JP2004205570A - Image forming apparatus and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can accurately and speedily detect the surface temperature of a heat roller without requiring many operation man-hours for data creation and a large capacity for data storage, and can be controlled without causing a fixing abnormal state such as damage to the heat roller or offset. <P>SOLUTION: The image forming apparatus including: a heat roller; a detection sensor which detects the surface temperature of the heat roller without being in contact with it; and a compensation sensor which detects the temperature of the detection sensor, is characterised by having: a storage means which stores a computation formula set so as to correspond with an area determined by a roller temperature range in which normal printing is performed; a computing means which computes the surface temperature of the heat roller by use of the computation formula based upon detection outputs from the detection sensor and compensation sensor; and a control means which controls supply of power from the heat source based upon the computation result and a target control temperature. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus having a heat roll type fixing device.
[0002]
[Prior art]
Conventionally, in a heat roller type fixing device, a non-contact type detection sensor (roller temperature detecting means) has been used to control the surface temperature of the heating roller in order to eliminate damage to the coating layer on the surface of the heating roller. A method has been adopted in which the surface temperature of a heating roller is measured by using a heating roller, and the surface temperature of the heating roller is controlled based on the measured value.
[0003]
However, non-contact type detection sensors have a problem that response is slow and accuracy is low.
(1) A surface temperature of the heating roller corresponding to the detection signal of the non-contact type infrared light receiving element (temperature detection sensor) and the detection signal of the thermistor element (temperature compensation sensor) is converted into a data table. A fixing device using a method of applying a detection output and a detection output of a temperature compensation element to correct a surface temperature of a fixing rotating body (heating roller) detected by a detection sensor (Patent Document 1) has been proposed.
[0004]
(2) A target set temperature (target control temperature) for controlling the temperature of the fixing roller (heating roller) is calculated as a function of a time measurement value obtained by measuring a lapse of time from power-on by a timer, and the calculation result is set as a target. As a control temperature, a fixing device that controls the surface temperature of a fixing roller based on the target control temperature has been proposed (Patent Document 2).
[0005]
[Patent Document 1]
JP 2001-215843 A (paragraphs 0042 and 0044, FIGS. 3 and 4)
[0006]
[Patent Document 2]
JP-A-5-289574 (paragraphs 0063, 0064, 0075 to 0079, FIG. 2)
[0007]
[Problems to be solved by the invention]
In the case of {circle around (1)}, the surface of the heating roller with respect to the detection output ERn of the detection sensor and the detection output EHn of the compensation sensor as shown in FIG. 4 (a data table diagram for calculating the surface temperature based on the detection output and the correction output). Although a correspondence table for the temperature TRn is required, it is necessary to create an enormous data table corresponding to various combinations of temperatures in order to perform precise temperature control. Tables also have the disadvantage of requiring a very large storage capacity.
In the case of (2), since the surface temperature of the fixing roller is detected only by the non-contact type sensor, the non-contact type detection sensor is affected by the ambient temperature and the operation state of the apparatus, and the correct surface temperature of the heating roller is obtained. Cannot be detected, and as a result, the target control temperature, which is a calculation result for correcting the surface temperature, does not become a correct value, so that the surface temperature of the heating roller controlled based on the target control temperature becomes inaccurate. There was a disadvantage that it was easy to end up.
[0008]
In order to solve such a drawback, a detection sensor for detecting the temperature of the heating roller and a correction sensor therefor are provided. For example, as shown in FIG. 5 (an explanatory diagram for calculating the surface temperature by a conventional single arithmetic expression). A method of setting a single arithmetic expression 1 for calculating the surface temperature over the entire range of the roller temperature and calculating the surface temperature by an arithmetic expression based on the output of the detection sensor and the output of the correction sensor was also studied. There is a disadvantage that the deviation of the result becomes large.
[0009]
The present invention has been made in view of such a problem.
That is, the surface temperature of the heating roller can be accurately and quickly detected without requiring a large number of man-hours for creating data or a large storage capacity for storing data, and fixing errors such as breakage or offset of the heating roller. The present invention provides an image forming apparatus which can be controlled without generating the image.
[0010]
[Means for Solving the Problems]
For this reason, the inventor has provided an arithmetic expression for calculating the surface temperature limited to the temperature range where accuracy is required, and based on the output values of the detection sensor and the compensation sensor at each time, the calculated heating roller The purpose of the present invention is to provide an image forming apparatus configured to control the temperature of the heating roller by comparing the surface temperature of the sheet with the target control temperature.
[0011]
Further, as shown in FIG. 3 (a graph of calculation results of a plurality of equations), a temperature range A (a temperature range in which the temperature control of the heating roller is to be performed) which requires accuracy in order to increase the temperature detection accuracy is further divided into, for example, two parts. Then, if the calculation results of the calculation formulas provided corresponding to the respective temperature ranges B and C are graphed, they do not become parallel and intersect like b and c, and in this case, the value of the calculation result is small. Paying attention to the fact that the surface temperature is closer to the actual surface temperature graph a, when calculating the surface temperature in the same range using multiple arithmetic expressions, the one with the smaller value of the calculation result is regarded as the surface temperature.
[0012]
Here, the temperature range in which the temperature control of the heating roller is to be performed means that the heating roller is accurately controlled (for example, ± 2 to 3 ° C. of the target value) in a standby period, a printing period, an energy saving operation period, etc., excluding a warm-up period. The surface temperature of the heating roller that needs to be temperature controlled refers to a temperature range of 80 to 220 ° C., and the roller temperature range in which normal printing is performed is a temperature range in which the surface temperature of the heating roller is 160 to 200 ° C. in a normal printing period. These are determined appropriately according to the specifications of the image forming apparatus including the developer.
[0013]
The above object of the present invention is achieved by the following means.
(1) An image forming apparatus including a heating roller heated by a heating source, a detection sensor for detecting a surface temperature of the heating roller in a non-contact manner, and a compensation sensor for detecting a temperature of the detection sensor.
A storage unit storing an arithmetic expression set corresponding to an area determined by a roller temperature range in which normal printing is performed, and the arithmetic expression of the heating roller in the arithmetic expression based on detection outputs of the detection sensor and the compensation sensor. An image forming apparatus comprising: a calculating unit that calculates a surface temperature; and a control unit that controls power supply to the heating source based on a calculation result and a target control temperature.
[0014]
{Circle around (2)} An image forming apparatus including a heating roller heated by a heating source, a detection sensor for detecting a surface temperature of the heating roller in a non-contact manner, and a compensation sensor for detecting a temperature of the detection sensor.
The roller temperature range for controlling the temperature of the heating roller is divided into one or more temperature ranges, and the detection output range of the compensation sensor is divided into one or more ranges. A storage unit that stores an arithmetic expression set corresponding to each of the regions defined by the range and the divided detection range of the compensation sensor, and a storage unit that stores the target control temperature and the detection temperature of the compensation sensor. Selecting means for selecting the calculated formula, calculating means for calculating the surface temperature of the heating roller with the selected formula based on the detection outputs of the detection sensor and the compensation sensor, and calculating the calculated result and the target control temperature. An image forming apparatus comprising: a control unit that controls power supply to the heating source based on the control signal.
[0015]
(3) An image forming apparatus including a heating roller heated by a heating source, a detection sensor that detects a surface temperature of the heating roller in a non-contact manner, and a compensation sensor that detects a temperature of the detection sensor.
The roller temperature range for controlling the temperature of the heating roller is divided into two or more temperature ranges, and the detection output range of the compensation sensor is divided into one or two or more ranges. Storage means for storing an arithmetic expression set corresponding to each of the areas defined by the divided detection ranges of the compensation sensor;
Based on the detection outputs of the detection sensor and the compensation sensor, calculating means for calculating the surface temperature of the heating roller with the plurality of set arithmetic expressions,
Comparing and judging means for setting a smaller value of the plurality of calculation results as a final surface temperature,
An image forming apparatus comprising: a control unit configured to control energization of the heating source based on the final surface temperature and the target control temperature.
[0016]
{Circle around (4)} Further, the detection output of the detection roller for detecting the temperature of the heating roller and the compensation sensor for detecting the temperature of the detection sensor are read, and the surface temperature of the heating roller set in the roller temperature range for normal printing is calculated. The arithmetic expression stored in advance is read, the arithmetic expression is calculated according to the detection output of the detection sensor and the compensation sensor, the arithmetic result is set as the surface temperature of the heating roller, and the surface temperature is compared with the target temperature. Controlling the temperature of the heating roller by using the control method.
[0017]
(5) Also, the detection output of the detection roller for detecting the temperature of the heating roller and the compensation sensor for detecting the temperature of the detection sensor are read, and the temperature of the heating roller set within the temperature range in which the temperature control of the heating roller is to be performed is performed. A plurality of pre-stored arithmetic expressions for calculating the surface temperature are read, and an arithmetic expression corresponding to the target control temperature and the detection value of the compensation sensor is selected from the read arithmetic expressions, and the detection of the detection sensor and the compensation sensor is performed. Image forming characterized by performing an operation of an arithmetic expression selected according to the output, making the operation result the surface temperature of the heating roller, comparing the surface temperature with a target temperature, and controlling the temperature of the heating roller based on the result. How to control the device.
[0018]
{Circle around (6)} The detection output of the detection roller for detecting the temperature of the heating roller and the compensation sensor for detecting the temperature of the detection sensor are read, and the temperature of the heating roller set within the temperature range in which the temperature control of the heating roller is to be performed is performed. A plurality of pre-stored arithmetic expressions for calculating the surface temperature are read, and a plurality of arithmetic expressions corresponding to the detection values of the compensation sensor are selected from the read arithmetic expressions, and selected according to the detection output of the detection sensor and the compensation sensor. And calculating the minimum calculation result among the calculation results as the surface temperature of the heating roller, comparing the surface temperature with a target temperature, and controlling the temperature of the heating roller based on the result. A method for controlling an image forming apparatus.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
[0020]
First, the outline of the image forming apparatus of the present invention will be described.
FIG. 1 is an explanatory diagram of an image forming apparatus showing an embodiment of the present invention.
[0021]
In FIG. 1, reference numeral 1 denotes an image forming apparatus, in which a document is placed on a document feeder table 21 of an automatic document feeder 2 and fed one by one by the operation of a feed roller 22; After being adjusted, the image is read by the image reading means 3 while being conveyed to the conveying drum 24 and rotated counterclockwise integrally with the drum surface. The paper is discharged to the paper board 25.
[0022]
In the image reading means 3, the first mirror unit 31 including the light source 311 and the mirror 312 sequentially illuminates the passing document at a position directly below the transport drum 24, and arranges the document at right angles to the moving direction of the document. The reflected light from the original is guided by the second mirror unit 32 having the mirror 321 and the mirror 322 to the linear imaging element 34 via the imaging lens 33 to form an image.
[0023]
When reading image information by placing an original on the platen glass 35, the original is controlled by a first mirror unit including a movable light source 351 and a first mirror 352, and a second mirror unit including mirrors 353 and 354. Is reflected by the imaging lens 33 to the linear imaging element 34 to form an image. The above is the image reading unit 3.
[0024]
The image information of the document read by the image reading unit 3 is subjected to image processing by the image processing unit 62, converted into a signal as image data, and temporarily stored in the storage unit 61.
[0025]
At the start of image formation, the image forming means 4 starts to operate, the image data is called from the storage means 61 and inputted to the image writing means 43, and a laser beam projected from a laser emitter (not shown) according to the image data is emitted. Scanning is performed in the main scanning direction by the rotation operation of a polygon mirror (no symbol), and an electrostatic latent image corresponding to image data of a document is formed on a photosensitive drum 41 to which a potential is applied by a charger 42.
[0026]
The electrostatic latent image is reversal-developed by the developing unit 44 to be a toner image.
The recording paper fed by any one of the feed rollers 52, 53, and 54 of each paper feed cassette of the manual paper feeding means 26 or the paper feeding means 5 containing the recording paper is transported by the transport rollers 55 and 56. The toner is fed to the transfer area of the photosensitive drum 41 in synchronization with the toner image by the timing roller 51.
[0027]
The toner image is transferred to the recording paper side by applying a voltage of the opposite polarity by the transfer device 45.
[0028]
The recording paper after the transfer processing is separated from the photosensitive drum 41 by the action of the charge eliminator 46, and is conveyed to the fixing means 47 whose temperature is controlled by the control means 6, where the pressure roller 475 presses and heats the heating roller 474 and the pressure roller 475. Thus, the toner is fixed and discharged onto the tray 57.
[0029]
Further, the photosensitive drum 41 is cleaned of the residual toner by the cleaning means 48, and the preparation for the next image formation is completed.
[0030]
In this embodiment, the fixing means 47 is used for a heating roller 474 in which an aluminum base 471 containing a halogen lamp heater 471a, which is a heating source, is coated with a heat-resistant release layer made of a fluororesin, and a heating roller. The pressure roller 475 is arranged in contact with and parallel to the axial direction of the heating roller, and is constituted by a pressure roller 475 in which a heat-resistant elastic layer made of silicon rubber is coated on an aluminum base, and the heating roller 474 is heated by a heating source 471a.
[0031]
In addition, the non-contact type detection sensor 472 for detecting the surface temperature of the heating roller 474 is positioned 0.2 to 8 mm from the heating roller, preferably 4.5 to 5. It is mounted 5 mm apart (d in FIG. 2).
[0032]
The compensation sensor 473 for detecting the temperature of the detection sensor is mounted at a position where the member to which the detection sensor is mounted does not directly receive heat radiation from the heating roller.
[0033]
Here, the mounting member of the detection sensor is selected from copper, aluminum, or the like having a high thermal conductivity, and the detection sensor and the compensation sensor can be thermally integrated by attaching the compensation sensor 473 in close contact with the mounting member. I can do it.
[0034]
Reference numeral 64 denotes a control unit for controlling the heating of the heating roller, and 65 denotes a calculation output unit for calculating the surface temperature of the heating roller, which will be described later in detail.
[0035]
FIG. 2 is a control block diagram according to the embodiment of the present invention.
In the figure, 47 is a fixing means, 474 is a heating roller, 471a is a heating source (hereinafter also referred to as a halogen lamp heater), and 475 is a pressure roller.
[0036]
Reference numeral 90 denotes a commercial AC power supply for the image forming apparatus, which is also a power supply for the fixing unit 47.
A heating control means 64 has a heating control member 642 for turning on / off the energization of the halogen lamp heater 471a by a relay or the like in response to an input to a control input 641.
[0037]
Here, the heating control member 642 may be one that can change the duty ratio of AC power such as a triac. In this case, the input to the control input 641 inputs a voltage proportional to the duty ratio.
[0038]
One of the halogen lamp heaters 471a is connected to the commercial AC power supply 90, the other is connected to the heating control means 64, and the commercial AC power supply 90 and the heating control means 64 are connected.
[0039]
Then, the detection sensor 472 receives the infrared rays radiated from the heating roller according to the temperature once to a black body, converts the amount of infrared rays into the temperature of the black body, detects the converted temperature with a thermistor or the like, and detects the surface temperature. It is configured to provide a detection output corresponding to.
[0040]
In this manner, the surface temperature of the heating roller 474 is detected by the detection sensor 472, and the output is connected to the input of the A / D converter 63 via the buffer 621.
[0041]
Here, an infrared sensor may be used as the detection sensor.
The compensation sensor 473 is composed of a thermistor, detects the temperature of the detection sensor 472, and has its output connected to the input of the A / D converter 63 via the buffer 622.
[0042]
Here, a thermocouple may be used as the compensation sensor.
Each digital output of the detection output of the detection sensor and the detection output of the compensation sensor of the A / D converter 63 is connected to a surface temperature calculating means 65 for calculating the surface temperature of the heating roller.
[0043]
The surface temperature calculation means 65 is based on the selection means 651 for selecting an arithmetic expression for calculating the surface temperature corresponding to the area including the target control temperature and the detection temperature of the compensation sensor, and the detection outputs of the detection sensor and the compensation sensor. Calculating means for calculating the surface temperature of the heating roller; comparing and judging means for setting the minimum calculation result among the calculation results as the surface temperature of the heating roller; and controlling the energization of the heating source based on the calculation result and the target control temperature. And control means 653 for performing the following.
[0044]
The storage means 61 has a register and a memory. The memory has a temperature control program for the heating roller, a target control temperature for a printer or the like, and a roller for controlling the temperature of the heating roller as shown in FIGS. The temperature range is divided into one or more temperature ranges, and the detection output range of the compensation sensor is divided into one or more ranges. The divided roller temperature range and the divided detection range of the compensation sensor are divided. An arithmetic expression for calculating the surface temperature set corresponding to each of the regions defined by the following is stored in advance.
[0045]
The output of the surface temperature calculating means 65 is connected to the control input 641 of the heating control means 64 to control ON / OFF of the power supply to the halogen lamp heater 471a.
[0046]
Reference numeral 6 denotes a control unit that reads a temperature control program and a target control temperature of the heating roller stored in advance in a memory of the storage unit 61, controls the surface temperature calculation unit 65 and the storage unit 61 in accordance with the control program, and It causes the surface temperature calculating means 65 to calculate the surface temperature of the heating roller based on the detection output from the compensation sensor, and compares the calculation result with the target control temperature to perform the processing described below, such as controlling the temperature of the heating roller.
[0047]
The surface temperature calculator 65 controls the amount of heat generated by the halogen lamp heater 471a via the heating controller 64 to heat the heating roller to a predetermined temperature.
[0048]
FIG. 6 is an explanatory diagram of calculating the surface temperature of the heating roller by an arithmetic expression according to the first embodiment of the present invention.
[0049]
FIG. 7 is an explanatory diagram for calculating the surface temperature of the heating roller by an arithmetic expression according to the second and third embodiments of the present invention.
[0050]
FIG. 8 is an explanatory diagram for calculating the surface temperature of the heating roller by an arithmetic expression according to the fourth embodiment of the present invention.
[0051]
FIG. 9 is an explanatory diagram for calculating the surface temperature of the heating roller by an arithmetic expression according to the fifth and sixth embodiments of the present invention.
[0052]
FIG. 10 is a flowchart illustrating the first embodiment of the present invention.
FIG. 11 is a flowchart for explaining the second and fourth embodiments of the present invention.
[0053]
FIG. 12 is a flowchart for explaining the third embodiment of the present invention.
FIG. 13 is a flowchart for explaining the fourth embodiment of the present invention.
[0054]
FIG. 14 is a flowchart for explaining the fifth embodiment of the present invention.
FIG. 15 is a flowchart for explaining the sixth embodiment of the present invention.
[0055]
Hereinafter, the first embodiment will be described with reference to FIGS. 2, 6, and 10. FIG.
In step (1), the detection sensor 472 always detects the surface temperature of the heating roller and the compensation sensor 473 always detects the temperature of the detection sensor, and outputs the detection output to the buffers 621 and 622.
[0056]
The buffers 621 and 622 perform impedance matching between the sensor and the A / D converter, and input the outputs of the buffers to the A / D converter 63, respectively.
[0057]
The detection outputs of the detection sensor and the compensation sensor input to the A / D converter 63 via the buffers 621 and 622 are respectively converted to digital, and the digital output is input to the surface temperature calculation unit 65.
[0058]
Then, the control means 6 causes the surface temperature calculation means 65 to read the digital outputs of the detection sensor and the compensation sensor.
[0059]
In step (2), the control means 6 corresponds to the area 2 defined by the roller temperature range (for example, 140 to 200 ° C.) for normal printing and the detection range of the compensation sensor shown in FIG. The surface temperature calculation means 65 reads a first-order calculation formula (for example, calculation formula 2) for calculating the surface temperature of the heating roller set as above.
Equation 2: Surface temperature = ER _n − (A ₁ × EH _n -A _Two ) / (A _Three × EH _n + A _Four )
ER _n Is the detection sensor output, EH _n Is the compensation sensor output, a ₁ ~ A _Four Is a constant.
[0060]
In step (3), the control means 6 adds the (digitalized) outputs of the detection sensor and the compensation sensor read in step (1), ERn and EHn to the arithmetic expression 2 read in step 2 by the surface temperature calculating means 65. And the calculation means 652 calculates the surface temperature.
[0061]
In step (4), the control means 6 causes the surface temperature calculation means 65 to compare the calculated surface temperature with the target control temperature (for example, 200 ° C.) of the current operation mode read from the storage means 61, and If the value is lower, the process proceeds to step (5). If the value is higher, the process proceeds to step (6).
[0062]
In step (5), the control means 6 causes the control means 653 of the surface temperature calculation means 65 to output a control signal for heating the heating roller 474 to the heating control means 642. In response to this signal, the heating control member 642 turns on electricity to the halogen lamp heater 471a to heat the heating roller 474.
[0063]
In step (6), the control means 6 causes the control means 653 to output a control signal to the heating control means 642 to stop heating the heating roller 474. In response to this signal, the heating control member 642 turns off the power supply to the halogen lamp heater 471a and stops heating the heating roller 474.
[0064]
Next, a second embodiment will be described with reference to FIG. 2, FIG. 7, and FIG.
Step (1) performs the same processing as in the first embodiment.
[0065]
In step (2), the control unit 6 divides the roller temperature range in which the temperature control of the heating roller is to be performed and is divided into two or more temperature ranges shown in FIG. A first-order arithmetic expression (for example, arithmetic expressions 3 and 4) for calculating the surface temperature of the heating roller set corresponding to each of the regions defined by the range and the detection range of the compensation sensor is read into the surface temperature calculating means 65. Let
Equation 3: Surface temperature = ER _n − (B ₁ × EH _n -B _Two ) / (B _Three × EH _n + B _Four )
Equation 4: Surface temperature = ER _n − (C ₁ × EH _n -C _Two ) / (C _Three × EH _n + C _Four )
ER _n Is the detection sensor output, EH _n Is the compensation sensor output, b ₁ ~ C _Four Is a constant.
[0066]
Here, the temperature range in which the temperature control of the heating roller is to be performed (for example, 80 to 200 ° C.) is divided into the range of the roller temperature range (for example, 140 to 200 ° C.) in which the normal printing of the heating roller is performed. The arithmetic expression 3 is set for the area 6 and is set for the area 5 of the heating roller divided into, for example, 139 to 200 ° C.
[0067]
In step (3), the control unit 6 causes the surface temperature calculation unit 65 to compare the control target temperature (for example, 190 ° C.) of the current operation mode with each of the divided roller temperature ranges. (For example, the arithmetic expression 4 in the area 6) is selected by the selecting means 651.
[0068]
In step (4), the control means 6 causes the surface temperature calculating means 65 to convert the arithmetic expression (for example, arithmetic expression 4) selected in step (3) into the digital form of the detection sensor and the compensation sensor read in step (1). The output, ERn and EHn are applied, and the calculation means 652 calculates the surface temperature.
[0069]
After step (5), the same processing as steps (4) to (6) of the first embodiment is performed.
[0070]
Next, a third embodiment will be described with reference to FIGS. 2, 7, and 12. FIG.
Steps (1) and (2) perform the same processing as in the second embodiment.
[0071]
In step (3), the control means 6 reads the two primary arithmetic expressions (for example, arithmetic expressions 3 and 4 described above) read in step (2) into the surface temperature calculating means 65 in step (1). The (digitalized) outputs ERn and EHn of the detection sensor and the compensation sensor are applied, and the calculation means 652 calculates the surface temperature.
[0072]
In step (4), the control unit 6 causes the comparison and judgment unit 654 to compare the operation results of the two types of operation expressions (for example, operation expressions 3 and 4) calculated in step (3), and compares the smallest operation result with the final surface Let the temperature.
[0073]
After step (5), the same processing as in steps (4) to (6) of the first embodiment is performed.
[0074]
Next, a fourth embodiment will be described with reference to FIGS.
Step (1) performs the same processing as in the first embodiment.
[0075]
In step (2), the control means 6 determines that the detection output range of the compensation sensor is divided into two or more ranges shown in FIG. Is read by the surface temperature calculating means 65 to calculate the first-order arithmetic expression (for example, arithmetic expressions 5 and 6) for calculating the surface temperature of the heating roller set corresponding to each of the regions defined by the detection ranges.
Equation 5: Surface temperature = ER _n − (D ₁ × EH _n -D _Two ) / (D _Three × EH _n + D _Four )
Equation 6: Surface temperature = ER _n − (E ₁ × EH _n -E _Two ) / (E _Three × EH _n + E _Four )
ER _n Is the detection sensor output, EH _n Is the compensation sensor output, d ₁ ~ E _Four Is a constant.
[0076]
Here, with respect to the roller temperature range (for example, 140 to 200 ° C.) in which the normal printing of the heating roller shown in FIG. 8 is performed, the arithmetic expression 5 sets the compensation sensor temperature range to, for example, a range of 0 to 70 ° C. The arithmetic expression 6 is set for the divided combined region 7 in the same manner, for example, for the combined region 8 divided into a range of 71 to 150 ° C.
[0077]
In step (3), the control means 6 causes the surface temperature calculating means 65 to compare the compensation sensor temperature corresponding to the detection output of the compensation sensor read in step (1) with each of the divided compensation temperature ranges. The calculating unit 651 selects an arithmetic expression in the region including the temperature (for example, the arithmetic expression 6 in the region 8).
[0078]
In step (4), the control means 6 causes the surface temperature calculating means 65 to convert the arithmetic expression (for example, arithmetic expression 6) selected in step (3) into a digital form of the detection sensor and the compensation sensor read in step (1). Then, the output, ERn and EHn are applied, and the calculation means 652 calculates the surface temperature.
[0079]
After step (5), the same processing as steps (4) to (6) of the first embodiment is performed.
[0080]
Next, a fifth embodiment will be described with reference to FIGS. 2, 9, and 14. FIG.
Step (1) performs the same processing as in the first embodiment.
[0081]
In step (2), the control unit 6 divides the roller temperature range for controlling the temperature of the heating roller into two or more temperature ranges shown in FIG. The detection output range is divided into two or more ranges, and the surface temperature of the heating roller set corresponding to each of the regions defined by the divided roller temperature range and the divided detection range of the compensation sensor is calculated. The first-order arithmetic expression (for example, arithmetic expressions 7 to 10) is read by the surface temperature calculating means 65.
Equation 7: Surface temperature = ER _n − (F ₁ × EH _n −f _Two ) / (F _Three × EH _n + F _Four )
Equation 8: Surface temperature = ER _n − (G ₁ × EH _n -G _Two ) / (G _Three × EH _n + G _Four )
Equation 9: Surface temperature = ER _n -(H ₁ × EH _n -H _Two ) / (H _Three × EH _n + H _Four )
Equation 10: Surface temperature = ER _n − (I ₁ × EH _n −i _Two ) / (I _Three × EH _n + I _Four )
ER _n Is the detection sensor output, EH _n Is the compensation sensor output, f ₁ ~ I _Four Is a constant.
[0082]
Here, the arithmetic expressions 7 and 9 are obtained by dividing the compensation temperature range (for example, 0 to 150 ° C.) into, for example, a range of 0 to 70 ° C., and performing the temperature control of the heating roller (for example, 80 to 200 ° C.). ) Are set for the roller temperature range (for example, 140 to 200 ° C.) for normal printing of the heating roller and the combination areas 9 and 11 divided into 80 to 139 ° C.
[0083]
The arithmetic expressions 8 and 10 are set for the combination areas 10 and 12 based on the same idea.
[0084]
In step (3), the control means 6 causes the surface temperature calculation means 65 to compare the compensation sensor temperature corresponding to the detection output of the compensation sensor read in step (1) with each of the divided compensation temperature ranges. The calculating unit 651 selects an arithmetic expression (for example, arithmetic expressions 8 and 10 for the regions 10 and 12) of the region including the temperature.
[0085]
Next, the control target temperature in the current operation mode (for example, 190 ° C.) is compared with each of the divided roller temperature ranges, and the calculation formula (for example, the calculation formula 10 in the region 12) of the region including the control target temperature is selected by the selection unit 651. Let it.
[0086]
In step (4), the control means 6 causes the surface temperature calculation means 65 to convert the arithmetic expression (for example, arithmetic expression 10) selected in step (3) into the digital form of the detection sensor and the compensation sensor read in step (1). The output, ERn and EHn are applied, and the calculation means 652 calculates the surface temperature.
[0087]
After step (5), the same processing as steps (4) to (6) of the first embodiment is performed.
[0088]
Next, a control method according to the sixth embodiment will be described with reference to FIG. 2, FIG. 9, and FIG.
[0089]
Steps (1) and (2) perform the same processing as in the fifth embodiment.
In step (3), the control means 6 causes the surface temperature calculation means 65 to compare the compensation sensor temperature corresponding to the detection output of the compensation sensor read in step (1) with each of the divided compensation temperature ranges. (For example, the arithmetic expressions 8 and 10 of the regions 10 and 12 described above) are selected by the selecting unit 651.
[0090]
In step (4), the control unit 6 causes the surface temperature calculation unit 65 to detect the detection sensor and the compensation sensor read in step (1) for the two arithmetic expressions (for example, arithmetic expressions 8 and 10) selected in step (3). (Digitized) outputs ERn and EHn, and the calculation means 652 calculates the surface temperature.
[0091]
In step (5), the control means 6 causes the surface temperature calculation means 65 to compare the calculation results of the two calculation expressions (arithmetic expressions 8 and 10) calculated in step (4) by the comparison determination means 654, Let the result be the surface temperature.
[0092]
After step (6), the same processing as in steps (4) to (6) of the first embodiment is performed.
[0093]
As described above, the case where the compensation temperature range and the roller temperature range are each divided into 1 or 2 and the arithmetic expression is set for a region in which both are combined has been described for easier understanding. In order to make it possible, each is divided into 3 or more with a predetermined width (preferably 10 or less so that the number of man-hours for calculation setting does not become too large and the calculation speed does not decrease). , A predetermined arithmetic expression is set for each, and the surface temperature can be calculated based on the above idea.
[0094]
Further, for the sake of simplicity of explanation, the temperature range of the compensation sensor is set to the range of 0 to 150 ° C., and this range is divided into approximately two equal parts to set the division range. As a compensation sensor temperature range (for example, 40 to 150 ° C.) corresponding to a temperature range (for example, 80 to 220 ° C.), a compensation sensor temperature range corresponding to a roller temperature range (for example, 160 to 200 ° C.) in which normal printing is performed for this range. And other ranges.
[0095]
According to the embodiments described above, the roller temperature detection range or the compensation temperature detection range is divided into small areas, and the surface temperature of the heating roller is calculated for each of the divided areas based on the detection values of the detection sensor and the compensation sensor. A calculation formula is set, the detection sensor output and the compensation sensor output are applied to the calculation formula to calculate the surface temperature, and the temperature of the heating roller is controlled based on the calculated value. Provided is an image forming apparatus capable of accurately and quickly detecting the surface temperature of a heating roller without requiring a large storage capacity for data storage, and controlling without causing a fixing abnormality such as breakage of a heating roller or offset. It is possible to do.
[0096]
【The invention's effect】
According to the present invention, it is possible to accurately and quickly detect the surface temperature of a heating roller without requiring a large number of man-hours for creating data and a large storage capacity for storing data, and to damage or offset a heating roller. And an image forming apparatus that can be controlled without causing a fixing abnormality such as the above. "
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a control block diagram according to the embodiment of the present invention.
FIG. 3 is a graph of calculation results of a plurality of equations.
FIG. 4 is a data table diagram for calculating a surface temperature based on a detection output and a correction output.
FIG. 5 is an explanatory diagram for calculating a surface temperature by a conventional single arithmetic expression.
FIG. 6 is an explanatory diagram of calculating a surface temperature of a heating roller by an arithmetic expression according to the first embodiment of this invention.
FIG. 7 is an explanatory diagram for calculating a surface temperature of a heating roller by an arithmetic expression according to the second and third embodiments of the present invention.
FIG. 8 is an explanatory diagram of calculating a surface temperature of a heating roller by an arithmetic expression according to the fourth embodiment of the present invention.
FIG. 9 is an explanatory diagram for calculating a surface temperature of a heating roller by an arithmetic expression according to the fifth and sixth embodiments of the present invention.
FIG. 10 is a flowchart illustrating a first embodiment of the present invention.
FIG. 11 is a flowchart illustrating a second embodiment of the present invention.
FIG. 12 is a flowchart illustrating a third embodiment of the present invention.
FIG. 13 is a flowchart illustrating a fourth embodiment of the present invention.
FIG. 14 is a flowchart illustrating a fifth embodiment of the present invention.
FIG. 15 is a flowchart illustrating a sixth embodiment of the present invention.
[Explanation of symbols]
6,653 control means
47 fixing means
61 storage means
63 A / D converter
64 Heating control means
65 Surface temperature calculation means
471a Heat source (halogen lamp heater)
472 detection sensor
473 Compensation sensor
474 heating roller
651 Selection means
652 arithmetic means
654 Comparison judgment means

Claims (10)

A heating roller heated by a heating source, a detection sensor that detects the surface temperature of the heating roller in a non-contact manner, and an image forming apparatus including a compensation sensor that detects the temperature of the detection sensor,
A storage unit storing an arithmetic expression set corresponding to an area determined by a roller temperature range in which normal printing is performed, and the arithmetic expression of the heating roller in the arithmetic expression based on detection outputs of the detection sensor and the compensation sensor. An image forming apparatus comprising: an arithmetic unit that calculates a surface temperature; and a control unit that controls energization of the heating source based on a calculation result and a target control temperature. A heating roller heated by a heating source, a detection sensor that detects the surface temperature of the heating roller in a non-contact manner, and an image forming apparatus including a compensation sensor that detects the temperature of the detection sensor,
The roller temperature range for controlling the temperature of the heating roller is divided into one or more temperature ranges, and the detection output range of the compensation sensor is divided into one or more ranges. A storage unit that stores an arithmetic expression set corresponding to each of the regions defined by the range and the divided detection range of the compensation sensor, and a storage unit that stores the target control temperature and the detection temperature of the compensation sensor. Selecting means for selecting the calculated formula, calculating means for calculating the surface temperature of the heating roller with the selected formula based on the detection outputs of the detection sensor and the compensation sensor, and calculating the calculated result and the target control temperature. An image forming apparatus comprising: a control unit configured to control power supply to the heating source based on the control signal. A heating roller heated by a heating source, a detection sensor that detects the surface temperature of the heating roller in a non-contact manner, and an image forming apparatus including a compensation sensor that detects the temperature of the detection sensor,
The roller temperature range for controlling the temperature of the heating roller is divided into two or more temperature ranges, and the detection output range of the compensation sensor is divided into one or two or more ranges. Storage means for storing an arithmetic expression set corresponding to each of the areas defined by the divided detection ranges of the compensation sensor;
Based on the detection outputs of the detection sensor and the compensation sensor, calculating means for calculating the surface temperature of the heating roller with the plurality of set arithmetic expressions,
Comparing and judging means for setting a smaller value of the plurality of calculation results as a final surface temperature,
An image forming apparatus comprising: control means for controlling power supply to the heating source based on the final surface temperature and the target control temperature. 5. The method according to claim 1, wherein the roller temperature range in which the temperature control of the heating roller is to be performed is divided into one or two or more temperature ranges, wherein one of the roller temperature ranges is a roller temperature range in which normal printing is performed. The image forming apparatus according to any one of claims 2 to 3. The image forming apparatus according to claim 1, wherein the arithmetic expression is a first-order arithmetic expression. The detection output range of the compensation sensor is a detection output range of the compensation sensor corresponding to a temperature range of the detection sensor for performing temperature control of the heating roller. The image forming apparatus according to any one of the preceding claims. A pre-stored calculation that reads the detection output of the detection roller that detects the temperature of the heating roller and the compensation sensor that detects the temperature of the detection sensor, and calculates the surface temperature of the heating roller set in the roller temperature range where normal printing is performed. The formula is read, the calculation formula is calculated according to the detection output of the detection sensor and the compensation sensor, the calculation result is set as the surface temperature of the heating roller, and the surface temperature is compared with a target temperature. A method for controlling an image forming apparatus, comprising: performing temperature control. It reads the detection output of the detection roller that detects the temperature of the heating roller and the compensation sensor that detects the temperature of the detection sensor, and calculates the surface temperature of the heating roller set within the temperature range in which the temperature control of the heating roller is to be performed. A plurality of pre-stored arithmetic expressions are read, an arithmetic expression corresponding to the target control temperature and the detection value of the compensation sensor is selected from the read arithmetic expressions, and selected according to the detection outputs of the detection sensor and the compensation sensor. A control method for an image forming apparatus, comprising: calculating a calculation expression; setting a calculation result as a surface temperature of the heating roller; comparing the surface temperature with a target temperature; and controlling a temperature of the heating roller based on the result. It reads the detection output of the detection roller that detects the temperature of the heating roller and the compensation sensor that detects the temperature of the detection sensor, and calculates the surface temperature of the heating roller set within the temperature range in which the temperature control of the heating roller is to be performed. A plurality of pre-stored arithmetic expressions are read, a plurality of arithmetic expressions corresponding to the detection values of the compensation sensor are selected from the read arithmetic expressions, and the arithmetic expressions selected according to the detection sensor and the detection output of the compensation sensor are calculated. Controlling the temperature of the heating roller based on the result of comparing the surface temperature with the target temperature, and performing the temperature control of the heating roller based on the result. Method. The method according to claim 7, wherein the arithmetic expression is a first-order arithmetic expression.

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