JPH10315512A - Color image recorder and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the difference of color tone due to the difference of order for superposing the inks, when a color image is recorded of ink dots, by recording the adjacent dot positions with an ink color having high visual sensitivity it the adjacent dots are not recorded in such dots as at least two color inks are superposed. SOLUTION: After a data is stored in the first row of dot of a row register 1 at a receiving processing section 20, a data is stored in the second row of dot of a row register 2. A data is read out from the row register 1 and an address of a receiving memory 30 is designated for each color before a data is stored. A combination determining section 41 at a data converting section 40 determines a combination of ink for a dot to be printed. If a dot where at least two colors of ink are superposed is detected from the determination results, a decision is made whether a nonrecording dot is present in adjacent to a detected dot in the main scanning direction. It it is present, an ink color having high visual sensitivity is shifted to the nonrecording dot position before printing is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image recording apparatus for recording a color image by forming pixels by overlapping a plurality of primary color inks (yellow, magenta red, cyan blue, and black).

[0002]

2. Description of the Related Art For example, an ink jet printer is known as a device for forming a color image by forming pixels by dots corresponding to a plurality of primary color inks. As a method of forming a color image, three primary colors of yellow, magenta red, and cyan blue (hereinafter, denoted by Y, M, and C, respectively, which are complementary to the three primary colors of red, green, and blue light). And a method of superimposing primary color inks at the same position (subtractive color mixing). As a method for expressing black in the color image forming method, these 3
There are a method of expressing black (hereinafter denoted by a BK symbol) by overlapping colors, and a method of forming a BK by using BK as a fourth primary color. In the color image, BK forms BK and is mainly used for undercolor removal. This is a method of replacing a gray component of a color represented by a mixture of three primary colors with black ink.

[0003]

However, in the conventional color image recording apparatus, if a plurality of primary color inks are deposited on the same pixel on the recording surface and mixed, the following inconveniences will occur. In the pixel of the mixed color by the above-mentioned mixing, if the second color is superimposed in the non-dry state of the first color, the second color flows out without being fixed. Generally, the lightness of ink is in the order of Y >>M>C> BK, and a recording material such as paper often exhibits a white color with high lightness. When recording is performed on such a recording material, recording is performed. The visual sensitivity of Y, which has the smallest lightness difference from the material, is low, and conversely, M, C, B with low lightness
Since K has a large difference in brightness from the recording material, the visual sensitivity increases. Therefore, when the second color is ink with high visual sensitivity, the dots of the first color and the second color appear to be shifted.

The present invention solves the above-mentioned problems of the conventional color image recording apparatus, and is intended to be applied to a case where high-visibility ink overlaps low-visibility ink in a non-dried state depending on the printing direction and nozzle arrangement. An object of the present invention is to provide a color image recording apparatus in which dot displacement does not occur and image quality does not deteriorate.

[0005]

In a color image recording method of forming a color image by superimposing a plurality of primary color inks and recording the same on a recording medium, print data transmitted from a host device is divided for each ink color. Storing, reading out the stored data for each ink color, determining a combination of ink colors to be printed at the same position, detecting a dot where two or more inks overlap based on the determination result, It is determined whether the dot adjacent to the target dot is a non-recording dot based on the result of the determination. If the adjacent dot is a non-recording dot, the target dot is determined. A color image is recorded by moving at least one of the ink colors to be formed to the non-recording dots.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a control block diagram of an ink jet printer according to the present invention. In FIG. 1, reference numeral 1 denotes a host device such as a host computer or a word processor, and reference numeral 2 denotes an inkjet printer connected to the host device. The inkjet printer 2 has the following configuration. Reference numeral 10 denotes a main control unit that controls the entire printer, and includes a microprocessor, a program memory for operating the microprocessor, and a random access memory connected to the microprocessor. Reference numeral 20 denotes a reception processing unit which performs a process of receiving data transmitted from a higher-level device and dividing the data into data for each color. Reference numeral 30 denotes a reception memory, in which a storage area is divided for each color in order to store each color divided by the reception processing unit 20. Numeral 40 denotes a data conversion unit, which reads data for each color stored in the reception memory 30, determines the overlap of each color, determines the presence or absence of data of peripheral dots for dots where at least two or more colors of ink overlap,
A process of distributing overlapping colors to surrounding dots is performed. 50
Is an image memory, which is a memory for storing data converted by the data conversion unit 40. A drive circuit control unit 60 is connected to a print head 61, a space motor 62 (hereinafter, referred to as an SP motor 62), and a line feed motor 63 (hereinafter, referred to as an LF motor 63), and performs control based on a printing operation. 80 is a paper end sensor,
A cover open sensor, an ink empty sensor, and the like are connected to the main control unit 10. An operation panel 90 transmits a switch state to the main control unit 10 and displays a signal from the main control unit 10 on a lamp, an LCD, or the like.

FIG. 2 is a nozzle arrangement diagram of the ink jet printer according to the present invention. The nozzle arrangement diagram in this case shows a state where the inkjet head is viewed from the paper surface side. In FIG. 2, reference numeral 61A denotes a BK nozzle;
B indicates a Y nozzle, 61C indicates a M nozzle, and 61D indicates a C nozzle. 61
The nozzles A to 61D have m nozzles n1 to nm, respectively.
Consists of The intervals L between the nozzles are set at equal intervals. In the case of forward printing (the direction A in FIG. 2), printing is performed from the BK nozzle, and printing of Y is started after the nozzle has moved the distance L. In the printing of M and C, the nozzle is further moved to the distance L,
Started after moving 2L. Reverse printing (Fig. 2
In the case of (B direction), printing is started from the nozzle C, and then printing is started in the order of M, Y, and BK. Since the print data transmitted from the host device is sent in one direction regardless of the actual print direction, the drive circuit control unit 60 sends the print data in the print direction to the print head 61 and prints it. The interval between the nozzles can be arbitrarily set depending on the nozzles. However, in the present invention, the description will be made on the assumption that the interval between the nozzles is the same. Further, in the present invention, an example is shown in which the nozzles are arranged in a row, but it is also possible to control each nozzle separately in an odd-numbered nozzle group and an even-numbered nozzle group.

Next, details of the embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 3 is a detailed control block diagram of the ink jet printer according to the embodiment of the present invention.
FIG. 4 is a detailed explanatory diagram of the reception control. FIG. 5 is a detailed explanatory diagram of the combination determination processing unit.

In FIG. 3, a reception processing unit 20 separates print data received from a higher-level device for each color, and
0 is stored corresponding to each color storage area. Reception processing unit 2
Numeral 0 is provided with column registers 1 and 2 for processing data sent from the host device in units of one dot column, and the column registers 1 and 2 store data from the host device and a reception memory 3.
Control is performed so that a toggle operation is performed between reading and writing data to 0. When the data of the first dot column is stored in the column register 1, the reception processing unit 20 stores the data of the second dot column received from the host device in the column register 2 and reads the data stored in the column register 1. The data of each color is stored in the reception memory 30 by specifying the address of the reception memory 30 for each color. The address of the reception memory 30 is sequentially updated with the start address designated for each color and the number of bytes received. When the data of one dot string is stored in the reception memory 30, the reception processing unit 20
Notifies the main control unit 10 and the data conversion unit 40 that the data processing of one dot row has been completed. Data converter 4
0 is a combination determining unit 41 that determines the combination of inks of the dots to be printed, a combination data storage unit 42 that stores the determination result of the combination determining unit 41, and at least two colors based on the determination result of the combination determining unit 41. An edit processing unit 43 that detects a dot on which ink overlaps and determines whether there is a non-recording dot in a dot adjacent to the detected dot in the main scanning direction (row direction),
When there is a non-recording dot, the combination data is changed so that the ink color with high visual sensitivity is moved to the non-recording dot position, and when the processing of one dot row by the editing processing unit 43 is completed, the combination data storage unit 42 A development data creation unit 44 that reads the combination data of one dot row, performs a development process, and writes the developed data in the image memory 50;

FIG. 4 shows details of the reception data and the reception memory 30. BK * n bytes + Y * n bytes + M * n bytes + C * n
Byte (n bytes represent the number of data in one dot row for each color)
Is sequentially sent from the host device. FIG.
(A) is n-byte data for each color stored in the column register 1. The reception processing unit 20 stores B in the column register 1
The K data is read out, and one byte is designated by specifying the start address 0000H, which is the BK storage area of the reception memory 30. Here, H at the end of the address represents hexadecimal hexadecimal. After storing 1 byte, add the address +
Then, the second byte is stored, and the storage is continued up to n bytes.
After storing n bytes, read the next Y data,
Start address 2 which is the Y storage area of the reception memory 30
000H is specified and 1-byte data is stored. Similarly, data of M and C is stored, and data of one dot row is stored in the reception memory 30.

Next, the detailed operation of the combination determining section 41 will be described with reference to FIG. Upon receiving the notification that the storage of the one-dot-string data has been completed from the reception processing unit 20, the combination determination unit 41 reads out the Y, M, C, and BK data from the memory area for each color in the reception memory 30, and determines the combination. Stored in registers 1-4. FIG. 5A shows a state where data is stored in the combination determination registers 1 to 4. Each bit “1” indicates that data is present, and “0” indicates that no data is present. When writing the data to the combination determination registers 1 to 4, the combination determination unit 41 sequentially checks the combination of the ink colors for each bit from bit 0 to bit n of each register. Bit 0 in FIG.
Are BK = 0, C = 1, M = 1, Y = 1, and it can be seen that the C, M, and Y inks overlap. Then, the combination data is determined based on the data conversion table shown in Table 1 in order to output the combination data.

[0013]

[Table 1]

The combination data in the above case is 10
00B. Here, B at the end of the address represents a binary number. The combination data is sent to the combination data storage unit 42 and stored in the combination data register 1 as shown in FIG. The data of the combination data conversion table is stored in the data conversion unit 40 in advance.
A non-volatile ROM may be provided therein and stored, or the data may be downloaded to a register in the data conversion unit 40 when the printer is started. In this embodiment, the data of the combination data conversion table is downloaded to the combination data conversion register 45 in the data conversion unit 40 and used. Bit 0
When the storage of the combination data is completed, the same processing is repeated up to bit 1 to bit n. Bits 0 to 0 of the data stored in the combination determination registers 1 to 4
When the combination of all the bits up to the bit n has been checked, the next one dot string data is read from the reception memory 30, the combination determination registers 1 to 4 are rewritten, and the same processing is performed. Since the ink to be combined has a maximum of four colors, it is necessary to examine the combination of data for four dot rows in the moving direction (main scanning direction) of the print head 61 in order to examine the dots to be replaced (adjacent non-recording dots). Yes. Therefore, the combination data register has a register for storing combination data for at least a 4-dot string.

Next, the operation of the edit processing unit 43 will be described in detail with reference to the comparison processing flowchart of FIG. When the combination judging section 41 finishes checking the combination of the ink colors, the editing processing section 43 sets the combination data registers 1 to 4
, And replace the mixed color dot. s1
Sets the number of bits n of one dot row to a variable x. In s2, the initial value 0 is set to a variable y representing the number of empty dots.
Is set. At s3, it is determined from bit n data (Dn1) of the combination data register 1 whether bit n is a mixed color of two or more colors. Dn1> 0100
In the case of B, it is determined that two or more colors are mixed, and the process proceeds to s4. D
When n1 <= 0100B, it is determined that the color mixture is not a mixture of two or more colors, and the process proceeds to s11 without data conversion. At s4, bit n data (Dn2) of combination data register 2
It is determined whether or not the bit n is an empty dot (Dn2 = 0000B). If it is not a blank dot, the process proceeds to s10. In the case of an empty dot, the process proceeds to s5. At s5, the value of the number y of empty dots is updated. (Y = y + 1) In s6, bit n is an empty dot (Dn3 = 00) from bit n data (Dn3) of the combination data register 3.
00B). If it is not a blank dot, the process proceeds to s10. If it is an empty dot, the process proceeds to s7. At s7, the value of the number y of empty dots is updated. (Y = y + 1) In s8, bit n is an empty dot (Dn4 = 00) from bit n data (Dn4) of combination data register 4.
00B). If it is not a blank dot, the process proceeds to s10. If it is a blank dot, the process proceeds to s9. At s9, the value of the number y of empty dots is updated. (Y = y + 1) At s10, data conversion is performed using bit n data (Dn1) of the combination data register 1 and the number of free dots y. However, if the number of free dots y is zero, data conversion is not performed, and if the number of free dots y is 1 or more, conversion is performed based on the number of free dots y and Dn1. In s11, the number of bits 1 for which processing has been completed is subtracted from the number of bits x of one dot string. (X = x−1) In s12, it is determined whether or not the variable x representing the number of bits is zero, and it is determined whether or not the comparison process has been completed for all the bits of the one dot row. If the variable x is not zero, the process proceeds to s2 to process the next data. If the variable x is zero, the process proceeds to s13 because the comparison process for one dot row has been completed. At s13, the data of the combination data register 2 is stored in the combination data register 1, the data of the combination data register 3 is stored in the combination data register 2,
The data of the combination data register 4 is shifted to the combination data register 3 respectively. Thereafter, the combination determination unit 41 is notified that the determination of the combination of the next dot row is to be performed, and the comparison process ends.

Next, data conversion performed when the number of empty dots is 1 or more in s10 of FIG. 6 will be described in detail with reference to FIG. FIG. 7 shows an example of data conversion when the present invention is implemented. In FIG. 7, data indicating dot recording constituting one pixel to be recorded is schematically shown on the left side, and data to be actually recorded is shown on the right side. Each dot to be recorded is indicated by a circle, and the ink color is indicated by an English character in the dot. In the drawing, an area without a mark indicates a state without a recording dot.

FIG. 7 shows a case where the bit n data of the combination data register is a mixture of two colors and the number of empty dots y is 1 or more.
This will be described with reference to FIG.

FIG. 7A shows a case where red is represented by a mixture of two colors of M and Y. As shown on the left side of FIG. 7A, when there is a mixed color dot of M and Y to represent red, it is assumed that M is the first color and Y is the second color in order from the ink color having the highest visual sensitivity characteristic. Then, the first color is moved to a dot adjacent to the mixed color dot, and the second color is placed at the original mixed color dot position.

FIG. 7B shows a case where the bit n data of the combination data register expresses gray by a mixture of three colors of C, M and Y, and the number of empty dots y is 1 or more.

FIG. 7 (b1) shows a case where the number y of empty dots is one. As shown on the left side of FIG. 7 (b1), when there is a mixed color dot of C, M and Y in order to express gray, C is the first color and M is the second color in order from the ink color having the highest visual sensitivity characteristic.
If the color and Y are the third color, the first color is moved to a dot adjacent to the mixed color dot, and the second color and the third color are set at the original mixed color dot position.

FIG. 2B shows the case where the number y of empty dots is two. As shown on the left side of FIG. 7B2, when there is a mixed color dot of C, M, and Y to express gray, C is the first color and M is the second color in order from the ink color with the highest visual sensitivity characteristic.
Assuming that the color and Y are the third color, the second color is moved to the dot adjacent to the mixed color dot, the first color is moved to the dot adjacent to the dot moved by the second color, and Put the third color.

FIG. 7C shows a case where the bit n data of the combination data register is a mixed color of three colors of C, M, and Y and a color mixture of four colors including BK for removing undercolor and the number of free dots y is 1 or more. Is represented.

FIG. 7 (c1) shows a case where the number y of empty dots is one. As shown on the left side of FIG. 7 (c1), when there are mixed color dots of BK, C, M, and Y, BK is the first color, C is the second color, and M is the 3
Assuming that the color and Y are the fourth color, the first color is moved to a dot adjacent to the mixed color dot, and the second color, the third color, and the fourth color are placed at the original mixed color dot position.

FIG. 7 (c2) shows a case where the number y of empty dots is two. As shown on the left side of FIG.
And Y are mixed color dots, BK is the first color, C is the second color, M is the third color, and
If Y is the fourth color, the second color is moved to a dot adjacent to the mixed color dot, the first color is moved to a dot adjacent to the dot moved by the second color, and the third color is moved to the original mixed color dot position.
Put the color and the fourth color.

FIG. 7C3 shows a case where the number y of empty dots is three. As shown on the left side of FIG. 7C3, when there is a mixed color dot of BK, C, M, and Y, BK is the first color, C is the second color, and M is the 3
Assuming that the color and Y are the fourth color, the third color is moved to the dot adjacent to the mixed color dot, the second color is moved to the dot adjacent to the dot moved by the third color, and the second color is moved. The first color is moved to a dot adjacent to the selected dot, and the fourth color is placed at the original mixed color dot position.

By arranging inks with poor transmittance in the main scanning direction and expressing them in an additive color mixture as described above, dot displacement and a difference in color tone due to the ink overlapping order are eliminated.
The print quality can be prevented from deteriorating. In addition to a head in which the nozzles of each color ink are arranged in the paper feed direction (sub-scanning direction) such that the order of color mixture is determined by the nozzle arrangement, the nozzles of each color ink are arranged at regular intervals in the main scanning direction. This is also effective when the printing direction is set to both directions with the head. Also, the movement of the mixed color dots increases the apparent number of dots and hides the ground color of the paper, so that there is an effect that the resolution does not decrease when printing low-resolution data.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention. In an embodiment of the present invention, at least two
Detecting dots where inks of the same color or more overlap, and preferentially moving ink dots with high visual sensitivity characteristics to vacant dots. The above conversion may be performed only for the mixed color dots including the color. In the above embodiment, the number of ink colors to be moved is variable depending on the number of empty dots. However, the upper limit of the number of conversions may be determined in advance, and conversion may be performed only for that number. Further, although the moving direction of the dots is the main scanning direction, it may be the sub-scanning direction.

[0028]

As described above, according to the present invention,
In a color image recording apparatus, in particular, a color image recording apparatus in which pixels are formed by dots corresponding to a plurality of primary color inks and a color image is recorded, adjacent dots are non-recording for dots where at least two or more colors of ink overlap. At this time, an ink color with high visual sensitivity is recorded at an adjacent dot position. In this case, pixels having the same color can be formed irrespective of the drying state of the previously recorded ink, and there is no difference in color due to the order of ink overlay.

[Brief description of the drawings]

FIG. 1 is a control block diagram of an ink jet printer according to an embodiment of the present invention.

FIG. 2 is a nozzle arrangement diagram of the inkjet printer according to the present invention.

FIG. 3 is a detailed control block diagram of the ink jet printer according to the embodiment of the present invention.

FIG. 4 is a detailed explanatory diagram of reception control in the embodiment of the present invention.

FIG. 5 is a detailed explanatory diagram of a combination determination processing unit according to the embodiment of the present invention.

FIG. 6 is a flowchart illustrating a comparison process according to an embodiment of the present invention.

FIG. 7 shows an example of data conversion in the embodiment of the present invention.

[Explanation of symbols]

 2 Printer 20 Reception processing unit 30 Reception memory 40 Data conversion unit 41 Combination determination unit 42 Combination data storage unit 43 Editing processing unit 44 Expansion data creation unit

Claims (2)

[Claims] 1. A color image recording method for forming a color image by superimposing a plurality of primary color inks and recording the same on a recording medium, wherein print data transmitted from a host device is stored separately for each ink color, Read the stored data for each ink color,
A combination of ink colors to be printed at the same position is determined, a dot where two or more colors of ink overlap is detected based on the determination result, the detected dot is set as a target dot, and the target dot is determined based on the determination result. It is determined whether or not a dot adjacent to the dot is a non-recording dot. If the adjacent dot is a non-recording dot, a predetermined color among the ink colors printed on the target dot is adjacent to the target dot. A color image recording method characterized by recording a color image by moving to a dot. 2. A color image recording apparatus for forming a color image by superimposing a plurality of primary color inks and recording the same on a recording medium, wherein print data transmitted from a host device is divided into data for each ink color and output. A reception control unit, a first storage unit that receives data for each ink color output by the reception control unit and stores the data for each ink color, and a first storage unit for each ink color stored in the first storage unit. A combination determining unit that reads data and determines a combination of ink colors to be printed at the same position; a second storage unit that stores data indicating the combination of ink colors determined by the combination determining unit; The data indicating the combination of the ink colors is read from the second storage unit for the predetermined dot determined by the unit, and at least two or more colors of ink are read. In the case of a dot, the data indicating the combination of ink colors is read from the second storage unit for the dot adjacent to the dot, and it is determined whether or not the dot adjacent to the dot is a non-recording dot. In the case of, an editing processing unit that rewrites data indicating a combination of the ink colors forming the dots and the dots adjacent to the dots, and a third storing data indicating the combination of the ink colors processed by the editing processing unit A color image recording apparatus, comprising: a storage unit; and a development data creation unit that reads data indicating a combination of ink colors stored in the third storage unit and develops the data into data for each ink color.