Since when ?

123456
Across
  1. 1. Best Teacher Eveeeeerrr!
  2. 4. a measure of the sharpness of an image
  3. 6. an invention or machine used to perform simple tasks
Down
  1. 2. a record of money spent or received
  2. 3. a machine that makes printed copies from a computer
  3. 5. something that is invented.