JP2002296958A - Fixing device for electrophotographic printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device for an electrophotographic printer which stabilizes the print quality of any print form by raising the surface temperature of a heat roll to 180 to 190 deg.C regardless of the state at the time of power-on to sufficiently secure the fixing strength without damaging the heat roll. SOLUTION: The ambient temperature of a heat roll 6 and the start period at the time of power-on are measured, and a control part 14 stores a reference thermistor output value and controls turning-on/off of a heat generating lamp only in the case that these temperature and period meet a condition on which the reference thermistor output value is stored, and the control part 14 takes a thermistor output value stored in a storage device 15 as the reference value to control turning-on/off of the heat generating lamp in the other cases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for an electrophotographic printing device.

[0002]

2. Description of the Related Art FIGS. 6, 7 and 8 are schematic views showing an embodiment of a conventional fixing device. In FIG. 6, printing paper 1
The upper toner image 2 is softened by receiving heat from the back surface of the printing paper 1 from the preheating plate 4 having the heater 3 therein. The softened toner image 2 is fixed on the printing paper 1 by being conveyed by a heating roll 6 having a plurality of heating lamps 5 therein and a pressure roll 8 held by a support 7. The printing paper 1 sent out by the heating roll 6 and the pressure roll 7 is sent out to a paper folding unit 10 by a paper feeding roller 9.

FIG. 7 shows a heating roll 6 of a fixing device, heat generating lamps 5a, 5b, 5c and 5d, and thermistors 11a and 11d.
b, 11c, thermolight chip 12 and sensor head 1
FIG. 3 is an explanatory diagram showing a configuration of No. 3;

FIG. 8 shows the temperature around the heating roll from power-on to detection of the temperature of the thermolight chip and ON of the heat-generating lamp.
FIG. 4 is an explanatory diagram showing / OFF control. The heating lamp 5 is turned on at a fixed rate until the sensor head 13 detects that the thermolight chip 12 has reached a predetermined temperature. Next, the controller 14 updates and stores the thermistor output values of the thermistors 11a, 11b, 11c installed at positions facing the heat generating areas of the heat generating lamps 5a, 5b, 5c at the time of detecting the thermolight chip temperature as reference values, During printing, the control unit 14 controls the heating lamp 5 to be turned on at an arbitrary time and for an arbitrary time so as to match the thermistor output value serving as the reference.

[0005]

SUMMARY OF THE INVENTION In a conventional fixing device,
Heating lamp ON / OF by thermistor every time power is turned on
The reference thermistor output value for F control is updated and stored. However, in this control method, the reference thermistor output value greatly varies depending on the temperature around the heating roll at power-on. In particular, when the power is turned on when the temperature around the heating roll is high, such as immediately after printing is stopped, the temperature around the heating roll is higher than when the power is turned on from near room temperature, so that the reference thermistor output value becomes higher. If this operation is repeated, the reference thermistor output value will continue to rise until an error of abnormally high temperature of the heating roll is detected,
For control purposes, there is no upper limit for the heating roll temperature.

As a result, the temperature of the heating roll during printing is
For example, the temperature became high, such as 220 ° C., and problems such as damage and short life of the heating roll and unstable printing quality occurred.

SUMMARY OF THE INVENTION It is an object of the present invention to suppress variations in the surface temperature of a heating roll at each power-on, to ensure the fixing strength of the surface temperature of the heating roll at the time of printing, and to prevent the heating roll from being damaged, for example, 180 ° C. to 190 ° C. The purpose is to provide a control method.

[0008]

The object of the present invention is to dispose a plurality of heating lamps inside a heating roll of a pair of fixing rolls for fixing toner by heating and pressing, and to provide a predetermined interval in the axial direction of the heating roll. And a plurality of thermistors arranged at an interval with respect to the outer peripheral surface of the heating roll, and a thermolite chip provided on a part of the outer peripheral surface of the heating roll, and a thermolite chip disposed so as to be able to face the thermolite chip. And a control means for performing ON / OFF control of the heating lamp in accordance with the outputs of the two types of sensors or the output of one of the sensors. The heating lamp is turned on at a fixed rate until the thermolight chip reaches a predetermined temperature, and each thermistor output when the thermolight chip temperature is detected. In the heating roll temperature control with a start-up period for storing the value as a reference value to the control unit is accomplished by enabling detecting thermistor output value at the time of power-on. That is, the temperature around the heating roll at the time of power-on is detected by a thermistor, and the detected temperature is equal to or lower than a slice level, which is a condition for storing a reference thermistor output value, and the thermolight chip temperature is detected from power-on. The control unit updates and stores the reference thermistor output value only when the start-up period is longer than a predetermined time. When the temperature around the heating roll at the time of power-on is equal to or higher than the slice level and the start-up period is equal to or less than a predetermined time, the reference thermistor output value is not updated and stored, and the thermistor output value stored in the storage device is not updated. Use If the thermistor output value is not stored in the storage device and the surrounding temperature of the heating roll at power-on is higher than the slice level, do not start turning on the heating lamp until the thermistor output value becomes lower than the slice level. Is solved by

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS.
This will be described with reference to FIGS. 3, 4, and 5. FIG. 1 is an overall schematic configuration diagram of the fixing device of the present invention. FIG. 2 shows the heating roll 6 and the heating lamps 5a, 5b, 5c, 5d of the fixing device of the present invention.
FIG. 3 is an explanatory diagram showing the configuration of the thermistors 11a, 11b, and 11c, a thermolight chip 12, and a sensor head 13. FIG. 3 is an explanatory diagram showing the relationship between the start-up time and the temperature around the heating roll when the reference thermistor output value is stored. FIG. 4 is an explanatory diagram showing the relationship between the start-up time and the temperature around the heating roll when the thermistor output value serving as the reference is not stored but the thermistor output value stored in the storage device is used. FIG. 5 is an explanatory diagram showing the relationship between the start-up time and the temperature around the heating roll when the thermistor detection value at power-on is equal to or higher than the slice level in a state where the thermistor output value is not stored in the storage device.

Referring to FIGS. 1, 2, 3, 4, and 5,
6, 7, and 8 are denoted by the same reference numerals, and description thereof is omitted. Reference numeral 15 in FIG. 2 denotes a storage device.
For example, when the slice level as a condition for storing a reference thermistor output value is 100 ° C. and the rising period is 4 minutes, the temperature around the heating roll 6 at power-on is set to the thermistor 11 as shown in FIG. All the detected temperatures are 100 ° C. or less, and the sensor head 1
The controller 14 updates and stores the thermistor output value only when the time until the detection of the thermolight chip temperature in step 3 is 4 minutes or more. Only when the thermistor output value is updated and stored, the thermistor output value is updated and stored in the storage device 15.

[0011] As shown in FIG.
The ambient temperature is detected by the thermistor 11, and if any of the detected temperatures is 100 ° C. or higher, the thermistor output value stored in the storage device 15 is used instead of updating and storing the thermistor output value.

As shown in FIG. 5, when the thermistor output value is not stored in the storage device 15 and any of the thermistor detected temperatures at the time of power-on is 100 ° C. or more, the heating lamp 5 is not turned on. Control is performed to lower the surface temperature of the heating roll 6 and to start lighting the heating lamp 5 after all the thermistor detection temperatures have become 100 ° C. or less. By the above control, the variation of the reference thermistor output value at every power-on is reduced, and the surface temperature of the heating roll at the time of printing is set to a temperature at which the fixing strength can be sufficiently secured without damaging the heating roll, for example, 180 ° C. From 190 ° C. to 190 ° C., stabilizing print quality, securing fixing strength, and extending the life of the heating roll.

[0013]

According to the present invention, the variation in the surface temperature of the heating roll during printing due to the difference in the peripheral temperature of the heating roll at the time of power-on is, for example, from 180 ° C. to 220 ° C. to 180 ° C.
It is possible to greatly reduce the temperature to 190 ° C. As a result, the fixing strength can be sufficiently secured without damaging the heating roll, and the printing quality can be stabilized.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram of a fixing device of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a heating roll, a heat generating lamp, a thermistor, a thermolight chip, and a sensor head of the fixing device of the present invention.

FIG. 3 is an explanatory diagram showing a relationship between a rising time and a temperature around a heating roll when a reference thermistor output value is stored.

FIG. 4 is an explanatory diagram showing a relationship between a start-up time and a heating roll peripheral temperature when a thermistor output value serving as a reference is not stored but a thermistor output value stored in a storage device is used.

FIG. 5 is an explanatory diagram showing a relationship between a start-up time and a heating roll peripheral temperature when the thermistor output temperature at power-on is equal to or higher than a slice level in a state where a thermistor output value is not stored in a storage device.

FIG. 6 is a schematic diagram illustrating an example of a conventional fixing device.

FIG. 7 is an explanatory diagram showing a configuration of a heating roll, a heat generating lamp, a thermistor, a thermolight chip, and a sensor head of a conventional fixing device.

FIG. 8 is an explanatory diagram showing the temperature around a heating roll and ON / OFF control of a heating lamp from power-on to detection of a thermolight chip.

[Explanation of symbols]

1 is printing paper, 2 is a toner image, 3 is a heater, 4 is a preheating plate, 5 is a heating lamp, 6 is a heating roll, 7 is a support, 8
Is a pressure roll, 9 is a paper feed roll, 10 is a paper folding unit, 11 is a thermistor, 12 is a thermolight chip,
13 is a sensor head, 14 is a control unit, and 15 is a storage device.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ken Onodera 1060 Takeda, Hitachinaka City, Ibaraki Prefecture Inside Hitachi Koki Co., Ltd. (72) Inventor Masahiro Mizuno 1060 Takeda Hitachinaka City, Ibaraki Prefecture F-term in Hitachi Koki Co., Ltd. Reference) 2H033 BA01 BA11 BA31 BA32 BB18 BE01 CA03 CA41 CA45 3K058 AA12 AA42 AA43 BA18 CA23 CA61 CA91 CA92 CB02 CB19 CE17 CE23 CE25 CE26 CE31 DA02 GA06

Claims (4)

[Claims] 1. A plurality of heat generating lamps are disposed inside a heating roll of a pair of fixing rolls for fixing toner by heating and pressing, and are arranged at predetermined intervals in an axial direction of the heating roll, and the outer peripheral surface of the heating roll. And two types of temperature sensors comprising a plurality of thermistors arranged at an interval to each other, and a thermolight chip provided on a part of the outer peripheral surface of the heating roll and a sensor head arranged to be able to face the thermolight chip. And the outputs of the two types of sensors,
Or a control means for performing ON / OFF control of the heating lamp in accordance with the output of one of the sensors, and turning on the heating lamp at a fixed rate until the thermolight chip reaches a predetermined temperature; An electrophotograph wherein the thermistor output value at power-on can be detected in the heating roll temperature control having a start-up period in which each thermistor output value at the time of light chip temperature detection is stored in the control unit as a reference value. Fixing device of a printing system. 2. The condition for storing each thermistor output value at the time of detecting the thermolight chip temperature as a reference value in the control unit is as follows. 2. A fixing device for an electrophotographic printing apparatus according to claim 1, wherein a period until a thermolight chip temperature is detected is a predetermined time or more. 3. A storage device for updating and storing a thermistor output value each time a thermistor output value serving as a reference is stored in the control unit, wherein the storage unit stores the thermistor output value as a reference value in the control unit. 3. The fixing device for an electrophotographic printing apparatus according to claim 1, wherein in the case, the thermistor output value stored in the storage device is used as a reference value. 4. If the power is turned on at a slice level which is a condition for storing the thermistor output value as a reference value in the control unit in a state where the thermistor output value is not stored in the storage device, the heating is performed. The fixing of the electrophotographic printing apparatus according to any one of claims 1 to 3, wherein the heating lamp is not turned on until the temperature around the roll becomes equal to or lower than a temperature that is a condition stored as a reference value. apparatus.