JP2016139003A - Image heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image heating device capable of achieving all of the suppression of temperature increase of a paper non-feeding unit, the safety, and the cost suppression.SOLUTION: The image heating device includes first wiring and second wiring. The first wiring is connected to a conductor for supplying electric power to a second heating block of the second heating block. One end of the second wiring is connected to a position other than the position connected to the first wiring on the conductor connected to the first wiring of the second heating block. The other end of the second wiring is connected to a conductor for supplying electric power to a first heating block of the first heating block. Electric power is supplied to the first heating block via the second wiring and the conductor connected to the first wiring of the second heating block.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fixing device mounted on an electrophotographic recording type image forming apparatus such as a copying machine or a printer, or a gloss applying device for improving the glossiness of a toner image by reheating a fixed toner image on a recording material. The present invention relates to an image heating apparatus.

  As an image heating apparatus, there is an apparatus having an endless belt (also referred to as an endless film), a heater that contacts an inner surface of the endless belt, and a roller that forms a nip portion with the heater via the endless belt. When small-size paper is continuously printed by an image forming apparatus equipped with this image heating device, a phenomenon (temperature increase of the non-sheet passing portion) occurs in which the temperature of the region where the paper does not pass in the longitudinal direction of the nip portion gradually increases. If the temperature of the non-sheet passing part becomes too high, the parts in the device will be damaged, or if printing on large size paper with the non-sheet passing part temperature rise, the non-sheet passing part of small size paper The toner may be offset to the endless belt at a high temperature in a region corresponding to.

  As one method for suppressing the temperature rise of the non-sheet passing portion, the heating element on the heater substrate is formed of a material having a positive resistance temperature characteristic. Then, two conductors are arranged at both ends of the substrate in the short direction so that a current flows in the short direction of the heater (recording paper conveyance direction) with respect to the heating element (hereinafter referred to as conveyance direction power feeding). It is thought to do (patent document 1). The idea that when the temperature of the non-sheet-passing part rises, the resistance value of the heating element of the non-sheet-passing part increases, and the current flowing through the heating element of the non-sheet-passing part is suppressed, thereby suppressing the heat generation of the non-sheet passing part. It is. The positive resistance temperature characteristic is a characteristic in which the resistance value increases as the temperature increases, and is hereinafter referred to as PTC (Positive Temperature Coefficient).

JP 2011-151003 A

  However, even with such a heater, a current also flows through the heating element located in the non-sheet passing portion. In addition, a device that increases the safety of the device and a device that suppresses the cost are also required.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image heating apparatus that can achieve both suppression of temperature rise in a non-sheet passing portion, safety, and cost reduction.

  The present invention for solving the above-described problems includes an endless belt, a substrate, a first heat generation block provided on the substrate, and the first heat generation block of the substrate in the longitudinal direction of the substrate. A second heat generation block provided at a position different from the position where the second heat generation block is provided, and a heater in contact with the inner surface of the endless belt. The first wiring connected to a conductor for supplying power to the heat generation block, and the first conductor connected to the conductor to which the first wiring of the second heat generation block is connected. A second wiring connected at a position different from a position where the wiring is connected and having the other end connected to a conductor for supplying power to the first heat generating block of the first heat generating block; Have, before And the conductor in which the first wiring of the second heating blocks are connected, the second wiring, the power to the first heating block via is characterized in that it is supplied.

  ADVANTAGE OF THE INVENTION According to this invention, the image heating apparatus which can make suppression of the temperature rise of a non-sheet passing part, safety | security, and cost reduction compatible can be provided.

1 is a cross-sectional view of an image forming apparatus. Sectional drawing of an image heating apparatus. FIG. 2 is a heater configuration diagram according to the first embodiment. FIG. 3 is a control circuit diagram of the first embodiment. Explanatory drawing regarding the heater contact part and wiring of Example 1. FIG. The wiring diagram of the comparative example 1. FIG. Explanatory drawing regarding the heater structure of Example 2, a contact part, and wiring.

Example 1
FIG. 1 is a sectional view of a laser printer (image forming apparatus) 100 using an electrophotographic recording technique. When the print signal is generated, the scanner unit 21 emits a laser beam modulated according to the image information, and scans the photoconductor 19 charged to a predetermined polarity by the charging roller 16. As a result, an electrostatic latent image is formed on the photoreceptor 19. Toner is supplied from the developing unit 17 to the electrostatic latent image, and a toner image corresponding to image information is formed on the photoreceptor 19. On the other hand, the recording material (recording paper) P loaded in the paper feeding cassette 11 is fed one by one by the pickup roller 12 and conveyed toward the registration roller 14 by the roller 13. Further, the recording material P is conveyed from the registration roller 14 to the transfer position in accordance with the timing at which the toner image on the photoconductor 19 reaches the transfer position formed by the photoconductor 19 and the transfer roller 20. The toner image on the photoconductor 19 is transferred to the recording material P while the recording material P passes through the transfer position. Thereafter, the recording material P is heated by a fixing device 200 as an image heating device, and the toner image is heated and fixed on the recording material P. The recording material P carrying the fixed toner image is discharged to a tray above the laser printer 100 by rollers 26 and 27. Reference numeral 18 denotes a cleaner for cleaning the photosensitive member 19, and reference numeral 28 denotes a paper feed tray (manual feed tray) having a pair of recording material regulating plates whose width can be adjusted according to the size of the recording material P. The paper feed tray 28 is provided to accommodate recording materials P having a size other than the standard size. A pickup roller 29 feeds the recording material P from the paper feed tray 28, and a motor 30 drives the fixing device 200 and the like. Power is supplied to the fixing device 200 from a control circuit 2400 connected to a commercial AC power supply 401. The photosensitive member 19, the charging roller 16, the scanner unit 21, the developing device 17, and the transfer roller 20 described above constitute an image forming unit that forms an unfixed image on the recording material P.

  The laser printer 100 of this embodiment supports a plurality of recording material sizes. Letter paper (about 216 mm × 279 mm), Legal paper (about 216 mm × 356 mm), A4 paper (210 mm × 297 mm), and executive paper (about 184 mm × 267 mm) can be set in the paper feed cassette 11. Furthermore, JIS B5 paper (182 mm × 257 mm) and A5 paper (148 mm × 210 mm) can be set.

  Further, from the paper feed tray 28, it is possible to feed and print indefinite form paper including a DL envelope (110 mm × 220 mm) and a COM10 envelope (about 105 mm × 241 mm). The printer of this example is a laser printer that basically feeds paper vertically (conveys so that the long side is parallel to the conveyance direction). The recording materials having the largest (largest width) width among the standard recording material widths (the widths of the recording materials on the catalog) supported by the apparatus are Letter paper and Legal paper. Is about 216 mm. In this embodiment, the recording material P having a paper width smaller than the maximum size supported by the apparatus is defined as a small size paper.

  FIG. 2 is a cross-sectional view of the fixing device 200. The fixing device 200 includes a cylindrical film (endless belt) 202, a heater 700 that contacts the inner surface of the film 202, and a pressure roller (nip portion forming member) that forms a fixing nip portion N together with the heater 700 via the film 202. 208). The material of the base layer of the film 202 is a heat resistant resin such as polyimide or a metal such as stainless steel. Further, an elastic layer such as heat resistant rubber may be provided on the surface layer of the film 202. The pressure roller 208 includes a cored bar 209 made of iron or aluminum and an elastic layer 210 made of silicone rubber or the like. The heater 700 is held by a holding member 201 made of heat resistant resin. The holding member 201 also has a guide function for guiding the rotation of the film 202. The pressure roller 208 receives power from the motor 30 and rotates in the direction of the arrow. As the pressure roller 208 rotates, the film 202 is driven and rotated. The recording material P carrying the unfixed toner image is heated and fixed while being nipped and conveyed by the fixing nip portion N.

  FIG. 3 is a configuration diagram of the heater 700. As shown in FIG. 3A, the heater 700 has a heating element on a ceramic substrate 305. Thermistors TH <b> 1 to TH <b> 4 as temperature detection elements are in contact with the back side of the substrate 305 and the paper passing area of the laser printer 100. A safety element 212 such as a thermo switch or a thermal fuse that is operated by the abnormal heat generation of the heater 700 and cuts off the power supplied to the heater 700 is also in contact with the back surface side of the substrate 305. Reference numeral 204 denotes a metal stay for applying a spring pressure (not shown) to the holding member 201.

  FIG. 3A shows a cross-sectional view of the heater 700 in the short direction. The heater 700 includes a first conductor 701 provided on the substrate 305 along the longitudinal direction of the heater 700, and the heater 700 at different positions on the substrate 305 in the short direction of the first conductor 701 and the heater 700. It has the 2nd conductor 703 provided along the longitudinal direction. The first conductor 701 is separated into a conductor 701a disposed on the upstream side in the conveyance direction of the recording material P and a conductor 701b disposed on the downstream side.

  Further, the heater 700 is provided between the first conductor 701 and the second conductor 703 and generates heat by the power supplied via the first conductor 701 and the second conductor 703. 702. The heating element 702 is separated into a heating element 702a arranged on the upstream side in the conveyance direction of the recording material P and a heating element 702b arranged on the downstream side. Each heating element has a positive resistance temperature characteristic.

  When the heat generation distribution in the short direction of the heater 700 (the conveyance direction of the recording material) is asymmetric, the stress generated on the substrate 305 when the heater 700 generates heat increases. When the stress generated in the substrate 305 increases, the substrate 305 may be cracked. Therefore, the heating element 702 is separated into a heating element 702a disposed on the upstream side in the conveying direction and a heating element 702b disposed on the downstream side so that the heat generation distribution in the short direction of the heater 700 is symmetric. .

  The layer 2 on the back surface of the heater 700 is provided with an insulating (glass in this embodiment) surface protective layer 707 that covers the heating element 702, the first conductor 701, and the second conductor 703. In addition, the layer 1 on the sliding surface of the heater 700 (the surface in contact with the endless belt) has a surface protective layer 308 made of a slidable glass or polyimide coating.

  FIG. 3B shows a plan view of each layer of the heater 700. The heater 700 back surface layer 1 is provided with a plurality of heat generation blocks in the longitudinal direction of the heater 700, each of which includes a set of a first conductor 701, a second conductor 703, and a heat generator 702. The heater 700 of this embodiment has a total of seven heat generating blocks BL1 to BL7.

  Each of the heat generating blocks BL1 to BL7 includes a heat generating element 702a (702a-1 to 702a-7) and a heat generating element 702b (702b-1 to 702b-7) formed symmetrically in the short direction of the heater 700. The first conductor 701 includes a conductor 701a connected to the heating element 702a (702a-1 to 702a-7) and a conductor 701b connected to the heating element 702b (702b-1 to 702b-7). . The second conductor 703 is divided into seven (703-1 to 703-7).

  The division position of the heat generation block in the heater longitudinal direction is adjusted to the size of the recording material P. Note that power control to the heater 700 is performed based on the output of the thermistor TH1 provided near the center of the sheet passing portion (near the conveyance reference position X). The printer of this example is configured to convey the recording material in the center in the width direction in accordance with the reference position X.

  Use BL4 when printing on DL and COM10 envelopes. When printing on A5 paper, use BL3 to BL5. Similarly, for Executive paper and B5 paper, BL2 to BL6 are used. For Letter paper, Legal paper, and A4 paper, BL1 to BL7, that is, all heat generation blocks are used. The number of divisions and the division position are not limited to the configuration of the present embodiment. As described above, since the block that generates heat is selected in accordance with the size of the recording material, it is possible to suppress the heat generation in the region where the recording material of the heater does not pass. Further, as described above, each heating element of this example has a positive resistance temperature characteristic. For this reason, even if the end in the width direction of the recording material passes through the area of one heat generation block instead of the division position between adjacent heat generation blocks, the heat generation of the portion of the heat generation block that protrudes from the end of the recording material Can also be suppressed. The heating element does not necessarily have a positive resistance temperature characteristic, and the resistance temperature characteristic may be zero or more.

  A power supply wiring, which will be described later, is connected to the electrodes E1 to E7, E8-1, and E8-2. The electrodes E1 to E7 are electrodes for each heat generation block. Electrodes E8-1 and E8-2 are electrodes common to all the heat generating blocks.

  Further, the surface protective layer 707 of the layer 2 on the back surface of the heater 700 is formed except for the positions of the electrodes E1 to E7, E8-1, and E8-2, and is used to supply power to each electrode from the back surface side of the heater 700. The electrical contacts of the wiring can be connected.

  The heat generation blocks BL1 and BL7 are arranged at symmetrical positions with respect to the recording material conveyance reference X in the longitudinal direction of the heater (longitudinal direction of the substrate). In this example, two heat generation blocks having a symmetrical positional relationship with respect to the conveyance reference X are referred to as a first heat generation block and a second heat generation block. That is, the heat generation block BL1 is a first heat generation block, and the heat generation block BL7 is a second heat generation block. The heat generation block BL2 is a first heat generation block, and the heat generation block BL6 is a second heat generation block. Further, the heat generation block BL3 is a first heat generation block, and the heat generation block BL5 is a second heat generation block. Thus, the heater has a plurality of sets each including the first heat generation block and the second heat generation block. Note that there is no heat generating block paired with the heat generating block BL4 provided at the position of the conveyance reference X. However, in order to simplify the description, the following description deals with the heat generation block BL4 as one set.

  FIG. 4 shows a control circuit 2400 of the heater 700. Reference numeral 401 denotes a commercial AC power source connected to the laser printer 100. The control circuit 2400 includes four triacs (drive elements) 416, 426, 436, and 446. Each triac is an element for controlling the power supplied to one set of heat generating blocks. By the energization / interruption of each triac, a set of heat generating blocks connected to each triac is controlled independently for each group. Note that switching of the heat generation distribution in the heater longitudinal direction may be achieved by a configuration other than the configuration in which a dedicated triac as shown in FIG. 4 is provided. For example, a configuration may be employed in which a set to be used is selected using one or more relays, and all the selected sets are controlled using one drive element (triac).

  The triac 416 is connected to the electrode E4 and used for controlling the heat generating block BL4. The triac 426 is connected to the electrode E5 and is used for controlling the set of the heat generating blocks BL3 and BL5. Similarly, the triac 436 is connected to the electrode E6 and is used for controlling the set of the heat generating blocks BL2 and BL6. The triac 446 is connected to the electrode E7 and is used for controlling the set of the heat generating blocks BL1 and BL7.

  The zero cross detection unit 430 is a circuit that detects a zero cross of the AC power supply 401, and outputs a ZEROX signal to the CPU 420. The ZEROX signal is used for controlling the heater 700.

  The relay 450 is used as a means for interrupting power to the heater 700 that operates according to outputs from the thermistors TH1 to TH4 (cuts off power supply to the heater 700) when the heater 700 is overheated due to failure or the like.

  When the RLON 440 signal is in the high state, the transistor 453 is in the on state, and the secondary coil of the relay 450 is energized from the power supply voltage Vcc2, and the primary contact of the relay 450 is in the on state. When the RLON 440 signal becomes low, the transistor 453 is turned off, the current flowing from the power supply voltage Vcc2 to the secondary coil of the relay 450 is cut off, and the primary contact of the relay 450 is turned off. The resistor 454 is a current limiting resistor.

  Next, the operation of the safety circuit 455 using the relay 450 will be described. When any one of the detected temperatures by the thermistors TH1 to TH4 exceeds a set predetermined value, the comparison unit 451 operates the latch unit 452, and the latch unit 452 latches the RLOFF signal in the low state. When the RLOFF signal is in a low state, even if the CPU 420 sets the RLON440 signal to a high state, the transistor 453 is kept in the off state, so that the relay 450 can be kept in the off state (safe state).

  When the detected temperatures by the thermistors TH1 to TH4 do not exceed the set predetermined values, the RLOFF signal of the latch unit 452 is in an open state. For this reason, when the CPU 420 sets the RLON 440 signal to the high state, the relay 450 can be turned on and power can be supplied to the heater 700.

  Next, the operation of the triac 416 will be described. Resistors 413 and 417 are bias resistors for the triac 416, and the phototriac coupler 415 is a device for securing a creepage distance between the primary and secondary. Then, the triac 416 is turned on by energizing the light emitting diode of the phototriac coupler 415. The resistor 418 is a resistor for limiting the current flowing from the power supply voltage Vcc to the light emitting diode of the phototriac coupler 415, and turns on / off the phototriac coupler 415 by the transistor 419. The transistor 419 operates in accordance with the FUSER1 signal from the CPU 420.

  When the triac 416 is energized, power is supplied to the heating elements 702a-4 and 702b-4.

  Since the circuit operation of the triacs 426, 436, and 446 is the same as that of the triac 416, the description is omitted. The triac 426 operates in accordance with the FUSER2 signal from the CPU 420, and controls the power supplied to the heating elements 702a-5, 702b-5, 702a-3, and 702b-3. The triac 436 operates in accordance with the FUSER3 signal from the CPU 420, and controls power supplied to the heating elements 702a-6, 702b-6, 702a-2, and 702b-2. The triac 446 operates in accordance with the FUSER4 signal from the CPU 420, and controls power supplied to the heating elements 702a-7, 702b-7, 702a-1, and 702b-1.

  Next, a heater temperature control method will be described. The temperature detected by the thermistor TH1 provided in the region of the heat generation block BL4 including the transport reference X is input to the CPU (control unit) 420 as a TH1 signal. Also, the recording material size information is input to the CPU, and a set of heat generating blocks to generate heat is selected. Further, the CPU 420 calculates the power to be supplied (control level) by, for example, PI control (Proportional-Integral Control) based on the detected temperature of the thermistor TH1 and the control target temperature of the heater. The CPU transmits a FUSER signal (FUSER1 to FUSER4) to the triac corresponding to the selected set so that the current flowing through the heater has a phase angle and a wave number corresponding to the calculated control level.

  In this embodiment, the temperature control of the heater 700 is performed based on the heater temperature detected by the thermistor TH1. However, the thermistor TH1 may be configured to detect the temperature of the film 202, and the temperature control of the heater 700 may be performed based on the temperature of the film 202.

  Next, a connection configuration of power supply wiring will be described. FIG. 5A is a plan view of the holding member 201. As described in FIG. 2, the back layer 2 of the heater 700 is in contact with the holding member 201. The holding member 201 is provided with holes at positions overlapping the electrodes E1 to E7, E8-1, and E8-2 of the heater 700 and positions where the thermistors TH1 to TH4 abut.

  Wirings 501a, 501b, 502a to 505a, and 503b to 505b connected to the control circuit 2400 pass through holes provided in the holding member and are connected to each electrode of the heater. Note that the electrode is a portion where wiring is connected to the conductor, and can be regarded as a part of the conductor.

  The apparatus of this example includes a first wiring connected to a conductor for supplying power to the second heat generation block of the second heat generation block. Further, one end is connected to the conductor to which the first wiring of the second heat generation block is connected at a position different from the position where the first wiring is connected, and the other end is connected to the first heat generation. A second wiring connected to a conductor for supplying power to the first heat generating block of the block; And it is the structure by which electric power is supplied to a 1st heat_generation | fever block via the conductor and the 2nd wiring to which the 1st wiring of the 2nd heat_generation | fever block was connected. This will be specifically described below.

  The wiring 501a is connected to the electrode E8-2, and the wiring 501b is connected to the electrode E8-1. A wiring 502a connected to the triac 416 is connected to the electrode E4.

  A wiring 503a (first wiring) connected to the triac 426 is connected to an electrode E5 that is an electrode of the second heat generation block BL5 in the pair of BL3 (first heat generation block) and BL5 (second heat generation block). Has been. That is, the wiring 503a (first wiring) is equivalent to being connected to the conductor 703-5 of the second heat generation block BL5. The wiring 503b (second wiring) has one end connected to the electrode E5 of the second heat generation block BL5 and the first wiring 503a, and the other end connected to the electrode E3 of the first heat generation block BL3. It is connected to the. That is, the second wiring 503b has one end connected to the conductor 703-5 to which the first wiring 503a is connected, and the other end connected to the first heat generation block BL3. It is equivalent to being connected to the conductor 703-3. Note that the connection position of the second wiring 503b to the electrode E5 is different from the connection position of the first wiring 503a to the electrode E5. Thus, the second wiring 503b is connected to the electrode E3 with the electrode E5 as a relay point. And the temperature detection element TH2 is arrange | positioned in the position which detects the temperature of 2nd heat_generation | fever block BL5, and the temperature detection element is not provided in the position corresponding to 1st heat_generation | fever block BL3.

  The wiring configuration of BL2 and BL6 controlled using the triac 436 and the configuration of BL1 and BL7 controlled using the triac 446 are similar to the wiring configuration of the BL3 and BL5 set controlled using the triac 426. It has become. That is, the second wiring 504b is connected to the electrode E2 using the electrode E6 as a relay point. The second wiring 505b is connected to the electrode E1 with the electrode E7 as a relay point. The temperature detection element TH3 is disposed at a position where the temperature of the second heat generation block BL6 is detected, that is, at the position of the heat generation block where the relay point E6 is located. The temperature detection element TH4 is disposed at a position where the temperature of the second heat generation block BL7 is detected, that is, at a position of the heat generation block where the relay point E7 is located.

  As described above, in the set of two heat generation blocks, power is supplied to the first heat generation block via the conductor connected to the first wiring of the second heat generation block and the second wiring. It becomes the composition which is done. In addition, the temperature detection element that monitors the temperature of the heat generation block is provided only in the second heat generation block having the electrode serving as a relay point among the first heat generation block and the second heat generation block.

  FIG. 5B shows a cross-sectional view at the Y position in FIG. The wirings 503a and 503b are connected to the surface of the electrode E5 by independent contact points a and b. That is, power is supplied to the heat generation block BL3 that is the second heat generation block via the electrode E5 (conductor 703-5) of the heat generation block BL5 that is the first heat generation block. Similarly, the wirings 504a and 504b are connected to the electrode E6, and the wirings 505a and 505b are connected to the electrodes at the electrode E7 by independent contacts.

  Next, the merit that two wirings are independently connected to one conductor of the second heat generation block will be described. For example, the wiring 503b is branched in the middle of the wiring 503a and connected to the heat generation block BL3 (referred to as Comparative Example 1), or the wiring 503a and the wiring 503b are connected to the electrode E5 at the same position (contact point) on the electrode E5. Consider a connected configuration (Comparative Example 2). FIG. 6 shows a circuit diagram of the first comparative example. In FIG. 6, the heat generating blocks other than the heat generating blocks BL3, BL4, and BL5 are omitted.

  In the case of the comparative example 1, even if the wiring 503a is disconnected from the electrode E5, the wiring 503b to the electrode E3 remains connected. Therefore, in consideration of a case where the heat generation block BL3 abnormally generates heat due to an abnormality of the CPU or the like, it is necessary to arrange a temperature detection element at the position of the heat generation block BL3 and detect abnormal heat generation. That is, temperature detection elements are required not only at the position of the heat generation block BL5 but also at the position of the heat generation block BL3.

  In the case of the comparative example 2, when the wiring 503a is disconnected from the electrode E5, the wiring 503b may be disconnected from the electrode E5 while being electrically connected to the wiring 503a. In this case, the heat generation block BL5 does not generate heat, but the heat generation block BL3 generates heat. Therefore, as in Comparative Example 1, in consideration of the case where the heat generation block BL3 abnormally generates heat due to an abnormality in the CPU or the like, it is necessary to arrange a temperature detection element at the position of the heat generation block BL3 and detect abnormal heat generation. . That is, temperature detection elements are required not only at the position of the heat generation block BL5 but also at the position of the heat generation block BL3.

  On the other hand, in the connection configuration of this embodiment, even if the contact a (wiring 503a) is accidentally disconnected, the contact b is not disconnected while the wiring 503a and the wiring 503b are electrically connected. In this case, since the wiring 503a is disconnected from the electrode E5, abnormal heat generation does not occur in the heat generation block BL5, and abnormal heat generation does not occur in the heat generation block BL3. When the wiring 503b (setting b) is disconnected from the electrode E5, the heat generation block BL3 does not generate heat, and only the heat generation block BL5 may abnormally generate heat. However, since the temperature detection element TH2 is provided at the position of the heat generation block BL5, abnormal heat generation can be detected by this temperature detection element TH2. In other words, with the wiring configuration as in this example, in the set of the heat generation block BL3 and the heat generation block BL5, there is no state in which only the heat generation block BL3 generates heat, so it is not necessary to provide a temperature detection element at the position of the heat generation block BL3. . As described above, in the set of two heat generation blocks, the conductor (703-5) to which the first wiring (503a) of the second heat generation block (BL5) is connected, the second wiring (503b), and , Power is supplied to the first heat generating block (BL3). With this configuration, the cost of the apparatus can be reduced.

(Example 2)
FIG. 7 is a diagram showing a wiring configuration for the heater and power supply of this example. This example is different from Example 1 in that an electrode for each wiring is provided for one conductor to which both the first wiring and the second wiring are connected. Other configurations are the same as those of the first embodiment.

  As shown in FIG. 7A, the heater 770 of this example includes E5-1 and E5-2 as electrodes corresponding to the conductor 703-5. Similarly, E6-1 and E6-2 are provided as electrodes corresponding to the conductor 703-6, and E7-1 and E7-2 are provided as electrodes corresponding to the conductor 703-7. Since the heater 770 has more electrodes than the heater 700 of the first embodiment, as shown in FIG. 7B, the number of holes corresponding to each electrode of the holding member 2201 that holds the heater 770 is also increased.

  As shown in FIG. 7B, the wiring 503a is connected to the electrode E5-1, and the wiring 503b is connected to the electrode E5-2 and the electrode E3. Similarly, the wiring 504a is connected to the electrode E6-1, and the wiring 504b is connected to the electrode E6-2 and the electrode E2. The wiring 505a is connected to the electrode E7-1, and the wiring 505b is connected to the electrode E7-2 and the electrode E1.

  7C is a cross-sectional view at the Y position in FIG. 7B, and FIG. 7D is a cross-sectional view at the Y ′ position in FIG. 7B. The wiring 503a is in contact with the electrode E5-1 at the contact c, and the wiring 503b is in contact with the electrode E5-2 at the contact d. As described above, the electrode E5-1 and the electrode E5-2 are both electrodes of the conductor 703-5. Since the wiring and contact configurations of the other heat generating block groups are the same, the description thereof is omitted.

  Also in the configuration of this example, as in Example 1, the conductor (703-5) to which the first wiring (503a) of the second heat generation block (BL5) is connected, the second wiring (503b), The power is supplied to the first heat generating block (BL3) via the. In addition, an electrode E5-1 of the conductor 703-5 to which the first wiring 503a is connected and an electrode E5-2 of the conductor 703-5 to which the second wiring 503b is connected are individually provided. Therefore, as in the first embodiment, the wiring 503a and the wiring 503b are not disconnected while being electrically connected, and only the heat generation block BL3 does not generate heat in the heat generation block BL3 and the heat generation block BL5. Therefore, it is not necessary to provide a temperature detection element at the position of the heat generation block BL3.

  Further, since the wiring can be shortened by the distance L between the electrode E5-1 (position Y) and the electrode E5-2 (position Y ′), the cost can be suppressed.

  In Examples 1 and 2, each wiring uses a cable with an insulation coating, and welding is adopted as the connection method to the electrodes. However, other cables and connection methods may be adopted.

701 First conductor 702 Heating element 703 Second conductor E1 to E7 Second conductor electrode TH1 to TH4 Temperature sensing element 503a to 505a First wiring 503b to 505b Second wiring

Claims (6)

Endless belt,
A substrate, a first heat generation block provided on the substrate, and a second heat generation block provided at a position different from the position where the first heat generation block is provided on the substrate in the longitudinal direction of the substrate; And a heater in contact with the inner surface of the endless belt,
In an image heating apparatus having
A first wiring connected to a conductor for supplying power to the second heat generation block of the second heat generation block is connected to the first wiring of the second heat generation block at one end. In addition, the other end is connected to the conductor at a position different from the position where the first wiring is connected, and the other end is a conductor for supplying power to the first heat generating block of the first heat generating block. A second wiring connected to the body, and the first conductor of the second heat generation block is connected to the first wiring, and the second wiring is connected to the first wiring. An image heating apparatus, wherein power is supplied to one heating block.   The apparatus further includes a temperature detection element for detecting the temperature of the heater, the temperature detection element is provided at a position corresponding to the second heat generation block, and corresponds to the first heat generation block. The image heating apparatus according to claim 1, wherein the temperature detecting element is not provided at a position.   The first heat generating block and the second heat generating block are respectively a first conductor provided on the substrate along a longitudinal direction of the substrate, and the first conductor on the substrate is the substrate. A second conductor provided along the longitudinal direction at a different position in the lateral direction, and provided between the first conductor and the second conductor, the first conductor and the first conductor The image heating apparatus according to claim 1, further comprising a heating element that generates heat by electric power supplied via the two conductors.   The first heat generation block and the second heat generation block are arranged at positions symmetrical with respect to a recording material conveyance reference in the longitudinal direction. The image heating apparatus described in 1.   5. The image heating apparatus according to claim 1, wherein the heater includes a plurality of sets each including the first heat generation block and the second heat generation block.   The image heating apparatus according to claim 3, wherein the heating element has a positive resistance temperature characteristic.

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