WO1998006588A1

WO1998006588A1 - Recording assembly for ink-jet printing and transparencies

Info

Publication number: WO1998006588A1
Application number: PCT/US1996/013425
Authority: WO
Inventors: Alan J. H. Herbert; Virtudes R. Lund; James B. Svacha
Original assignee: Minnesota Mining And Manufacturing Company
Priority date: 1996-08-12
Filing date: 1996-08-12
Publication date: 1998-02-19
Also published as: AU7008496A

Abstract

An improved transparency recording assembly for use with ink jet printers includes a sheet of transparency film having two major surfaces and two longitudinal side edges connected by shorter side edges. The film has an imaging area for accepting an image intended for projection by an overhead projector. An opaque flap is attached in a foldable manner adjacent a side edge of the film, with the folded position being that position wherein the flap covers at least a portion of the imaging area. In use, the flap is in an unfolded position and blocks light which would otherwise shine past the edges of the transparency. An indicia having predetermined optical characteristics is placed on the flap to override predetermined printer functions and improve image quality on the transparency film.

Description

RECORDING ASSEMBLY FOR INK-JET PRINTING AND TRANSPARENCIES

BACKGROUND OF THE INVENTION

The present invention relates to films having an image thereon (transparencies) for use with overhead projectors.

In particular, the present invention relates to an improved light-blocking transparency assembly that is imageable in an ink jet printer or the like.

Transparencies are transparent or translucent films that may be clear or colored and include textual or graphical data. The data on the transparency may be projected on a distant surface or screen, usually m enlarged form, by an overhead projector so that the data may be observed by a large number of people at once. A typical overhead projector includes a stage upon which the transparency may be placed and light form a source within the projector is directed through the stage and the transparency to a lens system which focuses the light, and an image of the data contained on the transparency, on the distant viewing surface.

The transparency is most conveniently produced today by the use of a sheet of polymeric film which can be imaged in electrographic or xerographic imaging processes, or devices such as ink et printers, thermal mass transfer printers or plotters employing other imaging means. The transparency is typically the size of standard letter paper while the stage is of a greater size to accommodate a variety of different possible transparency sizes. Usually, this results in light beyond the edges of the transparency being projected to the screen along with the data contained on the transparency. This situation is not a great problem if the transparency is clear, but if the transparency is colored or translucent, the white light projected from those areas beyond the edges of the transparency is very distracting to the audience. U.S. Patent No. 4,402,585 describes a rectangular envelope which has folding flaps attached to two opposed edges. In use, the transparency is placed within the envelop and the flaps extended to block the light which would otherwise shine past the edges of the transparency, thereby limiting light transmission to the distant viewing surface to that passing through the transparency. The envelopes work very well, but have the disadvantage that the light must pass through three layers of film, including two comprising the envelope and the transparency itself, which affects the brightness and clarity of the projected image. In addition, the envelope/transparency combination results in a somewhat bulky package.

U.S. Patent No. 5,319,400 describes a light-blocking transparency assembly which has a rectangular sheet of transparency film directly imageable by machines employing electrographic or xerographic imaging processes, or devices such as ink et printers, thermal mass transfer printers or plotters employing other imaging means. The light blocking transparency assembly includes at least one opaque flap attached in a foldable manner to the film, with the folded position being that position wherein the flap extends from its attachment edge to the sheet toward the larger portion of the sheet. The entire transparency assembly is capable of passage through the electrographic, xerographic, ink jet printers or other imaging means .

In use, the transparency is placed on the stage of the overhead projector and the flap extended to block the light which would otherwise shine past the edges of the transparency. In this fashion, light transmission to the distant viewing surface is limited to that passing through the transparency. The transparency assemblies of U.S. Patent No. 5,319,400 have proven very successful in that they require the light to pass only through one layer of film (the transparency itself), thereby improving the brightness and clarity of the projected image. In addition, the assembly is less bulky than the envelope assembly of U.S. Patent No. 4,402,585.

Light blocking transparencies such as those described in U.S. Patent No. 5,319,400 may be printed, for example, m ink jet printers. Certain printers have devices incorporated in their feed paths that sense the nature of the recording sheet being fed into the printer (e.g., whether the recording sheet is transparent or opaque) . The printer sensors typically include a radiation source for directing radiation of a known wavelength onto the recording sheet, and a detection device for measuring the amount of radiation reflected from the recording sheet. Depending upon the amount of reflected radiation measured by the sensor, the printer determines whether the recording sheet is transparent or opaque. This information regarding the nature of the recording sheet is then used to control various printer functions, such as the amount of ink to be deposited per unit area on the recording sheet. This is done for a number of reasons, including to avoid excess use of ink, to correct for any operator error in setting up the printer functions, and to ensure that the best image possible is produced.

In the example of opaque recording sheets and transparent recording sheets, the amount of ink deposited per unit area on the page is important to the quality of the image produced. In particular, when compared to an image created on an opaque recording sheet, a transparency image requires a greater amount of ink be deposited per unit area, so that an intense and vibrant image will be projected onto the distant viewing surface. Typically, a lesser amount of ink per unit area is required to produce a high quality image on an opaque recording sheet. When the printer is unable to distinguish between opaque and transparent recording sheets, incorrect amounts of ink may be deposited on the recording sheet, and the resulting image quality may suffer as a result.

In certain recording sheets, such as the transparency assembly described in U.S. Patent No. 5,319,400, and m other recording sheets where, for quality reasons, high ink loadings are needed, the automated function of the printer must be temporarily disabled or overridden. The automated function must be disabled or overridden because the detection device of the printer will sense an opaque recording sheet and cause a lesser quantity of ink to be deposited on the recording sheet than is required for a high quality image. In the example of the transparency assembly described m U.S. Patent No. 5,319,400, the opaque flap attached to the transparency film will cause the printer to function as if an opaque recording sheet is being fed into the printer, and an inadequate amount of ink will be deposited per unit area on the transparency film. The result is an image which is not of the highest possible quality. A need thus exits for a manner in which to disable or override the automated printer functions in those instances where the automated functions do not produce the desired image output.

SUMMARY OF THE INVENTION

The present invention provides an improved transparency recording assembly for use with ink jet printers. The transparency recording assembly of the present invention includes an indicia having predetermined optical characteristics which allows the printer operator to override or disable automated printer functions to achieve the output desired by the operator. The transparency recording assembly includes a sheet of transparency film having two major surfaces and two longitudinal side edges connected by shorter side edges. The film has an imaging area for accepting an image intended for projection by an overhead projector. An opaque flap is attached in a foldable manner adjacent a side edge of the film, with the folded position being that position wherein the flap covers at least a portion of the imaging area. In use, the flap is in an unfolded position and blocks light which would otherwise shine past the edges of the transparency. The indicia having predetermined optical characteristics is placed on the flap m a position to intercept printer sensors and override predetermined printer functions controlled by the sensors.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described with respect to the accompanying drawings, wherein like numbers refer to like parts in the several views, and wherein:

FIG. 1 is an elevational view of a light-blocking transparency assembly according to the present invention;

FIG. 2 is a plan view of the transparency assembly of FIG. 1, along the direction of lines 2-2 in FIG. 1; and

FIG. 3 is a perspective view of the transparency assembly of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION The present invention is discussed with reference to transparent recording sheets imaged m an ink jet printer. However, the invention is equally applicable to other types of recording sheets which would benefit from the ability to disable or override an automated printer function. Likewise, the invention is also applicable to other types of imaging devices which utilize a recording sheet detection mechanism to automate various functions of the imaging device .

A light-blocking transparency assembly 10 is illustrated in FIG. 1 and FIG. 2. The transparency assembly 10 is like that described in co-owned U.S. Patent No. 5,319,400, which is herein incorporated by reference. Transparency assembly 10 includes a film substrate 12 coated at least on one side (coating on both sides is illustrated) by an imaging coating 14, preferably including a copolymer and a polymeric particulate as described m U.S. Patent No. 5,319,400. Attached to substrate 12 by means of hinges 16 and 18 are light-blocking flaps 20 and 22. Opaque, substantially rectangular flaps 20, 22 are attached in a foldable manner adjacent the outer longitudinal edges of substrate 12. Flaps 20, 22 are preferably made from a material which accepts text written by conventional writing instruments, so that the user can write notes on flaps 20, 22 which are visible to the user but not to the viewing audience. Flaps 20, 22 are attached to substrate 12 by hinges 16, 18 which may be flexible adhesive tapes of such materials as woven or non-woven fabrics or polymers coated with adhesives, preferably pressure sensitive adhesives. If the material of hinges 16,18 is a suitable polymer, hinges 16,18 may be attached to flaps 20,22 and substrate 12 by means such as heat sealing, sonic welding, solvent welding or heat welding. Of course, flaps 20,22 can be connected to substrate 12 in any other manner provided that it produces a hinge effect.

Although flaps 20, 22 may be attached to the extreme edges of substrate 12, it is preferred that flaps 20,22 by attached inwardly of the edges of substrate 12. The purpose of flaps 20, 22 is to block light produced by the overhead projector which would otherwise shine past the edges of the transparency to be projected on the viewing screen. If the transparency were clear ( m that it was not colored) , light shining past its edges would not be objectionable. If, however, the transparency is tinted with a color, or was less than entirely transparent, the light shining past its edges would cause a bright, white border which could be very distracting to the viewing audience. Flaps 20, 22 are designed to be used as shown in FIG. 3 to block light from shining past the longitudinal edges of the transparency.

Flaps 20, 22 are attached inwardly from the edges of the substrate 12 to ensure that no light escapes beyond the edges of substrate 12. Particularly if substrate 12 is provided with holes 24 for storage of the transparency assembly 10 in a binder or the like, the position of flap 20 or 22 adjacent holes 24 is critical. As will be clear from the Figures, flap 20 (at the side edge of substrate 12 which is provided with holes 24) must be spaced from the edge of substrate 12 so that holes 24 are exposed in the folded state of flaps 20, 22 to permit storage of transparency assembly 10 m a binder or the like. In the unfolded state, flap 20 covers holes 24 so that they are not projected onto the screen during a presentation.

Best seen m FIG. 2, at least one of flaps 20, 22 is provided with a marking or indicia 30 designed to disable or override an automated printer function. In this example, indicia 30 is shown on flap 22. The indicia 30 deceives or disables sensors in the printer which determine whether the recording sheet being fed into the printer is transparent or opaque, thereby causing the printer to operate in the manner desired by the operator. The indicia 30 may be created by the direct application of paint or ink to the recording sheet, or by a removable patch placed on the recording sheet. When the printer sensor detects the arrival of a recording sheet and commands the print cycle to start, the arrival of the indicia 30 overrides or disables the particular printer function in the manner desired by the operator.

In the particular example illustrated herein, it is desired to print in what is known as "transparency" mode, on a transparency recording sheet (like that described above and m U.S. Patent No. 5,319,400) which appears to the viewer, and to the printer, as an opaque substrate (due to opaque flaps 20, 22). "Transparency" mode prints a greater quantity of ink per unit area than "opaque" mode. At noted above, transparencies printed in opaque mode have less saturated colors, and lower optical densities (i.e., lower image quality) . The ability to print m "transparency" mode on an opaque substrate is also useful for recording sheets other than transparencies. For example, opaque recording sheets generally described as "high quality substrates" may have significantly better appearing images if a greater quantity of ink is printed per un t area on the substrate. In practice, the optimum position and size for the indicia 30 is selected based on the particular type of imaging device m which the recording sheet is to be used. The mark or indicia is then made at the selected position. Typically, it is found that the most desirable position for the indicia 30 is near (but not contiguous with) a leading edge of the recording sheet. Thus, interference with the actual image is minimal or non-existent. In the case of the transparency assembly 10 described above and shown in the Figures, the indicia 30 is not physically on the substrate 12 which receives the image, but rather is on one of flaps 20, 22 and only visible though the transparency substrate 12. The indicia 30 thus will not impact the image on substrate 12 at all.

The indicia 30 possesses sufficiently different optical characteristics to those of the surrounding recording sheet to enable the imaging device sensor to respond to the indicia's appearance. Of course, the specifications for indicia 30 and its position will vary according to the printer model, and also to some extent between nominally identical printers. The indicia 30 specification must thus be written so as to ensure that all printers of the same type respond to the indicia. This is achieved by ensuring that the minimum density of the indicia 30 is reliably higher than that density needed to trigger all detectors of a particular printer type. A certain minimum density, at a defined radiation wavelength, is typically sufficient to achieve the desired result. For example, in the case of a detection device operating at 800nm wavelength, an indicia 30 reflecting only half of the incident radiation may be effective. By reflecting only approximately half of the incident radiation, it appears to the imaging device that the recording sheet is transparent, and "transparency" mode is thus used when printing the image . Typically, the indicia 30 will be permanently placed on the recording sheet using an ink having the desired optical characteristics. Alternatively, instead of an ink mark, the indicia could be, for example, a material that redirects the incident radiation away from the sensor. Particularly, mirror-reflective indicia may be used, or indicia material that redirect radiation back to the source

(and not to the sensor) . These may have advantages in being less visually obtrusive than an ink mark on the recording sheet. For example, if the sensor is responsive to infrared radiation, indicia may be used that do not absorb in the visible region but which contain infrared absorbing dyes. Such indicia would be invisible or very unobtrusive to the human eye.

In certain cases, particularly where a recording sheet is opaque m its final application, it is desirable to make the indicia removable, and the use of a permanent indicia (as formed by ink and the like) on the recording sheet is not aesthetically acceptable. A removable or temporary indicia may be created by attaching removable tape patches to the recording sheet, the tape patch having the proper reflection or absorption characteristics on one surface of the tape, and a pressure-sensitive adhesive on the opposite surface of the tape.

EX.ΑMPLE

The following example is provided to demonstrate the value of the indicia as used with a transparency recording sheet. In the example, four samples were fed through a Hewlett Packard Desk Jet 1200C printer to generate test patterns of four colors (black, cyan, magenta and yellow) . The optical densities of each color in the test patterns were then measured to the appropriate color of light using a Macbeth TD 903 Densitometer . The data in Table 1 below was obtained from the samples as indicated. The samples were as follows:

Sample 1: 3M Ink Jet film type 3460, standard, with a paper stripe on the leading edge. Although the paper stripe on the leading edge is opaque, this sample is recognized by the printer as a transparency, and accordingly the printer' s

"transparency" mode is used. The purpose of the paper stripe is to signal the printer that a recording sheet is being fed into the printer.

Without the opaque paper stripe, a transparency cannot be seen by the printer. If the width of the stripe exceeds about 15-20mm the transparent film is treated identically to an opaque recording sheet. Sample 1 served as the

"control" specimen. Sample 2 : Film with opaque flaps attached to the transparency film, but no indicia. The Sample comprised a light-blocking transparency assembly like that described m U.S. Patent No. 5,319,400, commercially available from Minnesota Mining and Manufacturing Company. The opaque flaps cover essentially the entire "back" side surface of the transparency film, thereby causing the printer to treat the transparency assembly as an opaque recording sheet. Sample 3(a): Film with flaps (as in Sample 2), with indicia, run at the start of the experiment. As illustrated in FIG. 2 and FIG. 3, the indicia 30 was positioned on the opaque flap such that the indicia 30 was visible through the transparency film and in the proper position to be detected by the printer sensor. The indicia 30 overrode the printer' s sensor and caused the printer to print on the opaque transparency assembly as though is were transparent. Sample 3(b): Film identical in composition to Sample 3(a), but run last in the experiment

The Samples 2, 3(a) and 3(b) each used the same type k jet transparency film as Sample 1.

T.ABLE 1

Patch Color

Black Cyan Magenta Yellow

(to white (to red (to green (to blue light) light) light) light)

Sample 1 2.69 1.75 1.17 1.21

Sample 2 2.46 0.86 0.54 0.64

Sample 3(a) 2.29 1.65 1.11 1.16

Sample 3(b) 2.71 1.97 1.20 1.32

It can be seen from the data in Table 1 that Samples 3(a) and 3(b) are similar in density to Sample 1, and Samples 1, 3(a) and 3(b) are markedly superior m color densities when compared to Sample 2. The data make clear that the indicia 30 on the transparency assembly (Samples 3(a) and 3(b)) successfully overrides the printer sensor and cause opaque recording media (i.e., the transparency film with opaque flaps) to be printed upon m the "transparency" mode. The resulting optical densities are far higher than when the indicia is not used and the printer applies the lower ink needed for opaque recording sheets (Sample 2) . Clearly, the indicia of the present invention improves the quality of images produced on the light-blocking transparency assemblies of U.S. Patent No. 5,319, 400.

Although the present invention is discussed w th reference to transparency assemblies and transparent recording sheets imaged m an ink jet printer, those skilled in the art will recognize the invention is equally applicable to other types of recording sheets which would benefit from the ability to disable or override an automated printer function. Likewise, the invention is also applicable to other types of imaging devices which utilize a recording sheet detection mechanism to automate various functions of the imaging device.

Claims

WHAT IS CLAIMED IS:

1. .An improved light-blocking overhead transparency assembly for use with a printer, the improved transparency assembly comprising: a single substantially rectangular sheet of transparency film having two major surfaces and two longitudinal side edges connected by shorter side edges; an imaging coating covering substantially all of at least one major surface of the transparency film and defining an imaging area, the imaging coating being capable of accepting an image intended for projection by an overhead projector; at least one opaque flap attached in a foldable manner adjacent a side edge of the film, with the folded position being that position wherein the flap covers at least a portion of the imaging area; and an indicia having predetermined optical properties positioned on the opaque flap for overriding predetermined printer functions.

2. The improved transparency assembly of claim 1, wherein the optical characteristics of the indicia causes the printer to print in transparency mode.

3. The improved transparency assembly of claim 1, wherein the indicia is radiation absorptive.

4. The improved transparency assembly of claim 1, wherein the indicia is mirror-reflective.

5. The improved transparency assembly of claim 1, wherein the indicia is removably secured to the flap.

6. The improved transparency assembly of claim 5, wherein the indicia is removably secured to the flap by a pressure sensitive adhesive.

7. The improved transparency assembly of claim 1, wherein the flap is spaced from the longitudinal edge of the film such that in the unfolded position the flap covers the longitudinal edge of the film and in the folded position the flap exposes the longitudinal edge.

8. The improved transparency assembly of claim 1, including two flaps, one of which is attached adjacent each longitudinal edge of the sheet.

9. The improved transparency assembly of claim 8, wherein the flaps substantially abut each other in the folded position.

10. The improved transparency assembly of claim 9, wherein at least one of the flaps is spaced from its associated longitudinal edge of the film such that in the unfolded position the flap covers the longitudinal edge of the film and in the folded position the flap exposes the longitudinal edge.