Patent Application
20180231931
The present invention relates to a fixing device and an image forming apparatus.
In recent years, the image forming apparatus is desired to enable output of a product correspondingly to various media, and a various media-compatible technique is needed. In the fixing device of the image forming apparatus, as one of the needed various media-compatible technique, prevention of generation of a “fixing (member) winding jam” such that various recording materials passed through a nip are wound about a fixing member without being separated from the fixing member is cited. In addition, a technique such that in the case where the “fixing winding jam” generated, immediate detection of the jam and stop of the fixing device is also a necessary technique. This is because it becomes more difficult to handle the recording material as it takes a longer time to detect the recording material and a proportion of a length of the recording material wound about the fixing member is larger when the fixing device stops.
In view of the above problem, Japanese Laid-Open Patent Application (JP-A) 2002-99174 proposes a fixing device in which a sheet discharge sensor for detecting the generation of the “fixing winding jam” is provided is proposed. By disposing the sheet discharge sensor in the neighborhood of a nip of a fixing member, in the case where the “fixing winding jam” generated, the jam can be detected early.
As disclosed in JP-A 2002-99174, in the case where the sheet discharge sensor is disposed inside the fixing device, a technique such that a sensor flag including a rotatable flag portion and a photo-interrupter switched in logic by light transmission/light blocking with the flag portion are used in combination is frequently employed. In such a constitution, assembling is required to be carried out so that the flag portion of the sensor flag enters an optical axis portion formed by a light emitting portion (light emitting element) and a light receiving portion (photosensor) of the photo-interrupter.
Further, it is not desirable that the photo-interrupter is disposed in a high temperature environment from the viewpoint of a heat-resistant property of an electric substrate mounted therein. In the fixing device of the image forming apparatus, a casing of the fixing device is provided with an opening and the flag portion is disposed outside the casing through the opening while disposing a detecting portion of the sheet discharge sensor in a feeding region of the recording material, and thus the photo-interrupter is disposed outside the casing which has a relatively low ambient (environmental) temperature in some cases. Further, the opening may desirably be set so as to be small to the extent possible in order to enhance strength and rigidity of the casing itself.
In the prior art, the assembling is carried out so that the flag portion of the sensor flag does not contact the photo-interrupter and the casing, i.e., a so-called “tilt assembling” is used frequently.
In recent years, in the image forming apparatus, in order to achieve a high quality and stable operation, it is required that a product is shipped in a further high-quality state. For that purpose, not only improvement in quality and performance of discrete component parts but also suppression of problems generating during assembling of the component parts and during maintenance in the market by a service person are important problems to be solved. Specifically, generation of deformation, breakage and the like of the parts due to unintentional contact with peripheral component parts when the parts are mounted is cited.
In the case where the sensor flag is subjected to the tilt assembling as in the prior art, in a mounting step thereof, when the sensor flag moves along a locus other than a proper locus, the sensor flag unintentionally contacts the photointerrupter and the peripheral component parts in some cases. As a result, there is a possibility that the above problems generate.
Further, use of a constitution in which the fixing device can be automatically assembled by an automatic machine in order to stably assembling the fixing device is also one of necessary techniques. In the case where the component parts are subjected to the tilt assembling by the automatic machine, there is a need to move the component parts with a high degree of freedom, so it becomes difficult for the automatic machine to ready for the tilt assembling. Alternatively, there is a problem such that a very expensive automatic machine such as a robot arm is required to be used.
A principal object of the present invention is to provide a fixing device and an image forming apparatus, in which a movable member including a flag portion movable between a light emitting portion and a light receiving portion of a detecting portion can be positioned relative to the detecting portion with high accuracy in an assembling operation thereof.
According to an aspect of the present invention, there is provided a fixing device comprising: first and second rotatable members forming a nip where a toner image on a recording material is formed; a movable member movable by arrival of the recording material at a predetermined position which is downstream of the nip with respect to a recording material feeding direction and which is within a passing region in which the recording material is passable with respect to a longitudinal direction of the first rotatable member, wherein the movable member includes a contact portion contactable to the recording material being in the predetermined position and includes a flag portion movable together with movement of the contact portion by the recording material contacting the contact portion; a first supporting side plate positioned outside the passing region with respect to the longitudinal direction and configured to rotatably support the first rotatable member, wherein the first supporting side plate including an opening having such a size that the flag portion is passable; a second supporting side plate positioned opposite from the first supporting side plate sandwiching the passing region therebetween with respect to the longitudinal direction and configured to rotatably support the first supporting side plate; a detecting portion including a light emitting portion and a light receiving portion and configured to detect the flag portion movable between the light emitting portion and the light receiving portion, wherein the detecting portion is positioned in an outside of the first supporting side plate with respect to the longitudinal direction, the outside being opposite from the passing region sandwiching the first supporting side plate between itself and the passing region with respect to the longitudinal direction; a supporting plate extending in the longitudinal direction so as to be connected with the first and second supporting side plates; a holding portion holding the movable member, wherein in a state that the holding portion holds the movable member, the holding portion is assembled with the supporting plate connected with the first and second supporting side plates; a slit portion configured to guide movement of the holding portion in a predetermined direction from the passing region toward the opening of the first supporting side plate so that the flag portion passes from the passing region through the opening in an assembling operation in which the holding portion is assembled with the supporting plate; a first projected portion configured to guide the movement of the holding portion in the predetermined direction in engagement with the slit; a second projected portion provided on the holding portion, wherein the second projected portion regulates a position of the holding portion relative to the supporting plate with respect to a height direction in contact with the supporting plate when the holding portion is moved in the predetermined direction by being guided by the slit portion and the first projected portion, the height direction being perpendicular to a holding portion supporting surface of the supporting plate; and a hole provided in the supporting plate, wherein the hole is disposed at a position where the second projected portion engages with the hole when the flag portion is positioned between the light emitting portion and the light receiving portion with respect to the longitudinal direction by movement of the holding portion in the predetermined direction by guidance of the slit portion and the first projected portion, wherein when the position of the holding portion with respect to the height direction is regulated by the second projected portion in contact with the supporting plate, in a projection plane in which the outside of the first supporting side plate is viewed in the longitudinal direction from a position between the light emitting portion and the receiving portion with respect to the longitudinal direction, the flag portion is accommodated inside the hole and is in a non-overlapping position with the detecting portion, and wherein when the projected portion is engaged in the hole, in the projection plane, the flag portion is in an overlapping position with the detecting portion.
According to another aspect of the present invention, there is provided a fixing device comprising: first and second rotatable members forming a nip where a toner image on a recording material is formed; a movable member movable by arrival of the recording material at a predetermined position which is downstream of the nip with respect to a recording material feeding direction and which is within a passing region in which the recording material is passable with respect to a longitudinal direction of the first rotatable member, wherein the movable member includes a contact portion contactable to the recording material being in the predetermined position and includes a flag portion movable together with movement of the contact portion by the recording material contacting the contact portion; a first supporting side plate positioned outside the passing region with respect to the longitudinal direction and configured to rotatably support the first rotatable member, wherein the first supporting side plate including an opening having such a size that the flag portion is passable; a second supporting side plate positioned opposite from the first supporting side plate sandwiching the passing region therebetween with respect to the longitudinal direction and configured to rotatably support the first supporting side plate; a detecting portion including a light emitting portion and a light receiving portion and configured to detect the flag portion movable between the light emitting portion and the light receiving portion, wherein the detecting portion is positioned in an outside of the first supporting side plate with respect to the longitudinal direction, the outside being opposite from the passing region sandwiching the first supporting side plate between itself and the passing region with respect to the longitudinal direction; a supporting plate extending in the longitudinal direction so as to be connected with the first and second supporting side plates; a holding portion holding the movable member, wherein in a state that the holding portion holds the movable member, the holding portion is assembled with the supporting plate connected with the first and second supporting side plates; a slit portion configured to guide movement of the holding portion in a predetermined direction from the passing region toward the opening so that the flag portion passes from the passing region through the opening in an assembling operation in which the holding portion is assembled with the supporting plate; a first projected portion configured to guide the movement of the holding portion in the predetermined direction in engagement with the slit; a second projected portion provided on the supporting plate, wherein the second projected portion regulates a position of the holding portion relative to the supporting plate with respect to a height direction in contact with the holding portion when the holding portion is moved in the predetermined direction by being guided by the slit portion and the first projected portion, the height direction being perpendicular to a holding portion supporting surface of the supporting plate; and a hole provided in the holding portion, wherein the hole is disposed at a position where the second projected portion engages with the hole when the flag portion is positioned between the light emitting portion and the light receiving portion with respect to the longitudinal direction by movement of the holding portion in the predetermined direction by guidance of the slit portion and the first projected portion, wherein when the position of the holding portion with respect to the height direction is regulated by the second projected portion in contact with the holding portion, in a projection plane in which the outside of the first supporting side plate is viewed in the longitudinal direction from a position between the light emitting portion and the receiving portion with respect to the longitudinal direction, the flag portion is accommodated inside the opening and is in a non-overlapping position with the detecting portion, and wherein when the projected portion is engaged in the hole, in the projection plane, the flag portion is in an overlapping position with the detecting portion.
According to another aspect of the present invention, there is provided an image forming apparatus comprising: an image forming portion configured to form a toner image on a recording material; first and second rotatable members configured to feed the recording material through a nip therebetween; a movable member movable by arrival of the recording material at a predetermined position which is downstream of the nip with respect to a recording material feeding direction and which is within a passing region in which the recording material is passable with respect to a longitudinal direction of the first rotatable member, wherein the movable member includes a contact portion contactable to the recording material being in the predetermined position and includes a flag portion movable together with movement of the contact portion by the recording material contacting the contact portion; a first supporting side plate positioned outside the passing region with respect to the longitudinal direction and configured to rotatably support the first rotatable member, wherein the first supporting side plate including an opening having such a size that the flag portion is passable; a second supporting side plate positioned opposite from the first supporting side plate sandwiching the passing region therebetween with respect to the longitudinal direction and configured to rotatably support the first supporting side plate; a detecting portion including a light emitting portion and a light receiving portion and configured to detect the flag portion movable between the light emitting portion and the light receiving portion, wherein the detecting portion is positioned in an outside of the first supporting side plate with respect to the longitudinal direction, the outside being opposite from the passing region sandwiching the first supporting side plate between itself and the passing region with respect to the longitudinal direction; a supporting plate extending in the longitudinal direction so as to be connected with the first and second supporting side plates; a holding portion holding the movable member, wherein in a state that the holding portion holds the movable member, the holding portion is assembled with the supporting plate connected with the first and second supporting side plates; a slit portion configured to guide movement of the holding portion in a predetermined direction from the passing region toward the opening of the first supporting side plate so that the flag portion passes from the passing region through the opening in an assembling operation in which the holding portion is assembled with the supporting plate; a first projected portion configured to guide the movement of the holding portion in the predetermined direction in engagement with the slit; a second projected portion provided on the holding portion, wherein the second projected portion regulates a position of the holding portion relative to the supporting plate with respect to a height direction in contact with the supporting plate when the holding portion is moved in the predetermined direction by being guided by the slit portion and the first projected portion, the height direction being perpendicular to a holding portion supporting surface of the supporting plate; and a hole provided in the supporting plate, wherein the hole is disposed at a position where the second projected portion engages with the hole when the flag portion is positioned between the light emitting portion and the light receiving portion with respect to the longitudinal direction by movement of the holding portion in the predetermined direction by guidance of the slit portion and the first projected portion, wherein when the position of the holding portion with respect to the height direction is regulated by the second projected portion in contact with the supporting plate, in a projection plane in which the outside of the first supporting side plate is viewed in the longitudinal direction from a position between the light emitting portion and the receiving portion with respect to the longitudinal direction, the flag portion is accommodated inside the hole and is in a non-overlapping position with the detecting portion, and wherein when the projected portion is engaged in the hole, in the projection plane, the flag portion is in an overlapping position with the detecting portion.
According to a further aspect of the present invention, there is provided an image forming apparatus comprising: an image forming portion configured to form a toner image on a recording material; first and second rotatable members configured through a nip therebetween; a movable member movable by arrival of the recording material at a predetermined position which is downstream of the nip with respect to a recording material feeding direction and which is within a passing region in which the recording material is passable with respect to a longitudinal direction of the first rotatable member, wherein the movable member includes a contact portion contactable to the recording material being in the predetermined position and includes a flag portion movable together with movement of the contact portion by the recording material contacting the contact portion; a first supporting side plate positioned outside the passing region with respect to the longitudinal direction and configured to rotatably support the first rotatable member, wherein the first supporting side plate including an opening having such a size that the flag portion is passable; a second supporting side plate positioned opposite from the first supporting side plate sandwiching the passing region therebetween with respect to the longitudinal direction and configured to rotatably support the first supporting side plate; a detecting portion including a light emitting portion and a light receiving portion and configured to detect the flag portion movable between the light emitting portion and the light receiving portion, wherein the detecting portion is positioned in an outside of the first supporting side plate with respect to the longitudinal direction, the outside being opposite from the passing region sandwiching the first supporting side plate between itself and the passing region with respect to the longitudinal direction; a supporting plate extending in the longitudinal direction so as to be connected with the first and second supporting side plates; a holding portion holding the movable member, wherein in a state that the holding portion holds the movable member, the holding portion is assembled with the supporting plate connected with the first and second supporting side plates; a slit portion configured to guide movement of the holding portion in a predetermined direction from the passing region toward the opening so that the flag portion passes from the passing region through the opening in an assembling operation in which the holding portion is assembled with the supporting plate; a first projected portion configured to guide the movement of the holding portion in the predetermined direction in engagement with the slit; a second projected portion provided on the supporting plate, wherein the second projected portion regulates a position of the holding portion relative to the supporting plate with respect to a height direction in contact with the holding portion when the holding portion is moved in the predetermined direction by being guided by the slit portion and the first projected portion, the height direction being perpendicular to a holding portion supporting surface of holding portion; and a hole provided in the supporting plate, wherein the hole is disposed at a position where the second projected portion engages with the hole when the flag portion is positioned between the light emitting portion and the light receiving portion with respect to the longitudinal direction by movement of the holding portion in the predetermined direction by guidance of the slit portion and the first projected portion, wherein when the position of the holding portion with respect to the height direction is regulated by the second projected portion in contact with the holding portion, in a projection plane in which the outside of the first supporting side plate is viewed in the longitudinal direction from a position between the light emitting portion and the receiving portion with respect to the longitudinal direction, the flag portion is accommodated inside the opening and is in a non-overlapping position with the detecting portion, and wherein when the projected portion is engaged in the hole, in the projection plane, the flag portion is in an overlapping position with the detecting portion.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Part (a) of
Part (a) of
Parts (a) and (b) of
Parts (a), (b) and (c) of
Parts (a) and (b) of
Parts (a), (b) and (c) of
Parts (a), (b) and (c) of
Parts (a), (b) and (c) of
Parts (a), (b) and (c) of
Embodiments of the present invention will be specifically described with reference to the drawings.
The printer shown in
On the other hand, the recording material P is fed one by one from a state feeding cassette 4 and passes through a post-sheet feeding path 45, and is sent to a registration roller pair 9. The registration roller pair 9 once receives the recording material P, and in the case where the recording material P obliquely moves, the registration roller pair 9 rectifies the oblique movement of the recording material P so as to move straight. Then, the registration roller pair 9 sends the recording material P to between the intermediary transfer belt 2 and a secondary transfer roller 3a in synchronism with the toner images on the intermediary transfer belt 2.
The toner images on the intermediary transfer belt 2 are transferred onto the recording material P by, for example, the secondary transfer roller 3a which is a transferring member. Thereafter, the toner images on the recording material P pass through a pre-fixing feeding path 30, and the recording material P is heated and pressed by a fixing device 40, so that the toner images are fixed on the recording material P.
In the case where the toner image is formed on only one surface of the recording material P, the recording material P is discharged onto a sheet discharge tray 12 through a sheet discharging roller pair 11 by switching of a switching flapper 46. In the case where the toner images are formed on both surfaces of the recording material P, the recording material P on which the toner image is fixed is fed in a vertical direction by the fixing device 40 and then is further fed by the sheet discharging roller pair 11. Then, when a trailing end of the recording material (paper) P reaches a reversing point 42, the recording material P is fed in a switch-back manner by reverse rotation of the sheet discharging roller pair 11.
Then, after the recording material P is passed through a feeding path 47 for double-side printing by the switching flapper 46, a process similar to that of one-side printing (image formation) is performed, so that the toner image is formed on the other surface (side) of the recording material P and then the recording material P is discharged onto the sheet discharge tray 12. Incidentally, a portion constituted by the flapper 46 and the sheet discharging roller pair 11 which are used in a switch-back operation is an example of a reversing means.
For the purposes of removal of the recording material P during a jam in the feeding path and of maintenance and the like, an apparatus main assembly is provided with a door 80 so as to be rotatable about a hinge 90 toward a right side in
An urging (pressing) spring 115 (
That is, the urging force transmitted to the flanges 116 acts on both end portions of the metal stay 114 ((b) of
That is, as shown in (b) of
At the fixing nip N, a fixing film 113 as a rotatable member is flexed by being sandwiched between the heater 111 and the pressing roller 120 as an opposing member (rotatable member) by a pressing force, so that the fixing film 113 is in a state of hermetic contact with a heating surface of the heater 111. The pressing roller 120 receives a driving force, from an unshown motor, for rotating the pressing roller 120 in a direction of an arrow in (a) of
With this rotational drive of the pressing roller 120, the fixing film 113 is rotated (moved) by a frictional force with the pressing roller 120. At this time, the fixing film 113 slides on the heater 111. Between the fixing film 113 and the heater 111, a lubricant such as a heat-resistant grease of a fluorine-containing type or a silicone type is interposed, whereby a frictional resistance is suppressed to a low level, so that the fixing film 113 is smoothly rotatable (movable).
Further, temperature control of the heater 111 is carried out depending on signals of a through detecting element such as a thermistor 118 or the like provided on a back surface of a ceramic substrate thereof and a temperature detecting element such as a thermistor 119 or the like provided, for directly detecting a temperature of the fixing film 113, on an inner surface of the fixing film 113. That is, an unshown heater controller determines and properly controls a duty ratio, a wave number and the like of a voltage applied to an energization heat generating resistance layer, whereby a temperature in the fixing nip N is maintained at a predetermined set temperature.
Further, the metal stay 114 is provided with a grounding means 121 ((b) of
The fixing device 40 includes an inner sheet discharging roller pair (feeding roller pair) 70 as shown in
In order to suitably maintain an attitude of the fed recording material P, the inner sheet discharging driving roller 70a is rotated at a speed set so as to be higher, for example, about 0-5% than a rotational speed of the pressing roller 120. The inner sheet discharging roller pair 70 may desirably be brought near to the fixing nip N to the extent possible. This is because the recording material P discharged from the fixing nip N is maintained early in a suitable attitude to the extent possible and thus a product quality is improved.
Further, inside the fixing device 40, a sheet discharge sensor (sensor flag, movable member) 133 including a flag portion 133c described later is provided. The sheet discharge sensor 133 is, as shown in
The recording material P on which an unfixed toner image is held is appropriately fed along an entrance guide 128 (
The sheet discharge sensor (sensor flag) 133 in this embodiment will be specifically described with reference to parts (a) and (b) of
In this embodiment, as shown in part (a) of
The sheet discharge sensor 133 further includes a sheet discharge sensor flag portion 133c for blocking the incident light into the sensor portion 144a of the photosensor 144 by rotation. In addition, the sheet discharge sensor 133 includes an abutting portion 133d of which rotation attitude is regulated by being abutted against an abutting portion 135b ((a) of
In this embodiment, as shown in parts (a) and (b) of
In the case where a jam of the recording material P occurs in the fixing nip N, it is desirable that the sheet discharge sensor 133 early detects the recording material P and the fixing device is stopped due to emergency. In this embodiment, diameters of the fixing film 113 and the pressing roller 120 are set at about 30 mm, and the sheet discharge sensor 133 is disposed at a position of about 15 mm from the fixing nip N so as to be capable of detecting arrival of the recording material P.
Structures of the sheet discharge sensor 133 and the sheet discharge sensor holder 135 for holding the sheet discharge sensor 133 will be specifically descried using
For simplification of explanation, in the following, a pressing (urging) direction of the fixing nip N is referred to as an “X direction”, a widthwise direction of the recording material P (longitudinal direction of the fixing member) is referred to as a “Y direction”, and the feeding direction of the recording material P is referred to as a “Z direction”.
Parts (a), (b) and (c) of
Further, in order to enhance strength and rigidity of the fixing device 40, a reinforcing stay (supporting plate) 143 as a casing extends in the widthwise direction (Y direction) of the recording material P and is provided between the front side plate 141 and the rear side plate 142 and is fastened by a means such as unshown screws or welding. The front side plate 141, the rear side plate 142 and the supporting plate 143 are made of a metallic material.
With the front side plate 141, the photosensor 144 mounted on a photosensor holder 145 is assembled. The photosensor 144 and the photosensor holder 145 are disposed on a side opposite from a feeding path of the recording material P with respect to the front side plate 141. This is because the influence by heat, paper powder, contamination with a wax, and the like, which generate in the fixing device 40 is reduced.
The sheet discharge sensor unit 13 is disposed so as to extend toward an outside through an opening 141c provided in the front side plate 141 so that the flag portion 133c projects on the photosensor 144 side positioned on the outside of the front side plate 141. In the sheet discharge sensor unit 13, a fixing portion 135c provided on the sheet discharge sensor holder 135 is fixed to the reinforcing stay 143 by an unshown fixing means such as a screw.
Detailed structures of the sheet discharge sensor unit 13 and the reinforcing stay 143 will be described with reference to
On the other hand, the reinforcing stay 143 which is the casing is provided with round holes 143a and 143b ((a) of
In an assembled state, the height regulating bosses 135d and 135e of the sheet discharge sensor holder 135 are disposed at positions corresponding to positioning holes 143a and 143b, respectively, as positioning portions of the reinforcing stay 143. A diameter of the positioning hole 143a is set so as to be larger by about several tens of μm than a diameter of the height regulating boss 135d and performs a function of determining a position of the sheet discharge sensor unit 13 with respect to the X direction and the Y direction when the height regulating boss 135d engages in the associated positioning hole 143a.
On the other hand, a diameter of the positioning hole 143b is set so as to be larger by about several mm than a diameter of the height regulating boss 135e and so as not to contact the height regulating boss 135e when the height regulating boss 135e engages in the associated positioning hole 143b ((c) of
At free end portions of the height regulating bosses 135d and 135e, as shown in part (a) of
Further, in part (c) of
Further, as shown in part (c) of
Further, as shown in (b) of
Side (movement) of the sheet discharge sensor holder 135 will be described. The slide assisting grooves 135f and 135g of the sheet discharge sensor holder 135 are provided correspondingly to the slide assisting portions 143c and 143d of the reinforcing stay 143 and is constituted so as to be slidable (movable) in the Y direction. That is, the reinforcing stay 143 as the casing includes the slide assisting portions 143c and 143d as portions-to-be-regulated correspond to the slide assisting grooves 135f and 135g as first regulating portions, respectively.
Specifically, as shown in part (b) of
Thus, the slide assisting groove 135f successively includes the first region (135fb) for regulating the sheet discharge sensor holder 135 with first accuracy and the second region (135fa) for regulating the sheet discharge sensor holder 135 with second accuracy higher than the first accuracy.
Further, a width of the slide assisting groove 135g with respect to the X direction is set so as to be larger by about several hundreds of μm than a width of the slide assisting portion 143d with respect to the X direction. Further, during assembling, the slide assisting groove 135g is constituted by a slide assisting groove-positioning portion (positioning groove portion) 135ga, for regulating rotation of the sheet discharge sensor holder 135 in X-Y direction with a latitude and by a slide assisting groove-roughly guide portion (guiding groove portion) 135gb. The guiding groove portion 135gb is set so as to be larger by about several mm than the width of the slide assisting portion 143c with respect to the X-direction, so that guidance of the slide assisting portion into the positioning groove portion 135ga is prompted.
Thus, the slide assisting groove 135g successively includes the first region (135gb) for regulating the sheet discharge sensor holder 135 with first accuracy and the second region (135ga) for regulating the sheet discharge sensor holder 135 with second accuracy higher than the first accuracy.
Here, in the slide (movement) of the sheet discharge sensor holder 135 in the −Y direction, when the flag portion 133c passes through the opening 141c of the front side plate 141 and the photosensor 144, attitudes of the sheet discharge sensor holder 135 and the sheet discharge sensor 133 may desirably be stable in a regulated state.
Therefore, when the flag portion 133c passes through the opening 141c of the front side plate 141 and the photosensor 144, the state of the sheet discharge sensor holder 135 and the sheet discharge sensor 133 is changed from a roughly guided state by the guiding groove portions 135fb and 135gb to a guided state by the positioning groove portions 135fa and 135ga.
As shown in part (a) of
In this embodiment, the distances E and F ((a) of
An assembling method (adjusting method, manufacturing method) of the sheet discharge sensor unit 13 by the sensor flag adjusting unit in this embodiment will be described using
A general outline of the assembling method (manufacturing method) is shown by arrows in part (a) of
First, as shown in part (c) of
Here, the heights of the height regulating bosses 135d and 135e and the opening amount of the opening 141c of the front side plate 141 which are shown in (b) of
Then, the sheet discharge sensor unit 13 is slid in the −Y direction so that the flag portion 133c moves toward the photosensor 144 (
Then, until the flag portion 133c reaches the opening 141c of the front side plate 141, the sheet discharge sensor unit 13 is in a state of being guided by the slide assisting groove positioning portion 135fa and the slide assisting groove guiding portion 135ga ((c) of
When the sheet discharge sensor holder 135 is further moved in the −Y direction from the state of
The Y direction distance C between the center of the height regulating boss 135d and the flag portion 133c and the Y direction distance D between the center of the positioning hole 143a of the reinforcing stay 143 and a Y direction center (intermediary position between the light emitting element and the sensor) of the optical axis of the photosensor 144, which distances C and D are shown in part (b) of
By employing the constitution of this embodiment, in the assembling operation of the movable member including the flag portion movable between the light emitting portion and the light receiving portion of the detecting portion, it is possible to provide the fixing device capable of positioning relative to the detecting portion with accuracy. Specifically, by using the constitution of this embodiment, as described above, the sheet discharge sensor unit 13 can be assembled without unintentional contact of the sheet discharge sensor unit 13 with peripheral component parts. Further, a movement locus of the sheet discharge sensor can be regulated to a minimum, and therefore, the opening amount W1 of the opening 141c of the front side plate 141 can be minimized, so that strength and rigidity of the front side plate 141 can be enhanced to a maximum. In addition, the sheet discharge sensor unit 13 can be assembled in a minimum necessary space only by a combination of translational motions, so that it is also possible to meet assembling by an inexpensive automatic machine without using the tilt assembling as in the prior art.
In the above, a preferred embodiment of the present invention was described, but the present invention is not limited thereto, but can be modified and changed variously within a range of the scope of the present invention.
In the above-described embodiment, two height regulating bosses 135d and 135e and two positioning holes 143a and 143b were used, but are used for stabilizing the attitude of the sheet discharge sensor holder 135, and therefore three or four height regulating bosses and three or more positioning holes may also be used. Further, a single height regulating boss and a single positioning hole may also be employed. In this case (where the single height regulating boss and the single positioning hole are employed), in order to stabilize the attitude of the sheet discharge sensor holder 135, a contact area of the free end portion of the height regulating boss 135d may preferably be increased.
Further, similarly, two slide assisting grooves 135f and 135g and two slide assisting portions 143c and 143d were also used, but three or more slide assisting grooves and three or more slide assisting portions may also be used. Further, a single slide assisting groove and a single slide assisting portion may also be employed. In this case (where the single slide assisting groove and the single slide assisting portion are employed), in order to stabilize the attitude of the sheet discharge sensor holder 135, an auxiliary length of each of the slide assisting portion 143c and the slide assisting groove 135f may preferably be increased.
In the above-described embodiment, the constitution in which the sensor holder 135 is provided with the height regulating bosses 135d and 135e and the reinforcing stay 143 is provided with the positioning holes 143a and 143b was employed, but the shapes of the projected portions and recessed portions may also be an opposite relationship when the regulation with respect to the height direction and the rotational direction can be carried out. That is, a constitution in which one of the second regulating portion 135d and the positioning portion 143a is the projected portion and the other portion is the recessed portion may only be required to be employed. Specifically, a constitution in which the sensor holder 135 is provided with the positioning holes 143a and 143b and the reinforcing stay 143 is provided with the height regulating bosses 135d and 135e may also be employed.
In the above-described embodiment, the cross-section of each of the height regulating bosses 135d and 135e in the X-Y plane is illustrated as a circular projected portion, and each of the positioning holes 143a and 143b is illustrated as a circular hole. However, the shapes of the height regulating bosses and the positioning holes may also be other shapes when a constitution in which the height regulating bosses 135d and 135e engage in the positioning holes 143a and 143b is employed.
In the above-described embodiment, the height regulating bosses 135d and 135e and the slide assisting grooves 135f and 135g were provided separately in other shapes, but the height regulating function and the slide assisting function may also be achieved by a single stepwise shape portion.
As regards the photosensor 144, in the −Y direction, the front side plate 141, the sensor portion 144a and the light emitting portion 144b were arranged in the named order. However, as regards the arrangement of the photosensor 144, with respect to the Y direction, a positional relationship between the sensor portion 144a and the light emitting portion 144b may also be reversed (inverted). That is, in the −Y direction, the front side plate 141, the light emitting portion 144b and the sensor portion 144a may also be arranged in the named order. In this case, in the movement of the sheet discharge sensor holder 135 in the −Y direction in the above-described operation, the height regulating bosses 135d and 135e regulates the Z direction position of the sheet discharge sensor holder 135 so that the flag portion 133c does not abut against the light emitting portion 144b.
The opening 141c of the front side plate 141 has a hole shape (hole penetrating the front side plate 141 in the Y direction) such that an edge of the opening is connected thereto. However, the present invention is not limited thereto when a constitution in which in the movement of the sheet discharge sensor holder 135 in the −Y direction in the assembling operation, the flag portion 133c does not abut against the surface of the front side plate 141 is employed. For example, a U-shaped opening which opens in the X direction may also be used.
In the above-described embodiment, the constitution in which the sheet discharge sensor unit 13 was assembled with the front side plate 141, the rear side plate 142 and the reinforcing stay 143 which rotatably support the pressing roller 120 was described. The present invention may also be applied to a constitution in which the sheet discharge sensor unit 13 is assembled with a front side plate, a rear side plate and a reinforcing stay which rotatably support the inner sheet discharging roller pair 70.
The photosensor 144 was disposed on the front side plate 141 side, but may also be disposed on the rear side plate 142 side. Further, the relationship among the X direction, the Y direction and the Z direction is not limited to that in the above-described embodiment, but may also be a relationship such that the X, Y and Z directions are replaced with each other when a directional relationship in the assembling of the sheet discharge sensor holder 135 with the reinforcing stay 143 is the same relationship.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Applications Nos. 2017-022990 filed on Feb. 10, 2017 and 2017-236984 filed on Dec. 11, 2017, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-022990 | Feb 2017 | JP | national |
| 2017-236984 | Dec 2017 | JP | national |
