JP7014064B2 - Heater unit, fixing device and image forming device - Google Patents

Description

The present invention relates to a heater unit, a fixing device and an image forming device, and is suitable for application to, for example, an electrophotographic printer.

In recent years, as an image forming apparatus, for example, a toner (also called a developer) is used by an image forming unit to generate a toner image (also called a developer image) based on image data, and the image is transferred to paper (also called a medium). Some images are printed by applying heat or pressure to the paper by a fixing unit to fix the paper.

As the fixing portion, for example, one is known in which a heat generating roller that generates heat and a backup roller to which the heat generating roller is pressed are arranged so as to face each other on both sides of a transport path through which paper is conveyed. Among these, a heat generating roller has been proposed, for example, having a belt formed in a cylindrical shape and a heater unit that generates heat arranged so as to abut on the inner peripheral surface of the belt (see, for example, Patent Document 1). ).

The heater unit has, for example, a heater and electrodes made of heat-generating resistors, a substrate provided with a predetermined wiring pattern, and a holder for holding the substrate and the like. The holder is also provided with a connector insertion hole into which a connector to which a current is supplied is inserted. When the connector is inserted into the holder, the heater unit brings the terminal provided on the connector into contact with the electrode on the substrate. In this state, when a current is supplied from the image forming apparatus side through the electrode of the connector, the heater unit causes the current to flow through the heater to generate heat.

Japanese Unexamined Patent Publication No. 2015-191734 (FIGS. 2 and 3 etc.)

By the way, in the heater unit having such a configuration, the temperature of the substrate rises due to heat generation and expands, so that the lengths of the substrates are compared with respect to the main scanning direction (that is, the left-right direction) which is the longitudinal direction according to the change in temperature. It expands and contracts greatly. On the other hand, in the heater unit, the holder to which the connector is connected is often made of a material having a low thermal expansion rate, such as metal or a heat-resistant resin. That is, the holder of the heater unit has an extremely small amount of displacement in the main scanning direction even when a temperature change occurs.

Then, in the heater unit, the electrodes of the substrate are slid with respect to the terminals of the connector each time heat is generated and each time it is cooled, that is, every time the temperature changes. In particular, in the heater unit, as shown in FIG. 3 of Patent Document 1, when electrodes are arranged on both sides of the substrate with respect to the main scanning direction and holders are provided for each to connect the connector, at least. On the other hand, the sliding distance becomes sufficiently large.

Then, in the heater unit, every time the temperature changes, sliding occurs over a sufficiently large distance between the electrode of the substrate and the terminal of the connector, which causes the surface of the terminal and the electrode to wear and the contact state is maintained. There is a problem that it deteriorates, causes poor contact, and may not be able to supply sufficient current, that is, it may not be able to generate heat normally.

The present invention has been made in consideration of the above points, and an object of the present invention is to propose a heater unit, a fixing device, and an image forming device capable of stably supplying a current from a connector to a substrate regardless of a temperature change. ..

In order to solve this problem, in the heater unit of the present invention, the heater is provided in the heat generation range along the main scanning direction, and is electrically connected to the heater at a position distant from the heat generation range in one direction with respect to the main scanning direction. A board provided with a connector provided with a connector and a positioning unit that determines the position in the main scanning direction on one direction side of the heat generation range, and a terminal that determines the position of the substrate with respect to the main scanning direction by the positioning unit and supplies current. When a connector having a connector is inserted into a predetermined connector insertion position, a holding body is provided to hold the terminal of the connector in contact with the electrode of the substrate, and the substrate is provided in the electrode arrangement portion provided with the electrode. The electrodes are arranged side by side in the sub-scanning direction intersecting the main scanning direction on the surface of the substrate, and the retainer is provided with connector insertion points on both sides in the sub-scanning direction and inserted into the connector insertion points. The connectors are opposed to each other in the sub-scanning direction .

Further, in the fixing device of the present invention, the heating roller portion having the above-mentioned heater unit and the fixing belt that circulates around the heater unit is formed into a cylindrical shape along the main scanning direction, and the peripheral side surface is a heating roller portion. A backup roller arranged so as to be close to or in contact with the fixing belt of the above, and a housing for rotatably supporting the backup roller and supporting the heat generating roller portion are provided.

Further, in the image forming apparatus of the present invention, an image forming unit that forms a developing agent image using a developing agent and transfers the developing agent image to a predetermined medium, and the fixing device described above, which are transferred to the medium. A developer image is provided to be fixed on the medium.

According to the present invention, when the temperature of the substrate rises due to the heating of the heater and the length of the substrate in the main scanning direction expands or contracts, the substrate can be expanded or contracted with respect to the holding body centering on the positioning portion. As a result, the present invention is the same as the present invention, which occurs when the substrate expands and contracts in the main scanning direction due to a change in temperature, as compared with a configuration in which terminals are arranged on both sides of the heat generation range in the main scanning direction and connectors are connected to each. The sliding between the electrode and the terminal of the connector can be minimized, and the occurrence of poor contact due to wear can be effectively suppressed. Further, in the present invention, the distance from the positioning portion can be suppressed as compared with the case where a plurality of electrodes are arranged in a row in the main scanning direction, so that the occurrence of poor contact can be effectively suppressed.

According to the present invention, it is possible to realize a heater unit, a fixing device and an image forming device capable of stably supplying a current from a connector to a substrate regardless of a temperature change.

It is a schematic diagram which shows the structure of an image forming apparatus. It is a schematic diagram which shows the structure of an image formation unit. It is a schematic perspective view which shows the structure of the fixing part. It is a schematic sectional drawing which shows the structure of the fixing part. It is a schematic perspective view which shows the structure of the heating roller part and the backup roller. It is a schematic perspective view which shows the structure of the heating roller part. It is a schematic perspective view which shows the structure of a heater unit. It is a schematic sectional drawing which shows the structure of a heater unit. It is a schematic perspective view which shows the structure of a holder heater. It is a schematic diagram which shows the structure of a heater substrate. It is a schematic perspective view which shows the assembly of a heater unit. It is a schematic perspective view which shows the structure of a virtual heater unit.

Hereinafter, embodiments for carrying out the invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

[1. Configuration of image forming apparatus]
As shown in FIG. 1, the image forming apparatus 1 is an electrophotographic printer, and can form (that is, print) a color image on paper P as a medium. Incidentally, the image forming apparatus 1 is a single-function SFP (Single Function Printer) that does not have an image scanner function for reading a document, a communication function using a telephone line, or the like, and has only a printer function.

In the image forming apparatus 1, various parts are arranged inside the printer housing 2 formed in a substantially box shape. Incidentally, in the following description, the right end portion in FIG. 1 is the front surface of the image forming apparatus 1, and the vertical direction, the horizontal direction, and the front-rear direction when viewed facing the front surface are defined and described.

The image forming apparatus 1 is integrated and controlled by the control unit 3. The control unit 3 is wirelessly or wiredly connected to a higher-level device (not shown) such as a computer device. When the image data representing the image to be printed is given from the higher-level device and the printing of the image data is instructed, the control unit 3 executes a printing process for forming a printed image on the surface of the paper P.

A paper storage cassette 4 for storing the paper P is provided at the lowermost portion of the printer housing 2. A paper feeding unit 5 is provided above the front of the paper accommodating cassette 4. The paper feed unit 5 has a paper feed roller and a separation roller that separate a plurality of sheets P and feed out only one sheet, a transport guide that guides the paper P upward along the transport path U, and a transport path U. It is composed of equal transport rollers arranged at opposite positions.

The paper feeding unit 5 appropriately rotates each roller based on the control of the control unit 3, so that the paper P stored in the paper storage cassette 4 in a state of being integrated is picked up and conveyed one by one. It is advanced forward and upward along the transport path U by a guide and a pair of transport rollers, and is eventually turned back and upward and sent out to the rear.

A sensor 6 for detecting the transport state, size, etc. of the paper P is provided on the rear side of the paper feed unit 5 along the transport path U. The sensor 6 is a so-called optical sensor, and is arranged so as to intersect the transport path U with the detection light traveling from the light emitting unit to the light receiving unit, and supplies the detection result by the light receiving unit to the control unit 3. The control unit 3 recognizes the transport state of the paper P based on the detection result acquired from the sensor 6, and also recognizes the size of the paper P, that is, the length in the direction along the transport path U and the left-right direction (that is,). Recognize each of the approximate lengths (in the main scanning direction).

The rear side of the sensor 6 is formed along a straight line inclined so that the transport path U slightly rises rearward when viewed from the left-right direction, and the middle transport portion 7 is arranged below the straight line. There is. The middle transport unit 7 has a configuration in which a transport belt 10 made of an endless belt is stretched around a front roller 8 arranged on the front side and a rear roller 9 arranged on the rear side.

When the driving force is transmitted from the belt drive motor (not shown) to the rear roller 9, the middle transport unit 7 rotates the rear roller 9 in the direction of arrow R2, and causes the transport belt 10 to travel accordingly. At this time, the transport belt 10 advances the upper portion along the transport path U, that is, the portion stretched between the front roller 8 and the rear roller 9 in the rear-upward direction. At this time, when the paper P is delivered from the paper feeding unit 5, the middle transport unit 7 rearranges the paper P as the transport belt 10 travels with the paper P placed on the upper side of the transport belt 10. Proceed upward.

Four image forming units 11K, 11Y, 11M and 11C are arranged in order from the front side to the rear side on the upper side of the middle transport portion 7 and on the opposite side of the middle transport portion 7 with the transport path U in between. ing. The image forming units 11K, 11Y, 11M and 11C (hereinafter collectively referred to as an image forming unit 11) correspond to each color of black (K), yellow (Y), magenta (M) and cyan (C), respectively. However, only the colors are different, and they are all configured in the same way.

The image forming unit 11 as an image forming unit is composed of an image forming transfer unit 12, a toner cartridge 13, and a print head 14 as shown in a schematic side view in FIG. 2, and is arranged below the image forming unit 11. A transport belt 10 is sandwiched between the transfer roller 17 and the transfer roller 17. Incidentally, the image forming unit 11 and each component constituting the image forming unit 11 have a sufficient length in the left-right direction according to the length in the left-right direction on the paper P. For this reason, many parts are relatively long in the left-right direction with respect to the length in the front-rear direction and the up-down direction, and are formed in an elongated shape along the left-right direction.

The toner cartridge 13 contains toner as a developer, is attached above the image forming unit 12, and supplies the contained toner to the image forming transfer unit 12. The image forming transfer unit 12 is provided with a plurality of rollers and a photoconductor drum 15. Each of the rollers and the photoconductor drum 15 is formed in a columnar shape with the central axis along the left-right direction, and is rotatably supported. Further, the photoconductor drum 15 is configured so that its peripheral side surface can be charged. In the print head 14, light emitting elements made of a large number of LEDs (Light Emitting Diodes) are linearly arranged along the left-right direction which is the main scanning direction.

The image forming transfer unit 12 appropriately rotates each roller and rotates the photoconductor drum 15 in the direction of arrow R1 by supplying a driving force from a motor (not shown). Further, the print head 14 emits light in a light emission pattern based on an image data signal supplied from the control unit 3 (FIG. 1), sequentially exposes the peripheral side surface of the photoconductor drum 15, and the irradiated light causes the photoconductor drum 15 to emit light. An electrostatic latent image is formed on the peripheral side surface of the. Subsequently, the image forming transfer unit 12 forms a toner image (hereinafter, also referred to as a developer image) corresponding to the electrostatic latent image by adhering a toner (developer) to the peripheral side surface of the photoconductor drum 15. By rotating the photoconductor drum 15, the portion where the toner image is formed is brought to the vicinity of the lower end.

When the paper P is transported along the transport path U by the transport belt 10, the image forming unit 11 sandwiches the transport belt 10 and the paper P between the photoconductor drum 15 and the transfer roller 17 to obtain a toner image. Is transferred to the paper P from the peripheral side surface of the photoconductor drum 15. In this way, each image forming unit 11 sequentially transfers and superimposes toner images of each color on the paper P transported from the front along the transport path U, and advances the images backward.

A fixing portion 18 is provided near the rear end of the middle transport portion 7. The fixing portion 18 applies heat and pressure to the paper P by two rollers arranged so as to face each other across the transport path U to fix the toner image on the paper P (details will be described later), and further rearward. Hand over to.

A paper ejection portion 19 is arranged behind the fixing portion 18. Like the paper feeding unit 5, the paper ejection unit 19 is composed of a combination of a guide for guiding the paper P, a plurality of transport rollers, and the like. The paper ejection unit 19 appropriately rotates each transport roller according to the control of the control unit 3 to transport the paper P delivered from the fixing unit 18 backward and upward, and then fold it forward to obtain the printer housing 2. Discharge to the discharge tray 2T formed on the upper surface.

[2. Configuration of fixing part]
Next, the configuration of the fixing portion 18 will be described. As shown in FIG. 3 and a schematic cross-sectional view in FIG. 4, the fixing portion 18 as a fixing device is roughly divided into a housing 21 and a transport path U formed so as to surround the whole. It is composed of a heat generating roller portion 22 arranged on the upper side and a backup roller 23 arranged on the lower side of the transport path U.

[2-1. Housing configuration]
The housing 21 (FIG. 3) has a rectangular parallelepiped shape as a whole, and the heat generating roller portion 22 and the backup roller 23 are incorporated in the portions largely hollowed out so as to penetrate the central portions of the front and rear surfaces thereof in the front-rear direction. There is. Further, on the left and right side surfaces of the housing 21, a plurality of holes such as an insertion hole for inserting a part of the heat generating roller portion 22 and a shaft hole for rotatably supporting the backup roller 23 are appropriately formed. ing.

In addition to this, on both the left and right side surfaces of the housing 21, heat-generating roller portion rotation center holes 31 formed of round holes penetrating in the left-right direction are bored in the vicinity of the front end at substantially the center in the vertical direction. A heating roller portion rotating shaft 24 is inserted into the heat generating roller portion rotating center hole 31 on each of the left and right sides. Each heating roller portion rotating shaft 24 is formed in a columnar shape along the central axis in the left-right direction, and its diameter is slightly shorter than the hole diameter of the heating roller portion rotating center hole 31 and is in the left-right direction. The length is short enough.

Further, on both left and right side surfaces of the housing 21, camshaft shaft holes 32 formed of round holes penetrating in the left-right direction are provided in the vicinity of the upper end on the rear side. A camshaft 25 is inserted through the camshaft shaft hole 32. The camshaft 25 has an elongated columnar shape along the central axis in the left-right direction, and is rotatably supported by the camshaft shaft hole 32. That is, the camshaft shaft hole 32 functions as a shaft hole that rotatably supports the camshaft 25.

A cam 26 is attached to the cam shaft 25 slightly inside the left and right side plates of the housing 21. The cam 26 is formed in a flat and distorted columnar shape with the central axis along the left-right direction, is penetrated in the left-right direction by the camshaft 25 at a position slightly off the center, and rotates integrally with the camshaft 25. It is supposed to get. That is, when the cam 26 regards the rotation center of the cam shaft 25 as the central axis, the distance from the central axis to the peripheral side surface is not uniform. For convenience of explanation, in the following, the portion of the cam 26 having the longest radius and its vicinity will be referred to as a major axis portion 26A, and the portion having the shortest radius and its vicinity will be referred to as a minor axis portion 26B.

Incidentally, a gear (not shown) is attached to the right end of the camshaft 25. In this gear, a driving force from a motor (not shown) is transmitted via a plurality of gears (not shown) attached to the right side of the housing 21. Therefore, when the motor rotates and the driving force is transmitted to the camshaft 25, the fixing portion 18 can rotate the cam 26 integrally with the camshaft 25.

Further, a spring mounting portion 33 is provided in front of the cam 26 in the housing 21. A spring 28 is attached to the spring attachment portion 33. The spring 28 is a coil spring spirally wound around a virtual winding shaft substantially along the front-rear direction, and its front end portion is fixed to a spring mounting portion 33 of the housing 21.

The rear end of the spring 28 reaches the rear side of the front end portion of the cam 26 in its natural length. Therefore, for example, when a forward force is applied to the vicinity of the rear end and the spring 28 is compressed, the rear end is positioned on the front side of the front end portion of the cam 26, and the restoring force acts on the rear end portion of the spring 28. A backward urging force can be applied.

Further, a wiring relay portion 34 is attached to the lower part of the left side surface of the housing 21 (FIG. 3). A plurality of connection slots (not shown) for connecting a plurality of connectors are appropriately formed on the upper surface and the lower surface of the wiring relay unit 34. Each connection slot is formed in a shape suitable for each connector, and a slot-side terminal that is electrically connected to a connector-side terminal provided in each connector is also appropriately arranged.

On the lower surface side of the wiring relay unit 34, for example, a main body connection slot (not shown) for electrically connecting to the printer housing 2 of the image forming apparatus 1 is provided, and the printer housing 2 is provided with a main body connection slot (not shown). The main body side connector (not shown) attached to the tip of the laid cable (not shown) is inserted and electrically connected.

Further, on the upper surface side of the wiring relay unit 34, a heat generation roller connection slot for electrically connecting to the heat generation roller unit 22 is provided, and the relay connector 35 is inserted. Four cables 36 are connected to the relay connector 35. Two of these cables 36 are connected to the connector 37 on the rear side. The remaining two cables 36 are connected to the connector 38 on the front side. As will be described later, the connectors 37 and 38 are inserted into the holder connector 66, which is a part of the heat generating roller portion 22, and are electrically connected to each other.

[2-2. Configuration of heating roller and backup roller]
The heating roller unit 22 is roughly divided into a heater unit 41 and heating rollers attached to the vicinity of both left and right ends of the heater unit 41, as shown in FIG. 5 for a schematic perspective view and FIG. 6 for an exploded perspective view. It is composed of holders 42L and 42R, a fixing belt 43, and belt guides 44L and 44R that support the fixing belt 43.

The heater unit 41 is formed in a rectangular parallelepiped shape that is long in the left-right direction as a whole, and the connectors 37 and 38 (FIG. 3) described above are connected to the front and rear near the left end, respectively. When a current is supplied to the heater unit 41 via a cable connected to this connector, the lower surface of the heater unit 41 generates heat (details will be described later).

The heat generating roller holder 42L is formed in a thin plate shape in the left-right direction as a whole, and is formed in a trapezoidal shape in which the lower base is longer than the upper base. The heat-generating roller holder 42L is manufactured, for example, by subjecting a steel plate having a sufficient thickness to a predetermined cutting process, bending process, or the like. Further, the heat generating roller holder 42L is formed at a position slightly lower in the center in the front-rear direction so that a heater insertion hole 51, which is a square hole for inserting the heater unit 41, penetrates in the left-right direction. A rotation center hole 52, which is a rotation center of the heat generating roller portion 22, is formed on the front lower side of the heater insertion hole 51.

A cam urging portion 53 having a flat rear side is formed on the rear upper side of the heat generating roller holder 42L, and a spring formed by a plurality of protrusions protruding forward on the front side of the cam urging portion 53. The receiving portion 54 is erected. Further, a mounting plate 55 for mounting on the heater unit 41 is provided on the upper side of the heater insertion hole 51 in the heat generating roller holder 42L.

The fixing belt 43 is an endless belt made of a material having flexibility and heat resistance, and is formed in a cylindrical shape with a central axis along the left-right direction.

The belt guide 44L is formed in a columnar shape with the central axis along the left-right direction as a whole, and the length in the left-right direction is sufficiently shorter than the length in the front-rear direction and the up-down direction, that is, the belt guide 44L is formed flat. ing. Incidentally, the belt guide 44L is made of, for example, a heat-resistant resin material.

The diameter of the belt guide 44L is sufficiently larger than the diameter of the fixing belt 43 in the pedestal portion 56 that occupies a portion of about 1/3 on the left side. Further, the diameter of the belt guide 44L is slightly shorter than the diameter (inner diameter) inside the fixing belt 43 at the guide portion 57 occupying a portion on the right side of about 2/3. Further, in the belt guide 44L, the heater insertion hole 58, which is a square hole for inserting the heater unit 41, penetrates in the left-right direction at a position lower than the substantially center in the vertical direction at the substantially center in the front-rear direction. It is drilled in. The heat-generating roller holder 42R and the belt guide 44R are configured to be substantially symmetrical with the heat-generating roller holder 42L and the belt guide 44L, respectively.

In the manufacturing process of the heating roller portion 22, the belt guide 44L is attached to the right side surface of the heating roller holder 42L so that the positions of the heater insertion hole 58 and the heater insertion hole 51 are aligned with each other, and the belt guide 44R is attached. It is attached to the left side surface of the heat generating roller holder 42R.

Next, in the heat-generating roller section 22, the heat-generating roller holder 42L, the fixing belt 43, and the heat-generating roller holder 42R are sequentially inserted into the pre-assembled heater unit 41 (details will be described later). At this time, the vicinity of the left end of the fixing belt 43 is inserted into the guide portion 57 of the belt guide 44L, and the vicinity of the right end thereof is inserted into the guide portion 57 of the belt guide 44R. On the heat generating roller portion 22, the heat generating roller holders 42L and 42R are fixed to the heater unit 41 via the mounting plate 55, respectively. As a result, the fixing belt 43 can rotate along the guide portions 57 of the belt guides 44L and 44R, that is, rotate around the heater unit 41, for example, when an external force toward the lower end is applied to the vicinity of the lower end.

On the other hand, the backup roller 23 (FIG. 5) is configured around a columnar roller main body 23A whose central axis is aligned in the left-right direction. The diameter of the roller main body 23A is slightly shorter than the diameter of the fixing belt 43 in the heat generating roller portion 22. Further, on the left and right side surfaces of the roller main body 23A, a rotating shaft 23B having a columnar shape thinner than the roller main body 23A is erected at the center thereof.

Further, a gear (not shown) is attached to the rotation shaft 23B on the right side in the vicinity of the tip thereof. This gear is a predetermined gear (not shown) from a predetermined motor (not shown) provided in the printer housing 2 with the fixing portion 18 mounted in the printer housing 2 (FIG. 1). ) Is used to transmit the driving force.

[2-3. Assembling the fixing part]
In the fixing portion 18 (FIGS. 3 and 4 (A)), a heat generating roller portion 22 preassembled at the time of manufacture is incorporated in the inner upper side of the housing 21, and further, on both the left and right sides, the heat generating roller portion rotation center holes are formed. The heat generating roller portion rotating shaft 24 is inserted into the 31 and the rotating center hole 52, respectively. Incidentally, at both ends of the heat generating roller portion rotating shaft 24, retaining members for preventing the heat generating roller portion from coming off from the rotating center hole 31 and the rotating center hole 52 are attached, respectively. As a result, the fixing portion 18 can rotate the heat generating roller portion 22 with respect to the housing 21 around the heat generating roller portion rotation center hole 31.

Further, in the fixing portion 18, the backup roller 23 is incorporated in the inner lower side of the housing 21, that is, the lower side of the heat generating roller portion 22, and the rotating shaft 23B is inserted into a predetermined shaft hole on both the left and right sides so as to be rotatable. Be supported. At this time, in the fixing portion 18, the rotation range of the heating roller portion 22 is limited by the presence of the backup roller 23, and as a result, the cam urging portions 53 of the heating roller holders 42L and 42R are left and right in the housing 21. It is located in front of the virtual straight line connecting the camshaft shaft holes 32 to each other.

Further, in the fixing portion 18, the camshaft 25 to which the cam 26 is attached is inserted into the camshaft shaft hole 32 on both the left and right sides of the housing 21. As a result, in the fixing portion 18, the cam urging portion 53 of the heat generating roller portion 22 is located on the front side of the cam 26 on both the left and right sides.

Further, in the fixing portion 18, the spring 28 is shortened from the natural length, the rear ends of the spring 28 are attached to the spring mounting portions 33 on both the left and right sides of the housing 21, and the front ends of the spring 28 are the heat generating roller portions 22. It is inserted through the spring receiving portion 54. That is, in the fixing portion 18, the spring 28 is sandwiched between the spring mounting portion 33 of the housing 21 and the spring receiving portion 54 of the heat generating roller portion 22 in a compressed state from the natural state.

In the fixing portion 18, the restoring force of the spring 28 causes the spring receiving portion 54 to be urged backward against the spring mounting portion 33 fixed to the housing 21. As a result, in the fixing portion 18, the heating roller portion 22 is rotated around the heating roller portion rotating shaft 24, and the fixing belt 43 and the heater unit 41 are brought close to the backup roller 23.

Here, in the fixing portion 18, when the short diameter portion 26B of the cam 26 faces forward, as shown in FIG. 4A, the cam urging portion 53 urged rearward by the restoring force of the spring 28. Is pressed against the roller main body 23A of the backup roller 23 via the fixing belt 43 before the heater unit 41 of the heat generating roller portion 22 comes into contact with the cam 26. Hereinafter, such a state is referred to as a nip state or a pressed state.

When the backup roller 23 rotates in the direction of arrow R4 in this nip state, the fixing portion 18 exerts a frictional force with the fixing belt 43 of the heat generating roller portion 22 and rotates the fixing belt 43 in the direction of arrow R3 (circling). ) Can be made. At this time, if the paper P is transported along the transport path U, the fixing portion 18 can apply heat and pressure to the paper P.

On the other hand, in the fixing portion 18, when the major axis portion 26A of the cam 26 faces forward, the cam 26 abuts on the cam urging portion 53 of the heating roller portion 22 to cause the heating roller portion 22 from the backup roller 23. Slightly away, the fixing belt 43 and the heater unit 41 are separated from the roller main body 23A of the backup roller 23. Hereinafter, such a state is referred to as a non-nip state or a separated state.

In this way, in the fixing portion 18, by rotating the cam 26 and directing either the long diameter portion 26A or the short diameter portion 26B to the front, the heat generating roller portion 22 (that is, the fixing belt 43, the heater unit 41, and the backup roller 23 The roller body 23A, etc.) can be switched between a nip state and a non-nip state. For convenience of explanation, in the following, a mechanism for switching the heating roller portion 22 to the nipped state or the non-nip state in the fixing portion 18, that is, the heating roller portion rotating shaft 24, the cam 26 spring 28, the cam urging portion 53, and the spring. The receiving unit 54 and the like are collectively referred to as a state switching unit 30.

[3. Heater unit configuration]
The heater unit 41 is roughly divided into a heater support member 61, a holder heater 62, a support plate 63, a heater substrate 64, a heat diffusion member 65, and a holder connector, as shown in an exploded perspective view in FIG. 7 and a sectional view in FIG. It is composed of 66. Further, the connectors 37 and 38 are inserted into the holder connector 66, respectively. For convenience of explanation, FIG. 7 shows the heater unit 41 shown in FIG. 6 rotated half a turn in a horizontal plane, that is, rotated 180 degrees around a virtual rotation axis along the vertical direction, and then disassembled. It shows a state where the heater unit 41 is viewed from diagonally upper side in the rear right direction.

[3-1. Heater support member]
The heater support member 61 is composed of an upper plate portion 71 located on the upper side, a rear plate portion 72 located on the rear side, and a front plate portion 73 located on the front side. That is, the heater support member 61 is formed as a hollow square columnar that is elongated in the left-right direction as a whole and has an open lower surface. In the heater support member 61, for example, after a steel plate having a sufficient thickness is cut into a predetermined shape, the connecting portion of the upper plate portion 71 and the rear plate portion 72 and the connecting portion of the upper plate portion 71 and the front plate portion 73 are formed. Manufactured by bending each. Therefore, the heater support member 61 has sufficient rigidity.

The upper plate portion 71 is formed in the shape of a rectangular plate that is long in the left-right direction, short in the front-rear direction, and thin in the up-down direction. A round hole (not shown) penetrating in the vertical direction is appropriately formed in the upper plate portion 71 at a predetermined location.

The rear plate portion 72 is formed in the shape of a rectangular plate that is long in the left-right direction, short in the vertical direction, and thin in the left-right direction, and is vertically hung from the rear side of the upper plate portion 71 downward. A notch 72A cut out in a rectangular shape toward the right is formed at a position slightly distant from the lower end on the left side of the rear plate portion 72. Further, on the slightly left side from the right end on the lower side of the rear plate portion 72, a notch portion 72B notched upward in a rectangular shape is formed. A convex portion 72C protruding to the left is formed in the vicinity of the lower end of the right side of the notch 72B, and a concave portion 72D cut to the right is formed on the upper side of the convex portion 72C.

The front plate portion 73 is configured to be substantially symmetrical with the rear plate portion 72. That is, the front plate portion 73 is provided with the notch portion 72A, the notch portion 72B, the convex portion 72C and the concave portion 72D corresponding to the notch portion 73A, the notch portion 73B, the convex portion 73C and the concave portion 73D of the rear plate portion 72, respectively. ..

Further, in the vicinity of the left end of the upper plate portion 71, a portion protruding to the left of the left ends of the rear plate portion 72 and the front plate portion 73 is the upper plate protruding portion 74. The upper plate protruding portion 74 is provided with a hole portion 75 having a round hole penetrating in the vertical direction at a portion substantially centered in the front-rear direction and the left-right direction. The hole 75 has a spiral groove engraved on the inner peripheral surface thereof, and a so-called female screw is formed.

Further, the upper plate protruding portion 74 is provided with protruding portions 76 and 77 protruding upward by a predetermined protrusion amount from the surroundings on the left side and the right side of the hole portion 75. The protrusions 76 and 77 are formed in a small columnar shape along the central axis in the vertical direction. Incidentally, the protrusions 76 and 77 are formed by subjecting the plate-shaped steel plate forming the upper plate protrusion 74 to a so-called embossing process at the time of manufacture thereof.

[3-2. Holder heater configuration]
As shown in the perspective views in FIGS. 7 and 9, the holder heater 62 is formed in an elongated square columnar shape as a whole along the left-right direction. The holder heater 62 is manufactured, for example, by molding a heat-resistant resin material. Incidentally, FIG. 9 shows a state in which the holder heater 62 of FIG. 7 is rotated half a turn about a virtual rotation axis along the front-rear direction, and the holder heater 62 is viewed from diagonally lower side in the left front direction.

As shown in FIG. 8, the holder heater 62 has a cross-sectional shape similar to that of the English capital letter “H” as a whole. Specifically, the holder heater 62 has a configuration in which the rear plate portion 82 and the front plate portion 83 are connected to the front side and the rear side of the substrate portion 81 arranged slightly below the center, respectively. Further, a left plate portion 84 and a right plate portion 85 are connected to the left side and the right side of the substrate portion 81, respectively.

The substrate portion 81 is formed as a plate that is long in the left-right direction, short in the front-rear direction, and thin in the up-down direction as a whole. The upper surface and the lower surface of the substrate portion 81 are configured to be substantially flat. Further, the substrate portion 81 is located inside the rear end and the front end of the substrate central portion 81A occupying the central portion in the front-rear direction on the lower surface, that is, inside the portions connected to the rear plate portion 82 and the front plate portion 83, from the vicinity of the left end to the vicinity of the right end. A rear groove portion 81B and a front groove portion 81C that are recessed upward are formed over a long range along the left-right direction of the above. In other words, on the lower surface of the substrate portion 81, the substrate central portion 81A projects downward with respect to the rear groove portion 81B and the front groove portion 81C.

The lower surface of the substrate central portion 81A is located slightly above the lower ends of the rear plate portion 82 and the front plate portion 83. Incidentally, a columnar screw receiving column (not shown) is erected at a predetermined position on the upper surface of the substrate portion 81. A screw hole made of a round hole is formed in the center of the upper surface of the screw receiving column.

The rear plate portion 82 is formed as a plate that is long in the left-right direction, short in the vertical direction, and thin in the front-rear direction as a whole. On the rear side surface of the rear plate portion 82, the rear upper portion 82A formed in a range of about 4/5 of the upper side is formed substantially flat, and the rear lower portion 82B formed of the lower portion of the rear upper portion 82A is the rear upper portion 82A. It protrudes backward. Incidentally, the amount of protrusion of the rear lower portion 82B with respect to the rear upper portion 82A is larger than the thickness of the rear plate portion 72 of the heater support member 61.

Further, the length of the rear lower portion 82B in the left-right direction is shorter than that of the rear upper portion 82A. That is, the left end of the rear lower portion 82B is located on the right side of the left end of the rear upper portion 82A. The right end of the rear lower portion 82B is located on the left side of the right end of the rear upper portion 82A.

A protrusion 82C protruding rearward from the periphery is provided in the lower part of the rear upper portion 82A near the left end. The protruding portion 82C is formed as a whole in a rectangular shape that is long in the left-right direction and short in the up-down direction. Further, in the vicinity of the right end of the lower side of the rear upper portion 82A, a protruding portion 82D protruding rearward from the surroundings is provided. The protrusion 82D is formed in a shape that advances upward from the lower portion 82B and further bends to the right, that is, a shape that is a half-turn of the English capital letter “L”.

Further, an engaging portion 82E (FIG. 7) is provided on the left side and the front side of the rear lower portion 82B in the rear plate portion 82, that is, the left end of the rear groove portion 81B in the substrate portion 81 and on the right side of the left plate portion 84. There is. The engaging portion 82E has a length in the vertical direction shorter than the length in the horizontal direction and is formed in a thin plate shape in the front-rear direction, and an engagement hole 82EH formed of a square hole penetrating in the front-rear direction is formed. ing. The height of the upper side of the engaging hole 82EH is substantially the same as the lower surface of the substrate central portion 81A in the substrate portion 81.

Further, on the lower portion of the right side surface of the engaging portion 82E (FIG. 9), an engaging projection 82F protruding to the right from the upper portion is provided. The engaging projection 82F forms a relatively narrow gap with the upper side surface (that is, the bottom surface) of the rear groove portion 81B. On the other hand, the right side and the front side of the rear lower portion 82B in the rear plate portion 82, that is, the right end of the rear groove portion 81B in the substrate portion 81 is closed by the lower end portion of the right plate portion 85. An engaging projection 82G protruding to the left from the upper portion is provided on the lower portion of the left side surface of the right plate portion 85. The engaging projection 82G forms a relatively narrow gap with the bottom surface of the rear groove portion 81B.

The front plate portion 83 is configured to be substantially symmetrical with the rear plate portion 82. That is, the front plate portion 83 has the rear upper portion 82A, the rear lower portion 82B, the protrusion portions 82C and 82D, and the front upper portion 83A, the front lower portion 83B, and the protrusion portions 83C and 83D corresponding to the engaging protrusions 82F and 82G, respectively. , And engaging protrusions 83F and 83G, respectively. However, the front plate portion 83 is provided with a protrusion support 83E instead of the engaging portion 82E. The protrusion support 83E is a position where the engaging portion 82E is projected forward, that is, the left side and the rear side of the front lower portion 83B, the left end of the front groove portion 81C in the substrate portion 81, and the right side of the left plate portion 84. It is provided in. The protrusion support 83E is formed in a rectangular parallelepiped shape having a length in the vertical direction shorter than that of the engaging portion 82E, and the engaging protrusion 83F is provided on the lower side on the right side surface thereof. The engaging protrusion 83F is configured to be substantially symmetrical with the right engaging protrusion 83G.

The left plate portion 84 is formed in a thin plate shape in the left-right direction, and is connected to the left side of the rear plate portion 82 and the left side of the front plate portion 83, respectively. The upper side of the left plate portion 84 has the same height as the lower sides of the rear plate portion 82 and the front plate portion 83. Further, the lower side of the left plate portion 84 has the same height as the lower surface of the substrate central portion 81A of the substrate portion 81. Further, the right plate portion 85 is configured to be substantially symmetrical with the left plate portion 84.

By the way, in the holder heater 62 (FIG. 8), the distance from the rear surface of the rear upper portion 82A of the rear plate portion 82 to the front surface of the front upper portion 83A of the front plate portion 83, that is, the length in the front-rear direction in the upper portion is determined by the heater support member 61. The distance from the front surface of the rear plate portion 72 to the rear surface of the front plate portion 73, that is, slightly shorter than the inner width in the front-rear direction. Further, in the holder heater 62, the distance from the rear surface of the rear lower portion 82B in the rear plate portion 82 to the front surface of the front lower portion 83B in the front plate portion 83, that is, the length in the front-rear direction in the lower portion is determined by the rear plate portion in the heater support member 61. It is longer than the distance from the rear surface of the 72 to the front surface of the front plate portion 73, that is, the outer width in the front-rear direction.

[3-3. Configuration of support plate and heater board]
The support plate 63 (FIG. 7) is formed as a plate that is long in the left-right direction, short in the front-rear direction, and thin in the up-down direction as a whole. The length of the support plate 63 in the front-rear direction is substantially the same as the length of the holder heater 62 in the front-rear direction in the substrate central portion 81A (FIG. 8). On the other hand, the length of the support plate 63 in the left-right direction is slightly shorter than the length of the holder heater 62 in the center portion 81A of the substrate in the left-right direction. The support plate 63 is made of a metal material such as stainless steel (SUS: Steel Use Stainless).

The heater substrate 64 is formed as a whole in the shape of a plate that is long in the left-right direction, short in the front-rear direction, and thin in the up-down direction. As shown in the plan view in FIG. 10A, the heater substrate 64 is roughly divided into a heater arranging portion 91 in which the heater is arranged and an electrode arranging portion 92 in which the electrodes are arranged.

The heater substrate 64 has a thin stainless steel plate-shaped member coated with an insulating member on the lower surface thereof, and a predetermined wiring pattern, a heat generating element described later, and the like are formed, and the surface thereof is covered with a thin glass material. Therefore, the heater substrate 64 has sufficient rigidity, maintains its shape well even when an external force is applied, and suppresses the amount of bending very slightly even when bending occurs. Be done.

The heater arranging portion 91 is formed in a rectangular shape that is long in the left-right direction and short in the front-rear direction. The length in the front-rear direction of the heater arrangement portion 91 is substantially the same as the length in the front-rear direction of the substrate central portion 81A (FIG. 8) of the holder heater 62. On the other hand, the length of the heater arranging portion 91 in the left-right direction is slightly shorter than the length of the holder heater 62 in the center portion 81A of the substrate in the left-right direction. That is, the length of the heater arranging portion 91 in the left-right direction and the front-back direction is substantially the same as that of the support plate 63.

Incidentally, the length of the heater arranging portion 91 in the left-right direction is slightly longer than the length along the main scanning direction (that is, the left-right direction) in the paper P (FIG. 1). The image forming apparatus 1 can perform printing processing on a maximum A3 size paper P, and the length of the short side (that is, the left-right direction) of the paper P at this time is 297 [mm]. .. Along with this, the length of the heater arranging portion 91 in the left-right direction is slightly longer than 297 [mm]. On the other hand, the length of the heater arranging portion 91 in the front-rear direction is about 15 to 20 [mm]. The length in the front-rear direction is the front-back length of the region required for arranging the heater described later, and the front-rear length of the region for forming a wiring pattern having a line width that can supply the large current required for the heater. It is determined based on the length.

On the lower surface of the heater arranging portion 91, a heater 94 composed of five heaters is arranged along the left-right direction in a heat generation range 91A excluding the vicinity of both left and right ends. In other words, in the heater arranging unit 91, the heater 94 is arranged in each region (hereinafter, also referred to as a heat generating region) in which the heat generation range 91A is divided into five along the main scanning direction.

Specifically, in the heater arranging portion 91, the central heater 94C is arranged in a range of about 3/4 of the center in the left-right direction. Further, in the heater arranging portion 91, the left inner heater 94L1 is arranged in a range of about 1/7 adjacent to the left side of the central heater 94C, and the left outer side is arranged in a range of about 1/7 adjacent to the left side of the left inner heater 94L1. The heater 94L2 is arranged. Further, in the heater arranging portion 91, the right inner heater 94R1 is arranged in a range of about 1/7 adjacent to the right side of the central heater 94C, and the right outer side is arranged in a range of about 1/7 adjacent to the right side of the right inner heater 94R1. The heater 94R2 is arranged.

The heaters 94 (that is, the central heater 94C, the left inner heater 94L1, the left outer heater 94L2, the right inner heater 94R1 and the right outer heater 94R2) are all heat-generating resistors and are electrically isolated from each other, and each of them has a current. Is supplied, it generates heat according to the magnitude of the current.

Incidentally, the heater substrate 64 has a first heat generation state in which only the central heater 94C generates heat according to the control of the control unit 3 (FIG. 1), and in addition, a second heat generation state in which the left inner heater 94L1 and the right inner heater 94R1 generate heat. Further, in addition to these, it is possible to switch to three types of heat generation states, such as a third heat generation state in which the left outer heater 94L2 and the right outer heater 94R2 generate heat. In practice, the control unit 3 recognizes the length of the paper P in the main scanning direction (that is, the left-right direction) based on the detection result of the sensor 6 (FIG. 1), and the heater substrate 64 according to the recognized length. It is designed to switch the heat generation state in.

Further, in the vicinity of the left end of the rear side of the heater arrangement portion 91, a positioning protrusion projecting rearward is located on the left side of the left end of the heater 94, that is, on the rear side between the heat generation range 91A and the electrode arrangement portion 92. 95 is provided. The length of the positioning protrusion 95 as the positioning portion in the left-right direction is slightly shorter than the length in the left-right direction of the engagement hole 82EH of the engagement portion 82E provided in the holder heater 62.

The electrode arrangement portion 92 has a length approximately twice that in the front-rear direction (that is, the sub-scanning direction) as compared with the heater arrangement portion 91, while the length in the left-right direction (that is, the main scanning direction) is sufficiently long. It's getting shorter. Four electrodes 96 are provided on the lower surface of the electrode arrangement portion 92. Specifically, the electrode arranging portion 92 is provided with two electrodes 96A and 96B in the vicinity of the rear end edge, and two electrodes 96C and 96D are provided in the vicinity of the front end edge. Each electrode 96 (that is, electrodes 96A, 96B, 96C and 96D) is appropriately connected to the heater 94 by a wiring pattern (not shown) formed on the lower surface of the heater substrate 64.

With such a configuration, when the current is appropriately supplied from each terminal of the electrode 96, the heater substrate 64 appropriately heats each heater 94, for example, heats all the heater 94 or heats only the central heater 94C. It is possible to generate heat with a different heat generation pattern.

In other words, the heater substrate 64 is provided with the electrode arranging portion 92 only on the left side, which is one direction side in the main scanning direction (that is, the left-right direction) with respect to the heater arranging portion 91. Further, the heater substrate 64 is provided with a positioning projection 95 at a position relatively close to the electrode arranging portion 92 in the heater arranging portion 91, specifically, on the left side of the left end of the heater 94.

[3-4. Configuration of heat diffusion member]
The heat diffusion member 65 (FIG. 7) has a lower plate portion 65A formed in a rectangular shape that is long in the left-right direction and short in the front-rear direction, and a rear plate that is vertically hung upward from the front side of the lower plate portion 65A. It is composed of a portion 65B and a front plate portion 65C vertically vertically hung downward from the rear side of the lower plate portion 65A. In other words, the heat diffusion member 65 is formed as a hollow square columnar that is elongated in the left-right direction, short in the vertical direction, and has an open upper surface as a whole.

The length in the front-rear direction in the lower plate portion 65A is from the distance from the front surface of the rear lower portion 82B in the rear plate portion 82 of the holder heater 62 to the rear surface of the front lower portion 83B in the front plate portion 83, that is, the distance (inner dimension) in the front-rear direction. However, it is slightly shorter. The vertical length of the rear plate portion 65B and the front plate portion 65C is the vertical distance from the lower end of the rear lower portion 82B or the front lower portion 83B of the holder heater 62 to the bottom portion of the rear groove portion 81B and the front groove portion 81C, that is, the outside. It is substantially the same as the depth of the rear groove portion 81B and the front groove portion 81C as seen from the above. Incidentally, the length in the front-rear direction, that is, the thickness of the rear plate portion 65B and the front plate portion 65C is shorter (thinner) than the length in the front-rear direction, that is, the groove width in the rear groove portion 81B and the front groove portion 81C.

Further, in the vicinity of the upper end of the left side of the rear plate portion 65B, an engaging portion 65BP protruding to the left from the surroundings is formed. Further, in the vicinity of the upper end of the right side of the rear plate portion 65B, an engaging portion 65BQ protruding to the right from the surroundings is formed. Similarly, in the front plate portion 65C, an engaging portion 65CP and an engaging portion 65CQ are formed in the vicinity of the upper end of the left side and the vicinity of the upper end of the right side, respectively.

Further, the rear plate portion 65B has the total length in the left-right direction including each engaging portion, that is, the distance from the left end of the engaging portion 65BP to the right end of the engaging portion 65BQ in the rear groove portion 81B and the front groove portion 81C of the holder heater 62. It is slightly shorter than the length in the left-right direction, that is, the distance from the right side surface of the engaging portion 82E and the protrusion support 83E to the left side surface of the right plate portion 85.

On the other hand, the total length of the rear plate portion 65B in the left-right direction including each engaging portion is from the tip (right end) of the engaging protrusion 82F in the holder heater 62 (FIG. 9) to the tip (left end) of the engaging protrusion 82G. It is longer than the distance, that is, the distance between the engaging protrusions 82F and 82G. Further, the rear plate portion 65B has a total length in the left-right direction excluding the engaging portion, that is, the distance from the left side to the right side of the rear plate portion 65B is shorter than the distance between the engaging protrusions 82F and 82G.

By the way, the heat diffusion member 65 is manufactured, for example, by cutting a thin and flat steel plate into a long rectangular shape in the left-right direction, and further bending the portion near the front side and the portion near the rear side upward. Further, the heat diffusion member 65 can be elastically deformed when a relatively weak external force is applied due to the nature of the metal material.

Therefore, for example, when a relatively small downward external force is applied to the vicinity of the center in the left-right direction, the heat diffusion member 65 bends as a whole and bends so as to displace the vicinity of the center downward with respect to the vicinity of both left and right ends. do. At this time, the heat diffusion member 65 can have a slightly shorter apparent length in the left-right direction as compared with before bending. Further, when the external force is released, the heat diffusion member 65 can return to its original shape by the action of the elastic force.

[3-5. Holder connector configuration]
The holder connector 66 (FIG. 7) is formed in a rectangular parallelepiped shape as a whole, and a plurality of holes are appropriately formed from various directions. In this holder connector 66, particularly on the rear surface and the front surface, most of the inner side leaving the outer frame portion is a hole portion, and a part thereof penetrates in the front-rear direction. In other words, in the holder connector 66, a plurality of holes having various shapes are formed in a hollow rectangular parallelepiped whose outer shell portion is composed of a plate-shaped member, and a plurality of plate-shaped portions are further formed inside the outer shell. The members are arranged like beams and dividers.

Incidentally, the length of the holder connector 66 in the front-rear direction is longer than the length of the electrode arrangement portion 92 of the heater substrate 64 in the front-rear direction. The length of the holder connector 66 in the left-right direction is substantially the same as the length of the electrode arrangement portion 92 of the heater substrate 64 in the left-right direction.

The left side surface, the upper side surface, the right side surface, and the lower side surface of the holder connector 66 are formed of a plate-shaped left side plate 101, an upper side plate 102, a right side plate 103, and a lower side plate 104, respectively. Further, the inside of the holder connector 66 is roughly divided into three spaces such as an upper space 111, a middle space 112, and a lower space 113 by an upper partition plate 105 and a lower partition plate 106 which are plate-shaped members substantially parallel to the upper plate 102. ing.

Further, in the upper space 111, an upper center plate 107 which is a plate-shaped member substantially parallel to the left side plate 101 is provided near the center in the left-right direction. The length in the front-rear direction of the upper center plate 107 is about 60 to 70% of the length in the front-rear direction of the entire holder connector 66, and the front-rear length of the upper plate protrusion 74 of the heater support member 61 described above. It is sufficiently longer than the length in the direction.

The right side plate 103 is a central portion in the front-rear direction in the portion sandwiched between the upper plate 102 and the upper partition plate 105 (that is, near the upper end), and corresponds to a range in which the upper central plate 107 is projected to the right. In addition, a relatively large upper right hole portion 121 is formed. Further, in the central portion at the upper end of the upper central plate 107, a support member through hole 122 penetrating in the left-right direction is formed at a position directly below the upper plate 102.

The length of the support member through hole 122 in the front-rear direction is slightly longer than the length of the upper plate protrusion 74 of the heater support member 61 described above in the front-rear direction. Further, the vertical length of the support member through hole 122 is longer than the vertical length of the upper plate protruding portion 74, and the protrusion amount of the protruding portion 76 (that is, the vertical length) is set to the thickness of the upper plate protruding portion 74. It is longer than the length obtained by adding (sa).

A right heater substrate through hole 123 penetrating in the left-right direction is formed in a portion of the right side plate 103 slightly below the center in the vertical direction and directly below the lower partition plate 106. The length of the right heater substrate through hole 123 in the front-rear direction is slightly longer than the length of the electrode arrangement portion 92 of the heater substrate 64 in the front-rear direction. Further, the vertical length of the right heater substrate through hole 123 is sufficiently longer than the vertical length of the electrode arrangement portion 92 of the heater substrate 64, that is, the thickness.

The upper plate 102 is provided with a mounting hole 131 penetrating in the vertical direction at substantially the center in the front-rear direction and substantially in the center in the left-right direction. Further, the upper plate 102 is provided with a positioning hole 132 that also penetrates in the vertical direction on the left side of the mounting hole 131. Further, the upper plate 102 is formed with a positioning notch 133 cut out on the left side of the mounting hole 131 so as to enter from the right side of the upper plate 102 to the left.

The left side plate 101 has an upper left hole portion 141 and a left heater board through hole 142 at positions such that the upper right hole portion 121 of the upper center plate 107 and the right heater substrate through hole 123 of the right side plate 103 are projected to the left, respectively. Each is drilled. The upper left hole portion 141 and the left heater substrate through hole 142 are formed to have the same size as the upper right hole portion 121 and the right heater substrate through hole 123, respectively.

The lower plate 104 is a portion that is raised above the periphery, that is, recessed inside the holder connector 66, in about half on the right side of the rear half and about half on the left side of the front half. Each connector support portion 151 is formed. For convenience of explanation, the portion of the lower plate 104 excluding the connector support portion 151, that is, the two portions protruding below the connector support portion 151 are referred to as engaging portions 152, respectively. Each engaging portion 152 is provided with an engaging hole 153 having a square hole penetrating in the vertical direction.

[3-6. Connector configuration]
The connector 37 is formed in a rectangular parallelepiped shape as a whole, and its volume is about 1/3 of that of the holder connector 66. The connector 37 is formed by molding a heat-resistant resin material, and has sufficient rigidity in a portion having a sufficient thickness, while being elastic in a portion having a relatively small thickness (that is, thin). It can be transformed.

The length of the connector 37 in the front-rear direction is about 60% of the length of the holder connector 66 in the front-rear direction. Further, the vertical length of the connector 37 is slightly shorter than the length from the lower surface of the upper partition plate 105 in the holder connector 66 to the upper surface of the connector support portion 151 in the lower plate 104, except for the lock lever described later. .. Further, the length in the left-right direction of the connector 37 is slightly shorter than the length from the right side of the left side plate 101 to the left side of the right side plate 103, that is, the length in the left-right direction (inner dimension) in the central space 112 and the lower space 113. It has become.

The connector 37 has a relatively large notch 160, leaving about 1/5 from the upper end and about 70% from the rear side surface to the front in the range from the upper end to about 2/5. Is formed. As a result, the connector 37 is roughly divided into a rear base portion 161, a front lower or middle terminal holding portion 162, and a front upper upper holding portion 163. The vertical length of the notch 160, that is, the distance from the lower surface of the holding portion 163 to the upper surface of the terminal holding portion 162 is a value obtained by adding the thickness of the partition plate 106 and the thickness of the electrode arrangement portion 92 in the heater substrate 64. Is bigger than.

The vertical length of the terminal holding portion 162 is slightly shorter than the vertical length of the lower space 113 of the holder connector 66. Further, the vertical length of the holding portion 163 is slightly shorter than the vertical length of the holder connector 66 in the central space 112. Further, the vertical length of the notch 160 is slightly longer than the vertical length of the lower partition plate 106 of the holder connector 66, that is, the thickness.

Inside the terminal holding portion 162, two terminals 165 and 166 are embedded so as to be arranged along the left-right direction. The terminals 165 and 166 are made of a conductive metal material, and a part thereof is projected upward from the upper surface of the terminal holding portion 162, that is, into the notch 160. Further, the terminals 165 and 166 can be deformed downward by elastic deformation, that is, in a direction in which the amount of protrusion into the notch 160 is reduced.

On the other hand, two holes 167 and 168 are bored in the lower part of the rear surface of the base portion 161 so as to be arranged along the left-right direction. The holes 167 and 168 are square holes having a sufficient depth toward the rear, respectively. The terminals 165 and 166 are attached to and held by the terminal holding portions 162 by being attached to the tips of the cables 36 (FIG. 3) and then being inserted through the holes 167 and 168, respectively.

A lock lever 169 is provided on the left side at the lower end of the connector 37. A part of the lock lever 169 protrudes downward from the lower surface of the terminal holding portion 162, and an engaging claw 170 projecting downward from the periphery is provided on the lower surface thereof. The engaging claw 170 is formed in a substantially triangular shape when viewed from the left-right direction, and has an engaging surface facing the front side, an inclined surface facing diagonally downward and backward, and both left and right side surfaces.

Further, the lock lever 169 is integrally molded with the entire connector 37 (base portion 161 and terminal holding portion 162 and holding portion 163), and is molded relatively thinly with respect to the terminal holding portion 162 (not shown). It is connected to the terminal holding portion 162 so as to be elastically deformable with respect to the terminal holding portion 162.

The lock lever 169 is located relatively downward in a natural state where no external force is applied, and the distance (length) from the lower surface of the lock lever 169 to the upper surface of the terminal holding portion 162 is the distance (length) of the holder connector 66. It is longer than the distance (length) from the lower surface of the lower partition plate 106 to the upper surface of the engaging portion 152 in the lower plate 104.

On the other hand, when an upward external force is applied to the lock lever 169, the connection portion with the terminal holding portion 162 is elastically deformed and displaced upward. At this time, the lock lever 169 sets the distance (length) from the lower end of the engaging claw 170 to the upper surface of the terminal holding portion 162 from the lower surface of the lower partition plate 106 in the holder connector 66 to the upper surface of the engaging portion 152 in the lower plate 104. It can be shorter than the distance (length) to.

[3-7. Assembling the heater unit]
Next, the assembly of the heater unit 41 will be described. In the heater unit 41, the holder heater 62 is first attached to the heater support member 61. Specifically, in the heater unit 41, the heater support member 61 is positioned slightly to the right of the holder heater 62 directly above, and the heater support member 61 is lowered to be between the rear plate portion 72 and the front plate portion 73. The rear upper portion 82A and the front upper portion 83A of the holder heater 62 are sandwiched.

As a result, the heater unit 41 brings the lower ends of the rear plate portion 72 and the front plate portion 73 of the heater support member 61 into contact with the upper ends of the rear lower portion 82B and the front lower portion 83B of the holder heater 62, respectively. At this time, the heater unit 41 is restricted from being displaced in the front-rear direction of the holder heater 62 with respect to the heater support member 61. At this time, the heater unit 41 is in a state where the protrusions 82C and 83C are located on the left side of the left ends of the rear plate portion 72 and the front plate portion 73, and the protrusions 82D and 83D are inserted into the notches 72B and 73B. ..

Further, the heater unit 41 slides (that is, slides) the heater support member 61 to the left with respect to the holder heater 62. As a result, the protrusions 82C and 83C enter and engage with the notches 72A and 73A, respectively, and the upper right portions of the protrusions 82D and 83D enter and engage with the recesses 72D and 73D. As a result, in the heater unit 41, the displacement of the holder heater 62 in the vertical direction and the displacement in the right direction with respect to the heater support member 61 are both restricted.

Further, in the heater unit 41, a predetermined fixing screw is screwed into a screw hole (not shown) formed in the holder heater 62 through a hole (not shown) provided in the upper plate portion 71. , The position of the holder heater 62 with respect to the heater support member 61 is fixed. As a result, in the heater unit 41, the upper plate protruding portion 74 of the heater support member 61 protrudes to the left side of the left end of the holder heater 62.

Next, in the heater unit 41, the heater support member 61 and the holder heater 62 are turned upside down, and then the support plate 63 and the heater substrate 64 are placed on the holder heater 62. Specifically, in the heater unit 41, the support plate 63 is placed so as to be aligned with the substrate center portion 81A of the substrate portion 81 of the holder heater 62 that has been turned upside down, and the heater arrangement portion is further turned upside down. 91 is placed so as to be overlapped with the support plate 63.

At this time, the heater substrate 64 is inserted the positioning protrusion 95 into the engagement hole 82EH provided with the engagement portion 82E of the holder heater 62. As a result, the positions of the heater substrate 64 in the vertical direction and the horizontal direction with respect to the holder heater 62 are restricted. Incidentally, in the heater substrate 64, the electrode arranging portion 92 is in a state of protruding to the left side from the left end of the holder heater 62.

Next, in the heater unit 41, the heat diffusion member 65 is attached to the holder heater 62. Specifically, for example, the heat diffusion member 65 is inclined so that the vicinity of the left end is close to the vicinity of the left end of the holder heater 62, and the engaging portions 65BP and 65CP are engaged with the engaging projections 82F and 83F of the holder heater 62, respectively. Subsequently, the heat diffusion member 65 is subjected to an external force in a direction away from the holder heater 62 with respect to the vicinity of the center in the left-right direction, and in a bent state, the vicinity of the right end is brought closer to the vicinity of the right end of the holder heater 62, and eventually the rear plate portion 65B. And the front plate portion 65C is inserted into the rear groove portion 81B and the front groove portion 81C, respectively. Further, when the external force is released, the heat diffusion member 65 engages the engaging portions 65BQ and 65CQ with the engaging projections 82G and 83G of the holder heater 62, respectively.

As a result, the heater unit 41 is in a state where the heat diffusion member 65 is engaged with the holder heater 62, and the heat diffusion member 65 regulates the displacement of the support plate 63 and the heater substrate 64 with respect to the holder heater 62 in the vertical and front-rear directions. do. That is, the heater unit 41 is in a state in which the displacement of the heater substrate 64 with respect to the heater support member 61 in the vertical direction and the front-rear direction is restricted. Further, the heater unit 41 regulates the displacement of the heater substrate 64 with respect to the heater support member 61 in the left-right direction by the positioning projection 95 and the engaging portion 82E.

Next, in the heater unit 41, the holder connector 66 is attached to the heater support member 61. Specifically, in the heater unit 41, the heater support member 61 and the like are brought close to each other from the left side of the holder connector 66, and the upper plate protruding portion 74 of the heater support member 61 is inserted into the upper right hole portion 121 of the right side plate 103 of the holder connector 66. Then, it is further inserted into the support member through hole 122 of the upper center plate 107. Further, the heater unit 41 inserts the electrode arrangement portion 92 of the heater substrate 64 into the right heater substrate through hole 123 of the right plate 103 in the holder connector 66.

Eventually, in the heater unit 41, the hole 75 of the upper plate protrusion 74 and the protrusions 76 and 77 of the heater support member 61 are substantially directly below the mounting hole 131, the positioning hole 132 and the positioning notch 133 of the upper plate 102 of the holder connector 66. When it reaches, it is displaced upward with respect to the holder connector 66.

As a result, in the heater unit 41, the protrusions 76 and 77 of the upper plate protrusion 74 of the heater support member 61 are in a state of being inserted into the positioning hole 132 and the positioning notch 133 of the upper plate 102 of the holder connector 66, respectively. At this time, in the heater unit 41, the upper surface of the upper plate protruding portion 74 of the heater support member 61 abuts on the lower surface of the upper plate 102 of the holder connector 66, and the upper surface of the electrode arrangement portion 92 of the heater substrate 64 is the holder connector 66. It is in a state of being extremely close to or in contact with the lower surface of the partition plate 106.

In this state, in the heater unit 41, the fixing screw 69 is inserted into the mounting hole 131 of the upper plate 102 of the holder connector 66 from above, and is further rotated to cause the hole 75 of the upper plate protruding portion 74 of the heater support member 61. Is screwed into. As a result, as shown in FIG. 11, the heater unit 41 is in a state where the holder connector 66 is fixed to the heater support member 61. Along with this, in the heater unit 41, the positions of the electrodes 96 (FIG. 10) of the electrode arranging portions 92 on the heater substrate 64 are substantially fixed with respect to the lower space 113 of the holder connector 66. For convenience of explanation, in the following, the integrated heater support member 61, holder heater 62, and holder connector 66 are collectively referred to as a holding body 70.

After that, the heater unit 41 is incorporated into the heat generating roller portion 22 (FIGS. 5 and 6) according to the above-mentioned assembly procedure. Further, the heat generating roller portion 22 is incorporated in the fixing portion 18 (FIGS. 3 and 4). As a result, the heater unit 41 is in a state where the holder connector 66 is exposed from the left side surface of the housing 21 in the fixing portion 18 to the left side.

In this state, the heater unit 41 has the connectors 37 and 38 inserted into the holder connector 66, respectively. Specifically, in the heater unit 41, the connector 37 is brought closer to the front from the rear side of the holder connector 66, and eventually the terminal holding portion 162 is inserted into the lower space 113 and the holding portion 163 is inserted into the middle space 112. For convenience of explanation, the middle space 112 and the lower space 113 are also referred to as connector insertion points below.

At this time, the terminals 165 and 166 of the terminal holding portions 162 (FIG. 7) of the connector 37 are appropriately elastically deformed, and the electrodes 96A and 96B provided on the lower surface of the electrode arranging portion 92 of the heater substrate 64 (FIG. 10A). ), It is electrically connected to the electrodes 96A and 96B, respectively.

At this time, the lock lever 169 of the terminal holding portion 162 is pushed up slightly upward by the upper surface of the engaging portion 152 in the lower plate 104 of the holder connector 66, and further pushed upward by the inclined surface of the engaging claw 170. Eventually, when the engaging claw 170 reaches directly above the engaging hole 153 in the engaging portion 152, the lock lever 169 is displaced downward by the action of elastic force to move the engaging claw 170 into the engaging hole 153. Let it get in.

As a result, the connector 37 is in a locked state in which the engaging claw 170 of the lock lever 169 is engaged with the engaging hole 153 of the engaging portion 152 of the holder connector 66. At this time, the bottom surface of the notch 160, that is, the front inner side surface of the connector 37 is in contact with or extremely close to the front end portion of the lower partition plate 106 of the holder connector 66.

In this locked state, the connector 37 can hardly be displaced with respect to the holder connector 66 in any of the left-right direction, the up-down direction, and the front-back direction, and is in a substantially fixed state. That is, in the heater unit 41, when the connector 37 is inserted into the holder connector 66 and locked, the electrodes 96A and 96B of the electrode arrangement portion 92 on the heater substrate 64 are brought into contact with the terminals 165 and 166 of the connector 37, respectively, and are electrically connected. Can be maintained connected to.

Similarly, the connector 38 (FIGS. 3 and 7) is inserted into the front side of the holder connector 66 so that the terminals 165 and 166 are connected to the electrodes 96C and 96D of the electrode arrangement portion 92 on the heater substrate 64 (FIG. 10 (A). )) Can be brought into contact with each other and electrically connected.

[4. Effect, etc.]
In the above configuration, the fixing portion 18 of the image forming apparatus 1 according to the present embodiment has a longer front-rear length than the heater arranging portion 91 only at the left end of the heater substrate 64 (FIG. 10A) incorporated in the heater unit 41. An electrode arrangement portion 92 was provided, and two electrodes 96 were arranged at the front end and the rear end of the electrode arrangement portion 92, respectively.

Here, for comparison with the heater unit 41, a virtual heater unit 241 as shown in FIG. 12 is assumed. The heater unit 241 is significantly different from the heater unit 41 in that the connector 37 is connected to the right end, and the shape and the like of each component are also different accordingly. Specifically, the heater unit 241 has a heater support member 61, a holder heater 62, a heater support member 261 instead of the heater substrate 64, a holder heater 262, and a heater substrate 264. Further, the heater unit 241 has two holder connectors 266 and 267 instead of the holder connector 66.

Of these, the heater support member 261 and the holder heater 262 are configured so that the holder connector 266 can be attached to the left end and the holder connector 267 can be attached to the right end. The holder connector 267 has a configuration in which the front half of the holder connector 66 (FIG. 7) is removed. The holder connector 266 is configured substantially symmetrically with the holder connector 267. Connectors 38 and 37 are connected to the holder connectors 266 and 267, respectively. The connectors 37 and 38 are connected to the relay connector 35 via a cable 236 instead of the cable 36.

As shown in FIG. 10 (B) corresponding to FIG. 10 (A), the heater substrate 264 has a terminal arrangement portion 292 and a terminal arrangement portion 292 on the left and right sides of the heater arrangement portion 291 in which the heater 94 similar to the heater substrate 64 is arranged. Each terminal arrangement portion 293 is provided. Two electrodes 96 are arranged at the front ends of the terminal arrangement portion 292 and the terminal arrangement portion 293, respectively. When the connectors 38 and 37 are inserted into the holder connectors 266 and 267, the electrodes 96 of the terminal arrangement portion 292 and the terminal arrangement portion 293 have the terminals 165 and the terminals 165 of the connectors 38 and 37 inside the holder connectors 266 and 267, respectively. Each contacts with 166 (FIG. 7) and is electrically connected.

In the heater unit 241, when each heater 94 of the heater substrate 264 is heated, the heater substrate 264 expands as the temperature rises. The heater arranging portion 291 of the heater substrate 264 has the same size as the heater arranging portion 91 of the heater substrate 64, and the length in the left-right direction is sufficiently larger than the length in the front-rear direction.

Therefore, when the temperature rises, the heater arranging portion 291 expands at the same expansion rate in both the front-rear direction and the left-right direction, but the expansion amount in the front-rear direction is small, whereas the expansion amount in the left-right direction ( That is, the extension distance) becomes relatively large. As a result, in the heater substrate 264, the distance (that is, the distance) between the electrode 96 provided on the terminal arrangement portion 292 on the left side and the electrode 96 provided on the right side and the terminal arrangement portion 293 increases with increasing temperature. It will be expanded.

At this time, in the heater unit 241, the heater support member 261 and the holder heater 262 expand (extend) in the left-right direction due to the heat transferred from the heater substrate 264, but the temperature rise is small due to the heat transfer loss and the like. Since the materials are also different, the expansion rate is lower and the expansion amount is smaller than that of the heater substrate 264.

That is, in the heater unit 241 when the temperature rises due to the heating of the heater 94, the heater substrate 264 expands greatly in the left-right direction and extends the distance between the left and right electrodes 96, but is inserted into the holder connectors 266 and 267, respectively. The distance between the connectors 38 and 37 is only slightly extended. Therefore, in the heater unit 241, as the temperature rises, the electrode 96 of the heater substrate 264 slides largely to the left or right with respect to the terminals 165 and 166 of the connectors 38 and 37.

Further, in the heater unit 241, for example, when the heat generation of the heater 94 is stopped with the end of the printing process, the temperature of each part drops. At this time, in the heater unit 241 the electrode 96 of the heater substrate 264 slides largely in the direction opposite to the temperature rise with respect to the terminals 165 and 166 of the connectors 38 and 37.

In this way, in the heater unit 241, as the temperature rises and falls repeatedly, the electrodes 96 of the heater substrate 264 and the terminals 165 and 166 of the connectors 38 and 37 repeatedly slide, so that the contact portion is worn. , There is a risk of causing poor contact, that is, there is a risk that the heater 94 cannot generate heat.

On the other hand, in the heater unit 41 (FIG. 7 and the like) according to the present embodiment, the electrode arrangement portion 92 is provided only on the left side of the heater substrate 64, which is one of the main scanning directions (that is, the left-right direction) with respect to the heater arrangement portion 91. Two electrodes 96 were arranged at the front end and the rear end of the electrode arrangement portion 92 (FIG. 10 (A)). Further, in the heater unit 41, a positioning projection 95 is provided on the left side of the heater arrangement portion 91 on the left side of the left end of the heater 94 and relatively close to the electrode arrangement portion 92, and the positioning projection 95 is provided on the engaging portion 82E of the holder heater 62. By engaging, the position of the heater substrate 64 with respect to the holder heater 62 in the left-right direction was restricted (FIGS. 7 and 11).

As a result, in the heater unit 41, although the heater arrangement portion 91 of the heater substrate 64 expands (extends) significantly in the left-right direction due to the heat generated by the heater 94, the positioning provided near the connection portion between the heater arrangement portion 91 and the electrode arrangement portion 92. At the protrusion 95, the heater substrate 64 is not displaced in the left-right direction. Further, since the electrode arranging portion 92 is provided in the immediate vicinity of the positioning projection 95 in the left-right direction and the total length is much shorter than that of the heater arranging portion 91, the amount of expansion (extension amount) due to an increase in temperature is large. It can be regarded as extremely small and substantially non-displaceable.

Therefore, in the heater unit 41, the electrodes 96 of the heater substrate 64 and the terminals 165 and 166 of the connectors 37 and 38 hardly slide and may wear regardless of whether the temperature rises or falls. Since there is almost no contact, the risk of causing poor contact is extremely low. As a result, the heater unit 41 can stably maintain a state in which a current can be reliably supplied to the heater substrate 64 even when the temperature rises and falls repeatedly.

Further, in the virtual heater unit 241 (FIG. 12), since the connectors 38 and 37 are inserted into the holder connectors 266 and 267 at a position greatly separated in the left-right direction, the cable connecting the relay connector 35 and the connectors 38 and 37 is connected. It will be necessary to make 236 relatively long.

On the other hand, in the heater unit 41 (FIG. 3) according to the present embodiment, the connectors 37 and 38 are inserted into the holder connector 66 very close to each other so as to face each other in the front-rear direction. The cable 36 connecting to 38 can be made extremely short (FIG. 3). As a result, in the fixing portion 18 (FIG. 3), the length of the cable 36 required at the time of manufacturing can be suppressed to reduce the material cost, and the cable 36 is relatively short, as compared with the virtual heater unit 241. Therefore, it can be easily handled by workers and the like, so that it can be easily manufactured with a smaller number of work man-hours.

Further, in the heater unit 41 according to the present embodiment, in the electrode arrangement portion 92 of the heater substrate 64, the four electrodes 96 are not arranged in a row along the left-right direction, but are divided into two positions, a front end and a rear end. Two pieces were arranged (FIG. 10 (A)). As a result, the heater unit 41 can suppress the length of the electrode arrangement portion 92 in the left-right direction to about half as compared with the case where the four electrodes 96 are arranged in a row along the left-right direction. Along with this, in the fixing portion 18 (FIG. 3), the portion of the heater unit 41 projecting to the left side of the housing 21, that is, the total length in the left-right direction including the holder connector 66 can be suppressed to be extremely short.

From another point of view, in the heater unit 41, the connectors 37 and 38 are inserted and attached to the holder connector 66 from opposite directions in the front-rear direction (FIG. 3 and the like). As a result, in the heater unit 41, even if gravity, tension, or the like acts on the cable 36 connected to the connectors 37 and 38 and the relay connector 35 connected to the end thereof, a downward force acts on the front side. And since it can be dispersed to the rear side, it is possible to suppress the action of the force in the twisting direction on the upper plate protruding portion 74 of the heater support member 61 and the electrode arrangement portion 92 of the heater substrate 64.

By the way, for example, in another heater unit in which the heater is not divided in the main scanning direction, two cables may be connected, and therefore one connector having the same configuration as that of the connector 37 may be used. On the other hand, in the heater unit 41 according to the present embodiment, it is necessary to connect four cables in order to switch the heat generation pattern in three ways, but instead of connecting the four cables with one connector, Two connectors 37 and 38 to which two cables 36 are connected are used. As a result, in the heater unit 41, the connector 37 and the like can be shared with other heater units in which the heater is not divided in the main scanning direction.

From another point of view, the heater substrate 64 has the minimum length required for arranging the heater 94 and the predetermined wiring pattern in the heater arranging portion 91 in the front-rear direction, and the electrode arranging portions 92 are the connectors 37 and 38. The shape is longer than that of the heater arrangement portion 91, which is necessary for the connection (FIG. 10 (A)).

As a result, in the heater unit 41, the front-rear length of the portion to be accommodated inside the fixing belt 43 (FIG. 4, etc.), that is, the portion corresponding to the heater arrangement portion 91 is minimized, and the radius of the fixing belt 43 is also minimized. It can be suppressed to, and can contribute to miniaturization. On the other hand, in the heater unit 41, in the portion corresponding to the electrode arrangement portion 92, the two connectors 37 and 38 are arranged so as to face each other in the front-rear direction, and the two connectors interfere with each other while suppressing the length in the left-right direction. It is possible to secure the required length in the front-rear direction without causing it.

Incidentally, in the heater unit 41, the cable 36 is not directly connected to the electrode 96 of the heater substrate 64 by soldering or the like, but is connected via the connectors 37 and 38. As a result, in the fixing portion 18 to which the heater unit 41 is attached, the assembly work can be facilitated as compared with the case where soldering or the like is performed, and when the heater unit 41 is replaced due to a failure or deterioration after assembly. Even if there is, the replacement work can be extremely facilitated.

According to the above configuration, the fixing portion 18 of the image forming apparatus 1 is provided with the electrode arranging portion 92 on only one of the main scanning directions with respect to the heater arranging portion 91 in the heater substrate 64 incorporated in the heater unit 41, and the electrode arranging portion is provided. Two electrodes 96 were arranged at the front end and the rear end of the portion 92. Further, in the heater unit 41, the position of the heater substrate 64 with respect to the holder heater 62 in the left-right direction is provided by the positioning projection 95 provided on the left side of the heater arrangement portion 91 on the left side of the left end of the heater 94 and relatively close to the electrode arrangement portion 92. Was regulated. As a result, in the heater unit 41, when the temperature rises or falls, the electrodes 96 of the heater substrate 64 and the terminals 165 and 166 of the connectors 37 and 38 hardly slide and may wear. Since there is almost no contact failure, a stable electrical connection can be maintained.

[5. Other embodiments]
In the above-described embodiment, the case where the positioning projection 95 is provided on the rear side between the heat generation range 91A and the electrode arrangement portion 92 in the heater substrate 64 (FIG. 10A) has been described. However, the present invention is not limited to this, and for example, a positioning projection 95 may be provided on the front side between the heat generation range 91A and the electrode arrangement portion 92 in the heater substrate 64, or the positioning projection 95 may be provided on the electrode arrangement portion 92. The holder connector 66 may be provided with the engaging portion 82E or a shape corresponding thereto. In short, one or two or more positioning protrusions 95 may be provided on the heater substrate 64 on the left side of the left end of the heater 94.

Further, in the above-described embodiment, a positioning protrusion 95 having a shape protruding rearward from the surroundings is provided on the rear side of the heat generation range 91A in the heater substrate 64 (FIG. 7), and the holder heater 62 is provided with an engagement hole 82EH. The engaging portion 82E having the above is provided. Then, in the embodiment, the case where the position of the heater substrate 64 with respect to the holder heater 62 in the left-right direction is determined by inserting the positioning protrusion 95 into the engagement hole 82EH has been described. However, the present invention is not limited to this, and various well-known shapes and structures may be used, for example, a notch is formed in the heater substrate 64 and a protrusion is formed in the holder heater 62 to engage the two. In short, it suffices if the position of the heater substrate 64 with respect to the holder heater 62 in the left-right direction can be regulated.

Further, in the above-described embodiment, the case where the heater 94 divided into five is arranged in the heat generation range 91A of the heater substrate 64 (FIG. 10A) has been described. However, the present invention is not limited to this, and for example, one heater 94 may be arranged in the heat generation range 91A, or two or more heaters 94 divided into arbitrary numbers may be arranged.

Further, in the above-described embodiment, the case where the electrode arrangement portion 92 is configured to be longer than the heater arrangement portion 91 with respect to the length in the front-rear direction in the heater substrate 64 (FIG. 10A) has been described. However, the present invention is not limited to this, and for example, the heater arrangement portion 91 and the electrode arrangement portion 92 may be equivalent with respect to the length in the front-rear direction of the heater substrate 64. In this case, the front-rear lengths of the connectors 37 and 38 may be shortened, that is, the terminals 165 and the like can be brought into contact with the electrodes 96 without interfering with the connectors 37 and 38.

Further, in the above-described embodiment, the case where the terminals 165 and the like are brought into contact with each of the four electrodes 96 by the two connectors 37 and 38 has been described (FIG. 10 (A)). However, the present invention is not limited to this, and terminals 165 and the like may be brought into contact with each electrode 96 by, for example, one or three or more connectors. Further, when a plurality of connectors 37 and the like are used, the connectors may have the same shape or different shapes from each other.

Further, in the above-described embodiment, the case where the holding body 70 of the heater unit 41 (FIGS. 7 and 11), that is, the heater support member 61, the holder heater 62, and the holder connector 66 are configured as independent parts is described. However, the present invention is not limited to this, and for example, the holding body 70 may be configured as an integral component, or may be configured by a plurality of components divided at arbitrary points. In short, it is sufficient that it has sufficient strength (rigidity), can hold the heater substrate 64, and can hold the terminals 165 and the like in contact with each electrode 96 by inserting the connectors 37 and 38.

Further, in the above-described embodiment, in the fixing portion 18 (FIGS. 3 and 4), the lower surface of the heater unit 41, that is, the surface of the heater substrate 64 on which the heater 94 is arranged faces downward, and the fixing belt 43 is sandwiched. The case of facing the backup roller 23 has been described. However, the present invention is not limited to this, and heat may be transferred to the fixing belt 43 by directing the heater in a direction other than the backup roller 23, for example, as shown in FIG. 2 in Patent Document 1.

Further, in the above-described embodiment, in the fixing portion 18 (FIGS. 3 and 4), the state switching portion 30 (that is, the heat generating roller portion rotating shaft 24, the cam 26 spring 28, the cam urging portion 53, the spring receiving portion 54, etc.) ), The case where the heat generating roller portion 22 is switched to the nip state or the non-nip state has been described. However, the present invention is not limited to this, and for example, each component of the fixing portion 18 may be omitted or simplified so that the heat generating roller portion 22 is fixed in the nip state.

Further, in the above-described embodiment, the control unit 3 (FIG. 1) recognizes the approximate length of the paper P in the main scanning direction based on the detection result of the sensor 6, and the heater substrate 64 (FIG. 10) is based on this. The heat generation pattern in (A)), that is, the case of switching which heater 94 is to generate heat has been described. However, the present invention is not limited to this, and the heat generation pattern is recognized by recognizing the approximate size of the paper P in the main scanning direction based on various other information such as the paper size notified from a higher-level device such as a computer device. You may switch between. Alternatively, for example, when an image is formed only on a part of the paper P, the control unit 3 may analyze the image data and then control to heat only the heater at the portion corresponding to the position of the image. ..

Further, in the above-described embodiment, the case where the present invention is applied to the image forming apparatus 1 which is a single-function printer (that is, SFP) has been described. However, the present invention is not limited to this, for example, a multifunction device having an image scanner function, a communication function, etc. in addition to a printer function and capable of operating as a copying machine (copier) or a facsimile machine, that is, a so-called MFP (Multi Function Peripheral). / Printer) may be applied. Further, the present invention may be applied to various devices having an electrophotographic printing function, such as a facsimile machine and a copying machine.

Further, in the above-described embodiment, the case where the present invention is applied to the heater unit 41 incorporated in the fixing portion 18 of the image forming apparatus 1 has been described. However, the present invention is not limited to this, and the present invention may be applied to a heater unit mounted on various other devices.

Furthermore, the present invention is not limited to the above-described embodiments and other embodiments. That is, the present invention has an applicable scope to an embodiment in which each of the above-described embodiments and a part or all of the above-mentioned other embodiments are arbitrarily combined, and an embodiment in which a part is extracted. Is.

Further, in the above-described embodiment, the case where the heater unit 41 as the heater unit is configured by the heater substrate 64 as the substrate and the holding body 70 as the holding body has been described. However, the present invention is not limited to this, and the heater unit may be configured by a substrate having various other configurations and a holding body.

The present invention can be used, for example, in a fixing portion of an image forming apparatus having an electrophotographic printing function.

1 ... image forming device, 3 ... control unit, 11 ... image forming unit, 18 ... fixing unit, 21 ... housing, 22 ... heating roller unit, 23 ... backup roller, 24 ... heating roller Part rotation shaft, 25 ... camshaft, 26 ... cam, 28 ... spring, 30 ... state switching part, 37, 38 ... connector, 41 ... heater unit, 43 ... fixing belt, 61 ... Heater support member, 62 ... holder heater, 63 ... support plate, 64 ... heater board, 65 ... heat diffusion member, 66 ... holder connector, 69 ... fixing screw, 70 ... holder, 82E ... Joint part, 82EH ... Engagement hole, 91 ... Heater arrangement part, 91A ... Heat generation range, 92 ... Electrode arrangement part, 94 ... Heater, 95 ... Positioning protrusion, 96 ... Electrode, 161 ... Base , 162 ... Terminal holding part, 163 ... Holding part, 165 ... Terminal.

Claims (9)

A heater is provided in a heat generation range along the main scanning direction, and an electrode electrically connected to the heater is provided at a position distant from the heat generation range in one direction with respect to the main scanning direction. A substrate provided with a positioning unit that determines the position in the main scanning direction on one direction, and
When the position of the substrate is determined by the positioning portion with respect to the main scanning direction and a connector having a terminal to which a current is supplied is inserted at a predetermined connector insertion point, the terminal of the connector abuts on the electrode of the substrate. Equipped with a holder that holds it in a state where it is left in place ,
In the electrode arrangement portion provided with the electrodes, the electrodes are arranged side by side in the sub-scanning direction intersecting the main scanning direction on the surface of the substrate.
The retainer is provided with the connector insertion points on both sides in the sub-scanning direction.
The connectors inserted into the connector insertion points face each other in the sub-scanning direction.
A heater unit characterized by that. The heater unit according to claim 1, wherein the substrate has the positioning portion arranged between the heat generation range and the portion where the electrode is provided. In the substrate, the heater is divided into two or more heat generation regions, and the electrodes are provided in the same number as or more than the number of heat generation regions.
The heater unit according to claim 1, wherein the connector has a number of the terminals equal to or larger than the number of heat generation regions. The heater unit according to claim 1 , wherein the holding body has the connectors having the same shape as each other inserted into the connector insertion portions provided on both sides in the sub-scanning direction. The heater unit according to claim 1 , wherein the substrate is formed so that the electrode arrangement portion is formed longer than the heater arrangement portion provided with the heater in the sub-scanning direction. A heating roller unit having the heater unit according to any one of claims 1 to 5 , and a fixing belt that circulates around the heater unit.
A backup roller that has a cylindrical shape along the main scanning direction and is arranged so that the peripheral side surface is in close proximity to or in contact with the fixing belt of the heat generating roller portion.
A fixing device characterized in that the backup roller is rotatably supported and a housing that supports the heat generating roller portion is provided. 6. The housing according to claim 6 , further comprising a state switching portion for switching the heat generating roller portion between a nip state in which the heat generating roller portion is pressed against the backup roller and a non-nip state in which the heat generating roller portion is separated from the backup roller. Fixing device. An image forming unit that forms a developer image using a developer and transfers the developer image to a predetermined medium.
The image forming apparatus according to any one of claims 6 or 7 , further comprising a fixing device for fixing the developer image transferred to the medium to the medium. A transport unit that transports any of the plurality of types of media having different lengths in the main scanning direction, and
A sensor that detects the length of the medium conveyed by the conveying unit in the main scanning direction, and
In addition to acquiring the detection result by the sensor, the transport unit, the image forming unit, and the control unit that controls the fixing device are further provided.
In the substrate of the heater unit, the heater is divided into two or more heat generation regions with respect to the main scanning direction and arranged.
Based on the detection result obtained by the sensor, the control unit controls which of the two or more heat generation regions in the heater unit generates heat according to the length of the medium with respect to the main scanning direction. The image forming apparatus according to claim 8 .

Images