US3979550A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pre-printed latent image spirit duplicating masters
Assignee: Mazer Corp
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Filing: 1975-12-10
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Granted: 1976-09-07
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Expires: 1995-12-10
Abstract
Abstract A pre-printed spirit duplicating master containing visible imaged material and latent imaged material for use in preparing copies for self-instructional examination or work assignments. The latent images on the copy sheet are capable of being revealed with a pen containing a chemical developer and this can be done by the student in self-examination. The use of the pre-printed masters frees the teacher from the chore of preparing exams, or work assignments, making the masters, and from grading the papers.
Inventors
- 👤 Irving Panken
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:00
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/025; B41M5/04; B41M3/00; B41M3/001; Y; Y10; Y10S; Y10S101/00; Y10S101/29
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
179 words
A pre-printed spirit duplicating master comprising a sheet having reverse printed on the backside thereof by means of a printing technique selected from the group consisting of offset, rotogravure, letterpress, stencilling, or aniline printing, a visible image spirit duplicating ink in one area and a latent image spirit duplicating ink in another area, both said visible and latent inks, when contacted with an alcohol or spirit wetted copy paper, being capable of transfer to said copy paper to impart corresponding visible and latent images thereon, said corresponding latent image being capable of development into a second visible image by application of a color developer thereto, said latent image spirit duplicating ink containing a color former selected from the group consisting of dithiooxamide and derivatives thereof and a carrier vehicle therefor, said latent image ink being resistant to changes in temperature and humidity, capable of producing at least 100 acceptable copies and capable of making copies with little or no loss of intensity in the developed image after being stored for a period of at least up to 1 year.
Claim 2
Dependent Claim
179 words
A pre-printed spirit duplicating master comprising a sheet having reverse printed on the backside thereof by means of a printing technique selected from the group consisting of offset, rotogravure, letterpress, stencilling, or aniline printing, a visible image spirit duplicating ink in one area and a latent image spirit duplicating ink in another area, both said visible and latent inks, when contacted with an alcohol or spirit wetted copy paper, being capable of transfer to said copy paper to impart corresponding visible and latent images thereon, said corresponding latent image being capable of development into a second visible image by application of a color developer thereto, said latent image spirit duplicating ink containing a color former selected from the group consisting of dithiooxamide and derivatives thereof and a carrier vehicle therefor, said latent image ink being resistant to changes in temperature and humidity, capable of producing at least 100 acceptable copies and capable of making copies with little or no loss of intensity in the developed image after being stored for a period of at least up to 1 year.
Claim 3
Dependent Claim
30 words
The preprinted master of claim 1 wherein said latent image ink color former comprises a dithiooxamide derivative selected from the group consisting of N, N'bis-2-hydroxyethyl dithiooxamide, N,N'didodecyl dithiooxamide, and N,N'dimethyldithiooxamide.
Claim 4
Dependent Claim
17 words
The preprinted master of claim 2 wherein said visible spirit duplicating ink contains a crystal violet dye.
Claim 5
Dependent Claim
36 words
The preprinted master of claim 3 wherein said latent image ink is a hot melt ink, said vehicle is a stearate resin and said visible image ink is a hot melt ink containing a carnauba wax.
Claim 6
Dependent Claim
23 words
The preprinted master of claim 2 wherein said latent image ink is a hot melt ink and said vehicle is a stearate resin.
Claim 7
Dependent Claim
23 words
The preprinted master of claim 1 wherein said latent image ink is a hot melt ink and said vehicle is a stearate resin.
Claim 8
Dependent Claim
24 words
The preprinted master of claim 6 wherein said stearate is selected from the group consisting of propylene glycol monohydroxy stearate and glycol mono-hydroxy stearate.
Claim 9
Dependent Claim
27 words
The preprinted spirit duplicating master of claim 1 wherein said sheet has printed on the first side thereof information which is reverse printed on the back side.
Claim 10
Dependent Claim
83 words
A pre-printed spirit duplicating master having an image printed on the front side and reverse printed by means of a printing technique selected from the group consisting of offset, rotogravure, letterpress, stencilling or aniline printing on the back side a visible image spirit duplicating ink and in another area latent image spirit duplicating ink comprising by weight 20-27% stearate resin, 8-17% fatty acid, 8-10% mineral oil, 2-4% petroleum jelly, 0-1% wetting agent, 0-1% ultraviolet absorber, and 44-54% of a dithiooxamide derivative color former.
Claim 11
Dependent Claim
83 words
A pre-printed spirit duplicating master having an image printed on the front side and reverse printed by means of a printing technique selected from the group consisting of offset, rotogravure, letterpress, stencilling or aniline printing on the back side a visible image spirit duplicating ink and in another area latent image spirit duplicating ink comprising by weight 20-27% stearate resin, 8-17% fatty acid, 8-10% mineral oil, 2-4% petroleum jelly, 0-1% wetting agent, 0-1% ultraviolet absorber, and 44-54% of a dithiooxamide derivative color former.
Claim 12
Dependent Claim
27 words
A pre-printed spirit duplicating master as set forth in claim 9 wherein said stearate is a polypropylene mono-hydroxystearate blended with up to 25% of a cellulose ester.
Claim 13
Dependent Claim
32 words
A pre-printed spirit duplicating master as set forth in claim 9 further including a protective sheet adhesively attached to said master to protect said spirit duplicating inks from smearing prior to use.
Claim 14
Dependent Claim
167 words
In a spirit duplicating process wherein multiple copies are prepared by contacting a master with copy paper wetted lightly with an alcohol or spirit capable of dissolving some of the ink of said master whereby ink is transferred from said master to the copy paper, the improvement comprising: contacting said wetted copy paper with a preprinted master having reverse printed on the side thereof which contacts the copy paper, a visible image spirit duplicating ink in one area and a latent image spirit duplicating ink in another area, said latent image ink containing a color former selected from the group consisting of dithiooxamide and derivatives thereof and a carrier vehicle therefor, transferring said inks to said copy paper and forming on said copy paper a positive visible image and a positive latent image, said positive latent image containing said color former selected from the group consisting of dithiooxamide and derivatives thereof and being capable of development into a visible image by application of a color developer thereto.
Claim 15
Dependent Claim
167 words
In a spirit duplicating process wherein multiple copies are prepared by contacting a master with copy paper wetted lightly with an alcohol or spirit capable of dissolving some of the ink of said master whereby ink is transferred from said master to the copy paper, the improvement comprising: contacting said wetted copy paper with a preprinted master having reverse printed on the side thereof which contacts the copy paper, a visible image spirit duplicating ink in one area and a latent image spirit duplicating ink in another area, said latent image ink containing a color former selected from the group consisting of dithiooxamide and derivatives thereof and a carrier vehicle therefor, transferring said inks to said copy paper and forming on said copy paper a positive visible image and a positive latent image, said positive latent image containing said color former selected from the group consisting of dithiooxamide and derivatives thereof and being capable of development into a visible image by application of a color developer thereto.
Claim 16
Dependent Claim
30 words
The process of claim 12 wherein said latent image ink color former contains a dithiooxamide derivative selected from the group consisting of N, N'bis-2-hydroxyethyl dithiooxamide, N,N'didodecyl dithiooxamide, and N,N'dimethyl dithiooxamide.
Claim 17
Dependent Claim
16 words
The process of claim 13 wherein said visible spirit duplicating ink contains a crystal violet dye.
Claim 18
Dependent Claim
35 words
The process of claim 14 wherein said latent image ink is a hot melt ink, said vehicle is a stearate resin, and said visible image ink is a hot melt ink containing a carnauba wax.
Claim 19
Dependent Claim
21 words
The process of claim 13 wherein said latent image ink is a hot melt ink and said vehicle comprises a stearate.
Claim 20
Dependent Claim
22 words
The process of claim 12 wherein said latent image ink is a hot melt ink and said vehicle is a stearate resin.
Claim 21
Dependent Claim
23 words
The process of claim 17 wherein said stearate is selected from the group consisting of propylene glycol monohydroxy stearate and glycol mono-hydroxy stearate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |