JP2007185957A - Data processing method and ink-jet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a good recording image by reducing the visibility of the ink dots discharged on a recording medium for preliminary discharge when preliminary discharge is performed on the recording medium. <P>SOLUTION: Preliminary discharge data and image data are compared with each other. When preliminary discharge is performed on the pixels for which no image data is provided, the image data of the pixels adjacent to the pixels is detected. When image data is present, the image data is transferred to the pixels having preliminary data. Recording is performed while preliminary data is added to image data in each scanning. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a data processing method and an ink jet recording apparatus, and more particularly to a data processing method and a recording apparatus when preliminary ejection is performed on a recording medium.

  In an ink jet recording apparatus, recording is performed by discharging ink from a nozzle of a recording head toward a recording medium. Examples of such a recording head include a head that generates air bubbles by applying heat to the ink with a heater, and discharges ink with that pressure (see Patent Document 1), or a mechanical element that uses a piezo element. There are heads that eject ink.

  In a state where ink is not ejected from the ink ejection nozzle, the ink in the vicinity of the nozzle opening is promoted to evaporate water and the ink is thickened. Such ink thickening causes ejection failure such as bending of the ink ejection direction or insufficient ink ejection amount. In particular, when the opening diameter of the nozzle is small, this ejection failure is likely to occur. Further, ejection failure also occurs due to a cause such as minute paper dust or water droplets adhering to the nozzle opening.

  On the other hand, conventionally, in an ink jet recording apparatus, so-called preliminary ejection, which is ink ejection that does not participate in recording, is performed immediately before recording or outside recording paper at regular intervals during recording. As a result, the thickened ink is discharged, and the ejection failure can be solved in advance. In the method in which the carriage on which the recording head is mounted scans and records an image on the recording medium, the preliminary ejection is performed by moving the carriage to a predetermined location such as a waste ink absorber outside the recording medium.

  Further, as another preliminary ejection operation, preliminary ejection for ejecting ink not intended for image recording on a recording medium (hereinafter also referred to as “paper surface preliminary ejection”) is conventionally known (see Patent Document 2). . This preliminary ejection on the paper surface has particularly good ejection characteristics (hereinafter also referred to as “first-shot characteristics”) when a nozzle that has not been ejected according to the recording data performs the first ejection. It can also be used for intended purposes. The paper surface preliminary discharge is normally performed by one (one drop) discharge, and is performed at intervals corresponding to the degree of thickening.

JP 54-51837 A Japanese Patent Laid-Open No. 06-40042

  However, the paper surface preliminary ejection in the above-described conventional example is performed regardless of the position of the image recorded on the recording medium, since the ejection location and the number of times are determined in advance. For this reason, when dots (image dots) constituting an image and dots (preliminary ejection dots) formed by preliminary ejection on the paper surface are recorded on nearby pixels, these two dots may be mixed. Then, when these two dots are mixed, the density of the image increases, which may lead to image degradation.

  The present invention has been made to solve such a problem, and it is possible to reduce a density change caused by printing dots constituting an image and dots formed by preliminary ejection on a paper surface on neighboring pixels. An object of the present invention is to provide a data processing method and an ink jet recording apparatus.

In order to achieve the above object, the present invention provides a data processing apparatus for performing data processing for preliminarily ejecting ink from a recording head onto a recording medium, wherein image data does not exist and the pixels to be preliminarily ejected are processed. Determination means for determining whether or not the image data is present in neighboring pixels;
When it is determined that image data exists in the neighboring pixels, data processing is performed so that ink is not ejected to the neighboring pixels, and data processing is performed so that ink is ejected to the pixels to be preliminarily ejected. And a data processing means for performing data processing so that ink is ejected to the pixel to be preliminarily ejected when it is determined that there is no image data in the neighboring pixels.

  According to the above configuration, when there is no image data and image data exists in a pixel near the pixel to be preliminarily ejected, ink ejection is not performed on the neighboring pixel. On the other hand, for an image to be subjected to preliminary ejection, ink ejection is executed regardless of whether image data exists in the neighboring pixels. For this reason, it is possible to reduce the overlap between the preliminary ejection dots and the image dots in the vicinity thereof while performing the necessary preliminary ejection, and it is possible to reduce the change in the image density caused by the mixture of these two dots.

  In the present invention, when image data exists in a pixel that does not have image data and is in the vicinity of a pixel to be subjected to preliminary ejection, ink ejection is not performed on the neighboring pixel, and preliminary ejection is performed. Ink discharge is performed on the power pixel. This reduces the mixture of the preliminary ejection dots and the image dots in the vicinity thereof, and reduces the change in the image density caused by the mixture of these two dots. Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a perspective view showing an ink jet printer IJRA which is an embodiment of an ink jet recording apparatus according to the present invention. In the figure, the carriage HC carries an ink tank IT containing ink and an integrated ink jet cartridge IJC having a built-in recording head for discharging ink toward a recording medium P such as recording paper.

  The recording paper P is pressed against a platen 5000 that is rotatably provided by a paper pressing plate 5002 that is disposed to face the ink jet cartridge IJC. In the carriage HC, the rotation of the drive motor 5013 is engaged with the spiral groove of the lead screw 5005 with respect to 5004 via the driving force transmission gears 5009 to 5011. The carriage HC has a pin (not shown), is supported by the guide rail 5003, and reciprocates in the directions of arrows a and b.

  A lever 5006 is provided at one end in the movement direction of the carriage HC, and the presence of the lever 5006 is confirmed by two photocouplers 5007 and 5008 provided in the recording apparatus, and the rotation direction of the motor 5013 is switched. Detect home position.

  The carriage HC stops at the home position as necessary at the start of printing or during printing. At this home position, a cap member 5022 for capping the surface (discharge port surface) provided with the discharge ports of the ink jet recording head is supported by a support member 5016. Then, the suction recovery of the recording head is performed through the opening 5023 in the cap by a suction device 5015 that sucks the inside of the cap.

  The cleaning blade 5017 can be moved in the front-rear direction by a member 5019, and the main body support member 5018 supports them.

  The lever 5021 is a lever for starting suction for suction recovery. The lever 5021 moves with the movement of the cam 5020 engaged with the carriage HC, and the driving force from the driving motor is transmitted by a transmission mechanism such as clutch switching. Move controlled.

  FIG. 2 is a block diagram showing a control configuration for performing data processing in the present embodiment.

  Reference numeral 200 denotes a host device, 240 denotes a recording apparatus main body, 210 denotes an image controller, and 220 denotes a print engine. The image controller 210 stores recording data sent from the host as a reception buffer, and is used as a controller including a memory function for storing recording data in various image processing described later. In the recording apparatus main body 240, the MPU 221 controls each of the carriage drive system 223, the transport drive system 224, the recovery drive system 225, the print head drive system 226, and the like based on the program stored in the ROM α227. The RAM 228 is used as a work area for the MPU 221 or an area for temporarily storing data. Each control is performed via the ASIC 222, and reading / writing to the print buffer 229 and the mask buffer 230 is possible via the ASIC 222.

  The print buffer 229 is a buffer memory that temporarily stores recording data converted into a format that can be transferred to the recording head. In this embodiment, the print buffer 229 stores recording data for one scan of the head. The mask buffer 230 temporarily stores a mask pattern for multi-pass printing corresponding to the printing mode. When performing multi-pass printing, the print data actually recorded by the print head in each print scan is determined by the print data stored in the print buffer 229 and the mask pattern stored in the mask buffer 230. In the case of 1-pass printing, no mask pattern is necessary, and thus such processing is not performed.

  The ROM β 231 stores in advance a preliminary ejection pattern to be added to binarized print data. The MPU 221 can read the pattern data stored in the ROM β via the ASIC 222 and add a preliminary ejection pattern.

  Specifically, the recording operation is started when image data is input to the reception buffer of the image controller 210 from the host apparatus 200 connected to the outside of the recording apparatus main body 240. In addition to the recording data, the image data includes information necessary for recording such as recording quality and margin information. The print engine 220 analyzes the received image data and starts control corresponding to various information. At this time, recording data, recording quality, media, margin information, and the like are processed by the MPU 221 via the ASIC 222 and further stored in the RAM 228. This information is then referred to as appropriate in the necessary situation and used for process separation. Further, the recording mode is determined based on the recording quality and media information, and the mask pattern of the corresponding recording mode is read out from the ROM α 227 and written into the mask buffer 230.

  The recording data is multi-value data having density information at a stage where it is sent from the host device 200 and received by the image controller 210.

  When the print data for one scan is accumulated in the print buffer 229, the MPU 221 drives the transport drive system 224 via the ASIC 222 to feed the recording medium, and drives the carriage drive system 223 as necessary. Each recovery action is performed. When the carriage reaches a predetermined recording start position, the recording data held in the print buffer 229 is sequentially read in accordance with the ejection timing and transferred to the recording head through the recording head drive system 226.

  FIG. 3 is a block diagram showing the flow of data. Under the control of the MPU 221, the image controller 210 converts R, G, and B 8-bit data into R ′, G ′, and B ′ 8-bit data specific to the recording apparatus (color conversion processing 500). Next, R ′, G ′, B ′ 8-bit data is converted into C, M, Y, K 8-bit data (color separation processing 510). Next, 8-bit data of C, M, Y, and K is quantized into 4-bit data of C, M, Y, and K (quantization processing 520). Next, the 4-bit data of C, M, Y, and K is converted into 1-bit data (binary image data) of C, M, Y, and K using the index pattern (index development processing 530). In addition, the MPU 221 is used to add the preliminary paper ejection data, which will be described in detail later, to the binary image data so that the binary image data can be finally transferred to the recording head. At this stage, the data is stored in the print buffer 229. Written.

  FIG. 4 is a flowchart showing the flow of processing of the recording head 1 scan.

  In the image controller 210, binary image data of C, M, Y, K is generated from the R, G, B data (S110). Next, preliminary scan data for one scan is added to the binary image data (S115). Data with the preliminary ejection data added is transferred to the recording head, and recording is performed by scanning the recording head (S120).

  Next, a method for adding preliminary ejection data according to the first embodiment of the present invention will be described.

  Actually, since recording is performed at an image density of 1200 dpi on an A4 size recording medium, recording is performed for about 10000 × 16000 pixels per A4 size page. However, in order to simplify the illustration and description, A 16 × 16 pixel array will be described.

  FIGS. 5A to 5D are views showing a process of adding preliminary ejection data to image data of a 16 × 16 pixel array, and one of C, M, Y, and K recording heads. A process of adding preliminary ejection data of two recording heads is shown. Among these, FIG. 5A is a diagram showing binary image data. Here, “◎” means that the image data is ejection “1”, that is, the dots constituting the image are formed in the pixel. FIG. 5B is a diagram showing a pattern of preliminary ejection data (binary preliminary ejection data) stored in advance in the ROM β231. Here, “◯” means that the preliminary ejection data is ejection “1”, that is, a dot by preliminary ejection is formed on the pixel. FIG. 5C is a diagram for explaining the arrangement of the logical sum data of the data shown in FIG. 5A and the data shown in FIG. 5B and the process of performing the data processing of FIG. It is. According to such a logical sum process, even when the image data and the preliminary ejection data exist in the same pixel, only one dot is recorded in the pixel, and the dot constituting the image and the dot by the preliminary ejection are recorded. There is no overlap with the same pixel. That is, taking the logical sum of the image data and the preliminary ejection data means deleting either the image data or the preliminary ejection data. FIG. 5D is a diagram illustrating ejection data in which ink is actually ejected from the recording head after the data processing illustrated in FIG. 6 is performed.

  FIG. 6 is a flowchart illustrating processing for adding preliminary ejection data according to the present embodiment.

  In the following, when the main scanning direction of the recording head is x and the sub-scanning direction (nozzle arrangement direction of the recording head) is y, the image data for one scan shown in FIG. “15” in FIG. 5, and 0 to Ymax (“15” in FIG. 5) in the y direction. In addition, the image data at the pixel position (x, y) in the image data shown in FIG. 5A is indicated by A (x, y), and the pixel position (x, y) in the preliminary ejection pattern shown in FIG. The preliminary ejection data is indicated by B (x, y). This preliminary ejection data corresponds to a pixel scheduled to perform preliminary ejection. Similarly, the logical sum data shown in FIG. 5C is indicated by C (x, y), and the ejection data shown in FIG. 5D is indicated by D (x, y). In the process shown in FIG. 6, in the x direction, the addition of preliminary ejection data is examined pixel by pixel from x = Xmax to x = 0, and the process in the y direction is changed from y = 0 to y = Ymax. Then, it is determined to add preliminary ejection data to the entire data for one scan while sequentially increasing one pixel.

  First, in step S1 and step S2, y = 0 and x = Xmax are set. That is, the first pixel to be processed is determined.

  Next, in step S3, it is determined whether or not the pixel to be processed has preliminary ejection data (“◯” mark: “1”) in the pattern shown in FIG. That is, if B (x, y) = 0, there is no preliminary ejection data in the target pixel, so there is no need to perform preliminary ejection, and the process proceeds to step S16 to move to the processing of the pixel at the next coordinate.

  On the other hand, if B (x, y) = 1 in step S3, the process proceeds to step S4. In step S4, it is detected whether there is image data in the target pixel. When A (x, y) = 1, that is, when image data (“（” mark: “1”) exists, the process proceeds to step S16, and the process of the pixel of the next coordinate is performed. Note that the fact that A (x, y) = 1 is determined in step S4 means that image data and preliminary ejection data exist in the processing target pixel. Even in this case, the dots constituting the image (image dots) and the preliminary ejection dots (preliminary ejection dots) do not overlap at this pixel. This is because the logical sum of the image data and the preliminary ejection data is executed. As described above, according to the present embodiment, since the image dots and the preliminary ejection dots do not overlap with each other in the same pixel, it is possible to suppress an increase in density that occurs when these dots overlap.

  For example, as shown in FIG. 5, in the pixel of (x, y) = (3, 1), image data and preliminary ejection data exist, and A (3, 1) = 1, B (3, 1) = 1. In such a case, since image data exists in pixels that require preliminary ejection, C (3,1) = 1 is set with the image data as it is. As a result, the ejection data D (3, 1) = 1.

  If it is determined in step S4 that A (x, y) = 0, the process proceeds to step S5. Here, it is determined whether or not there is image data from the pixel (X + 1) next to the target pixel to the right direction Xmax.

  That is, when there is no image data in the pixels after the target pixel in the main scanning direction of the recording head, it is no longer necessary to perform preliminary ejection on the paper in consideration of the first-shot characteristics because the recording is no longer performed in the scanning. That is, after the pixel, without performing preliminary discharge, the limit distance (time) at which the first characteristic described later deteriorates may be exceeded, and the first characteristic may actually deteriorate. However, the deterioration of the first-shot characteristics is not so small as ejection failure but is relatively slight. From this point, in this embodiment, no special processing is performed for the deterioration of the characteristics. This characteristic deterioration is recovered by discharge or preliminary paper discharge for recording in the next scan (although these discharges themselves are deteriorated in the first characteristic). Of course, normal preliminary discharge corresponding to a more serious discharge failure is performed separately. For example, the normal preliminary ejection may be performed by moving to a place outside the recording medium every predetermined number of scans, and this configuration is effective particularly when recording on a large sheet.

  Thus, when it is determined in step S5 that there is no image data between A (x + 1, y) and A (Xmax, y), the preliminary ejection data B (x, y) = 1 is deleted and C ( x, y) = 0 (“X” in “◯” in FIG. 5C). As a result, the final ejection data is D (x, y) = 0 (S15).

  For example, as shown in FIG. 5, when (x, y) = (8, 0) or (x, y) = (10, 14), B (x, y) = 1, but (8 + 1, 0 ) To (15, 0) or between (10 + 1, 14) to (15, 14), there is no image data A (x, y) = 1. In such a case, in step S15, C (x, y) = 0 is set, the preliminary discharge data of the target pixel is deleted, and the discharge data becomes D (x, y) = 0. In this way, step S5 is a step for determining this pixel based on the image data in order to exclude pixels that do not need to be preliminarily ejected from the pixels scheduled to be preliminarily ejected.

  If it is determined in step S5 that there is image data, the process proceeds to step S6. In step S6, it is necessary to perform preliminary ejection with respect to the first-shot characteristics in which the pixel L has image data among pixels before and after the target pixel in the x direction, that is, the interval L between the pixels where A (x, y) = 1. It is determined whether or not it is larger than the interval Lmax. That is, even if the target pixel is a pixel for which preliminary ejection is to be performed (a pixel of B (x, y) = 1), an interval (L that does not deteriorate the first-time characteristics before and after the pixel in the main scanning direction) In the case of <Lmax), the first discharge characteristic by the subsequent image data is not deteriorated. For this reason, in order to prevent preliminary discharge from being performed on the target pixel, the preliminary discharge data B (x, y) = 1 is deleted in step S15 and C (x, y) = 0 is set. As a result, the ejection data becomes D (x, y) = 0. When detecting the interval L, if there is no image data in the pixel on the left side (front) in the x direction, the interval L includes the number of pixels up to the processing target pixel including the pixel of x = 0.

  In the present embodiment, the number of pixels Lmax that must be preliminarily ejected is Lmax = 8. Therefore, in step S6, if the relationship with the number L of pixels having no image data before and after the target pixel is L <Lmax, C (x, y) = 0 in step S15, and the ejection data is D (x, y) = 0. As described above, step 6 is a step of determining the pixels based on the image data in order to exclude pixels that do not need to be preliminarily ejected from the pixels scheduled to be preliminarily ejected.

  On the other hand, if it is determined in step S6 that the image data has a certain interval L ≧ Lmax in the pixels before and after the target pixel in the X direction, the process proceeds to step S7. In step S7, it is determined whether there is image data in predetermined four pixels adjacent to the processing target pixel (x, y). The four pixels adjacent to the target pixel are A (x-1, y-1), A (x, y-1), A (x + 1, y-1), and A (x + 1, y), respectively. If there is no image data in these four pixels, D (x, y) = 1 is set in step S14. That is, when there is no image data in a pixel adjacent to a pixel to be preliminarily ejected, data processing is performed so that ink is ejected to the pixel to be preliminarily ejected.

  For example, in the target pixel (6, 10), B (6, 10) = 1, but in the four neighboring pixels of the pixel (6, 10), A (5, 9) = 0, A (6, 9 ) = 0, A (7,9) = 0, A (7,10) = 0, and there is no image data. Accordingly, preliminary ejection is performed on the target pixel (x, y) = (6, 10), and final ejection data is D (x, y) = 1.

  On the other hand, when there is image data in predetermined four adjacent pixels, the data moving from step S8 to step S12 is detected.

  In step S8, adjacent image data candidates are set. Here, it is assumed that a candidate for movement data among the four adjacent pixels is A (X, Y). That is, when the pixel of the candidate data is (x-1, y-1), X = x-1, Y = y-1. In the next step S9, it is determined whether or not image data exists from A (X + 1, Y) to A (Xmax, Y). If there is no image data, the image data of the adjacent pixel A (X, Y) is moved to the target pixel (x, y). That is, C (X, Y) = 0 is set in the pixel (X, Y), the final ejection data is set as D (X, Y) = 0 (step S13), and D is set in the target pixel (x, y). (x, y) = 1 is set (step S14).

  If image data exists from A (X + 1, Y) to A (Xmax, Y) in step S9, the same determination as in step S6 is performed. That is, it is determined whether or not the interval L ′ between the pixels including the adjacent pixel (X, Y) where the image data exists is larger than the interval Lmax at which the preliminary ejection must be performed (step S10).

  If the relationship between the number L ′ of no image data before and after the adjacent pixel is L ′ <Lmax, the image data A (X, Y) = 1 of the adjacent pixel is moved to the target pixel (x, y). . That is, it is set so that ink ejection is not performed on adjacent pixels, and ink ejection is performed on target pixels that should be subjected to preliminary ejection. Specifically, C (X, Y) = D (X, Y) = 0 is set (step S13), and D (x, y) = 1 is set (step S14). In the present embodiment, the “movement of image data” described above is realized by “deletion of image data” and “logical OR of image data and preliminary ejection data”.

  For example, in the target pixel (8, 8), A (8, 8) = 0, B (8, 8) = 1, and L ≧ Lmax, so the process proceeds to step S7. Since there is image data at (8, 7) among the predetermined four adjacent pixels, the candidate for the movement data is A (8, 7). In step S9, it is determined whether image data exists from A (X + 1, Y) to A (Xmax, Y). As a result, image data exists in (15, 7) between A (9, 7) and A (15, 7). Accordingly, the process proceeds to step S10. Here, if it is determined whether L ′> Lmax, the interval between the pixels including the image data in the preceding and following pixels including (8, 7) is larger than the interval Lmax at which the preliminary ejection must be performed. Is detected (step S11). Since there is no image data in other predetermined adjacent pixels serving as candidate data, D (8,8) = 1 is set (step S14), and the process proceeds to the next target pixel. As described above, when image data is present in an adjacent pixel of a pixel to be subjected to preliminary ejection, data processing is performed so that ink ejection is not performed on the adjacent pixel, and ink ejection is performed on a pixel to be preliminary ejected. Perform data processing.

  On the other hand, if L ′ ≧ Lmax, it is detected whether there is other moving data (S11). If there is data, it is determined whether data is moved from step S9 through step S12. To do. By moving the image data of adjacent pixels as preliminary ejection data in this way, local changes in density that can occur when preliminary ejection data is recorded adjacent to image data can be reduced.

  On the other hand, if there is no data in step S11, the preliminary ejection data B (x, y) = 1 is reflected as it is, and D (x, y) = 1.

  For example, in (x, y) = (11, 9), A (11, 9) = 0 and B (11, 9) = 1. Then, predetermined adjacent four pixels A (10,8) = 0, A (11,8) = 0, A (12,8) = 1, and A (12,9) = 1. Here, although A (12,8) = 1 and A (12,9) = 1, the moving data is determined by giving priority to the image data of (12,8) searched earlier according to the data search order. is doing. The image data of (12, 8) is moved to (11, 9), D (12, 8) = 0 is set (step S13), and D (11, 9) = 1 is set (step S14).

  In addition, when there are a plurality of image data in predetermined four adjacent pixels, the data determination method is not limited to the above method. For example, the movement data may be determined based on the amount of other peripheral pixels, and other methods may be used as the data determination means.

  The above steps S3 to S15 are performed for all the pixels in the x direction (S16). When there are no more pixels in the x direction (S17), the process advances by one pixel in the y direction (S18). When all pixels in the y direction are finished (S19), the step of adding preliminary ejection data is finished. In FIG. 6, the image data of neighboring pixels is moved to the preliminary ejection position in order to perform ink ejection at the preliminary ejection position and not to eject ink near the preliminary ejection position. However, in this embodiment, preliminary ejection data is prepared in advance, so that it is possible to eject ink to the preliminary ejection position and perform preliminary ejection only by deleting the image data without moving the image data of neighboring pixels. It can be realized that ink is not ejected in the vicinity of the position. Therefore, such a configuration is also included in the present embodiment. In this case, instead of executing “movement of image data”, “deletion of image data of neighboring pixels” and “OR operation of image data and preliminary ejection data” may be executed.

  The ejection data generated by the above steps is sent to the print buffer 229.

  FIG. 7 is a block diagram showing the contents of the print buffer. As shown in the figure, the print buffer has a capacity for one scan of the head, and the inside of the print buffer capacity 202 is divided into 10 blocks 203 to 212. When a certain amount of data is accumulated in the internal capacity of the print buffer, the MPU 221 starts the recording medium feeding operation by the transport driving system 224 via the ASIC 222. Then, the carriage is moved by the carriage drive system 223 and is restored by the recovery drive system 225 as necessary to perform a necessary recovery operation before recording. Then, an image output position or the like is set to the ASIC 222, and a recording operation is started. When the carriage moves and reaches the recording start position, the recording data stored in the print buffer is sequentially read in accordance with the ejection timing, and recording is performed by transferring the ejection data to the recording head.

  By repeating the above series of operations, images are sequentially formed on the recording medium.

  As described above, when image data exists in a pixel near the preliminary ejection position where no image data exists, data processing is performed so that ink ejection is not performed on the neighboring pixel. For example, the image data of neighboring pixels is deleted. On the other hand, data processing is performed so that ink ejection is performed at the preliminary ejection position regardless of whether image data exists in the neighboring pixels. According to this, it is possible to suppress mixing of the preliminary ejection dots and the image dots in the vicinity thereof while performing the necessary preliminary ejection. As a result, it is possible to reduce density changes caused by mixing image dots and preliminary ejection dots.

  In addition, this embodiment is not restricted to the form which performs all the processes (step S1-S19) shown in FIG. 6, It is also possible to abbreviate | omit a part of process. For example, as described above, the feature of the present embodiment is that, when image data exists in a pixel near the preliminary ejection position where no image data exists, the image data of the neighboring pixel is deleted (moved). Therefore, processes that do not correspond to the feature items themselves, for example, processes such as steps S5, S6, and S15, may be omitted. However, when steps S5 and S6 are not executed, the pixels that are scheduled to perform preliminary ejection become “pixels that should perform preliminary ejection”, and the number of preliminary ejection dots is relatively large. On the other hand, when steps S5 and S6 are executed, pixels that are determined to be not required to be preliminarily ejected based on image data out of pixels scheduled to be preliminarily ejected are “pixels to be preliminarily ejected”. Therefore, the number of preliminary ejection dots can be reduced.

  In the present embodiment, a part of the process (steps S1 to S19) illustrated in FIG. 6 can be replaced with another process. For example, in step S7, the data candidate to be moved (deleted) is selected from the pixels adjacent to the preliminary ejection position. However, the present invention is not limited to this mode. In selecting a data candidate to be moved (deleted), it may be configured to select from pixels (adjacent pixels) that are not adjacent to the preliminary ejection position but exist within several pixels from the preliminary ejection position.

(Embodiment 2)
In the first embodiment, preliminary ejection data is stored in advance in a ROM, and binary ejection data is created based on preliminary ejection data and image data read from the ROM. However, in the second embodiment, the preliminary discharge data is not created in advance, and the discharge data is created by adding the preliminary discharge data while referring to the image data. The same applies to the second embodiment in that when image data exists in a pixel near the preliminary ejection position where no image data exists, data processing is performed so that ink ejection is not performed on the neighboring pixel. .

  FIG. 8 is a block diagram showing a control configuration for performing image processing in the present embodiment. 2 is the same as the control configuration shown in FIG. 2 described in the first embodiment except that it does not have a ROM β that preliminarily stores paper preliminary ejection data.

  Here, a method for adding preliminary ejection data according to the second embodiment of the present invention will be described.

  Hereinafter, in the same manner as in the first embodiment, a 16 × 16 pixel array will be described in order to simplify the illustration and description.

  FIGS. 9A to 9C are diagrams showing a process of adding preliminary ejection data to image data of a 16 × 16 pixel array, and one of C, M, Y, and K recording heads. A process of adding preliminary ejection data of two recording heads is shown. Among these, FIG. 9A shows image data. Here, “◎” means that the image data is ejection “1”, that is, a dot is formed in the pixel. FIG. 9B is a diagram for explaining the arrangement of data with preliminary ejection data added to FIG. 9A and the process of performing the data processing of FIG. FIG. 9C is a diagram illustrating ejection data in which ink is actually ejected from the recording head after the data processing illustrated in FIG. 10 is performed.

  FIG. 10 is a flowchart showing processing for adding preliminary ejection data according to the present embodiment.

  Hereinafter, as in the first embodiment, when the main scanning direction of the recording head is x and the sub-scanning direction (nozzle arrangement direction of the recording head) is y, the image data for one scan shown in FIG. The direction is 0 to Xmax (“15” in FIG. 9), and the direction is 0 to Ymax (“15” in FIG. 9). In the image data shown in FIG. 9A, the image data at the pixel position (x, y) is indicated by A (x, y), and the data shown in FIG. 9B is indicated by C (x, y). Further, the discharge data shown in FIG. 9C is indicated by D (x, y).

  In the process shown in FIG. 10, in the x direction, the addition of preliminary ejection data is examined pixel by pixel from x = 0 to x = Xmax, and the process in the y direction is changed from y = 0 to y = Ymax. Then, it is determined to add preliminary ejection data to the entire data for one scan while sequentially increasing one pixel.

  First, in step S201, y = 0, x = 0, and L = 0. That is, the first processing target image is determined.

  Next, it is determined whether there is image data (“◎” mark: “1”) in the pixel to be processed (S202). If image data exists, D (x, y) = 1 is set, L = 0 is set in step S212, and the process moves to the pixel processing of the next coordinate. If there is no image data in the target pixel, it is determined whether L ≧ Lmax (S203).

  In this embodiment, the interval at which image data exists between pixels before and after the target pixel in the X direction is L, and the number of pixels Lmax for which preliminary ejection must be performed is Lmax = 8. Therefore, in step S203, if L ≧ Lmax, the process proceeds to step S204. On the other hand, if the interval L <Lmax that does not cause deterioration of the first characteristic, L = L + 1 is set in step S215, and the process moves to the pixel processing of the next coordinate.

  In step S204, it is determined whether there is image data in the right direction Xmax from the target pixel. If there is image data, it is necessary to perform preliminary ejection on the processing target pixel, and the process proceeds to step S205. On the other hand, if it is determined in step S204 that there is no image data, it is not necessary to perform preliminary ejection on the pixel line, so it is determined whether there is another line to be processed (step S214). If it is determined that there are other processing target lines, the processing target is moved to the next pixel line (step S217). For example, in the target pixel (11, 1), L = Lmax = 8, but since there is no image data in the pixels (12, 1) to (Xmax, 1) in the main scanning direction, D (11, 1 1) = 0, and the process target is moved to the next pixel line through S217.

  In step S205, it is determined whether there is image data in a pixel near the processing target pixel. Here, as described in step S <b> 204, the processing target pixel in step S <b> 205 is a pixel that needs to be subjected to preliminary ejection. Therefore, in this step S205, it is determined whether or not image data exists in a pixel in the vicinity of the preliminary ejection position where no image data exists. In the present embodiment, the pixels near the target pixel are changed from (x−L, y−1) to (x, y−1) in the main scanning direction. When there is no image data in these neighboring pixels, data movement from the neighboring pixels is not possible, so that D (x, y) = 1 is set in step S211, and preliminary ejection data is added to this processing target pixel. On the other hand, if there is image data from (x−L, y−1) to (x, y−1), the data moving from step S206 to step 209 is detected.

  In step S206, image data candidates are set from the above-mentioned neighboring image data. A candidate for moving data is A (X, Y). In the next step S207, it is determined whether or not the interval between the pixels in which the image data exists in the previous and subsequent pixels including the image data A (X, Y) of the neighboring pixels is larger than the interval L at which the preliminary ejection must be performed. . If the pixel interval is less than L, the image data A (X, Y) of the neighboring pixel is moved to the target pixel (x, y). That is, C (X, Y) = D (X, Y) = 0 is set (S210), and D (x, y) = 1 is set (S211). As described above, by moving the image data of the neighboring pixels to the processing target pixel, it is possible to perform preliminary ejection on the processing target pixel. In S212, L = 0, and the process moves to the pixel processing of the next coordinate.

  On the other hand, if the pixel interval is greater than or equal to L in S207, it is detected whether there is another moving data candidate (S208). If there is data, the same goes for the next moving data candidate through S209. Process. As described above, according to steps S207 to S209, the preliminary ejection at a necessary position is enabled by moving the image data of the pixels near the preliminary ejection position where no image data exists to the preliminary ejection position. This “movement of image data” is realized by deleting image data and adding preliminary ejection data.

  For example, in (x, y) = (10, 5), A (10, 5) = 0 and L = 8. Then, in the pixels (x, y) = (2, 4) to (10, 4) in the vicinity of the processing target pixel, A (6, 4) = A (7, 4) = A (8, 4) = A (9,4) = A (10,4) = 1. Then, (10, 4) image data whose x value is closest to the x value of the processing target pixel is preferentially determined as a candidate for moving data. Since the interval between the pixels in which the image data of the previous and subsequent pixels including the image data A (10, 4) that is the movement candidate exists is 0, the image data of (10, 4) is changed to (10, 5). Moving. Then, D (10, 4) = 0 is set (S210), and the image data D (10, 5) moved from D (10, 4) is set to 1 (S211).

  Note that, when there are a plurality of image data in neighboring pixels, which image data is preferentially processed is not particularly limited.

  The processes from step S210 to step S212 are performed for all the pixels in the x direction (S216). When there are no more pixels in the x direction (S213), the process proceeds by one pixel in the y direction (S217). When all the pixels in the y direction are finished (S214), the step of adding preliminary ejection data is finished.

  As described above, in the present embodiment, when image data exists in a pixel in the vicinity of the preliminary ejection position where no image data exists, data processing is performed so that ink is not ejected to the neighboring pixel. On the other hand, at the preliminary ejection position, data processing is performed so that ink is ejected regardless of whether image data exists in the neighboring pixels. This makes it possible to reduce the overlap between the preliminary ejection dots and the image dots while performing the necessary preliminary ejection, and to reduce the density change of the image that occurs when these two dots coexist.

(Embodiment 3)
In the first and second embodiments, the printer buffer 229 has a memory capacity for one scan. However, the printer buffer 229 has a memory capacity of less than one scan, for example, a memory capacity that is half that of one scan. It may be.

  FIG. 11 is a block diagram showing the contents of the print buffer of this embodiment. As shown in the figure, the print buffer capacity 202 is divided into five blocks 203 to 207. When a certain amount of data is accumulated in the internal capacity of the print buffer, the MPU 221 starts the recording medium feeding operation by the transport driving system 224 via the ASIC 222. Each time reading is completed, the next block of data is saved and the memory is used in a toggle manner. In addition, since the memory capacity of the image controller is less than one scan, data for one scan is divided and data processing is sequentially performed.

  In this embodiment, since the image data up to the end of one scan cannot be referred to at the start of one scan, the print data is referred to by adding preliminary ejection data to the image data with reference to the image data within a limited block. create.

  Here, a method for adding preliminary ejection data according to the present embodiment will be described. Also in the third embodiment, as in the first and second embodiments, when image data exists in a pixel in the vicinity of the preliminary ejection position where no image data exists, the image data in the neighboring pixel is moved to the preliminary ejection position. To do.

  Hereinafter, as in the first and second embodiments, a 16 × 16 pixel array will be described for the sake of simplicity of illustration and description.

  12A to 12C are diagrams showing a process of adding preliminary ejection data to image data of a 16 × 16 pixel array, and one of the C, M, Y, and K recording heads. A process of adding preliminary ejection data of two recording heads is shown. Among these, FIG. 12A shows image data. Here, “◎” means that the image data is ejection “1”, that is, a dot is formed in the pixel. FIG. 12B is a diagram for explaining the arrangement of data with preliminary ejection data added to FIG. 12A and the process of performing the data processing of FIG. FIG. 12C is a diagram illustrating ejection data in which ink is actually ejected from the recording head after the data processing illustrated in FIG. 13 is performed.

  FIG. 13 is a flowchart illustrating processing for adding preliminary ejection data according to the present embodiment.

  Hereinafter, as in the first and second embodiments, the main scanning direction of the recording head is x, and the sub-scanning direction (nozzle arrangement direction of the recording head) is y. The image data and the like for one scan shown in FIG. 12 is set to 0 to Xmax (“15” in FIG. 12) in the x direction and 0 to Ymax in the y direction. In the image data shown in FIG. 12A, the image data at the pixel position (x, y) is indicated by A (x, y), and the data shown in FIG. 12B is indicated by C (x, y). Further, the discharge data shown in FIG. 12C is indicated by D (x, y).

  In the process shown in FIG. 13, in the x direction, the addition of preliminary ejection data is examined pixel by pixel from x = 0 to x = Xmax, and the process in the X direction is changed from y = 0 to y = Ymax. Then, it is determined to add preliminary ejection data to the entire data for one scan while sequentially increasing one pixel.

  In the present embodiment, processing similar to that in the second embodiment is performed, but the processing in step S205 is not performed. That is, even if there is no image data after the target pixel in the main scanning direction of the recording head, C (x, y) = D (x, y) = 0 is not set and a candidate for moving data is detected. (S304).

  Then, it is determined whether or not there is image data in predetermined four pixels adjacent to the processing target pixel (S304), and the image data that can be moved is moved (S305 to S310). Here, the predetermined four pixels are the same as the four pixels described in the first embodiment.

  FIG. 14 is a flowchart showing the flow of processing of one scan of the print head. Inside the divided print buffer, preliminary ejection data is added to the image data of blocks 203 to 207, and the recording data (ejection data) created thereby is input. Then, the recording head is scanned by sending such data to the recording head. If there is a block for which output has been completed, the process proceeds to processing of the next block data. When all the blocks have been processed, the recording head 1-scan process ends.

  With the above configuration, the present invention can be applied even when the memory capacity of the print buffer 229 is small. Therefore, regardless of the size of the memory capacity, image degradation of the image can be minimized by moving the image data of the pixels close to the position where the preliminary paper ejection is required.

(Other embodiments)
Embodiments 1 to 3 described above have described examples of paper surface preliminary ejection corresponding to so-called first-shot characteristics. Therefore, in each of the above-described embodiments, normal preliminary discharge for preventing discharge failure is performed separately from the paper surface preliminary discharge according to the embodiment of the present invention described for each scan. Of course, the application of the present invention is not limited to such a form. Instead of or in addition to the normal preliminary ejection that ejects ink outside the recording paper at regular intervals just before recording or during recording, the paper surface preliminary ejection is performed for the purpose of preventing general ejection defects. There may be.

  In such a case, the process of FIG. 6 can be realized basically by omitting the processes of steps S5 and S9. In this case, the parameters L and L ′ used in the determinations in steps S6 and S10 are obtained including the pixel rows to be recorded in the next and subsequent main scans.

  As a result, even in a configuration in which preliminary ejection is not performed outside the recording paper, it is possible to minimize image degradation by moving image data of pixels close to a position where preliminary ejection on the paper surface is necessary. .

  In the first to third embodiments described above, the case where the data processing for performing the preliminary ejection on the paper surface is performed in the recording apparatus has been described. However, the present invention is not limited to this form, and for example, a form in which the data processing is performed by a host device connected to the recording apparatus may be employed. In this case, the data processing is executed by the printer driver installed in the host device and the CPU of the host device. The apparatus that performs the data processing for performing the paper preliminary ejection in this way may be a recording apparatus or a host apparatus.

  In the first to third embodiments described above, the case of using a serial type printer that performs recording while moving (scanning) the recording head relative to the recording medium has been described. However, printers to which the present invention can be applied are limited to serial type printers. It is not something that can be done. The present invention is also applicable to a line type printer that uses a line head having a length over the entire width of the recording medium and performs recording while moving (conveying) the recording medium with respect to the line head. Thus, the present invention can be applied to a printer that performs recording while moving the recording head relative to the recording medium.

1 is a perspective view showing an ink jet recording apparatus according to an embodiment of the present invention. It is the block diagram shown about the control structure for performing the image processing concerning Embodiment 1 of this invention. It is a block diagram which shows the data flow of the recording device concerning Embodiment 1 of this invention. 4 is a flowchart showing a flow of processing of one scan of the recording head according to the first embodiment of the present invention. It is a figure which shows the example of the data position of a pixel. It is a flowchart which shows the process of adding the preliminary discharge data concerning Embodiment 1 of this invention. It is a block diagram which shows the content of the print buffer concerning Embodiment 1 of this invention. It is the block diagram shown about the control structure for performing the image process concerning Embodiment 2 of this invention. It is a figure which shows the example of the data position of a pixel. It is a flowchart which shows the process of adding the preliminary discharge data concerning Embodiment 2 of this invention. It is a block diagram which shows the content of the print buffer concerning Embodiment 3 of this invention. It is a figure which shows the example of the data position of a pixel. It is a flowchart which shows the process of adding the preliminary discharge data concerning Embodiment 3 of this invention. 10 is a flowchart showing a flow of processing of a recording head 1 scan according to a third embodiment of the present invention.

Explanation of symbols

HC Carriage IJH Recording head IT Ink tank IJC Ink cartridge
5005 Lead screw 5015 Suction device 5020 Cam 5022 Cap member 5021 Lever 5023 Inner opening

Claims (6)

A data processing apparatus for performing data processing for pre-discharging ink from a recording head onto a recording medium,
Determination means for determining whether or not the image data exists in a pixel in the vicinity of the pixel to be subjected to the preliminary ejection, in which no image data exists;
When it is determined that image data exists in the neighboring pixels, data processing is performed so that ink is not ejected to the neighboring pixels, and data processing is performed so that ink is ejected to the pixels to be preliminarily ejected. And data processing means for performing data processing so that ink is ejected to the pixels to be preliminarily ejected when it is determined that no image data exists in the neighboring pixels. apparatus.   When it is determined that image data exists in the neighboring pixels, the data processing unit deletes the image data of the neighboring pixels, and data for ejecting the ink to the pixels to be subjected to the preliminary ejection The data processing apparatus according to claim 1, wherein: is set.   The data processing apparatus further includes a memory that stores preliminary ejection data that defines pixels to be preliminarily ejected, and the pixels to be preliminarily ejected are determined according to the preliminary ejection data. The data processing apparatus according to claim 1.   The pixels to be preliminarily ejected are pixels excluding at least pixels determined not to be preliminarily ejected based on the image data among the pixels to be preliminarily ejected. The data processing apparatus according to claim 3.   The data processing apparatus according to claim 1, wherein the pixel to be preliminarily ejected is determined according to the image data. An ink jet recording apparatus capable of pre-discharging ink from a recording head onto a recording medium,
An ink jet recording apparatus comprising: the data processing apparatus according to claim 1; and a recording head for ejecting ink based on data processed by the data processing apparatus.

Images