Is the optical sensor light supposeto be green prior to feeding the paper?

I'm guessing by top feeder tray, you are referring to the manual feed tray.

If the paper is getting stuck midway into the printer, and you have taken the time to clear all paper jams, torn piece of paper, paper clips or staples that might act as an obstacle to the paper path, then usually the problem is a defective or non-operational optical sensor.

I had this happen to me on a Brother MFC-8840DN recently. I took some compressed air and pointed the air at what I felt was the area of the optical sensor. This helped blow the paper dust or loose toner powder from out of the optical sensor and the printer began working again just fine.

If you're not sure where the optical sensor is, after you have removed the toner cartridge and drum assembly, just spray compressed air over the entire area. You might wish to wear a dust mask or do this outside to prevent inhaling any paper dust or toner.

The small optical sensor usually has a small plastic arm attached to it with a flapper that moves in between a small "U" (The emitter and receiver are mounted in the sides of the U). This arm can get broken or jammed.

If cleaning the optical sensor doesn't work, then probably you will need to replace it. You can call Brother Customer Service at 877-436-2665 and see if they can give you the part number and sell you the part. If you can access the sensor, generally replacing it is pretty easy.

Let me know how it goes and please vote a Thumbs Up if you find this answer helpful.

paper start sensor is not functioning properly. clean it or replace it.

There is likely a loose connection going to the manual feed paper sensor.
The printer thinks there's paper in the manual feed, but of course since there isn't any paper there, when it tries to feed the paper in from the manual feed, the next paper sensor is not tripped, so it assumes there is a jam in the manual feed.
Start testing at the manual feed sensor, and work your way back to the board it connects to.
It may be the sensor itself just needs to be cleaned - these sensors are usually optical, and spraying canned air at it will often fix it up.
Also, make sure the lever that trips the sensor isn't sticking after using the manual feed.

Make sure the sensors on the feeder are clear. You either have optical sensors (look like little eyes) or mechanical sensors. If optical, make sure they are clean. If mechanical make sure the sensor is not pressed down at all. You might try holding it up as you feed the paper through. Also, check the green dial in your paper tray to make sure it is set to the right size and direction of paper.

Look if the input sensor is not stuck.
It can be a small "tongue" that tilts when the paper is inserted - some small piece of paper might block it from coming back to original position.
Another type of sensor is an optical one - inspect the feed area for any dust or paper particles. A good blow with compressed air might help.

Because the paper sensors are photo optic sensors, they probably do their reporting in the same ways as the photo optic sensors,

Their are sensors on top and bottom of cutter asm. Good chance one or more are dirty, blocked with paper shreds or just bad. Clean with compressed air and lightly moistened cotton swab.

I’m happy to help further over the phone at https://www.6ya.com/expert/jayw_0e86fb055a7b73de

These are made by Winsource Industries http://www.winsource-hk.com/ The contact information is Hong Kong. I haven't had any luck getting a replacement for one with a Limited Lifetime Warrany.
Good Luck -

This machine problem can be very involved.
A paper jam as described can be in any locations of the copier.
First of all when the toner-developer falls on the base of the paper feeder, it can contanimate all paper feed shafts and even sensors, and plug connections.
Worn feed rolls can cause the machine to jam. Clean the rollers and see if it corrects the problem.
A bent paper tray can cause the copy to skew, causing jams.
Sometimes the plasic paper path baffles are warped leaving narrow gaps in the paper feed path not allowing the paper to go through properly.
A bad paper feed sensor can cause inttermittant paper feed jams. This sensor is located just above the feed rolls. A involved process to take out without breaking the plastic components.
The machine has paper feed clutches located at the back of the feed rolls. To get to them it is also involved. Sometimes these clutches slip and will cause paper feed problems. There paper feed solinoids may operate intermittantly not allowing the paper feed clutch to operate correctly.
The main board can also cause these types of problems, not allowing the correct signal to operate the paper feed solinoids.
There is so much in this area to locate and isolate for paper feed problems.
If all else fails, call Xerox for a service repair.

I had the same problem with my Shredded. In the centre of the paper feed slot is a little sensor that detects when you put paper in, it breaks some sort of light beam that is connected to the motor circuit.

Over time paper dust gathers on this sensor, covering it completely and fooling the machine to think that there is ALWAYS a piece of paper being fed into the shredder, the result being that the motor just runs continuously.

Clear the dust from this sensor and you'll fix this particular problem - a toothbrush worked great for me - don't use it to clean your teeth afterwards :-)

FIXYA!!!