Why the printed image of ECG machine is not clear

Electrocardiogram, a kind of processing paper used with ECG machine. First coat a layer of carbon black on the base paper as the base, and then coat a layer of white paint to make its surface look the same as ordinary white paper. Then it is printed with coordinate grid. When the "hot head" of the electrocardiograph contacts with the paper surface, the coating is melted, showing black lines, and the corresponding wavy lines are obtained.

Why should I use heat-sensitive paper for ECG paper?

1Convenient replacement -- the paper can be replaced without opening, which is very important for medical equipment.

2. Simple structure and high reliability -- the heat sensitive paper saves the trouble of replacing ink paper, while the heat source is fixed and there is only relative sliding between the paper during printing, and the stability and reliability are guaranteed.

3. The principle is similar -- the principle of thermal printing is also consistent with the principle of (change of body surface potential with time) embodied in ECG.

So why are the printed images of some electrocardiographs not clear?

There are usually the following reasons:

A. The two copper shafts on the cover are worn

B. The print head is damaged

C. The procedure is disordered, and the thermal printing paper used is expired, or the quality is too poor, wet, etc

D. The print head has been used for a long time, and the print head is dirty or dirty