GB2331585A

GB2331585A - Damp meter

Info

Publication number: GB2331585A
Application number: GB9724449A
Authority: GB
Inventors: Timothy Charles Peter Fry
Original assignee: RIDGEMILL BUSINESS SYSTEMS Ltd
Current assignee: RIDGEMILL BUSINESS SYSTEMS Ltd
Priority date: 1997-11-19
Filing date: 1997-11-19
Publication date: 1999-05-26
Also published as: GB9724449D0

Abstract

A meter for measuring dampness in paper comprises two plate-like electrodes 4, means for passing or positioning paper between the electrodes, electrical driving means, and a display 6. The means for passing or positioning paper ensures that the paper is in contact with both electrodes. The electrical driving means measures the resistance between the electrodes and the output from said electrical driving means is input to the display. Indicating means is incorporated in the display so that a reading indicating the water content of the paper can be given.

Description

DAMP METER 2331585 The present invention relates to meters for measuring

the dampness in paper, and in particular, but not exclusively, for use in paper handling machines.

Paper handling machines and in particular, but not exclusively, photocopiers, printers and telefax machines are dependent on the type, quality and dampness of paper that goes through them. Damp paper is of particular concern as it can cause a reduction in copy quality and jamming in the machine. Damp paper can often be noticed by the way it curls on exiting the paper handling machine. In order to aid in the diagnosis of damp paper problems in the area of paper handling machines, the present invention provides a meter for testing paper for dampness for both machine engineers and machine users.

According to the present invention there is provided a meter for measuring dampness in paper comprising; two plate-like electrodes, means for passing or positioning paper between the two plate-like electrodes, electrical driving means for measuring the resistance between the plate- like electrodes, a display receiving the output from the electrical driving means and having indicating means to show the dampness measured in the paper. For the purposes of this specification, the term, plate-like electrodes is intended to cover curved plate electrodes or flat electrodes that are curved, as well as flat planar electrodes.

Preferably, the electrical driving means includes a power source and a driving circuit for measuring the resistance of the paper between said plate-like electrodes. Conveniently, a voltage from the power source is applied to one of the plate-like electrodes, and the other plate-like electrode picks up current which has passed through the paper.

In a preferred embodiment, the meter is incorporated in a portable casing having a top section and a base section that are moveably connected to each other, both plate-like electrodes being planar with one electrode being disposed on the upper outer surface of the base section and the other electrode being disposed on the lower outer surface of the top section such that the flat surface area of the plate-like electrodes are substantially aligned with one another so as to meet face to face in one position of the top and base sections and to be separated in another position. The display is conveniently disposed on the upper outer surface of the top section.

Preferably, the power source is a battery. It is a preferred feature that a battery condition indicator is located on the outer surface of the portable casing.

In another embodiment the meter is incorporated within a paper handling machine having a pair of paper feed rollers whereby, along at least part of the circumference of said rollers, the plate-like electrodes are incorporated as inserts, there being one plate-like electrode disposed on each 15 paper feed roller.

In a further preferred embodiment the driving circuit includes amplification means for amplifying the signal from the pick up electrode. Ideally, smoothing means are provided for smoothing the signal input to the amplification means. Preferably, calibration adjustment means is provided for calibrating the signal output from said amplification means, and the signal output from said calibration adjustment means is input to the display.

It is a preferred feature that the display is a moving coil meter display 25 having markings and a needle which constitute the indicating means.

Alternatively, the display consists of a number of electrically illuminable elements which can be selectively illuminated to indicate a corresponding scale reading. Preferably, the electrically illuminable elements 30 are light emitting diodes.

Embodiments of the invention will now be described in more detail. The description makes reference to the accompanying drawings in which:

Figure I is a perspective view of a meter/device according to the 35 present invention as incorporated into a portable damp meter.

Figure 2 is a side plan view of the meter/device shown in figure 1, Figure 3 is a schematic diagram of electrical driving means used in the meter shown in figure 1, and Figure 4 is a perspective view of feed rollers of a photocopier incorporating the present invention.

In figure 1 there is shown a portable meter 1 for measuring dampness in materials, the meter being shown in an open position. The embodiment shown is for measuring the dampness in photocopier paper but it could be used equally well for other papers or indeed for other materials. The meter 1 has a hollow outer casing in which electrical driving means is housed, the electrical driving means being shown in more detail in figure 3. The outer casing has a top section 2 and a base section 3 which are connected to each other by way of a hinge 5 at one end. Each section 2, 3 has a plate-like electrode 4 disposed on the opposite end to the hinge 5, such that the plate-like electrodes 4 lie with their surface areas substantially aligned with each other such that when the top and base sections 2, 3 are closed together the electrodes 4 meet in face-to-face contact. A display 6 from which readings are taken is located on the top surface of the top section and a battery condition indicator 7 is also located on the top surface of the top section 2, adjacent the display 6. An on/off switch 8 is also provided and is disposed on the top surface of the top section 2 adjacent the battery condition indicator 7. In this embodiment the plate-like electrodes are circular in shape and made from a conducting metallic material, however, other shapes and conducting materials could be used.

Figure 2 shows the portable damp meter in an operational position when in use. To use the meter, a piece of paper 30 is placed between the platelike electrodes 4 and force is exerted on the ends of the base and top sections 2, 3 remote from the hinge 5, which causes the said ends of the base and top sections 2, 3 to move towards each other such that the paper is clamped between the two plate-like electrodes 4. This action completes an electric circuit, an example of which is shown in figure 3, and allows the resistance of the paper to be measured. The dryer the paper the more resistive it will be to 4 passing current, and this property is used to determine the moisture content of the paper.

The electrical driving means is shown in more detail in figure 3 and includes a 9 volt battery and driving circuit for the meter. A positive 9 volt D. C. voltage is applied to one of the plate like electrodes 4, and the other electrode 4. is used to pick up the current which passes through the paper. Transistors Q 1, Q2, a diode D 1 and a resistor R2 constitute a common collector amplifier 40, the output from which is fed through a resistor R3. A capacitor Cl, and resistors R 1, R2 smooth the signal from the pick up probe 4. before the said signal is fed into the common collector amplifier 40, said smoothing components also serving to stabilise the reading indicated on the meter display 6 shown in figures 1 and 2. A further resistor R4 is provided in the circuit for the purpose of calibration adjustment and the signal output from said resistor R4 is input into a moving coil meter 7 from which readings are taken. Also incorporated in the driving circuit is an onloff switch swl.

The display 6 is as shown in figure 1 and consists of a moving coil meter display having a needle and meter fancier with calibration markings which may show dry, moist and wet readings, as well as a battery condition indicator, but could also show numerical values for comparison with a list of associated conditions.

Figure 4 shows the present invention as used in a paper handling machine, in this case a photocopier. For the sake of clarity only a section of a photocopier incorporating the present invention is illustrated- The electrodes are incorporated on paper feed rollers 11 as curved plate electrodes 13, inserted along the circumference of said rollers 11. Signal transmitting means 15 lie inside the paper feed rollers 11, and connect the electrodes attached at one end, to the driving circuit 50 attached to the other end. The output from the driving circuit 50 is input to a display panel 20 having indicating means from which a reading can be taken.

In use, each paper feed roller 11 rotates in different direction to the other so as to propel the piece of paper 30 to the next stage of the photocopying process within the photocopier. During rotation both curved plate electrodes 13 contact the paper 30 thereby completing the driving circuit of the damp meter. Voltage is applied to one of the curved plate electrodes 13 by signal transmitting means 15, the other electrode being used to pick up the current that passes through the paper 30. The rotating motion of the paper feed roller 11, and hence the electrodes 13, enables the resistance of the paper 30, and therefore the moisture content, to be measured via the driving circuit. The moisture content of the paper is displayed by indicating means on the display panel 20, and so a reading for the dampness of the paper can be taken.

It will be appreciated that the embodiments of the present invention as described above are given by way of example, and other modifications will be apparent. Other analogue driving circuits could be used and also, a digital driving circuit can be used instead. Also the number, size and shape of electrodes could be varied, and other conducting materials used for the electrodes. Other means for passing or positioning the paper between the electrodes could be used apart from roller or the moveably connected top and base sections 2, 3. The display 6 and battery condition indicator 7 could also be located anywhere on the top and base sections 2, 3.

Claims

1) 5) A meter for measuring dampness in paper comprising; two plate-like electrodes means for passing or positioning paper so that the paper is in contact with both plate-like electrodes, electrical driving means for measuring the resistance between the plate-like electrodes, a display receiving the output from the electrical driving means and having indicating means to indicate the dampness measured in the paper.

2) A meter as claimed in claim 1 wherein, the electrical driving means includes a power source and a driving circuit for measuring the resistance of the paper between said plate-like electrodes.

3) A meter as claimed in claim 2 wherein, a voltage from the power source is applied to one of the plate-like electrodes, and the other plate-like electrode picks up voltage which has passed through the paper.

4) A meter as claimed in any one of claims I to 3 wherein, the said meter is incorporated in a portable casing having a top section and a base section that are moveably connected to each other, one of the said plate-like electrodes being disposed on the upper outer surface of the base section and the other plate-like electrode being disposed on the lower outer surface of the top section such that the surface area of the plate-like electrodes are substantially aligned with one another, the display being disposed on the upper outer surface of the top section.

A meter as claimed in claim 4 wherein, the power source is a battery.

6) A meter as claimed in claim 5 wherein, a battery condition indicator is located on the outer surface of the portable casing.

7) A meter as claimed in any one of claims 1 to 3 wherein, the said meter is incorporated within a paper handling machine.

8) A meter as claimed in claim 7 wherein, the paper handling machine has paper feed rollers, along at least part of the circumference of said rollers the plate-like electrodes are incorporated as inserts there being one plate-like electrode disposed on each paper feed roller.

9) A meter as claimed in any one of claims 1 to 8 wherein, the driving circuit includes amplification means for amplifying the signal from the pick up electrode.

10) A meter as claimed in claim 9 wherein, there is provided smoothing means for smoothing the signal input to the amplification means.

11) A meter as claimed in claim 10 wherein, there is provided calibration adjustment means for calibrating the signal output from said amplification means, and the signal output from said calibration adjustment means is input to the display.

12) A meter as claimed in any one of claims 1 to 11 wherein, the display is a moving coil meter display having markings and a needle which constitute the indicating means.

13) A meter as claimed in any one of claims 1 or 2 wherein, the display consists of a number of electrically illuminable elements which can be selectively illuminated to indicate a corresponding scale reading.

14) A meter as claimed in claim 13 wherein the electrically illuminable elements are light emitting diodes.