Horizontal lines skewed and misprint

Hi there

I have a canon pixma 700. Whenever I print anything, the printer distorts the horizontal lines. I did a test print and tried to align the print heads but the problem is still not solved. For example if I print a grid or a table - the vertical lines print in a solid line but the horizontal lines are sort of like this: -_-_- it prints every alternate line higher. How can I solve this problem?