JP5094269B2 - Image processing method, program, storage medium, image processing apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to an image processing method, a program, a storage medium, an image processing apparatus, and an image forming apparatus.

  2. Description of the Related Art As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, and a multifunction machine of these, for example, a liquid ejection type image forming apparatus using a liquid ejection head (droplet ejection head) as a recording head is known. This liquid discharge type image forming apparatus means a sheet (not limited to paper but including OHP, etc., and means that a liquid, other liquid, etc. can adhere to the recording head. , Recording paper, recording paper, recording material, recording material, medium, etc.) by discharging a recording liquid (hereinafter also referred to as “ink”) to form an image (recording, printing, printing, printing) Used in synonyms).

  In such an image forming apparatus, when black ink (black recording liquid) and color ink (color recording liquid) such as cyan (C) and magenta (M, yellow (Y)) are used, reproduction of a black image is as follows. Reproduction using color ink is performed.

For example, Patent Document 1 discloses that when an image is formed on a recording medium, black is reproduced using a color other than black ink, or black is reproduced by mixing black ink and color ink other than black ink. Possible image forming apparatuses are described.
JP-A-2005-329706

In Patent Document 2, when a black image area touches a boundary with a color image area, the black image area is divided into black ink dots (area ratio of 50% or less) arranged in a checkered pattern, and three colors of cyan, magenta, and yellow. The document describes that ink dots (the dot area ratios of the respective colors are the same) are combined.
Japanese Patent Laid-Open No. 10-034977

Patent Document 3 includes a first ink ejection unit that ejects black ink and a second ink ejection unit that ejects ink of a color other than black. The first resolution and the first resolution An image can be printed on a medium at a low second resolution, and when printing an image at the second resolution based on print data for monochrome printing, ink of another color is printed from the second ink ejection unit. It is described that the image is printed by discharging toward the end.
JP 2005-335138 A

In Patent Document 4, when recording a color image using black ink with low penetrability and color ink with high penetrability, some of the pixels to be printed in black are black ink. Pixels to be printed in black adjacent to some pixels are printed with color ink dots using any one of the color inks instead of black printing. It is described.
Japanese Patent No. 3291828

Patent Document 5 discloses a printing signal for ejecting ink from a nozzle opening row for ejecting black ink and a printing signal for ejecting ink from a nozzle opening row for ejecting cyan, magenta, and yellow inks in the monochrome printing mode. Is output, and a pseudo black dot is formed by mixing cyan, magenta, and yellow ink adjacent to a dot formed by black ink.
Japanese Patent Laid-Open No. 08-281973

In Patent Document 6, when performing black and white printing, printing is performed at a pixel pitch twice that of color printing with black dots obtained by superimposing yellow, magenta, and cyan inks and black dots of black ink. It is described that the discharge amount of yellow, magenta, and cyan inks is approximately 2/3 of the discharge amount of black ink.
Japanese Patent Laid-Open No. 10-034981

In Patent Document 7, when the data relating to the black ink of the two pixels of the pixel of interest and the adjacent pixel is data that is ejected and the other is non-ejected data, the data of these two pixels is yellow, magenta, and cyan. Re-binarization with the data of the target pixel as non-ejection data when both are non-ejection data. Processing is described.
Japanese Patent Laid-Open No. 2000-015798

  By the way, in a liquid ejection type image forming apparatus, when a nozzle of a recording head is clogged, ejection failure such as inability to eject or ejection bend occurs. The state of the nozzle is maintained and recovered by performing an idle ejection operation for ejecting liquid droplets that do not contribute to image formation at a required timing, such as every time the state has elapsed.

  Therefore, in the image forming apparatus capable of forming a color image using black ink and color ink as described above, when the state of forming a monochrome image (black image) continues, image formation is performed using only black ink. As a result, for the color ink nozzles that are not used during monochrome image formation, the drying of the ink near the nozzles proceeds and clogging is likely to occur. As a result, in order to prevent clogging of the color nozzle, it is necessary to frequently perform maintenance such as idle discharge operation, which has a great influence on the recording speed and the recording cost.

  On the other hand, the above-described image forming apparatuses described in various documents attempt to improve the image quality by forming a black image itself using color ink. If the color ink is replaced, the image quality will be degraded, or only the color ink will be consumed even though only the black image is printed, which will be misleading to the user. Become.

  The present invention has been made in view of the above-described problems, and an image processing method for preventing clogging of nozzles for color recording liquid by performing substantially idle ejection of the color recording liquid when printing a black image. An object of the present invention is to provide a program for causing a computer to execute the image processing method, a storage medium storing the program, an image processing apparatus for executing the image processing method, and an image forming apparatus for executing the image processing method.

In order to solve the above problems, an image processing method according to the present invention includes:
In an image processing method for generating image data of an image output by an image forming apparatus capable of forming an image using a black recording liquid and at least one color recording liquid,
When the input image is black, the image is formed with the black recording liquid, and the image data for generating the color recording liquid is used for the image ,
In the image data, the amount of black recording liquid used per unit area is 20 to 100% when an image having the same density is formed using only the black recording liquid, and the amount of color recording liquid used for each color per unit area. Is an amount of 5 to 35% of the case where an image having the same density is formed with only the black recording liquid, and data for forming dots of the black recording liquid and the color recording liquid at the same position, and
The image data is data in which the dots of the color recording liquid are arranged at half or more of the positions where the dots of the black recording liquid are arranged with a gradation of 90% or more,
When using two or more color recording liquids, make the dot placement and dot size of each color the same,
For each color recording liquid, dots of each color are arranged in halftone processing using the same dither mask,
While forming an image with the black recording liquid, performing a jaggy correction for correcting a step-like change portion of the image for a black character image that uses the color recording liquid for the image, and
The jaggy correction includes a correction pattern for performing jaggy correction for correcting a step-like change portion of an image for a single color character composed of one color recording liquid, and an image pattern of a character using a black recording liquid and a color recording liquid. The composition was made by synthesis .

According to the onset bright, and can be performed substantially empty discharge by using a color recording liquid when forming the black color image, it can be prevented and clogging of the nozzles for color recording liquid.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an image forming apparatus that outputs image data generated by an image processing method according to the present invention will be described with reference to FIGS. FIG. 1 is an explanatory side view for explaining the overall structure of the mechanism section of the image forming apparatus, and FIG. 2 is a plan view for explaining the mechanism section.
In this image forming apparatus, a carriage 3 is slidably held in a main scanning direction by a guide rod 1 and a guide rail 2 which are guide members horizontally mounted on left and right side plates (not shown), and a driving pulley 6A is driven by a main scanning motor 4. 2 is moved and scanned in the direction indicated by the arrow (main scanning direction) in FIG. 2 via a timing belt 5 stretched between the roller and the driven pulley 6B.

  For example, yellow (Y), cyan (C), and magenta (M) ink droplets that are color recording liquids and black (K) ink droplets that are black recording liquids are ejected onto the carriage 3. Four recording heads 7y, 7c, 7m, 7k (referred to as “recording head 7” when colors are not distinguished) are arranged in a direction crossing the main scanning direction. The ink droplet ejection direction is directed downward.

  The liquid discharge head constituting the recording head 7 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. A shape memory alloy actuator using an electrostatic force, an electrostatic actuator using an electrostatic force, and the like provided as pressure generating means for generating a pressure for discharging a droplet can be used.

  In addition, the configuration is not limited to an independent head for each color, and may be configured with one or a plurality of liquid ejection heads having a nozzle row composed of a plurality of nozzles that eject droplets of a plurality of colors. Further, a head configuration using six color inks in which red (R) and blue (B) are added to the four colors of KCMY, and six color inks in which light cyan (LC) and light magenta (LM) are added to the four colors of KCMY are used. Head configuration, head configuration using 7 color inks that are KCMY 4 colors light cyan (LC), light magenta (LM), red (R), KCMY 4 colors light cyan (LC), light magenta (LM), It is also possible to adopt a head configuration using seven color inks to which dark yellow (DY) is added.

  The carriage 3 is also equipped with sub-tanks 8 for each color for supplying ink of each color to the recording head 7. Ink is supplied to the sub tank 8 from a main tank (ink cartridge) (not shown) via an ink supply tube 9.

  On the other hand, as a paper feeding unit for feeding paper 12 stacked on a paper stacking unit (pressure plate) 11 such as a paper feeding cassette 10, a half-moon roller (for separating and feeding the paper 12 one by one from the paper stacking unit 11) A separation pad 14 made of a material having a large friction coefficient is provided facing the sheet feeding roller 13 and the sheet feeding roller 13, and the separation pad 14 is urged toward the sheet feeding roller 13 side.

  In order to convey the sheet 12 fed from the sheet feeding unit below the recording head 7, a conveyance belt 21 for electrostatically attracting and conveying the sheet 12 and a guide 15 from the sheet feeding unit. A counter roller 22 for transporting the sheet 12 fed between the conveyor belt 21 and the conveyor belt 21, and for shifting the sheet 12 fed substantially vertically upward by approximately 90 ° to follow the conveyor belt 21. A conveyance guide 23 and a pressing roller 25 urged toward the conveyance belt 21 by a pressing member 24 are provided. In addition, a charging roller 26 as a charging unit for charging the surface of the transport belt 21 is provided.

  Here, the conveyance belt 21 is an endless belt, is stretched between the conveyance roller 27 and the tension roller 28, and the conveyance roller 27 rotates from the sub-scanning motor 31 via the timing belt 32 and the timing roller 33. By doing so, it is configured to circulate in the belt conveyance direction (sub-scanning direction) of FIG. A guide member 29 is disposed on the back side of the conveying belt 21 corresponding to the image forming area by the recording head 7. The charging roller 26 is disposed so as to come into contact with the surface layer of the transport belt 21 and rotate following the rotation of the transport belt 21.

  Further, as shown in FIG. 2, a slit disk 34 is attached to the shaft of the transport roller 27, and a sensor 35 for detecting the slit of the slit disk 34 is provided. A rotary encoder 36 is configured.

  Further, as a paper discharge unit for discharging the paper 12 recorded by the recording head 7, a separation claw 51 for separating the paper 12 from the transport belt 21, a paper discharge roller 52 and a paper discharge roller 53, and a discharge And a paper discharge tray 54 for stocking the paper 12 to be printed.

  A double-sided paper feeding unit 55 is detachably mounted on the back. The double-sided paper feeding unit 55 takes in the paper 12 returned by the reverse rotation of the transport belt 21, reverses it, and feeds it again between the counter roller 22 and the transport belt 21.

  Further, as shown in FIG. 2, a maintenance / recovery mechanism 56 for maintaining and recovering the nozzle state of the recording head 7 is disposed in the non-printing area on one side of the carriage 3 in the scanning direction.

  The maintenance / recovery machine 56 is provided with caps 57 for capping each nozzle surface of the recording head 7, a wiper blade 58 as a blade member for wiping the nozzle surface, and for discharging the thickened recording liquid. An empty discharge receiver 59 for receiving droplets when performing an empty discharge for discharging droplets that do not contribute to recording is provided.

  In the image forming apparatus configured as described above, the sheets 12 are separated and fed one by one from the sheet feeding unit, and the sheet 12 fed substantially vertically upward is guided by the guide 15, and includes the transport belt 21 and the counter roller 22. The leading end is guided by the conveying guide 23 and pressed against the conveying belt 21 by the pressing roller 25, and the conveying direction is changed by approximately 90 °.

  At this time, a control unit (not shown) applies an alternating voltage that alternately repeats positive and negative to the charging roller 26 from the AC bias supply unit, and a charging voltage pattern that alternates the conveying belt 21, that is, a sub-scanning direction that is a circumferential direction. In addition, charging is performed with a pattern in which plus and minus are alternately repeated with a predetermined width. When the paper 12 is fed onto the charged transport belt 21, the paper 12 is attracted to the transport belt 21 by electrostatic force, and the paper 12 is transported in the sub-scanning direction by the circular movement of the transport belt 21.

  Therefore, by driving the recording head 7 according to the image signal while moving the carriage 3 in the forward and backward directions, ink droplets are ejected onto the stopped paper 12 to record one line. After transporting a predetermined amount, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing edge of the paper 12 has reached the recording area, the recording operation is finished and the paper 12 is discharged onto the paper discharge tray 54.

  In the case of double-sided printing, when recording on the front surface (surface to be printed first) is completed, the recording belt 12 is fed into the double-sided paper feeding unit 61 by rotating the conveyor belt 21 in the reverse direction. The paper 12 is reversed (with the back surface being the printing surface), fed again between the counter roller 22 and the transport belt 21, controlled in timing, and transported onto the transport bell 21 as described above. After recording on the back side, the sheet is discharged onto the discharge tray 54.

  During printing (recording) standby, the carriage 3 is moved to the maintenance / recovery mechanism 55 side, and the nozzle surface of the recording head 7 is capped by the cap 57, and the nozzles are kept in a wet state. To prevent. In addition, the recording liquid is sucked from the nozzle in a state where the recording head 7 is capped by the cap 57, and a recovery operation is performed to discharge the thickened recording liquid and bubbles, and the ink adhered to the nozzle surface of the recording head 7 by this recovery operation. Wiping is performed with a wiper blade 58 in order to clean and remove. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. Thereby, the stable ejection performance of the recording head 7 is maintained.

  Next, an example of the liquid discharge head constituting the recording head 7 will be described with reference to FIGS. 3 is a cross-sectional explanatory diagram along the longitudinal direction of the liquid chamber of the head, and FIG. 4 is a cross-sectional explanatory diagram of the head along the lateral direction of the liquid chamber (nozzle arrangement direction).

  This liquid discharge head includes, for example, a flow path plate 101 formed by anisotropic etching of a single crystal silicon substrate, a vibration plate 102 formed by, for example, nickel electroforming bonded to the lower surface of the flow path plate 101, a flow path A nozzle plate 103 joined to the upper surface of the plate 101 is joined and laminated, and a nozzle communication path 105 that is a flow path through which a nozzle 104 that discharges droplets (ink droplets) communicates therewith and a liquid chamber that is a pressure generation chamber. 106, an ink supply port 109 communicating with a common liquid chamber 108 for supplying ink to the liquid chamber 106 through a fluid resistance portion (supply path) 107 is formed.

  In addition, two rows (only one row is shown in FIG. 6) of stacked piezoelectric elements as electromechanical conversion elements that are pressure generating means (actuator means) for pressurizing ink in the liquid chamber 106 by deforming the diaphragm 102. An element 121 and a base substrate 122 to which the piezoelectric element 121 is bonded and fixed are provided. Note that a column portion 123 is provided between the piezoelectric elements 121. This support portion 123 is a portion formed simultaneously with the piezoelectric element 121 by dividing and processing the piezoelectric element member. However, since the drive voltage is not applied, the support portion 123 becomes a simple support. Further, an FPC cable 126 equipped with a drive circuit (drive IC) (not shown) is connected to the piezoelectric element 121.

  The peripheral edge of the diaphragm 102 is joined to a frame member 130, and the frame member 130 serves as a through-hole 131 and a common liquid chamber 108 that house an actuator unit composed of the piezoelectric element 121 and the base substrate 122. A recess and an ink supply hole 132 for supplying ink from the outside to the common liquid chamber 108 are formed. The frame member 130 is formed by injection molding with a thermosetting resin such as an epoxy resin or polyphenylene sulfite, for example.

  Here, the flow path plate 101 is formed by, for example, subjecting the single crystal silicon substrate having a crystal plane orientation (110) to anisotropic etching using an alkaline etching solution such as an aqueous potassium hydroxide solution (KOH), so that the nozzle communication path 105, Although a recess or a hole serving as the liquid chamber 106 is formed, the invention is not limited to a single crystal silicon substrate, and other stainless steel substrates, photosensitive resins, and the like can also be used.

  The vibration plate 102 is formed from a nickel metal plate, and is manufactured by, for example, an electroforming method (electroforming method). Alternatively, a metal plate or a joining member between a metal and a resin plate may be used. it can. The piezoelectric element 121 and the support post 123 are bonded to the diaphragm 102 with an adhesive, and the frame member 130 is further bonded with an adhesive.

  The nozzle plate 103 forms a nozzle 104 having a diameter of 10 to 30 μm corresponding to each liquid chamber 106 and is bonded to the flow path plate 101 with an adhesive. The nozzle plate 103 is formed by forming a water repellent layer on the outermost surface of a nozzle forming member made of a metal member via a required layer.

  The piezoelectric element 121 is a stacked piezoelectric element (here, PZT) in which piezoelectric materials 151 and internal electrodes 152 are alternately stacked. An individual electrode 153 and a common electrode 154 are connected to each internal electrode 152 drawn out to different end faces of the piezoelectric element 121 alternately. In this embodiment, the ink in the liquid chamber 106 is pressurized using the displacement in the d33 direction as the piezoelectric direction of the piezoelectric element 121. However, the pressure in the d31 direction is used as the piezoelectric direction of the piezoelectric element 121. The ink in the liquid chamber 106 may be pressurized. Alternatively, a structure in which one row of piezoelectric elements 121 is provided on one substrate 122 may be employed.

  In the liquid discharge head having such a configuration, for example, by lowering the voltage applied to the piezoelectric element 121 from the reference potential, the piezoelectric element 121 contracts, and the diaphragm 102 descends to expand the volume of the liquid chamber 106. Then, the ink flows into the liquid chamber 106, and then the voltage applied to the piezoelectric element 121 is increased to extend the piezoelectric element 121 in the stacking direction, and the diaphragm 102 is deformed in the direction of the nozzle 104, so that the volume / volume of the liquid chamber 106 is increased. By contracting the volume, the recording liquid in the liquid chamber 106 is pressurized, and droplets of the recording liquid are ejected (jetted) from the nozzle 104.

  Then, by returning the voltage applied to the piezoelectric element 121 to the reference potential, the diaphragm 102 is restored to the initial position, and the liquid chamber 106 expands to generate a negative pressure. The recording liquid is filled in 106. Therefore, after the vibration of the meniscus surface of the nozzle 104 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and striking or pushing can be performed depending on the direction of the drive waveform.

Next, an outline of the control unit of the image forming apparatus will be described with reference to the block diagram of FIG.
The control unit 200 also serves as a means for correcting the contour portion (means for performing jaggy correction) according to the present invention, and includes a CPU 211 that controls the entire apparatus, and a program that includes the program according to the present invention executed by the CPU 211. ROM 202 for storing other fixed data, RAM 203 for temporarily storing image data and the like, rewritable nonvolatile memory 204 for retaining data even while the apparatus is powered off, and various kinds of image data It includes an ASIC 205 that processes image processing for performing signal processing, rearrangement, and the like, and other input / output signals for controlling the entire apparatus.

  The control unit 200 also includes an I / F 206 for transmitting and receiving data and signals to and from the host, data transfer means for driving and controlling the recording head 7, and drive waveform generation means for generating a drive waveform. A print control unit 207; a head driver (driver IC) 208 for driving the recording head 7 provided on the carriage 3 side; a motor driving unit 210 for driving the main scanning motor 4 and the sub-scanning motor 31; An AC bias supply unit 212 that supplies an AC bias to the roller 34, detection signals from the encoder sensors 43 and 35, and various sensors such as a temperature sensor 215 that detects an environmental temperature as a factor causing a shift in the dot formation position. An I / O 213 for inputting a detection signal is provided. The control unit 200 is connected to an operation panel 214 for inputting and displaying information necessary for the apparatus.

  Here, the control unit 200 transmits image data from the host side such as an information processing device such as a personal computer, an image reading device such as an image scanner, an imaging device such as a digital camera, etc. via an I / F 206 via a cable or a network. Receive.

  Then, the CPU 201 of the control unit 200 reads and analyzes the print data in the reception buffer included in the I / F 206, performs necessary image processing, data rearrangement processing, and the like in the ASIC 205, and drives the image data to the head drive. The data is transferred from the control unit 207 to the head driver 208. Note that generation of dot pattern data for outputting an image is performed by a printer driver on the host side as will be described later.

  The print control unit 207 transfers the above-described image data to the head driver 208 as serial data, and transmits a transfer clock, a latch signal, a droplet control signal (mask signal), and the like necessary for the transfer of the image data and confirmation of the transfer. In addition to the output to the head driver 208, a drive waveform generator and a head driver composed of a D / A converter, a voltage amplifier, a current amplifier, etc. for D / A converting the pattern data of the drive signal stored in the ROM Drive waveform selection means for generating a drive waveform composed of one drive pulse (drive signal) or a plurality of drive pulses (drive signal) and outputting the drive waveform to the head driver 208.

  The head driver 208 selectively selects droplets of the recording head 7 based on image data corresponding to one line of the recording head 7 input serially, and forms a driving signal provided from the print control unit 207. The recording head 7 is driven by applying it to a driving element (for example, a piezoelectric element as described above) that generates energy to be discharged. At this time, by selecting a driving pulse constituting the driving waveform, for example, dots having different sizes such as large droplets (large dots), medium droplets (medium dots), and small droplets (small dots) can be distinguished. it can.

  Further, the CPU 201 detects a speed detection value and a position detection value obtained by sampling a detection pulse from the encoder sensor 43 constituting the linear encoder, and a speed target value and a position target value obtained from a previously stored speed / position profile. Based on this, a drive output value (control value) for the main scanning motor 4 is calculated, and the main scanning motor 4 is driven via the motor driving unit 210. Similarly, based on the speed detection value and position detection value obtained by sampling the detection pulse from the encoder sensor 35 constituting the rotary encoder, and the speed target value and position target value obtained from the previously stored speed / position profile. Then, a drive output value (control value) for the sub-scanning motor 31 is calculated, and the sub-scanning motor 31 is driven via the motor driver 210 and the motor driver.

Next, an example of the print control unit 207 and the head driver 208 will be described with reference to FIG.
As described above, the print control unit 207 generates a drive waveform (common drive waveform) composed of a plurality of drive pulses (drive signals) within one printing cycle, and outputs a print waveform. And a data transfer unit 302 that outputs a clock signal, a latch signal (LAT), and droplet control signals M0 to M3.

  The droplet control signal is a 2-bit signal that instructs each droplet to open and close an analog switch 317, which will be described later, of the head driver 208. The droplet control signal is a waveform to be selected according to the printing cycle of the common drive waveform. State transition is made to level (ON), and state transition is made to L level (OFF) when not selected.

  The head driver 208 receives a transfer clock (shift clock) and serial image data (gradation data: 2 bits / CH) from the data transfer unit 302, and each register value of the shift register 311 by a latch signal. A latch circuit 312 for latching, a decoder 313 that decodes gradation data and control signals M0 to M3 and outputs the result, and a logic level voltage signal of the decoder 313 is converted to a level at which the analog switch 315 can operate. Level shifter 314, and an analog switch 316 that is turned on / off (opened / closed) by the output of the decoder 313 provided via the level shifter 314.

  The analog switch 316 is connected to the selection electrode (individual electrode) 154 of each piezoelectric element 121, and the common drive waveform from the drive waveform generation unit 301 is input thereto. Accordingly, when the analog switch 316 is turned on in accordance with the result of decoding the serially transferred image data (gradation data) and the control signals MN0 to MN3 by the decoder 313, a required drive signal constituting the common drive waveform is obtained. Passing (selected) is applied to the piezoelectric element 121.

Next, an example of the drive waveform will be described with reference to FIGS.
As shown in FIG. 7, the drive waveform generation unit 301 includes a waveform element that falls from the reference potential Ve and a waveform element that rises from the state after the fall within one printing cycle (one drive cycle). A drive signal (drive waveform) composed of eight drive pulses P1 to P8 is generated and output. On the other hand, the driving pulse to be used is selected by the droplet control signals M0 to M3 from the data transfer unit 302.

  Here, the waveform element in which the potential V of the drive pulse falls from the reference potential Ve is a drawing waveform element in which the piezoelectric element 121 contracts and the volume of the pressurized liquid chamber 106 expands. Further, the waveform element that rises from the state after the fall is a pressurizing waveform element that causes the piezoelectric element 121 to expand and the volume of the pressurized liquid chamber 106 to contract.

  Then, when forming a small droplet (small dot) by the droplet control signals M0 to M3 from the data transfer unit 302, the drive pulse P1 is selected as shown in FIG. 8A to form a medium droplet (medium dot). When driving, the driving pulses P4 to P6 are selected as shown in FIG. 8B, and when forming large droplets (large dots), the driving pulses P2 to P8 are selected as shown in FIG. When the meniscus is vibrated without droplet ejection, the fine drive pulse P2 is selected as shown in FIG. 8D and applied to the piezoelectric element 121 of the recording head 7 respectively.

Next, an example of pigment-based ink (pigment ink) used in the above-described image forming apparatus will be described.
Commonly used pigment-based inks are not particularly limited, but for example, the following pigments are preferably used. Moreover, you may use these pigments in mixture of multiple types.

  Examples of organic pigments include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigment, and carbon black. It is done.

  Examples of inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, and metal powder.

  The particle diameter of these pigments is preferably 0.01 to 0.30 [mu] m. If the particle diameter is 0.01 [mu] m or less, the light resistance and feathering are deteriorated because the particle diameter approaches that of the dye. On the other hand, if it is 0.30 μm or more, clogging of the discharge port or clogging with a filter in the printer occurs, and it is not possible to obtain discharge stability.

  The carbon black used in the black pigment ink is carbon black produced by the furnace method and the channel method, the primary particle size is 15 to 40 millimicrons, the specific surface area by the BET method is 50 to 300 square meters / g, The DBP oil absorption is preferably 40 to 150 ml / 100 g, the volatile content is 0.5 to 10%, and the pH value is 2 to 9. As such a thing, for example, no. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (Mitsubishi Chemical Corporation), Raven700, 5750, 5250, 5000, 3500, 1255 (Columbia), Regal400R, 330R, 660R, MoguL, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (manufactured by Cabot), color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, the same V, the same 140U, the same 140V, the special black 6, the same 5, the same 4A, the same 4 (manufactured by Degussa) and the like can be used, but are not limited thereto.

Specific examples of color pigments are listed below.
Examples of organic pigments include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigment, and carbon black. Examples of inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, and metal powder.

Specific examples according to color are as follows.
Examples of pigments that can be used for yellow ink include C.I. I. Pigment Yellow 1, 2, 2, 3, 12, 14, 16, 17, 17, 73, 74, 75, 83, 93, 95, 97, 98, 114, 128, 129, 151, 154, etc., but are not limited thereto.

  Examples of pigments that can be used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 123, 168, 184, 202, etc. However, it is not limited to these.

  Examples of pigments that can be used for cyan ink include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15:34, 16, 22, 22, 60, C.I. I. Examples thereof include, but are not limited to, Bat Blue 4 and 60.

  In addition, the pigment contained in each ink used in the present invention may be newly produced for the present invention.

  The pigments listed above can be made into an inkjet recording liquid by dispersing them in an aqueous medium using a polymer dispersant or a surfactant. As a dispersant for dispersing such organic pigment powder, a normal water-soluble resin or a water-soluble surfactant can be used.

  Specific examples of water-soluble resins include styrene, styrene derivatives, vinyl naphthalene derivatives, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itacon. Examples thereof include block copolymers consisting of at least two monomers selected from acids, itaconic acid derivatives, fumaric acid, fumaric acid derivatives, etc., random copolymers, or salts thereof. These water-soluble resins are alkali-soluble resins that are soluble in an aqueous solution in which a base is dissolved. Among them, a resin having a weight average molecular weight of 3000 to 20000 is used as a dispersion when used in an inkjet recording liquid. It is particularly preferred because of the advantages that it can be reduced in viscosity and can be easily dispersed.

  The simultaneous use of the polymer dispersant and the self-dispersing pigment is a preferable combination because an appropriate dot diameter can be obtained. The reason is not clear, but it is thought as follows.

  That is, the penetration into the recording paper is suppressed by containing the polymer dispersant. On the other hand, since the aggregation of the self-dispersing pigment is suppressed by containing the polymer dispersant, the self-dispersing pigment can smoothly spread in the lateral direction. Therefore, it is considered that the dots spread widely and thinly and ideal dots can be formed.

  Moreover, the following are mentioned as a specific example of the water-soluble surfactant which can be used as a dispersing agent. For example, anionic surfactants include higher fatty acid salts, alkyl sulfates, alkyl ether sulfates, alkyl ester sulfates, alkyl aryl ether sulfates, alkyl sulfonates, sulfosuccinates, alkyl allyls and alkyl naphthalene sulfonic acids. Examples thereof include salts, alkyl phosphates, polyoxyethylene alkyl ether phosphate esters, and alkyl allyl ether phosphates. Examples of the cationic surfactant include alkylamine salts, dialkylamine salts, tetraalkylammonium salts, benzalkonium salts, alkylpyridinium salts, imidazolinium salts, and the like. Furthermore, examples of the amphoteric surfactant include dimethylalkyl lauryl betaine, alkyl glycine, alkyl di (aminoethyl) glycine, imidazolinium betaine and the like. Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene polyoxypropylene glycol, glycerin ester, sorbitan ester, sucrose ester, glycerin ester polyoxyethylene ether, sorbitan Examples thereof include polyoxyethylene ethers of esters, polyoxyethylene ethers of sorbitol esters, fatty acid alkanolamides, polyoxyethylene fatty acid amides, amine oxides, and polyoxyethylene alkylamines.

  Further, the pigment can be provided with dispersibility by coating with a resin having a hydrophilic group and encapsulating the pigment.

  As a method for coating a water-insoluble pigment with an organic polymer and microencapsulating, all conventionally known methods can be used. Conventionally known methods include chemical production methods, physical production methods, physicochemical methods, mechanical production methods, and the like. Specifically, there are the following manufacturing methods.

Interfacial polymerization method (a method in which two types of monomers or two types of reactants are separately dissolved in a dispersed phase and a continuous phase, and both substances are reacted at the interface between them to form a wall film);

In-situ polymerization method (method of supplying a liquid or gas monomer and catalyst, or two reactive substances from either one of the continuous phase core particles to cause a reaction to form a wall film);

  ・ Liquid-cured coating method (method of forming a wall film by insolubilizing droplets of a polymer solution containing core material particles in a liquid with a curing agent);

-Coacervation (phase separation) method (a method in which a polymer dispersion in which core material particles are dispersed is separated into a coacervate (concentrated phase) and a dilute phase having a high polymer concentration to form a wall film);

・ Liquid drying method (preparing a liquid in which a core material is dispersed in a solution of a wall membrane material, placing the dispersion in a liquid in which the continuous phase of this dispersion is not miscible, and forming a composite emulsion to dissolve the wall membrane material. A method of forming a wall film by gradually removing the medium in the medium);

  Melt dispersion cooling method (using a wall film material that melts into a liquid state when heated and solidifies at room temperature, this material is heated and liquefied, the core material particles are dispersed in it, cooled to fine particles, and cooled to the wall. A method of forming a film);

・ Air suspension coating method (Method of forming a wall membrane by suspending powder core material particles in the air with a fluidized bed and suspending them in an air stream while spraying and mixing the coating solution of the wall membrane material) ;

-Spray drying method (a method in which the encapsulated stock solution is sprayed and contacted with hot air to evaporate and dry the volatile components to form a wall film);

  -Acid precipitation method (at least a part of anionic groups of organic polymer compounds containing anionic groups is neutralized with a basic compound to give solubility in water and kneaded in an aqueous medium with a colorant. Then, neutralize or acidify with an acidic compound, deposit organic compounds and fix them on the colorant, and then neutralize and disperse))

-Phase inversion emulsification method (a mixture containing an anionic organic polymer having dispersibility in water and a colorant is used as an organic solvent phase, and water is added to the organic solvent phase or And the like).

  Examples of organic polymers (resins) used as the material constituting the microcapsule wall membrane material include polyamide, polyurethane, polyester, polyurea, epoxy resin, polycarbonate, urea resin, melamine resin, phenol resin, and polysaccharide. , Gelatin, gum arabic, dextran, casein, protein, natural rubber, carboxypolymethylene, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, cellulose, ethyl cellulose, methyl cellulose, nitrocellulose, hydroxyethyl cellulose, acetic acid Cellulose, polyethylene, polystyrene, (meth) acrylic acid polymer or copolymer, (meth) acrylic acid ester polymer or copolymer, (meth) acrylic acid (Meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid copolymer, styrene-maleic acid copolymer, sodium alginate, fatty acid, paraffin, beeswax, water wax, hardened beef tallow, carnauba wax, albumin, etc. .

  Among these, organic polymers having an anionic group such as a carboxylic acid group or a sulfonic acid group can be used. Nonionic organic polymers include, for example, polyvinyl alcohol, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate or their (co) polymers, and 2-oxazoline cationic ring-opening polymers. Is mentioned. In particular, a complete saponified product of polyvinyl alcohol is particularly preferable because it has low water solubility and is easily dissolved in hot water but difficult to dissolve in cold water.

  Further, the amount of the organic polymer constituting the wall membrane material of the microcapsule is 1% by weight or more and 20% by weight or less based on the water-insoluble colorant such as an organic pigment or carbon black. By setting the amount of the organic polymer within the above range, the content of the organic polymer in the capsule is relatively low so that the pigment develops due to the organic polymer covering the pigment surface. Can be suppressed. If the amount of the organic polymer is less than 1% by weight, it is difficult to exert the effect of encapsulation. Conversely, if the amount exceeds 20% by weight, the color developability of the pigment is significantly reduced. In consideration of other characteristics, the amount of the organic polymer is preferably in the range of 5 to 10% by weight based on the water-insoluble colorant.

  That is, since a part of the color material is exposed without being substantially covered, it is possible to suppress a decrease in color developability, and conversely, a part of the color material is not substantially exposed without being exposed. Since it is coated, it is possible to simultaneously exhibit the effect that the pigment is coated. The number average molecular weight of the organic polymers used in the present invention is preferably 2000 or more from the viewpoint of capsule production. Here, “substantially exposed” means not the partial exposure associated with defects such as pinholes and cracks, but a state where it is intentionally exposed.

  Furthermore, if an organic pigment or self-dispersing carbon black, which is a self-dispersing pigment, is used as a colorant, the dispersibility of the pigment is improved even if the content of the organic polymer in the capsule is relatively low. In addition, since sufficient storage stability of the ink can be secured, it is more preferable for the present invention.

  It is preferable to select an organic polymer suitable for the microencapsulation method. For example, in the case of interfacial polymerization, polyester, polyamide, polyurethane, polyvinyl pyrrolidone, epoxy resin and the like are suitable. In the case of using the in-situ polymerization method, a polymer or copolymer of (meth) acrylic acid ester, (meth) acrylic acid- (meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid copolymer, Polyvinyl chloride, polyvinylidene chloride, polyamide and the like are suitable. In the case of the liquid curing method, sodium alginate, polyvinyl alcohol, gelatin, albumin, epoxy resin and the like are suitable. In the case of the coacervation method, gelatin, celluloses, casein and the like are suitable. In addition, in order to obtain a fine and uniform microencapsulated pigment, it is possible to use all conventionally known encapsulation methods other than those described above.

  When the phase inversion method or the acid precipitation method is selected as the microencapsulation method, anionic organic polymers are used as the organic polymers constituting the wall membrane material of the microcapsules. The phase inversion method is a composite or composite of an anionic organic polymer having self-dispersibility or solubility in water and a colorant such as a self-dispersion organic pigment or self-dispersion carbon black, or a self-dispersion method. A mixture of a colorant such as a dispersible organic pigment or self-dispersing carbon black, a curing agent, and an anionic organic polymer is used as an organic solvent phase, and water is added to the organic solvent phase, or the organic solvent is submerged in water. In this method, a solvent phase is introduced and microencapsulation is performed while self-dispersion (phase inversion emulsification) is performed. In the above phase inversion method, there is no problem even if the organic solvent phase is mixed with a recording liquid vehicle or additives. In particular, it is more preferable to mix a liquid medium of a recording liquid because a dispersion liquid for recording liquid can be directly produced.

  On the other hand, in the acid precipitation method, a part or all of the anionic group of the anionic group-containing organic polymer is neutralized with a basic compound, and a colorant such as a self-dispersing organic pigment or self-dispersing carbon black, A water-containing cake obtained by a production method comprising a step of kneading in an aqueous medium and a step of neutralizing and acidifying an acidic compound to precipitate an anionic group-containing organic polymer and fixing it to a pigment, This is a method of microencapsulation by neutralizing a part or all of an anionic group using a compound. By doing in this way, the aqueous dispersion containing the anionic microencapsulated pigment which is fine and contains many pigments can be manufactured.

  Examples of the solvent used for microencapsulation as described above include alkyl alcohols such as methanol, ethanol, propanol and butanol; aromatic hydrocarbons such as benzol, toluol and xylol; methyl acetate Esters such as ethyl acetate and butyl acetate; Chlorinated hydrocarbons such as chloroform and ethylene dichloride; Ketones such as acetone and methyl isobutyl ketone; Ethers such as tetrahydrofuran and dioxane; Cellosolves such as methyl cellosolve and butyl cellosolve Etc. The microcapsules prepared by the above method are once separated from these solvents by centrifugation or filtration, and then stirred and redispersed with water and the necessary solvent, and used for the intended present invention. To obtain a recording liquid capable of The average particle diameter of the encapsulated pigment obtained by the above method is preferably 50 nm to 180 nm.

  By coating the resin in this way, the pigment adheres firmly to the printed material, whereby the scratching property of the printed material can be improved.

In order to make the recording liquid of the present invention have desired physical properties or to prevent clogging of the nozzles of the recording head due to drying, it is preferable to use a water-soluble organic solvent in addition to the coloring material. The water-soluble organic solvent includes a wetting agent and a penetrating agent. The wetting agent is added for the purpose of preventing clogging of the nozzles of the recording head due to drying. Specific examples of the wetting agent include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, 1,3-butanediol, 1,3-propanediol, and 2-methyl-1,3-propane. Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, 1,2 Polyhydric alcohols such as 1,4-butanetriol, 1,2,3-butanetriol, and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene Polyhydric alcohol alkyl ethers such as glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether Forehead: Nitrogen-containing heterocyclic compounds such as N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam; formamide, N-methylformamide, Amides such as formamide and N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethyl And amines such as ruamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol, propylene carbonate, ethylene carbonate, and γ-butyrolactone. These solvents are used alone or in combination with water.

  Further, the penetrant is added for the purpose of improving the wettability between the recording liquid and the recording material and adjusting the penetration speed. As the penetrant, those represented by the following general formulas (I) to (IV) and (A) are preferable. That is, a polyoxyethylene alkylphenyl ether surfactant of the following formula (I), an acetylene glycol surfactant of the formula (II), a polyoxyethylene alkyl ether surfactant of the following formula (III), a formula (IV ) Polyoxyethylene polyoxypropylene alkyl ether surfactant and (A) fluorosurfactant can reduce the surface tension of the liquid, thus improving wettability and increasing penetration rate. it can.

（Ｒは分岐していても良い炭素数６〜１４の炭化水素鎖、ｋは５〜２０）

(R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, k is 5 to 20)

（ｍ、ｎは０〜４０）

(M and n are 0 to 40)

（Ｒは分岐していても良い炭素数６〜１４の炭化水素鎖、ｎは５〜２０）

(R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, n is 5 to 20)

（Ｒは炭素数６〜１４の炭化水素鎖、ｍ、ｎは２０以下の数）

(R is a hydrocarbon chain having 6 to 14 carbon atoms, m and n are numbers of 20 or less)

（ｍは、０〜１０の整数、ｎは、１〜４０の整数を表す）。

(M represents an integer of 0 to 10, and n represents an integer of 1 to 40).

  Other than the compounds of the formulas (I) to (IV) and (A), for example, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, Alkyl and aryl ethers of polyhydric alcohols such as tetraethylene glycol chlorophenyl ether, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine-based surfactants, lower alcohols such as ethanol and 2-propanol However, fluorine-based surfactants are particularly preferable.

  Examples of fluorosurfactants include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, perfluoroalkylamine oxide compounds. The structure shown by the general formula (A) is particularly preferable from the viewpoint of reliability. Further, commercially available fluorine compounds include Surflon S-111, S-112, S-113, S121, S131, S132, S-141, and S-145 (manufactured by Asahi Glass Co., Ltd.), Fullrad FC-93. , FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431, FC-4430 (manufactured by Sumitomo 3M), MegaFuck F-470, F-1405, F -474 (Dainippon Ink & Chemicals), Zonyl FS-300, FSN, FSN-100, FSO (DuPont), Ftop EF-351,352,801,802 (Gemco) etc. It can be obtained and used in the present invention. Of these, Zonyl FS-300, FSN, FSN-100, and FSO (manufactured by DuPont), which are particularly excellent in reliability and color development, can be suitably used.

  The surface tension of the recording liquid (ink) used in the image forming method according to the present invention is more preferably 35 mN / m or less.

  The viscosity of the recording liquid (ink) used in the image forming method according to the present invention is preferably 1.0 to 20.0 cP, and from the viewpoint of ejection stability, it is 3.0 to 10.0 cP. More preferably it is.

  The pH of the recording liquid (ink) used in the image forming method according to the present invention is preferably 3 to 11, and 6 to 10 from the viewpoint of preventing corrosion of the metal member in contact with the liquid. Further preferred.

  The recording liquid can contain an antiseptic / antifungal agent. By containing an antiseptic / antifungal agent, the growth of bacteria can be suppressed, and the storage stability and image quality stability can be improved. As antiseptic / antifungal agents, benzotriazole, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, isothiazoline compounds, sodium benzoate, sodium pentachlorophenol, and the like can be used.

  Further, the recording liquid can contain a rust inhibitor. By containing a rust preventive agent, a coating can be formed on the metal surface in contact with the liquid, such as a head, and corrosion can be prevented. As the rust inhibitor, for example, acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like can be used.

  Further, the recording liquid can contain an antioxidant. By containing an antioxidant, even when radical species that cause corrosion are generated, the antioxidant can be prevented by eliminating the radical species.

  Typical examples of the antioxidant include phenolic compounds and amine compounds. Examples of the phenolic compounds include hydroquinone and gallate compounds, 2,6-di-tert-butyl-p-cresol, and stearyl. -Β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl- 6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-4-hydroxybenzyl) benzene, Hindered materials such as lith (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, tetrakis [methylene-3 (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionate] methane Phenol compounds are exemplified, and amine compounds include N, N′-diphenyl-p-phenylenediamine, phenyl-β-naphthylamine, phenyl-α-naphthylamine, N, N′-β-naphthyl-p-phenylene. Examples include diamine, N, N′-diphenylethylenediamine, phenothiazine, N, N′-di-sec-butyl-p-phenylenediamine, 4,4′-tetramethyl-diaminodiphenylmethane, and the like.

  Further, as the latter, sulfur compounds and phosphorus compounds are representative, but as sulfur compounds, dilauryl thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dithiol. Examples include myristyl thiodipropionate, distearyl β, β′-thiodibutyrate, 2-mercaptobenzimidazole, dilauryl sulfide and the like, and phosphorus compounds include triphenyl phosphite, trioctadecyl phosphite, tridecyl. Examples include phosphite, trilauryl trithiophosphite, diphenylisodecyl phosphite, trinonylphenyl phosphite, distearyl pentaerythritol phosphite.

  The recording liquid can contain a pH adjusting agent. Examples of the pH adjuster include hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, lithium carbonate, Examples include alkali metal carbonates such as sodium carbonate and potassium carbonate, amines such as diethanolamine and triethanolamine, boric acid, hydrochloric acid, nitric acid, sulfuric acid, and acetic acid.

Specific examples of ink will be described below, but the present invention is not limited to this.
<Black ink>
Using a carbon black dispersion made of Cabot (sulfon group addition type self-dispersion type), the mixture was stirred with the following formulation, and then filtered through a 0.8 μm polypropylene filter to prepare an ink.
40 parts by weight of black dispersion
CAB-O-JET 200 (Sulfon group added type Cabot)
Acrylic silicone resin emulsion 8 parts by weight Nanocrill SBCX-2821 (Toyo Ink)
1,3-butanediol 18 parts by weight Glycerin 9 parts by weight
2-pyrrolidone 2 parts by weight Ethylhexanediol 2 parts by weight Fluorosurfactant FS-300 (manufactured by Du Pont) 2 parts by weight General formula (A) m = 6-8 n = 26 or more Proxel LV (manufactured by Avicia) ) 0.2 parts by weight Ion exchange water 20.8 parts by weight

<Color ink>
A copper phthalocyanine pigment-containing polymer fine particle dispersion was additionally prepared with reference to Preparation Example 3 of JP-A No. 2001-139849.
First, in preparing a polymer solution, the inside of a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas introduction tube, reflux tube and dropping funnel was sufficiently replaced with nitrogen gas, and then 11.2 g of styrene, acrylic acid 2.8 g, 12.0 g of lauryl methacrylate, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) and 0.4 g of mercaptoethanol were added and the temperature was raised to 65 ° C. Warm up. Next, styrene 100.8 g, acrylic acid 25.2 g, lauryl methacrylate 108.0 g, polyethylene glycol methacrylate 36.0 g, hydroxyethyl methacrylate 60.0 g, styrene macromer (manufactured by Toagosei Co., Ltd., trade name: AS-6) A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobisdimethylvaleronitrile 2.4 g and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours. After completion of dropping, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobisdimethylvaleronitrile was added, and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution having a concentration of 50%.

  28 g of the polymer solution obtained above, 26 g of copper phthalocyanine pigment, 13.6 g of 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone and 30 g of ion-exchanged water were sufficiently stirred. Thereafter, the mixture was kneaded 20 times using a three-roll mill (manufactured by Noritake Co., Ltd., trade name: NR-84A). The obtained paste was put into 200 g of ion-exchanged water and sufficiently stirred, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain 160 g of a cyan polymer fine particle dispersion having a solid content of 20.0 wt%. .

  This dispersion was mixed and stirred with the following formulation, and then filtered through a 0.8 μm polypropylene filter to prepare an ink.

Cyan polymer fine particle dispersion 45 parts by weight
1,3-butanediol 21 parts by weight Glycerin 8 parts by weight Ethylhexanediol 2 parts by weight Fluorosurfactant FSN-100 (manufactured by Du Pont) 1 part by weight General formula (A) m = 1 to 9 n = 0 ~twenty five
Proxel LV (manufactured by Avicia) 0.5 parts by weight Ion-exchanged water 23.5 parts by weight

Next, refer to FIG. 9 and subsequent drawings regarding the image processing apparatus loaded with the program according to the present invention for causing a computer to execute the image forming method according to the present invention for outputting a print image by the image forming apparatus and the image forming apparatus. To explain.
This printing system (image forming system) is configured by connecting one or a plurality of image processing apparatuses 400 including a personal computer (PC) or the like and an inkjet printer 500 via a predetermined interface or network.

  As shown in FIG. 10, in the image processing apparatus 400, a CPU 401 and various ROMs 402 and RAM 403, which are memory means, are connected by a bus line. The bus line is connected to a storage device 406 using a magnetic storage device such as a hard disk, an input device 404 such as a mouse and a keyboard, a monitor 405 such as an LCD or a CRT, and the like via a predetermined interface. A storage medium reading device for reading a storage medium such as an optical disk is connected, and a predetermined interface (external I / F) 407 for communicating with a network such as the Internet or an external device such as a USB is connected.

  An image processing program including a program according to the present invention is stored in the storage device 406 of the image processing apparatus 400. This image processing program is installed in the storage device 406 by being read from a storage medium by a storage medium reader or downloaded from a network such as the Internet. With this installation, the image processing apparatus 400 becomes operable to perform the following image processing. Note that this image processing program may operate on a predetermined OS. Further, it may be a part of specific application software.

Here, an example in which the image processing method according to the present invention is executed by the program on the image processing apparatus 400 side will be described with reference to the functional block diagram of FIG.
A printer driver 411, which is a program according to the present invention on the image processing apparatus 400 (PC) side, transfers image data 410 given from application software or the like from a color space for monitor display to a color space for a recording apparatus (image forming apparatus). CMM (Color Management Module) processing unit 412 that performs conversion to RGB (RGB color system → CMY color system), BG / UCR (black generation / Under Color Removal) process that performs black generation / under color removal from CMY values Unit 413, a total amount regulating unit 414 that corrects the CMYK signal according to the maximum total amount of recording color materials that can be image-formed by the image forming apparatus with respect to the CMYK signal serving as a recording control signal, and reflects the characteristics of the recording apparatus and user preferences A γ correction unit 415 that performs input / output correction, a zooming process that performs an enlargement process in accordance with the resolution of the image forming apparatus (not shown), A halftone processing unit (multivalue / low value matrix) 416 including a multi-value / low-value matrix that replaces image data with a pattern arrangement of dots ejected from the image forming apparatus, dots that are print image data obtained by the half-tone processing A rasterizing unit 417 that divides the pattern data into data for each scan and further develops the data in accordance with each nozzle position to be recorded is sent to the inkjet printer 500 as an output 418 of the rasterizing unit 417.

A part of such image processing can also be executed on the ink jet printer 500 side. This example will be described with reference to the functional block diagram of FIG.
The printer driver 421 on the image processing apparatus 400 (PC) side sends the image data generated by performing the processing up to the above-described γ correction to the inkjet printer 500.

  On the other hand, a printer controller 511 (control unit 200) of the inkjet printer 500 includes a zooming unit that performs enlargement processing according to the resolution of the image forming apparatus (not shown), and a dot pattern arrangement that ejects image data from the image forming apparatus. The halftone processing unit (multivalue / small value matrix) 416 including the multivalue / small value matrix (dither mask) to be replaced with the dot pattern data of the print image data obtained by the halftone processing is divided into data for each scan. Further, a rasterizing unit 417 for developing data in accordance with each nozzle position for recording is provided, and the output of the rasterizing unit 517 is given to the print control unit 207.

  The image processing method according to the present invention can be suitably applied to any of the configurations shown in FIGS. Here, as in the configuration shown in FIG. 11, an example will be described in which the ink jet recording apparatus does not have a function of generating a dot pattern to be actually recorded upon receiving an image drawing or character print command in the apparatus. That is, a print command from application software executed by the image processing apparatus 400 serving as a host is subjected to image processing by a printer driver 411 incorporated as software in the image processing apparatus 400 (host computer) and output from the inkjet printer 500. An example will be described in which possible multi-value dot pattern data (print image data) is generated, rasterized, transferred to the ink jet printer 500, and the ink jet printer 500 is printed out.

  Specifically, in the image processing apparatus 400, an image drawing or character recording command from an application or operating system (for example, a description of the position and thickness and shape of a line to be recorded, a typeface of a character to be recorded, and the like) (Which describes the size, position, etc.) is temporarily stored in the drawing data memory. Note that these instructions are written in a specific print language.

  The command stored in the drawing data memory is interpreted by the rasterizer, and if it is a line recording command, it is converted into a recording dot pattern according to the designated position and thickness, etc. If there is image data, the outline information of the corresponding character is called from the font outline data stored in the image processing apparatus (host computer) 400 and converted into a recording dot pattern corresponding to the designated position and size. This is converted into a recording dot pattern as it is.

  Thereafter, image processing is performed on these recorded dot patterns (image data 410) and stored in the raster data memory. At this time, the image processing apparatus 400 rasterizes the recording dot pattern data with the orthogonal grid as the basic recording position. As described above, as image processing, for example, color management processing (CMM) for adjusting color, γ correction processing, halftone processing such as dither method and error diffusion method, background removal processing, and total ink amount restriction processing and so on. The recording dot pattern stored in the raster data memory is transferred to the ink jet recording apparatus 500 via the interface.

Therefore, an image processing method according to the present invention will be described. In addition,
First, a method of reproducing black by using a color other than black ink or reproducing black by mixing color ink other than black ink with black ink will be described. As described above, in inkjet recording, when four colors of cyan (C), magenta (M), yellow (Y), and black (K) or higher image quality is required, a density called photo ink is used. Color reproduction is performed with 6 to 7 colors using low inks such as photocyan (PC) and photomagenta (PM).

  Black ink is basically used for reproduction of black, but by combining cyan dots, magenta dots, and yellow dots (these are also referred to as “CMY dots”), black can be reproduced in a pseudo manner. Is possible. This is due to the characteristic of the subtractive color mixing method in which the brightness and saturation decrease each time colors are superimposed.

  In the following, the black reproduced using a combination of CMY dots (using CMY inks) is referred to as “composite black”, and the black reproduced using only black ink is referred to as “real black” and black ink. Black that is reproduced with four colors by adding CMY is called "four-color mixed black". In the figure used for explanation, as shown in FIG. 13, CMY color inks are required surface types, K is a blacked surface type, and composite black is a surface type for distinguishing dots of each color. In the combined face types, the four-color mixed black is indicated by the face type in which spur-like protrusions are added to the outer periphery of the black paint, but these notations do not indicate the shape or density of the dots.

  As shown in FIG. 14, composite black is formed by combining CMY dots, but changes to bluish black or reddish black depending on the overlapping state of CMY dots. Become. This is because composite black dots (hereinafter referred to as “3K dots”) generated by overlapping CMY three-color dots have an adverse effect on image quality as undesirable turbidity in color reproduction. This is because the dot arrangement is intentionally shifted in order to prevent the graininess from being deteriorated by mixing 3K dots (including black dots) that are more noticeable than CMY dots.

  Specifically, as shown in FIG. 15, the dot arrangement pattern is adjusted so that 3K dots are less likely to be generated in the CMY halftone processing. In FIG. 15, the overlap of dots at a low gradation level is avoided as much as possible by changing the coordinates at which a single dot generation pattern (Bayer-type dither processing) is applied for each color. In addition, methods such as rotating a generated pattern and applying a completely different generated pattern are also often used.

  In addition, in the case of error diffusion processing, the dot arrangement pattern generated even with a difference of only one pixel is completely different. Therefore, it is possible to suppress the generation of 3K dots to some extent by adding processing such as random noise superimposition. .

  Furthermore, even if the input data “R = G = B” is not necessarily converted data “C = M = Y” by the above-described CMM or γ correction, the unit area actually generated is not necessarily obtained. The number of dots per hit may vary from color to color, and this imbalance in the number of dots also contributes to a decrease in image quality due to fluctuations in gray balance.

  When gray balance variation is not allowed as in the case of a monochrome image, gradation is normally reproduced only by real black. In this case, in the nozzles of the color recording head, the ink near the nozzles is dried and clogging is likely to occur. In order to prevent this clogging, frequent maintenance is required. The maintenance operation has an influence on the recording speed, and the ink consumption by the maintenance has an influence on the recording cost.

  Therefore, in the image processing method according to the present invention, when the input image is black, an image is formed with black ink, and image data for using the color ink for the image is generated. That is, as shown in FIG. 16, when the input image is black, an image is formed with black ink, and at least one color ink is used for this, thereby clogging the nozzles of the color recording head. To prevent. In the example of FIG. 16, by using all of CMY, composite black is used to suppress coloring of black dots when color ink is used.

  In this case, two or more colors including K ink and at least one color ink are used for black image formation, and the K ink usage amount per unit area is recorded using a single K ink color and the same density image is recorded. The amount of ink used for each color other than K per unit area is set to 5 to 35% when an image of the same density is recorded using a single K ink, and K ink and Color ink dots are formed at the same position. By setting the usage amount of the K ink and the color ink in such a quantitative range, coloring of the black image can be suppressed.

  In addition, when two or more colors including K ink and at least one color ink are used for black image formation, the total ink amount per unit area is K ink single color, and the same density is recorded from 80 to 80. The amount of ink is 130%, and the dots of K ink and color ink are formed at the same position. By defining the amounts of the K ink and the color ink in such a quantitative range, coloring of the black image can be suppressed.

  In addition, the density error is ± 10% when two or more colors including K ink and at least one color ink are used for black image formation, and an image of the same density is recorded using a single K ink. In addition, dots of K ink and color ink are formed at the same position. By defining the density in the case of forming with K ink and color ink within such an error range, coloring of the black image can be suppressed.

  Further, in addition to these, it is possible to arrange dots of colors other than K with a gradation of 90% or more at half or more of positions where K dots are arranged.

An example of these will be described with reference to FIG.
In FIG. 17, (a) shows an example of 100% black, (b) shows an example of 75% black, and (c) shows an example of 50% black.

  Here, at the time of real black, the dots are all arranged in the 100% black example and the ink use amount is the maximum Kmax, and in the 75% black example, the dots are arranged at 3/4 and the ink use amount is the maximum Kmax · 3 / In the example of 50% black, the dots are arranged in 1/2, and the ink usage is maximum Kmax · 1/2.

  In contrast, in the case of four-color mixed black, the dot arrangement is the same as in the case of real black, but in the example of 100% black, the CMY ink usage is Kmax · 15%, and the K ink usage is Kmax · 90%, and the total ink usage is Kmax · 135%. Similarly, in the 75% black example, the CMY ink usage is Kmax · 10%, the K ink usage is Kmax · 80%, and the total ink usage is Kmax · 115%. In the example of 50% black, the ink usage of CMY is Kmax · 10%, the ink usage of K is Kmax · 70%, and the total ink usage is Kmax · 100%.

  In this example, since CMYK is formed only by overlapping dots, the expressed black is always fixed to the hue of the composite black dot, and the gray balance does not fluctuate for each gradation level. As described above, in the case of a black image in a color image, since it is actually data that has undergone CMM or γ correction, CMYK primary color dots or RGB colors do not overlap with CMYK. In some cases, secondary color dots may be mixed, but since the data is originally “R = G = B”, the mixing ratio is very small and does not affect the black hue.

  Thus, when reproducing black, when mixing black ink and colors other than black ink and forming an image on a recording medium, two or more colors including K ink are used for black image formation, and the unit area The amount of K ink used per unit area is 20 to 100% when the same density is recorded using a single K ink, and the amount of ink used for each color other than K per unit area is the same density using a single K ink. Per unit area using a configuration in which dots of each color including K are formed at the same position, or two or more colors including K ink are used for black image formation. The total ink amount is set to 80 to 130% of the case where K ink single color is used and the same density is recorded, and the dot of each color including K is formed at the same position, or K ink is used for black image formation. Use two or more colors including, K ink An error of density when recording the same density using colors is ± 10%, and a configuration in which dots of each color including K are formed at the same position (a configuration for generating such image data). As a result, it is possible to reduce the occurrence of color unevenness due to dot distribution deviation, and to achieve a uniform color tone with an ink usage of 130% or less of the ink usage when reproducing black with only black ink. It is possible to reproduce black, and using color ink together with black image formation provides the same effect as color ink, but the nozzles for color ink are clogged. Can be prevented.

  In addition, depending on how to take the ink adhesion amount (usage amount) of black ink and inks other than black ink (color ink), the ink adhesion amount (usage amount) can be made equivalent to the case of black ink single color, In this case, clogging or the like can be prevented without increasing the cost of the ink.

  In the image processing method of the present invention, it is preferable to change the dot arrangement method according to the difference in the black image ratio. For example, as shown in FIG. 18, the ratio of the black image to the entire image differs depending on the color character mode (color image / monochrome image always exists), the monochrome photo mode, and the color photo mode. That is, in the color character mode (mode including color characters), the average gradation is 70%, the color image ratio is 20%, and the black image ratio is 80%. The ratio is 0% and the black image ratio is 100%. In the color photo mode, the average gradation is 50%, the color image ratio is 70%, and the black image ratio is 30%.

  Accordingly, the dot arrangement method (the number of dots in this case) is varied as shown in FIG. 19 corresponding to the black image ratio in each mode. In FIG. 19, (a) is an example of a color character mode (gradation 25%), (b) is an example of a monochrome photography mode (gradation 25%), and (c) is a color photograph. An example of the mode (gradation 25%) is shown.

  In this case, at the time of real black, 4 dots are arranged in any of the color character mode, the monochrome photo mode, and the color photo mode, and the ink use amount is Kmax · ¼.

  On the other hand, at the time of four-color mixed black, in the color character mode, 3 dots are arranged for CMY, the ink usage of CMY is Kmax · ¼ · 7.5%, and 4 dots are arranged for K, and the K ink usage is Kmax · 1/4 point is 65%, and the total ink usage is Kmax · 1/4 · 87.5%.

  On the other hand, in the monochrome photo mode, 4 dots are arranged for CMY, and the ink usage of CMY is Kmax · 1/4 · 10%, and 4 dots are arranged for K and the K ink usage is Kmax · 1 / The total amount of ink used is Kmax · ¼ · 90%. In other words, in the monochrome photo mode in which the black image ratio is higher (100%) than the color character mode and the entire surface is a black image, the color recording head is likely to be clogged because color ink is not used. By relatively increasing the use ratio of the color dots, it is possible to prevent the nozzles of the color recording head from being dried.

  In the color photo mode, 2 dots are arranged for CMY, the ink usage of CMY is Kmax · 1/4 · 5%, 4 dots are arranged for K, and the K ink usage is Kmax · 1/4 point 70. %, And the total ink usage is Kmax · 1/4 · 85%. In other words, in the color photo mode in which the black image ratio is low and the color image ratio is high compared to the color character mode, the usage rate of the black ink is reduced and the black recording head is likely to be clogged. By increasing the usage amount of the black nozzle, it is possible to prevent the nozzle of the black recording head from being dried.

  As described above, since the effect obtained by the present invention varies depending on the type of image, either or both of the ink usage amount and the dot formation position of each color are switched for each print mode, and the object of the input image data is changed. In response to this, either or both of the ink usage amount and the dot formation position of each color are switched, and the dots of colors other than K with a gradation of 90% or more are set to 1/2 or more of the positions where K dots are arranged. By arranging the dots, it is possible to always prevent clogging of the nozzles.

  In addition, nozzle clogging can always be prevented by switching either or both of the ink usage amount and the dot formation position of each color according to the black image usage ratio.

  As described above, the image data is processed for each color by the CMM processing unit, the γ correction unit, and the halftone processing unit. In the present invention, the quality of the black image is determined by the CMY dot arrangement method. Therefore, the process of making the arrangement position and the dot size of dots of colors other than K the same, and the process of arranging dots using the same dither mask (synonymous with dither matrix) for each color are performed. Thus, the data processing load can be reduced while preventing the nozzles from drying.

  In addition, it may be undesirable to make the dot formation positions of the respective colors the same. For example, in a highlight gradation close to a white background, a mixed dot of black and color is very conspicuous and becomes a factor of deteriorating the graininess. Therefore, in a photographic image, the graininess can be improved by not performing the process of making the dot positions the same at a gradation level that is very close to a white background. When the granularity is more important than the uniformity of the black color tone in recording color photographs, etc., whether or not the dot formation positions for each color are the same when reproducing black according to external instructions By doing so, it is possible to obtain a good image while preventing the nozzle from drying.

Next, the flow of the image processing method according to the present invention will be described with reference to FIGS.
First, with reference to FIG. 20 showing the flow of image processing in the prior art, a case will be described in which processing for making the CMYK dot formation positions the same is not performed. In this case, CMM processing or the like is performed on the input data to convert it into cyan (C), magenta (M), yellow (Y), and black (K), and γ correction is performed for each of C, M, Y, and K. After performing halftone processing for each of C, M, Y, and K, output data is output. For this reason, it is necessary to perform separate halftone processing for each of C, M, Y, and K, which increases the load on the memory and the load on the data processing.

  Next, an example of the flow of image processing according to the present invention will be described with reference to FIG. 21 in which a dither method is used for halftone processing and processing for making the dot formation positions of the respective colors the same is performed. In the dither method, the dots are reproduced in the arrangement specified by the threshold matrix, so by using a dither mask common to CMYK, each dot formation position can be made the same, and four colors are automatically mixed. Black dots (dots with overlapping CMYK) are generated. That is, in this case, CMM processing or the like is performed on the input data to convert it into cyan (C), magenta (M), yellow (Y), and black (K), and for each of C, M, Y, and K. After performing γ correction, halftone processing using a dither matrix common to C, M, Y, and K is performed, and then output data is output.

  Next, another example of the flow of image processing according to the present invention will be described with reference to FIG. 22 and processing for using the error diffusion method for halftone processing and making the dot formation positions of the respective colors the same. In the case of error diffusion, only one pixel of noise is mixed, resulting in a different dot arrangement pattern to be formed. Therefore, in this case, for example, magenta (M) data is processed as a representative value and copied to cyan (C), yellow (Y), and black (K), thereby matching the dot positions. ing. As for black, the dot arrangement pattern formed by another process is combined with the black dot arrangement pattern processed by the magenta data, thereby increasing the ratio to the color. The process shown in FIG. 22 can be applied not only to the error diffusion method but also to the above-described dither method.

  That is, in this case, the input data is subjected to CMM processing and converted to magenta (M) (C and Y are omitted), γ correction is performed on M, and halftone processing is performed on M. C, M, Y, and K data are generated by copying to each color, K is subjected to γ correction by the Kγ correction unit, K is subjected to halftone processing by the halftone processing unit, and then processed for M described above. It is combined with K data copied as K data. The generated C, M, Y, and K data are output.

Next, the above-described image processing according to the present invention will be described with reference to the flowchart of FIG.
First, for input image data, it is determined whether or not the input is R = G = B. If the input is not R = G = B (if it is color), the first halftone process (indicated as halftone process 1). )I do. In the halftone process 1, each color of CMYK is processed by a separate halftone process as in the process described with reference to FIG.

  On the other hand, if the input image is a monochrome image or a black image of R = G = B in a color image, a second halftone process (denoted as halftone process 2) is performed. This second halftone process is a halftone process for forming four-color mixed dots, as described with reference to FIG. 21 or FIG.

  Specifically, if the input is a monochrome image or a black image of R = G = B in a color image, it is determined whether or not it is a character image, and if it is not a character image, the switching level KL = V1 is set. If there is a photo image, it is determined whether or not it is a photographic image. If it is not a photographic image, the switching level K = V2, and if it is a photographic image, the switching level LK = V3 is set, and then CMM processing and γ correction processing are performed. Note that the switching level KL is a constant and corresponds to the determination result based on the black image usage ratio (the level is independent for each image type). Using this switching level KL, at least one of the ink usage of each color and the dot formation position is switched.

  Then, it is determined whether or not the input value (RGB) is larger than LK (RGB> LK). If (RGB> LK), the second halftone process is performed, and if not (RGB> LK), the first is performed. Perform halftone processing and output.

  C, M, Y, and K inks are all pigment-based inks, black inks are pigment inks, CMY inks are dye inks, or black inks are prepared for plain paper. The same effect can be obtained in any case such as a combination in which each ink of CMY is an ink prepared for dedicated paper (including glossy paper).

  Further, as described above, since the image processing method according to the present invention is more effective to switch the conditions by the combination of the ink composition and the specific paper, when this combination is known in advance, Alternatively, when it is determined that the application of the image processing according to the present invention is effective by the paper type determination unit that determines the type of the paper loaded in the image forming apparatus, the switching may be performed automatically. it can. In other words, in conjunction with the recording mode determined according to the type of recording medium and the recording method, the optimum image processing is applied when reproducing black, and the user has to bother selecting it. Can be omitted.

  In addition, the user's tastes vary widely, and there are cases in which some users desire normal composite black instead of image processing according to the present invention. Therefore, not only forcibly and automatically executing the image processing according to the present invention, but also providing means for enabling ON / OFF switching according to the user's designation makes it possible to meet a wide range of needs.

  The means for enabling ON / OFF switching according to the user's designation, that is, the means for switching whether or not to perform image processing according to the present invention in response to an instruction from the outside is provided on the image forming apparatus side, for example, If the host side (information processing device or image processing device side) can be provided on the operation unit, the user can select it on the print mode setting screen by the printer driver. Can do.

  Further, in the above-described image processing method, for example, as shown in FIG. 11, all may be processed on a computer as a program (printer driver), or a part of the program may be programmed as shown in FIG. May be processed on a computer, and the rest may be converted into hardware and processed on the image forming apparatus side. Alternatively, all processing can be implemented as hardware and performed on the image forming apparatus side.

  In the embodiment described above, an example in which CMY ink is used together with K ink for a black image has been described. However, one color ink may be used. If droplets of multiple droplet sizes can be ejected, the color ink always ejects droplets of a relatively small size relative to the black ink (however, the same is true when the black ink is the minimum size). The nozzle can also be prevented from clogging.

Next, processing for performing jaggy correction for correcting a step-like change portion of a character when reproducing black characters excluding gray in the image processing according to the present invention described above will be described with reference to FIG.
Here, data in which jaggy correction processing is performed on black character input data in parallel with the processing for generating four-color mixed black, and the processed data is synthesized to combine the processed data. Is generated. By outputting such data, it is possible to improve character quality while ensuring ejection stability.

  In this case, in the jaggy correction pattern, dots may be formed with real black (only K ink), or dots may be formed with four-color mixed black. Further, the jaggy correction pattern for the four-color mixed black can be the same pattern as the jaggy correction pattern for the single-color character, or a jaggy correction pattern for the four-color mixed black character can be separately provided. By properly using the jaggy correction pattern for the single-color character and the four-color mixed black character, it is possible to suppress the difference between the color of the contour and the character portion, where the contour of the pattern of the single-color character is emphasized.

Next, the bolding process for thickening the four-color mixed black characters will be described with reference to FIG.
By making the jaggy correction pattern portion of the process for performing jaggy correction on the above-described four-color mixed black a thick pattern (bold pattern), data obtained by performing the bold process on the four-color mixed black character is generated. By performing the bolding process, it is possible to improve the character visibility even when the density is lower than that of the K ink single color.

  In this case, as the thickening pattern, dots may be formed with real black (only K ink), or dots may be formed with four-color mixed black. In addition, the fattening pattern for the four-color mixed black character can be the same pattern as the thickening pattern for the single-color character, or a fattening pattern for the four-color mixed black character can be separately provided.

  In addition, it is possible to allow the user to set or instruct from the outside whether or not to perform the bolding process (ON / OFF). Further, whether or not to perform the bolding process (ON / OFF) can be switched depending on the character size. For example, if the character size is 6 points or less, the bolding process causes the character visibility to deteriorate due to ink bleeding, so the bolding process is not performed. In this case, the user can set or instruct the switching size (character size serving as a threshold).

Next, with reference to FIG. 26, a process for thickening four-color mixed black characters and performing bold jaggy correction (thickening jaggy correction) for performing jaggy correction will be described.
Here, the jaggy correction pattern in the above-described processing for performing jaggy correction on the four-color mixed black is a fattened jaggy correction pattern that thickens the character and performs jaggy correction, thereby thickening the four-color mixed black character. Data with correction processing is generated. By performing thickening and jaggy correction, it is possible to improve character quality and improve character visibility.

  In this case, in the thickening jaggy correction pattern, dots may be formed with real black (only K ink), or dots may be formed with four-color mixed black. Further, the thickening jaggy correction pattern for the four-color mixed black can be the same pattern as the thickening pattern for the single-color character, or a thickening jaggy correction pattern for the four-color mixed black character can be separately provided.

  It is also possible to allow the user to set or instruct from the outside whether or not to perform bolding jaggy correction processing (ON / OFF). Further, whether or not to perform bolding jaggy correction processing (ON / OFF) can be switched depending on the character size. As described above, for a character having a character size of 6 points or less, the bolding process reduces the character visibility due to ink bleeding, so the bolding process is not performed. In this case, the switching size can be set or instructed by the user.

Accordingly, image processing in the case of performing the above-described jaggy correction processing, bolding processing, and bolding jaggy correction (thickening jaggy correction) processing will be described with reference to the flowchart of FIG.
First, when there is input data, a process for generating image data of four-color mixed black characters is performed on the input data as described above.

  At the same time, it is determined whether or not to perform fattening jaggy correction processing (whether it is ON or OFF). At this time, if the fattening jaggy correction process is OFF, a normal jaggy correction process is performed to generate a jaggy correction pattern. On the other hand, if the fattening jaggy correction process is ON, it is determined whether or not the character size is a predetermined size or less (for example, 6 points or less as described above). If the character size is equal to or smaller than the predetermined size, it is not preferable to perform the bolding process. Therefore, a normal jaggy correction process is performed to generate a jaggy correction pattern. On the other hand, if the character size exceeds a predetermined size, a jaggy correction pattern accompanied by a bolding process is generated by performing a thickening jaggy correction process.

  Thereafter, the four-color mixed black character pattern and the obtained jaggy correction pattern are combined (combined) to obtain output data of the image.

  Here, the amount of ink used when the above-described jaggy correction process is performed will be described with reference to FIG. Where black characters are reproduced with a single color of K ink, the total amount of ink used can be reduced to the same level or lower by reducing the amount of K ink used in four-color mixed black. That is, the above-described jaggy correction and bolding process can improve character quality and character visibility without increasing the amount of ink used.

Next, specific processing of the above-described jaggy correction processing, bolding processing, and thickening jaggy correction processing will be described with reference to FIG. Note that the notation described in FIG. 13 is not used for the notation of dots used in FIG. 29 and the subsequent drawings, and the description will be made using only image dots (filled) and blank dots (outlined).
As a method of adding large droplets (or medium droplets or small droplets) beside or below the dots forming the characters, such as jaggy correction, it is excellent in that pattern matching can be processed at high speed.

  FIG. 29A shows an example of a window used for pattern matching. The window size is a size of horizontal m and vertical n (m × n). Here, m and n have the same value, and as shown in FIG. 29 (b), an example will be described in which m = 3 and n = 3.

  Character font data is expanded into bitmap data by printer driver software. Bitmap data indicates the dots forming the font. For bit map data as font data, each bit is subjected to pattern matching in the aforementioned window unit.

Therefore, the pattern matching process will be described with reference to FIG.
First, the target pixel is set at the head of the font data. Bitmap data of font data corresponding to the window is acquired with the pixel of interest at the center. In this case, the acquired bitmap data is 3 × 3 data for 9 dots. By pattern matching, the acquired data is compared with the data of a pattern (hereinafter referred to as “reference pattern”) to which an image dot set in advance is set. ) Is replaced with image dot data.

  In these processes, one pixel may be handled as 1-byte data or 1-bit data. When handling as 1-byte data, 9 bytes are required to represent 9-dot data, whereas when handling as 1-bit data, 2-byte data is required to represent 9-dot data. Since the amount is sufficient, it is preferable to handle the data as 1-bit data because the number of data to be processed is small, the memory can be saved, and the processing speed can be improved.

An example of this pattern matching will be specifically described with reference to FIGS.
FIGS. 31A to 31C show examples of reference patterns. When pattern matching is performed with the font data shown in FIG. 32A using this reference pattern, as shown in FIG. 32A, the pixel position (dot position) D45 of the font data is used as the target pixel. Since the state of the dots included in the window W matches the reference pattern in FIG. 31C, the pixel of interest D45 is replaced from blank data to image dot data as shown in FIG. .

  Similarly, when the window W moves to the right and the target pixel becomes D46, it matches the reference pattern in FIG. 31B, so that the target pixel D46 is replaced with the image dot data from the blank data. Further, when the window W further moves to the right and the target pixel becomes D47, it matches the reference pattern of FIG. 31A, so that the target pixel D47 is replaced from blank data to image dot data. .

  In the generation of image dot data, when the original font data is represented by 0 (blank) and 255 (print data) as the bitmap data, “0” indicating blank data is displayed as the image dot data. It is changed to “255” indicating dot data. In addition, when represented by binary values such as 0 (blank) and 1 (print data), “0” indicating blank data is changed to “1” indicating print data.

  Font data composed of data indicating large droplets generated by pattern matching (in the former case), or binary (0, 1) data for small droplets and original binary (0, 1) font data (in the latter case) ), Printing large droplets (or medium or small droplets) makes it possible to realize thick characters.

  In the above specific example, an example is described in which large dots are added in the sub-scanning direction, but medium (or small) dots are added in the sub-scanning direction, and in the main scanning direction. When adding large droplets of dots, the sub-scanning direction and the main-scanning direction are separately created as reference patterns, and pattern matching is performed in the same manner, thereby increasing the size in the main-scanning direction and the sub-scanning direction. Different types of image dots can be added (replaced).

Next, a method for performing bolding processing (thickening processing) by jaggy correction will be described.
As described above, pattern matching can be processed at a high speed as a method of adding a small droplet, a medium droplet, or a large droplet to the side of or below a dot forming a character. As described above, the window size is a size of horizontal m and vertical n (m × n), but here, jaggy correction is performed on a diagonal line close to a line parallel to the main scanning direction and parallel to the sub-scanning direction. Since the jaggy correction is not performed on the oblique line close to the straight line, m and n have different values. That is, m is large so that a diagonal staircase change point close to the horizontal line and a blank dot in the vicinity thereof can be detected, and conversely, it is not necessary to detect the vicinity of the diagonal staircase change point close to the vertical line. Small value. Here, this is performed using a window with m = 9 and n = 3.

  The processing in this case will be described with reference to FIG. 33. When the pixel of interest is blank data, bitmap data of font data corresponding to the window is acquired centering on the pixel of interest. Therefore, the acquired bitmap data is 9 × 3 27 dot data. By pattern matching, the acquired data is compared with data of a reference pattern to which a small droplet set in advance is added or replaced, and when there is a match, the pixel of interest is replaced with data indicating a small droplet.

  In these processes, one pixel may be handled as 1-byte data or 1-bit data. When handling as 1-byte data, 27 bytes are required to represent 27-dot data, whereas when handling as 1-bit data, 4-byte data is required to represent 27-dot data. Since the amount is sufficient, it is preferable to handle the data as 1-bit data because the number of data to be processed is small, the memory can be saved, and the processing speed can be improved.

  An example of pattern matching in this case will be specifically described with reference to FIGS. When pattern matching is performed with the pattern shown in FIG. 35 using the reference patterns shown in FIGS. 34A to 34E, as shown in FIG. 35A, when the dot D45 of the font data is the target pixel, Since the patterns of the two dots match, as shown in FIG. 35B, the position of the pixel of interest D45 is replaced from a blank dot to a small droplet image dot.

  Also in this case, as described above, in the generation of small droplet data, the data indicating the small droplet is when the original font data is represented by 0 (blank) and 255 (print data) like bitmap data. , Or 0 (blank), 1 (print data), and binary data, and once converted to 0 (blank) and 255 (print data), the blank data and the data forming the font It may be replaced with data representing small drops (eg 85 each). When processing with 0 and 1 as it is, another memory (small droplet data memory) having the same size as the font data is provided, and “1” representing the print data is generated at the position where the small droplet is placed. . Font data composed of data indicating small drops and large drops generated by pattern matching (in the former case), or binary (0, 1) data for small drops and original binary (0, 1) font data In the latter case, bold characters can be realized by printing small droplets and large droplets.

  In this way, by using a 9 × 3 window and a reference pattern, it becomes a small drop with respect to a space of 4 dots before and after the change point (blank and image dots when all dots are the target pixel). Whether or not to replace can be determined. The reason why it can be applied to the four dots before and after the change point is that, for example, when the position of the dot De in FIG. It is. In order to solve this problem and add a small droplet to the position of the dot De, it is possible to make the window and the reference pattern 11 × 3 in size.

  That is, by increasing the size of the window and the size of the reference pattern, it is possible to detect the change point of the diagonal line near horizontal or vertical, and it is possible to add small droplets according to the inclination, and to improve the quality of the diagonal line. It can be made even more optimal. In other words, as described above, the size of the window and the reference pattern is not limited to that used in the above example, but depends on how much replacement with a small drop needs to be performed and whether the processing time is in time for the printing speed. Determined. Furthermore, since the data for pattern matching increases as this size increases, time is required for pattern matching. Therefore, from the processing time, the size should be as small as possible. On the other hand, how many dots before and after the change point should be made into small droplets is determined by the character quality by jaggy correction, so it is necessary to determine an optimum size from the processing speed and the character quality.

  When the ink as described above is used, it can be seen from the reduction of unevenness with the adjacent dots due to the spread of the ink that the character quality can be sufficiently improved even with the addition of small droplets, usually 4 dots, preferably 6 dots, The processing speed can also achieve a throughput of 10 PPM or more. Therefore, as the window size, m ≦ 13 in which 6 dots can be detected in the main scanning direction and n = 3 in the sub scanning direction are suitable.

  Next, another example of bolding will be described with reference to FIGS. In these examples, small droplets and medium droplets are used as small droplets, and the number of added dots is different.

  The example shown in FIG. 36 is an example in which a small drop (D61, D71) is added to a blank area of 1 dot before the change point, and the example shown in FIG. 37 is a medium drop (D61) in a blank area of 2 dots before the change point. , D71) and small droplets (D60, D72), the example shown in FIG. 38 is a medium dot (D61, D71) and small droplets (D60, D59, D72, In the example shown in FIG. 39, medium drops (D61, D60, D71, D72) and small drops (D59, D58, D73, D74) were added to the blank area of 4 dots before the change point. It is an example.

  In the example shown in FIGS. 40 to 42, after adding small droplets (D61 to D58, D71 to D74) to the 4-dot blank portion before the change point, the example shown in FIG. In the example in which the character portion of 1 dot is replaced with the medium droplet (D62, D70), the example shown in FIG. 41 is the medium droplet (D62, D70) and the small droplet (D63, D69) in the character region of 2 dots after the change point. 42, the example shown in FIG. 42 is an example in which the 3-dot character portion after the change point is replaced with a medium drop (D63, D64, D69, D68) and a small drop (D62, D70), as shown in FIG. In the example, the 4-dot character part after the change point is replaced with a medium drop (D64, D65, D68, D67) and a small drop (D62, D63, D70, D69).

  When comparing each of these examples in terms of processing speed, the example of FIG. 36 is the fastest, and becomes slower in the order of the examples of FIG. 37, FIG. 38. For example, in the example of FIGS. 36 to 39, the processing method may be executed only when the target pixel is blank. In the examples of FIGS. This is because it is necessary to perform pattern matching both in the case of image data and in the case of image dots (that is, all font data). In other words, font data with improved jaggies can be created at high speed by adding small droplets only to blanks. Moreover, by replacing only image dots with small drops, font data with improved jaggy can be created at high speed, but this is not desirable when bolding.

  The second reason is that the number of necessary reference patterns increases in the order of the examples in FIGS. 36, 37,... In order to implement the example of FIG. 37, a reference pattern for determining the second blank dot is required in addition to the reference pattern of the example of FIG. 36. In the example shown in FIG. This is because a reference pattern for determining the second dot is necessary, and in the example shown in FIG. 41, a reference pattern for determining the second dot is further required. Thus, as the example shown in FIG. 36 goes from the example shown in FIG. 43, the number of reference patterns for determination increases and the number of pattern matching increases.

  Next, the character contour portion having the above-described jaggy is detected, and the addition or replacement of the dot to the detected character contour portion is performed according to the contour correction pattern including the dot position for recording the dot and the dot size to be recorded there. The problem of the jaggy correction processing by performing and the solving means thereof will be described below.

  In other words, in the above-described jaggy correction, even if the character has a lower gradation and has a lighter density, such as a gray character, jaggy correction dots for density during single-sided printing are synthesized. Only the edges become darker, the characters appear to be trimmed, the character quality deteriorates, and the characters become difficult to read.

  Therefore, here, for example, a gray character with a reduced density by reducing the amount of ink adhering during double-sided printing is subjected to a jaggy correction process with an optimal density, and there is no black character or gray character with high visibility and no noticeable jaggy. Enable printing of colored characters.

First, a method different from the method described above for the jaggy correction will be described with reference to FIGS.
Here, pattern matching is performed using the reference pattern shown in FIG. 46, and when matching with the reference pattern, the target pixel at the position of the central blank portion is replaced with a pixel of a predetermined gradation that generates a small dot. For example, when the pattern matching with the pattern of FIG. 47 is performed using the reference pattern of FIG. 46, for example, the matching is performed when the pixel of the dot D80 becomes the target pixel, so that the dot D80 is shown in FIG. In addition, the dot D80 is replaced with a pixel of a predetermined gradation that generates a small dot.

  When jaggy correction is performed by replacing pixels in this way, the data format for jaggy correction represents each pixel with a plurality of bits. For example, as shown in FIG. 49, the input gradation is from 1 to 90 gradations. Fills with small drops, fills from 91 to 180 gradations with medium drops, and fills from 181 to 255 gradations with large drops. Thus, processing is performed to make a pixel of a value (90 gradations) that always becomes a small dot.

  As a result, small dots are formed in pixels to be replaced by performing jaggy correction.

Next, an example of jaggy correction processing for achromatic characters (black or gray characters) will be described with reference to FIG.
First, a character contour portion having jaggy is detected for the character, and a character subjected to jaggy correction for adding jaggy correction pixels according to the contour correction pattern is created. Then, halftone processing is performed thereafter to form a character obtained by performing jaggy correction processing on black or gray characters. At this time, the gradation value of the jaggy correction pixel to be added is set to such a gradation value that a dot designated by halftone processing is generated when it is desired to add a small droplet or a medium droplet.

  That is, here, a halftone process is performed on a character to which jaggy correction pixels are added to form an achromatic character.

Next, an example of character thickening processing (thickening processing) for achromatic characters will be described with reference to FIG.
First, a character outline portion is detected for a character, and a character subjected to thickening processing for adding a thickening correction pixel to the detected character outline portion is created. Then, halftone processing is performed thereafter to form a character that has been subjected to fattening processing on a gray character. At this time, the gradation value of the thickening pixel to be added is the same gradation as that of the character. Alternatively, a gradation value larger than the gradation value of the character may be used in order to express the outline portion deeply.

  In this case, ON / OFF switching of the character thickening process can be set by the user. In this case, the switching method can be switched according to the character size. For example, by thickening a character having a character size of 6 points or less, the character visibility is reduced due to ink bleeding, so that the character is not thickened. At this time, the switching size may be set by the user.

  That is, here, a halftone process is performed on a character to which pixels for thickening correction are added to form an achromatic character.

Next, an example of character outline enhancement processing for gray characters will be described with reference to FIG.
First, a character outline emphasis pixel is added for emphasizing the character outline by detecting the character outline of the character and replacing the detected character outline with a pixel having a higher gradation than the character area. Thus, a character subjected to the character outline enhancement process is created. Thereafter, halftone processing is performed to form a character that has been subjected to fattening processing on gray characters.

  At this time, the gradation value of the pixel for emphasizing the character outline added as described above is set to a gradation value larger than the gradation value of the character in order to emphasize the outline portion with a deep expression. It is also possible to enable the user to set ON / OFF switching for the character outline enhancement processing. In this case, the switching method can be switched according to the character size. For example, character outline enhancement processing is performed on characters having a character size of 6 points or less, and character visibility is reduced due to ink bleeding. Therefore, character contour enhancement processing is not performed. At this time, the switching size may be set by the user.

  That is, here, a halftone process is performed on the character replaced with the pixel for character outline emphasis to form an achromatic character.

Next, an example of character thickening jaggy correction processing for gray characters will be described with reference to FIG.
First, a character in which pixels for character thickening are added to the character is created, and then a gray character is formed by performing halftone processing. On the other hand, a jaggy correction pattern is applied to a solid character to form a jaggy correction dot, and the jaggy correction dot is applied to the formed gray character so that the gray character is fattened (jaggy processing). Characters with correction dots added) are formed.

  In other words, here, a character outline is detected, a pixel is added to the detected character outline, and the character is thickened, and the character is added to the character-added pixel. A tone process is performed, and then a dot for jaggy correction is added or replaced to form an achromatic character.

Next, another example of thickening jaggy correction processing for gray characters will be described with reference to FIG.
First, a character thickening pixel is added to a character, and a jaggy correction pixel is further added to thicken the character to perform the jaggy correction processing. After that, halftone processing is performed to form a character that is blackened or grayed out and subjected to jaggy correction processing.

  At this time, it is possible to allow the user to set ON / OFF switching for the character thickening process. In this case, the switching method can be switched according to the character size. For example, by thickening a character having a character size of 6 points or less, the character visibility is reduced due to ink bleeding, so that the character is not thickened. At this time, the switching size may be set by the user.

  In other words, here, a character outline is detected, a pixel is added to the detected character outline, and the character is thickened, and the character to which the character thickening pixel is added is jaggy. After adding or replacing the correction pixels, halftone processing is performed to form an achromatic character.

Next, an example of character outline enhancement jaggy correction processing for gray characters will be described with reference to FIG.
First, a character for emphasizing the character is replaced with a predetermined coefficient, a double-sided printing character is created with gradation values reduced for both sides, and then halftone processing is performed. Form. On the other hand, a jaggy correction pattern is applied to a solid character to form a jaggy correction dot, and the jaggy correction dot is applied to the formed double-sided printing character to add the jaggy correction dot to the double-sided printing character. Characters for double-sided printing that have been subjected to the character outline emphasis process are formed.

  That is, here, the character outline portion is detected, and the detected character outline portion is replaced with a pixel having a gradation larger than that of the character portion, so that the character outline is emphasized. A halftone process is performed on the added character, and then a character with jaggy correction dots added or replaced is formed.

Next, another example of character outline enhancement jaggy correction processing for gray characters will be described with reference to FIG.
First, a character outline enhancement pixel is added to a character, and a jaggy correction pixel is added to create a character that has been subjected to character outline enhancement jaggy correction processing. Thereafter, by performing halftone processing, a character subjected to the character outline enhancement jaggy correction processing is formed.

  At this time, it is possible to allow the user to set ON / OFF switching of the character outline emphasis process. In this case, the switching method can be switched according to the character size. For example, character emphasis is applied to characters with a character size of 6 points or less, and character visibility is reduced due to ink bleeding, so that the characters are not thickened. At this time, the switching size may be set by the user.

  That is, here, the character outline portion is detected, and the detected character outline portion is replaced with a pixel having a gradation larger than that of the character portion, so that the character outline is emphasized. Jagged correction dots are added or replaced to the added character, and then halftone processing is performed to form the character.

  The above-described jaggy correction, bolding process, thickening jaggy correction process, character outline enhancement process, and character outline enhancement jaggy correction process are all processed on a computer as a program (printer driver), for example, as shown in FIG. Alternatively, as shown in FIG. 45, a part of the jaggy correction or the like may be programmed and processed on a computer, and the rest may be hardware and processed on the image forming apparatus side. Furthermore, it is possible to adopt a configuration in which all processing is implemented in hardware and performed on the image forming apparatus side.

  A program for causing a computer to execute the above-described image processing method can be easily distributed in large quantities or copied by recording it on a storage medium. In terms of storage of the program, it can be stored on a nonvolatile storage medium. Long-term storage is possible. Furthermore, since current computers include external storage medium reading means such as a floppy disk drive and a CD / DVD drive as standard or optional, it is possible to easily introduce them into the computer using these storage media. Further, it can be provided to the image processing apparatus or the image forming apparatus by a download method using the Internet.

  In the above embodiment, the present invention has been described with reference to an example in which the present invention is applied to an ink jet recording apparatus. However, the present invention can also be applied to a printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, etc. The present invention can also be applied to an image forming apparatus using a recording liquid other than the above, an image processing apparatus that gives print data (image data) to the image forming apparatus, and a program such as a printer driver installed in the image processing apparatus.

FIG. 3 is an explanatory side view illustrating an overall configuration of a mechanism unit of an image forming apparatus that outputs image data generated by the image processing method according to the present invention. It is principal part plane explanatory drawing of the mechanism part. FIG. 3 is an explanatory cross-sectional view along the longitudinal direction of the liquid chamber showing an example of the recording head of the apparatus. FIG. 4 is an explanatory cross-sectional view of the recording head along the lateral direction of the liquid chamber. It is a block diagram which shows the outline | summary of the control part of the apparatus. It is a block diagram which shows an example of the printing control part of the control part. It is explanatory drawing which shows an example of the drive waveform produced | generated and output by the drive waveform production | generation part of the same printing control part. It is explanatory drawing explaining the relationship between the droplet size to discharge and a drive waveform. FIG. 2 is a block diagram illustrating an example of a printing system including the image forming apparatus and the image processing apparatus according to the present invention. It is a block explanatory view showing an example of an image processing device in the system. FIG. 3 is a functional block diagram for explaining an example of a configuration of a printer driver as a program according to the present invention. FIG. 6 is a functional block diagram for explaining another example of the configuration of the printer driver. It is explanatory drawing with which it uses for description of the dot notation used in a figure. It is explanatory drawing with which it uses for description of normal composite black. It is explanatory drawing with which it uses for description of the dot arrangement example in the case of using composite black similarly. It is explanatory drawing with which it uses for description of 4 color mixing black used with the image processing method which concerns on this invention. It is explanatory drawing with which it uses for description of the production | generation of 4 color mixed black in the image processing method which concerns on this invention. It is explanatory drawing with which it uses for description of an example of the relationship between an image mode and a black image ratio. It is explanatory drawing with which it uses for description of the production | generation of 4 color mixed black according to a black image ratio. It is explanatory drawing with which it uses for description of the 1st example of the production | generation process of the image data in the image processing method which concerns on this invention. It is explanatory drawing with which it uses for description of the 1st example of the production | generation process of the image data which makes the dot formation position the same. It is explanatory drawing with which it uses for description of the 2nd example of the production | generation process of the image data which makes the dot formation position the same. It is a flowchart with which it uses for description of the production | generation process of the image data in the image processing method concerning this invention. It is explanatory drawing with which it uses for description of the production | generation process of image data in the case of performing a jaggy correction process. It is explanatory drawing with which it uses for description of the production | generation process of the image data in the case of performing a bolding process. It is explanatory drawing with which it uses for description of the production | generation process of the image data in the case of performing a fattening jaggy correction process. FIG. 10 is a flowchart for explaining processing for generating image data by performing jaggy correction and fattening jaggy correction processing. It is explanatory drawing with which it uses for description of the amount of ink used. It is explanatory drawing of the window size used for pattern matching. It is a flowchart with which it uses for description of a bolding process. It is explanatory drawing of the reference pattern of a 3x3 size window size with which it uses for description of the specific example of a bolding process. It is explanatory drawing with which it uses for the description at the time of similarly applying the reference pattern of FIG. It is a flowchart with which it uses for description of the other example of a bolding process. It is explanatory drawing of the reference pattern of the window size of 9x3 size similarly used for description of the specific example of a bolding process. FIG. 35 is an explanatory diagram for explaining the case where the reference pattern of FIG. 34 is applied. It is explanatory drawing with which it uses for description of the 1st example of the thickening by jaggy correction. It is explanatory drawing similarly provided to description of a 2nd example. It is explanatory drawing similarly provided to description of a 3rd example. It is explanatory drawing similarly provided to description of a 4th example. It is explanatory drawing similarly provided to description of a 5th example. It is explanatory drawing similarly provided to description of a 6th example. It is explanatory drawing similarly provided to description of a 7th example. It is explanatory drawing similarly provided to description of an 8th example. FIG. 3 is a functional block diagram for explaining an example of a configuration of a printer driver when performing jaggy correction. FIG. 6 is a functional block diagram for explaining another example of the configuration of the printer driver. It is explanatory drawing of the reference pattern with which it uses for description of the other example of a jaggy correction process. It is explanatory drawing which shows an example of a target pattern similarly. It is explanatory drawing of the pattern after a jaggy correction | amendment similarly. It is explanatory drawing which shows an example of the relationship between the input gradation and the dot size (droplet size) to be used similarly. It is explanatory drawing with which it uses for description of an example of the jaggy correction process with respect to an achromatic character. It is explanatory drawing with which it uses for description of an example of the fattening process with respect to an achromatic character. It is explanatory drawing with which it uses for description of an example of the outline emphasis process with respect to an achromatic character. It is explanatory drawing with which it uses for description of an example of the fattening jaggy correction process with respect to an achromatic character. It is explanatory drawing with which it uses for description of the other example of the fattening jaggy correction process with respect to an achromatic color character. It is explanatory drawing with which it uses for description of an example of the outline emphasis jaggy correction process with respect to an achromatic character. It is explanatory drawing with which it uses for description of the other example of the outline emphasis jaggy correction process with respect to an achromatic character.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Carriage 7 ... Recording head 207 ... Print control part 208 ... Head driver 400 ... Image processing apparatus 500 ... Inkjet printer 411 ... Printer driver (program)
416: Halftone processing unit

Claims (10)

In an image processing method for generating image data of an image output by an image forming apparatus capable of forming an image using a black recording liquid and at least one color recording liquid,
When the input image is black, the image is formed with the black recording liquid, and the image data for generating the color recording liquid is used for the image ,
In the image data, the amount of black recording liquid used per unit area is 20 to 100% when an image having the same density is formed using only the black recording liquid, and the amount of color recording liquid used for each color per unit area. Is an amount of 5 to 35% of the case where an image having the same density is formed with only the black recording liquid, and data for forming dots of the black recording liquid and the color recording liquid at the same position, and
The image data is data in which the dots of the color recording liquid are arranged at half or more of the positions where the dots of the black recording liquid are arranged with a gradation of 90% or more,
When using two or more color recording liquids, make the dot placement and dot size of each color the same,
For each color recording liquid, dots of each color are arranged in halftone processing using the same dither mask,
While forming an image with the black recording liquid, performing a jaggy correction for correcting a step-like change portion of the image for a black character image that uses the color recording liquid for the image, and
The jaggy correction includes a correction pattern for performing jaggy correction for correcting a step-like change portion of an image for a single color character composed of one color recording liquid, and an image pattern of a character using a black recording liquid and a color recording liquid. An image processing method characterized by combining and performing . 2. The image processing method according to claim 1 , wherein an image is formed with the black recording liquid, and a black character image that uses the color recording liquid for the image is subjected to a bolding process for thickening at least an edge portion of the image. An image processing method. The image processing method according to claim 2 , wherein whether or not to perform the bolding process is switched according to the size of the character. The image processing method according to claim 3 , wherein a size of the character for switching whether or not to perform the bolding process can be set. 3. The image processing method according to claim 2 , wherein whether or not to perform the bolding process is switched according to an instruction from the outside. The image processing method according to any one of claims 1 to 5, together to form an image in the black recording liquid, when to use the color recording liquid to the image, black by being mixed as the color recording liquid An image processing method comprising using a plurality of types of color recording liquids. A program to perform the processing for generating image data to be sent to the image forming apparatus to a computer, the program characterized by executing the image processing method according to any one of the claims 1 to computer 6. A storage medium in which the program according to claim 7 is stored. Keep the image processing apparatus for generating image data to be output to the image forming apparatus capable of forming an image using a black recording liquid and at least one color recording liquid according to any one of claims 1 to 6 An image processing apparatus comprising means for executing an image processing method. Keep the image forming apparatus capable of forming an image using a black recording liquid and at least one color recording liquid, and a means for performing the image processing method according to any one of claims 1 to 6 An image forming apparatus.

Images