color printhead assembly
22
, a mono (e.g., black) printhead assembly
24
and a drive belt
26
. As used hereinafter, positional terms such as for example, left, right, top, bottom, upper, lower, back front, etc., are used to aid the reader in understanding the invention as depicted in the various FIGS., and should not be considered terminology which limits the scope of the invention.
First guide rod
16
is attached to and extends between first side frame
12
and second side frame
14
. Preferably, first guide rod
16
is circular in cross-section and has a diameter of about 8 millimeters (mm). Also, first guide rod
16
has a smooth cylindrical surface
17
. Second guide rod
18
is attached to and extends between first side frame
12
and second side frame
14
. Preferably, second guide rod
18
is circular in cross-section and has a diameter of about 12 mm. Second guide rod
18
has a smooth cylindrical surface
19
.
As can be best seen in
FIG. 5
, in relation to
FIG. 1
, first guide rod
16
is positioned to have both a vertical offset and a horizontal offset in relation to second guide rod
18
. In
FIG. 5
, a portion of mono printhead assembly
24
is broken away to expose a portion of color printhead assembly
22
. In the component orientation shown in
FIG. 5
, first guide rod
16
is positioned generally in front of printhead assemblies
22
24
, and second guide rod
18
is positioned to be beneath printhead assemblies
22
,
24
, and beneath carrier assembly
20
. When printhead assemblies
22
,
24
are not mounted in imaging apparatus
10
, carrier assembly
20
is loosely mounted in imaging apparatus
10
via first guide rod
16
, and rests by the effects of gravity on first guide rod
16
and second guide rod
18
.
Referring now to
FIG. 2
, carrier assembly
20
includes a body
28
, a latching mechanism
30
, a color card assembly
32
and a mono card assembly
33
.
Body
28
defines a color receptacle
34
for mounting color printhead assembly
22
and a mono receptacle
36
for mounting mono printhead assembly
24
. Body
28
includes a front wall
38
, a back wall
40
, a side wall
42
, an opposing side wall
44
and a middle side wall
46
. Front wall
38
, back wall
40
, and side walls
42
,
44
are arranged to form a substantially rectangular structure. Middle side wall
46
is located within body
28
to define the general size of each of color receptacle
34
and mono receptacle
36
. Thus, color receptacle
34
is defined, in part, by walls
38
,
40
,
42
,
46
, and mono receptacle
36
is generally defined, in part, by walls
38
,
40
,
44
and
46
. However, mono receptacle
36
includes an inner frame
48
which is mechanically coupled to front wall
38
, and loosely coupled to side frame
44
, as will be further described below, to facilitate alignment of mono printhead assembly
24
independent of the alignment of color printhead assembly
22
. Body
28
includes a passage
50
having a first opening
52
and a second opening
54
for loosely receiving first guide rod
16
.
Side wall
42
includes a base portion
56
and an extension portion
58
which extends upwardly from base portion
56
. Base portion
56
includes a surface
60
, an axle hole
62
, a carrier stop member
64
A and a spacing boss
65
. Extension portion
58
includes a pivot slot
66
, a passage hole
68
, a first locator (index) indention
70
and a second locator indention
71
.
Opposing side wall
44
includes a base portion
72
and an extension portion
74
which extends upwardly from base portion
72
. Base portion
72
includes a surface
76
, an axle slot
78
, a guide slot
80
, and a door
82
which actuates a plurality of biasing springs
84
. Guide slot
80
extends generally perpendicularly downward from surface
76
into base portion
72
. Second extension portion
74
includes a pivot slot
86
and a passage hole
88
.
Middle side wall
46
includes a base portion
90
and an extension portion
92
which extends upwardly from base portion
90
. Base portion
90
includes an axle hole
94
A facing color receptacle
34
and a carrier stop member
64
B which faces color receptacle
34
. Middle extension portion
92
includes a passage hole
98
.
Referring to
FIG. 2
, inner frame
48
is a generally rectangular structure and includes an axle hold
94
B located near middle side wall
46
, and an axle hole
99
which is located on an opposing wall of rectangular inner frame
48
. Axle hole
99
is positioned to be generally in alignment with a portion of axle slot
78
of side wall
44
. Inner frame
48
further includes a pair of carrier stop members
96
A,
96
B (see
FIGS. 2
and
5
) which are positioned on opposing side walls of the rectangular structure of inner frame
48
.
As shown in
FIG. 2
, passage
50
includes passage holes
68
,
88
and
98
of side walls
42
,
44
and
46
, respectively. Passage holes
68
,
88
,
98
have a cross-sectional area larger than the cross-sectional area of guide rod
16
so as to enable carrier assembly
20
to be positioned such that guide rod
16
is not contacted by carrier assembly
20
. As shown, passage holes
68
,
88
,
98
are located near front wall
38
of body
28
.
Axle holes
62
,
94
A are arranged in body
28
to be coaxial with respect to an axis
100
A, and axle holes
94
B,
99
are arranged in inner frame
48
to be coaxial with axis
100
B. Axle holes
62
,
94
A,
94
B and
99
are arranged to be near back wall
40
of body
28
. Body
28
further defines a recessed region
102
defined by arc surfaces
104
,
106
,
108
formed on the under side of base portions
56
,
72
,
90
of side walls
42
,
44
,
46
, respectively. Recessed region
102
is located to accommodate guide rod
18
.
Alternatively, inner frame
48
can be made integral with the walls defining mono receptacle
36
. In such a case, axle hole
94
B and carrier stop
96
A would become a part of middle side wall
46
, and axle hole
99
and carrier stop
96
B would become part of side wall
44
. However, in such an arrangement, the ability to independently align color printhead assembly
22
and mono printhead assembly
24
would be diminished.
Latching mechanism
30
is structured and adapted for pivotal mounting to body
28
. Latching mechanism
30
includes a U-shaped handle
110
, a color bail
112
and a mono bail
114
.
U-shaped handle
110
is defined by a first member
116
and a second member
118
which are spaced apart and extend in parallel from a bridge member
120
. First member
116
has a first distal end
122
for engaging pivot slot
66
of body
28
, and second member
118
has a second distal end
124
for engaging pivot slot
86
of body
28
. First member
116
has a mid-portion
126
having a pivot hole
128
formed therein. Second member
118
has mid-portion
130
having a pivot hole
132
formed therein. Located near pivot hole
128
is a downwardly extending guide member
133
A which is positioned to engage a slot (not shown) located near surface
60
of side wall
47
. Located near pivot hole
132
is downwardly extending guide member
133
B which is positioned and sized for mating engagement with guide slot
80
.
Color bail
112
has a first axle portion
134
A, a second axle portion
136
A, a lever portion
138
A and a latching portion
140
A. First axle portion
134
A is spaced apart and coaxial with second axle portion
136
A along axis
100
A. Latching portion
140
A is formed between and extends outwardly away from first axle portion
134
A and second axle portion
136
A. First axle portion
134
A is positioned in axle hole
62
of body
28
and second axle portion
136
A is positioned in axle hole
94
A of body
28
.
Likewise, mono bail
114
has a first axle portion
134
B, a second axle portion
136
B, a lever portion
138
B and a latching portion
140
B. First axle portion
134
B is spaced apart and coaxial with second axle portion
136
B along axis
100
B. Latching portion
140
B is formed between and extends outwardly away from first axle portion
134
B and second axle portion
136
B. First axle portion
134
B is positioned in axle hole
99
of inner frame
48
and second axle portion
136
A is positioned in axle hole
94
B of inner frame
48
.
Each of the lever portions
138
A,
138
B extend outwardly away from axes
100
A,
100
B, respectively. Lever portion
138
A of color bail
112
has an extended end defining a pivot portion
142
A positioned for engaging pivot hole
128
of handle
110
. The extent of lever portion
138
A from axis
100
A is selected to be greater than an extent of latching portion
140
A from axis
100
A. Likewise, lever portion
138
B of mono bail
114
has an extended end defining a pivot portion
142
B positioned for engaging pivot hole
132
of handle
110
. The extent of lever portion
138
B from axis
100
B is selected to be greater than an extend of latching portion
140
B from axis
100
B. Preferably, the extents of lever portions
138
A and
138
B are substantially equal. Each of lever portions
138
A,
138
B have an angular shape, which is commonly referred to as a “dog leg” shape.
Color card assembly
32
provides both electrical and mechanical connection to color printhead assembly
22
. Color card assembly
32
is attached to front wall
38
of carrier assembly
20
. Color card assembly
22
includes a color circuit card
144
A and a color printhead interface assembly
146
A. Color circuit card
144
A includes electrical connectors and printed circuits (not shown) which facilitates electrical communication between the printer controller (not shown) of imaging apparatus
10
and color printhead interface assembly
146
A. Color circuit car
144
A also includes a pair of locator pins
148
,
150
which are sized and positioned for mating engagement with corresponding locator indentions
70
,
71
, respectively, of side wall
42
in color receptacle
34
.
Color printhead interface assembly
146
A is electrically and mechanically connected to color circuit card
144
A. Color printhead interface assembly
146
A (commonly referred to as a pogo pin assembly) includes a plurality of spring-loaded pin conductors
147
A which provide positive electrical connection to the electrical circuits of the color printheads of color printhead assembly
22
. Color printhead interface assembly
146
A further includes a pair of alignment bosses
152
A,
154
A.
Mono card assembly
33
provides electrical connection to mono printhead assembly
24
, and accommodates mechanical alignment of mono printhead assembly
24
therewith. In preferred embodiments, mono card assembly
33
is attached to inner frame
48
prior to attachment to front wall
38
. Mono card assembly
33
includes a mono circuit card
144
B and a mono printhead interface assembly
146
B. Mono circuit card
144
B includes electrical connectors and printed circuits (not shown) which facilitates electrical communication between the printer controller (not shown) of imaging apparatus
10
and mono printhead interface assembly
146
B.
Mono printhead interface assembly
146
B is electrically and mechanically connected to mono circuit card
144
B. Mono printhead interface assembly
146
B (e.g., a pogo pin assembly) includes a plurality of spring-loaded pin conductors
147
B which provide positive electrical connection to the electrical circuits of the mono printhead of mono printhead assembly
24
. Mono printhead interface assembly
146
B further includes a pair of alignment bosses
152
B,
154
B.
Referring now to
FIG. 3
, color printhead assembly
22
is structured and adapted for mating engagement with color printhead interface assembly
146
A. Color printhead assembly
22
includes a color printhead unit
156
and a plurality of detachable ink reservoirs
158
. Color printhead unit
156
includes a base
160
, a rear wall
161
, a mounting wall
162
, a pair of side walls
163
and an extension member
164
. Mounting wall
162
has a first end portion
166
, a second end portion
168
and a face surface
170
.
Base
160
and side walls
163
extends substantially perpendicularly away from mounting wall
162
to define, in part, a housing
172
for receiving detachable ink reservoirs
158
. Base
160
also has a distal end
174
near which rear wall
161
is located. Distal end
174
and rear wall
161
extend across the width of base
160
to define a latching lip surface
176
.
As shown in
FIG. 3
, preferably, base
160
further includes a pair of V-shaped bearings
178
A,
178
B which are attached to a bottom surface
180
of base
160
near distal end
174
, and are spaced apart along a center line
182
. V-shaped bearings
178
A,
178
B include a plurality of bearing members
184
A,
184
B and
184
C,
184
D, respectively. Bearing members
184
A,
184
B,
184
C, and
184
D define a corresponding plurality of bearing surfaces
186
A,
186
B,
186
C, and
186
D for contacting surface
19
of guide rod
18
. Accordingly, V-shaped bearings
178
A,
178
B define at least four points of contact with surface
19
of guide rod
18
, with bearing surfaces
186
A,
186
C located on one side of centerline
182
. Centerline
182
represents a location in space which is equidistant from bearing surfaces
186
A,
186
B,
186
C,
186
D at its closest point associated with the respective bearing surface. A plane extending perpendicularly downward from bottom surface
180
which passes through centerline
182
would also pass through the center region of guide rod
18
. Thus, bearing surfaces
186
A,
186
B and bearing surfaces
186
C,
186
D are arranged and located to permit relatively unrestricted movement of color printhead assembly
22
in a direction corresponding to the extent of centerline
182
, while restricting movement of color printhead assembly
22
in directions normal to centerline
182
within the downward extent of bearing members
184
A,
184
B,
184
C,
184
D.
Alternatively, each of bearing members pairs
184
A,
184
B and
184
C,
184
D could be combined and/or located to effectively form a single V-shaped bearing structure. Also, in some applications it may be desired to use a single bearing, such as V-shaped bearing
178
A, which is centrally located on base surface
180
along center line
182
. Also, alternatively, in some applications it may be desirable to only use a single bearing surface, or a spaced apart pair of single bearing surfaces, to contact surface
19
of guise rod
18
at one or two locations, respectively.
Mounting wall
162
includes a pair of alignment apertures
188
,
190
which extend inwardly from face surface
170
. Preferably, alignment aperture
188
is a circular hole and alignment aperture
190
is a tapered slotted hole. Alignment aperture
188
and alignment aperture
190
are sized and positioned for mating engagement with alignment bosses
152
A,
154
A, respectively, of color card assembly
32
. Alignment aperture
190
is slotted to aid in the initial engagement with boss
154
A.
A printhead extension
192
extends generally perpendicularly from the furthermost region of portion
168
of mounting wall
162
toward centerline
182
. On printhead extension
192
is mounted a plurality of color printheads
194
, each having a plurality of ink emitting nozzles. Attached to mounting wall
162
and wrapping around to printhead extension
192
is a plurality of color tape automated bonding (TAB) circuits
196
having electrical contact pads
198
arranged for corresponding engagement with spring loaded pin conductors
147
A of color printhead interface assembly
146
A. TAB circuits
196
include conductor paths (not shown) which are in electrical communication with corresponding ink emitting actuators associated with the plurality of ink emitting nozzles of printheads
194
.
Extension member
164
extends substantially perpendicularly away from face surface
170
at first end portion
166
in a direction opposite to the extent of base
160
. A bearing protrusion
200
extends perpendicularly downward from extension
164
to define a bearing surface
202
. Preferably, bearing surface
202
is a single bearing surface which is curved to minimize the area of contact between bearing surface
202
and surface
17
of guide rod
16
. Also, it is contemplated that the general bearing structure of bearing surface
202
could be modified to form one or more V-shaped bearing surfaces similar to that of bearings
178
A,
178
B.
In a preferred construction of color printhead unit
156
, bearings
178
A,
178
B and
200
are formed from an abrasion resistant plastic having a low coefficient of friction. In fabricating color printhead
156
, the combination of base
160
, mounting wall
162
, side walls
163
and extension member
164
form an aluminum frame to which plastic bearings
178
A,
178
B and
200
are molded. Alternatively, the entire color printhead unit
156
could be made of plastic and fabricated by an injection molding process.
Referring now to
FIG. 4
, mono printhead assembly
24
is structured and adapted for mating engagement with mono printhead interface assembly
146
B. Mono printhead assembly
24
includes a mono printhead unit
256
and a detachable mono ink reservoir
258
. Mono printhead unit
256
includes a base
260
, a rear wall
261
, a mounting wall
262
, a pair of side walls
263
and an extension member
264
. Mounting wall
262
has a first end portion
266
, a second end portion
268
and a face surface
270
.
Base
260
and side walls
263
extend substantially perpendicularly away from mounting wall
262
to define, in part, a housing
272
for receiving detachable mono ink reservoir
258
. Base
260
also has a distal end
274
near which rear wall
261
is located. Distal end
274
and rear wall
261
extend across the width of base
260
to define a latching lip surface
276
. Extending outwardly from the side wall
263
which will be positioned closest to color printhead unit
156
is a spacer member
277
.
As shown in
FIG. 4
, preferably, base
260
further includes a pair of V-shaped bearings
278
A,
278
B which are attached to a bottom surface
280
of base
260
near distal end
274
, and are spaced apart along center line
282
. V-shaped bearings
278
A,
278
B are formed by a plurality of bearing members
284
A,
284
B and
284
C,
284
D, respectively. Bearing members
284
A,
284
B,
284
C, and
284
D define a corresponding plurality of bearing surfaces
286
A,
286
B,
286
C, and
286
D for contacting surface
19
of guide rod
18
. Thus, bearing surfaces
286
A,
286
B are arranged and located to form a V-shaped bearing surface of bearing
278
A. Likewise, bearing surfaces
286
C,
286
D are arranged and located to form a V-shaped bearing surface of bearing
278
B. Accordingly, V-shaped bearings
278
A,
278
B define at least four points of contact with surface
19
of guide rod
18
, with bearing surfaces
286
A,
286
C located on one side of centerline
282
and with bearing surfaces
286
B,
286
D located on an opposing side of centerline
282
. Centerline
282
represents a location in space which is equidistant from bearing surfaces
286
A,
286
B,
286
C,
286
D at its closest point associated with the respective bearing surface. A plane extending perpendicularly downward from bottom surface
280
which passes through centerline
282
would also pass through the center region of guide rod
18
. Thus, bearing surfaces
286
A,
286
B and bearing surfaces
286
C,
286
D are arranged and located to permit relatively unrestricted movement of mono printhead assembly
24
in a direction corresponding to the extent of centerline
282
, while restricting movement of mono printhead assembly
24
in directions normal to centerline
282
within the downward extent of bearing members
284
A,
284
B,
284
C,
284
D.
Alternatively, each of bearing member pairs
284
A,
284
B and
284
C,
284
D could be combined and/or located to effectively form a single V-shaped bearing structure. Also, in some applications it may be desired to use a single bearing, such as V-shaped bearing
278
A, which could be centrally located on base surface
280
with respect to center line
282
. Alternatively, in some applications it may be desirable to only use a single bearing surface, or a spaced apart pair of single bearing surfaces, to contact guide rod
18
.
Mounting wall
262
includes a pair of alignment apertures
288
,
290
which extend inwardly from face surface
270
. Preferably, alignment aperture
288
is a circular hole and alignment aperture
290
is a tapered slotted hole. Alignment aperture
288
and alignment aperture
290
are sized and positioned for mating engagement with alignment bosses
152
B,
154
B of mono card assembly
33
. Alignment aperture
290
is slotted to aid in the initial engagement with boss
154
B.
A printhead extension
292
extends generally perpendicularly from mounting wall
292
. On printhead extension
292
is mounted a mono printhead
294
having a plurality of ink emitting nozzles. Attached to mounting wall
262
and wrapping around a printhead extension
292
is a mono TAB circuit
296
having electrical contact pads
298
arranged for corresponding engagement with spring loaded pin conductors
147
B of mono printhead interface assembly
146
B. TAB circuit
296
includes conductor paths (not shown) which are in electrical communication with corresponding ink emitting actuators associated with the plurality of ink emitting nozzles of printhead
294
.
Extension member
264
extends substantially perpendicularly away from face surface
270
at first end portion
266
in a direction opposite to the extent of base
260
. A bearing protrusion
300
extends perpendicularly from extension
164
to define a bearing surface
302
. Preferably, bearing surface
302
is a single bearing surface which is curved to minimize the area of contact between bearing surface
302
and surface
17
of guide rod
16
. In some applications, it may be desirable to use a plurality of single bearing surfaces, such as a spaced pair of single bearing surfaces, to contact surface
17
of guide rod
16
. Also, it is contemplated that the general bearing structure of bearing surface
302
could be modified to form one or more V-shaped bearing surfaces, such as that represented by V-shaped bearings
278
A,
278
B.
In a preferred construction of mono printhead unit
256
, bearings
278
A,
278
B and
300
are formed from an abrasion resistant plastic having a low coefficient of friction. In fabricating mono printhead
256
, the combination of base
260
, mounting wall
262
, side walls
263
and extension member
264
form an aluminum frame to which plastic bearings
178
A,
278
B and
300
are molded. Alternatively, the entire mono printhead unit
256
could be made of plastic and fabricated by an injection molding process.
Referring to
FIGS. 2 and 5
, latch mechanism
30
is structured and arranged to be movable between a non-latched position (as depicted in
FIG. 2
) and a latched position (as depicted in FIG.
5
).
When latch mechanism
30
is positioned in the non-latched position, carrier assembly
20
is supported by surface
17
of guide rod
16
at the portion of carrier assembly
20
which surrounds passage
50
. Also, surface
19
of guide rod
18
supports a portion of carrier assembly
20
located near recessed region
102
. While in the non-latched position, color printhead assembly
22
and/or mono printhead assembly
24
can be removed or installed. Assuming an initial condition in which no printhead assembly is installed on carrier assembly
20
, while in the non-latched position the user inserts color printhead assembly
22
and mono printhead assembly
24
into color receptacle
34
and mono receptacle
36
, respectively, of carrier
20
.
Latching mechanism
30
is structured and arranged to facilitate an over-center latching to effectively mount carrier assembly
20
to color printhead unit
156
of color printhead assembly
22
. Mono printhead assembly
24
is effectively mounted to carrier assembly
20
via inner frame
48
such that mono printhead assembly
24
follows guide rods
16
,
18
independent of color printhead assembly
22
. During latching, color printhead assembly
22
and mono printhead assembly
24
will engage color printhead interface assembly
146
A with mono printhead interface assembly
146
B, respectively, of carrier assembly
20
. When latch mechanism
30
is moved to the latched position, as shown in
FIG. 5
, carrier assembly
20
is lifted to be positioned out of contact with first guide rod
16
and seconded guide rod
18
, and carrier assembly
20
is supported in relation to guide rods
16
,
18
by color printhead assembly
22
, with the entire unit (i.e. carrier assembly
20
, color printhead assembly
22
, and mono printhead assembly
24
) positioned relative to guide rods
16
and
18
by color printhead bearings
178
A,
178
B and
200
of color printhead assembly
22
and mono printhead bearings
278
A,
278
B and
300
of mono printhead assembly
24
(see FIG.
3
).
Referring again to
FIG. 2
, during latching handle
110
is rotated forward in the direction depicted by arrows
304
A,
304
B until first and second distal ends
122
,
124
of handle
110
engage pivot slots
66
,
86
, respectively. During this rotation, several actions occur substantially simultaneously. As latching portions
140
A,
140
B of bails
112
,
114
contact rear wall
161
and latching lip surface
176
of color printhead assembly
22
, and rear wall
261
and latching lip surface
276
of mono printhead assembly
24
, respectively, carrier assembly
20
begins to move toward printhead assemblies
22
,
24
. As this movement occurs, color alignment bosses
152
A,
154
A and mono alignment bosses
152
B,
154
B engage alignment apertures
188
,
190
of color printhead unit
156
and alignment apertures
288
,
290
of mono printhead unit
256
, respectively. This in turn lifts the front portion of carrier assembly
20
to provide clearance between guide rod
16
and carrier
20
at passage
50
.
As handle
110
is then rotated downward in the direction of arrow
306
, the color bail
112
and mono bail
114
continue their movement to their final position, as shown in FIG.
5
. During this downward rotation, an over-centering event occurs. This over-centering lifts the back end of carrier
20
so as to provide clearance between the recessed portion
102
of carrier
20
and surface
19
of guide rod
18
. Since the interface assemblies
146
A,
146
B apply a force which opposes the force applied by the latching portions
140
A,
140
B through printhead assemblies
22
,
24
, secure mating of carrier
20
to printhead assemblies
22
,
24
occurs. Carrier stop members
64
A,
64
B and
96
A,
96
B of carrier assembly
20
limit the amount that carrier assembly
20
may rotate toward color printhead assembly
22
and mono printhead assembly
24
, respectively. Simultaneously, guide members
133
A,
133
B of handle
110
engage the respective guide slots of body
28
. Also, in turn, this motion rotates door
82
towards springs
84
to apply a force against mono printhead assembly
24
, which in turn causes spacer member
277
of mono printhead assembly
24
to contact an adjacent side wall
163
of color printhead assembly
22
, which in turn biases color printhead assembly
22
against spacing boss
65
located on side wall
42
of carrier body
28
. Thus, once the latching process is completed, color printhead assembly
22
and mono printhead assembly
24
are properly aligned with carrier assembly
20
for printing.
In order to assure proper alignment of printhead assemblies
22
,
24
with corresponding interface assemblies
146
A,
146
B, color card assembly
32
and mono card assembly
33
are attached to carrier assembly
20
in the manner described below. Color printhead interface assembly
146
A is attached to color circuit card
144
A at a predetermined location such that alignment bosses
152
A,
154
A are in proper orientation with respect to locator pins
148
,
150
. Color card assembly
32
is then inserted into receptacle
34
and positioned to be adjacent front wall
38
. In addition, color card assembly
32
is positioned adjacent to side wall
42
, such that locator pins
148
,
150
engage corresponding locator indentions
70
,
71
, respectively. Once color card assembly
32
is properly positioned with respect to side wall
42
, color card assembly
32
is mounted to front wall
38
using fasteners, such as for example, screws. Thereafter, mono card assembly
33
is positioned relative to color card assembly
32
, and mounted to front wall
38
using fasteners.
During printing, carrier assembly
20
is moved in a reciprocating manner in relation to guide rods
16
,
18
by forces exerted by a carrier drive unit (not shown) via drive belt
26
. However, carrier assembly
20
does not contact guide rods
16
,
18
. Rather, bearings positioned on printhead assemblies
22
,
24
contact guide rods
16
,
18
.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of this invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
Claims
- 1. An imaging apparatus, comprising:a first side frame; a second side frame; a first guide rod extending between said first side frame and said second side frame, said first guide rod having a first surface and a first cross-sectional area; a second guide rod extending between said first side frame and said second side frame and arranged parallel to said first guide rod, said second guide rod having a second surface and a second cross-sectional area; a carrier assembly having a body and having a printhead interface unit attached to said body and a printhead unit structured and adapted for mating engagement said printhead interface unit, said printhead unit having at least one bearing surface which contacts said first surface of said first guide rod and at least one second bearing surface which contacts said second surface of said second guide rod.
- 2. The imaging apparatus of claim 1, wherein said body has a passage which receives said first guide, said passage having a cross-sectional area which is larger than said first cross-sectional area, and wherein said carrier assembly further comprises a latch mechanism coupled to said body, said latch mechanism being movable between a non-latched position and a latched position, wherein said latch mechanism is structured and arranged so that when said latch mechanism is positioned in said latched position, said carrier assembly is moved to be positioned out of contact with said first guide rod and said second guide rod.
- 3. The imaging apparatus of claim 1, wherein said carrier assembly further comprises a latch mechanism coupled to said body, said latch mechanism being movable between a non-latched position and a latched position, wherein said latch mechanism is structured and arranged so that when said latch mechanism is positioned in said latched position, said carrier assembly is moved to be positioned out of contact with said first guide rod and said second guide rod.
- 4. The imaging apparatus of claim 3, wherein said latch mechanism is structured and arranged so that when said latch mechanism is positioned in said non-latched position, said carrier assembly is supported by said first surface of said first guide rod and by said second surface of said second guide rod.
- 5. The imaging apparatus of claim 1, further comprising a latching mechanism structured and arranged for pivotal mounting to said body.
- 6. The imaging apparatus of claim 1, wherein said body includes a first wall, a second wall, a third wall, a fourth wall, a first extension portion and a second extension portion, said first wall having a first wall portion having a first axle hole formed therein, said second wall having a second side wall portion having a second axle hole formed therein, said first extension portion including a first pivot slot and said second extension portion including a second pivot slot.
- 7. The imaging apparatus of claim 6, further comprising a latching mechanism including a handle having substantially a U-shape defined by a first member and a second member which are spaced apart and extend in parallel from a bridge member, said first member having a first distal end for engaging said first pivot slot of said body and said second member having a second distal end for engaging said second pivot slot of said body.
- 8. The imaging apparatus of claim 7, wherein said first member includes a first mid-portion having a first pivot hole formed therein, said latching member further comprising a first bail having a first axle portion, a second axle portion, a first lever portion, and a first latching protion, said first axle portion being spaced apart and coaxial with said second axle portion along a first axis and said first latching portion being formed between and extending outwardly away from said first axle portion and said second axle portion, said first axle portion being positioned in said first axle hole of said body and said second axle portion being positioned in said second axle hole of said body, and wherein said first lever portion extends outwardly away from said axis, said first lever portion having a first extended end defining a first pivot portion which is positioned in said first pivot hole of said handle.
- 9. The imaging apparatus of claim 8, wherein a first extent of said first lever portion of said first bail from said axis is greater than a second extent of said first latching portion of said first bail from said axis.
- 10. The imaging apparatus of claim 1, wherein said printhead unit comprises:a mounting wall having a first end portion, a second end portion and a face surface; a first member extending outwardly from said face surface at said first end portion of said mounting wall, said first member including said first bearing surface; and a base including said second bearing surface.
- 11. The imaging apparatus of claim 10, wherein said first bearing surface is defined by at least one bearing protrusion extending outwardly from said first member.
- 12. The imaging apparatus of claim 10, wherein said second bearing surface is defined by at least one of a first plurality of bearing members.
- 13. The imaging apparatus of claim 1, wherein said second bearing surface corresponds to a V-bearing surface of a V-shaped bearing.
- 14. The imaging apparatus of claim 1, wherein said body includes a plurality of V-shaped bearings, wherein said second bearing surface corresponds to at least one bearing surface of said plurality of V-shaped bearings and wherein each of said plurality of V-shaped bearings defines at least two bearing surfaces which contact said second surface of said second guide rod.
- 15. The imaging apparatus of claim 14, wherein said plurality of V-shaped bearings defines at least four bearing surfaces which contact with said second surface of said second guide rod.
- 16. The imaging apparatus of claim 1, wherein said printhead unit includes a mounting wall having at least one alignment aperture formed therein.
- 17. The imaging apparatus of claim 16, wherein said printhead interface unit includes at least one alignment boss, each said at least one alignment boss being positioned for mating engagement with a corresponding one of said at least one alignment aperture.
- 18. The imaging apparatus of claim 1, wherein said body includes a first wall, a second wall, a third wall, a fourth wall, said first wall having a first carrier stop member extending toward said third wall, wherein said first carrier stop member limits an extent of engagement of said carrier assembly with said printhead unit.
- 19. The imaging apparatus of claim 1, further comprising a circuit card which mounts said printhead interface unit to said body, said body defining a printhead receptacle having a first wall, said first wall including at least two indexing indentions, said circuit card including a corresponding at least two alignment pins structured and arranged for mating engagement with said at least two indexing indentions.
- 20. An imaging apparatus, comprising:a first side frame; a second side frame; a first guide rod extending between said first side frame and said second side frame, said first guide rod having a first surface and a first cross-sectional area; a second guide rod extending between said first side frame and said second side frame and arranged parallel to said first guide rod, said second guide rod having a second surface and a second cross-sectional area; a carrier assembly having a body and having a color printhead interface unit attached to said body; a color printhead unit structured and arranged for mating engagement with said color printhead interface unit, said color printhead unit having a first bearing surface which contacts said first surface of said first guide rod and a first pair of V-shaped bearings defining four bearing surfaces which contact said second guide surface of said second guide rod.
- 21. The imaging apparatus of claim 20, further comprising:a mono printhead interface unit attached to said body; and a mono printhead unit structured and arranged for mating engagement said mono printhead interface unit, said mono printhead unit having a second bearing surface which contacts said first surface of said first guide rod and a second pair of V-shaped bearings defining four bearing surfaces which contact said second guide surface of said second guide rod.
- 22. The imaging apparatus of claim 21, wherein said carrier assembly further comprises a latch mechanism pivotally coupled to said body, said latch mechanism being movable between a non-latched position and a latched position, wherein said latch mechanism is structured and arranged so that when said latch mechanism is positioned in said latched position, said carrier assembly is moved to be positioned out of contact with said first guide rod and said second guide rod.
- 23. The imaging apparatus of claim 22, wherein said latch mechanism is structured and arranged so that when said latch mechanism is positioned in said non-latched position, said carrier assembly is supported by said first surface of said first guide rod and by said second surface of said second guide rod.
- 24. A printhead unit for an imaging apparatus having a guide member, comprising:a housing having at least a first side member; a printhead attached at least to said first side member of said housing; and at least one bearing having at least one bearing surface, said bearing coupled to said first side member of said housing and positioned to engage said guide member.
- 25. The printhead unit of claim 24, wherein said at least one bearing surface has a curved shape.
- 26. The printhead unit of claim 24, wherein said at least one bearing includes a plurality of bearing surfaces for engaging said guide member.
- 27. The printhead unit of claim 26, wherein said plurality of bearing surfaces defines at least two bearing surfaces arranged in a V-shaped configuration.
- 28. The printhead unit of claim 26, wherein said plurality of bearing surfaces defines at least four bearing surfaces.
- 29. The printhead unit of claim 28, wherein said four bearing surfaces are arranged to form two V-shaped bearing configurations.
- 30. The printhead unit of claim 24, wherein said first side member is one of a base and a wall.
- 31. A printhead unit for an imaging apparatus having a first guide member and a second guide member comprising:a housing having at least a first side member and a second side member; a printhead attached to said housing; a first bearing having a first bearing surface, said first bearing being coupled to said first side member of said housing and positioned to engage said first guide member; and a second bearing having a second bearing surface, said second bearing being coupled to said second side member of said housing and positioned to engage said second guide member.
- 32. The printhead unit of claim 31, wherein said first bearing surface has a curved shape.
- 33. The printhead unit of claim 31, wherein said second bearing includes a third bearing surface for engaging said second guide member.
- 34. The printhead unit of claim 33, wherein said second bearing surface and said third bearing surface are arranged in a V-shaped configuration.
- 35. The printhead unit of claim 33, further comprising a third bearing having a fourth bearing surface and a fifth bearing surface, wherein said second bearing surface and said third bearing surface are arranged in a first V-shaped configuration and wherein said fourth bearing surface and said fifth bearing surface are arranged in a second V-shaped configuration.
- 36. The printhead unit of claim 31, wherein said first side member is a base and second side member is a wall.
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A |
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A |
5539436 |
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A |
5600350 |
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A |
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