Apparatus for media guidance in an imaging device

Abstract: A media guide (10) for assisting in threading the head end of a rolled, radiation sensitive media through an imaging station (18) in an imaging device. The media guide has a longitudinally extending arcuate input media guide and (20) and a parallel longitudinally extending arcuate output media guide (22) with the open arcuate surfaces thereof facing in the same direction. A longitudinally extending imaging aperture slot (24) is positioned between and parallel to the arcuate input (20) and output (22) media guides. The input side of the imaging aperture slot (24) is located above the output side of the aperture to prevent the media from catching in the aperture slot.

Description: The present invention relates to imaging devices in general and, more particularly, to a media guide for assisting in the threading of rolled media through the imaging station of the imaging device according to the preamble of claim 1. An imaging device of that kind is known from US-A-3 975 749. Imaging devices utilizing a film supply cassette and a take up cassette are well known in the art. Such devices typically employ drive rolls to pull the media out from the supply cassette and through an imaging station at which the film is imaged and then to the take up cassette. Initially, the film must be pulled from the supply cassette and through the imaging station until the film can be engaged by the drive rolls. The threading procedure can be awkward and difficult. It is, accordingly, a general object of the invention to provide a media guide to assist in threading rolled media through the imaging station of an imaging device in a manner which keeps clear the optical way. It is a further feature of the invention to provide a media guide having an imaging aperture slot. It is also a feature of the media guide that debris from the media is effectively sealed from the optical portion of the imaging device. According to another feature of the invention the configuration of the guide prevents the media from entering the imaging aperture slot during the media threading operation. These tasks are accomplished by the features of present claim 1. More particulars, features and advantages of the invention can be taken from the following detailed description of a preferred embodiment selected for purposes of illustration and shown in the accompanying drawings, in which: Figure 1 is a diagrammatic view in perspective of an imaging device incorporating the media guide of the present invention; Figures 2 through 5 are views in side elevation and partial section illustrating sequentially the media threading operation through the media guide; and, Figure 6 is an enlarged view in side elevation and partial section showing the media in the imaging position. Turning now to Figure 1 thereof, there is shown in diagrammatic form and perspective an imaging device indicated generally by the reference numeral 10. The imaging device 10 contains a media supply cassette 12 having a cassette feed aperture 14 through which exits radiation sensitive media e.g., film (not shown). The film passes over an input tension roll 16 and through a media guide 18 having a longitudinally extending, arcuate input media guide 20, a parallel longitudinally extending arcuate output media guide 22 and a longitudinally extending imaging aperture slot 24 that is parallel to the longitudinal axes of the input and output media guides, 20 and 22, respectively. In the operative position during imaging by a scanning beam 26, the film is in contact with capstan 28 (as shown in Figure 6). Upon exiting from the capstan 28, the film passes over an output tensioning roll 30 and through drive rolls 32 and 34 to a cutter block 36 and then into the take up cassette 38. Referring now to the sequential illustrations of Figures 2 through 5, there is shown in side elevation and partial section the threading operation of a film 40. As shown in Figure 2, the film 40 is pushed into the input media guide 20 and then pushed downwardly into the arc of the input guide 20 and over the imaging aperture slot 24 as depicted in Figure 3. It can be seen from Figure 3 that the film is ramped upwardly, as viewed in Figure 3, by a ramp portion 42. The imaging aperture slot 24 has an input side 24a and an output side 24b with the output side located below the input side 24a. This arrangement prevents the film 40 from catching in the imaging aperture slot 24 as the film is pushed from left to right as viewed in Figures 3 and 4. Continuing in sequence, the film is then pushed to the right as viewed in Figure 4 and encounters the arc of the output guide 22. Once the film has encountered the arcuate surface of the output guide 22 further pushing in the direction from left to right as viewed in Figure 5, causes the film to buckle upwardly where it can be caught by a finger and pulled through and out of the media guide 18. Alternatively, the film can be pushed downwardly as viewed in Figure 5 and then further pushing will cause the film to move upwardly beyond the upper surface of the output media guide as viewed in Figure 5. Referring now to Figure 6, the structural components of the media guide 18 are shown in enlarged detail with the film 40 wrapped around capstan 28. The scanning beam 26 forms an image on film 40 at image station 44. It will be appreciated from an inspection of Figure 6 that debris from media 40 will fall into the troughs formed by the arcuate input media guide 20 and the arcuate output media guide 24 rather than into the optical system of the imaging device. For this purpose an input side 46 of a wall portion 42 of the imaging aperture slot 24 is located above an output side 48, which is straight extended to the curvature 22. The length of a radius r 20 of the input media guide 20 is greater than the length of a radius r 22 of the output media guide 22. The center M 22 of curvature of the output media guide 22 is lower located (1) than the center M 20 of curvature of the input media guide 20. Moreover, the horizontal distance a of the center M 20 of curvature of the input media guide 20 is smaller than the horizontal distance b of the center M 22 of curvature of the output media guide 22 to the in Fig. 6 vertical directed scanning beam 26. Having described in detail a preferred embodiment of my invention, it will now be apparent to those with skill in the art that numerous modifications can be made therein without departing from the scope of the invention as defined in the following claims.

Claims: A media guiding apparatus (10) for use in an imaging device employing radiation sensitive media (40) in roll form, said media guiding apparatus (10) comprising: (a) a longitudinally extending input media guide means (20) for guiding the radiation sensitive media (40) through an input arcuate path with the longitudinal axis of the input media guide means being normal to the direction of movement of the radiation sensitive media (40) through said input arcuate path; (b) a longitudinally extending output media guide means (22) for guiding the radiation sensitive media (40) through an output arcuate path with the longitudinal axis of said output media guide means being normal to the direction of movement of the radiation sensitive media through said output arcuate path and parallel to the longitudinal axis of said input media guide means; and (c) a longitudinally extending imaging aperture slot means (24) positioned between said input (20) and output (22) media guide means with the longitudinal axis of the imaging aperture slot means (24) being parallel to the longitudinal axes of said input and output media guide means, characterized in that said input media guide means (20) and said output media guide means (22) are of concave shape. The media guiding apparatus (10) of claim 1 wherein said input media guide means (20) and said output media guide means (22) are static, fixed guide members. The media guiding apparatus of claim 1 or 2 wherein the input and output media guide means have different length radii (r 20 , r 22 ). The media guiding apparatus of claim 3 wherein the length of the radius (r 20 ) of the input media guide means (20) is greater than the length of the radius (r 22 ) of the output media guide means (22). The media guiding apparatus of claim 1 or 2 wherein the center (M 22 ) of curvature of the output media guide means (22) is lower (1) than the center (M 20 ) of curvature of the input media guide means (20) with respect to the gravity field vector during use of the imaging device. The media guiding apparatus of claim 1 or 2 wherein said input media guide means (20) includes means defining a longitudinally extending ramp means (42) for the media (40), said ramp means (42) terminating at said imaging aperture slot means (24). The media guiding apparatus of claim 1 or 2 wherein said imaging aperture slot means (24) includes a first side wall (46) facing the input media guide means (20) and a second side wall (48) facing the output media guide means (22) and wherein said first side wall (46) terminates at a location with respect to the gravity field vector that is higher than the second side wall (48). The media guiding apparatus of claim 5 wherein with respect to the right angular scanning beam (26) the distance (a) of the center (M 20 ) of curvature of the input media guide means (20) is smaller than the distance (b) of the center (M 22 ) of curvature of the output media guide means (22).

Inventors: HEBERT THOMAS K, HEBERT, THOMAS K.
Applicants: BAYER AG, BAYER CORPORATION
Application year: 1993
Main classification: G03B27
IPC codes: G03B27, H04N1