JP6268796B2 - Image forming apparatus, image forming method, and program - Google Patents

Description

  The present invention relates to an inkjet image forming apparatus, an image forming method, and a program for forming an image by attaching ink to a recording medium based on image data.

  Data processing devices that process image data include personal computers and workstations. Then, image data composed of various objects (characters, paint, lines, and photographs) is formed by application software that operates on such a data processing apparatus.

  As an image forming apparatus that forms and outputs the image data as an image, there are a printer, a facsimile, a copying apparatus, and a multi-function machine thereof. Examples of the image forming method include an inkjet method and an electrophotographic method, and an image is formed on a recording medium such as paper using an image forming material such as a recording liquid (ink) or toner.

  In ink-jet image formation, ink may be smeared out from each other at the contours (color boundaries) of image components formed in different colors, and the contours may collapse. This is because the ink permeates each other because the ink at the color boundary is not completely dry.

  FIG. 13 is a diagram for explaining the blurring of the contour portion (hereinafter, color boundary blurring). Here, FIG. 13A shows a state where there is no color boundary blur, and FIG. 13B shows a state where there is a color boundary blur. As shown in FIG. 13A, even if an attempt is made to form a circular image component 802 of another color in a rectangular image component 801 of a certain color on the recording medium 800 as a target image, as shown in FIG. 13B. The image components 803 and 804 in which the color boundary blurring occurs are formed.

  There is known an image forming apparatus and an image forming method in which a blur around the image is prevented by applying a blurring agent around the image (Patent Document 1). However, this image forming apparatus and image forming method do not assume color boundary blurring and cannot prevent color boundary blurring.

  The present invention has been made to solve such problems, and its purpose is to suppress color boundary blurring when forming an image by attaching ink to a recording medium based on image data. And smoothing the contour.

  The present invention relates to a recording head for attaching ink dots to a recording medium, a processing agent attaching part for attaching a processing agent for controlling the spread of ink dots to the recording medium, and image data of a color boundary portion from image data. Color boundary detection means for detecting the color boundary image data, and based on the image data and the color boundary image data, ink dots are attached to the recording medium so that a gap is formed in the color boundary. Recording image data generating means for generating the recording image data, and processing agent attachment data generation for generating processing agent attachment data for attaching the treatment agent to the gap based on the color boundary image data And an image forming apparatus.

  According to the present invention, when an image is formed by attaching ink to a recording medium based on image data, it is possible to suppress color boundary blurring and to smooth the contour portion.

It is a figure for demonstrating the image forming method which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the image forming method which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the image forming method which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the image forming method which concerns on the 4th Embodiment of this invention. It is a figure for demonstrating the relationship between the structure of the processing agent used in the 2nd-4th embodiment of this invention, and the penetration amount of an ink. 1 is a diagram for describing a schematic configuration of an image forming apparatus according to a first embodiment of the present invention. It is a block diagram for demonstrating the structure of the control part of the image forming apparatus shown in FIG. FIG. 8 is a functional block diagram of a portion that executes an image forming method according to each embodiment of the present invention in the control unit shown in FIG. 7. It is a flowchart for demonstrating the processing agent implantation area | region setting process which concerns on embodiment of this invention. It is a flowchart for demonstrating the processing agent arrangement | positioning data generation process which concerns on embodiment of this invention. It is a figure for demonstrating the process which calculates the distance to the nearest colorant data in FIG. 10, and the process which moves an attention pixel. FIG. 6 is a diagram for describing a schematic configuration of a main part of an image forming apparatus according to a second embodiment of the present invention. It is a figure for demonstrating color boundary blurring.

Embodiments of the present invention will be described below with reference to the drawings.
<First Image Forming Method>
FIG. 1 is a diagram for explaining an image forming method according to the first embodiment of the present invention.

  As the image data 100, 25 pixel data consisting of 5 in the horizontal direction (row direction) and 5 in the vertical direction (column direction) (hereinafter, 5 rows × 5 columns) are shown. Of the 25 pixel data, the image data 101 composed of the pixel data of the left three columns forms an image of the first color on the recording medium. Further, the image data 102 composed of the two columns of pixel data on the right side forms an image of a second color different from the first color.

  When ink dots as a colorant are attached to a recording medium based on the image data 100, a first color image 201 formed based on the image data 101 and an image data 102 are formed. A color boundary blur 203 occurs between the image 202 of the second color.

  Therefore, in the image forming method according to the present embodiment, first, color boundary image data that is image data of a color boundary portion is detected from the image data 101 and the image data 102 (color boundary portion detection step).

  Next, based on the image data 101 and 102 and the color boundary image data, recording image data and processing agent adhesion data are generated. Here, the recording image data includes the ink dot 301 and the ink dot 301 so that a gap 303 is left at the color boundary between the first color ink dot 301 and the second color ink dot 302 on the recording medium. This is data for attaching 302. The processing agent attachment data is data for attaching the processing agent 304 for controlling the spread of ink dots to the gap 303.

  Next, based on the recording image data, ink dots 301 and 302 are attached to the recording medium (ink dot attaching step), and the processing agent 304 is attached to the gap 303 based on the processing agent attachment data (processing agent). Adhesion process).

  As a result, when the ink dots 301 and 302 penetrate into the gap 303, the spread of the ink dots is controlled, and images 401 and 402 having smooth contours without color boundary blurring are formed.

  Here, the gap is formed by removing (thinning out) the pixel data at the right end of the image data 101, but the gap is formed by removing the pixel data at the left end of the image data 102. Can also be formed. Further, the order of the ink dot attaching step and the treatment agent attaching step can be reversed. Moreover, the effect of reducing the color boundary blur can be changed by performing at least one of the ink dot attaching step and the treatment agent attaching step a plurality of times.

<Second Image Forming Method>
FIG. 2 is a diagram for explaining an image forming method according to the second embodiment of the present invention.

  As the image data 110, 25 pixel data of 5 rows × 5 columns are shown. Of the 25 pixel data, the image data 111 consisting of the entire left two columns and the odd-numbered pixel data from the top of the third column from the left forms an image of the first color on the recording medium. The image data 112 including even-numbered pixel data from the top of the third column from the left and pixel data of the right two columns forms an image of the second color.

  When ink dots as a colorant are attached to the recording medium based on the image data 110, the first color image 211 formed based on the image data 111 and the image data 112 are formed. A color boundary blur 213 is generated between the second color image 212 and the second color image 212.

  Therefore, in the image forming method according to the present embodiment, first, color boundary image data that is image data of a color boundary portion is detected from the image data 111 and the image data 112 (color boundary portion detection step).

  Next, based on the image data 111 and 112 and the color boundary image data, recording image data and processing agent adhesion data are generated. Here, the recording image data includes the ink dots 311 and the ink dots 311 and the color dots between the first color ink dots 311 and the second color ink dots 312 on the recording medium. This is data for attaching 312. The processing agent attachment data is data for attaching the processing agent 314 that controls the spread of ink dots to the gap 313.

  Next, ink dots 311 and 312 are attached to the recording medium based on the recording image data (ink dot attachment step), and the processing agent 314 is attached to the gap 313 based on the processing agent attachment data (processing agent). Adhesion process).

  In this treatment agent attaching step, a treatment agent 314 having a large amount of ink permeation (a degree of spreading) is attached to a dot far from the end of the ink dot 311 in the gap 313, and a dot close to the end of the ink dot 311 is attached to the dot. A treatment agent 315 having a small ink penetration amount is adhered.

  As a result, when the ink dots 311 and 312 penetrate into the gap 313, the spread of the dots is controlled, so that the images 411 and 412 having no color boundary blur are formed. Moreover, the precision which smoothes an outline improves by using the processing agent from which the osmosis | permeation amount differs according to the distance from a color boundary.

  Here, the gap is formed by removing (thinning out) the pixel data for one column of the image data 111, but the gap is formed by removing the pixel data of one column of the image data 112. You can also Further, the order of the ink dot attaching step and the treatment agent attaching step can be reversed.

<Third image forming method>
FIG. 3 is a diagram for explaining an image forming method according to the third embodiment of the present invention. Here, the image data to be processed is the same as in the second embodiment.

  When ink dots as a colorant are attached to the recording medium based on the image data 110, the first color image 211 formed based on the image data 111 and the image data 112 are formed. A color boundary blur 213 is generated between the second color image 212 and the second color image 212.

  Therefore, in the image forming method according to the present embodiment, first, color boundary image data that is image data of a color boundary portion is detected from the image data 111 and the image data 112 (color boundary portion detection step).

  Next, based on the image data 111 and 112 and the color boundary image data, recording image data and processing agent adhesion data are generated. Here, the recording image data has a gap 323 at the color boundary between the first color ink dots 321 and the second color ink dots 322 on the recording medium, and adheres to the gap 323. This is data for adjusting the area and position of the gap 323 by changing the number and position of ink dots to be changed. That is, the recording image data includes data for changing the area or position of the gap 323 by changing the size or position of the ink dots. The processing agent attachment data is data for attaching the processing agent 314 having a large ink penetration amount and the 315 having a small ink penetration amount to the gap 323.

  The ink dots circled in the ink dots 321 and 322 in FIG. 3 are ink dots for adjusting the area and position of the gap 323. In the present embodiment, the effect of preventing color boundary blurring can be changed by adjusting the area and position of the gap. In addition, as in the second embodiment, the accuracy of smoothing the contour is improved by using treatment agents having different penetration amounts according to the distance from the color boundary.

<Fourth Image Forming Method>
FIG. 4 is a diagram for explaining an image forming method according to the fourth embodiment of the present invention. Here, the image data to be processed is the same as in the second embodiment.

  When ink dots as a colorant are attached to the recording medium based on the image data 110, the first color image 211 formed based on the image data 111 and the image data 112 are formed. A color boundary blur 213 is generated between the second color image 212 and the second color image 212.

  Therefore, in the image forming method according to the present embodiment, first, color boundary image data that is image data of a color boundary portion is detected from the image data 111 and the image data 112 (color boundary portion detection step).

  Next, based on the image data 111 and 112 and the color boundary image data, recording image data and processing agent adhesion data are generated. Here, the recording image data includes the ink dots 311 and the ink dots 311 and the color dots between the first color ink dots 311 and the second color ink dots 312 on the recording medium. This is data for attaching 312. The processing agent attachment data is data for attaching the treatment agent 314 having a large ink penetration amount and the treatment agent 315 having a small ink penetration amount to the gap 313, and the size or position of the treatment agents 314 and 315. It is data including data indicating.

  Next, ink dots 311 and 312 are attached to the recording medium based on the recording image data (ink dot attaching step), and processing agents 314 and 315 are attached to the gap 313 based on the processing agent attachment data ( Treatment agent adhesion process).

  In this treatment agent attaching step, the sizes and positions of the dots of the treatment agents 314 and 315 are adjusted with respect to the second embodiment. In the figure, the dot size of the treatment agent 315 with a small amount of permeation is reduced, and the dots are arranged at substantially the center of the gap 313. Further, regarding the dots of the treatment agent 314 having a large penetration amount, the size is increased when it is far from the end of the ink dot 311, and the size is decreased when it is close.

  As described above, according to the present embodiment, the effect of preventing color boundary blurring can be changed by adjusting the type, dot size, and position of the processing agent.

<Fifth image forming method>
In this embodiment, the processing agent is given an overcoat function for protecting the image surface. Therefore, in the first to fourth embodiments, the ink dot attaching step and the processing agent attaching step are performed, and after the penetration of the ink dots is finished, the treating agent is attached to the entire surface of the image (overcoat forming step).

<Sixth image forming method>
Also in this embodiment, as in the fifth image forming method, the processing agent is provided with an overcoat function. Therefore, in the first to fourth embodiments, after the ink dot attaching step, the treating agent is attached to the entire surface of the ink dots simultaneously with the treating agent attaching step.

<Seventh image forming method>
An increasing number of products and technologies apply inkjet recording to non-penetrating media (for example, vinyl chloride sheets with release paper). In recording on non-penetrable media, the process of drying and fixing the ink is important.

  Therefore, in the present embodiment, in the first to fourth image forming methods, a non-penetrable medium is used as a recording medium, the recording medium is heated before ink dots are adhered, the ink is adhered, and the processing is performed. After the agent is attached, the ink dots and the treatment agent are dried.

<Relationship between treatment composition and ink penetration>
FIG. 5 is a diagram for explaining the relationship between the configuration of the treatment agent used in the second to fourth embodiments of the present invention and the ink penetration amount. In this figure, the horizontal axis shows the composition of the treatment agent, and the vertical axis shows the ink penetration amount.

  As shown in the figure, the amount of penetration can be controlled by combining a large / small penetration amount and a large / small dot size as the composition of the treatment agent. In addition, as will be described later with reference to FIG. 11, the pattern correction effect is checked in advance and tabulated, whereby a prescribed process can be performed when a predetermined pattern is input. The threshold value for evaluation may be set in advance by sensory evaluation or the like, or the setting may be given step by step.

<Example of treatment agent>
The treatment agent (overcoat solution) contains at least water, a water-soluble organic solvent, and resin fine particles. 50% by weight or more of the water-soluble organic solvent has a boiling point of 200 ° C. or less, thereby forming a particularly good boundary. It becomes possible to do. Further, the water-soluble organic solvent having a boiling point of 200 ° C. or less is preferably 70% by weight or more. If the ratio is less than 50% by weight, the drying property of the ink is inferior, and the ink cannot form a sufficient coating film and causes blocking.

Hereinafter, materials used for the overcoat liquid will be described.
(Resin fine particles)
The resin fine particles used in the overcoat liquid may contain any resin fine particles. Examples thereof include acrylic resin fine particles, polyolefin resin fine particles, vinyl acetate resin fine particles, vinyl chloride resin fine particles, fluororesin fine particles, polyether resin fine particles, polyester resin fine particles, and the like. The particle diameter of the resin fine particles is preferably 10 to 300 nm, and more preferably 30 to 150 nm.

(Water-soluble organic solvent)
As an example of the water-soluble organic solvent, any solvent that is compatible with water can be used. For example, ethylene glycol (bp 196 ° C.), propylene glycol (bp 188 ° C.), 1,2- Butanediol (bp194 ° C), 2,3-butanediol (bp183 ° C), 2-methyl-2,4-pentanediol (bp198 ° C), diethylene glycol (bp244 ° C), triethylene glycol (bp287 ° C), dipropylene glycol (bp230 ° C), 1,3-propanediol (bp214 ° C), 1,3-butanediol (bp203 ° C), 1,4-butanediol (bp230 ° C), 2,2-dimethyl-1,3-propanediol (bp 208 ° C), 2-methyl-1,3-propanediol (bp213 ° C), 1,2-pentanediol (bp206 ° C), 2,4-pentanediol (bp201 ° C), 1,5-pentanediol (bp242 ° C), 1,6-hexanediol (bp 250 ° C), 2-ethyl-1,3-hexanediol (bp243 ° C), 1,2-hexanediol (bp224 ° C), 2,5-hexane Diol compounds such as all (bp217 ℃) and the like.

Furthermore, as glycol ether compounds, dipropylene glycol monomethyl ether (bp 190 ° C.), propylene glycol n-butyl ether (bp 171 ° C.), propylene glycol-t-butyl ether (bp 153 ° C.), diethylene glycol methyl ether (bp 194 ° C.), ethylene glycol-n -Propyl ether (bp 150 ° C.), ethylene glycol-n-butyl ether (bp 171 ° C.) and the like.
These may be used alone or in combination of two or more.

  The water-soluble organic solvent used in the overcoat solution must be a water-soluble organic solvent having a boiling point of 200 ° C. or higher at 50% or more, and a solvent having a boiling point of 200 ° C. or lower is appropriately selected from the above solvents. It is possible.

(Overcoat liquid preparation example 1)
After mixing and stirring the materials of the following formulation, the mixture was filtered through a 0.2 μm polypropylene filter to prepare an overcoat solution.

《Overcoat liquid formulation》
・ Acrylic resin emulsion (Johncrill JDX-6500, manufactured by BASF Corp.) 15 parts ・ Surfactant CH ₃ (CH ₂ ) ₁₂ O (CH ₂ CH ₂ O) ₃ CH ₂ COOH 2 parts ・ Propylene glycol (bp188 ° C.) … 20 parts ・ Diethylene glycol-n-butyl ether (bp 230 ° C.)… 15 parts ・ Preservative and antifungal agent Proxel LV (manufactured by Avicia)… 0.1 part ・ Ion-exchanged water… 27.9 parts

(Overcoat liquid preparation example 2)
・ Acrylic resin emulsion (Johncrill JDX-6500, manufactured by BASF Corp.) 15 parts ・ Surfactant CH ₃ (CH ₂ ) ₁₂ O (CH ₂ CH ₂ O) ₃ CH ₂ COOH 2 parts ・ Propylene glycol (bp188 ° C.) … 17 parts ・ Diethylene glycol-n-butyl ether (bp 230 ° C.) 20 parts ・ Preservative and fungicide Proxel LV (manufactured by Avicia) 0.1 parts ・ Ion-exchanged water 25.9 parts

<Image Forming Apparatus According to First Embodiment>
FIG. 6 is a diagram for explaining a schematic configuration of the image forming apparatus according to the first embodiment of the present invention. This image forming apparatus can execute the image forming methods according to the first to sixth embodiments of the present invention.

  The image forming apparatus includes an image forming unit 2 and the like inside the apparatus main body 1, and includes a paper feed tray 4 on the lower side of the apparatus main body 1 on which a large number of sheets 3 as recording media can be stacked. . The paper 3 fed from the paper feed tray 4 is taken in, a desired image is formed by the image forming unit 2 while the paper 3 is being transported by the transport mechanism 5, and then the paper is mounted on the side of the apparatus main body 1. The paper 3 is discharged to the tray 6.

  In addition, the image forming apparatus includes a duplex unit 7 that can be attached to and detached from the apparatus main body 1. When performing double-sided printing, after the front side printing is finished, the paper 3 is taken into the double-sided unit 7 while being fed in the reverse direction by the carrying mechanism 5 and reversed, and the reverse side is sent to the carrying mechanism 5 again as a printable side, and the back side printing is finished. The sheet 3 is discharged to the rear discharge tray 6.

  Here, the image forming unit 2 slidably holds the carriage 13 on the guide shafts 11 and 12, and moves the carriage 13 in a direction orthogonal to the conveyance direction of the paper 3 (main scanning) by a main scanning motor (not shown). . The carriage 13 has a recording head 14 a that discharges droplets (ink droplets) and adheres to the paper 3, and has the same configuration as the recording head 14 a, and discharges the above-described processing agent to adhere to the paper 3. A processing agent discharge head 14b as a processing agent attaching portion is mounted. An ink cartridge 15a for supplying ink to the recording head 14a and a processing agent cartridge 15b for supplying processing agent to the processing agent discharge head 14b are detachably mounted.

  Here, the recording head 14a may be four independent inkjet heads that are droplet ejection heads that eject ink droplets of each color of yellow (Y), magenta (M), cyan (C), and black (Bk). Alternatively, it may be one or a plurality of heads having a plurality of nozzle rows that eject ink droplets of each color.

  The sheets 3 in the sheet feeding tray 4 are separated one by one by a sheet feeding roller (half moon roller) 21 and a separation pad (not shown), are fed into the apparatus main body 1, and are fed into the transport mechanism 5. The transport mechanism 5 guides the fed paper 3 upward along the guide surface 23a.

  Further, a conveyance guide unit 23 that guides the sheet 3 fed from the duplex unit 7 along the guide surface 23 b, a conveyance roller 24 that conveys the sheet 3, and a pressure roller 25 that presses the sheet 3 against the conveyance roller 24. A guide member 26 that guides the paper 3 toward the transport roller 24, a guide member 27 that guides the paper 3 returned during duplex printing to the duplex unit 7, and a pressing roller 28 that presses the paper 3 fed from the transport roller 24. Have.

  The transport mechanism 5 further includes a transport belt 33 that is stretched between the driving roller 31 and the driven roller 32 in order to transport the recording sheet 14a and the processing agent discharge head 14b while maintaining the flatness of the sheet 3. A charging roller 34 for charging the conveying belt 33, a guide roller 35 facing the charging roller 34, and a guide member (not shown) for guiding the conveying belt 33 at a portion facing the image forming unit 2 (plastic template). And a cleaning roller made of a porous material or the like, which is a cleaning means for removing the recording liquid (ink) adhering to the conveyance belt 33.

  Here, the conveyance belt 33 is an endless belt, and is configured to be wound around a driving roller 31 and a driven roller (tension roller) 32 and to circulate in the direction indicated by an arrow (paper conveyance direction). Has been.

  The charging roller 34 is disposed so as to come into contact with the surface layer of the transport belt 33 and to rotate following the rotation of the transport belt 33. A high voltage is applied to the charging roller 34 in a predetermined pattern from a high voltage circuit (high voltage power source) (not shown).

  Further, on the downstream side of the transport mechanism 5, a paper discharge roller 38 for sending the paper 3 on which an image is formed to the paper discharge tray 6 is provided.

  In the image forming apparatus configured as described above, the conveyance belt 33 rotates in the direction indicated by the arrow, and is positively charged by coming into contact with the charging roller 34 to which a high potential application voltage is applied. In this case, the charging roller 34 is charged at a predetermined charging pitch by switching the polarity at predetermined time intervals.

  Here, when the paper 3 is fed onto the conveying belt 33 charged at this high potential, the inside of the paper 3 is in a polarized state, and the electric charge having the opposite polarity to the electric charge on the conveying belt 33 is connected to the belt 33 of the paper 3. Dielectrically in contact with the surface. As a result, the electric charges on the belt 33 and the electric charges that are dielectric on the paper 3 to be conveyed are electrostatically attracted to each other, and the paper 3 is electrostatically attracted to the conveying belt 33. In this way, the sheet 3 strongly adsorbed to the transport belt 33 is calibrated for warpage and unevenness, and a highly flat surface is formed.

  Therefore, the paper 3 is moved by circling the conveyor belt 33, the recording head 14a is driven according to the recording image data while moving and scanning the carriage 13 in one or both directions, and droplets are ejected from the recording head 14a. (Ejection), ink droplets that are droplets are landed on the stopped paper 3 and ink dots are attached to record one line. Further, the processing agent discharge head 14 b is driven in accordance with the processing agent attachment data, and the processing agent is attached to the gap between the color boundaries of the ink dots on the paper 3.

  Next, after the sheet 3 is conveyed by a predetermined amount, the next line is recorded. When the recording end signal or the signal that the rear end of the paper 3 reaches the recording area is received, the recording operation is ended. In this way, the sheet 3 on which the image is recorded is discharged to the discharge tray 6 by the discharge roller 38. In addition, a hot air generating unit for applying hot air to the ink dots and the processing agent attached to the paper 3 and drying them may be provided above the paper discharge tray 6.

<Control unit of image forming apparatus>
FIG. 7 is a block diagram for explaining the configuration of the control unit of the image forming apparatus shown in FIG.
This control unit 500 includes a CPU 501 that controls the entire apparatus, a ROM 502 that stores programs executed by the CPU 501 and other fixed data, a RAM 503 that temporarily stores image data, and the like, while the apparatus is powered off. Also, a non-volatile memory (NVRAM) 504 for holding data and an ASIC 505 for performing image processing for performing various signal processing and rearrangement and other input / output signal processing for controlling the entire apparatus are provided.

  In addition, the control unit 500 includes a host I / F (interface) 506 for transmitting and receiving data and signals to and from the host device 90 that is an information processing device such as a personal computer.

  The control unit 500 also includes a recording head drive control unit 507 and a recording head driver 508 for driving and controlling the recording head 14a, a processing agent discharge head drive control unit 521 and a process for driving and controlling the processing agent discharge head 14b. And an agent discharge head driver 522.

  Further, the control unit 500 inputs detection signals from the main scanning motor driving unit 511 for driving the main scanning motor 510, the sub scanning motor driving unit 513 for driving the sub scanning motor 512, and various sensors 518. I / O 516 is provided.

  In addition, an operation panel 517 for inputting and displaying information necessary for the apparatus is connected to the control unit 500. Further, the control unit 500 performs on / off switching and output polarity switching control of a high-voltage circuit (high-voltage power supply) 514 that applies a high voltage to the charging roller 34.

  The operation of the control unit 500 having the above configuration will be described. The host I / F 506 receives print data including image data from a data processing device such as a personal computer, an image reading device such as an image scanner, and a host device 90 such as an imaging device such as a digital camera via a cable or a network. . Note that print data is generated and output to the control unit 500 by the printer driver 91 on the host device 90 side.

  The CPU 501 reads and analyzes the print data in the reception buffer included in the host I / F 506, performs data rearrangement processing by the ASIC 505, and transfers the recording image data to the head drive control unit 507. Note that the conversion of print data for image output into bitmap data is performed by developing the image data into bitmap data by the printer driver 91 on the host device 90 side and transferring it to this device as described above. However, font data may be stored in the ROM 502, for example.

  When the print head drive control unit 507 receives image data (dot pattern data) corresponding to one row of the print head 14a, the print head driver 508 synchronizes the dot pattern data for one row with a clock signal. Serial data, and a latch signal is sent to the recording head driver 508 at a predetermined timing.

  The recording head drive control unit 507 performs D / A conversion on the ROM (which can also be constituted by the ROM 502) storing drive waveform (drive signal) pattern data and the drive waveform data read from the ROM. A waveform generation circuit including a D / A converter and a drive waveform generation circuit including an amplifier and the like are included.

  The print head driver 508 also latches a shift register that receives a clock signal from the print head drive control unit 507 and serial data that is image data, and a register value of the shift register using a latch signal from the print head drive control unit 507. ON / OFF of the analog switch array, including a latch circuit for switching, a level conversion circuit (level shifter) for changing the output value of the latch circuit, and an analog switch array (switch means) whose ON / OFF is controlled by this level shifter By controlling the above, the required drive waveform included in the drive waveform is selectively applied to the actuator means of the recording head 14a to drive the head.

  The processing agent discharge head drive control unit 521 and the processing agent discharge head driver 522 are configured in the same manner as the recording head drive control unit 507 and the recording head driver 508, respectively, and the processing agent discharge head 14b is based on the processing agent adhesion data. Drive.

<Functional block diagram of the part that executes the image forming method>
FIG. 8 is a functional block diagram of a part that executes the image forming method according to each embodiment of the present invention in the control unit 500. All of these functional blocks can be configured by software processing by the CPU 501, or part of the functional blocks can be configured by software processing by the CPU 501 and the rest can be configured by the ASIC 505. Further, the printer driver 91 in the host device 90 can be used.

  As shown in the figure, the image forming method according to the present embodiment is executed by a color boundary determination unit 601, a processing agent placement region setting unit 602, a processing agent placement unit 603, and a halftone processing unit 604.

  A color boundary determination unit 601 serving as a color boundary detection unit determines a color boundary part of an image formed by this image data in pixel units from KCMY 8-bit image data (colorant data) as input data. Here, the input data may be RGB 8-bit image data.

  A processing agent driving area setting unit 602 constituting the processing agent adhesion data generation unit and the recording image data generation unit is configured to process the processing agent driving area based on the determination output (color boundary determination data) of the color boundary determination unit 601. The color material data at the color boundary is thinned out, and processing agent driving area data and KCMY 8-bit intermediate data with the color boundary thinned out are generated.

  The processing agent placement unit 603 constituting the processing agent adhesion data generation means outputs AB... 2 bits of processing agent placement data based on the processing agent placement area data. The halftone processing unit 604 converts the KCMY 8-bit intermediate data with the color boundary portion thinned out into dot data, and generates KCMY 2-bit colorant dot arrangement data. If the input data is RGB, conversion to KCMY is also performed.

<Processing agent setting area setting process>
FIG. 9 is a flowchart for explaining the processing agent placement region setting processing according to the embodiment of the present invention, that is, the processing of the color boundary determination unit 601 and the processing agent placement region setting unit 602 in FIG.

  KCMY 8-bit image data is input to the color boundary determination unit 601 (step S1). The color boundary determination unit 601 refers to the KCMY-L * a * b table 701 stored in the ROM 502, and calculates the color difference ΔE between the target pixel i and the adjacent pixel n (step S2).

Here, the adjacent pixel n is a pixel located right next to the pixel i of interest in the main scanning direction (horizontal direction) (following in time). The color difference ΔE is calculated by the following equation [1].
ΔE = √ {(L _i ^* −L _n ^* ) ² + (a _i ^* −a _n ^* ) ² + (b _i ^* −b _n ^* ) ² } Formula [1]

  Next, the color boundary determination unit 601 refers to the color boundary threshold value Th1 stored in the ROM 502 and determines whether or not the color difference ΔE exceeds the color boundary threshold value Th1 (step S3). That is, when the color difference ΔE exceeds the color boundary threshold Th1, it is determined that there is a color boundary between the pixel of interest i and the adjacent pixel n. The color boundary threshold Th1 is set by examining in advance a value at which boundary blurring easily occurs.

When the color difference ΔE exceeds the color boundary threshold value Th1 (step S3: Yes), the processing agent driving region setting unit 602 designates the pixel of interest i as the processing agent driving region p and thins out KCMY data (step S4). . Here, to designate the target pixel i as the processing agent implantation region p is to convert (i, n) into (p, n). In addition, thinning out KCMY data means converting (K _i , C _i , M _i , Y _i ) to (0, 0, 0, 0).

  After executing Step S4, the process proceeds to Step S5. If it is determined in step S3 that the color difference ΔE does not exceed the color boundary threshold Th1 (step S3: No), the process proceeds to step S5.

  In step S5, the target pixel i is moved. The moving direction is right next to the main scanning direction. When the right end of one line is reached, the process proceeds to the left end of the next line. It can also be moved within a range of N × M pixels composed of N pixels in the main scanning direction and M pixels in the sub-scanning direction.

  Next, the processing agent implantation region setting unit 602 determines whether or not scanning of all pixels is completed, that is, whether or not all pixels of the input data are the target pixel i (step S6). As a result of the determination, when the scanning of all the pixels is completed (step S6: Yes), the processing agent driving region data 703 and the intermediate data 704 are output, and the processing agent driving region setting process is ended. If scanning of all pixels has not been completed (step S6: No), the process returns to step S2.

<Processing agent arrangement data generation process>
FIG. 10 is a flowchart for explaining the processing agent arrangement data generation processing according to the embodiment of the present invention, that is, the processing of the processing agent arrangement unit 603 in FIG.

  The processing agent placement area data 703 is input to the processing agent placement unit 603 (step S11). The processing agent placement unit 603 calculates the distance from the target pixel pi to the nearest colorant data, with the pixel specified in the processing agent driving region p as the target pixel pi (step S12).

  When the distance from the pixel of interest pi to the nearest colorant data is calculated, the processing agent configuration-penetration amount table 706 stored in the ROM 502, that is, the table showing the relationship shown in FIG. The processing agent to be attached to the gap formed in the step is determined (step S13). For example, the shorter the distance, the more penetrating treatment agent is determined to adhere.

  Next, the processing agent arranging unit 603 moves the target pixel pi (step S14). Next, it is determined whether or not the scanning of all the pixels has been completed, that is, whether or not all the pixels in the processing agent driving region data are set as the target pixel pi (step S15).

  As a result of the determination, when the scanning of all the pixels is completed (step S15: Yes), the processing agent arrangement data 707 is output, and the processing agent arrangement data generation process is finished. If scanning of all pixels has not been completed (step S15: No), the process returns to step S12.

FIG. 11 is a diagram for explaining steps S12 and S13 in FIG.
Here, FIG. 11A shows a state in which the center pixel of 5 rows × 5 columns is set as the target pixel pi of the processing agent injection region, and FIG. 11B shows the target pixel pi before the movement while moving the target pixel pi. The calculated distance difference data is shown. FIG. 11C shows distance difference data calculated for all the pixels in the processing agent driving region, and FIG. 11D shows a processing agent determined according to the distance difference data. Further, in FIG. 11A, the target pixel pi and the white area indicate the processing agent injection area.

  In step S12 of FIG. 10, a distance difference between the target pixel pi and the right and left colorant data (colorant pixel) is calculated in units of pixels. In the case of FIG. 11A, the distance from the pixel of interest pi to the left and right colorant data is 2 for both left and right, so the distance difference is 0. Therefore, as shown in FIG. 11B, the numerical value of the center pixel of 5 rows × 5 columns is set to 0.

  Similarly, when the pixel of interest pi is moved in the processing agent injection region, and the distance to the left and right colorant data is calculated for all the pixels in the processing agent injection region, the result shown in FIG. 11C is obtained.

  Here, the numerical value is 0 when the pixel of interest pi is located at the center of the left and right two color ends. The numerical value is small (here, 1) when the distance to the ends of the two left and right colors is different but the difference is small. The numerical value becomes a large value (2 in this case) when the distances to the ends of the left and right two colors are different and the difference is large.

  In step S13, the processing agent is set for each numerical value in FIG. 11C using the processing agent configuration-penetration amount table 706.

  In this embodiment, as shown in FIG. 11D, the larger the numerical value, the larger the penetration amount treatment agent is set, and the smaller the numerical value, the smaller the penetration amount treatment agent is set. That is, a large droplet of treatment agent B (B in the figure) for numerical value 2, a small droplet of treatment agent A (numeric value in the figure) for numerical value 1, and a small droplet of treatment agent B for numerical value 0 (B in the figure) was set.

  Here, the correction effect of various treatment agent arrangement patterns in the treatment agent arrangement data 707 is examined in advance with respect to the various colorant arrangement patterns in the treatment agent placement region data 703, and the colorant arrangement pattern and the best treatment agent arrangement pattern are checked. You can also create a table of combinations of With this configuration, for example, when the processing agent placement area data 703 having the colorant arrangement pattern shown in FIG. 11A is input, the processing agent arrangement data 707 having the processing agent arrangement pattern shown in FIG. 11D is acquired from the table. Thus, the distance calculation in step S12 can be omitted.

<Image Forming Apparatus According to Second Embodiment>
FIG. 12 is a diagram for explaining a schematic configuration of a main part of an image forming apparatus according to the second embodiment of the present invention. In this figure, the same reference numerals as those in FIG. 6 are assigned to the same or corresponding parts as those in FIG. 6 (the image forming apparatus according to the first embodiment). This image forming apparatus can execute the image forming method according to the seventh embodiment of the present invention.

  In this image forming apparatus, a roll-shaped non-penetrable medium 50 is loaded as a recording medium. A plurality of heaters 41 for heating the non-penetrable medium 50 are disposed below the conveyance path of the non-penetrable medium 50. The recording head 14a and the processing agent discharge head 14b are mounted on respective carriages (not shown), and the distance between the carriages is configured to be variable. In addition, a hot air generating unit 39 is disposed downstream of the processing agent discharge head 14b in the transport direction of the non-penetrable medium 50 to apply hot air to the ink dots and the processing agent attached to the non-penetrable medium 50 and dry them. ing. The configuration of the control unit of the image forming apparatus is obtained by adding a drive unit for the warm air generating unit 39 to FIG. 7 (the control unit of the image forming apparatus according to the first embodiment).

  In this image forming apparatus, when an image is formed on the non-penetrable medium 50, the non-penetrable medium 50 is heated by the heater 41, whereby the ink dots ejected from the recording head 14a and the process ejected from the processing agent ejecting head 14b. The agent easily adheres to the surface of the non-penetrable medium 50. In addition, by fixing the ink dots and the treatment agent attached to the surface of the non-penetrable medium 50 by applying hot air to the ink dots and the treatment agent, the fixability of the ink dots and the treatment agent can be improved.

  Further, by adjusting the distance between the recording head 14a and the processing agent discharge head 14b, the degree of drying of the ink dots when the processing agent is discharged can be changed, and the degree of the effect of reducing the color boundary blurring caused by the processing agent can be changed. .

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus main body, 2 ... Image forming part, 3 ... Paper, 14a ... Recording head, 14b ... Treatment agent discharge head, 50 ... Non-penetration medium, 601 ... Color boundary determination part, 602 ... Treatment agent implantation area | region setting part 603 ... Treatment agent placement part.

Japanese Patent No. 4827450

Claims (12)

A recording head for attaching ink dots to a recording medium;
A treatment agent attaching portion for attaching a treatment agent for controlling the spread of ink dots to the recording medium;
Color boundary detection means for detecting color boundary image data that is image data of the color boundary from the image data;
Based on the image data and the color boundary image data, recording image data generating means for generating recording image data for attaching ink dots to the recording medium so that a gap is formed in the color boundary portion;
Based on the color boundary image data, processing agent adhesion data generating means for generating processing agent adhesion data for attaching the processing agent to the gap,
An image forming apparatus. The image forming apparatus according to claim 1,
The color boundary detection unit is an image forming apparatus that detects the color boundary image data based on a color difference between adjacent image data. The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the recording image data generating means includes means for thinning out the color boundary image data from the image data. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the recording image data includes data for changing an area or a position of the gap by changing a size or a position of the ink dot. The image forming apparatus according to claim 1,
The processing agent adhesion data is an image forming apparatus including data for attaching treatment agents having different penetration amounts according to the distance between the gap and the ink dot. The image forming apparatus according to claim 1,
The processing agent adhesion data is an image forming apparatus including data indicating a size or position of a dot of the treatment agent to be adhered to the gap. The image forming apparatus according to claim 1,
An image forming apparatus comprising: means for heating the recording medium; and means for drying the ink dots and the processing agent attached to the recording medium. A color boundary detection step of detecting color boundary image data that is image data of the color boundary from the image data;
Based on the image data and the color boundary image data, an ink dot attaching step for attaching ink dots to a recording medium so that a gap is formed in the color boundary portion;
A processing agent attaching step for attaching a processing agent for controlling the spread of ink dots to the gap based on the color boundary image data;
An image forming method comprising: The image forming method according to claim 8.
An image forming method including an overcoat forming step of attaching the treatment agent to the entire portion where the ink dot is adhered in the ink dot attachment step and the portion where the treatment agent is adhered in the treatment agent attachment step.   A program for causing a computer to function as each unit of the image forming apparatus according to claim 1. A recording head for attaching ink dots to a recording medium;
A treatment agent attaching portion for attaching a treatment agent for controlling the spread of ink dots to the recording medium;
A control unit that controls the recording head so as to leave a gap in the color boundary, and controls the treatment agent adhering part so that the treatment agent adheres to the gap;
An image forming apparatus. An ink dot attaching step for attaching ink dots to a recording medium so that a gap is formed in the color boundary portion based on the image data and the color boundary image data;
A processing agent attaching step for attaching a processing agent for controlling the spread of ink dots to the gap based on the color boundary image data;
An image forming method comprising:

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