Why do black marks appear when you scratch the ticket with your fingernails?

The main reason why black marks appear when the ticket is scratched with a fingernail is that the printer paper is affected.

The paper is called thermal printer paper, which is composed of carbon.

And the printer is also called a thermal printer.

As long as the temperature is high, the paper will turn black, and the heat generated by the fingernails can char it and turn it black. It's not just the computer receipts in the supermarket, it's a lot of fax machines.

Printers are also made of such materials.

And this thermal paper.

Printing is actually a method of printing handwriting, the ink is not on the printer nozzle, but on the paper, the basic principle of this thermal paper is a chemical reaction.

This principle is: it uses a layer of film to separate the colorless acid reagent of the two color development reactions, when the hot print head crosses a specific area, the film is scalded, and the two substances have a color development reaction, so we see the handwriting above, the advantage of this method is that there is no need to change the ink cartridge, and the disadvantage is that the handwriting will slowly disappear after a long time.

Or when the handwriting touches the alkaline substance, it is easy to produce a chemical reaction to make the handwriting disappear, whether it is a supermarket receipt, a credit card slip, or a movie ticket, etc., it is the way to print on thermal paper, and the document needs to be stored for a long time, it can not be printed with thermal paper, he and the thermal paper method is the opposite, the ink is on the nozzle, and the paper is ordinary paper, we usually see this way in the copy shop, his advantage is that the storage time is long, And the disadvantage is that if the ink runs out, the cartridge needs to be replaced.

This is why the ticket has black marks when scratched with a fingernail.

It's because of the material of the paper, which is called thermal paper, (composed of carbon). The printer is called a thermal printer. As long as the temperature is high, the paper will turn black.

Because there is black on the nails, and the paper is easier to color.

It may be because of the paper, different paper should have different effects.

Because it is a thermal paper, the fingernails are rubbed and rubbed to release heat.

The thermal paper and the nail heat up after rubbing, leaving marks.

The receipt is made of thermal paper, and it will turn black when heated.

The material on the receipt is relatively easy to hang up.

She gets dark just by feeling the temperature.

This is because his paper is special.

Nails heat up when rubbed, leaving marks.

The shopping receipts in the supermarket are thermal, and the manufacturing principle of thermal paper is to coat a layer of 'thermal paint' on high-quality base paper. When printing, the printer's stylus heat melts the filler, so that the dye and the developer come into contact, and under the action of the developer, the dye changes chemically, from colorless to black or other colors, and displays information on the paper. Bisphenol A is one of the components of the developer.

In addition to supermarket receipts, thermal paper is also used for POS receipts when swiping credit cards, ATM deposit and withdrawal vouchers, as well as taxi receipts, lottery tickets, parking lot receipts, fax papers, etc.

Bisphenol A on thermal paper is harmful to the human body, and there are two main ways to act on the human body: one is through the mouth and nose to intervene, and the other is through the pores to enter the human body. Excessive exposure to BPA can indeed be a health hazard.

However, the toxicity of bisphenol A is not very large, and the statement that holding a shopping receipt in your hand can cause bisphenol A poisoning and causing cancer is a bit exaggerated, so there is no need to worry too much. Of course, it is necessary to have less contact.

It uses thermal paper. It will change color above 70 degrees...

The production principle of thermal paper is to coat the ordinary paper base with particulate powder, the composition is colorless dye phenol or other acidic substances, separated by a film, under heating conditions, the film melts, and the powder is mixed to develop a color. The handwriting on the thermal paper is unstable and easy to fade, making the content of the document illegible.

When the thermal paper is placed in an environment above 70 degrees, the thermal coating begins to change color. The reason for its discoloration also starts with its composition. There are two main types of heat-sensitive components in thermal paper coatings:

One is a colorless dye or a hidden dye; The other is a chromogenic agent. This type of thermal paper is also known as two-component chemical thermal recording paper. Commonly used as a colorless dye is mainly:

Crystal violet lactone (CVL), fluorane system, colorless benzoylmethylene blue (BLMB) or spiropylpyran system of triphenylalkyl phthalide system. Commonly used as a chromogenic agent is mainly parahydroxybenzoic acid and its esters (PHBB, PHB), salicylic acid, 2,4-dihydroxybenzoic acid or aromatic sulfone.

After the thermal paper is heated, the colorless dye reacts with the chromogenic agent to produce color, so when the thermal paper is used to receive the signal on the fax machine and print or directly print with the thermal printer, ** is displayed. Since there are many varieties used as colorless dyes, the color of the handwriting displayed is different, such as blue, fuchsia, black, etc.

The printing equipment and paper of this kind of receipt belong to thermal printing. The black line is drawn on the nail because the nail rubs against the paper, which increases the temperature of the contact surface, thus showing the black line. (That is, the temperature generated by rubbing your fingernails against the paper is not lower than 60).

Thermal printers.

The principle is that a transparent film is applied to a light-colored material (usually paper), and the film becomes dark (usually black, but also blue) after heating the film for a period of time. The image is a chemical reaction in the membrane through heating.

and generated. This chemical reaction takes place at a certain temperature. High temperatures accelerate this chemical reaction.

When the temperature is below 60, it takes a considerable amount of time, even up to several years, for the film to become dark; At a temperature of 200 °C, this reaction is done in a matter of microseconds.

1. All that paper is called thermal printing paper, and thermal printing paper will turn black as long as the temperature is high. The heat from a fingernail can charring him and turning him black.

It is made of the same material as fax paper.

1. Check the thermal paper. Thermal printers must use thermal paper, and only the smooth side of thermal paper can be printed. Here's a little trick, with a slight scratch with your fingernail, the black scratch is the side of the thermal paper that can be printed.

In addition, thermal paper also has a shelf life, it is best to understand clearly before buying, once it expires, it will also lead to inability to type, judge whether it is expired or not, the same is to use sharp objects to scratch, no color is expired.

2. Check the print head. The thermal print head needs to produce high temperature to make the thermal paper image, so do not touch the thermal head directly with your hands, otherwise it is easy to burn. To judge whether the problem of the thermal print head is not, you can see whether the printed receipt is blurred, if it is usually the thermal head is defaced, you can gently wipe it with an alcohol sponge, if it is still blurry, you need to replace the thermal sheet.

3. Check the printer drum. When printing, you need to press the thermal paper firmly with the help of a roller, if the cylinder is loose, it will cause the thermal printing needle to be in poor contact with the thermal paper, and you can't type. At this time, you can open the lid and check whether the drum is pressed against the paper.

Analysis of the possible causes of the failure:

1. Determine whether the purchased thermal paper is a special thermal machine printing paper, judgment method: scratch it on the paper with a fingernail or sharp object, there will be black marks, as if written with a pencil on the white paper, if there are traces, it means that the thermal paper paper can be purchased, otherwise try to change the thermal paper.

2. The pressure of the printer drum is not necessarily normal when the thermal paper enters and exits normally, disassemble and check whether the cylinder is pressed on the thermal paper surface when the printer is working, otherwise the print head will not be able to contact the thermal paper, and it will not help how it heats up.

3. If the thermal printer is in the form of a ribbon, it is necessary to check whether the ribbon can be transferred normally when the printer is working, and if not, try to replace it with a new one.

4. If the possibility of the above three reasons is ruled out, it is very likely that the print head of the thermal printer is broken, and there is no way to work and print, so it is recommended to replace it with a new one.

Because you are using a thermal printer, you must use a special thermal printing paper, which can undergo a specific chemical reaction when heated, otherwise it will not be possible to type on the general printing paper.

There is also a situation where the thermal paper is not put backwards.

First of all, there may be a problem with the ink, it may be that the head of the print is knotted, and it can be covered with hot water a little, or it may not be set up.

In the printer settings, you should choose what ink to use, if you use black, choose black ink, color ink, restart and try again.

It's really not good, I guess it's a printer problem.

Generally speaking, customers buy more things, and the ticket inspector does not look good for a false mountain item to check You Chang right, and use his fingernails to draw a line on the shopping receipt, on the one hand, it is to simply confirm what the customer has purchased, and on the other hand, it is to prevent someone from entering the supermarket again to take something and reuse the checkout receipt.

The mimeograph was not dry, and a line appeared as soon as it was drawn

I have done supermarket loss prevention, every day.

The one on the first floor can also be a satisfactory answer? He said that the oil was not dry, so why could the white place still be scratched. It has something to do with the material of the paper.