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Differential Synchronization Sensor

IP.com Disclosure Number: IPCOM000079629D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Naylor, HE: AUTHOR [+2]

Abstract

This sensor allows differential sensing of charged drops during synchronization. Thus, common-mode noise signals (the charge voltage pulses) are severely attenuated and the electronics is much less noise sensitive.

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Differential Synchronization Sensor

This sensor allows differential sensing of charged drops during synchronization. Thus, common-mode noise signals (the charge voltage pulses) are severely attenuated and the electronics is much less noise sensitive.

Fig. 1 is a diagram of one form of synchronization sensing device which is somewhat noise sensitive, as well as sensitive to charged ink droplets. The noise sensitivity can be reduced simply by designing a sensor with a differential electronic sensing circuit. Thus, differential sensing allows significant attenuation of the unwanted common-mode noise signals.

Figs. 2a and 2b illustrate a differential sensor and its corresponding electronics, which is effective in improving signal-to-noise ratios. Note that like the sensor of Fig. 1, driven guard shields 1 and 2 are used in order to reduce effective input capacity. Also, like Fig. 1, grounded shields are used to provide further shielding. The differential structure of the sensor shown in Figs. 2a and 2b is made in layers of metal and plastic, just as is the other version.

In contrast with the sensor of Fig. 1, the differential sensor of Fig. 2a is split in two, that is, it is a dual sensor (I and 2). One-half of the sensor is located further away from the stream than the other half. This means L1 >/- 3L2. Typically, distance L1 is at least three times distance L2.

Since the two sensors are located in about the same place, they pick up essentially the same noise signal...