JP2015052725A - Image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording apparatus which has a simple apparatus configuration and can discharge a printing plate reliably, independently of the type of the printing plate.SOLUTION: A printing plate 3 is delivered from the peripheral surface of a recording drum 10 along a first tangent plane 81 which is the tangent plane of a squeezer roller 18 in the contact line between the squeezer roller 18 and the printing plate 3 held on the recording drum 10. In a discharge part 30, a discharge target position 38 is set on the lower side relative to the first tangent plane 81. The rotational speed of the recording drum 10 is controlled so that the tip of the printing plate 3 delivered from the peripheral surface of the rotating recording drum 10 along the first tangent plane 81 hangs down owing to gravity and reaches the discharge target position 38. Since the discharge target position 38 is set on the lower side relative to the first tangent plane 81 and the printing plate 3 is discharged by utilizing hanging of the tip of the printing plate 3 after exposure owing to gravity, the printing plate can be discharged reliably by the simple configuration, independently of the type of the printing plate.

Description

  The present invention relates to an image recording apparatus for recording an image by winding a sheet-like recording medium such as a printing plate around a recording drum.

  In recent years, in the plate making process, CTP (Computer To Plate) for directly printing image data created by a computer on a printing plate has been widely used. The CTP device, for example, winds a sheet-shaped printing plate around the circumferential surface of a cylindrical recording drum, rotates the recording drum, and scans the recording head that emits laser light along the axial direction of the recording drum. Record the image on the plate.

  Such a so-called outer surface cylindrical recording type CTP apparatus is provided with a mechanism for supplying and discharging the printing plate to and from the recording drum. For example, Patent Document 1 discloses a mechanism that supplies a printing plate to a drum using a supply guide panel and guides one end of the printing plate to a predetermined discharge path by sandwiching one end of the plate with a discharge guide roller. Further, in Patent Document 2, a supply mechanism and a discharge mechanism are provided in different directions as viewed from the peripheral surface of the recording drum, and the position of the squeegee roller that presses the recording drum is switched between when the printing plate is supplied and when it is discharged. Techniques for making them disclosed are disclosed. Further, in Patent Document 3, a discharge mechanism is provided on the upper side of the supply mechanism, and when the holding by the chuck is released, the press plate jumps up from the recording drum by the elastic force of the press plate, and the discharge mechanism uses the press plate. A technique for exhausting is disclosed.

JP 2002-258491 A JP 2011-75793 A JP 2003-72016 A

  However, the techniques disclosed in Patent Documents 1 and 2 require a drive mechanism for moving the discharge guide roller and the squeegee roller, which increases the number of drive parts, increases the cost of the device, and complicates the device configuration. There was a problem of becoming. The technique disclosed in Patent Document 3 is configured to discharge the printing plate using the elastic force of the printing plate, although it is possible to prevent an increase in the number of driving parts and prevent the device configuration from becoming complicated. . The elastic force of the printing plate varies depending on its material and thickness. There are a wide variety of materials and thicknesses of printing plates that are actually used, and some of them have weak elasticity. In the technique disclosed in Patent Document 3, when a printing plate having a weak elastic force is used, the printing plate cannot jump up to the upper discharge mechanism and is discharged to the lower supply mechanism. Arise.

  The present invention has been made in view of the above problems, and an object thereof is to provide an image recording apparatus capable of reliably discharging a printing plate with a simple apparatus configuration regardless of the type of the printing plate.

  In order to solve the above-mentioned problems, the invention of claim 1 is a cylindrical recording in which an image recording apparatus for recording an image on a sheet-like recording medium is rotatably provided and is wound around a cylindrical peripheral surface. A drum, a drum rotating unit that rotates the recording drum about the cylindrical central axis, a rotation control unit that controls the rotation of the recording drum, and a supply of a recording medium to the circumferential surface of the recording drum An image recording unit that records an image on a recording medium held on the peripheral surface of the recording drum, a discharge unit that receives and discharges a recorded recording medium sent from the peripheral surface of the recording drum, A cylindrical squeegee roller provided in parallel with a central axis of the recording drum so as to be in contact with and away from the circumferential surface of the recording drum, and the squeegee roller is held on the recording drum at the discharge portion. The discharge target position is set below the first tangential plane which is the tangential plane of the squeegee roller at both contact lines when contacting the recorded recording medium, and the rotation control unit is configured to rotate the recording drum. Controlling the drum rotating unit so that the leading end of the recording medium that is separated from the peripheral surface of the recording medium by the contact line and is fed along the first tangential plane hangs down due to gravity and reaches the discharge target position. It is characterized by.

  According to a second aspect of the present invention, in the image recording apparatus according to the first aspect of the present invention, a contact position where the recording medium held on the recording drum and the squeegee roller contact each other, and a recording medium held on the recording drum, The squeegee roller further includes a squeegee roller moving mechanism for moving the squeegee roller between the squeegee roller and a separated position, and the contact position of the squeegee roller is located at a specific coordinate position with a central axis of the recording drum as a coordinate origin. It is characterized by that.

  According to a third aspect of the present invention, in the image recording apparatus according to the first or second aspect of the present invention, the leading end of the recording medium fed from the circumferential surface of the recording drum is placed at the discharge target position in the discharge portion. A guide portion for guiding is provided.

  According to a fourth aspect of the present invention, in the image recording apparatus according to the third aspect of the present invention, the guide section includes an upper guide that guides a recording medium heading above the discharge target position to the discharge target position, and the discharge. And a lower guide for guiding a recording medium heading below the target position to the discharge target position.

  According to a fifth aspect of the present invention, in the image recording apparatus according to the fourth aspect of the present invention, the upper guide has a guide surface curved so as to bulge upward.

  According to a sixth aspect of the present invention, in the image recording apparatus according to the fourth aspect of the present invention, the upper guide has a guide surface bent so as to protrude upward.

  The invention according to claim 7 is the image recording apparatus according to any one of claims 3 to 6, wherein the discharge portion includes a pair of cylindrical discharge rollers that are in contact with each other on the circumferential surface, The discharge target position is set to a contact line of the pair of discharge rollers, and the recording medium that has reached the discharge target position is sandwiched and discharged by the pair of discharge rollers.

  According to an eighth aspect of the present invention, in the image recording apparatus according to the seventh aspect of the present invention, the discharge section further includes a roller rotation section that rotates one discharge roller of the pair of discharge rollers. The discharge roller and the roller rotating portion are connected via a one-way clutch that freely rotates the one discharge roller in the direction in which the recording medium is discharged regardless of the operation of the roller rotating portion. And

  According to a ninth aspect of the present invention, in the image recording apparatus according to the eighth aspect of the present invention, the roller rotating portion has a peripheral speed of the pair of discharge rollers that is slower than a speed of the recording medium fed from the recording drum. The one discharge roller is rotated as described above.

  According to a tenth aspect of the present invention, in the image recording apparatus according to any one of the seventh to ninth aspects, the guide portion is a second contact surface that is a common contact plane in a contact line of the pair of discharge rollers. The recording medium is provided so as to be asymptotic to a plane so as to guide the recording medium to the discharge target position.

  According to an eleventh aspect of the present invention, in the image recording apparatus according to any one of the seventh to tenth aspects, the discharge section includes a transport roller for transporting the recording medium discharged by the pair of discharge rollers. Further, the conveyance roller is provided so that a peripheral surface thereof is in contact with the second tangential plane.

  According to a twelfth aspect of the present invention, in the image recording apparatus according to any one of the first to eleventh aspects, the supply line of the recording medium by the supply unit is provided above the first tangential plane. It is characterized by that.

  According to the first to twelfth aspects of the present invention, since the printing plate is discharged by utilizing the fact that the leading edge of the printing plate hangs down due to gravity, it is ensured regardless of the type of the printing plate with a simple apparatus configuration. The printing plate can be discharged.

  Particularly, since the recording medium held on the recording drum and the squeegee roller come into contact with each other at a specific contact position, the squeegee roller moving mechanism can have a simple configuration and a simpler apparatus. It can be configured.

  In particular, according to the third aspect of the present invention, since the guide portion for guiding the leading end of the recording medium fed from the peripheral surface of the recording drum to the discharge target position is provided, the plate is more reliably guided to the discharge target position and discharged. be able to.

  In particular, according to the invention of claim 5, since the upper guide has a guide surface curved so as to swell toward the upper side, the impact of the printing plate hitting the guide surface of the upper guide is mitigated, resulting from the impact. It is possible to prevent damage to the printing plate and occurrence of collision noise.

  In particular, according to the invention of claim 6, since the upper guide has a guide surface bent so as to protrude upward, the impact of the printing plate hitting the guide surface of the upper guide is mitigated, resulting from the impact. It is possible to prevent damage to the printing plate and occurrence of collision noise.

  In particular, according to the ninth aspect of the invention, since one of the discharge rollers is rotated so that the peripheral speed of the pair of discharge rollers is slower than the speed of the recording medium fed from the recording drum, unnecessary stress is applied to the printing plate. Without being acted, the printing plate can be smoothly sandwiched and discharged between the pair of discharge rollers.

  In particular, according to the invention of claim 10, since the recording medium is guided to the discharge target position so as to approach the second tangential plane which is the common tangential plane in the contact line of the pair of discharge rollers, the front end of the printing plate is smoothly It is sandwiched between the pair of discharge rollers, and mechanical damage to the printing plate can be prevented.

  In particular, according to the invention of claim 11, since the conveying roller is provided so that the peripheral surface is in contact with the second tangent plane, the printing plate fed along the second tangential plane from the pair of discharge rollers can be smoothly smoothed. It can be transported by a transport roller.

1 is a diagram illustrating an overall configuration of an image recording apparatus according to the present invention. It is a figure which shows the state which winds a printing plate around the outer peripheral surface of a recording drum. It is a figure which shows the state which is performing the exposure process to a printing plate. It is a figure which shows the state which discharges a printing plate from a recording drum to a discharge part. It is a figure which shows the state from which the front-end | tip vicinity of the printing plate was sent out from the recording drum. It is a figure which shows a mode that the front-end | tip of a printing plate is guide | induced to the discharge target position by a guide part. It is a figure which shows the rotational drive mechanism of a discharge roller. It is a figure which shows the state by which the front-end | tip vicinity of the printing plate was inserted | pinched between a pair of discharge roller. It is a figure which shows the state by which the back end vicinity of the printing plate was sent out from the recording drum. It is a figure which shows the other example of the shape of a guide part. FIG. 10 is a diagram illustrating another example of the positional relationship between the recording drum and the discharge target position. FIG. 10 is a diagram illustrating another example of the positional relationship between the recording drum and the discharge target position.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of an image recording apparatus according to the present invention. In FIG. 1 and the subsequent drawings, the size and number of each part are exaggerated or simplified as necessary for easy understanding.

  The image recording apparatus 1 is a plate making apparatus that records an image by irradiating a printing plate, which is a sheet-like recording medium, with a laser beam. More specifically, image data created by a computer is directly recorded on the printing plate. CTP device. The image recording apparatus 1 includes a recording drum 10, a supply unit 20, a discharge unit 30, and a recording head 50 as main elements. The image recording apparatus 1 includes a control unit 90 that manages the entire apparatus.

  The cylindrical recording drum 10 is provided so as to be rotatable along its central axis 16 in the horizontal direction. The image recording apparatus 1 is provided with a drum rotation motor 15, and the drum rotation motor 15 rotates the recording drum 10 about the center axis 16. The drum rotation motor 15 can rotate the recording drum 10 both clockwise and counterclockwise on the paper surface of FIG. The rotation direction and rotation speed of the recording drum 10 are controlled by the control unit 90.

  The recording drum 10 holds the sheet-like plate 3 wound around its cylindrical peripheral surface. More specifically, a front end clamp 11 and a rear end clamp 12 are attached to the recording drum 10, and both ends of the printing plate 3 are placed between the outer periphery of the recording drum 10 by the front end clamp 11 and the rear end clamp 12. The plate 3 is wound around the outer peripheral surface by sandwiching and fixing. The front end clamp 11 is fixedly installed on the peripheral surface of the recording drum 10, and the rear end clamp 12 is attached to a predetermined position on the peripheral surface of the recording drum 10 by a clamp attaching / detaching mechanism (not shown). The mounting position of the rear end clamp 12 varies depending on the length of the printing plate 3.

  The printing plate 3 is an aluminum alloy thin plate having a photosensitive material applied to its surface. The rigidity of the thin plate-shaped printing plate 3 is mainly defined by the material and the plate thickness. There are a plurality of types of aluminum alloys used for the printing plate 3, and the size and thickness of the printing plate 3 are also various. Accordingly, the rigidity of the plate 3 to be exposed in the image recording apparatus 1 is not uniform. The plate thickness of the plate 3 to be exposed in the image recording apparatus 1 is not particularly limited, but is, for example, 0.15 mm to 0.3 mm.

  The recording head 50 records an image by irradiating the surface of the printing plate 3 held on the peripheral surface of the recording drum 10 with laser light modulated based on predetermined image data. The recording head 50 is slidable in a direction parallel to the central axis 16 of the recording drum 10 by the sub-scanning mechanism 51 (that is, a direction perpendicular to the paper surface of FIG. 1).

  Further, the image recording apparatus 1 is provided with a squeegee roller 18 in the vicinity of the recording drum 10. In the present embodiment, a squeegee roller 18 is provided on the upper left side of the recording drum 10 on the paper surface of FIG. The squeegee roller 18 is a cylindrical roller provided rotatably in parallel with the recording drum 10. The squeegee roller 18 can be brought into contact with and separated from the circumferential surface by a squeegee roller moving mechanism (not shown) between a contact position that contacts the circumferential surface of the recording drum 10 and a spaced position that is separated from the circumferential surface. Note that the contact between the squeegee roller 18 and the recording drum 10 in the present specification includes a case where the squeegee roller 18 contacts the peripheral surface of the recording drum 10 with the printing plate 3 interposed therebetween. The contact position of the squeegee roller is fixed at a specific coordinate position when the central axis 16 is a coordinate origin in a cross section perpendicular to the central axis 16 of the recording drum 10. That is, the squeegee roller 18 contacts the recording drum 10 at a specific contact position.

  When the squeegee roller 18 moves to the contact position, the squeegee roller 18 presses the press plate 3 against the circumferential surface of the recording drum 10 to bring it into close contact therewith. When the squeegee roller 18 is moved to the separated position, the front end clamp 11 and the rear end clamp 12 can pass between the squeegee roller 18 and the peripheral surface of the recording drum 10. Although a mechanism for rotating the squeegee roller 18 alone is not provided, the squeegee roller 18 rotates following the rotation of the recording drum 10 when the squeegee roller 18 is located at the contact position.

  The supply unit 20 includes a tray 21 on which the printing plate 3 is placed and a plurality of supply rollers 22 for feeding the printing plate 3 toward the recording drum 10. The supply unit 20 is provided on the upper right side of the recording drum 10 on the paper surface of FIG. The supply unit 20 supplies the printing plate 3 placed on the tray 21 to the peripheral surface of the recording drum 10 in response to a predetermined operation by the operator.

  The discharge unit 30 includes a guide unit 31, a pair of discharge rollers 36 and 37, and a conveyance belt mechanism 45. In the present embodiment, the discharge unit 30 is provided on the upper right side of the recording drum 10 on the paper surface of FIG. That is, when viewed from the recording drum 10, the supply unit 20 and the discharge unit 30 are provided on the same side, and the discharge unit 30 is provided below the supply unit 20.

  Here, the term “upper side” in the present specification means “relatively upward” and is a concept that includes an upper side obliquely in addition to an upper side in the vertical direction (directly above). Similarly, “lower side” means a relatively lower side, and is a concept that includes a diagonally lower side in addition to a vertically lower side (directly below).

  The discharge unit 30 receives and discharges the recorded (exposed) printing plate 3 sent out from the peripheral surface of the recording drum 10. The discharge unit 30 guides the leading end of the sent printing plate 3 with the guide unit 31, sandwiches the plate 3 with a pair of discharge rollers 36 and 37, and discharges it with the transport belt mechanism 45. The guide unit 31 and the pair of discharge rollers 36 and 37 included in the discharge unit 30 will be described in detail later.

  The control unit 90 controls each operation mechanism provided in the image recording apparatus 1 to advance the image recording process for the printing plate 3. The configuration of the control unit 90 as hardware is the same as that of a general computer. That is, the control unit 90 stores a CPU that performs various arithmetic processes, a ROM that is a read-only memory that stores basic programs, a RAM that is a readable and writable memory that stores various information, control software, data, and the like. It is configured with a magnetic disk. The CPU of the control unit 90 executes a predetermined processing program to control the drum rotation motor 15 and the recording head 50, and the processing in the image recording apparatus 1 proceeds.

  Next, a processing operation in the image recording apparatus 1 having the above configuration will be described. First, the overall operation of recording an image on the printing plate 3 by the image recording apparatus 1 will be outlined, and then the discharging operation of the printing plate 3 after exposure will be described in detail. The plate 3 is placed on the tray 21 of the supply unit 20. Placement of the plate 3 on the tray 21 may be performed manually by an operator (so-called manual feeding), or may be automatically supplied from an autoloader for storing a large number of plate 3. The plate 21 is supplied to the tray 21 one by one.

  After the printing plate 3 is placed on the tray 21, the operator performs a predetermined processing start operation so that the printing plate 3 is supplied from the supply unit 20 to the peripheral surface of the recording drum 10. As shown in FIG. 1, in this embodiment, the tray 21 is provided in an inclined posture in which the supply-side tip is directed to the lower left recording drum 10. Therefore, the plate 3 is sent out toward the peripheral surface of the recording drum 10 by the plurality of supply rollers 22 provided in the tray 21 without providing a special drive mechanism (for example, a motor).

  The printing plate 3 is fed linearly by a plurality of supply rollers 22 of the supply unit 20. Since the tray 21 of the supply unit 20 is provided in an inclined posture, the supply line through which the supply unit 20 sends out the printing plate 3 has a predetermined angle with respect to the horizontal direction. A supply line through which the supply unit 20 feeds the printing plate 3 is provided above a first tangential plane 81 to be described later (see FIG. 2). The supply unit 20 is installed at a position where the supply line passes through both contact lines when the squeegee roller 18 is in contact with the circumferential surface of the recording drum 10.

  When the printing plate 3 is supplied from the supply unit 20, the squeegee roller 18 is moved to a separated position separated from the circumferential surface of the recording drum 10, and the recording drum is positioned so that the front end clamp 11 is positioned in the vicinity of the squeegee roller 18. 10 is rotating and stopping. That is, the recording drum 10 is rotationally driven so that the front end clamp 11 is positioned approximately on the supply line of the printing plate 3. Then, the leading end of the printing plate 3 supplied along the supply line from the supply unit 20 is sandwiched and fixed between the peripheral surface of the recording drum 10 by the front end clamp 11.

  Next, under the control of the control unit 90, the drum rotation motor 15 rotates the recording drum 10 counterclockwise on the paper surface of FIG. 1, and the squeegee roller 18 moves to a contact position where it contacts the peripheral surface of the recording drum 10. The printing plate 3 is pressed and brought into close contact with the peripheral surface of the recording drum 10. As a result, the printing plate 3 is sequentially wound around the circumferential surface of the recording drum 10.

  FIG. 2 is a diagram illustrating a state in which the printing plate 3 is wound around the outer peripheral surface of the recording drum 10. The front end of the printing plate 3 is clamped by the front end clamp 11, and the squeegee roller 18 presses the printing plate 3 against the peripheral surface of the recording drum 10 and rotates the recording drum 10. It is wound around the circumferential surface of the recording drum 10 sequentially toward the end side.

  Eventually, when the rear end of the printing plate 3 is fed from the tray 21 of the supply unit 20 and reaches the vicinity of the peripheral surface of the recording drum 10, the rotation of the recording drum 10 is temporarily stopped and the rear end clamp 12 is moved to the recording drum. 10 is mounted at a predetermined position on the circumferential surface of the recording drum 10, and the rear end is sandwiched between the circumferential surface of the recording drum 10 and fixed. As a result, the entire printing plate 3 is wound around and attached to the circumferential surface of the recording drum 10.

  Subsequently, the squeegee roller 18 moves to a separated position separated from the circumferential surface of the recording drum 10, and the recording drum 10 rotates again about the central axis 16 to move the printing plate 3 to the recording start position. Then, the recording head 50 irradiates the surface of the printing plate 3 with laser light to start image recording.

  FIG. 3 is a diagram showing a state in which the printing plate 3 is subjected to exposure processing. The recording drum 10 around which the printing plate 3 is wound so as to be in close contact with the peripheral surface is rotated by a drum rotation motor 15 about the central axis 16 as a rotation center. As a result, the recording head 50 moves relative to the printing plate 3 in the main scanning direction. The recording head 50 is reciprocated in a direction parallel to the central axis 16 of the recording drum 10 by the sub-scanning mechanism 51. As a result, the recording head 50 moves relative to the printing plate 3 in the sub-scanning direction.

  The recording head 50 irradiates the surface of the printing plate 3 with laser light modulated based on predetermined image data while moving relative to the printing plate 3 in the main scanning direction and the sub-scanning direction. In this way, the surface of the plate 3 is sequentially exposed and image recording proceeds. Note that image data used for image recording, for example, created by a computer outside the apparatus is stored in the storage unit of the control unit 90.

  Next, after the image recording is completed, the drum rotating motor 15 rotates the recording drum 10 clockwise on the paper surface of FIG. 1 under the control of the control unit 90, and the squeegee roller 18 is again moved to the contact position and the printing plate. 3 is discharged from the recording drum 10. The plate 3 sent out from the recording drum 10 is discharged to the discharge unit 30.

  FIG. 4 is a diagram illustrating a state in which the printing plate 3 is discharged from the recording drum 10 to the discharge unit 30. After the exposure by the recording head 50 is completed, the recording drum 10 rotates clockwise on the paper surface while the squeegee roller 18 is separated from the circumferential surface of the recording drum 10, and the rear end clamp 12 passes near the squeegee roller 18. . Subsequently, the squeegee roller 18 moves to the contact position, and the clamping of the printing plate 3 by the rear end clamp 12 is released.

  When the clamping by the rear end clamp 12 is released, the rear end side of the printing plate 3, which is a thin plate of aluminum alloy, jumps up by the elastic force and is separated from the peripheral surface of the recording drum 10. However, since the squeegee roller 18 is in the contact position and presses the printing plate 3 against the peripheral surface of the recording drum 10, the plate 3 is separated from the peripheral surface of the recording drum 10 at a position pressed by the squeegee roller 18. Up to. Then, the recording drum 10 is further rotated clockwise on the paper surface in a state in which the clamping by the rear end clamp 12 is released, whereby the printing plate 3 is sent out from the recording drum 10. The printing plate 3 sent out from the recording drum 10 moves forward while dropping down due to gravity, and is discharged to the discharge unit 30.

  Hereinafter, the discharge of the printing plate 3 to the discharge unit 30 will be described in more detail. Since the traveling direction of the printing plate 3 is reversed between the time when the printing plate 3 is supplied and the time when the printing plate 3 is discharged, in the following description of the discharging operation, the leading edge of the printing plate 3 at the time of supply is used as the trailing edge, and the trailing edge of the printing plate 3 Is described as a tip.

  FIG. 5 is a view showing a state in which the vicinity of the front end of the printing plate 3 is sent out from the recording drum 10. As described above, when the rear end clamp 12 is released, the front end side of the printing plate 3 (the rear end side during supply) jumps up, but the printing plate 3 is separated from the peripheral surface of the recording drum 10. Is the position pressed by the squeegee roller 18. In other words, the plate 3 is sent away from the peripheral surface of the recording drum 10 at the contact line between the squeegee roller 18 and the recording drum 10. At this time, the printing plate 3 is sent out along the first tangential plane 81 passing through both contact lines when the squeegee roller 18 is in contact with the recording drum 10. Strictly speaking, the first tangential plane 81 is a tangential plane of the squeegee roller 18 at a contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10, and is indicated by a one-dot chain line in FIG. The contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10 is a line where the cylindrical peripheral surface of the squeegee roller 18 and the surface of the printing plate 3 are in contact, and the central axis 16 of the recording drum 10. It becomes a line parallel to.

  When the drum rotation motor 15 further rotates the recording drum 10 clockwise on the paper surface, the plate 3 is rotated from the contact line between the squeegee roller 18 and the plate 3 held on the recording drum 10 to the first tangential plane 81 by the rotation. Are sent out sequentially. The speed at which the printing plate 3 is fed is equal to the peripheral speed of the recording drum 10. The peripheral speed is a moving speed of a point on the peripheral surface of the recording drum 10 having a cylindrical shape. The peripheral speed of the recording drum 10 is proportional to the rotational speed of the recording drum 10 by the drum rotation motor 15 and is controlled by the control unit 90. Further, in conjunction with the rotation of the recording drum 10, the squeegee roller 18 also rotates counterclockwise on the paper surface.

  In the present embodiment, a squeegee roller 18 is provided on the upper left side of the recording drum 10 on the paper surface of each drawing. The first tangential plane 81 is perpendicular to a line segment connecting the central axis 16 of the recording drum 10 and the central axis of the squeegee roller 18. Therefore, the first tangent plane 81 is an inclined surface having a predetermined inclination angle with respect to the horizontal plane, and the printing plate 3 fed along the first tangent plane 81 is fed toward the upper right side on the paper surface of each figure. It becomes. When the printing plate 3 is fed obliquely upward from the recording drum 10, gravity acts on the front side of the printing plate 3 with respect to the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10, and the bending is performed. A moment is generated. The tip of the printing plate 3 fed obliquely upward along the first tangent plane 81 from the recording drum 10 hangs downward gradually due to gravity, and the squeegee roller 18 and the printing plate 3 held on the recording drum 10 come into contact with each other. Deflection occurs on the front end side of the printing plate 3 with respect to the line.

  As a result, as shown in FIG. 5, the printing plate 3 fed along the first tangential plane 81 at the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10 is gradually first bent by the deflection. It will bend and move forward away from the tangential plane 81. The degree of deviation from the first tangential plane 81 increases as the distance from the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10 approaches the front end of the printing plate 3. Further, the extent to which the front end of the printing plate 3 deviates from the first tangential plane 81 increases as the amount of the printing plate 3 fed from the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10 increases.

  In the present embodiment, the discharge unit 30 is provided below the first tangential plane 81. Then, the printing plate 3 sent out from the recording drum 10 advances while being bent downward from the first tangential plane 81 and reaches the discharge unit 30 below the first tangential plane 81 (see FIG. 4). ). On the other hand, the supply line through which the printing plate 3 is sent out by the supply unit 20 is provided above the first tangential plane 81.

  The discharge unit 30 includes a guide unit 31, a pair of discharge rollers 36 and 37, and a conveyance belt mechanism 45. The discharge rollers 36 and 37 both have a cylindrical shape and may have the same size. The discharge rollers 36 and 37 are made of, for example, rubber that the plate 3 does not slip. The pair of discharge rollers 36 and 37 are provided in parallel so as to contact each other on the peripheral surface. A contact line between the pair of discharge rollers 36 and 37 is set as a discharge target position 38 in the discharge unit 30. The discharge target position 38 is below the first tangent plane 81. The front end of the printing plate 3 sent out from the peripheral surface of the recording drum 10 along the first tangential plane 81 hangs downward gradually due to gravity, and reaches the discharge target position 38 below the first tangential plane 81. . The plate 3 that has reached the discharge target position 38 is sandwiched between the pair of discharge rollers 36 and 37 and discharged to the transport belt mechanism 45.

  By the way, the trajectory through which the tip of the printing plate 3 sent out from the recording drum 10 passes becomes a curved surface that gradually moves away from the first tangential plane 81 because the printing plate 3 bends due to gravity. The degree of the curvature is defined by the rigidity of the printing plate 3 and the speed at which the printing plate 3 is sent out from the recording drum 10. The higher the rigidity of the printing plate 3 and the higher the speed at which the printing plate 3 is fed out, the smaller the degree of bending of the curved surface and the closer to the first tangential plane 81. The rigidity of the plate 3 is a physical property value that cannot be adjusted by the image recording apparatus 1, but the speed at which the plate 3 is fed from the recording drum 10 can be adjusted by the control unit 90. In other words, the control unit 90 controls the rotational speed of the recording drum 10 to adjust the trajectory through which the front end of the printing plate 3 passes and to reach the discharge target position 38. .

  However, since the discharge target position 38 is a contact line between the pair of discharge rollers 36 and 37, even if the control unit 90 controls the rotation speed of the recording drum 10, the leading end of the printing plate 3 is stably and reliably discharged. It is not easy to reach the position 38. For this reason, the discharge unit 30 is provided with a guide unit 31 for stably and surely leading the leading end of the printing plate 3 fed from the peripheral surface of the recording drum 10 to the discharge target position 38.

  The guide portion 31 is provided closer to the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10 than the pair of discharge rollers 36 and 37. The guide unit 31 includes an upper guide 32 and a lower guide 33. The upper guide 32 guides the leading end of the printing plate 3 that is fed from the recording drum 10 toward the upper side of the discharge target position 38 to the discharge target position 38. On the other hand, the lower guide 33 guides the leading end of the printing plate 3 that is fed from the recording drum 10 toward the lower side of the discharge target position 38 to the discharge target position 38.

  FIG. 6 is a diagram illustrating a state in which the leading end of the printing plate 3 is guided to the discharge target position 38 by the guide unit 31. The upper guide 32 of the guide portion 31 of the present embodiment has a guide surface 32a bent so as to protrude upward at a bending point 32b. The lower guide 33 has a flat guide surface 33a. The guide surfaces 32a and 33a are formed inside the upper guide 32 and the lower guide 33 (the lower surface of the upper guide 32 and the upper surface of the lower guide 33), respectively. The guide surface 32a of the upper guide 32 is an inclined surface directed obliquely downward from the bending point 32b on the tip side (opposite to the discharge target position 38) from the bending point 32b, and is proximal (discharging) from the bending point 32b. On the side close to the target position 38), the surface is generally horizontal. The guide surface 33 a of the lower guide 33 is a flat inclined surface that extends obliquely downward from the discharge target position 38.

  As indicated by an arrow AR61 in FIG. 6, the front end of the printing plate 3 fed from the peripheral surface of the recording drum 10 and directed upward from the discharge target position 38 reaches the guide surface 32a of the upper guide 32, and the guidance thereof. It is guided to the discharge target position 38 along the surface 32a. The front end of the printing plate 3 fed toward the vicinity of the front end of the upper guide 32 proceeds at a relatively large angle with respect to the horizontal plane, but is bent so that the guide surface 32a of the upper guide 32 protrudes upward. Because of this shape, the tip of the plate 3 abuts against the guide surface 32a at a relatively small angle. Therefore, the impact of the printing plate 3 hitting the guide surface 32a of the upper guide 32 is alleviated, and damage to the printing plate 3 and occurrence of collision noise due to the impact can be prevented. Further, the exposed surface of the printing plate 3 does not contact the upper guide 32.

  On the other hand, as indicated by an arrow AR 62 in FIG. 6, the leading edge of the printing plate 3 that is fed out from the circumferential surface of the recording drum 10 and goes below the discharge target position 38 reaches the guide surface 33 a of the lower guide 33. Then, it is guided to the discharge target position 38 along the guide surface 33a. In the arrangement configuration of the present embodiment, the front end of the printing plate 3 delivered from the recording drum 10 does not hit the guide surface 33a of the lower guide 33 at a large incident angle, so that the guide surface 32a is a flat surface. It ’s enough.

  As described above, in the present embodiment, first, the discharge target position 38 is provided below the first tangential plane 81, and the printing plate 3 is fed along the first tangential plane 81 from the circumferential surface of the rotating recording drum 10. The control unit 90 controls the drum rotating motor 15 so that the tip of the drum reaches the discharge target position 38 while dropping downward due to gravity. However, since the discharge target position 38 is a contact line between the pair of discharge rollers 36 and 37, the discharge target position 38 is very narrow. Even when such control is performed, the leading edge of the printing plate 3 reaches a position slightly above and below the discharge target position 38. It is assumed that Therefore, a guide portion 31 having an upper guide 32 and a lower guide 33 is provided so that the leading edge of the printing plate 3 that is displaced with respect to the discharge target position 38 is guided to the discharge target position 38.

  The discharge target position 38 is a contact line between the pair of discharge rollers 36 and 37, and the second contact plane 39 is in contact with both the discharge rollers 36 and 37 at the contact line. In other words, the second tangent plane 39 is a common tangent plane that passes through the contact lines of the pair of discharge rollers 36 and 37, and is indicated by a two-dot chain line in FIGS.

  When the printing plate 3 delivered from the recording drum 10 reaches the discharge target position 38 along the second tangential plane 39, the printing plate 3 is sandwiched between the pair of discharge rollers 36 and 37 most smoothly. The guide portion 31 is for guiding the front end of the plate 3 to the discharge target position 38, but more preferably guides the plate 3 to the discharge target position 38 so as to approach the second tangential plane 39. Specifically, the arrangement is such that the proximal end portions (the end portions closer to the discharge target position 38) of the upper guide 32 and the lower guide 33 of the guide portion 31 are as close as possible to the second tangential plane 39. . As a result, the front end of the printing plate 3 is smoothly sandwiched between the pair of discharge rollers 36 and 37, and mechanical damage to the printing plate 3 can be prevented and occurrence of collision noise can be suppressed.

  As shown in FIG. 5, the discharge unit 30 includes a roller rotation motor 35 that rotates one of the pair of discharge rollers 36 and 37. FIG. 7 is a view showing a rotation driving mechanism of the discharge roller 37. The rotation shaft of the roller rotation motor 35 and the rotation shaft of the discharge roller 37 are connected by a timing belt 44. A one-way clutch 41 is inserted on the rotation shaft of the discharge roller 37. The one-way clutch 41 is a clutch mechanism that transmits a rotational force only in one of a clockwise direction and a counterclockwise direction. Note that the other discharge roller 36 is not provided with an active rotation drive mechanism, and is rotatably installed.

  In the present embodiment, the one-way clutch 41 transmits the rotational force of the roller rotation motor 35 to the discharge roller 37 only when the roller rotation motor 35 rotates the discharge roller 37 in the direction in which the printing plate 3 is discharged. Therefore, the roller rotation motor 35 cannot rotate the discharge roller 37 in the direction opposite to the discharge direction of the printing plate 3. This means that when viewed from the discharge roller 37 side, the plate 3 can be freely rotated in the discharge direction regardless of the operation of the roller rotation motor 35. That is, one discharge roller 37 and the roller rotation motor 35 are connected via a one-way clutch 41 that freely rotates the discharge roller 37 in the direction in which the printing plate 3 is discharged regardless of the operation of the roller rotation motor 35. ing.

  When the feeding of the printing plate 3 from the recording drum 10 is started, that is, at the stage where the front end of the printing plate 3 does not reach the discharge unit 30 (state in FIG. 5), the roller rotation motor 35 discharges the printing plate 3. The discharge roller 37 is rotated. At this time, the peripheral speed of the discharge roller 37 is slightly slower than the discharge speed of the printing plate 3. Specifically, the discharge speed of the printing plate 3 is the peripheral speed of the recording drum 10, and the controller 90 controls the roller rotation motor 35 so that the peripheral speed of the discharge roller 37 is slightly slower than the peripheral speed of the recording drum 10. Control. As the discharge roller 37 rotates, the discharge roller 36 in contact with the discharge roller 37 also rotates in the discharge direction of the printing plate 3.

  Next, the control unit 90 stops the rotation of the roller rotation motor 35 immediately before the front end of the printing plate 3 reaches the discharge target position 38, for example, when the front end of the printing plate 3 reaches the guide unit 31. Since the roller rotation motor 35 and the discharge roller 37 are connected via the one-way clutch 41, even if the roller rotation motor 35 stops rotating, the discharge roller 37 continues to rotate with inertia in the discharge direction of the printing plate 3. . However, the peripheral speed of the discharge roller 37 is slower than the discharge speed of the printing plate 3.

  Subsequently, the front end of the printing plate 3 is guided directly or by the guide portion 31 to reach a discharge target position 38 that is a contact line of the pair of discharge rollers 36 and 37, and is sandwiched between the discharge rollers 36 and 37. The printing plate 3 is sandwiched between a pair of discharge rollers 36 and 37 and discharged to the transport belt mechanism 45.

  FIG. 8 is a view showing a state in which the vicinity of the front end of the printing plate 3 is sandwiched between the discharge rollers 36 and 37. When the vicinity of the front end of the printing plate 3 shown in FIG. 8 is sandwiched between the pair of discharge rollers 36 and 37, the rear end of the printing plate 3 is held on the circumferential surface of the recording drum 10. At this stage, the roller rotation motor 35 has stopped rotating, and the printing plate 3 is discharged to the discharge unit 30 by the rotational force of the recording drum 10.

  The roller rotation motor 35 stops rotating immediately before the front end of the printing plate 3 reaches the discharge target position 38, and the pair of discharge rollers 36 and 37 continues to rotate with inertia. The front end of the printing plate 3 arrives there at a discharge speed faster than the peripheral speed of the discharge roller 37 and is sandwiched between the discharge rollers 36 and 37. Regardless of the operation of the roller rotation motor 35, the discharge roller 37 can freely rotate in the discharge direction of the plate 3, so that the plate 3 has reached a discharge speed faster than the peripheral speed of the discharge roller 37. However, the pair of discharge rollers 36 and 37 immediately rotate at a peripheral speed equal to the discharge speed. Thereby, the vicinity of the front end of the printing plate 3 can be smoothly sandwiched and discharged by the discharge rollers 36 and 37.

  Here, if the peripheral speed of the discharge roller 37 is faster than the discharge speed of the plate 3 before the front end of the printing plate 3 reaches the discharge target position 38, the printing force is applied by the rotational force of the discharge rollers 36 and 37. Stress is applied to the plate 3, which may damage the exposed surface of the plate 3. If the one-way clutch 41 is not provided, the discharge roller 37 cannot freely rotate in the discharge direction of the printing plate 3, so the peripheral speed of the discharge roller 37 is higher than the discharge speed of the printing plate 3. If it is slow, stress in the direction opposite to the above will act on the printing plate 3, and there is a risk that the exposed surface of the printing plate 3 will be damaged. When the one-way clutch 41 is not provided, it is necessary to perform difficult control in which the peripheral speed of the discharge roller 37 is completely matched with the discharge speed of the printing plate 3.

  In the present embodiment, the discharge roller 37 and the roller rotation motor 35 are connected via a one-way clutch 41, and the pair of discharge rollers 36, at a peripheral speed slower than the discharge speed of the printing plate 3 fed from the recording drum 10. 37 is rotated by inertia. Accordingly, when the leading edge of the printing plate 3 reaches the discharge target position 38, the pair of discharge rollers 36 and 37 immediately rotate at a peripheral speed equal to the discharge speed of the printing plate 3. Therefore, the plate 3 can be smoothly sandwiched between the discharge rollers 36 and 37 and discharged without applying unnecessary stress to the plate 3.

  The printing plate 3 sandwiched between the pair of discharge rollers 36 and 37 and discharged from the discharge target position 38 is sent out toward the transport belt mechanism 45 along the second tangential plane 39. At the stage where the vicinity of the front end of the printing plate 3 is discharged from the discharge target position 38, the printing plate 3 is conveyed only by the rotational force of the recording drum 10.

  The conveyor belt mechanism 45 is configured by a conveyor belt 47 being stretched around a plurality of conveyor rollers (see FIG. 1). The plurality of transport rollers are rotationally driven by a drive mechanism (not shown), and the transport belt 47 rotates accordingly. The conveyor belt mechanism 45 places the plate 3 on the conveyor belt 47 and discharges it.

  As shown in FIGS. 5 and 8, among the plurality of transport rollers of the transport belt mechanism 45, the leading transport roller 46 (closest to the pair of discharge rollers 36 and 37) has a peripheral surface in contact with the second tangential plane 39. It is provided as follows. If the transport roller 46 is provided so that the peripheral surface of the transport roller 46 protrudes above the second tangential plane 39, the tip of the printing plate 3 discharged along the second tangential plane 39 is The plate 3 may collide with the transport roller 46 and the plate 3 may be damaged. On the contrary, when the transport roller 46 is provided so that the peripheral surface of the transport roller 46 is larger than the second tangential plane 39, the pair of discharge rollers 36, 37 is moved to the second tangential plane 39. There is a possibility that the printing plate 3 discharged along the belt cannot come into contact with the conveyance roller 46 and the conveyance belt mechanism 45 may interfere with conveyance of the printing plate 3. Further, when the rear end of the printing plate 3 is separated from the recording drum 10, the entire printing plate 3 rotates clockwise on the paper surface of FIGS. There is also a concern that the exposure surface in the vicinity of the rear end may come into contact with the upper guide 32 of the guide portion 31 to cause a problem.

  If the transport roller 46 is provided so that the peripheral surface of the transport roller 46 is in contact with the second tangential plane 39 as in this embodiment, the pair of discharge rollers 36 and 37 does not occur as described above. Thus, the plate 3 fed along the second tangential plane 39 can be smoothly discharged by the transport belt mechanism 45.

  Next, when the printing plate 3 is further fed out from the peripheral surface of the recording drum 10, the rear end of the printing plate 3 is eventually separated from the recording drum 10. At this time, the squeegee roller 18 is separated from the peripheral surface of the recording drum 10 and the front end clamp 11 releases the clamping of the printing plate 3. Further, the recording drum 10 stops rotating. As a result, the entire plate 3 is separated from the recording drum 10 and discharged to the discharge unit 30.

  FIG. 9 is a diagram showing a state in which the vicinity of the rear end of the printing plate 3 has been sent out from the recording drum 10. In FIG. 9, for convenience of illustration, the squeegee roller 18 is brought into contact with the peripheral surface of the recording drum 10 to show the first tangential plane 81. When the front end clamp 11 releases the clamping of the printing plate 3 and the rear end of the printing plate 3 is separated from the circumferential surface of the recording drum 10, the rotation of the recording drum 10 is stopped and the rotation of the discharge roller 37 is resumed. In addition, the control unit 90 controls the drum rotation motor 15 and the roller rotation motor 35. Then, the printing plate 3 is discharged to the transport belt mechanism 45 by the rotational force of the discharge roller 37.

  Further, the vicinity of the front end of the printing plate 3 sent out from the discharge target position 38 reaches the transport belt mechanism 45 and is placed on the transport belt 47 and transported. Eventually, the vicinity of the rear end of the printing plate 3 is also sent out from the discharge target position 38, and the entire printing plate 3 is discharged from the discharge unit 30 by the conveying belt mechanism 45. As described above, an image recording process is performed on the printing plate 3, and the printing plate 3 is discharged from the image recording apparatus 1.

  In the present embodiment, the discharge target position 38 is provided below the first tangential plane 81 that is the tangential plane of the squeegee roller 18 at the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10, and rotates. The control unit 90 controls the drum rotation motor 15 so that the front end of the printing plate 3 fed out from the circumferential surface of the recording drum 10 along the first tangent plane 81 reaches the discharge target position 38 while dropping downward due to gravity. Yes. Since the discharge target position 38 is provided below the first tangential plane 81 and the exposed plate 3 is discharged by utilizing the fact that the front end of the plate 3 hangs down due to gravity, a simple apparatus configuration is used. The printing plate 3 can be discharged. As a result, the number of drive parts necessary for discharging the printing plate 3 is also minimal (in the image recording apparatus 1, only the roller rotation motor 35 that rotates the discharge roller 37), which increases the manufacturing cost of the image recording apparatus 1. Can be suppressed.

  In this embodiment, the plate 3 is guided to the discharge target position 38 by utilizing the fact that the tip of the plate 3 hangs down due to gravity. Although there is a difference in the degree of deflection due to gravity depending on the rigidity of the printing plate 3, the tip fed from the peripheral surface of the recording drum 10 hangs down due to gravity in any printing plate 3. The degree of deflection can be adjusted by the rotational speed of the recording drum 10, and various types of the printing plate 3 can be guided to the discharge target position 38 by the control unit 90 controlling the drum rotation motor 15. Therefore, the image recording apparatus 1 can reliably discharge the printing plate 3 regardless of the type of the printing plate 3.

  However, the discharge target position 38 is a very narrow target because it is a contact line between the pair of discharge rollers 36 and 37, and even if the control unit 90 controls the rotational speed of the recording drum 10, the leading edge of the plate 3 is not touched. It is also assumed that the target position 38 is shifted slightly above and below the target discharge position 38. For this reason, a guide portion 31 having an upper guide 32 and a lower guide 33 is provided so that the leading edge of the printing plate 3 that is displaced with respect to the discharge target position 38 is guided to the discharge target position 38. Thereby, the image recording apparatus 1 can discharge the printing plate 3 from the discharge unit 30 more reliably. Preferably, the guide portion 31 guides the printing plate 3 to the discharge target position 38 so as to approach the second tangential plane 39 that is a common tangent plane of both contact lines of the pair of discharge rollers 36 and 37.

  While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention. For example, in the above embodiment, the upper guide 32 of the guide portion 31 is bent, but it may be bent as shown in FIG. The upper guide 132 of the guide portion 31 shown in FIG. 10 has a guide surface 132a that is curved so as to bulge upward. The lower guide 33 has a flat guide surface 33a as in the above embodiment. The front end of the printing plate 3 sent out from the circumferential surface of the recording drum 10 and directed upward from the discharge target position 38 reaches the guide surface 132a of the upper guide 132 and is guided to the discharge target position 38 along the guide surface 132a. It is burned. Even when the upper guide 132 has a curved shape as shown in FIG. 10, the impact of the plate 3 against the guide surface 132a of the upper guide 132 is alleviated, and the plate 3 is damaged due to the impact and the occurrence of a collision sound. Can be prevented.

  In the above embodiment, the squeegee roller 18 is provided on the upper left side of the recording drum 10 on the paper surface of each figure, and the discharge target position 38 is set on the upper right side of the contact line between the squeegee roller 18 and the recording drum 10. These arrangement relationships may be as shown in FIG. 11 or FIG. In the example of FIG. 11, a squeegee roller 18 is provided immediately above the recording drum 10. Therefore, the first tangential plane 81 that is the tangential plane of the squeegee roller 18 at the contact line between the squeegee roller 18 and the plate 3 held on the recording drum 10 is a horizontal plane. The discharge target position 38 of the discharge unit 30 is set below the first tangential plane 81. As a result, as shown in FIG. 11, a discharge target position 38 is set on the lower right side of the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10. Even in such an arrangement relationship, the discharge target position 38 is provided below the first tangent plane 81 as in the above-described embodiment, so that the first tangential plane 81 extends from the circumferential surface of the recording drum 10. The tip of the printing plate 3 sent out along the line reaches the discharge target position 38 while gradually dropping downward due to gravity.

  On the other hand, in the example of FIG. 12, a squeegee roller 18 is provided on the upper right side of the recording drum 10 on the paper surface. Therefore, the first tangential plane 81 that is the tangential plane of the squeegee roller 18 at the contact line between the squeegee roller 18 and the plate 3 held on the recording drum 10 is an inclined surface that is inclined from the upper left to the lower right on the paper surface. The discharge target position 38 of the discharge unit 30 is set below the first tangential plane 81. As a result, as shown in FIG. 12, the discharge target position 38 is set on the lower right side of the contact line between the squeegee roller 18 and the printing plate 3 held on the recording drum 10. Even in such an arrangement relationship, the discharge target position 38 is provided below the first tangent plane 81 as in the above-described embodiment, so that the first tangential plane 81 extends from the circumferential surface of the recording drum 10. The tip of the printing plate 3 sent out along the line reaches the discharge target position 38 while gradually dropping downward due to gravity.

  In short, various arrangements are possible as long as the discharge target position 38 is provided below the first tangential plane 81 that is the tangential plane of the squeegee roller 18 in the contact line between the squeegee roller 18 and the plate 3 held on the recording drum 10. A relationship is possible. Then, the control unit 90 causes the drum rotation motor 15 so that the tip of the printing plate 3 fed along the first tangential plane 81 from the peripheral surface of the rotating recording drum 10 reaches the discharge target position 38 while dropping downward due to gravity. Should be controlled.

  In the above embodiment, the controller 90 controls the roller rotation motor 35 so that the peripheral speed of the discharge roller 37 is slightly slower than the discharge speed of the printing plate 3, but the length of the printing plate 3 is short. In some cases, the recording drum 10 may start to decelerate before the leading edge of the plate 3 reaches the discharge target position 38. In this case, the discharge speed of the printing plate 3 is also reduced, and the peripheral speed of the discharge roller 37 is faster than the discharge speed of the printing plate 3 when the leading edge of the printing plate 3 reaches the discharge target position 38. There is also. Then, stress is applied to the printing plate 3 by the rotational force of the discharge rollers 36 and 37, and there is a possibility that the exposed surface of the printing plate 3 is damaged. Therefore, when the length of the printing plate 3 is shorter than a predetermined value, the maximum reaching speed itself of the recording drum 10 is slowed down, and the peripheral speed of the discharge roller 37 is slightly slower than the discharge speed of the corresponding printing plate 3. What should I do? The maximum arrival speed is a speed at which the front end of the printing plate 3 can reach the discharge target position 38 before the recording drum 10 starts decelerating.

DESCRIPTION OF SYMBOLS 1 Image recording device 3 Printing plate 10 Recording drum 15 Drum rotation motor 18 Squeeze roller 20 Supply part 30 Discharge part 31 Guide part 32,132 Upper guide 32a, 33a, 132a Guide surface 33 Lower guide 35 Roller rotation motor 36,37 Discharge roller 38 discharge target position 39 second tangent plane 41 one-way clutch 45 conveyance belt mechanism 46 conveyance roller 50 recording head 81 first tangential plane 90 control unit

Claims (12)

An image recording apparatus for recording an image on a sheet-like recording medium,
A cylindrical recording drum that is rotatably provided and wraps and holds a recording medium around a cylindrical peripheral surface;
A drum rotating unit that rotates the recording drum around the center axis of the cylindrical shape;
A rotation control unit for controlling rotation of the recording drum;
A supply unit for supplying a recording medium to the circumferential surface of the recording drum;
An image recording unit for recording an image on a recording medium held on the circumferential surface of the recording drum;
A discharge unit that receives and discharges a recorded recording medium fed from the circumferential surface of the recording drum;
A cylindrical squeegee roller provided in parallel with the central axis of the recording drum so as to be able to contact with and separate from the peripheral surface of the recording drum;
With
The discharge unit has a discharge target position below a first tangential plane that is a tangential plane of the squeegee roller at both contact lines when the squeegee roller is in contact with the recording medium held on the recording drum. Set,
The rotation control unit reaches the discharge target position while a front end of a recording medium which is separated from the peripheral surface of the rotating recording drum by the contact line and is sent along the first tangential plane hangs down due to gravity. An image recording apparatus characterized by controlling the drum rotating unit. The image recording apparatus according to claim 1,
A squeegee roller moving mechanism for moving the squeegee roller between a contact position where the recording medium held on the recording drum and the squeegee roller contact each other and a separation position where the recording medium held on the recording drum and the squeegee roller are separated from each other. In addition,
The image recording apparatus according to claim 1, wherein the contact position of the squeegee roller is located at a specific coordinate position with a central axis of the recording drum as a coordinate origin. The image recording apparatus according to claim 1 or 2,
An image recording apparatus comprising: a guide portion that guides a leading end of a recording medium fed from a peripheral surface of the recording drum to the discharge target position in the discharge portion. The image recording apparatus according to claim 3.
The guide part is
An upper guide that guides a recording medium heading above the discharge target position to the discharge target position;
A lower guide for guiding a recording medium heading below the discharge target position to the discharge target position;
An image recording apparatus comprising: The image recording apparatus according to claim 4, wherein
The image recording apparatus according to claim 1, wherein the upper guide has a guide surface curved so as to bulge upward. The image recording apparatus according to claim 4, wherein
The image recording apparatus according to claim 1, wherein the upper guide has a guide surface bent so as to protrude upward. The image recording apparatus according to any one of claims 3 to 6,
The discharge portion includes a pair of cylindrical discharge rollers that are in contact with each other on the circumferential surface,
The discharge target position is set to a contact line of the pair of discharge rollers,
The image recording apparatus according to claim 1, wherein the recording medium that has reached the discharge target position is discharged while being sandwiched between the pair of discharge rollers. The image recording apparatus according to claim 7, wherein
The discharge unit further includes a roller rotation unit that rotates one discharge roller of the pair of discharge rollers,
The one discharge roller and the roller rotation unit are connected via a one-way clutch that freely rotates the one discharge roller in the direction in which the recording medium is discharged regardless of the operation of the roller rotation unit. An image recording apparatus. The image recording apparatus according to claim 8.
The image recording apparatus according to claim 1, wherein the roller rotating unit rotates the one discharge roller so that a peripheral speed of the pair of discharge rollers is slower than a speed of the recording medium fed from the recording drum. The image recording apparatus according to any one of claims 7 to 9,
The image recording apparatus according to claim 1, wherein the guide portion is provided to guide the recording medium to the discharge target position so as to approach a second tangential plane that is a common tangential plane in a contact line of the pair of discharge rollers. In the image recording device according to any one of claims 7 to 10,
The discharge unit further includes a transport roller for transporting the recording medium discharged by the pair of discharge rollers,
The image recording apparatus according to claim 1, wherein the conveying roller is provided such that a peripheral surface thereof is in contact with the second tangential plane. The image recording apparatus according to any one of claims 1 to 11,
The image recording apparatus according to claim 1, wherein a supply line of the recording medium by the supply unit is provided above the first tangential plane.

Images