Film centering device
A sheet centering device for centering at least first and second sized sheets comprising: a base member having a surface along which a sheet is transported along a sheet transport path; a skew roller mounted on the base member at an angle to the sheet transport path; a first sheet guide mounted on the base member along one side thereof; a second sheet guide mounted on the base member parallel to but inwardly of the first sheet guide; and a drive assembly for moving the second sheet guide between a position out of the sheet transport path when a first sized sheet is transported along the sheet transport path and a position in the sheet transport path when a second sized sheet smaller than the first sized sheet is transported along the sheet transport path.
This invention relates in general to sheet handling systems and more particularly to the centering of sheets used in image reproduction apparatus.
BACKGROUND OF THE INVENTIONImage reproduction apparatus, such as electrographic, ink jet and laser printers, use media sheet such as paper or film to produce copies of images such as medical images. Typically, the media sheet needs to be correctly positioned in the apparatus with respect to the printing system. Methods for positioning the media sheet include positioning the media sheet so that one edge of the sheet is positioned against a reference surface located at one end of the printing system and positioning the sheet such that the center of the sheet comes in the center of the printing system. One technique for carrying out the latter method is to provide members on both sides of the sheet transport path to center the sheet in the apparatus. This technique is relatively complex and inefficient. A technique for carrying out the former method is disclosed in U.S. Pat. No. 4,982,946, issued Jan. 8, 1991, inventors Uchimura et al. As disclosed, a skew roller arranged at an angle to the transport direction of a paper sheet positions an edge of the paper sheet against a fixed reference guide running parallel to the transport direction.
There is no disclosure in this patent of applying this technique for different widths of sheet. If different widths of sheet are positioned against the fixed guide, they are edge justified and the centerline of the sheet would not pass through the centerline of the apparatus.
There is thus a need in reproduction apparatus for a simple and efficient technique for centering different size sheets in the apparatus.
SUMMARY OF THE INVENTIONAccording to the present invention, there is provided a solution to these needs and problems.
According to a feature of the present invention, there is provided a sheet centering device for centering at least first and second sized sheets comprising:
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- a base member having a surface along which a sheet is transported along a sheet transport path;
- a skew roller mounted on said base member at an angle to said sheet transport path;
- a first sheet guide mounted on said base member along one side thereof;
- a second sheet guide mounted on said base member parallel to but inwardly of said first sheet guide; and
- a drive assembly for moving said second sheet guide between a position out of said sheet transport path when a first sized sheet is transported along said sheet transport path and a position in said sheet transport path when a second sized sheet smaller than said first sized sheet is transported along said sheet transport path.
The invention has the following advantages.
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- 1. Different widths of media sheet can be positioned in reproduction apparatus such that they are transported along the centerline of the apparatus.
- 2. As opposed to a mechanism that uses guides on both sides of the sheet to center the sheet, the invention is relatively simple and reliable.
- 3. The same roller assembly is used to center the sheet and transport the sheet into the printing system transport rollers.
- 4. The centering of the sheet to a known position is constant.
Referring now to
A film pick-up device feeds a sheet of unexposed film from module 104 along a sheet transport path 112. The unexposed film is transported along path 112 from film pick up position 114 to transport rollers 116 at position 118, where it enters the sheet centering device 120 of the present invention. Device 120 includes skew roller 122 at position 124 at which the film is positioned by skew roller 122 against a film guide. The centered film is transported to imaging position 126 including rollers 5 and 6 where the film is exposed to a medical image by optics module 106. The film is transported past positions 132, 134 by transport rollers 136, 138 respectively to image processor 108, at position 139. Processor 108 heat processes the exposed film to produce a developed medical image on the film. The film is transported along path 112 out of processor 108 to output tray 110.
Referring now to
Operation of device 120 in apparatus 100 is as follows:
For a large sheet of film: The sheet is directed towards a fixed guide 2 and the skew roller 1 is rotated via means of a motor assembly 3. The film is pushed towards and into the edge guide 2 and then slides along the edge guide towards the imaging nip 5, 6. As shown in
For a small sheet of film: The lift motor assembly 7 is engaged which rotates a shaft/cam assembly 11. (
After imaging a small film sheet, the device can either be left in position or lowered back into it's home position to allow a large film sheet to be imaged. To lower the small film guide 9 back below the base plate, the lift motor assembly 7 is engaged which rotates a shaft/cam assembly 11. The cams on the shaft are located directly under the small film guide 9 and as they are rotated the small film guide 9 is pushed below the base plate by the springs 8 as the cam assembly 11 retreats. (
The machine would know what size film sheet is loaded by reading the information on the film cartridge after it is inserted into the machine. It would then correctly position the small edge guide into the up or down position.
Because centering of the film to a known position is constant, a smaller border region on the film print as allowed. Furthermore, the offset can be measured during manufacturing and an offset can be added to the machine electronics to allow no border if desired.
Although a fixed large film guide has been described, it will be understood that a large film guide which is movable into and out of the film path may also be provided. Furthermore, more than two film sizes can be accommodated with the addition of other film guides movable into and out of the film path.
Another embodiment of this device would be to have the skew roller assembly 122 rotate. That is, the drive angle of the roller in regards to the sheet could also be varied as different width sheets are passed through the system. The angle setting would be dependent on what size cartridge is loaded in device 104. Similarly it reads the information off of the cartridge. The advantage of this would be a smoother rotation of the sheet and push into the nip rollers.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Parts List
- 1 skew roller
- 2 large film guide
- 3 skew roller drive motor
- 4 drive motor assembly
- 5,6 rollers
- 7 lift drive motor assembly
- 8 lift springs
- 9 small film guide
- 10 drive motor pulley
- 11 cam
- 12 belt
- 32 film direction
- 34 base plate
- 36,38 brackets
- 100 apparatus
- 102 housing
- 104 module
- 106 optics module
- 108 film processor module
- 110 output tray
- 112 sheet transport path
- 114 film up position
- 116 transport rollers
- 118 position
- 120 sheet centering device
- 122 skew roller
- 124 position
- 1226 imaging position
- 132,134 positions
- 136,138 transport rollers
- 139 position
- 200 film
Claims
1. A sheet centering device for centering at least first and second sized sheets comprising:
- a base member having a surface along which a sheet is transported along a sheet transport path;
- a skew roller mounted on said base member at an angle to said sheet transport path;
- a first sheet guide mounted on said base member along one side thereof,
- a second sheet guide mounted on said base member parallel to but inwardly of said first sheet guide; and
- a drive assembly for moving said second sheet guide between a position out of said sheet transport path when a first sized sheet is transported along said sheet transport path and a position in said sheet transport path when a second sized sheet smaller than said first sized sheet is transported along said sheet transport path.
2. The sheet centering device of claim 1 wherein said first sheet guide is fixedly mounted on said base member.
3. The sheet centering device of claim 1 wherein said first sheet guide is mounted on said base member for movement between an up position in said sheet transport path and a down position out of said sheet transport path.
4. The sheet centering device of claim 1 wherein said drive assembly includes a rotatable cam contacting said second sheet guide for moving said guide between said first and second positions.
5. The sheet centering device of claim 4 wherein said drive assembly includes a lift spring engaging said second sheet guide for biasing said guide against said cam.
6. The sheet centering device of claim 1 including imaging nip rollers mounted on said base plate and a skew roller drive for rotating said skew roller so as to move a sheet into contact with on of said guides and along said sheet transport path to said imaging nip rollers.
7. The sheet centering device of claim 1 including means for mounting said skew roller for rotation about an axis perpendicular to said sheet transport path so as to vary the drive angle of said roller in relation to different sized sheets transported along said path.
Type: Application
Filed: Sep 17, 2003
Publication Date: Mar 17, 2005
Inventor: Scott Milton (Maplewood, MN)
Application Number: 10/664,559