Patent ID: 6767075
Filing Date: 2004-07-27
Classification: B41J

Abstract:
An image forming device for forming an image with an ink jet method, comprising:an ink tank which is detachable on a carriage; a prism disposed in said ink tank, said prism being covered with ink when the tank is filled with ink and being exposed when the tank is empty; an optical ink sensor that has a light emitter for projecting light onto said prism and a light receiver for receiving a reflected light of the projected light to detect a presence/absence of ink in said ink tank; and a reflector movable between a first position and a second position according to whether or not said ink tank is installed on said carriage; wherein said reflector, in said second position with the ink tank installed, reflects the light from said optical ink sensor back to said optical ink sensor and wherein said reflector, in said first position with no ink tank installed, does not return the light from said optical ink sensor back to said light receiver; said carriage including an ink tank holder for holding the ink tank on said carriage and a resilient member normally urging said movable reflector in one direction for placing said reflector in said first position, one end of said reflector being supported on the ink tank holder, and wherein, when the ink tank is installed in said ink tank holder, said reflector is pressed down against a resilient power of said resilient member to place said reflector in said second position.