ITMI970481A1 - DEVICE FOR OPTICAL AND MAGNETIC READING OF SMALL DOCUMENTS SUCH AS BANK CHECKS, EQUIPPED WITH OPTICAL SENSOR AND HEAD - Google Patents

Description

Description of the device

The present invention relates to a machine for the optical and magnetic reading of small documents such as for example bank checks or payment bills or more generally all those documents which have imprinted a magnetic ink recognition code.

The main problem of known machines of this type is the different speed required for the acquisition of the optical signal typically coming from CCD sensors (Charge Coupled Devices) and for the acquisition of the magnetic signal from magnetic heads. The need to read the document to be processed at two different speeds has led many to solutions that provide a first reading phase at the optical or magnetic speed and a second phase at a different speed with two paths that are different and linked. Machines of this type are consequently necessarily larger since they have to allow the concatenated and in any case different optical path and magnetic path.

The present invention therefore brilliantly solves the problem of the different reading speed by allowing the document to pass in front of the optical sensor at the speed required by the optical acquisition and then return back in the opposite direction to pass in front of the magnetic sensor at the speed required by the magnetic reading.

Figure 1 represents the schematic diagram of the document processing principle seen in plan.

The document to be processed is inserted from the right side {Fig.1.1) and accelerated up to the magnetic reading speed in order to pass in front of the magnetic reading head (Fig.1.4) at the necessary speed and for the entire length of the document. The most common known standards in the banking sector that define the structure and characteristics of characters that can be read with magnetic acquisition techniques are the CMC7 and E13B. In order to understand the need to push the document at a certain speed not lower than a certain value in front of the magnetic head, we specify that the amplitude of the signal detected by a sensor that measures the difference in magnetic flux of a magnetized object moving in front of a it also depends on the square of the speed; the reading and recognition techniques developed to date give good results when the document dragging speed is about 1 meter per second.

After the document has passed completely in front of the magnetic head, it is stopped and restarted in the opposite direction. The length of the parking path (Fig.1.5) depends on the maximum document length admissible for processing with this machine.

In the second reading phase, the document is passed in front of the sensors for optical reading for the front (Fig.1.2) and for the back (Fig.1.3) at a different speed and lower than the magnetic reading speed. In the case of optical reading, the image quality is inversely proportional to the speed at which the document scrolls in front of the sensor. The sensors used are based on CCD technology (Charge Coupled Devices) which accumulate signals as a function of the quantity of photons that affect their surface, which is proportional to the intensity of light used and the exposure time. The exposure time is instead inversely proportional to the document drag speed.

After optical reading, the document is returned to the starting position (Fig.1.1).

For the sake of simplicity, we have described the phases of magnetic and optical reading in a determined sequence but the invention also concerns the application which provides for the optical and magnetic reading in the reverse sequence to that described.

In conclusion, the present invention is a brilliant solution for carrying out the optical and magnetic reading of documents which reduces the dimensions of the device.

For completeness of description, we report in figure 2 the line drawing of how we made the first prototype.

Claims (4)

Claims 1. Device for optical and magnetic reading of small documents such as bank checks, equipped with optical sensor and magnetic head capable of carrying out optical and magnetic reading at two different speeds, repeating the same path first in one direction and then in opposite way. 2. System as in point 1 which first carries out the magnetic reading and then the optical reading. 3. System as in point 1 which first carries out the optical reading and then the magnetic reading. 4. System as in point 1,2 or 3 which is inserted in a document processing machine with other functions.