JP2005089178A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a fixing unit to be pulled out in a conveying direction, and to quickly and easily eliminate paper jam in the fixing unit and on its downstream side. <P>SOLUTION: A paper conveying unit 40 is configured changeably in attitude between a closing attitude and an opening attitude separated from the outside surface on the downstream side of the paper conveying unit 40 by opening or closing by turning about a support shaft 104 disposed in an apparatus body 11. A conveying surface on the fixing unit 30 side is formed on the outside surface on the downstream side of the fixing unit 30. The paper conveying unit 40 is provided with the conveying surface on the fixing unit side forming an upside conveying passage 412 facing the conveying surface on the fixing unit 30 side in a set state to the closing attitude. The inside of the apparatus body 11 is provided with a guide rail 301 for supporting the fixing unit 30 extractably in the paper conveying direction from the inside of the apparatus body 11 while the paper conveying unit 40 is set in the opening attitude. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is disposed in the apparatus main body so as to face a fixing unit that performs a fixing process on a transfer image transferred to a sheet by an image transfer unit in the apparatus main body such as a copying machine, a facsimile machine, and various printers. The present invention relates to an image forming apparatus including a paper transport unit that can be opened and closed.

  The image forming apparatus includes a document image reading unit that optically reads a document image, and an image that transfers a toner image formed on the peripheral surface of the photosensitive drum on a sheet based on image data read by the document image reading unit. A transfer unit and a fixing unit that performs a fixing process on a transfer image of a sheet transferred by the image transfer unit are included in a box-shaped device body.

  The paper on which the transfer image is formed is sequentially supplied to the image transfer unit via a predetermined conveyance path from a paper storage unit provided in the device main body or a manual paper supply unit provided at an appropriate position on the side surface of the device main body. After the image is transferred by the image transfer unit, the image is transferred by a heat treatment by passing between a fixing roller heated in the fixing unit of the fixing unit and a receiving roller disposed opposite to the fixing roller. The image is fixed. The paper on which the fixing process has been completed passes through a predetermined conveyance path and is discharged onto a paper discharge tray provided at an appropriate position of the apparatus main body.

  By the way, the paper supplied from the paper storage unit or the manual paper feeding unit may be jammed while moving on the conveyance path or during the transfer process or the fixing process. When such a paper jam occurs, the device is temporarily turned on. It is supposed to be stopped. Then, when the driving of the device is stopped, the predetermined cover provided on the device main body is opened or the device main body is divided, and the jammed paper is removed while the inside of the device main body is exposed. .

  Paper jams occur at various points in the conveyance path, but often occur in a conveyance path provided on the downstream side of the fixing unit. This is because the sheet is heated and stretched by the fixing roller with one side heated by the fixing unit, so that the sheet is bent toward the other side, and the leading end in the transport direction projects against the wall surface of the transport path. It is because it becomes easy to start.

  For this reason, the fixing unit is pulled out from the device main body and exposed to the outside as a whole in order to facilitate the paper jam clearing process in the fixing unit, or the fixing unit in the device main body. The side wall corresponding to the downstream side is generally a cover body that can be freely opened and closed, and the cover body is generally opened.

  Conventionally, in the case where the cover body as described above is provided, a sheet for discharging paper between a surface of the cover body facing the fixing unit and a predetermined guide member provided between the opposing surface and the fixing unit. Since the conveyance path is generally formed, even if the cover body is opened, the guide member becomes an obstacle and the fixing unit cannot be pulled out toward the cover body. It was pulled out to the front side of the device main body (direction perpendicular to the paper transport direction).

  However, the transport path is inherently suitable for directing the paper in the transport direction and is structured so that the paper cannot be smoothly moved in the direction perpendicular to the transport direction. If the fixing unit is pulled out in the direction perpendicular to the paper transport direction, the jammed paper breaks and a secondary paper jam occurs.

Thus, for example, Patent Document 1 describes a cover body in which a conveyance path is formed. When the transport path is formed inside the cover body, the guide member provided on the apparatus main body side is unnecessary, so that there is no disturbing guide member with the cover body open, so that the fixing unit is moved in the paper transport direction. It becomes possible to pull it out. Incidentally, in the image forming apparatus described in Patent Document 1, the technical idea of extracting the fixing unit from the apparatus main body in the sheet transport direction is not disclosed.
JP-A-11-288140

  However, in the case of the document described in Patent Document 1, when a paper jam occurs in the fixing unit, the jammed paper can be easily removed to eliminate the paper jam, but the conveyance path is provided inside the cover body. Therefore, when a paper jam occurs in the transport path, the cover body itself must be disassembled and the paper must be taken out, and eventually the downstream side of the fixing unit where the paper jam is most likely to occur. There is a problem in that it cannot contribute to facilitating the paper jam clearing operation in the transport path.

  The present invention has been made in view of the situation as described above. The fixing unit can be pulled out in the paper transport direction, and paper jams on the fixing unit and its downstream side can be quickly and easily eliminated. An object of the present invention is to provide an image forming apparatus provided with an openable and closable paper transport unit.

  According to a first aspect of the present invention, in the image forming apparatus for discharging the paper through an image forming unit for transferring an image and a fixing unit for fixing the transferred image, provided in a paper transport path in the apparatus main body, the paper transport A downstream conveyance path portion formed on one side wall of the apparatus main body, and a downstream conveyance path section that is a part of the path and immediately downstream in the sheet conveyance direction of the fixing section; and the downstream conveyance path section can be opened and closed with respect to the apparatus main body. And an open / close mechanism that is capable of reciprocating in the direction of the one side wall so as to expose the fixing unit from the apparatus main body.

  According to the present invention, since the sheet conveyance path is formed between the conveyance path on the downstream conveyance path side and the conveyance surface on the fixing unit side with the downstream conveyance path section closed, the fixing unit fixes the transfer image. The processed paper is discharged to a predetermined position through this paper transport path.

  In addition, the downstream conveyance path that has been closed to perform operations such as clearing paper jams and performing maintenance work on the fixing unit, etc., is rotated around the support shaft and deformed to the open position, thereby supporting it in the device body. The fixing unit mounted through the member is in a state where the outer surface on the downstream side is exposed to the outside, so that the fixing unit can be pulled out through the support member, thereby causing a paper jam. Can be easily performed, maintenance work for the fixing unit, and the like.

  The slide mechanism supports the fixing unit so that it can be pulled out from the inside of the apparatus toward the sheet conveyance direction with the downstream conveyance path portion opened. Compared to the case where the paper is pulled out in the direction perpendicular to the transport direction, for example, when the fixing unit is pulled out, the jammed paper does not move in a direction different from the normal direction, and is accompanied by the fixing unit in the transport direction. Moving.

  Therefore, when the fixing unit is pulled out in a direction perpendicular to the sheet conveyance direction, there is a problem that the sheet breaks due to unscheduled contact with various members for conveyance such as a conveyance roller. In the present invention, such inconvenience does not occur, and the jammed paper is removed smoothly, so that the subsequent maintenance work can be performed smoothly.

  According to a second aspect of the present invention, in the first aspect of the present invention, a protective projection is formed at an appropriate position on the inner surface of the one side wall.

  According to the present invention, when the fixing unit is pulled out from the apparatus main body in a state where the downstream conveying path is half-opened, the fixing unit interferes with the protecting projection on the cover body and presses the protecting projection. The part rotates around the support shaft and is completely opened, and the fixing unit pulled out thereby comes into contact with the conveyance unit side conveyance surface, or the operator's hand that pulls out the fixing unit operates the conveyance surface on the conveyance unit side. Contact with the various projections (for example, the tip of the sheet discharge direction switching member) is avoided.

  According to a third aspect of the present invention, in the first or second aspect of the invention, a sheet conveyance path is formed between the downstream conveyance path section and the fixing section in a state where the downstream conveyance path section is closed. It is characterized by this.

  According to the present invention, when the paper jam occurs, the downstream conveyance path portion is opened, and the paper conveyance path is broken into two and the jammed paper is exposed to the outside. This eliminates paper jams and makes it extremely easy.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the downstream transport path portion is parallel to the one side wall in a state in which the downstream transport path portion is closed. A direction switching member that performs direction switching between a direction and a direction intersecting with the direction is provided.

  According to the present invention, by switching the discharge direction switching member, the discharge destination of the paper discharged from the fixing unit to the paper transport path is set between the predetermined position of the device main body and the outside of the device main body. Can be selected arbitrarily.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the downstream conveyance path portion is used for conveying a sheet to a predetermined duplex unit when performing duplex transfer on the sheet. A recess is provided in which a transport unit to be mounted can be mounted.

  According to the present invention, the image forming apparatus can perform so-called double-sided printing by mounting a transport unit used for transporting paper to a predetermined duplex unit when performing double-sided transfer in the recess of the downstream transport path. Is converted to the correct mode. In order to execute double-sided printing, it is premised that a reverse conveyance unit having a structure capable of supporting double-sided printing is provided in advance in the apparatus main body.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the device main body is provided with a mechanism for reversing the paper derived from the transport unit.

  According to the present invention, the conveyance unit is mounted in the concave portion of the downstream conveyance path portion, so that the image forming apparatus can perform so-called double-sided copying.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the fixing unit prevents interference with a facing surface of the downstream conveyance path unit in a state of being pulled out from the apparatus main body. A protruding support member is provided.

  According to the present invention, the fixing unit is prevented from interfering with the facing surface of the downstream conveying path portion by the protruding member in the state of being pulled out from the apparatus main body. Generation | occurrence | production of the problem which collides with the various members provided and damages these members can be prevented effectively.

  The invention according to claim 8 is the invention according to claim 7, wherein the projecting member is pivotally supported on a lower side portion of the fixing portion so as to be rotatable around a predetermined axis, and the fixing portion is By being pushed into the apparatus main body, it is rotated in one direction around the axis due to interference with the apparatus main body to be set in the stowed posture, while the interference caused by the fixing unit being pulled out from the apparatus main body is eliminated. Thus, the posture is set to a drooping posture that is pivoted in the other direction around the axis and hung from the axis.

  According to the present invention, when the fixing unit is pushed into the apparatus main body, the projecting support member interferes with the apparatus main body and rotates in one direction around a predetermined axis, thereby setting the attitude of the projecting support member to the storage posture. On the other hand, by pulling out the fixing unit from the main body of the apparatus, the interference of the projecting member is eliminated, so that the projecting member rotates in the other direction around the axis and is set in a suspended position suspended from the shaft. Is done.

  In this way, by supporting the projecting member so as to be rotatable about the axis provided in the fixing unit, the projecting member can be configured not to interfere with the pushing operation of the fixing unit into the apparatus main body. In addition, by pulling out the fixing unit from the apparatus main body, the fixing unit can be hung downward from the fixing unit, which can contribute to simplification of a collision avoidance structure for the downstream conveying path unit of the fixing unit.

  According to the image forming apparatus of the present invention, the sheet disposed in the apparatus body facing the downstream outer surface of the fixing unit that fixes the transferred image transferred to the sheet by the image transfer unit in the apparatus body. The transport unit rotates around a support shaft provided in the device main body orthogonal to the paper transport direction and opens and closes to close the closed posture facing the downstream outer surface of the fixing unit, and an opening spaced from the downstream outer surface. The posture can be changed between the posture and the fixing unit side transport surface is formed on the downstream outer surface of the fixing unit, while the paper transport unit is fixed in the closed posture. A transport unit side transport surface that forms a paper transport path opposite to the unit side transport surface is formed, and a support member that supports the fixing unit is provided in the apparatus main body, and the support member is opened by the paper transport unit. Since the fixing unit is configured to be supported in such a manner that it can be pulled out from the inside of the apparatus body in the paper conveyance direction, the conveyance unit is set in the closed posture. A sheet conveyance path is formed between the side conveyance surface and the fixing unit side conveyance surface, and the sheet on which the transfer image has been fixed by the fixing unit is discharged to a predetermined position via the sheet conveyance path. can do.

  In addition, by operating the paper transport unit, which has been set to the closed position to perform paper jam clearing operations and maintenance operations for the fixing unit, to rotate around the support shaft, the posture is changed to the open position. Since the fixing unit mounted in the inside is exposed to the outside on the downstream side, the fixing unit can be pulled out to the outside through the supporting member. Accordingly, it is possible to easily perform a paper jam clearing operation, a fixing unit maintenance operation, and the like.

  The support member is configured to support the fixing unit so that the fixing unit can be pulled out from the apparatus main body toward the sheet conveying direction in a state where the sheet conveying unit is set to the open posture. The jammed paper does not move in a direction different from the normal direction, and it moves along with the fixing unit in the transport direction, so that the jammed paper can be removed smoothly. Maintenance work can be performed smoothly.

  FIG. 1 and FIG. 2 are side sectional views illustrating an embodiment of an image forming apparatus 10 including an openable / closable paper transport unit 40 according to the present invention. FIG. FIG. 2 shows a state in which the posture is set to the posture, and FIG. 2 shows a state in which the paper transport unit 40 is set in the open posture and the fixing unit 30 is pulled out.

  As shown in FIG. 1, the image forming apparatus 10 includes an apparatus main body 11, an image forming unit (image forming unit) 12, a paper feeding mechanism 18 that feeds paper to the image forming unit 12, and an image. A fixing unit (fixing unit) 30 for fixing an image on a sheet sent from the forming unit 12 is built in the device main body 11 and is provided in the device main body 11 so as to be openable and closable so as to face the fixing unit 30. In addition, a basic configuration having a sheet transport unit (downstream transport path) 40 is provided.

  The image forming unit 12 forms a toner image on a sheet fed from the sheet feeding mechanism 18, and in this embodiment, the image forming unit 12 is sequentially arranged from the upstream side (the right side of the paper surface in FIG. 1) to the downstream side. The magenta unit 12M, the cyan unit 12C, the yellow unit 12Y, and the black unit 12K are provided.

  Each unit 12M, 12C, 12Y, 12K is provided with a developing device 13 and a photosensitive drum 14, respectively. Each photoconductor drum 14 is supplied with toner from the corresponding developing device 13 and rotates in the clockwise direction in FIG.

  A charging unit 15 is provided at a position on the upper left side in FIG. 1 of each photosensitive drum 14, and an exposure unit 16 is provided at a position on the upper right side in FIG. Each photosensitive drum 14 is uniformly charged at its peripheral surface by the charging unit 15, and LED light based on image data input from a reading device (not shown) is charged from each exposure unit 16 to the photosensitive member after charging. By irradiating the peripheral surface of the drum 14, an electrostatic latent image is formed on the peripheral surface of each photosensitive drum 14. By supplying toner from the toner container of the developing device 13 to the electrostatic latent image, a toner image is formed on the peripheral surface of the photosensitive drum 14.

  An in-apparatus transport unit 20 is provided below each photoconductor drum 14. The in-device transport unit 20 includes a base 21 and a transport belt 22 that is supported by the base 21 and circulates counterclockwise in FIG. The conveyor belt 22 is arranged between a driving roller 23 provided at the lower left end of the base 21 in FIG. 1, a driven roller 24 provided at the right end, and between the driving roller 23 and the driven roller 24. It is wound around a predetermined number of rolling rollers 25 provided, and rotates around the counterclockwise direction by the rotational drive of the driving roller 23.

  Four of the rolling rollers 25 facing the photosensitive drums 14 are pressed against the respective photosensitive drums 14 via the conveying belts 22, and thereby to the paper conveyed by the conveying belts 22. The transfer from the photosensitive drum 14 is reliably performed. Further, a cleaning mechanism 17 for removing residual toner on the peripheral surface of the photosensitive drum 14 and cleaning it is provided at a lower left position in FIG. 1 of each photosensitive drum 14. The peripheral surface of the photosensitive drum 14 cleaned by the cleaning mechanism 17 goes to the charging unit 15 for a new charging process.

  The sheet fed from the sheet feeding mechanism 18 as indicated by an arrow is guided along the circumference of the transport belt 22 and is fed between the photosensitive drums 14 and the rolling rollers 25, and the units 12M, 12C, The transfer processing is sequentially performed at 12Y and 12K, and after the transfer processing by the black unit 12K is completed, the transfer processing is introduced into the fixing unit 30. The paper introduced into the fixing unit 30 is subjected to a fixing process by heating the transfer image, and the paper that has been subjected to the fixing process is a paper discharge tray provided on the top of the apparatus main body 11 via the paper transport unit 40. 19 is discharged.

  The paper feed mechanism 18 is usually a paper feed cassette in which a plurality of sheets are stacked and stored. However, when performing so-called double-sided printing in which transfer processing is performed on the front and back surfaces of paper, the paper feed mechanism 18 is replaced with a paper feed cassette. A known duplex printing unit is mounted. This double-sided printing unit is used by being placed in a paper feed cassette, and has a switchback unit that reverses the front side of the paper on which one side is printed, and the paper that has been turned upside down by this switchback unit. The paper is fed again. Therefore, when performing double-sided printing, after transfer processing and fixing processing are performed on one side of the paper fed out from the cassette unit, the paper is introduced into the double-sided printing unit via the transport unit 50 described later. In the double-sided printing unit, first, the front and back sides of the sheet are reversed by the switchback unit, and then fed again to the image forming unit 12. After the transfer process is performed on the back side, the sheet discharge tray 19 is passed through the fixing unit 30. The paper is ejected to etc.

  3 to 5 are partial enlarged cross-sectional views of the fixing unit 30 and the paper transport unit 40 of the image forming apparatus 10 shown in FIG. 1, and FIG. 3 shows a state in which the paper transport unit 40 is set to the closed posture. 4 shows a state where the fixing unit 30 is being pulled out from the apparatus main body 11 while the posture of the paper transport unit 40 is changed from the closed posture to the open posture, and FIG. 5 shows a state where the paper transport unit 40 is set to the open posture. In addition, a state where the fixing unit 30 is pulled out from the apparatus main body 11 is shown.

  6 and 7 are partial perspective views showing the sheet conveyance unit 40 side of the fixing unit 30. FIG. 6 shows the sheet conveyance unit 40 set to the open posture, and the fixing unit 30 is the device main body 11. FIG. 7 shows a state before the fixing unit 30 is pulled out from the apparatus main body 11.

  8 and 9 are perspective views showing the paper transport unit 40. FIG. 8 shows a state immediately before the transport unit 50 is mounted, and FIG. 9 shows a state where the transport unit 50 is mounted. ing.

  First, as shown in FIG. 3, the fixing unit 30 includes a housing 31 having a box shape that is long in the width direction (a direction orthogonal to the paper surface of FIG. 3). The fixing roller 32 includes, for example, a heating roller 33 that is overheated by an energized heating element, a pressure roller 34 that is disposed opposite to the lower portion of the heating roller 33, and whose peripheral surface is in contact with the peripheral surface of the heating roller 33. It is made up of. In the present embodiment, the heating roller 33 is a driving roller that rotates around an axis by driving of a driving motor (not shown).

  On the other hand, an inlet 311 for introducing paper is opened on the upstream side wall (right side in FIG. 3) of the housing 31, and an outlet 312 for leading paper is provided on the downstream side wall. It is open. The sheet introduced into the housing 31 through the introduction port 311 is guided by the driving rotation around the axis of the heating roller 33 and is heated by heat transfer while passing between the heating roller 33 and the pressure roller 34. As a result, the transfer image on the paper is fixed by the previous image forming unit 12 (FIG. 1) and led out toward the paper transport unit 40 through the outlet 312. Yes.

  The fixing unit 30 has a pair of slide rods 35 (see FIG. 7) in the width direction provided on the bottom surface so as to extend in the front-rear direction (left-right direction in FIG. 3). On the pair of inner wall surfaces, a guide rail (support member) 301 having a U-shape in a cross-sectional view for supporting the slide rods 35 so as to be movable back and forth is laid so as to extend in the front-rear direction. Then, when the pair of slide rods 35 are fitted into the corresponding guide rails 301, the fixing unit 30 is placed in the storage position stored in the device main body 11 shown in FIG. 3 and from the device main body 11 shown in FIG. The position can be changed between the withdrawn position and the withdrawn position.

  In addition, a gripping member 36 (see FIG. 6) is provided at a corner on the downstream side (left side in FIG. 3) of the housing 31 so as to project outward from the center position in the width direction. The gripping member 36 is used for gripping the fixing unit 30 by hand when the fixing unit 30 is pulled out from the apparatus main body 11. When the fixing unit 30 is pulled out from the apparatus main body 11, a later-described protective protruding piece of the paper transport unit 40 is used. It is also possible to play the role of prompting the full opening of the half-opening paper transport unit 40 by interfering with the (protective protrusion) 45 (see FIG. 4).

  The sheet transport unit 40 is mounted on the apparatus main body 11 so that the rear surface opening 101 of the fixing unit 30 opened on the downstream side wall of the apparatus main body 11 is blocked and the inner surface side can face the downstream wall of the fixing unit 30. .

  The sheet transport unit 40 includes a transport unit main body 41, a lower paper discharge direction switching member 42 provided on the transport unit main body 41 so as to face the outlet 312 of the fixing unit 30, and a lower paper discharge direction switching member 42. Mounting for mounting the upper discharge direction switching member 43 provided in the transport unit main body 41 at a higher position and the transport unit 50 provided in the transport unit main body 41 at a lower position than the lower discharge direction switching member 42 A recess 44 (see FIGS. 8 and 9) is provided. The mounting recess 44 is set at an installation position so that the tip of the gripping member 36 of the fixing unit 30 is slightly fitted into the upper position of the mounting recess 44 in a state where the paper transport unit 40 is set to the closed posture.

  Circular supported holes 411 (see FIG. 8) are respectively provided on both side surfaces in the width direction of the lower part of the transport unit body 41 (position slightly below the mounting recess 44), and the device body is provided in the supported holes 411. By inserting support shafts 104 projecting from opposing wall surfaces of 11 in a direction facing each other, the transport unit main body 41 rotates forward and backward around these support shafts to open the rear surface of the device main body 11. The posture can be changed between a closed posture (FIG. 3) in which 101 is closed and an open posture (FIG. 5, FIG. 6, and FIG. 7) that protrudes from the device main body 11 to the outside.

  The transport unit main body 41 is formed with an upper transport path 412 for transporting the paper upward from the lower paper discharge direction switching member 42, and the paper is moved downward from the lower paper discharge direction switching member 42. A lower conveyance path 413 for conveying toward the conveyance unit 50 is formed.

  Further, a protective protrusion 45 (see FIG. 6) that protrudes toward the fixing unit 30 is provided at a position directly above the mounting recess 44 in the transport unit main body 41 and in the center in the width direction. . The protective protruding piece 45 is opposed to the gripping member 36 above the gripping member 36 in a state where the paper transport unit 40 is set to the closed posture. The protective protrusion 45 forms the first embodiment of the collision avoidance structure according to the present invention.

  Further, the transport unit body 41 is provided with a transport roller pair 46 extending in the width direction at the upper end of the upper transport path 412, and the paper that has reached the upstream end of the upper transport path 412 is driven and rotated by the transport roller pair 46. Is sent out upward.

  Further, the transport unit main body 41 is provided with a cover body 48 at a position between the lower paper discharge direction switching member 42 and the upper paper discharge direction switching member 43 on the inner surface side, and the cover body 48 and the transport unit. The upper conveyance path 412 is formed between the main body 41 and an opening 471 (FIG. 6) that is long in the width direction at a position facing the lead-out port 312 of the strain gauge 30 of the cover body 48. A front end of a direction switching fin 421, which will be described later, of the lower sheet discharge direction switching member 42 protrudes from the opening 471 toward the outside.

  In the lower discharge direction switching member 42, the base end side (left side in FIG. 3) of a plurality of direction switching fins 421 (see FIG. 6) having a substantially triangular shape in a side view penetrates the direction switching shaft 422. It is formed by being fixed. The lower sheet discharge direction switching member 42 is supported by penetrating both end portions of the direction switching shaft 422 into the corresponding side wall of the transport unit main body 41, and the shaft of the direction switching fin 421 driven by a driving means (not shown) such as a solenoid. With the forward and reverse rotation around the center, the tip of the direction switching fin 421 tilts slightly forward toward the front (right side in FIG. 3) (shown by a solid line in FIG. 3), and the tip is forward The posture can be changed between a forwardly inclined posture (indicated by a two-dot chain line in FIG. 3) slightly inclined upward.

  The lower sheet discharge direction switching member 42 allows the sheet led out from the outlet 312 to pass through the upper conveyance path 412 through the opening 471 of the cover body 48 in a state where the direction switching fin 421 is set to the first lowering posture. Setting and setting of the installation position so that the sheet led out from the outlet 312 is guided toward the lower conveyance path 413 in a state where the direction switching fin 421 is set in the forwardly rising posture. Has been made.

  In the upper discharge direction switching member 43, the base end side (upper side in FIG. 3) of a plurality of direction switching fins 431 (see FIG. 6) having a substantially triangular shape in a side view is a cross shaft 432 for direction switching. It is formed by being penetrated integrally with. The upper sheet discharge direction switching member 43 is supported by penetrating both ends of the cross shaft 432 through corresponding side walls of the transport unit main body 41, and driving the driving means (not shown) such as a solenoid. A hanging posture (indicated by a solid line in FIG. 3) where the tip hangs down by forward / reverse rotation around 432 and abuts the transport unit main body 41, and a plurality of fixings in which the tip is formed on the upper rear surface of the fixing unit 30 The posture can be changed between an inclined posture (indicated by a two-dot chain line in FIG. 3) fitted between the fins 302.

  The upper sheet discharge direction switching member 43 fixes the sheet led out from the upper conveyance path 412 via the conveyance roller pair 46 to the direction switching fin 431 in a state where the direction switching fin 431 is set in the hanging posture. The direction switching fins 431 are set in an inclined posture while being guided toward the paper discharge tray 19 via a gap between the fins 302 and a conveyance path 102 formed between predetermined frames in the apparatus main body 11. In this state, the shape setting and the setting position are set so that the sheet led out through the conveying roller pair 46 is guided to the outside through the paper discharge port 414.

  A discharge roller 47 for discharging the paper that has reached the discharge port 414 is provided at a position below the discharge port 414 in the transport unit main body 41. Paper discharge toward the outside of the paper is smoothly performed in a state where the paper direction switching member 43 is set to the inclined posture.

  Further, the transport unit main body 41 is provided with a transport roller 49 at a position above the upper paper discharge direction switching member 43, and a predetermined roller in the apparatus main body 11 has a transport roller 103 facing the transport roller 49. And a pair of conveying rollers for feeding the sheet toward the sheet discharge tray 19 by these conveying rollers 49 and 103 in a state where the sheet conveying unit 40 is set to the closed posture. .

  In the present embodiment, the sheet conveying unit side conveying surface according to the present invention is formed in the portion where the upper sheet discharge direction switching member 43 is provided, and the rear edge surface of the fixed fin 302 is used in the present invention. The fixing unit side conveying surface is formed, and the sheet conveying path according to the present invention is formed between the sheet conveying unit side conveying surface and the fixing unit side conveying surface.

  The transport unit 50 employs a double-sided printing cassette as the paper feeding mechanism 18, the image forming apparatus 10 itself is set to a so-called double-sided printing mode, and the lower discharge direction switching member 42 is set to a forward-up posture. Sometimes it is adopted. The transport unit 50 includes a transport unit body 51 (see FIG. 8) that has a long box shape in the width direction (a direction orthogonal to the paper surface of FIG. 3), and the transport unit body 41 in the transport unit body 51. A transport unit transport path 52 formed corresponding to the lower transport path 413, and a transport roller pair 53 that feeds the paper to the paper feed mechanism 18 set in the duplex printing mode with the transport unit transport path 52 interposed therebetween. It is configured with.

  A plurality of fixed fins 501 are provided on the surface of the transport unit main body 51 facing the transport unit transport path 52, and the contact area of the sheet is reduced by the presence of the fixed fins 501, thereby the transport unit transport path 52. It is designed to move stably inside.

  The paper feed mechanism 18 (FIG. 1) normally employs a paper feed cassette in which a plurality of sheets are stacked and stored. However, when performing so-called double-sided printing in which transfer processing is performed on the front and back surfaces of paper, A dedicated duplex printing cassette is used instead of the paper cassette.

  The transport unit transport path 52 is provided with an upper inlet side facing a lower opening of the lower transport path 413 of the transport unit main body 41, and a lower outlet side on the paper feed mechanism 18 side of the transport unit main body 51. The sheet provided on the side surface and introduced into the conveyance unit conveyance path 52 by this is discharged toward the sheet feeding mechanism 18.

  As shown in FIGS. 8 and 9, the transport unit 50 is configured to be detachably mounted on the mounting recess 44 of the transport unit body 41, and is shipped as an optional product. Yes.

  The operation of the present invention will be described below with reference to FIGS. 3 to 5 with reference to other drawings as necessary. First, in a state where the paper transport unit 40 is set to the closed posture, as shown in FIG. 3, the cover body 48 of the transport unit main body 41 is substantially in close contact with the downstream end surface of the housing 31 of the fixing unit 30. Thus, the upper side of the upper conveyance path 412 is formed between the upper part of the housing 31 and the conveyance unit main body 41.

  Further, the tip of the direction switching fin 421 of the lower sheet discharge direction switching member 42 enters the outlet port 312 of the housing 31 of the fixing unit 30, and the first descending posture shown by the solid line that guides the sheet to the upper conveyance path 412 side. The posture can be changed between the forward rising posture indicated by the two-dot chain line for guiding the paper to the transport unit 50.

  Further, the direction switching fins 431 of the upper sheet discharge direction switching member 43 are separated from the fixed fins 302 of the housing 31 of the fixing unit 30 by the tips thereof, and thereby the hanging posture for guiding the sheet to the conveying path 102 on the upper side of the apparatus main body 11. Then, the tip of the direction switching fin 431 is fitted between the fixed fins 302, so that the posture can be changed between the inclined posture for guiding the paper to the paper discharge port 414.

  Next, when the paper transport unit 40 is pulled out rearward (leftward in FIG. 3) for paper jam clearing operation or maintenance work, the paper transport unit 40 is inserted into the supported hole 411. As shown in FIG. 6, the fixing unit 30 can be pulled out from the apparatus main body 11 by being rotated in the counterclockwise direction around the supporting shaft 104. In the case of paper jam processing, the upper portion of the upper conveyance path 412 is exposed to the outside with the paper conveyance unit 40 slightly opened, so that the jammed paper can be easily removed.

  However, at this time, when the fixing unit 30 is pulled out from the apparatus main body 11 even though the paper transport unit 40 is in a half-open state, as shown in FIG. 4, the fixing unit 30 is provided at the lower end of the housing 31 of the fixing unit 30. Since the gripping member 36 is in a state of interfering with the protective protrusion 45 of the transport unit main body 41, the further pull-out of the fixing unit 30 is restricted, thereby the direction switching fins 421 protruding from the transport unit main body 4 and the like. Damage due to the protrusion colliding with the housing 31 of the fixing unit 30 is reliably prevented.

  When the paper transport unit 40 is completely opened, the interference of the gripping member 36 with the protective protrusion 45 is eliminated. Therefore, as shown in FIG. 5 and FIG. The fixing unit 30 is pulled out to the maximum, and a predetermined maintenance process is performed on the fixing unit 30 in this state.

  When the paper jam clearing operation in the paper transport unit 40 or the maintenance operation of the fixing unit 30 and the paper transport unit 40 is completed, the fixing unit 30 is pushed into the apparatus main body 11 and the paper transport unit 40 is subsequently closed. The image forming apparatus 10 returns to the initial state where the operation is possible.

  As described above in detail, the image forming apparatus 10 according to the present invention opposes the downstream outer surface of the fixing unit 30 that performs the fixing process on the transfer image transferred to the sheet by the image forming unit 12 in the apparatus main body 11. The apparatus main body 11 is provided with a paper conveyance unit 40, and the paper conveyance unit 40 rotates around a support shaft 104 provided in the apparatus main body 11 perpendicular to the paper conveyance direction to open and close. By doing so, the posture can be changed between a closed posture facing the downstream outer surface of the fixing unit 30 and an open posture separated from the downstream outer surface of the paper transport unit 40.

  On the downstream side outer surface of the fixing unit 30, a conveyance surface on the fixing unit 30 side (surface on which the fixed fins 302 are provided) is formed, while the sheet conveyance unit 40 is set in a closed posture. In this state, a conveyance unit-side conveyance surface (a surface facing the fixed fin 302) is formed to form the upper conveyance path 412 so as to face the conveyance surface on the fixing unit 30 side.

  Further, a guide rail 301 is provided in the device main body 11 to support the fixing unit 30 so that the fixing unit 30 can be pulled out from the device main body 11 in the paper transport direction with the paper transport unit 40 set to the open posture. Yes.

  Accordingly, the paper transport unit 40, which has been set to the closed posture in order to perform the paper jam clearing operation and the fixing unit maintenance work, is rotated around the support shaft 104 to change the posture to the open posture. The fixing unit 30 mounted in the main body 11 via the guide rail 301 is in a state where its downstream outer surface is exposed to the outside, so that the fixing unit 30 is pulled out via the guide rail 301. Accordingly, it is possible to easily perform a paper jam clearing operation, a maintenance operation of the fixing unit 30, and the like.

  The guide rail 301 supports the fixing unit 30 so that the fixing unit 30 can be pulled out from the inside of the apparatus main body 11 toward the sheet conveyance direction in a state where the sheet conveyance unit 40 is set to the open posture. Thus, compared to the case where the fixing unit 30 is pulled out in the direction perpendicular to the sheet conveyance direction, for example, when the fixing unit 30 is pulled out, the jammed sheet does not move in a direction different from the normal direction. When the unit 30 is pulled out in a direction perpendicular to the paper transport direction, the paper is inconveniently broken due to unscheduled contact with various transport members such as a transport roller. In the invention, such inconvenience does not occur, the jammed paper is removed smoothly, and the subsequent maintenance work can be performed smoothly. .

  A conveyance roller 103 that is one roller of a conveyance roller pair that conveys a sheet is mounted on the conveyance surface on the fixing unit 30 side, while the other conveyance roller pair is disposed on the conveyance surface on the sheet conveyance unit 40 side. Therefore, the conveyance roller 49 on the side of the sheet conveyance unit 40 is changed to the fixing unit by closing the sheet conveyance unit 40 set to the open posture and changing the posture to the closed posture. Since the roller pair is completed facing the 30-side transport roller 103, the paper introduced into the upper transport path 412 can be transported more smoothly while being sandwiched between the roller pair.

  Since the cover unit 48 is provided on the transport unit main body 41 of the paper transport unit 40, even if the fixing unit 30 is pulled out from the apparatus main body 11 with the paper transport unit 40 set to the open posture, Since the fixing unit 30 does not come into contact with the inside of the paper transport unit 40 due to the presence of the cover body, various irregularities inside the paper transport unit 40 are protected, and the fixing unit 30 can be pulled out smoothly.

  Further, since the cover body 48 is provided with a protective protrusion 45 that interferes with the fixing unit 30 pulled out from the device main body 11 on the base end side, the fixing unit 30 is attached to the device with the paper transport unit 40 half open. Even when the fixing unit 30 is pulled out from the main body 11, the fixing unit 30 interferes with the protective protrusion 45 and presses the protective protrusion 45, so that the paper transport unit 40 rotates around the support shaft 104 and is completely opened. It is possible to avoid the fixing unit 30 from interfering with various irregularities of the paper transport unit 40.

  Further, an upper discharge direction switching member 43 that switches the discharge direction position so that the sheet is directed to either the discharge tray 19 of the device main body 11 or the outside of the device main body 11 is provided on the transfer surface on the paper transfer unit 40 side. Since it is provided, it is possible to arbitrarily set the paper discharge destination, and the versatility of paper discharge can be improved.

  In addition, since the paper conveyance unit 40 side conveyance surface is provided with a mounting recess 44 in which a paper reversing conveyance unit 50 used for reversing the paper when performing double-sided transfer on the paper can be mounted. The image forming apparatus can be converted into a mode capable of so-called double-sided printing by mounting the conveyance unit 50 for paper reversal when performing double-sided transfer in the mounting recess 44.

  In the above-described embodiment, the cover body 48 is provided on the back side of the transport unit main body 41, and a sheet (a part of the upper transport path 412 is formed between the cover body 48 and the transport unit main body 41). However, instead of this, with the paper transport unit 40 set in the closed position, the surface of the cover body 48 and the downstream end face of the housing 31 of the fixing unit 30 A gap formed therebetween may be a part of the upper conveyance path 412, and the sheet may be sent out toward the paper discharge tray 19 through the gap. By doing so, the paper becomes completely free with respect to the fixing unit 30 and the paper transport unit 40 in a state where the paper transport unit 40 is set to the open posture, so that it is very easy to clear the paper jam.

  FIG. 10 is an explanatory view in a side view showing a second embodiment of a collision avoidance structure for the fixing unit 30 pulled out from the apparatus main body 11 with respect to the paper transport unit 40. FIG. The state in which the position is set, (B) shows the state in which the fixing unit 30 is set to the drawing position. FIG. 11 is a perspective view showing a state in which the fixing unit 30 adopting the collision avoidance structure of the second embodiment is pulled out from the device main body 11 (that is, a normal state where the fixing unit 30 is set at the pulling position).

  As shown in FIG. 10, in the collision avoidance structure of the second embodiment, a pair of width direction (direction perpendicular to the paper surface of FIG. 10) is provided at the lower end portion of the fixing unit 30 at the tip portion 351 of the slide rod 35. Horizontal shafts 352 project outwardly, and projecting support members 37 are pivotally supported around the horizontal shafts 352, respectively. Each projecting support member 37 has an arc edge portion 371 having a tip edge portion formed in an arc shape.

  As shown in FIG. 10A, the protruding support member 37 extends in the horizontal direction in a state where the fixing unit 30 is stored in the storage position and the paper transport unit 40 is set in the closed posture. While the storage posture is set, as shown in FIG. 10B, the horizontal axis is set in a state where the paper transport unit 40 is set to the open posture and the fixing unit 30 is set to the drawing position. The posture is set to a drooping posture that hangs down from 352.

  The distance between the axis of the horizontal shaft 352 of the projecting support member 37 and the edge surface of the arc edge portion 371 is such that the sheet conveyance is in an open posture with the fixing unit 30 pulled out to the pull-out position. The edge surface of the arc edge 371 is set so as to contact the edge surface of the side wall 415 of the unit 40. Further, the horizontal axis 352 is such that the edge surface of the arc edge portion 371 of the projecting support member 37 is a sheet of paper when the fixing unit 30 is pushed into the apparatus main body 11 and the paper transport unit 40 is set to the closed posture. It is provided at a position where it does not interfere with the side wall 415 of the transport unit 40.

  On the other hand, a shelf 105 extending in the front-rear direction is provided in the device main body 11 inside the rear opening 101 and at a position slightly below the front end 351. The shelf portion 105 is provided at a position corresponding to the projecting support member 37, and in a state in which the fixing unit 30 is stored in the storage position, the storage position that extends the projecting support member 37 horizontally by interference with the projecting support member 37. To set the posture.

  Incidentally, in the present embodiment, a cylindrical guided projection 353 projecting outward is provided at the front end of the slide rod 35, and the guided projection 353 is slidably contacted between the pair of guide rails 301. It is pinched in a state. Therefore, the fixing unit 30 is pulled out from the apparatus main body 11 while the guided projection 353 slides between the pair of guide rails 301 by pulling the fixing unit 30 rearward (leftward in FIG. 10) so as to lift it up. It will be.

  According to the collision avoidance structure of the second embodiment, when the fixing unit 30 is pushed into the apparatus main body 11 and the paper transport unit 40 is set to the closed posture, as shown in FIG. In addition, the projecting support member 37 is set in a stowed posture in which the projecting support member 37 extends horizontally rearward from the horizontal shaft 352 on the shelf 105 by interfering with the shelf 105.

  In this state, when the paper transport unit 40 is opened by rotating counterclockwise around the support shaft 104 and then withdrawing from the apparatus main body 11 while lifting the fixing unit 30 with heart, the arc edge 371 is supported by the shelf 105. Thus, the support member 37 is rotated counterclockwise around the horizontal shaft 352 and is set in a hanging posture in which the projecting member 37 hangs downward from the horizontal shaft 352.

  Therefore, even if the fixing unit 30 is rotated counterclockwise around the guided projection 353 by releasing the hand from the fixing unit 30, as shown in FIGS. 37, the edge surface of the circular arc edge portion 371 contacts the edge surface of the edge portion of the side wall 415 of the transport unit main body 41, whereby the fixing unit 30 is supported by the projecting member 37. Inconveniences such as falling down and colliding with various members provided on the back side of the transport unit main body 41 such as the direction switching fins 421 of the lower sheet discharge direction switching member 42 are reliably prevented. The

  On the contrary, when the fixing unit 30 is pushed into the apparatus main body 11, the projecting support member 37 interferes with the rear edge portion of the shelf portion 105, and thereby rotates around the horizontal axis 352 in the clockwise direction. Is pushed to the storage position, and the projecting support member 37 is set to the storage posture placed on the upper surface of the shelf 105 as shown in FIG.

  In the collision avoidance structure of the second embodiment, as described in detail above, the fixing unit 30 has a projecting member 37 that prevents interference with the opposing surface of the paper transport unit 40 in a state of being pulled out from the apparatus main body 11. Accordingly, the fixing unit 30 is prevented from interfering with the opposing surface of the paper transport unit 40 by the projecting member 37 in the state where the fixing unit 30 is pulled out from the apparatus main body 11. It is possible to effectively prevent the occurrence of inconveniences such as colliding with various members (for example, the direction switching fins 421) provided on the opposite surfaces of the members and damaging these members.

  The projecting member 37 is pivotally supported around a horizontal shaft 352 provided at the front end 351 of the slide rod 35 on the lower side of the fixing unit 30, and the fixing unit 30 is supported by the apparatus main body 11. By being pushed in, it is rotated in one direction around the horizontal axis 352 due to interference with the device main body 11 and is set in the storage posture. On the other hand, the fixing unit 30 is pulled out of the device main body 11 to eliminate horizontal interference. Since the posture is set to a drooping posture that pivots in the other direction around the shaft 352 and hangs down from the horizontal shaft 352, when the fixing unit 30 is pushed into the device main body 11, the projecting member 37 is connected to the device main body 11. By interfering and rotating in one direction around the horizontal axis 352, the projecting support member 37 can be set to the retracted posture, while the fixing unit 30 is installed in the device. By withdrawing from the body 11 and eliminates the interference 突支 member 37, thereby 突支 member 37 is posture setting droop position depending from the horizontal axis 352 rotates in the other direction of the horizontal axis 352 around.

  As described above, the projecting member 37 is pivotally supported around the horizontal shaft 352 provided in the fixing unit 30, so that the projecting member 37 has an obstacle to the pushing operation of the fixing unit 30 into the apparatus main body 11. In addition, the fixing unit 30 can be pulled down from the fixing unit 30 by being pulled out from the apparatus main body 11, and the structure for avoiding the collision of the fixing unit 30 with the paper transport unit 40 can be simplified. Can contribute.

1 is a side sectional view illustrating an embodiment of an image forming apparatus including an openable / closable paper transport unit according to the present invention, and illustrates a state in which the paper transport unit is set to a closed posture. FIG. FIG. 4 is an explanatory side sectional view showing an embodiment of an image forming apparatus provided with an openable / closable paper transport unit according to the present invention, in which the paper transport unit is set to an open posture and the fixing unit is pulled out. Each state is shown. FIG. 2 is a partial enlarged cross-sectional view of the fixing unit 30 and the paper transport unit 40 of the image forming apparatus 10 shown in FIG. 1 and shows a state in which the paper transport unit is set to a closed posture. FIG. 2 is a partial enlarged cross-sectional view of a fixing unit and a paper transport unit of the image forming apparatus illustrated in FIG. 1, and shows a state in which the fixing unit is being pulled out from the apparatus body while the paper transport unit is being changed from a closed posture to an open posture. Show. FIG. 2 is a partial enlarged cross-sectional view of a fixing unit and a paper transport unit of the image forming apparatus shown in FIG. 1, showing a state where the paper transport unit is set to an open posture and the fixing unit is pulled out from the apparatus main body. FIG. 6 is a partial perspective view showing the sheet conveying unit side of the fixing unit, showing a state before the sheet conveying unit 40 is set to the open posture and the fixing unit is pulled out from the apparatus main body. FIG. 4 is a partial perspective view showing the sheet conveying unit side of the fixing unit, and shows a state in which the fixing unit is pulled out from the apparatus main body. It is a perspective view which shows a paper conveyance unit, and has shown the state just before a conveyance unit is mounted | worn. FIG. 6 is a perspective view showing a paper transport unit, showing a state where the transport unit is mounted. FIG. 10 is an explanatory view in a side view showing a second embodiment of a collision avoidance structure for a fixing unit pulled out from an apparatus main body with respect to a paper transport unit, and (A) is a state in which the fixing unit is set at a storage position; ) Shows a state in which the fixing unit is set to the drawing position. It is a perspective view which shows the state (namely, the normal state set to the drawing position) by which the fixing unit by which the collision avoidance structure of 2nd Embodiment was employ | adopted was pulled out from the apparatus main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 101 Rear surface opening 102 Conveying path 103 Conveying roller 104 Support shaft 105 Shelf part 11 Equipment body 12 Image forming unit (image forming part)
12M Magenta unit 12C Cyan unit 12Y Yellow unit 12K Black unit 13 Developing device 14 Photosensitive drum 15 Charging unit 16 Exposure unit 17 Cleaning mechanism 18 Paper feed mechanism 19 Paper discharge tray 20 Intra-unit transport unit 21 Base 22 Transport Belt 23 Drive roller 24 Driven roller 25 Rolling roller 30 Fixing unit (fixing unit) 301 Guide rail 302 Fixed fin 31 Housing 32 Fixing roller 33 Heating roller 34 Pressure roller 35 Slide rod 351 Tip 352 Horizontal shaft 353 Guided protrusion 36 Grip member 37 Projection support member 40 Paper transport unit (downstream transport path)
41 transport unit main body 411 supported hole 412 upper transport path 413 lower transport path 414 sheet discharge port 415 side wall 42 lower sheet discharge direction switching member 421 direction switching fin 422 direction switching shaft 43 upper sheet discharge direction switching member 431 direction switching fin 432 Cross shaft 44 Mounting recess 45 Protective protrusion (protective protrusion) 46 Conveying roller pair 47, 49 Conveying roller 48 Cover body 50 Conveying unit 501 Fixed fin 51 Conveying unit main body 52 Conveying unit conveying path 53 Conveying roller pair

Claims (8)

In an image forming apparatus that is provided in a sheet conveyance path in the apparatus main body and discharges a sheet through an image forming unit that transfers an image and a fixing unit that fixes a transferred image.
A downstream conveyance path portion that is a part of the sheet conveyance path and is formed immediately on the side wall of the apparatus main body with a downstream portion in the sheet conveyance direction of the fixing unit, and the downstream conveyance path section with respect to the apparatus main body. An image forming apparatus comprising: an opening / closing mechanism capable of opening / closing; and a slide mechanism capable of reciprocating in the direction of the one side wall so as to expose the fixing unit from the apparatus main body.   The image forming apparatus according to claim 1, wherein a protective protrusion is formed at a suitable position on the inner surface of the one side wall.   3. The image forming apparatus according to claim 1, wherein a sheet conveyance path is formed between the downstream conveyance path section and the fixing section in a state where the downstream conveyance path section is closed.   The downstream conveyance path section includes a direction switching member that switches a direction between a direction parallel to the one side wall and a direction intersecting with the direction with the downstream conveyance path section closed. The image forming apparatus according to claim 1.   The downstream transport path section is provided with a recess in which a transport unit used for transporting a sheet to a predetermined duplex unit when double-sided transfer is performed can be mounted. 5. The image forming apparatus according to any one of 4 above.   The image forming apparatus according to claim 5, wherein the apparatus main body is provided with a mechanism for reversing the paper derived from the transport unit.   7. The projecting member according to claim 1, wherein the fixing unit is provided with a projecting member that prevents interference with a facing surface of the downstream conveyance path unit in a state of being pulled out from the apparatus main body. The image forming apparatus described in 1.   The projecting support member is pivotally supported on a lower side portion of the fixing unit so as to be rotatable around a predetermined axis, and the fixing unit is pushed into the apparatus main body so that the shaft is interfered with the apparatus main body. The fixing unit is rotated in one direction and set in the storage posture, while the fixing unit is rotated in the other direction around the axis and suspended from the axis due to the cancellation of the interference caused by being pulled out from the apparatus main body. 8. The image forming apparatus according to claim 7, wherein the posture is set to a hanging posture.