JP5193812B2 - Feed mechanism of printing device - Google Patents

Description

  The present invention relates to a paper feed mechanism that supplies a recording medium in a printing apparatus that forms an image on a recording medium conveyed on a conveyance path by an image forming unit.

  2. Description of the Related Art Conventionally, in a printing apparatus that transports a recording medium on a transport path and prints in an image forming unit, a registration unit that corrects the inclination or bending of the recording medium when the recording medium is supplied from the paper feed path to the transport path Is provided. In the registration unit, the tip of the recording medium is temporarily abutted on the upstream side of the registration unit so that the recording medium properly enters the conveyance path, and the inclination of the recording medium is corrected.

On the upstream side of such a resist portion, the recording medium abutted against the leading end is further pushed in by a conveying force from the rear, and slackening occurs. Conventionally, in order to allow this slackness in the paper feed path, the recording medium is slackened in a slack space provided upstream in the conveyance direction of the registration unit (for example, Patent Document 1).
JP 2008-19050 A

  However, in a printing apparatus having a structure in which the paper feed path transports the recording medium from above to below, the recording medium moves along the curve of the paper feed path due to gravity. For this reason, in the technique disclosed in Patent Document 1 described above, when the recording medium is abutted against the registration roller, the slackness increases toward the outside of the curve due to the pressure and gravity from the back, and the recording medium is restored against it. Power will also be increased. As a result, when the restoring force of the recording medium becomes a certain level or more, the slack shape of the recording medium is reversed from the outside of the curve to the inside, and there is a problem that a large noise is generated.

  Therefore, the present invention has been made in view of the above points, and it is an object of the present invention to provide a transport mechanism that can reduce noise generated when a recording medium is reversed in a paper feed path in a paper feed mechanism of a printing apparatus. And

In order to solve the above problems, the present invention is a recording medium conveyed on the conveyance path, the image forming unit A sheet feeding mechanism of the printing apparatus for forming an image, the image forming section upstream of the conveyance path A registration roller that holds the recording medium for feeding and adjusts the feeding timing of the recording medium to the image forming unit, a curved feeding path from upstream of the registration roller to the registration roller, and in this feeding path A guide member that regulates conveyance of the recording medium, and the guide members are arranged to face each other, regulate the inner side and the outer side of the curved portion of the sheet feeding path, respectively, and widen toward the upstream side, and an outer member, the outer curved portion of the feed path, in and upstream of the outer member, possess a protruding member that protrudes toward the outer side of the curved portion inwardly, projecting member The extension line intersects the upstream end of the inner member, and the conveyance path is branched and connected to the normal conveyance path from the registration roller to the paper discharge path through the image forming unit, and the normal conveyance path. The recording medium is delivered from the path, and includes a reversing path for reversing the front and back of the recording medium by reciprocating the recording medium and returning it to the normal conveying path, and a refeed path from the reversing path to the normal conveying path. The paper path includes a refeed path .

According to such an invention, the recording medium is guided to the inner member and the outer member of the guide member, and is conveyed to the registration roller along the curved sheet feeding path. At this time, the projecting member installed upstream of the outer member is directed from the outside to the inside, so that the recording medium transported contacts the projecting member before the recording roller reaches the registration roller. The medium can be directed to the inside of the paper feed path. As a result of this orientation, the recording medium is abutted against the registration roller and held (nip) while having a slack that swells to the inside of the paper feed path. As a result, it is possible to avoid the occurrence of slack to the outside of the curved sheet feeding path, and it is possible to reduce the noise that occurs when the slack that bulges outward is reversed to the inside. In addition, by generating slack at an appropriate position, it is possible to reduce the occurrence of excessive slack. For example, before the recording medium is flipped inward, the recording medium is excessively slack in the upstream and other spaces. , Thereby preventing the generation of traces such as wrinkles. In addition, since the refeed path is included in the paper feed path, even in a printing apparatus having a so-called switchback function that performs double-sided printing by reversing the recording medium, there is a slack that bulges outward in the refeed path. It is possible to reduce the noise generated when turning inward and the wrinkles caused by excessive slack at an inappropriate position.

  The above invention further includes a pair of paper feed rollers for supplying the recording medium to the paper feed path, and the paper feed roller has an inner roller arranged inside the curved portion and an outer roller arranged outside. And it is preferable that the protrusion member is arrange | positioned so that the common tangent of an inner side roller and an outer side roller may cross | intersect.

  In this case, the recording medium is ejected in the common tangential direction of the inner roller and the outer roller of the paper feed roller, and the projecting member is arranged in the ejection direction of the recording medium, so that the recording medium is more reliably used as the projecting member. The recording medium can be contacted, and the recording medium can be directed to the inside of the paper feed path.

  The above invention further includes a pair of paper feed rollers for supplying the recording medium to the paper feed path, and the paper feed roller has an inner roller arranged inside the curved portion and an outer roller arranged outside. And it is preferable that the free end of the protruding member is arranged so as not to intersect the common tangent line between the inner roller and the inner member.

  In this case, after the recording medium comes into contact with the inner member and the formed slack is eliminated, the contact of the recording medium with the protruding member can be reduced, and the friction force acts on the recording medium. Can be prevented.

  As described above, according to the present invention, in a paper feeding mechanism of a printing apparatus that performs printing on a recording medium transported on a transport path such as an ink jet system, before reaching the registration roller while saving space. In addition, it is possible to form a slack that swells inward in the paper feed path in the recording medium, and to reduce noise and wrinkles that occur when the slack that swells outward in the paper feed path reverses inward. .

(Overall configuration of printing device)
Embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a diagram illustrating an outline of a conveyance path of the printing apparatus 100 according to the present embodiment. In this embodiment, the printing apparatus 100 includes a plurality of ink heads on which a large number of nozzles are formed, discharges black or color ink from each ink head, performs printing in line units, and prints on a recording medium 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. 1A, the printing apparatus 100 is an apparatus that forms an image on the surface of a recording medium conveyed on an annular conveyance path, and the conveyance path includes a paper feed path FR that supplies the recording medium, A normal path CR from the paper feed path FR to the paper discharge path DR via the head unit 110 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 a recording medium, 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). In addition, a paper discharge port 140 is provided as a paper discharge mechanism for discharging the printed recording medium.

  A recording medium fed from one of the side paper feed tray 120 and the paper feed tray 130 is conveyed along a paper feed path FR in the housing by a driving mechanism such as a roller, and the leading portion of the recording medium. 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 recording medium 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 recording medium 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 recording medium, the paper is directly discharged to the paper discharge port 140 through the paper discharge path 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 recording medium discharged from the sheet discharge port 140 is naturally arranged and overlapped by a 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 recording medium, the front surface (the first printed surface is “front surface” and the next printed surface is “back surface”). Without being guided to the side, it is further transported in the housing and sent out to the reversing 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 the recording medium that has not been sent to the discharge path by the switching mechanism 170 is drawn into the reversing path SR.

  In the reversal path SR, the recording medium is delivered from the normal path CR, and so-called switchback is performed in which the recording medium is reversed by reciprocating the recording medium. 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. Thereafter, the recording medium on which the back side is printed and images are formed on both sides is guided to the paper discharge port 140 through the paper discharge route DR and discharged, and the paper discharge is provided as a receiving base of the paper discharge port 140. 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 space provided in the paper discharge tray 150 is configured to be covered so that the recording medium cannot be removed from the outside during switchback. As a result, it is possible to prevent the user from accidentally pulling out the recording medium during the reversing operation. Further, the paper discharge tray 150 is originally provided in the printing apparatus 100, and by performing switchback using the space in the paper discharge tray 150, a separate switchback is provided in the printing apparatus 100. There is no need to provide space. 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 discharge of other recording media can be performed in parallel.

  In the printing apparatus 100, the recording medium that has been printed on one side is also re-fed to the registration portion R that is the reference position of the leading portion of the fed recording medium. For this reason, a junction point where the conveyance path of the newly fed recording medium and the refeed path where the recording medium for backside printing is circulated is merged is formed immediately before the registration portion R. Is done. Then, the registration unit R sends out the recording medium in the vicinity of the merging point between the sheet feeding 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 based on the merging point. This transport path is annular, and includes the normal path CR and the reverse path SR as described above. FIG. 1B is a diagram schematically illustrating 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. Thus, a sheet feeding unit for feeding the recording medium to the registration unit R is configured.

  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 recorded recording media are taken one by one and conveyed in the direction of the resist 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 a recording medium or the leading edge of the recording medium. 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 recording medium within a predetermined time after detecting the recording medium, it can be determined that a conveyance jam has occurred.

  Among these conveyance sensors, the registration sensor in front of the registration unit R that sends out the recording medium measures the size of the recording medium being conveyed, for example, the recording medium that is passing based on the passing speed and the passing time of the recording medium. When a conveyance sensor does not detect a recording medium within a predetermined time after measuring the size of the paper or driving the side paper feed drive unit 220, the tray 1 drive unit 230a, etc., a paper jam (paper feed error) has occurred. It can be judged.

  The normal path CR constitutes a part of the circulation conveyance path, and is a path from the paper feed path FR for supplying the recording medium to the paper discharge path DR through the head unit 110, and the upper surface of the recording medium on the normal path CR. An image is formed. The normal path CR includes a registration driving unit 240 that guides the recording medium 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. The first upper surface transport driving unit 260 and the second upper surface transport driving unit 265, which are sequentially arranged, the upper surface discharge driving unit 270 that guides the printed recording medium to the paper discharge port 140, and the recording medium is pulled into the reverse path SR for back surface printing. Driving means are provided. Each drive unit includes a drive mechanism composed of one or a plurality of rollers or the like, and conveys the recording medium 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 recording medium.

  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 recording medium is appropriately conveyed also in the resist 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 recording medium is transferred from the normal path CR, and the recording medium is reciprocated (switched back) to return to the normal path CR to reverse the front and back of the recording medium. The reversing path SR is provided with a reversing drive unit 281 and a refeed driving unit 282 for reversing the recording medium and leading it to the junction. The reversing path SR can be transported at a speed different from that of the normal path CR, and when taking over the recording medium from the normal path CR, it is accelerated or decelerated, and the stop time at the time of switchback is extended or shortened. Can be.

  In the present embodiment, after a certain recording medium is fed, the next recording medium is not fed after waiting for the recording medium to be printed and discharged. Before the recording medium is discharged, the subsequent recording medium is fed and can be continuously printed 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 recording medium returned from the reversing path SR is inserted when feeding the recording medium on the front surface. 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 wound around a driving roller 161 and a driven roller 162 disposed at the front end and the 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.

  Furthermore, as illustrated in FIG. 1A, 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.

(Paper feed mechanism)
In the present embodiment, the paper feed path FR described above includes the paper feed mechanism according to the present invention. FIG. 2 is a side view showing a schematic configuration of the paper feed mechanism according to the present embodiment.

  As shown in the figure, the paper feed mechanism is a mechanism that is provided in the above-described paper feed system conveyance path FR and sends the recording medium 10 to the registration unit R. In this embodiment, the paper feed mechanism is provided at the lower part of the apparatus main body. The paper feed path FR1 for newly feeding paper from the fed paper tray 130 (130a, 130b, 130c, 130d), and the paper feed path FR2 for newly feeding paper from the side paper feed tray 120 are reversed. A sheet feeding path FR3 for performing refeeding from the path SR is gathered at a collection point 214, and the recording medium 10 is supplied from each of the sheet feeding paths FR1 to FR3 to the registration unit R via the collection point 214.

  In the registration unit R, a registration driving unit 240 is arranged upstream of the head unit 110 in the normal path CR, and the upper and lower registration rollers 240a and 240b constituting the registration driving unit 240 are used to feed the paper feeding system conveyance path FR. The recording medium 10 entering the normal path CR from the head is temporarily held, and the feeding timing of the recording medium 10 to the head unit 110 is adjusted, and the sheet feeding system conveyance path on the upstream side of the registration rollers 240a and 240b. A junction point is located in the FR, and each path leads to the aggregation point 214 via each junction point.

  A gathering path is formed at the gathering point 214 by a pair of upper and lower guide members 210 a and 210 a so as to taper toward the downstream registration portion R, and each feeding path faces the gathering point 214. FR1 to FR3 are arranged. Further, these paper feed paths FR1 to FR3 respectively have widened portions 211, 212, and 213 that loosen the recording medium 10 for paper feed upstream of the set point.

  More specifically, the paper feed path FR1 is formed by being sandwiched between guide members 210e and 210f so as to taper toward the gathering point 214, and the recording medium 10 is sent out from below to above. The guide members 210e and 210f have a widened portion 211 formed by expanding downward. A paper feed roller 183 (see FIG. 1) is provided below the widened portion 211, and the leading end of the recording medium 10 fed upward by the paper feed roller 183 comes into contact with the registration rollers 240a and 240b. As a result, slackening occurs in the widened portion 211.

  The sheet feeding path FR2 is formed by being sandwiched between guide members 210d and 210c so as to taper toward the gathering point 214, and the recording medium 10 is sent obliquely upward. The guide members 210d and 210c A widened portion 212 is formed by expanding toward the upstream in the transport direction. A side paper feed drive unit 220 is provided further upstream of the widening portion 212, and the recording medium 10 is sent out downstream by the pickup by the side paper feed drive unit 220, and the leading ends thereof are registration rollers 240 a and 240 b. The widened portion 212 is slackened by being brought into contact with.

  The sheet feeding path FR3 is a curved sheet feeding path from the reverse path SR upstream of the registration driving unit 240 to the registration driving unit 240, and the conveyance of the recording medium 10 is regulated by the guide member. Specifically, as shown in FIG. 3, the guide member of the paper feed path FR3 is disposed opposite to the inner member 210b that regulates the inside of the curved portion of the paper feed path, and the inner member 210b. It has an outer member 210c that regulates the outer side, and an upstream member 216 that is disposed outside the curved portion of the sheet feeding path FR3 and upstream of the outer member.

  The sheet feeding path FR3 is formed by being sandwiched between the inner member 210b and the outer member 210c so as to be tapered toward the set point 214, and forms a path through which the recording medium 10 is sent obliquely downward. The widened portion 213 is formed by the member 210b and the outer member 210c expanding obliquely upward and upstream. Above the widening portion 213, a re-feed driving unit 282 of the reversing path SR is provided. By the re-feeding by the re-feed driving unit 282, the recording medium 10 is sent out downward, and the leading end thereof is a resist. By coming into contact with the rollers 240a and 240b, the widened portion 213 is slackened.

  In particular, in the present embodiment, the upstream member 216 is a bent portion 216a whose tip is bent toward the inner member. The bent portion 216a is a protruding member that protrudes from the outside to the inside of the curved portion in the path FR3, and the recording medium 10 is oriented by the bent portion 216a.

  The refeed driving unit 282 includes a pair of feed rollers upstream of the upstream member 216. The pair of paper feed rollers is a paper feed roller that supplies the recording medium 10 to the paper feed path FR3, and has an inner roller 282a arranged inside the curved portion and an outer roller 282b arranged outside. doing. The recording medium 10 is transported to the transport path FR3 by being sent out by the inner roller 282a and the outer roller 282b of the paper feed roller.

  And in this embodiment, as shown to Fig.4 (a) and (b), the bending part 216a of the upstream member 216 which is a protrusion member cross | intersects the common tangent B direction of the inner side roller 282a and the outer side roller 282b. Are arranged to be. Further, the free end of the bent portion 216a is disposed so as not to intersect the common tangent line A between the inner roller 282a and the inner member 210b.

  More specifically, if the line connecting the inner roller 282a and the free end of the upstream member 216 is an extension line C, the angle θ1 formed by the common tangent line B and the extension line C is equal to the common tangent line A and the extension line C. The bent portion 216a is disposed within the range of the angle θ1 so as to be smaller than the angle θ2 formed by.

  As a result, the recording medium 10 sends out the recording medium 10 with the common tangent line B of the inner roller 282a and the outer roller 282b as the injection direction, contacts the bent portion 216a disposed on the common tangent line B, and the feed path The direction is directed inward, and the moving direction is changed from the bent portion 216a to the inner member 210b side. Next, the recording medium 10 directed to the inside of the sheet feeding path contacts the inner member 210b to change the moving direction of the recording medium 10 to the outside of the sheet feeding path. By these two direction changes, a slack inward in the bending direction of the sheet feeding path FR3 is formed.

  As shown in FIG. 7, in the paper feed path FR of the present embodiment, the merging points C <b> 1 and C <b> 2 of the paper feed paths FR <b> 1 to FR <b> 3 do not coincide with each other upstream of the gathering point 214. A guide member 215 that regulates conveyance is provided. Specifically, the guide member 215 is a soft resin sheet-like member such as plastic or acrylic, and the sheet feed path FR1 so that the junction C1 between the sheet feed paths FR1 and FR2 is located on the most downstream side. And the downstream end of the guide member 210d that defines FR2 are attached.

  As a result, the guide member 215 protrudes between the downstream junction C1 and the adjacent upstream junction C2 so as to close the sheet feeding path FR1, and is viewed from the sheet feeding path FR1 side. The upstream side junction C2 is covered. As a result, the recording medium 10 in the paper feed path FR1 collides with the guide member 215 immediately before reaching the junction C1, and joins to the paper feed path FR2 side while pushing up the guide member 215. The point C1 is shifted downstream so that it does not coincide with the merging point C2 on the sheet feeding path FR3 side.

  By shifting the merging point with the guide member in this way, the merging points C1 and C2 between the respective paper feed paths are respectively positioned on concentric circles having a plurality of different radii R1 and R2 around the rotation axis of the registration roller 240a. It will be. As a result, the distances from the registration rollers 240a to the respective junctions C1 and C2 are ensured to be different, and the flow lines of the recording medium 10 to the registration rollers 240a and 240b are narrow before the registration rollers 240a and 240b. It will not overlap in space (aggregation point 214).

  On the other hand, in the paper feed path FR2, a plurality of recording media 10 are stacked and stored on the side paper feed stand 120, and a side paper feed drive unit 220 is provided to send out the stacked recording media 10. It has been. The side paper feed driving unit 220 includes a downstream pickup roller 220b and an upstream pickup roller 220a. The pickup rollers 220a and 220b are pivotally supported by rotating shafts 222a and 222b. The pickup roller 220b Rotational force is transmitted from the rotating shaft 222a and is driven to rotate. These pickup rollers 220 a and 220 b are rollers having a width smaller than the width of the recording medium 10, and send the uppermost recording medium 10 out of the stacked recording media 10 to the registration unit R.

  Further, in the paper feed path FR2 between the side paper feed drive unit 220 and the registration drive unit 240, when the recording medium 10 is slackened by the widening part 212, a regulating member 221 that comes into contact with the slack portion of the recording medium 10 is used. Is provided. The restriction member 221 covers the upper side of the pickup roller 220b, has a cross-sectional shape along the shape of the outer edge of the pickup roller 220b, has an arc-shaped cross section centering on the rotation shaft 222b of the pickup roller 220b, In the widened portion 212 of the paper feed path FR2, it protrudes in the direction opposite to the rotation direction (arrow direction in FIG. 2) of the pickup roller 220b. Further, the recording medium side tip 221a of the arc-shaped regulating member 221 has an increased curvature of the arc, is curved in the inner diameter direction of the arc (on the pickup roller side), and is gently in contact with the slack portion of the recording medium 10. It is like that.

  By protruding the regulating member 221 in this way, the recording medium 10 is pressed, and the recording medium 10 is restricted from moving upward in the vertical direction. In addition, since the regulating member 221 protrudes in the direction opposite to the rotation direction of the pickup roller 220b, the recording medium 10 is loosened by the rotation force of the pickup roller 220b when being conveyed to the registration roller. The regulating member 221 protrudes from the portion where the stress is concentrated in the rotation direction to disperse the stress and press the recording medium 10 to move upward in the vertical direction.

  In this embodiment, the restricting member 221 has an arc-shaped cross section and has a shape that covers the pickup roller 220b. However, the restricting member 221 may have any shape that protrudes from a portion where the node of the recording medium 10 is formed. It may be a rod member that protrudes from the knot forming portion or a shaft member that spans the entire width of the recording medium 10 so as to be parallel to the rotation shaft 222b.

  In the present embodiment, the protruding member is the bent portion 216a at the tip of the upstream member 216. However, the present invention is not limited to this, and the protruding portion 217a is provided on the outer member 217 as shown in FIG. You may make it form.

(Operation at the time of re-feeding in the paper feed mechanism)
Refeeding in the paper feed mechanism having the above-described configuration operates as follows. 5 and 6 are explanatory diagrams showing the operation of the paper feeding mechanism according to the present embodiment at the time of refeeding in time series.

  First, as shown in FIG. 5A, in the paper feeding path FR3, the recording medium 10 is ejected in the common tangential direction by the inner roller 282a and the outer roller 282b. Then, it contacts the point P1 on the bent portion 216a arranged in the ejection direction of the recording medium 10. The bent portion 216a is directed from the outside in the bending direction of the sheet feed path FR3 to the inside, and the recording medium 10 that has come into contact with the bent section 216a is directed toward the inside of the sheet feed path.

  Next, as shown in FIG. 5B, the recording medium 10 conveyed to the inside of the sheet feeding path FR3 contacts the point P2 of the inner member 210b positioned on the extension line D of the bent portion 216a. To do. As a result, the recording medium 10 is changed in the moving direction to the outside of the sheet feeding path FR3 and pushed back to the outside of the sheet feeding path FR3.

  Then, the recording medium 10 is conveyed to the outside of the paper feed path FR3, and as shown in FIG. 6A, contacts the outer member 210c at the point P3, and the registration roller along the curved paper feed path FR3. It is guided to 240a and 240b. At this time, as shown in FIG. 6A, the recording medium 10 forms a slack that swells to the inside of the paper feed path FR3. Next, as shown in FIG. 6B, the recording medium 10 is abutted against the registration rollers 240a and 240b at the point P4 and held (nip) while having a slack that swells inward of the paper feed path FR3. The After that, the registration rollers 240a and 240b are sent to the normal route CR, and the slack is eliminated with the sending. By arranging the free end of the bent portion 216a so as not to intersect the common tangent line of the inner roller 282a and the inner member 210b, the recording medium 10 can come into contact with the bent portion 216a when the slack is eliminated. Reduced.

(Action / Effect)
According to the present embodiment, the recording medium 10 can be directed to the inside of the paper feed path FR3 before reaching the registration rollers 240a and 240b in the paper feed path FR3 related to refeeding. As a result of this orientation, the recording medium 10 is abutted against the registration rollers 240a and 240b and nipped while having a slack that swells inward of the paper feed path FR3. As a result, it is possible to avoid the occurrence of the slack to the outside of the paper feed path FR3, and it is possible to reduce the noise that occurs when the slack that swells to the outside reverses to the inside. Further, by generating slack at an appropriate position, that is, a space inside the paper feed path FR3, occurrence of excessive slack is reduced. For example, before the recording medium 10 is reversed inward, the registration rollers 240a It is possible to prevent the occurrence of traces such as wrinkles due to excessive loosening at the gathering point 214 of the other.

  In this embodiment, since the inner member 210b is positioned on the extension line of the bent portion 216a, the recording medium 10 contacts the bent portion 216a and is directed to the inner side of the paper feed path, and then further on the inner side. The member 210b can be contacted. As a result, the moving direction of the recording medium 10 can be pushed back to the outside of the paper feed path, and a slack that swells to the inside of the paper feed path can be formed reliably.

  Further, since the bent portion 216a is arranged so as to intersect the common tangent line B of the inner roller 282a and the outer roller 282b, the bent portion 216a is arranged in the ejection direction of the recording medium 10, and the recording medium 10 can be more reliably brought into contact with the bent portion 216a, and the recording medium 10 can be directed to the inside of the paper feed path. Further, since the free end of the protruding member is arranged so as not to intersect the common tangent line of the inner roller 282a and the inner member 210b, the recording medium 10 contacts the inner member, and the formed slack is eliminated. Further, the contact of the recording medium 10 with the bent portion 216a can be reduced, and the frictional force can be prevented from acting on the recording medium 10.

(A) is a diagram showing an outline of a conveyance path of the printing apparatus according to the present embodiment, and (b) is a diagram schematically showing a paper feed path FR, a normal path CR, and a reverse path SR. . It is a side view which shows schematic structure of the paper feed mechanism which concerns on embodiment. It is a side view which expands and shows schematic structure of the paper feed mechanism which concerns on embodiment. It is explanatory drawing which shows the positional relationship of each member which concerns on the paper feed mechanism which concerns on embodiment. It is explanatory drawing which shows the operation | movement at the time of the refeed of the paper feed mechanism which concerns on embodiment according to a time series. It is explanatory drawing which shows the operation | movement at the time of the refeed of the paper feed mechanism which concerns on embodiment according to a time series. It is explanatory drawing which shows the positional relationship of each member which concerns on the paper feed mechanism which concerns on embodiment. It is a side view which shows schematic structure of the paper feed mechanism which concerns on the example of a change of embodiment.

Explanation of symbols

A, B ... Common tangent C, D ... Extension line C1, C2 ... Junction point CR ... Normal route DR ... Paper discharge route FR ... Paper feed route R ... Registration section SR ... Reverse route 10 ... Recording medium 100 ... Printing device 110 ... Head unit 120 ... Side paper feed tray 130 ... Paper feed tray 140 ... Discharge port 150 ... Discharge tray 160 ... Conveying belt 161 ... Drive roller 162 ... Driving roller 170,172 ... Switching mechanism 183 ... Feed roller 210a, 210d, 210e, 215 ... guide member 210b ... inner member 210c ... outer member 211, 212, 213 ... widened portion 214 ... gathering point 216 ... upstream side member 216a ... bent portion 217 ... guide member 217a ... convex portion 220 ... side paper feed drive portion 240: Registration driving unit 250: Belt driving unit 260: First upper surface conveyance driving unit 265: Second upper surface conveyance Pivot portion 270 ... top discharge drive unit 281 ... inversion driving unit 282 ... refeed driver 330 ... processing unit 340 ... control panel

Claims (3)

A paper feed mechanism of a printing apparatus that forms an image on a recording medium transported on a transport path by an image forming unit,
A registration roller that is disposed upstream of the image forming unit in the conveyance path, holds a recording medium related to the paper feed, and adjusts a sending timing of the recording medium to the image forming unit;
A curved paper feed path from the registration roller upstream to the registration roller;
A guide member that regulates conveyance of the recording medium in the paper feed path, and the guide member includes:
An inner member and an outer member that are arranged to face each other, regulate the inside and the outside of the curved portion of the sheet feeding path, and expand toward the upstream side,
Outside of the curved portion of the paper feed path, and upstream of the outer member, it possesses a protruding member that protrudes inward from the outer portion and the curved,
The extension line of the protruding member intersects the upstream end of the inner member,
The transport path is
A normal conveyance path from the registration roller to the paper discharge path through the image forming unit;
A reversing path that is branched and connected to the normal conveying path, the recording medium is transferred from the normal conveying path, and the recording medium is reciprocated to reverse the front and back of the recording medium by returning to the normal conveying path;
A refeed path from the reverse path to the normal transport path;
Including
The sheet feeding mechanism of the printing apparatus , wherein the sheet feeding path includes the refeeding path . A pair of paper feed rollers for supplying a recording medium to the paper feed path;
The paper feed roller has an inner roller arranged inside the curved portion and an outer roller arranged outside.
The sheet feeding mechanism of the printing apparatus according to claim 1, wherein the protruding member is disposed so as to intersect a common tangent line of the inner roller and the outer roller. A pair of paper feed rollers for supplying a recording medium to the paper feed path;
The paper feed roller has an inner roller arranged inside the curved portion and an outer roller arranged outside.
The paper feeding mechanism of the printing apparatus according to claim 1, wherein the free end of the protruding member is disposed so as not to intersect a common tangent line between the inner roller and the inner member.