JP2006218783A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder on which an operator and a general user operating a printer can reflect his/her intention. <P>SOLUTION: The inkjet recorder is provided with: a determining means to determine whether page recording operation shall be suspended by determining a threshold for a size of a recording image, and also by determining a threshold for the number of recording pixels; an inputting means for making a user set a threshold for determining a threshold for the size of the recording image; and data thinning masks having different thinning rates as thinning masks for a multipath recording method. The recorder compares a threshold prepared in advance as a threshold for the size of the recording image with a threshold set by a user, and when the threshold the user has set is smaller, a determining condition on the number of the recording pixels is ignored, while when the threshold the user has set is larger, the image is formed by using a thinning mask making an image density thin as a thinning mask for making multipath recording to act on through the whole page recording. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a so-called multipass recording type ink jet recording apparatus.

  In recent years, with the progress of office automation and the spread of personal computers and the like, as an apparatus for recording a digital image handled on a personal computer on a recording material, an ink jet recording apparatus using an ink jet recording head has been rapidly used. It is popular. Ink jet recording heads are generally provided with a plurality of liquid discharge ports for discharging a liquid and a plurality of liquid flow channels communicating therewith, in order to discharge liquid from each liquid discharge port in each liquid flow channel. Is provided with a recording element that gives the liquid energy.

  As a method for ejecting liquid in an ink jet recording apparatus, a heating element (electrical / thermal energy converter) is provided as a recording element in the vicinity of the ejection port, and an electric signal is applied to the heating element to locally heat the liquid. There are a method using an electric / thermal energy converter that causes a pressure change and discharges liquid from an outlet, and a method using an electric / mechanical converter such as a piezoelectric element as a recording element. Also known is a configuration in which an electric pressure converting means such as a piezo element is used as a recording element and a liquid is mechanically applied to discharge the liquid.

  In this ink jet recording apparatus, the digital image recording time is shortened and the output image quality is improved. Therefore, as a recording head mounted in an ink jet recording apparatus, a recording head (hereinafter referred to as a multi-head) in which a plurality of recording elements are integrated and liquid discharge ports and liquid flow paths are integrated with high density is the mainstream. It has become.

  In general, an ink jet recording apparatus includes a recording unit having a carriage on which a recording head and a liquid tank for storing a liquid to be supplied are mounted, a conveying unit for conveying a recording material, and a control unit for controlling them. A recording head that discharges droplets from a plurality of liquid discharge ports is serially scanned in a direction (hereinafter, referred to as a main scanning direction) that intersects (for example, orthogonally) with a recording paper conveyance direction (hereinafter, referred to as a sub-scanning direction). On the other hand, the recording material is intermittently conveyed by an amount equal to the recording width in one serial scan at the time of non-recording.

  A color ink jet recording apparatus capable of recording a color image is also widely used. In this apparatus, ink droplets ejected from a plurality of recording heads corresponding to each of a plurality of colors of ink are superimposed on a recording material. By combining them, a color image is formed.

  In the ink jet recording method, characters, figures, and the like are recorded by selectively discharging liquid as fine droplets from a liquid discharge port onto a recording material in accordance with recording data. The ink jet recording method has advantages such as low noise because it is non-impact, low running cost, easy downsizing of the apparatus, and relatively easy colorization. For this reason, an ink jet recording apparatus is widely used as a recording apparatus used in combination with a computer, a word processor, or the like, or as a recording apparatus mounted on a copying machine, a printer, a facsimile, or the like used alone.

  Thus, the demand for inkjet recording apparatuses is increasing as an excellent recording means in a wide range of industrial fields, and it is required to be able to record higher quality images, and there is a further demand for higher speed. It is growing.

  In the conventional ink jet recording method, it is necessary to use a special coated paper having an ink absorbing layer in order to obtain a color image with high color development without ink bleeding on a recording material.

  However, in recent years, a method has been put into practical use that has the ability to record on plain paper that is used in large quantities in general printers and copiers by improving the ink. In addition, it is desired to cope with various recording materials having different ink absorption characteristics such as OHP sheets, cloths, and plastic sheets. In order to meet such a demand, development and commercialization of a recording apparatus capable of performing the best recording irrespective of the type of recording material are being promoted.

  Furthermore, regarding the size of the recording material, it is possible to record on a large-sized recording material that is required for recording on posters for events exhibitions, advertisements, etc. and woven fabrics such as clothing. Has also been required. Therefore, recently, as a printing system configured for business use, for example, a printing system capable of recording on recording paper of a large size such as A0 or B0 size has been configured, and a large inkjet printer is used. It has come to be.

  In such a commercial printing system that records on an A0 or B0 size or larger recording material, a paper receiving tray is prepared and the printed recording material is discharged to this tray. In addition to the configuration method, a configuration including a mechanism for winding a large recording material printed out has already started to spread.

  This is because, in recent years, it has been required to perform recording even on an extremely large recording material having a length of about several meters to several tens of meters.

  By the way, in the ink jet recording apparatus, in order to perform a recovery process for maintaining a good ink discharge state of the recording head, particularly when the recording operation is paused during page recording for a large recording material. There is. For example, the recording head may generate ink mist as ink is ejected from the ejection port, or may generate splash due to impact when the ejected ink lands on the recording medium. These mist, splash, and the like adhere to the ejection port surface of the recording head in which the ejection ports are arranged, and cause the ink ejection failure by closing the ejection port. The recovery process is a process for maintaining a good ink discharge state of the recording head in order to prevent the occurrence of ink discharge failure due to such factors.

  As one of the recovery processes, a blade made of an elastic material such as rubber is brought into contact with the ejection port surface of the recording head, and the blade and the recording head are relatively moved (usually, the recording head is moved). Thus, there is so-called wiping in which ink or the like adhering to the periphery of the ejection port is wiped off.

  As another recovery process, there is so-called preliminary ejection in which ink that does not contribute to image recording is ejected from an ejection port. When an image is recorded by selectively ejecting ink from a plurality of ejection ports of the recording head according to recording data, there are ejection ports that do not eject ink for a certain period of time. Since the ink in the vicinity of the ejection port remains exposed to the outside air, the viscosity increases, and when ink is ejected from the ejection port, the ink ejection amount and ejection speed decrease and the ink ejection direction is deflected. Or the like, which may cause ink ejection failure.

  Therefore, in order to remove such thickened ink, preliminary ejection is performed in which ink that does not contribute to image recording is ejected toward a predetermined portion of the recording apparatus.

  As another form of the recovery process, suction recovery is known. If bubbles are mixed or generated in the liquid path of the recording head or in the common liquid chamber due to, for example, continuous ejection of ink or long-term non-use of the recording apparatus, the bubbles will enter the liquid path. This may hinder ink supply and ink discharge operation, and may cause ink discharge failure. Mainly, in order to prevent such discharge failure, a cap made of a material such as rubber is brought into contact with the discharge port surface of the recording head, and then negative pressure is introduced into the cap. Then, suction recovery is performed in which the ink is forcibly sucked and discharged from the ejection port into the cap.

  The various recovery processes as described above are executed before image recording, after image recording ends, or between recording scans during image recording. By such a recovery process, it is possible to always maintain an appropriate ink discharge state of the recording head, and to perform high-quality recording while preventing deterioration in image quality. In particular, when recording is performed continuously on a relatively large recording surface, such as when poster output is performed by the above-described business printer, recovery processing is performed between recording scans in the recording operation. It is important to do.

  Here, the image quality of the ink jet recording apparatus will be further described. While color image output using multi-color ink is generalized in this way, in addition to the evaluation of image quality when printing only in monochrome, color developability Elements such as reproducibility, gradation, and uniformity are also important elements related to image quality.

  In particular, with regard to the uniformity of image recording, there is a slight variation in the production of nozzles in the multi-head manufacturing process, which affects the printing accuracy of each nozzle and causes uneven ink discharge during printing and the discharge direction. Deviation or the like occurs. The variation in the nozzle unit in the manufacturing process finally becomes the density unevenness of the output image, which causes the image quality to deteriorate.

  On the other hand, in recent inkjet recording apparatuses, for the purpose of improving image quality, a method of completing image recording by scanning a recording head a plurality of times in the main scanning direction with respect to the same recording area on a recording medium, so-called A multi-pass recording method is adopted.

  FIG. 7 is an explanatory diagram of the two-pass recording method in which the image recording is completed by scanning the recording head twice in the main scanning direction with respect to the same recording area on the recording medium as the multi-pass recording method. Here, the relationship between the position of the recording head H and the recording area of the image recorded on the recording medium P is shown.

  An image is recorded on the recording medium P by ejecting ink based on the image data while the recording head H moves in the main scanning direction (arrow X1 direction), and thus the recording head H scans once. Each time the printer operates, the recording medium P is conveyed in the sub-scanning direction (arrow Y direction) by a width corresponding to ½ of the width of the recording head H (hereinafter referred to as ½ band width).

  In FIG. 7, the position of the recording medium P is fixed, and the recording head H is expressed as moving in the direction opposite to the sub-scanning direction with respect to the recording medium P. In the first scanning operation, the image data thinned out for the neighboring pixels in the image data of one bandwidth corresponding to the width of the recording head H is recorded, and in the second scanning operation, the image of the one bandwidth is recorded. Of the data, image data that was not thinned out in the first scanning operation is recorded.

  Accordingly, the recording of the image on the recording medium P is completed by ½ bandwidth by the scanning operation of the recording head H twice. That is, the image data thinned out for the adjacent pixels is recorded in the first scanning operation, and the first scanning is performed in the second scanning operation. The image data not thinned out in the operation is recorded. Hereinafter, the first scan operation is referred to as the ½ pass, the second scan operation is referred to as the ½ pass, and the ½ pass for the ½ band width recording area on the recording medium P. An area where only the eye recording is performed is referred to as a 1/2 pass recording area, and an area where an image is completed after 2/2 pass recording is also referred to as a 2/2 pass recording area.

  FIG. 2 is a schematic diagram showing an image recorded during the recording operation when two-pass recording is performed.

  During the recording operation, the recording area corresponding to the ½ bandwidth at the rear end in the sub-scanning direction is a ½ pass recording area, and only the thinned image data is recorded by the ½ pass recording. The For this reason, the image is not completed in the half-pass recording area at the rear end, and the density of the area is approximately ½ that when the image is completed.

  However, in the multi-pass recording method as described above, when the recording operation is temporarily stopped in the middle of the recording operation, the time between the first scanning operation and the second scanning operation for the same recording area. An interval (hereinafter referred to as a recording time difference) changes with a temporary stop, resulting in a change in recording density, and density unevenness may occur.

  FIG. 3 and FIG. 4 are explanatory diagrams of the left unevenness caused by such a change in the recording time difference.

  FIG. 3 shows the state of ink permeation and fixing with respect to the recording medium 202 when the time between the first and second scan operations (1/2 pass and 2/2 pass) in the 2-pass printing method is short. FIG.

  As shown in FIG. 3A, the ink droplets 201a ejected in the ½ pass penetrate in a direction perpendicular to the surface of the recording medium 202 and a direction spreading on the surface as shown in FIG. A coloring matter such as a dye as a component physically and chemically binds to the recording medium 202. As shown in FIG. 4C, the ink droplet 201b ejected in the second pass also penetrates in the direction perpendicular to the surface of the recording medium 202 and the direction spreading on the surface, as shown in FIG. The ink droplets 201a that have landed first do not penetrate or fix much in the fixed area. The cause is considered to be that the ink droplet 201a that has landed earlier is still penetrating. Therefore, the ink droplet 201b that has landed later penetrates and fixes further downward in the region where the ink droplet 201a that has landed earlier penetrates, as shown in FIG.

  FIG. 4 is a diagram schematically showing the state of ink permeation and fixing with respect to the recording medium 202 when the time between the 1/2 pass and the 2/2 pass in the 2-pass printing method is long.

  As shown in FIG. 4A, the ink droplet 201a ejected in the 1/2 pass penetrates in a direction perpendicular to the surface of the recording medium 202 and a direction spreading on the surface, as shown in FIG. A pigment such as a dye, which is an ink component, is physically and chemically bonded to the recording medium 202. As shown in FIG. 5C, the ink droplet 201b ejected in the 2/2 pass and subsequently landed penetrates a relatively large amount in the region where the first landed 201a has penetrated and fixed. This is because the ink droplet 201a that has landed first sufficiently permeates and spreads, or the volatile component thereof evaporates, so that the amount of ink droplet 201a per unit volume of the recording medium 202 decreases, and the ink droplet 201b that landes later. It is thought that this is because it became possible to penetrate.

  As described above, the amount of ink fixed near the surface of the recording medium, that is, the amount of a pigment such as a dye differs depending on the change in the time interval between the 1/2 pass and the 2/2 pass. Further, since the recording density corresponds to the absorption of light of the dye fixed near the surface of the recording medium, the recording density varies depending on the time interval change between the 1/2 pass and the 2/2 pass.

  Therefore, when an image is recorded by the multi-pass recording method, if the recording is interrupted due to the temporary stop, the recording image before and after the interruption is left ununiformly.

  Therefore, in Patent Document 1, the ink supply operation and recovery in the middle of the printing operation are performed by performing the printing pause after completing the multi-pass printing until halfway before temporarily stopping the printing operation in the middle of the printing operation. A device that can avoid uneven printing even when processing is disclosed. As a result, there is no multi-pass incomplete area at the time of transition from the printing operation state to the resting state, and therefore density unevenness is considerably improved.

  However, according to this method, with respect to the image formation for completing the pass before the suspension of printing, a plurality of reciprocal printing scans are executed while the conveyance of the recording material is stopped. It is understood that density unevenness that may be caused by variation in nozzle units that occurs in the head manufacturing process occurs due to ink ejection from only predetermined nozzles of the head. Currently, further improvements are desired.

  In addition to the above, Patent Documents 2 and 3 and the like have been proposed as examples of methods for reducing the influence of density unevenness.

JP 2000-015868 A JP 11-245393 A JP 2001-171147 A

  However, considering from our experience the degree of influence of the density unevenness of interest, all of these proposals have already been made despite the fact that the influence of the density unevenness is large in the image area where the print density of the recorded image is high. The execution of the head recovery process is started based on the determination based on the number of recorded pixels in the area where image formation has been completed and the print length parameter recorded so far. That is, there has been no function that allows the user to select the timing for executing the recording pause according to the original image itself.

  Accordingly, an object of the present invention is a density resulting from a temporary stop that occurs in the middle of image formation by the multi-pass method, which often occurs when a long output printing is performed in a so-called multi-pass recording method. An object of the present invention is to provide an ink jet recording apparatus capable of reflecting the intention of an operator or general user who operates a printing apparatus with respect to the position of a printing area where unevenness occurs.

In order to achieve the above object, in the apparatus of the present invention described in claim 1, the recording head is used for the same recording area on a recording medium using a recording head capable of discharging ink from a plurality of discharge ports. In an ink jet recording apparatus that records an image by scanning a plurality of times and performs image formation by a multipass recording method capable of temporarily stopping image recording.
Determining means for determining whether to permit suspension of the page recording operation by performing threshold determination for the size of the recorded image formed and threshold determination for the number of recording pixels, and threshold determination for the size of the recorded image Threshold value prepared in advance as a threshold value for the size of the recorded image Is compared with the threshold value set by the user. When the threshold value set by the user is small, the determination condition for the number of recorded pixels is ignored, and when the threshold value set by the user is large, the operation is performed throughout the page recording. An image is formed using a thinning mask having a light image density as a thinning mask for multi-pass printing.

  According to the present invention, a function that allows the user to set a preferred position for the user as the pause position when the printing operation is paused in the so-called multi-pass printing method is provided. Can be positioned.

  In addition, when the setting is made to execute midway suction before the scan position corresponding to B0, which is the original midway suction execution position, the determination condition for dot count is not referred to. Even if the number of recording pixels does not reach the original halfway suction execution condition, halfway suction can be reliably performed in the user's requested recording area.

  If the user has set the halfway suction execution start timing larger than the scan position corresponding to B0, the dot count value threshold is not changed, but the density of the thinning mask is changed. The load on the multi-head can be reduced, and a page recording operation to a larger size can be handled.

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

(Basic configuration of recording device)
FIG. 5 is a front view showing an ink jet recording apparatus according to an embodiment of the present invention.

  In FIG. 5, reference numeral 2 denotes a recording apparatus main body including a paper transport system unit. This recording apparatus performs recording on a relatively large recording sheet (recording medium). Reference numeral 1 denotes a carriage. By mounting 12 recording heads 5 and moving in the main scanning direction indicated by arrows X (X1, X2), recording scanning of the recording paper (recording medium) of the recording head 5 is possible. Become.

  That is, the carriage 1 is guided and supported by the guide shaft 11 so as to be movable in the main scanning direction along the guide shaft 11 and is reciprocated in the main scanning direction by the driving force transmitted through the belt 13. In addition to the cyan, magenta, yellow, and black inks used as the ink to be ejected from the recording head 5, a total of six colors including light cyan and light magenta for the purpose of reducing graininess are employed.

  For the purpose of improving the recording speed, two recording heads 5 are used for one color ink. That is, two sets of recording heads 5 in total for six inks of six colors, one X1 direction in the main scanning direction (hereinafter referred to as the forward scanning direction) and the other X2 direction (hereinafter referred to as the backward scanning). Are arranged so as to be targeted. As a result, recording is performed by the reciprocal recording of the forward scanning and the backward scanning of the recording head 5 with the same ink ejection order from the 12 recording heads 5 during the forward scanning in the X1 direction and the sub-scanning in the X2 direction. High-quality images can be recorded while increasing the speed.

  In addition, two recording heads 5 for each color of ink are provided with ejection openings capable of ejecting ink in a line with the same pitch along the conveyance direction of the recording paper. The recording heads 5 may be arranged so that the outlet row and the ejection port row of the other recording head 5 are shifted by a half pitch in the recording sheet conveyance direction. In this case, the recording density in the conveyance direction of the recording paper can be doubled as compared with the case where one recording head 5 is used for one color ink. The recording apparatus is not necessarily limited to a configuration in which reciprocal recording is performed by forward scanning and backward scanning of the recording head 5, and may be configured to perform unidirectional recording in which recording is performed by only one reciprocal scanning.

  Reference numerals 30A, 30B, 30C, and 30D denote recovery mechanisms that perform suction recovery processing as recovery processing for maintaining a good ink discharge state of the recording head 5 and protect the recording head 5 when the recording head 5 is not used. . That is, these recovery mechanisms 30A, 30B, 30C, and 30D include a cap that can come into contact with the discharge port surface of the recording head 5 on which the ink discharge port is formed. By introducing a negative pressure from a pump (not shown) into the cap after being brought into contact with the surface, ink that does not contribute to image recording is forcibly sucked and discharged from the ejection port of the recording head 5 into the cap. . The cap protects the ejection port of the recording head 5 by contacting the ejection port surface when the recording head 5 is not used.

  Reference numeral 31 denotes a preliminary discharge ink receiving box that receives ink discharged by the preliminary discharge operation of each recording head 5. Preliminary ejection is another recovery process for the recording head 5, and ink that does not contribute to image recording is ejected from the ejection port toward the preliminary ejection ink receiving box 31. Reference numeral 32 denotes a wiping mechanism for performing a wiping operation on the discharge port surface of each recording head 5. The wiping is another one of the recovery processing for the recording head 5, and a blade made of an elastic material such as rubber is brought into contact with the discharge port surface of the recording head 5 so that the blade and the recording head 5 are relative to each other. By moving (in the case of this example, the recording head 5 is moved), ink or the like adhering to the periphery of the ejection port is wiped away.

  When the recording apparatus configured as described above receives recording data from the host apparatus, the carriage 1 is moved along the guide shaft 11 in the main scanning direction (in the main scanning direction (in order to record an image on a recording sheet sent by a paper transport unit not shown). An image for one band is recorded on the recording paper by ejecting ink from the recording head 5 while moving in the X1 or X2 direction. Then, the recording sheet is conveyed in the sub-scanning direction intersecting with the carriage 1 (orthogonal in this example) by the paper conveying unit.

  In order to detect the movement position of the carriage 1, an encoder film 12 is disposed along the movement path of the carriage 1. That is, the encoder sensor mounted on the carriage 1 can detect the encoder film 12, and the movement position of the carriage 1 can be detected based on the detection signal. Further, based on the detection signal of the encoder sensor, the carriage 1 is controlled to move to a predetermined home position (in this example, a position corresponding to the recovery mechanisms 30A, 30B, 30C and 30D).

  In each recording head 5, for example, 256 ejection openings are arranged at a density of 600 dpi (dots / inch) so as to be aligned in the sub-scanning direction, and ink can be ejected from each ejection opening. The method of discharging ink from the discharge port is arbitrary, and for example, a method of discharging using a piezo element or a method of discharging using heat generated by an electrothermal transducer (heater) may be used. The recording head 5 of this example is configured to eject ink using the heat generated by the electrothermal transducer. That is, an electrothermal converter is provided in each ink liquid path communicating with each ejection port, and the ink in the ink liquid path is locally heated by the heat energy generated from the electrothermal converter to cause film boiling. The ink is ejected from the ejection port corresponding to the ink liquid path by the pressure at that time.

(Recording device control system)
FIG. 6 is a diagram showing the configuration of an image recording apparatus equipped with an ink jet recording head according to a typical embodiment of the present invention.

  As shown in FIG. 6, reference numeral 601 denotes a CPU, and a ROM 602 and a RAM 603 are connected to its internal bus. The CPU 601 reads the program from the ROM 602 and executes the program by repeating read / write to the RAM 603. Reference numeral 604 denotes an interface that is connected to an external host device (not shown) and transfers a print command and image data to be printed by the main body, and is connected to the CPU 601 and a band memory 607 described later. Reference numeral 605 denotes an operation / display unit that displays various key input operations and operation states on the apparatus, and is connected to the CPU 601.

  When the operation setting of the recording apparatus main body is changed from the host via the interface 604, the memory contents at a predetermined position in the RAM 603 are changed via the CPU 601. Reference numeral 606 denotes a motor driver that controls a carriage driving motor. The motor driver 606 is connected to and controlled by the CPU 601 and outputs a motor driving signal to the connected motor 607. Reference numeral 608 denotes a motor driver that controls a conveyance system driving motor, which is connected to the CPU 601 and controlled, and a motor driving signal is output to the connected motor 609.

  Reference numeral 610 denotes a band memory, and image data transferred from a host (not shown) is temporarily stored in the page recording. Image data for printing is received via the interface 604, and image data necessary for printing an area divided in accordance with a predetermined width output for each scan of the carriage is controlled by the CPU 601. Stored.

  The band memory 610 outputs image data in bandwidth units to the multi-pass data processing unit 611 in accordance with the drive timing of the carriage. The multipass data processing unit 611 performs the thinning process by causing the image data thinning mask data for multipass printing to act on the image data. Reference numeral 612 denotes a head controller whose output is input to the multi-head 613. The head controller 612 drives the multi-head 613 so that printing of an area divided into a predetermined width is executed while the carriage performs one scan operation under the control of the CPU 601. The multi-head 613 is controlled by the head controller 612, and ejects ink from a plurality of ink ejection ports formed on the recording head, and executes printing for one scan while synchronizing with the carriage operation.

  Next, the operation of the present invention will be described with reference to FIGS. Here, FIG. 1 is an operation flowchart showing the image forming operation of the present invention. FIG. 8 shows an example of print parameters received from the host device during the page recording operation.

  First, from the host side, receive operation parameters related to the printing operation, such as the print start command, image size, leading and trailing margins, and parameters for specifying the paper feed stage and paper type used for printing. Store in the RAM 603 (step 101). At this time, the set value of the print stop position set value specified by the user via the printer driver is also stored. The print parameters received here are stored in the RAM 602 as shown in FIG.

  In FIG. 8, reference numeral 813 denotes a print stop position set value. First, a pause determination is performed using this set value as a threshold value for the number of print scans. If a predetermined execution condition is reached, the print operation is interrupted and the suction operation is performed halfway. Shall be performed. The print stop position setting value 813 may be set by the user operating the operation / display unit 605 and stored in the RAM 603.

  Next, the CPU 601 reads out the parameters received in step 101 and initializes internal variables such as the total number of recording scans and the total number of recorded pixels at the time of page recording. Also, select a data thinning mask for multi-pass printing based on the specified print mode and set paper type, set the area for storing images in the memory on the main unit side, and record for one page. Operation parameters related to printing in page units are set on the main body side, such as calculation of the scheduled total number of recording scans for completion (step 102).

  Here, if the print stop position setting value 813 is larger than the number of print scans corresponding to the B0 size (step 103), the CPU 601 sets the density to 100% which is not a thinning mask originally specified by the user. For example, a data mask having a density of 90% is selected from the original thinning mask, and this is set in the multipass data processing unit 611 as a data thinning mask used for page printing by the multipass method (step 105). The thinning data of both the data thinning mask for 100% density printing and the data thinning mask for 90% density printing is a so-called random mask pattern in which the mask data is generated by random numbers rather than a fixed mask pattern. It is possible to obtain a printing result that is more preferable if the data is generated by.

  In this step 105, halfway suction execution determination is performed based on the number of B0 size recording pixels, so that a lighter image is used as a data thinning mask when the halfway suction execution timing specified by the user is larger than the B0 size. It makes sense that the mask to be formed is selected.

  Note that the mask data for data thinning is random mask data stored in advance in the ROM 602 and RAM 603, but the mask data is not limited to a method stored in advance. For example, it may be received from the host device in step 101 following reception of the print parameter.

  In step 103, if the print stop position setting value 813 is smaller than the number of scans corresponding to the B0 size, the CPU 601 uses the data thinning mask data specified by the user as the mask data used for page recording. It is set in the data processing unit (step 104).

  Subsequently, the CPU 601 instructs the motor driver 608 on the number of drive steps based on the paper cassette designation and the leading edge margin designation received in step 101. Then, the LF motor driver 608 drives the LF motor 609 to convey the paper to the print start position (step 106).

  Then, the CPU 601 instructs the CR motor driver 606 to move the carriage to a predetermined position for starting printing. Then, the CR motor driver 606 drives the CR motor 607 to move the carriage to the print scan start position. Further, the CPU 601 performs data processing operation settings in the multi-pass data processing unit 611 and performs operation settings related to head drive control in the head controller 612 in order to execute print scans. The operation setting related to is performed (step 107).

  Subsequently, the CPU 601 instructs the host interface 604 to start data reception. As a result, image data transfer from the host to the band memory 610 via the host interface 604 is started. Further, the CPU 601 reads out from the band memory 610 to calculate the number of pixels (dot count) actually printed in the print scan to be performed for each ink color, counts the total number of print pixels up to the present, and stores this in the RAM 603. Store (step 108).

  Then, the CPU 601 compares the counter for counting the number of recording scans stored in the RAM 603 with the print stop position setting value 813. If the total number of scans so far is the same as the print stop position set value 813 (step 109), the CPU 601 advances the process to the next step 110. In step 110, the print stop position set value 813 is compared with a numerical value indicating the number of scans corresponding to the B0 size. Here, if the print stop position setting value 813 is smaller than the B0 size (step 110), the CPU 601 temporarily interrupts the page recording operation and sets the multi-value regardless of the dot count value recorded so far. The head suction recovery process is executed. Thereafter, the total recording scan number and the total recording pixel number that are referred to for determining whether or not halfway suction is to be executed are initialized to zero values (step 111).

  In step 110, if the print stop position setting value 813 is smaller than the B0 size, the process proceeds to the next step 112. In this step 112, the CPU 601 reads out from the RAM 603 and compares the number of recorded pixels recorded so far with the dot count threshold value for executing halfway suction. Here, if the number of recorded pixels recorded so far is larger than the dot count threshold value for executing halfway suction (step 112), the CPU 601 advances the process to step 111.

  In step 112, if the number of recorded pixels recorded so far is not larger than the dot count threshold value for executing halfway suction, the CPU 601 proceeds to the next step 113.

  The CPU 601 then instructs the CR motor driver 606 to drive the CR motor 607 in order to execute a print scan. In this carriage scanning operation for printing, an encoder signal (not shown) changes in accordance with the driving of the carriage. In accordance with the change, the image data is output from the band memory 610 to the multipass data processing unit. In the multi-pass data processing unit 611, image data thinning processing for multi-pass printing is executed, and the output image data is output to the head controller 612.

  The image data input to the head controller 612 is further output to the multi-head 613 in accordance with the drive control set for the multi-head 613. As described above, the encoder output value is changed by driving the carriage, whereby the image data stored in the band memory 610 is output from the multi-head 613, and the image recording operation on the recording paper is executed. Then, the recording scan number counter is incremented by one (step 113).

  When the recording scan is completed in step 113, the CPU 601 then drives the motor driver 608 to drive the motor in accordance with the set multi-pass printing mode in order to execute conveyance of the recording paper for multi-pass printing. Specify the number of steps. Then, the LF motor driver 608 drives the LF motor 609 and conveys the sheet by a predetermined amount for multi-pass printing (step 114).

  In this way, the CPU 601 executes one print scan for multi-pass printing.

  Here, the CPU 601 determines whether or not a predetermined recording scan for one page has been completed. When execution of the print scan of the predetermined number of scans set at the start of the page recording operation has been completed (step 115), the CPU 601 first feeds the paper to the cutter operation position, and then continues (not shown). The paper cutting operation is executed by operating the paper cutter (step 116), and then the printing operation is terminated.

  However, if all the print scans have not been completed in step 115, the process proceeds to step 108, and the second and subsequent print scans are executed.

  In the present embodiment, as one image forming apparatus based on the multi-pass recording method in which image formation is performed by executing a plurality of recording scans, one recording scan and one sheet feeding are alternately performed. In this embodiment, for example, as shown in Japanese Patent Application Laid-Open No. 2000-015868, a multi-image forming apparatus that performs image formation by stopping paper feeding when printing is interrupted and performing a plurality of scans is described. Needless to say, the method can be applied to the pass method.

(Other embodiments)
The present invention can be applied to various ink jet recording apparatuses capable of recording an image using a recording head having a plurality of ink discharge ports. For example, a recording apparatus that records color images using inks having the same or different colors, a recording apparatus that records multi-tone images using inks of the same color and different densities, and a combination of these functions Similar effects can be achieved by similarly applying the present invention to the apparatus.

  Furthermore, the present invention provides a configuration using a replaceable ink jet cartridge in which a recording head and an ink tank as recording means are integrated, a recording head and an ink tank as recording means as separate bodies, and an ink between them. The same effect can be obtained by applying the present invention similarly to any arrangement of the recording means and the ink tank, such as a configuration of connecting with a supply tube or the like.

It is an operation | movement flowchart which shows operation | movement of the inkjet recording device of this invention. It is explanatory drawing of the recorded image in the middle of the recording operation at the time of performing two-pass recording. FIG. 6 is an explanatory diagram showing how ink permeates and fixes when the time interval between the 1/2 pass and the 2/2 pass is short in 2-pass printing. FIG. 5 is an explanatory diagram of ink penetration and fixing when the time interval between the 1/2 pass and the 2/2 pass is long in 2-pass printing. 1 is a front view of an ink jet recording apparatus according to an embodiment of the present invention. It is a block block diagram of the control system in the inkjet recording device of this invention. FIG. 10 is an explanatory diagram of a relationship between a recording head position and a recording area when two-pass recording is performed as multi-pass recording. It is an example of the printing parameter received from the host device during the page recording operation.

Explanation of symbols

1 Carriage 2 Device body (including transport system unit)
DESCRIPTION OF SYMBOLS 5 Recording head 11 Guide shaft 12 Encoder film 13 Belt 30A-, 30D Recovery mechanism 31 Preliminary discharge ink receiving box 32 Wiping mechanism 101a, 101b Ink droplet 102 Recording medium 601 CPU
602 ROM
603 RAM
604 interface 605 operation / display unit 606 CR motor driver 607 CR motor 608 LF motor driver 609 LF motor 610 band memory 611 multipath data processing unit 612 head controller 613 multi head

Claims (1)

Using a recording head capable of ejecting ink from a plurality of ejection openings, an image is recorded by scanning the recording head a plurality of times with respect to the same recording area on the recording medium, and image recording is temporarily stopped. In an inkjet recording apparatus that performs image formation by a possible multi-pass recording method,
Determining means for determining whether to permit suspension of the page recording operation by performing threshold determination for the size of the recorded image formed and threshold determination for the number of recording pixels, and threshold determination for the size of the recorded image An input means for allowing the user to set the threshold value, and a data thinning mask having a different thinning rate as a thinning mask for the multi-pass recording method,
A threshold value prepared in advance as a threshold value for the size of the recorded image is compared with a threshold value set by the user.If the threshold value set by the user is small, the determination condition for the number of recorded pixels is ignored, An ink jet recording apparatus, characterized in that when a threshold set by a user is large, an image is formed using a thinning mask whose image density is reduced as a thinning mask for multi-pass printing that operates throughout the entire page recording.

Images