Original left on glass part 2

Not long after my last post about dirt on the scanner glass causing the copier to constantly detect A3 size paper on the glass I got a call about a machine constantly detecting A4 on the glass. The machine is a Bizhub C364e that I had recently replaced a board in and the problem had occurred repeatedly since that repair. 

Since the last thing to happen to the copier was the board replacement I first had another look at that board to see if a connector was loose. I pulled the copier out away from the wall and took the rear covers off to have a look but found nothing wrong. I tested the copier before putting it back together and could no longer get it to detect A4 when there wasn't one on the glass. Yay, fixed. I put the covers back on and pushed it back into place and tested it again and the problem was back. Hmmmm.

As in my previous post the copier looks for an original on the glass when the ADF is lowered. With the last problem it was the original length sensor that was detecting something that wasn't there. This machine was using the scanner CCD to detect something that isn't there. Testing different combinations of A4, A4R and A3  showed me that the problem was towards the front of the scanner because it couldn't tell the difference between A4 and A4R. The copier was seeing something at the front of the glass that it was interpreting as an A4 length piece of paper.

The problem only occurs when the machine is against the wall so I pulled it out away from the wall and tried again. No problem. I have an idea. I look at the carpet for divots left by the copiers castors and found none. This is really nice carpet and the machine has not left a mark on it since it was installed. This also means that I don't know where the machine was exactly positioned when installed. Aha!

When I had the original problem I moved the machine back against the wall and a little to the right away from a shredder that was there. I thought it was a little close and there was space for it to be moved so I did. When I pushed the copier back 10cm to the left closer to the shredder the original detection problem went away. So the position of the copier was causing the problem. Why?

With the copier 10cm to the right the scanner mirrors are directly underneath a set of ceiling lights and when the ADF is lowered the scanner "sees" the light and is interpreting it as light reflected off a piece of paper. A few cm in any direction puts the mirrors out from under the light and the scanner cannot see it.

So remember: Position, Position, Position! If the scanner is detecting something that isn't there try moving the copier a little.

Original left on glass

Today I went to a call for a Bizhub C754e that was constantly complaining that an original had been left on the glass and was not allowing users to copy or scan until it had been removed. However nothing was on the glass to be removed. This is not the first time I had seen this.
Switching the machine off and on again would allow users to use the copy and scan options if the document feeder was used until the document feeder (ADF) was lifted and an original placed on the glass. The problem can be replicated by simply lifting the ADF and closing it without putting an original on the glass. The detected original on the glass was always A3. The fault: dirty or streaky glass.
When the ADF is lowered it activates a switch at the back which triggers the scanners original detection. You can see this as the scanner lamp coming on when the ADF is still raised about 20 degrees. The reason the lamp comes on is because the machine is using the scanner to look for the width of an original. It is done before closing to get the contrast of the paper against the open platen cover. But this isn't the problem area.
At the other end of the scanner bed is one or more sensors that are used to detect the originals length. This is what detects the difference between A4 and A3. It consists of an infrared LED and a detector. Infrared light is shone up at the original and if an original is present will be reflected back at the detector. This can be tested in Sensor Check under State Confirmation in Service Mode.
But if there is no original what is the sensor detecting?
The first time I saw this was in an office where the copier was located near a kitchen. It seems that someone in the office took it on themselves to clean the scanner glass and used the conveniently located dishwashing soap to do it. The soap left a film on the glass that looked clean but was refelecting the infrared light back to the sensor. I gave the glass a good polish with a dry cloth and the problem went away.
However today's machine is not located near a kitchen nor had anyone owned up to cleaning it recently. But after giving it a good clean and polish the machine started working again.
Another thing to keep in mind is that we have had problems with a copier that would have this problem only late in the day. About 4pm this problem would happen but the next morning it would be fine. After arranging to have a tech arrive after 4pm it quickly became clear that the machine was near a window and the afternoon sun would shine through into the scanner. It was the sun light messing with the original length sensor and of course the next morning the sun would be shining from a different direction. That was easily fixed by closing the curtain.

Bizhub C35 miss feeding

Once again I got a call to fix a jammed Bizhub C35 that the customer could not find the jam. The simple answer to this is that the machine has not jammed. If the user had actually read the screen they would see that the message on the screen says that there has been a miss feed in the tray and can the user check the paper in the tray then open and close the right hand side door. It does not say the word "Jam" anywhere.
The problem occurs when the machine tries to feed the paper during printing but is unable to pick up the sheet from the tray and hence a miss feed. Since no paper actually moved from the tray there is no jam but the error message on the screen looks similar to that of a jam with the message to open and close the right hand side door. The reason to open and close the door is that this is the way that the machines controller clears the error message from memory. However, since it looks like a jam screen most users expect to find a sheet of paper inside the right hand side door and believe that the machine is broken because there is none.
So for these cases I explain that if there is a miss feed displayed on the screen then they need to check the paper loaded in the tray and this is most likely what they will find:

The most common cause is that a sheet of paper is sticking out to the right from somewhere in the middle of the stack of paper. The part that sticks out folds up along the inside of the tray. As the top sheets are fed into the machine the stack decreases until the sticking out sheet gets between the top sheet and the feed roller. I don't know how this happens but it has happened many, many times.

Since the feed roller is mounted to the paper tray it is easy to test the feed by turning the roller by hand. If the paper doesn't feed check that the top sheet is touching the roller. If it is check for the sticking out sheet in the middle of the stack.

P.S. I just had this same problem on an Okifax F-305 so it is not just the Konica machines that do this. The Oki also made a loud shuddering noise as the feed roller skipped across the top of the paper.

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.

A cockroach on the laser

I got a call to fix a Bizhub C364e that was reported to not be printing all of the text on documents. When I arrived I was shown samples of some black and white documents with voids at diferent locations on the pages. So to start with I printed out the C, M, Y, K gradation test prints and this is what I got:

The magenta print was from the first try. I had no idea what caused the marks so I pulled the drum out and had look at the charge unit but didn't see anything so I shone my torch into the machine to have a look at the developer unit. I couldn't see anything on the mag roller but am sure I saw a shadow move under the cyan unit. After a bit more looking I didn't see anything so tried the gradation prints again. This time the colours were fine but I had a void through the black as seen in the above picture. So I am thinking what the hell could cause a void to move from one image unit to another?

I pulled the black drum out and shone my torch into the machine and again saw something move over the laser glass and disappear under the drum mounting rail. So I got down lower and looked into the hole for the laser glass cleaning wand and got face to face with a medium size cockroach. It was sitting on top of the laser unit and seemed to be dazed. My guess is that it was walking back and forth across the laser unit occasionally blocking the path of the lasers and causing the voids in the prints. The dazed look was probably because the roach had been blinded by the lasers. 

As I watched it crawled right and up toward the registration rollers. I had to get it out because I didn't want it to make a mess on the laser glasses or worse. What would happen if it got into the high voltage supply behind the image units? 

Since I last saw the roach heading toward the rego rollers I opened the right hand door of the machine and was sure I saw something disappear into the tray 1 feed station so I pulled all that out. Nothing there. So I pulled the registration assembly out. Still nothing. So it must still be on the laser unit so I pull all the drums, developer units and image transfer belt out but I still can't see it. Next out comes the power supply and then the laser assembly.

I look into the now hollow machine and see no sign of the cockroach. 

I look down at the laser unit in my hands and can see a leg poking out from underneath the end of the laser unit. I carefully tip the laser onto its side and the cockroach immediately runs and hides in a small hollow space next to one of the skew adjustment motors. Aha, cornered.

At this point I think I should mention that I have an irrational fear of anything with more than four legs. Insects really creep me out, spiders are worse and the bigger they are the easier it is see how freaky looking they are. So being this close to a decent size cockroach is really getting my heart pounding. But this copier must be fixed!

So I stick my screwdriver into the hole and flick the cockroach out. It went nuts on the floor trying to find a place to hide and I dropped the laser unit and both tried to jump on the cockroach while at the same time jump away from it. Unfortunately with all the parts I had pulled off the photocopier spread around the floor around me the cockroach had many places to hide. 

So there I am in the middle of this office shoving copier parts aside with one foot and stamping the floor trying to end this cockroach. I am sure I didn't impress any of the girls working there. But I did get the cockroach.

After that I put the copier back together again and everything works as it should. 

I am just glad it wasn't a big Huntsman spider in there or I would have had to call another tech to come and get it out. Either that or write off the machine.

Tape on toner cartridge

This is quick but it made me laugh. I was working on a photocopier and noticed a used toner cartridge on the floor next to the machine waiting for the cleaner to hopefully pick it up. What got my attention though was the packing tape was still covering the shutter on the cartridge.

So the toner had been taken out if it's box and jammed into the machine without the user spotting this tape. Amazingly the tape tore and stretched to allow the shutter to open and the machine to work. If it didn't I am sure I would have been called to fix it.

An Unknown error

Yesterday I got asked help with a Bizhub C754e that had some scanner problems. Most mornings the machine would have a C-9401 error when first used. According to the manual C-9401:

While this seems to indicate that the exposure lamp is the fault I was asked to change the CCD first. We didn't have a new CCD in stock but we did have a Bizhub C654e that was being stripped for parts that I could take the CCD out of. 

I went out to the C754e first thing in the morning to find the scanner had been locked out and the history showed that the C-9401 error had caused this. The actual swapping of the CCD was straight forward as was getting it lined up.

However when I powered up the mc I was given a C-D291 error. When I looked up the code in the manual I found an entry for the code but the only description there was "Unknown". What does that mean?

I knew that it was most likely caused by the CCD so I checked that all the cables were seated correctly but that was ok. The only thing that I could think that was different between this CCD and the original was the firmware. The manual never mentioned updating the firmware when installing the new CCD but the manual also doesn't mention anything about using a 2nd hand CCD either. 

The machine already had the latest firmware loaded on it as did the machine I took the CCD out of but I loaded up this firmware again, rebooted the machine and now it works.

So if you have a C-D291 error or other unknown error try reloading the firmware, you might get lucky. Also changing the CCD fixes the C-9401 error.