JP2007064994A - Image recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording device capable of moving a balance weight with a small torque, upon adjusting the center of gravity and also reliably preventing the balance weight from moving upon recording an image, while being a simple configuration. <P>SOLUTION: The device is equipped with a guide groove 31, having an opening formed on both end faces of a recording drum 11 along the circumference with the rotation axis as the center, a pair of balance weights 32 partially including a magnet and movable along the guide groove 31, a cap member made of iron, partially covering the opening of the guide groove 31, a moving mechanism 17 which moves each balance weight 32, from the position where the weight that is in tight contact with the cap member 81 to the position where the weight is separated from the cap member 81, and a control means which moves the balance weight 3 along the guide groove 31 by making the recording drum 11 rotate, while the moving mechanism 17 presses the balance weight 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image recording apparatus that records an image by irradiating an image recording material such as a printing plate mounted on a recording drum with a light beam.

  Such an image recording apparatus includes a cylindrical recording drum for mounting an image recording material on an outer peripheral surface thereof, and a rotation drive mechanism that rotates the recording drum around a rotation shaft disposed on an axis thereof. And a recording head that emits a light beam modulated in accordance with the image signal. In such an image recording apparatus, while rotating the recording drum at a high speed, the recording head irradiates the image recording material mounted on the outer peripheral surface of the recording drum with a light beam, and the recording head is used as the rotation axis of the recording drum. By moving in a parallel direction, a desired image is recorded on the image recording material.

  By the way, in such an image recording apparatus, image recording materials of various sizes are mounted on the recording drum. Further, in such an image recording apparatus, the image recording material is mounted on the outer peripheral surface of the recording drum by fixing both ends of the image recording material to the outer periphery of the recording drum using a clamp mechanism. The arrangement of the clamp mechanism is changed according to the size of the image recording material. For this reason, the position of the center of gravity of the recording drum after mounting the image recording material varies depending on the size of the image recording material mounted on the outer peripheral surface of the recording drum.

  On the other hand, in order to record an image at a high speed, it is necessary to rotate the recording drum itself at a high speed. At this time, if the position of the center of gravity of the recording drum after mounting the image recording material is not arranged near the rotation axis, forced vibration occurs in the recording drum during high-speed rotation, and not only the image cannot be recorded accurately, The problem arises that the device itself is damaged.

  For this reason, Patent Document 1 proposes an image recording apparatus provided with a counterweight composed of a plurality of permanent magnets that can be moved and fixed along a circumference around the rotation axis of the recording drum. ing. According to the image recording apparatus described in Japanese Patent No. 2977550, the position of the center of gravity of the recording drum after mounting the image recording material is adjusted on the outer peripheral surface of the recording drum by adjusting the positions of the plurality of counterweights. Regardless of the size of the image recording material to be mounted, it can be disposed near the rotation axis of the recording drum, and the recording drum can be rotated at high speed without causing vibration.

Further, in Patent Document 2, an index plate having a plurality of engagement holes formed at a predetermined angle θ along a circumference centered on the rotation axis of the recording drum, and engageable with the engagement holes. An image recording apparatus is disclosed in which a counterweight is fixed by a positioning pin.
Patent No. 2977550 JP 2002-82447 A

  When adopting a configuration in which a counterweight is attached to the recording drum by magnetic force as in the image recording apparatus described in Patent Document 1, the recording drum is accelerated with a large acceleration force at the start or end of image recording. In order to prevent the counterweight from moving when decelerated, it is necessary to use a counterweight having a strong magnetic force. For this reason, when the counterweight is moved with a predetermined frictional force with respect to the recording drum in order to adjust the position of the center of gravity, there arises a problem that a large torque is required to overcome the frictional force due to the magnetic force. Further, since the counterweight slides on the surface of the recording drum, there arises a problem that the holding force changes due to wear.

  On the other hand, although the image recording apparatus described in Patent Document 2 can solve such a problem, there arises a problem that the number of parts of the counterweight increases. In addition, the position where the weight can be fixed becomes discontinuous and cannot be fixed at an arbitrary position.

  The present invention has been made in order to solve the above-mentioned problems. Although the configuration is simple, the balance weight can be moved with a small torque when adjusting the position of the center of gravity, and the balance weight can be used when recording an image. It is an object of the present invention to provide an image recording apparatus that can reliably prevent the movement of the lens and that does not change the holding force due to wear.

  The invention according to claim 1 is an image recording apparatus for recording an image by irradiating an image recording material mounted on a recording drum with a light beam, and an outer peripheral surface for mounting the image recording material; A cylindrical recording drum having an end surface made of a non-magnetic material, a rotational drive mechanism for rotating the recording drum around a rotation shaft disposed on an axis thereof, and an end surface of the recording drum, A guide groove having an opening formed along a circumference around the rotation axis, a pair of counterweights including a magnet at least in part and movable along each guide groove, and a magnetic An annular lid member made of a body material and covering a part of the opening of the guide groove on the end surface of the recording drum, the balance weight being in close contact with each other, and the balance weights being in close contact with the lid member The lid member from the position to be A moving mechanism that presses and moves in the direction of the recording drum to a position separated from the recording drum, and the recording drum is rotated by the rotational drive mechanism in a state where the moving mechanism presses the counterweight, thereby And a control means for moving the weight along the guide groove.

  According to a second aspect of the present invention, in the first aspect of the invention, each of the counterweights has a plurality of convex portions that come into contact with the bottom portion of the guide groove, and the convex portion is a bottom portion of the guide groove. It is comprised from resin with a small friction coefficient between.

  According to a third aspect of the present invention, in the first aspect of the invention, a sensor is provided for detecting the arrangement of the counterweights with respect to the recording drum.

  According to the first aspect of the present invention, the balance weight can be moved with a small torque at the time of adjusting the position of the center of gravity, and the movement of the balance weight can be reliably performed at the time of image recording. Can be prevented. Further, the counterweight can be fixed at an arbitrary position.

  According to the second aspect of the present invention, it is possible to more smoothly execute the movement of the counterweight when adjusting the position of the center of gravity with a small torque.

  According to the invention described in claim 3, it is possible to confirm the position of the counterweight.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a part of an outline of an image recording apparatus to which the present invention is applied, and FIG. 2 is a schematic front view thereof.

  This image recording apparatus includes a cylindrical recording drum 11, a recording head 12, a punch unit 13, a photosensitive material supply / discharge unit 14, and an electrical unit 15.

  The recording drum 11 is for mounting the printing plate 10 on the outer peripheral surface thereof, and includes a front end clamp 21 for fixing the front end portion of the printing plate 10 and a rear end for fixing the rear end of the printing plate 10. A clamp 22 and a suction hole (not shown) for sucking the back surface of the printing plate 10 are provided. The recording drum 11 is made of aluminum which is a nonmagnetic material.

  The front end clamp 21 is rotated between a position at which the front end of the printing plate 10 is fixed and a position at which the front end is released by rotating about the shaft 23 (see FIG. 2) by the action of the front end clamp opening / closing mechanism 24. Further, the rear end clamp 22 is separated from the recording drum 11 by a position at which the rear end of the printing plate 10 is fixed on the surface of the recording drum 11 by the action of the rear end clamp opening / closing mechanism 25 and opens the rear end of the printing plate 10. Move between positions.

  In addition, the recording drum 11 rotates around a rotation shaft 26 disposed on the axis thereof by driving a rotation driving mechanism 16 described later. On both end faces of the recording drum 11, a guide groove 31 formed along the circumference centering on the rotation shaft 26 and a pair of counterweights 32 movable along the guide groove 31 are disposed. Yes. The configuration of the guide groove 31 and the counterweight 32 will be described in detail later.

  The recording head 12 includes a plurality of light emitting elements (not shown), and irradiates the printing plate 10 mounted on the outer peripheral surface of the recording drum 11 with a light beam modulated in accordance with an image signal. This is for forming an image on top. The recording head 12 is fixed on the moving table 38. The moving table 38 is screwed with a feed screw 37 that is rotated by driving of the motor 36. Therefore, the recording head 12 is configured to reciprocate in a direction parallel to the rotation shaft 26 of the recording drum 11 by driving the motor 36.

  The punch unit 13 is for punching a positioning punch hole or a punch hole for mounting on a printing drum or the like on the printing plate 10 before mounting on the outer peripheral surface of the recording drum 11. Yes, with a pair of left and right punches 35.

  The photosensitive material supply unit 14 includes an upper tray 33 and a lower tray 34. The unused printing plate 10 is placed on the lower tray 34. The printing plate 10 placed on the lower tray 34 is once transported to the punch unit 13, and a punching hole for positioning is formed at the tip thereof, and then placed again on the lower tray 34. . The printing plate 10 is conveyed from the lower tray 34 to the recording drum 11, mounted on the outer peripheral surface of the recording drum 11 to record an image, and then discharged onto the upper tray 33.

  FIG. 3 is a side view showing the recording drum 11 together with the rotational driving mechanism 16 for rotationally driving the recording drum 11, the moving mechanism 17 for moving the counterweight 32 described above, and the like.

  The rotational drive mechanism 16 for rotationally driving the recording drum 11 includes a pulley 41 fixed to the rotational shaft 26 of the recording drum 11 that is pivotally supported by a bearing 39, and a belt 42 and a pulley 43 with respect to the pulley 41. Connected to the motor 44. A rotary encoder 45 is disposed on the rotating shaft 26 of the recording drum 11, and the rotational angle position of the recording drum 11 is constantly monitored by the rotary encoder 45.

  The motor 44 and the rotary encoder 45 in the rotation drive mechanism 16 are connected to the control unit 46. The control unit 46 is connected to an input unit 47 having an input device such as a keyboard. The control unit 46 is also connected to a moving mechanism 17 (described later) for moving the counterweight 32.

  FIG. 4 is a perspective view showing the moving mechanism 17 together with a pair of counterweights 32 disposed in the guide groove 31 of the recording drum 11.

  As shown in this figure, a guide groove 31 having an opening formed along a circumference around the rotation shaft 26 shown in FIG. 1 is formed on the end surface of the recording drum 11. A pair of counterweights 32 are disposed in the 31. Further, the moving mechanism 17 is disposed at a position facing both left and right edges of the recording drum 11.

  FIG. 5 is an enlarged perspective view showing the moving mechanism 17 together with the recording drum 11 and the like, and FIGS. 6 and 7 are side views of the moving mechanism 17. 5 illustrates the moving mechanism 17 disposed on the left end side of the recording drum 11 illustrated in FIG. 4, and FIGS. 6 and 7 illustrate the movement mechanism 17 disposed on the right end side of the recording drum 11 illustrated in FIG. The moved moving mechanism 17 is illustrated. 6 shows a state in which the counterweight 32 is not pressed by the pressing portion 52 in the moving mechanism 17, and FIG. 7 shows a state in which the counterweight 32 is pressed by the pressing portion 52 in the moving mechanism 17. . The pair of moving mechanisms 17 and 17 have a symmetrical configuration.

  These moving mechanisms 17 are each provided with an arm 54 having a U-shaped groove formed at the tip thereof and capable of rotating about a support shaft 53 supported by a support member 50. The arm 54 is urged counterclockwise in FIGS. 6 and 7 by the action of a spring 55 connected to the opposite side of the U-shaped groove. The moving mechanism 17 includes a motor 56 (see FIG. 5). The motor 56 biases the arm 54 in the clockwise direction in FIGS. 6 and 7.

  Further, the moving mechanism 17 includes a driving member 57 having a pressing portion 52 at the tip thereof. The drive member 57 is supported by the guide member 58 so as to be movable in the horizontal direction. An engagement pin 59 is provided upright at the base end of the drive member 57. The engaging pin 59 is engaged with a U-shaped groove formed at the tip of the arm 54.

  In the moving mechanism 17 configured in this manner, when the arm 54 rotates clockwise about the support shaft 53 from the state shown in FIG. 6 by driving the motor 56, the drive member 57 is interposed via the engagement pin 59. And is moved in the direction of the counterweight 32 in the recording drum 11 (the left direction shown in FIGS. 6 and 7), and the counterweight 32 is pressed by the pressing portion 52 at the tip as shown in FIG. To do.

  A sensor 61 is attached to one end of the guide member 58 via a bracket 62. This sensor 61 is used to detect a sensor dog 63 of a counterweight 32 described later.

  Next, the configuration of the counterweight 32 will be described. 8 is a perspective view of the counterweight 32, FIG. 9 is a front view thereof, and FIG. 10 is a side view thereof.

  The counterweight 32 includes a weight body 71 made of brass, a resin contact member 72 attached to both sides of the weight body 71, and the sensor dog 63 described above. Each contact member 72 is formed with a pair of convex portions 77 that can contact the bottom of the guide groove 31 formed in the recording drum 11. The contact member 72 is made of a resin having a small coefficient of dynamic friction with the bottom of the aluminum guide groove 31. Moreover, the recessed part 76 which has a shape corresponding to the press part 52 in the moving mechanism 17 mentioned above is formed in the center part of the weight main body.

  In the upper part of the counterweight 32, a permanent magnet 73, a pair of iron plates 74 arranged so as to sandwich the permanent magnet 73, and an aluminum as a nonmagnetic material for fixing the permanent magnet 73 and the iron plate 74. A lid 75 made of metal is disposed. Since the pair of iron plates 74 is disposed so as to sandwich the permanent magnet 73 and is configured only by a non-magnetic material, an annular magnetic field is generated by the permanent magnet 73 and a strong magnetic force is obtained. ing.

  FIGS. 11 and 12 are explanatory views showing a state in which the counterweight 32 is housed in the guide groove 31 formed in the recording drum 11. 11 shows a state where the counterweight 32 is not pressed by the pressing portion 52 in the moving mechanism 17, and FIG. 12 shows a state where the counterweight 32 is pressed by the pressing portion 52 in the moving mechanism 17. .

  As described above, the guide grooves 31 having openings formed along the circumference around the rotation shaft 26 are formed on both end faces of the recording drum 11. As shown in FIGS. 5, 11, and 12, an annular lid member 81 that covers a part of the opening of the guide groove 31 is disposed on both end surfaces of the recording drum 11. The lid member 81 is made of a magnetic material such as iron, and is in a position facing the permanent magnet 73 and the iron plate 74 of the counterweight 32 when the counterweight 32 is housed in the guide groove 31. Has been placed.

  For this reason, as shown in FIG. 11, when the counterweight 32 is not pressed by the pressing portion 52 in the moving mechanism 17, the permanent magnet 73 and the iron plate 74 of the counterweight 32 are caused by the magnetic force of the permanent magnet 73. The counterweight 81 is in close contact with the lid member 81, and the counterweight 32 is fixed in the guide groove 31 in the recording drum 11. At this time, even when the recording drum 11 is accelerated or decelerated with a large acceleration force at the start or end of image recording, the counterweight 32 is covered with a strong magnetic force sufficient to prevent the counterweight 32 from moving. The member 81 is closely attached.

  On the other hand, as shown in FIG. 12, in a state where the counterweight 32 is pressed by the pressing portion 52 in the moving mechanism 17, the permanent magnet 73 and the iron plate 74 of the counterweight 32 are separated from the lid member 81, A total of four convex portions (see FIGS. 8 and 10) of each abutting member 72 in the weight 32 abut against the bottom portion of the guide groove 31 formed in the recording drum 11.

  When the recording drum 11 rotates in this state, the movement of the counterweight 32 is restricted by the pressing portion 52 of the moving mechanism 17, so that the counterweight 32 moves in the guide groove 31 with respect to the recording drum 11. Move relatively. At this time, the permanent magnet 73 and the iron plate 74 of the counterweight 32 are separated from the lid member 81. The counterweight 32 and the bottom of the guide groove 31 are in contact with each other via four convex portions made of a resin having a small dynamic friction coefficient between the bottom of the guide groove 31 made of aluminum. For this reason, the counterweight 32 can be moved with a small torque.

  Next, in the image recording apparatus configured as described above, the position adjustment operation of the balance weight 32 for moving the balance weight 32 to a desired position in consideration of the position of the center of gravity of the recording drum 11 will be described. FIG. 13 is a flowchart showing the position adjusting operation of the counterweight 32. In order to adjust the position of the pair of counterweights 32, the flow shown in FIG. 13 is executed for each counterweight 32.

  When executing the positioning operation of the counterweight 32, the position where the counterweight 32 should be arranged is calculated based on the size of the printing plate 10 that is next mounted on the recording drum 11 and on which an image is recorded ( Step S1).

  Then, the position of the counterweight 32 after calculation is compared with the position where the counterweight 32 is currently arranged (step S2). If the position of the counterweight 32 after calculation matches the position where the counterweight 32 is currently arranged, the positioning operation is terminated because there is no need to execute the positioning operation of the counterweight 32. .

  On the other hand, when the position of the counterweight 32 after calculation does not match the position where the counterweight 32 is currently disposed, the positioning operation of the counterweight 32 is executed (step S3).

  When positioning the counterweight 32, first, the recording drum 11 is rotated by driving the motor 44 in the rotational drive mechanism 16, and as shown in FIGS. 5 and 6, of the pair of counterweights 32, The concave portion 76 of the counterweight 32 to be moved first and the pressing portion 52 in the moving mechanism 17 are arranged to face each other. Next, as shown in FIG. 7, the pressing portion 168 in the moving mechanism 17 is moved in the direction of the counterweight 32. Accordingly, as shown in FIG. 12, the permanent magnet 73 and the iron plate 74 in the counterweight 32 are separated from the lid member 81, and the counterweight 32 can move along the guide groove 31.

  In this state, the recording drum 11 is rotated by driving the motor 44 in the rotation driving mechanism 16, and the counterweight 32 is moved to a desired position with respect to the recording drum 11. At this time, the counterweight 32 is separated from the lid member 81, and the guide groove 31 is provided via four convex portions made of a resin having a small coefficient of dynamic friction with the bottom of the guide groove 31. Since it is in contact with the bottom, the counterweight 32 can be moved with a small torque. For this reason, a large torque is not required to rotate the recording drum 11.

  When the counterweight 32 moves to a desired position, the pressing portion 52 in the moving mechanism 17 is separated from the counterweight 32 as shown in FIGS. Accordingly, as shown in FIG. 11, the permanent magnet 73 and the iron plate 74 of the counterweight 32 are in close contact with the lid member 81, and the counterweight 32 is fixed at this position.

  When the positioning operation of the counterweight 32 is completed, the position detection operation of the counterweight 32 is executed in order to confirm whether or not the counterweight 32 is fixed at a desired position (step S4). In this position detection operation, the recording drum 11 is rotated by driving the motor 44 in the rotation drive mechanism 16, and the sensor dog 63 of the counterweight 32 is detected by the sensor 61 shown in FIGS. 6 and 7, and the rotary encoder at that time is detected. This is performed by detecting 45 signals.

  If the detected position of the counterweight 32 is different from the position where the counterweight 32 should be disposed, or the position of the counterweight 32 deviates more than the allowable range from the position where the counterweight 32 should be disposed. If so, the positioning operation (step S3) and the position detection operation (step S4) of the counterweight 32 are repeated again (step S5).

  On the other hand, when the detected position of the counterweight 32 coincides with the position where the counterweight 32 should be arranged, or the position of the counterweight 32 is allowed from the position where the counterweight 32 should be arranged. If the position is within the range, the position data is stored (step S6), and the position adjustment operation of the counterweight 32 is terminated. Note that the guide groove 31 in which the counterweight 32 is disposed may be formed only on one end surface of the recording drum 11.

In the above embodiment, the entire recording drum 11 is made of a single material (aluminum, which is a non-magnetic material), but may be made by combining a plurality of materials. However, even in this case, at least both end surfaces of the recording drum 11 (when the guide groove 31 is formed only on one end surface, the end surface of the recording drum 11 on the side where the guide groove 31 is formed) are non-magnetic materials such as aluminum. It must be composed of materials.

In addition, the magnetic body in the above embodiment (such as the permanent magnet 73 disposed on the cover member 81 of the guide groove 31 and the counterweight 32) has magnetism at least when the counterweight 32 is fixed. That's fine. For example, the lid member 81 may be composed of an electromagnet, and when the counterweight 32 is moved along the guide groove 31, the lid member 81 may be controlled to lose its magnetism.

1 is an exploded perspective view showing an outline of an image recording apparatus to which the present invention is applied. 1 is a schematic front view of an image recording apparatus to which the present invention is applied. 3 is a side view showing a rotation drive mechanism 16 for rotating the recording drum 11 and a moving weight 17 for moving the counterweight 32 along the guide groove 31 and the like. FIG. 4 is a schematic side view showing the moving mechanism 17 together with a counterweight 32 disposed in the guide groove 31 of the recording drum 11. FIG. FIG. 3 is an enlarged perspective view showing a moving mechanism 17 together with a recording drum 11 and the like. 3 is a side view of a moving mechanism 17. FIG. 3 is a side view of a moving mechanism 17. FIG. 3 is a perspective view of a counterweight 32. FIG. 3 is a front view of a counterweight 32. FIG. 3 is a side view of a counterweight 32. FIG. 3 is an explanatory view showing a state in which a counterweight 32 is housed in a guide groove 31 formed in the recording drum 11. FIG. 3 is an explanatory view showing a state in which a counterweight 32 is housed in a guide groove 31 formed in the recording drum 11. FIG. 4 is a flowchart showing a position adjustment operation of a counterweight 32.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plate 11 Recording drum 12 Recording head 16 Rotation drive mechanism 17 Movement mechanism 26 Rotation shaft 31 Guide groove 32 Balance weight 38 Movement table 41 Pulley 42 Belt 43 Pulley 44 Motor 45 Rotary encoder 46 Control part 50 Support member 53 Support shaft 54 Arm 55 Spring 56 Motor 57 Drive member 58 Guide member 59 Engagement pin 61 Sensor 63 Sensor dog 71 Weight body 72 Contact member 73 Permanent magnet 74 Iron plate 76 Concave portion 77 Convex portion 81 Cover member

Claims (3)

An image recording apparatus for recording an image by irradiating a light beam to an image recording material mounted on a recording drum,
A cylindrical recording drum having an outer peripheral surface for mounting the image recording material and an end surface made of a non-magnetic material;
A rotation drive mechanism for rotating the recording drum around a rotation shaft disposed at its axis;
On the end surface of the recording drum, a guide groove having an opening formed along a circumference around the rotation axis;
A pair of counterweights including magnets at least in part and movable along each guide groove;
An annular lid member that is made of a magnetic material and covers a part of the opening of the guide groove on the end surface of the recording drum, to which the counterweight can be in close contact;
A moving mechanism for pressing and moving each of the counterweights in a direction toward the recording drum from a position in close contact with the lid member to a position away from the lid member;
Control means for moving the counterweight along the guide groove by rotating the recording drum by the rotational drive mechanism in a state where the moving mechanism presses the counterweight;
An image recording apparatus comprising: The image recording apparatus according to claim 1,
Each of the counterweights has an image recording apparatus including a plurality of protrusions that come into contact with the bottom of the guide groove, and the protrusions are made of a resin having a small coefficient of friction with the bottom of the guide groove. The image recording apparatus according to claim 1,
An image recording apparatus comprising a sensor for detecting an arrangement of each counterweight with respect to the recording drum.

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