CA1106900A - Coanda effect paper transport - Google Patents
Coanda effect paper transportInfo
- Publication number
- CA1106900A CA1106900A CA287,501A CA287501A CA1106900A CA 1106900 A CA1106900 A CA 1106900A CA 287501 A CA287501 A CA 287501A CA 1106900 A CA1106900 A CA 1106900A
- Authority
- CA
- Canada
- Prior art keywords
- paper
- plate
- improvement
- copy
- transport means
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/65—Apparatus which relate to the handling of copy material
- G03G15/6529—Transporting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H29/00—Delivering or advancing articles from machines; Advancing articles to or into piles
- B65H29/24—Delivering or advancing articles from machines; Advancing articles to or into piles by air blast or suction apparatus
- B65H29/245—Air blast devices
- B65H29/248—Air blast devices with coanda effect
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Fixing For Electrophotography (AREA)
- Delivering By Means Of Belts And Rollers (AREA)
- Paper Feeding For Electrophotography (AREA)
- Advancing Webs (AREA)
- Paper (AREA)
Abstract
Abstract of the Disclosure In a document copier of the transfer type, methods and apparatus for moving copy paper from a transfer station to a fusing station through the use of the Coanda effect, i.e., the paper is transported on a moving stream of air.
The paper path between the transfer station and the fusing station is such as to cause the paper to assume an "S" shape with the paper out of direct contact with mechanical support at the curves of the "S" such that vibrational jars are absorbed in the curves of the "S."
The paper path between the transfer station and the fusing station is such as to cause the paper to assume an "S" shape with the paper out of direct contact with mechanical support at the curves of the "S" such that vibrational jars are absorbed in the curves of the "S."
Description
1~69E)~
2 This invention relates to document copier machines,
3 and more particularly to methods and apparatus which make
4 use of the Coanda effect to move copy paper from the transfer station to the fuser.
6 Background of the Invention _ 7 In document copier machines, rotating drums are 8 frequently used to support a photoreceptive material onto 9 which an e]ectrostatic image of an original document is placed. That electrostatic image is then developed by the 11 application of developing material to the image and in the 12 continued rotation of the drum that developed image is 13 transferred to receiving material, typically a sheet of copy 14 paper. After transfer of the developed image, the photorecep-tive material is cleaned and charged in order to be ready to 16 receive the next image of an original document.
17 The paper path for the copy paper begins with a 18 paper supply area which may be a paper bin holding cut 19 sheets of copy paper or a large roll of paper which is cut as it is unwound. In either case, the sheet of copy paper 21 is fed from the supply area to the transfer station and 22 placed in direct contact with the developed image. A corona 23 is provided which attracts the developing material from the 24 drum to the paper so that when the paper is stripped from contact with the drum, the image remains on the paper. The 26 paper is then transported to a fusing apparatus which, 27 through application of heat, joins the developer material to 28 the paper. Developing materials in current use include 9~0 1 toner powders which rest on the copy paper after transfer 2 and can be easily dislodged before fusing with resultant 3 destruction of the image with the slightest jar of the copy 4 paper or physical contact with the unfused side of the paper. As a consequence, one of the problems of document 6 copier machines is to provide a mechanism for transporting 7 the copy paper with the developed image thereon from the 8 transfer station to a fusing station without jarring the 9 copy paper or physically contacting the side of the paper with the developed image.
11 Prior art apparatus devised for transporting copy 12 paper with unfused images have typically included the vacuum 13 transport, i.e., an endless belt moving across a plenum to 14 which the paper is attracted by a vacuum. Other means have included the electrostatic attraction available between a 16 metal plenum and a sheet of copy paper and currently there 17 is some experimentation with the use of starwheels which 18 direct the copy paper toward the fuser by acting on the 19 unfused but developed side of the copy paper. All of the above techniques have disadvantages relating to cost, size, 21 contamination of the copy sheet, or reliability. The 22 current invention, therefore, has as a primary object the 23 provision of a paper transport for unfused copy paper which 24 is reliable, compact, and economical.
It is a further object of this invention to provide 26 apparatus for transporting paper in which vibrational jarring 27 is kept to a minimum through the use of air cushions as 28 shock absorbers for the paper.
29 In a compact document copier machine utilizing a hot roll fuser, a copy quality problem develops where the ~1~6~00 1 trailing edge of the copy paper is still in the process of 2 receiving an image in a transfer station when the leading 3 edge of the copy paper enters the nip of the hot roll fuser.
4 The problem appears as a mark on the copy paper since, when the leading edge enters the hot roll fuser, a jar is trans-6 mitted down the paper from the leading edge to the transfer 7 station and causes a smearing of the image at that point.
8 It is, therefore, another primary object of this invention to 9 eliminate such a mark by providin~ a paper transport which absorbs the vibrational jars of entering the nip of a hot 11 fuser prior to the transmission of that jar to the transfer 12 station.
13 Summary of the Invention 14 This invention involves the use of the Coanda effect, i.e., that moving air adheres to a smooth surface 16 and tends to follow the contour of that surface to provide a 17 transport which accomplishes the above-stated objects.
18 - In a first preferred embodiment of the invention, 19 air is blown along a deflector plate such that the developed but unfused side of the copy paper is carried toward the nip 21 of a hot roll fuser along an air cushion which follows the 22 contour of the deflector. The deflector is positioned such 23 that the paper assumes an "S" shape for absorbing jars upon 24 fuser entrance.
In a second preferred embodiment of the invention, 26 air is blown along a smooth surfaced transport leaving a low 27 pressure area in and near the airstream, causing the under-28 side of the paper to adhere to the airstream and follow the 6~00 1 surface contour of the transport from the transfer station 2 to the hot roll fuser. The contour takes an "S" shape for 3 absorbing jars upon fuser entrance.
4 Brief Description of the Drawin~s The above-mentioned and other features and objects 6 of this invention and the manner of attaining them will 7 become more apparent and the invention itself will best be 8 understood by reference to the following description of 9 embodiments of the invention taken in conjunction with the accompanying drawings, the description of which follows.
11 FIGURE 1 is a perspective view of the paper path 12 of a document copier machine incorporating one embodiment of 13 the instant invention.
14 FIGURE 2 is a planar view showing one embodiment lS of the instant invention.
16 FIG~E 3 is a planar view showing another embodi-17 ment of the instant invention.
18 Detailed Description 19 FIGURE 1 shows the paper path of a typical document copier such as that described above under background of the 21 invention, showing a drum 10, a developer 11, a transfer 22 station 12 with its associated corona 13, a charging corona 23 14, and a preclean corona 15. The drum 10 rotates in the 24 direction A and carries a photoreceptive material thereon which receives an electrostatic charge from the corona 14.
26 An image of an original document is placed on the charged 27 photoreceptive material by apparatus not shown prior to the 28 arrival of the photoreceptive material at the developer 11.
Bo976030 ~4~
11~6900 1 The developer deposits developing material such as a powder 2 on the surface of the photoreceptor to develop the electro-3 static image thereon. The continued rotation of the drum 10 4 in the direction A carries the developed electrostatic image to the transfer station 12 where the image is mated with a 6 copy paper 17, and the developing material is transferred to 7 the copy paper 17 under the influence of an electrostatic 8 field generated by the corona 13. The continued rotation of 9 the drum carries the photoreceptive material through a preclean corona 15 and a cleaning station which may be 1l combined with the developer 11. In that manner the photorec-12 eptive material is made ready for the application of the 13 next image. FIGURE 1 shows a compact document copier machine 14 in which the copy paper 17 is receiving a developed image at transfer station 12, while at the same time the developed 16 image is being fused to the copy paper 17 in the nip of the 17 fuser rolls 18 and 19, wherein the hot roll is 18 and the 18 backup roll is the roll l9.
19 One embodiment of this invention is shown in FIGURE 1 for transporting the paper from the transfer station 21 12 to the fuser rolls 18 and 19. In this case a deflector 22 plate 20 is positioned as shown and air is blown over the 23 deflector by the fan 21. The moving surface of air provides 24 an air cushion to guide the paper along the deflector into the nip of the fuser rolls. Guide 20a acts on the underside 26 of the paper to prevent a deflection of the paper downwardly 27 into backup roll 19. This embodiment of the invention will 28 be explained further with respect to FIGURE 2.
29 In FIGURE 2 the drum 10 is shown with transfer station 12. Copy paper 17 is shown with the trailing edge g~O
1 extending just beyond transfer station 12 and the leading 2 edge far beyond the fuser rolls 18 and 19 just entering a 3 pair of pinch rolls 22 and 23, A mechanical sheet stripplng 4 finger 24 is shown in its rest position and in phantom in the position it takes before the leading edge of the copy 6 paper 17 strikes it. The finger 24 is positioned against or 7 closely adjacent to drum 10 in the position shown in phantom 8 so that as the leading edge of the copy paper 17 leaves g transfer station 12, it is captured in the notch 25 of finger 24, and thus drives the finger back around its pivot 11 32. In that manner the leading edge of the paper is stripped 12 away from drum 10 and pushes finger 24 in an arcuate path to 13 a position shown approximately at 26. At that point the 14 finger 24 is accelerated away from the leading edge of the copy paper, for example, by an overcenter spring, not shown, 16 and the guidance of the leading edge of the copy paper is 17 taken over by the influence of an airstream shown by dotted 18 lines adjacent to the deflector plate 20. As discussed 19 above, this airstream moves along the surface of the deflector plate 20 according to the Coanda effect and guides the paper ?.1 17 while keeping that paper apart from contact with the 22 deflector 20. In actuality, the air acts as a bearing or 23 cushion to guide the paper along the deflector surface but 24 does not allow the paper to come into contact with the deflector surface. In that manner, the leading edge of the 26 copy paper is guided by the deflector 20 and the associated 27 airstream into the nip of the rollers 18 and 19. The 28 actual path of the leading edge of the paper may be guided 9~ ' 1 by guide 20a to strike the backup roller 19 just ahead of 2 entrance into the nip of the rollers, so as to form a gentle 3 curve in the paper as part of an "S" shape. It is the 4 entrance into the nip of the rollers 18 and 19 which can create a mark on the paper at transfer station 12 by virtue 6 of the driving effect on the paper which takes place when 7 the rollers 18 and 19 grasp the paper and begin to move it.
8 Any jarring effect of that entrance into the nip is dissipated 9 in the curves of an "S" shape in the length of the copy paper between the nip of the fuser rolls and transfer station 11 12 due to the fact that the paper is at no point solidly 12 attached to any transport mechanism. The "S" shape is 13 formed in the paper by properly positioning the deflector 14 ~ 20.
1~ FIGURE 3 shows another embodiment of the invention wherein the plate over which air is blown is placed on the 17 underside of the copy paper rather than on the toned but 18 unfused side as shown in FIGURE 2. In FIGURE 3 the copy 19 paper 17 once again is positioned with the trailing edge still to reach transfer station 12 but with the leading edge 21 already beyond the fusing rolls 18 and 19 and entering pinch 22 rolls 22 and 23. A sheet stripping finger 24 is provided 23 and operates, as discussed above, to strip the copy paper 24 from the drum 10 and guide that paper in an arcuate path into proximity with the airstream. At that point the finger 26 24 is accelerated away from the leading edge of the paper 27 and the paper is held to the airstream by forces produced in ,~8 accordance with the Bernoulli principle, and carried by the 29 airstream along the surface of the plate 20 into the nip of Bo976030 ~7-V
1 the fuser rolls. Note that in this embodiment of the inven-2 tion, the deflector plate 20 imparts an "S" shape to the copy 3 paper so that when the leading edge of the paper enters the 4 nip of the fuser rolls any shock from that entrance is dissipated in the bends of the "S" and does not reach backward 6 to the transfer station 12.
7 In both FIGURES 2 and 3 a centrifugal fan or 8 centrifugal blower 21 is shown feeding a plenum 30. A tube o 31 extends out of the plenum 30 to carry the airflow to the deflector plate 20. In referring to FIGURE 1 it can be seen 11 that the plenum 30 and the tube 31 extend across the width 12 of the paper such that a uniform distribution of airflow is 13 present from one side of the paper path to the other.
14 An interesting aspect of the Coanda effect phenom-enon is that by virtue of the moving airstream a low pressure 16 area is present in and near the airstream such that the 17 paper "adheres" to the airstream by virtue of the Bernoulli 18 principle. Thus, the transport of this invention takes 19 advantage of both the Coanda effect and the Bernoulli princi-ple to move paper across the surface of the deflector without 21 contacting it. Very small air pressures are suitable, for 22 example, as low as 0.04 inches water pressure appears adequate 23 but optimally over 0.08 inches. These low air pressures ~4 correspond approximately to a minimum required airstream velocity of 50 inches-per-second. The thickness of the air-26 stream is a function of the width of the tube 31 and it has 27 been found that if the thickness of the airstream drops 28 under 0.05 inches there will be insufficient viscous forces 29 to the airstream to keep the paper out of contact with the deflector plate. Similarly, if the width of the airstream 369~0 1 is increased above 0.25 inches the internal viscous forces 2 weaken and the airstrea~ does not follow the plate, i.e,, 3 the Coanda effect breaks down, Thus, it appears that the 4 best range of values is betweqn those two extremes and optimally somewhat less than 0.15 inches thick.
6 While the invention has been particularly shown 7 and described with reference to a preferred embodiment 8 thereof, it will be understood by those skilled in the art 9 that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope 11 of the invention.
BO9?6030 -9-
6 Background of the Invention _ 7 In document copier machines, rotating drums are 8 frequently used to support a photoreceptive material onto 9 which an e]ectrostatic image of an original document is placed. That electrostatic image is then developed by the 11 application of developing material to the image and in the 12 continued rotation of the drum that developed image is 13 transferred to receiving material, typically a sheet of copy 14 paper. After transfer of the developed image, the photorecep-tive material is cleaned and charged in order to be ready to 16 receive the next image of an original document.
17 The paper path for the copy paper begins with a 18 paper supply area which may be a paper bin holding cut 19 sheets of copy paper or a large roll of paper which is cut as it is unwound. In either case, the sheet of copy paper 21 is fed from the supply area to the transfer station and 22 placed in direct contact with the developed image. A corona 23 is provided which attracts the developing material from the 24 drum to the paper so that when the paper is stripped from contact with the drum, the image remains on the paper. The 26 paper is then transported to a fusing apparatus which, 27 through application of heat, joins the developer material to 28 the paper. Developing materials in current use include 9~0 1 toner powders which rest on the copy paper after transfer 2 and can be easily dislodged before fusing with resultant 3 destruction of the image with the slightest jar of the copy 4 paper or physical contact with the unfused side of the paper. As a consequence, one of the problems of document 6 copier machines is to provide a mechanism for transporting 7 the copy paper with the developed image thereon from the 8 transfer station to a fusing station without jarring the 9 copy paper or physically contacting the side of the paper with the developed image.
11 Prior art apparatus devised for transporting copy 12 paper with unfused images have typically included the vacuum 13 transport, i.e., an endless belt moving across a plenum to 14 which the paper is attracted by a vacuum. Other means have included the electrostatic attraction available between a 16 metal plenum and a sheet of copy paper and currently there 17 is some experimentation with the use of starwheels which 18 direct the copy paper toward the fuser by acting on the 19 unfused but developed side of the copy paper. All of the above techniques have disadvantages relating to cost, size, 21 contamination of the copy sheet, or reliability. The 22 current invention, therefore, has as a primary object the 23 provision of a paper transport for unfused copy paper which 24 is reliable, compact, and economical.
It is a further object of this invention to provide 26 apparatus for transporting paper in which vibrational jarring 27 is kept to a minimum through the use of air cushions as 28 shock absorbers for the paper.
29 In a compact document copier machine utilizing a hot roll fuser, a copy quality problem develops where the ~1~6~00 1 trailing edge of the copy paper is still in the process of 2 receiving an image in a transfer station when the leading 3 edge of the copy paper enters the nip of the hot roll fuser.
4 The problem appears as a mark on the copy paper since, when the leading edge enters the hot roll fuser, a jar is trans-6 mitted down the paper from the leading edge to the transfer 7 station and causes a smearing of the image at that point.
8 It is, therefore, another primary object of this invention to 9 eliminate such a mark by providin~ a paper transport which absorbs the vibrational jars of entering the nip of a hot 11 fuser prior to the transmission of that jar to the transfer 12 station.
13 Summary of the Invention 14 This invention involves the use of the Coanda effect, i.e., that moving air adheres to a smooth surface 16 and tends to follow the contour of that surface to provide a 17 transport which accomplishes the above-stated objects.
18 - In a first preferred embodiment of the invention, 19 air is blown along a deflector plate such that the developed but unfused side of the copy paper is carried toward the nip 21 of a hot roll fuser along an air cushion which follows the 22 contour of the deflector. The deflector is positioned such 23 that the paper assumes an "S" shape for absorbing jars upon 24 fuser entrance.
In a second preferred embodiment of the invention, 26 air is blown along a smooth surfaced transport leaving a low 27 pressure area in and near the airstream, causing the under-28 side of the paper to adhere to the airstream and follow the 6~00 1 surface contour of the transport from the transfer station 2 to the hot roll fuser. The contour takes an "S" shape for 3 absorbing jars upon fuser entrance.
4 Brief Description of the Drawin~s The above-mentioned and other features and objects 6 of this invention and the manner of attaining them will 7 become more apparent and the invention itself will best be 8 understood by reference to the following description of 9 embodiments of the invention taken in conjunction with the accompanying drawings, the description of which follows.
11 FIGURE 1 is a perspective view of the paper path 12 of a document copier machine incorporating one embodiment of 13 the instant invention.
14 FIGURE 2 is a planar view showing one embodiment lS of the instant invention.
16 FIG~E 3 is a planar view showing another embodi-17 ment of the instant invention.
18 Detailed Description 19 FIGURE 1 shows the paper path of a typical document copier such as that described above under background of the 21 invention, showing a drum 10, a developer 11, a transfer 22 station 12 with its associated corona 13, a charging corona 23 14, and a preclean corona 15. The drum 10 rotates in the 24 direction A and carries a photoreceptive material thereon which receives an electrostatic charge from the corona 14.
26 An image of an original document is placed on the charged 27 photoreceptive material by apparatus not shown prior to the 28 arrival of the photoreceptive material at the developer 11.
Bo976030 ~4~
11~6900 1 The developer deposits developing material such as a powder 2 on the surface of the photoreceptor to develop the electro-3 static image thereon. The continued rotation of the drum 10 4 in the direction A carries the developed electrostatic image to the transfer station 12 where the image is mated with a 6 copy paper 17, and the developing material is transferred to 7 the copy paper 17 under the influence of an electrostatic 8 field generated by the corona 13. The continued rotation of 9 the drum carries the photoreceptive material through a preclean corona 15 and a cleaning station which may be 1l combined with the developer 11. In that manner the photorec-12 eptive material is made ready for the application of the 13 next image. FIGURE 1 shows a compact document copier machine 14 in which the copy paper 17 is receiving a developed image at transfer station 12, while at the same time the developed 16 image is being fused to the copy paper 17 in the nip of the 17 fuser rolls 18 and 19, wherein the hot roll is 18 and the 18 backup roll is the roll l9.
19 One embodiment of this invention is shown in FIGURE 1 for transporting the paper from the transfer station 21 12 to the fuser rolls 18 and 19. In this case a deflector 22 plate 20 is positioned as shown and air is blown over the 23 deflector by the fan 21. The moving surface of air provides 24 an air cushion to guide the paper along the deflector into the nip of the fuser rolls. Guide 20a acts on the underside 26 of the paper to prevent a deflection of the paper downwardly 27 into backup roll 19. This embodiment of the invention will 28 be explained further with respect to FIGURE 2.
29 In FIGURE 2 the drum 10 is shown with transfer station 12. Copy paper 17 is shown with the trailing edge g~O
1 extending just beyond transfer station 12 and the leading 2 edge far beyond the fuser rolls 18 and 19 just entering a 3 pair of pinch rolls 22 and 23, A mechanical sheet stripplng 4 finger 24 is shown in its rest position and in phantom in the position it takes before the leading edge of the copy 6 paper 17 strikes it. The finger 24 is positioned against or 7 closely adjacent to drum 10 in the position shown in phantom 8 so that as the leading edge of the copy paper 17 leaves g transfer station 12, it is captured in the notch 25 of finger 24, and thus drives the finger back around its pivot 11 32. In that manner the leading edge of the paper is stripped 12 away from drum 10 and pushes finger 24 in an arcuate path to 13 a position shown approximately at 26. At that point the 14 finger 24 is accelerated away from the leading edge of the copy paper, for example, by an overcenter spring, not shown, 16 and the guidance of the leading edge of the copy paper is 17 taken over by the influence of an airstream shown by dotted 18 lines adjacent to the deflector plate 20. As discussed 19 above, this airstream moves along the surface of the deflector plate 20 according to the Coanda effect and guides the paper ?.1 17 while keeping that paper apart from contact with the 22 deflector 20. In actuality, the air acts as a bearing or 23 cushion to guide the paper along the deflector surface but 24 does not allow the paper to come into contact with the deflector surface. In that manner, the leading edge of the 26 copy paper is guided by the deflector 20 and the associated 27 airstream into the nip of the rollers 18 and 19. The 28 actual path of the leading edge of the paper may be guided 9~ ' 1 by guide 20a to strike the backup roller 19 just ahead of 2 entrance into the nip of the rollers, so as to form a gentle 3 curve in the paper as part of an "S" shape. It is the 4 entrance into the nip of the rollers 18 and 19 which can create a mark on the paper at transfer station 12 by virtue 6 of the driving effect on the paper which takes place when 7 the rollers 18 and 19 grasp the paper and begin to move it.
8 Any jarring effect of that entrance into the nip is dissipated 9 in the curves of an "S" shape in the length of the copy paper between the nip of the fuser rolls and transfer station 11 12 due to the fact that the paper is at no point solidly 12 attached to any transport mechanism. The "S" shape is 13 formed in the paper by properly positioning the deflector 14 ~ 20.
1~ FIGURE 3 shows another embodiment of the invention wherein the plate over which air is blown is placed on the 17 underside of the copy paper rather than on the toned but 18 unfused side as shown in FIGURE 2. In FIGURE 3 the copy 19 paper 17 once again is positioned with the trailing edge still to reach transfer station 12 but with the leading edge 21 already beyond the fusing rolls 18 and 19 and entering pinch 22 rolls 22 and 23. A sheet stripping finger 24 is provided 23 and operates, as discussed above, to strip the copy paper 24 from the drum 10 and guide that paper in an arcuate path into proximity with the airstream. At that point the finger 26 24 is accelerated away from the leading edge of the paper 27 and the paper is held to the airstream by forces produced in ,~8 accordance with the Bernoulli principle, and carried by the 29 airstream along the surface of the plate 20 into the nip of Bo976030 ~7-V
1 the fuser rolls. Note that in this embodiment of the inven-2 tion, the deflector plate 20 imparts an "S" shape to the copy 3 paper so that when the leading edge of the paper enters the 4 nip of the fuser rolls any shock from that entrance is dissipated in the bends of the "S" and does not reach backward 6 to the transfer station 12.
7 In both FIGURES 2 and 3 a centrifugal fan or 8 centrifugal blower 21 is shown feeding a plenum 30. A tube o 31 extends out of the plenum 30 to carry the airflow to the deflector plate 20. In referring to FIGURE 1 it can be seen 11 that the plenum 30 and the tube 31 extend across the width 12 of the paper such that a uniform distribution of airflow is 13 present from one side of the paper path to the other.
14 An interesting aspect of the Coanda effect phenom-enon is that by virtue of the moving airstream a low pressure 16 area is present in and near the airstream such that the 17 paper "adheres" to the airstream by virtue of the Bernoulli 18 principle. Thus, the transport of this invention takes 19 advantage of both the Coanda effect and the Bernoulli princi-ple to move paper across the surface of the deflector without 21 contacting it. Very small air pressures are suitable, for 22 example, as low as 0.04 inches water pressure appears adequate 23 but optimally over 0.08 inches. These low air pressures ~4 correspond approximately to a minimum required airstream velocity of 50 inches-per-second. The thickness of the air-26 stream is a function of the width of the tube 31 and it has 27 been found that if the thickness of the airstream drops 28 under 0.05 inches there will be insufficient viscous forces 29 to the airstream to keep the paper out of contact with the deflector plate. Similarly, if the width of the airstream 369~0 1 is increased above 0.25 inches the internal viscous forces 2 weaken and the airstrea~ does not follow the plate, i.e,, 3 the Coanda effect breaks down, Thus, it appears that the 4 best range of values is betweqn those two extremes and optimally somewhat less than 0.15 inches thick.
6 While the invention has been particularly shown 7 and described with reference to a preferred embodiment 8 thereof, it will be understood by those skilled in the art 9 that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope 11 of the invention.
BO9?6030 -9-
Claims (27)
1. In a document copier machine of the transfer type, apparatus for moving copy paper from a paper supply area to a transfer station, whereat a developed electrostatic image is transferred to said copy paper and thereafter said copy paper is moved to a fusing station, the improvement comprising:
a source for pressurizing gaseous fluid;
a paper transport means for defining a path along which said paper is moved from said transfer station to said fusing station; and an outlet means connected to said source means and positioned along the surface of said transport means for releasing said gaseous fluid in a flow across the surface of said transport means according to the Coanda effect, whereby said paper is transported across the surface of said transport means on a cushion of said gaseous fluid.
a source for pressurizing gaseous fluid;
a paper transport means for defining a path along which said paper is moved from said transfer station to said fusing station; and an outlet means connected to said source means and positioned along the surface of said transport means for releasing said gaseous fluid in a flow across the surface of said transport means according to the Coanda effect, whereby said paper is transported across the surface of said transport means on a cushion of said gaseous fluid.
2. The improvement of Claim 1 wherein said transport means comprises a plate positioned above the paper path and said paper rides across the undersurface of said plate.
3. The improvement of Claim 2 wherein said plate defines a paper path such that said copy paper assumes an "S" shape between said transfer station and said fusing station.
4. The improvement of Claim 2 wherein the paper surface directly adjacent said plate carries the developed but unfused image.
5. The improvement of Claim 4 wherein said gaseous fluid is released from said outlet in a stream along the surface of said plate in a thickness range of 0.05 to 0.25 inches.
6. The improvement of Claim 1 wherein said transport means comprises a plate positioned below the paper path and said paper rides across the top surface of said plate.
7. The improvement of Claim 6 wherein said plate defines a paper path such that said copy paper assumes an "S" shape between said transfer station and said fusing station.
8. The improvement of Claim 6 wherein the paper surface not directly adjacent said plate carries the developed but unfused image.
9. The improvement of Claim 8 wherein said gaseous fluid is released from said outlet in a stream along the surface of said plate in a thickness range of 0.05 to 0.25 inches.
10. In a document copier machine of the transfer type, the method of moving paper comprising the steps of:
moving sheets of copy paper one at a time from a paper supply area to a transfer area;
transferring a developed electrostatic image to said paper;
stripping said paper from said transfer area; and transporting said paper to a fusing station, across a trans-port means along the surface of which gaseous fluid is made to flow according to the Coanda effect.
moving sheets of copy paper one at a time from a paper supply area to a transfer area;
transferring a developed electrostatic image to said paper;
stripping said paper from said transfer area; and transporting said paper to a fusing station, across a trans-port means along the surface of which gaseous fluid is made to flow according to the Coanda effect.
11. The method of Claim 10 wherein said transport means comprises a plate which is positioned above the paper path and said paper rides across the undersurface of said plate according to the Bernoulli principle.
12. The method of Claim 10 wherein the steps of transporting said paper includes placing the side of said copy paper carrying the developed but unfused image directly adjacent the surface of said transport means.
13. The method of Claim 10 wherein said gaseous fluid is released along the surface of said transport means in a thickness range of 0.05 to 0.25 inches.
14. In a document copier machine of the transfer type, the method of moving paper comprising the steps of:
moving sheets of copy paper one at a time from a paper supply area to a transfer area;
transferring a developed electrostatic image to said paper;
stripping said paper from said transfer area; and transporting said paper to a fusing station across a transport means (along the surface of which gaseous fluid is made to flow according to the Coanda effect) which de-fines a paper path, said transporting step including the step of placing an "S" shape in said copy paper between said transfer station and said fusing station.
moving sheets of copy paper one at a time from a paper supply area to a transfer area;
transferring a developed electrostatic image to said paper;
stripping said paper from said transfer area; and transporting said paper to a fusing station across a transport means (along the surface of which gaseous fluid is made to flow according to the Coanda effect) which de-fines a paper path, said transporting step including the step of placing an "S" shape in said copy paper between said transfer station and said fusing station.
15. The method of Claim 14 wherein said copy paper is unsupported by direct contact with mechanical means in the curves of said "S" shape, whereby any vibrational jars occurring in said paper are substantially absorbed in said curves.
16. The method of Claim 15 wherein said transport means comprises a plate and said step of transporting paper further includes the steps of:
blowing gaseous fluid across the surface of said plate according to the Coanda effect; and positioning said plate above said path such that said paper rides across the undersurface of said plate according to the Bernoulli principle.
blowing gaseous fluid across the surface of said plate according to the Coanda effect; and positioning said plate above said path such that said paper rides across the undersurface of said plate according to the Bernoulli principle.
17. The method of Claim 16 wherein the transport-ing step includes placing the side of said paper carrying the developed but unfused image directly adjacent the surface of said transport means.
18. The method of Claim 15 wherein said transport means comprises a plate and said step of transporting paper further includes the steps of:
blowing gaseous fluid across the surface of said plate according to the Coanda effect; and positioning said plate below said path such that said paper rides across the top surface of said plate.
blowing gaseous fluid across the surface of said plate according to the Coanda effect; and positioning said plate below said path such that said paper rides across the top surface of said plate.
19. A document copier machine wherein an image is transferred to a sheet of copy paper comprising:
a paper supply area for holding copy paper;
a transfer station for transferring a powder image to said copy paper;
apparatus for moving copy paper from said paper supply area to said transfer station;
a fusing station for fusing said powder image to said copy paper;
a paper transport means containing a surface positioned between said transfer station and said fusing station for defining at least part of a path for said copy paper to follow;
a source means for pressurizing gaseous fluid;
a Coanda effect producing means connected to said source means for producing a Coanda effect fluid flow across said surface means between said transfer station and said fusing station for transporting said paper across said surface on a fluidic cushion such that the unfused powder image is not destroyed; and a guiding means to guide said copy paper from said transfer station to said flow across said surface.
a paper supply area for holding copy paper;
a transfer station for transferring a powder image to said copy paper;
apparatus for moving copy paper from said paper supply area to said transfer station;
a fusing station for fusing said powder image to said copy paper;
a paper transport means containing a surface positioned between said transfer station and said fusing station for defining at least part of a path for said copy paper to follow;
a source means for pressurizing gaseous fluid;
a Coanda effect producing means connected to said source means for producing a Coanda effect fluid flow across said surface means between said transfer station and said fusing station for transporting said paper across said surface on a fluidic cushion such that the unfused powder image is not destroyed; and a guiding means to guide said copy paper from said transfer station to said flow across said surface.
20. The improvement of Claim 19 wherein said transport means comprises a plate positioned above the paper path and said paper rides across the undersurface of said plate.
21. The improvement of Claim 20 wherein said plate defines a paper path such that said copy paper assumes an "S"
shape between said transfer station and said fusing station.
shape between said transfer station and said fusing station.
22. The improvement of Claim 20 wherein the paper surface directly adjacent said plate carries the developed but unfused image.
23. The improvement of Claim 22 wherein said gaseous fluid is released from said outlet in a stream along the surface of said plate in a thickness range of 0.05 to 0.25 inches.
24. The improvement of Claim 19 wherein said transport means comprises a plate positioned below the paper path and said paper rides across the top surface of said plate.
25. The improvement of Claim 24 wherein said plate defines a paper path such that said copy paper assumes an "S"
shape between said transfer station and said fusing station.
shape between said transfer station and said fusing station.
26. The improvement of Claim 24 wherein the paper surface not directly adjacent said plate carries the developed but unfused image.
27. The improvement of Claim 26 wherein said gaseous fluid is released from said outlet in a stream along the surface of said plate in a thickness range of 0.05 to 0.25 inches.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US74302676A | 1976-11-18 | 1976-11-18 | |
| US743,026 | 1976-11-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1106900A true CA1106900A (en) | 1981-08-11 |
Family
ID=24987224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA287,501A Expired CA1106900A (en) | 1976-11-18 | 1977-09-26 | Coanda effect paper transport |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5364041A (en) |
| AU (1) | AU516348B2 (en) |
| CA (1) | CA1106900A (en) |
| DE (1) | DE2744959A1 (en) |
| FR (1) | FR2371369A1 (en) |
| GB (1) | GB1564859A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11407605B2 (en) | 2019-12-05 | 2022-08-09 | Xerox Corporation | Air-based photoreceptor sheet stripper |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3054613A (en) * | 1960-12-28 | 1962-09-18 | Warren S D Co | Sheet delivery system |
| US3276425A (en) * | 1963-09-05 | 1966-10-04 | Addressograph Multigraph | Copying machine |
| US3236517A (en) * | 1965-03-23 | 1966-02-22 | Lyman Brooks | Sheet handling apparatus |
| US3784190A (en) * | 1971-12-27 | 1974-01-08 | Ibm | Sheet removing apparatus |
| DE2501487C2 (en) * | 1975-01-16 | 1976-10-07 | Hoechst Ag | REMOVAL DEVICE FOR A SHEET-SHAPED COPY CARRIER |
| DE2714679C2 (en) * | 1976-04-29 | 1986-12-18 | Xerox Corp., Rochester, N.Y. | Guide device for copy sheets in an electrographic copier |
-
1977
- 1977-09-13 GB GB3815077A patent/GB1564859A/en not_active Expired
- 1977-09-26 CA CA287,501A patent/CA1106900A/en not_active Expired
- 1977-10-06 DE DE19772744959 patent/DE2744959A1/en not_active Withdrawn
- 1977-10-06 AU AU29428/77A patent/AU516348B2/en not_active Expired
- 1977-10-07 FR FR7731529A patent/FR2371369A1/en active Granted
- 1977-10-14 JP JP12258877A patent/JPS5364041A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE2744959A1 (en) | 1978-05-24 |
| JPS5364041A (en) | 1978-06-08 |
| GB1564859A (en) | 1980-04-16 |
| AU516348B2 (en) | 1981-05-28 |
| JPS6143710B2 (en) | 1986-09-29 |
| FR2371369B1 (en) | 1980-08-08 |
| AU2942877A (en) | 1979-04-12 |
| FR2371369A1 (en) | 1978-06-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |