HP Deskjet 940C Problems

[Old Sparky]

I guess this still qualifies as 'modern' ?  What has happened to this machine, which, for a long while printed perfectly acceptable black & white diagrams, documents, etc., but had a colour fault in that the blue element was missing, even with a brand new cartridge fitted, is that, since yesyterday morning, it only prints very faintly, despite cleaning the contacts in the cartridge holders, and trying several different cartridges of various makes.  It was a case of 'today acceptable monochrome quality, tomorrow useless'  Maybe I should dump the 940, and get a new printer, but, before doing that, is there any way to rectify the above faults?

[Nick]

Probably a blocked jet. You are, of course, using *real* HP cartridges

On windows, assuming you're using the correct driver,

1. Click Start , Programs , HP Deskjet 900c series , and HP Deskjet 900c series Toolbox .
   
   
2. On the Printer Services tab, click Clean the Print Cartridges . The Clean Print Cartridges dialog box appears.
   
   
3. Click Clean .
   
   
4. A page prints that shows the results of the first cleaning. If the print quality is good, click Done. Click Intermediate Clean to do a more thorough cleaning and continue to the next step.
   
   
5. Another page prints that shows the results of the intermediate cleaning. If the print quality is good, click Done . Click Prime , to prime the print cartridges and continue to the next step.
   
   
6. A third page prints that will show the results of the priming. If the print quality is good, clickDone . Click Clean Again to clean the print cartridges again. If the print cartridges are not clean after this last test, they may be faulty and need to be replaced.
   

See: http://support.hp.com/us-en/document/bpd06920

[tiv48]

I had a hp printer for years and it gave sterling service but the cost of the ink was horrendous.
since then a have gone through a collection of Epson and cannon ink jets all have given good results but once the fixed heads blocked (from infrequent use ?) that was it repairable.
last year I made the decision to get a laser printer.
the main reason was most of the stuff I was printing was black & white in large quantity's but not very often.
the one I got cost £104 it is wireless and colour the supplied toners printed over 500 pages and a set of pattern toners cost just over £20 and will print over 1000 pages
it will print good colour on ordinary paper and print on film.
I don't think I would ever go back to an ink jet.
Rob T

[Mark Hennessy]

Yes, I was going to say similar things.

Unfortunately, inkjet printers are "consumable", given the retail price. As we know, they are essentially sold as loss-leaders, the loss recouped in ink sales. That said, I paid £200 for a Canon printer/scanner about 10 years ago, and it's been the best inkjet printer we've ever had by a country mile. It's printed hundreds of 4 by 6 photos at much better quality than the high-street shops could manage, and text is always sharp and crisp - almost as good as laser, and almost as quick. Never had a blocked nozzle, despite several periods of non-usage lasting many months. The print head is replaceable, but no idea how much they cost if needed. No idea if a new Canon would be as good for so many years...

But we use a laser printer for the bulk of our printing. New ones are astonishingly cheap, and are fast and energy-efficient (old laser printers can be quite "thirsty", especially if it's one that keeps the fuser hot all the time they're powered - early HP LaserJet 4s, for example). You get thousands of pages per toner cartridge. As a new cartridge contains quite a lot of moving parts, they are fairly pricey, but you can refill most cartridges or get cheaper "rebuilt" ones which are usually OK (if bought from somewhere like Cartridge World, you can always return them if there is a problem).

Second-hand laser printers are surprisingly cheap, and usually have plenty of life left in them. LaserJet 4s are about 20 years old, and yet they still keep on working (quite a lot of the innards of many HP printers are supplied by Canon). I've got a HP LJ1200 at home - a basic unit, but has been very good over the years. I intercepted it on its way to the skip about 8 years ago, and now the cartridge has finally run out I'm trying to decide if I should buy a new cartridge or just another second-hand printer from eBay.

So if you have the space, consider having both a laser printer and an injet for the occasional colour jobs...

(But while inkjet has traditionally had the edge in quality terms for printing photographs, colour laser printers are feasible replacements for injets today - the quality can be very impressive indeed)

Apologies if you already have a laser - in which case I'm preaching to the converted

[Nick]

I threw away our last injet many years ago - I have either bought second-hand HP printers (invariably good) or what I currently have at home, a year-old Lexmark X543dn, which cost under 60 quid with at least 1000 pages left in its cartridges - it also has a scanner (e.g. to PDF then emailed), does duplex (double-sided) printing, booklet printing and has a 100Mb/s ethernet connection.

Lovely machine. Without the scanner, its called a C540dn - also a great machine (have one of those in my workshop)

However, with lasers there are 4 colour cartridges which can also cost real money - Black, Magenta, Cyan & Yellow - typically 40 quid each.

As ever - the printer is cheap, the consumables cost. However, there is less to go wrong with a laser printer, but their photo printing is not as good as an inkjet.

There's an X543dn new, without box or cartridges, for 99p on eBay as I type - http://www.ebay.co.uk/itm/Lexmark-C543DN...1860304280

[Alan Douglas]

I started with secondhand Laserjet IIs, then IIIs, IVs, and something that calls itself a 1320tn now. When I was working I could use the office color laser but you know, in the year and a half I've been retired, I haven't needed to print a single color page. So for the present, b&w is good enough.

[Mark Hennessy]

One amusing thing about laser printers - if you leave one in a cellar, the paper will obviously absorb moisture. When you print, as soon as the paper hits the fuser unit, clouds of steam will billow out!

Surprisingly, this didn't seem to affect print quality. However, the printer was hastily moved upstairs! Since then, the cellar has become a lot drier, but I haven't risked leaving a printer down there (if nothing else, it's a bit dusty as well). Thank goodness for network printing

[Old Sparky]

Two things, or maybe 3, in response. 1) I can print pages from this forum in good quality monochrome, but not some diagrams downloade from UKVRRR. 2) For some reason I couldn't find the 900 series printer by following the links you provided, Nick, only the HP3900 series, which I still have installed (Might have to go back to that printer!), and 3) I might consider getting a laser printer. A neighbour advised me to do that some time ago, but I guess I'm reluctant to scrap something if it can be kept working!

[Mark Hennessy]

Hi,

Often, diagrams will print in much worse quality than diagrams. In simple terms, when text is sent to a printer, it is sent at a very high resolution - perhaps 300 or 600 or even 1200 dots per inch. So even with a magnifying glass, the print will look clear and detailed.

Now, a screen has a much lower resolution - perhaps 72 dots per inch (it depends on screen size and resolution - this monitor has 1920 pixels across, and measures just under 20.5 inches, so that's about 93 dpi. It's probably 96dpi "officially").

Having looked at those numbers, you might see why something that looks good on the screen might not look so good on paper. A scanned in diagram that has been reduced in resolution to look acceptable on the screen will generally look a bit fuzzy on paper.

It gets a bit worse when you consider how printers make shades of grey. The ink (or toner) is black. So the only way to make grey is to print a pattern of black dots and leave white space around them. From a distance, the eye merges these dots and sees grey. The exact shade depends on the ratio of black dots to white paper. This effect used to be very obvious on old newspaper print from 30+ years back...

There is a good Wikipedia article about this process: http://en.wikipedia.org/wiki/Halftone

A high resolution printer than can print at 1000dpi will deploy this technique very effectively when given a high quality image as its starting point. Older printers that could only print at 300dpi gave reasonable results, but looking closely, one could usually see the dot patterns that made up the shades of grey.

Of course, this also applies to colour printing, where the half-toning is done with the 3 primaries as well as the black ink or toner.

All very interesting - perhaps! - but doesn't answer the question. In short, you've probably got the message about laser printers by now, but what to do about the HP? How much effort it deserves might depend on how much ink you've got left to play with

One thing that occurred to me earlier:

The advice in post #2 is good, but the initial steps might not be correct if you haven't installed the whole suite of HP software. You should be able to find the options to clean the print heads and print test pages from the print driver alone - and the print driver is the bare minimum needed to make it work - so the following should help:

On Windows 7:

Click Start, move across and click on "Devices and Printers"

A box appears which should show your printer. Right-click on it, and select "Printing Preferences"

Up pops another box which will have many different options, and the exact options will depend on the printer driver that Windows is using - therefore I can't be specific at this stage. But hunt around, and hopefully you'll find options to clean the print heads and more. Looking at the Canon printer I have here, I see a tab called "Maintenance", which offers all sorts of interesting options to play with.

It's interesting that the contents of the "Printing Preferences" box has come from the manufacturer, even though I've never attempted to install any Canon stuff on this machine - Microsoft has obtained the driver from Canon, made sure it is compatible with Windows 7, and then made it available as a driver that gets automatically installed when the printer is first connected. Same deal for my HP laser printer. So I'm sure that you'll have something similar, even if you haven't installed the HP "Toolbox" that Nick had in mind earlier.

Hope that helps,

Mark

[Old Sparky]

Basically, I follow what you're saying, Mark, but, until a couple of days ago, the 940 would print such things as circuit diagrams perfectly clearly & legibly, until I tried to print one by clicking on a thumbnail in a post, which produced several pages of a manual, then, by further clicking on the wanted page, this appeared 'full size'. However, when I tried to print it, the result was almost illegible, and further attempts at printing that diagram, or others, were little, if any, better, including one I have stored in 'my documents', which I've always been able to print perfectly before.