Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-11-12
2001-10-09
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031170, C106S031320, C106S031340, C106S031640, C106S031660
Reexamination Certificate
active
06299674
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a fingerprint detecting agent and a method for detecting fingerprints using the agent. More particularly, the present invention relates to a fingerprint detecting agent and a fingerprint detecting method by which latent fingerprints can be detected only by making the agent contact to the latent fingerprints. Particularly, according to the invention, even if latent fingerprints to be detected are in a wet condition, it is possible to detect them easily and speedily.
BACKGROUND ART
Fingerprints are an important proof aiding and arresting accused offenders and therefore to detecting fingerprints is a very important factor in criminal investigations. Conventional fingerprint detection is carried out in such a manner that aluminum powder is put on the surface of an object to be investigated where fingerprints adhere or on a surface of an object which is considered to have fingerprints adhered to there. The object is swept with a brush to adhere the powder on the latent fingerprints to actualize them; then the actualized fingerprint is printed on a gelatin paper (hereinafter called the “dry powder method”).
However, in the conventional dry powder method, if the object to be investigated or the latent fingerprint adhered to on the object is wet, it is impossible to adhere the aluminum powder on to the latent fingerprint to actualize it; in such a case, it is necessary to wait until the object to be investigated, such as a wet window, a wet door, a wet of vehicle body or any other article left on a criminal site, gets dry or to make them dry by using, for example, a dryer. Such processes are complicated, and further the latent fingerprints sometimes disappear in such wet conditions. In this manner, according to the conventional dry powder method, it is very difficult to detect fingerprints, particularly, outside under wet rainy weather.
On the other hand, the conventional dry powder method requires a skill to actualize the latent fingerprint by swiping. Therefore, a non-skilled person sometimes causes damage to the ridged line of the fingerprint to be detected in spite of the wet or dry conditions.
Further, in case the surface of the object to be investigated is large or a large number of the articles are left at a criminal site, the wiping work is so hard because the operator has to wipe them with a brush continuously and very carefully at every small region, for example, 10×10 cm square or on every article left at the site.
DISCLOSURE OF INVENTION
The present invention has for its object to provide a fingerprint detecting agent and a method for detecting fingerprints using the agent by which latent fingerprints can easily be detected by only spraying the agent, particularly, even if the latent fingerprints are in a wet condition, it is possible to detect them speedily and certainly.
In order to carry out the above object, the present inventors created a way to cover the latent fingerprints with the agent and simultaneously to remove the water which adheres on the latent fingerprints and then actualize the fingerprint with the cover by spraying a powder. The present inventors found out that if an agent containing a mixture of a special kind of fixer and developer is applied to actualize the latent fingerprint, the above object can be achieved.
That is to say, the fingerprint detecting agent according to the present invention, can be used to detect latent fingerprints in a wet condition; contains a fixer, a diluent, and a developer; said fixer contains at least one selected from a group consisting of a silicone series compound, a fluorine series compound, hydrocarbon series compound, animal and/or vegetable oil, a higher fatty acid and a higher alcohol; said diluent contains a polar solvent; and said developer contains achromatic or chromatic powder.
Further, the method for detecting fingerprints according to the present invention using said fingerprint detecting agent has a feature that the fingerprint detecting agent is made to contact to a latent fingerprint to be detected.
The detail is still not apparent as to why latent fingerprints, particularly, latent fingerprints in a wet condition can be detected so quickly, but it may be guessed as in the following.
That is to say, when the diluent is mixed with the oil component contained in the fingerprint to be detected, the latent fingerprint is made to contact the developer to cause an absorption reaction so that the fingerprint is actualized; at the same time, the whole surface of the object to be investigated where the developer adheres is coated with the fixer. Then, the developer adhering to the other portion of the fingerprint is removed in a washing process with a water because the adhering force between the developer and the other portion is weak, so that only the developer adsorbed by the fingerprint portion remains.
The fingerprint detecting agent according to the present invention will be explained in detail.
As stated above, the fingerprint detecting agent according to the invention contains a fixer, a diluent and a developer.
Silicone series compound, fluoride series compound, hydrocarbon series compound, animal oil, vegetable oil, higher fatty acid, and higher alcohol and an arbitrary mixture of these materials can be cited as the fixer.
Further, denaturing silicone and/or dimethyl silicone can be cited as the silicone series compound; an amino denaturing silicone, alkyl denaturing silicone, carboxy denaturing silicone, polyalkylen denaturing silicone or epoxy denaturing silicone and an arbitrary mixture of these materials can be stated as the denaturing silicone.
Furthermore, it is preferred to use a silicone series compound having a boiling point more than 250° C., because the compound having a boiling point less than 250° C. sometimes volatizes.
When the dimethyl silicone is used, it is preferred to use a dimethyl silicone having a viscosity of about 2~1000 cSt. If the viscosity of the dimethyl silicone is smaller than 2 cts, the silicone is volatized so that the fixing force thereof is significantly decreased. On the other hand, when the viscosity exceeds over 1000 cSt, the stabilization for storing the fingerprint detecting agent decreases.
A fluoride oil, and fluoride resin dispersion can be cited as the fluoride compound, but a fluoride oil is preferred. Such a fluoride oil is represented by the following chemical formulae (1) and (2).
Next, the diluent should contain a polar solvent, but it is not limited if the fixer and the solute can be dispersed uniformly by the diluent.
For the polar solvent, water, any kind of alcohol or a mixture thereof can be cited as an example; a lower alcohol having a carbon number of 1 to 3 can be stated as an example of the alcohol, particularly, isopropylalcohol can be preferably used.
The other usable solvents are: alcohol having one valency, alcohol having a plurality of valencies, glycol ether, acetate, alkanolamine, ketone group and ether group. Further, it may be possible to add a stabilizer assistant into the agent in order to improve the stabilization of the solvent in the liquid phase of the agent. As such a stabilizer assistant, an organic acid, such as carboxylic acid and sulfonic acid; a non organic acid, such as hydrochloric acid, sulfuric acid and nitric acid; a non-organic alkali, such as ammonia and sodium hydroxide; an organic amine, such as morpholine; a surface active agent, etc. can be stated.
In case that the mixture of amino denaturing silicone and dimethyl silicone is used as the fixer, it is preferred to use a mixed liquid of water and isopropyl alcohol as a diluent. Further, an organic acid, such as carboxylic acid, sulfonic acid and sulfinic acid; a non-organic acid, such as hydrochloric acid, sulfuric acid, and nitric acid; and surface active agent, etc. can be preferably used as a stabilization assistant at this stage. Furthermore, a preservative, such as parabens, etc. may be added.
As non-colored or colored powder contained in the developer, several kinds of non-organic or organic powder can be use
Fukuchi Takashi
Ikeda Atsushi
Ishizawa Fujio
Miyagi Akira
Ochiai Nobuyasu
Faison Veronica F.
Klemanski Helene
Taiho Industries Co. Ltd.
Tolpin Thomas W.
Welsh & Katz Ltd.
LandOfFree
Fingerprint developing agent and method for developing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fingerprint developing agent and method for developing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fingerprint developing agent and method for developing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2603164