Information
-
Patent Grant
-
6234472
-
Patent Number
6,234,472
-
Date Filed
Thursday, October 28, 199925 years ago
-
Date Issued
Tuesday, May 22, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 271 194
- 271 197
- 347 104
- 347 164
- 347 197
- 347 215
- 347 264
- 346 136
-
International Classifications
-
Abstract
A hardcopy apparatus comprising a main roller and an outputting mechanism for moving a medium outside the hardcopy apparatus, said outputting mechanism being characterised by including a vacuum holddown output unit for holding at least a portion of media down onto a surface of the outputting mechanism. In addition, a method of outputting a medium from a hardcopy apparatus including a vacuum source, a main driving roller and a secondary roller, includes the steps of: advancing the medium up to contact said secondary roller; generating a negative pressure, by means of the vacuum source, capable of engaging the back of the medium with the surface of the secondary roller: by rotating the main roller and the secondary roller, disengaging the medium from the main roller; and by rotating the secondary roller, advancing the medium towards the outside of the apparatus.
Description
FIELD OF THE INVENTION
The present invention generally relates to hardcopy apparatus, such as copiers, printers, scanners, facsimiles, and more particularly to improved media holddown devices for such apparatus.
BACKGROUND OF THE INVENTION
In hardcopy apparatus and particularly in apparatus handling media of big size, such as large format printers, printed media is outputted towards the outside of the printer by means of outputting means which may damage the quality of the printout. Conventional outputting means, in order to advance the printed media, employ elements for holding the media having a direct contact with the printed surface, which may cause ink smearing and other adverse affects on print appearance.
For instance, starwheels are employed in a number of apparatus for outputting printed media and may damage the printout with starwheel marks. Another drawback is the need to employ a mechanism or a structure to hold the starwheels themselves.
Conventionally, sheet holddown devices such as electrostatic or suction devices are employed only to reduce the effects of paper curl and cockle on dot placement during printing. In vacuum holddown devices, sheet flatness is maintained by providing suction between a support plate and the back surface of a sheet to be handled.
Cockle effect is the reluctance of the paper to bend smoothly. Instead it bends locally in a sharp fashion, creating permanent wrinkles.
Although conventional vacuum holddown devices are fairly effective in maintaining sheet flatness during printing, they have drawbacks. One drawback is the complexity of maintaining the same holddown force along the entire width of the medium while printing, i.e. in the direction of the printheads motion. This is due to the losses of air that the conventional devices allow, causing the medium to be subject to different forces, i.e. forcing the medium to rotate while it is advanced in the direction of the media motion.
Another drawback is that on one hand the maximum holddown force on a sheet is limited because of the necessity to maintain low frictional loads on transport devices which index the sheets. In conventional inkjet printers, such limitations can cause pen-to-sheet spacing distances to vary from swath to swath. Consequently, the holddown pressure at a localised area being printed may be insufficient to flatten cockles and other paper irregularities. On the other hand the vacuum required to eliminate cockle wrinkles in a printout would be so high that is normally unfeasible; in fact, high vacuum may suck the ink right through the paper and at the same time generate a lot of noise.
Applicant has then experimented that the employment of a vacuum holddown output unit may help media to be outputted without damaging the print appearance.
SUMMARY OF THE INVENTION
The present invention seeks to provide an improved hardcopy apparatus and method of outputted a printed medium in the hardcopy apparatus.
According to an aspect of the present invention, there is provided a hardcopy apparatus which comprises a main roller and an outputting mechanism for moving a medium outside of the hardcopy apparatus, said outputting mechanism comprises a vacuum holddown output unit for holding at least a portion of media down onto a surface of the outputting mechanism.
In this way the media is not held by any elements having a direct contact with the printed surface, which may cause ink smearing and other adverse affects on print appearance.
Preferably, said holddown unit comprises a vacuum source, connected to atmosphere through a plurality of first apertures formed into the surface, and a vacuum channel to generate a negative pressure capable of holding down at least a portion of media onto the surface.
In a preferred embodiment, said holddown unit further comprises advancing means capable, in co-operation with the generated negative pressure, to engage the back side of a medium and transfer said medium out of the hardcopy apparatus, and said advancing means comprise one or more wheels.
This avoids the use of starwheels in the apparatus, thus solving the problems of damaging the printout with starwheel marks and of employing a mechanism or a structure to hold the starwheels themselves.
In a preferred arrangement, said one or more wheels are rotating clockwise or counter-clockwise in order to output the medium from the apparatus.
Advantageously, the apparatus further comprises holding means for holding still a printed media for a predetermined dry time, and collecting means for collecting the printed media when released by the holding means, after the dry time, if any.
Viewing another aspect of the present invention, there is also provided method of outputting a printed medium from a hardcopy apparatus including a vacuum source, a main driving roller and a secondary roller, comprising the steps of: advancing the medium up to contact said secondary roller; generating a negative pressure, by means of the vacuum source, capable of engaging the back of the medium with the surface of the secondary roller; by rotating the main roller and the secondary roller, disengaging the medium from the main roller; and by rotating the secondary roller, advancing the medium towards the outside of the apparatus.
Preferably, the step of disengaging the medium from the main roller, comprises the step of cutting the medium.
In a preferred embodiment, the method further comprises the step of, stopping the rotation of the secondary roller (455) for a predetermined dry time. Typically, the method comprises the step of switching off the vacuum source, in order to collect the printout into collecting means.
Those operations are achieved in a particularly simple environment, where the same elements are operated in a different way in order to perform different scopes.
The present invention will be described further, by way of example only, with reference to an embodiment thereof as illustrated in the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of an inkjet printer incorporating the features of the present invention;
FIG. 2
is a more detailed diagram of a holddown system within the printer of
FIG. 1
;
FIG. 3
depicts a portion of the holddown system of
FIG. 2
;
FIG. 4
is a section of the main hardware components of the holddown system within the printer of
FIG. 1
;
FIG. 5
depicts a test curve of nominal values of the pressure applied to a medium vs. air flow provided by a vacuum device, employed in the holddown system of the preceding figures, in the rated voltage of 24 V.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to
FIG. 1
, a printer
110
includes a housing
112
mounted on a stand
114
. The housing has left and right drive mechanism enclosures
116
and
118
. A control panel
120
is mounted on the right enclosure
118
. A carriage assembly
100
illustrated in phantom under a cover
122
, is adapted for reciprocal motion along a carriage bar
124
, also shown in phantom. The carriage assembly
100
comprises four inkjet printheads
102
,
104
,
106
,
108
that store ink of different colours, e.g. black, magenta, cyan and yellow ink respectively, and an optical sensor
105
. As the carriage assembly
100
translates relative to the medium
130
along the X and Y axis, selected nozzles of the printheads
102
,
104
,
106
,
108
are activated and ink is applied to the medium
130
. The colours from the three colour printheads are mixed to obtain any other particular colour. The position of the carriage assembly
100
in a horizontal or carriage scan axis (Y) is determined by a carriage positioning mechanism with respect to an encoder strip. (not shown). A print medium
130
such as paper is positioned along a vertical or media axis by a media axis mechanism (not shown). As used herein, the media axis is called the X axis denoted as
101
, and the scan axis is called the Y axis denoted as
103
.
Referring now to
FIG. 2
, an holddown system is globally referenced as
200
. Such a holddown system
200
is located between the left and right drive mechanism enclosures
116
and
118
. The width of the holddown system along the Y axis is at least equal to the maximum allowable width of the media. In this example it should allow the employment of medium having width up to 36″, i.e. 914 mm. A more detailed description of the various components of the holddown system
200
will be made further with reference to FIG.
3
. The inkjet printheads
102
,
104
,
106
,
108
, are held rigidly in the movable carriage
100
so that the printhead nozzles are above the surface of a portion of the medium
130
which lays substantially flat on a flat stationary support platen
400
of said holddown system
200
.
With reference to
FIG. 3
, the flat platen
400
is shown in more details, and is located in a front position of the printer
110
and co-operate with a main driving roller
300
, in the following identified also as the main roller, located in a rear position, and a plurality of pinch wheels
310
, in this example 12 pinch wheels
310
are employed, which are controlled to periodically index or convey the medium across the surface of the platen
400
. The force between each pinch wheels
310
and the main roller
300
is comprised between 3.33 N and 5 N, preferably 4.15 N.
This pinch wheel distribution and force helps to drive the medium
130
straight with irrelevant lateral slippage, to share the medium
130
expansion on all its width. In fact has been observed that printers with low forces, e.g. about 1 N, allow media expansion accumulates in a particular place and this may cause a wrinkle to get so big to create a crash of the printhead.
The main roller
300
is provided with a conventional surface having a plurality of circumferencial recesses
305
housing a corresponding plurality of protrusions
405
of the platen
400
extending towards the rear of the printer
110
. This combination of features allows the medium
130
to reliably move from the main roller
300
to the platen
400
and vice versa. In fact the gap between the roller
300
and the platen
400
may allow an edge of the medium to engage the back of the platen itself causing a paper jam.
The printer
110
comprises, a vacuum source, in this case a fan not shown in the drawings, connected to the atmosphere through a plurality of holes, or apertures,
330
,
350
and a vacuum channel
380
; such vacuum source generates an air flow by sucking air from the atmosphere.
Due to the pressure differential between atmosphere pressure on the surface of the medium
130
and the vacuum applied through the vacuum channel
380
and the holes
330
,
350
to the back of the medium, the portion of the medium
130
close to the holes
330
,
350
is suckingly adhered to the platen
400
.
In order to reduce the losses of air from the vacuum channel
380
, the holes
330
,
350
are distributed at a certain distance from the main roller. According to this embodiment a plurality of first holes
330
lays in a line at a distance comprised between 10 mm and 30 mm, preferably 19 mm and a plurality of secondary holes
350
, distributed preferably in line.
Furthermore, the platen
400
is provided, according to this preferred example, with a plurality of substantially linear grooves having one end closer to and the opposed end further from the main roller
300
. Such grooves are linked together to form a continues slot
320
, which crosses substantially the whole width of the platen
400
, where such a continuous slot
320
is arranged to have a waved shape.
The plurality of first holes, or slot holes
330
, having a diameter comprises between 1.5 mm and 3.5 mm, preferably about 2.5 mm, are then distributed inside the waved slot
320
, and in this embodiment are preferably located in the further part of the slot
320
with respect to the main roller
300
.
It is important to note that since the main roller
300
is not included within the vacuum channel
380
, the vacuum can be only directly generated at a certain distance from the main roller
300
itself. However, if the slot
320
is included in the unit, when the vacuum source is activated and in presence of a medium on the platen
400
, the vacuum can be expanded along all the slot extending the vacuum closer to the main roller
300
.
In this application extending the vacuum means that the vacuum generated at one aperture, which is normally supplied to an area of the back of medium, is now supplied to an area of the back of the medium which is at least 10% bigger, preferably bigger than 500%.
This helps in more uniformly apply the vacuum to the back of the medium, reducing the risk of having peak of vacuum that may crease the medium. Furthermore, thanks to the slot
320
there is no need to conventionally include the main roller
300
into the vacuum channel
380
and this means that: a) the air losses are minimised, since in conventional systems, having the main roller included in the vacuum channel, most of the air is lost around the main roller itself; b) the air flow is forwarded towards the main roller
300
, meaning that a print zone
450
can be defined closer to the main roller
300
; and c) the dimensions of the vacuum channel can be better controlled, giving more design freedom for designing the holddown system.
Size of the vacuum channel is a further parameter relevant to apply the proper vacuum to the back of the medium. Experiments run by the Applicant have shown that the surface of squared section of the vacuum channel
380
, as depicted in
FIG. 3
, is preferably bigger than the sum of the surface of all the apertures
330
,
350
distributed within the platen
400
. More preferably the surface of the squared section is as big as twice, or more, the sum of the surface of all the apertures
330
,
340
.
According to the above, it is possible to print closer to the edges of a cut medium. In fact the medium can still be indexed by the main roller
300
and the pinch rollers
310
even when we are printing close to the very end of the medium itself.
Applicant's extended tests have revealed that a width too wide of the slot can reduce the capability of maintaining the medium substantially flat while printing, so affecting the printing quality. On the contrary, a width too narrow and/or an insufficient depth may affect the air flow direction, i.e. the vacuum force is not extended close enough to the main roller
300
.
Furthermore, high vacuum may crease the paper especially if the grooves of the slot
320
are wide and run parallel to the paper advance direction. Therefore is advisable to run the grooves at about 45° respect to the media axis X and optimise the slot width to minimise creases in the paper and to evenly distribute the vacuum. In addition, if the groove is parallel to the advance direction, it may make the ink to migrate and create localised dark areas.
This means that it is not necessary that the plurality of grooves are linked together in order to form a continuous slot for achieving the above advantage.
Accordingly, the slot
320
has a depth deeper than 0.5 mm, preferably 1 mm, and a width comprises between 3 mm and 8 mm, preferably 5 mm.
However, the continuous shape of the waved slot
320
helps the holddown system
200
to evenly distribute the vacuum along the print zone
450
. In fact, an interrupted sequence of grooves may create areas, having a reduced vacuum, which cross the complete print zone
450
, in the media axis direction X. This may force the ink applied in those areas to migrate and create localised dark or clear portions in the printout.
Further from the waved slot
320
, along the media axis (X), the platen
400
is provided with a plurality of secondary recesses
360
, distributed in one line along the scan axis (Y). In this example each recess
360
is composed by two parts, a first one substantially squared and a second one substantially triangular, where the triangular part lays on a plane which deeper than the plane on which the squared part lays.
Furthermore, each squared part is provided with a secondary hole
350
, having a diameter comprises between 1.5 and 2.5 mm, preferably 2.0. Such sequence of secondary recesses
360
is combined with a sequence of overdrive wheels
340
, forming a secondary roller
345
, such that a group of 3 consecutive secondary recesses
360
is disposed between two consecutive wheels
340
. Such a secondary roller is housed in the vacuum channel
380
.
Thus, this holddown system
200
comprises 12 overdrive wheels
340
equally separated along the scan axis (Y) to supply equal traction to each part of the medium.
In this description an overdrive wheel may mean a single wheel as well as a plurality of wheels in strict contact one to another, in order to build a wheel having a larger width.
A secondary recess
360
is distanced by each adjacent element, both a further secondary recess
360
or a wheel
340
, by a rib
370
. The ribs are employed to reduce the risk of generating cockle wrinkles which may extend towards the print zone
450
.
Accordingly, two consecutive ribs
370
, having a preferably height of 1 mm, are distanced one to another by a distance comprised between 15 mm and 25 mm, preferably about 20 mm if the two ribs
370
are separated by a secondary recess
360
.
The plurality of secondary holes
350
provides the vacuum channel
380
with further apertures for the air flow generated by the vacuum source.
Since the air flow between the top of the platen
400
and the back of the medium
130
may generate noise in correspondence of the secondary holes
350
, the particular shape of the recesses
360
helps to provide the air flow with a smooth transition, reducing the resulting noise.
As for the slot holes
330
, the vacuum generated in correspondence of the secondary holes
350
is extended, in order to apply a negative pressure to most of the medium
130
laying on the platen
400
. The vacuum is extended particularly due to the presence of the overdrive wheels
340
, and the ribs
370
, which create a larger empty space between the medium
130
and the platen
400
.
Furthermore, the design of this part of the holddown system helps the printer to reduce the cockle effect on the printout.
Tensioning the paper in the feeding direction intuitively does not help, because cockle wrinkles mainly extend in the feeding direction as well. Anyway, overdrive forces can reduce the height reached by the cockle wrinkles by as much as a half. In addition, it was noted how the paper works in compression, some very thin papers may even buckle and create loops between the main roller
300
and the print zone.
This means that the presence of a secondary roller
345
, having the function of tensioning the paper during the printing operation, may help in controlling the occurrence of the cockle wrinkles in the printout.
However, it should be kept in mind that such a secondary roller
345
provide the printer
110
with more capabilities, which will be described further.
In this portion of the platen
400
, vacuum is furnished through the plurality of holes
350
and the gap between each overdrive wheel
340
and its surrounding portion of the platen
400
.
Vacuum is used to provide the force between medium and overdrive wheels
340
; the design has been done in such a way that it can provide the required force to the overdrive wheel
340
, preferably comprised between 0.6 N and 1 N, in this example 0.8 N per each wheel
340
, without employing starwheels. Elimination of starwheels is an important issue since it helps to avoid a) the risk of damaging the printout with starwheel marks, b) the need to employ a mechanism or a structure to hold the starwheels themselves.
In addition, according to this example, in order to transmit the proper traction force to the medium, the overdrive interference, i.e. the distance between the surface of the platen
400
and the top of the a overdrive roller
340
, is preferably maintained between 0.3 mm and 0.6 mm. Below 0.25 mm the traction falls quickly, towards zero traction at zero interference; if the interference is bigger than 0.65 mm, wrinkles created by the overdrive roller
340
can extend to the print zone
450
.
In
FIGS. 2 and 3
it is also shown a first reference sign
390
, according to this example, in the form of a phantom line, but any kind of suitable reference can be employed, e.g. a continuous or dotted line. This first reference
390
is traversing all the platen
400
from the right to the left side in the scan axis (Y) direction. Preferably the first reference
390
is tangent to the slot
320
, on the side closer to the main roller
300
, and it could be in colour and/or in under-relief. This feature is used preferably in combination with a second reference
392
, placed at one side end of the platen
400
. The second reference is traversing the platen
400
in the media axis (X) direction, preferably starting from the first reference
390
to the end of the platen
400
further from the main roller
300
.
Accordingly, the user is provided with two references for placing correctly the edges of a cut media sheet, or a media roll, onto the platen
400
in order to load and feed the sheet into the printer
110
. Particularly, the first reference
390
is providing the user with a reference which can fully match an edge of the sheet, so simplifying the loading operation.
In this embodiment a second reference is placed at one end of the platen
400
, which is conventionally located at the right end of the printer, respect to the user placing the sheet.
This combination of references enhances the easiness of the loading operation by the user, reducing the occurrence of inaccurate positioning of the medium, which may cause a paper jam, during the feeding or the printing phases.
Referring now to
FIG. 4
, it is shown the main roller
300
and one of the pinch wheels
310
co-operating with one protrusion
405
of the platen
400
holding the medium
130
. One of the overdrive wheels
340
, tensioning the medium
130
in the print zone
450
, is also shown. From
FIG. 4
it is better depicted that the vacuum channel
380
does not extend underneath the complete print zone
450
, particularly the vacuum channel
380
is partially overlapped by a portion of the print zone
450
which is less than 90% of the complete print zone
450
, preferably less than 50%, and more preferably about 30-35%.
Referring now to
FIG. 5
, a diagram showing nominal values supplied by the vacuum source, a fan, employed in this example. Those values have been measured running the fan at its full power of 24 V. The pressure unit on the Y axis is Pascal and air flow unit on the X axis is m
3
/min.
Vacuum required to eliminate cockle wrinkles in a printer would be so high that is normally unfeasible; in fact, high vacuum may suck the ink right through the paper and at the same time generate a lot of noise. The vacuum level has been preferably set between 380 Pa and 440 Pa, which can be achieved by a small fan, producing acceptable level of noise, i.e. about 65 dBA.
Several test run by the Applicant have verified that this level is enough for rigid roll paper, like high glossy photo roll, in order to flatten the curling during printing. In addition, it has been verified with many print modes that this level of vacuum is unlikely to suck the ink through the paper.
Five operational levels of vacuum have been defined for the following activities:
|
Normal CAD printing
21 V
|
Thick paper and high density prints
24 V
|
Loading and cutting media
22 V
|
Holddown during cut sheet loading
16 V
|
Managing thin Japanese rice paper, always
14 V
|
|
According to FIG.
5
and to the tests run by the Applicant, one characteristic of the fan considered particularly valuable has been the capability of providing a pressure of 300 Pa, when the air flow is at about 0.5 m
3
/min.
Now reference is made to
FIGS. 1
,
2
,
3
and
4
in order to describe how a medium can be loaded into, printed with and outputted from the printer
110
.
LOADING OPERATION
A loading operation can be activated in a plurality of different ways, e.g. by a user selection of the operation from the front panel
120
of the printer
110
, or more easily, as in this embodiment, by opening the cover
122
.
Once that the loading operation is activated the vacuum source is powered on, at 16 V, in order to help the loading operation.
In the following an example on how to load a cut sheet of media will be described. However a skilled in the art may appreciate that, similarly, a roll of media may also be load.
In order to load a cut sheet of media into the printer, a user should place the top edge of the medium
130
in correspondence of the first reference
390
, and the top portion of the right edge of the same medium
130
in correspondence of the second reference. During all this phase the vacuum on is helping the user in holding the medium
130
adherent to the platen
400
, so that small adjustments in the position of the medium
130
can be done using only one hand. Accordingly, the risk of inadvertently damaging the medium
130
(e.g. due to fingerprints or to the fall of the medium
130
on the ground) are minimised.
Once that the loading step has been completed, the medium
130
is fed into the printer for the printing phase. The feeding step may be activated in several ways. For instance, it is automatically activated after that sensors have sensed the proper positioning of the medium
130
, or by user selection of the feeding operation from the front panel
118
, or, as in this embodiment, by closing the cover
122
.
Once that feeding step is activated, the overdrive wheels
340
start to move clockwise in order to advance the medium
130
towards the main roller
300
, until the medium
130
itself is engaged between the main roller and the pinch wheels
310
. The vacuum is maintained on to transmit the traction force from the overdrive wheels
340
to the medium
130
.
As soon as main roller is fed with the medium
130
, conventional steps are carried on in order to remove the medium
130
from the platen
400
and to convey the medium
130
, into a feeding guide for a subsequent printing phase. Finally, the vacuum source is switched off.
PRINTING OPERATION
When a printing operation is activated, the main roller
300
in co-operation with the pinch rollers
310
and other conventional elements of the printer
110
, starts to convey the medium, from the feeding guide, across the print zone defined onto the platen
400
. Contemporarily, the vacuum source is switched on, at a power according to the kind of media employed and/or to the kind of plot which will be printed. Thus, the vacuum is keeping the medium
130
substantially flat onto the print zone
450
defined on the platen
400
to allow a quality printing. Preferably, before starting printing, the main roller is advancing the medium towards the overdrive wheels
340
, to have the medium engaged by them. In fact, as already explained, the medium should be tensioned in the media direction X to keep the cockle wrinkles under control. Alternatively, the printing may start even if the overdrive wheels
340
are not engaged yet with the medium.
Once that the medium
130
is also engaged by the overdrive wheels the advance of the medium in the print zone along the media axis direction X is performed by a pushing force provided by the main roller
300
, moving counter-clockwise, and the pinch wheels
310
, moving clockwise, and by a pulling force provided by the overdrive wheels
340
, moving counter-clockwise too.
Conventional printing steps allow the carriage assembly
100
to move the printheads
102
,
104
,
106
, and
108
, relative to the medium
130
along the scan axis Y, in order to apply ink to the medium
130
, in one or more passes, and so reproducing the desired image.
OUTPUTTING OPERATION
An outputting operation may be activated for instance a) automatically when a printing operation has been completed or aborted, or b ) manually by a user request.
When the operation is activated the printer verifies if the medium
130
to be outputted is a cut sheet or a roll. If the medium
130
is a roll a cutting step is performed. This means that the medium
130
is advanced in the cutting position and the vacuum source is powered on, at 22 V, to hold the medium substantially flat and minimise the movement of the same while a blade, not shown, is traversing the medium
130
along the scan axis Y to cut the medium.
If the medium
130
is a cut sheet or after that the roll has been cut, the medium is advanced in the media axis direction X towards the front of the printer
110
, i.e. further from the main roller
300
.
The advancement of the medium is performed by the counter-clockwise movement of the overdrive wheels
340
, frictionally engaging a portion of the back of the medium
130
, due to the negative pressure generated by the vacuum source applied to the medium
130
. If a cut sheet of media
130
is still engaged with the main roller
300
and the pinch wheels
310
, those elements are also co-operating to advance the medium. In case that the printout printed onto the medium
130
requires an additional dry time, the overdrive wheels movement is stopped when most of the printout is advanced out of the printer, e.g. as shown in FIG.
1
. The vacuum source is kept on for the required time to dry the medium, so holding only an end region of the medium
130
, preferably having length equal to the width of the medium
130
and about 50 mm in the media axis direction X.
Finally, the vacuum is switched off to drop the medium
130
, e.g. into a conventional collecting bin, not shown.
The skilled in the art may appreciate that, in accordance to this preferred embodiment, the same holddown system, e.g. having one platen and one vacuum source, may be capable of being employed to perform a plurality different operations, such as loading and feeding operation, printing operation and outputting operation. However, each of these operations may be performed also using independent holddown systems, i.e. independent holddown surfaces and/or independent vacuum source. Furthermore, the skilled in the art is now aware that only some of those operations may be performed by means of a vacuum holddown system while the remaining ones may be performed employing conventional systems.
Claims
- 1. A hardcopy apparatus comprising a main roller and an outputting mechanism for moving a medium outside the hardcopy apparatus, said outputting mechanism comprising a vacuum holddown output unit, for holding at least a portion of media down onto a surface of the outputting mechanism, the media being held down by at least such unit.
- 2. The hardcopy apparatus as claimed in claim 1, wherein said holddown unit comprises a vacuum source, connected to atmosphere through a plurality of first apertures formed into the surface, and a vacuum channel to generate a negative pressure capable of holding down at least a portion of media onto the surface.
- 3. The hardcopy apparatus as claimed in claim 2, wherein said holddown unit further comprises advancing means capable, in co-operation with the generated negative pressure, to engage the unprinted side of a medium and transfer said medium out of the hardcopy apparatus.
- 4. The hardcopy apparatus as claimed in claim 3, wherein said advancing means comprise one or more wheels.
- 5. The hardcopy apparatus as claimed in claim 4, wherein said one or more wheels are rotating clockwise or counter-clockwise in order to output the medium from the apparatus.
- 6. The hardcopy apparatus as claimed in claim 5, further comprises holding means for holding still a printed media for a predetermined dry time.
- 7. The hardcopy apparatus as claimed in claim 6, further comprising collecting means for collecting the printed media when released by the holding means, after the dry time if any.
- 8. A method of outputting a medium from a hardcopy apparatus including a vacuum source, a main driving roller and a secondary roller, comprising the following steps:advancing the medium up to contact said secondary roller; generating a negative pressure, by means of the vacuum source, capable of engaging the unprinted side of the medium with the surface of the secondary roller; by rotating the main roller and the secondary roller, disengaging the medium from the main roller; and by rotating the secondary roller, advancing the medium towards the outside of the apparatus.
- 9. The method as claimed in claim 8, wherein the step of disengaging the medium from the main roller, comprises the step of cutting the medium.
- 10. The method as claimed in claim 8, further comprises the step of, stopping the rotation of the secondary roller for a predetermined dry time.
- 11. The method as claimed in claim 8, further comprising the step of switching off the vacuum source, in order to collect the printout into collecting means.
- 12. A hardcopy apparatus comprising a main roller and an outputting mechanism for moving a medium outside the hardcopy apparatus, said outputting mechanism comprising a vacuum holddown output unit for holding at least a portion of media down onto a surface of the outputting mechanism such that said media is not held by any elements having a direct contact with a printed portion of said media.
- 13. The hardcopy apparatus as claimed in claim 12, wherein said holddown unit comprises a vacuum source, connected to atmosphere through a plurality of first apertures formed into the surface, and a vacuum channel to generate a negative pressure capable of holding down at least a portion of media onto the surface.
- 14. The hardcopy apparatus as claimed in claim 13, wherein said holddown unit further comprises advancing means capable, in co-operation with the generated negative pressure, to engage the unprinted side of a medium and transfer said medium out of the hardcopy apparatus.
- 15. The hardcopy apparatus as claimed in claim 14, wherein said advancing means comprise one or more wheels.
- 16. The hardcopy apparatus as claimed in claim 15, wherein said one or more wheels are rotating clockwise or counter-clockwise in order to output the medium from the apparatus.
- 17. The hardcopy apparatus as claimed in claim 16, further comprises holding means for holding still a printed media for a predetermined dry time.
- 18. The hardcopy apparatus as claimed in claim 17, further comprising collecting means for collecting the printed media when released by the holding means, after the dry time if any.
Priority Claims (1)
Number |
Date |
Country |
Kind |
98120703 |
Oct 1998 |
EP |
|
US Referenced Citations (5)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 379 306 A2 |
Jul 1990 |
EP |
0 379 306 A3 |
Jul 1990 |
EP |