FR2650409A1 - Device for aiding the photocopying of books - Google Patents

Abstract

The invention relates to a ruler (straight edge) intended to be placed between the book and the glass pane of the photocopying machine, under the hinge (binding), in order to fill in the space located there so as to eliminate the blurring and the dark bar which normally form there. It consists of at least one mass of transparent material having a refractive index which is markedly greater than that air. Its profile is largely that of a roof with gentle slopes. It comprises a means for wedging it in the hinge of the book and, in particular, acts by pushing back the extreme limit of clarity of machines for copying.

Description

 The invention relates to the field of daily life and perhaps 8 will be judged thus, also to the field of optics.

 Specifically, it concerns the photocopying of books.

We believe that the state of the art on the subject will be complete if we consider three categories of objects:
- Copying machines
-The prisms
-The rules
To these three categories, it is also necessary to add the patent application 88 06 386 "Structure composed of light guides having the shape of a plate of particular section. N
Photocopying machines are nowadays equipped with devices for erasing dark areas.

-brown or black (areas 2,4,4 fig I) which result from the lack of light caused by losses due to the separation of the reflective surfaces which are the pages and the back of the cover of the photocopiers , from the machine window. (21.22 fig 2)
The process in question is quite effective and photocopying when the machine has been previously placed in the book position is no longer marked by these areas. However, a problem remains in full: the text too close to the hinge , especially for thick books, illegible in part because of the curvature (20 fig 2) of the pages, but also of its distance from the plane of the glass, which makes it blurry, cannot title reproduced because the device does than white - shuffle the paper around the central hinge and delete the text at the same time.

Other copying machines have been redesigned so that books can be placed on the glass, so that the space under hinge (21 fig 2) is reduced or even canceled (fig 3). the glass (5) is then faithfully reproduced, the dark bar around the hinge is also removed, but not the dark zone around the book (zone I figIj I1 there is above all a drawback which remains: one cannot reproduce only one of the two pages of the open book at once. As many of the books are small enough to hold open entirely in format
At 4, and that there is always the resource for larger works of using a format adapted to their size in order to reproduce two pages of these large formats at once, the impossibility of doing so is a real one. handicap for the user.

-The prisms
They are used in a large number of devices, in various huts, polarization, stickers, reflection, deviation according to determined angles, decomposition, of light.

 Among them, a prism this Bauerfeind concerns us because one of its angles has a value of 22.50. However the use of this prism supposes a metallic face and the prism is not straight. In addition we often cut the edge corresponding to this low value an -gle because it is considered useless. It cannot therefore be an anteriority for our object which absolutely needs to keep its acute angle.

-The rules
Whatever their form, the rules are not known to us, not used for their optical properties, or if these properties exist, they are used as such separately from the other characteristics of the rule where they are found.

 our own patent application Ralle also concerns us as a prior art possislecar its main applicatitn was also the aid for photocopying deli- -vres.This is a kind of strip made up mainly -ment '' a plate of short otic fibers, assembled by -alleles between them and joining the faces of entry and exit of the light intended to transfer anointed by point an-image without displacement or deformation of any kind.This may seem interesting but, it has very real drawbacks.

 It does not allow the two pages of an open book to be photocopied simultaneously (nor would it allow this if two were mirrored, because at the top a gap would remain and the text at this location could not be reproduced. ).

 The beveled trill of the plate is very delicate and at low angles the fragility of the assembly, especially near the ends, makes it difficult to manufacture; the space (7 fig 4) becomes very difficult to re-take.

 Alignment, bonding is complex, the fibers are so expensive to buy that the only coding material prohibits any commercialization, and their manufacture even only for our application that does not require a high quality, is complex, long costly and delicate.

 The sharpness of the transmitted image risks being af -fected by an insufficient resolution, mediates with a diameter of the fibers of 160 microns.

 The present invention which does not have these drawbacks is therefore a clear progress both from the point of view of performance and that of manufacturing.

In summary. I1 does not currently exist a device for photocopying books under the following conditions carried out simultaneously:
Possibility of reproducing the two pages of an open book without zone or dark bar along the hinge of the book, without risk of illegibility of the text by blurring or curvature of the pages when the book is thick or printed too close to its hinge , also without risk of text erasure, all thanks to a simple device, inexpensive and easy to manufacture.

 This problem of reproduction is solved for the first time, thanks mainly to the transposition of prisms from the optical domain into that of daily life to modifications of the profile of the oblique faces of the prisms, constituting significant improvements with respect to the state of the technique, with the particular values of the angles of these prisms and their dimensions, so that their optical and mechanical properties are compatible and used simultaneously.The presence of a plate constituting a wedge pin located in the central longitudinal plane, playing at the same time an optical role and a mechanical role is a simple but important addition.

The device according to the invention is a rule consisting mainly of at least one mass of transparent material, the absolute refractive index of which is significantly greater than that of air, with lateral transverse profile.

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either in a dihedral shape, or in an arc-of-a-circle shape, determined maximum height rule, at base angles with a value between 200 and 250 and whose role is both to push back the extreme limit of sharpness of the objective of copying and constraining machines by helping to press them against itself, the pages of books, respecting their natural tendency to bend, role whose purpose is to fill in the gaps (21 fig 2 and Q and 8 fig 4 a) and transmit a clear raised text.

 - Optical reasons for the characteristics of the rule and characteristics resulting therefrom.

The transparent material, thanks to its refractive index, has the effect of modifying the path of the light rays coming from a source located inside the machine and exiting through the glass. external and extreme limit of sharpness of the objective of the machines then passes from 2-3 mm above the glass to approximately I2mm, for a certain material. According to the machines and the objectives the limit in cues -tion can vary. 'is pou ~ quci we can ia determine with the help of the following method :: it suffices for this to photocopy a book page. Referring to Figure 4 we understand how to proceed. 0n starts with noicir l edge of the prism on the side of the angle &alpha; , we photocopy a book after having placed it on the prism (fig 4 a), we then measure on the copy (fig a b) the distance D between the black line identifying the edge of the angle &alpha; and the horizontal sharpness limit IO. By raising the hortogonal at the base of the prism from the IO limit, we obtain a height yz (i.e. h fig ea) which is the maximum height at -orized for the masses of transparent material of the object itself.

The requirement of readability of the text even when it is clear leads to limit to 250 the value at the angle n effect the pro section on the horizontal, on the surface of a page following the oblique side of the rule is eg AI 'on AI (fig 5) equal to cos &alpha; or cos 250 N 0.9. The text will therefore undergo thanks to this limitation a contraction along the axis of the lines which will never exceed IO%. This seems to us to be a good criterion for a read even easier. other realization than ours which calls into question this criterion of maximum contraction, obviously would not depart from the framework of the invention, because if the text still remained readable although more difficult, there would follow no progress, this would even be a regression.

 - Mechanical reasons for the characteristics of the rule and characteristics resulting therefrom.

In Figure 2 we see at 21 that a book placed upside down on the glass of a photocopier delimits a space that the rule seeks precisely to fill. The rule must therefore have a height of IO mm minimum, because otherwise it becomes as difficult to photocopy the book as without a rule because it is necessary to exert too strong pressure on the edge on the back of the book. The consequence which follows is that the angleokne can not have a value too low, because then its width would be too large.

 In Figures 5 and 8 we can see (25 fig 5) a lug used to wedge the ruler in the hinge so that said ruler is well in ltaxe of the same hinge, because although it does not seem eviaent without this wedging lug , the ruler slides over the pages and can go awry.

In one embodiment, said lug is the end of a white plate (I2 fig 5,6,7,6) whose role is also optical:
-reference against the surface of the page, of certain rays (26 fig 5)
- send down, with light to hide the black stripe at the bottom of the hinge, on the photoco-pictures.

Let us now see detailed realizations of the object according to the invention
Figure I: represents a photocopy of a book without any special adaptation to photocopying.

Figure 2: is a view, flush with the glass, in the axis of the hinge, of an open book, explaining the reason for the black areas.

Figure 3: is a side view flush with the glass, in the axis of the hinge, of a book photocopied on a machine designed according to a recent development.

Figure 4: (a) is a view flush with the glass in the axis of the hinge in the photocopying position when a prism is placed under the book (the prism is very magnified)
(b) is a bird's-eye view of a photo-copy part obtained under the conditions of FIG. 4 (a).

Figure 5: is a side view of an "biprismatic" embodiment of the object according to the invention.

Figure 6: is a side view of the improvement "dihedral"
Figure 7: is a side view of the improvement "arc of a circle"
Figure 8: is a side view, enlarged, of the end of the central plate showing the shape of the wedge pin.

Figure 9: is a side view, enlarged, of the edges of the two improvements, showing how we can finish these edges.

Realization of the simple Dlus:
In Figure 4 a volt is placed a book placed on a prism without particular pressure. We then notice the zones 7 and 8 of non-contact between the pages and the prism. Using a simple prism therefore seems of little use. However if the press both on the back of the book at 27 and on the pages at 28 the photocopy is of good quality.That is why a rule composed of two prisms separated by a white plate (I2), the two straight prisms (II) accots by their short side of the right-angle to said plate, can be used anyway, thanks to the low value of the angle aid 200. The material used is polymethyl methacrylate (PMMA), the height "maximum optical" and that retained is h = I2 mm.

 The central plate (I2) is white, made of plastic, but it is not compulsory, 13.5 mm high.

As FIG. 8 shows, its end I3 is rounded and its outer sides (I4) with prisms, inclined.

The two improvements which follow are made in the same materials, their height h is the same as above. They have been constructed geometrically from basic pri -sms as we can already see in Figures 6 and W
The "dihedral" refurbishment
Figure 6
To prevent the existence of the void 7 (fig 4 a), the prisms AII ′ and I ′ IA ′ of angle 9 = 20 have been extended by means of a break in slope causing the ends of the oblique faces to make an angle of vertex B or B '(angles &alpha;;') of IO respecting a minimum value of the distance d (AB or A'-B ') of IO mm. This corresponds to the angle and the distance with which and to which the pages make contact with the glass after having been tilted at an angle of 200 relative to it.

Thanks to this improvement there is no longer any pressing on the sheets but only on the back of the book.
But as the reduction of space ((8) fig 4 a) requires that lton presses on the book with a certain force, one can still improve the device.

This is the "arc of hooping" without this realization the faces CJ and C'J (fig 7) are curved according to an arc of a circle tangent both to J (vertex of the prisms) to the face AJ or A 'J of the base prism (I in dotted line) and in C or C' on the horizontal surface of the .ri- -tre of the copying machine. The radius R is evienent perpendicular to the faces AJ or A'J and has for value
R = h / (2 sin &alpha; / 2). In this case, we will take for its maximum value -mum of 250, otherwise, as ha a value of I2 mm and that it is better not to decrease it, the total width CC 'would be too large and the object would be bulky.

 It will be noted that the radius thus defined is the smallest respecting the requirement of maximum slope at 250.

It will also be noted that the end
C or C 'of the curve is theoretical and that in reality, it will be necessary, as for the previous improvement, to truncate the arate of the object, so that it retains its solidity, but we will think of shortening said edge in gentle slope (see I5 fig 9)
The value of the radii for h = I2 mm, is approximately I28 mm
The width CC ′ is approximately 110 mm.

 The length of all the rules shown above can of course vary; a value to choose is that of the width of the glass of many copying machines, ie 30 cm.

Concerning the manufacturing several techniques are possible
Extrusion, plate machining, molding.

The first can undoubtedly be used to obtain triangular prisms with &alpha; = 20. However the extremity of the edges is likely to come out badly which is why we will prefer the use of plates. The great advantage of molding is that it would make it possible to obtain rules in one piece. The wedging pin would no longer be a vertical white plate, since it could be an integral part of the masses of my material. It will then be necessary to groove the underside of the ruler longudinally, to dye the groove (which is a hollow) in white without this white being in contact with the glass and disappearing during use.

Claims (9)

 PtVENDI CÂTIONS  - significantly higher than that of air.  consists of a rule comprising at least one mass of transparent material whose refractive index is signi  I) Photocopying aid device, characterized in that it  2) Rule according to claim I, characterized in that it  is symmetrical with respect to its median longitudinal plane and  in that its profile corresponds to that of a roof prism  angles at the base &alpha; between 200 and 250, incorporated  of a single mass of transparent material, or made up of  two straight prisms which are almost geometrically  two symmetrical halves of said roof prism.  3) Rule according to claims I and 2 characterized in that  that its oblique faces have a slope break, slope  the lower part of which is inclined at an angle by  relative to the base &alpha; @ of I00 and in that the distance between  the edge of the base prism and the edge of the prism with rupture  slope, measured on the plane containing the base of the prism  (distance d) is at least 10 mm.  4) Rule according to claims T and 2 characterized in that  that its lateral faces have a profile, 6 - and JC 'in arc of cer  -cle, said circle being tangent to both the slope of a  base prism of acute angle cX = 25 and to the right comprising the base of the same prism, said circle therefore having a radius R = h / (2 sin &alpha; / 2), where h is the Ximum height for the material  transparent used.  and whose slopes (I4) are oblique.  -met of said rule, lug whose apex (I3) is rounded  what it has a wedge pin, all along the som  5) Rule according to claims I, 2,3 and 4 characterized in  6) Rule according to claims I, 2,3,4 and 5 caractéri -sée in that it comprises a plate (I2) of white material, of small thickness exceeding masses of transparent material -rente, the upper end8 is cut like the wedge pin.  7) Rule according to claims 1,2,3,4,5 characterized in that its draft can be obtained in a single molding operation.  8) A rule according to claim 7 characterized in that it comprises on its base a central longitudinal groove, colored-white  9) Rule according to the preceding claims taken as a whole, characterized in that its height h is at least 10 mm  IO) Rule according to the preceding claims taken as a whole, characterized in that it is manufactured mainly with polymethyl methacrylate and in that its height h is I2 mm.