Liquid container, cartridge including liquid container, printing apparatus using cartridge and liquid-discharge printing apparatus

A liquid-discharge printing apparatus comprising:

• a printhead which performs printing by discharging ink;
• a liquid container which contains the liquid discharged from said printhead;
• scan means, holding said printhead and said liquid container, for scan-moving;
• optical means, provided near said scan means, having a light emitter to emit light onto said liquid container and a photoreceptor to receive reflection light of the light;
• and
• detection means for detecting existence/absence of the liquid contained in said liquid container, based on the reflection light of the light emitted onto said liquid container, received by said photoreceptor,
• wherein said liquid container includes an approximately-polygonal prism made of light-transmitting material, having a surface integrated with an external wall surface of said liquid container and a plurality of reflection surfaces, different from said external wall surface, which serve as an interface with respect to the liquid, having a predetermined angle with respect to an optical path of light emitted from the light emitter,
• and wherein said scan means holds said liquid container such that a lengthwise direction of said prism is diagonal to a scan direction of said scan means.

A liquid container comprising:

• a container containing liquid;
• a prism made of light-transmitting material, having a first surface to receive light emitted from an external device and a second surface to receive light reflected by said first surface and change an optical path to direct the light toward said external device, provided on a bottom of said container, projecting toward the inside said container from the bottom;
• and
• a groove or projection, provided around said prism or on said first and second surfaces of said prism, which absorbs said liquid by capillarity.

An ink tank detachably held on a tank holder, having a movable lever with a first engagement latch to engage with a first engagement hole provided on a side wall of said tank holder and a second engagement latch to engage with a second engagement hole provided on another side wall of said tank holder opposite to the side wall having said first engagement hole,

• wherein said ink tank has a positioning pin on its bottom surface, and said tank holder has a positioning hole to receive the positioning pin upon attachment of said ink tank to said tank holder,
• and wherein a prism is provided on an inner bottom of said ink tank such that said prism is positioned opposite to the position of an optical sensor for residual ink detection provided outside of said ink tank when said ink tank is attached to said tank holder,
• further wherein said prism is provided in a position between the second engagement latch and the positioning pin,
• further wherein the positioning pin and the positioning hole have thrust portions to thrust upon each other, and the thrust portion of the positioning pin has a flat surface.

A tank holder which detachably holds an ink tank, having a first engagement hole to engage with a first engagement latch of a movable lever provided on one side surface of said ink tank and a second engagement hole to engage with a second engagement latch provided on another side surface of said ink tank opposite to the side surface having the movable lever,

• wherein said ink tank has a positioning pin on its bottom surface, and said tank holder has a positioning hole to receive the positioning pin upon attachment of said ink tank to said tank holder,
• and wherein a prism is provided on an inner bottom of said ink tank such that said prism is positioned opposite to the position of an optical sensor for residual ink detection provided,outside of said ink tank when said ink tank is attached to said tank holder,
• further wherein said prism is provided in a position between the second engagement latch and the positioning pin,
• further wherein the positioning pin and the positioning hole have thrust portions to thrust upon each other, and the thrust portion of the positioning hole has a flat surface.