JP2000141768A - Image-recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct a density at a low cost without lowering a process speed by reading an original by every predetermined record unit by an equal recording element among a plurality of recording elements and correcting image data in conformity with a characteristic of the recording element for every read unit. SOLUTION: Pixels of an image read sensor 30 are arranged in a direction perpendicular to an arrangement direction of discharge openings of a printing head 60. In order to read an original, the image read sensor 30 is let to scan the original and read the original in units of one lines. Since the pixels of the read sensor 30 are arranged perpendicularly to the arrangement direction of discharge openings, all image data of one line read by the image read sensor 30 are printed by an equal discharge opening. Image data of one line of the read sensor 30 can be corrected at one time in an equal process method. A print irregularity can be eliminated without using a counter or the like circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus, and more particularly, to an apparatus for performing recording with a print head having a plurality of recording elements.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus such as a copying machine, an original to be reproduced is read by an image reading sensor, converted into signalized image data, and an image is formed on a recording medium based on the image data. Is playing the original.

Incidentally, a plurality of recording elements in a recording head of an image recording apparatus may cause variations in recording characteristics of the respective recording elements due to repeated use or the like. For example, in an ink jet type image recording apparatus, there is a case where a difference occurs in an ink discharge amount depending on a discharge port, and density unevenness in each discharge port occurs in a pixel to be printed due to the difference.

Various methods have been conventionally used for such density unevenness, but mainly the following two methods have been generally used.

First, as a first method, multi-pass printing for printing an image for one band, which is an area recordable by operation of a recording head, by a plurality of scans is performed.

First, before describing a method of printing a plurality of passes, a method of printing a single pass will be described for comparison. As shown in FIG. 29, the carriage 60 is
Is moved from the left end in the direction indicated by arrow A, and printing is performed by discharging ink droplets from each print head during this movement. When the carriage 60 moves to the right end of the sheet 15, the carriage 60 is returned to the left end, and
Is moved in the direction indicated by the arrow B by the width of the print head (the width indicated by the arrow C). Therefore, focusing on one print area, the area printed by one scan is the entire area as shown in FIG. That is, since each print area on the paper 15 is printed by one scan, the variation in the ejection characteristics for each ejection port is directly reflected in the print area, and density unevenness may appear remarkably.

[0007] As an example of the multi-pass printing for this,
Two-pass printing will be described. As shown in FIG. 31, the lower half area of the print heads 61, 62, 63, and 64 is an F area, and the upper half area is an R area. First, the carriage 6
0 is moved in the direction indicated by arrow A. When the carriage 60 is moved from the left end of the paper 15 in this manner, printing is performed by ejecting ink droplets from the F regions of the print heads 61, 62, 63, 64 according to print data. When the carriage 60 moves to the right end of the sheet 15, the sheet 15 moves in the direction indicated by the arrow B by half the width of the print head (the width indicated by C / 2 in the figure), and the carriage 60 moves to the left end of the sheet 15. return. The carriage 60 is moved to the right end of the sheet 15 again to perform printing. At this time, a portion printed in the F area in the previous scan is printed in the R area, and a new area of the paper 15 is printed in the F area. Therefore, as shown in FIG. 32, for example, pixels of one line are printed by different ejection openings, so that it is possible to reduce the occurrence of density unevenness due to variation in each ejection opening.

The printing method for printing the same portion of the recording medium N times is called an N-pass printing method.

However, in the above-described multi-pass printing method, the same place on a sheet is scanned a plurality of times and printing is performed. Therefore, there is a problem that it takes more time than one-pass printing.

Next, in a second method, corresponding to the discharge port,
Head shading (hereinafter, HS) that corrects image data based on density data read by a reading sensor
This method does not require a long time for the printing operation itself as in the first method described above.

[0011] Head shading is performed as follows.

First, as shown in FIG. 33, a reading sensor 70 in which read pixels are arranged vertically in the direction indicated by arrow A is scanned in the direction indicated by arrow A. The area read by the reading sensor 70 in one scan is defined as one band. When an image for one band is read, the reading sensor 70 is moved in the direction indicated by the arrow B by the arrangement width of the read pixels, and the next one band is read.

On the other hand, for printing based on the read data, the above-described one-pass printing is performed as shown in FIG.
That is, the carriage 60 is scanned in the direction indicated by the arrow C on the sheet 15 and printing is performed with the width of the print head as one unit. When printing for one band is completed, the paper 15 is moved by one band in the direction indicated by arrow D, and the next printing is performed in the same manner.

As shown in FIG. 35, the relationship between the pixels read by the reading sensor 70 and the ejection openings in the print head 60 is such that the image data read by the pixel G1, which is the head of the reading sensor 70, is Printing is performed at the discharge port N1. Similarly, the pixels G2,. . , G8 read out from the corresponding discharge ports N2,. . , N8. Then, head shading is performed on the image data read by the reading sensor 70, that is, density correction is performed on the image data for each discharge port.

FIG. 36 is a block diagram showing a configuration for this head shading.

The counter 71 indicates which pixel of the image reading sensor 70 the image signal corresponds to. That is, a reset signal is input at the timing when the reading sensor 70 starts scanning for one band, and the counter 71 is cleared. Then, each time the image reading sensor 70 outputs read data of one pixel from the first pixel G1, one count value is added. The counter 71 is connected to the address bus (AB) of the RAM 72,
Is sent to the RAM 72.

The RAM 72 stores discharge characteristics for each discharge port. The area corresponding to the address bus 0 is called the characteristic of the discharge port N1, and the area corresponding to the address bus 1 is called the characteristic of the discharge port N2. As shown in FIG. The characteristics of each ejection port are stored in the RAM 72 as follows. That is, the ejection characteristics stored in a predetermined ROM or the like of the print head are read out and written in the RAM 72, or a predetermined pattern is printed in advance by a printer, and the printing result is written in the RAM 72 based on the read density. It is possible by doing.

The RAM 72 outputs the characteristics of the ejection port stored at the address corresponding to the input count value to the data bus (DB). Output port characteristics are ROM
73 is input. The ROM 73 stores a correction table on how to correct the image data according to the characteristics of the ejection port.

FIGS. 37 to 39 show examples of correction tables. The correction table (1) shown in FIG. 37 outputs the value of the input image signal as it is. FIG.
In the correction table (2) shown in (1), a value larger than the value of the input image signal is output as a correction value. In the correction table (3) shown in FIG. 39, a value smaller than the value of the input image signal is output as a correction value. If the correction value is higher than the input image signal, the print density becomes higher, and if the correction value is lower, the print density becomes lower.

The upper address bus of the ROM 73 has RA
The data bus of M72 is connected, and the above-described characteristics of the ejection port are input. As a result, a correction table corresponding to this characteristic is selected. The image signal, that is, the image data, connected to the lower address bus of the ROM 73 is corrected by the correction table selected as described above. As described above, the image data corrected for each ejection port is output from the ROM 73.

FIG. 40 shows the read pixels of the image reading sensor 70 described above, the correction values of the correction table, and the corresponding relationships among the respective ejection openings of the print head. That is, since the image data read by the pixel G1 positioned at the head of the reading sensor 70 is printed by the ejection port N1, the correction table (3) shown in FIG. 39 is selected from the characteristics of the ejection port N1. Then, in the ROM 73, the image data read by the pixel G1 is converted by the correction table (3), and the correction value H1 is output as the image data of the discharge port N1.

By such density correction by head shading, an image with less density unevenness can be formed even in one-pass printing.

[0023]

However, the conventional head shading has the following problems.

That is, a counter 7 for associating a correction table for each ejection port with a control LSI of the image forming apparatus.
It is necessary to incorporate a circuit such as 1 and there is a problem that this circuit increases the cost.

An object of the present invention is to provide an image recording apparatus which performs low-cost density correction without lowering the processing speed with respect to image density correction.

[0026]

For this purpose, an image recording apparatus according to the present invention comprises an image reading means for reading an original, and a recording apparatus having a plurality of recording elements based on image data of the original read by the image reading means. In an image recording apparatus that performs recording with a head, an image reading unit reads a document for each predetermined unit recorded by the same recording element among the plurality of recording elements, and for each read unit, the image data is recorded as a recording element. It is characterized in that a correction means for performing a correction according to the characteristics is provided.

An image reading means for reading an original, an image processing means for processing image data read by the image reading means, and the image data processed by the image processing means are recorded by a plurality of recording elements. In an image recording apparatus comprising a recording unit, all the image data processed by the image processing unit in one cycle are recorded by the same recording element, and the image data corresponds to the image data before being input to the image processing unit. The recording elements are detected, and correction data for performing correction in accordance with the characteristics of the corresponding recording elements are selected from the correction data provided for each characteristic of the recording elements, and are combined with the image processing data of the image processing means. Wherein the image processing means performs image processing and correction simultaneously by processing the image data with the image processing data. Than it is.

According to the above-described image recording apparatus, since the correction according to the characteristics of the recording element corresponding to the image data read by the image reading means is performed, it is possible to prevent the printing unevenness of each recording element. .

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image recording apparatus according to the present invention will be described.
This will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of the image recording apparatus.

The image recording apparatus 1 has a configuration in which a document to be reproduced is read by an image reading unit 2, the read image data is processed by an image processing unit, and the image is printed by an image printing unit 3.

First, in the image reading section 2, the original 4 to be reproduced is placed on the original platen 22, and the pressure plate 21 and the original platen 2
It is fixed so that it does not move with 2. Original illumination lamp 24
Irradiates the document 4 and the white plate 23. The reflected light is reflected by a reflecting mirror 25, 26, 27 to a lens 28.
Pass through. The light passing through the lens 28 is guided to an image reading sensor (hereinafter, also referred to as “CCD”) 30,
In the CD 30, an image is read.

The original illumination lamp 24 includes a fluorescent lamp,
A halogen lamp, a xenon lamp, an LED array, or the like having a shape in which a light emitting portion is linear is used. The original illumination lamp 24 and the reflection mirrors 25, 26, and 27 are moved by a driving unit (not shown) in the direction indicated by the arrow P to irradiate the entire surface of the original with light.
A series of operations of returning to the initial position is repeated.

The read image data is processed by the image processing unit into a form suitable for printing, and sent to the image printing unit 3.
The details of the image processing will be described later.

The image printing unit 3 includes a cassette 12 containing a recording medium (hereinafter, referred to as “paper”) 15 such as paper.
The paper 15 stored in the cassette 12 is pulled out of the cassette 12 by rotating the paper feed roller 13. The paper 15 pulled out from the cassette 12 passes over the paper transport guide plate 14, moves by the rotation of the transport rollers 16 and 17, passes over the paper transport guide plate 19,
The sheet is conveyed to the sheet discharge tray 20 by the rotation of the sheet discharge roller 18.

From the print head 5 provided between the transport rollers 16 and 17, cyan (hereinafter also referred to as C), magenta (hereinafter also referred to as M), and yellow (hereinafter Y)
), Black (hereinafter also referred to as K) ink droplets, and the ink droplets adhere to the paper 15 to generate dots, whereby an image is formed.

In the image recording apparatus having such a configuration,
How the image data read by the image reading unit 2 is processed by the image processing unit will be described below.

As shown in the image processing block diagram of FIG.
The image data of the light focused on the lens 28 is
By 30, it is converted into an electric signal. The image data converted into the electric signal is input to the analog signal processing unit 31. The analog signal processing unit 31 amplifies the input image data so as to conform to the next input dynamic range of the A / D converter 32. Note that the analog signal processing unit 31
Is a circuit using multiple OP amplifiers or a dedicated IC
Is used to select an arbitrary amplification width. The A / D converter 32 converts the input image data, which is an analog signal, into a digital signal and outputs the digital signal.

The digitally converted image data is corrected by the shading correction processing unit 33 for unevenness in the light amount distribution of the original illumination lamp 24 and variations in image data due to the difference in sensitivity between the read pixels of the CCD 30. The image data that has been subjected to shading correction is converted into an image in a color space of red (hereinafter also referred to as R), green (hereinafter also referred to as G), and blue (hereinafter also referred to as B) of the CCD 30 by the input masking processing unit 34. To image data. The image information converted into the color standard color space passes through the selector 48 and is sent to the black character detection processing unit 35.
The selector 48 selects the image data from the input masking processing unit 34 or the image data from the CPU processing unit 45. The black character detection processing unit 35 determines whether or not there is black character information in the image data. Black character signal information is added to the image data determined to be black characters. The image data for which the black character has been detected is then subjected to processing for enhancing the edge portion of the image and smoothing the gradation expression in the filter processing section 36. The image data that has been subjected to such processing in the filter processing unit 36 is then processed by the scaling processing unit 3.
In step 7, a process for enlarging or reducing the target magnification is performed. The scaled image data is supplied to a LOG conversion processing unit 3
8 converts the R, G, and B luminance signals into C, M, and Y density signals.

The image data converted to the density signal is converted by the output masking / UCR processing unit 39 from color standard color space to image data in a color space in consideration of the printing characteristics of the image printing unit 3. That is, the signals of C, M, Y are converted into the signals of C, M, Y, K.

Next, the image data converted into the C, M, Y, and K signals is converted by the gamma conversion processing section 40 into a density suitable for image formation. The ADD-ON processing section 41 performs processing for embedding predetermined information in the image data converted to the target density.

The ADD-ON processed image data is subjected to necessary processing by a binarization / pallet processing unit 42. For example, in the binarization mode, image data composed of an 8-bit multi-level signal is converted into a 1-bit binary signal. In the pallet mode, image data composed of multi-valued signals of 8 bits in each area is converted into a signal corresponding to a predetermined pattern signal of 4 bits (16 patterns) in 2 × 4 area units. Of the image data subjected to the binarization / pallet processing, for a portion determined as a black character by the black character detection processing unit 35, the black character conversion processing unit 43 converts the C, M, Y image signals into K signals. Processing is performed. However, in the pallet mode, the black character conversion processing is not executed. The output of the black character conversion processing unit 43 is input to the CPU processing unit 45.

The image data input to the CPU processing section 45 is temporarily stored in a memory in the CPU, and then sent to a required processing block. For example, the black character conversion processing unit 4
The image data input from 3 is the image printing unit 3 or
The data is sent to the computer 47 connected to the CPU processing unit 45. The image data from the computer 47 is sent to the image printing unit 3 or the selector 48. As an input signal of the image printing unit 3, binary bit data or pallet data is received.

The computer 47 is connected to the image recording apparatus 1 of the present invention via an interface connector 46. The image forming apparatus 1 has a function of sending image information of the document 4 placed on the document table to the computer 47 and printing the image data sent from the computer 47 by the image printing unit 3. It goes without saying that the image recording apparatus 1 operates even when the computer 47 is not connected.

Next, the flow of image data in four modes related to image processing will be described.

In the first mode, the original 4 placed on the original platen
In this mode, and sends image information of the document to the computer 47. The flow of the image signal is indicated by an arrow in the image processing block diagram of FIG. However, the black character detection processing unit 35, the filter processing unit 36, the scaling processing unit 37, the LO
G conversion processing unit 38, output masking / UCR processing unit 3
9, the γ conversion processing unit 40, the ADD-ON processing unit 41, the binarization / palletization processing unit 42, and the black character conversion processing unit 43 may not require processing. Processing can be passed through the internal circuit.

The second mode is a mode in which image data created by the computer 47 is printed by the printer 44. The flow of image data is indicated by arrows in the image processing block diagram of FIG. The document created by the user of the computer 47 is converted into binary data or pallet data by driver software of the computer 47. The image data converted into binary data or pallet data is transferred from the computer 47 to the image printing unit 3 via the interface connector 46 and the CPU processing unit 45 and printed.

In the third mode, the original 4 placed on the platen
Is a mode in which the read image data is read by the image printing unit 3. The flow of image data is indicated by arrows in the image processing block diagram of FIG.

The fourth mode is a mode in which image data created by the computer 47 is printed by the print 44. The flow of image data is indicated by arrows in the image processing block diagram of FIG. That is, the information of the document created by the computer 47 is sent to the CPU control unit 45,
A black character detection processing unit 35, a filter processing unit 36, a scaling processing unit 37, a LOG conversion processing unit 38,
Output masking / UCR processing unit 39, γ conversion processing unit 4
0, after performing necessary processing in the ADD-ON processing section 41, the binarization / palletization processing section 42, the black character conversion processing section 43, and the CPU processing section 45, sent to the image printing section 3 and printed. You. The printing result is the same as that of the second mode. The difference from the second mode is that the original created by the user of the computer 47 is converted into binary data or pallet data by the driver software of the computer 47. The part to be converted into data is implemented by a hardware circuit. As a result, the time corresponding to the processing time of the driver software of the computer 47 can be reduced.

In consideration of the total printing time of the second mode and the fourth mode, in the second mode, although the processing time of the driver of the computer 47 is required, the amount of data transferred from the computer 47 to the CPU 45 is small. Become. In the fourth mode, the processing time of the driver of the computer 47 is reduced, but the CPU 47
The amount of data transferred to the processing unit 45 increases. Therefore, depending on the state of the image data created by the computer 47, there are cases where the printing time is shorter in the second mode and in some cases the printing time is shorter in the fourth mode. Therefore, an appropriate mode is selected as needed.

Next, the configuration of the CPU processing section 45 will be described.

As shown in FIG. 7, the CPU control unit 45 includes a CPU 50, a ROM 51, a RAM 52, an AS
It comprises an IC 53 and an operation unit 54.

The operation section 54 is connected to the CPU 50.
The operation unit 54 includes a liquid crystal display unit 55 and a key SW 56. Whether or not the key SW 56 is pressed is always detected by the CPU 50. When the key SW 56 is pressed, necessary processing corresponding to the pressed key is performed.
Further, on the liquid crystal display unit 55, the operation state of the apparatus, the name of the key SW 56, and the like are displayed based on information from the CPU 50.

The ROM 51 stores a program for controlling the operation of the CPU 50, image processing parameters, and the like.

The RAM 52 has a function of temporarily storing data of the CPU 50 and image data.

The ASIC 53 converts the image data from the black character conversion processing unit 43 and the CPU 50 into data in a format required for the image printing unit 3 and the computer 47 and sends the data, and transmits the image data from the computer 47 to the CPU 50 and the selector 48. The data is converted into a suitable format and sent.

Next, the flow of image processing in the CPU 50 will be described.

First, the printing mode is selected as shown in the flowchart of FIG.

That is, when the input value of the print mode from the operation unit 54 to the CPU 50 is 1 (step 1),
The print mode selects scan mode processing (step 8).

When the input value of the print mode from the operation unit 54 to the CPU 50 is 2 (step 2), the print mode selects the print 1 mode process (step 7).

If the input value of the print mode from the operation unit 54 to the CPU 50 is 3 (step 3), the print mode selects the copy mode processing (step 6). If the input value of the print mode from the operation unit 54 to the CPU 50 is a value other than 1, 2, and 3, the print mode selects the print 2 mode process (step 4).

Next, the flow of processing in each mode will be described.

First, in the scan mode processing, as shown in FIG. 9, the CPU 50 reads the data sent from the black character conversion processing section 43 (step 1). Next, the read data is temporarily stored in the RAM 52 (step 2). Next, it is determined whether the computer is ready to receive the data. If not, the process returns to step 1 and the reading operation is performed again. If the computer is ready to receive the data, it transfers the data stored in RAM 52 to ASIC 53 (step 4). Next, data is transferred from the ASIC 53 to the computer 47 via the interface connector 46 (step 5). Here, it is confirmed whether or not all the data necessary for reproducing the document 4 has been transferred to the computer, and if the transfer of all the data has not been completed, the processing operation from step 1 is repeated again (step 6). A series of processing ends when all the data has been transferred (step 7).

Next, in the print 1 mode process, as shown in FIG. 10, first, when print data such as a document created by the user of the computer 47 is transferred to the ASIC 53 (step 1), the CPU 50 sends the print data from the ASIC 53 to the print data. Is read (step 2). Next, the print data is temporarily stored in the RAM 52 (step 3).
Then, it checks whether the image printing unit 3 can print,
If the printing preparation is not completed, the process continues until the printing preparation is completed (step 4). When the printing preparation of the image printing unit 3 is completed, the print data of the RAM 52 is transferred to the ASIC 53.
(Step 5). The print data transferred to the ASIC 53 is then transferred to the image printing unit 3 (Step 6). It is confirmed whether or not all the data necessary for printing by the image printing unit 3 has been transferred (step 7). If the transfer of all data has not been completed, the processing operation from step 1 is repeated again. When all the data has been transferred, the operation is completed (step 8).

Next, in the copy mode processing, as shown in FIG. 11, first, the CPU 50 reads the image data sent from the black character conversion processing section 43 (step 1). next,
The read image data is temporarily stored in the RAM 52 (step 2). Next, it is confirmed whether or not all the image data necessary for printing by the image printing unit 3 are available (step 3). If the image data is not available, the processing from step 1 is repeated. When all the image data has been collected, it is confirmed whether or not the image printing unit 3 is in a printable state (step 4). If the preparation for printing is not completed, the user keeps waiting until the preparation is completed. When the printing preparation of the image printing unit 3 is completed, the image data stored in the RAM 52 is transferred to the ASIC 53 (Step 5). Next, ASI
The image data transferred to C53 is sent to the image printing unit 3 (step 6). It is confirmed whether or not all the image data has been transferred to the image printing unit 3 (step 7). If the transfer of all data has not been completed, the processing operation from step 1 is repeated. When the transfer is completed, the process ends (step 8).

Next, the print 2 mode process will be described.
As shown in FIG. 12, first, print data such as a document created by the user of the computer 47 is transferred to the ASIC 53 (step 1).
The print data is read from (step 2). Next, CP
U50 temporarily stores the read print data in RAM 52 (step 3). Next, it is confirmed whether the data necessary for printing of the image printing unit 3 is arranged in the print data (step 4). If the data necessary for printing is not arranged, the process returns to step 1 and the processing from step 1 is repeated. repeat. When the data necessary for printing is sufficient, the CPU 5
0 sends the print data of the RAM 52 to the selector 48 (step 5). Next, the selector 48 selects the input terminal B, sends the print data sent from the CPU 50 to the black character processing unit 35, and performs necessary processing on the print data in the black character processing unit 43 (step 6). . Black character processing unit 4
The print data processed in step 3 is read again by the CPU 50 and stored in the RAM 52 (step 7). Next, the CPU 50 checks whether or not the image printing unit 3 can print (step 8). If the printing preparation has not been completed, the apparatus keeps waiting until the preparation is completed. Image printing unit 3
Is ready for printing, the CPU 50 transfers the print data stored in the RAM 52 to the ASIC 53 (step 9). Next, the print data of the ASIC 53 is transferred to the image printing unit 3 (Step 10). It is confirmed whether or not all the data has been transferred (step 11). If the transfer of all the data has not been completed, the processing from step 1 is repeated again. When all the data has been transferred, the process ends (step 12).

Next, the structure of the print head used in the image recording apparatus 1 will be described.

The print head is composed of a plurality of discharge ports, and the structure near each discharge port is as shown in FIG. That is, the silicon wafer 10 in which the heater 100 as the heating element and the driving circuit (not shown) are integrated.
1, a space sandwiched between the orifice plate 104 and the wall member 109 is filled with the ink 102 for image formation. A portion of the orifice plate 104 corresponding to the upper portion of the heater 100 serves as a discharge port 105, from which ink is discharged.

Next, how the ink is ejected will be described.
First, as shown in FIG. 14, the heater 100 generates heat in accordance with a drive signal given from a drive circuit. Heater 10
When 0 generates heat, bubbles 103 are generated around the heater 100, and the ink 102 is pressed by the pressure generated by the bubbles 103 and rises toward the discharge port 105. Next, FIG.
As shown in FIG.
3 becomes large, and the ink 102 near the ejection port 105 is extruded as an ink droplet 106. Next, as shown in FIG. 16, the ejected ink droplet 106 flies toward a target position on the recording medium. When the heater 100 generates heat for a predetermined time, the heater 100 stops generating heat. When the heating from the heater 100 is stopped, the bubble 103
Decreases rapidly, completely disappears, and returns to the state of FIG. As described above, by repeatedly generating and cooling the heater 100, the ink droplet 106 is ejected. This method is called the bubble jet method,
The ink ejection method is not limited to this method,
Other methods such as a piezo method may be used.

The discharge ports 105 are arranged at regular intervals as shown in FIG. Then, the ink stored in the ink tank 107 is filled from the ink supply port 113 to the vicinity of each discharge port 105 through the ink passage 108 as shown by an arrow. FIG.
FIG. 5 is a view of the print head viewed from the ejection port 105 side. As described above, the three discharge ports 105 are arranged in two rows, and the ink passage 108 is formed in the center.

Next, a method of reading an image by the image reading sensor 30 and a method of printing an image will be described. First, as shown in FIG. 19, the method of reading a document is such that the arrangement direction of the pixels of the image reading sensor 30 is perpendicular to the arrangement direction of the ejection openings of the print head 60. Image reading sensor 3
0 is scanned with respect to the document 4 in the direction indicated by the arrow E,
Reads one line at a time.

In the printing method, as shown in FIG. 20, the carriage 60 is scanned in the direction indicated by the arrow C on the sheet 15 and
Prints with the width of the print head. When printing is performed from the left end to the right end of the sheet, that is, when an image for one band is printed, the sheet 15 is moved by the width of one band in the direction shown by the arrow D, and printing is performed again by the same method.

Since the original reading method and the printing method are as described above, the correspondence between the read image and each ejection port of the print head is as follows. As shown in FIG. 21, all the pixels (G1,..., G8) read by the reading sensor 30 on the first line are printed with the print head arrangement at the head ejection port N1. Also, as shown in FIG. 22, the pixels (G1,..., G8) read by the reading sensor 30 in the next one line.
Means that the arrangement of the print heads corresponds to the second ejection port N2. In this manner, since the pixels of the reading sensor 30 are arranged vertically in the arrangement direction of the ejection openings, all the image data of one line read by the image reading sensor 30 is printed by the same ejection opening. Therefore, as shown in FIG. 23, all the image data of the pixels (G1,..., G8) on the first line are subjected to HS correction in consideration of the characteristics of the ejection port N1. Further, since all the image data of the second line is printed at the ejection port N2, as shown in FIG. 24, HS correction is performed in consideration of the characteristics of the ejection port N2. Therefore, as shown in the block diagram of the conventional head shading shown in FIG. 36, a counter 7 for discriminating which ejection port the input image data corresponds to for each pixel.
1 is no longer needed. That is, image data for one line of the reading sensor 30 can be collectively processed by the same processing method.

By the way, as shown in FIG. 25, the image reading sensor 30 does not always output the image data of each line continuously, but outputs the image data of the first line and waits for a fixed time interval. , The image data of the second line is output. In accordance with such an output pattern, a VE signal is output which is ON while the first line of image data is being output, and is OFF until the next second line of image data is output. Sometimes added. Therefore, the present invention uses this VE signal to perform head shading processing in the following procedure.

The order of the lines read by the image reading sensor 30 is referred to as “line number”.

First, the HS shown in FIG. 37, FIG. 38, and FIG.
The correction table is stored in the ROM 51 in the CPU control unit 45. The characteristics of each discharge port are also determined by the CPU control unit 4.
5 is stored in the RAM 52.

As shown in the flow chart of FIG. 26, first, the line of the image data input from the reading sensor 30 to the image processing unit is detected (step 1). This detection is performed as follows.

That is, as shown in FIG.
0 is input to the interrupt terminal INT of the
Detected at the falling edge of the signal. Introduction RAM
The information of the line counter stored in 52 is read, and the value obtained by adding +1 to the read data is set as the line number of the next input image data. Here, the line counter is cleared immediately before the reading of the document is started, and VE is cleared.
It is incremented by one every time the signal rises, that is, every time an interrupt to the INT of the CPU 50 occurs.

Specifically, before the image data of the first line is output, the value of the line counter is "0", so that the CPU 50 increments the value of the line counter by "0" and adds the line number to "0". Let it be "1". That is, the image data output from the reading sensor 30 is detected as the data of the first line. When the VE signal rises (the point indicated by the arrow in FIG. 25), the value of the line counter becomes “1”.
Becomes Next, when the VE signal falls (point indicated by an arrow in FIG. 25), the CPU 50 increments the value of the line counter by “1” and detects that the next output from the reading sensor 70 is the second line. And so on.

When the CPU 50 detects the number of the line of the image data to be output next from the reading sensor 70 by such means, the CPU 50 detects from which line the next printing is to be performed by using this line number. (Step 2). For example, if it is detected in step 1 that the next image data is for the first line, it can be detected that printing is performed at the discharge port N1.

When it is detected which discharge port is to be used for printing,
The CPU 50 reads the print characteristic data of the discharge port from the RAM 52 (Step 3).

Next, based on the read printing characteristic data, HS correction table data corresponding to the printing characteristics is read from the ROM 51 (step 4).

Next, the gamma conversion table data suitable for the user setting is read out from the gamma conversion table shown in FIG. 28 from the ROM 51, and combined with the previously read HS correction table data (step 5).

Next, the synthesized γ conversion table is converted to a γ
0 is written (step 6), and the process ends (step 7).

More specifically, the HS processing is performed at the point where the VE signal of the first line falls, and the next input 2
A γ conversion table in which HS correction and γ conversion suitable for the image data of the line are configured is written in the γ conversion unit 40. This process is performed during the idle time after the input of the image data of the first line is completed until the image data of the second line is input. Therefore, when the image data of the second line is input to the image processing unit, the γ conversion unit 40 has been rewritten, so that when the image data is processed by the γ conversion unit 40, head shading is performed at the same time. . By using such a method, a circuit such as the counter 71 required for the conventional head shooting processing is not required.

Furthermore, in the above embodiment, the HS correction table is combined with the γ conversion table, and the HS correction is also performed by the γ conversion section 40. However, the HS correction table is combined with the conversion table of the LOG conversion section 38, and the LOG conversion section 38 is combined. May be performed.

The HS correction table is shown in FIGS.
8, the description has been given based on the three patterns shown in FIG. 39. However, the present invention is not limited to these, and other patterns may be used.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for discharging ink, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

The configuration of the recording head is not limited to the combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned specifications. U.S. Pat. No. 4,558,333 and U.S. Pat.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

In addition, even in the case of the serial type as described above, a recording head fixed to the apparatus main body, or an electric connection with the apparatus main body or ink from the apparatus main body by being mounted on the apparatus main body. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is provided integrally with the recording head itself is used.

It is preferable to add a recording head ejection recovery unit, a preliminary auxiliary unit, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

Further, the types and the number of the recording heads to be mounted are, for example, not only those provided for one color ink but also plural inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, it is also possible to adopt a form in which the sheet is opposed to the electrothermal converter in a state where it is held as a liquid or solid substance in the concave portion or through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, the form of the ink jet recording apparatus of the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also for a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0097]

As described above, by using the image recording apparatus of the present invention, head shooting processing can be performed without using a circuit such as a counter. Therefore, the printing unevenness can be eliminated without increasing the cost, and the printing quality can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus of the present invention.

FIG. 2 is an image processing block diagram.

FIG. 3 is an image processing block diagram in a first mode.

FIG. 4 is an image processing block diagram in a second mode.

FIG. 5 is an image processing block diagram in a third mode.

FIG. 6 is an image processing block diagram in a fourth mode.

FIG. 7 is a configuration diagram of a CPU processing unit.

FIG. 8 is a flowchart of a print mode selection process.

FIG. 9 is a flowchart of a scan mode process.

FIG. 10 is a flowchart of a print 1 mode process.

FIG. 11 is a flowchart of a copy mode process.

FIG. 12 is a flowchart of print 2 mode processing.

FIG. 13 is a cross-sectional view illustrating a configuration of a discharge port.

FIG. 14 is a cross-sectional view illustrating a configuration of a discharge port when bubbles are generated.

FIG. 15 is a cross-sectional view illustrating a configuration of an ejection port at the time of ink ejection.

FIG. 16 is a cross-sectional view illustrating a configuration of a discharge port after discharging ink.

FIG. 17 is a sectional view of a print head.

FIG. 18 is a plan view of a print head.

FIG. 19 is a diagram illustrating a method of reading a document.

FIG. 20 is a diagram illustrating a printing method.

FIG. 21 is a diagram illustrating a relationship between a read pixel and an ejection port.

FIG. 22 is a diagram illustrating a relationship between read pixels and ejection orifices.

FIG. 23 is a diagram illustrating a relationship between a read pixel, a correction value, and an ejection port.

FIG. 24 is a diagram illustrating a relationship between a read pixel, a correction value, and an ejection port.

FIG. 25 is a diagram showing a flow of a VE signal.

FIG. 26 is a flowchart of head shooting correction.

FIG. 27 is a block diagram showing a relationship between a CPU and a VE signal.

FIG. 28 is a graph showing an example of gamma conversion data.

FIG. 29 is a schematic diagram illustrating one-pass printing.

FIG. 30 is a diagram illustrating a result of one-pass printing.

FIG. 31 is a schematic diagram illustrating two-pass printing.

FIG. 32 is a diagram illustrating a result of two-pass printing.

FIG. 33 is a diagram showing a conventional reading method.

FIG. 34 is a diagram illustrating a conventional printing method.

FIG. 35 is a diagram showing a relationship between pixels read by a conventional reading method and ejection ports.

FIG. 36 is a block diagram of a conventional head shooting circuit.

FIG. 37 is a graph showing an example of a head shooting correction table.

FIG. 38 is a graph showing another example of the head shooting correction table.

FIG. 39 is a graph showing another example of the head shooting correction table.

FIG. 40 is a diagram showing a relationship between pixels read by a conventional reading method, correction values, and ejection ports.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image recording device 2 image reading unit 21 pressure plate 22 platen 23 white plate 24 document illumination lamp 25, 26, 27 reflecting mirror 28 lens 3 image printing unit 30 image reading sensor 31 analog signal processing unit 32 A / D converter 33 shading Correction processing unit 34 Input masking processing unit 35 Black character detection processing unit 36 Filter processing unit 37 Scaling processing unit 38 LOG conversion processing unit 39 Output masking / UCR processing unit 40 γ conversion processing unit 41 ADD-ON processing unit 42 Binarization / Palletization processing unit 43 Black character conversion processing unit 45 CPU processing unit 50 CPU 51 ROM 52 RAM 53 ASIC 60 Carriage

Continued on the front page F-term (reference) 2C056 EA06 EB26 EB42 EB58 EB59 EC75 EC76 EC79 FA03 HA58 2C262 AA02 AA24 AB05 AC04 BA16 BB34 BB36 5C074 AA09 AA11 AA12 BB16 DD03 DD09 DD24 DD28 EE04 FF15 GG09 PP18 PP08 PQ23 SS02 TT05 TT06

Claims (12)

[Claims] 1. An image reading device for reading a document, and an image recording apparatus for performing recording by a recording head having a plurality of recording elements based on image data of the document read by the image reading device, wherein the image reading device is A correction unit is provided for reading a document for each predetermined unit recorded by the same recording element among the plurality of recording elements, and for each of the read units, correcting image data according to characteristics of the recording element. Image recording device. 2. The image recording apparatus according to claim 1, wherein the correction unit corrects printing unevenness. 3. Correction data for performing correction in accordance with the characteristics of a recording element in units read by the image reading means,
2. The image recording apparatus according to claim 1, further comprising image processing means for synthesizing image data with image processing data to be processed into data corresponding to a recording element, and performing image processing and correction simultaneously. 4. An image recording apparatus according to claim 3, wherein said image processing means adjusts a print density. 5. The image recording apparatus according to claim 3, wherein said image processing means performs conversion from luminance to density. 6. An image reading means for reading an original, an image processing means for processing image data read by the image reading means, and the image data processed by the image processing means are recorded by a plurality of recording elements. In an image recording apparatus including a recording unit, all image data processed by the image processing unit in one cycle are recorded by the same recording element, and the image data is processed before being input to the image processing unit. The print elements are detected, and correction data for performing correction in accordance with the characteristics of the print elements are selected from the correction data provided for each characteristic of each print element, and are combined with the image processing data of the image processing means. An image processing unit that performs image processing and correction simultaneously by processing image data with the image processing data. Recording apparatus. 7. The image recording apparatus according to claim 6, wherein the correction unit corrects printing unevenness. 8. An image recording apparatus according to claim 6, wherein said image processing means adjusts a print density. 9. An image recording apparatus according to claim 6, wherein said image processing means performs conversion from luminance to density. 10. The image reading means reads an image in a fixed pixel unit, provides a fixed time between a previously read pixel group and a next read pixel group, and sets a corresponding printing element during this time. 10. The image recording apparatus according to claim 6, wherein the image recording apparatus detects and performs a synthesizing process of synthesizing a correction unit corresponding to the characteristic of the recording element with the image processing unit. 11. The image recording apparatus according to claim 10, wherein said image reading means is provided with a pulse signal which is turned on while reading an image, and performs the synthesizing by using a fall of the pulse signal as a signal. apparatus. 12. The recording device according to claim 1, wherein the recording means uses heat energy to generate bubbles in the recording ink, and discharges the recording ink by the pressure of the generated bubbles.
The image recording apparatus according to claim 11.