MEDIA GUIDING SYSTEM USING BERNOULLI FORCE ROLLER
A media-guiding system includes a media-guiding roller having a roller axis and an exterior surface having one or more grooves formed around the exterior surface. A media travels along a transport path past the media-guiding roller with a first side of the media facing the exterior surface of the web-guiding roller. An air source provides an air flow into one or more of the grooves, the air flow being directed between the first side of the media and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the media-guiding roller and providing an increased traction between the media and the media-guiding roller.
Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 14/016,427, entitled “Positive pressure web wrinkle reduction system,” by Kasiske Jr., et al.; to commonly assigned, co-pending U.S. patent application Ser. No. ______ (Docket K001684), entitled “Air shoe with roller providing lateral constraint,” by Cornell et al.; to commonly assigned, co-pending U.S. patent application Ser. No. ______ (Docket K001724), entitled “Air shoe with integrated roller,” by Cornell et al.; to commonly assigned, co-pending U.S. patent application Ser. No. ______ (Docket K001717), entitled “Wrinkle reduction system using Bernoulli force rollers,” by Muir et al.; and to commonly assigned, co-pending U.S. patent application Ser. No. ______ (Docket K001723), entitled “Media diverter system using Bernoulli force rollers,” by Muir et al., each of which is incorporated herein by reference.
FIELD OF THE INVENTIONThis invention pertains to the field of media transport and more particularly to an apparatus for guiding a web of receiver media using rollers that impart a Bernoulli force to the receiver media.
BACKGROUND OF THE INVENTIONIn a digitally controlled inkjet printing system, a receiver media (also referred to as a print medium) is conveyed past a series of components. The receiver media can be a cut sheet of receiver media or a continuous web of receiver media. A web or cut sheet transport system physically moves the receiver media through the printing system. As the receiver media moves through the printing system, liquid (e.g., ink) is applied to the receiver media by one or more printheads through a process commonly referred to as jetting of the liquid. The jetting of liquid onto the receiver media introduces significant moisture content to the receiver media, particularly when the system is used to print multiple colors on a receiver media. Due to the added moisture content, an absorbent receiver media expands and contracts in a non-isotropic manner, often with significant hysteresis. The continual change of dimensional characteristics of the receiver media can adversely affect image quality. Although drying is used to remove moisture from the receiver media, drying can also cause changes in the dimensional characteristics of the receiver media that can also adversely affect image quality.
U.S. Pat. No. 3,405,855 to Daly et al., entitled “Paper guide and drive roll assemblies,” discloses a web guiding apparatus having peripheral venting grooves to vent air carried by the underside of the traveling web.
U.S. Pat. No. 4,322,026 to Young, Jr., entitled “Method and apparatus for controlling a moving web,” discloses a method for smoothing and guiding a web in which the web is moved in an upward direction past pressurized fluid discharge manifolds on either side of the web. The manifolds direct continuous streams of pressurized fluid, such as air, outwardly toward the side edges of the web to smooth wrinkles in the web. Additional manifolds are used to intermittently direct streams of fluid to laterally move and guide the web.
U.S. Pat. No. 4,542,842 to Reba, entitled “Pneumatic conveying method for flexible webs,” discloses a method for conveying a web using inner and outer pairs of side jet nozzles employing the Coanda effect to propel the web while preventing undue distortion.
U.S. Pat. No. 5,979,731 to Long et al., entitled “Method and apparatus for preventing creases in thin webs,” discloses an apparatus for removing longitudinal wrinkles from a thin moving web of media. The media is wrapped around a perforated cylindrical air bar disposed in proximity to a contact roller.
U.S. Pat. No. 6,427,941 to Hikita, entitled “Web transporting method and apparatus,” discloses a web transporting apparatus that transports a web by floating the web on air jetted from holes formed in a roller while the edges of the web are supported by edge rollers.
There remains a need for a means to prevent the formation of receiver media wrinkles as a receiver media contacts web-guiding structures in a digital printing system.
SUMMARY OF THE INVENTIONThe present invention represents a media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:
a media-guiding roller having a roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the media travels along the transport path past the media-guiding roller with the first side of the media facing the exterior surface of the web-guiding roller; and
an air source for providing an air flow into one or more of the grooves, the air flow being directed between the first side of the media and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the media-guiding roller and providing an increased traction between the media and the media-guiding roller.
This invention has the advantage that the media can be controlled by providing adequate fraction even when there is minimal wrap of the media around the media-guiding roller.
It has the additional advantage that in various embodiments the media-guiding roller can be used to steer the media, or to provide a stretching force to prevent wrinkles from forming.
It has the further advantage that it can reduce fluttering in receiver media webs that can result from insufficient traction between media-guiding rollers and the receiver media web in prior art systems.
The present description will be directed in particular to elements forming part of, or cooperating more directly with, an apparatus in accordance with the present invention. It is to be understood that elements not specifically shown, labeled, or described can take various forms well known to those skilled in the art. In the following description and drawings, identical reference numerals have been used, where possible, to designate identical elements. It is to be understood that elements and components can be referred to in singular or plural form, as appropriate, without limiting the scope of the invention.
The invention is inclusive of combinations of the embodiments described herein. References to “a particular embodiment” and the like refer to features that are present in at least one embodiment of the invention. Separate references to “an embodiment” or “particular embodiments” or the like do not necessarily refer to the same embodiment or embodiments; however, such embodiments are not mutually exclusive, unless so indicated or as are readily apparent to one of skill in the art. It should be noted that, unless otherwise explicitly noted or required by context, the word “or” is used in this disclosure in a non-exclusive sense.
The example embodiments of the present invention are illustrated schematically and may not be to scale for the sake of clarity. One of ordinary skill in the art will be able to readily determine the specific size and interconnections of the elements of the example embodiments of the present invention.
As described herein, the exemplary embodiments of the present invention provide receiver media guiding components useful for guiding the receiver media in inkjet printing systems. However, many other applications are emerging which use inkjet printheads to emit liquids (other than inks) that need to be finely metered and deposited with high spatial precision. Such liquids include inks, both water based and solvent based, that include one or more dyes or pigments. These liquids also include various substrate coatings and treatments, various medicinal materials, and functional materials useful for forming, for example, various circuitry components or structural components. As such, as described herein, the terms “liquid” and “ink” refer to any material that is ejected by the printhead or printhead components described below.
Inkjet printing is commonly used for printing on paper, however, there are numerous other materials in which inkjet is appropriate. For example, vinyl sheets, plastic sheets, textiles, paperboard and corrugated cardboard can comprise the receiver media. Additionally, although the term inkjet is often used to describe the printing process, the term jetting is also appropriate wherever ink or other liquids is applied in a consistent, metered fashion, particularly if the desired result is a thin layer or coating.
Inkjet printing is a non-contact application of an ink to a receiver media. Typically, one of two types of ink jetting mechanisms is used, and is categorized by technology as either drop-on-demand inkjet printing or continuous inkjet printing.
Drop-on-demand inkjet printing provides ink drops that impact upon a recording surface using a pressurization actuator, for example, a thermal, piezoelectric or electrostatic actuator. One commonly practiced drop-on-demand inkjet type uses thermal energy to eject ink drops from a nozzle. A heater, located at or near the nozzle, heats the ink sufficiently to form a vapor bubble that creates enough internal pressure to eject an ink drop. This form of inkjet is commonly termed “thermal inkjet.” A second commonly practiced drop-on-demand inkjet type uses piezoelectric actuators to change the volume of an ink chamber to eject an ink drop.
The second technology commonly referred to as “continuous” inkjet printing, uses a pressurized ink source to produce a continuous liquid jet stream of ink by forcing ink, under pressure, through a nozzle. The stream of ink is perturbed using a drop forming mechanism such that the liquid jet breaks up into drops of ink in a predictable manner. One continuous inkjet printing type uses thermal stimulation of the liquid jet with a heater to form drops that eventually become printing drops and non-printing drops. Printing occurs by selectively deflecting either the printing drops or the non-printing drops and catching the non-printing drops using catchers. Various approaches for selectively deflecting drops have been developed including electrostatic deflection, air deflection, and thermal deflection.
There are typically two types of receiver media used with inkjet printing systems. The first type of receiver media is in the form of a continuous web, while the second type of receiver media is in the form of cut sheets. The continuous web of receiver media refers to a continuous strip of receiver media, generally originating from a source roll. The continuous web of receiver media is moved relative to the inkjet printing system components using a web transport system, which typically include drive rollers, web guide rollers, and web tension sensors. Cut sheets refer to individual sheets of receiver media that are moved relative to the inkjet printing system components via rollers and drive wheels or via a conveyor belt system that is routed through the inkjet printing system.
The invention described herein is applicable to both drop-on-demand and continuous inkjet printing technologies that print on continuous webs of receiver media. As such, the term “printhead” as used herein is intended to be generic and not specific to either technology. Additionally, the invention described herein is also applicable to other types of printing systems, such as offset printing and electrophotographic printing, that print on continuous webs of receiver media.
The terms “upstream” and “downstream” are terms of art referring to relative positions along the transport path of the receiver media; points on the receiver media move along the transport path from upstream to downstream.
Referring to
Below each printhead 20a, 20b, 20c, 20d is a media guide assembly including print line rollers 31 and 32 that guide the continuous web of receiver media 10 past a first print line 21 and a second print line 22 as the receiver media 10 is advanced along a media path in the in-track direction 4. Below each dryer 40 is at least one dryer roller 41 for controlling the position of the web of receiver media 10 near the dryers 40.
Receiver media 10 originates from a source roll 11 of unprinted receiver media 10, and printed receiver media 10 is wound onto a take-up roll 12. Other details of the printing module 50 and the printing system 100 are not shown in
Referring to
If there is insufficient wrap of the web of receiver media 10 around the media-guiding roller 70 or insufficient tension in the web of receiver media 10, the entrained airflow 76 can cause the receiver media 10 to float free of the media-guiding roller 70 on a thin air cushion 74 of the entrained air, and can induce fluttering of the receiver media 10, a vibration of the receiver media 10 perpendicular to the in-track direction 4 and the cross-track direction 7 (
To avoid these stability problems, U.S. Pat. No. 3,405,855 to Daly Jr. et al., entitled “Paper guide and drive roll assemblies,” introduced grooves into the media contact surface of the media-guiding roller 70. The air entrained by the moving web of receiver media 10 can flow into the grooves of the roller, allowing the web of receiver media 10 to contact the contact surface of the media-guiding roller 70 in the area between the grooves. There are times when design constraints of the printing system are such that little or no wrap is possible around a media-guiding roller 70. In such printing systems, it has been found that even the use of a grooved guiding roller is insufficient to ensure traction between the receiver media 10 and the grooved surface of the media-guiding roller 70. Such printing systems are therefore susceptible to cross-track wander of the receiver media 10, and also to media flutter. The present invention overcomes the limitations of such prior art web-guiding systems.
The one or more grooves 84 serve as air channels for the airflow 90. As the airflow 90 passes through a groove 84 between the first side 15 of receiver media 10 and the exterior surface 83 of the media-guiding roller 80, the contour of the bottom of the groove 84 forms a constriction 92 to the airflow 90. The well-known “continuity principle” of fluid dynamics requires the airflow 90 to accelerate as it passes through the constriction 92. According to the well-known Bernoulli's Principle, the increased velocity of the airflow 90 at the constriction 92 is accompanied by the development of a low pressure zone between the high point of the groove 84 and the receiver media 10. A pressure differential is therefore developed from the second side 16 to the first side 15 of the receiver media 10, resulting in a Bernoulli force F on the receiver media 10 which draws the receiver media 10 down toward, or into contact with, the exterior surface 83 of the media-guiding roller 80. As a result, the media-guiding roller 80 is able to provide a lateral constraint on the web of receiver media 10, preventing the receiver media 10 from drifting in the cross-track direction 7 (
An advantage provided by the media-guiding system 78 of the present invention is that all of the system components are located on one side of the receiver media 10. This is useful in many systems where there are tight geometric constraints.
In some embodiments, the media-guiding roller 80 is a passive roller having no drive mechanism so that it rotates freely in response to traction with the receiver media 10. In other embodiments, a drive mechanism (not shown) can be used to rotate the media-guiding roller 80 around its roller axis 81. In such configurations, the media-guiding roller 80 can be used to impart a force on the receiver media 10 to move it along the transport path in the in-track direction 4. Driven media-guiding rollers 80 are of particular value when the receiver media 10 is in the form of cut sheets, as the intermittent passage of individual sheets past the media-guiding roller 80 may be insufficient to maintain the rotation of the media-guiding roller.
Commonly-assigned U.S. patent application Ser. No. 14/016,427, entitled: “Positive pressure web wrinkle reduction system,” by Kasiske Jr., et al, describes a web-guiding system where an air source is used to direct an airflow through a pattern of recesses in a web-guiding structure. The described configurations prevent wrinkles from forming in the receiver media as it passes around the web-guiding structure by causing portions of the receiver media overlying the recesses to lift away from the web-guiding structure. In some of the embodiments described by Kasiske Jr., et al., the recesses are grooves similar to those described with respect to
In an exemplary embodiment, the media-guiding roller 80 has a radius of 2.5 inches, the grooves 84 have a groove width wg of 0.375 inches and a groove depth dg of 0.125 inches. The exit of the air source 86 is preferably sized such that the width of the opening is approximately the same as the groove width wg, and the height of the opening is somewhat larger than the groove depth dg of the grooves 84 to provide an airflow depth da that will be reduced as it passes through the constriction 92 in order to accelerate the airflow 90 and produce the Bernoulli force F. In the exemplary embodiment, the groove depth dg is smaller than the airflow depth da by about 20% (i.e., the airflow depth da entering the grooves 84 is about 0.150 inches). In other embodiments, other air flow depths da can be used to provide different amounts of constriction. For example, in some embodiments the groove depth dg can be smaller than the airflow depth da entering the grooves 84 by about 10-50%.
The magnitude of the Bernoulli force F will be related to magnitude of the airflow 90 provided into of the grooves 84, together with the amount of constriction 92 the airflow 90 experiences as it passes by the grooves 84. In an exemplary embodiment, it has been found that an acceptable Bernoulli force F to guide the receiver media 10 with the media-guiding roller 80 is obtained when the air source 86 provides an airflow 90 having a velocity of about 100-400 m/s, although different velocities can be used depending on the geometry of the grooves 84 and the requirements of the particular application.
The media-guiding system 78 can be used to provide a variety of media control process functions. For example, in some printing systems 110 (
When the actuator 94 tilts the media-guiding roller 80 so that the roller axis 81 is oriented in a non-orthogonal direction relative to the in-track direction 4 (i.e., in a direction that is not parallel to the cross-track direction 7), when the air source 86 is activated the traction between the media-guiding roller 80 and the receiver media 10 will steer the web of receiver media 10 in accordance with the tilt direction. In the configuration shown in
In the configurations shown in
The flute detection system 185 can use any method known in the art to detect the presence of any flutes (also known as wrinkles or ripples) in the receiver media 10. Preferably the flute detection system 185 detects the height and spacing of any detected flutes. In an exemplary embodiment, the flute detection system 185 uses laser triangulation to detect and characterize any ripples or flutes in the receiver media 10. In an alternate embodiment, the flute detection system 185 projects a grating pattern onto the receiver media 10 from one angle and the projected grating pattern on the receiver media 10 is viewed, typically with a digital camera, from a different angle; a procedure known as fringe projection or projection moiré interferometry. Any distortion in the surface of the receiver media 10 causes the viewed grating lines to be warped, enabling any flutes to be easily detected. In an another alternate embodiment, the receiver media 10 can be illuminated by a light source at a low incidence angle, and a digital imaging system can be used to capture an image of the receiver media 10. In this case, the sides of the flutes facing the light source will show up as lighter regions, while the sides of the flutes facing away from the light source will show up as darker regions.
Based on the detection of flutes (i.e., wrinkles), including the height and spacing of flutes, the controller 195 adjusts the rate of airflow 90 to control the degree of spreading of the receiver media 10 to keep the fluting below an acceptable level. For example, the rate of airflow 90 can be increased to a higher level when larger flutes are detected relative to when smaller flutes are detected.
In another embodiment (not shown), force sensors attached to the media-guiding rollers 180 measure the lateral force applied by the media-guiding rollers 180 on the receiver media 10. The controller 195 regulates the airflow 90 provided by air sources 86 such that the spreading force doesn't exceed the tensile strength of the receiver media 10. As the tensile force applied by the receiver media 10 on the media-guiding rollers 180 will be low until the receiver media 10 has been spread sufficiently to flatten the ripples and fluting of the receiver media 10, the output of the force sensors attached to the media-guiding rollers 180 can be analyzed to detect when a sufficient spreading force has been applied to the receiver media 10 to sufficiently flatten the flutes, and the airflow 90 can be controlled to maintain the desired level of spreading force.
In some embodiments, the two media-guiding rollers 180 in
In some embodiments, the tilt angle of the roller axes 81 of the media-guiding rollers 180 can also be controlled (e.g., using the actuator mechanism shown in
In an alternate embodiment, the two media-guiding rollers 180 in
In some embodiments, the tilt angle of the roller axes 81 of the media-guiding rollers 180 can also be controlled (e.g., using the actuator mechanism shown in
While the above embodiments of Bernoulli-force media-guiding rollers 80, 180 have been described with respect to printing systems 100, 110 configured to print on a continuous web of receiver media 10, it will be obvious to one skilled in the art that the disclosed Bernoulli-force media-guiding rollers can also be used in media-guiding systems for cut sheets of media. In some embodiments, the Bernoulli-force media-guiding rollers can be used in cut sheet media transports for operations such as cross-track steering and cross-track spreading of cut sheets, which are similar to the analogous operations which have been discussed above for web-fed media transports. In other embodiments, the Bernoulli-force media-guiding rollers of the present invention can also be used to alter the path taken by a sheet of media.
In
The embodiments of
When the media sheet 210 reaches a transfer position 240, it can be directed into either the left media path 230 or the right media path 235. To direct the media sheet 210 into the left media path 230, controller 295 leaves the air sources 86 in a deactivated state. The media sheet 210 will then continue in an undeviated direction and will move into the left media path 230. To divert the media sheet 210 into the right media path 235, the controller 295 activates the air sources 86 in the roller assemblies 260 when the media sheet 210 reaches the transfer position 240. As discussed above, directing the airflow 90 from the air sources 86 through the grooves 84 in the media-guiding rollers 180 causes the media sheet 210 to be drawn down into contact with the rotating media-guiding rollers 180 by a Bernoulli force. The resulting traction will cause the media sheet 210 to be moved by the media-guiding rollers 180 along a media diversion path 245 until it reaches a shifted position 250, which is laterally shifted relative to the input media path 205, at which time the air sources 86 are deactivated by the controller 295. The media sheet 210 can then proceed along the right media path 235 using any appropriate media drive mechanism (not shown).
The direction of the media diversion path 245 is determined by the orientation of the roller assemblies 260. Generally, the direction of the media diversion path 245 will be perpendicular to the direction of the roller axis 81, and parallel to the direction of the groove 84. In the illustrated embodiment, the media diversion path 245 is angled at approximately 30° relative to the in-track direction 4, however, this is not a requirement. In other embodiments, different directions can be used for the media diversion path 245 as long as the direction includes a lateral component. For example, in some embodiments, the roller assemblies 260 can be oriented such that the rotation axis 81 is parallel to the in-track direction 4. In this case, the direction of the media diversion path 245 will be perpendicular to the in-track direction 4, and will therefore have only a lateral component and will have no forward component.
Typically, media sensors (not shown) are used to detect when the media sheet 210 has reached the transfer position 210 and the shifted position 250. Signals from the media sensors are fed into the controller 295 and are used to determine the times that the air sources 86 are activated and deactivated.
The illustrated embodiment shows roller assemblies 260 are positioned at different points along the media diversion path 245. They are spaced such that at least one of the media-guiding rollers 180 will be in contact with the media sheet 210 at all times as it moves along the media diversion path 245. In other embodiments, a single media-guiding roller 180 can be used, or more than two media-guiding rollers 180 can be used, depending on the geometry of the media diversion path.
In the illustrated embodiment, the media-guiding rollers 180 are used to divert the media sheet 210 into the right media path 235, which is shifted laterally to the right of the input media path 205. It will be obvious to those skilled in the art that in other embodiments the left media path 230 can be shifted laterally to the left of the input media path 205 and the media-guiding rollers 180 can be oriented to divert the media sheet 210 into the left media path 235. In other embodiments, different sets of media-guiding rollers 180 that are oriented in different directions to direct the media sheet 210 into a plurality of media paths at different lateral positions. It will be obvious to one skilled in the art that this same approach can be extended to direct the media sheet 210 into more than two media paths.
A pattern of air holes 315 is formed through the exterior surface 310 of the fixed web-guiding structure 305, through which air 325 supplied by an air source 320 can flow. As the web of receiver media 10 travels around the fixed web-guiding structure 305, the flow of air 325 through the air holes 315 serves as an air bearing lifting the web of receiver media 10 away from the fixed web-guiding structure 305 such that first side 15 of the web of receiver media 10 is substantially not in contact with the fixed web-guiding structure 305. Within the context of the present disclosure, “substantially not in contact” means that the receiver media 10 contacts less than 5% of the exterior surface 310 of the fixed web-guiding structure 305 that is adjacent to the receiver media 10. (The fixed web-guiding structure 305 is sometimes referred to in the art as an “air shoe” or an “air bearing structure.”)
As the web of receiver media 10 is supported by the air 325 so that there is minimal contact between the receiver media 10 and the exterior surface 310 of the fixed web-guiding structure 305, the receiver media 10 has minimal friction with the fixed web-guiding structure 305. As a result, the receiver media 10 can pass over the fixed web-guiding structure 305 without scuffing the receiver media 10. Furthermore, the transverse bending of the web of receiver media 10 as it goes around the fixed web-guiding structure 305 tends to flatten the web of receiver media 10. The lack of angular constraint on the receiver media 10 allows the receiver media 10 to spread laterally to enable the flattening of the web. The fixed web-guiding structure 305 can therefore accommodate large wrap angles of the receiver media 10 without wrinkling.
Because the receiver media 10 has minimal friction with the fixed web-guiding structure 305, it provides little or no lateral constraint to impede the lateral (i.e., cross-track) movement of the web of receiver media 10. Therefore, while the low friction is beneficial for inhibiting the formation of wrinkles, it has the detrimental effect of allowing the print media to drift in the cross-track direction 7. The media-guiding system 78, including media-guiding roller 180 and air source 86, is used to provide a lateral constraint on the receiver media 10 by placing it in close proximity to the fixed web-guiding structure 305 to inhibit cross-track drift or wander of the receiver media 10.
It will be obvious to one skilled in the art that in addition to guiding receiver media 10 through a printing system 100, the media guiding systems of the present invention can also be used to guide other types of media in other types of media transport systems. For example, the present invention can also be used to move various kinds of substrates through other types of systems such as media coating systems, or systems for performing various media finishing operations (e.g., slitting, folding or binding).
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
PARTS LIST
- 2 roller
- 3 receiver media
- 4 in-track direction
- 5 flute
- 7 cross-track direction
- 8 contact surface
- 9 exit direction
- 10 receiver media
- 11 source roll
- 12 take-up roll
- 15 first side
- 16 second side
- 20a printhead
- 20b printhead
- 20c printhead
- 20d printhead
- 21 print line
- 22 print line
- 25a printhead
- 25b printhead
- 30 web-guiding system
- 31 print line roller
- 32 print line roller
- 40 dryer
- 41 dryer roller
- 45 quality control sensor
- 50 printing module
- 51 first zone
- 52 second zone
- 55 printing module
- 60 turnover mechanism
- 65 printing module
- 66 web-guiding structure
- 70 media-guiding roller
- 72 rotation direction
- 74 air cushion
- 76 entrained airflow
- 78 media-guiding system
- 79 media-guiding system
- 80 media-guiding roller
- 81 roller axis
- 82 rotation direction
- 83 exterior surface
- 84 groove
- 85 airflow guide
- 86 air source
- 88 air
- 89 openings
- 90 airflow
- 91 plenum
- 92 constriction
- 93 pivot arm
- 94 actuator
- 95 steering controller
- 96 media edge detector
- 97 stepper motor
- 98 rotation axis
- 99 frame
- 100 printing system
- 110 printing system
- 170 media-guiding system
- 171 media-guiding system
- 172 media-guiding system
- 173 media-guiding system
- 174 media-guiding system
- 175 media-guiding system
- 180 media-guiding roller
- 182 spring
- 184 edge stop
- 185 flute detection system
- 195 controller
- 200 sheet-diverter system
- 201 sheet-diverter system
- 202 sheet-diverter system
- 205 input media path
- 210 media sheet
- 212 leading edge
- 215 media guide
- 220 upper media path
- 225 lower media path
- 230 left media path
- 235 right media path
- 240 transfer position
- 245 media diversion path
- 250 shifted position
- 260 roller assembly
- 261 roller assembly
- 280 media-guiding roller
- 281 roller axis
- 282 rotation direction
- 283 exterior surface
- 284 groove
- 286 air source
- 290 airflow
- 292 constriction
- 295 controller
- 300 web-guiding system
- 305 fixed web-guiding structure
- 310 exterior surface
- 315 air holes
- 320 air source
- 325 air
- 370 concave media-guiding roller
- 373 exterior surface
- 375 central portion
- 377 contacting portion
- 380 concave media-guiding roller
- 383 exterior surface
- 384 groove
- da airflow depth
- dg groove depth
- F Bernoulli force
- wg groove width
- α wrap angle
Claims
1. A media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:
- a media-guiding roller having a roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the media travels along the transport path past the media-guiding roller with the first side of the media facing the exterior surface of the media-guiding roller;
- an air source for providing an air flow into one or more of the grooves, the air flow being directed between the first side of the media and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the media-guiding roller and providing an increased traction between the media and the media-guiding roller; and
- a roller control mechanism for adjusting an orientation of the roller axis relative to the in-track direction of the media, thereby providing a steering force to steer the media in a cross-track direction.
2. The media-guiding system of claim 1 further including a control system for selectively activating the air source, wherein when the air source is activated the Bernoulli force draws the media toward the exterior surface of the media-guiding roller providing a higher traction between the media and the media-guiding roller, and when the air source is not activated no Bernoulli force is produced providing a lower traction between the media and the media-guiding roller.
3. The media-guiding system of claim 2 wherein the roller axis is oriented in a non-orthogonal direction relative to the in-track direction such that when the air source is activated the media is steered in a cross-track direction as it passes the media-guiding roller.
4. The media-guiding system of claim 3 further including a media edge detector that detects a position of an edge of the media, and wherein the control system controls the air source in response to a signal from the media edge detector.
5. The media-guiding system of claim 1 further including an edge stop positioned along one edge of the media, wherein the roller axis is oriented to provide a steering force that pushes the media against the edge stop thereby maintaining a substantially constant cross-track position of the media.
6. The media-guiding system of claim 11 wherein the roller axis is substantially perpendicular to the in-track direction.
7. (canceled)
8. The media-guiding system of claim 1 further including a media edge detector that detects a position of an edge of the media, and wherein the roller control mechanism adjusts the orientation of the roller axis in response to a signal from the media edge detector.
9. The media-guiding system of claim 1 wherein the media guiding roller is mounted to a frame, and wherein the roller control mechanism includes an actuator or a stepper motor that adjusts the orientation of the roller axis by rotating the frame around a rotation axis.
10. The media-guiding system of claim 1 wherein the media contacts the media-guiding roller for a wrap angle of less than 5 degrees as it passes the media-guiding roller.
11. A media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:
- a media-guiding roller having a roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the media travels along the transport path past the media-guiding roller with the first side of the media facing the exterior surface of the media-guiding roller;
- an air source for providing an air flow into one or more of the grooves, the air flow being directed between the first side of the media and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the media-guiding roller and providing an increased traction between the media and the media-guiding roller; and
- an air shoe in proximity to the media-guiding roller, wherein the media passes over the air shoe on a cushion of air, and wherein the media-guiding roller stabilizes a cross-track position of the media as the media passes over the air shoe.
12. The media-guiding system of claim 1 wherein the media is a web of media.
13. The media-guiding system of claim 1 wherein the media is a cut sheet of media.
14. The media-guiding system of claim 1 wherein the media-guiding roller spans a cross-track width of the media.
15. The media-guiding system of claim 1 wherein the media-guiding roller has a width in the direction of the roller axis which is less than 20% of a cross-track width of the web of media.
16. A media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:
- a first media-guiding roller having a first roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the first media-guiding roller has a width in the direction of the first roller axis which is less than 20% of a cross-track width of the web of media, and wherein the media travels along the transport path past the first media-guiding roller with the first side of the media facing the exterior surface of the first media-guiding roller;
- a first air source for providing an air flow into one or more of the grooves formed around the exterior surface of the first media-guiding roller, the air flow being directed between the first side of the media and the exterior surface of the first media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the first media-guiding roller and providing an increased traction between the media and the first media-guiding roller;
- a second media-guiding roller having a second roller axis and an exterior surface having one or more grooves formed around the exterior surface, wherein the second media-guiding roller has a width in the direction of the second roller axis which is less than 20% of the cross-track width of the web of media; and
- a second air source for providing an air flow into one or more of the grooves formed around the exterior surface of the second media-guiding roller, the air flow being directed between the first side of the media and the exterior surface of the second media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the second media-guiding roller and providing an increased traction between the media and the second media-guiding roller.
17. The media-guiding system of claim 16 wherein the first media-guiding roller is located in proximity to a first edge of the media and the second media-guiding roller is located in proximity to an opposite second edge of the media.
18. The media-guiding system of claim 17 the first roller axis is not parallel to the second roller axis to provide a stretching force or a compressing force to the media in the cross-track direction.
19. The media-guiding system of claim 1 further including a drive mechanism that rotates the media-guiding roller around its roller axis.
20. The media-guiding system of claim 1 wherein the media-guiding roller has a plurality of grooves, and wherein a separate air source is used to provide the air flow into each of the grooves.
21. The media-guiding system of claim 1 wherein the media-guiding roller has a plurality of grooves, and wherein the air source includes a plenum having openings corresponding to each of the grooves to direct the air flow into the corresponding grooves.
22. The media-guiding system of claim 1 wherein the air flow is directed into the one or more of the grooves in a direction substantially parallel to the grooves.
23. The media-guiding system of claim 1 wherein the exterior surface of the media-guiding roller is concave.
24. A media-guiding system for guiding a media travelling from upstream to downstream along a transport path in an in-track direction, the media having a first side and an opposing second side, comprising:
- a media-guiding roller having a roller axis and an exterior surface having a plurality of grooves formed around the exterior surface, wherein the media travels along the transport path past the media-guiding roller with the first side of the media facing the exterior surface of the media-guiding roller; and
- a plurality of air sources for providing air flow into the grooves, the air flow being directed between the first side of the media and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media toward the exterior surface of the media-guiding roller and providing an increased traction between the media and the media-guiding roller, wherein a separate air source is used to provide the air flow into each of the grooves.
Type: Application
Filed: Feb 26, 2014
Publication Date: Aug 27, 2015
Inventors: Christopher M. Muir (Rochester, NY), David James Cornell (Scottsville, NY)
Application Number: 14/190,125