Image formation device

Abstract

To prevent a sheet in a floating state from being conveyed without lowering productivity even if the sheet floats.SOLUTION: An image formation device comprises: a suction conveyance part 3 which is provided below a printing part 4 and conveys a printing medium; a sheet flotation first sensor 42 which is provided upstream from the printing part 4 and detects the conveyed printing medium deforming; a discharge part 41 which retracts the printing medium PA; a changeover part 44 which is provided nearby a conveyance path where the printing medium is conveyed between the suction conveyance part 3 and sheet flotation first sensor 42, and makes a changeover to convey the printing medium to a path of the suction conveyance part 3 or discharge part 41; and a control part 7 which lets a first flipper move so that the printing medium is guided to the discharge part 41, or the printing medium being conveyed is caught by an end of the first flipper or a second flipper to correct its deformation at the timing when the sheet flotation first sensor 42 detects the printing medium deforming.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus that conveys and prints on a print medium. [Background technology]

[0002] A line-type inkjet recording apparatus performs printing by ejecting ink from an inkjet head onto paper that is transported under suction, based on image data.

[0003] In this case, if the paper being suction-transported becomes deformed due to bent edges or curling, continuing to transport the paper may cause the deformed paper to collide with the bottom of the inkjet head. As a result, the paper may not be able to continue being transported and may remain inside the device. In such cases, the user must remove the paper, which creates the problem of downtime.

[0004] Patent document 1 discloses an inkjet recording device that, when paper floating is detected by a paper floating detection means, stops the conveying operation of the conveying means and peels the adsorbed paper off the conveying belt, thereby stopping the conveying operation while keeping the paper held by the conveying means. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-13676 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the inkjet recording device described in Patent Document 1, when the paper floats by a large amount, the head gap needs to be increased and the head needs to be operated precisely, which requires a long time for movement and can reduce productivity.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an image forming device that prevents paper in which floating has occurred from being transported without reducing productivity, even if the paper floats. [Means for solving the problem]

[0008] In order to achieve the above object, the image forming apparatus according to the present invention is characterized in that: An image forming unit; a conveying unit that is disposed below the image forming unit and conveys a print medium; a detection unit provided upstream of the image forming unit and configured to detect deformation of the transported print medium; a discharge section that evacuates the print medium below the transport means; a switch unit that is provided near a transport path along which the print medium is transported between the transport means and the detection unit, and that switches so as to transport the print medium to either the transport means or the discharge unit; A control unit that operates the switching unit, the switching unit includes a first flipper provided below the transport path and a second flipper provided downstream of the first flipper and above the transport path; The control unit is Depending on the timing when the detection unit detects deformation of the printing medium, the first flipper is operated to guide the printing medium to the discharge unit, or the first flipper is operated to hook the end of the first flipper or the second flipper to correct deformation of the printing medium being transported. Effect of the Invention

[0009] According to the features of the image forming device of the present invention, it is possible to prevent deformed printing media from coming into contact with the inkjet head, so that even if paper floating occurs, it is possible to prevent a decrease in productivity by correcting the paper floating. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of an inkjet printing apparatus according to an embodiment of the present invention. [Diagram 2] 1A and 1B are explanatory diagrams illustrating the operation of an inkjet printing device according to an embodiment of the present invention, in which (a) and (b) show the operation when the leading edge of the transported print medium is warped up so as to float, (c) and (d) show the operation when the trailing edge of the transported print medium is warped up so as to float, and (e) and (f) show the operation when the deformation of the transported print medium PA cannot be corrected and the floating of the print medium is detected by the second paper floating sensor. [Diagram 3] (a) shows the state of the first and second flippers during normal transport, (b) shows the state of the first and second flippers when the leading edge of the print medium is deformed to float, (c) shows the state of the first and second flippers when the trailing edge of the print medium is deformed to bend downward, and (d) shows the state of the first and second flippers when the trailing edge of the print medium is deformed to bend upward. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings. However, it should be noted that the drawings are schematic and may differ from the actual product. In addition, the drawings may include parts with different dimensional relationships and ratios.

[0012] The embodiments described below are merely examples of devices for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not limit the arrangement of each component to that described below. Various modifications can be made to the technical idea of ​​the present invention within the scope of the claims.

[0013] (Configuration of inkjet printing device 1) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an inkjet printing apparatus 1 to which an image forming apparatus according to the present invention is applied will be described in detail below with reference to the accompanying drawings.

[0014] FIG. 1 is a schematic diagram of an inkjet printing apparatus 1 according to an embodiment of the present invention.

[0015] In the following description, the front side of the paper in Fig. 1 where the user is positioned is referred to as the left direction, and the back side of the paper is referred to as the right direction. Furthermore, in Fig. 1, up and down as seen by the user is referred to as the up and down direction. Furthermore, the path indicated by the dashed line in Fig. 1 is the transport path R1 along which paper PA, which is a printing medium, is transported, and the transport direction of paper PA is referred to as the front-to-rear direction. The path indicated by the dashed line in Fig. 1 is the abnormal paper discharge path R2 along which paper PA, which is an abnormal printing medium that has undergone deformation such as floating or curling, is transported. In the following description, upstream means the forward direction, and downstream means the backward direction.

[0016] As shown in FIG. 1, the inkjet printing apparatus 1 includes a paper feed section 2, a suction transport section 3, a printing section 4, a paper discharge section 6, and a control section .

[0017] The paper feed unit 2 feeds paper PA, which is a print medium, and includes a paper feed tray 11, a paper feed roller 12, and a registration roller 13.

[0018] The paper feed tray 11 is stacked with paper PA to be used for printing.

[0019] The paper feed roller 12 picks up the paper PA stacked on the paper feed tray 11 one by one and transports the paper PA toward the registration rollers 13. The paper feed roller 12 is disposed above the paper feed tray 11. The paper feed roller 12 is driven to rotate by a motor (not shown).

[0020] The registration rollers 13 temporarily stop the paper PA conveyed by the paper feed rollers 12, and then convey the paper PA toward the suction conveying section 3. The registration rollers 13 are disposed downstream of the paper feed rollers 12. The registration rollers 13 are rotated by a motor (not shown).

[0021] The suction transport section 3 transports the paper PA transported from the registration rollers 13 toward the printing section 4 and the paper discharge section 6. The suction transport section 3 includes a transport belt 21, a drive roller 22, driven rollers 23-25, a belt drive motor 26, a platen plate 27, and a suction fan 28.

[0022] The conveyor belt 21 is a circular endless belt stretched around a drive roller 22 and driven rollers 23 to 25. The conveyor belt 21 has intake holes, which are through holes for attracting and holding the paper sheet PA, formed at predetermined intervals along the conveying direction of the conveyor belt 21. The conveyor belt 21 attracts and holds the paper sheet PA on the conveyor belt 21 by a negative pressure (adsorption force) generated in the intake holes by driving the suction fan 28.

[0023] 1 by being rotated by the driving roller 22. As a result, the conveyor belt 21 moves endlessly to convey the paper PA to the right.

[0024] The conveyor belt 21 is stretched around the driving roller 22 and the driven rollers 23 to 25. The driving roller 22 is rotated by a belt driving motor 26 to rotate the conveyor belt 21. The driven rollers 23 to 25 are driven by the driving roller 22 via the conveyor belt 21. The driven roller 23 is disposed at substantially the same height as the driving roller 22 and spaced a predetermined distance from the driving roller 22 in the left-right direction. The driven rollers 24 and 25 are disposed below the driving roller 22 and the driven roller 23, spaced a predetermined distance from each other in the left-right direction, and at substantially the same height.

[0025] The belt drive motor 26 drives the drive roller 22 to rotate.

[0026] The platen plate 27 is disposed below the conveyor belt 21 between the drive roller 22 and the driven roller 23, and slidably supports the lower surface of the conveyor belt 21.

[0027] The suction fan 28 is disposed below the platen 27 and generates a downward airflow.

[0028] The printing unit 4 prints on the paper PA transported by the suction transport unit 3. The printing unit 4 is provided above the suction transport unit 3. The printing unit 4 is fixed inside a housing (not shown) of the inkjet printing device 1. The printing unit 4 includes inkjet heads 31 for black (K), cyan (C), magenta (M), and yellow (Y), and a head holder 32.

[0029] The inkjet head 31 has multiple nozzles at the bottom, and prints by ejecting ink from the nozzles onto the paper PA that is transported while being sucked by the suction transport unit 3. The nozzles form a nozzle row that is linearly arranged, as described below.

[0030] The head holder 32 holds the inkjet head 31 above the suction transport unit 3. The head holder 32 is formed in a hollow, substantially rectangular parallelepiped shape.

[0031] A first paper float sensor 42 that detects deformation such as float of the print medium PA transported on the transport path R1 is provided downstream of the registration rollers 13 on the transport path R1 and near the registration rollers 13. In addition, a second paper float sensor 43 that detects deformation such as float of the print medium PA transported on the transport path R1 is provided near the head holder 32 upstream of the printing unit 4.

[0032] Between the first paper floating sensor 42 and the second paper floating sensor 43 on the transport path R1, a discharge section 41 is provided which branches off from the transport path R1 and guides the paper PA to an abnormal paper discharge path R2 below the suction transport section 3.

[0033] A switching unit 44 is provided at the branch point between the transport path R1 and the abnormal paper discharge path R2.

[0034] The switching unit 44 has a first flipper 44a arranged below the transport path R1 and a second flipper 44b arranged downstream of the first flipper 44a and above the transport path R1, and by operating the first flipper 44a and the second flipper 44b, the switching unit 44 switches between the transport path R1 and the abnormal paper discharge path R2 to transport the printing medium PA.

[0035] The paper discharge section 6 discharges the paper PA printed by the printing section 4.

[0036] The control unit 7 controls the entire inkjet printing device 1, and controls the paper feed unit 2, the suction transport unit 3, the printing unit 4, and the paper discharge unit 6. In particular, the control unit 7 operates the first flipper 44a so as to guide the printing medium PA to the discharge unit 41 in response to the timing at which the first paper float sensor 42 detects floating of the printing medium PA. The control unit 7 also operates the printing medium PA to be transported above the first flipper 44a and below the second flipper 44b so that the folded portion of the printing medium PA is caught on the end of the first flipper 44a or the second flipper 44b and corrected.

[0037] (Operation of inkjet printing device 1) Fig. 2 is an explanatory diagram illustrating the operation of the inkjet printing device 1 according to an embodiment of the present invention. Figs. 2(a) and (b) show the operation when the leading edge of the transported print medium PA is deformed so as to float, Figs. 2(c) and (d) show the operation when the trailing edge of the transported print medium PA is deformed so as to float, and Figs. 2(e) and (f) show the operation when the deformation of the transported print medium PA cannot be corrected and the floating of the print medium PA is detected by the second paper floating sensor 43.

[0038] As shown in FIG. 2(a), when the leading edge of the transported print medium PA is deformed to float and has a floating portion PA1, the first paper floating sensor 42 detects the floating of the print medium PA transported along the transport path R1.

[0039] In this case, the control unit 7 operates the first flipper 44a so as to guide the print medium PA to the discharge unit 41, as shown in FIG. 2(b).

[0040] Figure 3(a) shows the state of the first flipper 44a and the second flipper 44b during normal transport, and Figure 3(b) shows the state of the first flipper 44a and the second flipper 44b when the leading edge of the printing medium PA is warped upward so that it is floating.

[0041] 3(a), the first flipper 44a is provided below the transport path R1. The first flipper 44a is provided rotatably about a rotation shaft 44a1. The second flipper 44b is provided above the transport path R1. The second flipper 44b is provided rotatably about a rotation shaft 44b1.

[0042] When the leading edge of the print medium PA being transported is deformed so as to float, the first flipper 44a rotates upward about the rotation axis 44a1, as shown in Fig. 3(b). As a result, the print medium PA being transported comes into contact with the lower surface of the first flipper 44a and is guided to the entrance of the abnormal paper discharge path R2, and is passed through the abnormal paper discharge path R2, i.e., the discharge section 41, from the entrance of the abnormal paper discharge path R2.

[0043] 2(c), when the trailing edge of the transported print medium PA is bent to float at a floating portion PA2, the first paper floating sensor 42 detects the floating of the print medium PA transported along the transport path R1. At this time, the leading edge of the print medium PA has reached below the inkjet head 31 on the transport path R1.

[0044] In this case, as shown in FIG. 2(d), the control unit 7 operates to transport the printing medium PA above the first flipper 44a and below the second flipper 44b so that the floating portion PA2 of the printing medium PA is hooked onto the end of the second flipper 44b and corrected.

[0045] More specifically, as shown in Fig. 3(d), the printing medium PA is transported above the first flipper 44a and below the second flipper 44b. In this state, the first flipper 44a is rotated upward about the rotation shaft 44a1, and the second flipper 44b is rotated downward about the rotation shaft 44b1. As a result, the floating portion PA2 of the printing medium PA is caught by the end portion 44b2 of the second flipper 44b, and the fold is corrected.

[0046] It should be noted that even if the trailing edge of the print medium PA is bent downward, it can be straightened in a similar manner.

[0047] FIG. 3(c) shows the state of the first flipper 44a and the second flipper 44b when the trailing edge of the printing medium PA is bent downward.

[0048] 3(c), the printing medium PA is transported above the first flipper 44a and below the second flipper 44b, and in this state, the first flipper 44a is rotated upward about the rotation shaft 44a1, and the second flipper 44b is rotated downward about the rotation shaft 44b1. As a result, the floating portion PA3 of the printing medium PA is caught by the end portion 44a2 of the first flipper 44a, and the fold is corrected.

[0049] The print medium PA that has been corrected by the switching unit 44 is further transported on the transport path R1, as shown in Fig. 2(e). If the second paper floating sensor 43 detects floating of the rear end of the print medium PA transported on the transport path R1, this means that the correction of the print medium PA by the switching unit 44 has been insufficient.

[0050] If the transport of the printing medium PA continues in this state, there is a possibility that the floating portion of the printing medium PA will come into contact with the lower portion of the inkjet head 31.

[0051] Therefore, the control unit 7 urgently stops the suction transport unit 3. Then, the control unit 7 drives the transport belt 21 of the suction transport unit 3 in the reverse direction, thereby transporting the print medium PA upstream.

[0052] 2(f), the second flipper 44b maintains a state of being rotated downward about the rotation shaft 44b1. As a result, the rear end of the print medium PA transported upstream comes into contact with the underside of the second flipper 44b and is guided to the entrance of the abnormal paper discharge path R2, and is passed through the abnormal paper discharge path R2, i.e., through the discharge section 41.

[0053] (Additional Note) This application discloses the following inventions.

[0054] (Appendix 1) An image forming unit; a conveying unit that is disposed below the image forming unit and conveys a print medium; a detection unit provided upstream of the image forming unit and configured to detect deformation of the transported print medium; a discharge section that evacuates the print medium below the transport means; a switch unit that is provided near a transport path along which the print medium is transported between the transport means and the detection unit, and that switches so as to transport the print medium to either the transport means or the discharge unit; A control unit that operates the switching unit, the switching unit includes a first flipper provided below the transport path and a second flipper provided downstream of the first flipper and above the transport path; The control unit is According to a timing when the detection unit detects the deformation of the print medium, the first flipper is operated so as to guide the print medium to the discharge unit, or the deformation of the print medium being transported is corrected by hooking an end of the first flipper or the second flipper. 1. An image forming apparatus comprising:

[0055] This allows deformation of the printing medium to be detected and the deformed printing medium to be prevented from coming into contact with the inkjet head by either ejecting the deformed printing medium or correcting the deformation, so that even if paper floating occurs, a decrease in productivity can be prevented by correcting the paper floating. [Explanation of symbols]

[0056] 1 Inkjet printing device 2 Paper feed section 3. Suction and transport section 4 Printing Department 6 Paper output section 7 Control section 31 Inkjet head 41 Discharge section 42 First Sensor 43 Second Sensor 44 Switching section 44a 1st Flipper 44a1 Rotating shaft 44a2 end 44b 2nd Flipper 44b1 Rotation axis 44b2 End R1 Transport route R2 Abnormal paper ejection path

Claims

1. An image forming unit; a conveying unit that is disposed below the image forming unit and conveys a print medium; a detection unit provided upstream of the image forming unit and configured to detect deformation of the transported print medium; a discharge section that evacuates the print medium below the transport means; a switch unit that is provided near a transport path along which the print medium is transported between the transport means and the detection unit, and that switches so as to transport the print medium to either the transport means or the discharge unit; A control unit that operates the switching unit, the switching unit includes a first flipper provided below the transport path and a second flipper provided downstream of the first flipper and above the transport path, The control unit is According to a timing when the detection unit detects the deformation of the print medium, the first flipper is operated so as to guide the print medium to the discharge unit, or the deformation of the print medium being transported is corrected by hooking an end of the first flipper or the second flipper.

1. An image forming apparatus comprising:

Images