CA1125355A

CA1125355A - Imaging apparatus

Info

Publication number: CA1125355A
Application number: CA339,498A
Authority: CA
Inventors: Mark H. Mccormick-Goodhart
Original assignee: Energy Conversion Devices Inc
Current assignee: Energy Conversion Devices Inc
Priority date: 1978-11-17
Filing date: 1979-11-08
Publication date: 1982-06-08
Also published as: FR2441869A1; IT7927372A0; JPS55108650A; GB2036991A; IT1125819B; BE880077A; FR2441869B1; GB2036991B

Abstract

IMAGING APPARATUS

Abstract of the Disclosure Dry-process imaging apparatus for flash format imaging an imaging film having a layer of an energy dispersible image forming material on a surface thereof. The apparatus comprises a source of electromagnetic or radiant energy, radiant energy collecting and guiding means, and support means including masking means for the imaging film. The apparatus is especially suitable for flash format imaging microfiche cards, and enables an imaging energy source such as, for example, a Xenon flash tube, to be operated at lower energy levels for shorter time periods while achieving uniformity of energy distribution over a comparatively large area at the film plane.

Description

~ ~2~35~i The presen-t invention relates to apparatus for ¦I dry~process, flash format imagi}lg an .imacJillg film having a layer ~ ~;
¦l of an energy dispersible image forming material on a surface thereof.

Il I
¦~ Apparatus for dry-process, flash imaglng an imaging film having a layer of an energy dispersible image forming material on a surface thereof is disclosed in U.S. Paten-t No.
3,966,317. The apparatus shown in the patent in~ludes an image transferring station where a single frame on a microform , fil~ is interposed over a microimacJed frame in a mask .Film strip positioned above a glass windo~. A short pulse o' energy, above ,: . , ;3S~;

i a threshold value, emitted by a Xenon flash tube is passed through the glass window ancl the microimaged frame of the mask Eilm strip onto the frame of the microform film which, preferably,l is in the form of a microfiche or microform carcl. The energy pulse emit-ted by the Xenon flash tube is absorbed and sca-t-tered by the opaque areas of the microimaged frame o the mask film strip so as not to effectively reach the corresponding areas of energy dispersible material oE the overlying frame of the micro-form film. However, the short energy pulse readily passes through the substantially transparent areas of the microimaged frame of the mask film strip to the corresponding overlying areas of energy dispersi.ble material of the microform film where the energy pulse is abSOrbed. The absorption of the energy pulse by these areas heats the energy dispersible materi.al to at least a softened or molten condition, whereupon the continuous layer of energy dispersible material at those areas is broken up and dispersed into small and.widely spaced globules to make Ithose areas substantially transparent. The dispersion of -the energy dispersion material at the heated areas is occasioned, in the main, by the surface tensi.on of -the heated matcrial which causes the heated material to form such small and widely spaced globules. After the globules are so formed by the shor-t pulse of energy emitted by -the Xenon flash tube, they quickly cool and I
remain in that globular condition to provide subs-tantially transparent areas in the frame of the microform film.

Since the apparatus of Patent No. 3,966,317 is concerned ~/ith microi.maging only a comparatively small area, namely, a single frame of a microfiche or microform card, the greater proportion of the energy emitted by the Xenon flash tube is dissipated, resulting in inefficient use of the energy emitting capabili-ties of the flash tube and, concomitantly, a shortened useful life for the flash tube.
~ n accordance with the present invention, a dry-process imaging apparatus is provided which not only enables more efficient collection of the energy emitted by an energy source such as an Xenon flash tube thereby permitting the energy source to be energized at a lower potential for a shorter time, and, concomitantly, prolonging the useful life of the flash tube, but, also, enables the energy emitted by the energy source to be guided along a predetermined path whereby optimum uniformity of distribution of the emitted energy at the film plane is achieved. ~s a result, larger areas of imaging film can be uniformly imaged with the apparatus enabling an entire microfiche card to be imaged with a single, short pulse of energy. The apparatus of this invention can be employed as a separate, self-contained unit for the production of non-image bearing microfiche

2~ cards having add-on capabilities, or for transferring micro-images on conventional microfiche cards, such as diazo microfiche cards which have no add-on capabilities, to cards having an energy dispersible imaging material layer -thereon which imparts both add-on and annotative capabilities to the cards, and which, furthermore, having superior archival properties.
Generally, the presen-t invention provides an apparatus for flash format imaging an imaging film having a layer of an energy dispersible image forming material thereon.
The apparatus includes an energy source capable of emitting electromagnetic energy of an in-tensity sufficient -to cause dispersion of the energy dispersible image forming material on ,~, Ws/?~

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~ne imaging film. Imaging film support means is positioned in spaced relation to the energy source for enabling electromagnetic energy from the source to be applied to the imaging film in a preselected pattern. ~n electromagnetic energy collecting and channeling means is provided for directing energy from the energy source to the irnaging film at the film support means.
The electromagnetic energy collecting and channeling means includes an electromagnetic energy passageway and guideway for intercepting and entrapping a maximum amount of the electro-magnetic energy from the energy source and direc-ting it to the imaging film whereby substantially the full intensity of the electromagnetic energy is applied to the imaging film thereby enabling rapid and substan-tially uniform dispersion of the energy dispersible image forming material on the film, in a preselected pattern, to be achieved.
The foregoing, and other features and advantages ws/ ~/~

~2S35~

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of the imaginy apparatus of this invention will become apparent to -those skilled in the ar-t upon reference to -the accompanying specifica-tion, claims and drawinys in which:

FicJ. 1 is a view in perspective, partly in section and partly exploded, of an embodiment of the imaying apparatus;

~' Fig. 2 is a sectional view -taken substantially Il along line 2-2 of Fig. l;
i, 1 Fig. 3 is a sectional view taken at a 90~ angle to the view of Fi~. 2;

Fig. 4 is a fragmentary sectional view taken substantially along line 4-4 of Fig A 1;

Fig. 5 is a fragmentary sectional view taken substantially along line 5-5 of Fig. 2; and ¦ Fig. 6 is a fragmentary sectional view taken subs-tantially along line 6-6 of Fig 5.

Referring, now, in greatex detail to the drawings, as best shown in Fig. 1, the embodiment of the imaging apparatus jl illustrated, and designated generally by reference numeral 10, comprises an outer frame 12 in which is suppor-ted an inner frame 14. The ou-ter ~rame 12 is formed by Eour vertical, an~led corner members 16 joined at their top and bot-tom margins to ~, anglecl connectors or cross-pieces 18. The members 16 and 18 ;i desirably are formed of metal, but can be made of a rigid plastics material, or the lil-e. The outer rame 12 is nrovidec' ~ith a bottom wall 22, a rear or back wall 2~ and a to~> wall 26.

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, ; The hottom wall 22 and the rear wall 24 aclvantageously are formed of an insulating material such as plastic, composition board, a compressecl mineral aycJreyate, or the lilce. The top wall 26 of the Erame 12 desirabl~ is formed of metal, and has a centrally loca-ted, generally rectangular opening 26a provided therein, -the purpose of which will become clear as the description proceeds.
~he sides and ends of the outer frame 12 may be enclosed with panels 20-20 to give the apparatus a finished appearance and t~
preven-t unauthorized tampering with the interior of the apparatus~

The inner frame 14 of the imaging apparatus 10 comprises side walls 14a and end walls 14b which are secured along their upper margins to -the top wall 26 of the outer frame 12 at the opening 26a therein.

li il The inner frame 14 of the appar.~tus serves as a support for a hollow, open-ended, electromagnetic or radian-t energy intercepting and guiding element 30. In the embodiment j of the invention illustrated, the radian-t energy intercepting and guiding element 30 comprises two pairs of mirrors 32-32 and 34-34 positioned with their reflective surfaces in opposed ; relation to one another and arranged to form a hollow, elongated, open-ended, rectangular passayeway As best shown in Fig. 4, the end mirrors 32-32 are slightly narrower in width than the side mirrors 34~34, and are joined at their margins along the margins of the side mirroxs 34-34. To this end, a suitable adhesive such as an epoxy resin may be used to secure the mirrors in position. The backs of the mirrors, in turn, are secured to the walls 14a and 14b of the inner frame 14. While ~25 I' the mirrors 32-32 and 34-34 may be of various types, they preferably are front surace al~inum coated type mirrors.

Positioned belo~ -the inner Erame 14 and i-ts " associated radian-t energy intercepting and guiding element 30 is ~¦ a radiant energy source which, in the embodiment of the invention shown, comprises a Xenon linear flash tube 40. The ends of the tube 40 are supported in insulator blocks 42-42 which are attac:hed to angled crosspieces 44-44 secured on ver-tical members 16 of ~he outer frame 12. The terminals of the tube 40 are connec-ted to an energi2iny source (not shown) through leacls 46-~6. The tube j 40 may be oE any desired size but preferably is a broad band type having a range from UV to inErared with wavelengths of about 2000A to lOOOOA, and an arc length oE 8 inches. Exernplary of such a tube is Model No. FX-77C-8 of EG & G Company.

¦l Arranged below the tube 40 is a vertically adjustable electromagnetic or radiant energy reflecting element 50. The elemen-t 50 advantageously comprises a pair of elongated ~I mirrors 52-52. The mirrors 52-52, like the mirrors 32 and 34 ¦l desirably are front surface aluminum coated. ~s shown, the mirrors 5~2-52 are ]oined to one another along their inner longitudinal margin 52a and form an approximate right angle along.their line of juncture~ The ends of the mirrors 52-52 'I - ;
are supported in openings or slots formed in ver-tically adjus-table panels 54-5~ secured to the end walls 14b of the inner frame 14 by knurl headed bolts 56 engaged in tapped bores in the end walls 14b throuc;h elonga-ted vertical slo-ts 58 formed in the panels 54-54. The panels 54-54 desirably are fabrica-tecl of a plasti~s '~ " ' ' ' ' ' material SUCII as Plexiglas, or o~ a ligllt weight metal such as aluminum. ~djustment oE the element 50 to~ard or a~ay ~rom the tube 40 enables greater uniformity o radiant energy dlstribution to be achieved at the ~ilm plane.

Imaging fi]m -to be flash formatt:ed with the apparatus of the present invention is supported on a film receiviny member 60. In the preferred en~odiment of the apparatus, the member 60 comprises a quartz plate which is supported on the upper margins of the inner frame 14 at the upper open end of the radiant eneryy intercepting and yuiding element 30. The quart~ plate advantageously is formed o~ a high grade quartz available conunercially under the designation Arnersil*, Supersi~, !
Grade T, or T2. Th~ quartz plate can vary in thickness,but desirably has a thickness of the order o about 60 mils to about 1/2 inch. As best seen in Fig. S, the upper surface of the t men~er 60 has an image or pattern 60a formed on it. The image or pattern 60a is reerred to as a mask, and is formed on the surface of the member 60 by applying a thin layer of a metal such as chromium, for example, on the upper surface of the member 60, and then coating the metal layer with a photoresist.
An image is ormed in the photoresist layer by exposing it to elect~omagnetic radiation through a master having an imaye or pattern corresponding to the image or pattern desired to be ~ormed on the sur~ace-oE the member 60. Utilizing conventional etchiny techniques, the desired imaqe or pattern is then etched in the metal layer.

The member 60 is maintained in position on the * - Trade Mark .. ... . . _ . . . . ... .. _ _ _ . .
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inner frame 14 by a retaining p:late 62 provided ~ith a centrally . located rectangular opening 62a. The plate 62 has a recess 62b . formed in one side thereof to facilitate remova]. of a pressure "
plate 64 and a re~istration plate 66, each of which is posi-tioned .

I in superimposed rela-tion to .film supported on the member 60 during ;1 imaging. Projections or pins 68-68 are provided on the retaining plate 62, and are adapted to be received in openings 66a-66a in Il the registration plate 66.

:i The imaging film employed with the apparatus of ,. :
, this invention.preferably is in the form of a microfiche or l! . !
, microform card. A preferred form of the microfiche or microform ¦ card is disclosed in U.S. Patent No. 3,966,317. As shown in that patent, the card comprises a flexible and substantially trans-parent synthetic plastic substrate such as Mylar (polyethylene I -glycol terephthalate)l for example, having a thickness in the , range of from about 7 to about 15 mils. Coated 031 the substrate,l : ¦
preferably by vacuum deposition, is a thin, continuous solid layer of an energy dispersible image forming material such as bismu,h, or a bismuth alloy, having a thickness of from about ,l 1000 to about 2000A. The layer of energy dispersible image i! formlng material is heat absorbing, and, in the case of bismuth, !I has a melting point of about 271C. A protective overlayer ' advantageously is applied on the energy dispersible layer. The ~, protective overlayer desirably comprises a substantially trans-parent synthetic plastic film of Saran, polyurethane, or the like, and has a thickness of about 1 micron. The card measures approximately 4 x 6 inches.

In utilizing the imaging apparatus to form an _ 9 _ L12~
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1 ~ -10 I image on a microfiche or microform card correspondiny to the imaye or pattcrn of the quartz mask as represented by the pattern 60a on the member 60, a card having the struc-ture described above is placed on the member 60 wl-th the protective overlayer in contact with ~he quartz plate. The pressure plate 64 is then placed on the card and the registration plate 66 is -positioned in engagement with the studs 68-68 on the retai~ing--plate 62. The Xenon flash tube 40 is energized to provicle a lshort pulse of elec-tromagnetic or radiant energy. The short pulse of energy produced by the tube 40 is within the range of about 1 millisecond to about 40 microseconds, preferably about ¦100 microseconds. Due to the combined high energy collection efficiency of the element 30 and the element 50, the flash pulse is approximately 40~ to 50~ shorter than would be otherwise ¦Ipossible. Concomitantly, the energization of the tube 40 can lltake place at a lower operating potentialO These factors combine ¦¦ to appreciably extend the useful life of the tube 40, enabling ~ up to 100,000, or more, flashes to be obtained from a single ¦! Xenon tube of the size described above.
i ' ' :
The short pulse of energy emltted by the tube 40 readily passes through the transparent areas of the mask 60a ~ formed on the member 60, and the protective overlayer on the energy dispersible material layer comprising the microfiche card, to the layer of energy dispersible material where the jl ¦ energy is absorbed. This absorption oE the energy heat by the energy disp~rsible material at these areas causes the energy cdispersible material to become soft or mol-ten, whereupon the continuous solid layer of energy clispersible material at the il :
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areas where the energy is absorbed is broken up and dispersed into small and w.idely spaced glohules -to make these areas sub-stantially transparent. The dispersion of the enerc~y dispersible material at the energy heated areas is occasioned in the main by the surface tension of the heated material -to form such small ~.
and widely spaced globules. Again, due to the combined highly efficient energy collec-ting capabilities of -the elements 30 and 50 of the apparatus, and their ability to collima-te and direct the energy toward the plane of the microfiche card, dispersion of the energy dispersible material in the areas thereof where eneryy absorption occurs, takes place subs-tan-tially uniformly over the entire card. After the glohules are so formed by the short pulse of energy from the tube 40, they almost instantaneously cool and remain in that globular condition to provide a sharp, high resolution pattern or image on the card corresponding to the pattern or image of the mask 60a on the member 60.

hile the apparatus has been described with relation to the production of a microfiche card on a one by one basis, it should bepointed out tha-t film in rolJ. form, from which i.ndividual cards may be cut after imaging, can be fed automatically into the imaging area of the apparatus, and, after imaging, taken up on a roll for later use~. Also, the size of the I :
imaging.area, and the pattern on the mask, can be varied as desired to produce smaller cards or to image only a limited area of a card. It should be understood, therefore, that these !
changes, as well as other modifications, may be made in the p-referred form of the invention descrihed herein without deviating from the broader aspects of -the inventi.on.

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Claims

What is claimed is:

1. Apparatus for flash format imaging an imaging film having a layer of an energy dispersible image forming material thereon, comprising: an energy source capable of emitting electromagnetic energy of an intensity sufficient to cause dispersion of the energy dispersible image forming material on the imaging film, imaging film support means positioned in spaced relation to said energy source for enabling electromagnetic energy from said source to be applied to the imaging film in a preselected pattern, and electromagnetic energy collecting and channeling means for directing energy from the energy source to the imaging film at the film support means, said electromagnetic energy col-lecting and channeling means including an electromagnetic energy passageway and guideway for intercepting and entrapping a maximum amount of the electromagnetic energy from the energy source and directing it to the imaging film whereby substantially the full intensity of the electromagnetic energy is applied to the imaging film thereby enabling rapid and substantially uniform dispersion of the energy dispersible image forming material on the film, in a preselected pattern, to be achieved.

2. Apparatus according to claim 1 wherein the imaging film support means includes masking means bearing an image of at least one area which has a high transmissiveness for the electromagnetic energy from the energy source and at least one other area which has lesser transmissiveness for said energy.

3. Apparatus according to claim 1 wherein the electromagnetic energy collecting and channeling means includes a hollow, open-ended element having an electromagnetic energy reflective surface.

4. Apparatus according to claim 3 wherein the hollow, open-ended element comprises a plurality of mirrors in contact with one another along their respective adjacent margins and having their reflective surfaces positioned in substantially opposed relation to one another.

5. Apparatus according to claim 3 wherein one end of the hollow, open-ended element is positioned adjacent to an electromagnetic energy source, and the other end thereof opens at the imaging film support means.

6. Apparatus according to claim 1 wherein electromagnetic energy collecting and reflecting means is positioned adjacent to the electromagnetic energy source in opposed relation to the electromagnetic energy collecting and channeling means, said energy collecting and reflecting means acting to intercept energy from said source and reflect it toward the energy collecting and channeling means.

7. Apparatus according to claim 2 wherein the imaging film support means includes an electromagnetic energy transmissive plate member adapted to support an imaging film on a surface thereof, said plate member having an imaging mask formed on the imaging film supporting surface thereof.

8. Apparatus according to claim 1 wherein the electromagnetic energy source is a linear Xenon flash tube.

9. Apparatus according to claim 7 wherein the energy transmissive plate member is formed of quartz, the upper surface of which carries a metallic mask comprising a pattern for imaging film supported thereon.

10. Apparatus according to claim 6 wherein the energy collecting and reflecting means comprises mirrors, the reflective surfaces of which are arranged at an angle with respect to one another and face in the direction of the energy source.