Sheet adhesion mechanism

Abstract

The present invention provides a sheet adhesion mechanism that can adhere the sheet to the suction cylinder without causing the sheet to lift, wrinkle, or flap. [Solution] The sheet adhesion mechanism is a sheet adhesion mechanism having a front end holding part that holds the front end of the sheet, a rear end holding part that holds the rear end of the sheet, and a central holding part that holds the sheet surface of the sheet, on a cylindrical suction cylinder, wherein the central holding part has at least a first suction region and a second suction region, and is equipped with control means for controlling the suction operation of the first suction region and the second suction region, and the control means can make the timing of the first suction operation, in which suction is performed from the first suction region, and the timing of the second suction operation, in which suction is performed from the second suction region, different.

Description

Technical Field

[0001] The present invention relates to a sheet adhesion mechanism for adhering a sheet to an adsorption cylinder.

Background Art

[0002] Conventionally, for the appearance inspection of printed matter, there is an appearance inspection device that inspects printed matter (hereinafter referred to as "sheet") printed on single sheets using an inspection cylinder. This appearance inspection device includes a paper feeding unit that feeds stacked sheets one by one, a first conveying unit that conveys the sheets from the paper feeding unit to the inspection unit, an inspection unit composed of an inspection cylinder, an imaging unit, and a determination unit by an arithmetic device, a second conveying unit that conveys the sheets from the inspection unit to the paper discharging unit, and a paper discharging unit that accumulates the inspected sheets.

[0003] The inspection cylinder constituting the above-described inspection unit has a sheet adhesion mechanism that adheres the sheet conveyed from the paper feeding unit to the surface of the inspection cylinder while rotating. For example, the sheet adhesion mechanism of the inspection cylinder has a front-end holding part (for example, a gripper) that holds the front end of the sheet, a central holding part that holds the entire sheet by sucking air from a plurality of suction holes formed on the surface of the inspection cylinder by a suction pump connected to the inside of the inspection cylinder, and a rear-end holding part (for example, a gripper, suction of air) that holds the rear end of the sheet. And after the inspection cylinder and the sheet are adhered, it was common to pass through the imaging area of the imaging unit facing the inspection cylinder to obtain an image of the sheet. However, it is difficult to adhere the sheet to the surface of the inspection cylinder, and floating, wrinkles, and fluttering of the sheet occur from the surface of the inspection cylinder. As a result, since floating, wrinkles, and fluttering of the sheet are also reflected in the image obtained by the imaging unit, it has been difficult to perform a correct appearance inspection.

[0004] Therefore, the present applicant has proposed a conveying device including an inspection cylinder having a mechanism for holding the front end and the rear end of the sheet, and holding the sheet in a tensioned state on the inspection cylinder by the mechanism for holding the front end and the rear end of the sheet (for example, see Citation 1).

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Patent No. 4395587 [Overview of the project] [Problems that the invention aims to solve]

[0006] The conveying device proposed in Patent Document 1 addresses the issues of gaps between the sheet and the inspection cylinder, as well as the suppression of sheet lifting, wrinkles, and flapping. However, it has not completely solved these problems, and accurate visual inspection could not be performed.

[0007] Therefore, the present invention aims to provide a sheet adhesion mechanism that can adhere the sheet to the suction cylinder without causing the sheet to lift, wrinkle, or flap like in conventional methods. [Means for solving the problem]

[0008] The sheet adhesion mechanism of the present invention is a sheet adhesion mechanism having a front end holding part for holding the front end of the sheet, a rear end holding part for holding the rear end of the sheet, and a central holding part for holding the sheet surface of the sheet, on a cylindrical suction cylinder in a printing press, wherein the central holding part has at least a first suction region and a second suction region, and is equipped with control means for controlling the suction operation of each suction region, characterized in that the timing of the suction operation for suction from each suction region is different.

[0009] Furthermore, the control means for the sheet adhesion mechanism of the present invention is characterized in that, after the front end of the sheet is held by the front end holding part and the rear end of the sheet is held by the rear end holding part, the suction operation is controlled to be performed sequentially from the first suction area toward the suction area adjacent to the rear end holding part.

[0010] Furthermore, the rear end holding portion is characterized by having multiple rear end suction portions arranged along the axial direction of the suction cylinder, each consisting of a movable portion having at least a rear end suction hole and a fixed portion that fixes the movable portion at a predetermined position on the surface of the suction cylinder, and after the sheet is held by the rear end holding portion, the movable portion moves in a direction that tensions the sheet.

[0011] Furthermore, in the central holding portion, a first suction region and a second suction region are formed sequentially from a position close to the front end holding portion, and the control means controls the second suction operation timing to occur after the first suction operation timing.

[0012] Furthermore, the sheet adhesion mechanism of the present invention is characterized by comprising a measuring unit for measuring the adhesion state of the sheet from the suction cylinder, and a control means for controlling the suction force according to the adhesion state measured by the measuring unit. [Effects of the Invention]

[0013] According to the present invention, the central holding portion has at least a first suction region and a second suction region, and by using a control means to make the timing of a first suction operation, in which suction is performed from the first suction region, and the timing of a second suction operation, in which suction is performed from the second suction region, different, a sheet adhesion mechanism can be provided that prevents the sheet from lifting, wrinkling, and flapping. [Brief explanation of the drawing]

[0014] [Figure 1] This figure shows an example of applying a sheet adhesion mechanism according to one embodiment of the present invention to an appearance inspection device for inspecting the color density and stains of printed sheets. [Figure 2] Block diagram showing the configuration of the sheet adhesion mechanism of the present invention. [Figure 3] (a) Side view of the adsorption cylinder according to the first embodiment, (b) Surface view of the adsorption cylinder according to the first embodiment [Figure 4] (a) A diagram illustrating the behavior of the rear end holding part 12 when it holds the sheet, (b) A diagram illustrating the behavior of the rear end holding part 12 when it tensions the sheet. [Figure 5](a) Surface configuration diagram of the adsorption cylinder according to the second embodiment of the present invention, (b) Surface configuration diagram of the adsorption cylinder according to the second embodiment of the present invention [Figure 6] Side view of the sheet adhesion mechanism according to another embodiment. [Modes for carrying out the invention]

[0015] (First embodiment) Figure 1 shows an application of a sheet adhesion mechanism S according to one embodiment of the present invention to a sheet inspection device K for inspecting the color density and stains of printed sheets. The sheet inspection device K shown in Figure 1 consists of a paper feeding unit 1, an inspection unit 2, and a paper discharge unit 3. The inspection unit 2 includes a cylindrical suction cylinder (inspection cylinder in this embodiment) 10 and an inspection imaging device 5 that images the sheet 4 adsorbed on the suction cylinder 10. The inspection imaging device 5 further includes an illumination unit 5a. The inspection unit 2 also includes a paper feeding side transfer cylinder 6 and a paper discharge side transfer cylinder 7. The sheet 4 supplied from the paper feeding unit 1 by the paper feeding plate 8 is guided to the suction cylinder 10 by the paper feeding side transfer cylinder 6. The sheet 4 guided to the suction cylinder 10 is guided to the paper discharge unit 3 by the paper discharge side transfer cylinder 7. In Figure 1, the paper discharge unit 3 is shown to have one paper discharge pile on which sheets 4 determined to be good paper are loaded. However, the sheet inspection device K also has a pile for defective products (not shown) on which sheets 4 determined to be defective by the inspection unit 2 are loaded. The suction cylinder 10 shown in Figure 1 operates in a counterclockwise direction. The suction cylinder 10 also has a front end holding part 11 that holds the front end of the sheet 4, a rear end holding part 12 that holds the rear end of the sheet 4, and a central holding part 13 that holds the sheet surface of the sheet 4. This suction cylinder 10 is part of the sheet adhesion mechanism S.

[0016] Figure 2 is a block diagram of the sheet adhesion mechanism S of the present invention. The sheet adhesion mechanism S includes a suction cylinder 10 and a control means 21 that controls the behavior of the suction cylinder 10 such as suction timing and suction force. The suction cylinder 10 has a front end holding portion 11 that holds the front end of the sheet 4, a rear end holding portion 12 that holds the rear end of the sheet 4, and a central holding portion 13 that holds the sheet surface of the sheet 4. The central holding portion 13 includes a plurality of suction holes 13A formed on the surface of the suction cylinder, a suction unit 14, and a suction pump 17 installed outside the suction cylinder 10. The suction unit 14 includes an air box 15 formed inside the suction cylinder and a suction pipe 16.

[0017] Figure 3(a) is a side configuration diagram of the suction cylinder 10 shown in Figure 1, and Figure 3(b) is a surface configuration diagram of the suction cylinder 10 shown in Figure 1. In Figure 3(b), the sheet 4 is shown by a dashed line. The dotted line X-X' shown in Figure 3(b) is the center line of the width W of the suction cylinder 10 when the length of the surface of the suction cylinder 10 parallel to the axial direction S3 of the suction cylinder 10 is defined as the width W of the suction cylinder 10. In the present embodiment, the left side of the sheet 4 is referred to as 4a and the right side of the sheet 4 is referred to as 4b with the dotted line X-X' as the boundary.

[0018] The front end holding portion 11 is a gripper and holds the front end of the sheet 4 by gripping it.

[0019] The rear end holding portion 12 includes a plurality of rear end suction portions 12a arranged along the axial direction S3 of the suction cylinder 10. To explain an example of the rear end suction portion 12a, the rear end suction portion 12a includes a circular movable portion 12c having at least a rear end suction hole 12b and a fixing portion 12d that fixes the movable portion 12c at a predetermined position on the surface of the suction cylinder. The rear end suction hole 12b communicates with the suction pipe 16 as shown in Figure 3(a), and the position of the rear end suction hole 12b is adjusted when the movable portion 12c moves on the suction cylinder 10 in the direction of tensioning the sheet 4 described later.

[0020] The rear-end holding part 12 holds the rear end of the sheet 4 by air-sucking it with a plurality of rear-end suction parts 12a. After holding the sheet 4, the rear-end suction hole 12b is moved within the movable part 12c toward the first direction S1, which is the lower left outer direction of the sheet 4 shown in the left side 4a of the sheet, and the second direction S2, which is the lower right outer direction of the sheet 4 shown in the right side 4b of the sheet, to tense the sheet 4. According to this rear-end holding part 12, before the central holding part 13 adsorbs the sheet 4, the rear-end holding part 12 holds the sheet 4 and then tenses it, thereby preventing the generation of floating, wrinkles, and fluttering of the sheet 4. Details of the behavior of the rear-end suction part 12a in the rear-end holding part 12 will be described later. As described above, "tensing the sheet" in the present invention means keeping the sheet in a stretched state.

[0021] The central holding part 13 has a plurality of suction regions 13' each composed of a plurality of suction holes 13A formed on the surface of the suction cylinder 10. In an example of the present embodiment, as shown in Fig. 3(b), as the suction region 13', a first suction region 13a, a second suction region 13b, a third suction region 13c, and a fourth suction region 13d are formed. However, it is not limited to this form, and at least two suction regions 13' in the central holding part 13 may be formed. Also, a plurality of suction regions 13' can be formed according to the size of the sheet 4 and the size of the suction cylinder 10.

[0022] Furthermore, the four suction regions 13a, 13b, 13c, and 13d shown in Fig. 3(b) may have different region areas. In an example of the present embodiment, the first to fourth suction regions 13a, 13b, 13c, and 13d have the same-shaped region area (a rectangle with the side parallel to the front end of the sheet 4 being the long side in the drawing), but for example, the region areas may be different for each of the first to fourth suction regions 13a, 13b, \alpha, and 13d.

[0023] As shown in Figure 3(a), the suction cylinder 10 is equipped with a suction unit 14 consisting of an airbox 15 and a suction tube 16, which are located inside the suction cylinder 10 and correspond to the suction region 13'. The suction tube 16 is connected to a suction pump 17, which is located outside the suction cylinder 10. In one example of this embodiment, the first to fourth suction regions 13a, 13b, 13c, and 13d described above are each equipped with a corresponding suction unit 14. In other words, the shape, arrangement, and number of airboxes 15 forming the suction unit 14 are determined by the suction area, arrangement, and number of airboxes 15 in the suction region 13'.

[0024] The sheet contact mechanism S includes a control means 21 that controls the suction operation from the first to fourth suction regions 13a, 13b, 13c, and 13d. That is, the control means 21 controls the operation of the suction pump 17. The control means 21 may control the suction operation electrically or mechanically. The control means 21 also controls a mechanism, such as a control valve (not shown), for independently performing the suction operation from the first to fourth suction regions 13a, 13b, 13c, and 13d. Therefore, the control means 21 can make the timing of the suction operation from the first to fourth suction regions 13a, 13b, 13c, and 13d different.

[0025] Preferably, if the control means 21 sets the suction timing to suction in the order of the first suction region 13a, which is close to the front end holding portion 11, then the second suction region 13b, the third suction region 13c, and the fourth suction region 13d, then the lifting, wrinkling, and flapping of the sheet 4 can be suppressed more effectively.

[0026] The timing of the operation of the central holding portion 13 and the rear holding portion 12 after the sheet 4 is grasped by the front holding portion 11 of the suction cylinder 10 can be set as appropriate, but it is preferable to hold the sheet 4 with the front holding portion 11, suppress the flapping of the rear end of the sheet 4 with the rear holding portion 12, tension the sheet 4, and then make the sheet 4 adhere tightly to the suction cylinder 10 with the central holding portion 13, as this can further suppress lifting, wrinkling, and flapping of the sheet 4.

[0027] Furthermore, it is most preferable to hold the front end of the sheet 4 with the front end holding portion 11, then hold the rear end of the sheet 4 with the rear end holding portion 12, and then, as described above, adsorb the sheet 4 sequentially from the first suction region 13a of the central holding portion 13, which is close to the front end holding portion 11, toward the suction region close to the rear end holding portion 12, in the central holding portion 13, because this suppresses lifting, wrinkling, and flapping of the sheet 4.

[0028] The sheet adhesion mechanism according to this embodiment provides a sheet adhesion mechanism S that prevents lifting, wrinkling, and flapping of the sheet 4 compared to conventional designs.

[0029] The operation of the rear end holding portion 12 in holding the rear end of the sheet 4 will be described in detail below. Figure 4(a) shows a part of the suction cylinder 10 of the rear end holding portion 12, and Figure 4(b) shows a part of the suction cylinder 10 in which the rear end holding portion 12 tensions the left side 4a of the sheet 4 in a first direction S1 and the right side 4b of the sheet 4 in a second direction S2. In this example, the description will be based on an example in which the suction cylinder 10 is equipped with a rear end holding portion 12 consisting of six rear end suction portions 12aa, 12ab, 12ac, 12aa', 12ab', and 12ac'.

[0030] The rear suction holes 12b of the rear suction sections 12aa, 12ab, and 12ac shown in Figure 4(a) are the parts that suck the left side 4a of the sheet 4, with the dotted line X-X' indicating the center position of the width W of the suction cylinder 10 shown as the boundary. When 0 degrees is defined as the line connecting the center of each movable part 12c in a direction perpendicular to the axial direction S3 of the suction cylinder 10, the rear suction holes 12b of the rear suction sections 12aa', 12ab', and 12ac' that suck the right side 4b of the sheet 4 are positioned at a position rotated by a second angle θ2 when 0 degrees is defined as the line connecting the center of each movable part 12c in a direction perpendicular to the axial direction S3 of the suction cylinder 10. The rear end of the sheet 4 is initially held with the rear suction holes 12b arranged as described above. The first angle θ1 can be set appropriately within the range of 0 to -90 degrees, and the second angle θ2 can be set appropriately within the range of 0 to 90 degrees. In one example of this embodiment, we will describe an example where the first angle θ1 is -10 degrees and the second angle is 10 degrees.

[0031] Subsequently, as shown in Figure 4(b), the rear suction holes 12b of the rear suction sections 12aa, 12ab, and 12ac, which suck the left side 4a of the sheet 4, are rotated by their respective movable parts 12c in a counterclockwise direction from 0 to -90 degrees while sucking the sheet 4, thereby tensing the left side 4a of the sheet 4 in the first direction S1. Similarly, the rear suction holes 12b of the rear suction sections 12aa', 12ab', and 12ac', which suck the right side 4b of the sheet 4, are rotated by their respective movable parts 12c in a clockwise direction from 0 to 90 degrees while sucking the sheet 4, thereby tensing the right side 4b of the sheet 4 in the second direction S2.

[0032] In one example of this embodiment, the rear end suction holes 12b of the rear end suction sections 12aa, 12ab, and 12ac are rotated counterclockwise from the position where the rear end of the sheet 4 is initially held, from the center of the width W of the suction cylinder 10 toward the end of the suction cylinder 10, the rear end suction hole 12b of the rear end suction section 12aa is rotated by -10 degrees, the rear end suction hole 12b of the rear end suction section 12ab is rotated by -30 degrees, and the rear end suction hole 12b of the rear end suction section 12ac is rotated by -60 degrees. Furthermore, the rear end suction holes 12b of the rear end suction sections 12aa', 12ab', and 12ac', respectively, rotate clockwise from the initial position where they hold the rear end of the sheet 4, with the rear end suction hole 12b of the rear end suction section 12aa' rotating 10 degrees, the rear end suction hole 12b of the rear end suction section 12ab' rotating 30 degrees, and the rear end suction hole 12b of the rear end suction section 12ac' rotating 60 degrees. When the sheet 4 separates from the suction section 10, the rear end suction holes 12b return to the initial configuration shown in Figure 4(a). In this way, the rear end suction holes 12b move while suctioning, which tensions both ends of the sheet 4. By tensioning both ends of the sheet 4, wrinkles and rippling can be prevented when the sheet 4 is attached to the suction section 10. The rotation angle of the rear end suction holes 12b can be set as appropriate. Preferably, the rotation angle of the rear end suction hole 12d should increase as you move from the dotted line X-X' toward both ends of the suction cylinder 10.

[0033] Furthermore, the number and position of the rear end suction sections 12a can be adjusted according to the size of the sheet 4 being transported.

[0034] (Second embodiment) In this embodiment, a configuration in which the suction area of ​​the central holding portion 13 of the suction cylinder 10 differs from that of the first embodiment will be described. Figures 5(a) and 5(b) are surface configuration diagrams of suction cylinders 10A and 10B, respectively, in which the central holding portion 13 differs from that of the central holding portion 13 of the first embodiment. Note that the configuration other than the central holding portion 13 is the same as that of the suction cylinder 10 described in the first embodiment, so a detailed explanation will be omitted.

[0035] The central holding portion 13 of the suction cylinder 10A shown in Figure 5(a) has six suction regions 13e, 13f, 13g, 13h, 13i, and 13j, and each of these suction regions 13e, 13f, 13g, 13h, 13i, and 13j is located along the axial direction S3 of the suction cylinder 10A. The central holding portion 13 only needs to have at least two suction regions 13', and each of the suction regions 13e, 13f, 13g, 13h, 13i, and 13j may have a different area. In this embodiment, six suction regions 13e, 13f, 13g, 13h, 13i, and 13j are shown, but there may be seven or more. The suction cylinder 10A also has suction units 14 inside that correspond to the suction regions 13e, 13f, 13g, 13h, 13i, and 13j.

[0036] In the suction cylinder 10A shown in Figure 5(a), the control means 21 can also make the suction operation timing different for each of the suction regions 13e, 13f, 13g, 13h, 13i, and 13j.

[0037] As an example of the suction operation timing of the suction cylinder 10A shown in Figure 5(a), the control means 21 holds the front end of the sheet 4 with the front end holding part 11 and the rear end of the sheet 4 with the rear end holding part 12. Then, for example, it performs a suction operation from the suction regions 13g and 13h located in the center of the suction cylinder 10A, followed by suction operations from the suction regions 13f and 13i adjacent to the suction regions 13g and 13h, and finally suction operations from the suction regions 13e and 13j. With this suction operation, air is adsorbed from the center of the sheet 4 toward the outside of the sheet 4, so the sheet 4 can be tightly attached to the suction cylinder 10A without the sheet 4 floating, wrinkling, or flapping.

[0038] In the suction cylinder 10B shown in Figure 5(b), the central holding part 13 has 24 suction regions 13k1 to 13k24, with six arranged in the direction of the rotation axis of the suction cylinder 10A and four in the direction of rotation of the suction cylinder 10A. In the configuration shown in Figure 5(b), the central holding part 13 only needs to have at least four suction regions 13', with two in the direction of the rotation axis of the suction cylinder 10A and two in the direction of rotation of the suction cylinder 10A, and each suction region 13' may have a different area. In this embodiment, 24 suction regions 13k1 to 13k24 are shown, but there may be 25 or more. The suction cylinder 10B also has a suction unit 14 inside the suction cylinder 10B that corresponds to each of the suction regions 13'.

[0039] In the suction cylinder 10B shown in Figure 5(b), the control means 21 can also make the suction operation timing from each of the suction regions 13k1 to 13k24 different.

[0040] The control means 21 holds the front end of the sheet 4 with the front end holding part 11 and the rear end of the sheet 4 with the rear end holding part 12. Then, for example, it performs a suction operation from the suction regions 13k9, 13k10, 13k15, and 13k16 located in the central part of the central holding part 13, and then performs a suction operation from the suction region 13' located in the peripheral part of the central holding part 13. With this suction timing, air is drawn from the center of the sheet 4 toward the outside of the sheet 4, so the sheet 4 can be tightly attached to the suction cylinder 10B without the sheet 4 lifting, wrinkling, flapping, or floating.

[0041] According to this embodiment of the sheet adhesion mechanism S, similar to the first embodiment, it is possible to provide a sheet adhesion mechanism S that prevents lifting, wrinkling, and flapping of the sheet 4 compared to the conventional method.

[0042] (Third embodiment) In this embodiment, a sheet adhesion mechanism S that allows for more precise control of the suction timing and suction force by the control means 21 is described, compared to the sheet adhesion mechanism S according to the first and second embodiments. Figures 6(a) and 6(b) are side views of the sheet adhesion mechanism (S), and Figures 6(a) and 6(b) show different sheet adhesion mechanisms (S). In Figures 6(a) and 6(b), only the side views corresponding to Figure 2 are shown, and the explanation of other configurations is omitted, but the control means 21 described in this embodiment can also be applied to the sheet adhesion mechanism S described in the second embodiment.

[0043] The sheet contact mechanism S shown in Figure 6(a) comprises a suction unit 14 consisting of an airbox 15 and a suction tube 16 corresponding to suction regions 13a, 13b, 13c, and 13d, and suction pumps 17a, 17b, 17c, and 17d corresponding to each suction unit 14. The control means 21 controls the operation of each of the suction pumps 17a, 17b, 17c, and 17d. In other words, the control means 21 controls the suction timing and suction force of each of the suction pumps 17a, 17b, 17c, and 17d.

[0044] The seat sealing mechanism S shown in Figure 6(b) is equipped with adjustment valves 18a, 18b, 18c, and 18d on the suction pipe 16 of each suction unit 14. The control means 21 controls each of the adjustment valves 18a, 18b, 18c, and 18d. That is, the control means 21 controls the opening and closing timing and valve opening degree of each of the adjustment valves 18a, 18b, 18c, and 18d.

[0045] The sheet adhesion mechanism S shown in Figures 6(a) and 6(b) further includes a measuring unit 22 for measuring the lifting of the sheet 4 from the suction cylinder 10. The measuring unit 22 is implemented, for example, by a line sensor or an area sensor. Alternatively, the measuring unit 22 may be implemented by the inspection imaging device 5 shown in Figure 1. The measuring unit 22 can measure the suction state of the sheet 4 online and transmit the suction status of the sheet 4 and the suction cylinder 10 to the control means 21. The sheet adhesion mechanism S in Figure 6(a) controls the suction timing and suction force of the suction pumps 17a, 17b, 17c, and 17d. The sheet adhesion mechanism S in Figure 6(b) can control the opening and closing timing and valve opening of the adjustment valves 18a, 18b, 18c, and 18d.

[0046] According to the sheet adhesion mechanism S of this embodiment, since suction can be controlled according to the suction state of the sheet 4, it is possible to further prevent lifting, wrinkling, and flapping of the sheet 4 compared to the sheet adhesion mechanism S described in the first and second embodiments. [Explanation of Symbols]

[0047] 1 Paper feed section 2. Inspection Department 3. Paper output section 4 sheets 5. Imaging device for inspection 5a Lighting section 6. Paper feed cylinder 7. Paper output side feed cylinder 8 Paper feed plate 10, 10A, 10B Suction cylinder (inspection cylinder) 11 Front end holding part 12 Rear end holding part 12a Rear end suction part 12b Rear end suction hole 12c Moving part 12d Fixed part 13 Central holding part 13´ suction area 13a Suction area (1st suction area) 13b Suction area (second suction area) 13c, 13d, 13e, 13f, 13g, 13h, 13i, 13j suction area 13k1~13k24 Suction area 13A Suction hole 14, 14a, 14b, 14c, 14d Suction Unit 15 Airbox 16, 16a, 16b, 16c, 16d suction tube 17, 17a, 17b, 17c, 17d Suction pump 18a, 18b, 18c, 18d Adjustment valves 21 Control means 22 Measuring part S Sheet Contact Mechanism K Sheet Inspection Device W Axial width of the suction cylinder

Claims

1. A sheet adhesion mechanism having a front end holding portion for holding the front end of the sheet, a rear end holding portion for holding the rear end of the sheet, and a central holding portion for holding the sheet surface of the sheet, on a cylindrical suction cylinder in a printing press, The sheet adhesion mechanism is characterized in that the central holding portion has at least a first suction region and a second suction region, and is equipped with control means for controlling the suction operation of each suction region, wherein the timing of the suction operation performed by the control means for suction from each suction region is different.

2. The sheet adhesion mechanism according to claim 1, characterized in that the control means controls the suction operation to be performed sequentially from the first suction region toward the suction region adjacent to the rear end holding portion, after the front end of the sheet is held by the front end holding portion and the rear end of the sheet is held by the rear end holding portion.

3. The rear end holding portion is comprised of a plurality of rear end suction portions arranged along the axial direction of the suction cylinder, each consisting of a movable portion having at least a rear end suction hole and a fixing portion that fixes the movable portion at a predetermined position on the surface of the suction cylinder. The sheet contact mechanism according to claim 1 or 2, characterized in that, after the sheet is held by the rear end holding portion, the movable portion moves in a direction that tensions the sheet.

4. The sheet adhesion mechanism according to claim 3, characterized in that, in the central holding portion, the first suction region and the second suction region are formed sequentially from a position adjacent to the front end holding portion, and the control means controls the second suction operation timing to be performed after the first suction operation timing.

5. The sheet adhesion mechanism according to claim 1, further comprising a measuring unit for measuring the floating of the sheet from the suction cylinder, wherein the control means controls the suction force according to the floating state measured by the measuring unit.

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