JP2009190220A - Printing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compose a printing device which enables a printing of high quality by controlling the vibration of a print head even if operating the print head at a high speed. <P>SOLUTION: A bag 30 composed of a flexible material is fixed to the carriage cover 16 of a carriage 10 composing the print head H, and two or more vibration repressors Q composed of metallic leaves 31 are enclosed in the bag 30. Thereby, the vibration repressor Q controls the vibration when the print head H reaches the movement end and reverses in the state that the weight of the vibration repressor Q includes been applied to the print head H. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention discharges ink from the print head moving in the main scanning direction to the recording medium, and when the print head reaches the moving end, conveys the recording medium by a set amount in the sub scanning direction orthogonal to the main scanning direction, Thereafter, the present invention relates to a printing apparatus that moves the print head in the reverse direction, and more particularly, to a technique for suppressing vibration of the print head.

  As a printing apparatus configured as described above, there are those shown in Patent Document 1 and Patent Document 2. In Patent Document 1, by moving a pair of print heads having the same mass (an inkjet head in the literature) in the opposite direction, reaction forces generated by the reciprocating motion of the print heads can be canceled out and vibrations can be suppressed. Are listed.

  In Patent Document 2, when a carriage mounting a print head (a recording head in the literature) is moved in the main scanning direction, the carriage is moved by a conveying roller and a conveying belt for conveying the recording medium in a sub-scanning manner. It is described that vibration is suppressed by moving in the opposite direction to the carriage at the same speed as the carriage.

JP-A-8-276777 (paragraph numbers [0062] to [0089], [0152], [0153], FIG. 1 and FIG. 2) JP 2000-263870 A (paragraph numbers [0019] to [0028], [0053] FIGS. 1 and 2)

  In an ink jet type printing apparatus, the print head can be moved at a high speed, and at the moving end, the moving direction can be quickly switched and the movement can be started to shorten the printing processing time. However, when the print head that moves at high speed is stopped and moved in the opposite direction, the print head is moved before the vibration acting on the print head is attenuated to start printing. A non-uniform density region appears due to vibration at both ends, and the quality of the printed image is likely to deteriorate. Therefore, it is conceivable to use the technique disclosed in Patent Document 1 or Patent Document 2, but the structure of any of the techniques of any of the documents is complicated, and its feasibility is low in terms of increasing the size.

  The both ends of the recording medium are the positions of both ends in the moving direction (main scanning direction) of the print head. Then, the print head is moved at a high speed, and at the moving end, printing is started in a state where the vibration of the print head is not attenuated as in a printing apparatus that quickly reverses the print head to perform printing. A non-uniform density region appears in a belt shape along the vertical direction (sub-scanning direction).

  In a printing apparatus that performs printing by simply reciprocating the print head, analyzing the occurrence of vibrations in the print head, the print head that moves at high speed is stopped, and when the print head starts moving in the reverse direction, It has been confirmed that the end portion in the sub-scanning direction vibrates up and down. This phenomenon is thought to occur when the print head moving at a high speed is suddenly stopped, and the kinetic energy of the print head acts in a direction that causes vibration, and the print head immediately after the movement stops at the moving end moves at a high speed. When started, it is considered that kinetic energy acting on the print head from the outside acts in a direction that causes vibration.

  The phenomenon that the print head vibrates in this way may be affected by the support structure of the guide rail that supports the print head. However, if the support structure using the guide rail is improved, the structure will be complicated and improved. There is room for.

  An object of the present invention is to rationally configure a printing apparatus capable of high-quality printing by suppressing vibration of the print head even when the print head is operated at high speed.

A feature of the present invention is that ink is ejected from a print head moving in the main scanning direction onto a recording medium, and when the print head reaches the moving end, the recording medium is conveyed by a set amount in the sub-scanning direction orthogonal to the main scanning direction. Thereafter, the printing apparatus moves the print head in the reverse direction,
A vibration suppression body that suppresses vibration generated with the movement of the print head is provided to be movable along the main scanning direction with respect to the print head.

  According to this configuration, the print head moving in the main scanning direction stops when printing is performed at a high speed operation so that the print head is moved to start printing before the vibration acting on the print head is attenuated. At this timing, the kinetic energy of the print head acts in a direction that causes vibration of the print head in the vertical direction. However, since the vibration suppressing body can be freely displaced with respect to the print head by dynamic inertia, the vibration suppressing body suppresses the vibration of the print head even in a situation where the print head vibrates due to an impact. Vibration is suppressed by applying a force in the direction. Similarly, at the timing when the print head that has reached the stop state at the moving end starts high-speed movement, the kinetic energy acting on the print head acts in a direction that causes the print head to vibrate in the vertical direction. However, when the print head is in a stopped state, static inertia acts on the vibration suppressor, or the vibration suppressor has a state in which the dynamic inertia immediately before the print head stops remains. The vibration suppression body can be freely displaced, and even if the print head vibrates due to an impact, the vibration suppression body applies a force in a direction to suppress the vibration of the print head to suppress the vibration. . As a result, even if the print head is operated at high speed, a printing apparatus capable of high-quality printing by suppressing the vibration of the print head has been rationally configured.

  In the present invention, the vibration suppressing body may be accommodated in a flexible bag provided in the print head or in a space formed in the print head. According to this, it is possible to apply a force to the print head in a direction to suppress vibration while the vibration suppressing body can be freely displaced.

  In the present invention, the vibration suppressing body may be formed of a granular material or a fluid having viscosity. According to this, the granular material or the fluid having viscosity is freely displaced with respect to the print head, so that vibration is suppressed by its weight.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
〔overall structure〕
As shown in FIGS. 1 and 2, print paper P drawn from a roll-shaped print paper RP as a recording medium is supplied to a printing unit B by a transport mechanism A to print information, and the print paper P is cut. A transport system that sequentially transports the paper to the part C, the back printing part D, and the decurling part E, and discharges it to the discharge tray 2 outside the housing 1. The control unit F and the ink storage part G are provided inside the housing 1. An ink jet printing apparatus is provided.

  The transport mechanism A includes crimp-type transport rollers 4 and 5 disposed on the upstream side and the downstream side of the printing unit B in the transport direction. The transport mechanism A is also configured so that cut paper set on the manual feed tray 6 outside the housing 1 can be taken in by the pressure-feed type supply roller 7 and supplied to the printing unit B.

  As shown in FIGS. 2 to 5, the print unit B includes a print head H that reciprocates in the main scanning direction X, and a suction unit 12 that is disposed at a position facing the print paper P with respect to the conveyance path of the print paper P. Yes.

  The print head H includes a carriage 10 and an ink discharge unit 11 that is connected to the carriage 10 and discharges ink onto the print paper P to print information, and has a carriage cover 16 that covers the carriage 10. Yes. The suction unit 12 includes an electric fan (not shown) that sucks air from a large number of openings formed on the upper surface of the case-like unit and sends the air downward.

  The cutting unit C includes a transport roller 21 that transports the printed paper P in a pressure-bonded state, a disk-shaped cutter 22 that cuts the printed paper P, and an operating mechanism 23 that reciprocates the disk-shaped cutter 22 in the main scanning direction X. I have.

  The back print unit D includes a print head 24 that prints information on the back side of the print paper P. In order to correct the curl of the print paper P, the decurling unit E is configured to convey the print paper P while curving it in the direction opposite to the winding direction of the roll-shaped print paper RP. One correction roller 26 disposed at a position facing the conveyance roller 25 and a plurality of guide plates 27 are provided. Although not shown in the drawing, the decurling unit E includes an electric motor that drives the conveyance roller 25, and corrects curl when the print paper P is pressed and conveyed by the conveyance roller 25 and the correction roller 26.

  A plurality of ink cartridges (not shown) are set in the ink reservoir G, and ink sent from the ink reservoir G is supplied from an intermediate tank (not shown) to the print head H via a flexible tube. .

[Print processing form]
When printing is performed by this printing apparatus, the leading end portion of the print paper P is sent to the lower position of the print portion B by the transport mechanism A and stopped. In this state, by applying a negative pressure from the suction unit 12 to the back side of the print paper P, the print paper P is attracted to the upper surface of the suction unit 12 and maintained in a smooth state. In such a state, information is printed by ejecting ink from the ink ejection unit 11 to the print paper P while reciprocating the print head H in the main scanning direction X.

  More specifically, when the print head H reaches the moving end by moving the print head H in one of the main scanning directions X and performing printing while discharging ink from the ink discharge unit 11, printing is performed by the transport mechanism A. The paper P is transported by a predetermined amount in the sub-scanning direction Y. After this transport, the print paper H is ejected from the ink ejection unit 11 while moving the print head H to the other side of the main scanning direction X (in the reverse direction). Information is printed on P.

  The moving end refers to a position where the print head H finishes ejecting ink and stops moving the print head H. For example, the print end H prints a plurality of images on the print paper P. If the region changes, the position of the moving end changes. Note that the timing for transporting the print paper P in the sub-scanning direction Y is not limited to after the print head H stops moving, and the movement is stopped after the ink ejection from the print head H is stopped. It may be before.

  When the print paper P on which information is printed by the reciprocating operation of the print head H is conveyed to the cutting unit C, the conveyance is stopped when the cutting position of the print paper P reaches the cutting position of the disc-shaped cutter 22. . In this stopped state, the operating mechanism 23 moves the disk-shaped cutter 22 in the main scanning direction X, whereby the print paper P is cut into a print size.

  Next, the cut print paper P is printed with information specifying the order in the print head 24 of the back print unit D. Further, the print paper P is sent to the conveying roller 25, the correction roller 26, and the guide plate 27 of the decurling unit E so that the curl is corrected and then discharged onto the upper surface of the discharge tray 2.

  In this printing apparatus, the print head H is moved at a relatively high speed, and immediately after the print head H reaches the moving end and stops, before the vibration of the print head H is attenuated, the print head H is directed in the reverse direction. Moves and starts printing. For this reason, the structure for suppressing the vibration of the print head H is provided, and the structure for suppressing the vibration will be described below together with the configuration of the print unit B.

[Details of print section]
A pair of guide rods 13 having a circular cross-sectional shape are arranged on the print portion B in a posture parallel to the main scanning direction X, and a carriage 10 is supported slidably with respect to the pair of guide rods 13. The ink discharge unit 11 is connected to the lower surface side of the ink. The ink discharge unit 11 is provided with an ink discharge surface 11a in which a large number of discharge holes for discharging ink are formed at two positions spaced apart in the sub-scanning direction Y on the lower surface.

  One side surface of the carriage 10 in the sub-scanning direction Y is provided with a pair of slide guides 14 formed with circular holes so as to be fitted around one guide rod 13, and the other guide rod is provided on the other side surface. 13 is provided with a slide block 15 in which a concave portion that engages with 13 is formed. The carriage 10 is provided with a carriage cover 16 at the top.

  A timing belt type driving belt 19 wound around the driving pulley 17 and the idle pulley 18 is disposed along the main scanning direction X on the side portion of the carriage 10. The driving belt 19 and the carriage 10 are connected to each other, and a rotational driving force is transmitted from the driving motor M to the driving pulley 17. The drive pulley 17 includes a rotary encoder 20 that determines the position of the print head H in the main scanning direction X from the rotation amount. In this printing apparatus, a linear encoder may be used along the print head H in order to determine the position of the print head H in the main scanning direction X.

  In this way, the driving pulley 17, the idle pulley 18, the driving belt 19, and the driving motor M constitute moving means for the print head H.

  The control unit F acquires information such as images and characters to be printed, controls the transport mechanism A, controls the drive motor M based on the feedback signal from the encoder 20, and synchronizes with the drive of the drive motor M. By controlling the drive mechanism built in the ink discharge unit 11, ink is discharged from the discharge holes of the ink discharge surface 11a to print information. The control unit F controls the operating mechanism 23 of the cutting unit C, controls the print head 24 of the back printing unit D, and controls the decurling unit E.

(Vibration suppressor)
As shown in FIG. 3 to FIG. 6, in this printing apparatus, a plurality of granular suppressors Q as an example of the vibration suppressing body Q with respect to the bag body 30 made of a flexible material made of cloth or a resin sheet on the upper surface of the carriage cover 16. By encapsulating the metal piece 31, vibration of the print head H is suppressed.

  The vibration suppression body Q has a certain amount of weight in order to suppress vibration by causing the print head H to act on the print head H with the force caused by the dynamic inertia and static inertia accompanying the movement of the print head H and the weight of the vibration suppression body Q itself. Need. For this reason, the metal piece 31 is used as the vibration suppressing body Q.

  The bag 30 has a sufficient volume so that the metal piece 31 can be freely displaced, and is supported by the print head H by fixing its end in the main scanning direction X to the carriage cover 16 with screws 32. Has been. Further, the metal piece 31 is sealed with a sufficient space so that the metal piece 31 can move inside the bag body 30.

  The metal piece 31 desirably has a relatively heavy weight for suppressing vibrations, and moves in the main scanning direction X and the sub-scanning direction Y when the print head H moves rather than smoothly rolling like a ball. Since a material that is rubbed by applying a slight frictional force to the print head H is effective in suppressing vibration, use of a polyhedral structure is conceivable.

  In the present invention, the print head H may include a member other than the carriage 10, the ink discharge unit 11, and the carriage cover 16. And the bag body 30 may be provided with respect to any side surface or bottom surface of the members constituting the print head H, and the vibration suppressing body Q such as the metal piece 31 may be enclosed in the bag body 30.

  In particular, a housing space may be formed inside a member constituting the print head H, and the vibration suppressing body Q such as the metal piece 31 as the vibration suppressing body Q may be enclosed in the housing space. In this case, in the print head H, the volume of the accommodation space is larger than the total volume of the metal pieces 31, and a space sufficient for the metal pieces 31 to move in the main scanning direction X is formed.

[Another Embodiment of Vibration Suppressor]
In the present invention, the fluid 33 may be used as the vibration suppressing body Q. That is, oils, emulsions, or slurries with relatively high viscosity are assumed. Specifically, as shown in FIG. 7, a concave portion 10a is formed on the upper surface of the carriage 10, and the carriage cover 16 is fixed with screws 34 so as to cover the concave portion 10a, whereby the fluid 33 is enclosed in the print head H. ing. In this case, a space having a volume larger than the volume of the vibration suppression fluid enclosed so that the fluid 33 can move in the main scanning direction X is formed.

  Further, as a space in the print head H, a cylindrical hole is formed in an axial center parallel to the main scanning direction X with respect to the members constituting the print head H, and the vibration suppressing body Q is provided in the hole. After sealing, a structure in which the end of the hole is closed with plugs may be employed. Further, the print head H may be provided with a cylindrical structure having a space inside.

  Also in this other embodiment, for example, a structure in which a bag made of a flexible material made of cloth or a resin sheet is fixed to the carriage 10 or the carriage cover 16 and the fluid 33 is enclosed in the bag may be used. . In particular, in the present invention, a bag body may be provided on any side surface or bottom surface of a member constituting the print head H, and the fluid 33 may be enclosed in the bag body.

(Vibration suppression)
As described above, the carriage 10 is slidably supported by the slide guide 14 fitted around one of the pair of guide rods 13 and the slide block 15 engaged with the other guide rod 13. Due to such a support structure, the carriage 10 cannot move up and down on the side where the slide guide 14 is provided, but can move up and down slightly on the side where the slide block 15 is disposed.

  As described above, since the vertical movement of the end portion of the carriage 10 in the sub-scanning direction Y is allowed, when the carriage 10 that moves at high speed stops and starts moving at high speed in the opposite direction, the kinetic energy is reduced. As a result of acting on the carriage 10, vibration appears in a direction with low rigidity, and vibration in a form in which the end portion of the carriage 10 in the sub-scanning direction Y is displaced up and down is generated. In order to suppress such vibration, the vibration suppressing body Q functions.

  That is, even when the kinetic energy between the carriage 10 and the print head H acts in the direction that causes the print head H to vibrate in the vertical direction at the timing when the print head H moving in the main scanning direction X stops, the vibration suppressing body. Q can be displaced in the main scanning direction X by dynamic inertia, and the print head H is pressed down by the weight of the vibration suppressing body Q. Specifically, every time the print head H reaches the moving end, the metal piece 31 as the vibration suppressing body Q is mainly between the state shown in FIG. 6A and the state shown in FIG. As a result of moving in one direction of the scanning direction X, the print head H is pressed down.

  In the case of using the fluid 33 as the vibration suppressor Q, the fluid 33 as the vibration suppressor Q is in the main scanning direction from the state as shown in FIG. 7A in the form shown in FIG. 7B. As a result of moving in one direction of X, the print head H is pressed down.

  For this reason, the kinetic energy of the vibration suppressor Q does not act in the direction that causes vibration. In addition, since the vibration suppressing body Q is in a state of being displaced in the main scanning direction X, the vibration of the print head H can be suppressed by the weight of the vibration suppressing body Q.

  Similarly, even when the kinetic energy acts in a direction that causes the print head H to vibrate in the vertical direction at the timing when the stopped print head H starts moving at high speed, the vibration suppression body Q has a static inertia. Or the vibration suppression body Q operates in a state in which the dynamic inertia immediately before the print head H stops (dynamic inertia in the main scanning direction X) remains. The body Q is displaced with a delay in the main scanning direction X, and the vibration of the print head H can be suppressed by pressing the print head H by the weight of the vibration suppression body Q.

  In this way, the print head H is operated at high speed to print information by ejecting ink. When the print head H reaches the moving end, the moving direction is changed before the vibration of the print head H is attenuated. Even if the print head H is reversed and the high-speed movement of the print head H is resumed, the vibration at the time of reversal of the print head H is suppressed and high-quality printing is realized. The present invention can also be applied to a printing apparatus in which a print mode is set so that ink is ejected only when the print head H moves to one side (for example, when moving from left to right).

  In particular, in the present invention, the carriage 10, the ink discharge unit 11, and the carriage cover 16 have been described as different members. However, they are configured to be directly supported by the guide rod 13 as a print head H that is integrally formed. It may be a thing.

The perspective view which shows the main structures of a printing apparatus Vertical side view showing the main configuration of the printing device Plan view showing the operating system of the print head Perspective view of carriage printhead Side view of carriage printhead Sectional drawing which shows the state of a vibration suppression body Sectional drawing which shows the state of another embodiment of a vibration suppression body.

Explanation of symbols

30 Bag 33 Fluid H Print head P Recording medium (print paper)
Q Vibration suppression body X Main scanning direction

Claims (3)

Ink is ejected from the print head moving in the main scanning direction onto the recording medium, and when the print head reaches the moving end, the recording medium is transported by a set amount in the sub-scanning direction orthogonal to the main scanning direction. A printing device that moves the print head in the reverse direction,
A printing apparatus, comprising: a vibration suppressing body that suppresses vibration generated along with the movement of the print head so as to be movable along the main scanning direction with respect to the print head.   The printing apparatus according to claim 1, wherein the vibration suppressing body is accommodated in a flexible bag provided in the print head or a space formed in the print head.   The printing apparatus according to claim 2, wherein the vibration suppression body is configured by a granular material or a fluid having viscosity.

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