Inkjet printing apparatus, control method and program

Abstract

To highly accurately determine whether or not to execute an idle suction operation before recording in order to suppress ink overflow in a cap until recording of an image ends.SOLUTION: An ink jet recording device predicts an ink amount in a cap at a time point at which recording due to a recording command ends, determines execution of an idle suction operation on the basis of the predicted ink amount after recording, and achieves both of suppression of ink overflow and suppression of downtime due to the idle suction operation.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an inkjet printing apparatus, a control method, and a program. [Background technology]

[0002] Inkjet recording devices that record images by depositing ink onto a recording medium are known. In such inkjet recording devices, while an image is not being recorded, water in the ink evaporates from the nozzles (ejection ports) that eject the ink, causing the ink to thicken, which can result in ink ejection problems from the nozzles. To prevent such ejection problems, a so-called preliminary ejection is performed, in which the ink that has thickened in the nozzles is ejected toward the cap. To prevent the ink that has accumulated in the cap due to this preliminary ejection operation from overflowing, a discharge operation is required to discharge the ink from the cap. This discharge operation is called an idle suction operation. Furthermore, performing the idle suction operation takes a certain amount of time.

[0003] Patent Document 1 describes a method for determining whether to perform an idle suction operation before a printing operation based on the size of the printing medium. With this configuration, the idle suction operation is omitted depending on the size of the printing medium, and the printing time required per sheet of printing medium can be reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-21984 Summary of the Invention [Problem to be solved by the invention]

[0005] As disclosed in Patent Document 1, in the method of determining whether or not to perform an empty suction operation based on the size of the recording medium, there are cases where the empty suction operation is not omitted even when it is not necessary, and cases where the empty suction operation is omitted even when it is necessary.

[0006] In response to such a problem, an object of the present invention is to determine whether or not to perform an empty suction operation while suppressing ink overflow from the cap. [Means for solving the problem]

[0007] The recording apparatus comprises a recording head provided with a plurality of nozzles for ejecting ink, a transport means for transporting a recording medium relative to the recording head, a cap for receiving ink ejected from the recording head by preliminary ejection, an ejection means for performing an ejection operation for ejecting ink from the cap, and an acquisition means for acquiring a post-recording ink amount indicating the amount of ink in the cap at the time when recording according to the recording command is completed when a recording command for the recording medium is input, wherein the ejection means performs the ejection operation before recording according to the recording command starts when the post-recording ink amount acquired by the acquisition means exceeds a threshold value. [Effects of the Invention]

[0008] The present invention can determine whether to perform an empty suction operation while preventing ink from overflowing from the cap. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing the entire recording apparatus. [Figure 2] FIG. 2 is a perspective view showing a drive mechanism of the recording apparatus. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 4 is a perspective view showing a drive transmission configuration from a conveying roller to a pump mechanism. [Figure 6] FIG. [Figure 7] FIG. 2 is a block diagram showing an outline of the control configuration of the printing apparatus. [Figure 8] 1 is a vertical cross-sectional view showing the entire recording apparatus according to a first embodiment. [Figure 9] 5 is a flowchart showing control of the recording apparatus according to the first embodiment. [Figure 10] 10 is a correspondence table between recording settings and parameters used for calculation according to the first embodiment. [Figure 11] 10 is a flowchart showing control of a recording apparatus according to a second embodiment. [Figure 12] 10 is a flowchart showing a process for determining whether or not to perform idle suction using a dot count value during printing according to the second embodiment. [Figure 13] 11 is a flowchart showing control of a recording apparatus for determining a recovery operation before recording according to the third embodiment. [Figure 14] 10 is a flowchart showing control of a recording apparatus for determining a pre-recording cleaning flag according to a third embodiment. [Figure 15] 10 is a flowchart showing control of a recording apparatus for determining an empty suction flag according to a third embodiment. [Figure 16] FIG. [Figure 17] 11 is a flowchart showing control of a recording apparatus for determining a recovery operation after recording according to the third embodiment. [Figure 18] 11 is a flowchart showing the control of the printing apparatus for determining the post-printing cleaning flag according to the third embodiment. [Figure 19] 10 is a table showing the priority order of cleaning flags according to the third embodiment. [Figure 20] 10 is a flowchart showing control of a recording apparatus for determining a dot count wiping flag according to a fourth embodiment. [Figure 21] 10 is a flowchart showing control of a recording device when replacing a recording medium according to the fourth embodiment. [Figure 22] 10 is a flowchart showing control of a recording apparatus for determining a post-recording cleaning flag according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a cross-sectional view showing the entire inkjet recording apparatus according to this embodiment. When a recording command is sent from a host device such as a PC, the control unit drives a motor 21, which serves as a drive source for each mechanism. The motor 21 is illustrated in FIG. 2, which will be described later. The motor 21 drives the paper feed mechanism 2, intermediate roller 6, transport roller 10, which is located downstream of the intermediate roller 6, and discharge roller 12, which is located downstream of the transport roller 10. The paper feed mechanism 2 pushes and transports the recording media P loaded in the paper feed tray 1, and separates them one by one by striking them against a separating member 4. The separated recording media P are transported by the paper feed mechanism 2 to the intermediate roller 6 and its paired pinch roller 7. When the leading edge of the recording medium P passes through the intermediate roller 6, it hits the outer periphery of a U-shaped paper guide, and the transport direction is reversed while continuing along the paper guide, reaching the transport roller 10 and its paired pinch roller 11. When the leading edge of the recording medium P reaches the nip between the transport rollers 10, the leading edge position is adjusted according to the type of recording medium, and skew of the recording medium is corrected. This adjustment of the leading edge position is also called leading edge registration. When leading edge registration is performed, the transport rollers 10 can be rotated by the motor 21 in a direction to return the recording medium P, i.e., in the reverse direction of the transport direction. On the other hand, the intermediate rollers 6 are configured to always rotate in the forward direction of the transport direction, i.e., in the direction in which the recording medium P is discharged, regardless of the direction in which the motor 21 is driven. This configuration of the two rollers allows the recording medium to form a loop just before the transport rollers 10. When the recording medium P reaches the transport rollers, the drive direction of the motor 21 is reversed, and the transport rollers 10 are rotated in a direction to rewind the recording medium. Then, the transport rollers 10 are rotated in the forward direction again, and the recording medium P is transported in the direction in which it is discharged, thereby completing leading edge registration. After leading edge registration, the recording medium P is transported onto the platen, and the paper feeding operation is completed.

[0012] A recording unit 714 is disposed on the platen, which scans relative to the recording medium P. The recording apparatus of this embodiment is a so-called serial recording type recording apparatus, in which the recording unit 714 scans in a scanning direction (X direction in the figure) that intersects with the transport direction (Y direction in the figure). During this scanning, ink is ejected as droplets from nozzles (ejection openings) of a recording head 717 mounted on the recording unit 714 onto the recording medium P transported on the platen, and an image is recorded on the recording medium P.

[0013] FIG. 16 is an image diagram of the print head 717, and FIG. 16(a) is a conceptual diagram showing the nozzle surface (discharge port surface) on which nozzle rows are arranged, each row having a plurality of nozzles (discharge ports) that discharge ink. FIG. 16(b) is a diagram showing the nozzle arrangement of each nozzle row. In each nozzle row, the nozzles are arranged at intervals of 600 dpi in the Y direction in the figure. Two nozzle rows for each ink color are arranged in a staggered pattern, offset by 1200 dpi in the Y direction. In other words, the print resolution in the Y direction for each ink color is 1200 dpi.

[0014] The print head 717 is provided with an ink flow path (not shown) for supplying ink to each nozzle. Each nozzle is provided with a print element that generates energy for ejecting ink as droplets. In this embodiment, electrothermal conversion elements that convert electrical energy into thermal energy are used as the print elements, but this is not limiting and piezoelectric elements or the like may also be used.

[0015] In Figure 16(a), rows a and b are nozzle rows in which nozzles that eject cyan ink are arranged, rows c and d are nozzle rows in which nozzles that eject magenta ink are arranged, and rows e and f are nozzle rows in which nozzles that eject yellow ink are arranged. Similarly, rows g and h are nozzle rows in which nozzles that eject black ink are arranged. Each of the nozzle rows corresponding to the color inks cyan, magenta, and yellow has 256 nozzles arranged therein, and the nozzle row corresponding to black ink has 640 nozzles arranged therein.

[0016] The recording operation records an image by repeating the aforementioned conveyance by the conveyance roller 10 and the recording scan by the recording unit 714. In this embodiment, a so-called multi-pass recording method is performed in which the recording of an image on a unit area is completed by scanning the unit area on the recording medium multiple times. A recording scan by the recording unit 714 is also called a "pass," and the number of scans by the recording head 717 to complete recording on a predetermined unit area is called the "number of passes." After the image recording is completed, the recording medium P is conveyed in the forward conveyance direction by a pair of discharge rollers 12 and spurs 13, and is discharged.

[0017] 2 is a perspective view showing the drive mechanism of the inkjet recording apparatus of this embodiment, and shows the details of the drive transmission mechanism that transmits the drive force of the motor 21 to the transport roller 10 and the intermediate roller 6. In this embodiment, both the transport roller 10 and the intermediate roller 6 are driven by the motor 21 in common. This allows for the size and cost of the recording apparatus body to be reduced.

[0018] A gear (not shown) attached to the rotating shaft of the motor is connected via an idler gear 22 to a conveying input gear 23 attached to the shaft of the conveying roller 10. A code wheel (not shown) with markings is attached to the conveying input gear 23, which can detect the amount of rotation of the motor. By reading this with an encoder sensor (not shown), the amount of rotation of the conveying roller 10 can be controlled. A conveying output gear 24 is attached to the other end of the shaft of the conveying roller 10. Driving force is transmitted from this conveying output gear 24 via an idler gear 25 to a sun gear 31. The sun gear 31 is configured as a clutch gear.

[0019] FIG. 3 is a perspective view showing the configuration of the clutch gear shown in FIG. 2. As shown in this figure, a spring 33 is provided inside the sun gear 31. When the sun gear 31 rotates forward, the spring 33 tightens, allowing the sun gears 31 and 32 to rotate together. On the other hand, when the sun gear 31 rotates reversely, the spring 33 opens. Therefore, when a load is applied to the sun gear 32, the sun gears 31 and 32 slip and cannot rotate together. In addition, a swing arm 34 is provided on the axis of the sun gear 31, and a planet gear 35 is attached to the swing arm 34. A swing arm spring 36 is provided between the planet gear 35 and the swing arm 34, so that when the sun gear 31 rotates due to friction, the swing arm 34 also rotates together. A stage 38 of a multi-stage gear 37 is connected to the sun gear 32. In addition, a stage 39 of the multi-stage gear 37 is attached in a position where it can be connected to the planet gear 35.

[0020] With this configuration, when the sun gear 31 rotates forward in the direction of arrow s, the drive input to the sun gear 31 is transmitted to stage 38 of the multi-stage gear 37 by the sun gear 32, which rotates together with the sun gear 31. On the other hand, when the sun gear 31 rotates reversely in the direction of arrow t, the swing arm 34 moves in the direction of arrow u in the figure, connecting the planet gear 35 with stage 39 of the multi-stage gear 37, and transmitting the drive to the multi-stage gear 37. Note that because the sun gear 32 is a clutch gear, the sun gear easily slips during reverse rotation and does not interfere with the drive. With this transmission method, the rotation direction of the multi-stage gear 37 is the same whether the sun gear 31 rotates forward or reverse.

[0021] FIG. 4 is a perspective view showing the recovery mechanism. The recovery mechanism of this embodiment is used to maintain the ink ejection performance of the print head 717. In this figure, the slider 40 follows the movement of the print head 717 in the reciprocating movement direction and is slidable in an area outside the printing area where an image is printed. The slider 40 is also movable in a direction perpendicular to the nozzle surfaces of the color inks and the black ink of the print head 717, i.e., in the ink ejection direction. This movement of the slider 40 enables the caps 41 and 42 to come into contact with and separate from the nozzle surface of the print head 717.

[0022] Cap 41 is a cap for cyan, magenta, and yellow color inks, and cap 42 is a cap for black ink. The slider 40 is equipped with cap holders 44 and 45. Furthermore, in response to the movement of the recording head 717, the slider 40 is movable in an area different from the recording area in the direction of movement of the recording unit 714 and in the direction in which the black and color recording heads 717 approach or move away from the caps. Pump tubes 51a and 51b are connected to the caps 41 and 42, respectively, and the pump tubes 51a and 51b are connected to a pump mechanism including a suction pump that generates negative pressure. Driving this suction pump enables a recovery operation to be performed, in which ink is sucked from each nozzle through the caps.

[0023] FIG. 5 is a perspective view showing the drive transmission configuration from the conveying roller 10 to the pump mechanism, and FIG. 6 is a perspective view showing the pump mechanism. A pump roller 64 is attached to the pump roller holder 62. The pump tubes 51a and 51b are inserted halfway around the inner wall of the pump base 60 and are rotatably inserted within the pump base 60. When the conveying roller 10 is rotated in reverse by driving the motor 21 with the recording head 717 capped, the driving force is transmitted to the pump roller holder 62 via the conveying output gear 24, the idler gear 25, and the pump drive gear 50. The pump roller 64 moves a cam provided on the pump roller holder 62, and the pump tubes 51a and 51b are crushed by the inner wall of the pump base 60 and the pump roller 64. Further reverse rotation of the conveying roller 10 generates negative pressure inside the pump tube.

[0024] When negative pressure is generated with the nozzle surface of the recording head 717 capped by the caps 41 and 42, ink can be sucked from the nozzles of the recording head 717 through the caps 41 and 42. On the other hand, when negative pressure is generated with the nozzle surface of the recording head 717 not capped, a discharge operation (idle suction operation) can be performed in which ink accumulated in the caps by preliminary ejection or the like is sucked and discharged. In addition, in the idle suction operation, by squeezing each of the pump tubes 51a and 52b, ink can be sucked from the nozzles or idle suction can be performed individually for each of the caps 41 and 42.

[0025] To release the negative pressure in the pump tube after the suction operation of sucking ink is completed, the pump roller holder 62 is rotated in the opposite direction. That is, the transport roller 10 is rotated in the forward direction. The negative pressure in the pump tube is released by releasing the pump roller 64 from its crushed state of the pump tubes 51a and 51b. In this manner, the pump tube is driven by the motor 21, which drives both the transport roller 10 and the intermediate roller 6. Driving the motor 21 in the direction of reversing the transport roller 10 generates negative pressure in the pump tube. In this manner, in the recording apparatus of this embodiment, the suction operation is performed by generating negative pressure in the cap by reversing the transport roller 10. Therefore, when the recording medium is nipped by the transport roller 10, negative pressure cannot be generated in the cap without moving the recording medium in the Y direction. Therefore, when performing a capping operation in which the recording head 717 is brought into close contact with the cap 41 or 42, or an idle suction operation in which ink is discharged from the cap, it is necessary to release the nipped state of the recording medium by the transport roller.

[0026] FIG. 7 is a block diagram showing an outline of the control configuration of this embodiment. The control unit 72 includes a CPU, ROM, and RAM. The CPU executes each process according to programs stored in memories such as the ROM and RAM. The RAM is a volatile storage device that temporarily stores programs and data. The ROM is a nonvolatile storage device that stores table data and programs used in each process described below. The control unit 72 controls the following operations by outputting motor current control signals to motor drivers 73 and 712 in accordance with input from the operation panel 71 or a connected PC 710. The paper feed motor 74, which corresponds to the motor 21 that drives the above-mentioned conveyance rollers, drives the paper feed / discharge roller unit 76 via a conveyance drive transmission system 75 and a drive switching mechanism 77 in response to a signal input from the motor driver 73. The paper feed roller unit 78 and intermediate roller unit 79, which correspond to the above-mentioned conveyance roller 10 and intermediate roller 6, are also driven in the same way. The paper feed motor 74 drives the pump tube of the above-mentioned recovery unit.

[0027] A recording unit motor 713 drives a recording unit 714 by a signal input from a motor driver 712. Various sensors 711 provided in the paper transport unit and the recording unit 714 detect the position of the recording medium P, the number of rotations of the transport roller, the recording position of the recording unit 714, etc. The detected signals are input to a control unit 72, which outputs appropriate control signals to the motor drivers 73 and 712.

[0028] The control unit 72 drives the print head 717 by outputting print data to the head driver 716. The print data includes not only the image to be printed, but also preliminary ejection data for maintaining the ejection performance of the print head 717. In this embodiment, the preliminary ejection operations include pre-printing preliminary ejection, which is performed before a printing operation that records an image on a printing medium, printing preliminary ejection, which is performed during a printing operation, and standby preliminary ejection, which is prepared for when the next printing command is input. This preliminary ejection is performed to discharge ink that has thickened near the nozzles, and in this embodiment, ink is ejected onto the caps. Preliminary ejection of color inks is performed onto cap 41, and preliminary ejection of black ink is performed onto cap 42.

[0029] Figure 8 shows a cross-sectional view of an inkjet recording apparatus 801 of this embodiment. 802 is a recording medium P, which in this figure is roll paper 24 inches wide. 803 is a holder for setting the roll paper, 804 is a sensor that detects the presence or absence of a recording medium, and 805 is a pinch roller that is positioned opposite the transport roller 10 and nip the roll paper. 806 is a transport roller that is positioned downstream in the transport direction. 808 is a cutter that cuts the roll paper after recording is completed. This figure shows the roll paper 802 being nipped by the pinch roller 805. 809 is a tray for setting cut paper.

[0030] 9 is a flowchart of the process for determining whether to perform the dry suction operation in this embodiment. This process is started after a recording command is received and the paper feed operation is completed, and is performed separately for the cap 41 corresponding to the color inks and the cap 42 corresponding to the black ink. In this embodiment, the preliminary ejection is performed for both the cap 41 and the cap 42.

[0031] First, in step S901, the amount of ink M_1 in each cap at that time is obtained. Next, in step S902, information such as the print quality, print medium type, image size, cut mode, drying time setting, number of pages, and margin amount set by the user in the received print command is obtained. Then, based on the obtained information, the amount of preliminary ejection M_2, which is the amount of preliminary ejection to be performed until image printing based on the received print command is completed, is calculated. The method for calculating this amount of preliminary ejection M_2 will be described in detail later.

[0032] In step S903, the current ink amount in the cap M_1 and the preliminary ejection amount M_2 to be executed, which were acquired in steps S901 and S902, are added together. The result of this addition corresponds to the ink amount in the cap when printing is completed. The result of this addition is then compared with a threshold value X to determine whether it exceeds threshold value X. Here, threshold value X is a value less than the cap capacity. If threshold value X is exceeded, it is considered possible that ink may overflow from the cap by the time printing is completed, and therefore the ink currently stored in the cap should be discharged.

[0033] Therefore, if the value exceeds threshold X, the process proceeds to step S904, where the conveyance roller 10 is rotated in reverse, rewinding the roll paper 802 until the leading edge passes the sensor 804, and the pinch roller 805 releases the nip of the roll paper 802. In this embodiment, when the conveyance roller 10 is rotated in reverse, negative pressure is generated inside the cap, so when capping the nozzle surface or performing dry suction, it is necessary to release the nip of the roll paper 802. In step S905, the conveyance roller 10 is rotated in reverse with the cap separated from the nozzle surface of the print head 717, and dry suction is performed. This discharges the ink from inside the cap. After the dry suction is completed, in step S906 the roll paper 802 is fed again and nipped again. Then, in step S907, the image printing operation based on the print command is performed, and this process ends after printing is completed.

[0034] On the other hand, if it is determined in step S903 that the sum does not exceed the threshold value X, the above-described idle suction operation is not executed, and the process proceeds to the recording operation in step S907.

[0035] Here, we will explain the method for predicting the preliminary ejection amount M_2 ejected into the cap by the time the printing operation in response to a print command is completed in step S902. In this embodiment, the timing of preliminary ejection can be broadly divided into three types. First, pre-printing preliminary ejection is preliminary ejection that is performed until the printing medium feeding operation is completed. Next, during-printing preliminary ejection is preliminary ejection that is performed after the start of a printing operation, after the end of one scan of the print head 717, and before the start of the next scan. Finally, during-standby preliminary ejection is preliminary ejection that is performed after the end of a printing operation, in preparation for when the next print command is received.

[0036] The preliminary ejection amount M_2 is calculated by the following (Equation 1). M_2=M_A+M_B+M_C (Equation 1)

[0037] M_2 is the total amount of preliminary ejection executed in the printing operation in response to a print command, M_A is the amount of preliminary ejection before printing, M_B is the amount of preliminary ejection during standby, and M_C is the amount of preliminary ejection during printing. In this embodiment, M_2 is calculated for each of the caps 41 and 42. The calculation method for each preliminary ejection amount is based on the following (Equation 2) to (Equation 4). M_A=v×n×d_a (Equation 2) M_B=T_b / t×v×n×d_b (Formula 3) M_C=(l / l_n / P_max+(P_max-1)) / 2×v×n×d_c (Formula 4)

[0038] v is the amount of ink ejected per droplet, and n is the number of nozzles per cap. d_a is the number of shots ejected from one nozzle during preliminary ejection before printing, d_b is the number of shots ejected from one nozzle during preliminary ejection during standby, d_c is the number of shots ejected from one nozzle during preliminary ejection during printing, and T_b is the total standby time. t is the time interval during which preliminary ejection is performed during standby, and l is the length of the image. l_n is the nozzle length, which is a value that indicates the length in the transport direction of the arrangement of nozzles used in printing by a print command.

[0039] P_max is the number of passes, and in this case, it is the value when the number of printing passes is maximum. In the inkjet printing apparatus of this embodiment, controls such as power monitor control and leading edge control are implemented to increase the number of scans per specified unit area under specified conditions. Power monitor control increases the number of scans so that the number of ink droplets ejected per scan is below a threshold value, preventing the supply of power from being exceeded. Lead edge control is a control to prevent the recording medium from floating up and contacting the nozzle surface in the area before the leading edge of the roll paper 802 passes the paper discharge roller 12, thereby preventing degradation of image quality. This leading edge control optimizes the number of nozzles used and their positions to minimize the amount of floating of the recording medium and the fluctuation in floating amount between scans. It is difficult to determine whether to implement these controls for every scan before the start of printing, which would complicate processing and result in downtime. For this reason, these controls are assumed to be implemented and reflected in the formula as P_max.

[0040] In this embodiment, the values ​​of v, n, d_a, d_b, d_c, and t are set to predetermined fixed values. In this embodiment, the values ​​are v=6.2 [ng], n=1536, d_a=8, d_b=8, d_c=2, and t=1.6 [s] for the cap 41, and v=13.5 [ng], n=1280, d_a=100, d_b=13, d_c=3, and t=1.6 [s] for the cap 42.

[0041] T_b is the sum of the inter-page delay time and the waiting time on the cap in the cut mode selected by the user. The inter-page delay is the waiting time after recording is completed until the roll paper 802 is cut by the cutter 808. If the recorded material is dropped into a basket (not shown) immediately after the roll paper 802 is cut, the area on which the image was recorded may be rubbed and peeled off, resulting in a defective image. This type of image defect is particularly likely to occur on recording media that do not easily fix ink, such as film. To address this issue, providing a wait time between the end of recording and cutting to improve fixation can reduce image defects on the recorded material. The inter-page delay time can be set by the user via the host device or the operation panel 71.

[0042] The user can also select either auto cut or eject cut as the cutting method. Auto cut means that cutting is performed automatically immediately after recording has finished and after a specified delay time between pages has elapsed, and the waiting time on the cap associated with the cutting operation is equal to or less than the intermittent time of preliminary ejection during recording. With eject cut, the user can set the timing for cutting with the cutter 808 after recording has finished, and issue a command to execute the cutting operation from the host device or the main body UI at the time the user wants to cut.

[0043] In this embodiment, the maximum time that the print head 717 can wait on the cap with the roller nipping the print medium after printing an image is set to 300 seconds. During this time, the print head 717 waits without contacting the cap. After 300 seconds have elapsed, the print medium is automatically cut. During standby, preliminary ejection is performed at regular intervals. Because this preliminary ejection during standby increases the amount of ink in the cap, it is necessary to limit the standby time to 300 seconds to prevent ink from overflowing from the cap. Therefore, when the user selects eject cut, the maximum standby time (300 seconds in this embodiment) is reflected in T_b. Furthermore, the data length received as a print signal is also reflected in the calculation of l.

[0044] Figure 10 is a table showing the correspondence between the user's print settings and the values ​​used to calculate each preliminary ejection amount. Since l_n and P_max differ depending on the type of print medium, print mode, and print quality set by the user, they are converted into values ​​used in the calculation formula based on a correspondence table with user settings like this one.

[0045] As described above, in response to input of a recording command, the amount of preliminary ejection to be performed until the end of recording is predicted. Then, based on the prediction result, it is determined whether or not to perform an idle suction operation to discharge ink from the cap before starting recording. This configuration makes it possible to determine with high accuracy whether or not to perform an idle suction operation before starting recording. In particular, in cases where the idle suction operation requires the roll paper to be released from the nip or to be re-fed, as in the recording device configuration of this embodiment, downtime due to the idle suction operation is long. For this reason, it is necessary to accurately determine whether or not an idle suction operation is necessary.

[0046] Furthermore, the values ​​used in the calculation as fixed values ​​in this embodiment may be variable values ​​depending on the usage environment and print settings. For example, in this embodiment, a value assuming the maximum ink ejection volume v is used, but this value may be changed depending on the usage environment and the rank of the print head 717. By reflecting ideal values ​​that are closer to the actual environment in the calculation, the need for an empty suction operation can be determined with higher accuracy.

[0047] (Second embodiment) Next, a second embodiment of the present invention will be described. The transport drive configuration and the recovery mechanism configuration in this embodiment are the same as those in the first embodiment.

[0048] FIG. 11 is a flowchart of the recording operation in the present embodiment. The processing of this flowchart starts after receiving a recording command and after the paper feeding operation is completed. The processing related to the recording operation in the present embodiment is basically the same as that in FIG. 9. However, when it is determined that the need to execute the pre-recording air suction operation in step S903 is not required, if it is determined that the threshold value X is not exceeded, the process proceeds to step S1101. Then, by comparing with the threshold value Y, it is determined whether to execute the air suction operation after recording. If the threshold value Y is exceeded, after executing the recording operation in step S1102, the recording operation ends in step S1103. Then, in step S1104, after rewinding the recording medium to a predetermined position, the nip by the pinch roller is released. Thereby, the air suction operation can be executed. Then, in step S1105, the air suction operation is executed and the process ends. On the other hand, if it is determined in step S1101 that the threshold value Y is not exceeded, the recording operation is executed in step S907, and the recording operation ends in step S1106. At this time, the relationship between the threshold value X and the threshold value Y is Y < X < the cap capacity. The value of the threshold value Y can be, for example, a value obtained by subtracting the preliminary discharge amount to the cap before, during, and during standby in the recording mode, quality, and recording medium type with a high user usage frequency from the threshold value X. If the threshold value Y is set to an extremely small value, the frequency of the air suction operation after the end of recording will increase, and when continuously issuing the next recording command, it may reduce the user experience and increase the burden on the drive unit. Therefore, it is preferable to set an appropriate value from the above viewpoints.

[0049] As described above, a new threshold value Y is provided, and a case where the air suction operation is executed after the end of the recording operation is added. Thereby, when the next recording command comes, it is not necessary to execute the nip operation for feeding the recording medium again, and compared with the first embodiment described above, it is possible to further reduce the downtime.

[0050] In this embodiment, even when using the threshold Y to make a determination, the amount of preliminary ejection associated with the upcoming printing process is calculated. However, the dot count value during printing may be compared with the threshold Y to determine whether or not to perform idle suction after printing is completed. FIG. 12 shows a flow for determining whether or not to perform idle suction using the dot count value during printing. In this figure, the process up to the step S907 where the printing operation is performed is the same as that in FIG. 11. Even after the printing operation starts, the amount of ink M_3 currently ejected into the cap is counted (step S1201). This counting is performed when preliminary ejection is performed during printing between scans. Each time the dot count value M_3 is updated, a determination is made in step S1202 as to whether the ink amount M_3 exceeds the threshold Y. If the ink amount M_3 exceeds the threshold Y before the printing operation is completed, the idle suction operation and related operations from step S1102 to step S1105 are performed, as in the flow in FIG. 11. By comparing the measured value of the amount of ink actually ejected with the threshold value Y as shown in Figure 12, it is possible to reduce the number of cases in which it is determined that an empty suction operation is necessary, compared to when predicting the amount of preliminary ejection before printing assuming that the amount is at its maximum.

[0051] (Third embodiment) Next, a third embodiment will be described. The transport drive configuration and recovery mechanism configuration in this embodiment are the same as those in the first and second embodiments.

[0052] FIG. 13 is a flowchart of the printing operation in this embodiment. The process in this figure begins after a printing command is received and the paper feeding operation is completed. First, in step S1301, a cleaning flag determination sequence is executed. This is to perform the type of cleaning with the highest priority based on multiple determination results, such as the elapsed time since the previous cleaning was performed. Details of this will be explained later. Next, in step S1302, it is determined whether any cleaning flags have been set as a result of the determination in step S1301.

[0053] If any cleaning flag is set in step S1302, the process proceeds to step S1303, where the recording medium is rewound to a predetermined position, and then the nip by the pinch rollers is released. Then, in step S1304, the desired suction recovery operation is performed. After the suction recovery operation is performed, an empty suction operation is performed in step S1305, and the cleaning flag is turned OFF in step S1306. Then, in step S1307, the recording medium is fed, and the process ends.

[0054] On the other hand, if the cleaning flag is not set in step S1302, the process proceeds to the idle suction flag determination sequence in step S1308. This is a sequence for determining whether or not an idle suction operation needs to be performed, similar to the first and second embodiments described above. Details will be described later. In step S1309, it is determined whether or not the pre-recording idle suction flag is ON in the idle suction flag determination sequence in step S1308. If it is ON, the nip of the recording medium is released in step S904, and the idle suction operation is performed in step S905, just as in the case of performing the idle suction operation before recording in the first embodiment. After the idle suction operation is performed, the idle suction flag is changed to OFF. Then, in step S906, a cueing operation is performed to feed the recording medium again, and the process ends. On the other hand, if it is determined in step S1309 that the pre-recording idle suction flag is OFF, the process ends.

[0055] FIG. 14 is a diagram illustrating in detail the sequence for determining the cleaning flag in step S1301. In step S1401, the time t_1 elapsed since the previous cleaning is acquired. In step S1402, it is determined whether the time t_1 elapsed since the previous cleaning exceeds a threshold value t_th1. If it is determined that the threshold value t_th1 has been exceeded, cleaning flag A is turned ON in step S1403, and the process proceeds to step S1404. If it is determined that the threshold value t_th1 has not been exceeded, the process proceeds to step S1404, and the temperature T_h inside the head is acquired.

[0056] In step S1405, it is determined whether the temperature T_h inside the head exceeds the threshold value T_th. If it is determined that the temperature T_h has exceeded the threshold value T_th, the cleaning flag B is updated to ON in step S1406, and the process proceeds to step S1407. If it is determined that the temperature T_th has not exceeded the threshold value T_th, the process proceeds to step S1407, where the elapsed time t_2 from the time the last printer operation was completed is acquired.

[0057] In step S1408, it is determined whether the elapsed time t_2 exceeds the threshold value t_th2. If the threshold value t_th2 is exceeded, in step S1409, the cleaning flag C is updated to ON, and the process proceeds to step S1410. If the threshold value t_th2 is not exceeded, the process proceeds to step S1410, where the elapsed time t_3 from the last preliminary discharge time is acquired.

[0058] In step S1411, it is determined whether the elapsed time t_3 exceeds a threshold value t_th3. If it exceeds the threshold value t_th3, in step S1412, cleaning flag D is updated to ON, and the process proceeds to step S1413. If it does not exceed the threshold value t_th3, the process proceeds to step S1413, where it is determined whether any cleaning flags are ON. If at least one cleaning flag is ON, the process proceeds to step S1414, where the table in FIG. 19 is referenced to determine a cleaning operation with a high priority from among those whose cleaning flags are ON, and the flag is updated to ON, and the process ends. If it is determined in step S1413 that no cleaning flags are ON, the process ends.

[0059] FIG. 15 is a diagram for explaining in detail the sequence for determining the idle suction flag in step S1308. The processing in this figure is basically the same as the sequence shown in FIG. 11 of the second embodiment, but if threshold value X is exceeded in step S903, the pre-recording idle suction flag is turned ON in step S1501, and the processing ends. If threshold value X is not exceeded in step S903, the processing proceeds to step S1101, where it is determined whether threshold value Y is exceeded. If it is determined that threshold value Y is exceeded, the processing proceeds to step S1502, where the post-recording idle suction flag is updated to ON, and the processing ends. If it is determined that threshold value Y is not exceeded in step S1101, the processing ends as is.

[0060] FIG. 17 is a flowchart showing the operation of the recording device after recording ends. The process in this figure starts when recording ends. First, in step S1701, a post-recording cleaning flag determination sequence is executed. Details will be explained later using the figures. Next, in step S1702, it is determined whether any cleaning flags are ON as a result of the determination in step S1701. If at least one cleaning flag is ON, in step S1703, the recording medium is rewound to a predetermined position, the nip formed by the pinch roller is released, and in step S1704, a suction recovery operation is performed. After the suction recovery operation is performed, an empty suction operation is performed in step S1705, the cleaning flag is updated to OFF in step S1706, and the process ends. If the cleaning flag is not ON in step S1702, it is determined in step S1708 whether the post-recording empty suction flag is ON. If it is determined to be ON, the nip of the recording medium is released in step S1104, and an empty suction operation is performed in step S1105, as in the case of performing post-recording empty suction in the first embodiment. After the idle suction operation is performed, the post-recording idle suction flag is updated to OFF in step S1709, and the process ends. If it is determined in step S1708 that the pre-recording idle suction flag is OFF, the process ends.

[0061] FIG. 18 is a flowchart for explaining in detail the sequence for determining the post-printing cleaning flag in step S1701 in FIG. 17. In this embodiment, a function (hereinafter referred to as the dot count function) is provided to count and store the number of ink droplets ejected from the print head 717 during printing. Using this dot count function, a current dot count value D_1 is acquired in step S1801. In step S1802, it is determined whether the current dot count value D_1 exceeds a threshold value D_th1. If it does, a cleaning flag E is set ON in step S1803, and the process proceeds to step S1804. If it does not, the process proceeds to step S1804, where it is determined whether a pre-ejection stop flag is ON. In this embodiment, a function is provided to stop pre-ejection into the cap when a certain threshold value is exceeded to prevent ink from overflowing from the cap due to pre-ejection. If pre-ejection is stopped by this function, a pre-ejection stop flag is set ON. If the pre-ejection stop flag is not set ON, the process proceeds to step S1808. If the prefire stop flag is ON, the process proceeds to step S1805, where the elapsed time t_3 from the last prefire time is acquired. In step S1806, it is determined whether t_3 exceeds a threshold value t_th3, and in step S1807, cleaning flag D is set ON, and the process proceeds to step S1808. In step S1808, it is determined whether any cleaning flags have been set ON by the previous determinations. If any cleaning flags are ON, the process proceeds to step S1809, where the cleaning flag with the highest priority is determined by referring to the table in FIG. 19, and is set ON, and the process ends. If it is determined in step S1808 that no cleaning flags are set, the process ends.

[0062] As described above, before determining whether or not a cleaning operation is required, it is determined whether or not a cleaning operation is required due to different factors. This allows the necessity of the dry suction operation to be determined with high accuracy, enabling recording operations with reduced downtime.

[0063] In addition, in this embodiment, there are four cleaning flag determination conditions before recording and two cleaning flag determination conditions after recording, but depending on the product form, it is sufficient to set at least one cleaning determination condition before recording or after recording.

[0064] (Fourth embodiment) The transport drive configuration and the configuration of the recovery mechanism in this embodiment are the same as those in the first and second embodiments.

[0065] In this embodiment, the printer has a function (hereinafter referred to as "dot count") that counts and stores the amount of ink ejected from the head during printing. Using this dot count function, if the count value exceeds a certain threshold, a process called "dot count wiping" is performed, in which wiping is performed after page printing is completed. This process wipes the nozzle surface once and resets the amount of ink adhesion when the count value exceeds a certain threshold, in order to prevent minute ink droplets that have accumulated near the nozzles of the head from causing irregularities or defects in ink ejection and degrading image quality.

[0066] 20 is a flowchart showing the flag determination for dot count wiping execution. After page printing is completed, the dot count wiping flag determination sequence is started in step S2001, and the current dot count value is obtained in step S2002. In step S2003, it is determined whether this count value exceeds the threshold value D_th2. If it is determined in step S2003 that the count value does not exceed the threshold value D_th2, the sequence ends. If it is determined in step S2003 that the threshold value D_th2 is exceeded, the process proceeds to step S2004, where the wiping flag is updated to ON, and the sequence ends.

[0067] FIG. 22 is a flowchart of the overall suction recovery operation after printing, as in the third embodiment, including the dot count wiping flag determination sequence shown in FIG. 20. In step S1701, the post-printing cleaning flag determination sequence starts. If it is determined in step S1702 that the cleaning flag is ON, the operation is the same as in the third embodiment, except that wiping is performed in step S2207 after suction recovery in step S1704. If it is determined in step S1702 that the cleaning flag is not ON, the dot count wiping flag determination sequence is performed in step S2201, as shown in FIG. 20. Then, in step S2202, it is determined whether the dot count wiping flag is ON. If it is determined that the dot count wiping flag is ON, in step S2203, the transport roller 10 is rotated in the reverse direction from the state in which the roll paper 802 is nipped by the pinch roller 805, and the roll paper is rewound until the leading edge of the recording medium clears the sensor 804, and the pinch roller then releases the nip of the roll paper. After wiping the nozzles in step S2204, idle suction is performed in step S2205 regardless of the amount of ink in the cap, the wiping flag is turned OFF in step S2206, and the sequence ends. On the other hand, if it is determined in step S2202 that the wiping flag is not ON, the process proceeds to step S1708, where, as in the third embodiment, processing related to the post-printing idle suction flag is performed, and the sequence ends.

[0068] The nip release operation is also required when switching from using roll paper as the recording medium to feeding cut paper. Figure 21 is a flowchart of the recording medium replacement operation. The recording medium replacement sequence begins in step S2101. In step S2102, the roll paper 802 is nipped by the pinch rollers 805, and the transport rollers 10 are rotated in reverse to rewind the roll paper until the leading edge of the recording medium clears the sensor 804. The pinch rollers then release the roll paper from its nip, and in step S2103, an empty suction operation is performed regardless of the amount of ink in the cap. In step S2104, it is detected that the user has loaded a recording medium into the cut paper tray 809. Then, in step S2105, the paper feed operation begins, ending the sequence.

[0069] As described above, when the nip release operation of the recording medium becomes necessary due to a factor different from the execution determination sequence of the dry suction operation in the first to third embodiments, the dry suction operation is executed without predicting the preliminary ejection amount in the cap. This reduces the number of cases where unnecessary dry suction operations are performed after receiving a recording command, and makes it possible to perform recording operations with reduced downtime.

[0070] (Other embodiments) In order to realize one or more functions of the recording device or the host device in the above-described embodiments, the control unit 72 or the computer of the host device may execute a program. For example, the program may be provided to the recording device or the host device via a network or various storage media, and a computer (CPU, MPU, etc.) included in the recording device or the host device may read the program and execute the functions. Alternatively, the program may be executed by various elements. Furthermore, the program may be executed by one computer or by multiple computers working together.

[0071] In addition, it is not necessary to realize all of the processes in the above flowcharts by software, and some or all of the processes may be realized by hardware such as ASIC, etc. Furthermore, the present invention is not limited to a configuration in which all processes are performed by one CPU, and a configuration in which multiple CPUs appropriately cooperate to perform processes, or a configuration in which one CPU executes some processes and multiple CPUs cooperate to perform other processes. [Explanation of symbols]

[0072] 10 Conveyor roller 21 Motor 41, 42 Caps 802 roll paper 717 Recording head

Claims

1. a recording head provided with a plurality of nozzles for ejecting ink; a conveying means for conveying a recording medium relative to the recording head; a cap for receiving ink ejected from the recording head by preliminary ejection; a discharge means for performing a discharge operation to discharge the ink in the cap; an acquisition unit for acquiring, when a recording command is input to a recording medium, an ink amount after recording, which indicates the amount of ink in the cap at the time when recording in accordance with the recording command is completed; Equipped with an ink jet recording device, characterized in that the discharging means performs the discharging operation before starting recording in response to the recording command when the amount of ink after recording acquired by the acquiring means exceeds a threshold value;

2. 2. The inkjet recording apparatus according to claim 1, wherein the acquisition unit acquires a preliminary ejection amount during recording by preliminary ejection performed while recording is being performed in accordance with the recording command, and acquires the ink amount after recording based on the preliminary ejection amount during recording.

3. 3. The inkjet printing apparatus according to claim 2, wherein the acquisition unit acquires the preliminary ejection amount during printing based on the number of nozzles used in printing according to the printing command among the plurality of nozzles.

4. the recording in response to the recording command is a serial recording by scanning the recording head over the recording medium; 4. The inkjet recording apparatus according to claim 2, wherein the acquisition unit acquires the preliminary ejection amount during recording based on information indicating the number of times the recording head scans a predetermined unit area during recording in accordance with the recording command.

5. the recording in response to the recording command is a serial recording by scanning the recording head over the recording medium; 5. The inkjet printing apparatus according to claim 2, wherein the preliminary ejection during printing is performed during a period from the end of one scan of the print head to the start of the next scan in printing in response to the print command.

6. 6. The inkjet recording apparatus according to claim 1, wherein the acquisition unit acquires a preliminary ejection amount before recording due to a preliminary ejection performed before recording in accordance with the recording command, and acquires the ink amount after recording based on the preliminary ejection amount before recording.

7. 7. The inkjet printing apparatus according to claim 6, wherein the acquisition unit acquires the preliminary ejection amount before printing based on the number of nozzles used in printing according to the printing command.

8. 8. The inkjet recording apparatus according to claim 1, wherein the acquisition unit acquires a standby amount of preliminary ejection due to preliminary ejection performed during a predetermined standby time after recording in response to the recording command, and acquires the ink amount after recording based on the standby amount of preliminary ejection.

9. 9. The inkjet recording apparatus according to claim 1, wherein the acquisition unit acquires the amount of ink in the cap at the time the recording command is input, and acquires the amount of ink after recording based on the acquired amount of ink.

10. 10. The inkjet recording apparatus according to claim 1, wherein the conveying means and the discharging means are driven by a common driving source.

11. 11. The inkjet recording apparatus according to claim 1, wherein the discharging unit includes a pump that generates a negative pressure to perform the discharging operation.

12. 12. The inkjet recording apparatus according to claim 11, wherein the discharging means performs the discharging operation by driving the pump in a state where the recording head is not in contact with the cap.

13. The recording head is provided with a first nozzle row and a second nozzle row, 13. The inkjet recording apparatus according to claim 1, further comprising: a first cap for receiving ink ejected from the first nozzle row; and a second cap for receiving ink ejected from the second nozzle row.

14. 14. The inkjet recording apparatus according to claim 13, wherein the acquisition unit acquires the ink amount after recording for each of the first cap and the second cap.

15. a recording head provided with a plurality of nozzles for ejecting ink; a conveying means for conveying a recording medium relative to the recording head; a cap for receiving ink ejected from the recording head by preliminary ejection; a discharge means for performing a discharge operation to discharge the ink in the cap; A control method for an inkjet recording apparatus comprising: When a recording command is input to the recording medium, a post-recording ink amount is acquired, which indicates the ink amount in the cap at the time when recording in accordance with the recording command is completed; a control method, wherein the discharging unit executes the discharging operation before starting printing in response to the printing command when the acquired ink amount after printing exceeds a threshold value.

16. A program for causing a computer to execute the control method according to claim 15.

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