January 15, 2018

The HP Laserjet 4

These are very solid and durable printers. I have read that some have printed in excess of 1 million pages. They sold for $2200 in 1992 when they were introduced. They allow "straight paper feed", which allows very thick paper to be fed by using the manual feed and exit at the back of the printer.

There are two major variants.

The 4L and 4P (and 4ML, 4MP) are inexpensive versions that use the Canon PX laser engine, and are less desirable. These use the 74A (92274A) toner cartridge.

The other major variant uses the Canon EX print engine, which is very robust and delivers 600 dpi. These use the 98A (92298A) or 98X toner cartridge. I have 3 machines, a 4, 4+, and 4M+. These all use the EX engine and the 98A cartridge.

The "M" versions also have a local talk interface, but I never cared about that, they also have postscript, which is nice. They were targetted to work well with the Apple Macintosh, hence the "M" designation. Unix users like them too.

They can have memory upgrades done and postscript modules added, making any given printer a possible hybrid. Memory to upgrade these is very cheap these days.

Toner cartidges

More on this below. It is important to know that the toner cartridge is much more than just a box with toner. It contains vital moving parts of the printer, in particular the all important drum.

The cartridge includes a "wiper" that is made of rubber or some plastic with similar qualities. As you might expect this can age and get hard and fail to do its job.

Note that you must remove the drum from the cartridge if you intend to clean it with any kind of liquid (isopropyl on a tissue). I have never actually done this and don't know how hard or easy it might be.

Engine Test Button

You open the manual feed panel on the front and find an almost invisible hole inside on the right. A paper clip inserted in this hole will trigger a "15 Engine Test", which should produce a sheet of paper with parallel lines spaced about 3mm apart. I would be reluctant to buy a used printer that didn't do this.

Control Panel

You get 8 buttons, a ready light, and a 16 character display. The upper 4 buttons do as labeled (online, form-feed, paper-size, enter). The lower 4 button can be modified by shift to perform an alternate function (shift, menu/reset, item/continue, +/-).

Use Menu to cycle through the menu choices. Once you see a submenu you like, use item to cycle through the submenu choices. Use enter once you see what you like. For example:

I would do this on any used printer I was considering buying.

You can discover if a printer has postscript installed by examining the entries in the test menu. If postscript is present, you will be offered "PS CONFIG PAGE", "PS TYPEFACE LIST", and "PS DEMO PAGE".

Service Mode and Page Count

Laserjet 4 printers (except the 4L and 4P) keep count of how many pages they have printed. You can access this count on the display by entering "Service Mode".

To get into service mode, do this:

  1. Turn the printer off.
  2. Hold down 3 buttons: online, formfeed, and enter.
  3. Turn the printer on.
  4. Continue to hold the buttons down till online and formfeed are both lit.
  5. Release the buttons.
  6. Press formfeed.
  7. Press enter.
  8. The display will show "Service Mode", then go to "Self Test", then return to "Service Mode".
Once you are in service mode, you can view the page count as follows:
  1. Press Menu to get the Service Menu.
  2. Press Enter till you see the page count.
The printer I just got my hands on shows 157,700 pages, wow!

Troubleshooting

Jet Direct Card

So, after buying my printer, I nosed around on Ebay and found someone selling a Jet Direct card for about $20. I selected one that had only a 10baseT connector - I didn't want AppleTalk or a 10base2 BNC connector or any of that. It is trivial to remove one screw and a small panel and plug this thing in. After doing this, a new menu entry will appear after the "Serial" menu which is called MIO Menu - you use this to configure the network interface.

You get to this menu by taking the printer offline by pressing the online/offline button. Then you repeatedly press the menu button till you see "MIO Menu". Then you press the "item" button to enter this menu and run through the options. It will offer you one option: "CFG Network = NO". To utilize this, you press the "+" key to change NO to YES and then press "Enter" to make it so. You always, every time you change or modify anything in the HP menu system, hit enter to make it so. A common error is to make a change, not hit enter, and then wonder why your change did not "take".

After electing to configure the network, pressing the "item" button will run through things you can modify (screw with). I wanted Novell off, Etalk, off, and TCP/IP on. Then the key thing is when you see "CFG TCP/IP=NO, use + and enter to make this yes, and you will be able to set the IP number and such. I turned BOOTP off, perhaps this would use DHCP, but I was not into doing this - I want to static configure this printer. You get to set the IP address a byte at a time. Use + to increase the value and shift + to decrease it. This is somewhat painful, so be sure to hit enter when you get the value you want, or you will have to do it all over again. SM stands for subnet mask (which I set to 255.255.255.0).

GW stands for gateway, which I did not and do not want to set (I left it at 192.0.0.192 as it was shipped to me). LG stands for Log Server, which I left at 0.0.0.0 (I don't think I ever want to set this up, and would have to figure out how to set up a server to log whatever the printer might want to log, and this is more than I am interested in right now, and probably ever).

I am told that you can telnet to the printer once all this has been set up, and that interface may be a lot more convenient for additional configuration. I am told that the telnet interface has a nice help menu.

There was also a protocol labelled LLC/DLC that I should have turned off. LLC/DLC is HP's proprietary Logical Link Control/Data Link Control protocol.

It is possible (and I do it all the time) to print postscript via the following one line script which just sends the stuff to TCP port 9100: 

nc printer 9100 < file.ps

Toner

The savvy buyer of a laser printer (or any printer) carefully considers the price and capacity of consumables, in this case how much a toner cartridge costs and how many pages it can be expected to print.

The printer I have "in hand" has an HP 92298A cartridge aka "98A" and I see compatible cartridges selling for $35 or even less, which is quite good. HP claims 6800 pages from a cartridge given 5 percent coverage, darn good.

Genuine HP 98A cartridges cost on the order of $85 or more. You can buy a premium remanufactured HP 98A on Amazon for $49.

The 98X is a "high yield" version of the 98A. Either will work in a printer with the Canon EX engine. (like my Laserjet 4M+)

So you get an extra 2000 pages with the 98X. This is hardly an issue for me, since I probably won't print even 1000 pages in my life. So I can pick either one, perhaps selecting the best price. What is a concern to me is quality, in particular the condition of the rubber parts like the wiper. I expect the parts to break down before the toner runs out.

The genuine 92298X was discontinued by HP in November of 2009.

Parts

Lots of parts for these are available: service kits, roller kits, maintenance kits, even entire rebuilt printers for the price of a service kit on Ebay.
Some sources:

More info and manuals

The Maintenance Manual is excellent. I have not found a "user manual" online, but the maintenance manual covers everything you would want from a user manual, so this situation is just fine actually.

Have any comments? Questions? Drop me a line!