Video from Lesic - Inkjet Printers | The interesting engineering behind them

[Lelopes]

A very simple way to teach about it.

 

[Ink stained Fingers]

The animations are pretty nice but there a few things I don't like. It's all about HP printers so piezo printheads are not mentioned as an alternate way to get the ink out of the nozzles. That's an omission - fine - but showing the resistors causing the heat pulsed to evaporate the ink as a wire coil is just wrong, those resistors, and there are plenty of them - as many as nozzles - are very short tracks of a metal resistive film with electrical connections. Colors are typically defined by a triple of numbers - RGB or CMY or some other methods - there is no black needed at all , and black ink is not added to create darker colors as shown, this is limited to a rather small range at the very bottom of the color space - if the black ink is available at all. Most colors - including darker ones are just created from a mix of the CMY inks, but a saturated mix of CMY does not create a good black - it is more a very dark gray with a rather strong hue, an effect visible when only CMY is used by 4 color printers on glossy papers. And that's the range where the black ink gets added - if available at all as a dye black, this shifts the blacks - and other almost black colors - more into the neutral range; and it's just a pretty wide range of HP printers which don't use the black ink for photos on glossy paper - the black ink in those printers only prints text on copy or matte papers.
Canon has overcome such limitations with 2 black inks - matte and photo black - in lots of their printer models with 5 inks total.

 

[PeterBJ]

An artist mixes colours on his or her palette before applying them to the canvas. The inkjet printer doesn't mix colours by printing the dots on top of each other, instead they are printed side by side. Here is a post showing this and also showing that printers having a dye (photo) black only uses it in the darkest areas.

 

[The Hat]

I found this demonstration very very wide of the mark, they suggested you can’t use Red, Blue and Green ink to print colour graphics, that balderdash, of course you can, because when used with the correct software it can produce a vast range of alternative colours, that’s the nature of Profiles..

They also say the ink come out of the nozzle but leaves an air bubble behind it, that is also incorrect, no air enters the nozzle chamber, because there is no void left behind the expelled ink, and their positioning of the heating resistors should be next to the ink outlet not miles from it. They should have consulted with Epson..

A Photo App sends RGB information to your printer, where the software converts that to the on board CYM + K inks to produce colour graphic, it’s not the inks that do the colouring it’s the special placement of the individual colour droplets.

They also said an ink colour drop is placed on the paper and another is placed on top of it to get a different colour, that is also wrong, the basic workings of an inkjet is to place ink droplets beside each other, not on top..

Ink spacing plays a huge part in producing every colour, but they failed to mention the most critical part of all, I.E. the fifth colour, White, because without the white background inkjet colour printing cannot work..

In short I found this video very bad (Fake News), because they used two different colour sources to hoodwink the viewer into their way of thinking because Additive and Subtractive colours should never be used to describe inkjet printing..

My two cent worth..

 

[Ink stained Fingers]

The video explains how the ink drops leave the nozzles...... but if you want to know a little more what is happening there rather have a look here, the video does not tell you the complete story

https://ris.utwente.nl/ws/portalfiles/portal/6085963/thesis_Wijshoff.pdf

Have a look to chapter 4 - Drop Dynamics - starting at page 81,

the thesis deals with a piezo printhead but once the ink is accelerated - by heat or piezo activation - the physical details with the moving ink are the same. And pp88 describe in detail what happens with the meniscus.

 

[Lelopes]

Come on guys, of course, this is a simplistic explanation, what would you expect from a few minutes video targeted to those that know nothing about printers .
The video isn't forming new printer technicians, but your dumb friend just asking about printer principles is not going to open the Wijshoff's Thesis on page 81 to get to know a bit more about his new machine. I think we are all being a little too harsh on something that we are obviously not the target consumer.

 

[Ink stained Fingers]

Why should somebody 'knowing nothing about printers' being interested how satellite droplets form, and some of the 'simplistic' explanations are not just simplistic but wrong as explained in various postings so there is enough reason for a negative verdict.

 

[The Hat]

what would you expect from a few minutes video targeted to those that know nothing about printers .

Just because someone is ignorant of the workings of inkjet printer doesn’t mean they can be further mislead.. Facebook is the proper place for that sort of beguilement… Sorry..