US2743653A - Photographic contact printing apparatus - Google Patents

Description

May 1, 1956 w. D. KENNEDY ETAL 2,743,653

PHQTOGRAPHIC CONTACT PRINTING APPARATUS 5 Sheets-Sheet 1 Filed March 4, 1955 WALTER DAVID Kenn EDY S DNEY JOSEPH FENTON BJ/VMMWM May 1, 1956 w. D. KENNEDY E AL 2,743,653

PHOTOGRAPHIC CONTACT PRINTING APPARATUS 3 Sheets-Sheet 2 Filed March 4, 1953 l1 k L) n 3 u n v F 3 u mw x A "Rh :5 I i A w mwun plfiwwnn lhwmWWMMMWMMHUM kw. Q n 5 x i n a i I 7 {mi LLMMWT: |l||!l|Il||||| .r llllllll I! m. i; x I a M E-whfihir lfl'l I 1 I HHHHHHE IH LH I u wfxw ww a ran. Q .l||T||||||||| A2 WALTER DAVID KENNEDY SIDNEY JOSEPH FENTON May 1, 1956 w. D. KENNEDY ETAL 2,743,653

PHOTOGRAPHIC CONTACT PRINTING APPARATUS Filed March 4, 1955 Sheets-Sheet 3 WALTER DAvm KENNEDY SHDNEY JOSEPH F'ENTON United States Patent PHOTOGRAPHIC CONTACT PlilN TIN G APPARATUS Walter David Kennedy and Sidney Alfred Joseph Benton, London, England, assignors, by mesne assignments, to Chemische Fabriek L. van der Grinten, N. V., Venlo, Netherlands, a corporation of the l letherlands Application March 4, N53, Serial No. 346,244 Claims priority, application Great Britain March 7, 1952 1 Claim. (Cl. 95-575) The invention relates to photographic contact printing apparatus, comprising a rolling panel of translucent material curved in one direction, provided on its convex side with a flexible applying apron for applying under tension and for pressing the material to be exposed on to the panel, the said applying apron extending tangentially oil the panel in the feeding position of the apparatus and following the surface of the panel in the working position of the apparatus.

The time during which the apparatus, to which the material to be exposed has been fed, has to be in the Working position is determined by the exposure time, which depends on the luminous power of the source of light, on the sensitivity of the light-sensitive material, and on the translucency of the original to be copied. This exposure time varies, and has to be previously ascertained in each case. I

When the exposure time has elapsed, it is desirable for the apparatus to return as quickly as possible to the feeding position, in order to avoid any further, mainly local, over-exposure of the material during this returning movement.

In order to facilitate the operation of the apparatus in this respect, according to this invention, the influence of gravity or of some other force is brought to bear on the panel in such a way that it is always drawn towards the feeding position (i. e. the position of rest), while a locking device is provided, by means of which it can be locked in the working position.

When the locking device in question is unlocked, the panel rolls back to the feeding position, with the applying apron being flattened out again.

By the application of the invention it is made readily possible to interrupt the exposure time automatically. In fact, according to the invention the locking device may be provided with a timing device adapted to unlock the locking device. It is thus sufficient on the one hand, when a copy is to be made, to place the apparatus in the working position and on the other hand to adjust the timing device to the desired exposure time. As soon as this time has elapsed, the apparatus returns automatically to the feeding position, the exposure thus being interrupted.

In the drawings an embodiment of the invention is illustrated.

Fig. 1 is a part-sectional end elevation of the appa ratus.

Fig. 2 is a part-sectional side elevation of the apparatus.

Fig. 3 is a view of the timing unit in the apparatus at rest with parts taken away.

Fig. 4 is a View of the whole timing unit in the working position.

Referring to these drawings, the apparatus comprises essentially a box-like structure or support 11 having a sloping upper surface (rising from 12 to 13) and carrying a rolling unit containing an electric lamp 14 capable of emitting ultra-violet radiation, and wheels 15 on which the unit rolls. Associated with the rolling unit is an apron 16 adapted to wrap around the rolling unit. Stated in greater detail the apparatus is as follows.

A box-like structure 11, conveniently made of sheet metal, is so constructed that when stood on a level surface it has a sloping upper surface, the level rising from 12 (the rear or back of the apparatus) to 13 (the front or working end of the apparatus). Near to this upper surface and on the sides of the structure 11 are channel shaped members 17 and 18 of which the channels open outwards. On one side of the structure 11 is a chamber 19 which is of sufficient width to house a power supply cable 28 for the lamp 14. On the other side of the structure 11 is mounted a timing unit 26 of the character described in this application.

At the rear end of the structure 11 is a compartment 21 housing an electrical transformer 22 and provided with ventilating apertures 60. The transformer 22 is usually necessary because the supply voltages obtainable are insufiicient to power the form of lamp, e. g. a high-pressure mercury vapour lamp, which is most suitable for the apparatus of this invention. Where this situation does not arise, however, the transformer unit may be omitted.

Mounted in the open front of the structure 11 is a bar 23, bent at the ends and pivoted at pivots 24. There passes round this bar 23 and a floating bar 26 a fabric band 50 held under tension by reason of the bar 26 being secured by springs (not shown) to the rear of the structure 11, adjusting knobs 27 being provided to enable its tension to be evenly adjusted across its width. The bar 23 may be moved up and down on the pivots 24, its movement being limited by an upper stop 29 and a lower stop 30. The springs are located so that in this movement the bar passes over the dead-centre position and is thus held by the springs in one or other of the end positions.

The rolling unit referred to above comprises an electric light 14, a part cylinder of glass 31 and a complete cylinder of glass 32, the arrangement being such that when the unit is rolled forward, the wheels 15 running on the tracks formed by the channel sections 17 and 18, the part cylinder 31 wraps around itself the apron 16. The two wheels 15 are held together by tie-rods 33 and support the part cylinder 31 so that its outer surface is at almost the same radius from the centre of rotation as the rims of the wheels 15, the weight of the unit, however, being carried by the wheels 15.

Mounted within the wheels 15 and supported by three ball races 34 in each wheel 15 is a metal cylinder 35. The cylinders 35 make telescopic engagement with a central cylinder 36 the main part of which is cut away to provide an aperture for light from the lamp 14 to emerge through the cylinder 32. The cylinders 35 have rims 37 which engage in the mounts for the ball races 34 and prevent end-wise movement of the cooperating cylinders 35 and 36. The arrangement is therefore such that rotation of the wheels 15 carries the unit along the tracks 17-18 causing simultaneous rotation of the part cylinder 31, which mo es with the wheels, but causing only a translational movement of the axis of the cylinder 32 and lamp 14. The lamp 14 therefore only gets the necessary and also a simple and quiet movement which is of considerable importance for the life of same.

The ends of the lamp 14 are held in clip type contacts 38 mounted on an insulating block 39, one electric contact being at one end of the tubular lamp and the other at the other end of the lamp. The block 39 is held by extensions of the end cylinders 35 and also secured to end plates 40 which are provided with heat-dissipating fins 41. Each end plate 40 is provided with a guide roller 42 housed within the channels 17 and 18 so that on rolling movement of the wheels 15 the end plates 40 are checked against any tendency to rotate with the wheels,

i. e. the end plates 40 and the cylinders 32?, 35 and :36

and the lamp 14 are held against rotation.

S u ed. at o the Wheels. 15 i an ap n .1 wh ch extends along the surface of the structure 11, secured to same at the forward end by turning it over at the Pr edge afthe or ard en of the stru ture and returns within the structure ,to be held under tension by springs, not shown, to the rear wall of the structure 11 .The apron is made up of a plurality of juxtaposed fabric strips. Adjustment screws (not shown) for the tension-:

V tially prevented. The hood 45 carries'a handle 46 by means of which the rolling unit may be drawn forward.

The rearward motion of the rolling unit is checked by wedge-shaped rubber stops 47' located in the channels 17 and 18 and the forward movement is checked by contact between a spring-loaded buffer unit 51 lo cated on the skirt of one of the end plates 40 and a lever 48 forming part of the timing unit 20. The unit is held forward by the sear 49 which engages behind a plate at the rear of the bufier unit 51, and the timing device is such that after a timed interval the sear is retracted so that the unit may roll back under gravity due to the inclination of the tracks 17 and '18.

Attached to the wheels 15 at a position 52 are flexible ribbons 53 which are carried forward round the part cylinder 31 and, after crossing the path of the apron 16, pass through an aperture in the top of the structure 11 to adjustable anchorages on the structure 11. Preferably these anchorages are spring-tensioned. These bands serve to maintain the apron 16 under tension and also to hold the part cylinder 31 on to the wheels l5. The spring-tensioning of the ribbons allows for small variations in the diameter of the elements 31 and 15.

Thus, when the rolling unit is drawn forward by the handle 46, the end plates 40, cylinders 32, 35 and 3 6, lamp 14 and hood 45 move forward without rotation of any of the parts, the guide rollers 42 moving along the channels 17 and 18, and the wheels 15 roll along the tracks 17 and 18 and cause the part cylinder 31 to roll along the band 16. The edge of the part cylinder 31 is loeated so that when the unit is fully forward it registers with the forward edge 44 of the structure 11.

. Since the apron 16 is secured to the wheels 15 and 43,

the apron is thereby wrapped around the cylinder 31 and accordingly a sheet of light-sensitive material and an original to be copied, if laid on the apron, will be brought into exposure position against the glass cylinder 31 and held there by the apron 16 until the rolling unit is returned, whichwill occur by gravity when the sear a9 is retracted.

When a document-is so copied its trailing edge which is at the forward end of the apparatus is not moved so that the machine enables a page of a book to be copied. The book is placed on the band 50 with the page to be copied lying over the apron 16 the edge 44 being at the fold of the book. Operation of the rolling unit curves the page to be copied round the cylinder 31 but exerts no tension on the page or on the rest of the book, which is therefore unharmed. On the return movement of the rolling unit the page acting as an original and the lightsensitive material are released. The return movement of the unit is controlled by the ribbons 53 and the ten: sion on these and on the apron 16 control the accuracy of roll of the unit.

The lamp 14 is supplied with current via the cable 28 lying in the casing 19 The cable is clamped to the structure 11 and, by a clamp 54, to the skirt of one end plate 40 so that when the trait is rolled back and forth thecable rolls and unrolls freely in the casing 19. The cable 28 passes the plug and socket 55 attached to the block 39 and from 55 heat-resisting insulated wires carry the current to the contacts 38. The wire serving the other end of the lamp passes into plug and socket 56 before reaching the contact 38. It is arranged that the plugs 55 and 56 are accessible through the end plates 40, but the arrangement is such that it is impossible to remove the end plates without first removing the plugs and thus breaking the electrical circuit to the lamp.

A high wattage electric lamp 14 is required to carry out the process for which the apparatus is used. It is therefore necessary to make arrangements for dissipating waste heat and this is achieved by allowing air to flow round all parts of the rolling unit by means of natural convection. To this end, the unit is designed so that at either end of its travel it is open at the top and bottom to allow air to pass freely into and out of the apparatus via the inner surface of the part cylinder 31. a

In order to ensure an adequate and well distributed flow of air, the hood 45 is formed with a duct 57 through,

which air may pass to the inner tubes of the rolling unit.

A baffle 58 mounted on the top of structure 11 is so disposed that when the rolling unit is in its rear position air passing through the duct 57 is partly guided round the rear sides of the tubes in the rolling unit. This baffle 58 also acts as a guide for air passing into the rolling unit via a hole in the top of structure 11 and circulating around the front half of the tubes in the rolling unit. Ducts are also provided in the bottom and finned sides of the end plates 40. i

The forward movement of the rolling unit which rolls the document and copy paper on to the part cylinder of glass 31 also moves that part cylinder into such a position that light'from the lamp 1 falls directly upon all parts of it and is not baffied by the metal cylinder 36.

To ensure even distribution of the light over the Whole of the'surface of the part cylinder 31, the inside surfaces of the cylinder 36 have a light diffusing surface of high reflectivity which is modified locally by the application of non-reflecting paint adjacent to the brightest part of the lamp 14.

Correct exposure of the sensitized material is ensured by the timing device 21 to control the time of exposure. The type of lamp 14 used for the apparatus is not capable of being switched on and off at short intervals and it has therefore been arranged for the copy material and sensitised paper to be released from the machine after sufiicient exposure, the lamp remaining switched on.

At the expiration of the time required to make the desired print, the sear 49 is released and the unit automatically moves to the back of the machine due to the action of gravity carrying it down the sloping top of the structure 11, so removing the document and copy from the action of the light.

A hand release lever 59 is provided so that the rolling unit may be released manually if required.

The timing unit 20, illustrated in detail in Figs. 3 and 4 comprises a plate 61, on which is mounted a bell crank lever 62. One end of the lever 62. constitutes the sear 49 of Figs. 1 and 2 and the other constitutes a release arm 64. The lever 62 is spring-mounted on the pivot 65 so that the lever is urged clockwise on the pivot. The plate 61 further carries a gear wheel 66 which is urged by a spring 67 in clockwise movement. Mounted on the gear wheel 66 is a stud A cover-plate 63 is mounted on gear 66 (shown in Fig. 4) and carries a timing scale 69 and, at the zero index position a stop located in the rotational path of the stud 66. This stop is not illustrated but lies immediately under the figure 0 on the scale.

50 mounted on the plate 61 is a lever 71 pivoted at 72 and projecting at one end 48 beyond the plate. The other end 74 of the lever 71 carries a gear 75 and a constant speed electric motor driving it clockwise. The latter is located behind the gear 75 and is not illustrated. Any good quality small synchronous motor may be employed.

Also mounted on the plate 61 is a hand control lever 76 pivoted at 77 and engaging at its further end with a cam 78, pivoted at 79 and itself engaging with the release arm 64. The pivots 65, 77 and 79, together with a bolt 89, constitute the means whereby the plate 61 is aflixed to the printing apparatus, and the bolt 80 constitutes a stop for the movement of the lever arm 48.

In use the motor is started so that the gear wheel 75 is continuously rotating. The scale 69 is then moved to the required position-say 2 minutes, and locked in position by the wing nut 81. The stop associated with the zero index is thus pre-set and the gear 66 urged by the spring 67 moves around simultaneously (clockwisely), the extent of its movement being limited by the abutment of the stud against the index stop. When the rolling unit of the printing apparatus according to Figs. 1 and 2 is rolled forward into its working position, the butter 22 of same is made to engage with the sear 49 and, at the same time, to move the lever arm 48. Movement of the lever arm 48 brings the gear 75 into engagement with the gear 66 which latter then commences to rotate (anticlockwisely) and will continue to do so untii the stud 60 reaches the lower inclined bearing surface of the release arm 64. By moving the release arm 64 the sear 49 is retracted and the rolling unit rolls away, the timing device then having assumed again its rest position.

If it is required to release the rolling unit before the expiry of the set period, this may be done by depressing the lever '76, thus moving the cam 78 and accordingly the release arm 64 and the sear 49.

it will be appreciated that instead of providing a con tinuously operating motor so that gear 75 rotates even in the position in which it is out of engagement with gear 66, a switching circuit may be incorporated so that depression of the sear 49 or movement of the lever arm 48 closes the circuit to the electric motor and retraction of the sear 49 or countermovement of the lever arm 48 breaks the circuit.

In a modification of the particular construction of the timing unit a single bell-crank lever may be provided to replace elements 62, 49, 64, 65, 76, 77, 78 and 79, pivoted centrally, one end acting as the elements 62, 49, 64 and 65 and the other constituting the element 76.

What we claim is:

In a contact photoprinting apparatus, a rollable exposure member comprising a curved light-pervious panel having an outer surface convex in one direction and straight in the transverse direction, a support providing a track on which said member is rollable bodily to and fro along a path substantially tangent to said surface between a feeding position at a backward part of said track and a working position at a forward part thereof, a flexible apron for applying to said surface sheet material to be exposed through said panel, said apron having a portion held to said surface and having a terminal portion anchored to a forward part of said support so that the apron extends tangentially forward from said surface to said terminal portion to receive sheet material laid thereover, when said member is in feeding position, and is wrapped about said surface by the forward rolling of said member to working position, said track sloping downwardly from said forward part towards said backward part thereof so as to bias said member to roll backwardly to said feeding position under gravity from any location away from that position, releasable locking means at a forward part of said support for holding said member releasably in said working position against the bias of said sloping track, a timing device on said support, and means operated by said timing device after a predetermined period of its operation for releasing said locking means and thus causing said member to roll to said feeding position.

References Cited in the file of this patent UNITED STATES PATENTS 1,894,004 Rose Jan. 10, 1933 2,041,478 Niederle May 19, 1936 2,681,604 Van Der Grinten June 22, 1954 2,681,605 Van Der Grinten June 22, 1954 FOREIGN PATENTS 984,057 France Feb. 21, 1951

Images