JPS6395781A - Color image recording method - Google Patents

Abstract

PURPOSE:To suitably prevent a color smear by adding a correcting dot discretely to raster data, increasing and decreasing the correcting dot in accordance with the width size changing information of a recording paper during the recording and recording it. CONSTITUTION:The correcting dot is added discretely for raster data, for example, for a unit data block for several-several tens of bits each to constitute the raster data, for example, at the rate of 1-several bits, the correcting dot is increased decreased in accordance with the width size changing information of a recording paper during the recording and the recording is executed. When second and third color images are overlapped and formed and the width of the recording paper is contracted, for example, by drying, the size of the image formed first comes to be small. On the other hand, for the recording of the second and third succeeding color images, the correcting dot is removed based on the changing information of a recording paper width, and the recording is executed based on the raster data of the length in which the length matches with a first color image size. Thus, even when the elapsed size change occurs at a recording paper, the generation of the color smear can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to receiving raster data and recording it on a recording paper using a line recording head. The present invention relates to a color image recording method in which images of different colors are superimposed and recorded on the same recording paper surface while being relatively moved in a direction.

[Conventional technology]

In recent years, various color image recording methods have been developed and put into practical use, but one of the most common methods is to move the recording paper and line recording head relative to each other in a direction perpendicular to the line recording direction. , different colors on the same recording paper,
For example, C (cyan), M (magenta), Y (yellow)
There is a method of recording and forming images in three colors by superimposing them. The order in which the color images are superimposed in this case varies depending on the configuration of the device, but is often fixed in the order of C, M, Y or Y, M, C. The reason why this order is fixed is because the next pixel is painted over the pixel that will become the base, so if the order changes, the power and color will change due to the relationship between the reflectance and transmittance of the coloring material used. This is because the balance changes. Another cause of this color balance is misalignment between pixels. For example, when painting C (2M), as shown in Figure 5 (a) and (b), if each pixel completely overlaps, B (BLU
E). However, if each pixel is shifted, Figure 6(a) (
As shown in b), the result is C+M+B (BLUE). Furthermore, if the amount of misregistration increases, the image forming position of each color will be significantly distorted, making it impossible to perform normal image formation. In this way, in color image recording,
Pixel alignment is an important issue.

As a positioning means for color image recording, for example in color printing, positioning cross marks commonly called "tonbo" are placed outside the printing area, for example at the closing margin, C, M.
, Y, and B, and adjust the paper feed of the device so that the cross marks match to align the positions. On the other hand, in a line recording type color image recording device, in order to automatically perform the above-mentioned positioning, a positioning mark called a "timing mark" is recorded, for example, before recording the required image, and the positioning mark is A device has been put into practical use that detects the misalignment of recording paper by reading the information, and performs alignment.

FIGS. 7 and 8 are examples. In FIGS. 7 and 8, 1 is a roll of recording paper, 2 and 3
is a sensor that detects the relative position of the recording head and recording paper in the X-axis direction. As this sensor 2.3, a sensor array such as a COD close-contact line sensor whose output is turned on and off depending on the presence or absence of an edge of the recording paper 1 is used. It can be detected in small units.

Reference numerals 4 and 5 denote reflective 1-bit sensors, which detect the position of the recording paper 1 in the Y-axis direction by a method described later. Further, 6 and 7 are rollers. Although not shown, a motor is attached to the recording paper 1 and the roller 7, so that the recording paper 1 can be transported in the left and right directions in the figure. An encoder 8 is attached to one end of the roller 6 so that the amount of conveyance of the recording paper 1 can be detected.

The controller 9 shown in FIG.
Convert vector data such as AD to Lascue data,
It is sent to the recording circuit 10. A recording circuit 10 supplies raster data to a recording head 11. The recording head 11 is a unit for recording and forming an image on the recording paper 1, and includes, for example, an inkjet head, a thermal head, a ribbon, an electrostatic recording head, a developing device, etc.
This is a so-called line recording head that can record raster data.

In the case of the apparatus shown in FIGS. 7 and 8, before or at the same time as recording an image of the first color, positioning is applied to both ends of the recording paper 1 that are outside the image area to be recorded. Record timing marks 12 and 13. After the recording paper 1 is rewound once, when the timing marks 12, 1B are first detected by the sensors 4, 5, raster data is received from the controller 9, and required image recording is started. Thereafter, the writing position is controlled using the timing marks 12 and 1B.

For example, if the recording paper 1 deviates in the X-axis direction after starting recording, the sensors 2 and 3 detect the deviation 2. Then, positioning in the X-axis direction is performed by shifting the recording end position of the data sent in accordance with the amount of shift. Also, regarding the Y-axis direction, sensor 4.
The amount of skew of the recording paper 1 is detected from the time difference between the signals output by the recording paper 5. By calculating the sent raster data based on the detected skinny amount, the recording position is skewed by the raster data, and the recording head and paper feeding system are adjusted to perform positioning.

[Problem that the invention seeks to solve]

Although the above-described positioning means is effective against misalignment of the recording paper 1 in its running, it has the following problems.

When the recording medium is paper, its dimensions change due to changes in humidity. For example, when humidity increases, paper tends to stretch, and when humidity decreases, paper tends to shrink.

Therefore, if a change in humidity acts on the recording paper during recording, a positional shift occurs in the recorded image. For example, using recording paper 1 whose humidity has been adjusted to balance the relative humidity at 60% at the time of manufacture, C.
Assuming that images are recorded in the order of M, Y, the widths of the recording paper 1 are Wl, W2, . . . as shown in FIG. Like W3, it gradually contracts.

Therefore, even if an image is recorded accurately on the same line, the image at the end of recording will have a recording width W on the recording head.
On the other hand, as shown in the figure, the values become smaller in the order of <Y, M, and C.

In order to solve this problem, the sensors 2 and 3 shown in FIGS. 7 and 8 are used bare to detect the dimensional change of the recording paper 1 in the By thinning out the raster data at regular intervals,
An image recording method that matches the axial dimension has been considered. However, according to this recording method, since a portion of the raster data that is sent is thinned out, there is a risk that important image data located at the thinned out position may be lost. For example, when there is a straight line to be recorded along the feeding direction of the recording paper, there is a problem that the line disappears without being recorded.

Therefore, the present invention can accurately prevent color shift caused by dimensional changes in the width direction of the recording paper even for recording paper whose humidity is balanced to 50 to 60% I11 vs. An object of the present invention is to provide a color image recording method that does not cause data loss.

[Means for solving problems]

In order to solve the problems and achieve the objectives of the present invention,
The following means? It was 1ζ. That is, raster data is received and recorded on the recording paper by the line recording head, and while the recording paper and the line recording head are relatively moved in a direction perpendicular to the line recording direction, different data are recorded on the same recording paper surface. In a color image recording method in which color images are recorded and formed by superimposing them, raster data is discretely recorded, for example, for each unit data block of several to several tens of bits constituting the raster data. Correction dots are added at a certain rate, and recording is performed while increasing or decreasing the correction dots in accordance with information on changes in the width of the recording paper during recording.

[Effect]

By taking such measures, the following effects are achieved. When recording an image of the first color, there is relatively little change in the width of the recording paper, so the recording paper has approximately the normal width, and the recorded image also has the normal size. This 1-
Second. If the width of the recording paper shrinks due to drying, for example, when the third color image is superimposed and formed, the size of the initially formed image becomes smaller. However, the subsequent second. Image recording for the third color is performed by removing correction dots based on information on changes in the width of the recording paper, and based on raster data whose length matches the image dimensions of the first color. Even if dimensional changes occur over time,
It is possible to prevent color shift from occurring. In this case, since the correction dots added in advance are removed, even if the correction dots are removed, no part of the true image is lost, and the image content is not altered.

If the width of the recording paper expands due to moisture absorption during recording, the number of correction dots is increased in the opposite manner to the above, and color misregistration is similarly prevented.

〔Example〕

FIG. 1 is a block diagram showing an example of an apparatus for carrying out the method of the present invention. In the figure, numeral 21 is a raster data generating section, which supplies computer-generated information such as vector data of CAD or computer graphics, or document information such as photographs and calligraphy. A receiving buffer 22 receives the raster data. 23 is its write address circuit;
24 is its read address circuit. Reference numeral 25 denotes a read buffer, which sequentially reads out the raster data received by the receiving buffer 22.

Reference numeral 26 denotes a bit string expansion circuit, which applies correction dots, that is, dummies, to the raster data discretely, for example, at a rate of 1 to several bits, for example, for each unit data block of several to several tens of bits that make up the raster data t7i. It has the function of obtaining raster data of a predetermined length by adding bits.

Note that it is desirable that the dummy bits correspond to the state of adjacent bits at the location where they are added in order to avoid image deterioration. In other words, when black and white binary recording is used and signals of "1" and "0" are used, if both the front and rear of the dummy bit are "1", the signal to be added is "1"; If both are "0", add "0". In addition, in boundary areas where the front and back are "1" and "0" or "0" and "1", add a dummy bit that is the same as either the front bit or the rear pit, or add a dummy bit that is the same as the front bit or the rear pit, or Try to add a bit of intermediate nature. For example, 5 dummy bits can be inserted for each data line.
The specified insertion position may be shifted within the range of 0 to 200 bits to make the effect of the insertion less noticeable.

27 is a bit string reduction circuit, and 28.2 will be explained next.
Based on the information on changes in the width dimension of the recording paper during recording, which is obtained by step 9, etc., the correction dots, ie, dummy bits, are removed as necessary to reduce the bit string.

The paper size data generation section 28 is for generating size data of the recording paper, and is of a type that directly detects the size of the recording paper by a detection circuit including a position sensor in the width direction of the recording paper, or is of a type that simply detects the size of the recording paper. For example, a method is used in which a number of stages of predicted values of dimensional changes are prepared and these are selectively input.

The M small controller 29 is a paper size data generator 28
This is for specifying the location where the dummy bit is to be removed according to the information from the bit string expansion circuit 26.

Thus, when there is no reduction in the recording paper width, no dummy bits are removed, when there is a severe reduction, a small number of dummy bits are removed, and when there is a large reduction, a large number of dummy bits are removed. In this way, as the recording paper width decreases, the number of dummy bits to be removed is increased to maximize the bit string expansion circuit 2.
It is now possible to remove up to the number of dummy bits inserted in step 7.

Reference numeral 30 denotes an output buffer, in which raster data whose bit string has been reduced in accordance with the reduction in the width of the recording paper is directly converted from serial to parallel and sent to the latch circuit 31. The latch circuit 31 sends parallel raster data to the head drive circuit 32. The head drive circuit 32 records the data on recording paper.

FIG. 2 is a diagram showing a specific circuit configuration of the image enlarging section centering on the bit string enlarging circuit 26. As shown in FIG. In the figure, 51 is a latch circuit, 52 is a parallel-to-serial conversion circuit, 53 and 54 are shift registers, 55 and 56 are interlocking changeover switches, 57 is a flip-flop circuit (hereinafter abbreviated as FF circuit), 58 is a counter, 59.degree. 64 is an OR gate, 60 is a polarity inversion circuit, 61.degree. 63 is an AND gate, and 62 is an AND gate with a negative circuit.

Hereinafter, the operation of the circuit shown in FIG. 2 will be explained with reference to the operation timing chart shown in FIG. 3 at appropriate times. Here, an example will be explained in which one line is divided into unit data blocks of 8 bits and processed.

When the write signal WR is applied at time t1 shown in FIG. 3, the image data FD read out from the reception buffer 22 shown in FIG. 1 is held in the latch circuit 51 by the write signal WR. At the same time, the FF circuit 57 is set by the write signal WR, and at the same time,
Counter 58 is cleared.

As a result of setting the FF circuit 57, the gate 61 is opened by the set output signal SO, and the clock signals Sl and S4 are opened.
is supplied. The shift operation of the shift register 53 is started by the clock signal S4.

On the other hand, as a result of the counter 58 being cleared, the counter 58
The Qmax output of becomes zero. Therefore, the gate 62 is opened and the clock signal S1 is supplied to the parallel-to-serial converter circuit 52 as the shift clock signal S2. Therefore, the parallel-to-serial conversion circuit 52 starts operating and starts converting the parallel raster data latched by the latch circuit 51 into serial raster data. The converted serial data is sequentially supplied to the shift register 53.

The clock signal S1 that has passed through the gate 61 is supplied to the counter 58. Therefore, the counter 58 starts counting operation. As a result, the number of bits serially transferred from the parallel-to-serial conversion circuit 52 to the shift register 53 is counted.

When the 8th bit is transferred at time t2 shown in FIG.
The ax output becomes "1". Therefore, the gate 62 is closed,
Since the clock signal S2 is cut off, the parallel to direct conversion circuit 52
will stop while maintaining that state. However, at this point, the gate 63 is still closed, so the clock signal S3 is not sent out. Therefore, the FF circuit 57 remains set and the gate 61 remains open. Therefore, the shift register 53 receives the clock signal S.
4 will be further man-powered and serial man-power will continue. That is, the last data of the parallel-to-serial conversion circuit 52 continues to be input to the shift register 53.

Dummy bits are added to the transferred data in this way, and the image data FD is enlarged.

In this embodiment, after the parallel-to-direct conversion circuit 52 stops,
Time t when the counter 58 counts the next clock signal S1
3, both the QA and Qmax outputs of the counter 58 become "1", so the gate 63 opens and the pulse signal S
3 is sent. Therefore, on the one hand, the FF circuit 57
is reset, and on the other hand, counter 58 is cleared.

When the FF circuit 57 is reset, the gate 61 closes,
Shift register 53. Counter 58. Clock signal S4. which was being supplied to gate 62. Sl is cut off. At the same time, the write enable signal WREN is outputted to the latch circuit 51 through the polarity inversion circuit 60, so that the write operation is completed and the next data is in a standby state.

In this way, one dummy bit is added to the 8 bits of the manually generated image data FD, and the image data F
D is enlarged. By repeating the above operation a predetermined number of times, enlarged image data in which one bit is added to each 8-bit unit data block is obtained.

Note that a shift register 54 is arranged parallel to the shift register 53 via changeover switches 55 and 56. Therefore, by switching the changeover switches 55 and 56 at the same time, during the period when one shift register 53 is being written, the other shift register 53 is
4, and while a write operation is being performed on the other shift register 54, reading can be performed from one shift register 53. the result,
Not only can the bit string expansion operation be performed efficiently, but it can also be operated asynchronously with the image reduction circuit in the next stage.

FIG. 4 is a diagram showing a specific circuit configuration of the image reduction section centering on the bit string reduction circuit 27. 70 in Figure 4
3 shows a state in which one of the shift registers 53 or 54 in the circuit of the image enlarger shown in FIG. 3 is electrically separated from the circuit shown in FIG. 2 and taken out. 71 and 72 are shift registers similar to the shift register 70 described above, and two of them are arranged in parallel for the same reason as in the case of FIG. 73
is a serial-to-parallel conversion circuit. 74.75 and 76°7
Reference numeral 7 designates an interlocking changeover switch for switching between the two shift registers 71 and 72.

78 is a counter that outputs a pulse every 8 clocks, and 79 is a counter that outputs a pulse every 9 clocks. 80, when the preset value set in advance becomes zero,
It is a subtraction counter that sends out an output "1". 81 is the first
The bit string enlarging circuit 2
This is a decoder that forms data for determining how many blocks to remove correction dots, that is, dummy bits added to each 8-bit unit data block in 6, and corresponds to the reduction controller 29 in FIG. ing. The contents of this decoder 81 become preset data for the subtraction counter 80. 82 is an AND gate with a negative circuit, 8
3 is an AND gate, and 84.85 is an OR gate.

Next, we will explain the operation of a circuit configured like two legs.

When the one-line start signal LINE-START is input manually, the counters 78 and 79 are reset and a preset command signal is given to the subtraction counter 80, so that the contents of the decoder 81 are preset to the counter 80.

Now, assuming that the amount of shrinkage of the recording paper is extremely large, data [1] is set in the decoder 81 in accordance with the large width dimension change information in order to remove all dummy bits from all unit data blocks. Ru. If the amount of shrinkage of the recording paper is relatively small, 2, 3. ... to remove dummy bits for each block [2].

[3]...The following data is set.

When the transfer lock CLK is manually activated, the shift register 70
data begins to be sequentially transferred to the shift register 71. At the same time, counters 78 and 79 start counting the number of clocks, that is, the number of transfers.

When the transfer of 8 bits is completed, the count value of the counter 78 becomes [8], so one pulse is output. When this pulse is input to the subtraction counter 80, [1] preset in the subtraction counter 80 is subtracted to become [0]. Then, the output "1" is sent from the counter 80 and the gate 82 is closed. Therefore, the clock signal that had been supplied to the shift register 71 is cut off, and the shift register 71 stops. However, since the clock signal continues to be supplied to the shift register 70, the shift register 70 further performs a shifting operation. As a result, the ninth dummy bit added earlier is not transferred to the shift register 71 and is discarded. In other words, dummy bits are removed. When the shift of the 9th bit is completed, the count value of the counter 79 becomes [9], so one pulse is output. Since this pulse is given as a clear signal to the counter 78 via the OR gate 84, the counter 78 is cleared.

Further, the pulse is applied to an AND gate 83 and an OR gate 8.
5 to the subtraction counter 80 as a preset command signal. Therefore, the subtraction counter 80 and the decoder 8
The setting data based on 1 is preset again. At this point, the naori counter 79 is in its initial state, that is, in its clear state. Then, the above-described series of operations is repeated again. In this way, all the dummy bits added to each data block are removed, and one line of raster data is reduced to the length before adding the dummy bits.

Note that if the shrinkage of the recording paper is not so large and the value preset in the subtraction counter 80 is a large value of [2] or more, the content will not become zero even at the end of 8-bit transfer. In other words, its output remains "0". Therefore, in such a case, since the gate 82 remains open, the 9th bit is also transferred to the shift register 71. When this transfer is completed, the counters 78 and 79 are cleared and the subtraction counter 80 is re-preset as described above. The same operation is repeated below. When the contents of the subtraction counter 80 become zero, the dummy bits are removed in the same way as described above. In this way, since the dummy bits are removed one bit at a time for each of a plurality of data blocks, the degree of raster data reduction in this case is relatively small.

The data stored in the shift register 71 is electrically disconnected from the circuit shown in FIG. 4 by the switching operation of the changeover switch group, and is reconverted into parallel data in the direct/IP column conversion circuit 73. Afterwards, it is sent to the next stage circuit.

Next, a case where the present embodiment described in 1-1 is applied to the conventional apparatus shown in FIGS. 7 and 8 will be described. When rolled recording paper 1 is rolled up, it has the same moisture content as when it was manufactured, but in the process of being unrolled and transported to the recording section, the width dimension changes depending on the environmental humidity.

This change in the width of the recording paper 1 is detected by edge sensors 2, 3 or timing mark sensors 4.5.

When detected by the edge sensor 2.3, recording width control is performed from the time of recording the first color. Further, in the case where the timing marks are detected by the timing mark sensors 4 and 5, the timing marks 12 and 1.3 are first recorded, and then recording width control is performed from the next step. Changes in the width of the recording paper 1 occur rapidly for several minutes after the recording paper 1 is unwound from the roll, and after 5 to 10 minutes have passed and it has become accustomed to the environment, the change becomes quite gradual.

The humidity of the recording paper 1 is often adjusted during manufacturing so that the relative humidity is normally balanced at 50 to 60%, but the relative humidity is usually 20 to 30%.
When placed unrolled in an environment with a relative humidity of 0.
Shrinkage in the width direction of about 5% occurs. Therefore, the second color,
As the third color and the third color are printed, printing is performed while increasing the amount of correction of the printing width. The correction amount is determined in real time by directly detecting the edge of the recording paper 1 or by detecting the timing marks 12 and 13. When the timing marks 12, 13, etc. are only partially arranged, the dimensional information between the marks is supplemented by calculation. Furthermore, if there is no mechanism for detecting the recording paper width, the present invention can be carried out by predetermining the same type of correction conditions, selecting them as appropriate, and inputting them into the correction circuit. It is.

Note that the present invention is not limited to the above embodiments. For example, in the above embodiment, the bit string reduction circuit 27 is provided assuming that the recording paper shrinks due to drying during recording, but it is also possible to deal with the case where the width of the recording paper expands due to moisture absorption. Additionally, a bit string expansion function similar to that of the bit string expansion circuit 26 may be added to the bit string reduction circuit 27. In addition, the recording device has a secret structure,
In addition, if a dehumidifying means is incorporated to prevent the recording environment from becoming highly humid, the above embodiment can be conveniently used even in a highly humid recording environment. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, correction dots are added discretely to raster data, for example, at a rate of 1 to several bits, for each unit data block of several to several tens of bits constituting the raster data, and the correction dots are recorded. Since recording is performed while increasing or decreasing the correction dots according to the width dimension change information of the recording paper inside, the recording paper can be recorded even if it is moistened by 1 liter to balance the relative humidity of 50 to 60%. It is possible to provide a color image recording method that can appropriately prevent color shift caused by dimensional changes in the width direction of recording paper and that does not cause the risk of image data being lost.

[Brief explanation of the drawing]

Figures 1 to 4 are diagrams showing one embodiment of the present invention. Figure 1 is a block diagram showing an example of a device for carrying out the method of the present invention, and Figure 2 is an image centered on the bit string expansion circuit. FIG. 3 is a diagram showing the operation timing of FIG. 2, and FIG. 4 is a diagram showing the specific circuit configuration of the image reduction section, centering on the bit string reduction circuit. Figure 5 (
a)(b) and FIGS. 6(a) and (b) are diagrams explaining problems in the prior art, FIGS. 7 and 8 are diagrams showing examples of conventional devices,
FIG. 9 is a diagram showing a pattern of color misregistration, which is a drawback of the conventional apparatus shown in FIGS. 7 and 8. 21... Raster data generation section, 22... Reception buffer, 26... Bit string enlargement circuit, 27... Bit string reduction circuit, 28... Paper size data generation section, 29.
・Reduced controller. Applicant's representative Patent attorney Atsushi Tsuboi Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Official Black [n Ming Xiong 1, 'i ('l Indication 15 Application No. 15 Showa 61-240780 2, Title of Invention Color Image Recording Method 3, Relationship with Person Who Makes Amendment Case Patent Applicant (037) J Limbus Kogaku Kogyo Co., Ltd. 4, Agent Kasumiga l! 13-7-2 UBr Building, Chiyoda-ku, Tokyo
100 Telephone 03 (502) 3181 (main representative) 6
, Subject of amendment: Ming #1 full text 7, Contents of amendment: Engraving of the Ming #1 document originally attached to the application, No. 1

Claims (1)

[Claims] Raster data is received and recorded on a recording paper by a line recording head, and while the recording paper and the line recording head are relatively moved in a direction orthogonal to the line recording direction, the raster data is recorded on the same recording paper. In a color image recording method in which images of different colors are superimposed to form a record, correction dots are added discretely to the raster data, and the correction is performed according to information on changes in the width of the recording paper during recording. A color image recording method characterized by recording while increasing and decreasing dots.