1. Field of the Invention
The present invention relates to an ink jet printing apparatus, an ink jet printing method, and a data generating apparatus by which a printing head capable of ejecting an ink and a processing liquid can scan a predetermined area of a printing medium a plurality of times to form an image by ejecting the ink onto the printing medium and to cover the formed image with the processing liquid.
2. Description of the Related Art
In recent years, ink jet printing apparatus has been widely used to provide printed images having higher definition, for public display applications and commercial display applications such as photographs, posters, and graphic prints. In the case of images formed for public display applications and commercial display applications, a requirement for high definition as well as a requirement for improving the image quality (e.g., uniform glossiness, bronze characteristic) and a requirement for improving the image toughness providing the strength and the long-term storage stability of the image. The bronze characteristic refers to a degree at which a color different from that of illumination light is reflected due to the bronze phenomenon when illumination light has mirror reflection (specular reflection) at an image surface. The bronze characteristic is known as being remarkable in a cyan ink in particular.
Ink coloring used in an ink jet printing apparatus is mainly classified as either a dye-base ink or a pigment-base ink. Dye ink includes coloring dye dissolved in water or alcohol medium in a molecular state and thus has a characteristic that dye ink is more transparent than pigment ink and provides superior color production. However, dye ink is disadvantageous in that early discoloring is caused due to ultraviolet light or an active gas in the atmosphere. On the other hand, pigment ink has a superior discoloring resistance in its long-term storage. In recent years, advanced manufacturing techniques have allowed pigment ink to establish both long-term storage stability (unique to pigment ink) and superior color production equal to that of dye ink. Thus, more ink jet printing apparatuses use pigment ink mainly for demanding commercial printing applications such as photographs and posters where a printed image must be stored for a long term.
However, an application using pigment as described above in particular still has the conventional image quality-related problems such as where the glossiness of images tends to be unequal and where the bronze phenomenon occurs as typical in pigment cyan ink. Another problem is that an increased number of display applications such as posters show a weaker image toughness and a poorer long-term storage stability compared to an offset-printed image, for example.
The following section will exemplarily describe the problem of abrasion resistance among the image toughness-related problems. The main problem is that an image printed on a glossy paper using pigment ink is easily damaged, even in general handling operation such as the subsequent handling and display.
A printing medium used for an ink jet printing apparatus is structured so that the surface of a base member (not shown) such as a paper or a film has thereon an ink absorbing layer 24 for the purpose of absorbing an ink. In order to reduce the oozing of the ink for example, the ink absorbing layer 24 includes a great amount of inorganic fine particles (of silica or alumina, for example) that are highly-absorptive to ink solvent. A printing medium used for the printing of a photograph such as glossy paper must have a flat and smooth surface, and thus generally uses inorganic particles having a dimension of the order of less than a micrometer. Thus, the gap between inorganic fine particles formed in the ink absorbing layer 24 is proportional to the particles diameter and thus is formed by fine pores having a dimension of the order of less than a micrometer.
On the other hand, coloring pigment particles having a dimension of about 100 nanometers are dispersed in pigment ink. This prevents the coloring pigment particles from entering the ink absorbing layer 24, when the coloring pigment particles have a diameter larger than that of the fine pores of the ink absorbing layer 24. In this case, the coloring pigment particles remain on the surface of the ink absorbing layer 24 as if they are blocked by a filter. In the case of a printing medium such as glossy paper, the coloring pigment particles generally have a diameter larger than that of the fine pores of the ink absorbing layer 24. Thus, a pigment ink layer 25 is formed on the surface of the ink absorbing layer 24.
Due to the pigment ink layer 25 formed on the surface of the ink absorbing layer 24 as described above, the image surface is easily damaged when an external force is applied to the pigment ink layer 25. In some cases, the pigment ink layer 25 (image) may be peeled due to an external force. For this reason, images formed using pigment ink have frequently been considered to have abrasion resistance-related problems.
Japanese Patent Laid-Open No. 2000-153677 discloses a laminate film method to protect an image formed by a pigment ink by covering the printed face of the image by a cover film. Japanese Patent Laid-Open No. 2005-81754 discloses a liquid laminate method to cover the printed face of the image using transparent resin liquid. Japanese Patent Laid-Open No. 2003-170650 discloses a post-processing method to mix thermoplastic resin particles in the ink absorbing layer of a printing medium for pigment ink to subsequently heat the printing medium to adhere a pigment ink layer to the ink absorbing layer.
In the case of the laminate film method, the abrasion resistance-related problem can be solved by covering the image surface with a resin film having a high film strength. However, the image surface covered by the film deteriorates the original texture of the printing medium such as paper. The laminate processing also increases cost, because another apparatus different from a printing apparatus is required.
The liquid laminate method can carry out, just after the printing of the image, the liquid laminate processing in the same printing apparatus. However, in order to obtain a sufficient effect on the abrasion resistance, a film thickness of a few microns must be formed. As in the laminate film method, the original texture of the printing medium therefore deteriorates. As disclosed in Japanese Patent Laid-Open No. 2005-81754, a further higher abrasion resistance is practically required when a thin film having a thickness equal to or lower than 1 micron is formed.
In the case of the post-processing method, the types of printing media for which an improved abrasion resistance can be expected are limited, and a heating processing step is required, causing the apparatus to have a larger size.
The problem of the abrasion resistance as described above can be very effectively solved by forming a transparent layer on the top layer of the pigment ink layer 25 on glossy paper to reduce the dynamic friction coefficient of the image surface. In recent years a configuration has been suggested for an ink jet printing apparatus to use a glossy paper including a transparent layer formed by a processing liquid including resin having an abrasion resistance function to print an image.
Japanese Patent Laid-Open No. H8-216432 discloses a general method to apply the processing liquid as described above. In the general method, in order to improve the water resistance of an image formed by an anionic dye ink, a processing liquid including cationic substance is applied after the application of the anionic dye ink. This method uses a multi-path printing apparatus to apply the ink to a printing medium through a plurality of scannings to print an image. At the final printing in the plurality of printing scannings (final printing scanning), the processing liquid is ejected to a position at which the ink was ejected, based on the ejection data for the processing liquid.
Covering the outermost surface of a printed ink image on a printing medium with a transparent layer is very effective to improve an image performance such as abrasion resistance. However, in order to apply the processing liquid to the entire surface of an image printed by pigment inks of a plurality of colors, a relatively large amount of processing liquid is required as compared to the amount of each color of the pigment ink. This has caused problems such as requiring a large size ink tank for the processing liquid and an increased running cost due to an increased consumption of the processing liquid, for example.
When the processing liquid is applied only in the final printing scan as disclosed in Japanese Patent Laid-Open No. H8-216432, the processing liquid is applied through a single scanning. This creates a case where the processing liquid may be applied in an amount exceeding the limited total amount of the liquid that can be absorbed by the printing medium at one time. In this case, the excessive liquid may cause problems in the image performance, such as a flooded ink phenomenon, bleeding, beading, defective drying, and a interference pattern phenomenon due to the transparent layer finished to have a mirror surface. When the multi-path printing apparatus is structured so that the processing liquid is ejected through ejection openings of a printing head only in the final printing scan, ejection openings for ejecting the processing liquid are concentrated within a specific area, thus causing a risk of a lack of durability of the printing head. When a printing head for ejecting ink is used as the printing head for ejecting the processing liquid, only a part of a plurality of ejection openings existing in the printing head for ejecting the processing liquid is used to eject the processing liquid and the other ejection openings are not used, wasting ejection openings.
The present invention provides an ink jet printing apparatus, an ink jet printing method, and a data generating apparatus by which a processing liquid can be ejected at an appropriate timing to improve an image performance such as abrasion resistance and to provide the printing head with a longer life.
The present invention in its first aspect provides an ink jet printing apparatus as specified in claims 1 to 13.
The present invention in its second aspect provides an ink jet printing method as specified in claim 14.
The present invention in its third aspect provides a data generating apparatus as specified in claim 15.
According to the present invention, a processing liquid is ejected by a plurality of scannings of a printing head to a predetermined region already subjected to an image formation by an ink. Thus, ejection of the processing liquid can be carried out during two or more scannings. As a result, drying of the processing liquid ejected to the printing medium can be promoted while improving the image performance of the image (e.g., abrasion resistance) to prevent flooded ink, thus achieving the printing of a high-quality image. Furthermore, ejection timings of the processing liquid carried out at two or more scannings can expand an area of the printing head used to eject the processing liquid, thus improving the durability of the printing head.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
In this specification, the term “processing liquid” means a liquid that is put into contact with an ink to improve the image performance, such as the image toughness or image quality. The expression “improve the image performance” as used herein means to improve at least one of the abrasion resistance, the weather resistance, the water resistance, and the alkali resistance to improve the toughness of an image formed by the ink. On the other hand, the expression “to improve the image quality” means to improve at least one of the glossiness, the haze characteristic, and the bronze characteristic to improve the optical quality of an image formed by the ink. In this embodiment, a processing liquid that improves the abrasion resistance will be described as an example.
The following section will describe preferred embodiments of the present invention with reference to the drawings.
A cap unit 20 includes five caps 20K, 20C, 20M, 20Y and 20H for capping ink ejection faces of the respective printing heads. When a printing operation is not performed, the printing head 22 and the ink tank 21 are returned to a home position where the cap 20 is provided and wait until a predetermined time passes. When the predetermined time has passed, the printing head 22 is capped in order to prevent the ink ejection face of the printing head 22 (face including the ejection openings) from drying.
It is noted that, when each of these printing head or the ink tanks is individually described, the reference numeral given to the component is used. However, when these components are described collectively, the printing head is denoted with a generic reference numeral 22, the ink tank is denoted with a generic reference numeral 21, and the cap is denoted with a generic reference numeral 20.
In this example, the printing heads and the ink tanks constitute, in an integral or separate manner, a head cartridge. The head cartridge is detachably mounted on a carriage (not shown). The printing heads and the ink tanks also may be separately provided on the carriage without constituting the head cartridge.
The carriage is guided so as to be movable along the main scanning direction shown by the arrow X and caused by a carriage motor 2 to reciprocate via a belt 4 in the main scanning direction. The printing medium 1 is transported by a transportation roller in the sub-scanning direction (direction shown by the arrow Y) crossing (in this example, orthogonal to) the main scanning direction.
Next, compositions of the pigment ink and the processing liquid used in this embodiment will be described.
First, an aqueous solution of styrene/butylacrylate/acrylic acid copolymer ((copolymer ratio (weight ratio)=30/40/30), acid value of 202, weight-average molecular weight of 6500, and solid content of 10%) was neutralized by potassium hydroxide. The above polymer aqueous solution of 30 parts, pigment [C.I. pigment yellow 74 (product name: Hansa Brilliant Yellow 5GX (made by Clariant Co.))] of 10 parts, and ion-exchanged water of 60 parts were mixed and were mechanically agitated. Next, the above material was placed in a batch-type vertical sand mill (made by Aimex Co.) to fill zirconia beads having a diameter of 0.3 mm of 150 parts to the sand mill. Then, the material was subjected to a dispersion processing for 12 hours while being cooled by water. Then, this dispersion liquid was placed in a centrifuge separator to remove large particles. Then, the final prepared matter of yellow pigment dispersion was obtained that had a solid content of about 12.5% by weight, and an average particle diameter of 120 nm.
A yellow ink was prepared by mixing the above yellow pigment dispersion element with the following components to sufficiently agitate the resultant mixture to subject the mixture to pressurization and filtering by a micro filter having pore size of 1.0 μm (made by FUJI FILM Co.) to prepare the ink.
First, benzyl acrylate and methacrylic acid were used as raw material in the common procedure to prepare an AB-type block polymer having an acid value of 300 and a number average molecular weight of 2500. The AB-type block polymer was neutralized by potassium hydroxide aqueous solution and was diluted by ion-exchanged water to obtain homogeneous polymer aqueous solution of 50 mass %. The above polymer solution of 100 g and C.I. pigment red 122 of 100 g was mixed with ion-exchanged water of 300 g and the resultant mixture was mechanically agitated for 0.5 hours. Next, a microfluidizer was used to send the above mixture through an interaction chamber five times under a fluid pressure of about 70 MPa. Then, this dispersion liquid was subjected to a centrifugal separation processing to remove large particles. As a result, the final prepared matter of magenta dispersion liquid was obtained that had a pigment concentration of 10 mass % and a dispersant concentration of 5 mass %.
A magenta ink was prepared by mixing the above magenta dispersion liquid with the following components to sufficiently agitate the resultant mixture. Then, a micro filter (made by FUJI FILM Co.) having a pore size of 2.5 μm was used to subject the mixture to pressurization and filtering to prepare the ink having a pigment concentration of 4 mass % and a dispersant concentration of 2 mass %.
First, benzyl acrylate and methacrylic acid were used as raw material in the common procedure to prepare an AB-type block polymer having an acid value of 250 and a number average molecular weight of 3000. The AB-type block polymer was neutralized by potassium hydroxide aqueous solution and was diluted by ion-exchanged water to obtain homogeneous polymer aqueous solution of 50 mass %. Then, the above polymer solution of 180 g was mixed with C.I. pigment blue 15:3 of 100 g and ion-exchanged water of 220 g and the mixture was mechanically agitated for 0.5 hours. Next, a microfluidizer was used to send the above mixture through an interaction chamber five times under a fluid pressure of about 70 MPa. Then, this dispersion liquid was subjected to a centrifugal separation processing to remove large particles. As a result, the final prepared matter of cyan dispersion liquid was obtained that had a pigment concentration of 10 mass % and a dispersant concentration of 10 mass %.
A cyan ink was prepared by mixing the above cyan dispersion liquid with the following components to sufficiently agitate the resultant mixture. Then, a micro filter (made by FUJI FILM Co.) having a pore size of 2.5 μm was used to subject the mixture to pressurization and filtering to prepare the ink having a pigment concentration of 2 mass % and a dispersant concentration of 3 mass %.
Polymer aqueous solution used for the yellow ink of 100 g, carbon black of 100 g, and ion-exchanged water of 300 g were mixed and the mixture was mechanically agitated for 0.5 hours. Next, a microfluidizer was used to send this mixture through an interaction chamber 5 times under a fluid pressure of about 70 MPa. Then, this dispersion liquid was subjected to a centrifugal separation processing to remove large particles. As a result, the final prepared matter of black dispersion liquid was obtained that had a pigment concentration of 10 mass % and a dispersant concentration of 6 mass %.
A black ink was prepared by mixing the above black dispersion liquid with the following components to sufficiently agitate the resultant mixture. Then, a micro filter (made by FUJI FILM Co.) having a pore size of 2.5 μm was used to subject the mixture to pressurization and filtering to prepare the ink having a pigment concentration of 5 mass % and a dispersant concentration of 3 mass %.
The following components were mixed and the mixture was sufficiently agitated to prepare a processing liquid.
It is important that the processing liquid of this embodiment includes transparent resin material for the purpose of forming a transparent layer on the outermost surface of an image to improve the abrasion resistance. Such transparent resin material maybe transparent resin material copolymerized with a polydimethylsiloxane component. The use of this can provide a slippage property to efficiently reduce the dynamic friction coefficient. In this embodiment, transparent resin material copolymerized with a commercially-available polydimethylsiloxane component (the above-described acryl silicone copolymer: Simac US-450) is used. This processing liquid also maybe referred as coat ink, surface coat ink, clear ink, or reaction liquid.
Another transparent resin material providing the slippage property may be obtained by adding silicone oil to acryl-base resin. However, any resin material also may be used so long as the material can be used to form the transparent layer on the outermost surface of the pigment ink layer to reduce the dynamic friction coefficient.
Next, the printing operation in this embodiment will be described. In this example, the multi-path printing method is used by which five scannings are performed to form, for every one pixel (for every predetermined region), an image layer formed by an ink and a transparent layer formed by a processing liquid. The printing method performs four scannings to eject the respective color inks of cyan (C), magenta (M), yellow (Y), and black (K) to print an image in a predetermined region. At the four scannings and the subsequent fifth scanning, the processing liquid is ejected to form the transparent layer. In order to simplify the description of the printing operation, the following section will assume that ink used for the printing of the image is only cyan (C) ink and magenta (M) ink.
First, in the first scanning, based on the ejection data at the first scanning of the printing region 50-1, the ink is ejected through the ejection openings of the regions A of the printing heads 22C and 22M. Based on the ejection data for the processing liquid at the first scanning, the processing liquid is ejected through the ejection openings of the region a of the printing head 22H.
Next, the printing medium 1 is transported in the sub-scanning direction (direction shown by the arrow Y) in an amount ⅕ of the length of the printing head. In
Next, the printing medium 1 is transported in the sub-scanning direction in an amount ⅕ of the length of the printing head. In the subsequent third scanning, based on the ejection data at the third scanning of the printing region 50-1, the ink is ejected through the ejection openings of the region C of the printing heads 22C and 22M. Based on the ejection data for the processing liquid at the third scanning, the processing liquid is ejected through the ejection openings of the region c of the printing head 22H. In this third scanning, the second scanning to the printing region 50-2 and the first scanning to the printing region 50-3 are performed.
Next, the printing medium 1 is transported in the sub-scanning direction in an amount ⅕ of the length of the printing head. In the subsequent fourth scanning, based on the ejection data at the fourth scanning of the printing region 50-1, the ink is ejected through the ejection openings of the region D of the printing heads 22C and 22M. Based on the ejection data for the processing liquid at the fourth scanning, the processing liquid is ejected through the ejection openings of the region d of the printing head 22H. In this fourth scanning, the third scanning to printing region 50-2, the second scanning to the printing region 50-3, and the first scanning to the printing region 50-4 are performed.
Through the first to fourth scannings, the printing of the image on the printing region 50-1 by the cyan (C) ink and magenta (M) ink is completed.
Next, the printing medium 1 is transported in the sub-scanning direction in an amount ⅕ of the length of the printing head. In the subsequent fifth scanning, based on the ejection data for the processing liquid at the fifth scanning, the processing liquid is ejected through the ejection openings of the region e of the printing head 22H. As a result, the application of the processing liquid to the printing region 50-1 (i.e., the formation of the transparent layer 26) is completed. In this fifth scanning, the fourth scanning to the printing region 50-2, the third scanning to the printing region 50-3, the second scanning to the printing region 50-4, and the first scanning to the printing region 50-5 are performed.
Thereafter, similar scanning is repeated to consecutively complete the printing of the image to the printing regions 50-2 and 50-3, . . . and so on and the formation of the transparent layer 26.
When a pigment ink is used to form an image on glossy paper, as described above with reference to
The image output section 30 is controlled by a Micro Processor Unit (MPU) 302 based on a program stored in a ROM 304. A RAM 305 is used as an operation area or a temporary data storage area of the MPU 302. The MPU 302 controls, via an ASIC 303, a carriage driving system 308, a printing medium transportation driving system 309, a printing head recovery driving system 310, and a printing head driving system 311. The MPU 302 is structured so as to read data from and write data to a print buffer 306 via the ASIC 303.
The print buffer 306 temporarily stores image data converted to a format by which the data can be transferred to the printing head. A mask buffer 307 temporarily stores a predetermined mask pattern for optionally subjecting the data transferred from the print buffer 306 to the printing head to an AND processing. It is noted the plurality of sets of mask patterns for a plurality of multi-path printings having different numbers of paths are prepared in the ROM 304. In an actual printing, the applicable mask pattern is read from the ROM 304 and is stored in the mask buffer 307.
Next, a method of generating the ejection data for the processing liquid in this embodiment will be described with reference to
Specifically, first, RGB-type multi-valued image data is inputted through the image input section 28. Next, the RGB-type multi-valued image data is converted to multi-valued image data corresponding to the respective plurality of types of the inks (K, C, M, and Y) used for the printing of an image. Next, a binarization unit 31 develops, based on the pattern stored in the binarization pattern storage unit 32, multi-valued image data corresponding to the respective types of the inks to binary bit map data corresponding to the respective types of the inks. As a result, binary image data (ink ejection data) for applying the respective plurality of types of the pigment inks is generated.
The processing liquid ejection data for applying the processing liquid is generated based on the binary image data for the plurality of types of the pigment inks (ink ejection data) thus generated. This processing liquid ejection data is generated by a processing liquid pattern storage unit 35, a processing liquid data generation unit 33, and a logical sum computation processing unit (OR circuit) 34.
In this embodiment, the transparent layer 26 covering about 75% of the ink layer 25 formed by the pigment ink on a glossy paper (printing medium) as shown in
Next, a method for generating the processing liquid ejection data (processing liquid binary image data) will be described by exemplarily describing the method for the cyan (C) and magenta (M) inks among the pigment inks used in this embodiment.
As described above, the binarization unit 31 of
First, based on the binary bit map (C and M data) for the cyan (C) and magenta (M) inks, the processing liquid data generation unit 33 (see
In the manner as described above, for each one pixel (for a predetermined region), an order of the scanning, among the plurality of scannings for forming the image, at which the image formation is completed (image formation completion scanning) is detected. Specifically, based on the data of
Next, as shown in
Next, the logical sum computation processing unit (OR circuit) 34 calculates the logical sum of the pattern of
By generating the processing liquid ejection data for the respective scannings as described above, the entire area γ of the regions of the printing head 22H for ejecting the processing liquid can be used as described above to eject the processing liquid. It is noted that the method for generating the processing liquid ejection data based on the ejection data of the respective ink colors and the method for distributing the processing liquid ejection data to the respective scannings are not limited to the above-described methods.
The ejection data for the respective ink colors and the processing liquid ejection data are sent as print data to the image output section 30. Based on the print data, the image output section 30 forms the image and the transparent layer as described above.
As described above, in this embodiment, an order of the scanning (image formation completion scanning) at which the image formation is completed is detected, among a plurality of scannings for forming the image, for each one pixel (for each predetermined area). Specifically, the image formation completion scanning is detected for each one pixel and the processing liquid is ejected on and after the scanning next to the detected scanning. Thus, among the ink and the processing liquid ejected for each one pixel, the processing liquid is finally ejected to form the transparent layer so as to cover the dots of the respective colors of the inks for forming the image. The transparent layer can improve the abrasion resistance of the image. The processing liquid is ejected by ejection openings in the entire area of the printing head 21H. Thus, the nozzle can have an improved durability. When it is assumed that the processing liquid is ejected in the final scanning (the fifth scanning) among a plurality of scannings, the ejection openings in the area β of the printing head 21H in
As in the first embodiment, this embodiment is explained with the assumption that it uses the printing method to form the image through four scannings by the pigment inks of cyan (C) and magenta (M) only. The same parts as those of the above-described first embodiment will not be described further.
As describe above, the binarization unit 31 of
First, the data C and the data M are divided into pieces of data for the first scanning to the fourth scanning, respectively. The C and M data in the first, second, third, and fourth scannings of the printing region 50-1 corresponds to the regions A, B, C, and D of the printing heads 22C and 22M. As in the above-described embodiment, the data C is divided as shown in
The processing liquid ejection data in the fifth scanning is generated by a mask pattern of
Next, the logical sum computation processing unit (OR circuit) 34 calculates the logical sum of the pattern of
As shown in
As described above, in this embodiment, based on the mask pattern used for the image formation by the pigment ink for example, the processing liquid is ejected in two scannings—the final scanning and the previous scanning. Thus, the ejection pattern of the processing liquid in these scannings (i.e., the pattern by which dots formed by the processing liquid are arranged) can be previously determined. Consequently, the control for the printing can be easier both in the structure and in time.
In this embodiment, the range of ejection openings of a printing head for ejecting the processing liquid can be increased as in the above-described embodiment, thus providing the nozzle with an improved durability. Furthermore, by allocating the processing liquid ejection data to a plurality of scannings, the drying of dots of the processing liquid on the printing medium and an image can be speeded up to remedy problems in image performance such as the flooded ink phenomenon, and the interference pattern phenomenon.
In the above-described embodiments, the printing head is structured so that the ejection openings constituting a nozzle for ejecting the pigment ink and the ejection openings constituting a nozzle for ejecting the processing liquid are arranged in the main scanning direction. However, another printing head also can be used that is structured so that the ejection openings for ejecting the pigment ink and the ejection openings for ejecting the processing liquid are arranged in a dislocated manner in a direction crossing the main scanning direction (e.g., the sub-scanning direction). A larger number of n for ejecting the processing liquid also may be provided than the number of nozzles for ejecting the pigment ink and the former nozzles also may be arranged in a nozzle array longer than that in which the latter nozzles are arranged.
In the above-described first embodiment, the timing at which the processing liquid is ejected is divided to the final scanning (the fifth scanning) and the previous plurality of scannings (the first, second, third, and fourth scannings). In the second embodiment, the timing at which the processing liquid is ejected is divided to the final scanning (the fifth scanning) and the previous scanning (the fourth scanning). However, another configuration also can be structured so long as the completion of the formation of an image in a unit area (unit print area) such as each pixel is followed by the ejection, through a plurality of scannings, of the processing liquid to the unit area already subjected to the image formation. Thus, the number of divided timings for ejecting the processing liquid and the method therefor is not limited to the above-described embodiments. For example, the timing also may be divided into the final scanning (the fifth scanning) and the previous first and third scannings. It is not always required to apply the processing liquid to all unit areas after the image formation. With regard to a part of all unit areas, as in the above-described embodiments, the processing liquid mask pattern also can be used to thin out the processing liquid ejection data. With regard to a part of all unit areas, the processing liquid also may be ejected before the completion of the image formation. The reason is that the processing liquid ejected on the printing medium and on the formed image may expand to realize a coverage exceeding a coverage required to improve the image performance.
With regard to a pixel having no pigment ink ejection data (margin pixel), in the first embodiment, the processing liquid is ejected in the first scanning, and in the second embodiment, the processing liquid is ejected in the final scanning (the fifth scanning) and the previous scanning (the fourth scanning). However, with regards to a pixel having no pigment ink ejection data (margin pixel), the processing liquid also may be ejected only in the final scanning. In this case, the same effect is also obtained. Thus, with regards to a pixel having no pigment ink ejection data (margin pixel), the number at which the timing for ejecting the processing liquid is divided and the method thereof is not limited. Furthermore, the ejection of the processing liquid need not be performed for a pixel having no pigment ink ejection data (margin pixel).
In the above-described embodiments, for ejecting the processing liquid after the completion of the image formation by the pigment ink, the processing liquid is ejected after the scanning next to the scanning at which the image formation is completed. However, the processing liquid also may be ejected in the scanning at which the image formation is completed so long as the image formation by the pigment ink is completed. In this case, by using the printing head (
The present invention can be widely applied to various ink jet printing apparatuses in which a printing head that can eject an ink and a processing liquid is scanned over a predetermined area on a printing medium to form an image by the ink on the printing medium and to cover the formed image by the processing liquid. Thus, the configuration of the printing head and the number of printing heads are not limited to the above-described embodiments.
In the present invention, the processing liquid may be ejected in two or more scannings among a plurality of scannings to a predetermined area for which the image formation is completed. Thus, the processing liquid may be ejected in three or more scannings. When an image in a predetermined area is formed by the maximum n scannings of the printing head (n is an integer of two or more), the processing liquid also may be ejected in two or more scannings prior to the nth scanning of the printing head. Alternatively, the processing liquid also maybe ejected in two or more scannings including at least one scanning after the nth scanning of the printing head.
The processing liquid also may be ejected to a predetermined area in which no ink image is formed in at least one scannings among the plurality of scannings of the printing head. For example, the processing liquid can be ejected in the first scanning among a plurality of scannings of the printing head. When the image in a predetermined area is formed by the maximum n scannings of the printing head (n is an integer of two or more), the processing liquid also may be ejected in the first scanning after the nth scanning of the printing head.
The printing head also may eject one type of ink for forming an image or also may eject a plurality of different inks.
In the above-described embodiments, in addition to the pigment ink used for the image formation, the processing liquid for improving the image performance of the pigment ink (abrasion resistance in the above-described embodiments) is used. As described above, the processing liquid is basically used separately from the image formation. Thus, the processing liquid is preferably transparent and colorless. However, among the pigment inks used for image formation such as light cyan ink, light magenta ink, and light gray ink, a part or the entirety of light-color pigment ink also may be added with material for improving a function such as abrasion resistance so that the colored ink can function to achieve both of image formation and an improved function such as abrasion resistance. In this case, a processing liquid tank provided separately from the one for ink or an additional component such as a printing head (which corresponds to a component required by the addition of one color of ink) is not required. Thus, this can contribute a lot to miniaturization and price-reduction of the printing apparatus. Among the pigment inks used for image formation, a part or the entirety of deep-color pigment ink also may function as the processing liquid.
The predetermined area can be set as an area corresponding to a dot formed by the ink on the printing medium or also may be set as various areas. Although the processing liquid desirably includes a resin component for forming a transparent layer on the surface of the printing medium, various processing liquids also can be used.
The present invention can be used for various printing apparatuses using a printing medium such as a paper, cloth, nonwoven cloth, or an OHP film. Specifically, the present invention can be applied to a business machine such as a printer, a copier, or a facsimile.
Although the above-described embodiments has described a case where the image processor 29 for performing the characteristic processing of the present invention is provided in the ink jet printing apparatus, the image processor 29 is not required to be provided in the ink jet printing apparatus. For example, as shown in
The present invention is mainly characterized in the data processing carried out by the image processor 29. Thus, a data generating apparatus including the image processor 29 for carrying out the characteristic data processing of the present invention is also included in the scope of the present invention. In the present invention, when the image processor 29 is included in an ink jet printing apparatus, the ink jet printing apparatus functions as the data generating apparatus. In the present invention, when the image processor 29 is included in a host computer, the host computer functions as the data generating apparatus.
A computer program for enabling a computer to carry out the above-described characteristic data processing and a storage medium storing the program so that the program can be read by the computer are also included in the scope of the present invention.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2007-242664, filed Sep. 19, 2007, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
---|---|---|---|
2007-242664 | Sep 2007 | JP | national |
Number | Date | Country | |
---|---|---|---|
Parent | 12209869 | Sep 2008 | US |
Child | 13365651 | US |