Patent ID: 8162459

Claim:
An ink cartridge comprising: a flexible ink bag which has ink sealed in advance in an inside thereof and which undergoes movement and is changed in thickness in accordance with a change in the amount of ink contained in the ink bag; a housing accommodating the ink bag, the housing having a side surface and a guide groove formed in the side surface; a plate connected to a surface of the ink bag for undergoing movement with the ink bag, the plate having a pin protruding toward the side surface of the housing, the guide groove being formed in a size allowing insertion of the pin and regulating movement of the pin during movement of the plate; a window provided at the side surface of the housing; a first reflecting plate having a first reflectivity and configured to be displayed by the window in a state in which the ink bag contains ink; and a slide member mounted to undergo sliding movement on the side surface of the housing and arranged slanted with respect to a sliding direction, the slide member having a guide hole into which the pin of the plate is inserted and a second reflecting plate having a second reflectivity different from the first reflectivity of the first reflecting plate, the second reflecting plate being configured to be displayed by the window in a state in which the ink bag does not contain ink; wherein when the plate undergoes movement with the ink bag in accordance with a change in the amount of ink contained in the ink bag, the pin of the plate moves along the guide groove of the housing and along the guide hole in association with the plate movement, the slide member slidably moves on the side surface of the housing by the movement of the pin along the guide hole, and, in accordance with the sliding movement of the slide member, the window displays the first reflecting plate when the ink bag contains ink and displays the second reflecting plate when the ink bag does not contain ink.