What is the magical principle that the件知 printer can print mill跳兵ions of colors with only four 通工inks?
The core lies in the窗國 print head. There are a large number of head distributed on the shower he為高ad, and each head is thinner than a有術 hair. The head are designed to be wid姐我e at the top and narrow at the bottom, 我請which creates a negative pressur文但e that prevents ink from l請刀eaking. Once printing 票一starts, the upper heat厭樂ing resistor will heat 小輛the temperature to 100 deg老什rees within 0.00001 seco就動nd. The high temperature ev低黑aporates the nearby ink and for化是ms air bubbles. The air bubb輛懂les act as pistons t費生o push the lower ink out of the 土木ink droplets. Due to the viscosity a ma請村in drop and a trailing drop ar銀事e formed. They fall at a speed of ten 站知meters per second, and the head is one millimeter away fro討員m the paper, so it on低海ly takes one ten-thousandth of a離鐵 second to reach and be abs學還orbed by the paper in a very short路話 time. The head is connected to 書下the printer through a hose, the從著 belt and pulley are drive雪女n by a stepping motor to move the民拿 head, and a shaft stepper is added to mo計志ve the paper. This is the basic紅醫 structure of the printer.
How to print colorful images with four inks?還制
You might think of using a red-green-bl銀飛ue mix. Let's do a small expe鄉愛riment first. If you add red能科 and green flashlights together, you&nb話討sp;will get yellow when mixed, but if我光 you mix red and green inks, you will去在 get a very cloudy yel在兒low. In fact, this is the diffe腦花rence between additive房裡 color mixing and subtractiv男草e color mixing. For self-年綠illuminating shades, mixing two colors吃秒 will increase the brightness我家, and the ink itself 鐘短will not emit light. We can see the 白和color of the ink bec子得ause the light hits the ink first,刀河 and when it is reflected to the human 街草eye, this process will 嗎樹filter out part of it. For a better und長行erstanding, we zoom in on the ink dr知議oplet to a microscop區短ic perspective. If t關算he green molecules in the山行 lower layer want to reflect坐知 green light, they must penetrate the g喝木reen and red molecules in the upper lay議風er, but this process will be bloc花樂ked by the red molecules她風, and black will be produced in公山 this area. Likewise, t路謝he red molecules in the lower 問報layer are blocked by the green mol對亮ecules in the upper layer, and the res愛文ulting black is what causes the拍明 yellow to become cloudy.
To give another popular example姐大, the gray hair we see 高對with the naked eye is actually the resu城師lt of mixing white and 數媽black hair, so obviously, the three影中 primary colors of red, gree爸錯n and blue cannot be 都爸directly used on the printer. The sol海站ution is simple, just rep大城lace red, green and b醫路lue with complementary微月 colors, cyan, magenta and yellow很厭. When the nozzle releases a drop來來let of cyan ink, followed 裡我by a droplet of yellow雨近 ink quickly, the two m著朋ix together to create the heady green color. The diameter微匠 of the mixed ink droplet i街離s only 0.05 mm, and various color刀對s can be obtained in this way.
What if I want a lighter green?
In fact, as long as the spacing is inc風放reased, a lighter gr章女een can be obtained, a上地nd vice versa, it will become darke上司r, but the spacing is always limit外喝ed.
What if you want a darker gr有懂een?
At this time, black ink 麗鐵comes in handy. Mixing black 得請into green ink drople紙問ts will result in dark green. The mo話化re black you mix, the darker間票 the green will be. So as 著離long as you use 4 colors of CMYK, 窗這you can print hundreds of colors at mos費低t. Tens of thousands of co金少lors, and an A4-sized photo can even村我 have hundreds of millions o哥中f ink droplets. I have to a會舞dmire the wisdom of human bein老新gs.
