HP LaserJet 400 M401 PCL 6 Duplex problex

[Mark090]

The HP 400 continues to print two-sided using the HP 400 driver.  Yes we can stop it by changing to the PS driver HOWEVER, it reverts back every time WIndows automatically updates.  Is HP EVER going to fix the bug?

[dansdaduk]

I'm not entirely sure what problem you are describing.

What I think you might be claiming is that all print jobs (at least, those using the PCL6 driver) are printing in duplex mode, even when the user specifies simplex in the Print dialogue.

If so, then the following may be relevant.

I understand that some (Windows) printer drivers:

• Include the requisite 'set duplex' control sequence in the generated print job when the user selects duplex for a print;
• Do not include the requisite 'set simplex' control sequence in the generated print job when the user selects simplex for a print;
• Hence the 'simplex' jobs do not override the printer's own default simplex or duplex setting; if this default is set to duplex, the job will print on both sides.

What you should be able to do is change the printer's default from duplex to simplex.

Easiest way to do this will probably be via the Embedded Web Server interface: on the System tab, select the Paper Setup page, and change the Duplex setting from On to Off.

[Mark090]

Nothing is set to Duplex. This was indentified as a bug in the Windows driver a long, long time ago. So far nothing has been done to fix it. The only "fix" offered was to downgraded to the PS driver.  And now, whenever Windows 10 automatically updates everything, it updates the HP driver to the PCL driver and the problem is there again.

[dansdaduk]

When you state "Nothing is set to Duplex", are you referring to settings on the PC, or on the printer itself?

The latter is what I was referring to; if you don't have a network model, you can (I think) only use the EWS via the HP Toolbox, or use the front panel menu system to check/change the configuration. 

What does a Configuration Report (initiated from the printer) show for Duplex ("On" or "Off"?) in the Paper Settings section of the report?

I don't have access to a M401 model, but I assume that the report will be similar to that available with other LaserJet Pro 400 Mnnn models.

... and the workaround that I outlined in my earlier response has certainly worked with some of these other Mnnn  models.

As regards "bugs " and "fixes", can you provide lnks to these? 

[Mark090]

We use it on a network. The computer setup has nothing set to duplex. It prints duplex anyways. This is a KNOWN bug in the driver. Is it ever going to be fixed?

As for links to others having the bug...there are several on this board alone looking for solution.

[dansdaduk]

>> ... The computer setup has nothing set to duplex. It prints duplex anyways. This is a KNOWN bug in the driver

I'm not disagreeing with this at all.

My first reply on this thread states that I think there is a driver bug, and outlines what I think is the "essence" of that bug.

>> ... Is it ever going to be fixed?

I can't answer this.

Like most contributors to these forums, I'm a volunteer - I don't (and have never) worked for either HP or Microsoft.

As such, I have very little influence on how/when/if either of these companies fixes any bugs in their software. 

>> ... We use it on a network.

Therefore you should be able to access the Embedded Web Server on the printer - just point your browser at the IP-address of the printer.

Using this (and as I outlined in a workaround in my initial reply), you may find that you can change the printer's own underlying duplex default to Off -  this will then provide the required default situation for those simplex print jobs which (due to driver bugs) don't contain an explicit 'set simplex' command.

I don't know for certain that this is an option on your printer, as I don't have access to a LJ M401 printer.

But I know that the workaround works with some other models in the LaserJet 400 Pro M4nnn range.

>> ... links to others having the bug...there are several on this board alone looking for solution

... and here is a link to one of those threads (admittedly for a LJ M476, rather than M401) which comfirms that the EWS  workaround works.

http://h30434.www3.hp.com/t5/LaserJet-Printing/MFP-M476dw-Always-Prints-Duplex-in-MS-Word-2010/m-p/5...

[Mark090]

Not this one.

HP 400 duplexing on its own

As for changing it on the printer itself, then nobody would be able to print duplex when they wanted unless they go through and turn it on, turn it off, turn it on, turn it off.  The rest of the computers are MACs and they do not have that problem.  Why can't the driver itself for Windows just be fixed so it will print duplex only when I want it to? Is HP okay with a buggy driver that performs unsatisfactorily?

I know you are not an HP employee.  I hope they monitor these forums and maybe someone in the know can answer that question.

[dansdaduk]

>> ... Not this one ... HP 400 duplexing on its own ...

The final response in the thread that you referenced claims to have found a solution:

"... I solved it by acessing the printer trough hppt ( ip ) and changed on "SYSTEM->PAPER->DUPLEX" to off ..."

I think that this is just another way of referring to use of the Embedded Web Server, accessible by pointing your browser at the IP-address of the printer, then (via this) changing the printer's own default Duplex action to Off, as I described in my initial response.

>> ... As for changing it on the printer itself, then nobody would be able to print duplex when they wanted unless they go through and turn it on, turn it off, turn it on, turn it off ...

As I understand the bug , this would not be the case.

The instances of the bug that I've seen shows that it affects only Simplex jobs - the driver generates jobs which do not include 'set simplex' sequences; hence the outcome is to use whatever is set as the default on the printer (duplex = On or Off, as appropriate).

But with Duplex jobs, the driver does include the appropriate 'set duplex' sequences (and the associated 'set binding' sequences), and these over-ride whatever is set as default on the printer itself. 

[Mark090]

But if I DO want to print duplex by choice, I have to go through all that again?  And, according to that thread, the only actual solution that worked was to use a lesser driver.

[dansdaduk]

>> ... But if I DO want to print duplex by choice, I have to go through all that again?

No.

As I (attempted to) explain, the setting in the printer is a DEFAULT.

So, if the default setting in the printer is changed to Duplex = Off:

• The bug in the driver means that there will be nothing in the print job to set simplex, but this doesn't matter, since simplex is the printer default.

• The bug does not affect duplex jobs, so such jobs will contain 'instructions' to set duplex mode, and these instructions will OVER-RIDE the printer default.

Why not just try changing the setting (assuming that you can via the EWS - we haven't established this for sure yet, although evidence from elsewhere suggests that it can be done), then send some simplex and duplex test print jobs to the printer to see the effect?

I reckon that you could do this in few minutes (and easily reverse it if you don't think it works), yet you've already spent nearly 10 days discussing it.

>> ...  And, according to that thread, the only actual solution that worked was to use a lesser driver ...

There is only one response which is MARKED as a solution (I think that this is a restriction with the software underlying these forums), but this responder claims another solution:

"Hi, I used to have the exact same problem I solved it by acessing the printer trough hppt ( ip ) and changed on "SYSTEM->PAPER->DUPLEX" to off"  

which I interpret as meaning that after he changed the printers default Duplex setting, via the EWS, the problem was resolved (i.e. he had a viable workaround to the (HP or Microsoft?) driver bug).