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© Vincent Oliver 2005

 

 


HP Photosmart 8250 printer

page 1

HP Photosmart 8250 printer review. One of the perks of being a journalist is that we get to see many new products before they become public knowledge. Besides the new Epson R2400 and UltraChrome K3 ink set, there hasn't been much else to grab my attention, well that is not strictly true. HP took a number of technical journalists to Tenerife to show us their new range of printers, cameras, scanners etc. One item that caught my eye was the HP 8250 A4 printer. On the surface this printer looks much like any other printer I have seen, but it's what's under the bonnet is the real news.

HP launches the individual ink cartridges in an A4 printer

So what, Canon and Epson have had separate ink tanks for a number of years and HP also has them in their large format printers, so is this really news? The story is not just the individual ink cartridges, it's the new print head that steals the show.

One of the advantages and maybe disadvantages with HP Photo printers is that you get a new print head every time you replace a cartridge. This adds extra cost to photo printing, but also guarantees that your photographs are going to look great every time. It is often thought that a combined ink cartridge is a wasteful system, you may not have used up all the ink for one of the colours but if another has run out then you have to trash the entire cartridge. Using individual ink cartridges ensures that you only throw out the spent cartridges. But as we all know by now, things are never that simple. Yes, with HP you do have to throw away the cartridge when one of the inks runs out, but generally speaking the colours all tend to run out at the same time.

Now, using separate ink cartridges the same thing happens, when the magenta or other colour runs out, the others tend to follow fairly quickly. The most frustrating part is that when you insert a new cartridge the ink is primed, this is not just a localised priming - all the inks tend to be primed. The net result is that if another colour was running low then the priming process may also render that colour as empty, so you replace that colour and the priming process starts all over again. In my experience this seems to affect two or more colours at a time. Imagine how much ink you have just flushed away.

The other problem is that if air gets into the nozzles then the nozzle is effectively blocked, the only way to get rid of this is to perform a nozzle clean or a deep head clean. This means you are using expensive ink to clean out the nozzles, and where does the ink go? To answer the last question, it is caught by a sponge which sits under the printer, depending on how much you use your printer, this will eventually become over saturated and will need to be replaced. So you can now see that using individual ink cartridges is perhaps not the most efficient method.

HP re-INVENTS the print head

With the introduction of the HP 8250 printerHP have addressed the issues that I have briefly outlined above, The 8250 is a six ink printer which uses separate ink cartridges, but unlike other manufacturers printers, the cartridges are fixed in a static position and the moving print head head is fed by means of a flexible tube.

Chunky ink cartridge just contains 4.5ml of ink
Larger black cartridge contains 17ml
Inks push in over the print tray
Six Vivera inks fitted (black is out of frame)
The Cyan ink cartridge
Detail

 

Individual ink cartridges that do not move with the printhead

The ink cartridges in the new HP Photosmart 3210, 3310 and 8250 are in fixed locations over the paper tray. Fitting the ink cartridges is simple enough especially as there is no chance of error, unless your colour blind, but then you wouldn't be looking for a colour printer. There are several benefits to separating the printhead and ink cartridges:

  • The cartridges are placed in the most convenient location for replacement.
  • The mass of large ink cartridges does not travel back and forth at high speed (a source of vibration in other printers).
  • There are two easily accommodated black cartridge sizes available for use.
  • The printer profile is lowered and the print carriage is more compact.

Of course the disadvantage is that you keep the same printhead for the life of the printer, as with Epson and Canon printers. This means that over time the quality will gradually deteriorate, having said that, by the time you notice a loss in quality the technology will have moved on and you will probably want a new printer anyway.

Each ink cartridge contains a single ink colour. By supplying each colour in individual ink cartridges, HP has eliminated a concern some users have with tri-colour cartridges – that if they print images that require an unusually large amount of a particular colour of ink, a cartridge may require replacement before all the inks in it are exhausted. HP’s new ink cartridges require replacement only when every drop of usable ink is exhausted. Although HP could have been more generous in the amount of ink supplied with each cartridge.

 


This is where this printer starts to become interesting. When a head clean is performed, the ink is still used to clear the nozzles, but the clever part is that the printer catches the ink drops and re-pumps the ink back into the cartridge. There is no ink waste with the 8250. I hope this is a feature we will see incorporated into many more photo printers in the future.

Active air management

In all inkjet printing technologies, air bubbles can form and accumulate in the ink. Air can enter the printhead directly through the nozzles during operation, or when air dissolved in the ink forms bubbles. If they aren’t removed, air bubbles can prevent drop ejection by interfering with the supply of fresh ink. Air bubble obstructions can cause poor print quality and if an air bubble enters a drop generator and the generator is operated without ink, it can be irreparably damaged. Inkjet printers employ either an open or closed-loop process to eliminate air.

Competitors’ open-loop inkjet printers remove air by priming the nozzles. In priming, air and ink is pumped out of the system through the nozzles. Since it is difficult to separate the air from the ink, both are removed from the printhead together and the ink is deposited in the printer service station. The deposited ink, sometimes representing a substantial amount, can no longer be used for printing.

HP’s closed-loop ink delivery system uses active air management to eliminate air without priming. Rather than drawing ink out of the system, the closed-loop process separates the air from the ink so the ink is recovered for printing and the air is safely eliminated. To do this, the pump moves the air and a small amount of ink away from the printhead nozzles and back to the ink cartridges. The ink and air are separated in the vent chamber: the air leaves the system, while the ink is retained for printing. Ink is not wasted in this process and air bubbles are eliminated for great print quality.

 

Component

Features

Benefits


Ink cartridges


HP ink cartridges supply the system with fresh ink in individually replaceable containers. Six cartridges, one for each colour, must be in place for the printer to function. The colours are black, yellow, light cyan, cyan, light magenta and magenta
.


Colours are replaced only when needed.

Pump

The pump works in two directions, moving ink from the replaceable cartridges to the printhead reservoir and removing air from the printhead. The tubes are emptied to reduce evaporation of ink components and deposits of dried ink.

Ink is used more efficiently because air is removed from the system without wasteful priming.

Ink sensor

The ink sensor detects when ink in a cartridge is exhausted.

The message to “Replace Cartridges Soon” gives timely and accurate information – when it appears, there is no more usable ink in the cartridge.

Factory installed printhead

Each factory installed printhead contains 3,900 nozzles on a single piece of silicon and places millions of ultra-small drops per second on the media. The onboard reservoir provides a continuous supply of ink to the printhead. The reservoir has six chambers, one for each colour. Each chamber has an internal regulator to supply ink to the printhead at constant pressure and prevent ink from escaping through the nozzles. Each chamber has a microporous filter to trap particulates before the ink reaches the drop generators.

Precise nozzle alignment and drop volume measurement ensure exceptional photo prints. The onboard reservoir protects the printing system and with genuine HP supplies, ink is still available for printing after a cartridge is exhausted. The printer will not stop in the middle of a page.

Vent chamber

The vent chamber separates the ink from the air removed from the printhead during pumping. The ink is pumped back into the cartridge and the air is purged from the system
.

Air is eliminated from the system and ink is retained for printing.

Ink supply station

The ink supply station provides simple cues for correct cartridge insertions. The cues include colours and icons that match proper cartridges and mechanical features that exclude cartridges of the wrong colour.

Easy front access and simple cues make cartridge changes effortless.

 

 

14 January, 2006

© Vincent Oliver 2008 www.photo-i.co.uk
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