C-2255 after IU replacememt

I had a slight problem after changing the colour imaging units (IU) in a Bizhub C754e. The 3 IU had reached the end of their lives so I pulled them out and put a new set in. The machine then displayed that an internal error had occurred and rebooted itself twice. Still failing the machine displayed a C-2255 error and gave up. I pulled up my list of trouble codes for these machines on my phone and had a look but this code was not on this list!

Don't panic yet.

I have a list of trouble codes for the C364e on my phone as well and the code is there. Developing unit motor failing to turn. Obviously one of the new imaging units had a problem with its developing unit that was causing the drive to lock up. Not the first time I had seen this so still no need to panic.

I started from the left and pulled the yellow IU and used my pliers to give the developing drive coupling a turn clockwise on the back of the IU. It was jammed.

Sometimes the developing powder in the unit can settle in transport and jam the augers inside the unit. Giving the unit a few taps on the side while turning the coupling quickly freed it up and I stuck the unit back in. I pulled the other two out but they felt ok and went straight back into the machine. I then went through the gradation adjustments without any more problems.

I will point out though that if you have this problem you need to be careful not to shake up or spill any developer out of the new unit as you will not be able to use it and it will need to be replaced. Also be careful not to turn the coupling to hard or it can break. But don't worry if you do as you have a spare on the old imaging unit that you just took out. And always turn the dev unit drive in the correct direction.

Also someone had played around with the date on this copier so now it shows the image unit life counter start dates as being in 2012. Not a problem but may confuse the next tech who comes to look at it and will wonder why the image units were changed 3 years before the machine was even manufactured.

Tray 3 horizontal transport jams

I have a Bizhub C654e with jamming in the tray 3 horizontal transport unit (J-1730). 

The C654e and C754e or their black and white counterparts have large capacity trays for the bottom two trays. Tray 3 can hold 1500 sheets of 80gsm and tray 4 1000. The trays are position side by side with tray 3 on the left so to get paper from tray 3 to the vertical feed path on the right of the machine a hozontal transport unit is fitted above tray 4. This is why tray 4 is smaller.

J-1730 jams in this horizontal transport unit are just the same as jams at the vertical feed and mean that while paper pick-up was good there was a problem with the paper feed or separation rollers. So first thing is to change the worn looking feed and separation rollers. Easy.

Still jamming.

When removing the jammed paper I can see that the paper has not yet entered the horizontal transport unit so the problem must be in the feed station. There are a set of horizontal feed rollers in the feed station itself so I pull the cover off to have a look but didn't find anything suspicious. While the cover was off I removed the feed sensor actuator to have a look to see if the sensor was dusty. This is what I found:

If you look at the face of the actuator you can see a groove cut into it at about the same height that the paper would hit it. 

I had a look at the paper that had jammed and could see marks on the edge at the position of the sensor. Next I manually feed paper into the sensor to see if it would catch on the groove. Yes it does.

It seems that paper hitting the actuator at the exact same spot 200 thousand odd times had worn a groove that was causing the jams. Strange that I had not seen this before. But I had never looked for this before either. I will now.

I sanded and polished the face of the actuator and ran some paper through the machine from tray 3 and could no longer get it to jam so I will definitely need to remember this.

Jamming at the horizontal transport unit exit

I am running up a new Bizhub C754e today with a FS-534 finisher and I am reminded of some problems with paper jams that I have had with this combination.
The first time we had trouble was with a customer who was an hour and a half drive away and was reporting "Jamming everywhere in the copier". Jamming everywhere usually means a jam in the finisher or towards the end of the paper path. Larger printers have multiple sheets of paper running through them at once to keep the time between prints as short as possible. A jam like this means that there is paper all through the machine when the jam occures and they all need to be removed before the machine will work again. This is described by normal people as jamming everywhere. In fact it is only jamming in the finisher.

I wasn't the first tech to have a look at the problem but the guy who was did a lot of testing but couldn't get it to jam. A couple of days later another call came in for the same problem so I went to have a look. All photocopiers keep a log of the latest jams including a code that describes where the jam occurred, the time, date and what paper was being used. When I looked at the log all I could see were document feeder jams. So I cleaned the ADF and replaced the feed rollers and then gave the machine a good test.

Since it was a decent drive to the office where the machine was located I really wanted to make sure that the problem was fixed but I had doubts. I was worried that we are missing something with jams not being logged so I turned on the option for the machine to display jam codes. Normally when there is a jam the machine will display a picture showing where paper needs to be removed from the machine but no information about what caused the jam. Now when there is a jam a code will be displayed on the screen. I asked the girl at reception if she could keep a manual log of any codes if the machine jams so we could have a better chance of fixing it.

Sure enough a couple of days later we got a call that the jamming had not stopped. I was surprised when I arrived that the receptionist had not only taken note of the lack of jam codes displayed but had used her phone to take pictures of the paper jammed in the machine before it was cleared. I was interested to see that not only wasn't the machine logging jam codes but won't display them either. The pictures though showed clearly that the front corner of the paper was catching at the finisher entrance. 

It didn't take too long after looking at the pictures that there was a groove cut into the plastic lower guide at the exit of the horizontal transport unit. 

The lower guide is removable (3 screws) and has a series of ridges that look like they are there to reduce the friction of the paper sliding over the plastic. However with the C754/FS-534 combo the edge of an A4 sheet lines up perfectly with the inside edge of the front most ridge. After a 200000 pages or so have gone through the paper actually cuts the plastic an causes a groove on the inside of this ridge. This causes the jamming.

To fix the problem we replaced this guide with a new one but that only fixed the problem for another 200000 pages and the jamming started again. So a final fix was to use a sharp knife to remove the bridge and then polish the plastic to smooth it out completely.

So the lesson here is to not always believe the logs.