JP2009063814A - Image heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image heating device, capable of feeding electricity to a heater which generates heat from the whole body of a substrate by energization by use of a surface of the substrate. <P>SOLUTION: The image heating device 22 includes the heater 1 which generates heat by energization; feeding members 3a and 3b which energizes to the heater; and a heating member 33 to be heated by the heater, which heats an image t supported by a recording material P. The heater has a slender substrate 2 which is entirely heated by energization, and the feeding members are in face contact with the substrate at both longitudinal ends of the substrate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image heating apparatus suitable for use as an image heating fixing apparatus (fixing device) mounted on an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer.

  As an image heating device (fixing device) mounted on an image forming apparatus such as an electrophotographic copying machine or a printer, there is a film heating type. A film heating type fixing device includes a heater having a heating element on a ceramic substrate, a flexible member that moves while contacting the heater, and a heater and a nip portion that are formed via the flexible member. And a pressure roller. The recording material carrying the unfixed toner image is heated while being nipped and conveyed by the nip portion of the fixing device, whereby the toner image on the recording material is heated and fixed on the recording material. This fixing device has an advantage that it takes a short time to start energizing the heater and raise the temperature to a fixable temperature. Therefore, the printer equipped with this fixing device can shorten the time (FPOT: First Print Out Time) until the first image is output after the print command is input. In addition, this fixing device has an advantage that power consumption during standby waiting for a print command is small.

  By the way, when a small-sized recording material is continuously printed at the same print interval as a large-sized recording material with a printer equipped with a fixing device using a flexible member, the area where the recording material of the heater does not pass (non-sheet passing area) Is known to overheat. If the non-sheet passing area of the heater is excessively heated, the holder and the pressure roller that hold the heater may be damaged by heat. Therefore, a printer equipped with a fixing device that forms a fixing nip portion with a heater and a pressure roller through a flexible member, when continuously printing on a small size recording material, when printing continuously on a large size recording material Control is performed to widen the print interval. Thereby, the excessive temperature rise in the non-sheet passing area of the heater is suppressed.

  Therefore, it is also considered to use a heater (NTC: Negative Temperature Coefficient) whose resistance value decreases as the temperature rises as a heater used in the above-described fixing device. If the heater has NTC characteristics, the resistance value of the non-sheet passing area is lowered even if the non-sheet passing area is excessively heated, so that excessive temperature rise in the non-sheet passing area, that is, so-called non-sheet passing portion temperature increase can be suppressed. This is the idea.

  In a heater having a heating element on a ceramic substrate, a heater can be obtained by screen-printing a paste-like electric resistor having NTC characteristics on the ceramic substrate as a heating element and performing a firing process (patent) Reference 1).

On the other hand, a heating element having NTC characteristics generally has high resistance, and cannot take advantage of the above-described fixing device, which requires a short time to start energizing the heater and raise the temperature to a fixable temperature. . Therefore, there is a case where a material having NTC characteristics is used after being processed into an elongated substrate. Patent Document 2 describes a carbon heater. In this way, by using a material having NTC characteristics in a bulk state, the total resistance as a heater can be reduced, the rise to the fixing possible temperature and the rise of the non-sheet passing portion during small size continuous printing. It becomes possible to achieve both temperature suppression.
JP 06-019347 A JP 2006-154802 A

  When a fuser is provided with a bulk heater in which a long and narrow substrate is integrally formed of a material having NTC characteristics, both ends in the longitudinal direction of the bulk heater substrate are sandwiched by connectors, and the substrate is energized. The whole generates heat. For this reason, in a fixing device equipped with a bulk heater, both ends in the longitudinal direction of the substrate sandwiched between the connectors also become heat generating regions and the connector heats up. Therefore, power can be supplied to the bulk heater substrate without using the connector. desired.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image heating apparatus that can supply power to a heater that generates heat when energized by utilizing the surface of the substrate.

  A configuration for achieving the above object includes a heater that generates heat by energization, a power supply member that energizes the heater, and a heating member that is heated by the heater, and that heats an image carried by a recording material. In the image heating apparatus, the heater is a slender substrate, and the substrate has a substrate that generates heat when energized, and the power supply member has a surface of the substrate at both longitudinal ends of the substrate. It is characterized by being in contact.

  In addition, a configuration for achieving the above object includes a heater that generates heat by energization, a power supply member that energizes the heater, a heating member that moves while being in contact with the heater, and the heater that sandwiches the heating member. A pressure member that forms a nip portion, and an image heating apparatus that heats an image while sandwiching and conveying a recording material that carries an image at the nip portion, wherein the heater is orthogonal to the conveyance direction of the recording material The substrate has a substrate that is elongated in the direction and generates heat when energized. The power supply member is in contact with the surface of the substrate portion at both ends in the longitudinal direction of the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the image heating apparatus which enabled electric power supply using the surface of a board | substrate with respect to the heater which the whole board | substrate heat | fever-generates by electricity supply can be provided.

  The present invention will be described with reference to the drawings.

[Example 1]
Hereinafter, the present invention will be described in detail with reference to the drawings.

(1) Example of Image Forming Apparatus FIG. 1 is a structural model diagram of an example of an image forming apparatus in which the image heating apparatus according to the present invention can be mounted as an image heating fixing apparatus (fixing device). This image forming apparatus is an electrophotographic laser beam printer.

  Reference numeral 11 denotes a drum-type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) as an image carrier. For example, an organic photosensitive drum in which a photosensitive layer such as an organic photoconductor is formed on the outer peripheral surface of a conductive drum base such as aluminum.

  Reference numeral 12 denotes a charging roller as charging means. The charging roller 12 uniformly charges the outer peripheral surface (surface) of the photosensitive drum to a predetermined polarity and potential.

  Reference numeral 10 denotes a laser exposure apparatus. The laser exposure apparatus 10 outputs a laser beam L modulated in accordance with image information input from an external device such as an image scanner or a computer (not shown). This laser beam scans and exposes the uniformly charged surface on the surface of the photosensitive drum 11. This scanning exposure attenuates or eliminates the charge in the exposed bright portion of the photosensitive drum surface, and an electrostatic latent image corresponding to the image information is formed on the photosensitive drum surface.

  Reference numeral 13 denotes a developing device as developing means. The developing device 13 includes a developing roller 13a. The roller 13a visualizes the electrostatic latent image on the surface of the photosensitive drum 11 as a toner image (developed image) with toner (developer).

  Reference numeral 17 denotes a paper feed cassette in which recording materials (transfer materials) P are stacked and stored. Based on the paper feed start signal, the paper feed roller 18 is rotated and the recording materials P in the paper feed cassette 17 are separated and fed one by one. The fed recording material P is conveyed to a registration roller pair 21 through a sheet path 20 by a conveyance roller 19. Then, the registration roller pair 21 is introduced into the transfer portion T, which is a contact nip portion between the photosensitive drum 11 and the transfer roller 16, at a predetermined control timing.

  The recording material P introduced into the transfer portion T is nipped and conveyed by the transfer portion T, and during that time, the toner image on the surface of the photosensitive drum 11 is electrostatically transferred sequentially onto the recording material P surface by the transfer roller 16.

  The recording material P that has received the transfer of the toner image at the transfer portion T is separated from the surface of the photosensitive drum 11 and then conveyed to the fixing device 22 where it undergoes a heat fixing process for the toner image.

  On the other hand, the surface of the photosensitive drum 11 after separation of the recording material (after transfer of the toner image to the recording material) is cleaned by the cleaning blade 14a of the cleaning device 14 to remove the adhering matter such as residual toner and paper dust, and repeatedly To be used for image formation.

  The recording material P that has passed through the fixing device 22 is sent to the paper discharge roller 24 by the transport roller 23. The paper is discharged onto a paper discharge tray 25 on the upper surface of the printer by the paper discharge roller 24.

  The printer according to the present embodiment includes a process cartridge 15 that can be attached to and detached from the printer body in a batch with respect to four process devices including a photosensitive drum 11, a charging roller 12, a developing device 13, and a cleaning device 14. It is configured as.

(2) Fixing device (image heating device) 22
In the following description, regarding the fixing device and the members constituting the fixing device, the longitudinal direction is a direction orthogonal to the recording material conveyance direction on the surface of the recording material. The short side direction is a direction parallel to the recording material conveyance direction on the surface of the recording material. The length is a dimension in the longitudinal direction. The width is a dimension in the short direction.

  FIG. 2 is a cross-sectional configuration model diagram of an example of the fixing device 22. FIG. 3 is a longitudinal sectional configuration model diagram of the fixing device 22. FIG. 4 is a view of the fixing device 22 as viewed from the recording material introduction side. The fixing device 22 is a tensionless type film heating type image heating device disclosed in Japanese Patent Application Laid-Open Nos. 4-44075 to 44083, Japanese Patent Application Laid-Open No. 4-20420 to 204984, and the like.

  The tensionless type film heating type image heating apparatus uses an endless belt-shaped or cylindrical heat-resistant film as a heating member (flexible member). The film is an apparatus in which at least a part of the circumference of the film is always tension free, and the film is rotationally driven by the rotational driving force of the pressure member.

  Reference numeral 32 denotes a stay as a heating body supporting member / film guide member. This stay 32 is a horizontally long rigid member made of heat-resistant resin that is long in the longitudinal direction, and is formed in a substantially semicircular saddle shape in cross section. In this embodiment, a highly heat-resistant liquid crystal polymer is used as the material (material) of the stay 32. Both ends of the stay 32 are held by side plates of an apparatus frame (not shown).

  Reference numeral 1 denotes a heater as a heating body, which is fitted in a groove 32 a provided on the lower surface of the stay 32 along the longitudinal direction of the stay 32. The heater 1 will be described in detail in the next section (3).

  A cylindrical film 33 having excellent heat resistance as a heating member (flexible member) is loosely fitted around the outer periphery of the stay 32. The film 33 has a total thickness of about 100 μm or less in order to reduce the heat capacity and improve the quick start property. As a specific example of the film 33, a single layer of PTFE, PFA, FEP having heat resistance, releasability, strength, durability and the like can be used. Alternatively, a composite layer film in which PTFE, PFA, FEP or the like is coated on the outer peripheral surface of polyimide, polyamideimide, PEEK, PES, PPS or the like can be used. In this example, a film having a thickness of 60 μm obtained by coating a 10 μm thick PTFE on a 50 μm thick polyimide film was used as the film 33. The inner peripheral surface side of the film 33 is coated with grease in order to improve slidability.

  Reference numeral 40 denotes an elastic pressure roller as a pressure member (backup member). The pressure roller 40 has an insulating property such as a silicone solid rubber or a silicone sponge rubber as an elastic layer on a metal shaft 41 made of a metal such as iron or aluminum, or a conductivity obtained by dispersing a conductive agent. The elastic layer 42 is formed. A fluororesin layer is formed thereon as the release layer 43. The pressure roller 40 is a horizontally long member that is long in the longitudinal direction, and both longitudinal ends of the cored bar 41 are rotatably held on the side plate of the apparatus frame via bearing members (not shown). . The pressure roller 40 is pressed by a pressure spring (not shown) so that the outer peripheral surface (surface) of the pressure roller 40 is in contact with the outer peripheral surface (surface) of the film 33 with a pressure of about 127 N (13 kgf). Has been. That is, a predetermined pressure is applied between the heater 1 and the pressure roller 40 (precisely between the stay 32 holding the heater 1 and the pressure roller 40), so that the space between the heater 1 and the pressure roller 40 is increased. A nip portion (fixing nip portion) N having a predetermined width is formed with the film 33 interposed therebetween.

  When the driving force of the rotation driving mechanism M is transmitted to the driving gear G provided at the end of the metal core 41 of the pressure roller 40, the pressure roller 40 is rotated at a predetermined peripheral speed in the arrow direction. Due to the rotation of the pressure roller 40, a rotational force acts on the film 33 by the frictional force between the surface of the pressure roller 40 and the surface of the film 33 at the nip portion N. The inner surface of the film 33 is in contact with the surface of the heater 1 (the surface of the substrate 2 described later) in the nip portion N and slides around the stay 32 in the direction of the arrow substantially the same as the rotational speed of the pressure roller 40. Followed by speed. The stay 32 also serves as a guide member for the film 33 that is driven to rotate.

  The recording material P carrying the toner image t between the film 33 and the pressure roller 40 in a state where the temperature of the heater 1 rises to a predetermined fixing temperature and the rotational peripheral speed of the film 33 is steady is fixed to the fixing inlet guide 45. Introduced along. Then, when the recording material P is nipped and conveyed together with the film 33 at the nip portion N, the heat of the heater 1 is applied to the recording material P through the film 33 and an unfixed toner image t on the recording material P is recorded. Heat-fixed on the surface of the material P. The recording material P that has passed through the nip portion N is separated from the surface of the film 33 and conveyed to the conveying roller 23.

(3) Heating body (heater) 1
5A is an explanatory diagram of the configuration of the heater 1, the temperature control system, the power supply members 3a and 3b, and the recording material conveyance reference, and FIG. 5B is a diagram illustrating the contact state between the substrate 2 of the heater 1 and the power supply member 3a. It is.

  The heater 1 has an elongated substrate 2 in the longitudinal direction. As the substrate 2, a conductive ceramic mainly composed of β-type (cubic) SiC was used. Specifically, manufactured by Bridgestone Corporation, trade name: Pure Beta-R, volume resistance value: about 0.1 Ω · cm by a four-probe method, resistance temperature coefficient: in the range from 25 ° C to 300 ° C- 3000 ppm / K was used. The dimensions of the substrate 2 are a thickness of 1 mm, a width of 6 mm, and a length of 216 mm.

  Reference numerals 3 a and 3 b denote power supply members held at both ends in the longitudinal direction of the stay 32. As the power supply members 3 a and 3 b, bent SUS plates are brought into contact with the longitudinal end faces 2 a and 2 b of the substrate 2 at both longitudinal ends of the substrate 2. That is, the power feeding members 3 a and 3 b sandwich and fix the substrate 2 while pressing the longitudinal end surfaces 2 a and 2 b at both ends in the longitudinal direction of the substrate 2 in the longitudinal direction of the substrate 2. Therefore, the power supply member is in contact with the longitudinal end surfaces 2 a and 2 b which are surfaces of the substrate 2 at both longitudinal ends of the substrate 2.

  When the heater 1 is energized from the commercial power source (AC power source) 54 through the AC power source control circuit (triac) 53 to the power supply members 3a and 3b, the entire substrate 2 generates heat and quickly rises in temperature. That is, the heater 1 is energized through the path of the AC power source 54 → the power supply member 3 a → the substrate 2 → the power supply member 3 b, and the substrate 2 generates heat. A thermistor 50 as temperature detecting means is disposed on the back surface opposite to the front surface (film sliding surface) of the substrate 2. The thermistor 50 detects the temperature state of the heater 1. The temperature information of the thermistor 50 is taken into the control circuit (CPU) 52 as the control means through the A / D converter 51. The CPU 52 controls the power supply to the heater 1 by performing phase control, wave number control, etc. on the AC voltage supplied from the triac 53 to the heater 1 based on the temperature information from the thermistor 50, thereby controlling the heater 1 to a predetermined fixing temperature (target Temperature).

  Here, the paper width is a recording material dimension in a direction orthogonal to the recording material conveyance direction X on the surface of the recording material P. In the printer of this embodiment, the center in the width direction of the recording material is used as a transport reference, and the center in the longitudinal direction of the heater 1 of the fixing device 22 is a transport reference for recording materials P of various sizes. In FIG. 5A, O is the recording material conveyance reference line (virtual line). A is a sheet passing portion (maximum sheet passing area) of a recording material having a fixed maximum sheet width that can be used in this printer, and is equal to the length of the substrate 2 of the heater 1. B is a sheet passing portion (minimum sheet passing area) of a recording material having a fixed minimum sheet width that can be used in the printer. C is a non-sheet passing portion (non-sheet passing region) generated in the nip portion N in the longitudinal direction of the heater 1 when a recording material (small size paper) having a smaller paper width than the recording material having the maximum paper width is passed. The area width of the non-sheet passing portion C varies depending on the size of the sheet width of the small size sheet that has been passed.

  The thermistor 50 for detecting the temperature of the heater 1 is provided in a minimum sheet passing area that is a recording material passing area, that is, an area corresponding to the sheet passing portion B, regardless of whether a recording material having a large or small paper width is passed. Yes. The reason why SiC is used as the material (material) of the substrate 2 of the heater 1 is that the resistance value decreases as the temperature rises, that is, the NTC (Negative Temperature Coefficient) characteristic is used, and the non-sheet-passing portion C of the heater 1 is excessive. This is to suppress the temperature rise. Accordingly, the substrate 2 has a characteristic that the resistance decreases as the temperature of the substrate 2 increases in a temperature range equal to or lower than the maximum substrate temperature. Here, the maximum substrate temperature is 300 ° C.

  Next, the reason why the excessive temperature rise in the non-sheet passing portion C can be reduced by using the heater 1 made of the NTC characteristic substrate 2 will be described with reference to FIG.

FIG. 6 is a model diagram of the heater 1. When the current flowing through the substrate 2 of the heater is I, the resistance value of the sheet passing portion of the heater 1 is R1, and the resistance value of one side of the non-sheet passing portion is R2, the heat generation amount W1 of the sheet passing portion is I ² · R1 The calorific value W2 of the non-sheet passing portion is I ² · R2. For the sake of simplicity, the position where R1 = 2 × R2 in a state where the recording material P is not passed (introduced) into the nip portion N, that is, the length of the non-sheet passing portion (the length of the non-sheet passing portion on both sides). Let us consider dividing the paper passing portion and the non-paper passing portion at a position where (sum) is equal to the length of the paper passing portion. Here, in a state where the recording material P is not passed through the nip portion N, the resistance value per unit length of the substrate 2 is uniform throughout the heater 1.

  Consider a case where small-size paper is passed through a fixing device equipped with a heater formed by integrally molding a substrate having the same dimensions as the substrate 2 made of a material having PTC (Positive Temperature Coefficient) characteristics. Since the film heated by the heater comes into contact with the small size paper, the heat of the sheet passing portion is taken by the width of the small size paper. The temperature of the sheet passing portion is detected by a thermistor, and energization control is performed based on the temperature information of the thermistor so that the temperature of the sheet passing portion does not decrease. For this reason, the non-sheet passing portion where the heat is not taken away by the small size paper becomes higher in temperature than the sheet passing portion. In this case, since the resistance value per unit length of the non-sheet passing portion is higher than the resistance value per unit length of the sheet passing portion due to the PTC characteristic, the heat generation amount W2 of the non-sheet passing portion on one side is the sheet passing portion. It becomes larger than the calorific value W1. That is, the amount of heat generated per unit length of the non-sheet passing portion is larger than that of the sheet passing portion. Further, since the temperature rises as the heat generation amount increases, the resistance further increases and the heat generation amount further increases.

  On the other hand, in the heater 1 having the NTC characteristic as in this embodiment, when small-size paper is passed, the resistance value is lower when the temperature is higher, so the resistance value per unit length of the non-sheet passing portion. Becomes lower than the resistance value per unit length of the sheet passing portion. Therefore, the heat generation amount W2 of the non-sheet passing portion on one side is smaller than the heat generation amount W1 of the sheet passing portion. That is, the heat generation amount per unit length of the non-sheet passing portion is smaller than that of the sheet passing portion. For this reason, heat generation at the non-sheet passing portion can be suppressed as compared with a heater having PTC characteristics.

  For the reasons described above, the NTC characteristic heater 1 can keep the temperature of the non-sheet passing portion low when passing small size paper.

In this embodiment, the material of the substrate 2 of the heater 1 is a SiC sintered body. Although SiC differs depending on the firing conditions, generally it has a large negative resistance temperature coefficient at 400 ° C. or lower, so that the temperature rise of the non-sheet passing portion of the heater 1, so-called non-sheet passing portion temperature rise is greatly increased. Can be reduced. In addition to SiC, it is also possible to use other ceramic heating elements mainly composed of LaCrO ₃ or the like as the material of the substrate 2. In the bulk heater in which the substrate 2 is integrally molded with such a ceramic heating element, the entire substrate 2 generates heat. Therefore, when the conventional connector feeding structure as shown in FIG. 7 is adopted, there are problems in the following points. there were.

  FIG. 7 is an explanatory view showing a state in which a conventional connector member is connected to the substrate 2 of the heater 1 of this embodiment.

(I) Temperature rise of the connector member 30 In FIG. 7, the connector member 30 is sandwiched and fixed between the electrode member 31 and the pressing member 32 with the end portion in the longitudinal direction of the substrate 2 of the heater 1 interposed therebetween. In such a state, when energization is performed between the electrode members 31 and 31 of the connector member 30 fixed to both ends in the longitudinal direction of the substrate 2, both ends in the longitudinal direction of the substrate 2 sandwiched between the connector members 30 are also included. Fever. For this reason, the connector member 30 may be thermally deformed, or deformation of the connector member 30 may cause the contact between the substrate 2 and the electrode member 31 to become unstable, resulting in poor conduction. In addition, since stress is applied to the substrate 2 at the contact portion between the substrate 2 and the electrode member 31 and between the substrate 2 and the pressing member 32 (the portion indicated by the broken line in FIG. 7), the thermal stress is concentrated when the temperature is raised. As a result, the substrate 2 may be damaged.

(Ii) Heater Size The connector member 30 must be installed outside the end surface in the longitudinal direction of the pressure roller 40 that is pressed against the substrate 2 of the heater 1 as a backup member (a region indicated by an arrow in FIG. 7). . Therefore, the length of the heater 1 (longitudinal size of the heater 1) needs to be equal to or longer than the length of the pressure roller 40 in the longitudinal direction. For this reason, the longitudinal size of the heater 1 is increased, leading to an increase in the cost of the heater 1.

  The fixing device 22 of this embodiment can supply power to the substrate 2 through power supply members 3a and 3b that are in contact with the longitudinal end faces 2a and 2b of the substrate 2 at both longitudinal ends of the substrate 2 of the heater 1. Accordingly, since the fixing device 22 of this embodiment does not include the connector member 30, there is no problem caused by the temperature rise of the connector member 30. That is, problems such as the temperature rise of the connector member 30, the occurrence of conduction failure due to the temperature rise of the connector member 30, and the breakage of the substrate 2 due to the temperature rise of the connector member 30 do not occur.

  Further, as shown in FIG. 5, in the fixing device 22 of this embodiment, the longitudinal end surfaces 2a and 2b of the substrate 2 are connected to the longitudinal ends of the substrate 2 by power supply members 3a and 3b at both longitudinal ends of the substrate 2 of the heater 1. It is clamped and fixed while pressing in the direction. Therefore, even when the substrate 2 expands / shrinks due to heating / cooling of the heater 1, it is possible to prevent poor conduction at the contact portion where the power supply members 3 a, 3 b are in contact with the longitudinal end surfaces 2 a, 2 b of the substrate 2. .

  Further, the fixing device 22 of the present embodiment includes the SiC heater 1 in which SiC is integrally formed in a long and narrow substrate shape. Therefore, by supplying power from the longitudinal end surfaces 2a and 2b of the substrate 2 of the heater 1, the entire longitudinal direction of the substrate 2 can be used as a heating element. Therefore, the length of the substrate 2 (the length in the longitudinal direction of the substrate 2) can be set to the same dimension as the LTR size 216 mm which is the maximum sheet passing width (recording material conveyance width) of the printer. That is, the dimension of the heater in the longitudinal direction of the substrate can be the same as the maximum width in the width direction of the recording material corresponding to the longitudinal direction of the substrate. As a result, the size of the heater 1 can be limited to the minimum necessary size in the longitudinal direction, and the heater 1 can be downsized. Therefore, the cost can be reduced by downsizing the heater 1.

[Example 2]
Another fixing device according to the present invention will be described.

  In the present embodiment, the same reference numerals are given to members and portions common to the first embodiment of the heater and the fixing device, and the description thereof is omitted. The same applies to Example 3.

  FIG. 8 is an explanatory diagram of the configuration of the heater 1 of the fixing device 22 according to the present embodiment, the power supply members 3a and 3b, the pressing members 3c and 3d, and the recording material conveyance reference.

  In the fixing device 22 shown in the present embodiment, the feeding members 3a and 3b and the pressing members 3c and 3d are brought into contact with the short-side end surfaces 2c and 2d, which are the surfaces of the substrate 2, at both longitudinal ends of the substrate 2 of the heater 1. It is configured. The fixing device 22 of the present embodiment has the same configuration as the fixing device 22 of the first embodiment except for the configuration.

  The printer equipped with the fixing device 22 of the present embodiment uses the center in the width direction of the recording material as the conveyance reference, like the printer of the first embodiment. Therefore, in FIG. 8, O is the recording material conveyance reference line (virtual line). A is a sheet passing portion (maximum sheet passing area) of a standard maximum paper width usable in this printer, and B is a sheet passing portion (minimum sheet passing width) of a standard minimum sheet width usable in this printer. Paper area). C is a non-sheet passing portion (non-sheet passing region) generated in the nip portion N in the longitudinal direction of the heater 1 when a recording material (small size paper) having a smaller paper width than the recording material having the maximum paper width is passed.

  The material of the substrate 2 of the heater 1 is the same as that of the first embodiment. The substrate 2 has a thickness of 1 mm, a width of 3 mm, and a length of 270 mm.

  The power feeding members 3 a and 3 b are held at both ends of the stay 32 in the longitudinal direction. As the power supply members 3 a and 3 b, bent SUS plates are brought into contact with the short-side end surfaces 2 c and 2 d of the substrate 2 that is in a diagonal position relative to the substrate 2 of the heater 1. That is, the power supply members 3 a and 3 b are in contact with the short-side end surfaces 2 c and 2 d of the substrate 2 at both longitudinal ends of the substrate 2. The dimension between the short-side end faces 2c and 2d in contact with the power feeding members 3a and 3b of the substrate 2 is the same as the maximum width in the width direction of the recording material corresponding to the longitudinal direction of the substrate 2. That is, the dimension between the short-side end faces 2c and 2d in contact with the power supply members 3a and 3b of the substrate 2 is the same as the maximum width in the width direction of the recording material corresponding to the longitudinal direction of the substrate 2. Further, in order to fix and support the heater 1 in the groove 32 a of the stay 32, holding members 3 c and 3 d are arranged at both ends in the longitudinal direction of the stay 32 so as to face the power feeding members 3 a and 3 b in the recording material conveyance direction X. It is set up. The holding members 3c and 3d are formed by bending a SUS plate, similarly to the power feeding members 3a and 3b. That is, the power supply members 3a and 3b and the pressing members 3c and 3d are the same in material and shape. Therefore, the power feeding members 3a and 3b can be used as the pressing member, and the pressing members 3c and 3d can be used as the power feeding member.

  The fixing device 22 according to the present embodiment energizes the substrate 2 of the heater 1 between the power supply member 3a and the power supply member 3b. In this way, by energizing between the short-side end faces 2c and 2d of the substrate 2 through the power supply members 3a and 3b that are diagonally positioned with respect to the substrate 2 of the heater 1, the entire substrate 2 is substantially uniformly distributed. Can generate heat. Therefore, since the fixing device 22 of the present embodiment also does not include the connector member 30, the problem caused by the temperature rise of the connector member 30 does not occur as in the fixing device 22 of the first embodiment.

  Further, if energization is performed between the power supply member 3a and the pressing member 3d, the amount of heat generated on the short-side end surface 2c on the upstream side in the recording material conveyance direction X of the substrate 2 is reduced in the short direction on the downstream side in the recording material conveyance direction X on the substrate 2. The amount of heat generated at the end face 2d can be made larger. Accordingly, since the heat of the substrate 2 flows from the upstream side to the downstream side of the substrate 2 in the recording material conveyance direction X when the film 33 rotates, the upstream side of the nip portion N in the recording material conveyance direction X can be set as the peak heat generation position. . As a result, the heat distribution in the nip portion N during the rotation of the film 33 can be made uniform, and in the nip portion N, the toner is always pressed against the surface of the recording material P in a state of being softened by heating and melting. Become. Therefore, the heating and fixing properties of the toner image t can be improved.

  Further, since the fixing device 22 of this embodiment has the power feeding members 3a and 3b in contact with the short-side end surfaces 2c and 2d of the substrate 2 at both longitudinal ends of the substrate 2, the width of the substrate 2 of the heater 1 is increased. The minimum width necessary for fixing the toner image t can be obtained. As a result, the size of the heater 1 can be limited to the minimum necessary size in the short direction, and the heater 1 can be downsized. Therefore, as in the first embodiment, the cost can be reduced by downsizing the heater 1.

  In the fixing device 22 of this embodiment, the feeding members 3a and 3b and the pressing members 3c and 3d are brought into contact with the short-side end surfaces 2c and 2d of the substrate 2 at both ends in the longitudinal direction of the substrate 2, and therefore the recording material. It is possible to change the heat generation distribution in the transport direction. In other words, the entire substrate 2 of the heater 1 is uniformly heated by diagonal power supply using the power supply members 3a and 3b, or upstream of the recording material conveyance direction of the substrate 2 by the same surface power supply using the power supply member 3a and the pressing member 3d. The amount of heat generated on the side can be increased. As a result, the heating and fixing properties of the toner image t can be improved.

[Example 3]
Another fixing device according to the present invention will be described.

  FIG. 9 is an enlarged perspective view of the longitudinal end of the substrate 2 of the heater 1. 10A is an explanatory diagram of the configuration of the heater 1, the temperature control system, the power supply members 3a and 3b, and the recording material conveyance reference. FIG. 10B is an example of the contact state between the substrate 2 of the heater 1 and the power supply member 3a. FIG.

  The fixing device 22 shown in this embodiment is the fixing device 22 of Embodiment 1 except that the sliding layer 7a is provided on the entire surface of the substrate 2 of the heater 1 and the insulating layer 7b is provided on the entire back surface of the substrate 2. It has the same configuration as

  The printer equipped with the fixing device 22 of the present embodiment uses the center in the width direction of the recording material as the conveyance reference, like the printer of the first embodiment. Accordingly, in FIG. 10A, O is the recording material conveyance reference line (virtual line). A is a sheet passing portion (maximum sheet passing area) of a standard maximum paper width usable in this printer, and B is a sheet passing portion (minimum sheet passing width) of a standard minimum sheet width usable in this printer. Paper area). C is a non-sheet passing portion (non-sheet passing region) generated in the nip portion N in the longitudinal direction of the heater 1 when a recording material (small size paper) having a smaller paper width than the recording material having the maximum paper width is passed.

  The material of the substrate 2 of the heater 1 is the same as that of the first embodiment. The substrate 2 has a thickness of 1 mm, a width of 6 mm, and a length of 216 mm.

  The power feeding members 3 a and 3 b are held at both ends of the stay 32 in the longitudinal direction. As the power supply members 3 a and 3 b, bent SUS plates are brought into contact with the longitudinal end surfaces 2 a and 2 b which are the surfaces of the substrate 2. That is, the power supply member is in contact with the longitudinal end surface of the substrate at both longitudinal ends of the substrate.

  The sliding layer 7a is provided for the purpose of smoothening the surface property of the surface of the substrate 2 on which the inner surface of the film 33 slides and improving the fixing property of the toner image t. The insulating layer 7 b is provided for the purpose of providing basic insulation between the back surface of the substrate 2 and the thermistor 50. Both the sliding layer 7a and the insulating layer 7b are formed of a glass coat layer.

  In the heater 1 of this embodiment in which the surface of the substrate 2 is covered with the sliding layer 7a and the back surface of the substrate 2 is covered with the insulating layer 7b, the longitudinal end surfaces 2a and 2b at both ends in the longitudinal direction of the substrate 2 are the power supply members 3a. , 3b are secured as contact points. That is, the heater 1 has a configuration in which the sliding layer 7 a and the insulating layer 7 b are not provided on the end faces 2 a and 2 b in the longitudinal direction of the substrate 2. The heater 1 is adjusted so that the resistance value between the power supply members 3a and 3b of the substrate 2 is 20Ω. Then, the feeding members 3a and 3b are in contact with the longitudinal end faces 2a and 2b of the substrate 2 at positions close to the sliding layer 7a in the thickness direction of the substrate 2 (positions indicated by broken lines in FIG. 10B). ing.

  Similarly to the fixing device 22 of the first embodiment, the fixing device 22 of the present embodiment uses the entire length in the longitudinal direction of the substrate 2 as a heating element by supplying power from the longitudinal end faces 2a and 2b of the substrate 2 of the heater 1. it can. Therefore, the fixing device 22 of the present embodiment also does not have the connector member 30, so that the problem due to the temperature rise of the connector member 30 does not occur. Further, the size of the heater 1 can be limited to the minimum necessary size in the longitudinal direction, and the heater 1 can be reduced in size. Therefore, the cost can be reduced by downsizing the heater 1.

  Further, in the fixing device 22 of this embodiment, since the power feeding members 3a and 3b are in contact with the longitudinal end faces 2a and 2b of the substrate 2 at positions close to the sliding layer 7a on the surface of the substrate 2, the sliding of the substrate 2 is performed. The amount of heat generated near the layer 7a can be increased. Thereby, the heating and fixing properties of the toner image t can be improved. On the other hand, the responsiveness of the thermistor 50 is improved by bringing the feeding members 3a and 3b into contact with the longitudinal end faces 2a and 2b of the substrate 2 in the thickness direction of the substrate 2 at positions close to the insulating layer 7b on the back surface of the substrate 2. Can be made.

[Other]
1) In each of the embodiments, the example in which the fixing device 22 is mounted on the printer that transports the recording material based on the central reference has been described. However, the fixing device 22 may be mounted on the printer that transports the recording material based on the one-side reference. .

  2) The image heating apparatus according to the present invention is not limited to the heat fixing apparatus of each embodiment, but an image heating apparatus that heats a recording material carrying an image to improve surface properties such as gloss, an image heating apparatus that is supposed to be worn, and the like It can be used as a means / apparatus for heat-treating a recording material carrying a wide image.

Configuration model diagram of an example of an image forming apparatus Cross-sectional configuration model diagram of an example of a fixing device according to Embodiment 1 Fig. 3 is a longitudinal sectional configuration model diagram of a fixing device according to the first embodiment. FIG. 3 is a diagram of the fixing device according to the first exemplary embodiment viewed from the recording material introduction side FIG. 5A is an explanatory diagram of a heater configuration, a temperature control system, a power supply member, and a recording material conveyance reference of the fixing device according to the first embodiment, and FIG. 5B illustrates a contact state between the heater substrate and the power supply member. Model diagram of heater FIG. 3 is an explanatory diagram illustrating a state where a conventional connector member is connected to a heater substrate of the fixing device according to the first embodiment. Explanatory drawing of the structure of the heater of a fixing device which concerns on Example 2, an electric power feeding member, a pressing member, and a recording material conveyance reference | standard. FIG. 6 is an enlarged perspective view of a longitudinal end portion of a substrate of a heater of a fixing device according to a third embodiment. (A) is explanatory drawing of the structure of the heater 1 of the fixing device based on Example 3, a temperature control system, a power feeding member, and a recording material conveyance reference | standard, (b) represents an example of the contact state of the board | substrate of a heater and a power feeding member. Figure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heater, 2 ... Substrate, 2a, 2b ... Longitudinal end surface of substrate, 2c, 2d ... End surface of substrate in short direction, 3a, 3b ... Feeding member, 22 ... Fixing device, 33 ... Film, 40 ... Elastic pressure roller, N ... Nip part, P ... Recording material

Claims (5)

In an image heating apparatus comprising: a heater that generates heat by energization; a power supply member that energizes the heater; and a heating member that is heated by the heater and that heats an image carried by a recording material.
The heater is an elongated substrate, and has a substrate that generates heat when energized, and the power supply member is in contact with the surface of the substrate at both longitudinal ends of the substrate. Image heating device.   The feeding member is in contact with the longitudinal end face of the substrate at both longitudinal ends of the substrate, and the longitudinal dimension of the substrate is the maximum width in the width direction of the recording material corresponding to the longitudinal direction of the substrate. The image heating apparatus according to claim 1, wherein the image heating apparatus is the same. A heater that generates heat when energized, a power supply member that energizes the heater, a heating member that moves while being in contact with the heater, and a pressure member that forms a nip portion with the heater across the heating member. In the image heating apparatus that heats the image while sandwiching and conveying the recording material that carries the image at the nip portion,
The heater has a substrate that is elongated in a direction perpendicular to the recording material conveyance direction, and the entire substrate generates heat when energized, and the power supply member has a surface of the substrate at both longitudinal ends of the substrate. An image heating apparatus that is in contact with the image heating apparatus.   The feeding member is in contact with the longitudinal end face of the substrate at both longitudinal ends of the substrate, and the longitudinal dimension of the substrate is the maximum width in the width direction of the recording material corresponding to the longitudinal direction of the substrate. The image heating apparatus according to claim 4, wherein the image heating apparatus is the same.   5. The image heating apparatus according to claim 1, wherein the substrate of the heater has a characteristic that the resistance decreases as the temperature of the substrate rises below the maximum substrate temperature. 6.