JP2009045800A - Image forming method and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method and an image forming device capable of obtaining sufficient black density when printing in black using an ink of K and an ink other than K. <P>SOLUTION: In the image forming method when printing black by the image forming device having a recording head in which a plurality of nozzles for discharging inks of colors of K and other than K are arranged in a main scanning direction, reciprocatingly and relatively moving the recording head to a recording medium, and carrying out recording action in an outward route and a homeward route in the reciprocating action, the above problem is solved by discharging the ink to the same recording position from the nozzle of K and from a nozzle behind the nozzle of K when there is the nozzle located behind the nozzle of K in the moving direction of the recording head. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming method and an image forming apparatus, and more particularly to an image forming method and an image forming apparatus for printing black using inks other than K and K.

  Many inkjet printers form images using a plurality of colors of ink including four colors of cyan (C), magenta (M), yellow (Y), and black (K) (for example, Patent Document 1). For example, in the case of an ink jet printer equipped with the above four types of ink, in order to form a color image other than the four colors mounted on the recording medium, a plurality of color ink droplets are juxtaposed or placed at the same position. Landing and mixing colors on the recording medium.

  By the way, when printing using only specific ink is continued for a long period of time as in monochrome designated printing, for example, a phenomenon occurs in which unused ink dries on the nozzle surface and the nozzle is clogged.

  Therefore, in general, for each ink, the amount of ink to be used in a certain period is specified, and if the condition is not satisfied, the nozzle is clogged by performing the ink suction operation to the unused nozzle. A maintenance mechanism is built in.

  However, the ink consumed by the ink suction operation described above makes a contradiction that, from the user's standpoint, the amount of ink that should not be used decreases, and the time required for maintenance is a waiting time added to the printing time. End up.

In order to solve this problem, composite black has been devised to express black by juxtaposing inks other than K and K or recording them at the same position. According to this, the amount of K ink consumed in monochrome printing is reduced, and color ink is used correspondingly, so that the total ink usage is not increased beyond the amount of ink required for printing. The color ink can be prevented from drying, and the K ink can be saved and the maintenance time can be shortened.
JP 2004-106392 A

  However, the black expression by the composite black described above has a problem that the density becomes lower than the printing by only the K ink. This is due to the fact that the dominant color changes depending on the order of the ink color layers following the ink landing order. This is because when another dot is overlapped with the previously landed dot, the dot hit later than the previously landed dot tends to sink in the depth direction of the paper.

  In the case of an inkjet printer that performs image recording by scanning a recording head a plurality of times on a predetermined image area, droplets can be ejected by changing the overlapping order of each ink (for example, K, C, M, Y). Therefore, C, M, and Y can be used in combination while keeping the dominant color always at K. However, in the case of an ink jet printer that records an image in one scan, the ink droplet ejection order is uniquely determined by the arrangement order of the heads. For this reason, depending on the arrangement order of the heads, there is a problem that it is difficult to obtain an intended density.

  The present invention has been made in view of the above points, and provides an image forming method and an image forming apparatus capable of obtaining a sufficient black density when printing black using inks other than K and K. With the goal.

  In order to solve the above problems, the present invention includes a recording head in which a plurality of nozzles that eject inks of colors other than K and K are arranged in the main scanning direction, and the recording head is relative to the recording medium. An image forming method for printing black by an image forming apparatus that performs a reciprocating movement and performing a recording operation in the forward path and the backward path of the reciprocating movement, the K nozzle for the same recording position, When there is a nozzle positioned after the K nozzle in the moving direction of the recording head, ink is ejected from the nozzle.

  In order to solve the above-described problem, the present invention includes a recording head in which a nozzle for ejecting ink of a color other than K is disposed so as to have a deviation in the sub-scanning direction with respect to the K nozzle. Is an image forming method in which black is printed by an image forming apparatus that performs a reciprocating movement relative to a recording medium and performing a recording operation in the forward path and the backward path of the reciprocating motion. And recording ink other than K at a recording position where K ink has already been recorded in the return path in which the recording head is moved in the sub-scanning direction with respect to the forward path.

  In order to solve the above-described problem, the present invention includes a recording head in which a plurality of nozzles that eject inks of colors other than K and K are arranged in the main scanning direction, and the recording head is attached to the recording medium. An image forming method in which black is printed by an image forming apparatus which performs a reciprocating movement and performs a recording operation in a forward path and a return path of the reciprocating movement, and in a main scanning direction and a sub scanning with respect to a K recording position. Ink other than K is recorded at a recording position shifted by a half pitch in at least one of the directions.

  According to the present invention, it is possible to provide an image forming method and an image forming apparatus capable of obtaining a sufficient black density when printing black using inks other than K and K.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a color ink jet recording apparatus according to an embodiment of the present invention.

  In FIG. 1, a color ink jet recording apparatus 100 includes a frame 1, guide rails 2 and 3, a carriage 4, a guide plate 5, a drive gear 6, a sprocket gear 7, a platen 8, a feed knob 8a, a pressure roller 9, and a head unit 10. (Recording head) and the like. In the figure, reference numeral 15 denotes a recording paper (recording medium).

  In the color ink jet recording apparatus 100, the carriage 4 is mounted so as to be movable with respect to the guide rails 2 and 3 horizontally mounted on the frame 1, and the head unit 10 is mounted thereon. The carriage 4 moves in the direction of the arrow A along the guide rails 2 and 3 by driving a motor (not shown) or the like.

  The recording paper 15 set on the guide plate 5 is taken in by a platen 8 having a feed knob 8a that is rotated via a drive gear 6 and a sprocket gear 7 by a drive source (not shown). It is conveyed in the direction of arrow B by the pressure roller 9 that is in pressure contact therewith.

  The color inkjet recording apparatus 100 conveys the recording paper 15 in the sub-scanning direction (B direction) while moving and scanning the head unit 10 in the main scanning direction (A direction), and ejects ink droplets from the head unit 10 to record paper. 15 prints an image.

  FIG. 2 is a diagram illustrating a schematic configuration example of a head unit mounted on the color inkjet recording apparatus according to the embodiment of the present invention. In FIG. 2A, the head unit 10 is composed of ejection units 11 and 12 corresponding to the respective colors. Usually, recording is performed by ejecting ink droplets from the head unit 10 in which the ejection units 11 and 12 are integrated to the paper surface. Each of the ejection units 11 and 12 has a plurality of ink ejection nozzles, and each can eject ink (pigment-based ink) having a multivalued drop amount. FIG. 2B shows a state where ink droplets ejected from the head unit 10 are recorded on the recording paper 15.

  FIG. 3 is a diagram for explaining an operation example of the head unit at the time of bidirectional recording on a recording sheet. In FIG. 3, the head unit 10 includes ejection units 11 and 12 arranged in the order of black, cyan, magenta, and yellow (hereinafter referred to as K, C, M, and Y) in the main recording forward recording direction. Yes. The color inkjet recording apparatus 100 reciprocates such a head unit 10 in the main scanning direction, and performs printing in both the forward pass and the return pass (injecting ink droplets from the nozzles). The order of colors and the number of colors in the head unit 10 are not necessarily limited to this example. For example, a different arrangement order or more colors may be handled depending on the ink characteristics, the design concept, or the like.

  FIG. 4 is a diagram showing an example of the colorant distribution inside the recording paper when the pigment-based ink is driven into the same location. In the drawing, a cross section of the recording paper 15 is shown.

  As shown in FIG. 4, the colorant contained in the ink that was previously ejected (in this example, A-color droplets) stays on the paper surface, and the ink that was ejected later (in this example, the B-color ink) Drops) sink into the paper. As a result, the characteristics of the colorant on the recording surface of the recording paper 15 become stronger, and the A color that has been placed first becomes the dominant color. Such a colorant fixing characteristic tends to be stronger in the pigment-based ink shown in this example than in the dye-based ink.

  Therefore, when performing image formation (hereinafter referred to as “composite black”) expressing black by juxtaposing or recording inks other than K and K at the same position, changes in density and color tone due to the overlapping order of colors are taken into consideration. There is a need. In particular, when bi-directional recording is employed to improve the printing speed, the dominant color differs between forward recording and backward recording, and there is a risk that the density and color tone may not be suitable for black expression.

FIG. 5 is a diagram showing an example of the dominant color and the controlled color at the time of the composite black bidirectional recording of each color head according to the present embodiment. As shown in the head unit 10 of the present embodiment, the dominant strength expected at the time of the forward recording and the backward recording when the ejection units are arranged in the order of KMCY is shown below. The following relational expressions are simplified for the sake of explanation.
Dominant strength expected at the time of outbound recording: K>C>M> Y (1)
Dominance strength expected at the time of return track recording: Y>M>C> K (2)
Thus, it is shown that the superiority and inferiority are reversed for each color component at the time of forward recording and at the time of backward recording. However, the degree of superiority or inferiority may vary depending on the recording paper and ink composition.

  Note that the above-described dominant strength is established in the overlapping portion of ink, and not only the inks that have been ejected at the same position overlap, but also the spread of the landed ink and the ink landed in the vicinity thereof overlap. It also holds in the part.

  In order to achieve a density and color tone suitable for black expression in composite black, it is important to make K the dominant color. However, the method of making K the dominant color may vary depending on the configuration of the head unit 10 and the recording method. This point will be described with reference to FIGS.

  FIG. 6 is a diagram illustrating a first configuration example of the head unit for explaining a method of making K the dominant color. A head unit 10a shown in FIG. 6 is an example of the head unit 10, and is composed of two ejection units 16a and 16b (hereinafter collectively referred to as “ejection unit 16”). In each ejection unit 16, nozzle rows N1 and N2 composed of a plurality of nozzles 16n arranged in a direction orthogonal to the main scanning direction are arranged in the main scanning direction.

  When the head unit 10 is configured as the head unit 10a, that is, when the nozzles of the respective colors K, C, M, and Y are in the same row in the main scanning direction, the color inkjet recording apparatus 100 performs the forward recording. Each color is ejected in the order of K, C, M, and Y, and only K is ejected during the return pass recording. As a result, the dominant color can always be K. This image forming method is based on the idea that ink other than K is not ejected before K, and can be applied regardless of the color arrangement in the head unit 10. For example, in the case of a head in which colors are arranged in the order of Y, M, K, and C, K and C are ejected during forward recording, and K, M, and Y are ejected during backward recording. The color can always be K.

  On the other hand, FIG. 7 is a diagram showing a second configuration example of the head unit for explaining a method of making K the dominant color. The head unit 10b shown in FIG. 7 is composed of two ejection units 17a and 17b (hereinafter collectively referred to as “ejection unit 17”). In each ejection unit 17, nozzle rows N1 and N2 each composed of a plurality of nozzles 17n arranged in a direction orthogonal to the main scanning direction are arranged in the main scanning direction. Here, the nozzles 17n of the nozzle row N1 and the nozzles 17n of the nozzle row N2 are shifted by a half pitch of the pitch (nozzle pitch) between the nozzles 17n in the sub-scanning direction.

  In the head configuration shown in FIG. 7, the nozzles for ejecting K and the nozzles for ejecting other inks are displaced in the main scanning direction, so that K, C, M, and Y colors are applied to the same pixel in one scan. I can't drip. Therefore, when the head unit 10 is configured as the head unit 10b, the color inkjet recording apparatus 100 deposits only K at the time of forward recording and in the order of Y, M, C, and K at the time of backward recording. Drop each color. At this time, the recording paper is fed in the sub-scanning direction, and Y, M, and C, which are ejected at the time of backward recording, are ejected onto the same pixel as K that is ejected at the time of outward recording, so The droplet is ejected and the dominant color can always be K.

  However, depending on the feed width of the recording paper in the sub-scanning direction, there may occur a region where Y, M, and C that are ejected during the backward pass recording are ejected onto pixels that are not printed with K (for example, FIG. 7). 17e). For this area only, it is conceivable that Y, M, and C are not ejected at the time of backward recording, and only K is ejected at that time, but in this case, the Y, M, and C nozzles are used at the time of forward recording and at the time of backward recording. In either case, it is no longer used, and there is a risk of causing adverse effects such as drying of the nozzle surface and ink clogging.

  Therefore, in this embodiment, it is allowed to use ink other than K as the dominant color. However, the color inkjet recording apparatus 100 increases the number of pixels in which K is the dominant color, and varies the amount of ink droplets and recording positions other than K depending on whether K is the dominant color.

  Specifically, for pixels for which K is the dominant color (pixels for which K has been printed first), when ink other than K is printed during return pass printing, relative to the pixels for which K has already been printed. Therefore, ink other than K is preferentially applied to a pixel having a small droplet amount. For example, FIG. 8 is a schematic diagram illustrating an example of the K ink recording position and the amount of droplets. Ink other than K is applied to the pixel indicated by 20b having a smaller droplet amount than the pixel indicated by 20a.

  On the other hand, for pixels in which ink other than K is the dominant color (pixels other than K are ejected first), when ink other than K is ejected during return pass recording, Ink other than K is preferentially applied to a pixel having a relatively large amount of K droplets to be injected after ink other than (in the subsequent outbound path). For example, in FIG. 8, ink other than K is applied to the pixel indicated by 20a having a larger droplet amount than the pixel indicated by 20b. It should be noted that it is desirable to reduce the amount of ink droplets other than K for pixels for which K has not yet been printed, compared to pixels for which K has already been printed. For example, the amount of ink droplets other than K for the pixels for which K has not yet been printed is the smallest among the multi-value (multi-stage) droplet amounts (for example, large droplets, medium droplets, small droplets) that can be ejected. Shall be.

  Further, in the present embodiment, regardless of whether K is the dominant color or not, if M1 is the drop amount of K ink and M2 is the drop amount of ink other than K, M1 ≧ M2 is established. That is, in the same pixel, the amount of ink droplets other than K is prevented from becoming larger than the amount of ink droplets K.

  FIG. 9 is a schematic diagram illustrating an example of a position where ink other than K is landed in the present embodiment. In FIG. 9, reference numeral 18a denotes a recording position (pixel) of K ink. Reference numeral 18b denotes an ink recording position other than K when K is the dominant color at the same recording K position as 18a. Reference numeral 18c denotes the recording position of ink other than K when the ink other than K is the dominant color in the same pixel as 18a. In the figure, 18b is 6 drops and 18c is 3 drops. As described above, the color ink jet recording apparatus 100 reduces the number of pixels to which ink other than K is applied when ink other than K is the dominant color.

  When K is the dominant color, each ink other than K may be applied to the same pixel, or may be distributed to a plurality of pixels. For example, FIG. 10 is a diagram illustrating an example of how to record ink other than K when K ink is the dominant color. In FIG. 10, (A) shows how inks other than K (C, M, Y) are driven into the same pixel. Further, (B) shows a state in which each ink other than K is scattered and applied to different pixels. However, when a plurality of inks other than K are applied to the same pixel, it is preferable that the inks other than K have a relatively large drop amount for the same drop amount or a color with a higher black density.

  On the other hand, when ink other than K becomes the dominant color, each ink other than K may be dispersed in a plurality of pixels. For example, FIG. 11 is a diagram illustrating an example of how to record ink other than K when ink other than K becomes the dominant color. FIG. 11 shows a state in which C and Y, M and K, and Y and K are distributed and printed in different pixels. By doing so, the dominant strength of ink other than K can be reduced.

  By the way, regarding the drop amount and the recording position of the ink other than K described above, the explanation is given for the case where ink other than K and K is applied to the same pixel. However, the ink other than K is shifted from the recording position of K and applied. May be dropped. For example, FIG. 12 is a diagram illustrating an example in which ink other than K is recorded while being shifted from the K recording position. 12A shows an example in which ink other than K is recorded with a half-pitch shift in the main scanning direction with respect to the K recording position. (B) shows an example in which ink other than K is recorded with a half-pitch shift in the sub-scanning direction with respect to the K recording position. (C) shows an example in which ink other than K is recorded with a half-pitch shift in both the main scanning direction and the sub-scanning direction with respect to the K recording position.

  In this case, in the vicinity of the pixel having the dominant color K, it is preferable that ink other than K is preferentially applied to the vicinity of the pixel having a relatively small K ink droplet amount. On the other hand, with respect to the vicinity of a pixel where K is not the dominant color, ink other than K is preferentially applied to the vicinity of the pixel into which K ink having a relatively large droplet amount is applied among the K ink used. Good. The amount of ink droplets other than K may not be minimized.

  In the above description, an example using so-called one-pass printing in which an image is formed on the recording paper 15 by one main scanning as the recording method has been described. So-called multi-pass printing in which an image is formed by performing a plurality of main scans with different nozzle groups or different nozzle groups may be used. Further, the recording methods of 1-pass printing and multi-pass printing may be appropriately combined.

  Multipass printing will be described. Here, a case where an image is completed by executing four main recording scans (4 passes) for one recording area will be described as an example.

  FIG. 13 is a block diagram illustrating a configuration example of the image processing unit of the color inkjet recording apparatus according to the present embodiment. In FIG. 13, the image processing unit 19 includes an input terminal 19a, a recording buffer 19b, a pass number setting unit 19c, a mask processing unit 19d, a mask pattern table 19e, a head I / F unit 19f, a recording head 19g, and the like. .

  The bitmap data input from the input terminal 19a is stored at a predetermined address in the recording buffer 19b by the recording buffer control unit. The recording buffer 19b has a capacity capable of storing bitmap data for one scan and the paper feed amount, and constitutes a ring buffer in paper feed amount units such as a FIFO memory. The recording buffer control unit controls the recording buffer 19b, and activates the printer engine of the color inkjet recording apparatus 100 when bitmap data for one scan is stored in the recording buffer 19b. Subsequently, the recording buffer control unit reads bitmap data from the recording buffer 19b in accordance with the position of each nozzle of the recording head 19g (head unit 10), and inputs it to the pass number setting unit 19c. When the next scan bit map data is input from the input terminal 19a, the recording buffer control unit transfers the bit map data to an empty area of the recording buffer 19b (an area corresponding to the paper feed amount for which recording has been completed). The recording buffer 19b is controlled to store.

  Next, a specific configuration example of the pass number setting unit 19c in the image processing unit 19 will be described. The path number setting unit 19c determines the number of divided paths and outputs the number of paths to the mask processing unit 19d. The mask pattern table 19e is stored in advance according to the number of divided passes in which a necessary mask pattern is determined from mask patterns stored in advance, for example, mask patterns such as 2-pass printing, 4-pass printing, and 8-pass printing. Select and output to mask processing 19d. The mask processing unit 19d masks the bitmap data stored in the recording buffer 19b for each pass recording using a mask pattern and outputs the masked data to the head I / F unit 19f. The head I / F unit 19f rearranges the masked bitmap data in the order used by the recording head 19g and transfers it to the recording head 19g.

  By using multi-pass printing in this way, it is possible to perform droplet ejection by changing the overlapping order of each ink (for example, K, C, M, Y), so that the dominant color is always kept at K, C, M and Y can also be used in combination. In one-pass printing, conspicuous white stripes and density unevenness can be averaged to make them inconspicuous.

  In this embodiment, the color ink jet recording apparatus 100 that discharges liquid ink is described as a representative example. However, as an ink discharging mechanism, a mechanism that uses a piezoelectric effect by a piezoelectric element or a heating element that generates heat when energized is used. The present embodiment may be applied to an image forming apparatus that uses a film boiling type. Further, the present embodiment may be applied not only to a serial head but also to a line head type image forming apparatus.

  Further, if the image forming apparatus has a mode for expressing black with the above-described composite black and a mode for expressing with black K ink, a mode for expressing with black if any ink has not been used for a long time. The above modes may be switched automatically depending on the use status of each ink, or by external input information (user selection) such as user preferences.

  Furthermore, in the mode using composite black, ink other than K is used when the usage ratio of K ink is extremely higher than the usage ratio of inks other than K, such as text data, or when monochrome printing is designated. Depending on the format of the input data (data to be printed), such as by increasing the amount of usage (ratio of use) relative to other than text data or when specifying color printing, etc. The balance of the amount of ink contained in each ink may be adjusted according to the input from (1). At this time, it is possible to adjust the balance of the amount of ink contained while keeping the total ink consumption equal to the K ink single color mode, or increase the total ink consumption to increase the density. The printing cost may be reduced by reducing the total amount of ink used.

  Next, print control that can be used in the present invention will be described. Here, an example in which cross control is applied will be described. “Cross control” refers to control that cooperatively overlaps both driving in the main scanning direction of the carriage 4 on which the head unit 10 is mounted and driving in the sub-scanning direction when the recording paper 15 is transported. In order to speed up the printing process, ideally, the main scan (CR) is started before the sub-scan (LF) is completed, and the LF is stopped just when the CR reaches the recording area. Timing is managed. If such time management is not performed, the CR reaches the recording area while the LF is operating, causing skew recording, and conversely, no recording is performed without overlapping with the LF driving. A CR running section will occur.

Although the image forming method and the image forming apparatus in the present embodiment have been described above, the scope of application of the present invention is not limited to the configuration of the present embodiment. For example, the above-described image forming method may be provided in one or both of a host computer and an image forming apparatus that request printing (send print data) to the image forming apparatus. It may be configured as a configured image forming system.
In the above-described embodiment, the CPU of the host computer may perform all of the series of image processing, or a part or all of the processing may be performed by the image forming apparatus.

  Further, the present invention may be in the form of a program for causing a computer to execute the above-described image forming method, or in the form of a computer-readable recording medium on which the program is recorded. Here, the program includes a printer driver that can be incorporated into a computer.

  An embodiment of a recording medium storing a program and data for realizing an image forming method according to the present invention will be described. Specifically, a CD-ROM, a magneto-optical disk, a DVD-ROM, an FD, a flash memory, a memory card, a memory stick, and various other ROMs and RAMs can be assumed as the recording medium. By causing a computer to execute the above-described steps of the embodiment of the present invention on these recording media and recording and distributing a program for realizing the functions of the above-described image forming method, the functions can be easily realized. Then, the recording medium as described above is mounted on an information processing apparatus such as a computer and the program is read by the information processing apparatus, or the program is stored in a storage medium provided in the information processing apparatus. By reading, the function of the image forming method according to the present invention is executed.

  As described above, according to the image forming method or the image forming apparatus of the present embodiment, K is governed regardless of the nozzle arrangement, color arrangement, scanning method, paper feed width in the sub-scanning direction, and the like in the recording head. Can be color. Or, even if ink other than K becomes the dominant color, the dominant intensity can be minimized. As a result, it is possible to express black by composite black at a higher density than before.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to such specific embodiment, In the range of the summary of this invention described in the claim, various deformation | transformation・ Change is possible.

1 is a perspective view showing a schematic configuration of a color inkjet recording apparatus in an embodiment of the present invention. It is a figure which shows the example of schematic structure of the head unit mounted in the color inkjet recording device in embodiment of this invention. FIG. 6 is a diagram for explaining an operation example of a head unit during bidirectional recording on a recording sheet. FIG. 6 is a diagram illustrating an example of colorant distribution inside recording paper when pigment-based ink is driven into the same location. FIG. 5 is a diagram illustrating an example of a dominant color and a controlled color at the time of bidirectional recording according to the arrangement of each color head in the present embodiment. It is a figure which shows the 1st structural example of the head unit for demonstrating the method to make K a dominant color. It is a figure which shows the 2nd structural example of the head unit for demonstrating the method to make K a dominant color. FIG. 6 is a schematic diagram illustrating an example of a recording position and a droplet amount of K ink in the present embodiment. It is a schematic diagram which shows an example of the position which inks other than K land. It is a figure which shows an example of the recording method of ink other than K in case K ink becomes a dominant color. It is a figure which shows an example of the recording method of inks other than K when inks other than K become dominant colors. FIG. 6 is a diagram illustrating an example in which ink other than K is recorded while being shifted from a K recording position. 2 is a block diagram illustrating a configuration example of an image processing unit of the color inkjet recording apparatus according to the present embodiment. FIG.

Explanation of symbols

1 Frame 2, 3 Guide rail 4 Carriage 5 Guide plate 6 Drive gear 7 Sprocket gear 8 Platen 8a Feed knob 9 Pressure roller 10, 10a, 10b Head unit 11, 12 Injection unit 15 Recording paper 16a, 16b, 17a, 17b Injection unit 16n, 17n Nozzle N1, N2 Nozzle array 17e Recording paper feed width 18a K Ink recording positions 18b, 18c Ink recording positions other than K 19a Input terminal 19b Recording buffer 19c Pass number setting unit 19d Mask processing unit 19e Mask pattern table 19f Head I / F unit 19g Head unit 20a, 20b K ink droplet volume 100 Color inkjet recording apparatus

Claims (17)

A recording head having a plurality of nozzles for discharging ink of colors other than K and K arranged in the main scanning direction, the recording head being reciprocated relative to the recording medium, An image forming method for printing black by an image forming apparatus that performs a recording operation in a return path,
An image forming method, wherein, when there are K nozzles and nozzles positioned after K nozzles in the moving direction of the recording head for the same recording position, ink is ejected from the nozzles. A recording head arranged so that a nozzle for discharging ink of a color other than K has a deviation in the sub-scanning direction with respect to the K nozzle, and the recording head is reciprocated relative to the recording medium; An image forming method for printing black by an image forming apparatus that performs a recording operation in a forward path and a backward path of the reciprocating motion,
Only K ink is recorded in the forward path, and ink other than K is recorded in a recording position where K ink has already been recorded in the return path in which the recording head is moved in the sub-scanning direction with respect to the forward path. An image forming method. For the first recording position where K ink is recorded in the forward path, for the recording position where the amount of K ink droplets is relatively small in the first recording position in the return path. Preferentially record ink other than K,
With respect to the second recording position where K ink is not recorded in the forward path, recording with a relatively large amount of K ink droplets recorded later in the second recording position is performed in the return path. 3. The image forming method according to claim 2, wherein ink other than K is preferentially recorded with respect to the position.   4. The image forming method according to claim 3, wherein the amount of ink droplets other than K is smaller at the second recording position than at the first recording position in the return path.   5. The image forming method according to claim 3, wherein, in the return path, the second recording position has fewer positions for recording inks other than K than the first recording position. 6.   When recording K ink and a plurality of inks other than K at the same recording position, the amount of ink droplets other than K is equal or the amount of ink droplets with high black density is relatively increased. The image forming method according to claim 1. A recording head having a plurality of nozzles for discharging ink of colors other than K and K arranged in the main scanning direction, the recording head being reciprocated relative to the recording medium, An image forming method for printing black by an image forming apparatus that performs a recording operation in a return path,
An image forming method comprising: recording an ink other than K at a recording position shifted by a half pitch in at least one of a main scanning direction and a sub-scanning direction with respect to a K recording position.   The image forming method according to any one of claims 1 to 7, wherein an ink other than K is used when black is printed in accordance with a use status of ink other than K or input information from the outside.   The image forming method according to claim 8, wherein the usage state is an unused period of ink other than K. 10.   10. The image forming method according to claim 1, wherein the usage ratio of each ink other than K and K is adjusted in accordance with the format of data to be printed or input information from the outside.   11. The image forming method according to claim 10, wherein when monochrome printing is designated as input information from the outside, the use ratio of ink other than K is relatively increased.   12. The image forming method according to claim 10, wherein the use ratio of inks other than K and K is adjusted at a total ink consumption equivalent to that when printing is performed using only K.   12. The image forming method according to claim 10, wherein the use ratio of inks other than K and K is adjusted by increasing the total ink consumption as compared with the case of printing only with K.   12. The image forming method according to claim 10 or 11, wherein the total ink consumption is reduced and the usage ratio of inks other than K and K is adjusted as compared with the case of printing only with K. A recording head having a plurality of nozzles for discharging ink of colors other than K and K arranged in the main scanning direction, the recording head being reciprocated relative to the recording medium, An image forming apparatus that performs a recording operation in a return path,
In black printing, when there are K nozzles and nozzles positioned after the K nozzles in the moving direction of the recording head for the same recording position, ink is ejected from the nozzles. Image forming apparatus. A recording head arranged so that a nozzle for discharging ink of a color other than K has a deviation in the sub-scanning direction with respect to the K nozzle, and the recording head is reciprocated relative to the recording medium; An image forming apparatus that performs a recording operation in a forward path and a return path of the reciprocating motion,
When printing black, only K ink is recorded in the forward path, and K is recorded in a recording position where K ink is already recorded in the return path in which the recording head is moved in the sub-scanning direction with respect to the forward path. An image forming apparatus that records ink other than the above. A recording head having a plurality of nozzles for discharging ink of colors other than K and K arranged in the main scanning direction, the recording head being reciprocated relative to the recording medium, An image forming method for printing black by an image forming apparatus that performs a recording operation in a return path,
An image forming apparatus that records ink other than K at a recording position shifted by a half pitch in at least one of a main scanning direction and a sub-scanning direction with respect to a K recording position during black printing.

Images