Toner-remaining-amount detection sensor and toner storage container provided therewith

1. A toner-remaining-amount detection sensor, comprising:

a rubber member which is formed of a thin film, arranged so as to face an inside of a toner storage container for storing toner, and elastically deformed in accordance with a change of toner pressure in the toner storage container;

an actuator which is arranged on an outside of the toner storage container while sandwiching the rubber member between the toner storage container and the actuator and which reciprocates in accordance with elastic deformation of the rubber member;

a transmission sensor which comprises a light detecting portion including a light emitting portion and a light receiving portion and which is arranged so that a light path of the light detecting portion is blocked or unblocked by reciprocation of the actuator; and

a holder member which comprises

an opening to which the rubber member is mounted and

a fulcrum for rockably supporting the actuator and which integrally holds the rubber member, the actuator, and the transmission sensor, wherein:

the actuator is supported by the holder member so as to move to a first position at which the transmission sensor detects that a toner remaining amount in the toner storage container is a predetermined amount or more when the toner pressure in the toner storage container acts on the rubber member, and to move to a second position at which the transmission sensor detects that the toner remaining amount in the toner storage container falls below the predetermined amount when the toner pressure in the toner storage container does not act on the rubber member; and

when the actuator is at the second position, the actuator partially comes into contact with the holder member so that a gap is formed between the actuator and the rubber member.

2. A toner-remaining-amount detection sensor according to claim 1 , wherein the rubber member comprises:

a spherical and thin-film-like toner detecting portion forming a convex onto the inside of the toner storage container;

a flange-like holder attachment portion fixed to an opening rim of the holder member and having a thickness larger than a thickness of the toner detecting portion; and

an annular step formed on a boundary between the toner detecting portion and the holder attachment portion on the convex side of the toner detecting portion.

3. A toner-remaining-amount detection sensor according to claim 2 , wherein the actuator comprises:

an arm portion rockably supported by the holder member;

a pressure detecting portion which approaches the toner detecting portion of the rubber member from a concave side;

a light blocking plate for blocking or unblocking the light path of the light detecting portion of the transmission sensor; and

a rib protruding beyond the opening rim from the arm portion in a radial direction of the opening of the holder member.

4. A toner-remaining-amount detection sensor according to claim 1 , wherein the actuator moves by its own weight from the first position to the second position.

5. A toner-remaining-amount detection sensor according to claim 2 , wherein the actuator moves by its own weight from the first position to the second position.

6. A toner-remaining-amount detection sensor according to claim 1 , further comprising urging means for urging the actuator to the second position.

7. A toner-remaining-amount detection sensor according to claim 2 , further comprising urging means for urging the actuator to the second position.

8. A toner storage container, comprising the toner-remaining-amount detection sensor according to claim 1 .