JP2023079173A - Ink jet printing device and control method - Google Patents

Abstract

To solve the problem of possible overflowing of ink from a cap when the amount of ink discharged by preliminary discharge exceeds a cap capacity.SOLUTION: When an amount of ink in a cap exceeds a threshold in a standby period after finish of a recording operation, standby preliminary discharge performed at certain time intervals is stopped and a recording device is placed in standby, thereby suppressing overflow of ink from the cap.SELECTED DRAWING: Figure 8

Description

The present invention relates to an inkjet recording apparatus and control method.

2. Description of the Related Art Conventionally, there is known an inkjet recording apparatus that records an image by applying ink onto a recording medium. In such an inkjet recording apparatus, the moisture in the ink evaporates from the nozzles (ejection ports) that eject the ink while the image is not being printed, and the viscosity increases, resulting in ejection failure of the ink from the nozzles. Sometimes. In order to suppress such ejection failures, so-called preliminary ejection is performed to eject ink that has increased viscosity in the nozzles toward the cap.

Japanese Patent Application Laid-Open No. 2002-200000 discloses that in order to reduce the amount of preliminary ejection during standby when no image is being printed, the environmental temperature is monitored and the timing and amount of preliminary ejection are varied depending on the environmental temperature. .

JP-A-2002-178533

Even if the amount of preliminary ejection is reduced as disclosed in Japanese Patent Application Laid-Open No. 2002-200013, it is not possible to perform preliminary ejection exceeding the capacity of the cap. If the amount of ink due to preliminary ejection exceeds the capacity of the cap, the ink may overflow from the cap and stain the inside of the device or the surroundings of the device.

In view of such problems, an object of the present invention is to suppress ink overflow due to the amount of ink in the cap due to preliminary ejection exceeding the capacity of the cap.

The present invention provides a recording head provided with a plurality of nozzles for ejecting ink onto a recording medium, a cap for receiving the ink ejected from the recording head by a preliminary ejection operation, and the preliminary ejection operation. storage means for storing the amount of ink ejected to the cap; and preliminary ejection during standby for performing the preliminary ejection operation at predetermined time intervals in a standby period after a recording operation for recording an image by the recording head is completed. Execution of the operation is started, and when the integrated value of the ink amount stored in the storage means does not exceed the threshold value, the standby preliminary discharge operation is continued, and the integrated value of the ink amount exceeds the threshold value. is exceeded, the standby preliminary ejection operation is stopped, and when the standby period exceeds a predetermined time, the recording head is brought into contact with the cap to end the standby period, and control means for controlling the recording head.

The present invention can suppress ink overflow due to the amount of ink in the cap due to preliminary ejection exceeding the capacity of the cap.

1 is a longitudinal sectional view showing the entire recording apparatus according to a first embodiment; FIG. 2 is a perspective view showing a driving mechanism of the printing apparatus shown in FIG. 1; FIG. FIG. 3 is a perspective view showing the configuration of a clutch gear shown in FIG. 2; 2 is a perspective view showing a recovery mechanism in the printing apparatus shown in FIG. 1; FIG. 2 is a perspective view showing a drive transmission configuration from a conveying roller to a pump mechanism in the printing apparatus shown in FIG. 1; FIG. FIG. 6 is a perspective view showing the pump mechanism shown in FIG. 5; 2 is a block diagram showing an outline of a control configuration of the printing apparatus shown in FIG. 1; FIG. 4 is a flowchart showing control of the printing apparatus according to the first embodiment; 4 is a flowchart showing control of the printing apparatus according to the first embodiment; 4 is a flowchart showing control of the printing apparatus according to the first embodiment; FIG. 2 is a vertical cross-sectional view showing the entire recording apparatus according to second and third embodiments; 10 is a flow chart showing control of a printing apparatus according to a third embodiment; 1 is a diagram showing the configuration of a print head; FIG. 9 is a flow chart showing control of the printing apparatus according to the second embodiment; 9 is a flow chart showing control of the printing apparatus according to the second embodiment; 10 is a flow chart showing control of a printing apparatus according to a fourth embodiment;

(First embodiment)
An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing the entire inkjet recording apparatus according to this embodiment. When a recording command is transmitted from a host device such as a PC, the control unit drives the motor 21 as a drive source for each mechanism. The motor 21 is illustrated in FIG. 2 described below. A motor 21 drives the paper feed mechanism 2 , the intermediate roller 6 , the transport roller 10 arranged downstream of the intermediate roller 6 , and the paper discharge roller 12 arranged downstream of the transport roller 10 .

The paper feed mechanism 2 pushes out the recording media P stacked on the paper feed tray 1 and abuts against the separation member 4 to separate them one by one. The separated recording medium P is conveyed by the paper feeding mechanism 2 to the intermediate roller 6 and the pinch roller 7 which is a pair thereof. When the leading edge of the recording medium P passes through the intermediate roller 6, it collides with the outer periphery of the U-turned paper guide, and the direction of transportation is reversed while following the paper guide, and reaches the transportation roller 10 and its paired pinch roller 11. do. When the leading edge of the recording medium P reaches the nip portion of the transport roller 10, the leading edge position is adjusted according to the type of the recording medium, and the skew of the recording medium is corrected. This tip position adjustment is also called tip registration. When the leading edge registration is performed, the transport roller 10 can also be rotated in the direction in which the recording medium P is returned, that is, in the reverse direction of the transport direction, by being driven by the motor 21 . On the other hand, the intermediate roller 6 is configured to always rotate in the forward direction in the conveying direction, that is, in the direction in which the recording medium P is ejected, regardless of which direction the motor 21 is driven. This two-roller configuration makes it possible to form a loop on the recording medium before the transport roller 10 . When the recording medium P reaches the conveying roller 10, the motor 21 reverses the driving direction, and once rotates the conveying roller 10 in the direction in which the recording medium P is rewound. Then, the conveying roller 10 is rotated again in the forward direction to convey the recording medium P in the discharge direction, thereby completing the leading edge registration. After the leading end registration is performed, the recording medium P is conveyed onto the platen, and the paper feeding operation is completed.

A printing unit 714 that scans in a direction crossing the direction in which the printing medium P is conveyed is arranged on the platen. The printing apparatus of this embodiment is a so-called serial printing type printing apparatus in which the printing unit 714 scans in a scanning direction (X direction in the figure) that intersects the conveying direction (Y direction in the figure). During this scanning, ink droplets are ejected from nozzles (ejection ports) of a print head 717 mounted on a printing unit 714 onto the print medium P transported over the platen, and the print medium P transported onto the platen is ejected. An image is recorded on the medium P (see FIG. 7 for the recording unit 714 and recording head 717).

FIG. 13 is a schematic diagram of the recording head 717. As shown in FIG. FIG. 13A is a conceptual diagram showing a nozzle surface (ejection port surface) on which a nozzle array in which a plurality of nozzles (ejection ports) that eject ink are arranged is arranged. FIG. 13(b) is a diagram showing the nozzle arrangement of each nozzle row. In each nozzle row, nozzles are arranged at intervals of 600 dpi in the Y direction in the drawing. Two nozzle rows for each ink color are arranged in a zigzag pattern with a shift of 1200 dpi in the Y direction. That is, the recording resolution in the Y direction for each ink color is 1200 dpi.

Note that the recording head 717 is provided with an ink flow path (not shown) for supplying ink to each nozzle. Also, inside each nozzle, a recording element is provided that generates energy for ejecting ink as droplets. In the present embodiment, an electrothermal conversion element that converts electrical energy into thermal energy is used as the recording element.

In FIG. 13A, rows a and b are nozzle rows in which nozzles for ejecting cyan ink are arranged, rows c and d are nozzle rows in which nozzles for ejecting magenta ink are arranged, rows e and f. is a nozzle array in which nozzles for ejecting yellow ink are arranged. Similarly, rows g and rows h are nozzle rows in which nozzles for ejecting black ink are arranged. 256 nozzles are arranged in each nozzle row corresponding to cyan, magenta, and yellow color inks, and 640 nozzles are arranged in the nozzle row corresponding to black ink.

A printing operation for printing an image is performed by repeating the transportation by the transportation roller 10 and the printing scanning by the printing unit 714 . In this embodiment, a so-called multi-pass printing method is performed in which printing of an image on a unit area is completed by scanning the unit area on the print medium a plurality of times. A printing scan by the printing unit 714 is also called a "pass", and the number of times the printing head 717 scans to complete printing on a predetermined unit area is called a "pass number". When the image recording is completed, the recording medium P is conveyed forward in the conveying direction by the pair of the discharge roller 12 and the spur 13 and discharged.

FIG. 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 for transmitting the driving force of the motor 21 to the transport roller 10 and the intermediate roller 6. As shown in FIG. In this embodiment, both the transport roller 10 and the intermediate roller 6 are commonly driven by the motor 21 . As a result, it is possible to reduce the size and cost of the main body of the recording apparatus.

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

3 is a perspective view showing the configuration of the clutch gear shown in FIG. 2. FIG. As shown in the figure, a spring 33 is provided inside the sun gear 31, and the forward rotation of the sun gear 31 tightens the spring 33, allowing the sun gears 31 and 32 to rotate together. On the other hand, the spring 33 opens when the sun gear 31 reverses. Therefore, when a load is applied to the sun gear 32, the sun gear 31 and the sun gear 32 slip and cannot rotate together. A swing arm 34 is provided on the axis of the sun gear 31 , and a planet gear 35 is attached on 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. A stage 38 of a multistage gear 37 is connected to the sun gear 32 . Further, the stage 39 of the multi-stage gear 37 is attached at a position where it can be connected to the planet gear 35 .

With these configurations, when the sun gear 31 rotates forward in the direction of arrow s, the drive input to the sun gear 31 is transmitted to the stage 38 of the multistage gear 37 by the sun gear 32 that rotates together with the sun gear 31 . On the other hand, when the sun gear 31 reverses in the direction of the arrow t, the swing arm 34 moves in the direction of the arrow u in the drawing, the planet gear 35 and the stage 39 of the multi-stage gear 37 are connected, and the drive is transmitted to the multi-stage gear 37. be done. Since the sun gear 32 is a clutch gear, it easily slips during reverse rotation and does not interfere with driving. With this transmission method, the direction of rotation of the multistage gear 37 is the same regardless of whether the sun gear 31 rotates forward or backward.

FIG. 4 is a perspective view showing the recovery mechanism 715. As shown in FIG. 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 motion of the recording head 717 in the reciprocating direction and can slide in an area outside the recording area where the image is recorded. Further, the slider 40 is movable in a direction perpendicular to the ejection port surface of the recording head 717 for the color ink and the ejection port surface for the black ink, that is, in the direction in which the ink is ejected. Such movement of the slider 40 enables the caps 41 and 42 to approach (contact) and separate from the discharge port surface of the recording head 717 .

The cap 41 is for cyan, magenta, and yellow color inks, and the cap 42 is for black ink. The slider 40 mounts a cap holder 44 and a cap holder 45 . In addition, according to the movement of the recording head 717, it is possible to move in the moving direction of the recording unit 714 and the direction in which the black and color recording heads 717 approach or separate from the cap in an area different from the recording area. . 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. By driving this suction pump, it is possible to perform a recovery operation of sucking ink from each ejection port through the cap.

FIG. 5 is a perspective view showing a drive transmission structure 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 interposed along the inner wall of the pump base 60 for half the circumference and are rotatably inserted within the pump base 60 . When the transport roller 10 is reversed by driving the motor 21 with the recording head 717 capped, driving force is transmitted to the pump roller holder 62 via the transport output gear 24 , the idler gear 25 and the pump drive gear 50 . A pump roller 64 moves a cam provided on the pump roller holder 62, and the inner wall of the pump base 60 and the pump roller 64 crush the pump tubes 51a and 51b. Further, when the reverse driving of the transport roller 10 is continued, a negative pressure is generated inside the pump tube.

When a negative pressure is generated in a state in which the ejection opening surface of the recording head 717 is capped by the caps 41 and 42 and is in close contact with them, ink can be sucked from the ejection openings of the recording head 717 via the caps 41 and 42 . On the other hand, if a negative pressure is generated in the capped state, a discharge operation (idle suction operation) for sucking and discharging ink accumulated in the cap due to preliminary ejection or the like can be executed. Further, in the idle suction operation, by crushing the pump tubes 51a and 52b, respectively, the caps 41 and 42 can be individually sucked with ink from the nozzles or the inside of the caps.

When the negative pressure inside the pump tube is released after the ink suction operation is finished, the pump roller holder 62 is driven to rotate in the opposite direction. That is, the conveying roller 10 is rotationally driven in the forward direction. By releasing the state in which the pump rollers 64 are crushing the pump tubes 51a and 51b, the negative pressure inside the pump tubes is released.

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 held in memories such as ROM and RAM. RAM is a volatile storage that temporarily holds programs and data. The ROM is non-volatile storage and holds table data and programs used in each process described later. As shown in FIG. 7, the control unit 72 outputs motor current control signals to the motor drivers 73 and 712 according to the input from the operation panel 71 or the connected PC 710, thereby controlling the following operations. .

A paper feed motor 74 corresponding to the motor 21 that drives the transport roller 10 and the like described above is driven by a signal input from the motor driver 73 to drive the paper feed/discharge feed roller via a transport drive transmission system 75 and a drive switching mechanism 77 . drive the unit 76; Also, the paper feed roller unit 78 and the intermediate roller unit 79 corresponding to the transport roller 10 and the intermediate roller 6 described above are similarly driven. Paper feed motor 74 drives the pump tube of the recovery mechanism described above.

Also, the recording unit motor 713 drives the recording unit 714 by a signal input from the motor driver 712 . Various sensors 711 provided in the paper conveying unit and the recording unit 714 detect the position of the recording medium P, the number of rotations of the conveying roller, the recording position of the recording unit, and the like. Appropriate control signals are output to the motor drivers 73 and 712 by inputting the detected signals to the control unit 72 .

The control unit 72 also drives the recording 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, as the preliminary ejection operation, pre-printing preliminary ejection performed before the printing operation for printing an image on the printing medium, preliminary ejection during printing performed during the printing operation, and the following print command are input. Preliminary discharge is performed during standby to prepare for a case where ink is ejected. These preliminary ejections are performed in order to eject ink that has thickened in the vicinity of the ejection openings, and in this embodiment, the ink is ejected onto the cap. Preliminary ejection of color ink is directed toward the cap 41 and black ink is directed toward the cap 42 .

FIG. 8 is a flow chart regarding the recording operation in this embodiment. “S” in each step below indicates “step”. This flow starts when a recording command is received. A cap opening operation is performed in S81, and the recording medium P is fed in S82. During the feeding operation of the recording medium P, in S83, a first pre-recording preliminary discharge (pre-recording preliminary discharge 1) is performed toward the caps 41 and . At S84, a recording operation for recording an image on the recording medium P is executed, and at S85 the recording operation is terminated. When the image printing operation is started, after the printing unit 714 finishes scanning and before starting the next scanning, preliminary ejection during printing is performed toward the cap. After the printing operation is finished, in S86, in preparation for receiving the next printing command, standby preliminary discharge is executed in the standby state with the cap open. This standby preliminary ejection is performed at predetermined time intervals. In this embodiment, the intervals are set to 2 seconds. By performing the standby preliminary ejection, even if there is a waiting time for the next reception command after printing the previous image, the ejection performance can be maintained for the next printing operation. .

The controller 72 counts the amount ejected toward the cap, that is, the number of ejected ink droplets, in each of the first preliminary ejection before recording in S83, the preliminary ejection during recording in S84, and the preliminary ejection during standby in S86. , the count result is stored in the RAM in the control unit 72 . In this embodiment, the count value is integrated, and the integrated value stored in the RAM is reset when the ink accumulated in the cap is discharged by the idle suction operation. In S87, the integrated value of the amount of ink stored in the cap is calculated and compared with the threshold value X stored in advance. The timing of the threshold comparison is immediately before the standby preliminary ejection in S86 is started and the preliminary ejection is performed at a predetermined time interval. If the integrated value is equal to or less than the threshold value X, the standby preliminary ejection of S86 is continued. On the other hand, if the integrated value exceeds the threshold value X, the process proceeds to S88 to stop standby preliminary ejection. That is, the setting is changed from the setting of performing preliminary ejection at regular time intervals to the setting of not performing preliminary ejection, and the print head 717 is made to wait on the cap. It should be noted that the integrated value of S87 and the threshold value X are periodically compared until the upper limit of the standby time described later or until the next recording command is received, and the integrated value does not exceed the threshold value. If so, the process of changing the standby preliminary ejection to stop in S88 is skipped.

Here, the threshold X is a value smaller than the cap capacity. Furthermore, even if the amount of ink in the second preliminary ejection before printing performed when the next printing command is received and the amount of ink in the preliminary ejection during printing are added, the value is less than the cap capacity. preferable.

After that, in S89, it waits until the next recording command is received. At S810, it is determined whether or not the standby time has exceeded a predetermined upper limit time. In this embodiment, A seconds=300 seconds. The reason why the upper limit of the standby time is set in this way is to maintain the ink ejection performance. If the waiting time with the cap open is too long, a large amount of ink must be sucked from the nozzles in order to recover the ink ejection performance before the next recording. If it is determined that the waiting time is within A seconds, the waiting state is continued. If it is determined that the time has exceeded A seconds, the standby state is terminated and the process advances to S816 to bring the cap into close contact with the recording head 717 and close it.

If the recording command is received while the standby time is within A seconds (S811), the standby state is terminated and the process proceeds to S812. In S812, a paper feeding operation is performed, in S813, preliminary ejection before printing is performed toward the cap in order to maintain ink ejection performance in the next printing operation, and then in S814, a printing operation is performed. .

Here, the conditions for pre-printing preliminary ejection in S813 differ depending on whether standby preliminary ejection is continued or stopped in the standby state. When a recording command is received without stopping standby preliminary ejection, the first pre-recording preliminary ejection (pre-recording preliminary ejection 1) is performed, and a recording command is received in a standby state with standby preliminary ejection stopped. If so, the second pre-recording preliminary discharge (pre-recording preliminary discharge 2) is performed. The second pre-recording preliminary ejection means that the ejection frequency is higher, the number of ink ejected is larger, or the ejection energy added in one ejection operation is larger than that of the first pre-recording preliminary ejection. is characteristic. The second pre-recording preliminary ejection corresponds to the fact that standby preliminary ejection has been stopped in S88, and is intended to improve the state in which the viscosity of the ink has increased due to the non-execution of standby preliminary ejection. With the goal. For this reason, the preliminary ejection conditions are determined so that a larger amount of ink is discharged than in the first pre-recording preliminary ejection.

In S815, the printing operation is terminated, and in S816, the cap is closed, and the series of processes is terminated.

As described above, in this embodiment, after the printing operation is finished, the standby preliminary ejection is performed at regular time intervals until the next printing command is received. At this time, standby preliminary ejection is stopped at the timing when it is determined that the amount of ink in the cap exceeds a predetermined threshold based on the capacity of the cap.

As a result, it is possible to prevent the ink from overflowing from the cap due to the continuation of preliminary ejection during standby. Also, when the next recording command is received, operations such as cap opening can be omitted, and downtime can be suppressed.

Also, as shown in FIG. 9, when the standby time after the end of printing exceeds A seconds, the process advances to S817 to perform an idle suction operation to discharge the ink accumulated in the cap due to the preliminary ejection. You may prepare. By executing the idle suction operation, it is possible to reset the integrated value in the RAM that indicates the amount of ink in the cap.

Further, as shown in FIG. 10, it may be determined whether or not the amount of ink accumulated in the cap is equal to or less than the threshold value Y after the end of printing. If it is determined to be equal to or less than the threshold Y, the process returns to the recording standby operation in S89, and if it is determined to exceed the threshold Y, the cap is closed in S816 after performing the idle suction operation in S817. At this time, the relationship between the threshold X and the threshold Y is X<Y<cap capacitance. By setting the threshold value Y in this way and comparing it with the amount of ink in the cap, it is possible to prolong the time until the idle suction operation or the cap closing operation is performed, thereby reducing the downtime.

In addition, although the cap is closed after the idle suction operation in FIGS. 9 and 10, it is also possible to perform only the idle suction operation.

(Second embodiment)
FIG. 11 is a cross-sectional view of an inkjet printing apparatus 1101 according to the second embodiment.

1102 is a 24-inch wide roll paper as a print medium, and 1103 is a holder for setting the roll paper. A sensor 1104 detects the presence or absence of a print medium, and a pinch roller 1105 for nipping the roll paper and a conveying roller 10 arranged to face the pinch roller 1105 . A conveying roller 1106 is arranged on the downstream side in the conveying direction, and a carriage 1107 on which the recording head 717 is mounted. A cutter 1108 cuts the roll paper after printing is completed. This drawing shows a state in which the roll paper 1102 is nipped by pinch rollers 1105 . The transport drive configuration and recovery mechanism configuration in this embodiment are the same as those in the first embodiment.

8 to 10, the roll paper 1102 is nipped from the standby preliminary discharge in S86 to the end of printing in S815 after the printing in S85. It is different in that it is a state. In this embodiment, a negative pressure is generated in the cap by reversing the conveying roller 10 . Therefore, it is necessary to release the nip of the roll paper 1102 in order to execute the cap closing operation for bringing the print head 717 into contact with the cap and the idle suction operation for discharging the ink in the cap. As shown in FIG. 11, when the roll paper 1102 is released from the nip, the leading edge of the roll paper is rewound to a position upstream of the sensor 1104 . In order to perform the recording operation again after releasing the nip, it takes time for nipping, so it is preferable to avoid releasing the nip as much as possible.

In the process of FIG. 8, the printing medium P is nipped even during the printing standby of S89, so that the paper feeding operation of S812 can be quickly executed after receiving the printing command of S811. The paper feeding operation here means the operation of conveying the print medium P from the nip position to an area where the print head 717 can print.

On the other hand, in this embodiment, when the roll paper 1102 is nipped, the caps 41 and 42 are kept separated from the ejection port surface of the print head 717 . As shown in FIG. 14, when the waiting time after the end of recording exceeds A seconds during the recording standby in S89, or after the recording in S815 ends, the process proceeds to S819, the nip is released, and the roll paper is released in S820. The roll paper is rewound until the leading edge reaches a position upstream of the sensor 1104, and in S817, the motor 21 is driven to perform an idle suction operation while keeping the cap away from the ejection port surface of the print head. After that, the cap is closed in S816.

Further, in this embodiment, as shown in FIG. 15, when it is determined in S87 that the integrated value of the amount of ink accumulated in the cap has exceeded the threshold value X during standby preliminary ejection in S86, preliminary ejection is stopped in S88. Proceeding to S819, the nip is released, and in S820, the roll paper is rewound until the leading edge of the roll paper reaches a position upstream of the sensor 1104. In S817, the motor 21 is driven to move the cap to the discharge port surface of the print head. Alternatively, the idle suction operation may be performed while the cap is separated from the cap, and the cap may be closed in S816.

As described above, similarly to the first embodiment, when the integrated value of the amount of ink stored in the cap reaches a predetermined threshold value with respect to the cap capacity, the roll paper is nipped and is in periodic standby. Change the setting so that prefire is not performed. As a result, ink overflow from the cap can be suppressed. Furthermore, in this embodiment, when the next print command is received, downtime can be suppressed by omitting the re-nipping operation due to paper feeding. In addition, by using a threshold value corresponding to the cap volume, the timing of performing the idle suction operation is delayed as much as possible, and the nip release and re-nipping operations required for performing the idle suction operation are reduced, thereby further reducing downtime. can be suppressed.

(Third embodiment)
The configuration of the inkjet recording apparatus in the third embodiment is the same as that in the second embodiment. FIG. 12 shows the flow of the recording operation in this embodiment. The processing up to the end of recording in S1205 is the same as in the second embodiment.

After the printing is completed, the roll paper 1102 is kept nipped and the caps 41 and 42 are kept separated from the ejection port surface of the printing head 717 in preparation for the next printing command. In S1206, the standby mode is determined. Here, the details of the standby mode will be described. Standby mode 1 is an inter-page delay mode, standby mode 2 is an eject cut mode, and standby mode 3 is a user cut mode.

The page-to-page delay in standby mode 1 assumes that the recorded matter cut by the cutter 1108 is dropped into a basket (not shown) or the like after the end of recording. In the case of a recording medium on which ink is difficult to fix, such as a film, the area where the image is recorded may be rubbed when the ink falls, resulting in image defects such as peeling off. In order to suppress the occurrence of such image defects, a predetermined weight is provided between the end of printing and the cutting by the cutter 1108 to improve the fixability of the ink. The user can arbitrarily set the wait time for the inter-page delay from the host device or main body UI (not shown).

Eject cut in standby mode 2 is a configuration in which the user determines the timing of cutting by the cutter 1108 after printing is finished. At the timing when the user wants to cut, an instruction to command the cutting operation is sent from the host device or the main body UI.

User cut in standby mode 3 is a mode in which the user manually cuts a print medium of a type that cannot be cut by the cutter 1108 . After the user cuts manually, the user inputs information indicating that the cutting has ended from the host device or the main body UI.

In any of the standby modes 1 to 3, standby time is required after the end of recording. For this reason, standby preliminary ejection is performed in preparation for the next recording command during standby. In S1206, it is determined whether or not any of the standby modes 1 to 3 is applicable, and in S1210, the largest threshold value Z among the applicable standby modes is set as the threshold value for the amount of ink in the cap. For example, standby mode 1: inter-page delay threshold Z1, standby mode 2: eject cut threshold Z2, standby mode 3: user cut threshold Z3, where Z1>Z2>Z3. Thereafter, in S1211, standby preliminary discharge is performed at predetermined intervals as described above. Next, in S1212, the integrated value of the amount of ink in the cap stored in the RAM is compared with a threshold value. If it is determined that the integrated value of the amount of ink in the cap is equal to or less than the threshold value Z, the process advances to S1211 to continue standby preliminary ejection. On the other hand, if it is determined that the integrated value of the amount of ink in the cap exceeds the threshold value Z, in S1213 the setting is changed so as to stop preliminary ejection during standby.

On the other hand, in the case of normal standby, which does not correspond to standby modes 1 to 3, the process advances to S1207 to set the threshold value of the amount of ink in the cap to X. After that, in S1208, standby preliminary ejection is performed at predetermined intervals, and in S1209, the integrated value of the amount of ink in the cap stored in the RAM and the threshold value X are compared. If it is determined that the integrated value of the amount of ink in the cap is equal to or less than the threshold value X, standby preliminary ejection is continued at predetermined intervals in S1208. On the other hand, if the integrated value of the amount of ink in the cap exceeds the threshold value X, the setting is changed so as to stop preliminary ejection during standby in S1213.

Here, the relationship between the threshold X and the threshold Z is Z<X. The reason for this is that standby modes 1 to 3 have a long standby time and the amount of ink due to preliminary ejection during standby to the cap increases, leading to ink overflow from the cap. In addition, the number of idle suction operations required to suppress ink overflow from the cap increases, leading to downtime. On the other hand, in the case of standby modes 1 to 3, it is preferable to change the setting so as to stop preliminary ejection during standby as soon as possible.

After the standby preliminary discharge is stopped, the printer waits for printing while nipping the roll paper (S1214). Then, in S1215, it is determined whether or not the standby time is within A seconds (300 seconds in this embodiment). If it is determined that the standby time has exceeded A seconds, the nip is released in S1225, an idle suction operation is performed in S1226, and the cap is closed in S1227. On the other hand, if the print command is received before the standby time exceeds A seconds (S1216), the paper feed operation is executed in S1217. After that, in S1218, it is determined whether or not the previous printing operation corresponds to the standby modes 1 to 3. If so, the process proceeds to S1219, and the second pre-printing preliminary ejection for maintaining the ejection performance at the time of the next printing is performed. to cap. After that, the recording operation is executed in S1221, and the recording ends in S1222. On the other hand, if the previous printing does not correspond to standby modes 1 to 3, in S1220, the third pre-printing preliminary ejection (pre-printing preliminary ejection 3) is performed toward the cap. Thereafter, recording is executed in S1221, and recording ends in S1222. The relationship of the pre-printing preliminary ejection is the following relationship in the ejection frequency, the number of ejections, or the ejection energy.
1st preliminary ejection before recording < 2nd preliminary ejection before recording < 3rd preliminary ejection before recording This is because the degree of viscosity increase of the surrounding ink is increased.

After printing is completed, it is determined whether the amount of ink in the cap exceeds the threshold value X, and if it is determined that it is equal to or less than the threshold value, the process returns to the standby mode determination in S1206. If it is determined that the threshold value X is exceeded, the process advances to S1224 to determine whether the ink amount in the cap exceeds the threshold value Y or not. If it is determined that the amount of ink in the cap is equal to or less than the threshold value Y, the process returns to print standby in S1214. If it is determined that the amount of ink in the cap exceeds the threshold value Y, the LF nip is released in S1225, the roll paper 1102 is returned to the position where the leading edge of the roll paper 1102 has passed the sensor 1104, and standby. Thereafter, in S1226, an idle suction operation is performed by rotating the conveying roller 10 while keeping the cap away from the ejection port surface of the recording head 717, and in S1227, the cap is closed.

As described above, in the present embodiment, it is possible to appropriately set the threshold used for comparison with the amount of ink in the cap by determining which one of standby modes 1 to 3 is in effect.

(Fourth embodiment)
In the first to third embodiments, the integrated value of the amount of ink preliminarily ejected into the cap is compared with the threshold value X, and if it is larger than the threshold value, preliminary ejection is stopped during standby. In the mode, as shown in FIG. 16, the amount or interval of standby preliminary ejection is changed when the integrated value exceeds the first threshold, and the standby preliminary ejection is stopped when the second threshold is exceeded. can be FIG. 16 is a diagram in which the flow chart up to recording standby in FIGS. 8 to 10 is replaced with this embodiment. After the recording in S85, standby preliminary ejection 1 is performed in S86. In standby preliminary ejection 1, eight preliminary ejections are performed for each nozzle at intervals of 2 seconds. In S821, the integrated value of the amount of ink stored in the cap before the standby preliminary ejection 1 is performed is calculated and compared with the threshold value X1. If it is equal to or less than the threshold value X1, standby preliminary ejection 1 of S86 is continued. On the other hand, if the integrated value exceeds the threshold value X1, the process advances to S822 to execute preliminary ejection 2 during standby. Here, standby preliminary ejection 2 is characterized in that the preliminary ejection interval is longer or the number of preliminary ejections from each nozzle is smaller than that of standby preliminary ejection 1 . Specifically, standby preliminary ejection 2 is preliminary ejection of eight shots from each nozzle at intervals of four seconds, or preliminary ejection of four shots from each nozzle at intervals of two seconds. Next, in S87, the integrated value of the amount of ink stored in the cap is calculated and compared with the threshold X. If it is equal to or less than the threshold value X, standby preliminary discharge 2 of S822 is continued. On the other hand, if the integrated value exceeds X, the process advances to S88 to stop preliminary ejection during standby, and to wait for recording in S89. The threshold X1 is a numerical value smaller than the threshold X here.

Subsequent steps are the same as in the first to third embodiments.

As described above, in the present embodiment, when the integrated value of the amount of preliminary ejected ink ejected into the cap exceeds the first threshold value, the standby preliminary ejection interval is lengthened or the preliminary ejection is not performed. By reducing the number of shots, the time until the cap overflows can be lengthened, and when the integrated value exceeds the second threshold value, preliminary ejection during standby is stopped to suppress the cap overflow. be able to.

The present disclosure includes configurations typified by the following printing apparatus examples and printing apparatus control method examples.

10 Transport Roller 21 Motor 41, 42 Cap 1102 Roll Paper 717 Recording Head

Claims (18)

a recording head provided with a plurality of nozzles for ejecting ink onto a recording medium;
a cap for receiving ink ejected from the recording head by a preliminary ejection operation;
storage means for storing the amount of ink ejected onto the cap by the preliminary ejection operation;
During a standby period after the recording operation for recording an image by the recording head is finished, execution of the standby preliminary ejection operation for performing the preliminary ejection operation at predetermined time intervals is started, and the ink stored in the storage means is started. If the integrated value of the ink amount does not exceed the threshold value, the standby preliminary ejection operation is continued, and if the integrated value of the ink amount exceeds the threshold value, the standby preliminary ejection operation is stopped. and control means for controlling the recording head such that, when the standby period exceeds a predetermined time, the recording head is brought into contact with the cap to end the standby period. Inkjet recording device. 2. The ink jet printing apparatus according to claim 1, wherein said control means terminates the waiting period when receiving a print command relating to the next printing operation during the waiting period. A motor for driving a transport motor and a carriage for moving the recording head is further provided, and the standby preliminary discharge operation is started when the transport motor and the motor for driving the carriage are not driven for a predetermined time. The inkjet recording apparatus according to claim 1, characterized by: 2. An inkjet recording apparatus according to claim 1, further comprising discharging means for discharging ink in said cap while said recording head is not in contact with said cap. 5. An inkjet recording apparatus according to claim 4, wherein said discharging means performs said discharging operation when said standby period exceeds a predetermined time. 5. An ink jet recording apparatus according to claim 4, wherein said storage means resets said integrated value stored when said discharging operation is performed by said discharging means. 2. The control means controls the printhead so as to execute a pre-printing preliminary ejection operation for ejecting ink onto the cap before starting a printing operation subsequent to the printing operation. 3. The inkjet recording apparatus according to . The control means performs a first pre-recording preliminary ejection operation when receiving a recording command after continuing the preliminary ejection operation during standby, and issues a recording command after stopping the preliminary ejection operation during standby. 8. An ink jet recording apparatus according to claim 7, wherein when receiving the second pre-recording preliminary ejection operation, a second pre-recording preliminary ejection operation with a larger amount of ink than the first pre-recording preliminary ejection operation is executed. 2. An ink jet recording apparatus according to claim 1, wherein said control means controls said recording head so as to perform a preliminary discharge operation during recording in which ink is discharged to said cap during said recording operation. further comprising a transport roller for transporting the recording medium and means for nipping the recording medium facing the transport roller;
The recording medium is roll paper,
2. An inkjet recording apparatus according to claim 1, wherein said standby preliminary ejection operation is performed in a state in which said recording medium is nipped. further comprising a motor as a drive source for nipping the recording medium;
11. An ink jet recording apparatus according to claim 10, wherein said motor is a drive source for discharging ink from said cap while said recording head is not in contact with said cap. further comprising determination means for determining whether the standby state is one of normal standby, inter-page delay, eject cut, and user cut after the end of the recording operation;
2. An inkjet recording apparatus according to claim 1, wherein said threshold value is changed based on a result of determination by said determination means. 13. The inkjet recording apparatus according to claim 12, wherein the threshold value is smaller in inter-page delay, eject cut, and user cut than in normal standby. a recording head provided with a plurality of nozzles for ejecting ink onto a recording medium;
a cap for receiving ink ejected from the recording head by a preliminary ejection operation;
storage means for storing the amount of ink ejected onto the cap by the preliminary ejection operation;
During a standby period after the recording operation for recording an image by the recording head is finished, execution of the standby preliminary ejection operation for performing the preliminary ejection operation at predetermined time intervals is started, and the ink stored in the storage means is started. and control means for controlling the recording head so that the time interval of the standby preliminary ejection operation is lengthened when the integrated value of the amount exceeds a first threshold value. a recording head provided with a plurality of nozzles for ejecting ink onto a recording medium;
a cap for receiving ink ejected from the recording head by a preliminary ejection operation;
storage means for storing the amount of ink ejected onto the cap by the preliminary ejection operation;
During a standby period after the recording operation for recording an image by the recording head is finished, execution of the standby preliminary ejection operation for performing the preliminary ejection operation at predetermined time intervals is started, and the ink stored in the storage means is started. and control means for controlling the recording head so that the number of ejections in the standby preliminary ejection operation is reduced when the integrated value of the amount exceeds a first threshold value. During a standby period after the printing operation for printing an image by a print head provided with a plurality of nozzles for ejecting ink onto a printing medium is completed, a preliminary ejection operation for ejecting ink onto the cap is performed at predetermined time intervals. start execution of the standby preliminary discharge operation performed in ,
if the integrated value of the amount of ink ejected onto the cap by the preliminary ejection operation stored in the storage means does not exceed a threshold value, the standby preliminary ejection operation is continued;
when the integrated value exceeds the threshold value, stopping the standby preliminary ejection operation;
and controlling the recording head to terminate the standby period by bringing the recording head into contact with the cap when the standby period exceeds a predetermined time. During a standby period after the printing operation for printing an image by a print head provided with a plurality of nozzles for ejecting ink onto a printing medium is completed, a preliminary ejection operation for ejecting ink onto the cap is performed at predetermined time intervals. start execution of the standby preliminary discharge operation performed in ,
A method comprising: controlling the recording head such that a time interval of the standby preliminary ejection operation is lengthened when an integrated value of the amount of ink ejected into the cap exceeds a threshold value. During a standby period after the printing operation for printing an image by a print head provided with a plurality of nozzles for ejecting ink onto a printing medium is completed, a preliminary ejection operation for ejecting ink onto the cap is performed at predetermined time intervals. start execution of the standby preliminary discharge operation performed in ,
A method comprising: controlling the recording head so as to reduce the number of ejections in the standby preliminary ejection operation when an integrated value of the amount of ink ejected into the cap exceeds a threshold value.

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