JPH0419030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording method in which a recording head having a plurality of recording element arrays is moved back and forth in a direction perpendicular to the recording element arrays to perform dot recording.

Various types of recording apparatuses that perform dot matrix recording using this type of multi-recording head include inkjet printers, wire dot printers, and thermal head printers, among which the inkjet printer is a typical recording apparatus. The printer is generally configured as shown in FIG. That is, in the figure, for example, the first to fourth multi-nozzle heads 2-1 to 2-4 are arranged on the carriage 1 in order from the left, and are arranged in the order of cyan (C), magenta (M), and yellow (Y). and black (K), and a flexible pipe 3 is connected to each multi-nozzle head.
A flexible insulating belt 5-1 in which each color of ink is supplied from the ink tank 4 through the ink tank 4, respectively, and in which a large number of conductive wires are arranged and embedded respectively.
~5-4, relay terminal board 6 and integrated power supply belt 7
drive signals are respectively supplied through the respective terminals. The carriage 1 having such a configuration is placed on two guide rails 8 and an endless belt 9 connected thereto is driven by a pulse motor 10 to cause the carriage 1 to reciprocate in the X direction in the figure, thereby performing main scanning. A pulse motor 15 connects the stretched recording paper 12 to a pair of rollers 14 via pairs 13 and 14.
, the multi-nozzle heads 2-1 to 2 are fed on the recording paper 12 to perform sub-scanning in the Y direction in the figure.
A color image is recorded using each color ink jetted from -4. In addition, stoppers 11-1 and 11-2 are arranged at both ends of the reciprocating path of the carriage 1 to determine the main scanning range.

The state of color image recording by the inkjet printer configured as described above is illustrated in FIG. 2. That is, when recording a color image as a CP by repeatedly feeding the recording paper 12 stepwise in the direction of the arrow in the figure and performing sequential head scans as main scans in the left and right directions,
In head scanning 1 performed rightward in the figure, black multi-nozzle heads 2-4 are arranged in order from the left.
The order in which the same dots are repeatedly recorded by the multi-nozzle heads 2-1 to 2-3 other than the above is as shown in FIG. 3A.
In head scanning 2, in which magenta (M) and cyan (C) are sequentially performed in the left direction in the figure, multi-nozzle heads 2-1 are similarly arranged in order from the left.
The order in which the same dots are repeatedly recorded in steps 2-3 is cyan (C), magenta (M), and yellow (Y) on the recording paper 12, as shown in FIG. 3B. The order of duplicate recording on the outbound and return trips is reversed.

In such a device, all the dots to be recorded are struck during either the forward or backward movement, so that adjacent dots are struck before the ink is completely absorbed. Therefore, if ink droplets that have landed adjacent to each other become integrated, ink absorption may be delayed or ink may sag, which may adversely affect printing quality. This adverse effect is particularly noticeable when adjacent inks are of different colors. Furthermore, when ink of different tones is sequentially and overlappingly deposited on the recording paper 12, the recording paper 1
Since the ink deposited directly on the recording paper 12 is well absorbed by the recording paper 12, the size of the recording dot is the same as the thickness of the ink thread that struck the recording paper 12, whereas the size of the recording dot is the same as the thickness of the ink thread deposited on the next stage. The ejected ink is not absorbed well and spreads out, so the size of the recorded dot becomes larger than the ejected ink of the first stage.If the order of the color tones of the ink that is repeatedly recorded in the same way is different, the size of each color ink dot will be different. In addition to the different states, the state of absorption and reflection of the incident white light by each of the overlappingly recorded color inks also differs depending on the order of the overlapping recording of each color ink. Therefore, the color tone obtained by subtractive color mixing of the three complementary colors, cyan (C), magenta (M), and yellow (Y), differs due to the difference in the order of overlapping recording of each complementary color ink. Even if subtractive color mixing of three complementary colors is performed at the same mixing ratio in the above-mentioned head scans 1 and 2, that is, in the forward and backward passes of the main scan, there will be a difference in the recorded color tone that is actually obtained, and the reciprocating scan of the multi-nozzle head A major drawback of this type of conventional recording method is that horizontal stripes are generated in the recorded color image due to color tone deviation, which significantly impairs the image quality.

The present invention has been made in view of the above points, and its purpose is to prevent deterioration in image quality when performing dot recording by moving a recording head back and forth in a direction perpendicular to the recording element array, and to achieve high quality. An object of the present invention is to provide a recording method that allows image recording of images.

That is, the present invention arranges a plurality of recording element rows,
When performing main scanning for dot matrix recording by reciprocating in a direction perpendicular to the recording element array, the number of dots to be recorded is smaller than the total number of dots to be recorded in at least one of each row and each column of the recording dot matrix in the forward pass of the main scanning. The present invention provides a recording method for intermittently recording the remaining dots in at least one of the rows and columns during the return pass of the main scan.

Dot matrix recording is performed by reciprocating a recording means in which a plurality of recording element arrays arranged in parallel for recording dot arrays using coloring materials of mutually different colors in a direction in which the plurality of recording element arrays are arranged relative to the recording material. When performing main scanning, intermittently records fewer dots than the total number of dots to be recorded in at least one of each row and each column of the recording dot matrix for each color in the forward pass of the main scan, and Among the dots to be printed, the dots in which coloring materials of different colors overlap are printed in a predetermined order according to the arrangement order of the plurality of recording element rows, and in the return pass of the main scanning. The remaining dots for each color are intermittently recorded, and the remaining dots recorded in the forward pass, on which coloring materials of different colors are overlapped, are colored in different colors in an order different from the predetermined order. The present invention provides a recording method characterized by recording materials in duplicate.

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

First, based on the above-mentioned difference in the order of overlapping recording in the forward and backward passes of the main scan due to the reciprocating movement of the multi-recording head, it is possible to reduce the occurrence of horizontal stripes due to color tone deviation that occur in recorded color images when using the conventional recording method. An example of the embodiment is shown in FIG. That is, assuming that each recording dot of head scan 1, indicated by a white circle in the figure, is recorded redundantly in the order of yellow (Y), magenta (M), and cyan (C), on the other hand, the dots indicated by a black circle in the figure Each recording dot in head scan 2 is, for example, the result of overlapping recording in the order of cyan (C), magenta (M), and yellow (Y), and the order of duplication of each color in the overlapping recording changes alternately for each successive head scan. Because of the inversion, horizontal stripes due to color tone deviation appear as shown in the figure, with a width corresponding to the length of the recording element row of the multi-recording head, and the quality of the recorded color image is significantly impaired.

On the other hand, in the recording method of the present invention, for example, as shown in FIG. 5, each successive head scan, which was conventionally performed alternately in only one direction as described above, is performed by reciprocating scanning, respectively. Main scanning is performed in both the forward and backward passes intermittently so that the outgoing print dot arrays indicated by white circles in the figure and the return dot arrays indicated by black circles in the figure are mixed alternately. As a result, the color tone deviation of the overlapping recorded dots caused by the difference in the scanning direction is finely dispersed in the recorded image and becomes less noticeable, and image quality deterioration due to such color tone deviation can be prevented. Regarding multi-recording heads, which are usually on-demand type, the ink ejection response speed to the head is lower than the moving speed of the head, so even if a reciprocating scan is performed for each successive head scan, the overall recording speed will be lower than the head movement speed. As such, there is no significant difference from conventional head scanning which is performed alternately in only one direction.

FIG. 6 shows an example of a schematic configuration of a recording control circuit according to the method of the present invention that performs intermittent recording as described above. In the illustrated configuration, for example, processing such as complementary color conversion and masking is performed on each digital primary color signal converted from a three primary color image signal obtained from an image reading device such as a color television camera, and a pattern generator is generated from the density signal of each color. 4× formed by
Three complementary color recording signals (Y), (M), and (C) for each pixel formed by a 4-dot matrix are stored in the page memory 22 for each color of the recorded image, and the control device 2
Accessed by address signal ADR from 1,
Similarly, the control device 21 controls each complementary color (Y), (M), and (C) in 16-bit word units, which are made up of 4 bits for one row of each pixel signal consisting of a 4×4 dot matrix. Each complementary color (Y), (M), (C) is read out sequentially in response to the application of the read signal READ from
The signals are supplied to each buffer memory 23 respectively, and latched to the respective built-in latch circuits by the latch signal LATCH from the control device 21, and then,
Similarly, it is driven by the shift signal SHIFT from the control device 21 and is sequentially supplied to the built-in shift register, and each complementary color image signal (Y), (M), (C) of 128 bits for 8 words is sent to the shift register. At the time of storage, each complementary color image signal of each 128 bits is sent to the recording command signal from the control device 21.
By PRINT, the data is sequentially read out all at once on the multi-recording head at an appropriate timing according to the spacing of each recording element row, and then the data is read out all at once on the multi-recording head via the head driver 24 for each complementary color (Y), (M), and (C). Each complementary color (Y), (M), and (C) is supplied to a multi-recording head 25 in which 128 recording elements are arranged in a row, and each complementary color (Y) is sequentially printed onto a recording sheet (not shown). ), (M), and (C).

As described above, each complementary color image signal (Y),
(M) and (C) are supplied to the multi-recording head 25, and at the same time, each counter provided in the control device 21 counts and generates a head step forward signal PX and a head movement direction instruction signal DIRT, respectively, to the pulse motor driver 26. The recording paper advance signal PY is supplied to the head feeding pulse motor 27 via the pulse motor driver 28 to move the multi-recording head 25 in the required direction by the required amount. The recording paper (not shown) is fed by the recording width of the multi-recording head 25. The head step signal PX steps the head by one dot pitch, that is, one white circle or one black circle in the recorded image, with one pulse.

Next, the processing steps of the recording method of the present invention when an image with the dot configuration shown in FIG. The following will be explained.

FIG. 7A shows a flowchart of the entire process of recording an image in the manner shown in FIG. After confirming that the number of paper feeds has been reset to the starting edge of one page of image recording where the number of paper feeds is 0, step S2 is performed.
Then, in the process of the one-way scan CALL "SCAN" in either the left or right direction, which will be described later with reference to FIG. to be done. Next, in step S3, the head step signal from the control device 21 in the configuration shown in FIG.
After moving the multi-recording head by one pitch from the position of the white circle in forward scanning to the position of the black circle in backward scanning using PX, the process proceeds to step S4, and the scanning direction is determined by the head movement direction instruction signal DIRT from the control device 21. Reverse and move to backward scanning, then one-way scanning CALL “SCAN” in step S5
The subroutine sequentially records black dots in the leftward return path of head scan 1. Next, in step S6, the number of reciprocating scans NSCAN is incremented, and then the process moves to step S7, where 1
16 round trip scans required to record images for a page
Determine whether NSCAN has been performed or not. At this moment, head scan 1 has just been completed, and NSCAN =
Since the state is 1, the process moves to step S8.
In step S8, the recording paper advance signal PY from the control device 21 is used to feed the paper by the length of the recording element row of the head in order to shift from head scan 1 to head scan 2, and then to step S9. Head movement direction instruction signal DIRT from the control device 21
After reversing the scanning direction and moving to the forward scan of head scan 2, and then performing the same reciprocating scan as in the process from step S2 to step S7 described above in the process from step S10 to step S15, Since the number of reciprocating scans NSCAN has not reached 16, the process proceeds to steps S16 and S17 in sequence, and after performing paper feeding and reversal of the scanning direction in the same manner as in steps S8 and S9,
Returning to step S2, a reciprocating scan of head scan 3 is performed, and the same head scan is repeated thereafter to perform a reciprocating scan.
When the number of NSCANs reaches 16, it means that one page's worth of image recording has been completed.

Next, the above-mentioned one-way scanning CALL "SCAN" subroutine consists of the flowchart shown in FIG.
After confirming in step S21 that the count value is 0 and that the multi-recording head has been reset at the start of the reciprocating scan, in step S22, data is transferred from the page memory 22 to the buffer memory 23 in the configuration shown in FIG. , according to the subroutine described later in FIG. 7C of the data pack transfer CALL "DPACK" in which each complementary color image signal (Y), (M), (C) of 8 words worth 128 bits is made into one pack, the image for recording is Transfer the signal, then step S
At 23, a recording command signal is sent from the control device 21.
Depending on the application of PRINT, each complementary color (Y), (M), (C)
One pack of 128-bit image signals is read out from the buffer memory 23 at the same time and sent to the head driver 2.
4 to the recording element rows for each complementary color (Y), (M), and (C), and dot recording of one row of white circles or black circles in the recorded image shown in FIG. 5 is performed. Then,
In step S24, 2 is added to the count value of the counter CNTR1 in the control device 21 that forms the head step signal PX, and a new count when stepping every other column is calculated as shown in FIG. The numerical value is obtained, and then, in step S25, the new step signal is
It is determined whether the count value of PX has reached the total count value Pall of the one-way scan given in advance, that is, whether the one-way scan is completed or not. If it is completed, the one-way scan subroutine is completed. from step 26 to the next step in the main routine and, if not completed, to step 26.
and 27, followed by two head step signals.
Send PX to step every other row, and then
Returning to step S22, the above-described process is repeated until the one-way scan is completed.

Next, data pack transfer is performed in step S22 in the one-way scan CALL subroutine described above.
The subroutine of CALL “DPACK” is shown in Figure 7C.
It consists of the flowchart shown in Figure 8, and as described later in Figure 8, the image for one page is 512×
One of the recording element arrays is composed of a 512 pixel matrix, where one word is 16 bits for 4 pixels in a 4 x 4 dot matrix, and 128 bits for 8 words are 1 pack.
The recorded data packs DPACK for each batch are sequentially transferred from the page memory 22 to the buffer memory 23 in the configuration shown in FIG. Send. That is, in step 31, after confirming that the count value of the counter CNTR2 that counts the latch signal LATCH that latches the image data from the page memory 22 word by word into the buffer memory 23 in the control device 21 is reset, In step S32, the address signal ADR from the control device 21 is sent to designate the data address of the page memory 22, and then in step S33, the read signal READ is supplied from the control device 21 to read 1 word of 16 bits. Then, in step S34, the latch signal LATCH is supplied from the control device 21 to the buffer memory 23 to latch the image data of 1 word and 16 bits. Next, in step S35, after confirming that the count value of the counter CNTR3 in the control device 21 that counts the next 1 word 16-bit address has been reset to 0,
Proceeding to step S36, the control device 21 sends out the shift signal SHIFT, and the buffer memory 23
The image data within is sequentially shifted by 16 bits,
Then, in step S37, the address counter
The next bit address is obtained by adding 1 to the count value of CNTR3, and then, in step S38, it is determined whether the count value of bit address counter CNTR3 only counts 16 bits of one word, and this process is repeated 16 times. This process is repeated until the next 1 word of 16 bits has been addressed. Then,
In step S39, 1 is added to the count value of the latch counter CNTR2 to increment the number of latches in units of words in the buffer memory 23, and then in step S40, the latch is added to latch the image data of 1 word and 16 bits in the buffer memory 23. signal
It is determined whether the count value of the counter CNTR2 in the control device 21 that counts the number of LATCH transmissions has reached the number of latches of 8 for 1 pack of 8 words, and the above procedure is continued until the count value reaches the number of latches of 8. Repeat the process.

Next, FIG. 8 shows an example of how image data is stored for each complementary color (Y), (M), and (C) in the page memory 22 in the configuration shown in FIG. In other words, one page's worth of image data is expressed by representing each pixel in a 4x4 dot matrix, assigning a bit address to each dot, and arranging the data in rows and columns of 512 pixels both vertically and horizontally.
The upper left end of this pixel matrix is set as bit address 0, and bit addresses are sequentially assigned to the right. One word is 4 pixels of 4 bits per row in a 4x4 dot matrix of each pixel, and 8 words of 16 bits per word are equivalent to the width of the head that is simultaneously recorded by the recording element array in the multi-recording head. Pack, 1 pack 32 pixels 128
Let bits be a data pack of image data. Therefore, one page's worth of image data is
512 pixels, 128 words, 2048 bits. One page of image data configured in the bit matrix is scanned back and forth every other line in the vertical direction from the upper right corner in units of one data pack, and sequential head scanning is performed in accordance with the image recording mode shown in FIG. I do. By vertical/horizontal conversion that requires head scanning, the hassle of bit access can be avoided and word access can be performed efficiently. For example, in the forward pass of head scan 1, word addresses 120 to 127 are used as shown in the figure.
Starting from one pack of 8 words of image data, word access is performed every other line, and the paper is sequentially fed by the width of the head in a stepwise manner, thereby performing image recording in the manner shown in FIG.

Therefore, the manner of word address access in the reciprocating scan of the multi-recording head is, for example, as follows. Head scan 1 (outward) (1) 120-127 (2) 376-383 (3) 632-639 〓 〓 (1024) 262008-262015 Head scan 1 (return) (1) 262136-262143 (2) 261880-261887 〓 〓 (1023) 504-511 (1024) 248-255 Head scan 2 (outward) (1) 240-247 (2) 496-503 〓 〓 Occurs during the reciprocating scan of the multi-recording head performed as explained above. As shown in Fig. 5, intermittent recording for dispersing color tone deviations of overlapping recording dots involves not only relatively simple intermittent scanning of every other row, but also
This can be done with various modifications, for example, as shown in FIG. As shown in the figure, it is also possible to make the overlapping recording dots appear alternately in every other row in the column direction, that is, in the direction perpendicular to the head scanning direction, in the forward and backward passes of the head scan.

As is clear from the above explanation, in a printing apparatus that records dot matrix images, such as an inkjet printer, for example, the color tone deviation between overlapping printed dots that occurs during the forward and backward scanning passes of the multi-print head can be corrected. By densely mixing these two types of overlapping recorded dots, it is possible to prevent image quality deterioration due to horizontal stripes, etc., which conventionally occurs in recorded images based on such color tone deviations, by making the color tone deviations less noticeable. , can obtain high quality recorded color images.

As described above, according to the present invention, the number of dots smaller than the total number of dots to be recorded in each row and at least one of each row of the recording dot matrix is intermittently recorded in the forward path of the main scan, and the number of dots smaller than the total number of dots to be recorded in at least one of each row of the recording dot matrix is intermittently recorded. Since the remaining dots in at least one of the rows and columns are intermittently recorded in the dots, it is possible to prevent various problems that may occur between adjacent dots, prevent deterioration of image quality, and record high-quality images. become.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an inkjet printer, FIG. 2 is a line diagram schematically showing the mode of screen scanning of the multi-recording head, and FIGS. 3A and 3B are the outgoing path of the head scanning. FIG. 4 is a side view comparing and showing the difference in the structure of overlapping recording dots between the two directions, FIG. 4 is a diagram showing the manner in which color tone shift occurs in the recorded image, and FIG. A diagram showing an example of the mode of dispersion of color tone deviation in an image; FIG. 6 is a block diagram showing an example of the configuration of a recording control circuit according to the method of the present invention;
7A to 7C are flowcharts sequentially showing examples of the operation mode of the recording control circuit, FIG. 8 is a diagram showing an example of the image data storage mode in the recording control circuit, and FIG. 9 and FIG. 10 are diagrams showing other examples of the mode of dispersion of color tone deviation in images recorded by the recording method of the present invention. 1... Carriage, 2-1 to 2-4... Multi-nozzle head, 3... Flexible pipe, 4... Ink tank, 5-1 to 5-4... Flexible insulating belt, 6... Relay terminal board, 7... Comprehensive power supply belt,
8...Guide rail, 9...Endless belt, 10,
15...Pulse motor, 11-1, 11-2...
Stopper, 12... Recording paper, 13, 14... Roller pair, 21... Control device, 22... Page memory, 23... Buffer memory, 24... Head driver, 25... Multi recording head, 26, 28
...Pulse motor driver, 27, 29...Pulse motor.

Claims (1)

[Scope of Claims] 1. A recording device in which a plurality of recording element arrays arranged in parallel for recording dot arrays using coloring materials of mutually different colors is reciprocated relative to a recording material in the arrangement direction of the plurality of recording element arrays. When performing main scanning of dot matrix recording by moving, intermittently records a smaller number of dots than the total number of dots to be recorded in at least one of each row and each column of the recording dot matrix for each color in the forward path of the main scanning. At the same time, among the dots recorded in the forward pass, the dots in which coloring materials of different colors are overlapped are recorded by overlapping coloring materials of different colors in a predetermined order according to the arrangement order of the plurality of recording element arrays. , intermittently recording residual dots for each color in the backward path of the main scanning, and recording dots in which coloring materials of different colors overlap among the remaining dots recorded in the backward path in the predetermined order. A recording method characterized by recording coloring materials of different colors overlappingly in different orders. 2. The recording method according to claim 1, wherein the recording element discharges ink onto a recording material in accordance with an image signal.