Printing machine

Abstract

A printing machine is capable of printing a viscous fluid on an object using a screen mask, and is provided with a pair of first conveyance surfaces and a pair of second conveyance surfaces, and a plurality of types of replacement members including the screen mask are conveyed and replaced. The pair of first transport surfaces extends in a horizontal direction and transports a screen mask. The pair of second conveyance surfaces extends parallel to the extending direction of the pair of first conveyance surfaces, and conveys a conveyance jig to which another replacement member different from the screen mask is attached.

Description

Technical Field

[0001] This specification discloses a printing press. Background Art

[0002] Conventionally, a structure for automatically replacing a replacement part used in a printing press that prints a viscous fluid on an object has been known. For example, in Patent Document 1, a structure including a storage device is disclosed. The storage device stores a replaceable part including a screen mask, and the replaceable part is carried in and out between the storage device and the printing press in a state of being disposed in front of the printing press. The storage device has: a storage unit capable of storing a screen mask and a handling jig on which other replaceable parts (a squeegee, a substrate support member) are mounted; and a handling conveyor that carries the parts stored in the storage unit back and forth. The printing press has a pair of left and right handling rails that extend in the front-rear direction and are disposed between a printing processing unit and a substrate fixing unit. The printing press retracts the screen mask from the handling rail, or replaces the replaceable part by introducing the handling jig using the handling rail, or introduces the screen mask and holds it on the handling rail.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2018 / 105016 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the above printing press, when the screen mask and the handling jig move between the printing press and the storage device, the outer frames of the screen mask and the handling jig rub against the frame receiving portion of the handling rail and wear, generating wear powder. When wear powder is generated on the handling rail, the handling friction increases due to the wear powder, and it may interfere with the handling of the screen mask and the handling jig. In addition, if the wear powder accumulates due to long-term use, the screen mask may come into contact with the accumulated wear powder, which may also reduce the flatness of the screen mask.

[0008] The main object of the present disclosure is to provide a printing press that can smoothly handle a handling jig on which a screen mask and a replacement part are mounted regardless of long-term use.

[0009] Means for Solving the Problems

[0010] The present disclosure employs the following means to achieve the above main object.

[0011] The printing machine of the present disclosure can print a viscous fluid onto an object using a screen mask and carry a variety of replacement parts including the screen mask for replacement. The gist of the printing machine is to include: a pair of first carrying surfaces that extend in the horizontal direction for carrying the screen mask; and a second carrying surface that extends parallel to the extending direction of the pair of first carrying surfaces for carrying a carrying jig on which other replacement parts different from the screen mask are mounted.

[0012] In the printing machine of the present disclosure, different carrying surfaces (the first carrying surface, the second carrying surface) are respectively used in the carrying of the screen mask and the carrying of other replacement parts different from the screen mask. By dispersing the carrying surfaces, the generation of wear powder can be reduced. As a result, when replacing the screen mask and other replacement parts, regardless of years of use, the carrying of the carrying jig on which the screen mask and the replacement parts are mounted can be carried out smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a perspective view of the printing machine and the housing bracket.

[0014] Figure 2 is a side view of the printing machine and the housing bracket.

[0015] Figure 3 is a perspective view of the housing bracket, the replacement frame, and the carrying rail.

[0016] Figure 4 is a perspective view of the substrate support member and the replacement frame.

[0017] Figure 5 is an explanatory diagram showing the traveling surface of the replacement frame of the screen mask.

[0018] Figure 6 is an explanatory diagram showing the traveling surface of the replacement frame of the substrate support member. DETAILED DESCRIPTION

[0019] Next, a mode for implementing the present disclosure will be described with reference to the drawings.

[0020] Figure 1 is a perspective view of the printing machine 10 and the housing bracket 60. Figure 2 is a side view of the printing machine 10 and the housing bracket 60. Figure 3 is a perspective view of the housing bracket 60, the replacement frame 80, and the carrying rail 40. Figure 4 is a perspective view of the substrate support member 32 and the replacement frame 80. In Figures 1 to 3 the left - right direction is set as the X - axis, the front - rear direction is set as the Y - axis, and the up - down direction is set as the Z - axis.

[0021] The printing machine 10 of the present embodiment prints solder paste onto the substrate S below through the pattern holes formed in the screen mask M by pressing the solder paste on the screen mask M using the squeegee 22. The printing machine 10 is combined with a component mounter that mounts electronic components on the substrate S printed with solder to form a production line. Moreover, when changing the type of the substrate S to be produced, the printing machine 10 can automatically replace the screen mask M and the substrate support member 32 that supports the substrate S according to the type of the substrate S.

[0022] As Figure 1 , Figure 2 shown, the printing machine 10 includes a printing machine main body 11, a housing 12 that houses the printing machine main body 11, a replacement device 50, a housing bracket 60, and a control device (not shown) that controls the entire printing machine. The printing machine main body 11 has a head device 20, a substrate transfer device 30, an identification unit 35, and a transfer rail 40.

[0023] The head device 20 is provided at the upper stage portion of the printing machine main body 11. As Figure 1 shown, the head device 20 includes a head main body 21 and a head moving portion 26 that moves the head main body 21 in the front-rear direction (Y-axis direction) as the printing direction. The head moving portion 26 has a guide rail 28 extending in the front-rear direction, a Y-axis slider 27 that moves along the guide rail 28, and a motor (not shown) that drives the Y-axis slider 27. As Figure 2 shown, the head main body 21 has: a pair of front and rear squeegees 22; a squeegee lifting portion 23 formed of, for example, a cylinder and lifting the corresponding squeegee 22; a pusher 24; and a pusher lifting portion 25 formed of, for example, a cylinder and lifting the pusher 24. The pair of squeegees 22 are plate-like members extending in the left-right direction (X-axis direction) orthogonal to the printing direction, and are inclined so as to separate from each other as they face downward when viewed from the left-right direction. A pair of transfer rails 40 extending in the front-rear direction are provided at the middle stage portion of the printing machine main body 11. In a state where the pusher 24 is lowered by the pusher lifting portion 25, the pusher 24 moves back and forth through the head moving portion 26, thereby pressing the replacement frames 70, 80 on the transfer rail 40 back and forth to move them. Figure 2 shown, the replacement frames 70, 80 move in and out of the housing 12 through a through hole 36 provided at the middle stage portion of the front surface of the housing 12. In addition, a detection sensor 37 for detecting the passage of the replacement frames 70, 80 is provided at the through hole 36.

[0024] The substrate transfer device 30 is provided at the lower stage portion of the printing machine main body 11. The substrate transfer device 30 loads and positions the support substrate S, and brings the substrate S into contact with and separates it from the screen mask M (back surface). Figure 2As shown, the substrate transfer device 30 includes: a substrate transfer unit 31 that transfers a substrate S in the left-right direction (X-axis direction); a substrate support member 32 as a support member that supports the substrate S from below; and a substrate support member lifting unit 33 that lifts and lowers the substrate support member 32. The substrate support member 32 is replaced with a member having a size suitable for supporting the substrate S according to the type of the substrate S.

[0025] An identification unit 35 identifies the substrate S and the substrate support member 32. The identification unit 35 reads a mark attached to the upper surface of the substrate S transferred and positioned by the substrate transfer device 30 to identify the position of the substrate S, or reads a mark attached to the bottom surface of the substrate support member 32 of the replacement frame 80 supported on the transfer rail 40 to identify the position and size of the substrate support member 32.

[0026] The replacement device 50 uses the replacement frames 70 and 80 to receive the storage bracket 60 that houses the replacement parts (screen mask M, substrate support member 32) used in the printing machine main body 11, and transfers the replacement parts between the storage bracket 60 and the printing machine main body 11. The replacement device 50 includes a left unit 51a provided on the left side of the front surface of the printing machine main body 11 and a right unit 51b provided on the right side of the front surface of the printing machine main body 11. The left unit 51a and the right unit 51b have a bracket support member 52 that receives the storage bracket 60 and supports its lower surface from both left and right sides, and a bracket lifting unit 53 that lifts and lowers the bracket support member 52. The bracket lifting unit 53 is constituted by, for example, a combination of a ball screw mechanism and a motor, or a linear motor. The storage bracket 60 supported by the bracket support member 52 is lifted and lowered together with the bracket support member 52. Further, the left unit 51a and the right unit 51b have a frame forward-backward movement unit 54 that conveys the replacement frames 70 and 80 in the storage bracket 60 forward and backward from both left and right sides using a belt, rollers, etc.

[0027] As Figure 1As shown, the accommodation bracket 60 is an accommodation body that has multiple pairs of left and right support rails 61 on the upper and lower sides and can accommodate replacement parts in each support rail 61. In addition, opening portions 62 and 63 are formed on the front surface and the back surface of the printing press main body 11 of the accommodation bracket 60. The replacement parts are taken out and put in by an operator or the like through the opening portion 62 on the front surface side, and are carried in and out through the opening portion 63 on the back surface side by the frame front and back moving portion 54. In a state where the accommodation bracket 60 is accommodated in the replacement device 50, the frame front and back moving portion 54 sends the replacement parts on the support rail 61 of the multiple support rails 61 supported by the accommodation bracket 60, which is located at substantially the same height as the transfer rail 40 of the printing press main body 11 by the bracket lifting portion 53, to the printing press main body 11. In addition, the frame front and back moving portion 54 sends the replacement parts supported by the transfer rail 40 of the printing press main body 11 into the support rail 61 of the accommodation bracket 60 located at substantially the same height as the transfer rail 40. In addition, the accommodation bracket 60 can be carried by an operator to the receiving position of the replacement device 50, or can be mounted on an automatic guided vehicle (AGV) and automatically carried by the automatic guided vehicle to the receiving position of the replacement device 50.

[0028] The replacement frame 70 is a frame that supports the screen mask M. The screen mask M is a thin metal plate and is supported by the replacement frame 70 in a state where a predetermined tension is applied. The screen mask M is positioned and fixed in the working area on the transfer rail 40 while being supported by the replacement frame 70 and is used for printing.

[0029] As Figure 4 shown, the replacement frame 80 is a frame that supports the substrate support member 32 and has substantially the same left and right width as the replacement frame 70. The replacement frame 80 includes a rectangular outer frame 81, a pair of support portions 82 and cam followers 83 that are fixed to the outer frame 81 in a facing manner and support the substrate support member 32 from both sides. A plurality (for example, four) of cam followers 83 are rotatably supported on the inner side and the lower surface of the left side portion 81a and the right side portion 81b of the outer frame 81, respectively.

[0030] As Figure 2 、 Figure 3 shown, the transfer rail 40 is provided at substantially the same height as the through port 36 (refer to Figure 2 ) in the middle section of the printing press main body 11 and is a pair of long rails extending in the front and back direction (Y-axis direction). The transfer rail 40 has a pair of left and right first transfer surfaces 41 for transferring the replacement frame 70 (screen mask M) and a pair of left and right second transfer surfaces 45 for transferring the replacement frame 80 (substrate support member 32).

[0031] On each of a pair of left and right first transfer surfaces 41, there are provided: a flat transfer surface main body 42 extending in the front-rear direction; and a plurality of support portions 43, which are provided at a predetermined interval in the front-rear direction with respect to the transfer surface main body 42 and protrude upward from the transfer surface main body 42. That is, each first transfer surface 41 has steps due to the respective support portions 43. As Figure 5 shown, each support portion 43 has a contact surface that contacts the lower surface of the replacement frame 70 (outer frame) of the screen mask M, and the screen mask M is supported in a horizontal posture by this contact surface. The contact surface of the support portion 43 ensures good flatness accuracy and height accuracy through machining such as cutting. Thus, compared with the case where the replacement frame 70 (outer frame) is supported by the transfer surface main body 42, it is possible to more easily ensure the flatness of the screen mask M. In addition, a circumferential groove 44 that is recessed from the transfer surface main body 42 is formed around the support portion 43. Therefore, it is possible to receive the wear powder generated when the replacement frame 70 supporting the screen mask M slides on the support portion 43 by using the groove 44, and it is possible to suppress the adhesion of the wear powder to the transfer surface main body 42 and the support portion 43.

[0032] A pair of left and right second transfer surfaces 45 are respectively provided continuously with the inner sides of the pair of left and right first transfer surfaces 41. As Figure 6 shown, each second transfer surface 45 is formed by a flat surface without steps extending in the front-rear direction at a position one step lower than the outer first transfer surface 41 (transfer surface main body 42). As described above, cam followers 83 are provided on the inner sides and lower surfaces of the left and right side portions 81a and 81b of the outer frame 81 of the replacement frame 80, and the replacement frame 80 travels along the transfer track 40 by rolling the cam followers 83 on the second transfer surface 45. As Figure 6 shown, the pair of left and right first transfer surfaces 41 (support portions 43) are formed to be located at a position lower than the lower surface of the outer frame 81 of the replacement frame 80 in a state where the cam followers 83 are in contact with the second transfer surface 45. Thus, the replacement frame 80 can be smoothly transferred.

[0033] In addition, side walls 46 are provided at the inner ends of the pair of left and right second transfer surfaces 45 facing each other. The side walls 46 mainly serve to prevent the wear powder generated during the transfer of the replacement frame 80 (substrate support member 32) on the second transfer surface 45 from falling onto the substrate S, the substrate transfer device 30, etc.

[0034] Here, the replacement of the screen mask M is performed as follows. That is, the control device of the printing machine 10 first controls the pusher lifting part 25 and the head moving part 26, and uses the pusher 24 to push the replacement frame 70 supported on the first carrying surface 41 of the screen mask M to move it on the first carrying surface 41, and carry out the replacement frame 70 from the through port 36 to the outside of the housing 12. Next, the control device controls the replacement device 50 to recycle the replacement bracket 70 to the receiving bracket 60. Then, the control device controls the replacement device 50 to take out the replacement frame 70 supporting the new screen mask M from the receiving bracket 60 and carry it into the housing 12 from the through port 36. Then, the control device controls the pusher lifting part 25 and the head moving part 26, and uses the pusher 24 to push the carried-in replacement frame 70 to move it on the first carrying surface 41, thereby carrying the replacement frame 70 (new screen mask M) to the working area and positioning it.

[0035] In addition, the substrate support member 32 is also replaced as needed. The replacement of the substrate support member 32 is performed in a state where the screen mask M (replacement frame 70) on the transport rail 40 is retreated to the storage rack 60. The control device of the printing machine 10 controls the replacement device 50 to take out the empty replacement frame 80 from the storage rack 60 and move it into the housing 12 from the through port 36. Next, the control device controls the pusher lifting unit 25 and the head moving unit 26 to push the empty replacement frame 80 moved into the housing 12 by the pusher 24 to move it on the second transport surface 45, thereby moving the replacement frame 80 to the working area. Next, the control device controls the substrate support member lifting unit 33 to raise the substrate support member 32 and hand over the substrate support member 32 to the replacement frame 80 on the second transport surface 45. In addition, regarding the handover of the substrate support member 32, for example, the method described in International Publication No. 2018 / 105016 can be used. Next, the control device controls the pusher lifting unit 25 and the head moving unit 26, and uses the pusher 24 to push the replacement frame 80 to move it on the second conveying surface 45, and carries the replacement frame 80 out of the housing 12 from the through port 36. Then, the control device controls the replacement device 50 to recover the replacement frame 80 to the storage rack 60. Next, the control device controls the replacement device 50 to take out the replacement frame 80 supporting the new substrate support member 32 from the storage rack 60, and carry it into the housing 12 from the through port 36. Next, the control device controls the pusher lifting unit 25 and the head moving unit 26, and uses the pusher 24 to push the replacement frame 80 carried into the housing 12 to move it on the second conveying surface 45, thereby carrying the replacement frame 80 (new substrate support member 32) to the work area. Then, the control device controls the substrate support member lifting unit 33 to raise the substrate support member 32, and deliver the new substrate support member 32 to the substrate support member lifting unit 33. After that, the control device controls the pusher lifting unit 25 and the head moving unit 26, and uses the pusher 24 to push the empty replacement frame 80 after the substrate support member 32 is delivered to move it on the second conveying surface 45, and outputs the replacement frame 80 from the through port 36 to the outside of the housing 12. Then, the control device controls the replacement device 50 to recover the empty replacement frame 80 to the storage rack 60.

[0036] Thus, in the present embodiment, the screen mask M and the substrate support member 32 are transported using different transport surfaces (the first transport surface 41 and the second transport surface 45), respectively. Therefore, the transport surfaces can be dispersed, and the generation of abrasive powder can be reduced. Further, when replacing the screen mask M, even if abrasive powder is generated due to the sliding of the replacement frame 70 and the support portions 43 of the pair of left and right first transport surfaces 41, the generated abrasive powder accumulates in the grooves 44 formed around the respective support portions 43. Therefore, it is possible to suppress the attachment and accumulation of abrasive powder on the transport surface main body 42 and the support portions 43, and to prevent the replacement frame 70 from coming into contact with the accumulated abrasive powder and reducing the flatness of the screen mask M. In addition, the replacement frame 80 of the substrate support member 32 is transported by rolling on the pair of left and right second transport surfaces 45 via the cam followers 83, so that the replacement frame 80 can be transported smoothly. Further, the pair of left and right second transport surfaces 45 are provided at a position lower than the first transport surface 41 inside the pair of left and right first transport surfaces 41. Therefore, even if abrasive powder is generated on the second transport surface 45 as the replacement frame 80 is transported, it is possible to suppress the attachment of the abrasive powder to the first transport surface 41. In addition, since side walls 46 are provided at the inner ends of the pair of left and right second transport surfaces 45 facing each other, even if abrasive powder is generated on the second transport surface 45 as the replacement frame 80 is transported, it is possible to prevent the generated abrasive powder from falling onto the substrate transport device 30 and the substrate S.

[0037] Here, the correspondence between the main elements of the embodiment and the main elements of the present disclosure described in the claims will be described. That is, the screen mask M and the substrate support member 32 of the present embodiment correspond to the replacement members of the present disclosure, the printing machine 10 corresponds to the printing machine, the first transport surface 41 corresponds to the first transport surface, the replacement frame 80 corresponds to the transport jig, and the second transport surface 45 corresponds to the second transport surface. In addition, the transport surface main body 42 corresponds to the transport surface main body, and the support portions 43 correspond to the support portions. In addition, the groove 44 corresponds to the recess. In addition, the cam followers 83 correspond to the cam followers. In addition, the side walls 46 correspond to the side walls.

[0038] In addition, the present disclosure is not limited to any of the above embodiments, and can of course be implemented in various ways as long as it belongs to the technical scope of the present disclosure.

[0039] For example, in the above embodiment, the replacement frame 80 is transported by rolling on the second transport surface 45 via the cam followers 83 provided on its outer frame 81. However, the cam followers 83 may be omitted, and the replacement frame 80 may be transported by sliding on the second transport surface 45.

[0040] In the above embodiment, the pair of left and right second transport surfaces 45 are provided inside the pair of left and right first transport surfaces 41, but they may also be provided outside the pair of left and right first transport surfaces 41.

[0041] In the above-described embodiment, the second transfer surface 45 is used to transfer the replacement frame 80 on which the substrate support member 32 is mounted. However, the second transfer surface 45 may be used as long as it is used in the printing machine 10, and may also be used to transfer a replacement frame (transfer jig) on which a replacement member other than the screen mask M (for example, the squeegee 22) is mounted. In addition, regarding the transfer of the squeegee 22 as a replacement member to the head main body 21 when the squeegee 22 is mounted on the replacement frame and transferred on the second transfer surface 45, for example, the method described in International Publication No. 2018 / 105016 can be used.

[0042] In the above-described embodiment, the printing machine of the present disclosure is applied to a printing machine that prints solder as a viscous fluid on a substrate S as an object. However, as the object, other substrates such as three-dimensional objects may be used, and as the viscous fluid, conductive paste, adhesive, etc. may be used.

[0043] As described above, in the printing machine of the present disclosure, different transfer surfaces (first transfer surface, second transfer surface) are used for the transfer of the screen mask and the transfer of other replacement members different from the screen mask. By dispersing the transfer surfaces, the generation of wear powder can be reduced. As a result, when replacing the screen mask and other replacement members, the transfer of the transfer jig on which the screen mask and the replacement member are mounted can be smoothly performed regardless of the years of use.

[0044] In such a printing machine of the present disclosure, the pair of first transfer surfaces may have steps, and the pair of second transfer surfaces may not have steps. In this way, the transfer of the transfer jig on the second transfer surface can be smoothly performed. In this case, the pair of first transfer surfaces may have: a transfer surface main body; and a support portion that bulges to a position higher than the transfer surface main body as the step and supports the screen mask in a horizontal posture. In this way, by ensuring the accuracy of the support portion, the flatness of the screen mask can be well maintained without ensuring the accuracy of the entire first transfer surface. Moreover, in this case, the first transfer surface may have a concave portion that is recessed from the transfer surface main body around the support portion. The wear powder generated when the screen mask is transferred using the first transfer surface can be received by the concave portion.

[0045] In addition, in the printing machine of the present disclosure, the pair of second transfer surfaces may be provided at a position lower than the pair of first transfer surfaces. In this way, it is possible to suppress the wear powder generated when the transfer jig is transferred using the second transfer surface from adhering to the first transfer surface for transferring the screen mask.

[0046] In addition, in the printing machine of the present disclosure, it may also be that a cam follower that rolls on the second transfer surface is provided on the transfer jig, and the pair of first transfer surfaces are provided at positions lower than the bottom surface of the frame of the transfer jig in a state where the cam follower is in contact with the second transfer surface. In this way, the transfer of the transfer jig can be carried out smoothly.

[0047] In addition, in the printing machine of the present disclosure, it may also be that the pair of second transfer surfaces are continuously provided inside the pair of first transfer surfaces, and side walls are provided at the ends of the pair of second transfer surfaces on the opposite sides of each other. In this way, it is possible to prevent the wear powder generated when the transfer jig is transferred using the second transfer surface from falling.

[0048] In this specification, the technical idea of changing "the printing machine according to any one of Technical Solutions 1 to 4" to "the printing machine according to any one of Technical Solutions 1 to 5" in the original technical solution 6 of the application and the technical idea of changing "the printing machine according to any one of Technical Solutions 1 to 4" to "the printing machine according to any one of Technical Solutions 1 to 6" in the original technical solution 7 of the application are also disclosed.

[0049] Industrial Applicability

[0050] The present disclosure can be used in the manufacturing industry of printing machines and the like.

[0051] Explanation of Reference Numerals

[0052] 10 Printing machine, 11 Printing machine main body, 12 Housing, 20 Head device, 21 Head main body, 22 Blade, 23 Blade lifting part, 24 Pusher, 25 Pusher lifting part, 26 Head moving part, 27 Y-axis slider, 28 Guide rail, 30 Substrate transfer device, 31 Substrate transfer part, 32 Substrate support member, 33 Substrate support member lifting part, 35 Identification part, 36 Through port, 37 Detection sensor, 40 Transfer rail, 41 First transfer surface, 42 Transfer surface main body, 43 Support part, 44 Groove, 45 Second transfer surface, 46 Side wall, 50 Replacement device, 51a Left unit, 51b Right unit, 52 Bracket support member, 53 Bracket lifting part, 54 Frame front and back moving part, 60 Receiving bracket, 61 Support rail, 62, 63 Opening, 70, 80 Replacement frame, 81 Outer frame, 81a Left side part, 81b Right side part, 82 Support part, 83 Cam follower, M Screen mask, S Substrate.

Claims

1. A printing machine capable of printing a viscous fluid onto an object using a screen mask and transporting a plurality of replacement parts including the screen mask for replacement, wherein, The printing press includes: a pair of first conveying surfaces that extend in the horizontal direction and are used to convey the screen mask; and a second conveying surface that extends parallel to the extending direction of the pair of first conveying surfaces and is used to convey a conveying jig on which other replacement components different from the screen mask are mounted.

2. The printing machine according to claim 1, wherein, The pair of first conveying surfaces have steps, and the pair of second conveying surfaces do not have steps.

3. The printing machine according to claim 2, wherein, The pair of first conveying surfaces have: a conveying surface main body; and a support portion that bulges to a position higher than the conveying surface main body as the step and supports the screen mask in a horizontal posture.

4. The printing machine according to claim 3, wherein, The first conveying surface has a recessed portion that is recessed from the conveying surface main body around the support portion.

5. The printing machine according to any one of claims 1 to 4, wherein, The pair of second conveying surfaces are provided at a position lower than the pair of first conveying surfaces.

6. The printing machine according to any one of claims 1 to 4, wherein, A cam follower that rolls on the second conveying surface is provided on the conveying jig, and the pair of first conveying surfaces are provided at a position lower than the bottom surface of the frame of the conveying jig in a state where the cam follower is in contact with the second conveying surface.

7. The printing machine according to any one of claims 1 to 4, wherein, The pair of second conveying surfaces are continuously provided inside the pair of first conveying surfaces, and side walls are provided at the ends of the pair of second conveying surfaces on the opposite sides of each other.

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