JP2011110921A - Printing system, printing control program, and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the deterioration in an image quality by determining the irradiation condition of a temporary curing part on the basis of each color total ink ejection amount per unit area. <P>SOLUTION: The printing system includes a head 31 which ejects an electromagnetic wave curable ink in a plurality of colors towards a medium S, the temporary curing part 41 common to each color for temporarily curing the electromagnetic wave curable ink by illuminating the electromagnetic wave curable ink hit on the medium S with electromagnetic waves, and a controller which determines the irradiation condition of the temporary curing part 41 on the basis of each color total ink ejection amount per unit area obtained on the basis of printing data passed through halftone processing for every plurality of colors. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printing system, a printing control program, and a printing method.

  Based on print data that has been halftoned from the past, a head that discharges a plurality of colors of electromagnetic curable ink toward a medium and an electromagnetic curable ink that has landed on the medium are irradiated with electromagnetic waves to temporarily apply the electromagnetic curable ink. A printing technique having a temporary curing portion common to each color to be cured is known.

JP 2008-265285 A

However, the conventional technique has a problem that the image quality is lowered depending on the amount of the electromagnetic wave curable ink ejected to the medium because the irradiation amount of the electromagnetic wave is constant.
The present invention has been made in view of such a conventional problem, and an object thereof is to suppress deterioration in image quality.

The main invention for solving the above-mentioned problems is:
A head for ejecting a plurality of colors of electromagnetic curable ink toward a medium;
Irradiating the electromagnetic wave curable ink landed on the medium with electromagnetic waves to temporarily cure the electromagnetic wave curable ink;
A controller for determining the irradiation condition of the temporary curing portion based on a total ink discharge amount of each color per unit area obtained based on the print data subjected to halftone processing for each of the plurality of colors. Printing system.

  Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

2 is a block diagram illustrating a configuration of a printer. FIG. FIG. 2 is a schematic view around the head of the printer 2. 3A and 3B are cross-sectional views of the printer 2. 4 is an explanatory diagram of an example of a configuration of a head 31. FIG. FIG. 3 is a block configuration diagram illustrating functions of a computer 3 that is communicably connected to a printer 2. It is a figure which shows the program memorize | stored in the computer. FIG. 6 is a flowchart illustrating a printing process when printing is performed by the printing system 1. FIG. 3 is a diagram conceptually illustrating each cell partitioned in a grid pattern on a printing surface on a sheet. It is a graph which shows the relationship between the ink discharge amount per unit area, and the irradiation intensity | strength of an ultraviolet-ray. It is a table | surface which shows the relationship between the irradiation intensity | strength of the irradiation part 42, and an image quality.

  At least the following will become apparent from the description of the present specification and the accompanying drawings.

That is,
A head for ejecting a plurality of colors of electromagnetic curable ink toward a medium;
Irradiating the electromagnetic wave curable ink landed on the medium with electromagnetic waves to temporarily cure the electromagnetic wave curable ink;
A controller for determining the irradiation condition of the temporary curing portion based on a total ink discharge amount of each color per unit area obtained based on the print data subjected to halftone processing for each of the plurality of colors. Printing system.
According to such a printing system, it is possible to suppress deterioration in image quality.

Such a printing system,
By ejecting the electromagnetic curable inks of a plurality of colors while moving the head in the moving direction, dots are formed on the medium, and by irradiating the dots with electromagnetic waves while moving the temporary curing portion in the moving direction A pass that is a pre-curing process;
A transport operation for transporting the medium in a transport direction intersecting the moving direction;
Are repeated alternately,
The controller determines the irradiation condition of the temporary curing portion for each pass based on the total ink discharge amount of each color per unit area for each pass.
This is a printing system.
According to such a printing system, it is possible to determine an appropriate irradiation condition for each pass, and to further suppress deterioration in image quality.

Such a printing system,
The pre-curing part corresponds to a moving section in which the process of moving the pre-curing part is divided into a plurality of sections, and the irradiation condition is switched during the pass to irradiate,
The controller determines the irradiation condition of the temporary curing portion in each moving section for each pass based on the total ink discharge amount for each color per unit area in each moving section for each pass. This is a featured printing system.
According to such a printing system, it is possible to determine an appropriate irradiation condition in each moving section for each pass, and to further suppress deterioration in image quality.

Such a printing system,
The temporary curing unit is arranged in parallel in the transport direction, irradiates irradiation regions corresponding to each, and has a plurality of irradiation units that can be independently controlled,
The controller determines the irradiation condition of each irradiation unit in each irradiation region for each pass based on the total ink discharge amount for each color per unit area in each irradiation region for each pass. This is a featured printing system.
According to such a printing system, it is possible to determine an appropriate irradiation condition in each irradiation region for each pass, and to further suppress deterioration in image quality.

Such a printing system,
In the printing system, the length of the moving section is longer than a length obtained by a product of a speed at which the temporary curing unit moves and a time required for the temporary curing unit to switch the irradiation condition.
According to such a printing system, the irradiation condition of the temporary curing unit 41 can be switched according to the moving speed, so that the temporary curing process can be executed accurately.

Such a printing system,
A computer and a printing device capable of communicating with the computer;
The computer
The controller;
An interface that transmits halftone processing data for each of the different colors and the irradiation condition to the printing apparatus;
The printing apparatus includes:
The head;
Each of the temporary curing portions,
A printing system comprising: print data subjected to halftone processing for each different color; and an interface for receiving the irradiation condition from the computer.
According to such a printing system, it is possible to suppress deterioration in image quality.

Also, a head that discharges a plurality of colors of electromagnetic curable ink toward the medium;
Irradiating the electromagnetic wave curable ink landed on the medium with electromagnetic waves to temporarily cure the electromagnetic wave curable ink;
A printing control program for controlling a printing apparatus comprising:
On the computer,
A function of generating halftone processed print data for each of the plurality of colors;
A function for obtaining a total ink discharge amount of each color per unit area based on the halftone processed print data;
A function of determining the irradiation condition of the temporary curing portion based on the total ink discharge amount of each color per unit area;
Is a print control program characterized by realizing the above.
According to such a print control program, it is possible to suppress deterioration in image quality.

Generating halftone processed print data for each of a plurality of colors;
Obtaining a total ink discharge amount of each color per unit area based on the halftone processed print data;
Based on the total ink discharge amount of each color per unit area, irradiating an electromagnetic wave to determine the irradiation condition of a common pre-curing portion for each color for pre-curing the electromagnetic wave curable ink;
Discharging the plurality of colors of electromagnetic curable ink from a head toward a medium;
Irradiating the electromagnetic wave curable ink landed on the medium under the irradiation conditions;
It is a printing method characterized by having.
According to such a printing method, it is possible to suppress deterioration in image quality.

=== First Embodiment ===
<About printer configuration>
Hereinafter, the printing system 1 of the present embodiment will be described with reference to FIGS. 1, 2, 3 </ b> A, 3 </ b> B, and 4. The printing system 1 includes a printer 2 (corresponding to a “printing apparatus”) and a computer 3.

  FIG. 1 is a block diagram illustrating the configuration of the printer 2. FIG. 2 is a schematic view around the head of the printer 2. 3A and 3B are cross-sectional views of the printer 2. 3A corresponds to the AA cross section of FIG. 2, and FIG. 3B corresponds to the BB cross section of FIG.

  The printer 2 of the present embodiment discharges ultraviolet curable ink (corresponding to “electromagnetic wave curable ink”) that is cured by irradiation of ultraviolet rays as an example of a liquid toward a medium such as paper, cloth, or film sheet. Thus, the apparatus prints an image on a medium. The ultraviolet curable ink is an ink containing an ultraviolet curable resin, and is cured by a photopolymerization reaction occurring in the ultraviolet curable resin when irradiated with ultraviolet rays. Note that the printer 2 of the present embodiment prints an image using four-color ultraviolet curable inks of CMYK (cyan, magenta, yellow, and black).

  The printer 2 includes a transport unit 10, a carriage unit 20, a head unit 30, an irradiation unit 40, a detector group 50, and a control unit 60. The printer 2 that has received the print data from the computer 3 that is an external device controls each unit (conveyance unit 10, carriage unit 20, head unit 30, irradiation unit 40) by the control unit 60. The control unit 60 controls each unit based on the print data received from the computer 3 and prints an image on a medium. The situation in the printer 2 is monitored by the detector group 50, and the detector group 50 outputs the detection result to the control unit 60. The control unit 60 controls each unit based on the detection result output from the detector group 50.

  The transport unit 10 is for transporting the paper S (corresponding to “medium”) in a predetermined direction (referred to as “transport direction”). The transport unit 10 includes a paper feed roller 11, a transport motor (not shown), a transport roller 13, a platen 14, and a paper discharge roller 15. The paper feed roller 11 is a roller for feeding the paper S inserted into the paper insertion slot into the printer. The transport roller 13 is a roller that transports the paper S fed by the paper feed roller 11 to a printable area, and is driven by a transport motor. The platen 14 supports the paper S being printed. The paper discharge roller 15 is a roller for discharging the paper S to the outside of the printer, and is provided on the downstream side in the transport direction with respect to the printable area.

  The carriage unit 20 is for moving a later-described head 31 in a predetermined direction (corresponding to a “movement direction”) that intersects the transport direction. The carriage unit 20 includes a carriage 21 and a carriage motor (not shown). In addition, the carriage 21 detachably holds an ink cartridge that stores ultraviolet curable ink. The carriage 21 is reciprocated along the guide shaft 24 by a carriage motor while being supported by a guide shaft 24 that intersects a conveyance direction described later.

  The head unit 30 is for ejecting ultraviolet curable ink onto the paper S. The head unit 30 includes a head 31 having a plurality of nozzles. Since the head 31 is provided on the carriage 21, when the carriage 21 moves in the movement direction, the head 31 also moves in the movement direction. Then, when the head 31 moves in the movement direction, the ultraviolet curable ink is intermittently ejected toward the paper S, whereby a dot line (raster line) along the movement direction is formed on the paper S.

  The printer 2 performs bidirectional printing. Hereinafter, a path moving from one end side to the other end side in FIG. 2 is referred to as a forward path, and a path moving from the other end side to the one end side is referred to as a return path. In the present embodiment, the ultraviolet curable ink is ejected during each of the forward pass and the return pass.

  FIG. 4 is an explanatory diagram of an example of the configuration of the head 31. As shown in FIG. 4, a cyan ink nozzle row Nc, a magenta ink nozzle row Nm, a yellow ink nozzle row Ny, and a black ink nozzle group Nk are formed on the lower surface of the head 31. Each nozzle row includes a plurality of nozzles that are ejection openings for ejecting ultraviolet curable ink of each color.

  Each nozzle is provided with a piezo element (not shown) as a drive element for discharging ultraviolet curable ink from each nozzle. By driving this piezo element with a drive signal, droplet-like ultraviolet curable ink is ejected from each nozzle. The discharged ultraviolet curable ink lands on the paper S to form dots.

  The irradiation unit 40 irradiates ultraviolet rays toward the ultraviolet curable ink landed on the paper S. The dots formed on the paper S are cured by being irradiated with ultraviolet rays from the irradiation unit 40. The irradiation unit 40 of this embodiment includes provisional curing portions 41 a and 41 b and a main curing portion 43. The temporary curing portions 41 a and 41 b are provided on the carriage 21.

  The temporary curing portions 41 a and 41 b are provided on one end side and the other end side in the moving direction of the head 31 so as to sandwich the head 31. That is, the temporary curing portions 41a and 41b are provided at positions aligned with the head 31 in the moving direction. Further, the length of the temporary curing portions 41 a and 41 b in the transport direction is substantially the same as the length of the nozzle row of the head 31. Then, the temporary curing units 41a and 41b move together with the head 31, and irradiate the dots formed on the paper S with ultraviolet rays to temporarily cure the dots (temporary curing process). That is, when the head 31 and the temporary curing unit 41 move from one end to the other end (forward movement), the temporary curing unit 41a located on the downstream side in the traveling direction irradiates ultraviolet rays, and the head 31 and the temporary curing unit 41 are moved from the other end. When moving to one end (return trip), the temporary curing portion 41b located downstream in the traveling direction irradiates ultraviolet rays.

The temporary curing unit 41a includes a large number of light emitting diodes (LEDs) as light sources for ultraviolet irradiation. Each LED can easily change the irradiation intensity (mW / cm ² ) by controlling the magnitude of the input current.

  In the present embodiment, a group of a plurality of LEDs is collectively controlled as the irradiation unit 42. Specifically, as shown in FIG. 4, the LEDs of the temporary curing portion 41 a are grouped into five irradiation portions 42 a 1 to 42 a 5, and the LEDs of the temporary curing portion 41 b are five of the irradiation portions 42 b 1 to 42 b 5. Are grouped together. Each irradiation part 42a1-42a5, 42b1-42b5 is controllable independently, respectively, and each irradiates a corresponding irradiation area | region.

  The main curing unit 43 is provided downstream of the carriage 21 in the transport direction. That is, the main curing unit 43 is provided on the downstream side in the transport direction from the head 31 and the temporary curing units 41a and 41b. Further, the length of the main curing unit 43 in the moving direction is longer than the width of the sheet S so that the entire surface of the sheet S can be irradiated in the moving direction. Then, the main curing unit 43 irradiates the sheet S conveyed under the main curing unit 43 by the conveying operation with ultraviolet rays, and cures the dots of the ultraviolet curable ink landed on the sheet S. The main curing unit 43 of this embodiment includes a lamp (a metal halide lamp, a mercury lamp, or the like) as a light source for ultraviolet irradiation.

  The detector group 50 includes a linear encoder (not shown), a rotary encoder (not shown), a paper detection sensor 53, an optical sensor 54, and the like. The linear encoder detects the position of the carriage 21 in the moving direction. The rotary encoder detects the rotation amount of the transport roller 13. The paper detection sensor 53 detects the position of the leading edge of the paper S being fed. The optical sensor 54 detects the presence or absence of the paper S by a light emitting unit and a light receiving unit attached to the carriage 21. The optical sensor 54 can detect the width of the paper S by detecting the position of the edge of the paper S while being moved by the carriage 21. Further, the optical sensor 54 also has a leading end (an end on the downstream side in the transport direction, also referred to as an upper end) and a rear end (an end on the upstream side in the transport direction, also referred to as a lower end) of the paper S depending on the situation. It can be detected.

  The control unit 60 is a control unit for controlling the printer 2. The control unit 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 transmits and receives data between the computer 3 which is an external device and the printer 2. The CPU 62 is an arithmetic processing unit for controlling the entire printer 2. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and includes storage elements such as a RAM and an EEPROM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

  When printing, the control unit 60 forms dots on the paper S by ejecting UV curable inks of CMYK colors while moving the head 31 in the moving direction, and moving the temporary curing unit 41 in the moving direction. A pass, which is a process of temporary curing by irradiating the dots with ultraviolet rays, is performed. Further, the control unit 60 performs a transport operation for transporting the paper S in the transport direction that intersects the moving direction after each pass. That is, the control unit 60 repeatedly performs the pass and the transport operation alternately.

<Schematic configuration of computer>
FIG. 5 is a block configuration diagram illustrating functions of the computer 3 that is communicably connected to the printer 2. As shown in FIG. 5, the computer 3 includes a CPU (Central Processing Unit) 71, a memory 72, a storage unit 73, a recording medium reading unit 74, a communication interface 75, an input unit 76, an output unit 77, and the like.

  The CPU 71 reads a program such as a printer driver program stored in the storage unit 73 into the memory 72 and executes it. The memory 72 is, for example, a DRAM (Dynamic Random Access Memory). The storage unit 73 is, for example, a hard disk drive. The recording medium reading unit 74 is a drive device that reads a program and data recorded on a recording medium 78 such as a CD-ROM (Compact Disc Read Only Memory), and supplies the read program and data to the CPU 71. The communication interface 75 is a network connection device such as a NIC (Network Interface Card), for example, and is connected to the printer 2 via a connector (not shown) to perform communication. Accordingly, when the printer 2 receives print data from the computer 3 side, the printer 2 starts processing for printing based on the print data. Further, the computer 3 receives information on the ultraviolet curable ink of each cartridge from the printer 2 side via the communication interface 75. The input unit 76 is, for example, a keyboard or a mouse. The output unit 77 is, for example, a display.

  FIG. 6 is a diagram illustrating a program stored in a controller functionally provided in the computer 3. As shown in the figure, an application program 81 and a printer driver program 82 are installed in the controller, and the printer driver program 82 operates under a predetermined operating system (OS). When the printer driver program 82 is read into the memory 72 or the like and is in an activated state calculated by the CPU 71, a part for creating print data is functionally realized.

  The application program 81 here is, for example, a program for image processing or image display, which processes an image captured from a digital camera or the like, processes an image drawn by an operator, This is executed when the image is output to the printer driver program 82 after being displayed.

  The printer driver program 82 receives image data from the application program 81 based on a print command from the application program 81 and converts it into print data to be supplied to the printer 2. The printer driver program 82 includes a resolution conversion module 82a, a color conversion module 82b, a halftone module 82c, a rasterizer 82d, a color conversion lookup table, and an SMB table.

  The resolution conversion module 82a converts the resolution of the color image data formed by the application program 81 into the resolution for printing with the printer 2 (for example, when the printer 2 is 720 dpi × 720 dpi, the image data is 720 dpi × 720 dpi). The process of converting to the resolution of the above. The color conversion module 82b converts the RGB image data into multi-tone data of a plurality of ink colors that can be used by the printer 2 for each pixel while referring to the color conversion lookup table. For example, when the printer 2 has four colors of CMYK, the color-converted multi-gradation data becomes CMYK data represented by CMYK, for example, 256 gradations.

  The halftone module 82c is a part that performs processing for converting the above multi-gradation data (CMYK data) into print data of the number of gradations formed by the printer 2. For example, when the head 31 can sort the ink droplets according to the large, medium, and small ink droplets, a process of converting each pixel into large, medium, small, and none data is performed with reference to the SMB table. Here, the SMB table stores in advance the correspondence of how many large, medium, and small dots are generated with respect to the multi-level gradation value indicated by each pixel data for each color.

  In the halftone process, image data is formed by dispersing individual pixels (dots) by a method such as a dither method or an error diffusion method.

  The rasterizer 82d is a part that performs processing for rearranging the print data after the halftone processing in the order of data to be transferred to the printer 2. The print data after the rasterization process is transmitted to the printer 2 together with data indicating the transport direction feed amount.

<Print processing flow>
FIG. 7 is a flowchart showing a printing process executed by the controller when printing is performed by the printing system 1. Hereinafter, the printing process will be described with reference to FIG.

  First, prior to printing, the operator activates the application program 81 to display desired image data (S701).

  When the operator selects a predetermined print mode, for example, for performing high-definition printing, and then issues a print command, the printer driver program 82 is activated based on the print command. When the printer driver program 82 is activated, first, resolution conversion processing corresponding to printing by the printer 2 is executed on the image data by the resolution conversion module 82a (S702).

  The resolution-converted print data is then converted by the color conversion module 82b from RGB print data to CMYK print data, that is, multi-tone data of each color of cyan print data, magenta print data, yellow print data, and black print data. (S703).

  The print data subjected to the color conversion processing is further subjected to halftone processing by the halftone module 82c (S704). In other words, the multi-level gradation values indicated by the pixel data constituting the CMYK print data can be expressed by the printer 2 with reference to the SMB table in small levels (for example, large, medium, small, and none). Converted to a value.

  The computer 3 receives an input from the operator regarding the image quality level such as the photograph image quality (high image quality) and the character image quality (normal image quality). The computer 3 selects FOL (Full Over Lap) printing when accepting the selection of photo quality, and selects POL (Part-Line Over Lap) printing when accepting the selection of normal image quality. A method is selected (S705). The computer 3 acquires a rasterization method corresponding to the selected printing method from a rasterization method storage unit that stores various rasterization methods (S706).

  The halftone processed print data is subjected to processing (rasterization processing) by the rasterizer 82d for rearranging in order of data to be transferred to the printer 2 (S707). That is, the print data is rearranged in the order in which dots are formed on the paper S by discharging ultraviolet curable ink from the head.

  For each pass, the total ink discharge amount for each color in each irradiation area irradiated by each irradiation unit 42 per unit area (for example, per square inch) in each moving section is obtained (S708). In other words, the printing surface on the paper S is virtually divided into grids by dividing each irradiation area in the transport direction and by each movement section in the movement direction, and each cell for each pass. The total ink discharge amount of each color per unit area is obtained. FIG. 8 is a diagram conceptually showing each cell partitioned in a grid pattern on the printing surface on the paper S. FIG. As shown in the figure, the printing area to be printed on the paper S is divided into grid-like cells by dividing each printing unit 42 in the transport direction and by each moving section in the moving direction. . Based on the rasterized print data, the total ink discharge amount of each color per unit area in each cell partitioned in a grid is calculated for each pass.

The total ink discharge amount V (ng) for each color per unit area of each cell is such that the ink droplet amount for large dots is α (ng), the ink droplet amount for medium dots is β (ng), and the ink droplet amount for small dots is γ. If it is (ng), for example, it can be obtained by the following equation (1).
V = α · A + β · B + γ · C (1)
Here, A is the number of large dots per unit area, B is the number of medium dots per unit area, and C is the number of small dots per unit area. In addition, the ink discharge amount per unit area is controlled to be the maximum ink discharge amount V _max at the maximum. That is, the ink ejection amount per unit area in the case of a so-called solid printing is a maximum ink ejection amount V _max Then, based on each color total amount of ink discharged per unit area of each cell is calculated, for each cell Irradiation conditions are determined for each pass (S709).

  Here, the irradiation condition is an irradiation energy amount (mJ / cm 2) per unit area of the ultraviolet rays irradiated by the irradiation unit 42. This is determined by the product of the irradiation intensity (mW / cm 2) of the temporary curing portion 41 and the irradiation time (s) to each dot. Further, the irradiation time (s) to each dot is obtained by dividing the moving direction length (cm) of the region irradiated with ultraviolet rays on the paper S by the moving speed (cm / s) of the temporary curing portion 41.

  Note that the length of the moving section is longer than the length obtained by the product of the moving speed (cm / s) of the temporary curing portion 41 and the time (s) required for the temporary curing portion 41 to switch the irradiation conditions.

  FIG. 9 is a graph showing the relationship between the ink discharge amount per unit area and the irradiation intensity of ultraviolet rays. As shown in the figure, the control unit 60 controls the temporary curing unit 41 so that the amount of irradiation energy per unit area of ultraviolet light increases as the ink discharge amount per unit area decreases.

  The rasterized print data and irradiation conditions are transmitted to the printer 2 (S710). Then, the printer 2 prints an image on the paper S based on the received print data and irradiation conditions (S711).

<Effectiveness of this embodiment>
According to the present embodiment, it is possible to suppress deterioration in image quality by determining the irradiation condition of the temporary curing unit 41 based on the total ink discharge amount of each color per unit area.

  In general, ultraviolet curable inks cure by radical polymerization when irradiated with ultraviolet rays, but when oxygen adheres to ultraviolet curable inks, oxygen functions as an inhibitor and reduces the rate of chain polymerization. It has been known. Therefore, at locations where the amount of ink discharged per unit area is small, the ink layer is easily affected by oxygen from the upper layer, so that oxygen inhibition tends to occur and the ink layer tends to be hard to cure. In order to cope with such a property of the ultraviolet curable ink, the control unit 60 performs control to increase the irradiation energy amount per unit area as the total ink discharge amount of each color per unit area is smaller. As a result, an appropriate amount of ultraviolet rays can be applied to the ultraviolet curable ink that has landed on the paper S, and optimal curing can be performed. Moreover, since it is not necessary to irradiate ultraviolet rays more than the amount necessary for temporary curing, it contributes to energy saving.

  FIG. 10 is a table showing the relationship between the irradiation energy amount of the precured portion 41, surface tackiness, and bleeding. As shown in the figure, when the amount of ink discharged per unit area is small, the surface tackiness and bleed state are not good if the amount of irradiation energy is small. However, when the ink discharge amount per unit area is small, the irradiation energy amount is increased. When the ink discharge amount per unit area is small, the irradiation energy amount is increased, and when the ink discharge amount per unit area is large. If the amount of irradiation energy is controlled in accordance with the amount of ink discharged per unit area, such as reducing the amount of irradiation energy, surface tackiness and bleeding are improved.

  In addition, by performing optimal curing, if the surface tackiness is good, the handleability of the product (printed material) after printing is improved. That is, since the print image is appropriately cured, the ultraviolet curable ink that has landed on the paper S does not adhere to another location.

  Furthermore, by performing optimal curing, the gloss of the entire image becomes uniform, and the appearance of the entire image is improved.

  In addition, according to the present embodiment, the total ink discharge amount of each color per unit area in each movement section, which is each irradiation region irradiated by each irradiation unit 42 for each pass, is obtained, and the calculated unit area of each cell Since the irradiation condition for each cell is determined for each pass on the basis of the total ink discharge amount for each color, finer and optimal curing can be performed for each portion of the paper S.

  In addition, since the length of the moving section is longer than the length obtained by the product of the moving speed (cm / s) of the temporary curing portion 41 and the time (s) required for the temporary curing portion 41 to switch the irradiation condition, Switching of the irradiation conditions of the temporary curing unit 41 can follow the moving speed, and therefore the temporary curing process can be executed accurately. Thereby, it is possible to further suppress the deterioration of the image quality.

=== Other Embodiments ===
Although the first embodiment is mainly described with respect to a printing apparatus, disclosure of a printing method and the like is also included. The first embodiment is intended to facilitate understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About moving mechanism>
In the first embodiment, the head and the paper S are relatively moved by transporting the paper S using the carriage unit 20, but the moving mechanism is not limited to this. For example, the head unit 40 and the sheet S may be moved relative to each other by moving the head 31, the temporary curing unit 41, and the main curing unit 43 while the sheet S is in a predetermined position.

<About the head>
In the first embodiment, the head 31 that ejects ink using a piezoelectric element is used. However, the method for discharging the fluid is not limited to this. For example, other methods such as a method of generating bubbles in the nozzle by heat may be used.

<About UV curable ink, temporary curing portion and main curing portion>
In the first embodiment, ultraviolet curable ink is exemplified as the ink ejected from the head unit 40, and ultraviolet rays are exemplified as the electromagnetic wave irradiated by the temporary curing unit 41 and the main curing unit 43. However, the present invention is not limited thereto. It is not something. For example, electromagnetic waves such as an electron beam, X-rays, and visible light may be included in the electromagnetic waves irradiated by the temporary curing unit 41. Further, the main curing unit 43 may irradiate electromagnetic waves such as electron beams, X-rays, and visible light. Further, the ink may be ink that is cured by electromagnetic waves corresponding to these.

<Regarding the control flow of the temporary curing unit 41>
In the first embodiment, the total ink discharge amount of each color per unit area in each movement section in each irradiation area irradiated by each irradiation unit 42 for each pass is obtained, and the calculated per unit area of each cell is calculated. Based on the total ink discharge amount for each color, the irradiation condition for each cell is determined for each pass.

  However, the irradiation condition for each cell is not determined, and the irradiation condition may be determined for each pass. According to such an embodiment, the amount of processing information in the computer 3 can be reduced.

  Also, for each pass, the total ink discharge amount for each color per unit area in each movement section is obtained, and the irradiation condition for each movement section is passed based on the calculated total ink discharge amount for each color per unit area of each movement section. It may be determined every time.

  Further, each color total ink discharge amount per unit area in each irradiation region irradiated by each irradiation unit 42 for each pass is obtained, and based on each color total ink discharge amount per unit area in each calculated irradiation region, The irradiation condition in the irradiation region may be determined for each pass.

<About the controller>
In the first embodiment, the controller that executes the processes illustrated in S701 to S709 in FIG. 7 is provided in the computer 3. However, the controller may be provided in the printer 2, and in this case, the printer 2 The provided controller may execute each process of S701 to S709.

  Further, the controller may be provided in each of the printer 2 and the computer 3, and in this case, the controller provided in the printer 2 and the computer 3 may execute the processes of S701 to S709 in a shared manner.

<Print processing flow>
In the print processing flow shown in FIG. 7, the processing in S710 may be executed before each processing in S701 to S709.

DESCRIPTION OF SYMBOLS 1 Printing system 2 Printer 3 Computer 10 Conveyance unit 11 Feed roller 13 Conveyance roller 14 Platen 15 Discharge roller 20 Carriage unit 21 Carriage 24 Guide shaft 30 Head unit 31 Head 40 Irradiation unit 41 Temporary curing part 42 Irradiation part 43 Main curing part 50 detector group 53 paper detection sensor 54 optical sensor 60 control unit 61 interface unit 62 CPU
63 Memory 64 Unit control circuit 71 CPU
72 Memory 73 Storage unit 74 Recording medium reading unit 75 Communication interface 76 Input unit 77 Output unit 78 Recording medium 81 Application program 82 Printer driver program 82a Module 82b Module 82c Halftone module 82d Rasterizer

Claims (8)

A head for ejecting a plurality of colors of electromagnetic curable ink toward a medium;
Irradiating the electromagnetic wave curable ink landed on the medium with electromagnetic waves to temporarily cure the electromagnetic wave curable ink;
A controller for determining the irradiation condition of the temporary curing portion based on a total ink discharge amount of each color per unit area obtained based on the print data subjected to halftone processing for each of the plurality of colors. Printing system to do. The printing system according to claim 1,
By ejecting the electromagnetic curable inks of a plurality of colors while moving the head in the moving direction, dots are formed on the medium, and by irradiating the dots with electromagnetic waves while moving the temporary curing portion in the moving direction A pass that is a pre-curing process;
A transport operation for transporting the medium in a transport direction intersecting the moving direction;
Are repeated alternately,
The controller determines the irradiation condition of the temporary curing portion for each pass based on the total ink discharge amount of each color per unit area for each pass.
A printing system characterized by that. The printing system according to claim 2,
The pre-curing part corresponds to a moving section in which the process of moving the pre-curing part is divided into a plurality of sections, and the irradiation condition is switched during the pass to irradiate,
The controller determines the irradiation condition of the temporary curing portion in each moving section for each pass based on the total ink discharge amount for each color per unit area in each moving section for each pass. Characteristic printing system. The printing system according to claim 2 or 3,
The temporary curing unit is arranged in parallel in the transport direction, irradiates irradiation regions corresponding to each, and has a plurality of irradiation units that can be independently controlled,
The controller determines the irradiation condition of each irradiation unit in each irradiation region for each pass based on the total ink discharge amount for each color per unit area in each irradiation region for each pass. Characteristic printing system. The printing system according to claim 3,
The length of the moving section is longer than the length obtained by the product of the speed at which the temporary curing portion moves and the time required for the temporary curing portion to switch the irradiation conditions. A printing system according to any one of claims 1 to 5,
A computer and a printing device capable of communicating with the computer;
The computer
The controller;
An interface that transmits halftone processing data for each of the different colors and the irradiation condition to the printing apparatus;
The printing apparatus includes:
The head;
Each of the temporary curing portions,
A printing system comprising: print data subjected to halftone processing for each different color and an interface for receiving the irradiation condition from the computer. A head for ejecting a plurality of colors of electromagnetic curable ink toward a medium;
Irradiating the electromagnetic wave curable ink landed on the medium with electromagnetic waves to temporarily cure the electromagnetic wave curable ink;
A printing control program for controlling a printing apparatus comprising:
On the computer,
A function of generating halftone processed print data for each of the plurality of colors;
A function for obtaining a total ink discharge amount of each color per unit area based on the halftone processed print data;
A function of determining the irradiation condition of the temporary curing portion based on the total ink discharge amount of each color per unit area;
A print control program characterized by realizing the above. A printing method for printing by a printing apparatus,
Generating halftone processed print data for each of multiple colors;
Obtaining a total ink discharge amount of each color per unit area based on the halftone processed print data;
Based on the total ink discharge amount of each color per unit area, irradiating an electromagnetic wave to determine the irradiation condition of a common pre-curing portion for each color for pre-curing the electromagnetic wave curable ink;
Discharging the plurality of colors of electromagnetic curable ink from a head toward a medium;
Irradiating the electromagnetic wave curable ink landed on the medium under the irradiation conditions;
A printing method characterized by comprising:

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