The display says "Paper Jam / Open Left Cover" without any code. I don't think the jam is real.

I put a camera inside the paper tray and upload the video to youtube

1. At 0:03, the cassette pickup roller (CPR) would push the top paper forward
2. At 0:04, the CPR would push that top paper once more. After that, the top paper completely goes in.
3. At 0:06, the CPR would push the 2nd paper.
4. Then the printer says it gets a paper jam.

The top of the 2nd piece of paper is right at the end of the registration roller. The paper doesn't go a bit beyond the registration roller. After I open the left cover, I can't just pull that single piece of paper out. I have to manually roll the roller to get the 2nd paper out.

On page 111, the service manual talks about a "Retry Pickup":

• If the registration sensor(SR11) does not detect paper within a specific period of time after the cassette pickup roller has started to rotate, the machine will start to rotate the cassette pickup roller once again to execute a retry pickup operation
• If the registration sensor (SR11) still does not detect paper within a specific period of time after executing a retry pickup 3 times, the machine will identify the condition as a jam and will indicate a jam message on the LCD of its control panel

At first, I thought maybe SR11 was faulty and couldn't detect the paper. That would make the machine do that "retry pickup".

But I am not sure because I *can't* even see an error code for the jam.

Does a jam always have an error code? If that is the case, how to see that code?

I have tried:

1. Go into maintenance mode ([additional function], [2], [8], [additional function])
2. Clear history of error
3. Copy something and let the paper jam.
4. Print the history of errors

But that history is blank.

I also did several sensor tests using the normal sensor mode (not the latch mode).

Testing the Sensor for Papers in Tray

Test of the cassette paper sensor (SR9):

• When I remove all papers in the paper tray, the display says "CAS 0".
• After I put papers back into the tray, the display says "CAS 1".

When the tray has papers, CAS = 1. When the tray has no paper, CAS = 0.

What I see: 0/tray has no paper, 1/tray has paper.

But page 224 (F14-14) of the manual says the exact opposite: "CAS: Cassette paper sensor (SR9): 0/Document presence, 1/Document absent".

Testing the Registration Sensor

• When I did a sensor test after the paper jam, I saw "REG 1".
• After I removed the paper, I saw "REG 0".

What I see: 0/no paper, 1/has paper.

The manual says the exact opposite: "REG: Registration sensor (SR11): 0/Document presence, 1/Document absent”

Testing the Delivery Sensor

• I ask the printer to make a copy. Before the printer completes the print, I open the left cover.
• Before I remove the half-printed document, the sensor test says “DEL 1 0”.
• After I remove the half-printed document, the sensor test says: “DEL 0 0”

What I see: 0 0/no paper, 1 0/has paper.

The manual says the same thing: "Delivery sensor (SR5): 1/Document presence, 0/Document absence.”

⟐ Commented August 10, 2023 at 7:39 MST