JP2001239652A - Printer and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always uniformize a distribution of dots of ink when printing is performed on a solid type object to be printed. SOLUTION: The printing is performed on the solid type object 9 to be printed in such a manner that an ejection head 50 for ejecting the ink for printing by an ink jet method is moved in a main scanning direction X and in a sub-scanning direction Y with respect to the object 9 and the ink is ejected from an ejection nozzle provided on the ejection head 50. At that time, an ejection pattern of the ink during the movement of the ejection nozzle with respect to each of the main scanning direction X and the sub-scanning direction Y is controlled corresponding to the inclination of the object 9 with respect to the position of the ejection head 50. More specifically, the operation mode is determined with respect to each of the main scanning direction X and the sub-scanning direction Y corresponding to the inclination angle of the inclined face in each of the main scanning direction X and the sub-scanning direction Y and the printing operation is performed based on the operation mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printing apparatus and a printing method for printing on a three-dimensional printing object.

[0002]

2. Description of the Related Art Conventionally, there has been known a printing apparatus which prints a desired image or the like by discharging ink on a printing paper by an ink jet method or the like. In such a printing apparatus, the ink is ejected while the ejection head for ejecting the ink is continuously moved in the main scanning direction, and when the printing of one line in the main scanning direction is completed, the sub-scanning direction orthogonal to the main scanning direction is completed. The discharge head is moved in the scanning direction by a fixed interval, and a printing operation in the next main scanning direction is started.

Attempts have been made to perform three-dimensional printing on an object to be printed using such a technique of discharging ink such as an ink jet system.

[0004]

However, when printing is performed by ejecting ink from the ejection head in the form of fine droplets onto a three-dimensional printing object, the dot density changes according to the surface shape of the printing object. There is a problem. That is,
When printing a portion of the printing object close to the horizontal plane, a high-density dot distribution can be formed as in the case of printing on a flat surface such as printing paper, but the inclined surface of the printing object is When printing, the dot distribution becomes coarse in accordance with the inclination angle.

FIGS. 16A and 16B are diagrams showing a conventional printing method for explaining this phenomenon. FIG. 16A shows a dot distribution when printing is performed on a horizontal plane, and FIG. This shows the dot distribution in the case of performing. In a conventional printing apparatus, when printing on a three-dimensional printing target, even if the printing target portion is a horizontal surface or an inclined surface, the printing target portion moves stepwise at regular intervals in the sub-scanning direction. Was something. The fixed interval is set to an interval d such that the dot distribution becomes dense when printing is performed on a horizontal plane as shown in FIG. Therefore, if the print target portion is an inclined surface having an inclination angle θ in the sub-scanning direction, and if the print target portion moves at a constant interval d in the sub-scanning direction as shown in FIG. The interval becomes d / cos θ, and the dot distribution becomes coarse.

This is also true for the main scanning direction in which the ejection head continuously moves. However, since the ejection head continuously moves in the main scanning direction, it is possible to relatively easily cope with the situation by controlling the timing of ejecting ink from the ejection head.

On the other hand, the driving in the sub-scanning direction is performed stepwise after continuous printing in the main scanning direction is performed. Can not do it.

On the other hand, when the printing object has an inclination in the sub-scanning direction, the ejection head is inclined according to the inclined surface so that ink is always ejected from the normal direction of the inclined surface, On the other hand, it is conceivable to perform sub-scanning at a constant interval d. However, if such a configuration is adopted, there is a problem that a driving mechanism and operation control become complicated, and the apparatus becomes large.

In view of the above, the present invention has been made in view of the above-mentioned problems, and has a printing apparatus capable of always maintaining a uniform dot distribution of ink when printing on a three-dimensional printing object. And a printing method.

[0010]

According to an aspect of the present invention, there is provided a printing apparatus for performing printing on a three-dimensional printing object, wherein the printing apparatus performs printing on the three-dimensional printing object. An ejection head having ejection nozzles for ejecting printing ink, main scanning direction driving means for continuously moving the ejection head along a predetermined main scanning direction, and sub-scanning orthogonal to the main scanning direction. Sub-scanning direction driving means for moving the ejection head in a stepwise manner along the direction, and in the main scanning direction and the sub-scanning direction, respectively, in accordance with the inclination of the printing object corresponding to the position of the ejection nozzle. Control means for controlling the ink ejection pattern in the process of moving the ejection nozzle.

According to a second aspect of the present invention, in the printing apparatus according to the first aspect, the control means corresponds to a position of the discharge nozzle and corresponds to an inclination of the printing target in the sub-scanning direction. The sub-scanning direction driving means changes a stepwise moving interval when the ejection head moves in the sub-scanning direction.

According to a third aspect of the present invention, in the printing apparatus according to the second aspect, the sub-scanning direction driving unit operates until the moving amount of the ejection head in the sub-scanning direction matches the moving interval. It is characterized in that driving for each minute pitch is repeated.

According to a fourth aspect of the present invention, in the printing apparatus according to the second or third aspect, the control means includes:
When the ejection nozzle is located at a position corresponding to a horizontal plane in the sub-scanning direction on the printing target, the movement interval is set to a predetermined interval, and the ejection nozzle is set in the sub-scanning direction on the printing target. When the position is at a position corresponding to the inclined portion, the movement interval is set to an interval smaller than the predetermined interval according to the inclination angle of the inclined portion along the sub-scanning direction.

According to a fifth aspect of the present invention, in the printing apparatus according to the third aspect, the control unit is configured to control the sub-scanning direction driving unit to drive the ejection head at every minute pitch. When the movement amount of the ejection head in the sub-scanning direction does not match the movement interval, the main scanning direction driving unit is not driven.

According to a sixth aspect of the present invention, in the printing apparatus according to the third or fifth aspect, the minute pitch is variable.

According to a seventh aspect of the present invention, in the printing apparatus according to any one of the first to sixth aspects, the control means approximates a surface shape of the printing object by a plurality of polygons, and An ejection pattern of the ink in the process of moving the ejection nozzle in each of the main scanning direction and the sub-scanning direction is determined for each polygon.

According to an eighth aspect of the present invention, in the printing apparatus according to any one of the first to seventh aspects, the ejection head is rotated in a plane defined by the main scanning direction and the sub-scanning direction. The apparatus further comprises an ejection head rotation driving unit for causing the ejection head to be configured by arranging a plurality of the ejection nozzles in the plane.

According to a ninth aspect of the present invention, in the printing apparatus according to the eighth aspect, the ejection head includes a nozzle array member in which the plurality of ejection nozzles are arranged in the sub-scanning direction for each of a plurality of color components. Provided, each nozzle array member is interconnected by a link mechanism, the link mechanism,
The plurality of nozzle array members are connected to each other such that the nozzle positional relationship in the sub-scanning direction does not deviate between the plurality of color components when the ejection head is rotationally driven by the ejection head rotation driving unit. It is characterized by.

According to a tenth aspect of the present invention, there is provided a printing method for performing printing on a three-dimensional printing object, wherein (a) the ejection head is moved in the main scanning direction and in accordance with the inclination of the printing object. A step of determining an ink ejection pattern from an ejection nozzle in a process of moving in each of the sub-scanning directions, and (b) based on the ejection pattern, the ejection nozzle provided for the printing target, While controlling the continuous movement of the ejection head in the main scanning direction and the stepwise movement in the sub-scanning direction orthogonal to the main scanning direction, the ejection head controls the ejection of the ink to the printing target. And printing.

According to an eleventh aspect of the present invention, in the printing method according to the tenth aspect, the step (a) is performed in the sub-scanning direction corresponding to the position of the discharge nozzle when printing is performed. Determining the ejection pattern so as to change a stepwise movement interval when the ejection head is moved in the sub-scanning direction according to the inclination of the object;
(b) is characterized in that stepwise movement of the ejection head in the sub-scanning direction is controlled based on the movement interval.

According to a twelfth aspect of the present invention, in the printing method of the eleventh aspect, the step (b) is performed until the amount of movement of the ejection head in the sub-scanning direction coincides with the movement interval. It is characterized in that driving for each pitch is repeatedly performed.

According to a thirteenth aspect of the present invention, in the printing method according to the eleventh or twelfth aspect, the printing method is provided.
(a), when the ejection nozzle is located at a position corresponding to a horizontal plane in the sub-scanning direction on the printing target, the movement interval is set to a predetermined interval, and the ejection nozzle is the printing target. When the position is located at a position corresponding to the inclined portion in the sub-scanning direction, an interval smaller than the predetermined interval is set according to the inclination angle of the inclined portion along the sub-scanning direction.

According to a fourteenth aspect of the present invention, in the printing method according to the twelfth aspect, the step (b) is performed in the sub-scanning direction when the ejection head is driven at every minute pitch. When the movement amount of the ejection head does not coincide with the movement interval, the ejection head is not continuously moved in the main scanning direction.

According to a fifteenth aspect of the present invention, in the printing method according to the twelfth or fourteenth aspect, the minute pitch is variable.

According to a sixteenth aspect of the present invention, in the printing method according to any one of the tenth to fifteenth aspects,
In the step (a), the surface shape of the printing target is approximated by a plurality of polygons, and the ejection pattern in the process of moving the ejection nozzles in each of the main scanning direction and the sub-scanning direction is determined for each polygon. It is characterized by the decision.

According to a seventeenth aspect of the present invention, in the printing method according to any one of the tenth to sixteenth aspects,
In the step (b), the ejection head having a configuration in which a plurality of ejection nozzles are arranged in a plane defined by the main scanning direction and the sub-scanning direction is rotated in the plane based on the ejection pattern. It is characterized by including a step.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

<1. Overall Configuration of Printing Apparatus> FIG. 1 is an external view showing a printing apparatus 1 according to an embodiment of the present invention. In this embodiment, three orthogonal axes X, Y, and Z are defined as shown in FIG.

The printing apparatus 1 is provided with a stage 82 for mounting the printing object 9 at a central position on the upper surface side of the base 81. The stage 82 on the base 81 is provided outside the stage 82 along the Y-axis direction. Thus, two grooves 83 are formed. A stand 21 is installed in each of the two grooves 83. The stand 21 is moved in a direction along the groove 83 by the sub-scanning direction driving unit 20 (see FIG. 7) provided inside the base 81 (that is, the stand 21). (Y direction).
A rail 11 is mounted on the upper side of the stand 21, and a head holding mechanism 13 is installed on the rail 11. The main scanning direction driving unit 10 is provided inside the rail 11.
(See FIG. 7), and the main scanning direction driving unit 10 is provided.
Thereby, the head holding mechanism 13 is movable in a direction along the rail 11 (that is, in the X direction). Also,
Inside the head holding mechanism 13, the ejection head rotation drive unit 3 is provided.
0 (see FIG. 7). Further, the head holding mechanism 13 has a drive unit for moving the head 50 up and down. It descends during printing and rises when replacing objects.

An ejection head 50 is connected to a lower portion of the head holding mechanism 13 via a rotation shaft 31 that can be rotated by an ejection head rotation drive unit 30. Discharge head 50
Has a nozzle arrangement section 51 for discharging printing ink to the printing object 9 by an ink jet method or the like. Then, the print object 9 of the nozzle arrangement unit 51
An ejection nozzle for ejecting ink is provided on the surface side opposite to. A discharge nozzle drive unit 60 (see FIG. 7) for driving the discharge nozzle is disposed inside the discharge head 50, and the discharge nozzle drive unit 60 discharges the ink toward the print target 9. In this embodiment, the ink is ejected from the ejection nozzle vertically downward with respect to the XY plane.

FIG. 2 is a diagram showing the positional relationship between the ejection head 50 and the print object 9. The printing apparatus 1 shown in FIG. 1 performs a printing operation while moving the ejection head 50 with respect to the printing target 9 with the X direction as a main scanning direction and the Y direction orthogonal to the X direction as a sub scanning direction. That is, while continuously moving the ejection head 50 along the main scanning direction X,
By discharging ink from the discharge nozzles of the discharge head 50, printing for one line in the main scanning direction X is performed. When one printing operation in the main scanning direction X is completed, the next sub-scanning direction is performed. The ejection head 50 is moved to Y, and the printing operation in the next main scanning direction X is started.

In the printing apparatus 1, the position where the ink in the form of fine droplets ejected from the ejection nozzles of the ejection head 50 lands on the printing target (ie,
In accordance with the inclination of the discharge nozzle in the discharge head 50 (the position corresponding to the current position of the discharge nozzle), the ink discharge pattern in the process of moving the discharge nozzle in each of the main scanning direction X and the sub-scanning direction Y is controlled. Accordingly, the dot distribution is realized in the main scanning direction X and the sub-scanning direction Y on the printing target so as to be uniform.

<2. Discharge Pattern Control in the Sub-Scanning Direction Y> First, discharge pattern control in the sub-scanning direction Y will be described.

FIGS. 3A and 3B show the principle for making the dot distribution uniform in the sub-scanning direction Y. FIG. 3A shows the case where printing is performed on a horizontal plane in the sub-scanning direction Y.
(B) shows a case where printing is performed on an inclined surface having an inclination angle θ in the sub-scanning direction Y. The term “horizontal” means parallel to the Y axis, and the term “inclined surface”
Is not parallel to the axis.

As shown in FIG. 3 (a), when printing on a horizontal plane of the print object 9, in order to make the dot distribution dense in the sub-scanning direction Y, the moving interval in the sub-scanning direction Y Is set as the interval d as in the conventional case. As a result, in the horizontal plane portion, the dot interval due to the ink that has landed on the print target 9 is d, and a high-definition print result is obtained.

On the other hand, as shown in FIG. 3B, when printing is performed on the inclined surface of the printing object 9, the sub-scanning is performed in order to make the dot distribution in the sub-scanning direction Y dense on the inclined surface. The movement interval in the direction Y is set to an interval dcos corresponding to the inclination angle θ.
Set as θ. Then, by starting the printing operation in the main scanning direction X, the dot interval in the sub-scanning direction Y becomes d on the inclined surface, and matches the dot interval d when printing on a horizontal plane portion. As a result, a high-definition printing result can be obtained even on an inclined surface.

That is, in the printing apparatus 1, the movement interval in the sub-scanning direction Y can be changed.
Is moved stepwise in the sub-scanning direction Y, the moving interval is changed according to the inclination in the sub-scanning direction Y. Specifically, in the sub-scanning direction Y, when the movement interval when printing on a horizontal plane is d, and when the inclination angle in the sub-scanning direction Y is θ, the ejection head 50 in the sub-scanning direction Y Is set as dcos θ, the dot distribution interval in the sub-scanning direction Y becomes d regardless of the shape of the surface of the printing object 9, and the uniform dot distribution state becomes can get.

FIG. 4 is a diagram showing a specific driving method for realizing the movement interval L in the sub-scanning direction Y. FIG. 4A shows a case where printing is performed on a horizontal plane in the sub-scanning direction Y.
(B) shows a case where printing is performed on an inclined surface having an inclination angle of 30 ° in the sub-scanning direction Y, (c) shows a case where printing is performed on an inclined surface having an inclination angle of 45 °, and (d) shows an inclined surface having an inclination angle of 60 ° In each case.

The printing apparatus 1 is configured so that the ejection head 50 can be moved in the sub-scanning direction Y with the fine pitch p as a drive unit. This minute pitch p is
This is the minimum drive unit when the ejection head 50 is moved in the sub-scanning direction Y in the printing apparatus 1, and is set to a value smaller than the movement interval L (= d) when printing on a horizontal plane. You. In this embodiment, as shown in FIG. 4, the minute pitch p is set as d / 10.

In the printing apparatus 1, when the control unit 43 (see FIG. 7), which will be described later, determines the movement interval L according to the inclined surface, the dot interval formed by ink landing on the inclined surface is determined by the following formula. An accumulation coefficient of the minute pitch p closest to the dot interval d on the horizontal plane is obtained, and the value is set as the movement interval L.

More specifically, as shown in FIG. 4A, when printing is performed on a horizontal plane of the printing object 9, the dot interval on the horizontal plane may be d, so L is d
Is set as

Next, as shown in FIG. 4B, when printing is performed on an inclined surface of the printing object 9 having an inclination angle of 30 °, the dot interval on the inclined surface is closest to d. Is determined as follows. Here, when the movement is performed every fine pitch p eight times and the movement interval L is set to 8d / 10, the dot interval on the inclined surface is about 0.92d, and the movement is performed nine times every fine pitch p. Interval L is 9d / 10
, The dot interval on the inclined surface is about 1.04d
In this case, the moving distance L is set to 9d / 10 so as to be closest to the dot distance d on the horizontal plane.

Next, as shown in FIG. 4C, when printing is performed on an inclined surface of the print object 9 having an inclination angle of 45 °, the dot interval on the inclined surface becomes closest to d. Thus, the movement interval L is set as 7d / 10. in this case,
The dot interval on the inclined surface is about 0.99d.

Next, as shown in FIG. 4D, even when printing is performed on an inclined surface of the printing object 9 having an inclination angle of 60 °, the dot interval on the inclined surface is closest to d. Is determined as described above, and in this case, it is set as 5d / 10. Further, in this case, the dot interval on the inclined surface matches the dot interval d on the horizontal plane.

Therefore, in the printing apparatus 1, by setting the minute pitch p, which is a drive unit in the sub-scanning direction Y, smaller than the dot interval formed on the surface of the printing object 9, even on an inclined surface. The dot interval of the landed ink in the sub-scanning direction Y can be maintained at a substantially constant value, and high-definition printing can be realized also in the sub-scanning direction Y.

Here, when actually performing the printing operation by moving the discharge head 50 with respect to the printing object 9, two operation modes are conceivable.

First, the discharge head 50 is driven in the main scanning direction X every time the stepwise movement of the fine pitch p is performed in the sub-scanning direction Y. In the case of this operation mode, when the main scanning direction driving unit 10 and the sub-scanning direction driving unit 20 relatively move the ejection head 50 with respect to the printing target 9, Each time the driving in the sub-scanning direction Y is performed, the driving in the main scanning direction X may be repeated. And
If the ejection nozzles of the ejection head 50 are configured to selectively eject necessary ink when reaching a predetermined ink ejection position above the printing target 9, printing on the printing target 9 can be performed.

Therefore, in the case of the first operation mode,
There is no need to transmit information about the movement interval L to the sub-scanning direction drive unit 20, and the ejection head 50
The driving system for moving in the sub-scanning direction Y only needs to perform a steady driving operation, so that a mechanism for controlling the driving system can be simplified.

In the case of the first mode of operation, when there are a plurality of types of inclined surfaces in the main scanning direction X at a certain sub-scanning position, in particular, the shape of the printing object 9 has a continuous curved surface or the like. It is effective when. Because, when the ejection head 50 is at such a sub-scanning position,
The movement interval L for realizing the optimal dot interval is set for each inclined surface. By driving the ejection head 50 at every minute pitch p which is the minimum drive unit in the sub-scanning direction Y, This is because there may be an inclined surface whose sub-scanning position after the movement matches the set movement interval L. Therefore, the movement in the sub-scanning direction Y for each minute pitch p and the driving in the main scanning direction X are alternately and repeatedly performed, so that a printing target having a complicated three-dimensional shape is stabilized. The printing operation can be performed.

However, on the other hand, in the case of the first mode of operation, when the movement to the sub-scanning position Y is performed at every fine pitch p, the movement interval L set at the sub-scanning position is coincident. There may be no slope. In this case, the driving in the main scanning direction X performed at the sub-scanning position does not involve the ink discharging operation, and thus becomes a factor that hinders the printing efficiency.

Therefore, the second mode of operation is effective to open such a reduction in printing efficiency.

In the second mode of operation, the driving of the ejection head 50 is repeated every minute pitch p until the amount of movement of the ejection head 50 in the sub-scanning direction Y matches the movement interval L. If the movement amount of the ejection head 50 in the sub-scanning direction Y does not match the movement interval L when driven, the operation in the main scanning direction X is not performed. That is, in this operation mode, as in the first operation mode, the drive in the sub-scanning direction Y is repeatedly performed for each fine pitch p. Discharge head 5
The operation of 0 is not performed.

Therefore, according to the second operation mode, the driving in the main scanning direction X is not performed when the ink is not ejected, so that the operation time for the driving can be omitted and the printing is required. This shortens the time, improves the printing efficiency, and enables high-speed printing.

<3. Ejection Pattern Control in Main Scanning Direction X> Next, ejection pattern control in the main scanning direction X will be described. In the main scanning direction X, the ejection head 50 is configured to perform continuous movement instead of stepwise movement. Therefore, as a method for making the dot distribution uniform in the main scanning direction X, A method of changing the speed at which the continuous movement is performed in accordance with the inclined surface in the main scanning direction X, and a method of discharging the ink while maintaining the speed at the time of the continuous movement (i.e., Drive frequency) according to the inclined surface.

FIGS. 5A and 5B are diagrams showing a first method relating to ejection pattern control in the main scanning direction X. FIG. 5A shows a case where printing is performed on a horizontal plane in the main scanning direction X, and FIG.
Indicates a case where printing is performed on an inclined surface having an inclination angle θ in the main scanning direction X.

In this operation example, the moving speed V when the ejection head 50 continuously moves in the main scanning direction X is changed according to the inclined surface in the main scanning direction X.

That is, when the ejection head 50 is moved to eject ink on a horizontal plane in the main scanning direction X, the ejection head 50 is moved at the main scanning speed V as shown in FIG. On the other hand, when the ejection head 50 is moved to eject ink on an inclined surface having an inclination angle θ in the main scanning direction X, the speed of the ejection head 50 is set to the inclination angle θ as shown in FIG. Main scanning speed Vc according to
osθ.

For example, with respect to a horizontal plane, the main scanning direction X
In order to make the dot interval d uniform at d, the driving frequency for driving the ejection nozzles to the ejection head 50 moving at the main scanning speed V as shown in FIG. ). In order for the ejection head 50 to form a uniform dot distribution with a dot interval d on an inclined surface having an inclination angle θ, the driving frequency f
If (Hz) is kept constant, it is necessary to change the moving speed V in the main scanning direction X according to the inclination angle θ. Therefore, in the operation example of FIG. 5B, when the ink is ejected onto the inclined surface having the inclination angle θ, the driving frequency is applied to the inclined surface having the inclination angle θ by setting the main scanning speed to Vcos θ. Even if the ink is ejected without changing f (Hz), the dot interval on the inclined surface is d, and the dot interval d formed on the horizontal plane is d.
Therefore, a uniform dot distribution can be realized.

Next, FIG. 6 is a diagram showing a second method relating to the ejection pattern control in the main scanning direction X. FIG. 6A shows a case where printing is performed on a horizontal plane in the main scanning direction X.
(B) shows a case where printing is performed on an inclined surface having an inclination angle θ in the main scanning direction X.

In this operation example, the moving speed V when the discharge head 50 continuously moves along the main scanning direction X is kept constant, and the discharge nozzle 50 is moved from the discharge nozzle in accordance with the inclined surface in the main scanning direction X. The ink ejection timing, that is, the drive frequency is changed.

That is, the continuous moving speed in the main scanning direction X, that is, the main scanning speed is kept constant at V. When ink is ejected on a horizontal plane in the main scanning direction X, As shown in FIG. 6A, while setting the drive frequency of the discharge nozzle in the discharge head 50 to f, when discharging ink onto an inclined surface having an inclination angle θ in the main scanning direction X, FIG. As shown in FIG.
Drive frequency of the discharge nozzle at f according to the inclination angle θ
/ Cos θ.

For example, a main scanning direction X with respect to a horizontal plane
In order to make the dot interval of d uniform with d, the driving frequency for driving the ejection nozzles with respect to the ejection head 50 moving at the main scanning speed V as shown in FIG. ). Then, while keeping the main scanning speed V constant, the ejection head 50 is tilted at the inclination angle θ.
In order to form a uniform dot distribution with a dot interval d on an inclined surface having the following, it is necessary to change the drive frequency in accordance with the inclination angle θ. Therefore, in the operation example of FIG. 6B, when the ink is ejected to the inclined surface having the inclination angle θ, the driving frequency of the ejection nozzle is changed to the inclination having the inclination angle θ while maintaining the main scanning speed at V. F / cos θ (H
By changing to z), the dot interval on the inclined surface becomes d, which coincides with the dot interval d formed on a horizontal plane, so that a uniform dot distribution can be realized.

As described above, in the main scanning direction X, the discharge head 50 is configured not to move stepwise but to move continuously, so that the dot distribution is made uniform in the main scanning direction X. If any one of the above two operation examples is adopted for this purpose, the dot interval in the main scanning direction X can be kept uniform regardless of the presence or absence of the inclination.

<4. Control Mechanism and Overall Operation in Printing Apparatus 1> Next, the control mechanism in printing apparatus 1 will be described.

FIG. 7 is a block diagram showing a control mechanism in the printing apparatus 1. As shown in FIG. 7, the printing device 1
Image data receiving section 41, shape data receiving section 42, control section 43, RAM 44, ROM 45, main scanning direction driving section 1
0, sub-scanning direction drive unit 20, ejection head rotation drive unit 3
0, various sensors 47 and a discharge nozzle driving unit 60. The image data receiving unit 41 receives image data representing the content of printing on the printing object 9 as an image from an externally connected host computer 100, while the shape data receiving unit 42 receives the printing object from the host computer 100. Shape data relating to the surface shape of No. 9 is input.

The control unit 43 determines an ejection pattern for ejecting printing ink in each of the main scanning direction X and the sub-scanning direction Y in order to perform a printing operation on the printing object 9, By controlling the main scanning direction driving unit 10, the sub-scanning direction driving unit 20, the ejection nozzle driving unit 60, and the like based on the determined ejection pattern, a uniform dot distribution is realized on the printing target 9. .
The RAM 44 is a memory for storing image data and shape data input from the host computer 100, and ejection pattern data for printing operation control, such as data relating to the movement interval L in the sub-scanning direction Y. The ROM 45 is a memory that stores a program corresponding to a printing operation procedure (a flowchart of FIG. 8 described later) executed by the control unit 43.

The main scanning direction driving unit 10 is provided with a rail 11 (FIG. 1).
The head holding mechanism 13 can be moved along the rail 11 by driving a predetermined motor or the like based on an operation command from the control unit 43. Move along the main scanning direction X.

The sub-scanning direction drive unit 20 is provided inside the base 81 (see FIG. 1), and drives a predetermined motor or the like based on an operation command from the control unit 43 to move the stand 21 in the Y direction. The ejection head 50 can be moved along the sub-scanning direction Y.

The discharge head rotation drive section 30 is provided inside the head holding mechanism 13 and rotates the discharge head 50 in the XY plane based on an operation command from the control section 43. This rotation operation is particularly effective when the ejection head 50 is in a multi-nozzle mode, which will be described later.

Various sensors 47 are provided in the main scanning direction driving section 10.
Detecting means for detecting a home position and the like in each of the operating mechanisms, and detecting the remaining amount of ink in the ejection head 50. This detecting means realizes accurate operation in each direction. In addition, it is possible to grasp the replacement time of the ink tank and the like.

The ejection nozzle driving section 60 is provided in the ejection head 50 and ejects ink from ejection nozzles provided in the ejection head 50 based on ejection timing given from the control section 43.

The operation when printing is actually performed on the three-dimensional printing object 9 in the printing apparatus 1 configured as described above will be described.

FIG. 8 is a flowchart showing the overall operation of the printing apparatus 1, and shows the processing procedure mainly performed in the control unit 43 of the above configuration.

First, in step S11, the print object 9
Is approximated by n (where n is an arbitrary integer) polygon planes. Specifically, the control unit 4
3 inputs shape data on the printing object 9 obtained from the host computer 100, and processes even the printing object 9 having a surface shape such as smooth unevenness to form a plurality of surface shapes. As a set of polygon planes.

FIGS. 9 to 11 are diagrams showing an example of the case where the shape of the printing object 9 performed by the control unit 43 is approximated by a polygon plane. FIG. FIG. 1 shows a case where the object 9 is printed.
0 is a printing object 9 having an inclination only in the sub-scanning direction Y.
FIG. 11 shows a case where the print target 9 having an inclination in both the main scanning direction X and the sub-scanning direction Y is printed.

First, in the case shown in FIG. 9, the shape data on the printing object 9 obtained from the host computer 100 has a smooth curved surface in the main scanning direction X as shown in FIG. 9A. However, in this state,
When the inclination angle in the main scanning direction X is obtained, the inclination angle of the printing object 9 continuously changes with respect to the main scanning direction X. Therefore, it is necessary to obtain the inclination angles for all the ink landing positions. It is necessary to create an ejection pattern for each of them, which requires enormous calculations. Therefore, the control unit 43
In FIG. 9B, the surface shape of the printing object 9 is divided into a plurality of regions in the main scanning direction X as shown in FIG. 9B, and the curved surface of each region is approximated by a polygon using a polygon.
As a result, the curved surface in the main scanning direction X is represented by a plurality of polygon planes, the inclination angle in the main scanning direction X is obtained for each polygon, and the ejection pattern is changed.

In the case shown in FIG. 10, the shape data on the printing object 9 obtained from the host computer 100 has a smooth curved surface in the sub-scanning direction Y as shown in FIG. However, in this state, when the inclination angle in the sub-scanning direction Y is obtained, the inclination angle of the printing object 9 changes continuously with respect to the sub-scanning direction Y. , And it is necessary to create an ejection pattern for each of them, which requires enormous calculations. Therefore, the control unit 43 divides the surface shape of the printing target 9 into a plurality of regions in the sub-scanning direction Y as shown in FIG. 10B, and approximates the curved surface of each region to a plane using polygons. You do it. As a result, the curved surface in the sub-scanning direction Y is represented by a plurality of polygon planes, the inclination angle in the sub-scanning direction Y is obtained for each polygon, and the ejection pattern is changed.

In the case shown in FIG. 11, the shape data on the printing object 9 obtained from the host computer 100 has a smooth curved surface in the main scanning direction X and the sub-scanning direction Y as shown in FIG. Has become. However, in this state, when obtaining the inclination angles in both the main scanning direction X and the sub-scanning direction Y, the inclination angle of the printing object 9 continuously changes with respect to the main scanning direction X and the sub-scanning direction Y. Therefore, it is necessary to find the inclination angles for all the ink landing positions, and it is necessary to create an ejection pattern for each of them, which requires enormous calculations. Therefore, the control unit 43 divides the surface shape of the print target 9 into a plurality of regions as shown in FIG. 11B, and approximates the curved surface of each region to a plane using polygons. As a result, the curved surface of the printing object 9 is represented by a plurality of polygon planes, and the inclination angles in both the main scanning direction X and the sub-scanning direction Y are obtained for each polygon, and the ejection pattern is changed.

In this way, n in step S11
The approximation is performed on individual polygon planes. By performing polygon approximation in this way, it is possible to improve printing efficiency. That is, if polygon approximation is performed, printing conditions and the like for each polygon in the main scanning direction X and the sub-scanning direction Y can be obtained, and the printing operation can be changed for each polygon. If there is, the change of the ejection pattern at the time of the printing operation may be performed n times.

On the other hand, without performing polygon approximation, it is also possible to obtain the inclination angle for each position of each ejection head on a curved surface having a continuous change, and change the ejection pattern each time. However, in this case,
In some cases, it is necessary to change the ejection pattern every time one ink is ejected, so that the control during the printing operation becomes very complicated, and a great deal of time is required for the arithmetic processing and the printing operation. .

Therefore, by performing polygon approximation on the surface to be printed, a printing operation can be performed under the same conditions for each polygon, so that efficient printing can be performed.

Then, the process proceeds to a step S12, wherein the polygon parameter i is initialized to 1. In step S13,
The inclination angle θx of the i-th polygon in the main scanning direction X
Ask for. Then, in step S14, the driving conditions in the main scanning direction X are determined according to the inclination angle θx, and the determined driving conditions are temporarily stored in the RAM 44. Then, in step S15, the polygon parameter i is set to 1
And the process proceeds to step S16. In step S16, it is determined whether or not the driving conditions in the main scanning direction X have been determined for all of the n polygons. If all of the polygons have been completed, the process proceeds to step S17. Returning to step S13, drive conditions are determined for the next polygon.

The processing in steps S12 to S16 is as follows.
This is a process for determining a driving condition in the main scanning direction X for all polygons. And the main scanning direction X
Are determined for all the polygons, the driving conditions for the sub-scanning direction Y (that is, the stepwise movement interval L in the sub-scanning direction Y) are determined in steps S17 to S22. Is performed.

At step S17, the polygon parameter i
Is initialized to 1. In step S18, the inclination angle θy of the i-th polygon in the sub-scanning direction Y is determined.
Then, in step S19, (cos θy-k / 1
An integer k that minimizes the absolute value of 0) is obtained. This integer k
Is a value indicating the cumulative coefficient of movement for each minute pitch p in the sub-scanning direction Y. Then, in step S20,
The moving interval L in the sub-scanning direction Y for setting the dot interval for the i-th polygon to d is set as k × d / 10. That is, when the movement interval L = k × d / 10 for the i-th polygon, the dot interval in the sub-scanning direction Y is closest to the dot interval d on the horizontal plane. The movement interval L determined here is RA
It is temporarily stored in M44. And step S21
The polygon parameter i is incremented by one, and the process proceeds to step S22. In step S22, it is checked whether or not the movement interval L in the sub-scanning direction Y has been determined for all of the n polygons. If all of the polygons have been completed, the process proceeds to step S23. Then, the process returns to step S18 to determine the movement interval for the next polygon.

Then, the processes of steps S23 to S26 are performed in order to perform printing for each polygon.

In step S23, the polygon parameter i is initialized to 1. Then, in step S24, the control unit 43 obtains the drive conditions for the i-th polygon in the main scanning direction X and the movement intervals for the sub-scanning direction Y from the RAM 44, and based on those data, prints the i-th polygon. Printing is performed on the target area surface (the actual surface approximated by the i-th polygon). When the printing operation on the area surface is completed, the polygon parameter i is incremented by 1 in step S25, and the process proceeds to step S26. Step S26
Then, it is checked whether or not the printing operation has been completed for all of the n polygons, and if all of the polygons have been completed, the printing operation for the print object 9 is completed, whereas if not, the process proceeds to step S24. Then, the printing operation for the next polygon is started.

Here, when the printing operation in step S24 is performed, driving is performed in the main scanning direction X based on the driving conditions obtained for each polygon, and ejection is performed in the sub-scanning direction Y. When the head 50 is moved, a stepwise movement is performed based on the movement interval L obtained for each polygon, and the dot intervals in both the main scanning direction X and the sub-scanning direction Y are substantially the same between the polygons. Becomes
A uniform dot distribution is formed.

<5. Multi-Nozzle Mode of Discharge Head> Next, a description will be given of a case where the discharge head 50 has a multi-nozzle configuration including a plurality of discharge nozzles for discharging printing ink. When the ejection head 50 has a multi-nozzle configuration, it is possible to eject a plurality of ink droplets at the same time, so that it has a specific operation and effect that high-speed printing is possible.

When a plurality of ejection nozzles are arranged in the sub-scanning direction Y, the interval between the nozzles is constant in the sub-scanning direction Y. When ink is ejected from the ejection nozzles having such a fixed interval, a gap of dots corresponding to the fixed interval is generated between the respective dots. Therefore, the gap is formed by repeating the driving in the sub-scanning direction Y. You need to fill it with dots.

When printing is performed on a horizontal plane, the moving distance L in the sub-scanning direction Y is set to a distance d (see FIG. 4A) that makes the dot distribution dense. The gap is evenly and appropriately filled with dots.

However, when printing is performed on an inclined surface, the movement interval L in the sub-scanning direction Y is set to an interval that makes the dot distribution dense (see FIGS. 4B to 4D). Therefore, it is impossible to uniformly and properly fill the gaps between the dots generated by the fixed intervals of the ejection nozzle array.

In order to avoid this phenomenon, it is desirable to change the interval between the ejection nozzles in accordance with the inclination in the sub-scanning direction Y. It is technically difficult to realize it freely.

Therefore, the printing apparatus 1 is operated in the sub-scanning direction Y
The discharge head 50 is rotated by the above-described discharge head rotation drive unit 30 in accordance with the inclination angle of, and the arrangement interval of the discharge nozzles in the sub-scanning direction Y is adjusted.

FIG. 12 is a diagram showing the rotation operation of the ejection head 50. As shown in FIG. 12, the ejection head 50 is configured to perform a rotation operation in the XY plane in accordance with the rotation of the rotation shaft 31 by the ejection head rotation drive unit 30. As a result, when a plurality of ejection nozzles are arranged along the sub-scanning direction Y on the lower surface side of the ejection head 50, the nozzle interval in the sub-scanning direction Y can be adjusted.

Hereinafter, the ejection heads 50 having three types of multi-nozzle configurations will be described in detail with reference to FIGS. In the following, in order to perform color printing on the printing object 9, Y (yellow), M
A description will be given of an ejection head 50 having a multi-nozzle configuration including a plurality of ejection nozzles for each color component of (magenta), C (cyan), and K (black).

FIG. 13 is a diagram showing an example of a multi-nozzle configuration in which a plurality of ejection nozzles 52 for each color component of Y, M, C, and K are vertically arranged in the sub-scanning direction Y.

FIG. 13A is a view of the nozzle arrangement portion 51 of the ejection head 50 as viewed from the printing object 9 side. As shown in FIG. 13A, a plurality of ejection nozzles 52 for each of the Y, M, C, and K color components are arranged in a line in a vertical direction (that is, the sub-scanning direction Y) in the nozzle arrangement unit 51. The nozzle groups for each color component are also arranged in the vertical direction.

When an inclined surface having an inclination angle θ in the sub-scanning direction Y is to be printed by such a discharge head 50, the movement interval L in the sub-scanning direction Y is determined according to the inclination angle θ as described above. 13 is given, and the rotation angle θ is given to the ejection head 50.
As shown in (b), the nozzle arrangement part 51 is changed according to the inclination angle θ.
Is to rotate. As a result, the row of ejection nozzles arranged along the sub-scanning direction Y has an angle θ with respect to the sub-scanning direction Y.

FIG. 13 (c) is an enlarged view of the portion A (ie, the discharge nozzle portion) in FIG. 13 (b). Assuming that the physical distance between the nozzles in the nozzle arrangement section 51 is r, the nozzle arrangement section 51 rotates in the sub-scanning direction Y according to the inclination angle θ, so that the nozzle interval in the sub-scanning direction Y becomes rcos θ. And the sub-scanning direction Y
Will be substantially reduced.

By giving the ejection head 50 the same rotation angle as the inclination angle θ of the inclined surface, the dot interval formed by ink ejected from the adjacent ejection nozzles 52 becomes r on the inclined surface. Will be kept. This dot interval r is the same as the dot interval formed by the adjacent ejection nozzles 52 when printing is performed on a horizontal plane by the multi-nozzle mechanism. Therefore, if the printing operation is performed by setting the moving interval L in the sub-scanning direction Y so as to be equivalent to the dot distribution formed on the horizontal plane, the gap in the dot interval r is moved in the sub-scanning direction Y. With this movement, landing dots are uniformly and appropriately formed.

That is, the sub-scanning direction Y depends on the inclination angle θ.
Even if the movement interval L is set to be smaller than that in the case of printing on a horizontal plane, the nozzle interval in the sub-scanning direction Y becomes smaller accordingly, so that the plurality of ejection nozzles 52 are evenly and appropriately. It is possible to fill the gap between the inks ejected from the nozzle with dots. As a result, high-definition printing can be realized.

In this case, however, the rotation of the ejection head 50 changes the positional relationship of each ejection nozzle 52 with respect to the main scanning direction X.
In generating the data for the printing operation (specifically, the data indicating the drive timing of each ejection nozzle), the position change of each ejection nozzle 52 with respect to the main scanning direction X is taken into account beforehand. It is necessary to generate data in which the position change is corrected.

Next, FIG. 14 shows that a plurality of ejection nozzles 52 for each color component of Y, M, C, and K are vertically arranged along the sub-scanning direction Y, and the nozzles for each color component are arranged. FIG. 3 is a diagram illustrating a multi-nozzle configuration example in which groups are arranged in parallel.

FIG. 14A is a view of the nozzle arrangement section 51 of the ejection head 50 as viewed from the printing object 9 side.
As shown in FIG. 14A, Y,
A plurality of ejection nozzles 52 for each of the M, C, and K color components are arranged in a line in the vertical direction (that is, the sub-scanning direction Y), and the nozzle groups for each color component are arranged in the Y direction. They are arranged in parallel.

When the ejection head 50 is to print an inclined surface having an inclination angle θ in the sub-scanning direction Y, the moving distance L in the sub-scanning direction Y is set according to the inclination angle θ as described above. 14 and the rotation angle θ is given to the ejection head 50, and FIG.
As shown in (b), the nozzle arrangement part 51 is changed according to the inclination angle θ.
To rotate. As a result, the row of the ejection nozzles 52 for each color component arranged along the sub-scanning direction Y has an angle θ with respect to the sub-scanning direction Y.

FIG. 14 (c) is an enlarged view of the portion A (ie, the discharge nozzle portion) in FIG. 14 (b). Assuming that the physical distance between the nozzles of the same color component in the nozzle arrangement unit 51 is r, the nozzle arrangement unit 51 rotates in the sub-scanning direction Y in accordance with the inclination angle θ, and The nozzle interval is rcosθ,
The arrangement interval in the sub-scanning direction Y is substantially reduced.

By giving the ejection head 50 the same rotation angle as the inclination angle θ of the inclined surface, the dot interval formed by the ink ejected from the adjacent ejection nozzles 52 becomes r on the inclined surface. Will be kept. This dot interval r is the same as the dot interval formed by the adjacent ejection nozzles 52 when printing is performed on a horizontal plane by the multi-nozzle mechanism. Therefore, if the printing operation is performed by setting the moving interval L in the sub-scanning direction Y so as to be equivalent to the dot distribution formed on the horizontal plane, the gap in the dot interval r is moved in the sub-scanning direction Y. With this movement, landing dots are uniformly and appropriately formed.

However, this is a case where attention is paid to the same color component, and an undesirable situation occurs in relation to other color components. That is, by rotating the nozzle arrangement unit 51 at the angle θ, the K ejection nozzles 52a and the C ejection nozzles 52b, which should originally scan the same sub-scanning position, do not match at the sub-scanning position. , A gap corresponding to the interval e has occurred. Therefore, in this case, printing control for each color component such as starting printing operation for K first and starting printing operation for C at the time when the movement for the interval e is performed in the sub-scanning direction Y is performed. This necessitates a reduction in printing efficiency.

Also in this case, since the position of each ejection nozzle 52 changes in the main scanning direction X, it is necessary to generate data in which the above-described position change in the main scanning direction X is corrected in advance. is there.

FIG. 15 shows the nozzle arrangement members 51y, 51m, 51c, 51k for each of the Y, M, C, K color components.
And the respective nozzle arrangement members 51y, 51m, 5
It is a figure which shows the example of a multi-nozzle structure in which 1c and 51k are connected by the link mechanism 54.

FIG. 15A is a view of the nozzle arrangement portion 51 of the ejection head 50 as viewed from the printing object 9 side.
As shown in FIG. 15A, the nozzle arrangement unit 51 includes Y, M, C, and K color components in which a plurality of ejection nozzles 52 are arranged in a line in the vertical direction (ie, the sub-scanning direction Y). Nozzle arrangement members 51y, 51m, 51c, 51k,
A link mechanism 54 for connecting the nozzle arrangement members 51y, 51m, 51c, and 51k at their ends in the sub-scanning direction is provided. The link mechanism 54 is configured so that when the ejection head rotation drive unit 30 performs the rotation drive, the positional relationship corresponding to the ejection nozzles 52 in the sub-scanning direction Y in each color component does not shift.

When the inclined surface having the inclination angle θ in the sub-scanning direction Y is to be printed by the ejection head 50 having such a nozzle arrangement portion 51, the moving distance L in the sub-scanning direction Y is as described above. The inclination angle θ
And a rotation angle θ is given to the ejection head 50.

FIG. 15B is a view showing the nozzle arrangement section 51 to which the rotation angle θ is given. As shown in FIG. 15B, when the rotation angle θ is given to the nozzle arrangement portion 51 in accordance with the inclination angle θ, the nozzle arrangement members 51y, 51m, 51c, and 51k move by the angle θ by the action of the link mechanism. Just rotate. As a result, the rows of the ejection nozzles 52 of the nozzle arrangement members 51y, 51m, 51c, and 51k arranged along the sub-scanning direction Y have an angle θ with respect to the sub-scanning direction Y.

FIG. 15 (c) is an enlarged view of the portion A (ie, the discharge nozzle portion) in FIG. 15 (b). Assuming that the physical distance between the nozzles of the same color component in the nozzle arrangement unit 51 is r, the nozzle arrangement unit 51 rotates in the sub-scanning direction Y according to the inclination angle θ, thereby The nozzle interval is rcosθ,
The arrangement interval in the sub-scanning direction Y is substantially reduced.

By giving the same rotation angle as the inclination angle θ of the inclined surface to the ejection head 50, the dot interval formed by ink ejected from the adjacent ejection nozzles 52 becomes r on the inclined surface. Will be kept. This dot interval r is the same as the dot interval formed by the adjacent ejection nozzles 52 when printing is performed on a horizontal plane by the multi-nozzle mechanism. Therefore, if the printing operation is performed by setting the moving interval L in the sub-scanning direction Y so as to be equivalent to the dot distribution formed on the horizontal plane, the gap in the dot interval r is moved in the sub-scanning direction Y. With this movement, landing dots are uniformly and appropriately formed.

Further, by the action of the link mechanism 54, each of the nozzle array members 51y, 51m, 51c, 51
There is no positional deviation in the sub-scanning direction Y between the corresponding ejection nozzles at k.

That is, as shown in FIG. 15, the nozzle arrangement section 51 is divided for each ejection nozzle row for each color component, and the nozzle arrangement members 51y, 51m, 51c, 51
By connecting k with the link mechanism 54, it is possible to prevent the displacement of the corresponding ejection nozzle in the sub-scanning direction Y between the respective color components, and to set the distance between the adjacent ejection nozzles 52 in the sub-scanning direction Y. Can be adjusted, and four-color simultaneous printing can be easily performed in one main scan, so that the three-dimensional printing object 9 can be printed most efficiently.

However, also in this case, the main scanning direction X
, The position of each ejection nozzle 52 changes.
It is necessary to generate in advance data in which the position change in the main scanning direction X as described above has been corrected.

<6. Modifications> While the preferred embodiments of the present invention have been described above, the present invention is not limited to those described above.

For example, in the above description, the fine pitch p which is the minimum drive unit in the sub-scanning direction Y
P = d / 1 based on the dot interval d to be formed on the surface of
The case where it is set to 0 has been described, but the present invention is not limited to this.

The fine pitch p is made finer, for example, = d
When set as / 100, it is possible to reduce an error occurring in the dot interval in the sub-scanning direction Y when printing on an inclined surface, and as a result, the dot interval d when printing on a horizontal plane is more accurate. It is possible to get closer. That is, if the minute pitch p is set to a small value, the uniformity of dots in the sub-scanning direction Y is improved accordingly, and high-definition printing becomes possible.

On the other hand, if the minute pitch p is set to a small value, the stepwise movement in the sub-scanning direction Y is a minute operation correspondingly, so that the printing efficiency is reduced.

Therefore, the minimum drive unit in the sub-scanning direction drive unit 20 is configured to be freely changeable, and the control unit 43 performs the printing operation according to the print quality and print speed desired by the user. It is preferable to determine the minute pitch p to be set at this time and to transmit the determined minute pitch p to the sub-scanning direction driving unit 20. That is, in this case, the balance between the print image quality and the print speed that are in a trade-off relationship can be set to what the user intends.

[0124]

As described above, according to the first aspect of the present invention, ejection is performed in each of the main scanning direction and the sub-scanning direction according to the inclination of the printing object corresponding to the position of the ejection nozzle. Since the configuration is such that the ink ejection pattern in the process of moving the nozzles is controlled, the ink dot distribution can be made uniform when printing on a three-dimensional printing target.

According to the second aspect of the present invention, the sub-scanning direction driving means moves the ejection head in the sub-scanning direction in accordance with the position of the ejection nozzle and in accordance with the inclination of the printing object in the sub-scanning direction. Since the stepwise movement interval at the time of the change is changed, the dot distribution state in the sub-scanning direction can be made uniform.

According to the third aspect of the present invention, the driving of the printing head in the sub-scanning direction is repeated in the sub-scanning direction because the driving of the ejection head in the sub-scanning direction is repeated until the moving amount of the ejection head coincides with the movement interval. The movement interval according to the inclination can be set.

According to the fourth aspect of the present invention, when the ejection nozzle is located at a position corresponding to a horizontal plane in the sub-scanning direction on the printing object, the movement interval is set to a predetermined interval, and When the printing target is located at a position corresponding to the inclined portion in the sub-scanning direction, the moving interval is set to an interval smaller than a predetermined interval according to the inclination angle of the inclined portion along the sub-scanning direction. The distribution state of the dots in the section can be made to match the distribution state of the dots in the horizontal plane.

According to the fifth aspect of the present invention, when the sub-scanning direction driving means drives the discharge head at a fine pitch, the moving amount of the discharge head in the sub-scanning direction matches the moving interval. When there is no driving, the main scanning direction driving unit is not driven, so that efficient printing can be performed.

According to the sixth aspect of the present invention, since the minute pitch is variable, it is possible to adjust the print quality.

According to the seventh aspect of the invention, the surface shape of the printing object is approximated by a plurality of polygons, and for each polygon, the movement of the ink in the process of moving the ejection nozzles in the main scanning direction and the sub-scanning direction, respectively. Since the ejection pattern is determined, it is possible to perform efficient printing on a three-dimensional printing target.

According to the eighth aspect of the present invention, since the discharge head having a plurality of discharge nozzles can be rotated, the interval between the plurality of discharge nozzles along the sub-scanning direction can be adjusted.

According to the ninth aspect of the present invention, when rotational driving is performed by the discharge head rotational driving means, the nozzle positional relationship in the sub-scanning direction does not shift between a plurality of color components. Printing with a plurality of color components at the scanning position can be performed relatively easily and efficiently.

According to the tenth aspect of the present invention, the discharge pattern of the ink from the discharge nozzles in the process of moving the discharge head in each of the main scanning direction and the sub-scanning direction according to the inclination of the printing object. Is determined, based on the ejection pattern, a continuous movement in the main scanning direction of the ejection head provided with the ejection nozzles with respect to the printing target, and a stepwise movement in the sub scanning direction orthogonal to the main scanning direction. The printing on the printing target is performed by controlling the ejection of the ink while controlling the ink ejection. Therefore, when printing on the three-dimensional printing target, the dot distribution of the ink can be made uniform.

According to the eleventh aspect, when the ejection head is moved in the sub-scanning direction in accordance with the inclination of the printing target in the sub-scanning direction corresponding to the position of the ejection nozzle at the time of printing. In order to control the stepwise movement of the ejection head in the sub-scanning direction based on the movement interval, the distribution of dots in the sub-scanning direction is uniform. Can be

According to the twelfth aspect of the present invention, since the driving of the discharge head in the sub-scanning direction is repeated at a fine pitch until the amount of movement of the ejection head coincides with the movement interval, the printing target in the sub-scanning direction is repetitively driven. The movement interval according to the inclination can be set.

According to the thirteenth aspect, when the ejection nozzle is located at a position corresponding to a horizontal plane in the sub-scanning direction on the printing object, the movement interval is set to a predetermined interval, and When the printing object is located at a position corresponding to the inclined portion in the sub-scanning direction, the interval in the inclined portion is set smaller than a predetermined interval according to the inclination angle of the inclined portion along the sub-scanning direction. Can be made to match the distribution state of the dots on the horizontal plane.

According to the fourteenth aspect of the present invention, when the ejection head is driven at a fine pitch and the amount of movement of the ejection head in the sub-scanning direction does not match the movement interval, the main scanning is performed. Since the ejection head is not continuously moved in the direction, efficient printing can be performed.

According to the fifteenth aspect, since the minute pitch is variable, it is possible to adjust the print quality.

According to the sixteenth aspect of the present invention, the surface shape of the printing object is approximated by a plurality of polygons, and the discharge pattern in the process of moving the discharge nozzle in each of the main scanning direction and the sub-scanning direction for each polygon. Is determined, efficient printing on a three-dimensional print target can be performed.

According to the seventeenth aspect of the present invention, a discharge head having a configuration in which a plurality of discharge nozzles are arranged in a plane defined by the main scanning direction and the sub-scanning direction is rotated in a plane based on a discharge pattern. Therefore, it is possible to adjust the interval between the plurality of ejection nozzles along the sub-scanning direction.

[Brief description of the drawings]

FIG. 1 is an external view illustrating a printing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a positional relationship between an ejection head and a printing target.

FIG. 3 is a diagram illustrating a principle for making a dot distribution uniform in a sub-scanning direction.

FIG. 4 is a diagram showing a specific driving method for realizing a movement interval in the sub-scanning direction.

FIG. 5 is a first diagram relating to the control of the ejection pattern in the main scanning direction.
It is a figure showing the method of.

FIG. 6 is a second diagram relating to the control of the ejection pattern in the main scanning direction.
It is a figure showing the method of.

FIG. 7 is a block diagram illustrating a control mechanism in the printing apparatus.

FIG. 8 is a flowchart illustrating an overall operation of the printing apparatus.

FIG. 9 is a diagram illustrating an example of a case where the shape of a printing target is approximated by a polygon plane.

FIG. 10 is a diagram illustrating an example of a case where the shape of a printing target is approximated by a polygon plane.

FIG. 11 is a diagram illustrating an example of a case where the shape of a print target is approximated by a polygon plane.

FIG. 12 is a diagram illustrating a rotation operation of the ejection head.

FIG. 13 is a diagram illustrating an example of a multi-nozzle configuration in an ejection head.

FIG. 14 is a diagram illustrating an example of a multi-nozzle configuration in an ejection head.

FIG. 15 is a diagram illustrating an example of a multi-nozzle configuration in an ejection head.

FIG. 16 is a diagram illustrating a conventional method for printing on a three-dimensional printing target.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 printing device 9 printing target 10 main scanning direction driving unit (main scanning direction driving unit) 20 sub-scanning direction driving unit (sub-scanning direction driving unit) 30 ejection head rotation driving unit (ejection head rotation driving unit) 43 control unit ( Control means) 50 ejection head 51 nozzle arrangement section 51y, 51m, 51c, 51k nozzle arrangement member 52 ejection nozzle 60 ejection nozzle drive section X main scanning direction Y sub scanning direction

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideaki Nakanishi 2-3-113 Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. (reference) 2C056 EA01 EA06 EB13 EB29 EC03 EC07 EC11 EC28 EC31 EC34 EC37 EC42 EC74 EC75 EC78 EC79 FA09 FA15 FB09 HA07 HA10 HA12 HA22 HA38 HA60

Claims (17)

[Claims] 1. A printing apparatus for performing printing on a three-dimensional printing object, comprising: an ejection head having an ejection nozzle for ejecting printing ink to the printing object; A main scanning direction driving unit that continuously moves the ejection head along a direction; a sub scanning direction driving unit that moves the ejection head stepwise along a sub scanning direction orthogonal to the main scanning direction; Control means for controlling a discharge pattern of ink in a process of moving the discharge nozzle in each of the main scanning direction and the sub-scanning direction according to an inclination of the printing target corresponding to a position of the discharge nozzle. A printing device characterized by the above-mentioned. 2. The printing apparatus according to claim 1, wherein the control unit corresponds to a position of the discharge nozzle, and drives the sub-scanning direction according to an inclination of the printing target in the sub-scanning direction. A printing unit for changing a stepwise movement interval when the means moves the ejection head in the sub-scanning direction. 3. The printing apparatus according to claim 2, wherein the sub-scanning direction driving unit repeats driving at a fine pitch until the moving amount of the ejection head in the sub-scanning direction matches the moving interval. A printing device characterized by performing. 4. The printing apparatus according to claim 2, wherein the control unit determines that the ejection nozzle is located at a position corresponding to a horizontal plane in the sub-scanning direction on the printing target. Sets the movement interval to a predetermined interval, and when the ejection nozzle is located at a position corresponding to the inclined portion in the sub-scanning direction on the printing target, sets the movement interval in the sub-scanning direction of the inclined portion. A printing apparatus, wherein the interval is set to be smaller than the predetermined interval according to an inclined angle along the printing apparatus. 5. The printing apparatus according to claim 3, wherein the control unit controls the ejection in the sub-scanning direction when the sub-scanning direction driving unit drives the ejection head at every minute pitch. A printing apparatus, wherein when the moving amount of the head does not match the moving interval, the main scanning direction driving unit is not driven. 6. The printing apparatus according to claim 3, wherein the minute pitch is variable. 7. The printing apparatus according to claim 1, wherein the control unit approximates a surface shape of the printing target with a plurality of polygons, and the main scanning direction is set for each polygon. A printing apparatus for determining a discharge pattern of ink in a process of moving the discharge nozzle in each of the sub-scanning directions. 8. The printing apparatus according to claim 1, further comprising: a discharge head rotation drive unit configured to rotate the discharge head in a plane defined by the main scanning direction and the sub-scanning direction. The printing apparatus, further comprising: a plurality of the ejection nozzles arranged in the plane in the ejection head. 9. The printing apparatus according to claim 8, wherein the ejection head includes, for each of a plurality of color components, a nozzle arrangement member in which a plurality of the ejection nozzles are arranged in the sub-scanning direction. The plurality of color components are connected to each other by a link mechanism so that the positional relationship of the nozzles in the sub-scanning direction does not shift between the plurality of color components when the discharge head is rotationally driven by the discharge head rotation driving unit. Wherein the plurality of nozzle arrangement members are connected to each other. 10. A printing method for performing printing on a three-dimensional printing object, wherein: (a) an ejection head is moved in each of a main scanning direction and a sub-scanning direction according to an inclination of the printing object. Determining the ejection pattern of the ink from the ejection nozzles in the process of moving the nozzle; and (b) the main scanning direction of the ejection head including the ejection nozzles with respect to the printing target based on the ejection pattern. A step of performing printing on the printing target by controlling the ejection of the ink while controlling the continuous movement to and the stepwise movement in the sub-scanning direction orthogonal to the main scanning direction, A printing method comprising: 11. The printing method according to claim 10, wherein the step (a) is performed in accordance with an inclination of the printing target in the sub-scanning direction corresponding to a position of the discharge nozzle when performing printing. Determining the ejection pattern so as to change a stepwise movement interval when the ejection head is moved in the sub-scanning direction; and the step (b) includes: A printing method comprising controlling stepwise movement in a scanning direction. 12. The printing method according to claim 11, wherein, in the step (b), the drive at a fine pitch is repeatedly performed until the movement amount of the ejection head in the sub-scanning direction matches the movement interval. A printing method, characterized in that: 13. The printing method according to claim 11, wherein in the step (a), the ejection nozzle is located at a position corresponding to a horizontal plane in the sub-scanning direction on the printing target. In the case, the movement interval is set to a predetermined interval, and when the ejection nozzle is located at a position corresponding to the inclined portion in the sub-scanning direction on the print target, the ejection nozzle is moved along the sub-scanning direction of the inclined portion. A printing method, wherein an interval smaller than the predetermined interval is set according to an inclination angle. 14. The printing method according to claim 12, wherein in the step (b), when the ejection head is driven at every minute pitch, a movement amount of the ejection head in the sub-scanning direction is reduced. The printing method according to claim 1, wherein the continuous movement of the ejection head in the main scanning direction is not performed when the movement interval does not match. 15. The printing method according to claim 12, wherein the minute pitch is variable. 16. The printing method according to claim 10, wherein in the step (a), the surface shape of the printing target is approximated by a plurality of polygons,
A printing method, wherein the ejection pattern in the process of moving the ejection nozzle in each of the main scanning direction and the sub-scanning direction is determined for each polygon. 17. The printing method according to claim 10, wherein in the step (b), the plurality of ejection nozzles are arranged in a plane defined by the main scanning direction and the sub scanning direction. A printing method comprising: rotating the ejection heads arranged in the plane on the basis of the ejection pattern.