ink density and conductivity measurement tool

[Fist]

Which tools do you use for measuring ink conductivity?

 

[Asures]

Ink Density - Hand Held Spectrophotometer (Try X-Rite or Techkon)

Fountain Solution Conductivity - pH and Conductivity Meter (Try Myron L or Hannah)

Is this for pressroom Q.C. purposes or for ink manufacturing? I'm familiar with printers adjusting pH of inks within Flexo applications but not conductivity.

 

[chevalier]

For density and spectrophotometry the new Techkon devices are definitely superior to the X-rite. I have the X-Rite exact and a vendor brought in his new Techkon recently. It was instant buyers remorse for me.

 

[D Ink Man]

Why is this in this forum?

 

[Fist]

Why is this in this forum?

Printing with HP Electro ink requires a conductivity measurement tool. Because this relates to digital printing, I was under the impression that this was the best place to ask the question.

 

[Deleted member 16349]

Printing with HP Electro ink requires a conductivity measurement tool. Because this relates to digital printing, I was under the impression that this was the best place to ask the question.

The term conductivity is probably not the right term for what you want. Conductivity tends to be used with solutions.

I would guess that for your need of electrical conductivity, one would measure electrical resistance in ohms with a multimeter that can measure ohms in the right range. The higher the ohms value, the lower the conductivity. Or one might use 1/ohms to relate to more directly to a conductivity value.

Electrical resistance of a printed line of ink would be related to its length and cross sectional area and to the electrical properties of the ink itself. Longer length will result in higher resistance and so will a smaller cross sectional area of that printed line.

I would also expect that there are some standards used now in the industry for printed electronics that can give some guidance.

 

[D Ink Man]

Thank you.

I enjoy learning as much as sharing my expertise. Everyone can trust in that.

D Ink Man

 

[Schnitzel]

Erik, in Indigo presses conductivity is measured inside the ink tank. That's the term used by HP, anyway. In your explanation, is the measurement done on the printed sheet?

 

[Deleted member 16349]

Schnitzel, I was just talking in general terms. I do not work with printed inks that are used for printing electrical circuits.

Since the original poster was asking about conductivity, I was just suggesting what might be done. If the standard method for a specific ink is to measure it in the ink tank, that seems to be reasonable.

With printing electrical circuits, different inks are used. Some are conductors, others are non conductors and some are semiconductors. When testing conventional circuit boards, the measurements are done on the board. I guess for that reason it seemed logical to me that one should measure the conductivity of a printed ink on its substrate. That may be more of a test for how that ink performs when printed while the measuring of the ink in the tank might be better for just testing the ink.

There are issues between the electrical performance of the ink itself and how an ink will perform when it is printed. I have been told that printing electrical circuits with offset lithography is not so suitable because the water in the printed ink affects performance. If one looks at the printing technologies that are now being used to print electrical circuits, one sees flexo, gravure, inkjet, screen but hardly any offset. At this time, the available inks are not compatible with lithography. Maybe in the future.

I am just an interested observer in these new technologies. Being an engineer, I would tend to measure the performance of an ink in its printed condition and that is why I would suggest a direct measurement of the printed ink in some standard way.

It is an interesting field where a lot of development is taking place.

 

[chevalier]

I too, found this to be an opportunity to learn over at the HP website and found what I just learned quite interesting. I'm not understanding why you need to check this conductivity. Are you buying nonHP ink or is HP providing inconsistent ink or something?

 

[Schnitzel]

The ink pump has a conductivity sensor built into it (the electric board is submerged in the ink tank). The sensor might drift or lose its calibration, so you need an external measurement device to recalibrate it.

 

[JohnTheMathGuy]

Chevalier,

What sold you on the Techkon?

 

[chevalier]

Chevalier,

What sold you on the Techkon?

To be honest pretty much everything. The X-rite exact feels a decade old compared to the Techkon SpectroDens.

• Interface was much easier to use and useful
• Spot and scan measurement
• Supplemental software
• Speed
• LED vs. Tungsten backlight

I'm not a press operator but I thought that the SpectroDens was more intuitive (thus useful) than our Heidelberg ImageControl "Next Generation". We're stuck with the exact for a while. Once the unit(s) require repair I'll lobby to make the switch to Techkon one at a time.

 

[Dov]

Guys , your are missing the point here and drifting from the question.
Mr.Fist asks a very relevant question for somebody either just starting with an Indigo or that
is interested in buying one.
The Indigo presses are the only presses using a fluid toner.
this toner is conductiv in order to control it during the process.
How conductiv the toner is is called conductivity and it messured as here stated by 1/ohm
this unit is also known as mho or in ISO a simens symblised by the letters "Si".
The density which Fist was asking about is not the density on paper but the density in the tank (toner tank).
not to confuse with the OD (Optical density) (on paper).
To answer directly to Fist question :
you can meassure both with tools provided by HP.
if you have further questions dont hesitate to contact me in the forum or directly.
cheers

dov

 

[Austin12345]

Hi,

Densitometer : which is used to set uniform ink densities across the page. The densitometer is also used to ensure that the ink density level is not too light or heavy.

 

[Justin M]

Fist,

For the HP Indigo Presses, there's a sensor in the ink tank that measures the ink density and conductivity. Sometimes that sensor does need to be calibrated and you'll need a meter for that. HP sells an Ink Conductivity/Density meter. There's two different probes that attach to the meter and can measure these things. You'll have reach out to your sales rep if you want to purchase it. My company purchased ours for about $2000.

Justin

 

[RGPW17100]

We have 2 HP10000 and 2 HP7600. Because of the volume and the importance of getting machines up and running HP has provided us with a conductivity meter. The boards in the ink tanks I believe is the LCS board or the ITS has two plates of some kind of metal that measures the conductivity of the ink between the plates I believe in Picomhos or Pico Siemans. This measurement is critical to the application of the Indigo ink. The plate or PIP is charged with a negative 600 volts (if my theory is correct). A laser penetrates this voltage to certain depths changing the voltage to non image and image areas. The ability of the ink to carry a charge (conductance) determines how much ink will stick to the different voltages on the pip which is transferred to the blanket and then to the substrate. The calibration of these plates can drift and an external conductance meter is used to measure the correct conductance versus what the machine is reading. You then go into the sys tab and make the corrections to calibrate your ink tanks. If you are under a service agreement with HP their techs have access to one of these meters and can do the calibration for you.

 

[Mark Flanders]

HIya,

Old post, I know, but thought I's straighten this out...HP Indigo Ink is liquid and needs to have it's density and conductivity measured. (ink moves to the least negatively charged area, like Xerography) this is done automatically, but there are manual devices as well for calibration. These devices are for measuring the liquid ink for these qualities.
The X-rite densitometers, and such are for measuring the printed inks on the paper, which is essentially the same in offset and digital. All the best!

 

[chevalier]

So... an Ohm meter?

 

[Mark Flanders]

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