Canon or Epson for photocopying? Need some help picking one.

[panos]

I would go for an Epson using pigments on all colors because they are superior for purposes such as photocopying (water resistant & highlighter friendly).

Eg. http://www.epson.com/cgi-bin/Store/jsp/Product.do?BV_UseBVCookie=yes&sku=C11CB86201

 

[Tin Ho]

I just printed some IRS tax forms. I timed my mp830 printing. It took 7 seconds to print the first page and 9 for the 2nd. Both pages are full of text. If these were printed by my new R2880 ir would have taken a minute for each page. The difference is huge in printing text documents. My mp830 will print a 8x10 photo in high quality mode in less than 3 minutes. The r2880 typically would take 7 -8 minutes.

If you print a lot of text documents forget about Epson printers. If you print photos and need 100 years of fade resistance use Epson but not models with dye inks.

Speed does not kill Canon print heads. Bad ink and bad cartridges do. It has nothing to do with speed. If you use clogged cartridges in your Canon printer slow printing will still kill the print head. If you want the speed of printing Canon printers are the choice.

 

[turbguy]

From HP:

Thermal Cycling and Mechanical Cavitation
The thin-film heater resistors used in the integrated driver
printhead are subjected to severe mechanical stresses during operation. These stresses arise from thermal cycling of
the resistors and cavitation forces as the vapor bubbles collapse on various surfaces within the firing chambers. The
thin-film resistor material is heated from near ambient temperature to well above the superheat temperature of water
(the principal solvent in HP thermal inkjet inks) within several microseconds by each firing pulse. This results in large
cyclic temperature gradients within the thin-film stack, in both the vertical and lateral directions. Thermal cycling to
this extent creates extremely large mechanical stresses and therefore imposes a number of constraints on the thin-film
materials used. In addition to chemical compatibility and thermal stability, the films above and below the resistor film
must have stable, well-matched, film stresses to prevent cracking or delamination during operation.

During the cooling phase of each drop ejection cycle, the drive bubble collapses, allowing refill of the firing chamber
with ink. While seemingly benign, the bubble collapse can create a microjet of fluid which causes large localized pressures on the surface it impacts. This process, known as cavitation, is difficult to observe directly, but it does produce pressures in excess of 130 atmospheres. If the firing chamber is incorrectly configured, these cavitation events can
peen the protective films over the resistor and actually chip away portions of the film. Once damaged, the nucleation of
subsequent bubbles is altered. If severe enough, this damage initiates a chain of events that can cause the resistor to
break open and fail.

More at http://www.hpl.hp.com/hpjournal/94feb/feb94a6.pdf

These mechanical stresses, which are unique to thermal inkjet technology, impose constraints on the integrated circuit chip in the integrated driver printhead, since the drive
transistors share several films with the thermal inkjet portion of the device.


ALSO from other sources...

"The failures presented in this work showed three primary factors influencing the failure modes and lifetime of printhead; bubble cavitation damage, thermal fatigue, and electromigration of heater".

 

[Tin Ho]

ALSO from other sources...

"The failures presented in this work showed three primary factors influencing the failure modes and lifetime of printhead; bubble cavitation damage, thermal fatigue, and electromigration of heater".

Turbguy, thanks for pulling the amazing text regarding HP's thermo bubble jet technology. There is no doubt about the severity of stress of thermo bubble jet print heads in operation. This reminds me the engines of modern automobiles. They are made with tremendous precision and technology marvelous today. however, still it is a common knowledge that those engines tend to be killed indeed by speed. If you over rev them frequently they may die suddenly in fact. Think of the timing belt. When it breaks loose by over revving that's when the engine gets killed.

The thermo bubble jet print heads are actually not quite the same. You can't over rev them. Its speed is predetermined by the manufacturer. It's not like you can over clock it to cause it to fail prematurely. Despite the severity of stress inside the nozzles of such print heads they are designed to withstand it under normal operating conditions. Such conditions include correct ink flows from the ink cartridges and use correctly formulated ink. If these conditions are not met the print head will get killed regardless they are speeding or not. It is not the speed (that they are operating at) that kills them. It is the operating condition not meeting the requirement that kills them.

The three primarily factors influencing the failure mode in the text you posted does not include anything about speed. Well, live is killed by speed too. Imagine if time is sped up 100 times we would all perish within one year of time.

Besides, you can't slow down your Canon printers, can you? Once you start a print job it is going to go at its own speed. You can't slow it down a little trying to extend its lifespan.

 

[turbguy]

My Canon's have a "quite" mode that slows printing about 25%. Other than selecting this mode, you are correct, I can't slow down the printer. Nor can I "overclock" it. I believe the OEM's do that in the marketing race to produce a faster printer. As long as they can get the majority of production to survive the warranty period, marketing wins. After all, who determined the pricing of OEM carts? Printer marketers didn't have to follow the "razor blade" model for ink carts, YET THEY CHOSE TO!

And also, you are correct, thermal fatigue in engineering is typically measured by counting "cycles" (ie, nozzle firings), with no time dependency.

HOWEVER, in microelectronics and even recently in superalloys, it has been shown that frequency of the cycles does indeed ACCELERATE the damage (less cycles to failure):

"The effect of loading frequency and microstructure on thermal fatigue damage in 200 and 300 nm thick polycrystalline sputtered Cu lines on Si substrates has been investigated. Alternating currents were used to generate temperature cycles (with ranges from 100 to 300 degrees C) and thermal strains (with ranges from 0.14% to 0.42%) in the Cu lines at frequencies of 0.2 and 20 kHz. Fatigue loading caused the development of severe surface roughness that was localized within individual grains. Raising the loading frequency accelerated damage formation and failure. The frequency effect is believed to result from differences in the concentration of defects created by the deformation-induced motion of dislocations to the grain boundaries".