Optical chassis

Abstract: A chassis for mounting components in a photographic film scanning apparatus cabinet includes a planar base member, and bearing mounts integral with the base member. The mounts sized and configured to hold bearings against which an arcuate wear plate of a gate of the scanning apparatus registers. The gate is configured to move in a pendulum-like manner across the bearings, with an aperture in the planar member for rotatably accommodating a shaft of a drive system for moving the gate in the pendulum-like manner. Mounts integral with the planar base member are provided for holding an optical system of the scanning apparatus. A continuous integral rib is arranged on the rear surface of the planar member is tuned to a higher natural frequency than that of the scanning frequency for vibrationally isolating the planar base member from other components in the cabinet.

Description: FIELD OF THE INVENTION The present invention relates to a chassis for a photographic film scanning apparatus and, more particularly, to an optical chassis used in a photographic film scanning apparatus of the type which digitizes images on photographic negative film in a film processing laboratory for storage in a CD format, in which the chassis provides a unitary frame for mounting numerous components so as to combine them into a modular interchangeable unit that vibrationally isolates the chassis from the cabinet of the scanning apparatus, and allows prealignment of the scanning apparatus optics prior to the insertion into the cabinet and maintains such prealignment during virtually the entire operation of the scanning apparatus. BACKGROUND ART In conventional scanning apparatus, one approach has been to bolt various mountings for components onto the surface of an optical chassis. More importantly, we have recognized that the chassis used in the known scanning apparatus do not vibrationally and thermally isolate the chassis and its components from the remaining components in the housing, while at the same time, providing for prealignment of the optics so that the optical chassis with all the scanning apparatus (namely the gate, clamp, the gate drive system, the integrating cavity and the lens) can be preadjusted and interchanged with an existing optical chassis in a scanning apparatus. Further, attention is drawn to WO-A-92/03014 ('014) which shows a film scanner comprising a dynamic film gate, said film gate including a pair of capstans for supporting the film at an imaging station and a pair of belts which clamp the film against the capstans. The capstans are mounted on a support structure 22 and are driven to advance the film through the imaging station. Attention is also drawn to SU-A-769 509, 7th of October 1980 and the relevant Database WPI, Section EI, Week 8131, Derwent Publications Ltd., London, GB; Class T06, AN 81-H1482D, in which a rigid body oscillation stabilising method is discussed. Said method is intended for use in stabilising the phase and near-resonant amplitude of forced oscillations of structural elements and machine components featuring viscoelastic links, and it comprises the reduction of the natural frequency to below a harmonic disturbance frequency by thermal and mechanical action on viscoelastic structual links. DISCLOSURE OF THE INVENTION An object of the present invention is to provide an optical chassis which overcomes the problems and disadvantages encountered with prior art chassis. Another object of the present invention is to provide an optical chassis which both vibrationally and thermally isolates the scanning apparatus from the cabinet and provides for prealignment of optics in advance of insertion into the cabinet. A still further object of the present invention is to provide a less massive chassis which serves as a bearing for a scanning gate and reaches thermal equilibrium more quickly so that scanning can take place in steady state over substantially the entire operation of the apparatus such that the desired focus is maintained. Yet another object of the present invention is to provide a less massive optical chassis while enhancing precise alignment between a gate shaft and the image on the film. These objects have been achieved in accordance with the present invention by the provision of a chassis as set forth in claim 1. Said chassis may be cast or machined in one part with all the mounting surfaces for the scanning apparatus components thereon and with ribs that are tuned to a higher natural frequency so as to isolate the chassis and its components from the cabinet and the remaining apparatus components. Preferred embodiments of the invention are claimed in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of a presently preferred embodiment of the optical chassis in accordance with the present invention when taken in conjunction with the accompanying drawings wherein: Figure 1 is a perspective front view of the optical chassis and its scanning components mounted on a frame of the cabinet along with other components such as the reel transport units; Figure 2 is a front elevational view of the system shown in Fig. 1; Figure 3 is a rear perspective view of the system shown in Fig. 1; Figure 4 is a rear elevational view of the system shown in Fig. 3; Figure 5 is an isolated view of the optical chassis in accordance with the present invention with certain of the scanning components removed therefrom; Figure 6 is a rear perspective view of the optical chassis shown in Fig. 5 illustrating the tuning rib for vibration isolation; Figure 7 is a perspective view similar to Fig. 5 but showing only a portion of the optical chassis with the eccentric shafts and bearings for the wear plate of the gate shown in relation to the bearing shaft mounts which are an integral part of the optical chassis; Figure 8 is a rear perspective view of the optical chassis with the various scanning apparatus components mounted thereon; Figure 9 is a front perspective view of the optical chassis showing the gate drive system and the bearings for the gate wear shaft mounted thereon as well as the gate sensors; and Figure 10 is a view similar to Fig. 9 but with the gate, integrating cavity and imaging lens unit mounted thereon. MODE FOR CARRYING OUT THE INVENTION Referring now to the drawings and, in particular, to Figs. 1 and 2, a photographic negative film scanning apparatus for scanning and digitizing images on frames of the film is designated generally by the numeral 10. The apparatus 10 includes a board 11 on which are mounted conventional film transport reels 12, 13, a capstan drive 14, an integrating cavity 15, a conventional imager with imaging board designated generally by the numeral 16, a DX bar code reader 17 for determining the type of film being scanned, a film cleaning apparatus 18, a bar code reader 24 for reading order processing data, and spring-biased tension rollers 19, 20 to maintain the film at a substantially constant tension during the high resolution scanning pass. In addition, other idler rollers 21, 22, 23 and 25 are mounted on the board 11 to maintain a smooth but tight path for the film F shown in long and short dash lines. A gate 100 mounted on an optical chassis 400 and seen in more detail in Fig. 3-9, is rotated, during the high resolution scanning pass in an arc of about 6½° on both sides of a vertical axis constituting an initializing position in which the gate assumes during the low resolution operation. The film F which is supplied from reel 12 shown in Figs. 1 and 2 is advanced by the capstan mechanism 14 by pulling the film F from the supply reel 12 over the gate 100 and onto the take-up reel 13. It will be understood, of course, that the capstan mechanism 14 can be disposed on the right-hand side of the scanning apparatus to push the film F over the gate 100 without departing from the scope of the present invention. A lens protector device 200 is provided in close proximity to the LCM optical scanning mechanism to protect its lens from dust and the like as more fully described in EP-A-0 588 294 entitled LENS PROTECTOR DEVICE, filed in the names of Tomi Lahcanski, et al. on September 14, 1993. Referring now to Fig. 5, the optical chassis 400 can be in the form of, for example, cast aluminum part in which the mounting for the integrating cavity 15, the mountings 402, 403 for the gate sensors, and the mountings 408, 409 for the bearings 404, 405, respectively for registration with a wear plate on the gate 100 are formed integrally with the vertical base 411 of the optical chassis 400. Thus, the reinforced optical chassis serves as a precision bearing mounting surface to maintain the most precise alignment of the gate with the imaging unit 16 possible. On the rear portion of the optical chassis base 411 as shown in Fig. 6, a mounting 414 for the gate drive system can also be integrally cast into the base as well as a continuous rib 413 whose purpose is to isolate the scanning apparatus 10 attached to the chassis 400 from the remaining components of the cabinet by being tuned to a higher natural frequency than the scanning frequency. Moreover, any cabinet vibration caused by non-scanning apparatus will not be transmitted to the scanning apparatus to distort the image being scanned and digitized. One of ordinary skill will know the techniques used to configure and construct the rib which in this embodiment is a continuous rib in a roughly A-shape. It will be appreciated, of course, that depending upon the exact design of the optical chassis 400, the materials used in the scanning apparatus 10 and other variables that the shape and size of the rib 413 may change to achieve the higher natural frequency for achieving vibration isolation. The essential criteria are that the rib provide the tuning to the higher natural frequency while giving reinforcement to the chassis to permit the latter to be made less massive. The less massive chassis, in turn, reaches an equilibrium thermal state much more quickly after start-up and thus allows a steady state operation of the scanning apparatus during virtually its entire operation. It will be further understood that the rib 413, as with the previously mentioned mounting components, is integrally cast into the vertical base 411 of the optical chassis. For ease of illustration, only certain of the components have been shown as being filleted to designate integral casting with the understanding, however, that all the parts shown on the optical chassis of Figs. 5 and 6 are integrally cast. The overall integral chassis unit thus achieves a stiffness which maintains the focus necessary for high resolution while the less massive chassis allows this focus to be maintained over the span of operations of the scanning apparatus which can be for several hours at a time. Fig. 7 shows in somewhat more detail how gate wear plate bearings 404, 405 and respective eccentric shafts 406, 407 are mounted on the optical chassis 400 with retaining plates 412 being screwed or bolted into the mounting surface. Fig. 8 shows how the gate drive system 500, the details of operation of which are not here relevant, is mounted compactly on the optical chassis 400 on the rear surface at the mounting portion 414. An aperture 415 in the vertical base of the optical chassis 400 is provided to accommodate the solenoid and solenoid mounting plate for the clamp mechanism 300 mounted on the gate 100 for clamping the film to the gate 100 for transportation with the gate. Details of the gate 100 are disclosed in EP-A-0 588 293 entitled ARC-SEGMENT-SHAPED GATE FOR PHOTOGRAPHIC FILM SCANNING APPARATUS filed in the names of Eric P. Hochreiter, et al. on September 14, 1993. Likewise, details of the operation of the clamp are described in EP-A-0 588 308 entitled CLAMPING ARRANGEMENT FOR FILM SCANNING APPARATUS filed in the names of Tomi Lahcanski, et al. on September 14, 1993. The details of the gate drive system are further described in EP-A-0 588 309 entitled SCANNING APPARATUS GATE DRIVE SYSTEM filed in the names of Eric P. Hochreiter, et al. on September 14, 1993 although not necessary for a full understanding of the optical chassis 400 itself. Fig. 9 shows the eccentric shafts 406, 407 and their bearings 404, 405 fully mounted on the optical chassis 400, as well as the gate 100 sensors which detect the end of movement of the gate in a pendulum-like manner during normal scanning operations. Furthermore, the shaft 502 upon which the spherical bearing 104 of the gate 100 is mounted also extends through the front portion of the optical chassis and is part of the gate drive system 500. Finally, Fig. 10 shows the optical chassis 400 with the gate (except for idler rollers 107, 109), integrating cavity 15 which contains a heat generating lamp, imager 16 and imaging board 16' mounted thereon. Thermal isolation of the lamp of the integrating cavity 15 from the chassis 400 is achieved with a phenolic block 416 mounted to the chassis. It will be apparent from this view that the optical chassis 400, in addition to providing superior reinforcement for the scanning apparatus cabinet, provides an integral module which permits prealignment of the scanning apparatus optics prior to insertion of the chassis into the scanning cabinet and also provides interchangeability of the entire scanning apparatus for easier servicing and repair. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example, and is not to be taken by way of limitation.

Claims: A chassis (400) for mounting components in a photographic film scanning apparatus cabinet, said chassis comprising a planar base member (411), a phenolic block (416) mounted on said planar base member (411) for accommodating a lamp of the scanning apparatus, bearing mounts (408, 409) integral with the base member (411), and sized and configured to hold bearings (404, 405) against which an arcuate wear plate of a gate (100) of the scanning apparatus (10) registers, the gate (100) being configured to receive light from the lamp and to move in a pendulum-like manner across the bearings (404, 405) to allow film scanning by an optical system of the scanning apparatus, an aperture (401) in the planar base member (411) for rotatably accommodating a shaft (502) of a drive system (500) for moving the gate (100) in the pendulum-like manner, mounts integral with the planar base member (411) for holding the optical system of the scanning apparatus (10), mounts (402, 403) for gate positioning sensors integrally provided on the planar base member (411) in proximity to the bearing mounts (408, 409), and vibration isolating means (413) on the planar base member (411) for vibrationally isolating the planar base member (411) from other components in the cabinet, wherein the vibration isolating means comprises a continuous rib (413) designed and manufactured so as to have a natural frequency higher than the scanning frequency of the gate. The chassis (400) according to Claim 1, wherein a mount (414) integral with a rear face of the planar member (411) has the drive system (500) connected therewith. The chassis (400) according to Claim 1, wherein the chassis (400) constitutes a rigid bearing support to assure precise positioning of the gate (100) relative to the optical system.

Inventors: EHRNE FRANKLIN D, FISHER SR TERRENCE L, HOCHREITER ERIC, EHRNE, FRANKLIN D., FISHER, SR. TERRENCE L, HOCHREITER, ERIC, Ehrne, Franklin D., c/o Eastman Kodak Comp., Fisher, Sr. Terrence L. c/oEastman Kodak Comp., Hochreiter, Eric P., c/o Eastman Kodak Comp.
Applicants: EASTMAN KODAK CO, EASTMAN KODAK COMPANY
Application year: 1993
Main classification: H04N1
IPC codes: G03B27, H05K7, H04N1, G03B1