JP2002264395A - Image recording device - Google Patents

Abstract

(57) [Summary] To make it difficult to recognize banding of a recorded image without lowering the recording speed. . A pixel interval at a recording resolution is D, and 1
The number of printing elements in one printing element row is N, and the number of printing element rows is M
In a matrix type print head 101 having a configuration in which the number N of print elements is larger than the number M of print element rows,
All the printing element arrays are arranged so that the relative distance in the sub-scanning direction is a multiple of D, longer than M × D, and shorter than N × M × D, and after printing by one main printing scan, printing is completed. Image recording is performed by repeatedly moving the medium N × M × D in the sub-scanning direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image recording apparatus.

[0002]

2. Description of the Related Art As an image recording apparatus of a serial recording type, there is an ink jet printer, which is widely used. This serial recording type ink jet printer scans a recording head having a large number of recording elements arranged in a sub-scanning direction in a main scanning direction to perform band-like recording on a recording medium,
The recording on the recording medium is completed by moving the recording medium in the sub-scanning direction and repeating this band-like recording. Here, let D be the pixel interval at the recording resolution,
The number of printing elements in one printing element array is N, and the number of printing elements in one printing head is M.

A conventional recording head is composed of M rows of recording elements having the same configuration in which N recording elements are arranged at intervals of M × D with respect to the pixel interval D at the printing resolution. Is a matrix type recording head having a configuration larger than the number of recording element rows M, and is arranged so that the relative distances in the sub-scanning direction of all the recording element rows in the M rows are shorter than M × D in the range of D or more. Configuration.

FIG. 11 exemplifies the arrangement of recording elements of a conventional recording head 110 when M = 4. The print head 110 has a structure in which four print element arrays 112 in which N print elements 111 are arranged at 4D intervals in the sub-scanning direction are shifted by D in the sub-scanning direction.

When printing is performed by a serial printing method using such a printing head 110, a total of L printing elements M rows having N printing elements formed by one printing scan as shown in FIG. Line (L = N ×
The boundary portion between the L-line print image S1 adjacent to the belt-shaped print image S0 of (M) and the error of the moving distance of the medium in the sub-scanning direction, the speed fluctuation during the print scan of the print head 110, and the print head 110 For various reasons, such as the characteristics of the recording element 111, a phenomenon in which a joint between the recorded images S0 and S1 is recognized, that is, so-called banding may occur.

FIG. 14 illustrates an example of a variation in the characteristics of the recording elements, which is one of the causes of banding. In a printing element array having N printing elements, especially at the both ends, the characteristics may be worse than those of the other parts. In this case, as shown in FIG. Image recording is performed with smaller dots. Such a printing element array is arranged as shown in FIG.
Is configured as shown in FIG. 15A,
FIG. 15B shows the result of recording in the sub-scanning direction at the end of the recording scan by the recording head 110. The end of the print image in one print scan is as shown in FIG. 16, and as a result, the print image at the boundary shown in the area a-S01 in FIG. 12 is as shown in FIG. In this case, image recording using small dots concentrates, and banding occurs.

In order to make banding peculiar to such a serial recording system inconspicuous, as shown in FIG. 13, the boundaries between the recording images S0 and S1 of adjacent recording scans are overlapped to form a boundary between the recording images S0. Part b-S
In FIG. 18, as shown in FIG. 18, print scanning is performed by thinning out image signals in the overlap area of the print image S0 in a staggered manner, and in the overlap area of the next print image S1, the previous print scan (printing) is performed. (Image) A method of recording pixels thinned out in S0, that is, a so-called banding process is performed. By performing the printing scan using such a method, the banding between the printed images S0 and S1 can be made somewhat inconspicuous as shown in FIG.

[0008]

In the conventional method, however, banding between recording scans can be made somewhat inconspicuous when image signal thinning processing in the overlap area is performed, but the same line is used in the overlap area. , It is necessary to perform two printing scans, and the printing speed is reduced accordingly.

An object of the present invention is to realize an image recording apparatus which can make it difficult to recognize banding of a recorded image without lowering the recording speed.

[0010]

According to the present invention, a recording head performs a recording scan in a main scanning direction on the basis of image information to perform recording in a band shape on a recording medium. After the recording scanning, the recording medium is moved in the main scanning direction. The image recording apparatus of the serial recording system which completes the image recording on the recording medium by alternately repeating the recording scanning in the main scanning direction and the movement of the recording medium in the sub-scanning direction by moving the recording medium in the sub-scanning direction perpendicular to the recording medium. At
The recording head includes a plurality of recording element rows having the same structure in which a plurality of recording elements are arranged in the sub-scanning direction. And a plurality of printing elements arranged so as to be the product of the number of printing elements and the number of printing elements. The matrix type has a configuration in which the number of printing elements in one printing element array is larger than the number of printing elements. The relative distance in the sub-scanning direction of all the printing element rows in the print head is a multiple of the interval in the sub-scanning direction of the pixels to be printed, and the relative distance in the sub-scanning direction of the adjacent printing elements in one printing element row. The distance is longer than the interval, and is shorter than the product of the number of recording elements in one recording element row and the interval in the sub-scanning direction between adjacent recording elements in one recording element row. .

The printing head scans in the main scanning direction to perform printing. After printing is completed by one printing scan, the printing medium is moved by N × M × D in the sub-scanning direction.
Image recording is performed by repeating the recording scan in the main scanning direction and the movement of the recording medium in the sub-scanning direction.

[0012]

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

FIG. 1 is a plan view showing the arrangement of the recording elements of the recording head 101 in the image recording apparatus according to the first embodiment of the present invention.

In this image recording apparatus, the pixel interval D in the sub-scanning direction is M × D with respect to the pixel interval D at the recording resolution.
A matrix type comprising M printing element arrays having the same configuration in which a plurality of printing elements are arranged, wherein the number N of printing elements is larger than the number M of printing element rows, The relative distance of the column in the sub-scanning direction is M × D
A print head 101 arranged longer and shorter than N × M × D scans in the main scanning direction to perform printing, and after printing by one printing scan is completed, the printing medium is moved to N × M × D in the sub-scanning direction. The image is recorded by moving the recording medium by M × D and repeating the recording scan in the main scanning direction and the movement of the recording medium in the sub-scanning direction.

In this embodiment, the recording head 1
01, the number M of the recording element arrays 103 is 4, and in each of the recording element arrays 103, N recording elements 102 are arranged at 4D intervals in the sub-scanning direction. Then, the shift amount of each recording element array 103 in the sub-scanning direction is d_0 = 19D,
d_1 = 13D and d_2 = 6D.

The print scan pattern in one print scan using such a print head 101 is shown in FIG.
This is like the recorded image S0 in (a). Then, the pattern of the next print scan after this print scan S0 becomes like the print image S1 in FIG. 2A because the print medium moves N × M × D, and eventually the print images S0 and S1 are When overlapped, as shown in a print image S0 + S1 in FIG. 2B, the print scan S1 complements a line not printed by the print scan S0 in the overlap area. At this time,
As shown in FIG. 20A, even when the image recording is performed with dots smaller than other portions due to poor characteristics at both ends of each recording element row, the recording result in the sub-scanning direction at the end of the recording scan is 20 (b), and the end portion of the recorded image in one recording scan is as shown in FIG. As a result, the recorded image at the boundary indicated by a-S01 in FIG. 12 is as shown in FIG. 22, and the thinning processing is performed without performing the thinning processing (banding processing) of the image data accompanied by the decrease in the recording speed. The same effect as described above can be obtained.

FIG. 3 is a block diagram of a control device in an image recording apparatus for realizing such image recording. The image recording apparatus according to this embodiment includes an image processing apparatus 30.
0, a printer engine 310, and an operation panel 320.

The image processing apparatus 300 includes a CPU 301,
Program ROM 302 and external I / F control circuit 303
, Main memory 304, engine I / F control circuit 3
05 is connected by a bus 306.

The operation panel 320 is connected to the CPU 301 via the I / F 321.

As shown in FIG. 4, the printer engine 310 scans a print head block 401 (printing element arrays are aligned as shown in the print head 101 of FIG. 1) along a guide 402 in the main scanning direction to print. A band-shaped recording is performed on the medium 403, and after the recording scan in the main scanning direction, the recording medium 403 is moved in a sub-scanning direction orthogonal to the main scanning direction,
Image recording is performed by repeating the recording scan in the main scanning direction and the movement of the recording medium in the sub-scanning direction.

The recording head 101 has an interval M in the sub-scanning direction.
A matrix-type print head comprising M print element rows having the same structure in which N print elements are arranged in × D, and the number N of print elements is larger than the print element row M; The arrangement is such that the relative distances in the sub-scanning direction of all the printing element rows in the row are multiples of D and longer than M × D and shorter than N × M × D.

A print head block 401 according to this embodiment performs printing scan in the main scanning direction and print medium 403.
Is repeated in the sub-scanning direction to complete image recording. An engine control circuit 311 for controlling these operations is controlled by an engine I / F 312 via an I / F 312.
Connect to the control circuit 305.

The external I / F control circuit 303 of the image processing apparatus 300 connects to a host computer, a network, and the like via the I / F 307.

As shown in FIG. 5, the image processing apparatus 300 secures two L-line data areas to be printed by one printing scan on the main memory 304, and stores them in a line buffer area # 0 and a line buffer area # 0. The area # 1 is set, and three or more reception buffer areas for receiving image data with one L line as a unit are secured and set as the reception buffer area. The image processing apparatus 300 includes the external I / F control circuit 3
First, the image data sent via the data buffer 03 is stored in the reception buffer area # 0 on the main memory 304. When the reception of the image data sent via the external I / F control circuit 303 to the reception buffer area # 0 is completed, the reception (storage) destination of the image data is changed to the next reception buffer area (reception buffer area # 1). And the transfer of the image data in the reception buffer area # 0 to the line buffer area # 0 is started. At this time, the data to be transferred does not mean that all the L lines of the reception buffer area # 0 are sent.

Here, as shown in FIG.
01, C_0, C_1,... C_M−
Assuming that the n-th printing element array is C_n and the shift amount in the sub-scanning direction between the printing element array C_n and the printing element array C_M-1 is d_n (d_0, d_1,..., D_M-2), d_n becomes It can be expressed by the following equation.

D_n = a_n × M × D + b_n × D where a_n is 0 <a_n <N, a_n> a_n +
It is an integer that is 1, and for b_n, 0 <b_n <
M is an integer and a_a for each recording element array C_n
n and b_n do not take the same values as those of the other printing element arrays. As for b_n, all integers from 1 to M-1 are applicable to any of b_n.

For example, in FIG. 1, M = 4, N = 1
6, d_0 = 19D, d_1 = 13D, and d_2 = 6D, a_n and b_n are as follows. d_0 = 19D, a_0 = 4, b_0 = 3 d_1 = 13D, a_1 = 3, b_1 = 1 d_2 = 6D, a_2 = 1, b_2 = 2 At this time, the recording element array in the reception buffer area # 0 of the L line The image data to be sent to C_n is a recording element # N-1.
From the side, Na_n lines are set, and the image data of the a_n lines from the printing element # 0, which is the image data outside the area of the reception buffer area # 0, is sent as image data indicating a blank, and a total of N lines are provided for each printing element row. Of image data.
For the printing element array C_M-1, image data of all N lines, which is the same as the number N of printing elements in the printing element array, is sent from the reception buffer area # 0. As described above, image data of N lines is sent to each recording element row including image data indicating blank, and image data for a total of L lines is transferred to the line buffer area.

After the transfer processing of the image data of the first L lines to the line buffer area # 0 is completed, the transfer destination of the image data is changed from the line buffer area # 0 to the line buffer area # 1, and the printer engine 310 Is notified that data transmission is possible.

Here, if the reception of the image data to the reception buffer area # 1 has been completed, the image data of the overlap area of the reception buffer area # 0 not recorded in the previous recording scan and the next reception buffer The transfer process of the image data of the L line in the area # 1 is started, and if not completed, the process waits until the reception of the image data to the reception buffer area # 1 is completed, and after the reception of the data to the reception buffer area # 1 is completed. The image data transfer process starts. In the data transfer process at this time, the image data to be sent to the printing element array C_n in the reception buffer area # 1 is N data from the printing element # N-1 side.
-A_n lines, the remaining a_n lines of image data send image data of the overlap area of the reception buffer area # 0, and send a total of N lines of image data to each recording element row. For the printing element array C_M-1, image data of all N lines, which is the same as the number N of printing elements in the printing element array, is transmitted from the reception buffer area # 1. After the transfer processing to the line buffer area # 1 is completed, the reception buffer area # 0 becomes a reception buffer area for receiving the next image data after the reception buffer area # 2 has completed the reception of image data. . Data transfer processing is similarly performed for the image data of the L lines thereafter. When the reception of all the recording image data to the reception buffer area is completed, the data transfer processing is performed until the data transfer to the line buffer area of all the image data in the reception buffer area is completed.
For lines without image data, image data indicating blank is sent.

Upon receiving the notification that data transmission is possible, the printer engine 310 requests the image processing apparatus 300 to transmit image data.

The image processing apparatus 300 transfers the image data from the line buffer area # 0 in accordance with the image data transmission request from the printer engine 310. The printer engine 310 sends the print head block 401 based on the received image data. Is moved in the main scanning direction to perform image recording (recording scan) on the recording medium 403. After one printing scan, the printing medium 403 is moved N × in the sub-scanning direction.
Move M × D. At this time, the recording head block 40
1 does not return to the original position, and in the next print scan, the print scan is performed by moving in the direction opposite to the previous print scan.

The timing of the printing operation of the printing element during printing scanning is controlled according to the position of the printing element in the main scanning direction. Thus, as in the recording head 101 having the arrangement of the recording elements as shown in FIG. 1, the recording head having the arrangement of the recording elements as shown in FIG. 9, and the recording head having the arrangement of the recording elements as shown in FIG. In addition, it is possible to cope with an arrangement in which the arrangement of recording elements in the main scanning direction is different. The print head 104 shown in FIG. 9 is a print head in which the print elements 105 are arranged obliquely in the main scanning direction to form a print element array 106, and the print head 107 shown in FIG. A print head 108 is configured in a zigzag manner (sawtooth shape) while being shifted in the main scanning direction to form a print element array 109, and G is a shift amount.

The above-described image data reception processing, transfer processing, and data transfer processing to the printer engine are apparently performed simultaneously by multitask control.

FIG. 6 shows a timing chart of these operations. As shown in FIG. 6, it is assumed that the transfer processing of the image data of the L line is completed in a time shorter than the time required for one print scan of the print head block 401. The time required for the reception processing of the image data of the L line is t1, the time required for the transfer processing is t2, the time required for one print scan of the print head block 401 is t3, and the time for the print head block 401 to perform the print scan. To t4
Then, it is sufficient to satisfy the relationship of the following equation. t1 <t3 + t4 t2 <t3 + t4

FIG. 7 shows an outline of a reception buffer area in this embodiment, and FIG. 8 shows an outline of a line buffer area.

The line buffer area is divided into M blocks and managed using N lines as one unit. The data transfer from the reception buffer area to the line buffer area is performed in the order of the printing element arrays. The data of the printing element array C_0 is block 0, the data of the printing element array C_1 is block 1, and so on. To be stored.

The image data of each printing element row extends over two reception buffer areas except for the printing element row C_M-1. As shown in FIG. 7, assuming that a reception buffer area where data reception is completed is a reception buffer area x + 1, and a reception buffer area where data reception is completed one time before is a reception buffer area x, the reception buffer area is a block 0 of the line buffer area. Among the image data of the recording element array C_n to be transferred, the image data sent from the reception buffer area x is a
_N lines, and the image data sent from the reception buffer area x + 1 is Na-n lines. At this time, the leading line R_n0 of the image data sent from the receiving buffer area x is represented by the following equation, assuming that the leading line of the L line receiving buffer area is 0. R_n0 = L− (a_n × M + b_n) −1 Therefore, the line R_nm of the image data for the m-th printing element in the printing element array C_n is as follows. R_nm = R_n0 + M × m Here, when the value of R_nm becomes larger than L,
The value of R_nm-L is applied to the reception buffer area x + 1. In this way, the lines of the image data to be transferred are obtained, and the image data for N lines is transferred line by line from the reception buffer area to the line buffer area. This process is performed M times, which is the number of printing element rows, to complete the data transfer process from the receiving buffer area to the line buffer area.

When the recording resolution is increased by a factor of H, recording is performed using an interlace method in which the amount of movement of the recording medium in the sub-scanning direction is controlled in D / H units. In this case, the moving amount of the recording medium in the sub-scanning direction may be such that the sum of the moving amounts of H times is N × M × DD / H. Here, the movement amount of the m-th recording medium is represented by y
_M (y_0, y_1, ... y_H-1), y_
m can be represented by the following equation. y_m = j_m × M × D + k_m × D / H Here, j_m is an integer satisfying 0 ≦ j_m <N,
k_m is an integer satisfying 0 ≦ k_m <H,
K_m with respect to the movement amount y_m of the m-th recording medium is:
They do not take the same value.

By moving the recording medium in the sub-scanning direction in this way, it is possible to cope with a case where the recording resolution is increased H times.

[0040]

According to the present invention, in a serial type image recording apparatus, when recording is performed with a part of the recording scan overlapped, the recorded images by the recording elements at both ends of the recording element row are overlapped. By dispersing in the area, the switching between printing scans is performed gradually without focusing on one place, so that the switching of the printed image becomes ambiguous and banding becomes difficult to be recognized, and the image signal accompanied by a reduction in the printing speed is reduced. The same effect as the thinning processing can be obtained without performing the thinning processing.

[Brief description of the drawings]

FIG. 1 is a layout diagram of recording elements of a recording head in an image recording apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing recording scanning in the image recording apparatus according to one embodiment of the present invention.

FIG. 3 is a block diagram of a control device in the image recording apparatus according to the embodiment of the present invention.

FIG. 4 is a perspective view showing the configuration and operation of a serial printer engine.

FIG. 5 is an explanatory diagram schematically showing a reception buffer area and a line buffer area configured in a main memory of the image processing device of the image recording apparatus according to the embodiment of the present invention;

FIG. 6 is an operation timing chart of the image recording apparatus according to the embodiment of the present invention;

FIG. 7 is an explanatory diagram illustrating a reception buffer area configured in a main memory in the image processing device of the image recording device according to the embodiment of the present invention;

FIG. 8 is an explanatory diagram showing a line buffer area configured in a main memory in the image processing device of the image recording apparatus according to one embodiment of the present invention.

FIG. 9 is a plan view showing a modified example of a recording element array in the recording head of the image recording apparatus according to the embodiment of the present invention.

FIG. 10 is a plan view showing a modified example of a recording element array in a recording head of an image recording apparatus according to an embodiment of the present invention.

FIG. 11 is a layout diagram of recording elements of a recording head in a conventional image recording apparatus.

FIG. 12 is an explanatory diagram showing a recording result of a conventional serial type image recording apparatus.

FIG. 13 is an explanatory diagram showing overlap of recording scans of a conventional serial type image recording apparatus.

FIG. 14 is an explanatory diagram illustrating an example of a print image obtained by one print element array of a print head.

FIG. 15 is an explanatory diagram illustrating an example of a recorded image in a sub-scanning direction in a conventional image recording apparatus.

FIG. 16 is an explanatory diagram illustrating an example of a boundary portion of a printing scan when banding processing is not performed in a conventional image printing apparatus.

FIG. 17 is an explanatory diagram illustrating an example of a boundary portion of a printing scan when banding processing is not performed in a conventional image printing apparatus.

FIG. 18 is an explanatory diagram illustrating an example of a boundary portion of a printing scan when a thinning process is performed in a conventional image printing apparatus.

FIG. 19 is an explanatory diagram illustrating an example of a boundary portion of a printing scan when a thinning process is performed in a conventional image printing apparatus.

FIG. 20 is an explanatory diagram illustrating an example of a recorded image in the sub-scanning direction in the image recording device according to an embodiment of the present invention.

FIG. 21 is an explanatory diagram illustrating an example of a boundary portion of a printing scan in the image printing apparatus according to an embodiment of the present invention.

FIG. 22 is an explanatory diagram illustrating an example of a boundary portion of a printing scan in the image printing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

101 print head, 102 print element, 103 print element array, 300 image processing apparatus, 301 CPU, 30
2. Program ROM 303: External I / F control circuit
304: Main memory, 305: Engine I / F control circuit, 306: CPU bus, 307: External I / F, 310
... Printer engine, 311 ... Engine control circuit, 31
2 engine I / F, 320 operation panel, 321 panel I / F, 401 recording head block, 402 guide, 403 recording medium.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiji Kunimi 1060 Takeda, Hitachinaka-shi, Ibaraki Prefecture Inside Hitachi Koki Co., Ltd. Reference) 2C056 EA08 EC03 EC07 EC12 EC71 EC74 FA10 HA22 2C062 KA03 KA05

Claims (6)

[Claims] 1. A printing head scans a printing medium in a main scanning direction based on image information to perform printing on a printing medium in a belt shape. After the printing scanning, the printing medium is moved in a sub-scanning direction orthogonal to the main scanning direction. In a serial recording type image recording apparatus that completes image recording on a recording medium by alternately repeating the recording scanning in the main scanning direction and the movement of the recording medium in the sub-scanning direction, the recording head includes a plurality of recording heads. A plurality of printing element rows having the same structure in which the printing elements are arranged in the sub-scanning direction. Each of the printing element rows has a pixel spacing in the sub-scanning direction of the printing elements and a row of the printing element row in the printing resolution. A plurality of the printing elements are arranged so as to be a product of the numbers, and the printing elements are configured in a matrix type in which the number of printing elements in one printing element row is larger than the number of printing element rows. Sub-scanning direction relative distance between the recording element array of Te is a multiple of the sub-scanning direction between the pixels to be recorded,
The number of printing elements in one printing element row and the spacing in the sub-scanning direction of adjacent printing elements in one printing element row are longer than the spacing in the sub-scanning direction between adjacent printing elements in one printing element row. The image recording apparatus is arranged so as to be shorter than the product of: 2. The printing method according to claim 1, wherein the amount of movement of the printing medium in the sub-scanning direction during printing scanning is determined by the number of printing elements in one printing element row and the number of adjacent printing elements in one printing element row. An image recording apparatus, wherein the product is a product of an interval in a sub-scanning direction. 3. The method according to claim 1, wherein the control is performed in units of pixel intervals of a print resolution obtained by multiplying the amount of movement of the recording medium in the sub-scanning direction by an integer, and an image is printed with an integer multiple of the print resolution using an interlace method. An image recording apparatus, comprising: 4. An image recording apparatus according to claim 2, wherein all the recording elements of the recording element array are arranged on a straight line in the sub-scanning direction. 5. An image recording apparatus according to claim 2, wherein all the recording elements of the recording element array are arranged on a straight line having a certain angle with respect to the sub-scanning direction. . 6. The printing head according to claim 2, wherein the printing heads are arranged such that a plurality of printing elements in a printing element row are shifted by an arbitrary distance from a certain reference position in a main scanning direction, and this is repeated. An image recording apparatus wherein all recording elements are arranged.