scanning blank receipts?

No, the faded receipt is not directly scanned with a typical office scanner, scanners rely on at least enough contrast to register an image. The only way I can see to do it is to have facilities at HQ to either heat the receipt or expose it to a chemical treatment to restore the contrast, or use alternate wavelength (UV? IR?) in a special scanner.

"but to keep it simple I'll just start with one question here." Say What???

Explain what a "disappearing sales receipt" is. Never received one nor saw one, maybe it merely disappeard accidently and a normal receipt is/was hand to me as I picked up my merchandise and walked out the door.

"How is it possible for Home Depot (or any other It) to do it, whether by scanning or otherwise?"

All of the sales transactions are in the computer system and while the store is not able to reconstruct one due to possible misuse for fraudulent purposes the central computer operations staff can.

Are you referring to thermal paper???

If as you say "I did my research" you would have known to use the proper terminology!

That's right Stan. He is referring to thermal paper which as you know fades fairly rapidly.

Now I'm curious as to the chemistry so I can determine if the information is recoverable.

j.

Jack Jersawitz The chemistry/physics of thermal paper would be interesting information. If he is intent on preserving the original receipt, then it must be protected from heat and light. For a valuable purchase and proof of date etc. I would try to make a photo copy ASAP an attach the original to the copy. For ordinary purchase why bother.

OTOH the Dept. of Agriculture wants to track every farm animal, elks, deer, and..... with RFID's. Why not having to keep every sales slip of ever purchase forever?

Even buried in your wallet those images fade.

Electrostatic copying of image before it fades is a good idea and yields a reasonably long life document, at least the life of the paper, cause the image is composed of fused on plastic.

I can explain electrostatic copying, the imaging materials. I can explain the lithographic printing process, either archaic stone images, or modern metal plates on offset presses, the fountain chemistry, etc.

But thermal imaging????

j.

Jack Jersawitz IIRC Thermal coping machines replaced the messy dye-gelatin process many years ago. The thermal copy was made by a heated stylus or maybe an optical image of one.

From your last post it appears to be a chemical/thermo photo reaction which becomes unstable over time.

Stan,

Not talking about the dye-gelatin hectograph process. Talking about photo-offset lithography, metal photo imaged plates on modern machines or the original art form, greasy crayon images on porous stone, i.e., stone lithography.

The images we were taking about, register receipts, do become unstable over time...they vanish.

My last post, apparently the chemistry of the register imaging process, is incomprehensible to me.

j.

Then again I looked and it is beyond me. I used to know the chemistry of a good many imaging processes, but this is beyond me.

Dow e have a chemist on board to reduce the gibberish below into understandable concepts?

j.

ONLINE ISSN: 1349-6336 PRINT ISSN: 0914-9244

Journal of Photopolymer Science and Technology Vol.12 , No.2(1999)pp.325-330

[ Full-text PDF (293K) ] [ References ]

Studies about Thermal Decarboxylation of Hydroxyl Benzoic Acids used in Thermal Imaging Yingquan Zou 1), Xiao Tong1), Weijian Zhao1), Peng Wu1) and Shangxian Yu1) 1) Department of Chemistry, Beijing Normal University [Received: 1999/03/26] [Released: 2006/08/04] Abstract: Six isomers of dihydroxyl benzoic acid and three isomers of trihydroxyl benzoic acid were analysed systematically with thermogravimetric analysis. They, the starting temperatures (T S), the peak temperatures (TP) and the end temperatures (Te) in the decarboxylation reactions, were worked out based on the integral curves (TG) and the differential curves (DTG) in thermogravimetric analysis of these compounds. The carbon atoms of benzene rings connected with carboxyl groups of these compounds are numbered as C1, and the carbon atoms of carboxyl groups are numbered as C7. The chemical shift values of C1 (δ1) and C7 (δ7) are from the NMR spectra of these compounds, and it is found that there is a linear relation between TP and δ1 or (δ7-δ1). The net charge values of C1 (q1) and C7 (q7) are from the calculations of quantum chemistry. After compared δ1 and(δ7-δ1) with q1 and(q7-q1) respectively, it is also found that there are linear relations between them. These prove that there is a close relation among δi, qi and the reactivity of i-position on the benzene ring of a phenolic compound. Keywords: Hydroxylbenzoic acid, Decarboxylation, Thermal imaging

or are we really looking for proprietary information? Could there really be something to his "disappearing receipts" notion that not everyone is onto yet?

What that means is: it appears it might be possible, based on the abstract you presented, for the life-expectancy of a printed paper to be adjusted at a predetermined length of time. While that is not directly what was asked it would certainly be closely related. Wouldn't it?

http://www.journalarchive.jst.go.jp/english/jnlreference_en.php?cdjournal=photopolymer1988&cdvol=12&noissue=2&startpage=325

Hello Jack Jersawits,

have just read the bit you copies about thermal printing etc. Come on Jack, I would have thought that was obvious!.....LOL Interesting subject though isn't it?

I will now take a look at the link you enclosed. Thanks. Been a long time since I was at school, and learned almost nothing! Learned what I know now after leaving. Wish I was as brainy as you though.

jfmfit.

Hello Jack Jersawitz,

Not sure if I have it or not, but the till receipt paper is coated or made with the Decarboxylation of Benzoic Acids, which is essentially a salt solution?

jfmfit

I took a look at this - it is some basic chemistry about thermal imaging materials, apparently. My best guess is that it is cheaper and easier to print with than traditional inks. It looks as if at least part of the reason the image fades is due to the acidic nature of most common papers. The material seems to be stable under neutral to basic pH conditions. I don't think this is actually intended as a security feature, I think some creative marketing types took the already-present fading nature into consideration and thought "hey, we can make this look like a helpful feature!" whether it is for everyone or not.

Hello CowAnon,

I had to keep receipts for petrol, and items bought to do my job on-site, I was a builder. I lost at least £800.00, which I could not prove I had bought goods to match and so, I started asking for written receipts. Very frustrating. Perhaps there should be a warning on each receipt to say that it will fade? By the way, my receipts were kept in a metal file draw so were not open to the light and certainly did not get hot as the site office was a caravan with no heater!

I had this problem with my petrol and other receipts. I live in the UK so, it must be pretty universal, as that was 20 years ago. I now find local shop receipts fade and cannot be read after just a couple of months.

I cannot help you but will be checking out your posts and replies from other and, have a look at the physics of the paper and print process to see why this is. It could be as simple as using a UV light which you can use to check for 'dud' bank notes. Just a few pounds, or in your case dollars.

You have got me thinking now. By mentioning an apparently inconsequential thing, but, it affects everyone!

jfmfit

Photo copy (scan) all important receipts and print a copy off on a printer that does not suffer in this way (almost any inkjet or laser will do).

Keep an electronic copy as well in a special folder on your PC....back up your PC each week at least once if not more often!!

Scanners are cheap as are PCs and printers.....losing one $800 receipt (as someone mentioned) is tantamount to paying for all three items and still getting change back!!!! and if its a business, you can offset all three items against taxes!!!

Hello Andy Germany,

the someone who lost the £800, thats 8 hundred UK pounds, which then was equal to over $1200. That was almost a years worth of receipts, is me. It was like a huge pay-cut. But, there was no computers then and remembering which shops and petrol stations I went to, in a 64 Km radius was impossible. There was photo-copiers but, people like me working out the back of a van at the time, well, it was just not part of my vocabulary.

jfmfit

....I bet you have learnt a lot since then......but corner photo copy shops have been around a lllloooonnnnggg time.....

Remember that these printed till receipts have been around a shorter time than PCs.....!

My answer may have been out of the time frame (but you never set one!) with regard to a PC etc., but today, you have no excuse not to do it right!!

Hello Andy Germany,

I have been thinking, (I do it now and then) it was only about 14 years when I had the till receipts that faded, and I lost all the money.I cannot work now due to Epilepsy, so it is not as critical to record as it once was.

Mind you, if they can design what I think is an over complicated salt solution for the paper of the receipts, and can as described, alter or vary the time the 'print' stays visible, why design something that fades in less time than we, in the UK at least, have to keep all financial paperwork for six years. I have noticed just in the last say, four years, the fading is taking a shorter time. I never thought of photocopying them in the past, but I will now. Take care.

jfmfit

You too.

Make your own copy with laser/inkjet copier, when you go to your office or Home.

Or use a digital camera or cell phone camera, most people have one or the other now.

"I've been under the impression, perhaps mistakenly(?), that this would be done by scanning of the (apparent) blank."

Do they really scan the receipt to recover the information or just use it as validation of your request before reprinting the receipt from a till record stored electronically?