Customers annoyed that I am fixing their copier?

I just had a job to do a periodic black drum replacement on a Bizhub C552. This was an automated call so the customer did not call us but should have known we were coming because there was a message on the copiers screen. Replacing the drum hardware only takes less than 5 minutes and then I would need another 5 minutes to perform gradations and stabilisation adjustments. 

Before I could finish replacing the drum I had a guy looking over my shoulder to see where his printing was. Since I don't turn the machine off while doing this procedure the print job was in the queue so I quickly shut the machine to allow his print job to complete while replacing the filters in the back of the machine.

Since there are no more jobs in the queue I switched to service mode to do the calibrations. The gradation adjustments involve printing a pattern of gradation bars and placing the print on the scanner to allow the mc to analyse them. The first page worked fine but the second failed. I started the sequence again but while printing a girl came over and grabbed the gradation sheet from the output tray thinking it was her print job. She took one look at the coloured bars on the page, gave an annoyed grunt and then asked if the printer was working. 

She had to walk around me, a stranger to this office, step over my open tool bag but only thought to ask if the machine was working after she had grabbed my printing? Clearly not the brightest and unfortunately not the only unobservant person in this office. During the following problems I stopped what I was doing several times to allow printing but was constantly getting questions about when the machine can be used by annoyed looking staff. My reply was, as always, to smile and say that they can print but may need to wait a minute to collect their jobs. The responses were universally grunts or moans.

The problem I had was that I was printing the gradation patterns on A4 paper and the copier was not accepting the first pattern but gave no explanation. The pattern looked ok to me so I first cleaned the scanner optics (pausing for print jobs) and tried again but failed. So I next cleaned the IDC sensors, performed initialisation and stabilisation and tried again but still failed. So while pausing again for any print jobs I had a look at the gradation prints and noticed that the patterns were evenly centred on the pages. Normally they are closer to the bottom of the page. Hmmmm.

The machine normally takes its paper from trays 1 and 2 for gradation prints so I pulled them out as well as tray 3 which had pre-printed letterhead loaded in it and tried again. I wanted one of the lower trays as they are large capacity trays that are only for A4 and therefore have their guides fixed to the machine and so there will be less centring issues. Sure enough the gradations worked.

So the problem was with either tray 1 or tray 2 not being centred. These trays can hold several sizes of paper by having their guides opened or narrowed to suit. The guides can also be moved forward and back in the machine to adjust the centring of the paper by loosening two screws and then adjusting them. A notch on the metal base plate lines up with a scale on the plastic tray to give an indication of where the centring currently is. On this machine both trays were currently pushed all the way to the rear off the scale. Gouge marks in the plastic around the fastening screws showed that the guides had been forced to the back without loosening the screws so my guess is that someone had tried to open the guides without releasing them first and this caused the centring to change.

Easily fixed.

While not being able to complete the gradations or the centring problem with trays 1 and 2 were not critical problems and probably not noticeable to most of the people on this office it would have been nice to fix them without all the negative comments and noises. I am just trying to help.