Image formation device

Abstract

To prevent stacking during drum standing by making a clamp plate and a master not contact with each other.SOLUTION: An image formation device includes: a rotatable drum 4 around which a master 21 is wound; a clamp plate 31 that is openably and closeably provided so as to fix or release a tip end of the master 21; a separation fan 71 that blows air to between the clamp plate 31 and the drum 4; and a control unit 9 that rotates the drum 4 so as to be in a printing position of the master 21 immediately after the printing end or after a predetermined time elapses from printing of the master 21 on the drum 4, and controls the clamp plate 31 to be in a state of opening by a predetermined aperture in such a degree that the tip end of the master 21 is not detached.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] The stencil printing device has a drum on which an ink container containing ink is removably mounted, a made master is attached to the drum, and an image is printed on the printing paper by pressing the printing paper against the drum on which the master is attached.

[0003] When a master is loaded into a stencil printing machine, the leading edge of the master is clamped with a clamp plate on the drum. However, if the drum is left for a long period of time (approximately one month or more) after printing, ink oil can seep into the clamp plate through the surface of the master, causing the master to stick to the clamp plate, resulting in failure of the master discharge preparation operation.

[0004] Patent Document 1 describes a technology in which, when the elapsed time from when the stencil paper was last wound around the first drum is equal to or greater than a predetermined elapsed time threshold, the stencil paper clamp section is rotated to a second rotation angle that is greater than the first rotation angle under normal circumstances (paragraph

[0052] , etc.).

[0005] Patent Document 2 describes a technique in which a releasing operation is performed multiple times to release the stencil sheet fixed to the drum by a clamp portion from the fixed state (paragraph

[0050] , etc.). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2012-240239 A [Patent Document 2] JP 2019-064041 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the techniques described in Patent Documents 1 and 2 have the problem that the master cannot be separated from the clamp plate when the adhesion strength is high, which requires the user to manually peel off the master from the clamp plate and discard it, which is time-consuming and makes the user's hands dirty.

[0008] SUMMARY OF THE PRESENT DISCLOSURE ... The present invention has been made in consideration of the above problems, and has an object to provide an image forming apparatus in which the clamp plate and the master are kept out of contact with each other while the drum is left unused, thereby preventing sticking. [Means for solving the problem]

[0009] In order to achieve the above object, the image forming apparatus according to the present invention is characterized in that: a rotatable drum on which the master is wound; a clamp plate that can be opened and closed to fix or release the tip of the master; a blower that blows air between the clamp plate and the drum; a control unit which rotates the drum to the mounting position of the master immediately after printing is completed or after a predetermined time has elapsed since the master is mounted on the drum, and controls the clamp plates to be open by a predetermined angle so that the leading edge of the master does not slip out; The reason is that it is equipped with the following features. Effect of the Invention

[0010] According to the features of the image forming apparatus of the present invention, the clamp plate and the stencil can be kept out of contact with each other while the drum is left standing, thereby preventing sticking of the stencil. Also, by blowing air between the clamp plate and the drum with an air blowing device before reclamping the stencil with the clamp plate, it is possible to prevent the stencil from shifting out of position. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a stencil printing apparatus 1 according to a first embodiment of the present invention. [Diagram 2]FIG. 2 is an explanatory diagram illustrating an air current generated by a separation fan provided in the stencil printing machine 1 according to the first embodiment of the present invention. [Diagram 3] 1A and 1B are explanatory diagrams illustrating the opening and closing operation of a clamp plate provided in a stencil printing apparatus 1 according to a first embodiment of the present invention, in which (a) shows the clamp plate in a closed state, and (b) shows the clamp plate in an open state. [Figure 4] 1A and 1B are diagrams illustrating the operation of the stencil printing machine 1 according to the first embodiment of the present invention immediately after printing is completed or after a predetermined time has elapsed since the master is attached to the drum. (a) shows a state during standby for printing, (b) shows a master discharge preparation operation, (c) shows a printing preparation operation, and (d) shows a state in which printing preparation is completed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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.

[0013] 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.

[0014] FIG. 1 is a schematic diagram of a stencil printing apparatus (image forming apparatus) according to a first embodiment of the present invention.

[0015] As shown in Figure 1, the stencil printing apparatus 1 according to the first embodiment of the present invention mainly includes a plate making unit 2, an image reading unit 3, a drum 4, an ink container 5, a paper feeding unit 6, a paper discharge unit 7, a plate discharge unit 8, and a control unit 9.

[0016] The image reading section 3 is provided on the upper part of the stencil printing machine 1, and optically reads image data from an original placed on a contact glass (not shown) using an image sensor, and converts it into an electrical signal.

[0017] The plate making section 2 pulls out a rolled long master 21, makes a plate on the master 21 using image data included in a print job received from the outside as a plate making image using a thermal head 22, and cuts the master 21 using a master cutter 23.

[0018] The drum 4 is rotated in the direction of arrow A in Fig. 1 by the driving force of a main motor (not shown). Ink is supplied to the stencil 21 attached to the drum 4, and a printing paper 61 is pressed against the inked stencil 21 by a press roll 32 or the like, so that an image corresponding to the image data is printed on the printing paper 61.

[0019] A clamp plate 31 is provided on the outer periphery of the drum 4. The clamp plate 31 clamps the leading end of the master 21 on which the image data has been made into a plate by the plate making section 2, and attaches the master to the drum 4.

[0020] This stencil printing device 1 is provided with a reference position detection sensor (not shown) for detecting the reference position of the drum 4 and positioning the drum 4 at a master clamp position, etc., and a rotary encoder (not shown) for detecting the rotation of the main motor, and the rotational position of the drum 4 can be detected by detecting the output pulse of the rotary encoder based on the detection result of the reference position detection sensor.

[0021] The ink container 5 contains ink to be supplied to the drum 4, and is configured to be detachable from the drum 4. The attached ink container 5 is provided inside the drum 4.

[0022] The paper feed section 6 includes a paper feed table 62 on which printing papers 61 are stacked, primary paper feed rolls 63, 64 that transport only the topmost printing paper 61 from the paper feed table 62, a pair of secondary paper feed rolls 65, 66 that transport the printing paper 61 transported by the primary paper feed rolls 63, 64 between the drum 4 and the press roll 32 in synchronization with the rotation of the drum 4, and a paper feed sensor 67 that detects whether the printing paper 61 has been transported between the pair of secondary paper feed rolls 65, 66.

[0023] The paper discharge section 7 has a separation fan 71 that separates the printed paper 61 that has been printed from the drum 4, a suction unit 72 that has a suction means and a conveying belt that sucks in the printed paper 61 separated from the drum 4 by the separation fan 71, and a paper discharge tray 73 on which the printed paper 61 discharged by the conveying belt of the suction unit 72 is placed.

[0024] As shown in Fig. 2, the separation fan 71 blows air toward the drum 4. The air blown toward the drum 4 is separated into an air current F1 that is sent upward along the drum 4 and an air current F2 that is sent downward along the drum 4. When the drum 4 is in the mounting position for the master 21 shown in Fig. 2, the air current F1 reaches between the clamp plate 31 and the drum 4.

[0025] The master discharge section 8 has a master discharge unit 81 which removes the master 21 from the drum 4 after the master discharge unit 81 has been released from the outer peripheral surface of the drum 4, and a master discharge box 82 which stores the master 21 removed by the master discharge unit 81. The master 21 conveyed into the master discharge box 82 by the master discharge unit 81 is pushed to the back of the master discharge box 82 by a compression mechanism 83.

[0026] The control unit 9 controls various functions in the stencil printing machine 1. The detailed configuration of the control unit 9 will be described later. The control unit 9 also controls the drum 4 to rotate so as to be at the attachment position of the stencil 21 immediately after printing is completed or after a predetermined time has elapsed since the attachment of the stencil 21 to the drum 4, and controls the clamp plate 31 to be opened to a predetermined degree so as to prevent the leading end of the stencil 21 from slipping out.

[0027] Here, the opening and closing operation of the clamp plate 31 will be described.

[0028] FIG. 3 is an explanatory diagram illustrating the opening and closing operation of the clamp plate 31, where (a) is a diagram showing the clamp plate 31 in a closed state, and (b) is a diagram showing the clamp plate 31 in an open state.

[0029] As shown in FIG. 3( a ), when the clamp plate 31 is in a closed state, the clamp plate 31 clamps the leading end of the master 21 .

[0030] As shown in FIG. 3(b), a flip-up plate 34 for flipping up the paper 61 is provided near the clamp plate 31.

[0031] The clamp plate 31 and the flip-up plate 34 are opened and closed by raising and lowering a clamp cam 331 of the cam portion 33. Specifically, when a cam shaft 332 of the cam portion 33 rotates in the direction of the arrow, the clamp cam 331 descends in the direction of the arrow.

[0032] Then, with the clamp cam 331 in the lowered state, as shown in FIG. 3(b), the drum 4 rotates to the mounting position of the master 21, whereby the clamp cam 331 abuts against the cam follower 333 and the clamp plate 31 opens, and then the clamp cam 331 abuts against the cam follower 334 and the flip-up plate 34 opens.

[0033] Fig. 4 is a diagram for explaining the operation of the stencil printing machine 1 according to the first embodiment of the present invention immediately after the completion of printing or after a predetermined time has elapsed since the master 21 was attached to the drum 4. Fig. 4(a) shows a state during standby for printing, (b) shows a master discharge preparation operation, (c) shows a printing preparation operation, and (d) shows a state in which printing preparation is completed.

[0034] Hereinafter, a case where the master 21 is replaced and a case where the master 21 is not replaced (non-replacement) will be described separately with reference to FIG.

[0035] (When replacing Master 21) When replacing the master 21, the control unit 9 rotates the drum 4 to the master removal / mounting position (home position) of the master 21 as shown in Figure 3 immediately after printing is completed or after a predetermined time has elapsed since the master 21 was mounted on the drum 4.

[0036] Then, the control unit 9 puts the clamp plate 31 into the fully open state.

[0037] Next, as shown in FIG. 4(b), the control unit 9 fully opens the flip-up plate 34 to peel off the leading edge of the stencil 21 from the drum 4, then rotates the drum 4 to deliver the leading edge of the stencil 21 to the master discharge unit 81. While continuing to rotate the drum 4, the control unit 9 drives the drive unit of the master discharge unit 81 to store the stencil 21 in a master discharge box 82 and compress it with the compression mechanism 83, thereby completing the master discharge process.

[0038] After the master is removed, the control unit 9 rotates the drum to move it to the mounting position, and with the clamp plate 31 fully open, guides the leading edge of the master 21 under the clamp plate 31. At this time, the flip-up plate 34 is in a fully closed state. Next, the clamp plate 31 is fully closed, and the leading edge of the master 21 is clamped to the drum. Then, while rotating the drum 4, the master 21 is wrapped around the outer periphery of the drum 4 and mounted, completing the printing preparation state (the state shown in FIG. 4(d)).

[0039] (If Master 21 is not replaced) If the master 21 is not to be replaced, the control unit 9 similarly rotates the drum 4 to the master removal / mounting position (home position) of the master 21 as shown in FIG. 3 immediately after printing is completed or after a predetermined time has elapsed since the master 21 was mounted on the drum 4.

[0040] Then, as shown in FIG. 4(a), the control unit 9 controls the clamp plate 31 to be opened to a predetermined degree (here, only halfway) so that the leading end of the master 21 does not slip out.

[0041] As a result, as shown in FIG. 4( c ), an airflow F1 along the drum 4, which is generated by the airflow from the separation fan 71, reaches between the clamp plate 31 and the drum 4.

[0042] When printing is to be performed, the control unit 9 causes the clamp plate 31 to be fully closed, thereby causing the master 21 to be attached to the drum 4, as shown in FIG. 4(d).

[0043] The control unit 9 rotates the drum 4 to the master unloading / mounting position (home position) of the master 21 immediately after printing is completed, and controls the clamp plate 31 to be open by a predetermined angle so that the leading edge of the master 21 does not fall out, which is effective even when the power is turned off while the stencil printing machine 1 is left unused. Furthermore, the control unit 9 rotates the drum 4 to the master unloading / mounting position (home position) of the master 21 a predetermined time after the master 21 is loaded onto the drum 4, and controls the clamp plate 31 to be open by a predetermined angle so that the leading edge of the master 21 does not fall out, thereby reducing time loss at the start of each printing.

[0044] 2, the separation fan 71 of the stencil printing machine 1 according to the first embodiment of the present invention is configured to blow air toward the drum 4, and the air blown toward the drum 4 is separated into an air current F1 blown upward along the drum 4 and an air current F2 blown downward along the drum 4, but this is not limiting. For example, the direction of air blown by the separation fan 71 may be variable, and when the paper 61 is separated from the drum 4, the air blowing direction may be downward so that the air current F2 is formed, and when air is blown between the clamp plate 31 and the drum 4, the air blowing direction may be upward so that the air current F1 is formed.

[0045] (Additional Note) This application discloses the following inventions.

[0046] (Appendix 1) a rotatable drum on which the master is wound; a clamp plate that can be opened and closed to fix or release the tip of the master; a blower that blows air between the clamp plate and the drum; a control unit which rotates the drum to the mounting position of the master immediately after printing is completed or after a predetermined time has elapsed since the master is mounted on the drum, and controls the clamp plates to be open by a predetermined angle so that the leading edge of the master does not slip out; An image forming apparatus comprising:

[0047] This prevents the clamp plate and the stencil from coming into contact with each other while the drum is left in place, preventing them from sticking to each other. By blowing air between the clamp plate and the drum with an air blowing means before reclamping the stencil with the clamp plate, it is possible to prevent the stencil from shifting out of position. [Explanation of symbols]

[0048] 1 Stencil printing device 2 Plate making department 3 Image reading section 4 Drums 5 Ink container 6 Paper feed section 7 Paper output section 8 Discharge section 9. Control Unit 21 Master 31 Clamp plate 33 Cam section 34 Flip-up board 61 Paper 71 Separate Fan 331 Clamp Cam 332 Camshaft

Claims

[Claim 1] a rotatable drum on which the master is wound; a clamp plate that can be opened and closed to fix or release the tip of the master; a blower that blows air between the clamp plate and the drum; a control unit which rotates the drum to the mounting position of the master immediately after printing is completed or after a predetermined time has elapsed since the master is mounted on the drum, and controls the clamp plates to be open by a predetermined angle so that the leading edge of the master does not slip out; An image forming apparatus comprising:

Images