JP2005077684A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible for an operator to easily perform jamming elimination even in the case a sheet of paper passes through a separation pawl and causes jamming, to prevent the breakage of the separation pawl in the midst of jamming elimination work, and to prevent the operator from being injured with the separation pawl. <P>SOLUTION: A paper carrying path 69 extending from the fixing part of a fixing device 14 to a paper discharge part is constituted of guide members, and a main guide member 72A serving as one of the guiding members is arranged so that it can rotate around a shaft 73 functioning as a fulcrum. A stay member 79 having the separation pawl 81 as a single body and a protecting member 78 are arranged so as to rotate around the shaft 73 functioning as a fulcrum. According to the linkage of a guide groove 82 formed on the stay member 79 and a projecting part 85 formed on the protecting member 78 side and engaged with the guide groove 82, the stay member 79 rotates at the same time when the main guide member 72A rotates. However, the protecting member 78 starts to rotate after the separation pawl 81 is completely stored, and finally, the protecting member 78 is held in a position shown by a two-dot chain line, and the jamming elimination cavity is secured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a plotter.

In this type of image forming apparatus, an electrostatic latent image is formed on an image carrier based on target image information, the electrostatic latent image is visualized as a toner image by a developing unit, and the toner image is transferred. The image is transferred onto a sheet (sheet-like recording medium) by means, the sheet holding the image is guided to the fixing device and fixed, and then discharged from a predetermined discharge portion (discharge port).
Generally, the fixing device includes a fixing roller and a pressure roller that is in pressure contact with the fixing roller. Fixing separation claw (hereinafter, also simply referred to as “separation claw”) is provided to prevent the fixed paper from being closely separated from the fixing roller and rolling up as the fixing roller rotates. ing. Usually, the separation claw has a sharp tip shape and is pressed against the surface of the fixing roller by a biasing means.

Japanese Patent Laid-Open No. 8-220923 discloses a configuration in which a plurality of fixing separation claws provided in a fixing device can be moved toward and away from the outer peripheral surface of a fixing roller all at once. By reducing the number of components, low cost, easy assembly, and space saving are achieved.
Japanese Patent Laid-Open No. 2000-219383 includes a protective member having a non-sharp tip shape with respect to the fixing separation claw and protruding toward the paper passing side, and the protective member is made of a paper that is jammed. A configuration is disclosed in which the pushing-up configuration does not apply an extra load to the fixing separation claw and prevents the claw from being damaged and the fixing roller from being damaged.

JP-A-8-220923 JP 2000-219383 A

In this type of image forming apparatus, the paper that is in close contact with the fixing roller may pass through the surface of the fixing roller and the separation claw, resulting in a jam. In such a case, the separation claw is separated from the fixing roller, and the jam processing is performed after securing the processing space. However, the sharp tip of the separation claw contacts the operator during the processing operation. There is a risk that the operator may be injured or the separation claw may be damaged.
In the configuration described in Japanese Patent Laid-Open No. 8-220923, by reducing the number of components, the cost can be reduced, the assembly can be facilitated, and the space can be saved. The above-mentioned concerns could not be resolved because the area was still exposed.
In the configuration described in Japanese Patent Laid-Open No. 2000-219383, the fixing separation claw is not easily separated from the fixing roller. Therefore, when a separation failure occurs in the fixing separation claw and the paper is wound around the fixing roller. Therefore, there is a situation where a sheet exists between the surface of the fixing roller and the fixing separation claw. If the paper jam process is performed in this state, there are problems such as damage to the nail because the fixing separation claw is not separated, and a sheet that is damaged by being caught by the nail exists as remaining paper.

  Therefore, according to the present invention, it is possible to easily perform the jam processing even when the paper passes through the separation claw and the jam occurs, and the separation claw is damaged during the jam processing operation or the operator is injured by the separation claw. An object of the present invention is to provide an image forming apparatus that does not have the risk of causing or failure.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a fixing separation member for separating the sheet-like recording medium from the surface of the fixing member of the fixing device for fixing the image, and the fixed shaft is a fulcrum. The fixing separation member is attached to a stay member provided so as to be rotatable, and the fixing separation member is provided so as to be able to contact with and separate from the fixing member by rotating the stay member. When the fixing separation member is moved away from the fixing member, the protective separation member is provided so as to cover the fixing separation member.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the protective member constitutes a part of a conveyance path from the fixing part to the discharge part, and the fixing separation member is separated from the fixing member. In accordance with the operation, the protective member is also displaced to a position where the transport path is opened.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the protective member is provided so as to be rotatable and displaceable, and the rotation fulcrum of the stay member is shared.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the rotation position of the stay member for separating the fixing separation member from the fixing member is limited, and the protective member is the fixing member. Displacement starts after the separating member is completely accommodated.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the conveyance path from the fixing part to the discharge part faces the front and back surfaces of the sheet-like recording medium. It is constituted by a member, and one of these guide members is rotatably provided so as to open the transport path, and the stay member rotates as the one guide member rotates. And

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the stay member is fixed to the one guide member.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the protective member is formed of a synthetic resin.

  According to the first aspect of the present invention, the fixing separation member for separating the sheet-like recording medium from the surface of the fixing member of the fixing device for fixing the image is provided, and is rotatable about the position-fixed shaft. The fixing / separating member is attached to the provided stay member, and the fixing / separating member is detachably provided with respect to the fixing member by rotating the stay member, and the stay member is rotated to rotate the stay member. When the fixing / separating member is separated from the fixing member, the protective separating member is provided so as to cover the fixing / separating member. This can prevent problems such as burns and damage to the fixing separation member.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the protective member constitutes a part of a conveyance path from the fixing part to the discharge part, and the fixing separation member is separated from the fixing member. The protective member is also displaced to a position where the conveying path is opened in accordance with the separation operation, so that the fixing separation member can be housed and protected using the existing components, and the number of parts is increased. The above problems can be prevented at low cost without any problems.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the protective member is provided so as to be rotatable and displaceable, and the rotation fulcrum of the stay member is shared. A protective function of the fixing / separating member can be obtained with a simple structure.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the rotation position of the stay member for separating the fixing separation member from the fixing member is limited, and the protection member is Since the displacement starts after the fixing / separating member is completely accommodated, it is possible to completely prevent the operator from touching the fixing / separating member during the jam processing.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the conveyance path from the fixing portion to the discharge portion faces the front and back surfaces of the sheet-like recording medium. The guide member is configured such that one of these guide members is rotatably provided so as to open the conveyance path, and the stay member is rotated in accordance with the rotation of the one guide member. Therefore, the opening of the conveyance path and the separation operation and protection of the fixing separation member can be performed at the same time, and the jam handling operation can be facilitated and speeded up.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, since the stay member is fixed to the one guide member, the conveyance path is opened and the fixing separation is performed with a simple structure. The separation operation and protection of the members can be performed simultaneously.

According to the seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the protective member is formed of a synthetic resin.
It can suppress that a protection member becomes high temperature, and can prevent a worker touching and doing a burn etc. Further, the manufacturing cost can be reduced by integral molding.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an external view of a digital copying machine as an image forming apparatus according to the present embodiment. In FIG. 1, the digital copying machine 1 includes a sheet-like recording medium (including concepts of paper, recording paper, transfer paper, etc.). Is configured so that it can be discharged to a discharge tray 62 as a permanent discharge destination provided in the internal space of the apparatus, so-called in-body discharge is possible.
As shown in FIG. 2, the digital copying machine 1 includes a copying machine main body (image forming apparatus main body) 18, an automatic document feeder (ADF) 13, a paper discharge tray 19, a paper supply bank P2, and the like. .

The automatic document feeder 13 feeds documents stacked on the document feeder 101 one by one onto the contact glass P3A on the copying machine main body (image forming apparatus main body) 18 side, and after reading the image, the paper discharge tray 13A. It is configured to discharge the paper upward.
The document on the document feeder 101 is aligned in the width direction by a side fence (not shown), separated from the lowermost document by a pair of feed rollers 102, and fed onto the contact glass P3A by the conveyor belt 103. Paper.
The feeding unit 107 includes a document detection sensor 108 and a document length detection sensor 109. By these sensors, the size of the document sent from the automatic document feeder 13 is detected. The original on the contact glass P3A is discharged onto the discharge tray 13A by the conveying belt 103 and the discharge roller pair 104 after the reading is completed.

  When reading a double-sided document, the document on the document feeder 101 is separated from the lowermost document by the pair of feed rollers 102 and fed, and is reversed by the transport belt 103 over the contact glass P3A. It is reversed by the nail 106, fed again onto the contact glass P3A, and the back surface is read. Next, the original on the contact glass P3A is transported by the transport belt 103 after being read from the back surface, reversed by the reversing claw 106, fed again onto the contact glass P3A, and the front surface is read. Then, the original after the front side reading is discharged onto the paper discharge tray 13A by the conveyance belt 103 and the paper discharge roller pair 104.

The copying machine main body 18 includes a document scanning unit (scanner) P3 that reads a document, an image formation processing unit P1, a plotter, and the like. The document scanning unit P3 includes a contact glass P3A for placing a document and an optical scanning system 12. The optical scanning system 12 includes an exposure lamp 20, a first mirror 21, a second mirror 22, a third mirror 23, and a lens 24. And a full-color CCD 25 and the like.
The exposure lamp 20 and the first mirror 21 are mounted on the first carriage, and the first carriage moves in the sub-scanning direction at a constant speed by a stepping motor when reading a document. The second mirror 22 and the third mirror 23 are mounted on the second carriage, and the second carriage moves at a speed half that of the first carriage by a stepping motor when reading a document. The original on the contact glass P3A is optically scanned by the movement of the first and second carriages, and is imaged on the light-receiving surface of the full-color CCD 25 by the lens 24 and subjected to photoelectric conversion.

The image signal separated into red (R), green (G) and blue (B) by the full color CCD 25 is A / D converted by an image processing circuit, and then subjected to various image processing by an image processing unit. The electrostatic latent image is formed by the writing device 4.
The writing device 4 includes a laser output unit, an fθ lens, a mirror, and the like. The laser output unit includes a laser diode (LD) that is a laser light source, a polygon mirror, a polygon motor, and the like. The laser output unit emits a black signal laser beam modulated according to the image read by the scanner during copying, and forms a latent image on the photosensitive member 2.
Around the photosensitive member 2, a charging device 3, a writing device 4, a developing device 5, a transfer device 6 and a cleaning device 7 for sequentially executing image forming processing along the clockwise direction that is the rotation direction thereof are arranged. Has been.
In the present embodiment, the writing device 4 has a configuration capable of forming latent images for forming images of different colors, that is, two writing optical paths, and the developing device 5 is also formed by the writing device 4. Two types of developing devices (for the sake of convenience, writing light is indicated by reference numerals 4 and 4 ′ and developing devices are indicated by reference numerals 5 and 5 ′) are provided so as to supply a developer of a color corresponding to the latent image. ing. For example, the developing device 5 contains black toner, and the developing device 5 ′ contains red toner.

The paper feed bank P2 is fed out from any of the paper feed cassettes P2A to P2B containing the paper of the size selected toward the registration roller pair 8 arranged in front of the transfer position in the image forming processing unit P1. This is the part that can be fed. For this reason, the sheet feeding bank P2 feeds one sheet by using the feeding roller 9 on the exit side of the plurality of sheet feeding cassettes P2A to P2B, and by reversely rotating one of the sheet feeding cassettes P2A to P2B. A possible pair of separation rollers 10 and a pair of feed rollers 11 for feeding a sheet that is fed one by one are arranged.
The toner image formed on the photoreceptor 2 is transferred to a sheet. The paper is selectively fed from one of the plurality of paper feed cassettes P2A to P2B.

The sheet hits the registration roller pair 8 after a predetermined time after the leading edge is detected by the registration sensor 52, temporarily stops, and is conveyed by the registration roller pair 8 in synchronization with the sub-scanning effective period signal (FGATE). 2 is transferred by the transfer device 6. The transfer device 6 includes a conveyance belt and can also serve as a sheet suction conveyance unit. A sheet on which a toner image carried on the photosensitive member 2 is transferred while being conveyed by the conveyance belt is transferred to the transfer device 6. After passing through the device 6, the toner image is fixed by being introduced into the fixing device 14.
The paper after fixing is discharged to the paper discharge tray 19 through the conveyance roller pair 56, the switching claw 57, the conveyance roller pair 58, the switching claw 59, and the paper discharge roller pair 60 during single-sided printing and after double-sided printing.
The paper after the front surface printing at the time of duplex printing is guided to the reverse conveyance path 41 by the switching claw 57, is switched back by the reverse conveyance roller, is reversed, and is conveyed to the double-sided paper refeed conveyance path 42. The sheet conveyed to the double-sided refeed conveyance path 42 is conveyed longitudinally by the feeding roller 16 toward the registration roller pair 8 to form an image on the back surface.

As shown in FIG. 2, a discharge unit (bin tray) 69 as a detachable discharge destination can be arbitrarily added above the discharge tray 62 in the internal space of the copier body 18. When the paper discharge tray 19 is not used and the paper discharge unit 69 is added, the paper that has passed through the fixing device 14 is guided to the paper discharge tray 62 or the paper discharge unit 69 by the transport path switching unit 15 extending in the vertical direction. The
The conveyance path switching unit 15 is provided in a conveyance unit denoted by reference numeral 17 in FIG. 2 together with a feeding roller 16 that feeds paper to the photosensitive member 2, a registration roller pair 8, a transfer device 6, and a fixing device 14. The transport unit 17 is slidable (movable in and out) between the storage position and the pull-out position in the direction orthogonal to the transport direction with respect to the copying machine main body 18 by a slide guide member denoted by reference numeral TR in FIG. Yes.

  The pull-out direction of the transport unit 17 in the present embodiment corresponds to the side where the operator faces the operation panel 1B of the image forming apparatus. Thus, when the transport unit 17 is pulled out, as shown in FIG. The fixing device 14 and the conveyance path switching unit 15 are exposed to the outside. Therefore, a jam occurring in the transport path switching unit 15 can be processed by the operator on the side facing the normal image formation. In FIG. 3, reference numeral 1A denotes a door that can be opened and closed provided in the digital copying machine 1, and is normally closed as shown in FIG. It is opened when 17 is pulled out.

As shown in FIG. 4, the transport unit 17 is positioned with respect to the copying machine main body 18 at positions E and F on a main body side plate (not shown). The fixing device 14 mounted on the transport unit 17 is positioned at positions G and H in the direction perpendicular to the transport direction with respect to the transport unit 17, but is not positioned in the transport direction. When the transport unit 17 is mounted on the copying machine main body 18, it is positioned on the main body side plate by the positioning pins I and J.
The transfer device 6 is driven in the direction of the arrow 37 by a lifting motor (not shown), and is set at a position apart from the photosensitive member 2 except for printing (when jamming or the like). In FIG. 4, the conveyance path switching unit 15 is omitted.
The transport unit 17 in the present embodiment is configured by integrally forming a structure that supports each unit (device), a transport guide that guides paper, and the like with resin.
In FIG. 4, reference numeral 50 denotes a double-sided conveying means, reference numeral 46 denotes a conveying roller pair, reference numeral 47 denotes a refeed roller pair, and reference numeral 49 denotes a conveying roller pair.

As shown in FIG. 5, the transport unit 17 is provided so as to be able to be inserted and removed freely in front of the copying machine body 18 and in the rear side direction (the direction of the arrow 66). In FIG. 5, reference numeral 18 a indicates the bottom surface of the receiving unit 17 housing recess, and 18 b indicates the back side of the housing recess.
The transport unit 17 and the copying machine main body 18 are electrically connected by a plurality of harnesses 64 (only one is shown in FIG. 5), and the transport unit 17 can be controlled. The plurality of harnesses 64 are drawn from an opening 63 formed on the back side surface 18 b of the copying machine main body 18. The wire length of the harness 64 has a sufficient margin with respect to the distance (movement distance) to which the transport unit 17 is drawn, and these harnesses 64 bend in the direction of the arrow 65 as the transport unit 17 is put in and out.
In the present embodiment, the plurality of harnesses 64 are guided and protected by a harness guide member (not shown).

Next, based on FIGS. 6 and 7, a conveyance path from a fixing part (a part where fixing is performed by the fixing device 14) to a discharge part (a paper discharge port) will be described. In the following description, the paper is discharged only to the permanent paper discharge tray 62.
A sheet conveyance path 69 between the fixing portion and the sheet discharge port is configured by a first guide member 70 and a second guide member 72 that face the front and back surfaces of the sheet. The sheet guided to the sheet conveyance path 69 is nipped and conveyed by a plurality of conveyance roller pairs 71. The first guide member 70 side is provided with a driving roller that forms one of the conveying roller pair 71, and the second guide member 72 side is provided with a driven roller that forms the other while being held by a leaf spring (not shown). .
The first guide member 70 is the wall surface of the transport path switching unit 15 or is fixed to the transport path switching unit 15, and the second guide member 72 is provided so that the paper transport path 69 can be opened. The second guide member 72 includes a main guide member 72A connected to the fixing device 14 via a shaft 73 so as to be rotatable in the vertical direction, and a shaft 74 at a downstream end portion in the transport direction of the main guide member 72A. Thus, it is configured to be divided into sub guide members 72B that are pivotably connected in the vertical direction.

As shown in FIG. 7, only the downstream side of the sheet conveyance path 69 can be opened by rotating the sub guide member 72B upward.
The sub guide member 72 </ b> B is provided with a lock unit that locks the conveyance path switching unit 15. The locking means includes an engaging claw 75 urged so as to be always engaged with an engaging portion (not shown) on the conveyance path switching portion 15 side, and an opening / closing lever 76 provided on the rotation shaft of the engaging claw 75. Have. When the opening / closing lever 76 is rotated in a direction away from the conveyance path switching unit 15, the lock between the sub guide member 72 </ b> B and the conveyance path switching unit 15 is released, and the sub guide member 72 </ b> B is rotatable about the shaft 74. Become.

When the lock of the sub guide member 72B is not released, the state of forming the paper transport path 69 is maintained.
For example, if the engaging claws 75 described above are provided at both ends of one shaft penetrating in the width direction of the sub guide member 72B, and the opening / closing lever 76 is attached to the central portion of the penetrating shaft, the opening / closing lever 76 is operated to close the shaft. Can be released, and the sub guide member 72B can be opened as it is while the open / close lever 76 is held. That is, the opening / closing lever 76 also has a function as an operation lever (grip) when opening the sub guide member 72B.

The shaft 74, which is the pivot point of the sub guide member 72B, also serves as a locking means for the transport path switching unit 15 of the main guide member 72A. As shown in FIG. 8, the shaft 74 is biased in the axial direction by a spring 92, and its end is fitted in the hole of the side plate 17 </ b> A of the transport unit 17. The main guide member 72A cannot be opened in the fitted state.
As shown in FIG. 8A, a cam 90 having an inclined surface is integrally provided on the sub guide member 72B, and a cam 91 having an inclined surface is integrally provided on the shaft 74 correspondingly. ing. When the sub guide member 72B is rotated in the opening direction and opened by a certain angle or more, as shown in FIG. 8B, the cam 90 presses the cam 91 in the axial direction, so that the shaft 74 is disengaged from the hole of the side plate 17A. The main guide member 72A can be rotated about the shaft 73 on the fixing device 14 side as a fulcrum.

The operation procedure when a paper jam occurs is described. When a paper jam occurs, the location of the paper jam is displayed on the operation panel 1B of the copying machine main body 18. When the occurrence location is the paper conveyance path 69 between the fixing portion and the paper discharge port, the conveyance unit 17 is pulled out from the copying machine body 18 to the front.
Thereby, for example, the fixing device 14 connected to the second guide member 72 is exposed. When the open / close lever 76 provided on the sub guide member 72B is operated, the engaging claw 75 of the sub guide member 72B in the closed state is released and the sub guide member 72B can be opened, but can be opened so far. Only the sub guide member 72B can be formed.
When the sub guide member 72B is rotated and opened at a certain angle or more, the shaft 74 that functions as the positioning of the sub guide member 72B and the lock function of the main guide member 72A is drawn inward to release the lock. When the entire second guide member 72 is rotated, a stopper (not shown) is provided so that the opening angle (rotation angle) of the main guide member 72A is limited by θ2, as shown in FIG. It cannot be moved. The opening angle of the sub guide member 72B with respect to the main guide member 72A is also limited by θ1.

When the entire second guide member 72 is opened, a paper jam detection release switch (not shown) provided on the transport unit 17 side operates, and the jammed paper is pulled out and processed, and the opened second guide member 72 is removed. When the original closed state is restored and the transport unit 17 is also set in the copying machine main body 18 as it is, the paper jam display on the operation panel 1B is canceled.
The fixing device 14 includes a heating roller (fixing roller) 67 having a heat source, and a pressure roller 68 in pressure contact with the heating roller 67.
In FIG. 9, reference numeral 77 denotes a conveyance guide member as a part of the first guide member 70, reference numeral 78 denotes a protection member described later, and reference numeral 79 denotes a stay member described later.

In an image forming apparatus using an electrophotographic process, including the image forming apparatus in this embodiment, a toner image formed on a photoconductor as described above is transferred onto a transfer sheet and then added to a heating roller. Fixing is performed by a fixing device including a pressure roller. The fixing device performs fixing by applying heat and pressure when the transfer paper passes through a pressure contact portion (fixing portion) between the heating roller and the pressure roller. The transfer paper that has been fixed at the press contact portion is easily carried in the rotation direction together with the heating roller because the toner forming surface is in close contact with the heating roller surface, but is separated to the heating roller surface corresponding to the downstream side of the press contact portion. By pressing the tip of the claw, the leading edge of the transfer paper is forcibly separated and conveyed in the paper discharge direction.
Further, a plurality of separation claws of the fixing device need to be arranged in accordance with the transfer paper of each size corresponding to the width of the transfer paper to be handled. It is desirable that the separation claw be configured to be separated from the surface of the fixing roller because maintenance, paper jam processing, and the like are necessary.

In the present embodiment, as described above, the rotation fulcrum (shaft 73) of the second guide member 72 is provided in the casing of the fixing device 14 constituted by the heating roller 67, the pressure roller 68, and the like.
As shown in FIG. 10, the stay member 79 is also rotatably provided with a shaft 73 as a fulcrum, and the stay member 79 is provided with a separation claw 81 as a fixing separation member. The stay member 79 is connected to the main guide member 72 </ b> A by a bolt 86, and rotates in synchronization with the entire opening operation of the second guide member 72.
The separation claw 81 is rotatably supported by fitting a shaft into a hole portion of a support portion 80 formed to protrude from the lower surface of the stay member 79. The separation claw 81 has a sharp tip shape, and the tip abuts against the outer peripheral surface of the heating roller 67 by the biasing force of a spring (not shown) disposed between the end 81 a opposite to the tip side and the stay member 79 body. ing.
When it is assumed that there is no heating roller 67, the tip of the separation claw 81 is urged so as to bite into the heating roller 67 as shown by a two-dot chain line. The separation claw 81 has a configuration in which a plurality of claws are arranged in the width direction of the paper.

The protection member 78 is provided on the back side of the separation claw 81 (on the side opposite to the heating roller 67), and is provided rotatably like the stay member 79 with the shaft 73 as a fulcrum. The lower end surface of the protection member 78 constitutes a part of a guide member constituting the paper transport path 69, and the paper that has passed through the fixing device 14 and separated by the separation claw 81 is passed to the paper transport path 69. Guided. The protection member 78 can be regarded as a part of the second guide member 72, strictly, a divided body of the main guide member 72A.
The protection member 78 is made of synthetic resin. Since the protection member 78 is heated by the heat of the heating roller 67, a material having low heat conductivity and excellent heat resistance is desirable so as not to cause burns or the like even if an operator touches it during jam processing. From this viewpoint, for example, a polycarbonate resin or the like can be employed.
The protection member 78 is connected to the stay member 79. The stay member 79 is formed with an arcuate guide groove 82 along a rotation curve, and a convex portion 85 formed integrally with the protection member 78 is engaged with the guide groove 82.

In a state in which the separation claw 81 is in contact with the heating roller 67, the convex portion 85 is positioned above the guide groove 82, and the second guide member 72 is rotated upward, and the stay member 79 is accordingly moved. Even when the protective member 78 rotates, the protective member 78 does not rotate at first, and starts rotating after the convex portion 85 contacts the lower end of the guide groove 82.
The length of the guide groove 82 is set so that the rotation of the protection member 78 starts after the separation claw 81 is accommodated in the protection member 78 so as to be completely covered. Therefore, the operator can be completely prevented from accidentally contacting the separation claw 81.
Inside the protective member 78, a housing portion 83 is formed so that the rear end portion 81b of the separation claw 81 comes into contact therewith and is completely housed, as indicated by hatching. Instead of the connection by the guide groove 82 and the convex portion 85, the protection member 78 may start rotating after the rear end portion 81 b of the separation claw 81 abuts on the housing portion 83.

A state where the main guide member 72A is opened at an angle θ2 is indicated by a two-dot chain line. The separation claw 81 is completely accommodated in the protection member 78, and the separation claw 81 and the protection member 78 are largely separated from the heating roller 67 and the paper conveyance path 69, and a jam processing space is secured. The tip of the separation claw 81 faces the bottom surface of the protective member 78 and is not exposed to the storage opening, so that contact with the operator is completely cut off.
A convex portion 84 is formed at the lower end of the main guide member 72 </ b> A, and the convex portion 84 abuts on the conveyance guide member 77, whereby the separation claw 81 is positioned and the interval of the paper conveyance path 69 is maintained.

When the main guide member 72 </ b> A is opened, the stay member 79 is also opened along with this operation, and the separation claw 81 attached to the stay member 79 is separated from the outer peripheral surface of the heating roller 67. At the same time, the protection member 78 whose movement range is restricted by the stay member 79 does not move unless the stay member 79 is opened by a certain angle or more.
The angle is an angle at which the separation claw 81 that is separated from the outer peripheral surface of the heating roller 67 is completely stored inside the protection member 78. When the stay member 79 is opened beyond this angle, the protection member 78 is opened. Is released with the separation claw 81 covered.
After the main guide member 72A is opened to the limit angle θ2, paper jam processing (jam processing) is performed. At this time, the sheet conveyance path 69 from the fixing portion to the sheet discharge port is exposed, but the separation claw 81 is separated from the outer peripheral surface of the heating roller 67 and is covered with the protective member 78.
After the paper jam processing, when the main guide member 72A is returned to a predetermined position, the stay member 79 and the protection member 78 are also returned to their original positions. Further, the separation claw 81 also comes out of the protection member 78 and returns to a position where it comes into contact with the outer peripheral surface of the heating roller 67 and is urged by the spring with a constant pressing force.

1 is a perspective view of a digital copying machine as an image forming apparatus in an embodiment. 2 is a schematic front view of the digital copying machine. FIG. It is a principal part perspective view of the state where a conveyance unit was pulled out. It is a general | schematic front view of a conveyance unit. It is a schematic diagram which shows the electrical connection structure by the drawer function of a conveyance unit, and a harness. FIG. 6 is a schematic front view showing a conveyance path from a fixing part to a discharge part in the conveyance unit. It is a general | schematic front view of the state which rotated and opened some guide members in the conveyance path | route. It is a general | schematic side view which shows the movable structure of the fulcrum shaft of a guide member. It is a general | schematic front view which shows releasing operation | movement of a guide member. It is a general | schematic enlarged front view which shows the movement of a stay member and a protection member accompanying the releasing operation of a guide member.

Explanation of symbols

67 Heating roller as a fixing member 72A Main guide member as a guide member 72B Sub guide member as a guide member 73 Shaft as a rotation fulcrum 78 Protection member 79 Stay member 81 Separation claw as a fixing separation member S As sheet-like recording medium Paper

Claims (7)

  A fixing separation member for separating a sheet-like recording medium from a surface of a fixing member of a fixing device for fixing an image, and the fixing separation member on a stay member which is rotatably provided with a fixed shaft as a fulcrum When the stay member is rotated, the fixing separation member is provided so as to be able to contact with and separate from the fixing member. The stay member is rotated to separate the fixing separation member from the fixing member. An image forming apparatus comprising: a protective member for housing the fixing separation member so as to cover the fixing separation member. The image forming apparatus according to claim 1.
The protective member constitutes a part of the transport path from the fixing part to the discharge part, and the protective member is also displaced to a position for opening the transport path with the operation of separating the fixing separation member from the fixing member. An image forming apparatus. The image forming apparatus according to claim 2.
An image forming apparatus, wherein the protection member is provided so as to be rotatable and displaceable, and shares a rotation fulcrum of the stay member. The image forming apparatus according to claim 2 or 3,
The rotation position of the stay member for separating the fixing separation member from the fixing member is limited, and the protective member starts to be displaced after the fixing separation member is completely accommodated. apparatus. The image forming apparatus according to any one of claims 1 to 4, wherein:
The conveyance path from the fixing part to the discharge part is composed of guide members facing the front and back surfaces of the sheet-like recording medium, and one of these guide members is rotatably provided so as to open the conveyance path. The image forming apparatus is characterized in that the stay member rotates as the one guide member rotates. The image forming apparatus according to claim 5.
An image forming apparatus, wherein the stay member is fixed to the one guide member. The image forming apparatus according to any one of claims 1 to 6,
An image forming apparatus, wherein the protective member is formed of a synthetic resin.

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