Paul

asked Dec 28, 2001 at 6:27pm
Apple Apple StyleWriter II

Left half of Page is Blank

Here is a stumper:

We have an Apple LaserWriter II NTX (Canon SX Engine) wich only prints on the right side of the paper.

The left 3-3/8" side of the page is totally blank. There is about a 1/4" fuzzy zone and then the right side prints fine.

Simular result whether PostScript startup page or test page by pusing test button on bottom of unit under access cover (Formatter Test???). Printing on the right side. Left side blank.

Tried known good toner cartridge. Cleaned transfer corona wire. Opened the shutter and cleaned the mirror over the toner cartridge.

It still didn't work. I removed and looked at the Laser/Scanner Assembly (above the paper tray). From the outside, I could see nothing wrong, but I did not open it as it does not apear to be designed to be opened.

Any ideas?
Even more info.

I tried swaping both the Laser/Scanner Assembly (a pain) and the DC Power Supply. No noticeable change was my reward!

If I change the print density knob on the top of the high voltage Assembly, it can increase the width of the printable area. But no setting will cause the entire page to print.

This would imply it might be related to the high voltage, but if that is so, why just one side? and why the right side, which is further from the HV than is the left?

I am still puzzled and looking for help. Any ideas on what is going on here?
by Paul on Dec 28, 2001 at 8:13pm Add comment
You can do what is called a "half test".

Give a print command with a page with a good deal of text. When the page is half way through the printer, switch the printer off.
Remove the cartridge and open the cartrige door. Is there toner on the LH side of the drum?
If yes, you have a transfer problem. Look at the transfer corona.
If no, you have a laser problem. The laser door may not open properly.

Hope this helps.
by unknown on Dec 29, 2001 at 4:40am Add comment
Great test idea, but the results are strange.

When I shut off the printer with a sheet half printed and look at the toner cartridge I see what we would expect on the right side of the drum, but the left side of the drum has only a dusting of toner. However, (this is the weird part) the image is clearly visible in the dusting.

Oddly, it is a reverse(negative) image. There is no toner at all on the places where the image is.

I would think the fact that I can see an image (even a negative) would indicate the the laser is working properly. (I changed images, just to make sure it wasn't some kind of artifact.)

However, it would seem the tranfer corona isn't implicated because the toner is not properly deposited on the drum to transfer.

What am I missing here?
by Paul on Dec 29, 2001 at 7:12am Add comment
Pull the toner cartridge out and check the instruction label above the mirror assembly. The labels have a nasty habit of coming loose and blocking the light to the cartridge. When you open the door, they fall back into place. If it's loose, just glue it back or rip the whole thing off.
by moe on Dec 29, 2001 at 6:01pm Add comment
Thanks for your continued help, I think I am getting close.

Could a bad bulb from the Pre-Cond Exposure Lamp Assembly cause this problem?

Thinking it must some how be related to the high voltage, I swaped both the High Voltage Assembly and the tranfer corona with know good units. No change.

So, I decided to swap the upper body (at the hinge and above) with a known good one. That fixed it, so I now suspect something is wrong with the upper body. I took the suspect one totally apart, found nothing wrong. Everything looked fine.

I put it back together, put it on the printer and it still didn't work. I took it completely appart again, but this time when I tested the lamp assembly with my ohm meter it was open. I looked through all of them, it turned out one of them was bad.

However, the one that was bad, would have been at the right end of the assembly and it was the left side of the paper that was blank.

Are we getting close or is this printer from some Hollywood set (Poltergeist, Exercest, etc.)?

By the way, do you sell replacement bulbs?
by Paul on Dec 29, 2001 at 9:30pm Add comment
Those are actually erase lamps. They serve to erase the residual charge on the drum unit to prepare it for the next cycle. Your problem is with the mirror unit. Could be some loose parts or the aforementioned label.
by moe on Dec 30, 2001 at 10:44am Add comment
So what was the cause of the problem?? I am getting the exact same issue...
by unknown on May 3, 2005 at 2:05pm Add comment