Photographic Printer Assembly

The present invention relates to a photographic printer assembly and, more specifically, to a photographic paper and spool assembly for use in the photographic printer assembly.

Commercial photographic printing assemblies process large volumes of negative film by sequentially creating a series of photographic prints in correspondence with a series of negative images. Generally, an enclosure houses a drive system which systematically conveys a web of photographic paper through a printer positioned within the housing. The enclosure is typically opaque to allow the exposure process to occur in a darkened environment. The drive system includes a series of spools and rollers which cooperate to direct the web of photographic paper to and from the printer. More specifically, a feed spool, adapted to retain the unexposed photographic paper in a rolled configuration, and a series of rollers cooperate to direct the unexposed paper along a feed path to the printer. After being exposed in the printer, the photographic paper is guided along a delivery path to a take-up spool which retains the exposed photographic paper in a rolled configuration for further processing.

Typically, the feed and take-up spools comprise cardboard tubes on which the photographic paper is directly wound. Initially, the photographic paper is attached to a feed spool and wound thereon. The feed spool is inserted on a spindle carried by the housing of the printer assembly and the leading edge of the photographic paper is threaded through the feed path, printer and delivery path and affixed to a take-up spool similarly mounted in the assembly. In this manner, the web is attached to both the feed spool and take-up spool prior to the printing process to ensure proper movement of the paper. In use, the drive system incrementally advances the web of photographic paper through the printer. A length of negative film is likewise advanced within the printer, and a series of photographic images are exposed on the previously unexposed photographic paper. The drive system, therefore, also operates to wind the exposed photographic paper on the take-up spool.

Several problems exist with the previously described system. First, rotation of the cardboard spools on the spindles produces dust particles inside the opaque enclosure which can contaminate the photographic negative surface and adversely affect the exposure process. Secondly, the end portions of the web of photographic paper cannot be exposed in the printer since the web is attached directly to both the feed spool and take-up spool. More specifically, a portion of the photographic paper located at the leading end of the web and generally corresponding in length to the length of the delivery path is wasted as it is initially threaded and disposed beyond the exposure stage of the printer. Likewise, a portion of the photographic paper located at the trailing end of the web and generally corresponding in length to the length of the feed path is wasted as it remains along the feed path at the end of the printing process and never reaches the exposure stage of the printer.

The present invention provides a spool assembly of relatively simple and inexpensive construction for use in a printer assembly. The printer assembly includes a web of photographic paper, a printer operative to expose photographic images on portions of the web, and a drive means operative to systematically convey the web through the printer. The spool assembly of the present invention allows substantially the entire web to be exposed by the printer.

According to an important feature of the invention, an extender strip of non-photographic material is attached to one end of the web and cooperates with the drive means to position the portion of the web proximate that end in the printer. This arrangement operates to ensure that the portion of the web proximate the end to which the extender strip is attached is not wasted during the exposure process. The extender strip also provides proper processor drag co-efficient to allow the paper processor normal drying function.

According to a further feature of the invention, a first extender strip is attached to the leading edge of the web and a second extender strip is attached to the trailing edge This arrangement operates to ensure that the both end portions of the web are not wasted in the exposure process.

In the preferred embodiment, an extender strip attached to the leading edge of the web has a length at least as long as the delivery path defined within the printer assembly between the exit of the printer and the take-up spool. This arrangement ensures that the leading portion of the web proximate can be fully positioned within the printer.

In the preferred embodiment, an extender strip attached to the trailing edge of the web has a length at least as long as the feed path defined within the printer assembly between the feed spool and the entrance to the printer. This arrangement ensures that the trailing portion of the web proximate can be fully positioned within the printer.

According to a further feature of the invention, at least one of the spools has a retaining clip mounted on the exterior thereof. This arrangement secures the end of the web, and more particularly the extender strip, to the spool to retain the web in a rolled configuration. In the preferred embodiment, the retaining clip opens in a direction normal to the spool axis and comprises a unitary piece of spring steel formed in a substantially U-shaped configuration.

According to an important feature of the invention, the spool comprises three coaxially aligned portions, wherein the center portion has a diameter less than the diameter of the end portions. The retaining clip is secured on the exterior of the center portion and lies below the surface of the end portions. This arrangement allows the extender strip, which is attached to the retaining clip, to accumulate at the center portion of the spool, and further allows the photographic paper to bear on the end portions without unduly bearing on the retaining clip or extender strip which could damage the surface of the photographic paper.

According to a further feature of the invention, the spool is formed from a rigid plastic material. This arrangement eliminates the dust particles associated with the use of cardboard spools rotatably mounted on spindles in the printer assembly

According to a further feature of the invention, the printer assembly includes a moveable guide means disposed proximate the feed path which is adapted to move between an operative position along the feed path for use in orienting the extender strip on the web in relation to the drive means and an inoperative position removed from the feed path so as not to interfere with the operation of the printer assembly. In the preferred embodiment, the guide means is positioned to be used with an extender strip attached to the leading edge of the web. The guide means operates to ensure that the extender strip is properly oriented parallel with and central to the web so as to prevent damage to the photographic paper due to alignment problems.

According to an important feature of the invention methodology, a portion of a web is exposed in a printer assembly by attaching an extender strip of non-photographic material to one end of the web which cooperates with the drive system to position that end portion of the web in the printer. This method ensures that the portion of the web proximate that end is not wasted in the exposure process.

According to a further feature of the invention methodology, a first extender strip is attached to the leading edge of the web and a second extender strip is attached to the trailing edge of the web. This method ensures that the portions of the web proximate both ends are not wasted in the exposure process.

These and other objects and aspects of the invention will become apparent in the detailed description of the invention hereinafter with respect to the drawings in which:

FIG. 1 is a perspective view of the invention photographic printer assembly;

FIG. 2 is a cross sectional, side view of the invention photographic printer assembly;

FIG. 3 is a perspective view of a paper spool assembly utilized in the invention photographic printer assembly;

FIG. 4 is a fragmentary perspective view of the invention photographic printer assembly; and

FIG. 5 is a plan view of the photographic paper assembly utilized in the invention photographic printer assembly.

The present invention provides a photographic printer assembly 10 which uses spool assemblies of relatively simple and inexpensive construction which allow substantially the entire web of photographic paper to be exposed in the printing process.

With reference to FIGS. 1 and 2, the photographic printer assembly 10 of the present invention includes an opaque housing 11, a photographic paper assembly 12, a printer 14 operative to expose photographic images on portions of the paper assembly 12, a platen 15 operative to position the paper assembly 12 relative the printer 14, a drive means 16 operative to systematically convey the photographic paper assembly 12 through the printer 14, and a guide means 18 operative to initially align the photographic paper assembly 12 in relation to the drive means 16.

The housing 11 typically includes a boxlike main body member 13 and a pivotable door element 19 which allows access to the internal components of the printer assembly 10 while providing a darkened environment during the exposure process. Spindles 44 project in rigid cantalever fashion from the back wall of the body member 13 for engagement with the drive means 16.

With reference also to FIG. 5, the photographic paper assembly 12 includes the web of photographic paper 17, a leading extender strip 20, and a trailing extender strip 22. The paper assembly 12 moves through the printer assembly in the direction of arrow 23. The extender strips 20,22 are reusable and are formed from a non-photographic material, such as mylar, which attach to the web of photographic paper 17 by photographic chemical contaminant-free adhesive tape 24. The adhesive tape 24 is preferably chemically neutral so as not to interact with emulsion side of the web of photographic paper 17. The metal clip with one full wrap (360 degrees) of the extender strip 22 will withstand the torque created in the normal printer paper drive.

The drive system 16 is divided into two operative sections: a feed assembly 26 operative to deliver the unexposed photographic paper web 17 to the printer 14, and a take-up assembly 28 operative to receive the web 17 after being exposed by the printer 14. The feed assembly 26 includes a feed spool assembly 30, a pair of tensioning rollers 32, and a metering drive roller 34. The take-up assembly 28 includes a secondary drive roller 36, a pair of tensioning rollers 32, and a take-up spool assembly 38.

With reference also to FIG. 3, the feed spool assembly 30 includes a spool 40 and retaining clip 42. The spool 40 comprises a substantially cylindrical tube formed from a rigid plastic material and having three coaxially aligned portions 40A, 40B, 40C. Portions 40A, 40C are positioned at the ends of the spool and preferably have a diameter of approximately 1 inch, and the center portion 40B has a diameter less than the 1 inch diameter of the end portions 40A, 40C. This difference in diameters produces an annular trough which corresponds to center portion 40B wherein the extender strip 22 is wound. The inner diameter of the trough is defined by the outer diameter of middle portion 40B, and the outer diameter of the trough is defined by the outer diameter of end portions 40A, 40C. A substantially U-shaped retaining clip 42 formed from a piece of spring steel is secured to the exterior of the center portion 40B so that the outwardmost surface of the retaining clip 42 lies below the outwardmost surface of the end portions 40A, 40C. The retaining clip is oriented to open in a direction normal to the spool axis so as to allow the trailing extender strip 22 to engage the retaining clip 42 and roll around the relatively narrow center portion 40B of the feed spool 40. The web of photographic paper 17 will then bear on the exterior of end portions 40A, 40C without unduly bearing on the retaining clip 42 or previously wound trailing extender strip 22. In fact, the trailing extender strip 22 typically fills the annular trough of center portion 40B, such that a relatively uniform surface having a diameter substantially the same as end portions 40A, 40C is formed. In this manner,. the web 17 will evenly bear on the exterior of end portions 40A, 40C and the previously wound extender strip 22 on center portion 40B.

The feed spool 40 is adapted to engage the drive system 16 and is typically disposed on a spindle 44 for rotational motion about the spool axis. The feed assembly 26 operates to direct the web of photographic paper 17 from the feed spool 40 along a feed path to the printer 14. Tensioning rollers 32 are carried by the housing 11 and are positioned along the feed path to provide sufficient tension to the portion of the web of photographic paper 17 so that metering drive roller 34 also mounted in the housing 11 may advance the web 17 using to the frictional engagement of the web 17 thereon. The web of photographic paper 17 is thereby controllably advanced at predetermined known increments during the exposure process.

The take-up assembly 28 operates to direct the exposed web of photographic paper 17 from the printer 14 along a delivery path to the take-up spool assembly 38. The take-up spool assembly 38 includes a take-up spool 43 and retaining clip 42. The spool 43 is constructed similarly to the feed spool 30, so as to include a retaining clip 42 and is operative to engage the leading end of the leading extender strip 20 and wind the exposed photographic paper 12 thereon. Further, the take-up spool 43 is also disposed on a spindle 44. Tensioning rollers 32, carried by the housing 11 and positioned along the delivery path, support the portion of the web of photographic paper 17 to provide sufficient tension for operation of secondary drive roller 36 mounted on the housing 11 and to insure that the exposed paper 17 is properly wound on the take-up spool 43. The exposed web of photographic paper 17 is retained in a rolled configuration thereon for further processing

With reference also to FIG. 4, the guide means 18 is disposed proximate the feed path and includes a base plate 46 and a guide plate 48 pivotably interconnected by hinge 50. The guide plate 48 includes a planar portion 47 and a pair of upwardly extending side portions 49 attached at opposite sides of the planar portion 47.

The base plate 48 attaches to the floor of the housing 11 and allows the guide plate 48 to pivot about the axis of hinge 50. The guide plate 48 is adapted to move between a raised operative position 48A along the feed path for use in orienting the leading extender strip 20 on the web 17 in relation to the drive means 16 and a lowered inoperative position 48B removed from the feed path so as not to interfere with the operation of the printer assembly. The guide means 18 is further positioned within the housing 11 so that a path defined across the top of the guide plate 48 between the upwardly extending side portions 49 when the upper plate 48 is disposed in its raised operative position 48A lies along a central portion of the feed path. Thus, the guide 16 automatically provides the means to ensure that the extender strip 20 is properly oriented on the web 17 to maintain the alignment of the web 17 in relation to the drive means 16 by placing the extender strip on the guide plate 48. This prevents damage to the photographic paper 17 during operation of the printer assembly due to misalignment with the apparatus.

In operation, the present invention uses the following method of exposing the web of photographic paper 17 in a printer assembly 10. A leading extender strip 20 is attached to the leading edge of the web of photographic paper 17 and has a length at least as long as the delivery path of the take-up assembly 28. A trailing extender strip 22 is attached to the trailing edge of the web of photographic paper 17 and has a length at least as long as the feed path of the feed assembly 26. Thus, the web of photographic paper 17 and the extender strips 20,22 form a photographic paper assembly 12 which is wound on the feed spool 40. The feed spool 40 and take-up spool 43 are positioned in the printer assembly on spindles 44, and the photographic paper assembly 12 is unwound from the feed spool 40, threaded through the feed path, printer 14 and delivery path, and the leading end of the leading extender strip 20 is attached to the retaining clip 42 on the take-up spool 43 so as to position the leading edge of the photographic paper 17 proximate the printer 14. In operation, the web 17 is incrementally advanced through the printer assembly by coordinated operation of drive roller 34 and secondary drive roller 36 to sequentially expose portions of the photographic paper 17 to film in the printer 14 until the trailing edge of the photographic paper 17 is positioned proximate the entrance to the printer 14 and the trailing extender strip 22 extends from the printer 14 to the feed spool 40 along the feed path. In this manner substantially all of the web of photographic paper 17 may be exposed in the printer 14.

The guide means 18 is utilized during the step of threading the paper assembly 12 through the apparatus to align the attachment of at least the leading extender strip 20 to the web of photographic paper 17 by positioning the guide plate 48 in its operative position 48A in proximity to the feed path. Prior to threading the paper assembly 12 through the assembly, the leading extender strip 20 is positioned on the guide plate 48 between the upwardly extending members 49 so as to position the leading extender strip 20 substantially parallel with the web 17. Therefore, alignment of the web 17 in the drive means 16 is not disturbed by misalignment of the extender strip.

From the foregoing description of the preferred embodiment it can be seen that various alternative embodiments of the invention can be anticipated without departure from the scope of the invention as defined in the following claims.