JP5728876B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus.

  2. Description of the Related Art Conventionally, for example, as described in Patent Document 1, a printing system in which a buffer unit is provided between a plurality of processing units is known. According to this printing system, when printing on a web-like print medium, the print medium can be stored in the buffer unit even when the processing times of the plurality of processing units are different from each other. Printing is possible.

JP 2008-1103 A

By the way, as a some process part, not only a printing process but the surface process for improving the uniformity of printing, for example is also considered. In order to uniformly treat the printing surface of the printing medium and ensure high printing quality, it is preferable to always carry the printing medium at a constant conveyance speed.
In the printing unit, when a high-definition image such as a photograph is printed, the resolution becomes high, and the printing time becomes long. On the other hand, when printing text that is not particular about image quality, a lower resolution may be used, so that the printing time can be shortened.
Such a surface treatment unit and a printing unit can be applied to the printing system described in Patent Document 1. In this case, it is necessary to set the storage amount of the print medium in the buffer unit, assuming the longest printing time in the printing unit. For this reason, since the buffer portion tends to be large, the printing apparatus tends to be large. In addition, when the printing time in the printing unit is short, extra roll-shaped medium is stored in the buffer unit, which is wasteful and inefficient.
That is, the conventional printing apparatus has a problem that it is difficult to reduce the size.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 A printing apparatus according to the present application includes a surface treatment unit that applies surface treatment to the print medium by applying energy to the print medium conveyed in the conveyance direction, and the conveyance more than the surface treatment unit. Provided on the downstream side of the direction and provided between the surface treatment unit and the printing unit, a printing unit that performs a printing process on the print medium intermittently conveyed in a series from the surface treatment unit, and the surface A buffer unit that stores the print medium by sagging the print medium between the processing unit and the printing unit; and a control unit that controls the surface treatment unit, the control unit including the printing unit depending on the speed of the printing process in the transport speed of the print medium in the surface treatment section, wherein changing the output intensity of energy in the surface treatment section, in the intermittent conveyance, the print medium Are alternately set in a conveyance period that is a period during which the printing medium is conveyed in a conveyance direction and a stop period that is a period during which the conveyance of the print medium is stopped, and the control unit is configured to perform the printing that is conveyed in the conveyance period. The transport speed of the print medium in the surface treatment unit is calculated by dividing the transport amount of the medium by the time from the transport period to the next transport period, and the unit of the print medium is calculated to the calculated transport speed. The output intensity of the energy is calculated by multiplying the amount of energy required per amount .

In the printing apparatus of this application example, even if there is a difference between the printing medium conveyance speed in the surface processing unit and the printing medium conveyance speed in the printing unit, the buffer unit performs surface treatment on a series of printing media. And printing processing can be performed.
In this printing apparatus, the control unit changes the conveyance speed of the print medium in the surface processing unit and the output intensity of energy in the surface processing unit according to the speed of the printing process in the printing unit. By changing the printing medium conveyance speed in the surface processing section according to the printing processing speed in the printing section, the amount of the printing medium stored in the buffer section can be easily maintained regardless of the printing processing speed. Can do. As a result, it is possible to easily avoid an increase in the size of the buffer unit, and thus it is possible to easily reduce the size of the printing apparatus.
Note that if the conveyance speed of the print medium in the surface treatment unit is changed, there may be a difference in the effect of the surface treatment between when the conveyance speed is high and when the conveyance speed is low. On the other hand, in this printing apparatus, the printing medium conveyance speed in the surface treatment unit and the energy output intensity in the surface treatment unit are changed according to the speed of the printing process in the printing unit. For this reason, the effect of the surface treatment can be easily maintained regardless of the speed of the printing process.

Further , according to the present application, the control unit divides the print medium conveyance amount in the intermittent conveyance period by the time from the conveyance period to the next conveyance period, so that the print medium conveyance speed in the surface treatment unit is obtained. Is calculated. This makes it easy to keep the amount of print medium stored in the buffer unit constant regardless of the speed of the printing process.
In this printing apparatus, the control unit calculates the output intensity of energy by multiplying the calculated conveyance speed by the amount of energy required per unit amount of the print medium. Thereby, the effect of the surface treatment can be easily maintained regardless of the speed of the printing process.

Application Example 2 In the printing apparatus, it is preferable that the surface treatment unit performs the surface treatment on the print medium by irradiating the print medium with corona discharge as the energy.

  According to this application example, since the surface treatment unit irradiates the print medium with corona discharge as energy, the print medium can be subjected to the surface treatment.

Application Example 3 In the above-described printing apparatus, the surface treatment unit irradiates the print medium as the energy with plasma excited in an environment containing at least one of nitrogen and oxygen. It is preferable to perform a surface treatment.

  According to this application example, since the surface treatment unit irradiates the print medium with energy that is excited in an environment containing at least one of nitrogen and oxygen, the print medium can be subjected to a surface treatment.

Application Example 4 In the printing apparatus, it is preferable that the surface treatment unit performs the surface treatment on the print medium by irradiating the print medium with ultraviolet light as the energy.

  According to this application example, since the surface treatment unit irradiates the print medium with ultraviolet light as energy, the print medium can be subjected to the surface treatment.

Application Example 5 In the above printing apparatus, it is preferable that the printing unit includes an inkjet head that ejects ink droplets onto the printing medium.

  According to this application example, since the printing unit includes the ink jet head that ejects ink droplets onto the print medium, printing can be performed on the print medium with ink.

1 is a front view illustrating a printing apparatus according to an embodiment. The front view which shows the structure of the outline of a corona treatment apparatus. The front view which shows the structure of the outline of a buffer part. 1 is a front view showing a schematic configuration of an ink jet printer.

  Hereinafter, an embodiment in which a printing unit of a printing apparatus according to the present invention is embodied as a lateral ink jet printer will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is made different from the actual scale so that each layer and each member can be recognized.

FIG. 1 is a front view showing a printing apparatus according to the present embodiment.
The printing apparatus 1 according to the present embodiment includes a feeding machine 4 for feeding the feeding roll 3 wound around the printing medium 2 in a roll shape in the transport direction X, and a surface treatment by applying energy to the printing medium 2. A corona treatment device 5 as a surface treatment unit for performing printing, a buffer unit 6 for temporarily storing the print medium 2, an inkjet printer 7 as a printing unit for printing on the print medium 2, and the print medium 2. And a winder 9 for winding as the take-up roll 8. The feeding machine 4, the corona treatment device 5, the buffer unit 6, the ink jet printer 7, and the winder 9 are arranged in this order from the upstream side in the transport direction X.
In the present embodiment, the print medium 2 is composed of a polypropylene sheet.

The corona treatment device 5 performs a surface treatment on the print medium 2 while keeping the conveyance speed of the print medium 2 substantially constant.
The ink jet printer 7 performs printing on the print medium 2 while intermittently transporting the print medium 2. In the intermittent conveyance, a conveyance period that is a period for conveying the print medium 2 in the conveyance direction X and a stop period that is a period for stopping the conveyance of the print medium 2 are provided. In the inkjet printer 7, printing is performed on the print medium 2 during the stop period.
As described above, the conveyance speed of the print medium 2 is different between the corona treatment device 5 and the ink jet printer 7. This difference in transport speed is alleviated by the buffer unit 6 provided between the corona treatment device 5 and the ink jet printer 7. For this reason, in the printing apparatus 1, the surface treatment in the corona treatment apparatus 5 and the printing in the inkjet printer 7 can be continuously performed in a roll-to-roll form.

Here, the corona treatment device 5 has a control unit 11.
The ink jet printer 7 has a print control unit 12.
In the present embodiment, the control unit 11 acquires print information in the inkjet printer 7 from the print control unit 12. The control unit 11 controls the conveyance speed of the printing medium 2 in the corona treatment device 5 and the amount of energy applied to the printing medium 2 based on the acquired printing information.
The print information in the ink jet printer 7 includes a stop period in intermittent conveyance, a cycle time from the start of the conveyance period to the start of the next conveyance period, information on time such as time required for printing in one stop period, and the like. Can be mentioned. The print information is not limited to these, and any information can be adopted as long as the information is associated with the cycle time from the start of the transport period to the start of the next transport period.

FIG. 2 is a front view showing a schematic configuration of the corona treatment device 5.
As shown in FIG. 2, the corona treatment device 5 includes a transport device 14, a corona discharge electrode 15, a ground electrode 16, an oscillator 17, and an electrode cover 18 in addition to the control unit 11. .
The transport device 14 includes a transport roller 21, a nip roller 22, and a drive motor 23. The drive motor 23 generates power for rotationally driving the transport roller 21. The transport device 14 transports the print medium 2 in the transport direction X when the transport roller 21 is driven by the drive motor 23 while the print medium 2 is sandwiched between the transport roller 21 and the nip roller 22.

The corona discharge electrode 15 and the ground electrode 16 are provided upstream of the transport device 14 in the transport direction X, respectively. The corona discharge electrode 15 and the ground electrode 16 are provided at positions facing each other with the print medium 2 interposed therebetween.
The corona discharge electrode 15 is a ceramic electrode in which a cylindrical aluminum rod is coated with ceramic. A stainless steel cylindrical ground electrode 16 is disposed below the corona discharge electrode 15 with a gap of 0.5 to 2 mm. Then, the print medium 2 passes between the corona discharge electrode 15 and the ground electrode 16 to perform surface treatment. The shape of the ground electrode 16 may be a flat plate as long as it is a material that conducts electricity. However, in order to increase the adhesion between the ground electrode 16 and the print medium 2 and increase the surface treatment efficiency, the shape of the ground electrode 16 may be Is preferred.

The oscillator 17 supplies power to the corona discharge electrode 15. When the corona discharge electrode 15 is supplied with power from the oscillator 17, it generates a corona discharge between the corona discharge electrode 15 and the ground electrode 16.
The electrode cover 18 is provided outside the corona discharge electrode 15 and covers the outer periphery of the corona discharge electrode 15. The electrode cover 18 is connected to an exhaust system (not shown), collects ozone generated by corona discharge, and prevents a person from directly touching the electrode during discharge.
The control unit 11 is electrically connected to each of the oscillator 17 and the drive motor 23.
The control unit 11 controls the amount of power supplied from the oscillator 17 to the corona discharge electrode 15 based on the printing information from the ink jet printer 7. That is, the amount of corona discharge energy in the corona treatment device 5 is controlled based on the print information from the ink jet printer 7.
Further, the control unit 11 controls the rotation speed of the drive motor 23 based on the print information from the inkjet printer 7. That is, the conveyance speed of the printing medium 2 in the corona treatment device 5 is controlled based on the printing information from the inkjet printer 7.

FIG. 3 is a front view showing a schematic configuration of the buffer unit 6.
As shown in FIG. 3, the buffer unit 6 has three idle rollers 25 and two dancer rollers 26.
The three idle rollers 25 are arranged along the transport direction X. One dancer roller 26 is provided between two idle rollers 25 adjacent to each other in the transport direction X.
Each of the two dancer rollers 26 is configured to be movable up and down in the Z direction intersecting with the transport direction X.
In the following description, when each of the three idle rollers 25 is identified, the three idle rollers 25 are represented as an idle roller 25a, an idle roller 25b, and an idle roller 25c, respectively. Moreover, when identifying each of the two dancer rollers 26, the two dancer rollers 26 are denoted as a dancer roller 26a and a dancer roller 26b, respectively.

In the buffer unit 6, in the transport direction X, the idle roller 25a, the dancer roller 26a, the idle roller 25b, the dancer roller 26b, and the idle roller 25c are arranged in this order. The print medium 2 is conveyed to the inkjet printer 7 via the idle roller 25a, the dancer roller 26a, the idle roller 25b, the dancer roller 26b, and the idle roller 25c in this order.
As described above, since the two dancer rollers 26 can be moved up and down, when the printing medium 2 is supplied from the corona treatment device 5 side to the buffer unit 6, each dancer roller 26 moves downward due to its own weight. 6, the print medium 2 is stored. When the print medium 2 is supplied to the inkjet printer 7, each dancer roller 26 moves upward due to the tension of the print medium 2, and the stored amount is sent out.

FIG. 4 is a front view illustrating a schematic configuration of the inkjet printer 7.
In addition to the print control unit 12, the inkjet printer 7 includes a transport device 29, a platen 31, a pair of guide rails 32, a carriage 33, and an inkjet head 34.
The transport device 29 includes a transport roller 36, a nip roller 37, and a drive motor 38. The drive motor 38 generates power for driving the transport roller 36 to rotate. The transport device 29 transports the print medium 2 in the transport direction X by driving the transport roller 36 by the drive motor 38 in a state where the print medium 2 is sandwiched between the transport roller 36 and the nip roller 37.

The platen 31 is provided below the print medium 2 in the Z direction on the upstream side of the transport device 29 in the transport direction X. The platen 31 is provided at a position facing the print medium 2 on the lower side of the print medium 2 in the Z direction. The platen 31 supports the print medium 2 from the lower side of the print medium 2 in the Z direction.
A plurality of holes (not shown) are formed in the platen 31 on the side facing the print medium 2. The platen 31 has a suction fan 39 inside. In the platen 31, the negative pressure is generated by the suction fan 39, so that the print medium 2 can be adsorbed to the platen 31 during the intermittent conveyance stop period.
On the other hand, when the print medium 2 is conveyed, the suction force is weakened by lowering the rotational speed of the suction fan 39. Thereby, the printing medium 2 can be smoothly conveyed in the conveyance period of intermittent conveyance.
The area from the upstream end to the downstream end of the platen 31 is set as the print area L. The print area L is an area in which printing can be performed on the print medium 2 by the inkjet printer 7.

The pair of guide rails 32 are provided at positions facing the platen 31 with the print medium 2 interposed therebetween. The pair of guide rails 32 extend along the transport direction X, and are arranged in a state where a gap is left between them in a direction intersecting the X direction in plan view. The pair of guide rails 32 extends over the printing area L.
The carriage 33 is supported by a pair of guide rails 32 and is configured to reciprocate between the upstream side and the downstream side of the printing region L along the transport direction X. That is, the carriage 33 can reciprocate between the upstream side and the downstream side of the printing region L by being guided by the pair of guide rails 32.
The inkjet head 34 is held by the carriage 33 in a state of facing the platen 31 with the print medium 2 interposed therebetween. A gap is maintained between the inkjet head 34 and the print medium 2. Therefore, the inkjet head 34 can reciprocate between the upstream side and the downstream side of the printing region L along the transport direction X as the carriage 33 moves.
The inkjet head 34 is provided with a plurality of nozzles (not shown) that eject ink as ink droplets on the surface of the print medium 2 side.

The print control unit 12 is electrically connected to the drive motor 38, the suction fan 39, the carriage 33, and the inkjet head 34.
The print control unit 12 controls driving of the drive motor 38. In the inkjet printer 7, the print control unit 12 intermittently drives the drive motor 38 to intermittently convey the print medium 2.
Further, the print control unit 12 controls the driving of the suction fan 39. Thereby, the printing medium 2 can be adsorbed on the platen 31 or can be weakened.
Further, the print control unit 12 controls the movement of the carriage 33. Thereby, the carriage 33 can be moved in the printing region L.
Further, the print control unit 12 controls driving of the inkjet head 34. Thereby, ink can be ejected from the inkjet head 34 as ink droplets.
In the ink jet printer 7, ink droplets are ejected from the ink jet head 34 while the carriage 33 is moved in the print region L along the transport direction X in a state where the print medium 2 is adsorbed to the platen 31 in the intermittent transport stop period. As a result, the printing process on the print medium 2 is performed.

Here, the surface treatment for the print medium 2 will be described.
In the corona treatment device 5, the wettability of the print medium 2 with respect to the ink can be improved by corona discharge. Hereinafter, improving the wettability of the printing medium 2 with respect to the ink is referred to as surface modification of the printing medium 2.
The degree of wettability in the print medium 2 can be known by measuring the surface tension of the print medium 2. For example, when a reagent having a surface tension of a specific value S (mN / m) is thinly spread on the print medium 2, the surface tension of the print medium 2 is smaller than S (mN / m) when the reagents gather together. Conversely, if it remains thinly spread, it can be determined that it is larger than S (mN / m). If the surface tension of the ink ejected from the inkjet head 34 is lower than the surface tension of the reagent, the ink wets and spreads cleanly on the print medium 2.

  In this embodiment, as a result of the preliminary experiment, a surface tension of S (mN / m) can be obtained when the output of the oscillator 17 is 200 W and the conveyance speed of the printing medium 2 in the corona treatment device 5 is 2.5 m / min. I understood. For this reason, in order to obtain the surface tension of S (mN / m) in the print medium 2, an energy amount of 80 W · min / m per unit length in the transport direction X of the print medium 2 is required.

A method for calculating the conveyance speed of the printing medium 2 and the energy amount of corona discharge in the corona treatment device 5 will be described. The calculation of the conveyance speed of the printing medium 2 and the energy amount of the corona discharge is performed by a calculation unit (not shown) included in the control unit 11.
In the ink jet printer 7, the carriage 33 takes 10 seconds to print the printing area L twice, that is, once in 4 passes, and the carriage 33 takes 40 seconds to print the printing area L 8 times, that is, once in 16 passes. And a high-definition mode for performing printing.
In the present embodiment, the control unit 11 of the corona processing device 5 acquires information indicating whether the mode is the normal mode or the high-definition mode as print information from the print control unit 12.

At this time, when the acquired print information indicates the normal mode, the control unit 11 first calculates the conveyance speed v of the print medium 2 in the corona treatment device 5 based on the following equation (1). .
v [m / min] = L [m] / (10/60 [min]) = 6 × L (1)
And the control part 11 calculates the output p of the oscillator 17 which will be 80 W * min / m based on Formula (2).
p [W] = 80 [W · min / m] × v [m / min] = 480 × L (2)
The controller 11 controls the oscillator 17 and the drive motor 23 based on these v and p.

On the other hand, when the acquired print information indicates the high-definition mode, the control unit 11 first calculates the conveyance speed v of the print medium 2 in the corona treatment device 5 based on the following equation (3). To do.
v [m / min] = L [m] / (40/60 [min]) = 1.5 × L (3)
And the control part 11 calculates the output p of the oscillator 17 which will be 80 W * min / m based on Formula (4).
p [W] = 80 [W · min / m] × v [m / min] = 120 × L (4)
The controller 11 controls the oscillator 17 and the drive motor 23 based on these v and p.

As described above, even when the printing mode is different and the printing time in the ink jet printer 7 becomes longer or shorter, the buffer unit 6 may ensure the maximum storage amount that can be printed by the ink jet printer 7. Therefore, the apparatus can be downsized and the waste of the print medium 2 can be reduced.
In the present embodiment, the corona treatment device 5 corresponds to the surface treatment unit, and the ink jet printer 7 corresponds to the printing unit.

In the present embodiment, an ink jet printer 7 is employed as the printing unit. The inkjet printer 7 has an inkjet head 34 that ejects ink as ink droplets. Thereby, it is possible to print on the print medium 2 with ink.
Since such an ink jet printer 7 does not require plate making, printing can be performed efficiently. In addition, since printing can be performed on the print medium 2 in a non-contact manner, printing can be performed even if the surface of the print medium 2 has an uneven shape.

The conveyance speed v of the printing medium 2 in the corona treatment device 5 is calculated by dividing the printing region L in the inkjet printer 7 by the printing time required for one printing. Further, the amount of energy per unit length required for the surface modification obtained in the preliminary experiment is set as a proportionality constant, and the output of the oscillator 17 is obtained by multiplying this by the conveyance speed v.
That is, if the conveyance speed v of the print medium 2 is slow, the output intensity of energy applied to the print medium 2 is low, and if the conveyance speed v of the print medium 2 is high, the output intensity of energy applied to the print medium 2 is controlled high. Thus, the energy amount per unit length given to the print medium 2 can be made constant regardless of the conveyance speed. Therefore, regardless of the length of the printing time in the inkjet printer 7, a certain energy can be applied to the printing medium 2 and the surface treatment can be performed, so that a stable printing image quality can be ensured.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below.

(Modification 1)
In the above embodiment, the corona treatment is used as the surface treatment to be applied to the printing medium 2, but the present invention is not limited to this. For example, atmospheric pressure plasma using a gas containing at least one of nitrogen and oxygen Surface treatment by may be used. In the surface treatment using atmospheric pressure plasma using a gas containing at least one of nitrogen and oxygen, the surface treatment can be applied to the printing medium 2 made of a material that is damaged by corona discharge.

(Modification 2)
Similarly, a surface treatment by ultraviolet light (UV) irradiation may be used as the surface treatment applied to the print medium 2. In the surface treatment by UV irradiation, for example, the surface treatment can be performed on the print medium 2 formed of a conductive material such as metal.

  DESCRIPTION OF SYMBOLS 1 ... Printing apparatus, 2 ... Print medium, 5 ... Corona treatment apparatus, 6 ... Buffer part, 7 ... Inkjet printer, 11 ... Control part, 12 ... Print control part, 14 ... Conveyance apparatus, 15 ... Corona discharge electrode, 16 ... Ground electrode, 17 ... Oscillator, 25 ... Idle roller, 25a, 25b, 25c ... Idle roller, 26 ... Dancer roller, 26a, 26b ... Dancer roller, 29 ... Conveyor device, 31 ... Platen, 32 ... Guide rail, 33 ... Carriage 34: Inkjet head.

Claims (5)

A surface treatment unit for applying a surface treatment to the print medium by applying energy to the print medium conveyed in the conveyance direction;
A printing unit that is provided downstream of the surface treatment unit in the conveyance direction and that performs a printing process on the print medium that is intermittently conveyed in a series from the surface treatment unit;
A buffer unit that is provided between the surface treatment unit and the printing unit, and stores the print medium by sagging the print medium between the surface treatment unit and the printing unit;
A control unit for controlling the surface treatment unit,
The control unit changes a conveyance speed of the print medium in the surface treatment unit and an output intensity of the energy in the surface treatment unit according to a speed of the printing process in the printing unit ,
In the intermittent conveyance, a conveyance period that is a period for conveying the print medium in the conveyance direction and a stop period that is a period for stopping conveyance of the print medium are alternately set,
The control unit calculates the transport speed of the print medium in the surface treatment unit by dividing the transport amount of the print medium transported during the transport period by the time from the transport period to the next transport period. And the output intensity of the energy is calculated by multiplying the calculated transport speed by the amount of energy required per unit amount of the print medium . The printing apparatus according to claim 1 ,
The printing apparatus, wherein the surface treatment unit performs the surface treatment on the print medium by irradiating the print medium with corona discharge as the energy. The printing apparatus according to claim 1 ,
The surface treatment unit performs the surface treatment on the print medium by irradiating the print medium as the energy with plasma excited in an environment containing at least one of nitrogen and oxygen. . The printing apparatus according to claim 1 ,
The printing apparatus, wherein the surface treatment unit performs the surface treatment on the print medium by irradiating the print medium with ultraviolet light as the energy. The printing apparatus according to any one of claims 1 to 4 ,
The printing apparatus, wherein the printing unit includes an inkjet head that ejects ink droplets onto the printing medium.

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