What is the magical principle t匠聽hat the printer can print 嗎中millions of colors with 民離only four inks?
The core lies in the print head. There are a large n輛如umber of head distributed on the shower head湖去, and each head is thinner than a hair. The head are designed t要藍o be wide at the top and narro話我w at the bottom, which creates a n子藍egative pressure that prevents in數遠k from leaking. Once 答兵printing starts, the upper heating r吧紅esistor will heat the temperature to 10近可0 degrees within 0.00001 second. The視懂 high temperature evaporates the nearby現請 ink and forms air bubbles. The花跳 air bubbles act as p靜很istons to push the lowe她上r ink out of the ink droplet湖風s. Due to the viscosity a 雪拿main drop and a trailing d日西rop are formed. They fall 錯路at a speed of ten meters per se但錢cond, and the head is one millimeter a腦些way from the paper, so it only take和美s one ten-thousandth of a sec房音ond to reach and be absorb她老ed by the paper in a very short t時但ime. The head is connected to the p微村rinter through a hose, the belt a腦用nd pulley are driven by a ste車劇pping motor to move the head, and a shaft stepper is added to mov子飛e the paper. This is the basic struct話火ure of the printer.
How to print colorful images with four inks?
You might think of using a red-gr些司een-blue mix. Let's do a s志校mall experiment firs費嗎t. If you add red and green flashlight作車s together, you will get yellow when mixed, bu學拍t if you mix red and gree風師n inks, you will get a very cloud懂用y yellow. In fact, this is the differ些唱ence between additive 南票color mixing and subtractive color mi愛從xing. For self-illumina男爸ting shades, mixing two colors wi在快ll increase the brightn頻錯ess, and the ink itself will 醫遠not emit light. We can see the col鐵吃or of the ink becaus跳火e the light hits the ink 日舊first, and when it is refl去黑ected to the human eye, this pr數音ocess will filter out part of i城化t. For a better understanding, 村媽we zoom in on the in飛拍k droplet to a microscopic perspective.短員 If the green molecules in the lower音師 layer want to reflect green 下湖light, they must pen醫刀etrate the green and站笑 red molecules in the upper layer, 舊樂but this process will be 東站blocked by the red molecu又喝les, and black will be produc快木ed in this area. Likewis刀線e, the red molecules in the low會內er layer are blocked by the g制女reen molecules in the upper laye日通r, and the resulting blac地小k is what causes the輛校 yellow to become cloudy媽店.
To give another popular example, the聽場 gray hair we see with the naked e廠身ye is actually the result of mixin和是g white and black hair, so 門店obviously, the three prim睡明ary colors of red, green and 頻區blue cannot be directly used o制和n the printer. The solu西算tion is simple, just北弟 replace red, green and b媽綠lue with complementary c長舊olors, cyan, magenta and yellow. 站船When the nozzle releases a dropl廠門et of cyan ink, follow討化ed by a droplet of yellow制還 ink quickly, the two mix to就的gether to create the heady green color. Th國風e diameter of the mi兒公xed ink droplet is only 0.05 mm, 著舊and various colors can be obtained白民 in this way.
What if I want a lighter green?
In fact, as long as th農西e spacing is increased, a light我離er green can be obtained, and vice ve腦但rsa, it will become darker, 河鐘but the spacing is always limited.
What if you want a darker green空術?
At this time, black ink comes in h女歌andy. Mixing black into gree這費n ink droplets will result in dark gre森的en. The more black you mix, the darker 西嗎the green will be. So as long a飛秒s you use 4 colors of CMYK, y村討ou can print hundreds o章就f colors at most. Tens of thousands of現通 colors, and an A4-sized photo can eve離員n have hundreds of millions of ink公東 droplets. I have to 影靜admire the wisdom of human bei河喝ngs.
