Sec. 7. When payable on demand. - An instrument is payable on demand:
(a) When it is so expressed to be payable on demand, or at sight, or on presentation; or
(b) In which no time for payment is expressed.
Where an instrument is issued, accepted, or indorsed when overdue, it is, as regards the person so issuing, accepting, or indorsing it, payable on demand.
EXPRESSED TO BE PAYABLE ON DEMAND
An instrument is payable on demand where it is expressed to be payable on demand, on sight, or on presentation
It is payable on demand also when no date of payment is specified
It is payable on demand when the time of payment is left blank or unfilled
INSTRUMENT ON DEMAND ONLY AS BETWEEN THE PARTIES
That after the date of maturity, the instrument can no longer be negotiated as to make the parties who acquire the instrument after the date of maturity holders in due course because they become holders thereof with notice that it is already overdue, as this can be determined from the face of the instrument itself