JP5075485B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus configured to form an image based on image information, transfer a toner image onto a sheet, and discharge the sheet after fixing processing to the outside. The present invention relates to an image forming apparatus that can be performed quickly and appropriately.

  Conventionally, an image forming apparatus capable of double-sided printing as described in Patent Document 1 is known. This image forming apparatus is used as a copying machine, a facsimile machine, a printer, or the like, and is particularly configured to perform double-sided printing on paper. In such an image forming apparatus, a sheet cassette for storing a plurality of sheets (sheet bundle) is provided at the lower part of the apparatus main body, and an image forming unit including a photosensitive drum is disposed above the sheet cassette. It is installed. In addition, a fixing unit is provided in the upper part on the downstream side of the image forming unit.

  The sheets fed one by one from the sheet bundle in the sheet cassette are fed to the upper image forming unit, and the toner image on the photosensitive drum is transferred while moving in the horizontal direction. The sheet after the transfer process is conveyed along a vertical conveyance path that extends upward from the downstream end of the image forming unit. After the fixing process is performed by the fixing unit, the sheet is discharged to a sheet discharge tray. The photosensitive drum is provided facing the vertical conveyance path.

  In such an image forming apparatus, a maintenance door (carrying path section cover in Patent Document 1) is provided on the wall surface corresponding to the sheet conveying path between the downstream end of the image forming section and the fixing section in the apparatus main body. . When a paper jam occurs at this position, the cover member is opened and the jammed paper is removed.

  By the way, in the case of an image forming apparatus configured to be able to perform double-sided printing, such as the image forming apparatus described in Patent Document 1, paper that has been subjected to printing processing on the front side by passing through the fixing unit is temporarily discharged. After being transported to just before being ejected to the paper tray, it is fed back through a bypass transport path that bypasses the fixing unit, and is introduced into a duplex unit having a reverse transport path formed between the image forming unit and the paper tray. The Thereafter, the paper in the reverse conveyance path is sequentially fed from the bottom to the vertical conveyance path with the front and back sides reversed. As a result, the toner image is transferred from the photosensitive drum facing the vertical conveyance path to the back surface of the sheet.

  In such an image forming apparatus for double-sided printing, when the paper being reversely fed is jammed while being positioned between the bypass conveyance path and the duplex unit, the duplex unit is inadvertently pulled out from the apparatus body. When the paper is taken out, the paper is divided between the bypass conveyance path and the duplex unit, so-called tearing phenomenon occurs. This makes the paper jam complicated and makes it difficult to clear the jam. Inconvenience arises.

In order to eliminate such inconvenience, Patent Document 1 is provided to lock the double-sided unit so that it cannot be pulled out unless the cover member is opened (paragraph [0002] of Patent Document 1). It is described that the handle is immersed in the duplex unit (paragraph [0004] of Patent Document 1).
JP-A-8-2704

  By the way, the place where the paper jam easily occurs in the image forming unit is not only between the bypass conveyance path and the duplex unit, but also between the paper tray and the vertical conveyance path. The reason is that the space between the paper tray and the vertical conveyance path is a portion where the conveyance direction of the paper is changed from the horizontal direction to the vertical direction.

  In an image forming apparatus in which a transport unit that can be inserted into and removed from the apparatus main body is used for transporting paper in the image forming unit, the paper is placed between the transport unit and the vertical transport path. When a jam occurs, the cover member (carrying path section cover in Cited Document 1) is opened, and if the conveyance unit is inadvertently pulled out of the main body without removing the paper jam from the vertical conveyance path, Has the disadvantage of breaking. This inconvenience is not solved even if an interlock structure is employed between the duplex unit and the cover member.

  The present invention has been made in view of such a situation, and provides an image forming apparatus capable of preventing breakage of a sheet at the time of paper jam removal processing when a paper jam occurs between a transport unit and a vertical transport path. The purpose is to do.

The invention according to claim 1 is an image forming apparatus configured to transfer a toner image formed by an image forming process based on image information in an image forming unit provided in a predetermined apparatus main body to a sheet. The apparatus main body is interposed between the paper tray on which the transfer processing paper is placed, the paper tray and the image forming unit, and the paper on the paper tray is transferred to the image forming unit. A transport unit that can be inserted into and removed from the apparatus main body, a cover member that is openable and closable provided on a wall surface of the apparatus main body facing the downstream end of the transport unit, and the cover member is closed. Is provided between the inner surface side of the cover member and the image forming unit, and is provided with a vertical transport path for transporting the paper from the transport unit upward. Between the unit, the locking mechanism to prevent the drawer from the apparatus main body of the transport unit in a state where the cover member is closed is provided, wherein the locking mechanism relative to the conveying unit by opening and closing operation of said cover member The lock rod moves forward and backward, and the lock rod interferes with the transport unit when the cover member is closed, while the interference with the transport unit is eliminated when the cover member is opened. The lock rod has a lock rod main body on the cover member side, an advance / retreat rod installed on the transfer unit side of the lock rod main body so as to advance and retreat, and the advance / retreat rod. And an urging member that urges toward the transport unit .

  According to such a configuration, when the cover member is closed, the lock mechanism prevents the conveyance unit from being pulled out from the apparatus main body, so that there is paper between the vertical conveyance path inside the cover member and the conveyance unit. In this state, the transport unit is not pulled out from the apparatus main body. Accordingly, it is possible to prevent the jammed sheet from being separated by pulling out the transport unit in a state where the sheet is jammed, and it is possible to prevent the occurrence of inconvenience that makes it difficult to handle the jam. In addition, when a paper jam occurs, the user can recognize that the cover member must be opened because the transport unit cannot be pulled out, which contributes to improving the workability of the jam clearing operation.

For this reason, when the jam processing is performed, the cover member is first opened. Thus, the jammed paper can be pulled out from the vertical conveyance path side and removed from the connection position between the conveyance unit and the vertical conveyance path. In this state, it is possible to pull out the transport unit and perform a paper jam clearing operation from the transport unit side.
Further, according to the above configuration, in the state where the cover member is closed, the lock rod interferes with the transport unit, which prevents the transport unit from being pulled out from the apparatus main body, and thus the cover member is closed. In spite of this, the transport unit is not inadvertently pulled out of the apparatus main body. On the other hand, in the state where the cover member is opened, the interference with the transport unit of the lock rod is eliminated, so that the transport unit can be pulled out from the apparatus main body.
Furthermore, according to the above configuration, the transport unit is pushed into the apparatus main body after the transport unit is pulled out of the apparatus main body by unlocking the lock rod by opening the cover member and a predetermined maintenance operation is performed. Even if the cover member is closed prior to being pushed, the forward / backward rod is urged from the lock rod body toward the conveyance unit by the urging force of the urging member when the conveyance unit is pushed into the apparatus main body. Since the front end of the roller is pressed against and brought into contact with the transport unit relatively and retreats against the biasing force of the biasing member, the transport unit is pushed into the apparatus main body without being blocked by the lock rod, and then It is locked by the lock rod that has been advanced by the biasing force of the correction member.
In this way, the lock rod is composed of the lock rod body on the cover member side and the advance / retreat rod installed to be able to advance and retreat on the transport unit side of the lock rod body, and the advance / retreat rod is in a state where the cover member is closed. Since it is possible to proceed with the urging force of the urging member after interfering with the pushing operation of the conveying unit into the main body of the apparatus, the opened cover member can be moved ahead of the conveying unit that has been pulled out. Even in the closed state, the transport unit can be pushed into the apparatus main body by the reciprocating movement of the advance / retreat rod and locked by the lock rod.
Therefore, with regard to the order of closing and pushing operations of the cover member opened during maintenance work and the pulled-out conveyance unit, it is not necessary to force the user to first close the cover member after pushing the conveyance unit. The degree of freedom increases and the workability of maintenance work improves.

  According to a second aspect of the present invention, in the first aspect of the present invention, the lock mechanism includes a lock rod that moves forward and backward relative to the transport unit by opening and closing the cover member, and the lock rod includes the cover The length dimension is set so that the interference with the transport unit is canceled when the cover member is opened while the member interferes with the transport unit when the member is closed It is.

  According to such a configuration, when the cover member is closed, the lock rod interferes with the transport unit, which prevents the transport unit from being pulled out of the apparatus main body, and thus the cover member is closed. Nevertheless, the transport unit is not inadvertently pulled out from the apparatus main body.

  On the other hand, in the state where the cover member is opened, the interference with the transport unit of the lock rod is eliminated, so that the transport unit can be pulled out from the apparatus main body.

According to a second aspect of the invention, in the invention according to the first aspect, before SL on the tip portion of the reciprocating rod is inclined guide surface inclined in the direction pushing the transport unit toward the tip from the surface of the transfer unit side pulled out Is provided.

According to such a configuration, the leading end portion of the advance / retreat rod is provided with the guide inclined surface that is inclined in the pushing-in direction of the transport unit from the drawn surface on the transport unit side toward the front end, so that the cover member is opened. After the transport unit is pulled out from the apparatus main body by unlocking the lock rod and a predetermined maintenance work is performed, the cover member is closed before the transport unit is pushed into the apparatus main body. However, when the transport unit is pushed into the apparatus main body, the guide inclined surface at the tip of the forward / backward rod that is biased toward the transport unit from the lock rod body by the biasing force of the biasing member is relatively pressed against the transport unit. Since the contact unit retreats against the urging force of the urging member by the contact, the transport unit is not blocked by the lock rod, and the apparatus main body Pushed in, then, it is locked by a lock rod which is advanced by the urging force of the correcting member.

Thus, the distal end portion of the advance withdrawal rods, in a state where the cover member is closed, so as to proceed with the urging force of the pushing operation as interference to once regressed later biasing member to the apparatus body of the transport unit By providing the guide inclined surface, even if the opened cover member is closed before the transport unit that has been pulled out, the transport unit is pushed back and forth into the main body of the device by the reciprocating movement of the forward and backward rod. Can be locked.

  Therefore, with regard to the order of closing and pushing operations of the cover member opened during maintenance work and the pulled-out conveyance unit, it is not necessary to force the user to first close the cover member after pushing the conveyance unit. The degree of freedom increases and the workability of maintenance work improves.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the apparatus main body is provided with an openable / closable front door facing the cover member, and between the front door and the cover member. Is characterized in that a reverse conveyance path for reversely feeding the paper during the double-sided printing process is formed.

  According to such a configuration, after ensuring the beauty of the external appearance of the apparatus main body by the front door, a reverse conveyance path used during the double-sided printing process is formed between the front door and the cover member. Compared to the case where a dedicated reverse conveyance path is provided on the apparatus main body side, the number of parts can be reduced, which contributes to a reduction in apparatus cost.

  According to the image forming apparatus of the present invention, when the cover member provided in the apparatus main body is closed, the conveyance unit cannot be pulled out from the apparatus main body due to the lock mechanism being locked. In this way, it is possible to perform a paper jam clearing operation while preventing the occurrence of inconvenience that the jammed paper is divided.

  In particular, the lock rod is composed of a lock rod body on the cover member side and an advancing and retreating rod connected to the lock rod body and reciprocating by a pushing operation to the apparatus body of the transport unit, so that it can be released during maintenance work. It is no longer necessary to determine the order of closing the cover member and the drawn-out transport unit and pushing them into the main body, so that the degree of freedom of these operations is increased, resulting in maintenance work such as paper jam clearing work. Can be improved.

  FIG. 1 is a perspective view showing an embodiment of an image forming apparatus 10 according to the present invention, and shows a state where a front cover is removed. FIG. 2 is an explanatory diagram of a front sectional view for explaining the internal structure of the image forming apparatus 10. 1 and 2, the XX direction is referred to as the left-right direction, and the Y-Y direction is referred to as the front-rear direction. In particular, the -X direction is leftward, the + X direction is rightward, the -Y direction is frontward, and the + Y direction is rearward. That's it.

  First, as shown in FIG. 1, the image forming apparatus 10 is a so-called in-body discharge type copier, and includes an image forming unit 12, a fixing unit 13, and a sheet storage unit 14 in the apparatus main body 11. A paper discharge unit 15, an image reading unit 16, and an operation unit 17 are formed. Then, a part of the apparatus main body 11 is recessed at the lower part of the image reading unit 16 to form the paper discharge unit 15, whereby the image forming apparatus 10 is called an in-body paper discharge type.

  The apparatus main body 11 includes a lower main body 111 having a rectangular parallelepiped shape in appearance, an upper main body 112 having a flat rectangular parallelepiped shape disposed above the lower main body 111, and the upper main body 112 and the lower main body 111. And a connecting portion 113 interposed therebetween. The connecting portion 113 is a structure for connecting the paper discharge portion 15 between the lower main body 111 and the upper main body 112 to each other, and is erected from the left portion of the lower main body 111. Yes. The upper body 112 is supported on the upper end of the connecting part 113 at the left side.

  The lower main body 111 includes an image forming unit 12, a fixing unit 13, and a paper storage unit 14, and an image reading unit 16 is mounted on the upper main body 112. In the present embodiment, the operation portion 17 is provided so as to protrude forward from the front edge portion of the upper main body 112.

  The paper storage unit 14 includes a paper cassette 141 that can be inserted into and removed from the apparatus main body 11. The sheet cassette 141 stores a sheet bundle P1 (FIG. 2). When the image forming process is performed, the sheets P are fed out from the sheet bundle P1 one by one, sent to the image forming unit 12, and the sheet P is subjected to the printing process. In the present embodiment, the paper cassette 141 is provided in two stages.

  The paper discharge unit 15 is formed between the lower main body 111 and the upper main body 112. The paper discharge unit 15 has an in-cylinder paper discharge tray 151 formed on the upper surface of the lower main body 111, and the paper P onto which the toner image from the image forming unit 12 is transferred is transferred from the lower part of the connection unit 113 to the cylinder P. The paper is discharged toward the inner paper discharge tray 151.

  The image reading unit 16 includes a contact glass 161 mounted on the upper surface opening of the upper main body 112 for placing a document, and an openable / closable document pressing cover 162 for pressing the document placed on the contact glass 161. And a scanning mechanism 163 that scans an image of the document placed on the contact glass 161.

  Then, the analog information of the document image read by the scanning mechanism 163 is converted into a digital signal and then output to an exposure unit 123 described later, and is subjected to image forming processing.

  The operation unit 17 is used to input processing information related to image forming processing. The operation unit 17 is used to input the number of sheets P to be processed, the numeric keypad 171 and other various operation keys, and further to perform touch input. An LCD (Liquid crystal display) 172 and the like are provided.

  A manual feed tray (paper tray) 18 is provided on the right surface of the lower main body 111 at a position directly above the paper storage unit 14. The lower side of the manual feed tray 18 is pivotally supported around the support shaft 181, and is positioned between a closed posture that stands up to close the manual feed port and an open posture that protrudes rightward. It can be changed. The manual feed tray 18 is used to manually feed the paper P one by one in a state where the posture is set to the open posture.

  A transport unit 30 and a relay unit 40 are provided between the manual feed tray 18 and a photosensitive drum 121 (to be described later) of the image forming unit 12, and a sheet P (FIG. 5) fed manually from the manual feed tray 18. 2) is sent out toward the nip portion between the photosensitive drum 121 and a transfer roller 125 described later via the transport unit 30 and the relay unit 40.

  A maintenance door 19 that can be opened and closed is provided on the left surface of the lower main body 111, and an openable / closable outside discharge tray 152 is provided immediately above the maintenance door 19. Is provided. The paper P for which printing processing has been completed in the image forming unit 12 is selectively discharged to either the out-body discharge tray 152 or the in-body discharge tray 151.

The outline of the internal structure of the image forming apparatus 10 will be described below with reference to FIG. As shown in FIG. 2, the image forming unit 12 is provided with a photosensitive drum 121 at a substantially central portion thereof. The photosensitive drum 121 is uniformly charged on its peripheral surface by a charging unit 122 provided immediately to the right while rotating clockwise around the drum center. Then, an electrostatic latent image on the peripheral surface of the photosensitive drum 121 by the laser beam from the exposure unit 123 that is based on image information read original image by the image reading section 16 is formed. A developer (hereinafter referred to as toner) is supplied from a developing unit 124 provided below the photosensitive drum 121 toward the electrostatic latent image, whereby a toner image is formed on the peripheral surface of the photosensitive drum 121. .

  The sheet P sent out from any one of the sheet cassettes 141 in the sheet storage unit 14 is sent to the photosensitive drum 121 on which the toner image is formed via the sheet vertical conveyance path 101 and the registration roller pair 142. Then, the toner image on the peripheral surface of the photosensitive drum 121 is transferred onto the sheet P by the action of the transfer roller 125 arranged to face the photosensitive drum 121 on the left side of the photosensitive drum 121. The sheet P on which the toner image is transferred is separated from the photosensitive drum 121 and sent to the fixing unit 13.

  After the transfer of the toner image to the paper P is completed, the photosensitive drum 121 is continuously rotated in the clockwise direction, so that its peripheral surface is cleaned by the cleaning device 126 provided immediately above it. The charging unit 122 is headed for the image forming process.

  The fixing unit 13 includes a fixing roller 131 provided with an energization heating element such as a halogen lamp inside, and a pressure roller 132 disposed opposite to the fixing roller 131 on the left side. The sheet P sent from the image forming unit 12 is subjected to a toner image fixing process by obtaining heat while passing through the nip portion between the fixing roller 131 and the pressure roller 132.

  The paper P after the fixing process is selectively placed inside the cylinder of the paper discharge unit 15 via the paper discharge conveyance path 102 provided above the fixing unit 13 when the paper P is for single-sided printing. The paper is discharged to the paper discharge tray 151 or discharged to the out-body discharge tray 152.

  On the other hand, when the sheet P after the fixing process is for double-sided printing in which the single-sided printing process is completed, the first half is discharged into the cylinder via the reciprocating conveyance path 103 provided above the discharge conveyance path 102. After being discharged into a temporary evacuation space 153 formed above the paper tray 151, the paper is reversely fed through a reverse feed path 104, which will be described later, and supplied again to the image forming unit 12 with the front and back sides reversed, and the back side. Is subjected to a printing process. The paper P on which double-sided printing has been completed is discharged to the paper discharge tray 151 or the out-body discharge tray 152.

  In such an image forming apparatus 10, the lower main body 111 is provided with a cover member 20 that can be opened and closed with respect to the image forming unit 12 immediately inside the maintenance door 19. The cover member 20 is disposed in a state of being held on the right side of the closed maintenance door 19. The cover member 20 is pivotally supported around the support shaft 21 supported by the lower body 111 with the lower end portion positioned slightly above the lower end portion of the maintenance door 19. Such a cover member 20 rotates forward and backward around the support shaft 21 to close the left surface of the image forming unit 12 (indicated by a solid line in FIG. 2) and to open the left surface. The posture can be changed between the postures (indicated by a two-dot chain line in FIG. 2).

  In the state where the cover member 20 is set to the closed posture, the sheet vertical conveyance path 101 for conveying the sheet P fed from the sheet cassette 141 or the manual feed tray 18 to the right side of the cover member 20 is provided. Is formed.

  Such a cover member 20 is provided when the paper P is jammed by changing the posture of the cover member 20 to the open position when a paper jam occurs in the paper vertical conveyance path 101 corresponding to the left side of the image forming unit 12. Is exposed to the outside so that the jammed paper P can be removed.

  In addition, when performing double-sided printing on the paper P between the right surface of the maintenance door 19 set in the closed posture and the left surface of the cover member 20 set in the closed posture, only one side is printed. A reverse conveyance path 104 is formed for reversely feeding the paper P subjected to the above. The paper P that has been reversely fed along the reverse feed path 104 is introduced into the vertical paper feed path 101 below the photosensitive drum 121 in a state where the front and back sides are reversed, thereby printing on the back side of the paper P. Processing is performed. The paper P for which double-sided printing has been completed is discharged to the in-body discharge tray 151 or the out-body discharge tray 152.

  In the present embodiment, the paper P that is manually fed from the manual feed tray 18 is fed leftward by the driving of the feed roller 182 provided at the back (left side) of the manual feed tray 18. Then, the sheet is introduced to a position slightly below the photosensitive drum 121 in the sheet vertical conveyance path 101 via the conveyance roller pair 183, the conveyance unit 30 and the relay unit 40.

  The relay unit 40 is formed between a receiving opening facing the downstream end of the transport unit 30 and a discharge opening formed in the right side wall of the paper vertical transport path 101 and is a concave arcuate intermediate transport path 41, the paper P from the transport unit 30 is supplied to the vertical paper transport path 101 through the intermediate transport path 41 in the relay unit 40.

  Accordingly, the paper P manually fed from the manual feed tray 18 is supplied to the image forming unit 12 through the feed roller 182, the transport roller pair 183, the transport unit 30, the intermediate transport path 41 of the relay unit 40, and the paper vertical transport path 101. After the toner image transfer process by the photosensitive drum 121 and the fixing process by the fixing unit 13, the single-sided printing is directly discharged to the paper discharge unit 15, and the double-sided printing is performed on the back side described above. After the processing is performed, the paper is discharged to the paper discharge unit 15.

  The transport unit 30 can be inserted into and removed from the lower main body 111 in the front-rear direction (front and back direction in FIG. 2) so that maintenance work, paper jam clearing work, and the like can be easily performed. ing. A lock mechanism 50 is provided to lock the transport unit 30 so that it cannot be pulled out from the lower body 111 unless the cover member 20 is opened.

  The reason why such a locking mechanism 50 is provided is as follows. That is, when a paper jam occurs in the transport unit 30, the jammed paper P is often located between the transport unit 30 and the vertical paper transport path 101 via the relay unit 40. When the transport unit 30 is pulled out from the lower main body 111 without opening the cover member 20, the upstream side (left side) of the jammed paper P remains in the relay unit 40 and only the downstream side (right side) is transported. This is because the paper 30 is pulled out accompanying the unit 30 and the paper P is divided thereby making it difficult to clear the paper jam.

  In order to prevent such division of the paper P, a lock mechanism 50 is provided that prevents the conveyance unit 30 from being pulled out unless the cover member 20 is opened.

  Hereinafter, the transport unit 30, the relay unit 40, and the lock mechanism 50 will be described with reference to FIGS. FIG. 3 is a partial perspective view in the apparatus main body 11 for explaining the relative positional relationship among the cover member 20, the transport unit 30, the relay unit 40, and the lock mechanism 50, and FIG. It is a perspective view which shows embodiment. FIG. 5 is a view (front view) taken along line V in FIG. 3 and 4 are the same as those in FIG. 1 (X is the left-right direction (-X: leftward, + X: rightward), Y is the front-rear direction (-Y: forward, + Y: backward)).

  The cover member 20 includes a pair of side plates 22 in the front-rear width direction (only the front side plate 22 is shown in FIGS. 2 and 4), and side plates arranged in parallel in the front-rear direction between the pair of side plates 22. 22 and a plurality of conveying fins 23 having substantially the same shape. The side plates 22 and the transport fins 23 have an arcuate shape in which the central portion bulges rightward when viewed from the front, and the transport unit 30 and the relay unit are separated from the manual feed tray 18 by the right edge surfaces of the plurality of transport fins 23. A sheet vertical conveyance path 101 (FIG. 2) for conveying the sheet P fed through 40 toward the photosensitive drum 121 (FIG. 2) is formed.

  The cover member 20 has a lower end set substantially at the same height level as the vertical central portion of the relay unit 40. As a result, the paper P sent out from the relay unit 40 is guided to the plurality of transport fins 23 and introduced into the paper vertical transport path 101 while changing the direction from the horizontal direction to the vertical direction.

  The support shaft 21 that pivotally supports the cover member 20 is provided at the lower end portion of the cover member 20 so as to penetrate the side plate 22 and the transport fin 23, and the front and rear end portions thereof are not shown in the front and rear frames of the apparatus main body 11. It is supported. As a result, the cover member 20 is rotated forward and backward around the support shaft 21 to change the posture between a closed posture (indicated by a solid line in FIG. 2) and an open posture (indicated by a two-dot chain line in FIG. 2). Can do.

  The relay unit 40 is installed on a partition plate 114 that partitions the sheet storage unit 14 (FIG. 2) and the image forming unit 12 in the apparatus main body 11. The relay unit 40 has a substantially rectangular shape when viewed from the front, and a pair of side plates 41 in the front-rear width direction (only the front side plate 41 is shown in FIG. 3) and the front-rear direction between the pair of side plates 41. And a plurality of upper transfer fins 42 and lower transfer fins 43 (FIG. 5) having substantially the same shape.

  Between the upper conveyance fins 42 and the lower conveyance fins 43, a relay unit internal conveyance path 44 is formed so as to be recessed upward so that the downstream end faces the vertical sheet conveyance path 101. Accordingly, the sheet P sent from the transport unit 30 to the relay unit 40 passes through the relay unit transport path 44 and is sent from the downstream end toward the sheet vertical transport path 101.

  As shown in FIG. 4, the transport unit 30 is detachably attached to the apparatus main body 11 on the partition plate 114 immediately upstream of the relay unit 40. The transport unit 30 has a substantially rectangular shape that is long in the left-right direction when viewed from the front, and includes a pair of side plates 31 in the front-rear width direction (only the front side plate 31 is shown in FIG. 3), A plurality of upper transport fins 32 and lower transport fins 33 (FIG. 5) having substantially the same shape as the side plates 31 arranged in parallel in the front-rear direction between the side plates 31 are provided.

  Between the upper transport fin 32 and the lower transport fin 33, a transport path 34 in the transport unit extending in the substantially horizontal direction is formed. Accordingly, the paper P sent from the manual feed tray 18 to the transport unit 30 via the feed roller 182 and the transport roller pair 183 (FIG. 2) passes through the transport path 34 in the transport unit, and from the downstream end of the relay unit 40. It is sent out toward the transport path 44 in the relay unit.

  Between the pair of side plates 31, a pair of upper and lower upstream rollers 35 that support the pair of upper and lower upstream conveying rollers 35 concentrically with the conveying path 34 in the conveying unit being sandwiched slightly to the right of the center in the front-rear direction. A pair of upper and lower downstream roller shafts 361 that support the same pair of upper and lower downstream conveying rollers 36 concentrically is installed at the left end position. The peripheral surfaces of the upstream and downstream conveying roller pairs 35 and 36 are in contact with each other.

  In the upper part of the pair of upstream roller shafts 351, an upstream pulley 352 (FIG. 4) is concentrically and externally fitted to the rear end penetrating the rear side plate 31 so as to be integrally rotatable. In the upper part of the pair of downstream roller shafts 361, a downstream pulley 362 (FIG. 4) is fitted concentrically and integrally and rotatably at a rear end that penetrates the rear side plate 31. A communication belt 37 is wound around the upstream pulley 352 and the downstream pulley 362.

  Further, a driven gear 363 that is concentrically and integrally rotatable around the shaft center is attached to the rear side of the downstream pulley 362 in the upper downstream roller shaft 361. The driven gear 363 is transmitted with a driving force of a driving motor (not shown) provided at an appropriate position in the apparatus main body 11, whereby the upper downstream roller shaft 361 rotates about its axis, and this rotation Then, it is transmitted to the upstream pulley 352 and the upper upstream roller shaft 351 via the connecting belt 37, whereby the upstream roller shaft 351 also rotates in the same direction simultaneously with the downstream roller shaft 361.

  The upstream transport by the synchronous rotation of the upstream and downstream roller shafts 351, 361 and the paper P introduced into the transport path 34 in the transport unit by the synchronous rotation of the pair of downstream transport rollers 35, 36 are transported upstream and downstream. The paper is transported toward the relay unit 40 through the transport path 34 in the transport unit while being sandwiched between the pair of downstream transport rollers 35 and 36.

  In the present embodiment, a transport dial 38 that is concentrically and integrally rotatable is provided at the front end of the upper upstream roller shaft 351. The transport dial 38 is rotated when a paper jam occurs in the transport path 34 in the transport unit. The transport dial 38 is clogged by the rotation of the upstream and downstream transport roller pairs 35 and 36 by the rotation operation. The paper P that is present is discharged.

  In addition, the front side plate 31 is provided with a handle 311 having a U-shape in a rear view at a substantially central position thereof. The handle 311 is used for gripping the transport unit 30 when it is pulled out of the apparatus main body 11 during maintenance work or when a paper jam occurs in the transport unit 30.

  Further, between the pair of side plates 31, a shaft support corner member 312 is installed at the lower portion of the left position for supporting the lower downstream roller shaft 361. A lock groove 313 is provided at the front end portion of the shaft support member 312 and is recessed in a state of being cut from the left surface for fitting a left end portion of a lock rod 52 described later.

  The lock mechanism 50 is for locking the movement of the transport unit 30 so that the transport unit 30 cannot be pulled out from the apparatus main body 11 in a state where the cover member 20 is set to the closed posture. The lock mechanism 50 is provided in front of the relay unit 40 on the partition plate 114 and between the cover member 20 and the transport unit 30.

  Hereinafter, the lock mechanism 50 of the first embodiment will be described based on FIG. 6 and with reference to FIGS. 1 to 5 as necessary. 6A and 6B are perspective views showing the first embodiment of the lock mechanism 50. FIG. 6A is a partially cutaway exploded perspective view, and FIG. 6B is an assembled perspective view. The direction display by X and Y in FIG. 6 is the same as in FIG. 1 (X is the left-right direction (−X: leftward, + X: rightward), Y is the front-rear direction (−Y: forward, + Y: rearward). )).

  First, as shown in FIG. 6A, the lock mechanism 50 includes a rectangular parallelepiped frame 51 that has a rectangular shape in plan view, a lock rod 52 that is attached to the frame 51 in a penetrating state, and the lock mechanism 50. A flange 53 that is externally fitted and fixed to the rod 52 and a coil spring 54 that is compressed and fitted to the lock rod 52 in the frame 51 are provided. The flange 53 is provided with a square hole 531 through which the lock rod 52 is slidably contacted.

  The frame 51 includes a vertically long rectangular left surface plate 511, a right surface plate 512 having the same shape facing the left surface plate 511 on the right side, and a front edge of the left surface plate 511 and the right surface plate 512. A front plate 513 that is long in the left-right direction, and a rear plate 514 having the same shape as the front plate 513 provided between the rear edges. Each of the lower edge portions of the left surface plate 511 and the right surface plate 512 has a locking projection piece 515 protruding downward, and these locking projection pieces 515 are formed in the partition plate 114 of the apparatus main body 11. The lock mechanism 50 is fixed to the partition plate 114 by being press-fitted into the not-illustrated locking hole.

  Further, an upper insertion hole 516 through which the lock rod 52 is inserted is provided at an upper position of the left face plate 511, and a lower insertion hole 517 is provided at a position slightly below the center of the right face plate 512 in the vertical direction. It is installed. These upper and lower insertion holes 516 and 517 are for inserting the lock rod 52.

  In these upper and lower insertion holes 516 and 517, an extension line extending to the left of the straight line connecting the respective center positions abuts on the right edge of the side plate 22, and an extension line extending to the right side is the lock groove 313 (FIG. 4). The penetrating position is set so as to go to.

  As shown in FIG. 5, the lock rod 52 is inserted into the upper and lower insertion holes 516 and 517, and as shown in FIG. 5, the right lower inclined edge 221 of the side plate 22 in front of the cover member 20 set in the closed posture. The length dimension is set so that the upper end portion of the lock groove 313 (FIG. 4) is recessed in the shaft support corner member 312 of the transport unit 30.

  The flange 53 that is externally fitted and fixed to the lock rod 52 is configured such that the lock rod 52 is inserted into the upper and lower insertion holes 516 and 517 and the cover member 20 is set in the closed posture. The installation position is set so as to be located immediately to the right of the upper insertion hole 516.

  The coil spring 54 is set to be slightly longer than the distance between the center positions of the upper and lower insertion holes 516 and 517. Therefore, it is compressed and elastically deformed by being mounted in the frame 51 while being fitted on the lock rod 52.

  The coil spring 54 is fitted in a compressed state between the flange 53 and the right side plate 512 in a state where the flange 53 is in contact with the right side of the left side plate 511. In this state, the lock rod 52 is attached to the left side plate 511. The upper insertion hole 516, the square hole 531 of the flange 53, and the lower insertion hole 517 of the right face plate 512 are inserted, and finally the flange 53 is fixed to a predetermined position of the lock rod 52 with a welding stopper, thereby FIG. As shown in B), the frame 51 is attached.

  In the present embodiment, the rear plate 514 is provided with a cut groove 514a cut downward from the upper edge, and the flange 53 is welded to the lock rod 52 via the cut groove 514a. Is given.

  7A and 7B are explanatory views for explaining the operation of the lock mechanism 50. FIG. 7A shows a state in which the cover member 20 is set to the closed posture, and FIG. Each of the states set to the open posture is shown. Note that the direction display by X in FIG. 7 is the same as in FIG. 1 (−X: leftward, + X: rightward).

  First, as shown in FIG. 7A, in the state where the cover member 20 is set to the closed posture, the right lower inclined edge 221 of the side plate 22 of the cover member 20 resists the biasing force of the coil spring 54. Thus, the lock rod 52 is pressed rightward, whereby the amount of protrusion of the lock rod 52 from the frame 51 obliquely downward to the right increases, and the right end portion of the lock rod 52 is supported by the shaft of the transport unit 30. Since the lock state is fitted into the lock groove 313 of the square member 312, the transport unit 30 cannot be pulled out from the apparatus main body 11.

  Incidentally, when the cover member 20 is set in the closed posture, the closed posture of the cover member 20 is maintained by the locking by the locking means (not shown) provided at an appropriate position of the cover member 20, By performing a predetermined operation on the means, the locked state is released and the cover member 20 can be opened.

  Therefore, when the cover member 20 is set in the closed posture, and a paper jam occurs in the state extending from the transport unit 30 to the relay unit 40, the transport unit 30 is erroneously prior to opening the cover member 20. Even if an attempt is made to pull out the printer unit 11 from the apparatus main body 11, the conveyance unit 30 is not pulled out, so that the inconvenience that the jammed paper P breaks due to tearing is prevented.

  On the other hand, when a paper jam occurs, as shown in FIG. 7B, when the cover member 20 is opened in advance, the pressing of the cover member 20 against the left end portion of the lock rod 52 is released. The rod 52 receives the urging force of the coil spring 54 via the flange 53, and thereby moves to the left. By this movement, the right end portion of the lock rod 52 is disengaged from the lock groove 313 of the transport unit 30, so that the transport unit 30 can be pulled out forward (the front side of the paper surface in FIG. 7).

  Accordingly, once the cover member 20 is opened, the jammed sheet P is pulled out from the cover member 20 side by a predetermined length, and the transport unit 30 is pulled out with the downstream end of the sheet P moved from the transport unit 30 to the relay unit 40 side. Since the paper P remains in the relay unit 40 without breaking, the clogging can be cleared from the transport unit 30 side in this state, and the efficiency of the paper jam clearing work can be improved without breaking the paper P. Realize.

  Hereinafter, the lock mechanism 50 'according to the second embodiment will be described with reference to FIGS. FIG. 8 is a perspective view showing a second embodiment of the lock mechanism 50 ′, FIG. 8A is an exploded perspective view, and FIG. 8B is an assembled perspective view. 9 is a cross-sectional view of FIG. 8B, FIG. 9A is a cross-sectional view taken along line IX (A) -IX (A), and FIG. 9B is a cross-sectional view of IX (B) -IX. (B) It is line sectional drawing. The large circle in FIG. 9A is an enlarged view of the small circle marked on the lock rod 52 ′. The direction display by X and Y in FIGS. 8 and 9 is the same as in FIG. 6 (X is the left-right direction (−X: leftward, + X: rightward), Y is the front-back direction (−Y: forward, + Y: Back)).

  First, as shown in FIG. 8 (A), the lock mechanism 50 'of the second embodiment is mounted in a frame 51' having a rectangular parallelepiped shape in an assembled state, and in a penetrating manner to the frame 51 '. A lock rod 52 ', a large-diameter coil spring 54' that is externally compressed by the lock rod 52 ', and a small-diameter coil spring 57 that is internally fitted in the lock rod 52' in a compressed state.

  The frame body 51 ′ includes a frame body 510 that has a U shape in plan view, and a lid body 518 that closes the rear surface opening of the frame body 510. The frame body 510 includes a vertically long rectangular left surface plate 511, a right surface plate 512 having the same shape facing the left surface plate 511 on the right side, and between the front edge portions of the left surface plate 511 and the right surface plate 512. A front plate 513 that is long in the left-right direction is provided.

  Each of the lower edge portions of the left surface plate 511 and the right surface plate 512 has locking projections 515 projecting downward, and these locking projections 515 are partition plates 114 (FIG. 3) of the apparatus main body 11. ), The lock mechanism 50 ′ is fixed to the partition plate 114.

  Further, an upper notch groove 516 ′ formed by being cut out from the rear edge portion for inserting the lock rod 52 is recessed in the upper position of the left surface plate 511, and the upper and lower surfaces of the right surface plate 512 are A lower notch groove 517 ′ is recessed at a position slightly below the center in the direction. These upper and lower cutout grooves 516 'and 517' are for inserting the lock rod 52 '.

  In these upper and lower cutout grooves 516 'and 517', an extension line extending to the left of the straight line connecting the respective center positions hits the right edge portion of the side plate 22, and an extension line extending to the right side of the notch groove 313 ( The installation position is set so as to go to FIG.

  The lid body 518 is set in a rectangular shape having the same dimensions as the front plate 513. The lid body 518 is fixed to each rear edge portion of the left side plate 511 and the right side plate 512 of the frame body 510 with an adhesive or a screw. Further, an upper groove closing projection 518a is provided at a position corresponding to the upper notch groove 516 ′ at the left edge of the lid 518, and the lower notch is formed at the right edge of the lid 518. A lower groove closing projection 518b is provided at a position corresponding to the groove 517 ′.

  Then, with the lid 518 attached to the frame body 510, the upper groove closing projection 518a fits into the upper notch groove 516 ', and the lower groove closing projection 518b fits into the lower notch groove 517', As a result, holes for passing the lock rod 52 ′ corresponding to the upper insertion hole 516 and the lower insertion hole 517 of the first embodiment are formed in the upper notch groove 516 ′ and the lower notch groove 517 ′.

  The lock rod 52 ′ includes a lock rod main body 55 on the cover member 20 side (left side), and an advance / retreat rod 56 that is movably attached to the transport unit 30 side (right side) of the lock rod main body 55. . The advance / retreat rod 56 is urged rightward by a small-diameter coil spring 57 in a state where the advance / retreat rod 56 is attached to the lock rod body 55.

  The lock rod body 55 has a rectangular tube shape, and a flange 53 is formed at a substantially central portion in the longitudinal direction. The role of the flange 53 is the same as in the case of the first embodiment, and is for causing interference with the left end portion of the large-diameter coil spring 54 ′ fitted on the lock rod body 55 on the right side of the flange 53. .

  The lock rod main body 55 is provided with a mounting square hole 551 for mounting the advance / retreat rod 56 extending from the right end surface to a position where the flange 53 is provided. Further, a notch window 552 communicating with the mounting square hole 551 is provided slightly to the right of the central portion in the front-rear direction of the lock rod body 55. The notch window 552 is provided with a locking protrusion 553 that protrudes leftward from the right edge.

  The locking protrusion 553 is used to prevent the advance / retreat rod 56 fitted in the mounting square hole 551 from coming off. The left end of the locking protrusion 553 is inserted into the mounting square hole 551. As a result, the forward / backward rod 56 is pushed into the mounting square hole 551, thereby interfering with the front surface and temporarily moving forward. After being elastically deformed, it is restored to its original shape, and the advancement / retraction rod 56 is prevented from coming off by fitting the engagement protrusion 553 into the engagement long hole 563. A back wall 554 is provided at a position substantially corresponding to the flange 53 in the mounting square hole 551.

  Further, a stopper protrusion 555 that protrudes leftward from the flange 53 is provided on the lower surface side of the lock rod body 55. The stopper ridge 555 has a left end abutting on the inner side of the left face plate 511 of the frame 51 'in a state in which the lock rod 52' is mounted on the frame 51 ', whereby the lock rod 52' is further leftward. Is prevented from moving toward.

  The forward / backward rod 56 is set slightly shorter than the distance between the right end surface of the lock rod body 55 and the back wall 554. The advancing / retreating rod 56 is provided so as to protrude from the left end surface of the rectangular column body 561 concentrically to the left side in a substantially square shape in a cross-sectional view inserted in the mounting angular hole 551 in a sliding contact state. A cylindrical body 562 whose diameter is slightly shorter than the length of one side of the prismatic body 561 is formed. The cylindrical body 562 is set to have a slightly smaller diameter than the inner diameter dimension of the small diameter coil spring 57.

  In addition, a locking elongated hole 563 extending in the left-right direction is provided at a position corresponding to the locking protrusion 553 on the front surface of the prismatic body 561, and a front end portion (right end portion) of the front surface of the prismatic body 561 is provided. ) Includes a guide inclined surface 564 that is inclined downward toward the rear as it goes to the right (that is, inclined toward the front end from the pulled-out surface on the conveyance unit 30 side toward the front end). Is formed.

  Such a forward / backward rod 56 is inserted into the columnar body 562 with the small-diameter coil spring 57 fitted from the right-side opening of the mounting square hole 551 with the small-diameter coil spring 57 at the top, The small-diameter coil spring 57 stops against the back wall 554 of the mounting square hole 551. By continuing the pushing operation of the advance / retreat rod 56, the advance / retreat rod 56 is pushed into the mounting square hole 551 while the small diameter coil spring 57 is compressed and elastically deformed.

  Then, by this pushing operation, the locking protrusion 553 is once slidably contacted with the front surface of the prismatic body 561 and elastically deformed forward, and then fitted into the locking long hole 563 to be restored to the original state. Therefore, when the advance / retreat rod 56 is fitted into the mounting square hole 551, the advance / retreat rod 56 is engaged with the locking projection piece 553 as shown in a partially enlarged view in FIG. 9A and in FIG. 9B. Is attached to the lock rod body 55 while being urged to the right by the small-diameter coil spring 57 in a retaining state in which the left edge portion is in contact with the left surface of the locking long hole 563.

  The lock rod 52 ′ assembled in this way has an upper portion in which the large-diameter coil spring 54 ′ is externally fitted in a compressed state on the right side and is recessed in the left side plate 511 and the right side plate 512 of the frame body 510. The upper groove closing protrusion 518a and the lower groove closing protrusion 518b of the lid 518 are formed in the upper notch groove 516 'and the lower notch groove 517' in a state of being fitted in the notch groove 516 'and the lower notch groove 517'. As shown in FIGS. 8B and 9, the lock mechanism 50 ′ is completed by being fitted and fixed to the frame main body 510 with the lid 518 fixed with an adhesive or a screw.

  FIG. 10 is a perspective view showing a state in which the lock mechanism 50 ′ according to the second embodiment completed in this way is attached to the partition plate 114 of the apparatus main body 11. The direction display by X and Y in FIG. 10 is the same as in FIG. 3 (X is the left-right direction (−X: leftward, + X: rightward), Y is the front-back direction (−Y: forward, + Y: backward). )).

  As shown in FIG. 10, the state in which the lock mechanism 50 ′ is attached to the partition plate 114 of the apparatus main body 11 is the same as in the case of the lock mechanism 50 of the first embodiment.

Specifically, in a state in which the cover member 20 is closed, the lock rod 52 'with locking rod body 55 left end portion of the are abutting-stops to the right edge of the side plate 22 of the cover member 20, the lock rod 52' The right end portion of the forward / backward rod 56 is fitted into a lock groove 313 provided in the pivotal support member 312 of the transport unit 30, whereby the forward movement of the transport unit 30 is locked.

  In the state where the cover member 20 is opened, the locking stop by the cover member 20 at the right end portion of the lock rod main body 55 is eliminated, so that the lock rod 52 ′ has a large diameter coil spring 54 ′ (FIG. 8). Since it moves to the left by the urging force, the right end portion of the advance / retreat rod 56 is removed from the lock groove 313 by this movement, and the conveyance unit 30 can be pulled out from the inside of the apparatus main body 11 by unlocking by this movement. That is, the lock mechanism 50 'according to the second embodiment locks and unlocks the pull-out operation of the transport unit 30 from the apparatus main body 11, and the lock mechanism according to the first embodiment described above with reference to FIG. 50 is exactly the same.

However, in the lock mechanism 50 according to the first embodiment, the cover member 20 is closed first before the transport unit 30 once pulled out from the apparatus body 11 is pushed into the apparatus body 11. In such a case, the rear end portion of the transport unit 30 interferes with the right end portion of the lock rod 52, thereby causing a problem that the transport unit 30 cannot be stored in the apparatus main body 11.

It is the lock mechanism 50 'according to the second embodiment that eliminates this problem. Hereinafter, the special operation of the lock mechanism 50 'will be described with reference to FIG. Figure 11 is an explanatory view of a planar cross section for explaining the operation of the locking mechanism 50 ', FIG. 11 (A) state in which the transport unit 30 had been fully withdrawn from the inside of the apparatus body 11, FIG. 11 (B) shows a state in which the transport unit 30 has started to be pushed into the apparatus main body 11, and FIG. 11 (C) shows a state in which the transport unit 30 has been pushed into the apparatus main body 11. In FIG. 11, the relative size of the transport unit 30 with respect to the lock mechanism 50 'is considerably smaller than the actual size. In addition, the direction display by X and Y in FIG. 11 is the same as in FIG. 1 (X is the left-right direction (-X: leftward, + X: rightward), Y is the front-back direction (-Y: forward, + Y: rearward). )).

  First, as shown in FIG. 11A, when the cover member 20 is closed with the transport unit 30 pulled out from the apparatus main body 11, the cover member 20 presses the left end of the lock rod main body 55. As a result, the lock rod 52 ′ moves to the right against the urging force of the large-diameter coil spring 54 ′, thereby maximizing the amount of protrusion of the advance / retreat rod 56 toward the right from the frame body 51 ′. ing.

  When the transport unit 30 is pushed into the apparatus main body 11 in this state, the rear corner of the left rear end of the transport unit 30 interferes with the guide inclined surface 564 of the prismatic body 561 of the advance / retreat rod 56, but the push force F When the push-in operation of the transport unit 30 is continued, a component force F1 directed to the left is generated at the advancing / retreating rod 56 at the contact point Q with the guide inclined surface 564 of the left rear corner of the transporting unit 30. It moves to the left against the urging force of the small diameter coil spring 57. Due to the leftward movement of the advance / retreat rod 56, the left end rear corner of the transport unit 30 passes through the guide inclined surface 564 at the right end of the advance / retreat rod 56. Thereafter, the transport unit 30 is pushed into the apparatus main body 11 while its left surface is in sliding contact with the right end of the advance / retreat rod 56.

  When the transport unit 30 is completely pushed into the apparatus main body 11, the lock groove 313 of the transport unit 30 faces the right end of the forward / backward rod 56, so that the forward / backward rod 56 has a small diameter coil spring 57. Due to this urging force, it moves to the right and fits into the lock groove 313, whereby the transport unit 30 enters a locked state that cannot be pulled out unless the cover member 20 is opened.

  As described above, in the lock mechanism 50 ′ of the second embodiment, after the cover member 20 is opened, the transport unit 30 is pulled out from the apparatus main body 11 and a predetermined maintenance operation is performed. Since the transport unit 30 can be pushed into the apparatus main body 11 even if the cover member 20 is closed prior to the pushing operation of the apparatus 30 into the apparatus main body 11, the transport unit 30 is moved to the apparatus main body after the cover member 20 is opened. The workability of the maintenance work that is performed by pulling out from the main body 11 can be improved.

  As described above in detail, the image forming apparatus 10 according to the first and second embodiments described above is the toner formed by the image forming process based on the image information in the image forming unit 12 provided in the apparatus main body 11. The apparatus main body 11 is configured to transfer an image onto the paper P, and transports the paper P sent from the manual feed tray 18 provided in the apparatus main body 11 to the image forming unit 12 by the image forming unit 12. And a cover member 20 that is openable and closable provided on the wall surface of the apparatus main body 11 facing the downstream end of the transport unit 30. The cover member 20 and the transport unit are provided. 30, lock mechanisms 50 and 50 ′ that prevent the conveyance unit 30 from being pulled out from the apparatus main body 11 unless the cover member 20 is opened are provided.

According to such a configuration, when the cover member 20 is closed, the lock mechanisms 50 and 50 ′ prevent the transport unit 30 from being pulled out from the apparatus main body 11, so the paper vertical transport path 101 inside the cover member 20. When the transport unit 30 is pulled out without being pulled out of the apparatus main body 11 in a state where the paper P exists between the printer and the relay unit 40 or between the vertical paper transport path 101 and the transport unit 30 In this case, the jammed paper P is not divided. Therefore, it is possible to prevent the occurrence of inconvenience that the jam processing becomes difficult due to the division of the paper P. Further, the user can recognize that when the paper jam occurs, the cover member 20 must be opened because the transport unit 30 cannot be pulled out.

  For this reason, when the jam processing is performed, the cover member 20 is first opened. By doing so, the jammed paper P can be pulled out from the paper vertical conveyance path 101 side and removed from the connection position between the conveyance unit 30 and the paper vertical conveyance path 101. Moreover, since the lock of the lock mechanisms 50 and 50 ′ with respect to the transport unit 30 is released by opening the cover member 20, the transport unit 30 is pulled out with the paper P removed from the jammed position, and the transport unit 30 is moved to the transport unit 30. Confirmation work and maintenance work can be performed.

  The lock mechanisms 50 and 50 ′ have lock rods 52 and 52 ′ that move forward and backward toward the transport unit 30 by opening and closing the cover member 20, and the cover member 20 is closed by the lock rods 52 and 52 ′. The length dimension is set so that the interference with the transport unit 30 is canceled when the cover member 20 is opened while the interference with the transport unit 30 is made.

  According to such a configuration, when the cover member 20 is closed, the lock rods 52 and 52 ′ interfere with the transport unit 30, so that the transport unit 30 cannot be pulled out from the apparatus main body 11. Although the cover member 20 is closed, the transport unit 30 is not inadvertently pulled out from the apparatus main body 11.

  On the other hand, when the cover member 20 is opened, the interference between the lock rods 52 and 52 ′ and the transport unit 30 is eliminated, so that the transport unit 30 can be pulled out from the apparatus main body 11.

  Further, the apparatus main body 11 is provided with an openable / closable maintenance door 19 facing the cover member 20, and a reverse feed transporting the paper P backward between the maintenance door 19 and the cover member 20 during the duplex printing process. A path 104 is formed.

  According to this configuration, the maintenance door 19 ensures the appearance of the apparatus main body 11 and the reverse conveyance path 104 used between the maintenance door 19 and the cover member 20 during the double-sided printing process. As a result, the number of parts can be reduced and the cost of the apparatus can be reduced as compared with the case where the dedicated reverse conveyance path 104 is provided on the apparatus main body 11 side.

  In particular, the lock mechanism 50 ′ according to the second embodiment includes a lock rod 52 ′, a lock rod main body 55, an advance / retreat rod 56 installed in the lock rod main body 55 so as to be able to advance and retreat, and the advance / retreat rod 56 as a transport unit. A small-diameter coil spring 57 that urges toward the side 30, and the front end of the forward / backward rod 56 interferes with the pushing operation of the transport unit 30 into the apparatus main body 11 with the cover member 20 closed. A guide inclined surface 564 is provided so as to be able to proceed with the urging force of the small-diameter coil spring 57 after retreating once.

  According to this configuration, after the transport unit 30 is pulled out from the apparatus main body 11 and the predetermined maintenance work is performed by unlocking the lock rod 52 ′ by opening the cover member 20, the transport unit 30 is moved to the apparatus. Even when the cover member 20 is closed before being pushed into the main body 11, when the conveyance unit 30 is pushed into the apparatus main body 11, the conveyance unit 30 is moved from the lock rod main body 55 by the urging force of the small-diameter coil spring 57. The guide inclined surface 564 at the tip of the advance / retreat rod 56 urged toward the surface interferes with the transport unit 30, whereby the advance / retreat rod 56 retreats against the urging force of the small diameter coil spring 57. Is pushed into the apparatus main body 11 without being blocked by the lock rod 52 '.

  Thus, the lock rod 52 ′ is constituted by the lock rod main body 55 on the cover member 20 side and the advance / retreat rod 56 movably connected to the transport unit 30 side of the lock rod main body 55. In the state where the cover member 20 is closed at the front end portion, the guide inclined surface 564 is able to proceed with the urging force of the small-diameter coil spring 57 after retreating after interfering with the pushing operation of the transport unit 30 into the apparatus main body 11. Even when the opened cover member 20 is closed before the transport unit 30 that has been pulled out, the transport unit 30 can be pushed into the apparatus main body 11 by the reciprocating movement of the forward / backward rod 56. Is possible.

  Accordingly, it is not necessary to force the user to close the cover member 20 after first pushing the transport unit 30 with respect to the order of closing and pushing operation of the cover member 20 opened during the maintenance work and the transport unit 30 pulled out. As a result, the degree of freedom of these operations is increased and the workability of the maintenance work can be improved.

  The present invention is not limited to the above embodiment, and includes the following contents.

  (1) In the above embodiment, a copying machine has been described as an example of the image forming apparatus 10. However, the present invention is not limited to the image forming apparatus 10 being a copying machine, and may be a printer. There may be a facsimile machine.

  (2) In the above embodiment, the relay unit 40 is interposed between the cover member 20 and the transport unit 30. However, the relay unit 40 is not essential and may not be provided. If the relay unit 40 is not provided, the downstream end of the transport path 34 in the transport unit formed in the transport unit 30 may be formed in a concave shape so as to be along the vertical paper transport path 101 without difficulty. .

  (3) In the above embodiment, only the paper P from the manual feed tray 18 is introduced into the transport unit 30, but the paper P from the paper cassette 141 is reverse to that in FIG. When the sheet cassette 141 is configured to be fed out from the right end portion, the sheet P from the sheet cassette 141 may be sent to the image forming unit 12 via the transport unit 30.

  (4) In the above-described embodiment, the lock rods 52 and 52 ′ of the lock mechanisms 50 and 50 ′ are urged toward the cover member 20 by the urging force of the coil spring 54. Without using the spring 54, the side plate 22 of the cover member 20 and the left end of the lock rods 52, 52 ′ may be linked to each other via a pin provided on the side plate 22 so as to be relatively rotatable. In this way, the lock rods 52 and 52 ′ can be made to follow the opening / closing operation of the transport unit 30 without using the coil spring 54 in particular. Reduction can be realized, and it can contribute to reduction of apparatus cost.

1 is a perspective view showing an embodiment of an image forming apparatus according to the present invention, and shows a state in which a front cover is removed. It is explanatory drawing of front sectional view for demonstrating the internal structure of an image forming apparatus. It is a fragmentary perspective view in the apparatus main body for demonstrating the relative positional relationship of a cover member, a conveyance unit, an intermediate conveyance unit, and a lock mechanism. It is a perspective view which shows one Embodiment of a conveyance unit. It is the figure (front view) of the V line view of FIG. It is a perspective view which shows 1st Embodiment of a locking mechanism, (A) is a partially notched exploded perspective view, (B) is an assembly perspective view. It is explanatory drawing for demonstrating the effect | action of a locking mechanism, (A) shows the state in which the cover member was set to the closed posture, and (B) shows the state in which the cover member was set to the open posture. ing. It is a perspective view which shows 2nd Embodiment of a locking mechanism, (A) is a disassembled perspective view, (B) is an assembly perspective view. 9A is a cross-sectional view of FIG. 8B, FIG. 8A is a cross-sectional view taken along line IX (A) -IX (A), and FIG. 8B is a cross-sectional view taken along line IX (B) -IX (B). It is a perspective view which shows the state with which the locking mechanism which concerns on 2nd Embodiment was mounted | worn with the partition plate of the apparatus main body. It is explanatory drawing of planar sectional view for demonstrating the effect | action of a locking mechanism, (A) is the state by which the conveyance unit was fully pulled out from the inside of an apparatus main body, (B) is a state where a conveyance unit is made into an apparatus main body. A state in which pushing starts, (C) shows a state in which the transport unit is pushed into the apparatus main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 101 Paper vertical conveyance path 102 Paper discharge conveyance path 103 Reciprocation conveyance path 104 Reverse feed conveyance path 11 Apparatus main body 111 Lower main body 112 Upper main body 113 Connection part 114 Partition plate 12 Image formation part 121 Photosensitive drum 122 Charging unit 123 Exposure unit 124 Development unit 125 Transfer roller 126 Cleaning device 13 Fixing unit 131 Fixing roller 132 Pressure roller 14 Paper storage unit 141 Paper cassette 142 Registration roller pair 15 Paper discharge unit 151 In-body discharge tray 152 Out-body discharge tray 153 Temporary Retraction space 16 Image reading unit 161 Contact glass 162 Document pressing cover 163 Scanning mechanism 17 Operation unit 171 Numeric keypad 172 LCD
18 Manual feed tray 181 Support shaft 182 Feed roller 183 Conveying roller pair 19 Maintenance door (front door)
20 cover member 21 support shaft 22 side plate 221 right lower inclined edge 23 transport fin 30 transport unit 31 side plate 311 handle 312 shaft support corner 313 lock groove 32 upper transport fin 33 lower transport fin 34 transport path in transport unit 35 upstream transport roller Pair 351 Upstream roller shaft 352 Upstream pulley 36 Downstream transport roller pair 361 Downstream roller shaft 362 Downstream pulley 363 Driven gear 37 Link belt 38 Transport dial 40 Relay unit 41 Side plate 42 Upper transport fin 43 Lower transport fin 44 Relay unit Inner conveying path 50, 50 ′ Lock mechanism 51, 51 ′ Frame 511 Left side plate 512 Right side plate 513 Front plate 514 Rear plate 514 a Cut groove 515 Locking protrusion 516 Upper insertion hole 516 ′ Upper cut groove 517 Lower insertion hole 517 ′ Lower notch 18 Lid 518a Upper groove closing protrusion 518b Lower groove closing protrusion 52, 52 'Lock rod 53 Flange 531 Square hole 54 Coil spring 54' Large diameter coil spring 55 Lock rod body 551 Mounting square hole 552 Notch window 553 Locking protrusion 554 Back wall 555 Stopper protrusion 56 Advance rod 561 Square column 562 Column 563 Locking long hole 564 Guide inclined surface P Paper P1 Paper bundle

Claims (3)

In an image forming apparatus configured to transfer a toner image formed by an image forming process based on image information in an image forming unit provided in a predetermined apparatus main body to paper,
In the apparatus main body, a paper tray on which the transfer processing paper is placed;
A transport unit that is interposed between the paper tray and the image forming unit, and that can be inserted into and removed from the apparatus main body for directing the paper on the paper tray to the image forming unit;
An openable and closable cover member provided on a wall surface facing the downstream end of the transport unit in the apparatus body;
A vertical conveyance path that is formed between the inner surface side of the cover member and the image forming unit by closing the cover member and conveys the paper from the conveyance unit upward;
Between the cover member and the transport unit, a lock mechanism is provided that prevents the transport unit from being pulled out from the apparatus main body in a state where the cover member is closed ,
The lock mechanism has a lock rod that moves forward and backward with respect to the transport unit by opening and closing the cover member;
The lock rod is configured to have a length dimension so as to interfere with the transport unit when the cover member is closed while eliminating the interference with the transport unit when the cover member is opened. And
The lock rod includes a lock rod body on the cover member side, an advancing / retracting rod installed to be movable toward and away from the transport unit side of the lock rod body, and an urging force for biasing the advance / retreat rod toward the transport unit side. An image forming apparatus comprising: a biasing member . The distal end portion of the front Symbol reciprocating rod, drawn image according to claim 1, wherein the inclined guide surface inclined in the direction pushing the transport unit toward the tip from the surface of the transport unit side, characterized in that it is provided with Forming equipment. The apparatus main body is provided with an openable / closable front door that faces the cover member, and a reverse feed path is formed between the front door and the cover member to reverse the paper during double-sided printing. the image forming apparatus according to claim 1 or 2, characterized in that is.

Images