Problem with printer

Hello,
Sir i've a problem with my printer is Ink jet and HP compeny. And 3 in one i means printer , photocopy and scaner both are there. Some time started to do photo copy they print some part and remain part failed to print so please tell me what a problem with my printer.
And also when i print some thing with computer they print every things fastely but can't print slowly. so again again i want to tell plz tell me about this problem.
Thanks
kamlesh