1. A cooling device for an internal combustion engine, comprising:
a coolant water passage formed in said internal combustion engine;
a radiator configured to cool coolant water;
a radiator circulation passage configured to allow coolant water discharged from said coolant water passage to pass through said radiator and return to said coolant water passage;
a bypass passage configured to allow coolant water discharged from said coolant water passage to return to said coolant water passage without passing through said radiator; and
a thermostat valve connected to said radiator circulation passage and said bypass passage,
said thermostat valve being switched in accordance with a temperature of coolant water flowing in said thermostat valve to either a closed state of interrupting coolant water from said radiator circulation passage and outputting coolant water from said bypass passage to said coolant water passage or an opened state of outputting coolant water from said radiator circulation passage and coolant water from said bypass passage to said coolant water passage,
said cooling device further comprising:
a pump configured to circulate coolant water;
a first temperature sensor configured to detect a temperature of coolant water in said coolant water passage;
a second temperature sensor configured to detect a temperature of coolant water in said radiator circulation passage; and
a diagnosis unit configured to estimate a temperature of coolant water in said radiator circulation passage based on a leakage flow rate, which is set as a flow rate flowing through said radiator circulation passage even when said thermostat valve is in the closed state, and an output of said first temperature sensor, and perform a failure diagnoses for said thermostat valve based on a difference between an estimated temperature and a detected temperature of said second temperature sensor,
said leakage flow rate during operation of said pump being set to be a larger value as compared to said leakage flow rate during stopping of said pump.
2. The cooling device for an internal combustion engine according to claim 1, wherein said leakage flow rate for a large flow rate of said pump or a large physical quantity related to a flow rate of said pump is set to be a larger value as compared to said leakage flow rate for a small flow rate of said pump or a small physical quantity related to the flow rate of said pump.
3. The cooling device for an internal combustion engine according to claim 1, wherein said diagnosis unit determines that said thermostat valve is failed when a ratio of time with a detected temperature of said second temperature sensor higher than said estimated temperature is higher than a predetermined value.
4. The cooling device for an internal combustion engine according to claim 1, wherein said pump is an electric water pump driven by an electric motor.
5. The cooling device for an internal combustion engine according to claim 4, wherein said physical quantity includes at least one of a rotation speed of said electric water pump, a rotation speed of said internal combustion engine, a intake amount of said internal combustion engine, and a load of an air-conditioning heater.
6. The cooling device for an internal combustion engine according to claim 1, wherein said pump is a mechanical water pump driven by said internal combustion engine, and
said physical quantity is a rotation speed of said internal combustion engine.
7. A failure diagnosis method for a cooling device for an internal combustion engine,
said cooling device including:
a coolant water passage formed in said internal combustion engine;
a radiator configured to cool coolant water;
a radiator circulation passage configured to allow coolant water discharged from said coolant water passage to pass through said radiator and return to said coolant water passage;
a bypass passage configured to allow coolant water discharged from said coolant water passage to return to said coolant water passage without passing through said radiator; and
a thermostat valve connected to said radiator circulation passage and said bypass passage,
said thermostat valve being switched in accordance with a temperature of coolant water flowing in said thermostat valve to either a closed state of interrupting coolant water from said radiator circulation passage and outputting coolant water from said bypass passage to said coolant water passage or to an opened state of outputting coolant water from said radiator circulation passage and coolant water from said bypass passage to said coolant water passage,
said cooling device further comprising:
a pump configured to circulate coolant water;
a first temperature sensor configured to detect a temperature of coolant water in said coolant water passage; and
a second temperature sensor configured to detect a temperature of coolant water in said radiator circulation passage,
said failure diagnosis method comprising the steps of:
setting a leakage flow rate flowing through said radiator circulation passage even when said thermostat valve is in the closed state;
estimating a temperature of coolant water in said radiator circulation passage based on said set leakage flow rate and an output of said first temperature sensor; and
performing a failure diagnosis for said thermostat valve based on a difference between the estimated temperature and a detected temperature of said second temperature sensor,
in said step of setting, said leakage flow rate during operation of said pump is set to be a larger value as compared to said leakage flow rate during stopping of said pump.
8. The failure diagnosis method for a cooling device for an internal combustion engine according to claim 7, wherein in said step of setting, said leakage flow rate for a large flow rate of said pump or a large physical quantity related to a flow rate of said pump is further set to be a larger value as compared to said leakage flow rate for a small flow rate of said pump or a small physical quantity related to the flow rate of said pump.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A developing device, comprising:
a developing agent housing chamber which houses a non-magnetic one component developing agent, and which extends in a vertical direction, and has an aperture, in a lower portion thereof, that is in opposition to an image carrier that forms an electrostatic latent image;
a developing roller which is provided in the aperture and whose peripheral surface is partly exposed from the aperture to form a developing portion with the image carrier, and which carries the non-magnetic one component developing agent on the surface of the developing roller and transports the developing agent by rotation from the developing agent housing chamber to the developing portion, in order to develop on the developing portion, the electrostatic latent image of the image carrier;
a regulating blade, which is disposed higher than the center of rotation of the developing roller and is disposed to contact the surface of the developing roller in the vicinity of the aperture on an upstream side of the developing portion, in a transport direction of the developing roller, and which regulates a thickness of the non-magnetic one component developing agent transported on the developing roller;
a supply roller which is disposed within the developing agent housing chamber to pressure-contact the developing roller on the upstream side with respect to the regulating blade in the transport direction of the developing roller, and which supplies the non-magnetic one component developing agent within the developing agent housing chamber to the surface of the developing roller;
an agitator which is disposed higher than the developing roller, the regulating blade, and the supply roller, and which agitates the non-magnetic one component developing agent within the developing agent housing chamber; and
a developing agent ingress prevention member disposed higher than the supply roller, and lower than the agitator, wherein
a side surface or edge portion of the developing agent ingress prevention member in the vicinity of the developing roller is higher than the topmost point of the supply roller, and lower than the lowermost point of a regulating nip formed by the contact of the developing roller and the regulating blade, and
the closest distance from the supply roller to a bottom surface of the developing agent ingress prevention member is greater than 0mm and less than 5mm.
2. The developing device as claimed in claim 1, wherein the developing agent ingress prevention member is supported cantilevered from an opposing side wall.
3. The developing device as claimed in claim 1, wherein a top surface of the developing agent ingress prevention member is sloping so that the side near the developing roller is lower.
4. The developing device as claimed in claim 1, wherein a projection surface in a vertical direction of the developing agent ingress prevention member overlaps less than half the area of a projection surface in a vertical direction of the supply roller.
5. The developing device as claimed in claim 1, wherein the supply roller is configured such that a metal core is covered by an elastic member.
6. The developing device as claimed in claim 1, wherein undulations are provided on the surface of the supply roller.
7. The developing device as claimed in claim 1, wherein the surface of the supply roller has pores.
8. The developing device as claimed in claim 1, wherein a peripheral speed of rotation of the supply roller is faster than 80mms.
9. The developing device as claimed in claim 1, further comprising a developing agent agitation member disposed above the developing agent ingress prevention member to extend in a direction of an axis of the supply roller.
10. The developing device as claimed in claim 1, wherein a surface roughness of the developing roller Ra is 0.8 or greater and 1.2 or less.
11. A process unit in an image forming apparatus having a latent image carrier that carries a latent image and a developing device that develops the latent image on the latent image carrier, the process unit comprising at least the latent image carrier and developing device held in a supporting member to be inserted into and removed from a main body of the image forming apparatus, wherein the developing device comprises:
a developing agent housing chamber which houses a non-magnetic one component developing agent, and which extends in a vertical direction, and has an aperture, in a lower portion thereof, that is in opposition to an image carrier that forms an electrostatic latent image;
a developing roller which is provided in the aperture and whose peripheral surface is partly exposed from the aperture to form a developing portion with the image carrier, and which carries the non-magnetic one component developing agent on the surface of the developing roller and transports the developing agent by rotation from the developing agent housing chamber to the developing portion, in order to develop on the developing portion, the electrostatic latent image of the image carrier;
a regulating blade, which is disposed higher than the center of rotation of the developing roller and is disposed to contact the surface of the developing roller in the vicinity of the aperture on an upstream side of the developing portion, in a transport direction of the developing roller, and which regulates a thickness of the non-magnetic one component developing agent transported on the developing roller;
a supply roller which is disposed within the developing agent housing chamber to pressure-contact the developing roller on the upstream side with respect to the regulating blade in the transport direction of the developing roller, and which supplies the non-magnetic one component developing agent within the developing agent housing chamber to the surface of the developing roller;
an agitator which is disposed higher than the developing roller, the regulating blade, and the supply roller, and which agitates the non-magnetic one component developing agent within the developing agent housing chamber; and
a developing agent ingress prevention member disposed higher than the supply roller, and lower than the agitator, wherein
a side surface or edge portion of the developing agent ingress prevention member in the vicinity of the developing roller is higher than the topmost point of the supply roller, and lower than the lowermost point of a regulating nip formed by the contact of the developing roller and the regulating blade, wherein
the closest distance from the supply roller to a bottom surface of the developing agent ingress prevention member is greater than 0mm and less than 5mm.
12. An image forming apparatus, comprising:
a latent image carrier that carries a latent image; and
a developing device that develops a latent image on the latent image carrier, wherein the developing device comprises:
a developing agent housing chamber which houses a non-magnetic one component developing agent, and which extends in a vertical direction, and has an aperture, in a lower portion thereof, that is in opposition to an image carrier that forms an electrostatic latent image;
a developing roller which is provided in the aperture and whose peripheral surface is partly exposed from the aperture to form a developing portion with the image carrier, and which carries the non-magnetic one component developing agent on the surface of the developing roller and transports the developing agent by rotation from the developing agent housing chamber to the developing portion, in order to develop on the developing portion, the electrostatic latent image of the image carrier;
a regulating blade, which is disposed higher than the center of rotation of the developing roller and is disposed to contact the surface of the developing roller in the vicinity of the aperture on an upstream side of the developing portion, in a transport direction of the developing roller, and which regulates a thickness of the non-magnetic one component developing agent transported on the developing roller;
a supply roller which is disposed within the developing agent housing chamber to pressure-contact the developing roller on the upstream side with respect to the regulating blade in the transport direction of the developing roller, and which supplies the non-magnetic one component developing agent within the developing agent housing chamber to the surface of the developing roller;
an agitator which is disposed higher than the developing roller, the regulating blade, and the supply roller, and which agitates the non-magnetic one component developing agent within the developing agent housing chamber; and
a developing agent ingress prevention member disposed higher than the supply roller, and lower than the agitator, wherein
a side surface or edge portion of the developing agent ingress prevention member in the vicinity of the developing roller is higher than the topmost point of the supply roller, and lower than the lowermost point of a regulating nip formed by the contact of the developing roller and the regulating blade, wherein
the closest distance from the supply roller to a bottom surface of the developing agent ingress prevention member is greater than 0mm and less than 5mm.