JP5294808B2 - Transport mechanism of printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer with a switchback function such as double face printing which can be reduced in size and saved in space while securing a reverse path for the switchback function even if an optional function such as an offset paper discharge function is added. <P>SOLUTION: The conveying path of the printer 100 comprises a normal path CR extending from a paper feed path FR a feeding the recording medium to a paper discharge path DR and the reverse path SR which is branched and connected to the normal path CR to which the recording medium is discharged from the normal path, and which reverses the front and rear of the recording medium by forwardly and reversely rotating the conveying mechanism to reciprocate the recording medium and returning the recording medium to the normal path CR. The reverse path SR has a lower guide member 156 for supporting the recording medium from the lower side. The lower guide member 156 is rotatable vertically with respect to the free end at the forward path end side by the forward rotation. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a transport mechanism for a printing apparatus that transports the recording medium in a printing apparatus that forms an image on the surface of the recording medium transported on a transport path.

  In recent years, printing apparatuses such as ink jet printers have a demand for apparatus miniaturization, and there is also a demand for multi-function apparatuses having various functions in a limited space. Here, in recent printing apparatuses, apparatuses capable of performing double-sided printing with a so-called switchback function have been developed. In such a printing apparatus, a space for a paper discharge stand and a switchback function is additionally provided. There is a printing apparatus that reduces the size of the printing apparatus.

In addition, in order to facilitate the sorting of the recording media by the user after paper ejection as the printing apparatus is increased in speed and mass printing, by moving the paper ejection tray horizontally, the number of ejected recording media is increased by a certain number. There is an offset function of laminating while shifting (Patent Document 1).
JP-A-6-78151

  However, in the above-described offset function, when the recording medium is discharged while moving the discharge table, the height position of the discharge table is set in order to properly maintain the stacked state of the recording medium on the discharge table. In some cases, an up-and-down drive mechanism that changes according to the loading amount of the recording medium is provided.

  However, in the above-described apparatus having the paper discharge tray and the switchback function, if the paper discharge tray moves up and down, the space for switchback also changes, and the reverse path can be secured appropriately. There wasn't.

  Therefore, the present invention has been made in view of the above points, and in a printing apparatus having a switchback function such as double-sided printing, for example, even when an optional function such as an offset paper discharge function is added, the switchback is performed. It is an object of the present invention to provide a transport mechanism for a printing apparatus that can reduce the size and space of the apparatus while ensuring a reversing path for the function.

In order to solve the above problems, the present invention provides a transport mechanism for transporting a recording medium in a printing apparatus that forms an image on the surface of the recording medium transported on the transport path, and the transport path supplies the recording medium. The normal path from the paper feed path through the image forming unit to the paper discharge path and the normal path are branched and connected, the recording medium is transferred from the normal path, and the recording mechanism is rotated by rotating the conveyance mechanism forward and backward. A reversing path that reverses the front and back of the recording medium by reciprocating and returning to the normal path . The reversing path has a lower guide member that supports the recording medium from below, and the lower guide member is a forward path by forward rotation. the terminal end has a possible upper and lower swing to a free end, the lower guide member, the conveying mechanism near the reverse path, and the fulcrum member upper and lower swing is pivotally supported, the fulcrum member Corresponding to the swing of Possess a terminating member for vertical movement, the sheet discharge port of the recording medium is discharged in a discharging path termination is located above the space required for the round trip of the recording medium, a paper discharge port, the space required for the reciprocating In the meantime, a cradle on which the recording medium ejected from the paper ejection port is stacked is provided so as to be movable up and down, and the swing of the lower guide member follows the vertical motion of the cradle.

  According to such an invention, in a printing apparatus having a so-called switchback function for performing double-sided printing by reciprocating paper, the lower guide member swings up and down, so that the space for reversing the recording medium has changed. At this time, the reversal path can also be deformed by following this. Thereby, the inversion path | route according to the form or function of each printing apparatus is securable.

The lower guide member is constituted by a member of two different points of operation of the fulcrum side member and the end member, the fulcrum member, so that swings up and down the end point of the transfer mechanism side as an axis, the transport mechanism side The space of the inversion path can be ensured in a fan-shaped range with the end point as. Therefore, the reversing path can be deformed while the transfer function itself is fixed. On the other hand, since the terminal side member can be configured to move up and down, the configuration can be simplified when a mechanism for following up and down such as an offset function is required.

In addition, for example, the space that changes due to the vertical movement of the cradle and the space for reciprocation of the recording medium can be shared by an offset paper discharge mechanism or the like, so that an extra space is eliminated while securing a reverse path. This makes it possible to reduce the size of the printing apparatus.

  In the above invention, it is preferable that the cradle is moved up and down according to the loading amount of the recording medium so that the distance from the upper surface of the loaded recording medium to the paper discharge port is constant. In this case, the distance at which the discharged recording medium falls to the upper surface of the recording medium loaded on the cradle by moving the cradle up and down according to the amount of the recording medium loaded on the cradle. Can be kept constant. Thereby, for example, in the offset paper discharge, it is possible to make the air resistance received when the discharged recording medium falls, avoiding the displacement of the recording medium fall point due to variations in air resistance, Recording media can be matched. As a result, it is possible to sort and stack the discharged recording media while ensuring a reverse path for double-sided printing, and to reduce the burden on the user due to sorting work or the like.

  As described above, according to the structure of the present invention, even if an optional function such as an offset paper discharge function is added to a printing apparatus having a switchback function such as double-sided printing, the switchback function is provided. It is possible to reduce the size and space of the apparatus while securing the reverse path.

(Overall configuration of printing device)
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an outline of a printing paper conveyance path of the printing apparatus 100 according to the present embodiment. In the present embodiment, the printing apparatus 100 includes a plurality of ink heads having a large number of nozzles, prints black or color ink from each ink head, performs printing in units of lines, and prints on a recording sheet on a conveyance belt. An ink-jet line color printer that forms a plurality of images so as to overlap each other will be described as an example.

  As shown in FIG. 1, the printing apparatus 100 is an apparatus that forms an image on the surface of a sheet conveyed on an annular conveyance path. A general path CR from the head unit 110 to the paper discharge path DR and a reverse path SR branched and connected to the normal path CR are roughly configured.

  In the paper feed path FR, as a paper feed mechanism for supplying printing paper, a side paper feed stand 120 disposed outside the side surface of the housing and a plurality of paper feed trays (130a, 130a provided inside the housing) are provided. 130b, 130c, 130d). A paper discharge port 140 is provided as a paper discharge mechanism for discharging printed printing paper.

  Printing paper fed from one of the side paper feeding tray 120 and the paper feeding tray 130 is conveyed along a paper feeding path FR in the housing by a driving mechanism such as a roller, and the leading portion of the printing paper. To the resist portion R which is the reference position. A head unit 110 including a plurality of ink heads is provided further on the registration direction R in the transport direction side. The printing paper is image-formed line by line with ink ejected from each ink head while being conveyed at a speed determined by printing conditions by a conveying belt 160 provided on the opposite surface of the head unit 110.

  The printed printing paper is further conveyed on the normal route CR by a driving mechanism such as a roller. In the case of single-sided printing, in which printing is performed only on one side of the printing paper, the paper is directly discharged to the paper discharge port 140 through the paper discharge route DR, and is discharged as a tray for the paper discharge port 140. It is loaded on the table 150 with the printing surface facing down. The paper discharge table 150 has a tray shape protruding from the housing, and has a certain thickness. The sheet discharge table 150 is inclined, and the printing sheets discharged from the sheet discharge outlet 140 are naturally arranged and stacked by a side wall formed at a position below the inclination.

On the other hand, in the case of double-sided printing in which printing is performed on both sides of the printing paper, the front side (the first printed side is “front side” and the next printed side is “back side”). Without being guided to, the inside of the casing is further transported and sent out to the reverse path SR. For this reason, the printing apparatus 100 is provided with a switching mechanism 170 for switching the transport path for backside printing, and printing paper that has not been sent to the paper discharge path DR by the switching mechanism 170 is drawn into the reversing path SR. .

  In the reversing path SR, a sheet is transferred from the normal path CR, and a so-called switchback is performed in which the sheet is reversed by reciprocating the sheet. Then, it is returned to the normal route CR via the switching mechanism 172 by a driving mechanism such as a roller, is fed again through the registration portion R, and the back side is printed by the same procedure as the front side. After that, the printing paper on which the back side is printed and the image is formed on both sides is guided to the paper discharge port 140 through the paper discharge route DR and discharged, and the paper discharged as a receiving base of the paper discharge port 140 is discharged. It is loaded on the table 150.

  In the present embodiment, switchback at the time of duplex printing is performed using a space provided in the paper discharge tray 150. The paper discharge table 150 is originally provided in the printing apparatus 100, and by performing switchback using the space in the paper discharge table 150, a separate switchback space is provided in the printing apparatus 100. There is no need to provide it. Therefore, an increase in the size of the housing can be prevented. Furthermore, since the paper discharge path and the reverse path are not shared, the switchback process and the paper discharge of other sheets can be performed in parallel.

  In the printing apparatus 100, one-side printed printing paper is also re-fed to the registration portion R, which is the reference position of the leading portion of the fed printing paper, during duplex printing. For this reason, a junction point where a transport path for newly fed printing paper and a refeed path for circulating and feeding back-side printing paper is formed immediately before the registration portion R. The Then, the registration unit R sends out the paper in the vicinity of the junction between the paper feed path FR and the normal path CR.

  In the present embodiment, the path on the sheet feeding mechanism side is defined as the sheet feeding path FR, and the other path is defined as the transport path with reference to the above merging point. This transport path is annular, and includes the normal path CR and the reverse path SR as described above. FIG. 2 is a diagram schematically showing the sheet feeding path FR, the normal path CR, and the reversing path SR. In the figure, the number of rollers constituting the drive unit is omitted as appropriate.

  In the paper feed path FR, the side paper feed driving unit 220 for feeding paper from the side paper feed tray 120 and the tray 1 for feeding paper from the paper feed trays 130 (130a, 130b, 130c, 130d) are provided. A drive unit 230a, a tray 2 drive unit 230b,... Are provided. These constitute a paper feeding means for feeding paper to the registration unit R.

  Further, any of the driving units (tray 1 driving unit 230a, tray 2 driving unit 230b...) In the above-described paper feeding path FR includes a driving mechanism composed of a plurality of rollers and the like, and is loaded on a paper feeding table or a paper feeding tray. The printed sheets are taken one by one and conveyed in the direction of the registration portion R. Each drive unit can be driven independently, and necessary drive unit operations are performed in accordance with a paper feed mechanism that feeds paper.

  In addition, a plurality of transport sensors are arranged in the paper feed path FR so that a paper jam in the paper feed path FR can be detected. That is, each conveyance sensor is a sensor that detects the presence or absence of printing paper or the leading edge of printing paper. For example, a plurality of conveyance sensors are arranged at appropriate intervals on a conveyance path, and a conveyance sensor provided on the paper feeding side is provided. If the conveyance sensor on the conveyance direction side does not detect the printing paper within a predetermined time after detecting the printing paper, it can be determined that the conveyance jam has occurred.

  Among these conveyance sensors, the registration sensor in front of the registration unit R that sends out the paper measures the size of the paper that is being conveyed, and measures the size of the paper that is passing, for example, based on the passage speed and the passage time of the paper. If the conveyance sensor does not detect the printing paper within a predetermined time after driving the side paper feed driving unit 220, the tray 1 driving unit 230a, etc., it is determined that a conveyance jam (paper feeding error) has occurred. Can do.

  The normal path CR is a part of the circulation conveyance path, and is a path from the paper supply path FR for supplying paper to the paper discharge path DR through the head unit 110, and an image is formed on the upper surface of the paper on the normal path CR. Is formed. In the normal path CR, a registration driving unit 240 that guides printing paper to the registration unit R, a belt driving unit 250 that drives the endless movement of the conveyance belt 160 provided on the opposite surface of the head unit 110, and a conveyance direction side in order. The first upper surface transport driving unit 260 and the second upper surface transport driving unit 265, the upper surface discharge driving unit 270 for guiding the printed paper to the paper discharge port 140, and the driving means for drawing the printing paper into the reverse path SR for back surface printing. Is provided. Each drive unit includes a drive mechanism composed of one or a plurality of rollers and the like, and conveys printing sheets one by one along the conveyance path. Each drive unit can be driven independently, and necessary drive unit operations are performed in accordance with the conveyance status of the printing paper.

  Further, a plurality of conveyance sensors are also arranged on the normal route CR so that a conveyance jam in the normal route CR can be detected. Further, it is possible to confirm that the printing paper is properly conveyed also in the registration portion R. In the normal route CR, a conveyance sensor is provided corresponding to the drive unit, and it is possible to specify in which drive unit of the normal route CR the conveyance jam has occurred.

  The reversing path SR is branched and connected to the normal path CR, the paper is delivered from the normal path CR, and the paper is reciprocated (switched back) to return to the normal path CR, thereby reversing the front and back of the paper and the transport mechanism The reversing path SR is provided with a reversing drive unit 281 that reverses the sheet and guides it to the joining point. The reverse route SR can be transported at a speed different from that of the normal route CR. When the paper is taken over from the normal route CR, acceleration / deceleration is performed, and a stop time at the time of switchback is extended or shortened. can do.

  In this embodiment, after a certain printing paper is fed, the next printing paper is not fed after waiting for printing to be performed on the printing paper and discharged. Before the printing paper is discharged, the subsequent printing paper can be fed and printed continuously at a predetermined interval. Therefore, in normal scheduling at the time of duplex printing, a space is secured in advance so as to secure a position where the sheet returned from the reversing path SR is inserted when feeding the front sheet. Thereby, in this apparatus, printing on the front surface and printing on the back surface can be performed in parallel, and half the productivity can be ensured with respect to single-sided printing.

  The conveyor belt 160 is stretched around a driving roller 161 and a driven roller 162 disposed at the front end and rear end of the surface facing the head unit 110, and rotates in the clockwise direction in FIG. Further, on the upper surface of the transport belt 160, ink heads of four colors are arranged side by side along the belt moving direction, and a head unit 110 that forms a color image so as to overlap a plurality of images is opposed to the head unit 110. Yes.

  Further, as illustrated in FIG. 1, the printing apparatus 100 includes an arithmetic processing unit 330. The arithmetic processing unit 330 is configured by a processor such as a CPU or DSP (Digital Signal Processor), memory, hardware such as other electronic circuits, software such as a program having the function, or a combination thereof. Various functional modules are virtually constructed by appropriately reading and executing a program, and various functional modules for processing related to image data, operation control of each unit, and user operations are constructed by each constructed functional module. Process. In addition, an operation panel 340 is connected to the arithmetic processing unit 330, and an instruction and a setting operation by a user can be received through the operation panel 340.

(Offset paper discharge function)
In the present embodiment, an offset paper discharge function can be added to the paper discharge table 150 as an option. 3 and 4 are external views showing the paper discharge table 150 corresponding to the offset paper discharge function, and FIG. 5A is a cross-sectional view showing the internal structure of the paper discharge table 150 from the side.

  As shown in FIG. 6A, the offset paper discharge function is a function of discharging the recording medium discharged from the paper discharge port 140 while shifting the recording medium to the left and right. As shown in FIGS. 7A and 7B, a mechanism for moving the position of the movable tray 151 up and down in accordance with the amount of discharged paper loaded on the paper receiving tray 150 is provided.

  More specifically, the paper discharge port 140 is a paper discharge unit that discharges printed printing paper to the outside of the printing apparatus via the paper discharge route DR. The recording medium is discharged into the paper discharge port 140. For this purpose, a plurality of discharge rollers 141 are provided in the vertical direction. In the present embodiment, as shown in FIG. 6A, when the paper discharge port 140 discharges from the paper discharge port 140, the recording medium 10 is predetermined according to the print contents by the offset function. Each sheet is discharged at a certain distance in the width direction (direction orthogonal to the sheet discharge direction Y) X and stacked on the sheet discharge table 150.

  In the present embodiment, as shown in FIG. 6B, the offset function shifts the movable tray unit 151 to the left and right for each offset number in order to sort the recording medium 10 for each set (offset number). On the movable tray 151, sorting is performed by stacking a stack of recording media while shifting the recording medium to the left and right. The movable tray portion 151 includes a crank gear (not shown) on the back surface thereof, and the crank gear is rotated by a shift motor at a constant time period, whereby a distance corresponding to the diameter of the crank gear is obtained. The part 151 is reciprocated left and right. In this embodiment, the fixed time period is after a fixed time has elapsed since the trailing edge of the set number of sheets has passed through the paper discharge outlet 140.

  The paper discharge table 150 is provided with a movable tray 151 on the top surface of which a recording medium is stacked as a receiving table for the recording medium discharged from the paper discharge port 140. The movable tray 151 has a configuration in which a plate-like upper surface 151a is supported by substantially triangular side walls 151b, and the upper surface 151a is arranged so that the upper surface 151a is substantially parallel to the paper discharge direction Y by both side walls 151b. Inclined towards. The side walls 151b are attached to the casing portion 153 of the paper discharge tray 150 so as to be slidable up and down, and are moved up and down by a tray driving portion 157 provided on the side of the paper discharge tray 150. It has become.

  Such a movable tray 151 corresponds to the above-described offset paper discharge function, so that the distance d from the upper surface 10a of the stacked recording medium 10 to the paper discharge port 140 is constant. A so-called elevator operation that moves up and down according to the load amount of the vehicle is also performed.

  For example, as shown in FIG. 7A, the stack height of the recording medium on the movable tray portion 151 is shown in FIG. 7B from the stack height h1 of a small amount of the recording medium immediately after the discharge is started. As described above, the recording medium stacking height h2 changes as the paper discharge continues. The movable tray unit 151 moves downward by a distance of a difference L (= h2−h1) in accordance with the change in the stacking height. Due to the movement of the movable tray 151, the distance d from the paper discharge outlet 140 to the recording medium upper surface 10a is maintained. Thereby, the air resistance received when the discharged recording medium is dropped can be made constant, and the dropping point of the recording medium is stabilized.

  In this elevator operation, in the present embodiment, the vertical movement is executed every time a predetermined number of sheets is printed (for example, every two sheets). At this time, after the trailing edge of the last sheet (here, the second sheet) passes through the sheet discharge outlet 140, the lowering operation of the movable tray unit 151 is started after a predetermined time has elapsed. Next, when the paper surface sensor for detecting the load on the movable tray 151 is turned off, the lowering of the movable tray 151 is finished, and the movable tray 151 is raised until the paper surface sensor is turned on next time. By repeatedly performing the above operation, the movable tray 151 is always kept at an appropriate position. Note that after the user removes the recording medium, the movable tray 151 automatically moves upward so that the distance d from the discharge outlet 140 to the upper surface 10a of the recording medium stacked on the discharge tray 150 is reached. Controlled to move.

  In the present embodiment, the paper discharge table 150 described above includes a reversing mechanism. FIG. 5 is an explanatory view schematically showing the operation of the reversing mechanism.

  In the present embodiment, as shown in FIG. 5B, the inversion path SR includes an inversion unit SR2 that performs an inversion operation, an outward path SR1 from the normal path CR to the inversion unit SR2, and a normal path from the inversion unit SR2 again. It is composed of a refeed path SR3 up to the CR. The reversing unit SR2 is positioned in a reversing space 155 inside the paper discharge table 150. The reversing space 155 includes a movable tray unit 151, a casing unit 153, a front plate 152, and a lower guide member 156 that constitute the paper discharge table 150. Surrounded by

  The casing part 153 is a box having a substantially triangular side wall 153b, and is provided with a mechanism that moves the movable tray part 151 up and down in a tilted state at the top. The movable tray 151 is a cradle for the recording medium discharged from the paper discharge path DR, and is supported so as to be movable relative to the side wall 153b of the casing 153 in the vertical direction.

  In addition, a lower guide member 156 that forms a reversing portion SR2 is disposed inside the casing portion 153 below the movable tray portion 151. In the present embodiment, the lower guide member 156 is composed of two members having different operations, namely, a fulcrum side member 156b and a terminal side member 156a as shown in FIG. The recording medium is guided while being supported from below and is swung up and down with the forward end side of the reversing portion SR2 as a free end.

  The fulcrum side member 156b is a guide member that supports the recording medium that has been transported in the vicinity of the transport mechanism of the reversing unit SR2 (on the side of entering the reversing unit SR2), and the vicinity of the transport mechanism is pivotally supported by the shaft portion 156d. It swings up and down. On the other hand, the end side member 156a is a guide member that supports the recording medium conveyed to the forward end side of the reversing unit SR2 from below, and moves up and down in response to the swing of the fulcrum side member 156b. Yes. In this embodiment, the terminal member 156a is a box having a substantially trapezoidal cross section, and has an inclined surface 156f on the fulcrum member 156b side. The free end side of the fulcrum side member 156b is placed on the inclined surface 156f of the termination side member 156a, and the free end of the fulcrum side member 156b moves on the inclined surface 156f as the termination side member 156a moves up and down. Follows while sliding and swings.

  The tray driving unit 157 is provided on the side portion of the casing unit 153, and is a driving device that moves the movable tray unit 151 up and down, and moves the end side member 156a up and down in order to secure a space where the recording medium is reversed. . Specifically, the tray driving unit 157 includes a driving unit 157c provided on one side of the casing unit 153 as shown in FIG. 4 and a driven unit provided on the other side as shown in FIG. The driving portion 157c and the driven portion 157b are connected so as to sandwich the casing portion 153 from both sides by a connecting shaft 157a. The connecting shaft 157a is penetrated through the casing portion 153 so as to be movable up and down, and between the drive portion 157c and the driven portion 157b, both side walls 151b of the movable tray portion 151 and the end of the lower guide member 156 A side member 156a is connected. Then, by moving the connecting shaft 157a up and down by the drive unit 157c, the movable tray unit 151 and the terminal side member 156a move up and down in conjunction with each other.

  In the reversal space 155, the recording medium is reciprocated by the forward rotation operation and the reversal operation of the transport roller 154. In the inversion space 155, an opening portion 153a in which the front surface of the casing portion 153 is opened serves as a take-out port for the recording medium retained due to a jam or the like. On the front side of the casing portion 153, as shown in FIG. 3, the lower portion of the opening 153a is blocked by the front plate 152, and the front surface 156e of the terminal member 156a is also blocked. As a result, the front surface of the casing portion 153 is blocked by the front surface portion other than the opening 153a so that the user cannot put a hand or the like into the drive portion by the tray drive portion 157.

  As shown in FIG. 5B, a paper discharge port 140 through which the recording medium is discharged is located above the inversion space 155. Therefore, a movable tray 151 for stacking the recording medium discharged from the paper discharge port 140 is arranged between the paper discharge port 140 and the reversing space 155, and changes depending on the vertical movement of the paper discharge table 150. The space and the space for reciprocation of the recording medium are shared.

  With these configurations, in the present embodiment, the lower guide member 156 is swung following the up-and-down movement of the movable tray 151 by the offset function. FIG. 8 is an explanatory diagram showing the operation of the paper discharge tray 150 and the lower guide member 156 from the side.

  FIG. 8A shows a case where no recording medium is loaded on the paper discharge tray 150, and the paper discharge tray 150 is moved upward in order to maintain the distance d from the paper discharge outlet 140. In this case, the lower guide member 156 is also swung upward together with the movable tray portion 151, and the reversing space 155 for the reversing portion SR2 is maintained in a constant space.

  More specifically, as the movable tray portion 151 moves upward, it moves above the terminal member 156a. Thereby, the inversion space 155 is secured, and the reversing unit SR2 is also secured. Further, following the upward movement of the end side member 156a, the fulcrum side member 156b is swung upward with the end point on the transport mechanism side as an axis, and thereby, in a fan-shaped range with the end point on the transport mechanism side. A space for the inversion path is secured.

  Then, as shown in FIG. 8B, when the printing process of the recording medium proceeds and the recording medium is stacked on the movable tray unit 151, the distance d from the upper surface of the movable tray unit 151 to the paper discharge port 140 is set. In order to keep it, the movable tray 151 is lowered. At this time, the lower guide member is swung downward to secure the inversion space 155. Specifically, the trailing end member 156a moves downward following the lowering of the movable tray 151, and further following this, the fulcrum side member 156b swings downward about the end point on the transport mechanism side. To do.

(Action / Effect)
According to the present embodiment, the movable tray 151 is moved up and down according to the stacking amount of the recording medium so that the distance from the upper surface of the stacked recording medium to the paper discharge port 140 is constant. Therefore, the distance when the discharged recording medium falls to the upper surface of the recording medium loaded on the cradle can be kept constant. Thereby, for example, in the offset paper discharge, it is possible to make the air resistance received when the discharged recording medium falls, avoiding the displacement of the recording medium fall point due to variations in air resistance, Recording media can be matched. As a result, it is possible to sort and stack the discharged recording media while securing the reversing portion SR2 for double-sided printing, and to reduce the burden of sorting work by the user.

  At this time, in this embodiment, the movable tray portion 151 is disposed between the discharge port 140 and the reversing space 155, and the lower guide member 156 swings following the vertical movement of the discharge table 150. The space required for the vertical movement of the paper table 150 and the reversing space 155 can be shared, and the extra space can be eliminated while securing the reversing portion SR2, and the printing apparatus can be downsized.

  That is, in the reversing portion SR2, the lower guide member 156 can swing up and down with the outward end side as a free end, so that when the space for reversing the recording medium changes, the lower guide member 156 is allowed to follow this. Thus, the reversing part SR2 can also be deformed. As a result, the reversing unit SR2 can be secured even when the offset paper discharge function is added.

  In particular, in this embodiment, the fulcrum side member 156b swings up and down around the end point on the transport mechanism side as an axis, so that the space of the reversing portion SR2 can be secured in a fan-shaped range with the end point on the transport mechanism side. it can. Therefore, the reversing path can be deformed by following the operation of the offset function while fixing the transport function itself in the reversing unit SR2. On the other hand, since the end side member 156a can be configured to move up and down, the configuration can be simplified when a mechanism for following up and down movement such as an offset function is required.

(Example of change)
In the above-described embodiment, the reversal space 155 is used as a space for reversing the recording medium, and when a jam occurs in the reversing unit SR2, the recording medium is taken out from the opening 153a. This inversion space 155 may be used for discharging and accumulating the recording medium.

  More specifically, as shown in FIG. 9A, the recording medium is discharged and accumulated on the lower guide member 156 in the vicinity of the forward path end by the forward rotation operation of the transport roller 154 in the reversing unit SR2. When the recording medium is discharged, the forward rotation operation of the transport roller 154 is continued so that the recording medium passes through the transport roller 154, leaves the transport roller 154, and is sent to the end of the forward path in the reversing space 155. As shown in FIG. 5B, the fed sheet falls in the reversal space 155 and is received by the lower guide member 156. A stopper 156c protrudes from the end of the lower guide member 156 on the apparatus side so that the paper dropped on the lower guide member 156 does not move downward.

  According to such a modified example, when a jam occurs in the transport route other than the reverse route SR, such as when the transport on the normal route CR and the reverse route SR proceeds simultaneously by the scheduling described above, The staying recording medium can be discharged to the inversion space 155. As a result, it is possible to simplify or diversify the recovery process after the jam occurs.

It is a figure which shows the outline | summary of the printing paper conveyance path | route of the printing apparatus which concerns on embodiment. It is the figure which showed typically the paper-feeding system conveyance path which concerns on embodiment, a normal path | route, and the inversion path | route. It is an external view which shows the paper discharge stand corresponding to the offset paper discharge function which concerns on embodiment. It is an external view which shows the paper discharge stand corresponding to the offset paper discharge function which concerns on embodiment. (A) is sectional drawing which shows the internal structure of the paper discharge stand which concerns on embodiment from the side, (b) is explanatory drawing which represented typically the operation | movement of the inversion mechanism. It is explanatory drawing which represented typically the shift operation | movement of the offset function which concerns on embodiment. It is explanatory drawing which represented the elevator operation | movement of the offset function which concerns on embodiment typically. It is explanatory drawing which shows operation | movement of the paper discharge stand and lower guide member which concern on embodiment from a side surface. It is explanatory drawing which represented typically the paper discharge operation | movement in the inversion space which concerns on the example of a change.

Explanation of symbols

CR ... Normal route DR ... Discharge route FR ... Paper feed route R ... Registration SR SR ... Reverse route 10 ... Recording medium 10a ... Recording medium upper surface 100 ... Printing device 110 ... Head unit 120 ... Side feed tray 130 ... Feed tray DESCRIPTION OF SYMBOLS 140 ... Paper discharge port 141 ... Ejection roller 150 ... Paper discharge stand 151 ... Movable tray part 151a ... Upper surface 151b ... Both sides wall 152 ... Front plate 153 ... Casing part 153a ... Opening part 153b ... Side wall 154 ... Conveyance roller 155 ... Reverse space 156... Lower guide member 156 a. Terminal side member 156 b .. fulcrum side member 156 c... Stopper 156 d .. shaft portion 156 e .. front surface 156 f .. inclined surface 157 .. tray drive unit 157 a .. connection shaft 160 ... transport belt 161. 170, 172 ... switching mechanism 220 ... side Paper drive unit

Claims (2)

In a printing apparatus for forming an image on the surface of a recording medium conveyed on a conveying path, a conveying mechanism for conveying the recording medium,
The transport path is
A normal path from the paper feed path for supplying the recording medium to the paper discharge path via the image forming unit;
The recording medium is branched and connected to the normal path, the recording medium is delivered from the normal path, and the recording medium is moved back and forth by rotating the conveyance mechanism forward and backward to return to the normal path. An inversion path to invert,
The reverse path has a lower guide member that supports the recording medium from below,
The lower guide member can swing up and down with the forward end side of the forward rotation as a free end ,
The lower guide member is
A fulcrum-side member that is pivotally supported so as to swing up and down in the vicinity of the transport mechanism of the reversing path;
In response to the swing of the fulcrum member, possess a terminating member for vertical movement,
A paper discharge outlet through which the recording medium is discharged at the end of the paper discharge path is located above a space required for the reciprocation of the recording medium,
Between the discharge port and the space required for the reciprocation, a cradle for loading the recording medium discharged from the discharge port is provided to be movable up and down.
The rocking of the lower guide member, the conveying mechanism of the printing device you said to follow the vertical movement of the cradle. The cradle from the upper surface of the loaded said recording medium, so that the distance to said sheet discharge port is constant claim 1, characterized in that it is vertically moved in accordance with the load capacity of the recording medium The conveyance mechanism of the printing apparatus as described in 2.