JP2005271415A - Ink-jet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet recording method which enables double-sided recording by suppressing set-off in printing without a difference in density on right and left pages at the time of viewing a recording result. <P>SOLUTION: Recording densities of right and left pages are made uniform when browsing a recording result while suppressing the lowering of image quality caused by the set-off of ink by making ink reduction volumes of the rear surface of a present recording medium and the front surface of a succeeding recording medium uniform, at the time of double-sided recording. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording apparatus and a recording method, and more particularly to a recording method using a recording head that performs recording by ejecting ink according to an ink jet method.

  In recent years, OA equipment such as personal computers, copying machines, word processors, and the like has become widespread, and a recording apparatus that performs digital image recording by an ink jet method as a kind of image forming (recording) apparatus of these equipment has rapidly developed and spread. ing. In particular, along with the enhancement of the functions of OA devices, the colorization of these devices is progressing, and various color ink jet recording apparatuses have been developed accordingly.

  In general, an ink jet recording apparatus includes a carriage on which a recording head and an ink tank are mounted, a transport mechanism that transports recording paper, and a control circuit that controls these. In such a recording apparatus, ink is ejected while serially scanning a recording head having a plurality of ejection openings for ejecting ink droplets in the direction (main scanning direction) perpendicular to the recording paper conveyance direction (sub-scanning direction). On the other hand, the recording operation is executed by intermittently conveying the recording paper by an amount equal to the recording width of the recording head while ink is not ejected from the recording head. Further, in the case of a recording apparatus capable of color recording, a color image is formed by superimposing ink droplets ejected from a plurality of recording heads.

  As a method for ejecting ink, a heating element (electrothermal energy converter) is provided in the vicinity of the ejection opening, and an electric signal is applied to the heating element to locally heat the ink to cause a pressure change. There are known a method of ejecting ink from an ejection port and a method of ejecting ink by applying a mechanical pressure to ink using a piezoelectric element such as a piezoelectric element.

  This ink jet recording method records characters and figures by ejecting ink as fine droplets from a discharge port onto a recording medium according to a recording signal, and has low noise because it is non-impact. Because it has advantages such as low running costs, easy downsizing, and relatively easy colorization, it can be used in combination with computers and word processors, etc. Are widely used as image forming (recording) means in recording apparatuses such as copying machines, printers, and facsimiles.

  1 and 2 are block diagrams showing schematic configurations of a controller unit and an engine unit of the ink jet recording apparatus, respectively.

  First, the function and schematic operation of the controller unit will be described. The CPU 101 is connected to the host computers 120, 121, 123 via the USB interface 108, the IEEE 1394 interface 109, and the local area network interface 122, and stores a control program, an updatable control program, a processing program, various constant data, and the like. The ROM 105 and the RAM 104 for storing command signals and image information received from the host computer 120 are accessed, and the recording operation is controlled based on the information stored in these memories. The instruction information input from the keys of the operation panel 107 is transmitted to the CPU 101 via the operation panel interface 106, and the LED lighting and LCD display of the operation panel 107 are similarly controlled via the operation panel interface 106 according to commands from the CPU 101. Is done. The HDD 110 has a larger storage capacity than the RAM 104 and is a secondary storage device that stores image data and the like. The image information is converted into dot data of each ink color by the image data processing block 111 and output to the engine (FIG. 2). Similarly, various commands and status information are transmitted and received between the controller and the engine via the image data processing block 111.

  Next, the function and operation outline of the engine unit will be described. The engine unit is connected to a controller (FIG. 1) via a band memory control block 209. The CPU 201 accesses a ROM 203 storing a control program, an updatable control program, a processing program, various constant data, and the like, and a controller (FIG. 1) RAM 202 for storing received command signals and image information. The recording operation is controlled based on the stored information. The carriage 220 is moved by operating the carriage motor 208 via the carriage motor control circuit 207. Further, by operating the paper feed motor 205 via the paper feed motor control circuit 204, the paper transport mechanism 206 such as a transport roller is operated. Further, the CPU 201 can record a desired image on a recording medium by controlling the band memory control block 209 and the recording head control block 211 based on various information stored in the RAM 202 and driving the recording head 212. .

  A power supply circuit (not shown) is supplied with a logic drive voltage Vcc (for example, 3.3 V) for operating the CPU and various control circuits, various motor drive voltages Vm (for example, 24 V), and a heat voltage for driving the recording head. Vh (for example, 12V) is output.

  As a method of binarizing multi-value data to obtain binary data and reproducing a gradation image in a pseudo manner using the binary data, for example, (1) density pattern method, (2) systematic pattern dither And (3) error diffusion method.

  In the density pattern method, one pixel is developed into M × N recording dots (M and N are integers of 1 or more), and gradation expression by binary is performed by area modulation, and dots are recorded per unit area. The area modulation is realized by changing the number (number of ink particles).

  In the pattern dither method, a pattern dither matrix including threshold values configured in a matrix is prepared, and one-to-one pixel comparison between each threshold value and each pixel of input data is performed to determine ON / OFF.

  In the error diffusion method, a diffusion coefficient is assigned to a peripheral pixel for a target pixel, and a quantization error generated in the target pixel is distributed to the peripheral pixels according to the diffusion coefficient. As a result, the density of the entire image is preserved, and a favorable pseudo gradation expression is possible.

  Generally, the color ink jet recording method uses three color inks of cyan (C), magenta (M), and yellow (Y), and further uses four color inks added with black (Bk). Realizes color recording. In such a color ink jet recording apparatus, unlike a monochrome dedicated ink jet recording apparatus that records only characters, various factors such as color development, gradation expression, and uniformity of an image are recorded in recording a color image. It is necessary to consider.

  The quality of the recorded image largely depends on the performance of the recording head unit. The slight differences in the characteristics of each nozzle that occur during the printhead manufacturing process, such as the shape of the printhead discharge ports and the variations in the quality of the electrothermal transducer (discharge heater), are due to the amount and direction of ink discharged. The direction of the image is influenced, and these effects appear as density unevenness in the finally formed recorded image, which causes deterioration in image quality. As a result, there are “white” portions that do not meet the area factor of 100% periodically in the main scanning direction of the recording head, or conversely, the dots overlap abnormally or white streaks occur. Will be. These phenomena are usually perceived as uneven density by the human eye.

  Therefore, a method called a multi-pass recording method has been proposed as a countermeasure against such density unevenness. Here, for the sake of simplicity, a case will be described in which a recording head that performs recording using a single color ink consisting of 8 nozzles is used.

  In the first scan of multi-pass printing, even-numbered row patterns are used, and in the second scan, odd-numbered row patterns are used. In the first scan, print data is thinned using a staggered pattern and a second scan is an inverted staggered pattern. A case where two-pass printing is realized by adopting a fixed mask method for generating pass data according to FIG. The staggered pattern is recorded in the first scan, the paper is fed by half the recording width (4 dot width), and then the inverted staggered pattern is recorded in the second scan to complete the recording. That is, the recording area in units of 4 dots is completed for each scan by alternately performing paper feeding in units of 4 dots and recording in a zigzag / reverse zigzag pattern.

  Next, two-pass printing is realized by adopting a table reference method that generates pass data by thinning out print data using a random mask pattern in which print dots and non-print dots are randomly arranged. The case will be described. 3 is a diagram showing an example of a mask table for each recording scan, table areas A and B are complementary mask tables used in the first pass and the second pass, respectively. The table is 1 bit / dot, 0 indicates a mask target, and 1 indicates a non-mask target. Mask tables A and B are tables each having a size corresponding to 12 pixels in the main scanning direction and 4 pixels in the sub-scanning direction, and are repeatedly developed in each direction and used as mask data. The number of nozzles provided in the recording head is 8, and the number of pixels corresponding to the paper conveyance amount in 2-pass recording is 8/2 = 4, which matches the sub-scanning direction sizes of Tables A and B.

  FIG. 4 is a diagram for explaining the state of recording scanning using the mask table shown in FIG. For 8 lines of data corresponding to 8 nozzles, A and B are applied as mask patterns every 4 lines. In each recording scan, image data masking (replaces recording dots with non-recording dots) is executed using the stored mask table to generate and output pass data. Specifically, by taking the logical product of the image data and the mask data, if the mask data is 1, the image data is output as it is, and if the mask data is 0, the image data is This is realized by replacing with 0. All image areas are always masked in the order of A and B by two scans to generate print data. Here, the mask OFF (1) ratios of A and B are equally about 50%.

  Similarly to the table reference type two-pass recording, an example of the table reference type four-pass recording is shown below. FIG. 5 is a diagram showing an example of a mask table for each printing scan. The table areas A, B, C, and D are complementary to each other used in the first pass, the second pass, the third pass, and the fourth pass. It is a mask table. The table is 1 bit / dot, 0 indicates a mask target, and 1 indicates a non-mask target. The mask tables A, B, C, and D are tables each having a size corresponding to 12 pixels in the main scanning direction * 2 pixels in the sub scanning direction, and are repeatedly developed in each direction and used as mask data. The number of nozzles provided in the recording head is 8, and the number of pixels corresponding to the paper conveyance amount in 4-pass recording is 8/4 = 2, which matches the sub-scanning direction sizes of the tables A, B, C, and D. .

  FIG. 6 is a diagram for explaining the state of recording scanning using the mask table shown in FIG. For 8 lines of data corresponding to 8 nozzles, A, B, C and D are applied as mask patterns every 2 lines. In each recording scan, image data masking (replaces recording dots with non-recording dots) is executed using the stored mask table to generate and output pass data. Specifically, by taking the logical product of the image data and the mask data, if the mask data is 1, the image data is output as it is, and if the mask data is 0, the image data is This is realized by replacing with 0. All image areas are always masked in the order of A, B, C, and D by four scans to generate print data. Here, the mask OFF (1) ratios of A, B, C, and D are equally about 25% each.

  Thus, by recording one line using two different nozzles, it is possible to form a high-quality image with suppressed density unevenness. In addition, the multi-pass printing method has the effect of suppressing bleeding (bleeding) by printing while drying the ink, and the print head temperature rise, which causes ejection failure, by reducing the printing dots for each scan. The suppression effect can be achieved at the same time. Although the main scanning direction has been described here, it is possible to further improve the image quality by thinning out and recording continuous dots in the sub-scanning direction. Further, when it is desired to realize image formation in the sub-scanning direction at a resolution higher than the nozzle resolution, the thinning recording in the sub-scanning direction is an essential process.

  As described above, the pass data for each scan is generated by thinning out the print data using a random mask pattern in which print dots and non-print dots are randomly arranged as described above. In addition to the method of generating the data (referred to as the table reference method), the method of generating the pass data by thinning out the recording data using the even / odd column pattern or the zigzag / reverse zigzag pattern (referred to as the fixed mask method) In addition, a method of generating pass data by performing a thinning process while paying attention to recording dots (referred to as a data mask method) or a method using these in combination is known.

  Although this kind of image formation has been devised to achieve high image quality, this method of recording an image by landing ink droplets on the recording medium has the effect of show-through of the image, waviness and curl of the recording medium. It has the property of being easily generated.

  In particular, when double-sided recording is performed in an ink jet recording apparatus, if an image show-through occurs, the image quality of the front and back surfaces may be significantly reduced.

In conventional inkjet recording devices, the recording density is changed during single-sided recording and double-sided recording, and during double-sided recording, the recording density is changed to be lower than that during single-sided recording, or the recording density on the front and back sides is changed. (See, for example, Patent Document 1).
Japanese Patent No. 07-314734

  However, if the recording density for single-sided recording and the recording density for double-sided recording are changed as described above, the image quality in double-sided recording will be uniformly reduced. In addition, when the recording density on the front and back sides is changed, there is a problem that the density differs between the left and right pages when browsing depending on the surface.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide an ink jet recording method for recording an image with little show-through in double-sided recording and no difference in right and left density during browsing.

  In order to solve the above problems, an ink jet recording method according to a first aspect of the present invention comprises the following arrangement.

  An ink jet recording method for performing recording on both sides or one side of the recording medium using a plurality of inks, an ejection port, and a recording head for ejecting ink from the ejection ports to the recording medium, and performing duplex recording on the recording medium Means for designating either a double-sided recording mode or a single-sided recording mode for recording on one side of the recording medium, a recording density detecting means for detecting a recording density per unit area, and a recording for storing a plurality of the recording density detection results When the density storage means, the recording density comparison means for comparing a plurality of recording densities stored in the recording density, and the double-sided recording mode are designated, the recording density in the single-sided recording mode is determined based on the result of the recording density comparison. The selection is made by comparing the recording density with the selection means and the recording density comparison means, which is the same as or lower than the single-sided recording mode. Ink jet recording method and performing recording at a recording density that.

  Furthermore, the ink jet recording method according to the second aspect of the present invention comprises the following arrangement.

  The inkjet recording method according to claim 1, wherein the density comparison is performed on a back surface of a recording medium and a front surface of a next medium.

  Furthermore, the ink jet recording method according to the third aspect of the present invention has the following configuration.

  2. The ink jet recording method according to claim 1, wherein the density determination of the front surface of the first page during double-sided recording and the final page (back surface) during even-numbered page recording is performed by adjusting the recording density on a single surface.

  Furthermore, the ink jet recording method according to the fourth invention of the present invention has the following configuration.

  2. The ink jet recording method according to claim 1, wherein the recording density is lowered by reducing the amount of ink discharged per unit area for recording.

  Furthermore, the ink jet recording method according to the fifth aspect of the present invention comprises the following arrangement.

  5. The ink jet recording method according to claim 1, wherein the ink amount per unit area ejected for recording is applied to the entire surface of the recording medium.

  Furthermore, the ink jet recording method according to the sixth aspect of the present invention comprises the following arrangement.

  5. The ink jet according to claim 1, wherein one surface of the recording medium is divided into a plurality of areas, and an ink amount per unit area ejected for recording is determined for each divided area. Recording method.

  Furthermore, the ink jet recording method according to the seventh aspect of the present invention comprises the following arrangement.

  The inkjet recording method according to claim 1, wherein the recording density is lowered by reducing the number of recording dots formed on the recording medium.

  Furthermore, the ink jet recording method according to the eighth aspect of the present invention comprises the following arrangement.

  8. The ink jet recording method according to claim 1, wherein the energy generation element includes an electrothermal converter that generates thermal energy that causes film boiling in the ink. 9.

  Furthermore, the ink jet recording method according to the ninth aspect of the present invention comprises the following arrangement.

  The image forming system is configured by connecting an image forming engine adopting a method of forming an image by ejecting ink droplets by activating a pressure generating element and forming dots on each pixel. 7. The ink jet recording method according to claim 1.

  As described above, by making the same amount of ink reduction on the back surface and the front surface of the next recording medium at the time of double-sided recording, it is possible to reduce left and right when viewing the recording results while reducing image quality deterioration due to ink show-through. It is possible to make the recording density the same on the page.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 11 is a sectional view showing the configuration of the ink jet recording apparatus according to the present invention.

  Reference numeral 1101 denotes a recording sheet, and the recording sheets 1101 are fed one by one from the uppermost side by a feeding roller 1102. The recording sheet 1101 fed by the feeding roller 1102 is conveyed to the recording position by the conveying roller 1104 through the upper guide and the lower guide 1103. The conveyance roller 1104 pitch-feeds the recording sheet 1101 to the recording position by a predetermined amount. A recording head 1105 serves as a means for recording an ink image on the recording sheet 1101 conveyed by the conveyance roller 1104 at the recording position. It is kept movably mounted on the carriage 1106. Although not shown, the recording head 1105 is provided with a fine ink discharge port, a liquid path, and a part of the liquid path, and includes energy generating means for heating the ink with a heating resistor to discharge the liquid. The carriage 1106 is guided along the guide shaft 1107 and the guide rail 1108, and reciprocates in the direction perpendicular to the drawing by a drive motor and a feed mechanism (not shown). Reference numeral 1109 denotes a platen provided at a recording position facing the recording head 1105, and the recording sheet 1101 is supported from the back side by the platen 1109. The recording sheet 1101 on which the ink image is recorded is guided to the flapper 1111 by the discharge roller 1110. Here, when the double-sided recording mode is selected, the flapper 1111 is switched to the solid line position shown in the figure, and the recording sheet 1101 is conveyed in the conveyance path. It feeds to the lower part of the apparatus along 1112. Then, it is fed into the reversing pocket 1114 by the forward rotation of the forward / reverse roller 1113, and then the direction is reversed by the reverse operation of the forward / reverse roller 1113 and the switching operation of the flapper 1115 from the illustrated solid line position to the broken line position. Is sent back to the transport roller 1114 via the S-shaped transport path 1116 and is again guided onto the platen 1119. Then, the recording sheet 1111 that has been retransmitted by reversal is recorded on the surface opposite to the surface previously recorded by the recording head 1115 and then switched to the position indicated by the broken line in the figure. Guided by flapper 1111, transported along transport path 1117, and sequentially stacked on discharge tray 1118. The recording operation in the case of the double-sided recording mode has been described above. However, in the case of the single-sided recording mode, the recording sheet 1101 is switched to the position indicated by the broken line in FIG. 1101 is guided along the transport path 1117 and immediately discharged onto the discharge tray 1118 and sequentially stacked on the discharge tray 1118.

  FIG. 14 shows the configuration of the recording unit of the ink jet recording apparatus according to the present invention.

  Reference numeral 1105 also shown in FIG. 11 is a recording head, which includes ink tanks filled with four color inks of black (Bk), cyan (Cy), magenta (Mg), and yellow (Ye), respectively. It is composed of a multi-head composed of four corresponding independent heads. Reference numeral 1106 denotes a carriage that supports the recording head 1105 and moves them together with recording. The carriage can move in the X direction using the stay 1107. The carriage 1106 is in a home position position 1401 in the drawing when it is in a standby state such as a non-recording state. Reference numeral 1110 denotes a paper discharge roller that rotates while suppressing the recording sheet 1101 and feeds the recording sheet 1101 in the Y direction as needed. Reference numeral 1104 denotes a conveyance roller. Here, the recording head 701 has 1024 nozzles respectively arranged in the paper feed direction for the four colors Bk, Cy, Mg, and Ye.

  A basic recording operation in the above configuration will be described.

  During standby, the carriage 1105 at the home position 1401 performs recording by ejecting ink onto the recording sheet 1101 according to the recording data from the plurality of nozzles of the recording head 1105 while moving in the X direction in response to a recording start command. When the recording of the recording data to the end of the recording sheet 1101 is completed, the carriage 1106 returns to the original home position position 1401. When the transport roller 1104 rotates in the arrow direction 1402, the transport roller 1104 transports by a predetermined width in the Y direction, and the carriage 1106 again ejects ink while moving in the X direction to start recording. Data recording is realized by repeating such scanning operation and conveyance operation.

  The ink jet recording apparatus of this embodiment converts an interface for exchanging image information and various control information with a host computer or the like, and converts input image information into dot ON / OFF data for each ink color. And a controller (FIG. 1) configured with an image data processing block, and an engine (FIG. 2) for conveying a recording sheet and driving a carriage and controlling the recording head to form an image. ing.

  Next, the image data processing of the image data processing block 111 will be described in detail.

  FIG. 7 shows a schematic block diagram of an image data processing block in the controller. The image data processing block sequentially executes processes such as color conversion and quantization. The input image information is converted into multi-value image data for each ink color, and then quantized using an error diffusion method and a density pattern method to generate dot data for each ink color. The generated dot data is output to the engine.

  The color conversion process will be described. FIG. 8 shows a processing flow of the color conversion block. The color conversion block sequentially executes three processes such as input gamma correction, color space conversion, and output gamma correction. The input gamma correction block performs input gamma correction processing by a table reference method, and outputs 10-bit data of R, G, and B colors obtained by using the input 8-bit data of R, G, and B colors as a table input. The 10-bit data for each of the R, G, and B colors output from the input gamma correction block is supplied to the color space conversion block. The color space conversion block converts the R, G, B data into 10-bit data for each of the K, C, M, and Y ink colors by the tetrahedron interpolation method, and outputs the converted data to the output gamma correction block at the subsequent stage. The output gamma correction block performs output gamma correction processing by a table reference method, and generates and outputs 10-bit data of K, C, M, and Y colors.

  The quantization process will be described. FIG. 9 shows a processing flow of the quantization block. The quantization block sequentially executes two processes, an error diffusion process and a halftone dot expansion process. The error diffusion block performs quantization processing based on the multilevel error diffusion method, and converts the input 10-bit data for each color of K, C, M, and Y into the number of gradations corresponding to the print mode. Specifically, a 9-value process is performed in the “fast mode”, and a 5-value process is performed in the “pretty mode”. In the subsequent halftone dot development block, halftone dot development of a matrix size corresponding to the print mode is executed. Specifically, in the “fast mode”, binary data is developed using a 2 × 4 dot matrix, and in the “clean mode”, binary data is obtained using a 2 × 2 dot matrix. is there.

  Next, the entire recording density control sequence, which is characteristic in the present invention, will be described with reference to FIG.

  When the printer is turned on (S1001), when image data is received from the host computer (S1002), the printer sucks the recording medium. Further, the CPU (101) determines whether the single-sided recording or the double-sided recording is performed from the information of the recording method included in the data inside the printer (S1003). For single-sided recording, image data is input (S1004) and received by the RAM (104) or the HDD (110). In order to convert the image data into data recordable, image data processing (S1005) is performed in the image data processing block (111), and the processed result is recorded in data (S1006). If data recording for one page has been completed (S1007), the recording medium is ejected to the paper tray (S1008), and the recording is completed. In this way, the flow does not perform density reduction.

  In the case of duplex recording, image data is input (S1010) and received by the RAM (104) or the HDD (110). In order to convert the image data into data recordable, image data processing (S1012) is performed and stored in the image data processing block (111) (S1011). The ink ejection amount is counted from the processed data (S1013). If data recording for one page has been completed (S1014), the density reduction amount for that page is calculated from the ink placement amount accumulated for one page (S1015). The ink density reduction amount is a reduction amount that is necessary for keeping the counted ink ejection amount within the preset upper limit value of the ink ejection amount per unit area during double-sided recording. In this embodiment, the unit area is one page. The reduction amount is stored as a density reduction amount A. If the page on which the ink ejection amount is counted is the first page (S1016), the image data processing block (111) uses the data stored in the data storage (S1011) after the image data processing and the density reduction amount A to record data. Image data processing (S1017) is performed for possible data conversion. In this embodiment, as a density reduction method, after the quantization process, a process of thinning out the recording dots (masking the dots) according to the density reduction amount is performed after the number of recording dots. For example, if the density reduction amount is half of the ink placement amount, mask data is generated and data processing is performed so that the number of recording dots is thinned by 50% as shown in FIG. Data recording is performed on the result of the density reduction processing in this way (S1018). When the data recording for one page is completed (S1019), it is determined whether there is a next page (S1020). If there is a next page, the flapper 1111 shown in FIG. 11 is switched to the solid line position, and the recording medium is reversed in the apparatus (S1022) to prepare for recording on the back surface. If there is no next page, the flapper 1111 is switched to the broken line position, and the recording medium is discharged to the paper tray (S1021).

  If the density reduction amount A is calculated (S1015) is not the first page (S1016), it is determined whether it is the back side (S1030). If it is the back side, it is confirmed whether there is image data of the next page (S1031). To do. If there is a next page, it is necessary to compare the calculated back surface data and the density reduction amount of the front surface of the next page, so the density reduction amount A (S1015) is stored as the density reduction amount L (S1032), and the next page is stored. Return to the process. At the front side (S1030), the previous page density reduction amount L (S1032) and the density reduction amount A (S1015) are compared, and the larger density reduction amount is stored as the density reduction amount LR (S1040). And it adapts to the current page (surface). First, image data processing (S1041) is performed in order to convert the data that can be recorded by the image data processing block (111) using the data of the image data storage (S1011) of the previous page (back side) and the density reduction amount LR. The processed result is recorded as data (S1042). If data recording for one page has been completed (S1043), it is determined whether or not the recording is on the front side (S1044). Since the first page is the previous page (back side), the recording medium is reversed in the device (S1045). In preparation, return to S1041. The image data in S1041 is processed by the image data processing block (111) for data conversion so that the image data processing block (111) can record data using the data in the image data storage (S1011) of the current page (front surface) and the density reduction amount LR. (S1041) is performed, and the processed result is recorded as data (S1042). If the data recording for one page has been completed (S1043), it is determined whether or not the recording is on the front surface (S1044). Since the recording is on the front surface, if there is a next page (S1020), the recording medium is reversed in the device ( S1021) Preparing for recording on the back surface. If there is no next page, the recording medium is discharged to the paper tray (S1021). As a method for thinning out the recording dots, it is possible to increase the mask OFF ratio instead of the complementary mask table for the random mask pattern of the multi-pass printing.

  A second embodiment for realizing density reduction during double-sided recording according to the present invention will be described.

  The overall recording density control sequence will be described with reference to FIG.

  The difference from the flowchart of FIG. 10 shown in the first embodiment is in S1311, S1313, and S1315.

  In the first embodiment, recordable data after image data processing is stored (S1011). However, in this embodiment, the input data itself is recorded (S1311).

  Accordingly, the processing contents in S1317 corresponding to S1017 are also different. In step S1317, the gamma reference table used in the output gamma / density correction unit (S803) of the image data processing block 111 is changed so that the gamma value becomes smaller (becomes brighter).

  Further, in S1313 corresponding to S1013 in the first embodiment, the density was reduced by using one page as a unit area in the first embodiment, and thus the ink placement amount was counted (S1013). In order to cope with this case, the recording sheet of the unit area is divided as shown in FIG. 15 (12 divisions in this embodiment), and the ink ejection amount is counted for each AREA. In calculating the density reduction amount in S1315 from the ink placement amount for each AREA, the area where the ink placement amount is the maximum is calculated.

  The present invention is not limited by the operation principle or configuration of the recording head. That is, the recording head is provided with a heating element (electrical / thermal energy conversion element) in the vicinity of the discharge port, and by applying an electric signal to the heating element, the ink is locally heated to cause a pressure change, and the ink is discharged. A thermal system that ejects ink from an ejection port may be used, or a piezoelectric system that ejects ink by applying mechanical pressure to the ink using an electrical / pressure converting means such as a piezoelectric element.

  The form of the ink jet recording apparatus according to the present invention is not limited to an image output apparatus of an information processing apparatus such as a computer or a word processor, but is provided integrally or separately, and a copying apparatus or a communication function combined with a reading apparatus. It may be a facsimile machine having In addition, the image data processing for data recording may be an ink jet recording apparatus that does not have a controller unit and that is executed by software on a computer before being sent to the ink jet printer.

It is a schematic block diagram of the controller part in an inkjet recording device. It is a schematic block diagram of the engine part in an inkjet recording device. It is a figure which shows an example of the mask table for multipass 2 pass data production | generation. It is a figure explaining the mode of multipass printing using the mask table of FIG. An example of a mask table for each scan of the 4-pass printing in the table reference method is shown. It is a figure explaining the mode of the recording scan using a mask table. It is the schematic of the image data processing internal recording part of a controller part. It is the schematic of a color conversion block. It is the schematic of a quantization block. 6 is a flowchart illustrating a recording control operation in the first embodiment of the present invention. It is sectional drawing which shows typically the structure of the inkjet recording device of this invention. It is a figure which shows the example of a mask pattern used for the recording density reduction in 1st Example of this invention. 6 is a flowchart illustrating a recording control operation in the second embodiment of the present invention. It is a figure showing composition of a recording part of an ink jet recording device. FIG. 5 is a diagram illustrating a state in which a unit area is divided into a plurality of areas and an ink ejection amount is counted for each area.

Claims (9)

An ink jet recording method for performing recording on both sides or one side of the recording medium using a plurality of inks, ejection openings, and a recording head that ejects ink from these ejection openings to the recording medium,
Means for designating either a double-sided recording mode for performing double-sided recording on the recording medium or a single-sided recording mode for recording on one side of the recording medium;
A recording density detecting means for detecting a recording density per unit area;
Recording density storage means for storing a plurality of the recording density detection results;
A recording density comparison means for comparing a plurality of recording densities stored in the recording density;
When the double-sided recording mode is designated, based on the result of the recording density comparison, a selection unit that selects a recording density equal to or lower than the recording density in the single-sided recording mode,
An ink jet recording method, wherein recording is performed at the selected recording density for a comparison made by the recording density comparison means.   The inkjet recording method according to claim 1, wherein the density comparison is performed on a back surface of a recording medium and a front surface of a next medium.   2. The ink jet recording according to claim 1, wherein the density determination of the front surface of the first page of the recording medium at the time of duplex recording and the final page (back surface) at the time of even page recording is performed by adjusting the recording density on a single surface. Method.   2. The ink jet recording method according to claim 1, wherein the recording density is lowered by reducing the amount of ink discharged per unit area for recording.   5. The ink jet recording method according to claim 1, wherein the ink amount per unit area ejected for recording is applied to the entire surface of the recording medium.   5. The ink jet according to claim 1, wherein one surface of the recording medium is divided into a plurality of areas, and an ink amount per unit area ejected for recording is determined for each divided area. Recording method.   The inkjet recording method according to claim 1, wherein the recording density is lowered by reducing the number of recording dots formed on the recording medium.   8. The ink jet recording method according to claim 1, wherein the energy generation element includes an electrothermal converter that generates thermal energy that causes film boiling in the ink. 9.   The image forming system is configured by connecting an image forming engine adopting a method of forming an image by ejecting ink droplets by activating a pressure generating element and forming dots in each pixel. 7. The ink jet recording method according to claim 1.

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