JP5950650B2 - Recording apparatus and recording method - Google Patents

Description

  The present invention relates to a recording apparatus and a recording method for forming an image by ejecting ink droplets onto a recording medium while scanning a recording head.

  Inkjet recording methods for recording on various recording media are capable of high-density and high-speed recording operations, and are therefore applied to and commercialized as printers or portable printers as output media for various devices. Yes. In this case, each recording apparatus has a configuration corresponding to the functions and usage patterns unique to these apparatuses.

  In general, an ink jet recording apparatus includes a carriage on which recording means (recording head) is mounted, a transport means for transporting a recording medium, and a control means for controlling these. The recording head for ejecting ink droplets from a plurality of ejection openings is serially scanned in the direction (main scanning direction) orthogonal to the transport direction (sub-scanning direction) of the recording medium, and the recording medium is equal to the recording width when not recording. Intermittent conveyance with the amount. This recording method performs recording by ejecting ink onto a recording medium according to a recording signal, and is widely used as a quiet recording method with low running cost. In recent years, many products applied to a recording apparatus capable of recording an image in color using a plurality of colors of ink have been put into practical use.

  When the inkjet recording method is applied to a color recording apparatus, the configuration of the recording head is roughly divided into two types. The first is a recording head in which a large number of nozzles that eject ink are arranged in a straight line in the sub-scanning direction. In this arrangement, nozzle rows C, M, and Y for ejecting yellow, magenta, and cyan inks are arranged in one row in the sub-scanning direction so that the nozzles corresponding to the respective colors do not overlap. In this recording head configuration, each color image is formed at different positions on the recording medium by one main scanning of the recording head. Therefore, when forming so-called secondary colors such as blue, red, and green, the order in which colors are superimposed is the same regardless of the scanning direction of the recording head. For example, when forming a blue image, after cyan is recorded, magenta is superimposed on the cyan and recorded. In this way, in a recording head in which a large number of nozzles are arranged in a straight line in the sub-scanning direction, secondary colors are formed in the same color order, so color unevenness due to a difference in ink recording order does not occur. .

  However, in the case of a recording head in which a large number of nozzles are arranged in a straight line in the sub-scanning direction, if the number of nozzles corresponding to each color is increased in order to speed up the recording process, recording is performed by the number of nozzles of each color. The head becomes long. As a result, the recording head itself, the carriage on which the recording head is mounted, and the like are also increased in size, which increases the cost of the recording apparatus.

  The second is a recording head in which nozzles C, M, and Y that discharge cyan ink (C ink), magenta ink (M ink), and yellow ink (Y ink) are arranged side by side in the main scanning direction. In the case of this recording head configuration, when forming images (bidirectional recording) by alternately repeating forward scanning and backward scanning in one-pass recording, for example, when forming so-called secondary colors of blue, red, and green, ink The recording order is different between forward scanning and backward scanning. Although depending on the type of the recording medium, the ink recorded earlier remains on the surface layer of the recording medium, and the ink recorded later tends to penetrate into the recording medium. Therefore, for example, when a red image is formed, in an area recorded in the order of “magenta → yellow”, magenta is present on the surface layer of the recording medium, so that it appears red from magenta. On the other hand, in the area recorded in the recording order of “yellow → magenta”, it looks red from yellow. As described above, when the ink recording order is different between the forward scan and the backward scan, the color (hue) is different in each scan, resulting in color unevenness and greatly reducing the image quality.

  Similarly, in the two-pass printing, first, the lower half nozzle of the print head is used in the first print scan, and the image is printed with a duty of about 50% in the print order of “magenta → yellow”. Next, the recording medium is conveyed by a distance that is half the head width, and the remaining 50% duty recording is performed in the recording order of “yellow → magenta” in the upper half of the head. By repeating this alternately, the entire image is recorded. In the forward scan and the reverse scan of the recording head, “the order of recording of magenta ink and yellow ink is different, so color unevenness may occur for each band that is half the recording head width. Color unevenness occurs between an area recorded in the recording order of “magenta → yellow → yellow → magenta” and an area recorded in the recording order of “yellow → magenta → magenta → yellow”.

  Compared with the case of 1-pass printing (difference in color between areas A and B), the degree of color unevenness (color difference between areas C and D) in the case of 2-pass printing is mixed in the recording order. As a result, the average is reduced. In addition, when the number of recording methods is further increased as 4-pass printing and 8-pass printing, the color unevenness becomes less noticeable. However, when the number of passes is increased, the number of recording scans required to complete an image increases, and the recording speed becomes slow. In order to perform high-speed recording, it is necessary to perform low-pass recording with a smaller number of recordings. However, in low-pass recording, color unevenness due to the recording order appears remarkably.

  In Patent Document 1, in two-pass printing, the direction and amount of printing medium conveyance performed between the forward printing scan and the backward printing scan are controlled, so that the order of overlapping of the inks in the reciprocating printing scan is made uniform. Yes. As a result, color unevenness caused by the order in which the inks are stacked (recording order) as described above is suppressed.

Japanese Patent No. 3176130

  According to the method disclosed in Patent Document 1, color unevenness due to the recording order of ink can be eliminated. However, the recording medium may be transported in the direction opposite to the direction in which the recording medium is ejected (conveyance direction) between the forward recording scan and the backward recording scan. In this case, depending on the conveyance amount in the reverse direction, the recording unit (the portion where the recording is performed) of the recording medium may be pulled back beyond the conveyance roller. When the recording medium (for example, paper) is in a wavy state (cockling) due to the ink adhering to the recording medium, the paper may be jammed by being conveyed in the reverse direction. In addition, when ink with low fixability is used, the ink adhering to the recording unit adheres to the conveyance roller or other members, and the ink is transferred again from these members to the recording medium, and the recording medium becomes dirty. The problem that it ends up also arises.

  Accordingly, the present invention provides a recording apparatus and a recording method including sending a recording medium in a direction opposite to the conveyance direction during a recording operation, and the recording apparatus and the recording capable of preventing a paper jam or contamination due to ink transfer. It aims to provide a method.

A recording apparatus according to the present invention includes a conveyance roller for conveying a recording medium,
Arranged in the conveying direction of the recording medium downstream of the conveying roller, and a carriage that reciprocates in a direction intersecting the transport direction of the recording head is mounted for ejecting ink, while moving the carriage in the forward direction A first recording control for recording an image on a recording medium by the recording head; a second recording control for recording an image on the recording medium by the recording head when the carriage is moved in the backward direction; in the the transport control for conveying the recording medium in the opposite direction of the conveying direction, and control means for, Ru with a recording device between the second recording control and the first recording control, said control means based on the number of pixels ink is ejected in a particular area, the amount of ink discharged from said recording head in said first recording control to said second recording control As less than the amount of ink discharged from the recording head have, to determine the ratio of the number of pixels to be recorded in the second recording control the number of pixels to be recorded in the first recording control Features.

The recording method according to the present invention includes a conveyance roller that conveys a recording medium and a recording head that is disposed downstream of the conveyance roller in the conveyance direction of the recording medium and that crosses the conveyance direction with a recording head that ejects ink A first recording step of recording an image on a recording medium by the recording head while moving the carriage in the forward direction; and A second recording step for recording an image on the recording medium by the recording head while moving in the backward direction, and the recording medium in the transport direction between the first recording step and the second recording step . anda transfer step of conveying in the opposite direction, based on the number of pixels ink is ejected in a particular region, or the recording head in the first recording step As the amount of ink discharged is smaller than the amount of ink ejected from the recording head in said second recording step, recording in the second recording step the number of pixels to be recorded in the first recording step A ratio with the number of pixels to be determined is determined .

  According to the present invention, it is possible to suppress recording medium conveyance failure (for example, paper jam) and contamination due to ink transfer.

1 is a schematic perspective view illustrating a configuration of an embodiment of a recording apparatus to which the present invention is applicable. 2 is a block diagram of a control circuit of a recording apparatus to which the present invention can be applied. FIG. It is a block diagram explaining the structure of the data processing which concerns on an Example. It is a schematic diagram for demonstrating two-pass bidirectional | two-way recording operation based on the Example of this invention. It is a schematic diagram which shows the structure of the recording device of an Example. FIG. 6 is a diagram for explaining mask data for recording ratio control according to the first exemplary embodiment. It is a schematic diagram for demonstrating the production | generation method of the recording data using mask data. 10 is a flowchart for explaining a recording ratio determination process according to the second embodiment. It is a schematic diagram for demonstrating the determination area | region in a recording ratio determination process. 10 is a recording ratio determination table in Embodiment 2. 10 is a flowchart illustrating a recording ratio determination process according to the third exemplary embodiment. 10 is a recording ratio determination table in Embodiment 3.

  Embodiments of a recording apparatus according to the present invention will be described below with reference to the drawings. First, an outline of a recording apparatus and a control system in this embodiment will be described.

(Outline of inkjet recording apparatus)
FIG. 1 is a schematic perspective view showing a configuration of an embodiment of an ink jet recording apparatus (for example, a printer) to which the present invention can be applied. The ink tanks 211 to 214 each contain ink (black, cyan, magenta, yellow), and are configured to be able to supply these four colors of ink to the recording heads 201 to 204. Hereinafter, black may be simply expressed as “K”, cyan may be simply expressed as “C”, magenta may be simply expressed as “M”, and yellow may be simply expressed as “Y”. The recording heads 201 to 204 are provided corresponding to four colors of ink, and are configured to be able to eject ink supplied from the ink tanks 211 to 214.

  The conveying roller (conveying means) 104 rotates while sandwiching the recording medium 107 together with the auxiliary roller 103, and conveys the recording medium 107 while facing the recording heads 201 to 204. Furthermore, the transport roller 104 and the auxiliary roller 103 also have a role of holding a recording medium (for example, recording paper) 107. The carriage is configured to be able to mount ink tanks 211 to 214 and recording heads 201 to 204, and is configured to be capable of reciprocating along the X direction in the figure while mounting these recording heads and ink tanks 211 to 214. Yes. During the reciprocation of the carriage, ink is ejected from the recording heads 201 to 204, thereby recording an image on the recording medium 107. At the time of non-recording such as during the recovery operation of the recording heads 201 to 204, the carriage is controlled to stand by at a home position h indicated by a dotted line in the drawing.

  The basic recording operation will be described below. Before the start of recording, when a recording start command is input, the recording heads 201 to 204 positioned at the home position h shown in FIG. 1 eject ink while moving in the X direction in FIG. An image is recorded in 107. Each of the recording heads 201 to 204 is provided with 128 nozzles (discharge ports) at regular intervals of 75 dpi. By this movement of the recording head once, recording is performed on an area having a width corresponding to the range of the nozzle array of the recording head. Before one recording scan (one operation from one end to the other end of the recording medium) ends and before the next recording scan starts, the transport roller 104 rotates and intersects the main scanning direction (in the figure). (Y direction or -Y direction), the recording medium is conveyed by a predetermined distance. Subsequently, the recording head discharges ink and records an image on the recording medium 107 while moving in the −X direction toward the home position h. In this way, recording is performed on the recording medium 107 by repeating the recording scan of the recording head and the conveyance of the recording medium. The detailed operation of recording will be described in the embodiment. A recording operation for ejecting ink from the recording heads 201 to 204 is performed based on control by a control unit described later.

(Outline of control system)
Next, the schematic configuration of the control system of the ink jet recording apparatus shown in FIG. 1 will be described with reference to the block diagram shown in FIG. The ink jet recording apparatus has a control unit 500. The control unit 500 is provided with an interface 400 for inputting a recording signal and a control signal related to recording, and an MPU (Micro Processing Unit) 401. Further, the control unit 500 is provided with a ROM (Read Only Memory) 402 for storing a control program executed by the MPU 401 and the like. Furthermore, even if a dynamic RAM (Dynamic Random Access Memory (DRAM)) 403 for storing various data (recording signals supplied to the recording heads 201 to 204, control signals for recording, etc.) is provided. good. It is preferable that the DRAM 403 can store the number of recording dots, the number of replacements of the recording heads 201 to 204, and the like. The gate array 404 that controls the supply of print data to the print heads 201 to 204 controls the transfer of data among the interface 400, MPU 401, and DRAM 403.

  The recording apparatus includes a carriage motor 406 for reciprocating a carriage on which the recording heads 201 to 204 are mounted in the main scanning direction, and a conveyance motor 405 for rotating the conveyance roller 104 for conveying the recording medium 107. The recording apparatus also includes motor drivers 408 and 407 for driving the transport motor 405 and the carriage motor 406, respectively. A plurality of head drivers 409 for driving the recording heads 201 to 204 are provided corresponding to the number of recording heads. The head type signal generation circuit 410 gives the MPU 401 a signal indicating the type and number of the recording heads 201 to 204 mounted on the head unit 501 corresponding to the carriage.

  FIG. 3 is a block diagram showing the flow of data processing in the recording device 1201. First, input multi-value RGB data 601 is transferred from the host PC 1200 (see FIG. 2) via the interface 400. In the recording apparatus 1201, conversion processing 602 from multi-value RGB data 601 to multi-value K data, C data, M data, and Y data 603 is performed. Multi-value K data, C data, M data, and Y data 603 are quantized into binary image data 604 (K data, C data, M data, Y data) by a predetermined quantization method. Finally, recording is performed by the recording heads 201 to 204 based on the quantized binary K data, C data, M data, and Y data 603. K data is data for recording K ink, C data is data for recording C ink, M data is data for recording M ink, and Y data is for recording Y ink. It is data.

Example 1
In the method according to the present embodiment, in the first recording scan immediately before the recording medium is sent in the direction opposite to the conveyance direction, the recording duty DUTY of the specific ink is lowered and the second after the recording medium is sent in the opposite direction. The recording DUTY is increased in the recording scan. FIG. 4 shows an example of an ink jet recording method according to Embodiment 1 of the present invention. FIG. 4 shows a two-pass bidirectional recording operation in which a recording medium conveyance operation in the conveyance direction and a recording medium conveyance operation in a direction opposite to the conveyance direction are combined. In the present specification, the “conveying direction” means a direction in which the recording medium is finally discharged.

  First, in the first recording scan, recording is performed on a recording medium while moving the recording heads 201 to 204 in one direction (X direction) using 64 nozzles in the lower half of the recording head. After the end of the first recording scan, the recording head is moved to the recording start position of the first recording scan. Next, the recording medium is conveyed in the Y direction by a distance corresponding to the width of 128 nozzles corresponding to the width of the recording head. Thereafter, in the second recording scan, recording is performed for the width of the recording head while moving the recording head in the X direction using all nozzles. Thereafter, the recording medium is conveyed in the -Y direction by the width of 64 nozzles corresponding to half the width of the recording head. Next, in the third recording scan, recording for the width of the recording head is performed while moving the recording head in the -X direction. In the third recording scan, ink is recorded so as to overlap where ink has already been recorded in the first recording scan and the second recording scan. Thereafter, the recording medium is conveyed in the Y direction by a width of 192 nozzles corresponding to 1.5 times the head width. In the fourth recording scan, recording for the recording head width is performed while moving the recording head in the X direction, and then the recording medium is conveyed in the -Y direction by the width of 64 nozzles. Next, in the fifth recording scan, recording is performed for the width of the recording head while moving the recording head in the -X direction. In the fifth recording scan, the ink is recorded in an overlapping manner where ink has already been recorded in the second recording scan and the fourth recording scan. Thereafter, the recording medium is conveyed in the Y direction by the width of 192 nozzles. In the sixth recording scan, recording is performed for the width of the recording head while moving the recording head in the X direction, and then the recording medium is conveyed in the −Y direction by the width of 64 nozzles. Next, in the seventh recording scan, recording is performed for the recording head width while moving the recording head in the −X direction, and then the recording medium is conveyed in the Y direction by the amount corresponding to the 192 nozzle width. In the eighth recording scan, recording is performed by half the width of the recording head while moving the recording head in the X direction using the nozzle corresponding to the upper half of the recording head. Thereafter, the recording medium is conveyed in the −Y direction by the width of 64 nozzles. In the ninth recording scan, recording is performed for the width of the recording head while moving the recording head in the -X direction. By repeating such a recording scan, all recording on the recording medium is completed.

  In the example shown in FIG. 4, the ink ejected from the recording head in the backward scanning (third, fifth, seventh and ninth recording scanning) is recorded in the forward scanning (first, second, fourth and sixth recording scanning). Overlaid ink. The recording heads 201 to 204 corresponding to the inks of the respective colors are provided side by side in the main scanning direction. Therefore, by performing printing by scanning in the forward direction on a recording medium that has been printed by scanning in the backward direction, it is possible to match the order in which the inks are superimposed. Specifically, for each recording band, the ink recording order can be aligned in the order of Y → M → C → K for the first pass and K → C → M → Y for the second pass.

  FIG. 5 is a schematic diagram for explaining the distance between the conveyance roller 104 and the nozzles configured in the recording heads 201 to 204. “W” in FIG. 5 indicates the width in the transport direction (hereinafter referred to as the nozzle area width) of the area in which the nozzles configured in the recording head are provided. In the present embodiment, it is 75 dpi. Corresponds to a width of 128 pixels. “L” in FIG. 5 represents the distance from the nozzle closest to the transport roller 104 to the transport roller 104. As shown in FIG. 5, the conveying roller 104 is preferably arranged on the upstream side in the conveying direction from the recording head. A long nozzle area width W is desirable from the viewpoint of increasing the area that can be recorded on the recording medium in one scan, but has the disadvantage that the recording apparatus becomes larger as the recording head becomes longer. When performing the two-pass bidirectional recording described with reference to FIG. 4, it is necessary to return the recording medium in the direction opposite to the conveyance direction immediately before the third, fifth, seventh and ninth recording scans. At this time, when the conveyance amount of the recording medium in the −Y direction exceeds the distance L, the recording unit to which the ink has already adhered is pulled back beyond the conveyance roller 104 when the recording medium is returned. . As a result, if the paper is in a undulated state due to ink recording, the undulated portion may pass through the conveying roller 104, thereby causing wrinkles or paper jams on the recording surface. In addition, when recording is performed with ink having low fixability, there is a problem that the ink adheres to the conveyance roller 104 or other members from the recording medium, and the ink adhered to these members contaminates the recording medium. End up.

  In the first embodiment, in response to the above-described problem when the recording medium is transported in the direction opposite to the transport direction, in the recording scan immediately before transport in the reverse direction, ink that easily generates cockling or specific ink with low fixability is used. Control to lower the recording ratio. The specific adjustment of the recording ratio of the specific ink is performed based on the data obtained by ANDing the quantized binary image data 604 and the mask data for each recording scan. The recording ratio refers to the ratio of the number of pixels to which ink should actually be applied to the area in each recording scan with respect to the area having a specific number of pixels.

  A1, A2, B1, and B2 shown in FIG. 6 show examples of mask data for recording ratio control. The size of the mask data corresponds to 8 × 8 pixels, and the black pixels in the drawing are ON, and the white pixels are OFF. The logical product of the binary image data and the mask data is calculated, and only the pixels that are turned ON are actually recorded by the recording scan. In FIG. 6, the masks A1 and A2 are configured such that 50% of the pixels are turned on. Further, the mask A1 and the mask A2 are complementary to each other. In other words, the pixels that are turned on at A1 are always turned off at A2, and the pixels that are turned off at A1 are set to be turned on at A2. In FIG. 6, about 30% of the pixels are ON in the ratio of the B1 mask, and about 70% of the pixels are ON in the ratio of the B2 mask. The mask B1 and the mask B2 are complementary to each other.

  FIG. 7 is a schematic diagram for explaining a method of generating K data and Y data for each printing scan using the mask data. In FIG. 7, the description will be made using only K data and Y data in order to simplify the description. In general, K ink is an ink with low fixing, and when the recording medium is fed in the −Y direction, there is a possibility that the K ink is transferred to a conveyance roller or other members. Y ink generally has good fixability, and even if the portion of the recording medium to which Y ink is attached comes into contact with the transport roller, there is little concern about transfer of Y ink to the transport roller.

  FIG. 7A and FIG. 7B are diagrams for explaining a method of generating Y data in consideration of the recording ratio. In FIG. 7A, the first recording data Y1 is generated by taking the logical product of the quantized binary Y data and the mask data A1. Similarly in FIG. 7B, the second print data Y2 is generated by taking the logical product of the quantized binary Y data and the mask data A2. By performing the above processing, print data for two-pass printing that completes printing in two printing scans can be generated. Since Y ink normally has no problem in fixing properties, it is preferable to use mask data A1 and A2 that have a recording ratio of 50% in the respective recording data Y1 and Y2.

  FIG. 7C and FIG. 7D are diagrams for explaining a method for generating K data in consideration of the recording ratio. In FIG. 7C, the first print data K1 is generated by taking the logical product of the quantized binary K data and the mask data B1. Similarly in FIG. 7D, the second print data K2 is generated by taking the logical product of the quantized binary K data and the mask data B2. Since K ink generally has a problem in fixing properties, it is preferable to generate recording data K1 and K2 having a recording ratio of about 30% and 70% different.

  In the first, second, fourth, sixth, and eighth print scans in FIG. 4, printing is performed based on the first print data Y1 and K1. On the other hand, in the third, fifth, seventh, and ninth recording scans, recording is performed based on the second recording data K2 and Y2. As described above, for the K ink, the recording ratio is reduced and the amount of ink adhering to the recording medium is reduced in the recording scan immediately before the recording medium is sent in the -Y direction. Thereby, when the recording medium is transported in the −Y direction, it is possible to suppress the K ink from being transferred to the transport roller and other members.

  On the other hand, since Y ink has no problem in fixing properties, recording can be performed at a recording ratio of 50% without changing the recording ratio in each recording scan. In the case of ink having no problem with fixing properties, it is basically desirable not to change the recording ratio from the viewpoint of suppressing streaks and unevenness. In the above example, the Y ink and the K ink have been specifically described. However, the present invention is not limited to this, and the ink for which the recording ratio should be changed may be appropriately determined according to the ink characteristics.

In the present embodiment, the method of changing the recording ratio according to the ink having different fixing properties has been described. Similarly, the recording ratio may be similarly changed for inks having different characteristics such as cockling characteristics that deform the recording medium by adhering to the recording medium. For example, when M ink has a characteristic that easily causes cockling, in the recording scan immediately before the recording medium is sent in the -Y direction, only the recording data of the M ink is set to decrease the recording ratio. That's fine. In this embodiment, in the recording scan immediately before the recording medium is sent in the -Y direction, the recording ratio is reduced to 30%. However, the recording ratio does not need to be 30%. What is necessary is just to set to an optimal ratio according to a ring characteristic.

  For extremely low fixability ink and ink that easily causes cockling, the recording ratio is set to 0 in the recording scan immediately before the recording medium is transported in the -Y direction, and 1-pass recording is performed. It doesn't matter. Two-pass printing is more desirable from the viewpoint of suppressing streaks and unevenness. However, if stains, wrinkles, or paper jams are likely to occur due to ink transfer, it may be set to perform one-pass printing.

  In the present embodiment, the conveyance amount of the recording medium in the direction opposite to the conveyance direction (−Y direction) is 64 nozzle widths. However, the conveyance amount is not necessarily limited to this, for example, 32 nozzles. The width may be set arbitrarily. If the recording medium is sometimes transported in the direction opposite to the transport direction (-Y direction) between one recording scan and another recording scan, the recording scan immediately before sending the recording medium in the -Y direction By reducing the recording ratio, problems such as ink transfer can be suppressed.

  Further, when the conveyance amount of the recording medium in the −Y direction exceeds the distance L from the nozzle closest to the conveyance roller 104 to the conveyance roller 104, a process for reducing the recording ratio (DUTY) of the specific ink may be performed. preferable. Whether the transport amount of the recording medium in the −Y direction exceeds the distance L when the transport amount of the recording medium in the direction opposite to the transport direction is changed for each type of recording medium and the recording mode. Therefore, it is more preferable to set whether or not to control the recording ratio. Ink transfer and cockling are greatly affected by the usage environment. Therefore, the recording ratio may be set to change depending on the usage environment such as the temperature and humidity of the recording place.

(Example 2)
In the second embodiment, a method of performing dot count of recording data and changing the rate of decrease in recording ratio according to the amount of ink that is driven into a predetermined area will be described. Other configurations are the same as those in the first embodiment.

  FIG. 8 is a flowchart illustrating the recording ratio determination process according to the second embodiment. First, in step S101, the number of dots in the determination area is counted. The determination area is an area corresponding to one block when binary KCMY data is divided into a plurality of blocks, and corresponds to a predetermined range of pixels. Counting the number of dots means counting the number of pixels of ink to be printed in this determination area, that is, the number of pixels that are turned on in binary image data. In this embodiment, the number of dots is counted for each ink type.

  Next, in step S102, the dot count value (number of dots) counted in step S101 is compared with a preset recording ratio determination table (see FIG. 10) to determine the recording ratio of one determination area. Next, in step S103, it is determined whether the processing has been completed for all determination regions. If the process has been completed for all the determination areas, the recording ratio determination process is terminated. If not, the process proceeds to the next determination area, and the processes in steps S101 to S102 are repeated. Thereby, the recording ratio can be determined for each determination area. The series of processing shown in FIG. 8 is preferably performed by a control unit provided in the recording apparatus.

  FIG. 9 is a schematic diagram for explaining a determination area of the recording ratio determination process. The determination area is an area corresponding to one block when the binary KCMY data is divided into a plurality of blocks. In this example, the size of one determination area is 8 × 8 pixels. In each determination region, each of 8 × 8 pixels is associated with ink ejection data “1” or non-ejection data “0”.

  FIG. 10 shows an example of a recording ratio determination table used when determining the recording ratio in step S102. The dot count value counted in step S101 is compared with this recording ratio determination table, and the recording ratio is determined for each determination area. For example, when the dot count value is 40, the recording ratio in the recording scan immediately before sending the recording medium in the −Y direction is reduced to 30%, and the recording ratio in the recording scan immediately after transporting the recording medium in the −Y direction is changed. Set to 70%. For example, mask data B1 and B2 shown in FIG. 6 can be used to realize the recording ratio immediately before and immediately after the recording medium is conveyed in the -Y direction. In the table shown in FIG. 10, when the number of dots in the determination area increases, the printing ratio in the printing scan immediately before sending the printing medium in the −Y direction is further reduced.

  As described above, the recording ratio is determined for each determination area, and based on the determined recording ratio, the data in which the recording ratio is changed for each determination area is generated using the mask data as described in the first embodiment. Recording may be executed based on the data.

  As described above, by changing the rate of decrease in the recording ratio based on the amount of ink that actually adheres to the recording medium, it is possible to more reliably prevent paper jams due to cockling and contamination due to ink transfer.

Example 3
In the third embodiment, a method of performing dot count of recording data for each ink of each color and changing the reduction rate of the recording ratio according to the amount of all ink recorded in the determination area will be described. Other configurations such as a recording method and a dot count method are the same as those in the first and second embodiments. The waviness of the recording medium due to cockling and the fixability of the ink largely depend on the total amount of ink recorded on the recording medium. Therefore, in this embodiment, the rate of decrease in the recording ratio is adjusted according to the total recording amount of ink recorded in the determination area.

  FIG. 11 is a flowchart illustrating the recording ratio determination process according to the third embodiment. First, in step S201, the number of ink dots in the determination area is counted. The number of dots is preferably counted for each ink. Subsequently, in step S202, the count value of each color dot multiplied by a predetermined coefficient (weight) is added to calculate a weighted total value Dt of the number of dots recorded in the determination area. Here, since cockling and fixability differ depending on the ink characteristics, it is preferable to multiply the count value of each color dot by a weighting coefficient corresponding to the ink characteristics. Depending on the ink characteristics, the sum of the count values of the respective color dots may be set to Dt without multiplying the weighting coefficient.

  Next, in step S203, the total value Dt is compared with a preset recording ratio determination table (see FIG. 12), and the recording ratio is determined for each determination area. Next, in step S204, it is determined whether or not the recording ratio determination processing has been completed in all determination areas. If the process has been completed for all the determination areas, the recording ratio determination process is terminated. If not, the process moves to the next determination area, and the processes of steps S201 to S204 are repeated. Note that the series of processing shown in FIG. 11 is preferably performed by a control unit provided in the recording apparatus.

  FIG. 12 is a recording ratio determination table used when determining the recording ratio in step S203. For example, when the total value Dt is 160, for black ink, the print ratio in the print scan immediately before sending the print medium in the −Y direction is reduced to 10%, and the print scan immediately after sending the print medium in the −Y direction. The recording ratio is set to 90%. For cyan, magenta, and yellow, the recording ratio in the recording scan immediately before transporting the recording medium in the -Y direction is reduced to 30%, and the recording ratio in the recording scan immediately after sending the recording medium in the -Y direction is set to 70%. Set. As described above, the recording ratio is determined for each determination area. As described above, by controlling the recording ratio based on the total recording amount of ink, when the recording medium is fed in the −Y direction, paper jamming due to cockling and contamination due to transfer can be further prevented.

  In this embodiment, the recording ratio is greatly changed for black ink rather than cyan, magenta, and yellow. The recording ratio for each ink is not limited to this, and may be appropriately determined in consideration of ink characteristics.

104 Conveying roller (conveying means)
107 Recording Medium 201-204 Recording Head 500 Control Unit 1201 Recording Device

Claims (9)

A transport roller for transporting the recording medium;
A carriage that is disposed downstream of the transport roller in the transport direction of the recording medium and that reciprocates in a direction that intersects the transport direction by mounting a recording head that ejects ink;
On the recording medium by said recording head when said first recording control for recording an image on a recording medium by a recording head, which moving the carriage in the backward direction while moving the carriage in the forward direction Control means for performing second recording control for recording an image, and transport control for transporting the recording medium in a direction opposite to the transport direction between the first recording control and the second recording control; in the recording apparatus Ru provided with,
Based on the number of pixels from which ink is ejected in a specific area, the control means ejects the amount of ink ejected from the recording head in the first recording control from the recording head in the second recording control. A recording apparatus, wherein a ratio between the number of pixels to be recorded in the first recording control and the number of pixels to be recorded in the second recording control is determined so as to be smaller than a predetermined ink amount.   The recording apparatus according to claim 1, further comprising a discharge unit that discharges a recording medium recorded by the recording head downstream of the recording head in the transport direction.   The control means determines a ratio between the number of pixels to be recorded in the first recording control and the number of pixels to be recorded in the second recording control based on the type of the recording medium. The recording apparatus according to claim 1 or 2.   The control means determines a ratio between the number of pixels to be recorded in the first recording control and the number of pixels to be recorded in the second recording control based on a use environment of the recording apparatus. The recording apparatus according to any one of claims 1 to 3. The recording head is configured to be capable of discharging a plurality of types of ink,
The control means counts the number of pixels from which each ink is ejected in a specific area from the recording data, and based on the total value of the number of pixels for each counted ink, the first recording control and the number of pixels to be recorded in the recording apparatus according to any one of claims 1 to 4, characterized in that to determine the ratio of the number of pixels to be recorded in the second recording control. The recording head is configured to be capable of discharging a plurality of types of ink,
The control means counts the number of pixels from which ink is ejected in a specific area from the recording data, and multiplies the counted number of pixels for each ink by a coefficient corresponding to the characteristics of each ink. based on the total value Te, the number of pixels to be recorded in the first recording control, claims 1 and determines the ratio of the number of pixels to be recorded in the second recording control 5 The recording apparatus according to any one of the above. The recording head is configured to be able to eject cyan, magenta, yellow, and black inks,
Wherein, for the black color of the ink, the ink amount ejected from the recording head in the first recording control, be less than the amount of ink ejected from the recording head in said second recording control the recording apparatus according to any one of claims 1 to 6, characterized in. The recording head is configured to be able to eject cyan, magenta, yellow, and black inks,
Said control means, for magenta ink, an ink amount ejected from the recording head in the first recording control, be less than the amount of ink ejected from the recording head in said second recording control the recording apparatus according to any one of claims 1 to 7, characterized in. A conveyance roller that conveys the recording medium; and a carriage that is arranged downstream of the conveyance roller in the conveyance direction of the recording medium and that reciprocates in a direction intersecting the conveyance direction with a recording head that discharges ink. A recording method using a recording apparatus,
A first recording step of recording an image on a recording medium by the recording head while moving the carriage in the forward direction;
A second recording step of recording an image on the recording medium by the recording head while moving the carriage in the backward direction;
A conveying step of conveying the recording medium in a direction opposite to the conveying direction between the first recording step and the second recording step;
Based on the number of pixels from which ink is ejected in a specific region, the amount of ink ejected from the recording head in the first recording step is greater than the amount of ink ejected from the recording head in the second recording step. A recording method comprising: determining a ratio between the number of pixels to be recorded in the first recording step and the number of pixels to be recorded in the second recording step so as to reduce the number .

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