Same print heads, but different resolutions???? HOW?

[Nifty]

Friends,

I haven't looked into this very much, but from what I've heard / read it seems that many of the Pixma printers use the exact same printheads as the older "i Series" printers. Also it seems that the Pixma printers are suppose to have a better resolution and different ink consumption.

So, this begs the question: How?

Even with different electronics and instructions how can the same printhead, cartridges, and ink deliver different results?

 

[panos]

I think the printheads for the pixma series are manufactured in a process Canon calls full photolithography. Is that a part of the i series printhead manufactiring?

 

[kenban]

Only some of the printers use the same print head. Printers such as the iP5000 which is the only Canon I really have been hearing has better ink usage then the old i series. Mostly this is from the fact it is a 1pl print head unlike the real of the Pixma or the i series which are 2pl print heads. Also the iP5000 I think is the only Pixma printer with a higher resolution.

 

[cd187]

That is not so hard to believe, especially the increased resolution. As I understand things, when inkjet printer manufacturers refer to resolution, in dpi, they are talking about "addressable dots per inch" or drop locations per inch. For example, if the resolution is 600x600 dpi, that means there are 600 vertical and 600 horizontal locations the head can put an ink drop. This is controlled primarily by the head and paper feed drives. If the precision of those drives are increased, say going from 600 steps per inch to 1200 steps per inch, then the horizontal and vertical "addressable" locations will be increased, allowing for a theoretical 1200x1200 dot addressable resolution, a four-fold increase. So, keeping the same heads, you can still get a resolution increase.

Now, in each of the addressable dot locations, the printhead may deposit more than one color, say a cyan drop and a yellow drop to get a green dot in the addressable location. In addition, depending on the nozzle used and ink drop volume, you could end up with multiple size drops in a dot location. Something like a 5 pL cyan drop and a 2 pL yellow drop together. All inkjets use one form or another of this "dithering" pattern to produce all the colors from just a handful of primary ink colors. Depending on the precision of the head and paper drives, the ink drop volume amount, the type of paper used, the density and spread rate of the ink, and the dithering algorithm used, it is possible to use less ink with the same heads. As each drop of ink gets placed with greater precision, there should be less bleeding of colors, which should make for more vibrant colors. Historically, printer vendors would use different algorithms to produce brighter, more vibrant colors by dithering magenta to the yellow and cyan to the magenta to make the colors brighter and more saturated, especially in photos. On the other hand, this type of dithering renders a less than true color image. I was told this several a few years ago (about 2002) by several inkjet vendor reps. It was a direct response to customer complaints, who felt that some inkjet prints were dull and lifeless, however accurate the color. (Sort of like the current complaints when some consumers buy the current Epson pigment ink printers.) If the precision of the drop location can be increased and reduce color bleeding, then the colors can be more vibrant and the dithering algorithm can be adjusted to reduce the use of magenta with the yellow and cyan with the magenta for increased brightness, and reducing ink consumption in the process.

I could be wrong about all this, as I am not a design engineer. I am however, an electronics technician by trade with more than a few years experience, and too many hours in training seminars, hehehe. If someone else can explain this better, or simply knows about this, please correct me.

 

[Nifty]

Holy Cow!!! Great first post cd187! Welcome to the forum and thanks so much for posting.

I hadn't even thought about print head and paper movement, but that does seem like a feasible explanation.

I look forward to more of your posts!

 

[Endmukbud]

Oh, yup thats right "cd187"
The just doubled the resolution......by controlling the printhead motor
Like an example my XNU i320 have 2400 x 1200 resolution
Then my friend's Pixma ip 1000 have 4800 x 1200 resolution......In fact they have the same...precise.....printhead....

( I'll try to explain how did these things phisically happend )
did you notice that they usually only doubled the horizontal resolution ( ie..paper width ), rather than the vertical res ( paper length )....

There is an easy way to do this......( i found these after i crack up my print )

did you notice there is a small light behind your print head.....whenever you print something... ( i found it red light in my XNU, an blue on my HP )
and some a long stripped plastics which tie on one side to another side ( behind you printhead )
The long stripped plastic was the movement guider for printhead and the light was the movement sensor...i've count how much stripped lines on these plastics and there was about 1200 lines per inch....and seems printer cpu have a tricky way to doubled it...
1st they fire more than one ink "bullet" for each of these guider lines.....
( 1 bullet per lines = 1200 dpi, 2 bullet per lines = 2400 dpi, 3 bullet per lines = 3600 dpi, 4 bullet per lines = 4800 dpi, ...and so on ) seems HP do this with their PhotoRET machine but with 600 dpi guider instead 1200 dpi.....

2nd the printhead motor make slower movement so they " divide " each of the guider lines ( not really - really dividing them, but seems to ) according to the resolution ( |||||||||||||| = usual 1200 dpi printing ), ( |x|x|x|x| = 2400dpi, they fire the bullet when the print sensor pass the real guide line and they also fire when the sensors reach the half distance from one line to other ), and so on....

That's also explain why the old BCJ 2100 not have the " Printhead Alignment " function, while your IP1000 have....coz the bjc 2100 doesn't have the guider plastic and pixma does have

i hope you understand it

 

[cd187]

CC, Endmukbud. The light will most likely be an optical encoder, used to verify the position of the printhead location to the printer's drive control circuitry. The drive motor is usually a stepper motor, which requires a series of on-off pulses to create motor movement and the encoder counts the lines on the strip as a control feedback loop (often referred to as "closed loop"). Stepper motors can be run without the encoder feedback (often called "open loop") as the design of the stepper motor will only allow it to "spin" so far for each pulse signal. Several printers in the recent past got by using an open loop drive control circuit. I think the higher resolutions on today's printers, along with the smaller ink drop sizes, dictate the use of a closed loop control circuit. A lot of the encoder and drive control mechanisms used in today's printers were not cost-effective to use just a few years ago. I believe that the cost of encoders and motors has dropped partly as a result of the booming optical disc drive (CD/DVD/DVDwriter) market, whose drive control sytems must be very precise. This has helped allow printer vendors to incorporate this increased technology without a price increase.

As someone who remembers repairing consumer electronic equipment that contained vacuum tubes, years ago, the rate of progress is awe-inspiring. A printer with the Canon IP4000 abilities could not be had at any price just 5 years ago. And you can go and pick one up today for about $100 US! Amazing!! Anyone here remember the Canon BJ-1?? Hehe.

 

[bobglen97]

Anyone here remember the Canon BJ-1?? Hehe.

Good explination of the stepper motor and encoder.

Back in 1984/85 HP marketed a Canon engined bubblejet printer (HP laser printers were all powered by Canon engines) for graphic screen dumps on the 900 series engineering workstations. Only was available with an HPIB interface (16/32 bit proprietary serial cable) for about $2000 (the workstation itself was 16k, and 1 meg memory cards were $1500). This was offered as an upgrade/repacement for the current graphics thermal printer. The cartridge was a smaller version of those little 1/2 & 1/2 containers you get at McDonalds. When placed in the carriage, the print head was closed, puncturing 9 little holes in the foil, enabling it to emulate a 9 pin epson dot matrix printer. Was quite an inovation for the time.

Bob

 

[Endmukbud]

nice..... CD187 Thanks

last night i was dream bout these stepper motor and the mechanism....
N there is one thing i want to know about
These loop rules, count, mechanism. Did it already built in inside the printer CPU, or just in the printer firmware / bios. So what i mean is, if we can open and re-flash the firmware somehow, we could increase the printer resolution and speed.
Voila ........
Cause like the XNU and PIXMA they have precise same electric board ( PCB ) circuits
but different resolution.

 

[cd187]

Hiya Bobglen.
I can remember some of HP's early inkjets printer/plotters. HP and Canon have had a strange relationship regarding printers, as you note with the lasers. Both claim to have invented the inkjet, but surely HP was a prime mover in the early adoption of inkjet technology. Canon contends HP "borrowed" the idea after Canon showed HP reps a demo of the "Bubblejet" technology. Siemens claims to have invented the "drop-on-demand" idea, but never really developed the hardware. The early Canon Bubblejets, BJ-1, etc., and HP printers, had a seperate ink "bladder" that connected to the printhead by a small tube, providing a continuous flow system. The ink bladders held enormous volumes of ink compared to today's ink tanks. Of course, the printer vendors made their money on the price of the machine. A HP Deskjet printer would set you back about $1000US in 1988. So $30US for an ink tank seemed like a bargain.