Temperature determining device, temperature correcting method, and image forming apparatus

• US 20040109490A1
• Filed: 12/02/2003
• Published: 06/10/2004
• Est. Priority Date: 12/06/2002
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakano, Masaaki, Fujimoto, Keisuke, Asakura, Kenji
• Granted Patent: US 6,964,515 B2
• Time in Patent Office: Days
• US Class Current: 374/133
• CPC Class Codes: G01J 5/16 Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables

Abstract

A temperature determining device is composed of a temperature detecting unit that detects a temperature of a determination object member based on an intensity of infrared rays from the object member, a unit for determining a temperature for correction that determines a temperature of an opposing member opposed to the object member or a temperature of a member whose temperature changes in correlation to a change in the temperature of the opposing member, and a calculating unit that corrects the detected temperature obtained by the temperature detecting unit using the temperature as the temperature for correction obtained by the unit for determining a temperature for correction. Thus, stable temperature determination can be performed accurately without being influenced by infrared rays from around a determination object member.

Claims

1. A temperature determining device, comprising:

a temperature detecting unit that detects a temperature of a determination object member based on an intensity of infrared rays from the object member;

a unit for determining a temperature for correction that determines a temperature of an opposing member opposed to the object member or a temperature of a member whose temperature changes in correlation to a change in the temperature of the opposing member; and

a calculating unit that corrects the detected temperature obtained by the temperature detecting unit using the temperature as the temperature for correction obtained by the unit for determining a temperature for correction.

2. The temperature determining device according to claim 1,

wherein the temperature detecting unit includes a thermopile that outputs a voltage corresponding to a temperature difference between a hot junction and a cold junction, and

the unit for determining a temperature for correction determines a temperature of the cold junction of the thermopile.

3. The temperature determining device according to claim 2,

wherein the calculating unit corrects the detected temperature using a first temperature for correction determined by the unit for determining a temperature for correction at a predetermined point in time before a point in time when the temperature detecting unit detects a temperature and a second temperature for correction determined by the unit for determining a temperature for correction at the point in time when the temperature detecting unit detects the temperature.

4. The temperature determining device according to claim 3,

wherein the first temperature for correction is determined when heating of the object member is started.

5. A temperature correcting method, comprising:

a first step of detecting a temperature of a determination object member based on an intensity of infrared rays from the object member;

a second step of determining a temperature of an opposing member opposed to the object member or a temperature of a member whose temperature changes in correlation to a change in the temperature of the opposing member; and

a third step of correcting the detected temperature obtained in the first step using the temperature as a temperature for correction obtained in the second step.

6. An image forming apparatus comprising a fixing unit that allows a toner image transferred on a transferring material to be fixed on the transferring material by heating the toner image under pressure,

wherein the fixing unit comprises:

a fixing member that is brought into contact with the transferring material so as to heat the transferring material;

a heating source that heats the fixing member directly or indirectly;

a temperature detecting unit that detects a surface temperature of the fixing member based on an intensity of infrared rays from the fixing member;

a unit for determining a temperature for correction that determines a temperature of a constituent member of the fixing unit opposed to the fixing member or a temperature of a member whose temperature changes in correlation to a change in the temperature of the constituent member; and

a calculating unit that corrects the detected temperature obtained by the temperature detecting unit using the temperature as the temperature for correction obtained by the unit for determining a temperature for correction.

7. The image forming apparatus according to claim 6,

wherein the fixing member is an open-ended tube or an endless belt.

8. The image forming apparatus according to claim 6,

wherein the fixing member has a thickness of 0.02 mm to 0.6 mm.

9. The image forming apparatus according to claim 6,

wherein a face of the fixing member opposed to the temperature detecting unit is a curved surface concave toward a side of the temperature detecting unit.

10. The image forming apparatus according to claim 6,

wherein a face of the fixing member opposed to the temperature detecting unit has a surface roughness Ra of not more than 0.2 μ

m.

11. The image forming apparatus according to claim 6,

wherein the unit for determining a temperature for correction determines a temperature of a member in the fixing unit opposed to the fixing member.

12. The image forming apparatus according to claim 6,

wherein the temperature detecting unit includes a thermopile that outputs a voltage corresponding to a temperature difference between a hot junction and a cold junction, and

the unit for determining a temperature for correction determines a temperature of the cold junction of the thermopile.

13. The image forming apparatus according to claim 12,

wherein the calculating unit corrects the detected temperature using a first temperature for correction determined by the unit for determining a temperature for correction at a predetermined point in time before a point in time when the temperature detecting unit detects a temperature and a second temperature for correction determined by the unit for determining a temperature for correction at the point in time when the temperature detecting unit detects the temperature.

14. The image forming apparatus according to claim 13,

wherein the first temperature for correction is determined when heating is started by the heating source.