Ricoh Pro c901 Printing problem in Cyan Unit

[sri27679]

Hi Dear Techies

I have problem with my Ricoh Pro c901
in Cyan unit printing not coming in Paper center (Attached Photo)

i checked drum which is ok, and developer mag roller which is ok,
Shield glass which is ok , charge corona which is ok

and i swapped all the parts with another unit but problem is same in Cyan unit

if i keep on machine for a day (24 hrs ) the non printing gap is reducing

please help me

WhatsApp Image 2020-10-13 at 4.05.54 PM.jpg
Paper is printing in landscape

[slimslob]

Portrait and landscape have to do with how something is hung on the wall. It has nothing to do with how paper is fed through a printer. The proper terms to use are SEF, Short Edge First, and LEF, Long Edge First.

[sri27679]

Portrait and landscape have to do with how something is hung on the wall. It has nothing to do with how paper is fed through a printer. The proper terms to use are SEF, Short Edge First, and LEF, Long Edge First.

Yes it's LEF
I just mention to explain what is center

[bat]

There is something in the laser beam path, between shield glass and laser unit mirrors. Once I found a screw in the laser unit opening resulting in the same manifestation.

[sri27679]

There is something in the laser beam path, between shield glass and laser unit mirrors. Once I found a screw in the laser unit opening resulting in the same manifestation.

I inter changed laser units but problem is same

[mrwho]

I inter changed laser units but problem is same

When you took out the laser unit, did you take a peek at the slit on the machine body and could you see the drum without any problem?

[sri27679]

When you took out the laser unit, did you take a peek at the slit on the machine body and could you see the drum without any problem?

No I didn't take peek. yes drum is good . even i swapped with another unit drum

when i do process control the result is 61 for can unit

[mrwho]

Then I'd suggest taking out the laser unit and looking down on the hole through which the laser shines down onto the drum - I'd wager something's stuck there, blocking the path.