CA1079322A - Business forms constructed from coated single sheets selectively folded - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Single sheets coated front and back with chemicals capable of reacting with one another to produce a colored mark are used to construct business forms such as envelopes and manifold sets. The sheet has two fold lines allowing one end panel to be folded over the middle panel and allowing the other end panel, which may be a detachable receipt section to be folded over the first end panel. The first end panel and the middle panel may constitute an envelope. Upon application of pressure to the receipt section or to the top part of a manifold set the contacting coated back of the receipt section is forced into reactive contact with the coated front of the underlying panel to produce the colored mark. Thus, information applied to the outside receipt section can be duplicated on the underlying mating panel.

Description

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This invention relates to a carbonless copyin~ system wherein a single sheet is coated front and back and is selectively folded into a business form such as an envelope or a manifold set, the coatings on the sur-faces of mating sheet portions respectively including compatible initially colorless reactive cornponents capable of reacting to produce a colored mark upon impac~ or the application of pressure.
Known carbonless copying systems involve manifolded sets of carbon-less copying paper which utilize an initially colorless color-forming system and include a plurality of sheets with the upper sheet thereof coated on its back surface (CB) with a solution of a colorless color-former in a suitable solvent, the bottom sheet having its front surface coated (CP) with a solid materia] containing a record-developing material, and the intermediate sheet being coated front and back ~CPB) respectively with the above-mentioned solid record-developing material and with the color precursor. Such back coatings normally comprise pressure rupturable microcapsules containing a fluid color precursor in liquid form which is capable of reacting to thereby form a colored compound with the developing material in the front coating o the next adjacent sheet so that, upon impact by a machine key or application of pressure by a stylus on the upper sheet, the contents of the ruptured capsules in the back coatings spill out and react with the developing material to form a colored mark on the latter which corresponds to the mark impressed by the stylus or machine key. -Illustrative of various types of systems which may be used in the !' production of carbonless transfer papers areJ for example, U. S. Patent Nos.
~ ~ 2,299,694; 2,712,507; 3,016,308; 3,429,827 and 3,720,534. The aforementioned ,~ '507 and '308 paten1:s illustrate the most common variety of carbonless impact transfer paper of the type with which the present invention is concerned wherein microcapsul~s containing a liquid fill comprising a chemically reactive color-forming precursor are coated on the back surface of a sheet~ and a dry coating of a solid co-reactant chemical for the precursor is coated on the ~ ' ~7~32~

front surface of a receiving sheet.
Manifolded sets comprising several sheets of carbonless copying paper of the type aforedescribed constitute a distinct advance over the prior art carbon copying systems utilizing carbon coated tissues or carbon coated surfaces -for the transfer of images between sheets of the set. Among the various obvious advantages of the carbonless copying systems over the carbon transfer system are the avoidance of smudging and the handling of carbon tissues or papers, and the savings in the cost of production and paper with the discontinued need for separate carbon tissue sheets.
Generally, the sup0rimposed coated sheets oE the carbonless copying systems heretofore devised are usable as a manifold set for various business activities except that a plurality of individual sheets must be collated in some manner to produce the manifold set. Also, these superimposed sheets create difficulties in the manufacture of envelopes and manifold sets froM
single sheets selectively folded as in accordance with the invention.
On the other hand, the construction of envelopes and manifold sets from single sheets for a variety of uses is generally known throughout the :! art. In particular, U. S. Patent No. 1,655,912 to McNair et al discloses an envelope foT keeping records constructed from a single sheet having a detach-able record sheet and, with the use of carbon paper, information may be trans-ferred from the record onto the body of the envelope. And, known fanfold -~ sets constructed from single sheets are interleaved with carbon transfer , sheets for imaging onto parts of the set.
It is an object of this invention to provide a business form con-structed of a single carbonless recording sheet coated front and back ~CFB) '~ in accordance with known carbonless copying systems and selectively folded to form an envelope having a detachable receipt section, or to form a manifold '~ set, wherein reactiv0 components of mating CFB surfaces react upon coming in contact with one another. Therefore, upon application of pressure to the ~ 30; receipt section, or to the top part of a manifold set, such contac~ing CB and :.
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CF coatings are forced into reactive contact with one another to thereby produce a colored mark.
It is a further object of this invention A~O provide such an envelope or manifold set construction in a highly efficient and economical mann0r simply by the selective folding of a single carbonless recording sheet.
The envelope is constructed as having an envelope pocket with a detachable receipt section on the envelope flap and foldable together with the flap over the envelope so that images may be transferred, in accordance with one embodiment, from the receipt section directly onto the envelope.
In accordance with another embodiment, such images are transferred from the receipt section onto the envelope through the envelope flap disposed between thc receipt section and the envelope in a folded zigzag fashion. And, the single sheet may be folded as aforedescribed without coated fronts and backs in mating contact except at the portions intended for the transfer of images.
And, the manifold set is constructed similarly to that of the envelope embodiments, for a similar image transfer function, except that, of course, envelope pockets are not formed. .
Thus, according to a first aspect of the present invention, there is provided a business form comprising: a singl0, carbonless recording sheet having coatings on front and back surfaces thereof, said coatings comprising an initially colorless color-forming reactive component, said sheet having a pair of spaced parallel foldlines thereon defining adjacent middle and end panels, one of said end panels being folded over said middle panel along one ~-~; of said foldlines, the other of said end panels overlying said one folded ;~ panel when folded along ~he other of said foldlines, the reactive component of said back coating being capable of reacting to produce a colored mark with :
the reactive component of said front coating upon coming in contact therewith, whereby upon application of pressure to said other end panel, said back :
coating of said oth~r end panel is forced into said reactive contact with said f~ont coating of said one end panel to thereby produce a colored mark.

According to another aspect of the present invention, there is .
; provided a single, carbonless recording sheet selectively folded to form a ~: .. ~ , ~.~ ' ' .

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business form,comprising: coatings on front and back sur~aces of said sheet, said coatings comprising an initially colorless color-~orming reactive com-ponent, spaced parallel foldlines on said sheet defining first, second and third panels, said third panel overlying said second panel with the back surfaces together facing one another, said first panel overlying said third panel with at least a portion of said back surface thereof facing the front surface of said third panel, the reactive component of said back coating being capable of reacting to produce a co:Lored mark Wit}l ~he reactive com-ponent of said front coating upon coming :in contact therewith, whereby upon application of pressure to said first panel, said back surface coating on said first panel is forced into said reactive contact with said front surface coating on said third panel to thereby produce a colored mark.
: The invention will now be described in greater detail with reference .` to the accompanying drawings, in which:
Figure 1 is a cross-sectional view of a single sheet coated front and back used in the formation of an envelope having a detachable receipt section, or in the formation of a manifold set, in accordance with one embodi-ment of the invention;
Figure 2 is a perspective view of the sheet of Figure 1 folded into the envelope; -Figure 3 is a schematic end elevational view, in expanded and enlarged form, of the Figure 2 envelope construction;
Figure 4 is a view similar to Figure 3 of the Figure 1 sheet folded to form a manifold set;
Figure 5 i.s a view similar to Figure 2, at reduced scale, of the . ~ Figure 1 sheet folded to form a manifold set in continuous form having feed `.~ holes along opposite sides;

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~ igure 6 is a schematic end elevational view, in expanded forrn, of the Figure 5 manifold set construction;
Figure 7 is a cross-sectional view of a single flat sheet coated front and back usable in the construckion of an envelope having a de~achable receipt section, or in the construction of a manifold set, in accordance with another embodiment of the invention;
Figure 8 is a perspective view of the Figure 7 sheet folded into the envelope;
Figure 9 is a schematic end elevational view, in expanded and enlarged form, of the sheet folded in accordance with ~igure 8; and Figure 10 is a view similar to Figure 9, at reduced scale, of the Figure 7 sheet folded to ~orm a manifold set.
Turning now to the drawings wherein like reference characters refer to like and corresponding parts throughout the several views, a flat sheet 10 of paper as shown in Figure 1 is conventionally coated as at 11 on its front surface with a solid material containing a record-developing material and this "front coated" sheet is generally referred to as CF paper Sheet 10 is likewise conventionally coated on its back surface as at 12 with an encapsu-lated solution of a colorless color-former in a suitable solven~ and is generally therefore referred to as CB ~"Coated Back") paper. Each of the CB
and CF surfaces include a color-forming reactive material and the reactive material in back coating 12 is capable of reacting with a reactive material in front coating 11, when pressed thereagainst, to produce a colored mark in a manner to be fully described hereinafter. Therefore, when coatings 11 and 12 are forced into reactive contact with one another after the sheet is folded ~ .. ;- , .. ..
as described hereinafter, a colored mark is produced.
Sheet 10 is provided with spaced parallel foldlines 13 and 14 so as to define first, second and third panels 15, 16 and 17, wherein panel 16 com-prises the middle panel and panels 15 and 17 comprise end panels. Sheet 10 is further provided with a line 18 of perforations in panel 15 spaced from ~` -4-and parallel to foldline 13. The section of panel 15 lying between ~oldline 13 and line 18 comprises an envelope flap 19 having a strip 21 of rewettable glue on the back surface thereof. A strip of pressure-sensitive glue may alternatively be provided for the rewettal~le glue strip, and a removable strip of glassine or like material may conventionally cover such pressure-sensitive glue strip. The remaining portion of panel 15 comprises a receipt section 22 detachable along a line 18 o~ perforations.
Flat sheet 10 may be printed on the front surfaces of panel 17 and section 22 respectively with identical blocks 23 and identical blocks 24 ~see Figure 2) having notations thereon such as the date, name and address in blocks 23, and notations such as the type of account of the customer to which his deposit is to be credited to his account with the bank with which he is transacting business. As will be seen hereinafter, the envelope construction generally designated 25 in Figure 2 may be used in an automatic sidewalk banking transaction. Panel 17 of sheet 10 is folded along line 14 so as to tl overlie panel 16 with the coated back sur~aces thereof facing one another as shown in Figure 3. Panels 16 and 17 are pasted together along opposite ends by means of strips 26 of adhesive so as to thereby ~orm an envelope pocket 27 having an open side 28 lying adjacent foldline 13. Sheet 10 is further folded about line 13 so that its panel 15 overlies panel 17 which forms the envelope pocket together with panel 16. As shown in Figure 3, the coated back surface o~ panel 15 is brought into mating contact with the coated front surface o~ panel 17. Also~ the width of overlying panels 16 znd 17 are at least as great as the width of panel 15 so that section 22 is made to directly overlie panel i7.
It should be noted that, in Figure 1, the encapsulated first reactive component of the reaction system is illustrated as a series of small circles containing a plus mark ~3 and the second reactive component of khe reaction system is illustrated as a series of plus marks C~).
Figure 3 illus~rates the manner in which images are transferred onto ' .

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the front surface of panel 17 which is part of the envelope underlying panel 15 as pressure is applied thereto in the direction of arrow 29, when envelope 25 is in use. Coating 12J referenced as CB on the back surface of panel 15, preferably comprises tiny rupturable microscopic capsules having liquid fill therein~ such fill comprising a reactive component thereof. Microcapsules are illustra~ed by small circles so that, when the capsules in coating 12 are ruptured, by the application of pressure by a stylus or machine key to the front surface of panel 15, as shown by arrow 29, mark 31 may i~mediat01y be impressed upon panel 15 of envelope 25 and a corresponding mark 32 is formed on the front surface of panel 17 as the fill from coating 12 of panel 15 spills out of these ruptured capsules to contact and co-react with the reactive component of the reaction system contained in coating 11 generally referenced as CF on the front surface of underlying panel 17. Naturally, since only CB
surface of panels 16 and 17 face one another, no imaging of mark 31 is left i on such surfaces.
Mark 31 typically illustrates the markings made on panel 15 in blocks 23 and 24 as the customer fills in the date, his name and address and the type of account to be credited while corresponding image marks 32 typical-ly illustrate the images appearing on the front surface of panel 17 in the corresponding blocks 23 and 24 thereon. Receipt section 22 may then be detached from the envelope along line 18 of perforations and the deposit may be inserted in the envelope pocket which may be sealed by glue flap 19 and dropped into the receptacle provided for sidewalk banking. The customer then simply inserts his receipt section 22 into an appropriate slot so that his receipt may be validated as in any conventional manner.
Envelope 25 is likewise available for use in the maintaining of records stored and sealed within the envelope pocket and identified on panel ~ ~ 17, whlle being further identified on section 22 which may be filed separately ,: , from the stored document. Also, envelope 25 may be used as a paycheck distri-30; bution instrument wherein the necessary identifring information may be trans-~7~3~

ferred onto the envelope and retained by the bookkeeper as sec~ion 22 is removed, Other obvious uses are likewise available for envelope 25.
A manifold set may alternatively be formed from sheet 10 in lieu of envelope 25 as aforedescribed. Referring to Figure 4, a manifold set 25' is formed by folding end panel 17 along line 1~ to overlie middle panel 16, and by folding end panel 15 along line 13 to overlie panel 17, similarly as in Figure 3. However, glue lines 26 are omitted since no envelope pocket is formed, and glue line 21 is likewise omitted since no envelope flap need be formed. Line 1~ of perforations is consequently removed, and ~oldlines 13 and 14 are devi.sed as lines of perforations. As in the Figure 3 embodiment, the CB surface of panel 15 faces the CF surface of panel 17 so that, upon the application of pressure along arrow 29, a mark 31 may immediately be impressed upon panel 15, forming an upper panel or part one of the manifold set, wi*h a correspond m g mark 32 being formed on panel 17 constituting the middle panel or part two of manifold set 25'. ~ark 32 is formed in the same manner as that described for Figure 3. Also, it should be noted that set 25' may be constructed as a unit set, as contrasted by a set formed from a con-tinuous assembly and burst along transverse lines, so that set 25' may be oriented 90 from that of Figure 2 when in use. Blocks 23 and 24 imprinted on panels 15 and 17 will therefore extend perpendicularly to such blocks as seen in Figure 2.
Since the CB surfaces of panels 16 and 17 face one another, no image of mark 31 is transferred to panel l6 which is accordingly available for use as~a different type copy of the three-part manifold set. Panels 15 -~
and 17 may be detached from the set along their respective lines 13 and 1 of perforations.
A manifold set 25" may likewise be forlned from sheet 10 folded similarly as in Pigure ~. Referring to Figure 5, it can be seen that a plurality of sets 25" may be formed from a continuous sheet 10 and separated ~30 from one another as by bursting along transverse lines 33 of weakening which ~7~3Z~

are superimyosed between overlapping panels 15, 16 and 17. Each set 25" is identical to set 25' of Figure ~ except that feed hole strips 34 are provided in panels 15 to 17, as shown in Figures 5 and 6, to facilitate feeding the continuous sheet through high speed data processing equipment. Such strips may be detached along longitudinal lines 35 of weakening in the conventional manner. Blocks 23 containing the desired data may therefore be imprinted on connected panels 15 with the images thereof transferred onto connected panels 17 while the continuous sheet moves through such equipment. Image transfer is effected similarly as described with reference to Figures 3 and 4, and is shown diagrammatically in Figure 6. Upon removal of the feed strips, the panels of this three-part set are detached with panel 16 being usable as an advertising part, for example.
In another embodiment of the invention, flat sheet 36 is shown in Figure 7 having coatings 37 and 38 on its front and back surfaces, respective-ly, these coatings being designated CF and CB in Figures 7 ~o 9 and being the same as respective coatings 11 and 12 described with reference to the first embodiment. Sheet 36 is provided with spaced and parallel foldines 39 and 41 thereby defining first, second and third panels 42, 43 and 44 wherein panel 43 is a middle panel and panels 42 and 44 are end panels. A line 45 of perforations is provided in panel 42 spaced from and parallel to foldline 39 i thereby defining an envelope flap 46 between lines 39 and 45 and a receipt ,~ section 47 detachable from the flap along line 45 of perforations. As in the first embodiment, the flap is provlded on its back surface with a strip 48 of adhesive whlch may be rewettable glue or pressure-sensitive adhesive covered with a removable glassine cover strip or the like.
In *he formation of the envelope construction shown in Figures 8 and 9, panel 44 of ~heet 37 is folded along line 41 to overlie panel 43 with the coated back surfaces thereof fac m g one another as shown in Figures 8 and 9. Opposite ends of these panels are secured together along lines 49 of adhesive so as to define an envelope pocket 51 having an opening 52 lying ,, :

~0 adjacent foldline 39.
The width of flap 46 is substantially the same as the width of the envelope pocket so that, when folded along line 39 to overlie the envelope pocket, flap 46 is in direct overall contact therewith. And, section 47, being of a width substantially the same as the width of flap 46~ is in direct overall contact therewith when folded along line 45 to overlie the flap.
Since the respective coated back and coated front surfaces of panels 46 and 44 face one another, images may be transferred from section 47 onto panel 44 through flap 46. The coating 37 on the front surface of panel 44 has a react-ive material capable of reacting with a reactive material in back coating 38 provided on flap 46 so that, when these CB and CF coatings are pressed against one another, a colored mark is produced similarly as described for the Figure 3 embodiment. Hence, when the microcapsules in coating 38 on the back surface of flap 46 are ruptured as by the pressure by a stylus or machine key to the upper surface of section 47, as indicated by arrow 53 in Figure 9, a mark 54 may immediately be impressed on section 47 with a corresponding mark 55 formed , on the upper surface of panel 44 as the fill from coating 38 of section 47 ' spills out these ruptured capsules to contact and co-react with the second reactive component of the system. ' It should be noted ~hat blocks 56 and 57 may be printed on both the CB surface of section 47 and on the CP surface of panel 44 as shown in Figure 8 so that, upon zigzag folding of the envelope generally designated 58 in Fig~lres 8 and 9, the images of markings 54 applied in ~locks 56 and 57 on section 47 are t mnsferred onto corresponding bloGks 56 and 57 of''panel 44.
Blocks 56 and 57 may respectively provide'for the name and address of the customer to be filled in and the type of account of the customer to be credited with the bcmk if~ for example, envelope 58 is to be used as a banking-by-mail enve]ope. Instructional indicia may likewise be printed on the CB
surface of section 47 pertaining to the manner in which blocks 56 and 57 there-on are to be filled~in, and instructing the customer to separate receipt sect-: .
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ion 47 along line 45 of perforations after the necessary information is filled in. Such instructions will likewise direct the cus~omer to insert the deposit within envelope pocket 51 and thereafter seal the envelope using flap ~6. Of course, envelope 58 is available for other uses such as utility bill payments or bank loan payments wherein a receipt to be retained by the custo-mer becomes desirable. Such receipt is likewise duplicated on panel 44 form-ing the envelope pocket so as to provide a duplicate record for the utility company or the bank as well.
Sheet 36 may likewise be folded similarly as in ~igure 9 to form a four-part manifold set 58' shown in Pigure 10. Glue lines 49 and 48 are therefore omitted, and lines 39 and 41 are devised to function as tear lines similarly as line 45. Images 55 of marks 54 applied to section ~7, forming part one of the set, are transferred to panel 44, forming part three of the set, similarly as in Figure 9. Sections 46, 47 and panels ~3, 44 may then be I separated from the set along lines 45, 39 and 41. And, it should be noted j . .that manifold set 58' of Figure 10 may be a unit set or may be formed from a continuous sheet having feed hole strips and transverse lines thereon as in Il Figure 5.
! As described in Canadian Patent No, 1,055~987, issued June 5, 1979 and commonly owned herewith, the precursors useful in connection with carbon-less copying systems are mentioned in United States Patent No. 3,455,721.
These materials are capable of reacting with a CF coating containing an acidic .
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: material such as the acid-leached bentonite-type clay disclosed in commonly l~ owned Canadian Patent No. 972,561~ issued August 12, 1975, or the acid-:i~ reactant organic polymeric material disclosed in the aforementioned t721 ,, .patent. There are cL large number of patents which relate to initially ~ .:

¦~ ~ colorIess color precursors use~ul in connection with carbonless copying ~ systems, although the present invention does not rely on the precise identity .~ or nature of the reactants utilized except that at least one system of co-reactants is required for each of the two disclosed embodiments.

: : The react.ion system usable or the present invention may be the same as either the first or the second initially colorless reaction sys~em ~ ~ - 1 0-,: ~
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disclosed in ahove mentioned Canadian Patent No. 1,055,987. As set forth therein, any of the materials may be utili~ed which are ~isclosed in the aforementioned '721 patent and which are capable of undergoing an acid-base type reaction with an acidic material. Also operable in connection with the system are the spirodipyran compounds disclosed in United States Patent No.
3,293,060. Particularly useful color precursors are disclosed in United States Patent Nos. 3,193,~0~; 3,278,327 and 3,377,185. These color precursors as well as those disclosed in the aforemenl:ioned '060 patent and in the '721 patent are initially colorless and àre capable of becoming highly colored when brought into contact with an acidic material such as acid activated bentonite clay or an acid-reacting polymeric material, or the like. Similarly as in the aforementioned '623 commonly owned patent application, there are any number of similar color precursors capable of undergoing a reaction with an acid coating to produce a color which are usable herewith.
In each of these color-forming systems, it is conventional for the -, color precursors to be contained in pressure rupturable microcapsules which are coated on the backs of the sheets, although the exact nature of the capsule itself is not critical so long as the same is capable of containing the color precursor with the capsules capable of being ruptured upon impact in accordance with the conventional carbonless copying procedures. Also, ~` the acidlc coatings are normally coated on the fronts of the sheets with the color precursor material in a solvent therefore being transferred from an adjacent back coating to the acidic layer front coating upon rupture of the adjacent capsules whlch contain the color precursor material.
From the foregoing, it can be seen that business forms are con- --structed from single sheets coated front and back with co-reactants of a carbonless copying reaction system and, by selective folding, CB and CF sur- ~ -:, , ~ faces are mated to p~oduce a colored mark upon application of pressure forcing ~ .

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~0 ~ 2 a back coating into a reactive contact with the front coating. Otherwise, the respective CB and CF coatings of the folded parts face one another so that colored marks are incapable of being produced upon application of pressure on those surfaces not intended for image transfer. And, since the envelopes and the manifold se~s are constructed of single sheets, they are economical to produce, easy ~o handle and efficient in their use by the customer.
Obviously, many modifications and variations o~ the present invent-ion are made possible in the light of the above teachings. It is therefore to be understood that within the scope o~ the appended claims, the invention may be practiced otherwise than as specifically described.

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Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A business form comprising: a single, carbonless recording sheet having coatings on front and back surfaces thereof, said coatings comprising an initially colorless color-forming reactive component, said sheet having a pair of spaced parallel foldlines thereon defining adjacent middle and end panels, one of said end panels being folded over said middle panel along one of said foldlines, the other of said end panels overlying said one folded panel when folded along the other of said foldlines, the reactive component of said back coating being capable of reacting to produce a colored mark with the reactive component of said front coating upon coming in contact therewith, whereby upon application of pressure to said other end panel, said back coating of said other end panel is forced into said reactive contact with said front coating of said one end panel to thereby produce a colored mark.

2. The business form according to claim 1, wherein said back coating comprises a plurality of pressure rupturable micro-capsules containing a color-forming component thereof, said micro-capsules being rupturable upon applicat-ion of pressure to said other end panel.

3. The business form according to claim 1, wherein said foldlines are defined by lines of perforations permitting said end panels to be detached from said middle panel.

4. The business form according to claim 1, wherein said one end panel overlying said middle panel is secured thereto along opposite ends thereof so as to define an envelope pocket having an open side lying adjacent said other foldline.

5. The business form according to claim 4, wherein said other end panel has a line of perforations thereon defining a detachable receipt section and an envelope closing flap having adhesive thereon for closing said envelope.

6. The business form according to claim 4, wherein said back coating comprises a plurality of pressure rupturable micro-capsules containing a color-forming component thereof, said micro-capsules being rupturable upon application of pressure to said other end panel.

7. The business form according to claim 5, wherein the width of said other end panel is less than the width of said underlying envelope, whereby upon application of pressure to said receipt section, said back coating thereof is forced into said reactive contact with said front coating of said one end panel to thereby produce the colored mark.

8. The business form according to claim 1, wherein said other end panel has a line of perforations thereon parallel to said foldlines and dividing said other end panel into a first section overlying said one end panel and a second section folded along said line of perforations to overlie said first section, whereby upon application of pressure to said second section, said back coating of said first section is forced into said reactive contact with said front coating of said one end panel to thereby produce the colored mark.

9. The envelope according to claim 5, wherein the width of said flap is substantially the same as the width of said underlying envelope, and said receipt section is capable of being folded along said line of perforations to overlie said flap, whereby upon application of pressure to said receipt sect-ion, said back coating of said flap is forced into said reactive contact with said front coating of said one end panel to thereby produce the colored mark.

10. A single, carbonless recording sheet selectively folded to form a business form, comprising: coatings on front and back surfaces of said sheet, said coatings comprising an initially colorless color-forming reactive com-ponent, spaced parallel foldlines on said sheet defining first, second and third panels, said third panel overlying said second panel with the back sur-faces together facing one another, said first panel overlying said third panel with at least a portion of said back surface thereof facing the front surface of said third panel, the reactive component of said back coating being capable of reacting to produce a colored mark with the reactive component of said front coating upon coming in contact therewith, whereby upon application of pressure to said first panel, said back surface coating on said first panel is forced into said reactive contact with said front surface coating on said third panel to thereby produce a colored mark.

11. The sheet according to claim 10, wherein said foldlines are defined by lines of perforations permitting said first and third panels to be detached from said second panel.

12. The sheet according to claim 10, wherein said third panel is secured to said second panel along opposite ends so as to form an envelope pocket open along a side lying adjacent one of said foldlines.

13. The sheet according to claim 12, wherein said first panel has a line of perforations thereon defining an envelope closing flap extending between said one foldline and said line of perforations with the remainder of said first panel defining a receipt section, said flap having adhesive thereon for sealing said open side of said envelope.

14. The sheet according to claim 10, wherein said back coating com-prises a plurality of pressure rupturable microcapsules containing a color-forming reactant thereof, said microcapsules being rupturable upon application of pressure to said first panel.

15. The sheet according to claim 13, wherein said back coating com-prises a plurality of pressure rupturable microcapsules containing a color-forming reactant thereof said microcapsules being rupturable upon application of pressure to said first panel.

16. The sheet according to claim 13, wherein said line of perforations is disposed closely adjacent said one foldline, and the width of said second panel being at least as great as the width of said first panel, the entire back surface of said first panel thereby facing the front surface of said third panel, whereby upon application of pressure to said receipt section, the back coating thereof is forced into said reactive contact with the front coating of said third panel to thereby produce the colored mark.

17. The sheet according to claim 13, wherein said line of perforations lies closely adjacent the other of said foldlines during an overlying relat-ionship of said first and third panels, the back surface of said flap thereby facing the front surface of said third panel, and said receipt section over-lying said flap, whereby upon application of pressure to said receipt section, the back coating of said flap is forced into said reactive contact with the front coating of said third panel to thereby produce the colored mark.