JP7461190B2 - inkjet printing equipment - Google Patents

Description

The present invention relates to an inkjet printing device.

An inkjet printing device includes a transport mechanism that transports a base material, and an image recording section that records an image on the transported base material according to image data.

The transport mechanism is equipped with a drive roller that actively rotates. A pressure roller that presses the substrate toward the drive roller is attached to the drive roller (for example, Patent Document 1). The drive roller rotates with the pressure roller pressing against the substrate, allowing the substrate to be transported stably.

JP2009-286636A

Inkjet printing devices perform printing based on various image data. However, the conveyance device is not designed to convey the base material in response to changes in image data. For this reason, the base material may not be transported stably.

Therefore, the present invention aims to provide an inkjet printing device that can transport substrates stably.

In order to achieve the above object, the present invention has the following configuration.

That is, one embodiment of the present invention includes a base material conveyance section including a drive roller and a pressing roller that presses a base material toward the surface of the drive roller, and a base material conveyed by the base material conveyance section. In an inkjet printing apparatus, the press roller is moved in a direction parallel to the rotation axis of the drive roller. An inkjet printing device is provided that includes a pressure roller moving member and a pressure roller control section that controls the pressure roller moving member with reference to the image data.

In one embodiment, a standard position of the pressure roller is preset for each width size of the substrate supplied to the drive roller, and the pressure roller control unit determines whether or not to move the pressure roller from the standard position by referring to the image data.

In one embodiment, the pressure roller control unit refers to the image data and determines not to move the pressure roller from the standard position when an amount of movement of the pressure roller from the standard position is equal to or greater than a threshold value .
In one embodiment, when overlap between the pressure roller and any of a plurality of image components contained in the image cannot be avoided, the pressure roller control unit controls the pressure roller moving member so that the pressure roller moves to a position where it overlaps with the image component having the lowest ink density among the plurality of image components.

In one embodiment, the inkjet printing apparatus further comprises a pressure varying unit that varies the pressure of the pressure roller against the substrate in accordance with the thickness of the substrate being used.

According to this invention, the pressure roller control unit refers to image data and controls the pressure roller moving member to move the pressure roller in a direction parallel to the rotation axis of the drive roller. This moves the pressure roller to a position where ink is less likely to adhere, thereby suppressing ink transfer from the substrate to the pressure roller. As a result, the drive roller and the pressure roller work together to stably transport the substrate.

1 is a schematic configuration diagram of an inkjet printing apparatus 1 according to an embodiment. 5 is a top view of the pressure roller drive section 50. FIG. It is a control block diagram. 5A and 5B are schematic diagrams illustrating control for changing the positions of pressure rollers 15a and 15b in accordance with the paper width of printing paper 9. 5A and 5B are schematic diagrams illustrating control for changing the positions of pressure rollers 15a and 15b in accordance with an image to be printed on printing paper 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, the direction in which the print paper 9 is transported will be referred to as the "transport direction", and the horizontal direction perpendicular to the transport direction will be referred to as the "paper width direction".
1. Configuration of the Printing Device
Fig. 1 is a schematic diagram of a printing device 1 according to one embodiment of the present invention. The printing device 1 is an inkjet printing device that records an image on the surface of a long strip-shaped substrate, a printing paper 9, by an inkjet method while transporting the printing paper 9 in the longitudinal direction. As shown in Fig. 1, the printing device 1 includes a transport mechanism 10, an image recording unit 20, a drying unit 30, and a control unit 40.

The transport mechanism 10 is a mechanism for transporting the print paper 9 along a predetermined transport path. In this embodiment, the transport mechanism 10 has an unwinding section 11, a winding section 12, a plurality of drive rollers 13, and a driven roller 14. A motor (not shown) that serves as a power source is connected to the unwinding section 11 and the winding section 12.

The unwinding section 11 is a member that holds a roll of printing paper 9 (printing paper roll Ro). The unwinding section 11 can hold one printing paper roll Ro.

The drive roller 13 is a drive roller 13 that rotates spontaneously by the power of a motor (not shown). The drive roller 13 cooperates with the pressure roller 15 to nip the printing paper 9 and transport the printing paper 9. On the other hand, the driven roller 14 is not connected to the motor and rotates in accordance with the movement of the printing paper 9.

The plurality of drive rollers 13 and driven rollers 14 constitute a conveyance path for the printing paper 9. Each driving roller 13 and driven roller 14 guides the printing paper 9 to the downstream side of the conveyance path by rotating around a horizontal axis. Further, by the printing paper 9 coming into contact with each drive roller 13 and the driven roller 14, tension is applied to the printing paper 9.

When the control unit 40 drives the motors connected to the unwinding unit 11, the winding unit 12, and the drive roller 13, the unwinding unit 11, the winding unit 12, and the drive roller 13 rotate, respectively. As a result, the printing paper 9 is unwound from the unwinding section 11 and conveyed to the winding section 12 via the plurality of conveyance rollers 13 and 14.

The image recording unit 20 ejects ink droplets d onto the printing paper 9 transported by the transport mechanism 10 to record an image.

The image recording section 20 of this embodiment has four recording heads 21. The four recording heads 21 are arranged above the conveyance path of the printing paper 9 at intervals in the conveyance direction. Each recording head 21 has a plurality of ejection ports arranged parallel to the paper width direction of the printing paper 9. The four recording heads 21 eject each color of cyan (C), magenta (M), yellow (Y), and black (K), which are the color components of a color image, from a plurality of ejection ports toward the top surface of the printing paper 9. Each ink droplet is ejected. As a result, a color image is recorded on the upper surface of the printing paper 9. Note that the number of recording heads 21 is not limited to four, and may be less than four or more than four. If the number exceeds 4, a recording head 21 may be provided that ejects ink droplets of so-called special color ink such as orange or blue, magnetic ink, or invisible ink.

The image recording unit 20 of this embodiment is a so-called one-pass type recording unit. That is, the four recording heads 21 are fixed and do not move back and forth in the paper width direction. The image recording unit 20 records an image on the upper surface of the printing paper 9 by ejecting ink droplets from each recording head 21 while the printing paper 9 passes under each recording head 21 only once.

The drying unit 30 heats and dries the printing paper 9 onto which ink has been applied by the image recording unit 20.

The control section 40 controls the operation of each section within the printing apparatus 1 . As conceptually shown in FIG. 1, the control unit 40 is constituted by a computer having an arithmetic processing unit 401 such as a CPU, a memory 402 such as a RAM, and a storage unit 403 such as a hard disk drive.

FIG. 2 is a top view of the drive roller 13, the pressure roller 15 attached to the drive roller 13, and the pressure roller drive section 50 that drives the pressure roller 15. The drive roller 13 is a roller that is rotatable around a rotating shaft 131, and is rotated by a motor 133 via a shaft 132.

The drive roller 13 has a roller surface 135 around which the printing paper 9 entering in the direction of arrow 134 (conveyance direction) can be wound. Coordinates in the paper width direction X are set for the roller surface 135. That is, the center position in the paper width direction It is set.

Two pressure rollers 15a and 15b are attached to the drive roller 13. The pressure rollers 15a and 15b have a case C and a rotating body R rotatably supported inside the case C. The surface of the rotating body R presses the printing paper 9 against the roller surface 135 of the drive roller 13, allowing the drive roller 13 to transport the printing paper 9 stably.

The pressure rollers 15a and 15b are individually movable by a pressure roller drive unit 50 in a direction parallel to the rotation axis 131 of the drive roller 13. The pressure roller drive unit 50 includes a guide 51 that is elongated in the paper width direction A pair of belts 54a and 54b extending parallel to the roller surface 135, rollers 55a and 55b over which the belts 54a and 54b are stretched, and a motor that rotates the rollers 55a and 55b to move the belts 54a and 54b. 56a and 56b, a connecting portion 57a that connects the belt 54a to the shaft 53a, and a connecting portion 57b that connects the belt 54b to the case C of the roller 15b.

The solenoid 52 can vary the force that urges both ends of the guide 51 toward the roller surface 135, thereby adjusting the pressing force of the pressure rollers 15a and 15b against the printing paper 9.

Motors 56a and 56b also move belts 54a and 54b to change the position of pressure rollers 15a and 15b on roller surfaces 135 in the paper width direction X.

FIG. 3 is a control block diagram showing connections between the control section 40 and each section of the printing apparatus 1. As shown in FIG. As shown in FIG. 3, the control unit 40 is communicably connected to the above-described transport mechanism 10, image recording unit 20, press roller drive unit 50, and input unit 60 that functions as an interface with the operator. There is.

The control unit 40 temporarily reads out the computer program P and data D stored in the storage unit 403 into the memory 402 (see FIG. 1), and based on the computer program P and data D, executes the processing in the arithmetic processing unit 401 (see FIG. 1) controls the operation of each part of the printing apparatus 1 by performing arithmetic processing. As a result, the printing process in the printing device 1 and the drive control of the pressure rollers 15a and 15b, which will be described later, proceed.

Further, as conceptually shown in FIG. 3, the control section 40 includes a conveyance control section 41, a head control section 42, and a pressure roller control section 43. The functions of each of these parts are realized by a computer serving as the control part 40 operating according to a computer program P.

The conveyance control unit 41 controls the conveyance operation of the printing paper 9 by the conveyance mechanism 10. Specifically, the conveyance control section 41 outputs a drive command signal Sa to the motors connected to the unwinding section 11, the winding section 12, and each drive roller 13. As a result, each motor is driven at a designated rotation speed. When each motor is driven, the printing paper 9 is conveyed along the conveyance path by the rotation of the unwinding section 11, the winding section 12, and the plurality of drive rollers 13.

The head control unit 42 controls the ink droplet ejection operation of each of the four recording heads 21. The head control unit 42 outputs an ejection command signal Sb to the four recording heads 21 based on the submitted image data. The ejection command signal Sb includes information indicating the nozzle from which the ink droplets should be ejected, the size of the ink droplets, and the timing of the ink droplet ejection. Each recording head 21 ejects ink droplets of the specified size at the specified timing from the nozzle specified by the ejection command signal Sb. This causes an image corresponding to the image data to be recorded on the top surface of the printing paper 9.

The control unit 40 is also connected to an input unit 60. Through the input unit 60, the operator can store paper information Sf, including the thickness and width size of the printing paper roll Ro set in the unwinding unit 11, in the memory unit 403 of the control unit 40 (pressure roller control unit 43).

The pressure roller control unit 43 refers to the paper information Sf stored in the storage unit 403 and sends a control signal Sc to the solenoid 52 so as to press the printing paper 9 with a pressing force that corresponds to the thickness of the printing paper 9. Send out. Thereby, the solenoid 52 can press the printing paper 9 with a relatively strong pressing force when the paper is thick, and can press the printing paper 9 with a relatively weak pressing force when the paper is thin.
<2. Regarding pressure roller control>
Next, control of the pressure rollers 15a and 15b in the printing apparatus 1 will be described in more detail with reference to FIGS. 4 and 5.

Figure 4 is a schematic diagram for explaining the correspondence between the paper width of the printing paper 9 wound around the roller surface 135 of the drive roller 13 and the positions of the pressure rollers 15a and 15b.

Figure 4 (a) shows a state in which one sheet of printing paper 9 is wrapped around the roller surface 135 on the -X direction side of the X direction center position PC.

Figure 4 (b) shows a sheet of printing paper 9 wrapped around the roller surface 135 with the X-direction center position PC as its center.

The storage unit 403 stores in advance the positions of the pressure rollers 15a and 15b in the X direction for each paper width of the roll R of the printing paper 9 attached to the unwinding unit 11 of the printing device 1. The operator inputs the paper width of the printing paper 9 from the input unit 60 as paper information Sf. Then, the pressure control unit 43 reads the X-direction positions of the pressure rollers 15a and 15b corresponding to the input paper information Sf from the storage unit 403, and transmits control signals Sd and Se to the motors 56a and 56b. The motors 56a and 56b are driven by control signals Sd and Se to move the pressure rollers 15a and 15b toward a position where the printing paper 9 can be stably conveyed between them and the drive roller 15.

That is, when one sheet of printing paper 9 is wrapped around the roller surface 135 on the −X direction side with respect to the X direction center position PC, as shown in FIG. 4(a), the pressure roller 15a is moved to position P12, Press roller 15b is moved to position P10. As a result, one sheet of printing paper 9 is pressed at two different locations in the X-axis direction by the pressing rollers 15a and 15b.

Furthermore, when a sheet of printing paper 9 is wrapped around the roller surface 135 around the center position PC in the X direction, the pressure roller 15a is moved to position P11 and the pressure is Move the roller 15b to position P21. As a result, one sheet of printing paper 9 is pressed by the pressing rollers 15a and 15b at two different locations distributed around the center position PC.

Figure 5 is a schematic diagram for explaining the control of changing the positions of the pressure rollers 15a and 15b according to the position of the image to be printed on the printing paper 9 when a sheet of printing paper 9 is wrapped around the roller surface 135 of the drive roller 13.

Figure 5 (a) shows the standard positions of pressure rollers 15a and 15b when one sheet of printing paper 9 is wrapped around roller surface 135. That is, pressure roller 15a is positioned at standard position P11, and pressure roller 15b is positioned at standard position P21 to press against printing paper 9.

FIG. 5B shows the positions of the pressing rollers 15a and 15b in the X direction when a plurality of pages Pa1 and Pa2 are imposed on the printing paper 9. That is, the pressure roller 15a is positioned at a position that does not overlap with the page Pa1 on the printing paper 9 (a position on the -X direction side of the standard position P11). Similarly, the pressure roller 15b is positioned at a position that does not overlap with the page Pa2 on the printing paper 9 (a position on the +X direction side of the standard position P21).

Information regarding the position of page Pa1 on the printing paper 9 is stored as image data in the storage unit 403. The pressure roller control unit 43 can identify the position of page Pa1 on the printing paper 9 by referring to this image data, and control the motors 56a and 56b so that the pressure rollers 15a and 15b move to positions that do not overlap the position of page Pa1.

Ink ejected from the recording head 21 adheres to pages Pa1 and Pa2. Therefore, when the pressure rollers 15a and 15b press the pages Pa1 and Pa2, there is a risk that ink adhering to the pages Pa1 and Pa2 will be transferred to the pressure rollers 15a and 15b. On the other hand, if the pressure rollers 15a and 15b are moved to the position shown in FIG. 5(b), ink transfer from pages Pa1 and Pa2 to the pressure rollers 15a and 15b can be avoided, and the printing paper 9 can be stably conveyed. You will be able to do this.

FIG. 5C shows the positions of the pressing rollers 15a and 15b in the X direction when one page Pa1 including a plurality of image parts IM1, IM2, and IM3 is imposed on the printing paper 9. That is, the pressing roller 15a is positioned at a gap position between the image components IM1 and IM2 on the page Pa1 (a position on the +X direction side of the standard position P11). Similarly, the pressing roller 15b is positioned at a gap position between the image components IM2 and IM3 on the printing paper 9 (a position on the −X direction side with respect to the standard position P21).

Information regarding the positions of image parts IM1 to IM3 on the printing paper 9 is stored as image data in the storage unit 403. The pressure roller control unit 43 can identify the positions of image parts IM1 to IM3 on the printing paper 9 by referring to this image data, and control the motors 56a and 56b so that the pressure rollers 15a and 15b move to positions that do not overlap the positions of image parts IM1 to IM3.

Since the ink ejected from the recording head 21 is attached to the image components IM1 to IM3, when the pressure rollers 15a and 15b press the image components IM1 to IM3, the ink of the image components IM1 to IM3 is applied to the pressure rollers 15a and 15b. There is a risk of transfer. On the other hand, if the pressure rollers 15a and 15b are moved to the position shown in FIG. 5(c), ink transfer to the pressure rollers 15a and 15b can be avoided, and the printing paper 9 can be stably transported. .

In Figures 5(b) and 5(c), the pressure rollers 15a and 15b are moved to positions offset from the standard positions P11 and P21 to avoid ink transfer to the pressure rollers 15a and 15b. However, if they are shifted too far, the balance of the pressure forces may be lost, and the printing paper 9 may not be transported stably. Therefore, an upper limit threshold for the amount of movement from the standard positions P11 and P21 may be set in advance, and the pressure rollers 15a and 15b may be moved within a range that does not exceed this upper limit.

In addition, if there are multiple candidate positions that do not overlap with page Pa or image part IM, the pressure rollers 15a and 15b may be moved toward the candidate position with the lowest ink density. For example, in the example of FIG. 5(c), it is possible to prevent overlap between the pressure roller 15b and image part IM3 by moving the pressure roller 15b to either the +X side or the -X side of the standard position P21. However, when the pressure roller 15b is moved to the +X side, a part of the pressure roller 15b overlaps with the image part IM3, as shown by the imaginary line in FIG. 5(c). For this reason, it is desirable for the pressure roller control unit 43 to move the pressure roller 15b to a position where there is less overlap with the image part IM3 (the position shown by the solid line in FIG. 5(c)).

Furthermore, depending on the image data, there may be no gaps between the image parts IM. For example, in the example of FIG. 5D, four image parts IM1 to IM4 are printed on page Pa1, but there are no gaps between the image parts IM. In this case, it is desirable to move the pressing roller 15 so that it overlaps the image part IM with the lower ink density among the adjacent image parts IM. That is, the pressing roller 15a is moved to a position where it overlaps the image part IM2 because the latter has a lower ink density than the image part IM1 and the adjacent image part IM2. As for the pressing roller 15b, the pressing roller 15b is moved to a position where it overlaps the image part IM3 because the former has a lower ink density than the image part IM3 and the image part IM4. That is, the pressing roller control unit 43 identifies the high-density image part IM (here, image part IM4) to be printed on the printing paper 9 based on the image data, and controls the motor 56b so that the pressing roller 15b moves to a position where it can avoid the position where the image part IM4 exists.
3. Modifications
In the above embodiment, two pressure rollers 15 are arranged, but the number of pressure rollers 15 may be one.

In the embodiment described above, there are three drive rollers 13 on the conveyance path, and the positions of all the pressure rollers 15 attached to these three drive rollers 13 are changed according to image data. However, the position of the pressing roller 15 may be changed only for the two drive rollers 13 disposed downstream of the image recording unit 20 in the conveyance direction, depending on the image data.

1 Printing device 9 Printing paper 10 Conveying mechanism 11 Unwinding section 12 Winding section 13 Drive roller 14 Followed roller 15 Press roller 20 Image recording section 30 Drying section 40 Control section 50 Press roller drive section 60 Input section

Claims (2)

An inkjet printing device including a substrate transport section including a drive roller and a pressure roller that presses a substrate against a surface of the drive roller, and an image recording section that records an image by ejecting ink droplets according to image data onto the substrate transported by the substrate transport section,
a pressure roller moving member that moves the pressure roller in a direction parallel to a rotation axis of the drive roller; and a pressure roller control unit that controls the pressure roller moving member by referring to the image data,
a standard position of the pressure roller is set in advance for each width size of the base material to be supplied to the drive roller, and the pressure roller control unit refers to the image data and determines whether or not to move the pressure roller from the standard position;
The pressure roller control unit refers to the image data and determines not to move the pressure roller from the standard position when a movement amount of the pressure roller from the standard position is equal to or greater than a threshold value. 2. The inkjet printing apparatus according to claim 1 , further comprising a pressure varying means for varying the pressure of the pressure roller against the substrate in accordance with a thickness of the substrate being used.

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