JP2018017906A - Image heating device, and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that can achieve the most appropriate through-put even when an end part of a recording material is present at a position where temperature detection means may not directly detect a heating block in a multi-division heater having a plurality of heating blocks in a longitudinal direction.SOLUTION: An image heating device comprises temperature prediction means 404 that predicts a temperature of a non-passing part through which a recording material does not pass in a prediction target area serving as a heating area including a passing part through which the recording material passes and the non-passing part and serving a heating area where the non-passing part does not overlap on a temperature detection position of temperature detection means on the basis of a detection temperature of the non-passing part in a prediction unnecessary area serving as the heating area where the non-passing part overlaps on the temperature detection position, of a plurality of heating areas to be formed by a plurality of heating elements arrayed in a longitudinal direction orthogonal to a conveyance direction of the recording material in a heater 200. Conveyance control means 405 is configured to adjust a conveyance interval upon successively conveying a plurality of recording materials on the basis of a temperature predicted by the temperature prediction means 404.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer using an electrophotographic system or an electrostatic recording system. The present invention also relates to an image heating apparatus such as a fixing device mounted on an image forming apparatus and a gloss applying apparatus that improves the glossiness of a toner image by reheating a toner image fixed on a recording material.

  As an image heating apparatus, there is an apparatus having a fixing film, a heater that contacts an inner surface of the fixing film, and a roller that forms a nip portion together with the heater via the fixing film. In an image forming apparatus in which this image heating device is mounted as a fixing device, a recording material having a size smaller than the maximum sheet passing width in a direction orthogonal to the recording material conveyance direction (hereinafter referred to as a longitudinal direction) is continuously formed. (Hereinafter referred to as continuous printing), so-called non-sheet passing portion temperature rise occurs. That is, this is a phenomenon in which the temperature of each part gradually increases in a region where the recording material does not pass in the longitudinal direction of the nip portion (hereinafter referred to as a non-sheet passing portion). As an image heating apparatus, it is necessary that the temperature of the non-sheet passing portion does not exceed the heat resistance temperature of each member in the apparatus. For this reason, a method of suppressing the temperature rise of the non-sheet passing portion by reducing the throughput of continuous printing (number of sheets that can be printed per minute) (hereinafter referred to as throughput reduction) is often used.

  On the other hand, Patent Document 1 discloses one technique for suppressing the temperature increase of the non-sheet passing portion without reducing the throughput as much as possible. The technique is a technique in which a heat generating block consisting of a pair of a conductor and a heat generating element is divided at a position corresponding to the recording material size in the heater longitudinal direction, and the power supplied to each divided heat generating block is controlled independently. . For example, as shown in FIG. 2, the heat generating block is divided into five, and the power supplied to the heat generating blocks 202-1, 202-2, 202-3, 202-4, 202-5 is independently controlled. In this configuration, when printing a recording material (for example, A5 paper) having a longitudinal width of 157 mm or less of the central heat generating block 202-3, by not supplying power to the heat generating block through which the recording material does not pass, Non-sheet passing portion temperature rise can be suppressed.

JP 2014-59508 A

  Even with such a heater in which the heat generating blocks are divided, when a recording material (for example, B6 paper) having a size in which the divided position of each heat generating block does not coincide with the position of the paper edge is printed, the non-sheet passing portion generates heat. Temperature may rise. Therefore, there is a possibility that the throughput is reduced depending on the size of the recording material. In recent years, since further improvement in the first printout time (hereinafter referred to as FPOT) has been demanded, the image heating apparatus itself tends to be made smaller in order to suppress the heat capacity of the image heating apparatus. For this reason, there is a case where temperature detection means (for example, thermistor) cannot be arranged in all the heat generation blocks of the heater divided into the heat generation blocks.

In such a case, if the temperature rise of the non-sheet passing portion as described above occurs in the heat generating block without the temperature detecting means, the temperature rise of the non-sheet passing portion cannot be directly detected. Therefore, it becomes difficult to reduce the throughput according to the temperature rise of the non-sheet passing portion. For example, the temperature reduction of the non-sheet passing portion is predicted by predicting the temperature rise of the non-sheet passing portion from the number of sheets to be passed. When throughput reduction is performed by predicting the temperature rise in the non-sheet-passing area based on the number of sheets passed, etc., increase the throughput reduction amount in consideration of heater resistance variations, power supply voltage variations, etc. Need arises.

  The purpose of the present invention is to achieve optimum throughput even when the edge of the recording material is located in a heat generating block that cannot be directly detected by the temperature detecting means in a multi-split heater having a plurality of heat generating blocks in the longitudinal direction. Is to provide technology that can be.

In order to achieve the above object, the image heating apparatus of the present invention comprises:
A heater having a plurality of heating elements arranged in a longitudinal direction perpendicular to the conveyance direction of the recording material;
A plurality of temperature detection means arranged in the longitudinal direction and detecting the temperature of a region heated by the heat of the heater;
Power control means for individually controlling the power supplied to the plurality of heating elements based on the temperature detected by the temperature detection means;
A conveyance control means for adjusting a conveyance interval when a plurality of recording materials are continuously conveyed to a region heated by the heat of the heater;
With
In an image heating apparatus for heating an image formed on a recording material by the heat of the heater,
Among the plurality of heating regions formed by the plurality of heating elements, the heating region includes a passing part through which the recording material passes and a non-passing part through which the recording material does not pass, and the non-passing part and the temperature detecting means are arranged. The temperature of the non-passing portion in the prediction target region that is a heating region that does not overlap with the temperature detection position is the detected temperature of the non-passing portion in the prediction unnecessary region that is the heating region where the non-passing portion and the temperature detection position overlap. Based on temperature prediction means for predicting,
The conveyance control unit adjusts the conveyance interval based on the temperature predicted by the temperature prediction unit.
In order to achieve the above object, the image forming apparatus of the present invention includes:
An image forming unit for forming an image on a recording material;
A fixing unit for fixing the image formed on the recording material to the recording material;
In an image forming apparatus having
The fixing unit is the image heating device.

  According to the present invention, in a multi-division heater having a plurality of heat generating blocks in the longitudinal direction, even when the end of the recording material is located on the heat generating block that cannot be directly detected by the temperature detecting means, the optimum throughput is realized. can do.

1 is a cross-sectional view illustrating an example of an image forming apparatus according to an embodiment of the present invention. The block diagram of the heater 200 in Example 1,2. The heater control circuit diagram in Examples 1 and 2. FIG. The control system block diagram in Example 1,2. 6 is a flowchart in the first and second embodiments. The positional relationship diagram of the heater 200 and the recording paper when the B6 paper is passed. The positional relationship diagram of the heater 200 and the recording paper when the square type 6 envelope is passed.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

[Example 1]
FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. Examples of the image forming apparatus to which the present invention can be applied include a copying machine, a printer, a recording machine, a facsimile, and the like using an electrophotographic system, an electrostatic recording system, and the like. Here, a case where the present invention is applied to a laser printer will be described. The present invention is not limited to a fixing device (fixing unit) mounted in an image forming apparatus, but also to a gloss applying device used as an external device separate from the image forming apparatus and connected to the image forming apparatus. Is also applicable. In this case, various operations of the gloss imparting device may be configured to be controlled by a control unit provided in the gloss imparting device based on a command received from a control unit or the like of an external image forming apparatus. That is, in the present invention, the control unit that controls various operations of the image heating apparatus may be a part of the configuration of the image heating apparatus, or is included in the image heating apparatus like the control unit of the image forming apparatus. There can be no external configuration.

  In FIG. 1, reference numeral 122 denotes a photosensitive drum made of an organic photosensitive member or an amorphous silicon photosensitive member, which is rotationally driven at a predetermined peripheral speed (process speed) in the clockwise direction. The photosensitive drum 122 and the charging roller 123 uniformly charge the peripheral surface to a predetermined polarity and potential. Then, the laser beam output from the laser optical box 108 is deflected and irradiated on the charging surface by the laser beam reflecting mirror 107, and scanning exposure is performed, and an electrostatic latent image corresponding to the image information is formed. It is formed. The laser light output from the laser optical box 108 is modulated (ON) corresponding to the time-series electric digital pixel signal of the target image information input from an image signal generator (not shown) such as an image reading device or a computer. / Off conversion). The scanning exposure start timing in the sub-scanning direction is notified from the image forming apparatus 100 to the image signal generating apparatus by a sub-scanning direction synchronization signal. The electrostatic latent image thus formed corresponding to the target image is developed by the developing roller 121 carrying the developer (toner), and a developer image (toner image) is formed on the photosensitive drum 122. .

  Next, one sheet of recording paper P as a recording material is fed from a paper feed cassette by a paper feed roller 102, transported by a transport roller 103 and a registration roller 104, and a transfer nip formed by a photosensitive drum 122 and a transfer roller 106. Sent to the department. In the transfer nip portion, a voltage is applied to the transfer roller 106, whereby a charge having a polarity opposite to that of the toner is supplied from the back surface of the recording paper P, and the toner image on the photosensitive drum 122 is transferred to the recording paper P. As described above, the configuration until the toner image is formed on the recording paper corresponds to the image forming unit in the present invention. The recording paper P to which the toner image has been transferred is separated from the photosensitive drum 122 and sent to the fixing device 130. The toner image is heat-fixed at the nip formed by the heater 200 in contact with the inner surface of the cylindrical fixing film (also referred to as an endless belt) 132 and the fixing film 132 and the pressure roller 133. The recording paper P that has undergone thermal fixing is conveyed by a fixing paper discharge roller 110 and an FD roller 111 and discharged to an FD tray 112.

  Each roller of the image forming apparatus 100 is rotationally driven by a motor (not shown). The motor (not shown) and the paper feed roller 102 are connected via a paper feed clutch 140 (not shown). When the recording paper P is fed from the paper feed cassette, the paper feed clutch 140 is turned on for a predetermined time. The paper feed rollers 102 are driven to rotate.

FIG. 2 is a configuration diagram (viewed from the back side) of the heater 200 in the present embodiment. The heater 200 is heated by a heating resistor as a heating element provided on a ceramic substrate 204. Thermistors TH1, TH2, and TH3 are in contact with the sheet passing area of the image forming apparatus 100 on the back surface side of the substrate 204 as a plurality of temperature detection elements arranged in the longitudinal direction. A safety element (not shown) such as a thermo switch or a thermal fuse that is operated by the abnormal heat generation of the heater 200 and cuts off the power supplied to the heater 200 is also in contact with the back side of the substrate 204.

  A plurality of heat generating blocks are provided in the longitudinal direction of the heater 200 on the substrate 204 on the back surface of the heater 200. Each heating block includes a first conductor 201 (201a, 201b), a second conductor 203 (203-1 to 203-5), and a heating resistor 202 (202a-1 to 202a-5, 202b-1 to 202b-). 5). The heat generation block corresponds to a heating region where each heat generation resistor in the plurality of heat generation resistors provided on the substrate 204 is heated. As an example, the heater 200 of this embodiment has a total of five heat generating blocks at the center and both ends in the longitudinal direction of the heater 200. The first heat generating block 202-1 is composed of heat generating resistors 202a-1 and 202b-1 which are formed symmetrically in the short direction of the heater 200 (the direction orthogonal to the longitudinal direction). Similarly, the second heat generating block 202-2 includes heat generating resistors 202a-2 and 202b-2, and the third heat generating block 202-3 includes heat generating resistors 202a-3 and 202b-3. ing. The fourth heat generating block 202-4 is composed of heat generating resistors 202a-4 and 202b-4, and the fifth heat generating block 202-5 is composed of heat generating resistors 202a-5 and 202b-5. Yes.

  The first conductor 201 provided along the longitudinal direction of the heater 200 includes a pair of conductors 201a and 201b. The conductor 201a is used to connect to a heating resistor (202a-1, 202a-2, 202a-3, 202a-4, 202a-5) arranged on the upstream side of the heater 200 in the short direction. Further, the conductor 201b is used to connect to a heating resistor (202b-1, 202b-2, 202b-3, 202b-4, 202b-5) disposed on the downstream side of the heater 200 in the short direction. It is done.

  The second conductor 203 provided along the longitudinal direction of the heater 200 is divided into five conductors 203-1, 203-2, 203-3, 203-4, and 203-5 in the longitudinal direction. Yes.

  The electrodes E1, E2, E3, E4, E5, E6-1, and E6-2 are used to connect to electrical contacts used to supply power from the control circuit 300 of the heater 200 described later. The electrode E1 is used to supply power to the heat generating block 202-1 through the conductor 203-1. Similarly, the electrode E2 is an electrode used to supply power to the heat generating block 202-2 via the conductor 203-2, and the electrode E3 is connected to the heat generating block 202-3 via the conductor 203-3. It is an electrode used for supplying power. The electrode E4 is an electrode used to supply power to the heat generating block 202-4 via the conductor 203-4, and the electrode E5 supplies power to the heat generating block 202-5 via the conductor 203-5. It is an electrode used for this. The electrodes E6-1 and E6-2 are electrodes used to connect to common electric contacts used to supply power to the five heat generating blocks 202-1 to 202-5 via the conductor 201a and the conductor 201b. It is.

  As described in Japanese Patent Application Laid-Open No. 2011-151003, it is known that the resistance value of the conductor affects the heat generation distribution in the longitudinal direction of the heater 200. The heater 200 according to the present embodiment has an electrode E6- so that a heat generation distribution symmetrical to the longitudinal direction of the heater 200 can be obtained even under the influence of the electrical resistance of the conductors 203-1 to 203-5, 201a, 201b. 1 and E6-2 are provided at both ends of the heater 200 in the longitudinal direction.

On the back surface of the heater 200, a surface protective layer (not shown) is formed as a second layer on the first layer on which the above-described conductor and heating resistor are formed. The surface protective layer is formed except for the portions of the electrodes E1 to E5, E6-1, and E6-2, and has a configuration in which an electrical contact can be connected to each electrode from the back side of the heater 200. In this embodiment, the ratio of the power supplied to at least one heat generating block among the plurality of heat generating blocks and the power supplied to the other heat generating blocks can be obtained by adopting a configuration in which power can be supplied from the back side of the heater 200. The controllable configuration. The electrical contacts of the electrodes E1 to E5, E6-1, and E6-2 are electrically connected to the electrode portions by contact pressure, welding, and the like, respectively, and will be described later via a conductive material such as a cable or a thin metal plate. The control circuit 300 of the heater 200 is connected.

  Power control to the heater 200 is performed based on the output of the thermistor TH2 provided near the center of the sheet passing portion. The thermistor TH1 detects the end temperature of the heat generation area of the heat generation block 202-1. The thermistor TH3 detects the end temperature of the heat generation area of the heat generation block 202-5.

  FIG. 3 is a schematic diagram of the heater control circuit 300 in the present embodiment. Reference numeral 301 denotes a commercial AC power source connected to the image forming apparatus 100. The power control of the heater 200 is performed by energizing / cutting off the triac 351, the triac 352, and the triac 353. Electric power is supplied to the heater 200 through the electrodes E1 to E6.

The zero-cross detection unit 330 is a circuit that detects a zero-cross of the AC power supply 301 and outputs a ZEROX signal to the CPU 320. The ZEROX signal is used for heater control. As an example of a zero cross circuit, a method described in JP 2011-18027 A can be used.
The relay 340 is used as means for shutting off the power supply to the heater 200 when the thermistors TH1 to TH3 detect an excessive temperature rise of the heater 200 due to a failure or the like.

The triac 351 is connected to the CPU 320 via a phototriac coupler (not shown), and operates according to the FUSER1 signal from the CPU 320. When the triac 351 is energized, power is supplied to the heat generating block 202-3.
The triac 352 is connected to the CPU 320 via a phototriac coupler (not shown), and operates in accordance with the FUSER2 signal from the CPU 320. When the triac 352 is energized, power is supplied to the heat generating block 202-2 and the heat generating block 202-4.
The triac 353 is connected to the CPU 320 via a phototriac coupler (not shown), and operates in accordance with the FUSER3 signal from the CPU 320. When the triac 353 is energized, power is supplied to the heat generating block 202-1 and the heat generating block 202-5.

  The temperature detected by the thermistor TH2 is detected by the CPU 320 as a TH2 signal as a partial pressure with a resistor (not shown). The thermistor TH1 and thermistor TH3 are also detected by the CPU 320 in the same manner. In the internal processing of the CPU 320, based on the detected temperature of the thermistor TH2 and the set temperature of the heater 200, for example, the power to be supplied is calculated by PI control. Furthermore, the phase angle (phase control) and the wave number (wave number control) corresponding to the supplied power are converted into control levels, and the triac 351, the triac 352, and the triac 353 are controlled according to the control conditions.

  FIG. 4 is a block diagram of a control system in the image forming apparatus according to the present embodiment. The image forming control unit 400 includes a CPU 320 that controls the entire image forming apparatus as a control unit, a ROM that stores a control program (not shown), a RAM that stores data, a gate element, and the like. The image formation control unit 400 mainly includes a sheet width information acquisition unit 401, a power control unit 402, a fixing temperature control unit 403, a non-sheet passing portion temperature prediction unit 404, a sheet conveyance control unit 405, and the like.

The paper width information acquisition unit 401 acquires recording paper width information from the controller device 450.
The power control unit 402 individually controls the input power to each heat generating block of the heater 200 via the heater control circuit 300 based on information from the sheet width information acquisition unit 401, the fixing temperature control unit 403, and the like. The power control means 402 can input different amounts of power to each heat generating block.
The fixing temperature control unit 403 notifies the power control unit of information for maintaining the heater 200 at a desired temperature based on information from the thermistor TH2.
The non-sheet-passing portion temperature predicting unit 404 predicts the temperature of the non-sheet-passing portion based on information from the power control unit 402, the thermistors TH1, TH2, and the like.
The sheet conveyance control unit 405 determines the conveyance of the recording sheet, specifically, the conveyance timing or when conveying a plurality of recording sheets from the information such as the top sensor 105 and the non-sheet passing portion temperature prediction unit 404. It controls the adjustment of the conveyance interval.

  The controller device 450 includes a CPU that controls the entire controller device, a ROM that stores a control program, a RAM that stores data, a gate element, and the like. The controller device 450 is connected to a device (not shown) such as an image reading device or a computer, and an image forming device via communication means. The controller device 450 generates region information of an image formed on the recording material based on information from an image reading device or a computer, and transmits the information to the image forming device control unit 400.

  A specific process performed by the image forming apparatus control unit 400 in this embodiment will be described with reference to the flowchart of FIG. When there is a print instruction from the controller device 450 to the image forming apparatus 100, the processing shown in the flowchart of FIG. 5 is started.

  In step 1, the image forming apparatus control unit 400 confirms the sheet width information designated by the controller device 450 through the sheet width information acquisition unit 401, and proceeds to step 2. The minimum unit of the paper width information acquired in this embodiment is 0.1 mm. In this embodiment, the sheet width information is acquired from the controller device 450. However, a sheet width detection unit is provided on the paper feed port of the image forming apparatus 100 or on the conveyance path, and the image forming apparatus control unit 400 performs the sheet width detection. May be detected.

In step 2, the power control mode of each heat generating block of the heater 200 is selected from the paper width information acquired in step 1. Table 1 shows the relationship between the paper width information and the power control mode, and the relationship between the paper width and whether or not the non-sheet passing portion temperature prediction is performed.
[Table 1]

The power control mode described in Table 1 will be described.
Type A refers to power for maintaining the toner image at a temperature at which the toner image is thermally fixed on the recording paper (hereinafter referred to as fixing maintenance power) in the heat generation blocks 202-1, 202-2, 202-3, 202-4, and 202-5. It is a power control mode in which the input is called.

Type B is a power mode in which fixing maintenance power is input only to the central heat generation block 202-3. The heat generation blocks 202-1, 202-2, 202-4, 202-5 other than the heat generation block 202-3 are supplied with electric power (hereinafter referred to as the power necessary for maintaining the temperature necessary for the fixing film 132 to slide). This is a power control mode in which the sliding maintenance power is called. Note that the temperature required for the fixing film 132 to slide is lower than the temperature at which the toner image is thermally fixed on the recording paper. For example, when the paper width is 148.0 mm, a non-sheet passing region of 4.5 mm is formed at both ends of the heat generation block 202-3. Since the non-sheet passing area is narrow and the temperature of the adjacent heat generating blocks 202-2 and 202-4 is maintained lower than that of the heat generating block 202-3, it is not necessary to reduce the throughput by increasing the temperature of the non-sheet passing portion. In this embodiment, the determination that the heat generation block 202-3 is not the preheating target area is 4.5 mm in the length in the longitudinal direction of the non-sheet passing portion. Is appropriately set depending on the apparatus configuration, the type of paper, and the like.

Type C is a power control in which fixing maintenance power is supplied to the heat generation blocks 202-2, 202-3, and 202-4, and sliding maintenance power is supplied to the heat generation blocks 202-1 and 202-5. Mode. Note that the temperature required for the fixing film 132 to slide is lower than the temperature at which the toner image is thermally fixed on the recording paper. For example, when the paper width is 182.0 mm, 4.0 mm non-sheet passing areas are formed at both ends of the heat generating blocks 202-2 and 202-4. Since the non-sheet passing area is narrow and the temperatures of the heat generating blocks 202-1 and 202-5 are kept lower than those of the heat generating blocks 202-2 and 202-3, it is not necessary to reduce the throughput due to the temperature increase of the non-sheet passing portion.
The non-sheet passing portion temperature prediction described in Table 1 will be described later.

  In step 3, preparations necessary for image formation, specifically, activation of each motor, charging, application of a developing bias, preparation for laser scanning exposure, and fixing control are started. Regarding fixing control, power control is performed according to the power mode of each heat generating block determined in step 2. Then, when each preparation is completed, it progresses to step 4.

  In step 4, the paper feed clutch 140 is connected to feed the recording paper P from the paper feed cassette, and in step 5, the process waits until the top sensor 105 detects the leading edge of the recording paper P, and then goes to step 6. move on. In step 6, the process waits for the time during which the recording paper P is conveyed from the top sensor 105 to the fixing unit and proceeds to step 7.

  In Steps 7 and 8, the thermistors TH1 and TH3 are monitored until the trailing edge of the recording paper P passes through the fixing device 130 as a fixing unit, and the maximum value is stored. In the present embodiment, the maximum value is stored, but an average value while the recording paper P passes through the fixing device 130 may be stored. Whether or not the trailing edge of the recording sheet P has passed through the fixing device 130 is determined by the time during which the recording sheet P is conveyed from the top sensor 105 to the fixing unit after the top sensor 105 detects the trailing edge of the recording sheet P. Can be determined by whether or not.

  In step 9, it is determined whether or not to predict the non-sheet passing portion temperature from the sheet width information acquired in step 1. Specifically, in the case of a paper width described in the non-sheet-passing portion temperature prediction column described in Table 1, the non-sheet-passing portion temperature is predicted based on the temperature stored in step 7.

With reference to FIG. 6, the non-sheet-passing portion temperature prediction will be described by taking as an example a B6 sheet (paper width 128 mm) that is a sheet width for which the non-sheet-passing portion temperature prediction is performed. FIG. 6 shows the positional relationship between the heater 200 and the recording paper when the B6 paper is passed. When passing B6 paper, at least the heat generation block (heat generation block 202-3) through which the B6 paper passes must be maintained at a temperature for heat fixing. The heat generation block 202-3 is a heating region including a paper passing portion (passing portion) through which the recording paper passes and a non-paper passing portion (non-passing portion) that does not pass, and is a non-paper passing portion in FIG. In -1, A-2, the non-sheet passing portion temperature rise occurs. In areas A-1 and A-2,
Since the thermistor is not arranged, that is, does not overlap with the temperature detection position by the thermistor, the temperature in this region cannot be directly detected. Therefore, the heat generation block 202-3 is a prediction target region among the plurality of heating regions.

  Here, since the width of the B6 sheet is 128.0 mm, from Table 1, the type A is selected as the power control mode, and the heat generation blocks 202-1, 202-2, 202-3, 202-4, 202-5 are selected. Is supplied with fixing maintenance power. That is, the heat generation amounts of the heat generation block 202-3 and the heat generation blocks 202-1 and 202-5 are substantially equal. Further, since the areas A-1 and A-2 and the heat generation blocks 202-1 and 202-5 are both non-sheet passing areas, the heat radiation amounts are also substantially equal. Therefore, there is a correlation between the temperatures detected by the thermistors TH1 and TH3 and the temperatures of the regions A-1 and A-2 (regions A-1, A-2: TH1, TH3 are in a ratio of, for example, 100: 95). is there. If this correlation is obtained experimentally, the temperatures of the regions A-1 and A-2 can be predicted based on the temperature stored in step 7 of the flowchart of FIG. That is, the heat generation blocks 202-1 and 202-5, which are heating regions where the non-sheet passing portion overlaps the temperature detection position by the thermistor, are set as prediction unnecessary regions, and the prediction target region is based on the detected temperature of the non-sheet passing portion. The temperature of the non-sheet passing portion of a certain heat generation block 202-3 is predicted.

  With reference to FIG. 7, the non-sheet-passing portion temperature prediction will be described by taking, as an example, a square No. 6 envelope (sheet width 162 mm) which is a sheet width for which the non-sheet-passing portion temperature prediction is performed. FIG. 7 shows the positional relationship between the heater 200 and the recording paper when the square No. 6 envelope is passed. When the square type 6 envelope is passed, at least the heat generating blocks (heat generating blocks 202-2, 202-3, 202-4) through which the square type 6 envelope passes must be maintained at a temperature at which heat fixing is performed. Therefore, the non-sheet passing portion temperature rise occurs in the areas B-1 and B-2 in FIG. Since the thermistors are not arranged in the areas B-1 and B-2, the temperature in this area cannot be directly detected.

  Here, since the width of the square type 6 envelope is 162.0 mm, from Table 1, the type A is selected as the power control mode, and the heat generation blocks 202-1, 202-2, 202-3, 202-4, 202-5 is supplied with fixing maintenance power. That is, the heat generation amounts of the heat generation blocks 202-2, 202-3, 202-4 and the heat generation blocks 202-1, 202-5 are substantially equal. Further, since the areas B-1 and B-2 and the heat generation blocks 202-1 and 202-5 are both non-sheet passing areas, the heat radiation amounts are also substantially equal. Therefore, there is a correlation between the temperatures detected by the thermistors TH1 and TH3 and the temperatures of the regions B-1 and B-2 (regions B-1, B-2: TH1, TH3 are in a ratio of, for example, 100: 95). is there. If this correlation is obtained experimentally, the temperatures of the regions B-1 and B-2 can be predicted based on the temperature stored in step 7 of the flowchart of FIG.

  The temperature rise at the non-sheet passing portion tends to increase the temperature immediately outside the recording paper (regions A-1 and A-2 in FIG. 6, regions B-1 and B-2 in FIG. 7). By predicting the temperature in this area and determining the feeding timing of the subsequent paper based on that temperature (adjusting the conveyance interval), the throughput reduction to suppress the temperature rise of the non-sheet passing portion is minimized. The amount of down can be limited.

  As described above, according to the present invention, in an image heating apparatus using a multi-split heater having a plurality of heat generating blocks in the longitudinal direction, even when the end of the sheet is located in a heat generating block without a thermistor, It can be controlled to achieve throughput.

[Example 2]
A second embodiment of the present invention will be described. In the second embodiment, the same symbols are used for the same configurations as in the first embodiment, and the description is omitted. In the first embodiment, when B6 paper is passed, fixing maintenance power is supplied to the heat generating blocks 202-1, 202-2, 202-3, 202-4, and 202-5. Here, since the heat generating blocks 202-2 and 202-4 are non-sheet passing areas and no thermistor is arranged, even if the input power to the heat generating blocks 202-2 and 202-4 is suppressed, the non-sheet passing portion There is almost no effect on the temperature prediction. Therefore, in the second embodiment, when the end of the sheet is not located in the heat generation block where the temperature of the non-sheet passing portion cannot be detected, the power consumption to the heat generation block is suppressed, thereby reducing the consumption compared to the first embodiment. Realizes the temperature prediction of the non-sheet passing part with electric power.

  The cross-sectional view of the image forming apparatus of the present embodiment, the configuration diagram of the heater 200, the heater control circuit diagram, and the control system block diagram are the same as those of the first embodiment. Since some of the contents of the processing described in the flowchart of FIG. 5 are different from the first embodiment, the description will focus on the different parts.

Step 1 performs the same processing as in the first embodiment.
In step 2, the power control mode of each heat generating block of the heater 200 is selected from the paper width information acquired in step 1. Table 2 shows the relationship between the paper width information and the power control mode, and the relationship between the paper width and whether or not the non-sheet passing portion temperature prediction is performed.

[Table 2]

Since type A, type B, and type C of the power control modes described in Table 2 are the same as those in the first embodiment, only type D will be described.
Type D is a power control mode in which fixing maintenance power is supplied to the heat generation blocks 202-1, 202-3, 202-5, and sliding maintenance power is supplied to the heat generation blocks 202-2, 202-4. is there.

  Steps 3 to 9 perform the same processing as in the first embodiment.

  With reference to FIG. 6, the non-sheet-passing portion temperature prediction in this embodiment will be described by taking as an example a B6 sheet (paper width 128 mm) that is a sheet width for which the non-sheet-passing portion temperature prediction is performed. When passing B6 paper, at least the heat generation block (heat generation block 202-3) through which the B6 paper passes must be maintained at a temperature for heat fixing. Therefore, the non-sheet passing portion temperature rise occurs in the areas A-1 and A-2 in FIG. Since the thermistors are not arranged in the areas A-1 and A-2, the temperature in this area cannot be directly detected.

  Here, since the width of B6 paper is 128.0 mm, from Table 2, the type D is selected as the power control mode, and the fixing maintenance power is input to the heat generation blocks 202-1, 202-3, and 202-5. Is done. That is, the heat generation amounts of the heat generation block 202-3 and the heat generation blocks 202-1 and 202-5 are substantially equal. Further, since the areas A-1 and A-2 and the heat generation blocks 202-1 and 202-5 are both non-sheet passing areas, the heat radiation amounts are also substantially equal. Therefore, there is a correlation between the temperatures detected by the thermistors TH1 and TH3 and the temperatures of the regions A-1 and A-2 (regions A-1, A-2: TH1, TH3 are in a ratio of, for example, 100: 95). is there. If this correlation is obtained experimentally, the temperatures of the regions A-1 and A-2 can be predicted based on the temperature stored in step 7 of the flowchart of FIG.

The temperature rise at the non-sheet passing portion tends to increase the temperature immediately outside the recording paper (areas A-1 and A-2 in FIG. 6). By predicting the temperature in this area and determining the timing for feeding the subsequent paper based on that temperature, the throughput down to suppress the temperature rise of the non-sheet-passing area is suppressed to the minimum required amount. Can do. Furthermore, in the present embodiment, only the sliding maintenance power is supplied to the heat generating blocks 202-2 and 202-4, so that the power consumption can be suppressed compared to the first embodiment.

  As described above, according to the present invention, in an image heating apparatus using a multi-split heater having a plurality of heat generating blocks in the longitudinal direction, even when the end of the sheet is located in a heat generating block without a thermistor, It can be controlled to achieve throughput.

[Example 3]
A third embodiment of the present invention will be described. In the third embodiment, the same symbols are used for the same configurations as in the first and second embodiments, and the description is omitted. In Example 2, when B6 paper is passed, fixing maintenance power is applied to the heat generation blocks 202-1, 202-3, 202-5, and sliding maintenance power is supplied to the heat generation blocks 202-2, 202-4. Was thrown in. Here, since the heat generation blocks 202-1 and 202-5 are non-sheet passing regions, it is not necessary to maintain the temperature at which the toner image is thermally fixed on the recording paper. Therefore, in the third embodiment, the temperature prediction of the non-sheet-passing portion is realized with less power consumption than the second embodiment by suppressing the power supply to the heat generating block in which the thermistor is arranged in the non-sheet-passing area. To do.

  The cross-sectional view of the image forming apparatus of the present embodiment, the configuration diagram of the heater 200, the heater control circuit diagram, and the control system block diagram are the same as those of the first embodiment. Since some of the contents of the processing described in the flowchart of FIG. 5 are different from the second embodiment, the description will focus on the different parts.

Step 1 performs the same processing as in the first embodiment.
In step 2, the power control mode of each heat generating block of the heater 200 is selected from the paper width information acquired in step 1. Table 3 shows the relationship between the paper width information and the power control mode, and the relationship between the paper width and whether or not the non-sheet passing portion temperature prediction is performed.

[Table 3]

Since type A, type B, and type C of the power control modes described in Table 3 are the same as those in the first embodiment, only type E and type F will be described.
In type E, fixing maintenance power is applied to the heat generating block 202-3, sliding maintenance power is applied to the heat generating blocks 202-2 and 202-4, and heat generating blocks are provided to the heat generating blocks 202-1 and 202-5. This is a power control mode in which two-thirds of the power input to 202-3 is input.
In type F, fixing maintenance power is applied to the heat generation blocks 202-2, 202-3, and 202-4, and the heat generation blocks 202-1 and 202-5 are supplied to the heat generation block 202-3 by 3 minutes. 2 is the power control mode.

  Steps 3 to 9 perform the same processing as in the first embodiment.

Referring to FIG. 6, B6 paper (paper width 128 m), which is the paper width on which the non-sheet passing portion temperature prediction is performed.
Taking m) as an example, the non-sheet passing portion temperature prediction in this embodiment will be described. When passing B6 paper, at least the heat generation block (heat generation block 202-3) through which the B6 paper passes must be maintained at a temperature for heat fixing. Therefore, the non-sheet passing portion temperature rise occurs in the areas A-1 and A-2 in FIG. Since the thermistors are not arranged in the areas A-1 and A-2, the temperature in this area cannot be directly detected.

  Here, since the width of the B6 sheet is 128.0 mm, from Table 3, the type E is selected as the power control mode, and the fixing maintaining power is input to the heat generation block 202-3. Further, two-thirds of the electric power supplied to the heat generation block 202-3 is input to the heat generation blocks 202-1, 202-5. That is, there is a correlation (for example, a ratio of 100: 60) between the heat generation amounts of the heat generation block 202-3 and the heat generation blocks 202-1 and 202-5. Furthermore, since the areas A-1 and A-2 and the heat generation blocks 202-1 and 202-5 are both non-sheet passing areas, the heat radiation amounts are almost equal. Therefore, there is a correlation between the temperatures detected by the thermistors TH1 and TH3 and the temperatures of the regions A-1 and A-2 (regions A-1, A-2: TH1, TH3 are in a ratio of, for example, 100: 50). is there. If this correlation is obtained experimentally, the temperatures of the regions A-1 and A-2 can be predicted based on the temperature stored in step 7 of the flowchart of FIG.

  With reference to FIG. 7, the non-sheet-passing portion temperature prediction will be described by taking, as an example, a square No. 6 envelope (sheet width 162 mm) which is a sheet width for which the non-sheet-passing portion temperature prediction is performed. When the square type 6 envelope is passed, at least the heat generating blocks (heat generating blocks 202-2, 202-3, 202-4) through which the square type 6 envelope passes must be maintained at a temperature at which heat fixing is performed. Therefore, the non-sheet passing portion temperature rise occurs in the areas B-1 and B-2 in FIG. Since the thermistors are not arranged in the areas B-1 and B-2, the temperature in this area cannot be directly detected.

  Here, since the width of the square No. 6 envelope is 162.0 mm, from Table 3, the type F is selected as the power control mode, and the fixing maintenance power is supplied to the heat generating blocks 202-2, 202-3, 202-4. It is thrown. Further, two-thirds of the electric power supplied to the heat generation block 202-3 is input to the heat generation blocks 202-1, 202-5. That is, there is a correlation (for example, a ratio of 100: 60) between the heat generation amounts of the heat generation blocks 202-2, 202-3, 202-4 and the heat generation blocks 202-1, 202-5. Further, since the areas B-1 and B-2 and the heat generation blocks 202-1 and 202-5 are both non-sheet passing areas, the heat radiation amounts are almost equal. Therefore, there is a correlation between the temperatures detected by the thermistors TH1 and TH3 and the temperatures of the regions B-1 and B-2 (regions B-1, B-2: TH1, TH3 are in a ratio of, for example, 100: 50). is there. If this correlation is obtained experimentally, the temperatures of the regions B-1 and B-2 can be predicted based on the temperature stored in step 7 of the flowchart of FIG.

  The temperature rise at the non-sheet passing portion tends to increase the temperature immediately outside the recording paper (regions A-1 and A-2 in FIG. 6, regions B-1 and B-2 in FIG. 7). By predicting the temperature in this area and determining the timing for feeding the subsequent paper based on that temperature, the throughput down to suppress the temperature rise of the non-sheet-passing area is suppressed to the minimum required amount. Can do. Furthermore, in the present embodiment, the heat generation blocks 202-1 and 202-5 are supplied with two-thirds of the power supplied to the heat generation block 202-3. Power consumption can be reduced.

  In this embodiment, two-thirds of the input power to the heat generation block 202-3 is applied to the heat generation blocks 202-1, 202-5. Any number can be used as long as the ratio can be confirmed (for example, half).

  As described above, according to the present invention, in an image heating apparatus using a multi-split heater having a plurality of heat generating blocks in the longitudinal direction, even when the end of the sheet is located in a heat generating block without a thermistor, It can be controlled to achieve throughput.

  DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 130 ... Fixing device, 132 ... Fixing film, 133 ... Pressure roller, P ... Recording paper, 200 ... Heater, 201 ... First conductor, 202-1 to 202-5 ... Heat generation block, 203 2nd conductor 204 Heater substrate TH1-TH3 Thermistor 300 Heater control circuit 320 CPU 400 Image forming device control means 401 Paper width information acquisition means 402 Power control means 403 ... Fixing temperature control means, 404 ... Non-sheet passing portion temperature prediction means, 405 ... Paper transport control means, 450 ... Controller device

Claims (10)

A heater having a plurality of heating elements arranged in a longitudinal direction perpendicular to the conveyance direction of the recording material;
A plurality of temperature detection means arranged in the longitudinal direction and detecting the temperature of a region heated by the heat of the heater;
Power control means for individually controlling the power supplied to the plurality of heating elements based on the temperature detected by the temperature detection means;
A conveyance control means for adjusting a conveyance interval when a plurality of recording materials are continuously conveyed to a region heated by the heat of the heater;
With
In an image heating apparatus for heating an image formed on a recording material by the heat of the heater,
Among the plurality of heating regions formed by the plurality of heating elements, the heating region includes a passing part through which the recording material passes and a non-passing part through which the recording material does not pass, and the non-passing part and the temperature detecting means are arranged. The temperature of the non-passing portion in the prediction target region that is a heating region that does not overlap with the temperature detection position is the detected temperature of the non-passing portion in the prediction unnecessary region that is the heating region where the non-passing portion and the temperature detection position overlap. Based on temperature prediction means for predicting,
The image heating apparatus, wherein the conveyance control unit adjusts the conveyance interval based on the temperature predicted by the temperature prediction unit. The power control means inputs the same amount of power to the prediction target region and the prediction unnecessary region,
The temperature prediction means is configured to perform the prediction based on a first predetermined ratio between the temperature of the non-sheet passing portion in the prediction target region and the detected temperature of the non-sheet passing portion in the prediction unnecessary region. The image heating apparatus according to claim 1, wherein the temperature of the non-sheet passing portion in the target area is predicted. The power control means reduces the power to be input to the prediction unnecessary area at a predetermined ratio than the power to be input to the prediction target area,
The temperature prediction unit is configured to perform the prediction based on a second predetermined ratio between the temperature of the non-sheet passing portion in the prediction target region and the detected temperature of the non-sheet passing portion in the prediction unnecessary region. The image heating apparatus according to claim 1, wherein the temperature of the non-sheet passing portion in the target area is predicted. Even if the temperature predicting means is a heating region including the passing portion and the non-passing portion, the heating region is predicted when the width in the longitudinal direction of the non-passing portion is equal to or less than a predetermined length. Not a target area,
The power control means reduces power to be input to a heating area adjacent to the heating area that has not been set as the prediction target area and not including the passing part to be less than power to be input to the heating area including the passing part. The image heating apparatus according to claim 1, wherein:   The power control means reduces power to be input to a heating area that does not include the passing portion and does not overlap the temperature detection position among the plurality of heating areas to be less than power to be input to the prediction target area. The image heating apparatus according to any one of claims 1 to 4.   The power control means individually controls the power based on a detected temperature of the passing portion in a heating region where a passing portion through which the recording material passes and the temperature detection position overlap among the plurality of heating regions. The image heating apparatus according to claim 1, wherein the image heating apparatus is one of the following.   The image heating apparatus according to claim 1, further comprising width information acquisition means for acquiring width information in the longitudinal direction of the recording material to be conveyed.   8. The apparatus according to claim 1, further comprising a cylindrical film whose inner surface rotates while being in contact with the heater, and an image on the recording material is heated through the film. 2. An image heating apparatus according to item 1. The power control means includes
A first power required to maintain a temperature at which the image is thermally fixed on the recording material;
Less than the first power, a second power required to maintain the temperature required for the film to slide relative to the heater;
The image heating apparatus according to claim 8, wherein the image heating apparatus can be charged. An image forming unit for forming an image on a recording material;
A fixing unit for fixing the image formed on the recording material to the recording material;
In an image forming apparatus having
The image forming apparatus according to claim 1, wherein the fixing unit is the image heating apparatus according to claim 1.