Canon DR-7550c scanner

[mntech]

Does anyone know why the scanner would stretch some of the text/image about an inch in from the lead edge? Its only stretching the text just slightly, so you can still read the text, it just make the text look weird. The rest of the page is fine.

We replaced the pickup, feed, and sep and it actually made the problem worse, stretching the text so much that you cant read it. Again only on the leading edge anywhere from an inch to inch and half in. When we put the old separation roller back in the problem wasn't as bad, but still noticeable.

To me it seems as the paper is being slightly delayed right after it passes the top side scanner. I've cleaned rollers, sensors, replaced sep motor, and I don't see anything that is catching the paper.

Thanks,
mntech

[Rachid.Akli]

Re: Canon DR-7550c scanner

Hello,

Is the issue the same in both sides when you read a document in recto-verso ?

Rachid.

[Rachid.Akli]

Re: Canon DR-7550c scanner

Hello again,

I suppose that your issue is in recto only.
The document leading edge speed is less than the reading speed because the registration rollers are not well feeding the documents. Verify the pressure between rollers 4 and 5 and between the lower platen roller 6 and the upper reading unit 16. If the pressure is "normal", replace them.

Roller arrangement.pdf


Rachid

[djwhoo]

Re: Canon DR-7550c scanner

Hello again,

I suppose that your issue is in recto only.
The document leading edge speed is less than the reading speed because the registration rollers are not well feeding the documents. Verify the pressure between rollers 4 and 5 and between the lower platen roller 6 and the upper reading unit 16. If the pressure is "normal", replace them.

[ATTACH]27686[/ATTACH]


Rachid

yea... the stretching only occurs one inch away from the leading edge and happens maybe for less than an inch. This all started to happen when i replaced the feed, pick up and separation rollers.. It was horrible stretching (an inch away from the lead edge) with the new separation roller and when i put the old one back on it improved.. The machine seems to function properly runs and feeds seemingly fine but obviously theirs a stall or maybe a buckle... Is there some kind of timing I can do with the service tool?

[djwhoo]

Re: Canon DR-7550c scanner

and its gotten worse.. ive been playing around with the pickup solenoid height and pickup sensor adjustments with really no luck. The drunification tool doesnt seem to help either i get a " yregist adjustment failed! over limitation value" error when i run the registration tool. when i run the feed operation all the sensors light up exept for the ultrasonic one in the middle above the sep roller. Is it supposed to give a reading when I run the feed operation in drunification?

[alliedofficeproducts]

Re: Canon DR-7550c scanner

To me this sounds as if the paper is hesitating as it passes over the scanning units. Check that the glass is firmly in place and that the paper is not hesitating there. Also, clean all of the transport rollers both on the lower and upper transport, especially right before and right after both scanning units. I use 50% isopropyl alcohol and have always had good results with it. Make sure on the upper transport that none of the rollers are binding as they rely on the lower rollers for their movement. For me, I have not seen feed and separator rollers cause an issue like this. I have, however, seen poor feed performance after cleaning the separator.

[djwhoo]

Re: Canon DR-7550c scanner

To me this sounds as if the paper is hesitating as it passes over the scanning units. Check that the glass is firmly in place and that the paper is not hesitating there. Also, clean all of the transport rollers both on the lower and upper transport, especially right before and right after both scanning units. I use 50% isopropyl alcohol and have always had good results with it. Make sure on the upper transport that none of the rollers are binding as they rely on the lower rollers for their movement. For me, I have not seen feed and separator rollers cause an issue like this. I have, however, seen poor feed performance after cleaning the separator.

I agree. Everything seems to be in place. and I have cleaned the rollers. The pressure seems good, though I cant figure out a real way to test the pressure between 4 and 5 ( registration rollers). but it seems like it hesitates right as its trying to reach the read rollers. I am going to have her run 2 sided tomorrow to see if it happens on the 2nd side. (I do no believe it will) I am very confident that it is just the hesitation.. I cant figure out why. Its driving me nuts and I dont want to buy parts just to try them. maybe the platen roller? Ive seen the platen roller on the 7090c cause jamming because it was worn down enough to actually "stick" or "grab the glass a bit. but they do seem still clean and "shiny".

Am i right in seeing that there is NO clutch in this machine?

[djwhoo]

Re: Canon DR-7550c scanner

this sensor... the ultrasonic.. Is it supposed to give you a reading when you run the feed test? the other sensors give me a reading but the ultrasonic never does anything..Why? and is there a way for me to test them individually? cannon dr-7550_sensor_check.jpg

[alliedofficeproducts]

Re: Canon DR-7550c scanner

No, I do not believe there is a clutch. The entire lower is driven by a belt and the upper is driven by the lower. You are right in that maybe the platen roller is worn enough to slip and when the next roller grabs the document it pulls as it should and catches the remainder of the document back up. If your rollers are "shiny" as you say then that could be an indication they have hardened up and causing the slippage.

[djwhoo]

Re: Canon DR-7550c scanner

No, I do not believe there is a clutch. The entire lower is driven by a belt and the upper is driven by the lower. You are right in that maybe the platen roller is worn enough to slip and when the next roller grabs the document it pulls as it should and catches the remainder of the document back up. If your rollers are "shiny" as you say then that could be an indication they have hardened up and causing the slippage.

Perfect...


I have ordered reg roller upper and lower and the platen roller.. fingers crossed.. ha

what about the drunification tool feed test with the ultrasonic sensor not responding?

[djwhoo]

Re: Canon DR-7550c scanner

Hello,

Is the issue the same in both sides when you read a document in recto-verso ?

Rachid.

only side 1

[alliedofficeproducts]

Re: Canon DR-7550c scanner

I have never had the need for using any of the diagnostics on this machine so I can not give you an answer on that. My problems on these Canon units have always been mechanical parts breaking or wearing out.

[Rachid.Akli]

Re: Canon DR-7550c scanner

this sensor... the ultrasonic.. Is it supposed to give you a reading when you run the feed test? the other sensors give me a reading but the ultrasonic never does anything..Why? and is there a way for me to test them individually?

The Ultrasonic sensor has nothing do to with this issue. Its function is to prevent document double feeding.

Rachid.