Inkjet Printing

Posted by PITHOCRATES - March 5th, 2014

Technology 101

A Sunday Afternoon on the Island of La Grande Jatte is similar to Ink Jet Printing

Stephen Sondheim and James Lapine created a musical based on the painting A Sunday Afternoon on the Island of La Grande Jatte by Georges Seurat.  Giving us Sunday in the Park with George.  Seurat used a technique called pointillism.  Where he painted dots of color.  Points.  Up close the eye saw only a mass of different colored dots.  But when you moved back from the painting the brain blended those dots together into an image.

This is the same technique our televisions use to recreate an image on the screen.  Using only the 3 primary colors of light.  Red, blue and green.  Different colors of phosphor are energized to glow.  Causing a combination of these three dots of phosphor to glow creates a pixel of color.  A screen full of different colored pixels creates an image.  It’s similar to inkjet printing.  Where a print head places dots of different colors on a piece of paper.  Much like George did in Sunday in the park with George.  Although an inkjet printer can do it faster.  And without destroying a relationship.

George painted one dot at a time.  So it took him a very long time to create an image.  —SPOILER ALERT—   So much time that Dot left him and had a baby with Louis the baker.  Leaving George alone.  A true suffering artist.  Who died young.  Never realizing that Dot’s baby was his.  Which gave us a second act.  A great musical.  With some of Sondheim’s best music and lyrics.  The original Broadway recording with Mandy Patinkin and Bernadette Peters should be in everyone’s collection.  Do yourself a favor and buy it.  Support the arts.  But I digress.

Droplets of Ink are shot out of the Print Head onto the Paper without any Physical Contact with the Paper

If you have a large art museum near where you live you can probably see a work of art done in the pointilism technique up close.  And if you do you’ll probably notice that the dots are rather big.  Unlike they are with an inkjet printer.  Where the dots are much smaller.  It’s the same technique.  Pointillism.  But it is much harder to see that with inkjet printing.  Why?

George painted with a paint brush.  And even when the bristles are smoothed into a point it’s still pretty thick.  And makes large dots.  An inkjet, on the other hand, doesn’t ‘brush’ on the ink.  It spits it on.  Droplets of ink are shot out of the print head, across an air-gap and onto the paper.  Without any physical contact.  The only physical contact with the paper is the roller that loads a sheet.  And the roller that advances the sheet.  While the print head glides above the paper.  Spitting droplets of ink.

Well, it doesn’t actually spit ink.  It boils it.  In the ink cartridge.  Which is a marvel of engineering.  For the ink cartridge not only contains the ink.  But it also contains the print head.  A few hundred holes where droplets of ink jet out of.  As well as a lot of copper etched circuits.  To take the information from the computer when printing a document.  And transferring it to the proper ink port.  Which are very, very tiny holes.  So tiny that the droplets they produce make for near photo-like quality compared to a pointillism painting.

The Ideal Gas Law tells us if we incrase the Temperature while holding the Volume Constant the Pressure Increases

The ideal gas law is PV = nRT.  Which can be solved such that P = nRT/V.  Where pressure (P) equals the chemical amount in moles (n) times the universal gas constant (R) times the temperature (T) divided by the volume (V).  A lot of information there.  But the only things we want to focus on are pressure, temperature and volume.  The ideal gas law tells us if we incrase the temperature while holding the volume constant the pressure increases.  Which is how inkjet printing works.

Each ink port has ink in it.  But the hole is so tiny that the ink in its normal state will not flow through it.  Because it’s too thick.  However, when you heat the ink to boil it into a vapor the pressure is so great that it pushes a droplet of ink out of the print head onto the paper to releive the pressure.  All of this happens in a fraction of a second in all of those hundreds of ink ports.  An electric circuit turns on.  Boils ink.  Forces out a droplet.  The electric circuit shusts off.  And the ink just used to print with is replaced with fresh ink.  Waiting for the next electric current to boil it.

Complex software and hardware to advance the paper and move the print head over the paper are all coordinated to place thousands of droplets of ink with each pass of the print head.  A black ink cartridge is used for text documents.  And a color ink cartridge (red, blue and yellow) is used to add color to a text document.  Or to print color images.  Doing the work of a thousand Georges.  Faster.  And with tinier dots.  So tiny that they are impossible to detect with the naked eye.  Unlike Seurat’s A Sunday Afternoon on the Island of La Grande Jatte.  But few printed items will look as good.

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Quill Pen, Dip Pen, Fountain Pen and Ballpoint Pen

Posted by PITHOCRATES - June 19th, 2013

Technology 101

The Quill Pen was nothing more than a Bird’s Feather and some Ingenious Thinking

The pen is mightier than the sword.  For while the sword can kill a person they cannot kill that person’s words.  Even the words ‘sword’ and ‘words’ are interesting in themselves.  For if you drop the ‘s’ from both you have ‘word’.  That thing that makes us human.  Putting our thoughts into words onto paper.  So that others can read these words.  And understand our thoughts.  Our ideas.  Our perspectives.  Our wisdom.  So we can pass these words down through the ages.  Or on to others in our current age.

The Egyptians, the Sumerians, the Harappa and the Nanzhuangtou all wrote.  A stylus on a clay tablet was probably the first form of writing.  Not quite the communications we have today.  But this writing gave us the four great ancient civilizations.  But only a select few wrote in these early civilizations.  No.  Writing didn’t really take off until much later.  And the introduction of the first great writing tool.  The quill pen.  Which was nothing more than a bird’s feather.  And some ingenious thinking.

What happens when you place a paper towel on a spill?  The towel absorbs the liquid.  By rising up into the paper towel.  This is capillary action.  And is the basis of the quill pen.  Without getting too technical molecules in a liquid are attracted to the surface of a round tube.  Everyone no doubt remembers seeing this in a high school chemistry class using a graduated cylinder.  That tall tube of glass we measured liquids in by reading the scale off of the glass.  The surface of the glass attracted and pulled up the liquid on the sides of the glass.  Forming a concave surface on top.  The narrower the tube the greater this pulling force.  And the higher this attraction will pull a liquid up the tube.

Thanks to the Dip Pen most Americans were Well-Informed and Literate at the time of the Civil War

A bird’s feather is hollow.  A long narrow tube.  When dipped in a well of ink capillary forces will pull this ink up the hollow tube of the feather.  And hold it there.  Not a long column of ink.  But enough to let us write words.  Before we did, though, we used a pen knife to cut a nib in the end.  You make a 45-degree cut across the bottom.  Then you cut again to remove most of the round cylinder.  If you were looking into the end of the feather and imagine the face of a clock you would remove everything from 1:00 to 11:00.  Or thereabouts.  So you are left with a flat-like extension from the tube of the feather.  You then cut the tip of this flat extension to get a nice chisel point.  Then, finally, you slice or score this flat extension of the tube from the tip of the nub to the tube holding the ink.  This allowed the ink to flow from the tube to the point.  As one wrote the ink at the tip would wipe off on the paper.  And when it did it would pull fresh ink from the tube reservoir above.

This was a remarkable tool.  And one we used for a very long time.  Roughly from the 6th to the 19th century.  This is what the scribes used in those monasteries when they translated all those Greek texts the Crusaders brought back to Europe.  Quills penned Magna Carta.  It’s what Shakespeare used.  It gave us the King James Bible.  The works of the Enlightenment.  The Declaration of Independence.  The U.S. Constitution.  And the Declaration of the Rights of Man and of the Citizen.  We used it that long because it was that good.  Simple.  And we only stopped using it when manufacturing techniques advanced to the point that could create the quill nib in steel.  Giving us the dip pen.  And once we did we said goodbye to the quill pen.

The dip pen was basically the quill nib made out of steel.  Only it was sturdier.  And didn’t require anyone having to become skilled with a pen knife.  We began manufacturing the dip pen around the 1820s.  Mass production techniques brought down prices.  Allowing anyone to write.  Even children with poor pen knife skills.  School desks had holes in the upper right corner.  To hold an ink well.  So children in school could dip their pens.  And put words to paper.  Literacy rates soared.  As did education.  Americans were probably not more informed and literate than they were at the time of the Civil War.  Thanks to the inexpensive and easy-to-use dip pen.

Penmanship and Cursive Writing were once Important Parts of the School Curriculum

The dip pen had a much shorter life than the quill pen.  Replaced by the fountain pen.  Pretty much the same as the dip pen.  Only with an internal ink reservoir.  Other advancements made the fountain pen portable.  Such as a retractable nib.  Or a cap that covered the nib.  Allowing us to slip the fountain pen in a pocket without ink staining our shirt.  We filled early reservoirs with an eyedropper.  Which was messy.  The next development was adding a mechanism that when operated drew ink up through the nib into the reservoir.  And a breather hole helped the ink flow to the paper by allowing air to enter the reservoir to replace the ink as it left.  Filling a fountain pen through the nib was neater to fill than using an eye dropper.  But still required an open ink well.  Which could spill or leave excess ink on the nib after filling.  The next advancement was an ink cartridge.  Removing the need to have an open well of ink.  Removing the chance of an ink spill.  And there was no excess ink on the nib after refilling.

The fountain pen was about as good as it got.  Until the ballpoint pen arrived.  Cheap.  Disposable.  Convenient.  And clean.  Up until the ballpoint pen the mechanics of the pen remained the same from the quill pen to the dip pen to the fountain pen.  They all had a nib with a slit that drew ink from a reservoir.  The ballpoint pen was a completely different technology.  Where we replaced the nib with a very small ball inserted into a point.  Hence ballpoint pen.  We make the ball from a very hard metal such as tungsten carbide and machine it into a perfect sphere.  The ball snaps into a socket in the point.  Attached to this nib assembly is an ink-filled plastic tube.  The ball fits so snuggly that it can’t slip out of the point or slip up into the ink reservoir.  And it holds back the ink from running out of the reservoir.  When you write you drag the point across the paper.  This rotates the ball in the point.  Bringing ink from behind the ball onto the paper.  Producing a very uniform ink line.

The ink pen created civilization.  By allowing us to put our thoughts into words.  And putting those words onto paper for others to read.  Penmanship and writing in cursive were once important parts of the school curriculum.  As they were the gateway to literacy and education.  But that has all changed.  Few people write today.  Instead they type.  Or text.  Bastardizing our words into shorthand gibberish.  A long cry from the elegant words of William Shakespeare.  Or the impassioned words of the Declaration of Independence.  Where we raised our words to the level of art and put them to paper.  Ushering in the golden era of civilization.  Where we were our most human.  Expressing our thoughts.  Our ideas.  Our perspectives.  And our wisdom.  Replaced today with truncated efficiency.  As we dehumanize ourselves to live in a digital world.

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