Canon Mp500 - What Are These Tubes? - Cleaning Problem Printing Black Pigment

[PeterBJ]

Does anyone have any advice on my outstanding problem - what to do with those two tubes that may lead to the wipers?

I have not had a purge unit disassembled, so I don't know if the wiper contains valves and similar, so I can only suggest to check that all hoses are properly attached. After the printer is assembled I suggest to do turbguy's purge unit test found in this post: http://www.printerknowledge.com/threads/urgent-help-canon-ip4920.7972/page-4#post-66333

The name purge unit explains why the service manual hos no info about servicing it. It is replaced as a complete unit in servicing.

 

[The Hat]

I have cleaned two wiper box units and neither of them had anything inside them but sponge pads, no pipes attached.

 

[PeterBJ]

I have 3 defunct iP4000 kept for spare parts. Maybe I should take one apart and study the wiper-purge pad connection?

 

[The Hat]

I have 3 defunct iP4000 kept for spare parts. Maybe I should take one apart and study the wiper-purge pad connection?

Isn’t it a bit late Peter for a new year’s resolution ?

 

[PeterBJ]

Here are two scans of the top and bottom of the purge unit from an iP4000. This purge unit is different from the i965 purge unit, as it has both a stationary and a moving wiper. Two hoses go to the stationary wiper that cleans the moving wiper, so there are no hoses to become disconnected during use. I hope this purge unit is similar to the purge unit in the MP500.

 

[Robert the Bruce]

Thanks @PeterBJ but the MP500 purge unit doesn't seem to be quite the same.
I've attached an image of the top of the purge unit (still in situ) with the wiper retracted. The mystery tubes are attached to the rocker arms, which do not appear to be attached to anything else! They rock together, then one after the other, when the cams are turned using the cog on the right of the unit (which also moves the wipers of course).
There do not appear to be any tubes connecting to either the moving or stationary wipers, unless my eyes deceive me. I have no idea where the ink goes from these; perhaps it just drips down into the waste ink pads below the unit.
The stationary wiper pivots at the point shown when it is contacted by the moving wipers.

 

[turbguy]

I think the other tubes that resist cleaning go to the purge station to let air in a selected times. They are connected to cam-operated valves...are there additional connections on the edges of the purge pad?

 

[PeterBJ]

Thanks for that info turbguy, there is much I don't know about purge units. The iP4000 purge unit also has these two cam operated valves under the stationary wiper. Do they only let in air and don't suck away ink from the stationary wiper? If so they probably won't need cleaning?

Robert the Bruce said:
I've attached an image of the top of the purge unit (still in situ)

I wouldn't remove the purge unit. It took quite a lot of disassembly to remove it from the iP4000, and it was also complicated to reassemble the printer. I only did it because the printer is damaged beyond repair and only kept for spares.

You can see the rocker arms in my first picture at the lower left corner. They are positioned close to the micro switch that is a position sensor for the cam operating the rocker arms and valves, so the design of this purge unit is different from yours.

I have an iP4200 with a damaged print head and possibly also damaged logic board. The iP4200 uses the same print head as the MP500, suggesting that the print engine is the same or similar. The purge units look very similar in the parts catalogs even if the parts numbers are different, so I can try to get a couple of decent photos of the purge unit in situ.

 

[The Hat]

My printers seem to be different also and appear to have two sorts of wiper systems and don't have any tubes attached to them, this wiper box was very easy to remove just one screw holding it on.

I only removed it to gain access to the purge unit waste pipe to fit an external waste ink tank.

P.S. welcome back turbguy, I was wondering if you got any sunburn just to make the locals jealous like..

 

[Robert the Bruce]

I think the other tubes that resist cleaning go to the purge station to let air in a selected times. They are connected to cam-operated valves...are there additional connections on the edges of the purge pad?

It does not appear that there are. You may be right in thinking they are air inlets, in which case I think I will leave them alone.