US20010022428A1 - Variable cross-section vaccuum grooves in an external drum imaging system - Google Patents
Variable cross-section vaccuum grooves in an external drum imaging system Download PDFInfo
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- US20010022428A1 US20010022428A1 US09/843,050 US84305001A US2001022428A1 US 20010022428 A1 US20010022428 A1 US 20010022428A1 US 84305001 A US84305001 A US 84305001A US 2001022428 A1 US2001022428 A1 US 2001022428A1
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- vacuum
- groove
- vacuum groove
- section
- support surface
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/06—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
- H04N1/08—Mechanisms for mounting or holding the sheet around the drum
- H04N1/0804—Holding methods
- H04N1/0821—Holding substantially the whole of the sheet, e.g. with a retaining sheet
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/06—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
- H04N1/08—Mechanisms for mounting or holding the sheet around the drum
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/06—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
- H04N1/08—Mechanisms for mounting or holding the sheet around the drum
- H04N1/083—Holding means
- H04N1/0856—Suction or vacuum means
- H04N1/086—Suction or vacuum means using grooves
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/06—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
- H04N1/08—Mechanisms for mounting or holding the sheet around the drum
- H04N1/083—Holding means
- H04N1/0869—Holding means capable of holding different sized sheets
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/06—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
- H04N1/08—Mechanisms for mounting or holding the sheet around the drum
- H04N1/083—Holding means
- H04N1/0873—Holding means for holding the sheet on the internal surface of the drum
Definitions
- the present invention is in the field of imaging systems. More particularly, the present invention provides a method and apparatus for holding recording media against a media support surface of an imaging system using an arrangement of variable cross-section vacuum grooves.
- a movable optical carriage is used to displace a laser system or other imaging source in a slow scan direction along a curved or planar media support surface (e.g., flatbed, internal drum, external drum, or other support surface).
- the imaging source exposes a supply of recording media supported on, and held against, the media support surface.
- the imaging source includes an optical system for scanning one or more laser or other radiation beams modulated by an information signal over the recording media to record an image onto the recording media.
- the imaging source may include a beam deflection assembly, comprising a deflector element (e.g., a mirror) and a spin motor for rotating the deflector element, wherein the beam deflection assembly deflects an imaging beam generated by a radiation source across the recording media.
- a beam deflection assembly comprising a deflector element (e.g., a mirror) and a spin motor for rotating the deflector element, wherein the beam deflection assembly deflects an imaging beam generated by a radiation source across the recording media.
- the recording media to be imaged by an imaging system is commonly supplied in web form or in discrete sheets or plates.
- the recording media may comprise a photosensitive, radiation sensitive, thermally sensitive, or other type of imageable material.
- different size recording media may be used for different applications, depending on such factors as the type of image to be scanned, etc.
- a vacuum system is employed to hold the recording media against the media support surface.
- the vacuum system operates by drawing a vacuum through a plurality of vacuum ports, disposed over the media support surface, which draw air from a plurality of constant cross-section (e.g., constant depth and width) vacuum grooves.
- a single vacuum source is used to draw air from each of the vacuum ports, larger recording media is held more firmly against the media support surface than smaller recording media because the larger recording media covers more of the vacuum ports or grooves.
- smaller recording media is held less firmly against the media support surface than larger recording media because of the air loss through the vacuum ports or grooves not covered by the smaller recording media, or a drop in vacuum caused by constant cross-section groove drag and loss. This may become problematic when the recording media comprises a flat aluminum plate or the like which is to be held on a curved media support surface, since the vacuum forces required to hold the aluminum plate firmly against the media support surface may be quite substantial.
- the present invention provides a method and apparatus for holding recording media against a media support surface of an imaging system using an arrangement of variable cross-section vacuum grooves.
- the present invention provides an apparatus comprising:
- At least one variable depth vacuum groove in the media support surface At least one variable depth vacuum groove in the media support surface.
- each vacuum groove has a continuously decreasing depth along its length, wherein the vacuum groove has a maximum depth adjacent a vacuum port and a minimum depth at a distal end of the vacuum groove.
- the depth of each vacuum groove may comprise, e.g., a series of stepped sections each having a gradually reduced depth.
- Other variable depth vacuum groove configurations are possible without departing from the scope of the present invention.
- the present invention additionally provides a method for holding media on a media support surface, comprising the steps of:
- the present invention provides an apparatus comprising:
- At least one variable cross-section vacuum groove in the support surface At least one variable cross-section vacuum groove in the support surface.
- variable cross-section of each vacuum groove may be provided using any suitable method that provides a cross-section that decreases from a maximum adjacent a vacuum source/port to a minimum at a distal end of the vacuum groove.
- a variable cross-section may be provided by varying the depth of the vacuum groove along its length (constant width).
- a variable cross-section may be provided by varying the width of the vacuum groove along its length (constant depth).
- a variable cross-section may be provided by varying both the depth and width of the vacuum groove along its length. Many other techniques or combination of techniques are also possible without departing from the scope of the present invention.
- the present invention additionally provides an imaging system comprising:
- a media support surface for supporting a supply of recording media
- FIG. 2 illustrates the movable optical carriage, scanning system, and vacuum groove arrangement of the imaging system of FIG. 1;
- FIG. 3 is a partial plan view of the internal drum of the imaging system of FIG. 1, illustrating an arrangement of variable cross-section vacuum grooves in accordance with the present invention
- FIG. 4 is a cross-sectional view illustrating a variable cross-section vacuum groove in an internal drum in accordance with the present invention
- FIG. 5 is a cross-sectional view illustrating a variable cross-section vacuum groove in an external drum in accordance with the present invention
- FIG. 6 is a cross-sectional view illustrating a variable cross-section vacuum groove in an planar media support surface in accordance with the present invention
- FIGS. 7A and 7B illustrate a cross-sectional and plan view, respectively, of a variable cross-section vacuum groove having a constant depth and variable width
- FIGS. 8A and 8B illustrate a cross-sectional and plan view, respectively, of a variable cross-section vacuum groove having a variable depth and variable width
- FIGS. 9A and 9B illustrate examples of possible polygonal groove cross-sections
- FIGS. 10A and 10B illustrate examples of possible arcuate groove cross-sections.
- FIG. 1 An example of an imaging system 10 is illustrated in FIG. 1.
- the imaging system 10 comprises an internal drum imagesetter configured to record digital data onto a supply of film, a printing plate, or other recording media.
- an internal drum imagesetter configured to record digital data onto a supply of film, a printing plate, or other recording media.
- the present invention may be used in conjunction with a wide variety of other types of internal drum, external drum, flatbed, or capstan type imaging systems, including platesetters and the like, without departing from the intended scope of the present invention as set forth in the claims.
- the imaging system 10 generally includes a front end computer or workstation 12 for the design and layout of pages to be printed, a raster image processor (RIP) 14 for rasterizing the page data, and an imagesetter 16 .
- the imagesetter 16 records the digital data provided by the RIP 14 onto a supply of photosensitive, radiation sensitive, thermally sensitive, or other type of suitable recording media 18 .
- the recording media 18 is provided in web form or in discrete sheets or plates by a media supply system 60 .
- the imagesetter 16 includes an internal drum 20 having a cylindrical media support surface 22 for supporting and positioning the recording media 18 during imaging.
- the imagesetter 16 further includes a scanning system 24 , carried by a movable optical carriage 26 , for recording digital data onto the recording media 18 using an imaging beam 28 .
- At least one side punch 50 is positioned and attached in a known manner to an end of the internal drum 20 .
- the punches 50 are used to punch a predetermined set of registration holes, notches, etc., in the recording media 18 .
- the scanning system 24 is displaced by the movable optical carriage 26 in a slow scan direction (directional arrow A) along the internal drum 20 to expose the recording media 18 in a line-wise manner.
- the optical carriage 26 is preferably displaced by an onboard drive system (not shown), although an external drive system may also be used.
- the scanning system 24 typically includes a laser system 30 for generating the imaging beam 28 .
- the laser system 30 comprises a light or radiation source 32 for producing the imaging beam 28 , and an optical system 34 positioned between the radiation source 32 and the media support surface 22 for focusing the imaging beam 28 onto the recording media 18 .
- the imaging beam 28 exits the optical system 34 through a spot focusing lens 36 .
- the scanning system 24 further includes a beam deflection assembly 38 for deflecting the imaging beam 28 across the recording media 18 in a fast scan curvilinear direction B (see FIG. 1) to record a scan line on the imaging surface 21 of the recording media 18 .
- the beam deflection assembly 38 comprises a deflector element 40 (e.g., a mirror) and a spin motor 42 for rotating the deflector element 40 .
- a deflector element 40 e.g., a mirror
- a spin motor 42 for rotating the deflector element 40 .
- the imaging beam 28 is scanned across the recording media 18 as shown in FIG. 1, thereby imaging a scan line on the recording media 18 .
- the scanning system 24 described above is only one of many different types of scanning systems that may be used to record image data on the recording media 18 .
- the recording media 18 is held against the media support surface 22 by drawing a vacuum through a plurality of vacuum ports using a vacuum pump, venturi vacuum device, or other vacuum source.
- a plurality of vacuum grooves 70 are formed in the media support surface 22 , such that as air is drawn from a vacuum port, the air in a corresponding vacuum groove 70 is evacuated, thereby drawing the recording media 18 into contact with the media support surface 22 .
- the vacuum grooves 70 may be organized in a wide variety of arrangements, and may be formed in a wide variety of configurations (e.g., shapes, cross-sections, etc.).
- the vacuum grooves 70 may have a variable cross-section (e.g., variable depth) that decreases with distance from the vacuum port.
- the vacuum grooves 70 may have a linear configuration, with a variable depth and a constant groove width, and may be arranged in parallel, equally spaced, along the fast scan curvilinear direction B (FIG. 1). Alternately, the vacuum grooves 70 may be arranged in parallel, equally spaced, along the slow scan direction.
- the vacuum grooves 70 may have a “zigzag” or other non-linear arrangement, and may be arranged in a particular configuration in the media support surface 22 .
- a single groove that “snakes” along the media support surface and which is supplied with a vacuum through one or more vacuum ports may be used.
- the configuration of vacuum grooves and/or each individual vacuum groove includes a decreasing cross-section.
- FIG. 3 A partial plan view of the internal drum 20 of the imaging system 10 of FIG. 1, illustrating an arrangement of variable cross-section grooves 70 in accordance with the present invention, is illustrated in FIG. 3. As shown, a plurality of equally spaced vacuum grooves 70 are arranged in parallel along the fast scan curvilinear direction. Each vacuum groove 70 has a constant width W, and a depth that varies continuously from a maximum at a vacuum port 72 to a minium at a distal end 74 of the vacuum groove. Each vacuum groove 70 is associated with a single vacuum port 72 formed in a vacuum manifold 75 .
- a vacuum source 76 supplies a vacuum to the vacuum manifold 75 , which in turn simultaneously supplies a vacuum to a selected plurality of vacuum ports 72 and associated vacuum grooves 70 .
- a substantially uniform vacuum is generated along the entire length of the plurality of vacuum grooves 70 .
- This produces a uniform vacuum level that draws the entire area of the recording media onto the media support surface throughout the internal drum 20 .
- This vacuum level is capable of firmly holding different sizes/types of recording media against the media support surface 22 , without the need for a complex and expensive vacuum and manifold system.
- a simple vacuum manifold system 120 may be used to apply a vacuum to a selected plurality of the vacuum ports 72 and associated vacuum grooves 70 according to the size of the recording media 18 .
- the vacuum manifold system 120 includes a piston 122 located within the vacuum manifold 75 and a drive system 124 (e.g., a lead screw and motor for rotating the lead screw) for selectively displacing the piston 122 within the vacuum manifold 75 .
- a drive system 124 e.g., a lead screw and motor for rotating the lead screw
- This arrangement may be used, for example, to hold a plate P 1 against the media support surface 22 .
- the piston 122 is positioned at location L 2 (shown in phantom) by the drive system 124 , a vacuum is only applied to the vacuum ports 72 and vacuum grooves 70 located between points P 1 and P 3 .
- the vacuum was sufficient to firmly hold recording media of different sizes (e.g., 18 ⁇ 14.4 inches (450 ⁇ 360 mm) to 45.2 ⁇ 32 inches (1130 ⁇ 800 mm)) and types (e.g., 0.006 to 0.012 inches (0.152 to 0.305 mm) thick aluminum plates for a lithographic thermal process) against the media support surface of the internal drum.
- recording media e.g., 18 ⁇ 14.4 inches (450 ⁇ 360 mm) to 45.2 ⁇ 32 inches (1130 ⁇ 800 mm)
- types e.g., 0.006 to 0.012 inches (0.152 to 0.305 mm) thick aluminum plates for a lithographic thermal process
- a plurality of the vacuum grooves 70 are formed in a media support surface 86 of the external drum 80 .
- the vacuum grooves 70 may be organized in a wide variety of arrangements, and may be formed in a wide variety of configurations (e.g., shapes, cross-sections, etc.), wherein at least some (preferably all) of the vacuum grooves 70 have a variable cross-section (e.g., variable depth) that decreases along their length.
- each vacuum groove 70 decreases continuously along its length, a substantially uniform vacuum is generated along the entire length of the plurality of vacuum grooves 70 . This produces a more uniform vacuum level around the external drum 80 , which is capable of firmly holding different sizes/types of recording media against the media support surface 86 .
- FIG. 6 illustrates a cross-section of a variable cross-section vacuum groove 70 in an imaging system that includes a planar media support surface 100 .
- the vacuum groove 70 in FIG. 6 is again exaggerated in size relative to the media support surface 100 to more clearly depict the variability of the groove depth.
- the vacuum groove 70 has a maximum depth D max at a vacuum port 102 , a minimum depth D min at the distal end 104 of the vacuum groove, and a constant width.
- the depth of the vacuum groove 70 decreases continuously along the length of the vacuum groove 70 from the vacuum port 102 to the distal end 104 .
- a plurality of the vacuum grooves 70 are formed in the media support surface 100 .
- the vacuum grooves 70 may be organized in a wide variety of arrangements, and may be formed in a wide variety of configurations (e.g., shapes, cross-sections, etc.), wherein at least some (preferably all) of the vacuum grooves 70 have a variable cross-section (e.g., variable depth) that decreases along their length.
- a plurality of the vacuum grooves 70 may be arranged in parallel, equally spaced, along the media support surface 100 .
- a supply of recording media 18 provided in a known manner by a media a media supply system 108 , is held against the media support surface 100 by drawing a vacuum through a plurality of vacuum grooves 70 formed in the media support surface 100 .
- a scanning system 110 records digital data provided onto the recording media 18 in a known manner (e.g., using a laser system).
- each vacuum groove 70 is formed with a variable cross-section that decreases along its length.
- each vacuum groove 70 has a constant width and a depth that decreases along its length.
- Many other cross-sectional configurations or combinations of cross-sectional configurations are also possible.
- vacuum groove 70 may have a constant depth and a width that decreases along its length, thereby providing a decreasing cross-section.
- the vacuum groove 70 may have both a variable depth and a variable width along its length.
- the vacuum groove 70 may have a polygonal cross-section other than the rectangular cross-section detailed above.
- FIGS. 9A and 9B Examples of different polygonal cross-sections are illustrated in FIGS. 9A and 9B.
- the vacuum groove 70 may also have an arcuate configuration as shown in FIGS. 10A and 10B. Regardless of the specific cross-sectional configuration, the cross-section of each vacuum groove decreases in some manner, continuously or discretely, along its length.
- variable cross-section grooves of the present invention are described for use in imaging systems, it should be readily apparent that the variable cross-section grooves could be used in any type of system wherein a supply of a material is to be held against a support surface using a vacuum.
- Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.
Abstract
Description
- The present invention is in the field of imaging systems. More particularly, the present invention provides a method and apparatus for holding recording media against a media support surface of an imaging system using an arrangement of variable cross-section vacuum grooves.
- In many imaging systems, such as imagesetters or platesetters, a movable optical carriage is used to displace a laser system or other imaging source in a slow scan direction along a curved or planar media support surface (e.g., flatbed, internal drum, external drum, or other support surface). The imaging source exposes a supply of recording media supported on, and held against, the media support surface. Generally, the imaging source includes an optical system for scanning one or more laser or other radiation beams modulated by an information signal over the recording media to record an image onto the recording media. For example, in an internal drum recording system, the imaging source may include a beam deflection assembly, comprising a deflector element (e.g., a mirror) and a spin motor for rotating the deflector element, wherein the beam deflection assembly deflects an imaging beam generated by a radiation source across the recording media.
- The recording media to be imaged by an imaging system is commonly supplied in web form or in discrete sheets or plates. The recording media may comprise a photosensitive, radiation sensitive, thermally sensitive, or other type of imageable material. In a given imaging system, different size recording media may be used for different applications, depending on such factors as the type of image to be scanned, etc. Regardless of the size of the recording media that is used, however, it is important to hold the recording media firmly against the media support surface. Any lifting of the recording media away from the media support surface may result in an out of focus image on the recording media. This may be due, for example, to the fixed and short focal depth of the imaging beam, as well as other factors.
- In many imaging systems, a vacuum system is employed to hold the recording media against the media support surface. Commonly, the vacuum system operates by drawing a vacuum through a plurality of vacuum ports, disposed over the media support surface, which draw air from a plurality of constant cross-section (e.g., constant depth and width) vacuum grooves. When a single vacuum source is used to draw air from each of the vacuum ports, larger recording media is held more firmly against the media support surface than smaller recording media because the larger recording media covers more of the vacuum ports or grooves. Analogously, smaller recording media is held less firmly against the media support surface than larger recording media because of the air loss through the vacuum ports or grooves not covered by the smaller recording media, or a drop in vacuum caused by constant cross-section groove drag and loss. This may become problematic when the recording media comprises a flat aluminum plate or the like which is to be held on a curved media support surface, since the vacuum forces required to hold the aluminum plate firmly against the media support surface may be quite substantial.
- Many attempts have been made to provide a vacuum system capable of providing a sufficient vacuum for different size recording media. One such technique is described in U.S. Pat. Nos. 6,133,936 and 6,047,733, both incorporated herein by reference in their entirety. This technique employs a sequencing manifold to selectively draw a vacuum through a plurality of individually addressable vacuum sections depending on the size of the recording media. Unfortunately, such a vacuum and manifold system, although quite effective, is generally highly complex and expensive to produce.
- The present invention provides a method and apparatus for holding recording media against a media support surface of an imaging system using an arrangement of variable cross-section vacuum grooves.
- Generally, in accordance with a preferred embodiment, the present invention provides an apparatus comprising:
- a media support surface; and
- at least one variable depth vacuum groove in the media support surface.
- Preferably, each vacuum groove has a continuously decreasing depth along its length, wherein the vacuum groove has a maximum depth adjacent a vacuum port and a minimum depth at a distal end of the vacuum groove. However, the depth of each vacuum groove may comprise, e.g., a series of stepped sections each having a gradually reduced depth. Other variable depth vacuum groove configurations are possible without departing from the scope of the present invention.
- The present invention additionally provides a method for holding media on a media support surface, comprising the steps of:
- positioning the media over at least one variable depth vacuum groove in the media support surface; and
- applying a vacuum to the vacuum grooves.
- Even more generally, the present invention provides an apparatus comprising:
- a support surface; and
- at least one variable cross-section vacuum groove in the support surface.
- The variable cross-section of each vacuum groove may be provided using any suitable method that provides a cross-section that decreases from a maximum adjacent a vacuum source/port to a minimum at a distal end of the vacuum groove. For example, as detailed above, a variable cross-section may be provided by varying the depth of the vacuum groove along its length (constant width). Alternately, a variable cross-section may be provided by varying the width of the vacuum groove along its length (constant depth). Further, a variable cross-section may be provided by varying both the depth and width of the vacuum groove along its length. Many other techniques or combination of techniques are also possible without departing from the scope of the present invention.
- The present invention additionally provides an imaging system comprising:
- a media support surface for supporting a supply of recording media;
- at least one variable cross-section vacuum groove in the media support surface;
- a system for applying a vacuum to each vacuum groove to hold the recording media against the media support surface; and
- a system for recording image data onto the recording media.
- The features of the present invention will best be understood from a detailed description of the invention and a preferred embodiment thereof selected for the purposes of illustration and shown in the accompanying drawings in which:
- FIG. 1 illustrates an example of an imaging system for recording images onto a supply of recording media;
- FIG. 2 illustrates the movable optical carriage, scanning system, and vacuum groove arrangement of the imaging system of FIG. 1;
- FIG. 3 is a partial plan view of the internal drum of the imaging system of FIG. 1, illustrating an arrangement of variable cross-section vacuum grooves in accordance with the present invention;
- FIG. 4 is a cross-sectional view illustrating a variable cross-section vacuum groove in an internal drum in accordance with the present invention;
- FIG. 5 is a cross-sectional view illustrating a variable cross-section vacuum groove in an external drum in accordance with the present invention;
- FIG. 6 is a cross-sectional view illustrating a variable cross-section vacuum groove in an planar media support surface in accordance with the present invention;
- FIGS. 7A and 7B illustrate a cross-sectional and plan view, respectively, of a variable cross-section vacuum groove having a constant depth and variable width;
- FIGS. 8A and 8B illustrate a cross-sectional and plan view, respectively, of a variable cross-section vacuum groove having a variable depth and variable width;
- FIGS. 9A and 9B illustrate examples of possible polygonal groove cross-sections; and
- FIGS. 10A and 10B illustrate examples of possible arcuate groove cross-sections.
- The features and advantages of the present invention are illustrated in detail in the accompanying drawings, wherein like reference numerals refer to like elements throughout the drawings. Although the drawings are intended to illustrate the present invention, the drawings are not necessarily drawn to scale.
- An example of an
imaging system 10 is illustrated in FIG. 1. In this example, theimaging system 10 comprises an internal drum imagesetter configured to record digital data onto a supply of film, a printing plate, or other recording media. Although described below with regard to an internal drum imagesetter, the present invention may be used in conjunction with a wide variety of other types of internal drum, external drum, flatbed, or capstan type imaging systems, including platesetters and the like, without departing from the intended scope of the present invention as set forth in the claims. - The
imaging system 10 generally includes a front end computer orworkstation 12 for the design and layout of pages to be printed, a raster image processor (RIP) 14 for rasterizing the page data, and animagesetter 16. Theimagesetter 16 records the digital data provided by theRIP 14 onto a supply of photosensitive, radiation sensitive, thermally sensitive, or other type ofsuitable recording media 18. Therecording media 18 is provided in web form or in discrete sheets or plates by amedia supply system 60. - The
imagesetter 16 includes aninternal drum 20 having a cylindricalmedia support surface 22 for supporting and positioning therecording media 18 during imaging. Theimagesetter 16 further includes ascanning system 24, carried by a movableoptical carriage 26, for recording digital data onto therecording media 18 using animaging beam 28. - At least one
side punch 50 is positioned and attached in a known manner to an end of theinternal drum 20. Thepunches 50 are used to punch a predetermined set of registration holes, notches, etc., in therecording media 18. By aligning the image recorded by thescanning system 24 onto therecording media 18 to the set of holes in therecording media 18, accurate registration throughout the prepress process can be achieved. - As illustrated in FIG. 2, the
scanning system 24 is displaced by the movableoptical carriage 26 in a slow scan direction (directional arrow A) along theinternal drum 20 to expose therecording media 18 in a line-wise manner. Theoptical carriage 26 is preferably displaced by an onboard drive system (not shown), although an external drive system may also be used. - The
scanning system 24 typically includes alaser system 30 for generating theimaging beam 28. Thelaser system 30 comprises a light orradiation source 32 for producing theimaging beam 28, and anoptical system 34 positioned between theradiation source 32 and themedia support surface 22 for focusing theimaging beam 28 onto therecording media 18. Theimaging beam 28 exits theoptical system 34 through aspot focusing lens 36. Thescanning system 24 further includes abeam deflection assembly 38 for deflecting theimaging beam 28 across therecording media 18 in a fast scan curvilinear direction B (see FIG. 1) to record a scan line on theimaging surface 21 of therecording media 18. Thebeam deflection assembly 38 comprises a deflector element 40 (e.g., a mirror) and aspin motor 42 for rotating thedeflector element 40. As thedeflector element 40 is rotated by thespin motor 42, theimaging beam 28 is scanned across therecording media 18 as shown in FIG. 1, thereby imaging a scan line on therecording media 18. Thescanning system 24 described above is only one of many different types of scanning systems that may be used to record image data on therecording media 18. - In the
imaging system 10, therecording media 18 is held against themedia support surface 22 by drawing a vacuum through a plurality of vacuum ports using a vacuum pump, venturi vacuum device, or other vacuum source. As illustrated in FIG. 2, a plurality ofvacuum grooves 70, each associated with one of the vacuum ports, are formed in themedia support surface 22, such that as air is drawn from a vacuum port, the air in acorresponding vacuum groove 70 is evacuated, thereby drawing therecording media 18 into contact with themedia support surface 22. Thevacuum grooves 70 may be organized in a wide variety of arrangements, and may be formed in a wide variety of configurations (e.g., shapes, cross-sections, etc.). Regardless of the specific arrangement and configuration of thevacuum grooves 70 used in theimaging system 10, and in accordance with the present invention, at least some (preferably all) of thevacuum grooves 70 have a variable cross-section (e.g., variable depth) that decreases with distance from the vacuum port. For example, as illustrated in FIGS. 2-4, thevacuum grooves 70 may have a linear configuration, with a variable depth and a constant groove width, and may be arranged in parallel, equally spaced, along the fast scan curvilinear direction B (FIG. 1). Alternately, thevacuum grooves 70 may be arranged in parallel, equally spaced, along the slow scan direction. In other applications, thevacuum grooves 70 may have a “zigzag” or other non-linear arrangement, and may be arranged in a particular configuration in themedia support surface 22. In addition, a single groove that “snakes” along the media support surface and which is supplied with a vacuum through one or more vacuum ports may be used. The configuration of vacuum grooves and/or each individual vacuum groove includes a decreasing cross-section. - A partial plan view of the
internal drum 20 of theimaging system 10 of FIG. 1, illustrating an arrangement ofvariable cross-section grooves 70 in accordance with the present invention, is illustrated in FIG. 3. As shown, a plurality of equally spacedvacuum grooves 70 are arranged in parallel along the fast scan curvilinear direction. Eachvacuum groove 70 has a constant width W, and a depth that varies continuously from a maximum at avacuum port 72 to a minium at adistal end 74 of the vacuum groove. Eachvacuum groove 70 is associated with asingle vacuum port 72 formed in avacuum manifold 75. Avacuum source 76 supplies a vacuum to thevacuum manifold 75, which in turn simultaneously supplies a vacuum to a selected plurality ofvacuum ports 72 and associatedvacuum grooves 70. Advantageously, since the depth of eachvacuum groove 70 decreases continuously along its length, a substantially uniform vacuum is generated along the entire length of the plurality ofvacuum grooves 70. This produces a uniform vacuum level that draws the entire area of the recording media onto the media support surface throughout theinternal drum 20. This vacuum level is capable of firmly holding different sizes/types of recording media against themedia support surface 22, without the need for a complex and expensive vacuum and manifold system. - A simple
vacuum manifold system 120 may be used to apply a vacuum to a selected plurality of thevacuum ports 72 and associatedvacuum grooves 70 according to the size of therecording media 18. As illustrated in FIG. 3, thevacuum manifold system 120 includes apiston 122 located within thevacuum manifold 75 and a drive system 124 (e.g., a lead screw and motor for rotating the lead screw) for selectively displacing thepiston 122 within thevacuum manifold 75. For example, when thepiston 122 is positioned at location L1 by thedrive system 124, a vacuum is only applied to thevacuum ports 72 andvacuum grooves 70 located between points P1 and P2. All of the remainingvacuum ports 72 remain blocked by thepiston 122. This arrangement may be used, for example, to hold a plate P1 against themedia support surface 22. Similarly, when thepiston 122 is positioned at location L2 (shown in phantom) by thedrive system 124, a vacuum is only applied to thevacuum ports 72 andvacuum grooves 70 located between points P1 and P3. - FIG. 4 illustrates a cross-section of a variable
cross-section vacuum groove 70 in aninternal drum 20 in accordance with the present invention. Thevacuum groove 70 in FIG. 4 is exaggerated in size relative to theinternal drum 20 to more clearly depict the variability of the groove depth. As shown, thevacuum groove 70 has a maximum depth Dmax at thevacuum port 72, a minimum depth Dmin at thedistal end 74 of the vacuum groove, and a constant width. In the preferred embodiment of the present invention, the depth of thevacuum groove 70 decreases continuously along the length of thevacuum groove 70 from thevacuum port 72 to thedistal end 74. - As an example, an internal drum having a length of approximately 45 inches (1143.00 mm) and a diameter of approximately 19 inches (482.60 mm) was provided with a series of 59 parallel vacuum grooves arranged along the fast scan curvilinear direction. The vacuum grooves were separated by about 0.75 inches (19.05 mm) and each had a constant width of about 0.078 inches (1.98 mm). The depth of each vacuum groove varied continuously from about 0.038 inches (0.965 mm) to about 0.006 inches (0.152 mm) (i.e., by a factor of about 6.33) along the length of the vacuum groove. A supply of recording media was placed on the internal drum and a vacuum of about 17 in-Hg (431.8 mm-Hg) was applied to each of the 59 vacuum grooves. A substantially uniform vacuum of greater than 12 in-Hg (304.8 mm-Hg) was generated along about 85% of the length of each of the 59 vacuum grooves, with a sloping decay never less than 3 in-Hg (76.2 mm-Hg) at the last inch of recording media. The vacuum was sufficient to firmly hold recording media of different sizes (e.g., 18×14.4 inches (450×360 mm) to 45.2×32 inches (1130×800 mm)) and types (e.g., 0.006 to 0.012 inches (0.152 to 0.305 mm) thick aluminum plates for a lithographic thermal process) against the media support surface of the internal drum.
- Generally, for aluminum plates having a thickness of about 0.006 to 0.020 inches (0.150 to 0.500 mm), it has been found that, for an applied vacuum in the range of about X-Y in-Hg ( X′-Y′ mm-Hg), a sufficient vacuum level can be generated by varying the cross-section of each vacuum groove by a factor in the range of about 7 to 1 from a first end of the vacuum groove adjacent the vacuum port to a second distal end of the vacuum groove.
- FIG. 5 illustrates a cross-section of a variable
cross-section vacuum groove 70 in anexternal drum 80 of an externaldrum imaging system 100 in accordance with the present invention. Thevacuum groove 70 in FIG. 5 is again exaggerated in size relative to theexternal drum 80 to more clearly depict the variability of the groove depth. As shown, thevacuum groove 70 has a maximum depth Dmax at avacuum port 82, a minimum depth Dmin at thedistal end 84 of the vacuum groove, and a constant width. The depth of thevacuum groove 70 decreases continuously along the length of thevacuum groove 70 from thevacuum port 82 to thedistal end 84. - A plurality of the
vacuum grooves 70 are formed in amedia support surface 86 of theexternal drum 80. As described above, thevacuum grooves 70 may be organized in a wide variety of arrangements, and may be formed in a wide variety of configurations (e.g., shapes, cross-sections, etc.), wherein at least some (preferably all) of thevacuum grooves 70 have a variable cross-section (e.g., variable depth) that decreases along their length. - A supply of
recording media 18, provided by a media amedia supply system 88, is held against themedia support surface 86 of theexternal drum 80 by drawing a vacuum through a plurality ofvacuum grooves 70 formed in themedia support surface 86. Ascanning system 90 records digital data provided by a RIP (see FIG. 1) onto therecording media 18 in a known manner (e.g., using a laser system). As known in the art, the digital data is recorded onto therecording media 18 by displacing thescanning system 90 relative to theexternal drum 80. This may be accomplished in a number of ways, including a rotation of theexternal drum 80 along with a lateral translation of the scanning system, a rotation and translation of the external drum past a stationary scanning system, etc. - Since the depth of each
vacuum groove 70 decreases continuously along its length, a substantially uniform vacuum is generated along the entire length of the plurality ofvacuum grooves 70. This produces a more uniform vacuum level around theexternal drum 80, which is capable of firmly holding different sizes/types of recording media against themedia support surface 86. - FIG. 6 illustrates a cross-section of a variable
cross-section vacuum groove 70 in an imaging system that includes a planarmedia support surface 100. Thevacuum groove 70 in FIG. 6 is again exaggerated in size relative to themedia support surface 100 to more clearly depict the variability of the groove depth. As shown, thevacuum groove 70 has a maximum depth Dmax at avacuum port 102, a minimum depth Dmin at thedistal end 104 of the vacuum groove, and a constant width. The depth of thevacuum groove 70 decreases continuously along the length of thevacuum groove 70 from thevacuum port 102 to thedistal end 104. - A plurality of the
vacuum grooves 70 are formed in themedia support surface 100. Thevacuum grooves 70 may be organized in a wide variety of arrangements, and may be formed in a wide variety of configurations (e.g., shapes, cross-sections, etc.), wherein at least some (preferably all) of thevacuum grooves 70 have a variable cross-section (e.g., variable depth) that decreases along their length. For example, a plurality of thevacuum grooves 70 may be arranged in parallel, equally spaced, along themedia support surface 100. - A supply of
recording media 18, provided in a known manner by a media amedia supply system 108, is held against themedia support surface 100 by drawing a vacuum through a plurality ofvacuum grooves 70 formed in themedia support surface 100. Ascanning system 110 records digital data provided onto therecording media 18 in a known manner (e.g., using a laser system). - As detailed above, each
vacuum groove 70 is formed with a variable cross-section that decreases along its length. In the preferred embodiment, eachvacuum groove 70 has a constant width and a depth that decreases along its length. Many other cross-sectional configurations or combinations of cross-sectional configurations are also possible. For example, as illustrated in FIGS. 7A and 7B,vacuum groove 70 may have a constant depth and a width that decreases along its length, thereby providing a decreasing cross-section. Alternately, as shown in FIGS. 8A and 8B, thevacuum groove 70 may have both a variable depth and a variable width along its length. Thevacuum groove 70 may have a polygonal cross-section other than the rectangular cross-section detailed above. Examples of different polygonal cross-sections are illustrated in FIGS. 9A and 9B. Thevacuum groove 70 may also have an arcuate configuration as shown in FIGS. 10A and 10B. Regardless of the specific cross-sectional configuration, the cross-section of each vacuum groove decreases in some manner, continuously or discretely, along its length. - The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible in light of the above teaching. For example, although the variable cross-section grooves of the present invention are described for use in imaging systems, it should be readily apparent that the variable cross-section grooves could be used in any type of system wherein a supply of a material is to be held against a support surface using a vacuum. Such modifications and variations that may be apparent to a person skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.
Claims (20)
Priority Applications (1)
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US09/843,050 US6450496B2 (en) | 1999-07-22 | 2001-04-26 | Variable cross-section vacuum grooves in an external drum imaging system |
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US09/358,957 US6254091B1 (en) | 1999-07-22 | 1999-07-22 | Variable cross-section vacuum grooves in an imaging system |
US09/843,050 US6450496B2 (en) | 1999-07-22 | 2001-04-26 | Variable cross-section vacuum grooves in an external drum imaging system |
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US09/358,957 Continuation US6254091B1 (en) | 1999-07-22 | 1999-07-22 | Variable cross-section vacuum grooves in an imaging system |
US09/358,957 Division US6254091B1 (en) | 1999-07-22 | 1999-07-22 | Variable cross-section vacuum grooves in an imaging system |
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US20010022428A1 true US20010022428A1 (en) | 2001-09-20 |
US6450496B2 US6450496B2 (en) | 2002-09-17 |
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US09/358,957 Expired - Fee Related US6254091B1 (en) | 1999-07-22 | 1999-07-22 | Variable cross-section vacuum grooves in an imaging system |
US09/843,050 Expired - Fee Related US6450496B2 (en) | 1999-07-22 | 2001-04-26 | Variable cross-section vacuum grooves in an external drum imaging system |
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US09/358,957 Expired - Fee Related US6254091B1 (en) | 1999-07-22 | 1999-07-22 | Variable cross-section vacuum grooves in an imaging system |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030127004A1 (en) * | 2002-01-07 | 2003-07-10 | Dainippon Screen Mfg. Co., Ltd. | Method of recording image and image recorder |
US20070126791A1 (en) * | 2005-12-02 | 2007-06-07 | Dong-Woo Ha | Inkjet image forming apparatus |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6254091B1 (en) * | 1999-07-22 | 2001-07-03 | Agfa Corporation | Variable cross-section vacuum grooves in an imaging system |
US6572095B1 (en) * | 1999-09-03 | 2003-06-03 | Fuji Photo Film Co., Ltd. | Method of and system for conveying sheet to be scanned |
EP1415804B1 (en) * | 2002-10-30 | 2008-12-24 | Heidelberger Druckmaschinen Aktiengesellschaft | Transfer cylinder for a machine processing printed sheets |
JP2006227509A (en) * | 2005-02-21 | 2006-08-31 | Fuji Photo Film Co Ltd | Inner drum type image forming apparatus |
US20080213027A1 (en) * | 2007-03-01 | 2008-09-04 | Yraceburu Robert M | Imaging device |
ITMI20131580A1 (en) * | 2013-09-25 | 2015-03-26 | Parvis Systems And Services Srl | APPARATUS FOR THE ACQUISITION OF MULTISPETTRAL IMAGES OF PRINTED SHEETS. |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS56117228A (en) * | 1980-02-21 | 1981-09-14 | Dainippon Screen Mfg Co Ltd | Film adsorbing plate for process camera |
US5099277A (en) * | 1988-12-01 | 1992-03-24 | Orren J. Lucht | Vacuum platen for use in a printer |
JPH0851143A (en) * | 1992-07-20 | 1996-02-20 | Nikon Corp | Board holding apparatus |
US5836581A (en) * | 1996-10-11 | 1998-11-17 | Barco Graphics N.V. | Device and method for loading a sheet-like medium |
US5799236A (en) * | 1997-07-31 | 1998-08-25 | Eastman Kodak Company | Facilitating duplex copying with a reproduction apparatus utilizing an intermediate transfer member |
US6051067A (en) * | 1998-04-23 | 2000-04-18 | Microjet Technology Co., Ltd. | Wafer securing device and method |
US6254091B1 (en) * | 1999-07-22 | 2001-07-03 | Agfa Corporation | Variable cross-section vacuum grooves in an imaging system |
-
1999
- 1999-07-22 US US09/358,957 patent/US6254091B1/en not_active Expired - Fee Related
-
2001
- 2001-04-26 US US09/843,050 patent/US6450496B2/en not_active Expired - Fee Related
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030127004A1 (en) * | 2002-01-07 | 2003-07-10 | Dainippon Screen Mfg. Co., Ltd. | Method of recording image and image recorder |
US7158256B2 (en) * | 2002-01-07 | 2007-01-02 | Dainippon Screen Mfg. Co., Ltd. | Method of recording image and image recorder |
US20070126791A1 (en) * | 2005-12-02 | 2007-06-07 | Dong-Woo Ha | Inkjet image forming apparatus |
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US6254091B1 (en) | 2001-07-03 |
US6450496B2 (en) | 2002-09-17 |
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