Samsung ML-2510 Laser Printer "triangle line symbol" Questions

line gone so two sides and bottom with dots shaped like a triangle in it. Is that the toner light or what is the problem please? The symbol for toner low is a box, without a top, with an arrow made of

...triangle with the exclamation mark, the piece of paper (i get this one), the beaker full of marbles, and then the two circles with a squiggly line coming out between them. I'm particularly interested ...

...triangle shape with the exclamation mark is still flashing. I have turned the printer off, only to turn it on again & have the printer voluntarily print out page after page of paper with one line of ...

...triangle symbol inside of a circle) for 5-8 seconds and the ink error ("ink has run out", etc.) indicators should extinguish; two common reset procedures are provided below (please refer to both ...