Patent Grant
8995868
The present invention relates to a fixing apparatus (device) for an image forming apparatus, and a connector for supplying the fixing apparatus (device) with electric power.
An apparatus having a combination of an endless belt and a ceramic heater which is in contact with the inward surface of the endless belt has been put to practical use as a fixing apparatus for thermally fixing a toner image formed on a sheet of recording medium, to the sheet of recording medium. A ceramic heater used by such an apparatus has a ceramic substrate, a heat generating member, and electrodes which are in electrical connection with the heat generating member. The heater is held by a heater holder made of resin. It is to the electrode(s) of the heater that a connector for supplying the heater with electric power is connected.
The connector is provided with a terminal (or terminals), which is within the connector. In order to ensure that the terminal of the power supply connector remain satisfactorily connected with the electrodes of the heater, it is necessary for a preset amount of contact pressure to be maintained between the terminal of the power supply connector and the heater electrodes.
The connector disclosed in Japanese Patent No. 4585668 has a terminal having a pair of spring contacts which sandwich a heater as the connector is engaged with the electrodes of the heater. One of the spring contacts plays the role of an electrical contact which contacts the electrode of the heater, whereas the other (support spring) plays the role of keeping the heater pressed toward the heater holder, with the presence of a spacer between itself and the heater.
The connector is structured so that the contact pressure between the spring support and the heater (spacer) becomes greater than the contact pressure between the spring contact (as electrical contact) and the electrode. Thus, it does not occur that the heater separates from the heater supporting surface of the heater holder. Therefore, the connector disclosed in the abovementioned Japanese Patent is higher in the level of accuracy, than a conventional connector, in terms of the positional relationship between the electrodes of the heater and the terminal of the connector, which in turn can keep the spring contacts of the connector stable in the amount by which the points of contact of the spring contacts are displaced, or the angle by which they are bent. With the spring contacts being kept stable in the amount by which the points of contact are displaced, or the angle by which the spring contacts are bent, the contact pressure between the spring contacts of the connector, and the electrodes, one for one, of the heater, remain stable at a preset, desired, level. Thus, this connector is suitable as a connector for a fixing device, the heater of which is attached to the heater holding surface of the heater holder so that the heat generating member of the heater faces the heater holding surface.
However, in a case where the connector disclosed in Japanese Patent No. 4585668 is used as the connector for a heater having a heater or heaters, on both of the primary surfaces of its ceramic substrate (this heater will be referred to as “two-sided heater”, hereafter), it is possible that the contact pressure between one of the spring contacts of the connector terminal and the electrode of the heater on the top surface, for example, of the two-sided heater will become different from the contact pressure between the other spring contact of the connector terminal and the corresponding electrode of the heater. If the contact pressure between one of the spring contacts of the connector terminal and the electrode of the heater on the top surface of the two-sided heater is substantially different from the contact pressure between the other spring contact of the connector terminal and the corresponding electrode, the two-sided heater is subjected to a substantial amount of stress. Thus, in order to prevent the ceramic substrate of the two-sided heater from being broken by the stress, the connector is designed so that it is as small as possible in the amount of the stress which it imparts to the ceramic substrate of the heater.
Therefore, the two sides of a two-sided heater have to be made the same in the amount of contact pressure between the electrode of the heater and the spring contact of the terminal of the connector for the heater. Further, a connector for a two-sided heater is structured so that when it is engaged with a two-sided heater, its two spring contacts come into contact with the electrodes of the heater in such a manner that they oppose each other with the presence of the electrode of the two-sided heater between them. Thus, the amount of displacement of the point of contact of each spring contact when the connector is engaged with the two-sided heater is affected by the thickness of the substrate of the heater. For example, if the substrate of the two-sided heater is reduced in thickness, the amount of displacement of the point of contact of the spring contact of the connector also decreases.
Further, if a two-sided heater, the substrate of which is very thin, deviates in position because of the tolerance for heater components, and/or the components related to the heater, the point of contact of the spring contact of the connector sometimes separates from the heater, resulting in unsatisfactory fixation attributable to the interruption of the electric power supply to the heater. In order to prevent the occurrence of this problem, the components related to a heater (two-sided heater in particular) are required to have a high level of accuracy in measurement, which possibly reduces the yield of the mass-production of the aforementioned components.
Thus, the primary object of the present invention, which was made in consideration of the above described issue, is to provide a connector which can engage with the electrode of a heater in such a manner that as the connector is engaged with the electrode of the heater, a preset (proper) amount of contact pressure is generated and maintained between the electrode of a heater and the spring contact of the connector, and also, to provide a fixing apparatus (device) which has such a connector.
According to an aspect of the present invention, there is provided an image fixing apparatus for heating and fixing an unfixed image formed on a recording material, comprising: a heater including a substrate, a first electrode provided on one side of said substrate and a second electrode provided on the other side of the substrate; and a connector, connected with the heater, for receiving electric power, the connector including an electrically insulative housing, and a contact terminal provided inside the housing and having first spring contact contacted to the first electrode and a second spring contact contacted to the second electrode, wherein the contact terminal is swingable relative to the housing.
According to another aspect of the present invention, there is provided an electrical connector for electric power supply, the connector comprising: an electrically insulative housing; and a contact terminal provided inside the housing and including a first spring contact for contacting to a first electrode provided on one side of a heater substrate and a second spring contact for contacting to a second electrode provided on the other side of the substrate. The contact terminal is swingable relative to the housing.
According to a further aspect of the present invention, there is provided an image fixing apparatus for heating and fixing an unfixed image formed on a recording material, comprising: a heater including a substrate, and an electrode provided on the substrate; a connector, connected with the heater, for receiving electric power, the connector including an electrically insulative housing, and a contact terminal provided inside the housing and having spring contact contacted to the electrode, a holder holding the heater. The contact terminal is provided, at a position opposing the spring contact, with a projection cooperating with the spring contact to nip the holder, and the contact terminal is swingable with a fulcrum at the projection.
According to a further aspect of the present invention, there is provided an electrical connector for electric power supply, the connector comprising an electrically insulative housing; and a contact terminal provided inside the housing and including a spring contact for contacting to an electrode provided on heater. The contact terminal is provided, at a position opposing the spring contact, with a projection cooperating with the spring contact to nip a holder for holding the heater, and the contact terminal is swingable with a fulcrum at the projection.
According to a further aspect of the present invention, there is provided an image fixing apparatus for heating and fixing an unfixed image formed on a recording material, comprising: a heater including a substrate, and an electrode provided on the substrate; a connector, connected with the heater, for receiving electric power, the connector including an electrically insulative housing, and a contact terminal provided inside the housing and having spring contact contacted to the electrode. A hook shaped portion is provided by two surfaces perpendicular to each other, between the fulcrum of swing and a contact portion of the spring contact contacting to the electrode.
According to a further aspect of the present invention, there is provided an electrical connector for electric power supply, the connector comprising: electrically insulative housing; and a contact terminal provided inside the housing and including a spring contact for contacting to an electrode of a heater. A hook shaped portion is provided by two surfaces perpendicular to each other, between the fulcrum of swing and a contact portion of the spring contact contacting to the electrode.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
a), 2(b), and 2(c) are perspective views of the heater and heater supporting member, and shows how the heater is supported by the heater supporting member.
a)-3(c) are drawings for showing the structure of the heater.
a)-10(d) are schematic drawings of the connector in the second embodiment of the present invention, and shows the structure of the connector.
a)-11(c) are drawings of the combination of the connector (shown in
a)-13(c) are drawings drawing of the combination of the heater and the heater supporting member in the third embodiment of the present invention, and show the structure of the combination.
a) and 14(b) are sectional views of the combination of the connector, the heater, and the heater supporting member in the third embodiment the present invention, when the connector is in engagement with the heater and the heater supporting member.
a)-(c) are a combination of drawings of the heater and the heater supporting member, which show the overall structure of the heater and the heater supporting member.
First, a connector in accordance with the present invention, and a fixing apparatus (device) having this connector, in this embodiment, are concretely described.
<Image Forming Apparatus>
This embodiment is described with reference to an electrophotographic color image forming apparatus having four photosensitive drums.
Referring to
The cartridges 25y, 25m, 25c and 25k are provided with photosensitive drums 26y, 26m, 26c and 26k (as the image bearing member, collectively and individually referred to as the photosensitive drum 26), and charging apparatuses (devices) 27y, 27m, 27c and 27k, respectively, for uniformly and negatively charging the photosensitive drums 26y, 26m, 26c and 26k. They are also provided with development rollers 28y, 28m, 28c and 28k, respectively, for adhering toner to an electrostatic latent image to develop the latent image into a toner image, that is, a visible image formed of toner. They are also provided with cleaning blades 29y, 29m, 29c and 29k, respectively, for removing the toner remaining on the peripheral surface of the photosensitive drums 26y, 26m, 26c and 26k.
The printer 22 is also provided with a scanner 30 (scanning unit) and an intermediary transfer unit 31, which are in the adjacencies of the four cartridges. The scanner 30 forms an electrostatic latent image on the peripheral surface of each photosensitive drum 26 by projecting a beam of laser light upon the peripheral surface of the photosensitive drum 26, while modulating the beam according to the information of the image to be formed.
The intermediary transfer unit 31 has four primary transfer rollers 32y, 32m, 32c and 32k, an intermediary transfer belt 33, a driver roller 34, and an idler roller 35. It forms a unit by being combined with a cleaning device 36 for removing the transfer residual toner remaining on the intermediary transfer belt 33. The intermediary transfer belt 33 is an endless (cylindrical) belt, and is suspended by the driver roller 34 and idler roller 35. The idler roller 35 is grounded. It is kept pressured by an unshown pressure applying means in the direction indicated by an arrow mark d in
As the driver roller 34 is rotationally driven by an unshown motor or the like, the intermediary transfer belt 33 is circularly moved in the direction indicated by an arrow mark e in
After the transfer (primary transfer) of the toner images from the photosensitive drums 26 onto the intermediary transfer belt 33, in the nips formed between the primary transfer roller 32 and photosensitive drums 26, the toner images on the intermediary transfer belt 33 are transferred onto a sheet of a recording medium, in the secondary transfer station 37. Then, the sheet of the recording medium, on which the toner images have just been borne, is processed by the fixing device 1, and the toner images are fixed to the sheet of the recording medium. Designated by a reference numeral 38 is a flapper for switching the direction in which a sheet of the recording medium is to be conveyed after the fixation of the toner images on the sheet of the recording medium. More specifically, the flapper 38 guides the sheet of the recording medium toward a pair of discharge rollers 39, or to a switchback roller 40. As the sheet S of the recording medium is guided toward the switchback roller 40, it is conveyed backward by the switchback roller 40, being thereby conveyed through the secondary transfer station 37 and the fixing device 1, and then, is guided toward the discharge rollers 39. Then, it is discharged into a delivery tray 41 by the discharge rollers 39 (through nip between two rollers 39).
<Fixing Apparatus (Device)>
Next, referring to
The heating unit 2 has a cylindrical film 7 (endless belt), a heater 5, and a heater supporting member 6 (heater holder) which supports the heater 5. Referring to
The heat generating members 8a and 8b, which are on the front and rear surfaces, one for one, of the substrate 9, are different in dimension in terms of the lengthwise direction (left and right directions in
The layout of the electrodes 10a-10d is as follows.
The electrodes 10b and 10d provided on the front and rear surfaces, one for one, at the same lengthwise end portions (right end portion in
It is to the electrodes of the heater 5 that the connector for supplying the heater with electric power is connected. More specifically, it is to the electrodes 10b and 10d that the connector 13 having two spring contacts, which correspond to electrodes 10b and 10d, one for one, is connected.
The connector 13 is made up of a dielectric housing 15, and a terminal 14 (shown in
The heating unit 2 is kept pressed against the pressure roller 3 by an unshown pressure applying means, whereby the film 7 and the pressure roller 3 are kept pressed upon each other. The pressure roller 3 rotates by being driven by an unshown external mechanical power source. The film 7 is rotated by the rotation of the pressure roller 3.
A sheet S of a recording medium bearing an unfixed toner image formed in the unshown image formation station of the image forming apparatus is conveyed to, and then through, the fixation nip 20, which is the area of contact between the heating unit 2 and the pressure roller 3. As the sheet S is conveyed through the fixation nip 20, the toner in the unfixed toner image is fixed (permanently adhered) to the sheet S by the heat and pressure in the fixation nip 20. Thereafter, the sheet S, which is bearing the fixed toner image, is discharged into an unshown delivery area by a pair of sheet conveyance rollers 4.
<Heating Unit>
Next, referring to
First, referring to
The heater 5 has the dielectric substrate 9 made of ceramic material. It has also the heat generating members 8a and 8b, which are on the front and rear surfaces, respectively, of the substrate 9. Further, it has electrodes 10a-10d which the pair of spring contacts 16a and 16b of the connector terminal 14 contact, as shown in
The heat generating members 8a and 8b are made different in dimension in terms of the lengthwise direction (left and right directions in
Next, referring to
That is, the heat generating members 8a and 8b generate heat by the amounts proportional to the supplied amount of electric power. Thus, the amount of heat generated by the heater 5 can be controlled by deciding whether both or only one of the two heat generating members 8a and 8b is to be supplied with electric power.
<Attachment of Connector>
Next, referring to
The heater supporting member 6 is provided with a groove 6a which extends in the lengthwise direction (left and right directions in
Referring to
<Structure of Connector>
Next, referring to
Referring to
The connector terminal 14 is provided with the pair of spring contacts 16a and 16b, which press on the pair of electrodes on the front and rear surfaces, one for one, of the heater 5, so that a preset amount of contact pressure is generated, and maintained, between the spring contacts 16a and 16b and the corresponding electrodes of the heater 5. The two spring contacts 16a and 16b are the same in shape, and are symmetrically positioned with reference to a plane parallel to the front and rear surfaces of the housing 15 and coincides with the center of the housing 15 in terms of the direction perpendicular to the front and rear surfaces of the housing 15. Referring again to
The housing 15 of the connector 13 is structured so that there is a space 15b, which is U-shaped in cross section and allows the connector terminal 14 to perpendicularly (vertical direction in
The connector terminal 14 is fitted into the housing 15 by being inserted into the housing 15 from an unshown opening of the housing 15, which is on the opposite side (right side in
Referring to
The connector 13 and its terminal 14 are structured so that as the terminal 14 is inserted into the housing 15 of the connector 13, the spring contacts 16a and 16b oppose each other in the vertical direction in
As the connector 13 is connected to the heater 5, the housing 15 of the connector 13 sandwiches the heater supporting member 6, whereas the pair of spring contacts 16a and 16b of the connector terminal 14 come into contact with the electrodes 10d and 10b, respectively, of the heater 5, in the housing 15, so that the heat generating members 8a and 8b can be supplied with electric power.
That is, as the connector 13 engages with the heater supporting member 6 on which the heater 5 is held, the housing 15 engages with the heater supporting member 6. The spring contacts 16a and 16b come into contact with the electrodes 10d and 10b on the front and rear surfaces, one for one, of the heater 5, in such a manner that a preset amount of contact pressure is generated and maintained between the spring contacts 16a and 16b, and the electrodes 10d and 10c, respectively.
Next, referring to
In such a case, the position of the heater 5 relative to the housing 15 in terms of the vertical direction in
Therefore, the connector terminal 14 moves in the vertical direction in
Next, the connector in the second embodiment, and the connector in the third embodiment, are described. The only difference in the second and third embodiments from the first embodiment is in the shape of the connectors. Therefore, the second and third embodiments are described regarding the difference of their connectors from the connector 13 in the first embodiment. In the following description of the second and third embodiment, the heater, the heater holder, and the electrodes (on both surfaces of heater substrate, one for one), are referred to as heater 100, the heater holder 106, and the electrodes 103d and 103e.
a) is a side view of the terminal 120 of the connector 110, and shows the structure of the terminal 120.
Referring to
The pair of spring contacts 121 extend toward each other from the top and bottom sides of the slot 120X. That is, the first spring contact 121 (top spring contact in
The pair of protrusions 122 protrude toward each other from the top and bottom edges of each slot 120X of the connector terminal 120, so that each protrusion 122 coincides in position with the point 125 of contact of the corresponding spring contact 121. More specifically, the first protrusion 122 (bottom protrusion in
The connector terminal 120 is roughly U-shaped in cross section. It is made of stainless steel, titanium alloy, or the like substance, and is plated. It is provided with the pair of spring contacts 121, which are on the top and bottom sides, one for one, of the slot 120X. Each spring contact 121 has the point 125 of contact, which is the actual portion of the spring contact 121, by which the spring contact 121 presses upon one of the electrodes of the heater 100. The connector terminal 120 is provided with four protrusions 122 (which contact heater 100), which coincide with a vertical plane P (in
Further, the end portion of the connector terminal 120, which is on the opposite side of the connector terminal 120 from the slot 120X, is connected to a bundle 123 of fine wires, so that voltage can be applied to the connector terminal 120 through the bundle 123 of fine wires. As described above, the connector 110 is made up of the housing 111, and the connector terminal 120 fitted in the housing 111. The housing 111 is roughly U-shaped in cross section like the lateral walls of the connector terminal 120 of the connector 110. The housing 111 is provided with a pair of retainers 112, which prevent the connector terminal 120 from coming out of the housing 111 after the insertion of the terminal 120 into the housing 111 from the opposite side of the housing 111 from the opening 111X of the housing 111. Further, the connector 110 is structured so that after the proper insertion of the connector terminal 120 into the housing 111, there is a clearance A between the connector terminal 120 and housing 111.
a) is a sectional view of the combination of the connector 110 and heater 100 after the connection of the connector 110 to the heater 100.
As the connector 110 is engaged with the supporting member 106, which is supporting the heater 100, the supporting member 106 comes into contact with the vertical edge 124 (in
More specifically, as the connector 110 is engaged with the supporting member 106 on which the heater 100 is present, each protrusion 122 comes into contact with the supporting member 106 at the same time as the corresponding point 125 of contact of the spring contact 121 comes into contact with the electrode of the heater 100.
In this case, the first spring contact 121 presses on the first electrode 103e from the top side of the heater 100, and the first protrusion 122 comes into contact with the supporting member 106 from the bottom side of the supporting member 106. Further, the second spring contact 121 presses on the second electrode 103d from the bottom side of the second electrode 103d, and the second protrusion 122 comes into contact with the supporting member 106 from the top side of the supporting member 106. Consequently, the supporting member 106 is sandwiched by the first and section protrusions 122.
Therefore, there is virtually no change in the position of the point 125 of contact of the spring contact 121. Therefore, there occurs no change in the amount of the contact pressure between the point 125 of contact of the spring contact 121 and the corresponding electrode of the heater 100. Therefore, it does not occur that as the connector terminal 120 becomes tilted, the point 125 of contact of the spring contact 121 becomes separated from the electrode of the heater 100. Incidentally, even if the connector 110 is structured so that the protrusion 122 directly contacts the heater 100, instead of the supporting member 106, in the plane P which coincides with the point 125 of contact, the effect of the present invention is the same as the above described one.
a) is a perspective view of the combination of the heater 140 to which the connector 210 is attached, and the supporting member 106 for supporting the heater 140, in the third embodiment. It shows the structure of the combination.
The connector in the second embodiment is for a two-sided heater, that is, a heater having a heat generating member on both the top and bottom surface of its substrate. In comparison, the connector in this embodiment is for a one-sided heater 140, that is, a heater having a heat generating member 102 and an electrode 103 for the heat generating member 102, on only one of the top and bottom surfaces of its substrate. First, how the one-sided heater 140 is supported by the supporting member 106 is described with reference to
Referring to
a) is a sectional view of the combination of the connector 210 and the one-sided heater 140 after the engagement of the connector 210 with the heater 140.
The spring contact 121 extends diagonally downward from the top side of the slot 220X. To describe this structure in detail, the base portion of the spring contact 121 is a part of the top wall of the connector terminal 220, and extends diagonally downward into the space of the terminal 220, which corresponds in position to the slot 220X so that the point 125 of contact of the terminal 220 coincides in position with the slot 220X. Thus, as the connector 210 is attached to the heating unit, the point 125 of contact of the spring contact 121 comes into contact with the electrode 103 of the one-sided heater 140.
One of the protrusions 122 protrudes upward from the bottom edge of the slot 220X, toward the point 125 of contact of the spring contact 121. Thus, as the connector 210 is engaged with the heating unit, the protrusion 122 comes into contact with the spacer 132 attached to the supporting member 106, and the spring contact 121 comes into contact, from above, with the electrode 103 exposed through the hole 107, and presses on the electrode 103 so that a preset amount of contact pressure is generated and maintained between the point 125 of the spring contact 121 and the electrode 103.
Since the connector 210 and the heating unit in this embodiment are structured as described above, the contact pressure between the point 125 of contact (which opposes bottom protrusion 122) and the electrode 103 of the heater 140 does not decrease from the initial amount (preset amount), even if the connector 120 is subjected to an external force. Further, even if the terminal 220 is moved by an external force in the opposite direction, all that happens is that the connector terminal 120 pivotally moves about the adjacencies of the protrusion 122 in an oscillatory manner. Therefore, the contact pressure between the point 125 of contact and the electrode 103 does not change.
b) is a sectional view of one of the modified versions of the connector 210 in the third embodiment of the present invention. Referring to
To describe this structure in detail, the connector terminal 320 is provided with not only the protrusion 122, which protrudes upward from the bottom edge of the slot 320X, but also is provided with the protrusion 122, which protrudes downward from the top edge of the slot 320X. The connector terminal 320 is structured so that the two protrusions 122 squarely oppose each other. Further, the connector terminal 320 is provided with a spring contact 121 having a point 125 of contact. The point 125 of contact comes into contact with the electrode 103 of the one-sided heater 140 in such a manner that a preset amount of contact pressure is generated and maintained between itself and the electrode 103, as the connector 310 is engaged with the heater 140. The position of the point 125 of contact coincides with the plane P, which coincides in position with the top and bottom protrusions 122. Thus, as the connector 310 is engaged with the heater 140, the supporting member 106 by which the one-sided heater 140 is supported comes into contact with the bottom edge 124 of the slot 320X, and the point 125 of contact of the spring contact 121 comes into contact with the electrode 103, generating a preset amount of contact pressure between itself and the electrode 103. Further, the protrusions 122 come into contact with the supporting member 106.
Since the modified version 310 of the connector terminal 320 in the third embodiment is structured as described above, if the connector terminal 320 is subjected to an external force such as the reactive force which occurs as the bundle 123 of fine wires attached to the connector terminal 320 is moved, all that occurs is that the connector terminal 320 pivotally moves about the adjacencies of the protrusions 122, within the housing 111. Therefore, the contact pressure between the point 125 of contact (which coincides with plane P which coincide with the protrusion 122) and the electrode 103 does not change.
The combinations of connector, the heater, and the supporting member in the first and second embodiment, and the modified version of the combination in the third embodiment, are structured as described above. Therefore, even if the contact terminals are changed in attitude in the housing by an external force, a preset amount (proper amount) of contact pressure is maintained between the spring contact and heater electrode. That is, even if the attitude of the connector terminal is forced to change in the housing, by an external force, the terminal pivotally moves about the protrusion, within the housing in an oscillatory manner. Therefore, it is ensured that the preset amount (proper amount) of contact pressure is maintained between the spring contact and the heater electrode.
Next, the fourth and fifth embodiments of the present invention are described regarding the connector. The fourth and fifth embodiments are different from the preceding embodiments only in the shape of the connector. Therefore, their description will concentrate on the difference between the connectors in the fourth and fifth embodiments, and the connectors in the preceding embodiments.
The connector in this embodiment is suitable for supplying electric power to a heater having an electrode on only one of its primary surfaces.
The connector 313 has the regulating member 317, which is within the housing 315. The regulating member 317 can be kept in a regulatory position (shown in
The terminal 314 has a base portion 341, a flexible portion 342, a catch portion 343 (hook-shaped portion), a point 344 of contact, and the tip portion 345, disposed in this order from the side at which the terminal 314 is anchored to the bottom wall of the terminal 314. The terminal 314 is such a terminal that establishes an electrical connection between itself and the heater electrode 310 by being allowed to be moved into the slot 315X by its own resiliency. As the terminal 314 is allowed to move into the slot 315X, its point 344 of contact comes into contact with the electrode 310 of the heater 305. The point between the base portion 341 and flexible portion 342 functions as the pivot for the flexing of the terminal 314 (flexible portion 342). Referring to
The point 344 of contact is curved. It establishes an electrical connection between itself and the electrode 310 of the heater 305 by coming into contact with the electrode 310 as the connector 313 is engaged with the heater 305. It is kept pressed upon the electrode 310 by the resiliency of the above-described flexible portion 342. The tip portion 345 is a portion of the terminal 314, which prevents the terminal 314 from shifting, by being caught by the catch portion 346 of the housing 315.
The material for the connector terminal 314 is stainless steel or titanium alloy. The surface of the terminal 314 is plated with gold or the like substance, which is low in electrical resistance.
The regulating member 317 is in the housing 315. It has the terminal pressing portion 371, which extends in the direction indicated by the arrow mark X1 in
The regulating member 317 is solidly attached to the controller 318. The controller 318 is for moving the regulating member 317 in the regulating direction X1 or releasing direction X2. The controller 318, or the terminal controlling member, is provided with the protrusion 318a, which fits in the recess 315a or 315b of the housing 315. As the controlling member 318 is moved in the releasing direction X2 as far as it is allowed to move, the protrusion 318a fits into the recess 315b, allowing thereby the terminal 314 to protrude into the slot 315X so that as the connector 313 is engaged with the heater 305, the heater 105 enters the slot 315X and an electrical connection is established between the terminal 314 and the electrode 310 of the heater 305. On the other hand, as the controlling member 318 is moved in the regulating direction X1, its protrusion 318a fits into the recess 315a. When the protrusion 318a is in the recess 315a, the terminal 314 is outside the slot 315X (
a) is a perspective view of the combination of the heater 305 and the supporting member 306, and shows the overall structure of the combination.
Next, referring to
While the regulating member 317 is moved into the slot 315X, the pressing portion 371 of the regulating member 317 comes into contact with the flexible portion 342 of the terminal 314 and continues to press the flexible portion 342 downward, bending thereby the terminal 314 downward. As the regulating member 317 is moved further in the direction X1, the pressing portion 371 comes into contact with the catch portion 343 (hook-shaped portion). Meanwhile, the pressing portion 371 remains in contact with the parallel portion 343a. Then, as the controller 318 is moved as far as it can be moved in the direction X1, that is, until the front surface 318A of the controller 318 (
The connector 313 and its terminal 314 are structured so that while the pressing portion 371 is in contact with the horizontal portion 343a, the horizontal portion 343a remains roughly parallel to the direction X1 in which the pressing portion 371 is moved to regulate the terminal 314. Therefore, the regulating member 317 can be smoothly moved, that is, without being hung up by the terminal 314. As described above, the catch portion 343 has not only the horizontal portion 343a, but also, the vertical portion 343b, which is between the horizontal portion 343a and the point 344 of contact. The vertical portion 343b plays also a role of preventing the point 344 of contact from coming into contact with the pressing portion 371.
In this embodiment, the terminal 314 is pressed downward, and kept downwardly bent, by the regulating member 317. However, the connector 313 may be structured so that the terminal 314 can be pressed down, and kept downwardly bent, by a special tool; it does not need to have the regulating member 317 and the controller 318. In such a case, all that is necessary is to press downward the horizontal portion 343a of the terminal 314 with the special tool. More specifically, in a case where the connector is structured so that a special tool is used to downwardly bend the contact terminal, the housing 315 is provided with the second opening which allows the special tool to be inserted into the slot 315X, from the opposite direction from the direction in which the heater 305 enters the slot 315X. With the provision of the second opening, the special tool can be insert into the slot 315X to downwardly press the horizontal portion 343a of the catch portion 343 (hook-shaped portion) to bend the terminal 314 downward in order to move the point 344 of contact out of the slot 315X.
In this embodiment, the connector 313 is engaged with the supporting member 306 which is supporting the heater 305, while the terminal 314 is kept downwardly bent by the pressing portion 371 of the regulating member 317 (or the special tool), which presses downward the horizontal portion 343a of the catch portion 343 of the terminal 314. Therefore, while the connector 313 is engaged with the supporting member 306, a gap is present between the point 344 of contact and the heater 305, and therefore, the point 344 of contact and heater 305 do not rub against each other. Therefore, the heater electrode 310 and/or the point 344 of contact of the terminal 314 of the connector 313 is not frictionally worn during the engagement or disengagement of the connector 313. Therefore, an unsatisfactory electrical connection between the connector 313 and heater electrode 310, which is attributable to repeated engagement or disengagement of the connector 313, is unlikely to occur.
Further, the connector terminal 314 is provided with the hook-shaped portion (catch portion). Therefore, the amount by which the terminal 314 is bent downward by the regulating member 317 or special tool remains accurate. Therefore, it is ensured that the point 344 of contact of the terminal 314 of the connector 313 is not frictionally worn when the connector 313 is engaged with the heater 305.
The connector in this embodiment is suitable for supplying electric power to a two-sided heater, that is, a heater which has a heater (or heaters) and electrodes, on both surfaces of its ceramic substrate.
Referring to
The connector terminal 224 has: a base portion 241 by which the terminal 224 is held to the housing 223; a flexible portion 242 for providing the terminal 224 with resiliency; a catch portion 243 (hook-shaped portion); a point 244 of contact with curvature, and the tip portion 345, disposed in this order from the side at which the terminal is held to the housing 223. The housing 223 is provided with a catch 246, by which the tip portion 245 is caught. The catch portion 243 has a horizontal portion 243a and a vertical portion 243b. These portions of the contact terminal 224 are the same in function as the counterparts of the contact terminal 314 in the above-described fourth embodiment.
The connector 222 in this embodiment is also structured so that the point 244 of contact of one of the spring contacts of the terminal 224 opposes the other of the spring contacts. Thus, it is desired to prevent the problem that the plating of the point 244 of contact is changed in condition by the contact between the opposing two points 244 of contact. Therefore, the connector 222 is structured so that when the connector 222 is not in engagement with the heater 220 (as shown in
The regulating member 225 has two pressing portions 251, that is, the top and bottom pressing portions. The top pressing portion 251 presses the top terminal 224, and the bottom pressing portion 251 presses the bottom terminal 224.
In this embodiment, the connector 222 is engaged with the supporting member 221, which is supporting the heater 220, while the top and bottom terminals 224 are kept downwardly and upwardly bent by the top and bottom pressing portions 251, respectively, of the regulating member 225. Therefore, while the connector is engaged with the supporting member 221, a gap is present between the point 244 of contact and the electrode of the heater 220, and therefore, the point 244 of contact and the electrode of the heater 220 do not rub against each other. Therefore, the point 244 of contact is not frictionally worn. Therefore, an unsatisfactory electrical connection between the connector 222 and the heater electrode 220, which is attributable to the frictional wear of the point 244 of contact does not occur.
In the fourth and fifth embodiments, the connectors 313 and 222, respectively, are structured so that before the connectors 313 and 222 are engaged with the heater 305 and 220, the terminals 314 and 224 can be regulated by the regulating member or a special tool. Therefore, it does not occur that the points 344 and 244 of contact of the terminals 314 and 224 come into contact with the supporting members 306 and 221, respectively. Therefore, the phenomenon that the terminals 314 and 224 are permanently deformed by a substantial amount of load to which the points 344 and 244 of contact of the terminals 314 and 224 are subjected when the terminals 314 and 224 are engaged with the supporting members 306 and 221, respectively, and/or the phenomenon that the points 334 and 244 of contact are frictionally worn when the terminals 314 and 224 are engaged with the supporting members 306 and 221, respectively, does not occur. Therefore, a proper amount of contact pressure is generated and maintained between the points 334 and 244 of contact and the electrodes of the heaters 305 and 220, respectively.
Further, the terminals 314 and 224 are provided with a hook-shaped portion. Therefore, the amount by which they are resiliently bent by the regulating member or special tool is accurate. Therefore, it is ensured that the point of contact is not frictionally worn when the connector is engage with the heater.
Further, because the connectors in the fourth and fifth embodiments are structured as described above, a disassembler of the heating unit can disengage the connectors 313 and 222 without allowing the points 344 and 244 of contact to rub against the electrodes when the disassembler disassembles or reassemble the heating unit. Therefore, a reassembled connector is virtually the same in condition in terms of the electrical connection as it was before it was disassembled. That is, the connectors do not need to be adjusted in the state of electrical connection related to the performance of a fixing device, and therefore, are easier to maintain than a conventional connector.
While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.
This application claims priority from Japanese Patent Applications Nos. 109321/2012, 109322/2012 and 265482/2012 filed May 11, 2012, May 11, 2012 and Dec. 4, 2012, respectively, which are hereby incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-109321 | May 2012 | JP | national |
| 2012-109322 | May 2012 | JP | national |
| 2012-265482 | Dec 2012 | JP | national |
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| Number | Date | Country |
|---|---|---|
| 4585668 | Nov 2010 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20130302060 A1 | Nov 2013 | US |
