JP6256091B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus that performs a flushing operation for ejecting droplets from a print head at a position outside a scanning region during printing of the print head.

  In this type of printing apparatus, printing is performed on a print medium such as fed paper by a print head. For example, in a serial type printing apparatus, the print head moves in the scanning direction together with the carriage, and prints an image or the like by ejecting ink onto the surface of the paper during the movement.

  Further, before the ink is ejected onto the print medium, the carriage moves to a predetermined position outside the transport area of the print medium to discharge the ink in order to prevent clogging due to thickening of the ink in the nozzle of the print head. A printing apparatus that performs a flushing operation is known (for example, Patent Document 1). In this printing apparatus, a paper feed confirmation operation for feeding a predetermined amount of print medium and detecting the success or failure of paper feed is performed, and at least a part of the flushing operation is performed simultaneously with the paper feed confirmation operation.

  In Patent Document 1, since at least a part of the sheet feeding confirmation operation and the flushing operation performed as one of the feeding operations is performed at the same time, there is no period during which the sheet feeding confirmation operation and the flushing operation are performed at the same time. Compared to the configuration, the feeding of the printing medium can be completed earlier, and the ejection of ink onto the printing medium can be started earlier, and the printing throughput can be improved.

  When the feeding operation includes a plurality of operations as described above, it is preferable to perform the flushing operation and one of the plurality of operations constituting the feeding operation by overlapping at least a part of the operation timing. The operations constituting the feeding operation include a skew removal operation (alignment operation) performed in the middle of the feeding operation in order to remove skew (skew) in which the print medium is fed obliquely with respect to the transport direction, There is a cueing operation for transporting the print medium to the print start position. For example, in the skew removal operation, the leading end of the printing medium to be fed is brought into contact with the reverse rotation abutting method in which the leading end of the printing medium is reversed, or the front end of the sheet is held in a state in which the leading end of the paper projects to the downstream side in the conveying direction. After the biting operation to be performed, there is a biting discharge method that removes the skew by reversing the conveyance roller pair and discharging the leading end portion of the print medium to the upstream side in the conveyance direction.

JP-A-8-37006

  By the way, in the page switching period in which the previous page is discharged and the next page is fed after printing, at least one of the plurality of operations and the operation timing of the plurality of operations constituting the feeding operation of the next page is performed. It is preferable that a part is overlapped from the viewpoint that printing of the next page can be started at an early stage.

  In Patent Document 1, one operation (paper feeding confirmation operation) that overlaps at least a part of the flushing operation and the operation timing among a plurality of operations included in the feeding operation is determined in advance. For this reason, depending on the combination of the length of the operation time of the flushing operation and the operation time of the one operation, the flushing operation may not be completed even after the completion of the one operation. In this case, according to the sequence, the next operation is started after the end of the flushing operation. The delay in the start time of the next operation due to this wait time delays the start time of printing on the next page. This may cause a decrease in printing throughput.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to superimpose at least a part of the operation timing of one of a plurality of operations included in the feeding operation and the flushing operation. In this case, it is an object of the present invention to provide a printing apparatus that can reduce the delay of the start time of the next operation that is started after the flushing operation.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A printing apparatus that solves the above problems includes a print head that performs printing by moving relative to a print medium and ejecting droplets onto the print medium, and a conveyance direction of the print medium relative to the print head An alignment operation that includes at least one operation of aligning the print medium with respect to the conveyance roller pair, and an alignment operation that includes a conveyance roller pair that is disposed upstream and conveys the print medium to the print head; A transport unit that performs a feeding operation including a cueing operation that transports a print medium to a print start position, a control unit that controls the print head and the transport unit, and printing of the print head A droplet receiving portion that receives the droplets disposed outside the scanning region at the time, and the control unit stops the print head against the droplet receiving portion to drop the droplets. When performing the flushing operation to be performed, the flushing is performed by superimposing at least a part of the operation timing on one of the plurality of operations within a period from the stop of the print head to the resumption of movement. When an operation is performed, one operation that minimizes the delay in the start timing of the next operation that is started after the end of the flushing operation is predicted, and at least a part of the operation timing is assigned to the predicted one operation. The flushing operation is performed by superimposing them. Note that “the least delay in the start timing of the next operation” is not limited to a configuration in which, for example, a value indicating the degree of delay such as a delay time is compared and one operation having the smallest value is selected. . For example, when comparing a value indicating the degree of delay, an allowable range (allowable value) is set, and if the difference between two values indicating the degree of delay exceeds the allowable range, one operation that minimizes the delay is selected. It is a concept including the structure made. In this case, when the difference between the two values does not exceed the allowable range, the concept that the second operation with the smallest delay may be selected, for example.

  According to this configuration, the control unit performs the following process when performing the flushing operation for stopping the print head to face the droplet receiving unit and discharging the droplets. When the flushing operation is performed by superimposing at least a part of the operation time on one of a plurality of operations constituting the feeding operation within a period from when the print head is stopped to when the movement is resumed. One operation that minimizes the delay in the start time of the next operation that is performed after the end of the flushing operation is predicted. Then, the flushing operation is performed by superimposing at least a part of the operation time on the predicted one operation. Therefore, the next operation that is started after the flushing operation is compared with a configuration in which at least a part of the operation time is overlapped with one predetermined operation among a plurality of operations constituting the feeding operation, and the flushing operation is performed. It is possible to reduce the delay of the start time. For example, the printing throughput of the printing apparatus can be improved.

  In the printing apparatus, when the controller performs the flushing operation by superimposing at least a part of the operation timing on one of the plurality of operations, both the one operation and the flushing operation are performed. Predicting the delay time of the start timing of the next operation that is started after waiting for the end of each of the plurality of operations, and predicting the operation satisfying the condition that the delay time is the shortest as the one operation. preferable.

  According to this configuration, when the flushing operation is performed by superimposing at least a part of the operation timing on one of the plurality of operations, the operation is started after both the one operation and the flushing operation are finished. A delay time of the start time of the next operation is predicted for each of the plurality of operations. Then, an operation that satisfies the condition that the predicted delay time is the shortest is predicted as one operation to be overlapped with the flushing operation. Therefore, printing by the print head on the printing medium fed by the feeding operation can be started at an early stage.

  In the printing apparatus, when the controller performs the flushing operation by superimposing at least a part of the operation timing on one of the plurality of operations, both the one operation and the flushing operation are performed. The delay time of the start timing of the next operation that is started after the end of the operation is predicted for each of the plurality of operations, and the operation that satisfies the shortest condition under the given delay time is given to the one operation. It is preferable to predict as one operation.

  According to this configuration, when the flushing operation is performed by superimposing at least a part of the operation timing on one of the plurality of operations, the operation is started after both the one operation and the flushing operation are finished. The delay time of the start time of the next operation is predicted for each of the plurality of operations, and the operation that satisfies the shortest condition after giving the allowable delay time is one of the objects to be overlapped with the flushing operation. Expected as behavior. Therefore, printing by the print head on the printing medium fed by the feeding operation can be started at an early stage.

  In the printing apparatus, the control unit predicts the required time of each of the plurality of operations, and superimposes at least a part of the operation time on one operation that satisfies the condition that the predicted required time is the longest. It is preferable to perform a flushing operation.

  According to this configuration, one operation having the longest required time is selected from the plurality of operations constituting the feeding operation, and the flushing operation is performed by superimposing at least a part of the operation timing on the one operation. . Therefore, it is possible to ensure a long overlapping period between the flushing operation and one operation and to start printing on the print medium after the flushing operation by the print head at an early stage.

  In the printing apparatus, when there are two or more operations that satisfy the condition, the control unit preferably determines one operation according to a set priority order among the two or more operations.

  According to this configuration, when there are two or more operations that satisfy the condition, one operation is determined according to the set priority order among the two or more operations. Then, the flushing operation is performed by superimposing at least a part of the operation time on the determined one operation. Therefore, one more appropriate operation according to the priority order can be determined as a superimposition target of the flushing operation.

  In the printing apparatus, the alignment operation includes a biting operation in which the conveyance roller pair bites into a state in which a front end portion of the printing medium protrudes downstream in the conveyance direction of the conveyance roller pair, and the biting tip. It is preferable to include a discharge operation for discharging the portion to the upstream side in the transport direction.

  According to this configuration, the flushing operation is performed by superimposing at least a part of the operation timing on one operation that requires the least delay among the biting operation, the discharge operation, and the cueing operation. Therefore, the delay of the next operation that is started after the end of both one operation and the flushing operation can be minimized.

  In the printing apparatus, the alignment operation includes an abutting operation that abuts the leading end of the print medium on the downstream side in the conveyance direction, and the leading end of the printing medium abuts on the conveyance roller pair by the abutting operation. In this case, it is preferable to include a reverse rotation operation for reversing the transport roller pair in a rotation direction in which the print medium can be transported upstream in the transport direction.

  According to this configuration, the flushing operation is performed by superimposing at least a part of the operation time on one operation that requires the least delay among the butting operation, the reverse rotation operation, and the cueing operation. Therefore, the delay of the next operation that is started after the end of both one operation and the flushing operation can be minimized.

  In the printing apparatus, it is preferable that the flushing operation is stopped when the one operation in which at least a part of the flushing operation and the operation timing are overlapped is started.

  According to this configuration, even if the operation of the transport unit can be commanded only when the flushing operation is stopped, the flushing operation is stopped when starting one operation, so one operation is started. From this, the flushing operation can be started. Therefore, the flushing operation can be performed by superimposing at least a part of the operation time on one operation.

  In the printing apparatus, the control unit is configured to perform an operation that has already started at a stop point when the print head that has finished printing on the print medium has moved to a position facing the droplet receiving unit. It is preferable that the flushing operation is started from the stop time, and for the operation that has not been started at the stop time, the flushing operation is started after the start of the operation.

  According to this configuration, for the operation that has already started at the stop point when the print head that has finished printing on the print medium has moved to a position facing the droplet receiving portion and stopped, the flushing operation is started from the stop point. Is started. On the other hand, for an operation that has not been started at the time of stopping, the flushing operation is started after the start of the operation. Therefore, it is possible to ensure a long period in which the operation timing of the flushing operation and one operation can be overlapped.

In the printing apparatus, it is preferable that the scanning operation of the print head after the flushing operation is started before the end of the cueing operation.
According to this configuration, the scanning operation of the print head after the flushing operation is started before the end of the cueing operation. Thereby, the scanning operation of the print head is performed by superimposing at least a part of the operation time on the cueing operation. Therefore, printing by the print head on the printing medium conveyed by the cueing operation can be started at an early stage. For example, it can contribute to an improvement in printing throughput.

  In the printing apparatus, it is preferable that at least the time required for the flushing operation is variable among the time required for the plurality of operations constituting the flushing operation and the feeding operation.

  According to this configuration, since at least the time required for the flushing operation is variable among the time required for the plurality of operations constituting the flushing operation and the feeding operation, even if the time required for the flushing operation varies for each print medium. The flushing operation for each print medium can be performed by superimposing at least a part of the operation time on one appropriate operation.

1 is a schematic side sectional view showing a printer according to an embodiment. The principal part schematic front view of a printer. The principal part schematic plan view of a printer. FIG. 3 is a schematic bottom view showing a print head and ejection elements. FIG. 3 is a block diagram illustrating an electrical configuration of the printer. The block diagram which shows the function structure of a computer. It is a model side view explaining the skew removal operation | movement of a biting discharge system, (a) shows initial biting operation | movement, (b) shows skew removal operation | movement, (c) shows cueing operation | movement, respectively. It is a model side view explaining the skew removal operation | movement of a reverse rotation abutting method, (a) shows reverse rotation abutting operation | movement and (b) shows cueing operation | movement, respectively. The model side view explaining interpage control. 6 is a timing chart for explaining the skew removal operation of the biting discharge method. The timing chart explaining the skew removal operation | movement of a reverse butting method. FIG. 6 is a schematic plan view illustrating a flushing operation during printing. The timing chart explaining regular flushing operation | movement. The timing chart when superimposing regular flushing on the initial biting operation in the biting discharge method. Timing chart when periodic flushing is superimposed on skew removal operation in the crevice discharge method. Timing chart when periodic flushing is superimposed on cueing operation in the crevice discharge method. The timing chart when the regular flushing is overlapped with the skew removal operation from the middle in the biting discharge method. The timing chart at the time of superimposing a regular flushing on a butting operation in the reverse butting method. A timing chart when periodic flushing is superimposed on a skew removal operation (reverse operation) in the reverse contact method. A timing chart when periodic flushing is superimposed on the cueing operation in the reverse contact method. The flowchart explaining the control program of flushing between pages. Same flowchart. Same flowchart.

Hereinafter, an embodiment in which a printing apparatus is embodied as a serial printer will be described with reference to the drawings.
A printer 11 illustrated in FIG. 1 is an ink jet printer that prints a document, an image, or the like by attaching ink, which is an example of a liquid, to a sheet, which is an example of a printing medium.

  As shown in FIG. 1, the printer 11 includes an apparatus main body 12 and one or a plurality of feeding apparatuses 13 (one in the example of FIG. 1) detachably added to the lower side of the apparatus main body 12. Prepare. When the number of expansions is plural, the feeding device 13 is stacked in a plurality of stages along the vertical direction.

  A feeding unit 15 (automatic sheet feeder) capable of automatically feeding the paper 14 is provided at the rear portion (right end portion in FIG. 1) of the apparatus main body 12. On the other hand, a discharge unit 16 for discharging the printed paper 14 is provided at the front portion (left end portion in FIG. 1) of the apparatus main body 12. The feeding unit 15 includes a tray 15a on which the paper 14 is set, a hopper 15b, and a feeding roller 15c. The paper 14 pressed against the feeding roller 15c by the operation of the hopper 15b is transported by the rotation of the feeding roller 15c. It is sent out toward the pair 17.

  In the apparatus main body 12, conveyance roller pairs 17 and 18 and discharge roller pairs 19 and 20 that convey the paper 14 from the feeding unit 15 toward the discharge unit 16 are arranged along the conveyance path. A printing unit 21 that prints an image or the like on the paper 14 is disposed at a position between the transport roller pair 18 and the discharge roller pair 19.

  The printing unit 21 is arranged at an upper position facing the conveyance path of the portion between the conveyance roller pair 18 and the discharge roller pair 19 and is orthogonal to the conveyance direction Y (in the direction orthogonal to the paper surface in FIG. 1). And a print head 26 provided at the bottom of the carriage 25. Above the printing unit 21, a mounting unit 28 (holder) on which a container 27 that stores ink is detachably mounted is disposed. Further, the printing unit 21 includes a support base 29 that supports the paper 14 at a lower position facing the moving area of the print head 26. The print head 26 ejects the ink supplied from the container 27 through the tube 28 </ b> A onto a portion of the paper 14 supported by the support base 29, whereby an image or the like is printed on the paper 14.

  At the bottom of the apparatus main body 12, there are a cassette 31 in which a plurality of sheets 14 are stored in a stacked state, and a supply unit 32 that sends the sheets 14 stored in the cassette 31 one by one to the feeding path toward the printing unit 21. Is provided.

  The supply unit 32 includes a pickup roller 33 that contacts the uppermost sheet among the plurality of sheets 14 in the cassette 31, a separation roller 34, and a retard roller 35 that forms a pair with the separation roller 34. The supply unit 32 includes an intermediate roller 36 disposed behind the pair of transport rollers 17 and two driven rollers 37 and 38 that sandwich the paper 14 between the intermediate roller 36. The transport roller pair 17 includes an intermediate roller 17A that is rotationally driven in conjunction with the intermediate roller 36, and a driven roller 17B that makes a pair with the intermediate roller 17A.

  When the pickup roller 33, the separation roller 34, and the intermediate rollers 36 and 17A are rotated counterclockwise in FIG. 1 by the power of the feeding motor 67 (see FIG. 5) provided in the apparatus main body 12, the cassette 31 accommodates them. The sheets 14 thus fed are fed one by one to the printing unit 21 via the transport roller pairs 17 and 18. A feeding path 39 that is a path for the sheet 14 sent out from the added feeding device 13 is formed to extend upward from the bottom of the apparatus main body 12.

  The feeding device 13 includes a cassette 41 that can store a plurality of sheets 14 in a stacked state, a feeding mechanism 40 that feeds the sheets 14 stored in the cassette 41 one by one, and a sheet 14 that the feeding mechanism 40 sends out. A conveyance mechanism 42 that conveys, and a power source 48 that drives the feeding mechanism 40 and the conveyance mechanism 42 are provided.

  The feeding mechanism 40 includes a pickup roller 43 that contacts the uppermost sheet 14 in the cassette 41, a feeding roller 44 that feeds the sheet 14 toward the transport mechanism 42, and a retard roller 45 that makes a pair with the feeding roller 44. With. The transport mechanism 42 includes a transport roller 46 and a driven roller 47 that makes a pair with the transport roller 46.

  The power source 48 is, for example, a DC motor capable of forward and reverse rotation. Further, the feeding device 13 includes a power transmission mechanism 49 for transmitting the power of the power source 48 to the pickup roller 43, the feeding roller 44 and the transport roller 46. The power source 48 and the power transmission mechanism 49 are disposed on the side of the cassette 41 (in FIG. 1, on the front side of the cassette 41).

  When the power source 48 is rotationally driven and the pickup roller 43, the feeding roller 44, and the transport roller 46 are rotated counterclockwise in FIG. 1, the sheets 14 stored in the cassette 41 are fed one by one to the apparatus main body 12. The paper is fed toward the sending path 39. The retard roller 45 has a function of separating the uppermost paper 14 from the lower paper group when the pickup roller 43 sends out a plurality of papers 14. Further, below the feeding roller 46 and the driven roller 47, when a lower feeding device is further added below the feeding device 13, the path of the paper 14 fed from the lower feeding device 13 is passed. The feeding path 50 is formed so as to extend upward from the bottom of the feeding device 13.

  As shown in FIG. 2, the carriage 25 constituting the printing unit 21 in the printer 11 is guided by a guide shaft 51 so as to be reciprocable in the scanning direction X, and extends along the scanning direction X on the back side thereof. It is fixed to a part of the endless timing belt 52 stretched in this manner. The carriage 25 reciprocates in the scanning direction X along the guide shaft 51 when the timing belt 52 rotates forward or backward by the power of the carriage motor 53.

  As shown in FIGS. 2 and 3, the paper 14 conveyed to the printing unit 21 is supported by a plurality of ribs 29 a protruding on the support base 29, so that the space between the paper 14 and the print head 26 is obtained. An appropriate interval (gap) is secured.

  2 and 3, the right end portion of the carriage 25 on the movement path in FIG. 2 and FIG. 3 is a home position HP (home position) where the carriage 25 stands by when not printing. A maintenance device 54 for cleaning the print head 26 and the like is disposed at a position corresponding to the position immediately below the carriage 25 disposed at the home position HP. The maintenance device 54 includes a cap 55 as an example of a droplet receiving portion that functions as a lid that prevents the ink in the nozzles of the print head 26 from being thickened, and a nozzle opening surface 26a (see FIGS. 2 and 4). ) And a suction pump 57 that applies a negative pressure to the cap 55.

  When the cap 55 is lifted from the standby position (downward position) by the lifting mechanism 58 and contacts the nozzle opening surface 26a, a closed space communicating with the nozzle is formed between the cap 55 and the nozzle opening surface 26a. By applying a negative pressure from the suction pump 57 to this closed space, cleaning is performed by sucking and discharging thickened ink, bubbles, and the like in the print head 26 through the nozzles.

  Further, the cap 55 shown in FIG. 2 and FIG. 3 is a droplet receiving portion for performing flushing (empty ejection) for ejecting ink droplets as an example of droplets unrelated to printing from the nozzles of the print head 26. It serves as an example. The cap 55 is located outside the scanning area when the print head 26 is printed. Flushing is performed by ejecting ink droplets into the cap 55 by the carriage 25 moving to the flushing position FP (home position HP in this example) during printing. As shown in FIG. 2, the waste ink in the cap 55 collected by cleaning or flushing is sucked by the suction pump 57 and discharged to the waste liquid tank 60 through the tube 59, and the ink absorption in a plurality of layers in the waste liquid tank 60 is performed. Absorbed and held by the material 60a.

  As shown in FIG. 3, a linear encoder 30 is provided along the guide shaft 51 in the apparatus main body 12. The linear encoder 30 includes a tape-shaped code plate 30a in which a large number of slits are formed at fixed pitches, and an optical sensor 30b having a light emitting part and a light receiving part provided on the carriage 25. The linear encoder 30 outputs a pulse signal having a pulse number proportional to the moving distance of the carriage 25 and a cycle inversely proportional to the moving speed of the carriage 25. In the printer 11, speed control and position control of the carriage 25 are performed based on the movement position, movement speed, and movement direction of the carriage 25 detected by detecting the pulse of the pulse signal from the linear encoder 30.

  Further, from an encoder 61 (for example, a rotary encoder) attached to the end of the drive shaft of the transport roller pair 18, a transport roller pair 18 and discharge roller pairs 19, 20 (however, refer to FIG. 1 for the transport roller pair 20). ), A pulse signal having a number of pulses proportional to the rotation amount of the transport motor 62, which is a power source. The printer 11 detects the pulse of the pulse signal from the encoder 61 and performs speed control and stop position control when the paper 14 is conveyed.

  As shown in FIG. 3, the printer 11 includes a first sensor 63, a second sensor 64, and a third sensor 65 that can detect the edge of the paper 14 at predetermined locations on the feeding path and the conveyance path. They are arranged in this order from the upstream side in the direction Y (feeding direction).

  The first sensor 63 is disposed at a position upstream of the second sensor 64 in the transport direction Y and at the center of the width in the paper transport width in the scanning direction X, and is in the transport direction Y end of the fed paper 14. It has a function of detecting the part (front end and rear end).

  The second sensor 64 is a position that is downstream of the first sensor 63 and upstream of the pair of transport rollers 18 in the transport direction Y, and is a position that is the center of the width within the paper transport width in the scanning direction X. And has a function of detecting end portions (front end and rear end) of the paper 14 in the transport direction Y. In this example, a center feeding method is employed in which the paper 14 is fed in a state where the width center of the paper 14 coincides with the width center in the paper conveyance width. For this reason, the end of the sheet 14 of any size is detected by the first sensor 63 and the second sensor 64 in the transport direction Y.

  Further, the third sensor 65 (width sensor) shown in FIG. 2 and FIG. 3 is provided on the carriage 25 and receives the reflected light of the light irradiated toward the paper 14 on the support base 29 to receive the width direction ( It has a function of detecting an end (side end) in the scanning direction X). From the position of the end of the paper 14 in the scanning direction X detected by the third sensor 65 during the movement of the carriage 25, the amount of deviation of the actual position of the paper 14 in the scanning direction X from the theoretical position is grasped. By adjusting the ink ejection timing of the print head 26 performed during the movement of the carriage 25 in accordance with the positional deviation amount of the paper 14 in the scanning direction X, an image or the like is printed on the paper 14 without deviation. The

  As shown in FIG. 4, a total of 180 nozzles # 1 to # 180 arranged in a line at a constant nozzle pitch in the transport direction Y (vertical direction in FIG. 4) are formed on the nozzle opening surface 26a of the print head 26. Nozzle rows N1 to N4 of the same number (for example, four rows) as the ink colors corresponding to a plurality of ink colors (for example, four colors) are formed. In this example, a total of four nozzle rows N1 to N4 are used, and black (K), cyan (C), magenta (M), and yellow (Y) are printed as an example.

  As shown in FIG. 4, the print head 26 includes the same number of ejection drive elements 66 corresponding to the nozzles # 1 to # 180 as the number of nozzles for each nozzle row. However, in FIG. 4, only the ejection drive elements 66 corresponding to the nozzles # 1 to # 180 constituting the nozzle row N1 are schematically illustrated outside the print head 26. The ejection drive element 66 is composed of, for example, a piezoelectric vibrator or an electrostatic drive element. When a drive pulse (voltage pulse) having a predetermined drive waveform is applied, the ink chamber communicates with the nozzle by an electrostrictive action or an electrostatic drive action. Ink droplets are ejected from the nozzles by vibrating the inner wall (vibrating plate) of the ink chamber and expanding and compressing the ink chamber. For nozzles that eject ink droplets during printing, the ink is refreshed (replaced), so there is less concern about clogging. However, nozzles that do not eject ink droplets during printing are less likely to clog due to increased viscosity of the ink. I am worried. For this reason, during printing, flushing is performed to refresh ink in the nozzles by ejecting ink droplets toward the cap 55 from all the nozzles # 1 to # 180.

  Next, the electrical configuration of the printer 11 will be described with reference to FIG. As shown in FIG. 5, the controller 70 of the printer 11 is connected to the host device HC via the interface 71 in a state where the print job data D1 can be received. An operation panel 72 is electrically connected to the interface 71. The operation panel 72 includes a plurality of operation switches and a display unit (all not shown). An operation signal when the user operates the operation switch of the operation panel 72 is input to the controller 70. In addition, the controller 70 displays a menu screen, various messages, and the like on the display unit of the operation panel 72.

  The host device HC is provided with a printer driver PD for generating print job data D1. The printer driver PD performs resolution conversion processing, color conversion processing, halftone processing, and the like on the display color system image data to generate CMYK color system image data D2, and assigns a command to this to print job Data D1 is generated. The host device HC includes a personal computer, a portable information terminal (PDA (Personal Digital Assistants)), a tablet PC, a smartphone, a mobile phone, and the like.

  In addition to the interface 71 described above, the controller 70 includes a computer 73 (microcomputer) (indicated by a one-dot chain line in FIG. 5), a head drive circuit 74, and motor drive circuits 75 to 77. The computer 73 is connected with the switch system of the operation panel 72, the linear encoder 30, the encoders 61 and 68, the first sensor 63, the second sensor 64, and the third sensor 65 as input systems. Further, the display unit of the operation panel 72 and various drive circuits 74 to 77 are electrically connected to the computer 73 as an output system. The computer 73 controls the print head 26 (specifically, each ejection drive element 66) via the head drive circuit 74, and the carriage motor 53, the transport motor 62, and the feed via each motor drive circuit 75-77. The motor 67 is controlled.

  The computer 73 includes a CPU 81, an ASIC 82 (Application Specific IC), a ROM 83, a RAM 84, and a nonvolatile memory 85, which are connected to each other via a bus 86.

  The ROM 83 stores various control programs and various data. The RAM 84 temporarily stores various data such as calculation results by the CPU 81 and various data processed by the ASIC 82. The nonvolatile memory 85 stores various programs including a firmware program and various data necessary for print processing. The nonvolatile memory 85 includes a flushing information storage unit 85a (hereinafter also simply referred to as “storage unit 85a”) that stores flushing information such as flushing conditions. In the flushing information, data of a flushing interval time Tf that defines a time interval for performing flushing and data that defines a flushing amount (ink ejection amount) corresponding to an elapsed time from the end of the previous flushing are printed. It is set for each mode. For these data, for example, first reference data composed of table data indicating the correspondence between the print mode and the flushing interval time Tf, and table data indicating the correspondence between the elapsed time and the flushing amount are set for each print mode. It consists of second reference data.

  The flushing includes “printing flushing” performed during printing of one page, discharge of the paper 14 (previous page) after printing, and feeding of the next paper 14 (next page). There is “periodic flushing” performed during the page switching period. The first reference data related to the flushing interval time Tf is referred to by the computer 73 when determining the execution timing of flushing during printing, and the second reference data related to the flushing amount corresponding to the elapsed time is determined by the computer 73 when determining the conditions for periodic flushing. Referenced. Note that the page switching period in this example refers to a period from the start time of the discharge operation for the previous page to the end time of the feeding operation for the next page.

  Next, the functional configuration of the computer 73 of this embodiment will be described with reference to FIG. FIG. 6 mainly shows functional parts related to the flushing control, and other functional parts are partially omitted.

  As shown in FIG. 6, the computer 73 includes a main control unit 91, a sequence control unit 92, an image processing unit 87, and a transfer unit 88 as functional parts realized by at least one of software by the CPU 81 and hardware by the ASIC 82. Prepare. The main control unit 91 controls the printing system and the maintenance system, and instructs the sequence control unit 92 to issue various commands for the printing system and the maintenance system.

  The main control unit 91 receives requests from the print control unit 93 that controls printing, the flushing control unit 94 that controls flushing control, and the control units 93 and 94, and specifies the request destination to the sequence control unit 92. A job control unit 95 for instructing an instruction according to the sequence is provided. The job control unit 95 has a function of adjusting instructions from the control units 93 and 94, which are upper layers, and receives various requests (ink ejection start request, flushing request, carriage start request) received from the control units 93 and 94. , A transport start request, a feed start request, etc.) are commanded to the sequence control unit 92 which is a lower layer in terms of control in accordance with the priority order.

  The sequence control unit 92 performs sequence control to perform operations according to the received command in an appropriate order and timing, and is also described as a head control unit 96 and a carriage control unit 97 (“CR control unit 97”). ), A conveyance control unit 98 (also referred to as “PF control unit 98”) and a feeding control unit 99 (also referred to as “ASF control unit 99”). The CR control unit 97, the PF control unit 98, and the ASF control unit 99 include a CR counter 97A, a PF counter 98A, and an ASF counter 99A, respectively. The CR counter 97A counts, for example, the number of pulse edges on the basis of the pulse signal from the linear encoder 30 and thereby corresponds to, for example, the position of the carriage 25 (carriage position) in the scanning direction X with the home position HP as the origin. Count the numbers. The ASF counter 99A is reset when the first sensor 63 detects the leading edge of the paper 14 in the transport direction Y, and then, for example, counts the number of pulse edges based on the pulse signal from the encoder 68, so that the first Using the position of the paper 14 when the leading edge is detected by the sensor 63 as the origin, a count value indicating the leading edge position of the paper 14 in the transport direction Y is counted. The PF counter 98 </ b> A is reset when the second sensor 64 detects the leading edge of the paper 14 in the transport direction Y, and then, for example, counts the number of pulse edges based on the pulse signal from the encoder 61. Using the position of the paper 14 when the leading edge is detected by the sensor 64 as the origin, a count value indicating the leading edge position of the paper 14 in the transport direction Y is counted.

  The ASF control unit 99 performs sequence control of the feeding motor 67 via the motor drive circuit 77 according to the commanded content, and controls the feeding operation of feeding the paper 14 by the rotation of the intermediate rollers 17A, 36, etc. . The PF control unit 98 performs sequence control of the transport motor 62 via the motor drive circuit 76 according to the commanded content, and transport operation for transporting the paper 14 by the rotation of the transport roller pair 18 and the discharge roller pairs 19 and 20. The discharging operation for discharging the paper 14 after printing is controlled. Here, the speed profile in which the ASF control unit 99 controls the feeding motor 67 and the speed profile in which the PF control unit 98 controls the transport motor 62 include an acceleration region, a constant speed, and a deceleration region. A plurality of speed profiles having different maximum speeds (constant speeds) are prepared, and one speed profile having a higher maximum speed is selected as the conveyance distance of the paper 14 is longer. Depending on the transport distance, there is no constant speed area, and the speed profile consists only of an acceleration area up to the maximum speed and a deceleration area from the maximum speed.

  The CR control unit 97 monitors the carriage position from the start position of the carriage 25, refers to the CR speed table corresponding to the printing mode at that time, and sends a command value corresponding to the target speed corresponding to the carriage position to the motor drive circuit. By outputting to 75, the speed of the carriage 25 is controlled. Here, the speed profile during one-pass operation in which the carriage 25 moves once in the scanning direction X includes an acceleration area from the starting position of the carriage 25, a constant speed area in which the carriage 25 moves at a constant speed, and the carriage 25. Includes a deceleration region from a constant speed to stopping at the stop position.

  The head control unit 96 performs control to cause the print head 26 to eject ink. The head control unit 96 outputs print data D3 (dot data) generated by processing the image data D2 extracted from the print job data D1 by the print control unit 93 by the image processing unit 87 from the transfer unit 88 for one pass. , And the ejection drive element 66 (see FIG. 4) is driven based on the print data to eject ink from the nozzles of the print head 26.

  The print control unit 93 includes a main control unit 101, a command analysis unit 102, a data analysis unit 103, and a calculation unit 104. The flushing control unit 94 includes a flushing timer 111 (hereinafter referred to as “FL timer 111”), a first determination unit 112, a second determination unit 113, and a calculation unit 114. The print control unit 93 and the flushing control unit 94 output various commands of the print head system, the carriage system, the transport system, and the feeding system to the job control unit 95 that is a lower layer for control.

  The print job data D1 received from the host device HC is temporarily stored in the reception buffer 84a, and then read and acquired from the reception buffer 84a by the print control unit 93. The print job data D1 includes print condition information (print mode, paper type, paper size, etc.), a command, and image data D2.

  The main control unit 101 controls the entire print control performed by the print control unit 93 and controls the units 102 to 104. The main control unit 101 determines a control condition corresponding to the printing condition based on the printing condition information. The command analysis unit 102 divides the print job data D1 into commands and image data D2, analyzes the command and sends the command to the job control unit 95, and sends the image data D2 to the image processing unit 87. As a result, the print control unit 93 makes various requests to the job control unit 95 including a feed request, a print request, a transport request, a discharge request, and the like.

  The data analysis unit 103 analyzes the image data D2, and the print start position (first dot position) and the print end position (when the carriage 25 moves in the scanning direction X and the print head 26 performs printing for one pass) The last dot position).

  The calculation unit 104 uses the data of the print start position (first dot position Fn) and the print end position (final dot position Ln) acquired by the data analysis unit 103 to feed the paper 14 and pass one pass of the carriage 25. Control parameters necessary for ASF / CR superposition control in which the eye scanning operation is performed by superimposing at least a part of both operation timings are calculated. The print control unit 93 sends a feed request and a scan request to the job control unit 95 together with the control parameters calculated by the calculation unit 104.

  The image processing unit 87 assigns dot data to the nozzles in accordance with the printing method corresponding to the printing mode based on the image data D2, and arranges the dot data in accordance with the ejection order corresponding to the carriage movement direction. Dot array processing or the like is performed to generate print data D3 (dot data) for head control. The print data D3 is stored in the output buffer 84b and then transferred from the transfer unit 88 to the head control unit 96 for each pass. The reception buffer 84a and the output buffer 84b are configured by a part of the RAM 84.

  When it is time to perform flushing, the flushing control unit 94 acquires flushing conditions according to the execution time, and designates the flushing conditions to the print control unit 93 to make a data generation request. The print control unit 93 that has received this request sets the flushing conditions from among a plurality of types of image data Df2 used when ejecting ink droplets for flushing from all the nozzles of the print head 26 stored in the nonvolatile memory 85. The combined image data Df2 for flushing is read and output to the image processing unit 87. The image processing unit 87 performs the same processing as the image data D2 for printing on the image data Df2, generates print data Df3 (dot data) for flushing, and stores it in the output buffer 84b. The head control unit 96 controls the print head 26 based on the flushing print data Df3 received from the transfer unit 88, so that flushing that ejects ink droplets from all nozzles of the print head 26 is performed.

  Further, when the printer 11 has a copy function, the image processing unit 87 performs resolution conversion processing, color conversion processing, halftone processing, and the like on the original image data read by the scanner (not shown), and the CMYK table. Color image data D2 is generated, and the above-described processes are performed on the image data D2 to generate print data D3.

  The transfer unit 88 transfers the print data D3 or Df3 stored in the output buffer 84b to the head control unit 96 for each pass. The head controller 96 drives and controls the ejection drive element 66 for each nozzle via the head drive circuit 74 based on the print data D3 or Df3, and ejects ink droplets from the nozzle for the requested printing operation or flushing operation. The CR control unit 97 performs sequence control of the carriage motor 53 via the motor drive circuit 75 in accordance with the commanded contents, and moves the carriage 25 during the printing operation or the flushing operation to match the position of the carriage 25. The head controller 96 causes ink droplets to be ejected from the nozzles of the print head 26 at an appropriate timing.

  When the head controller 96 controls the print head 26 to eject ink, the CPU 81 has a high load due to the processing of the image data by the image processor 87, and a command that cannot be output from the job controller 95. It is a prohibited period.

  Here, details of the ASF / CR overlay control for superimposing at least a part of the operation timing of the feeding operation of the paper 14 and the scanning operation of the carriage 25 will be described. The calculation unit 104 calculates the carriage movement time Tcr2 required for the movement from the flushing position FP to the print start position of the first pass of the next page during the page switching period, and from the flushing position FP to the print start position of the first pass of the next page. Calculation is performed using the speed profile data of the carriage motor 53 according to the distance and the printing mode at that time. Specifically, the calculation unit 104 calculates a distance Sfl (step number) from the flushing position FP to the print start position. Then, the calculation unit 104 uses the acceleration time Ta acquired based on the CR speed data corresponding to the printing mode at that time, and the constant speed distance Sc (= Sfl−Sa) obtained by subtracting the acceleration distance Sa from the distance Sfl. The carriage movement time Tcr2 is calculated by adding the constant speed time Tc obtained by dividing by the constant speed Vc (Tcr2 = Ta + (Sfl−Sa) / Vc).

  Further, the calculation unit 104 calculates a transport amount ΔS (number of transport steps) corresponding to the carriage movement time Tcr2 from the current feed end position (cue position) to the upstream side in the transport direction Y, and the feed end position (head position) The position just before the carry amount ΔS from the (delivery position) is calculated as the CR activation request position. The carry amount ΔS is notified to the job control unit 95. The job control unit 95 grasps the remaining transport amount ΔSr up to the feed end position during the feeding operation from the count value of the PF counter 98A of the PF control unit 98, and when the remaining transport amount ΔSr reaches the transport amount ΔS. A carriage activation command is output to the CR control unit 97 (when the CR activation request position is reached). In this way, the feeding operation is completed and the paper 14 is stopped. At the same time, the print head 26 reaches the printing start position of the first pass of the next page, and ink droplet ejection is started. The initial portion of the scanning operation for the first pass on the next page of the carriage 25 is superimposed.

  The print control unit 93 requests the job control unit 95 to perform ASF / CR control for starting the driving of the feeding motor 67 when the carriage 25 reaches the print end position (final dot position) in the final pass of the previous page. To do. When the print head 26 reaches the print end position in the final pass of the previous page, the job control unit 95 issues a feeding command and a conveyance command to the PF control unit 98 and the ASF control unit 99. The PF control unit 98 and the ASF control unit 99 that have received this command start driving of the transport motor 62 and the feed motor 67 via the motor drive circuits 76 and 77. In this way, the feed operation of the next page is started as soon as the print head 26 reaches the print end position in the final pass of the previous page, and the final part of the scanning operation of the final pass of the carriage 25 and the initial stage of the feed operation of the next page. Are superimposed on each other.

  6 controls the flushing that causes the carriage 25 to move to the flushing position FP during the execution of the print job and ejects ink from all the nozzles of the print head 26. As described above, the flushing control unit 94 includes the FL timer 111, the first determination unit 112, the second determination unit 113, and the calculation unit 114 shown in FIG.

  The FL timer 111 measures the elapsed time from the end of the previous flushing until the elapsed time reaches the flushing interval time Tf. When the FL timer 111 finishes counting the flushing interval time Tf, the flushing control unit 94 requests the print control unit 93 to generate print data Df3 for flushing, and also performs a flushing operation to the job control unit 95. Require implementation.

  The flushing interval time Tf of this embodiment is basically set so that the FL timer 111 finishes counting the flushing interval time Tf while the carriage 25 is scanning in the backward movement direction from the full side to the home side. Yes.

  The first determination unit 112 determines whether or not to perform flushing during printing during printing of one page. During the scanning of the carriage 25, it is determined whether the elapsed time Tm measured by the FL timer 111 has reached the flushing interval time Tf set in advance for each print mode (Tm ≧ Tf is satisfied). When this condition Tm ≧ Tf is satisfied, the flushing control unit 94 issues a flushing request to the job control unit 95 and requests the print control unit 93 to generate dot data for flushing. At this time, the print controller 93 extends the scanning end position of the carriage 25 to the flushing position FP (home position HP), and causes the print head 26 to perform flushing when the carriage 25 reaches the flushing position FP.

  When receiving the flushing request, the job control unit 95 instructs the CR control unit 97 to execute the flushing sequence. Receiving this command, the CR control unit 97 controls the carriage motor 53 to move the carriage 25 to the flushing position FP. Further, the print control unit 93 sends the image data Df 2 for flushing read from the nonvolatile memory 85 to the image processing unit 87. Then, the image processing unit 87 generates print data Df3 for flushing based on the image data Df2, and stores it in the output buffer 84b.

  In addition, the second determination unit 113 performs various determinations related to regular flushing. The second determination unit 113 determines whether or not the movement direction of the carriage 25 in the final pass is a backward movement direction from the full side toward the home side (that is, approaches the flushing position FP) at the page switching time. If the determination result of the second determination unit 113 indicates that the movement direction of the carriage 25 in the final pass is the backward movement direction, the flushing control unit 94 performs regular flushing, but moves from the home side to the full side (that is, the flushing position). If it is in the forward direction (away from the FP), periodic flushing is not performed. This is because when the moving direction of the carriage 25 in the final pass is away from the flushing position FP, the time required for the carriage 25 to move from the final pass end position to the home-side flushing position FP becomes long. This is because the execution of flushing causes a significant delay in the printing start timing of the next page.

  The calculation unit 114 delays the start timing of the next operation that occurs when the periodic flushing operation is performed by superimposing at least a part of the operation timing on one of the plurality of operations constituting the feeding operation. The time is calculated for each operation by sequentially changing the operation to be superimposed. That is, the calculation unit 114 calculates delay times Δt1, Δt2, and Δt3 (see FIGS. 14 to 20).

  The second determination unit 113 performs a size comparison determination of the delay times Δt1, Δt2, and Δt3 calculated by the calculation unit 114, and determines at least a part of the flushing operation and the operation timing among a plurality of operations included in the feeding operation. In the case of superimposing, one operation that satisfies the condition that can minimize the delay time Δt of the start time of the next operation is determined.

  When the carriage movement direction of the final path is the backward movement direction and the flushing is to be executed, the flushing control unit 94 acquires the elapsed time from the end of the previous flushing operation at that time from the FL timer 111. . Then, the flushing control unit 94 refers to the second reference table based on the elapsed time and acquires the flushing amount corresponding to the elapsed time. Further, the flushing control unit 94 requests the print control unit 93 to generate the flushing print data Df3 corresponding to the flushing amount, and requests the job control unit 95 to perform flushing.

  Next, the feeding operation will be described with reference to FIGS. In the feeding process, there is a risk that a skew (skew) in which the paper 14 is inclined obliquely with respect to the feeding direction may occur. For this reason, the printer 11 performs a skew removal operation for removing the skew during the feeding operation. As the skew removal operation, there are mainly two methods that are selectively used according to the print mode. One is the “eating discharge method”, and the other is the “reverse butting method”. Hereinafter, each of these methods will be described.

  First, the eating and discharging method will be described with reference to FIG. As shown in FIG. 7, the feeding operation of the biting discharge method includes the initial biting operation shown in FIG. 7 (a), the skew 8 removing operation shown in FIG. 7 (b), and FIG. 7 (c). Three operations including the cue operation shown are included in this order. The driving direction of the feeding motor 67 that can rotate the intermediate roller 17A in the sheet feeding direction (counterclockwise direction (arrow direction) in FIG. 7A) is defined as a normal rotation direction. In addition, the driving direction of the conveying motor 62 that can rotate the conveying driving roller 18A in the paper feeding direction (counterclockwise direction (arrow direction in FIG. 7A)) is the forward rotation direction, and the reverse driving direction is the reverse rotation direction. And

  As shown in FIG. 7A, first, in the initial biting operation, the feed motor 67 and the transport motor 62 are driven to rotate forward. Then, as shown in FIG. 7A, after the leading end of the paper 14 reaches the conveyance roller pair 18 and is nipped (nip), the paper 14 is further moved from the conveyance roller pair 18 to the downstream side in the conveyance direction Y by a predetermined length. When the sheet is transported to such a position that protrudes, the driving of the feeding motor 67 and the transport motor 62 is stopped. In this way, the biting operation is performed.

  As shown in FIG. 7B, in the next skew removal operation (discharge operation), the transport motor 62 is rotated in the reverse direction with the feeding motor 67 stopped and the rotation of the intermediate rollers 17A and 36 stopped. Driven to reverse the conveying roller pair 18. As a result, a discharge operation is performed in which the leading edge of the paper 14 is returned to a position further upstream than the nipping position (nip point) of the conveying roller pair 18. That is, the leading end of the paper 14 is discharged from the transport roller pair 18 to the upstream side in the transport direction while being bent at a portion between the intermediate roller 17A and the transport roller pair 18 of the paper 14. As shown in FIG. 7B, the leading edge of the discharged paper 14 is abutted against the conveying roller pair 18 that is rotating backward or stopped by the restoring force due to the bending, and the paper 14 is caused to be The entire side is aligned so as to contact the conveying roller pair 18, and thereby skew (skew) is almost eliminated.

  When the reverse rotation for the discharge operation of the transport roller pair 18 is finished, as shown in FIG. 7C, the driving of the feeding motor 67 in the normal rotation direction is resumed and the transport motor 62 is rotated from the reverse rotation to the normal rotation. Switch to. As a result, the intermediate rollers 17A and 36 are rotated forward, and the rotation of the transport motor 62 is switched from reverse rotation to normal rotation to switch the transport roller pair 18 from reverse rotation to normal rotation. As a result, the skew removal operation is switched to the cue operation, and the paper 14 from which the skew has been removed is cued to the print start position. Since at least one of the motors 62 and 67 is switched between the initial biting, skewing and cueing operations, it is necessary to issue a command from the main control unit 91 to the sequence control unit 92 when switching these operations. There is.

  Next, with reference to FIG. 8, the skew removal operation of the reverse contact method will be described. As shown in FIG. 8A, the paper 14 is fed by driving the feed motor 67 forward and the intermediate rollers 17A and 36 forward, and the leading end of the paper 14 in the transport direction Y is transported. Before reaching the roller pair 18, the reverse drive of the transport motor 62 is started to bring the transport roller pair 18 into a reverse state. As a result, as shown in FIG. 8A, the skewed sheet 14 strikes the pair of conveying rollers 18 whose corners at the front end thereof are reversed, and thereafter, the sheet 14 rotates around the corners against which the sheet 14 abuts. As a result, the skew of the paper 14 is almost eliminated.

  Then, when the conveyance roller pair 18 is reversed by a set rotation amount that can eliminate the skew of the assumed maximum skew amount in a state in which the sheet 14 hits the reverse conveyance roller pair 18, as shown in FIG. 8B. In addition, the driving direction of the transport motor 62 is switched from reverse rotation to normal rotation. As a result, the transport roller pair 18 is switched from reverse rotation to normal rotation under a state where the intermediate rollers 17A and 36 rotate forward. Thus, the reverse rotation butting operation (skew removal operation) is switched to the cueing operation, and the cueing is performed in which the paper 14 from which the skew has been removed is conveyed to the print start position. Since the operation of at least one of the motors 62 and 67 is switched between the reverse rotation butting operation and the cueing operation, the main control unit 91 transfers the operation to the sequence control unit 92 as in the case of the above-mentioned biting discharge method. It is necessary to issue a command for switching. In the present embodiment, the operation constituting the feeding operation is an operation that requires switching of the driving state of at least one of the motors (power sources) used for the feeding operation in order to start the operation. Say.

  10 and 11 show the motor control in the feeding operation of the biting discharge method (FIG. 10) and the reverse contact method (FIG. 11) in the page switching period. In these drawings, the speed profiles of the carriage motor 53, the transport motor 62, and the feeding motor 67 are shown in order from the top, and the horizontal axis represents time. At the bottom of these figures, the signal level of the detection signal of the second sensor 64 that detects the leading edge of the paper 14 in the feeding process is shown. Further, in the constant speed area on the left side of the carriage motor 53, the print head 26 prints the last pass of the previous page (hatched portion in the figure), and in the constant speed area on the right side of the figure, the next page by the print head 26 is printed. The first pass printing (hatched portion in the figure) is performed.

  In this embodiment, in each pass during printing, the print start position is in the middle of the acceleration area of the carriage motor 53 (that is, the carriage 25), and the print end position is in the middle of the deceleration area. However, at the time of page switching, after moving from the printing end position of the last pass of the previous page to the extension position at a constant speed, it is decelerated and stopped at the flushing position FP, and then acceleration is started from the flushing position FP. 10 and 11, both the print end position and the print start position are located in the constant speed region.

  First, the eating and discharging method will be described with reference to FIG. When the carriage 25 reaches the print end position where the ink ejection by the print head 26 is completed in the final pass of the previous page, first of the feeding operation, the feeding motor 62 and the feeding motor 67 are started to start the initial biting operation. Driving is started. At this time, each of the motors 62 and 67 is driven in the forward rotation direction to feed the paper 14 from the transport roller pair 18 to a position where the leading end protrudes downstream in the transport direction by a predetermined bite amount. Operation is performed. During the initial biting operation, the PF counter 98A starts counting from the position where the leading edge of the paper 14 is detected by the second sensor 64. When the count value becomes a value corresponding to the desired biting amount, both motors The driving of 62 and 67 is stopped.

  When the driving of both motors 62 and 67 is stopped after the initial biting operation is completed, the transport motor 62 is driven in the reverse direction while the feed motor 67 is held in the stopped state, and the transport roller pair 18 is discharged by the discharge amount. A skew removal operation (discharge operation) is performed in which the front end portion of the paper 14 is reversed and discharged to the upstream side of the conveyance roller pair 18 in the conveyance direction. By the skew removal operation, the sheet 14 is ejected while being bent, so that the skew of the sheet 14 is removed when the sheet 14 returns to its original state by the restoring force of the bending.

  When the skew removal operation is finished and the reverse rotation drive of the transport motor 62 is stopped, the transport motor 62 and the feed motor 67 are next driven to rotate forward, and the intermediate rollers 17A, 36 and the transport roller pair 18 are rotated. Then, a cueing operation for carrying the paper 14 to a cueing position that is a printing start position in the carrying direction Y is performed. In the middle of this cueing operation, the carriage motor 53 starts to be driven, the carriage 25 starts scanning the first pass of the next page from the flushing position FP, and at the same time the cueing operation stops, it reaches the print start position and reaches the print head. 26 starts printing by ejecting ink.

  Next, the reverse rotation abutting method will be described with reference to FIG. When the carriage 25 reaches the printing end position where the ejection of ink by the print head 26 ends in the final pass of the previous page, the driving of the feeding motor 67 is started, and the abutting operation is first started in the feeding operation. At this time, the transport motor 62 is driven simultaneously with the feeding motor 67, and the preceding paper 14A (previous page) is discharged (discharged) by the rotation of the transport roller pair 18. Then, after the discharge operation (paper discharge operation) is finished and the drive of the transport motor 62 is stopped, the reverse drive of the transport motor 62 is started, and the transport roller pair 18 is reversely rotated. Then, the leading edge of the succeeding paper 14B hits the conveying roller pair 18 that is rotating in the reverse direction, and this reverse rotation abutting state is maintained for a predetermined time, whereby the skew removing operation (reverse rotation abutting operation) is performed.

  Then, when a predetermined time has elapsed from the start of the skew removal operation, the driving of both motors 62 and 67 is stopped. Specifically, the count value of the PF counter 98A, which starts counting from the position where the leading edge of the paper 14 is detected by the second sensor 64, corresponds to the condition at the time when the leading edge of the succeeding paper 14B hits the conveying roller pair 18 and further. When the value when the conveying roller pair 18 is rotated by a predetermined reverse abutting amount is reached, the driving of the motors 62 and 67 is stopped.

  Next, both the transport motor 62 and the feed motor 67 are driven to rotate forward, and the head that transports the paper 14 to the print start position (cue position) in the transport direction Y by the rotation of the intermediate rollers 17A and 36 and the transport roller pair 18. The take-out operation is performed. In the middle of this cueing operation, the carriage motor 53 starts to be driven, the carriage 25 starts the scanning operation for the first pass of the next page from the flushing position FP, and at the same time the cueing operation stops, the carriage 25 moves to the printing start position. At this time, printing (ink ejection) by the print head 26 is started.

  Next, the feeding operation of the succeeding sheet 14B during the printing of the preceding sheet 14A will be described with reference to FIG. In the printer 11 of the present embodiment, the feeding operation of the succeeding sheet 14B is performed in parallel while the preceding sheet 14A is being printed, and the transport of the preceding sheet 14A and the succeeding sheet are maintained while maintaining the interval between the preceding sheet 14A and the succeeding sheet 14B. Inter-page control is performed in which 14B feeding is performed in parallel. In order to realize this interpage control, a first sensor 63 capable of detecting the trailing edge of the preceding sheet 14A and the leading edge of the succeeding sheet 14B is used at a predetermined position on the feeding path.

  When the trailing edge of the preceding sheet 14A shown in FIG. 9 is detected by the first sensor 63, the feeding motor 67 or the power source 48 is driven to drive the pickup roller 33 or 43 to start feeding the succeeding sheet 14B. Then, a predetermined interval Lg is secured between the preceding sheet 14A and the succeeding sheet 14B. The position of the trailing edge of the preceding sheet 14A is managed by the number of steps of the encoder 61 after the trailing edge is detected by the first sensor 63 by the PF counter 98A. The position of the leading edge of the succeeding paper 14B is managed by the ASF counter 99A based on the number of steps of the encoder 68 after the leading edge is detected by the first sensor 63. Then, when the trailing edge position of the preceding sheet 14A reaches a set value (for example, a converted value of the number of steps of the interval Lg), the feeding of the succeeding sheet 14B is started, and management is performed after the leading edge is detected by the first sensor 63. The transport motor 62 and the feed motor 67 are driven and controlled so that the distance Lg is maintained between the position of the leading edge and the position of the trailing edge of the preceding paper 14A. Note that the position of the trailing edge of the preceding sheet 14A may be obtained by adding the count value of the PF counter 98A indicating the position of the leading edge of the preceding sheet 14A and the sheet length. In this case, the sheet length may be obtained from the sheet size information, or the first sensor 63 and the second sensor are added to the count value of the ASF counter 99A when the trailing edge of the preceding sheet 14A is detected by the first sensor 63. You may acquire from the value which added the number of steps for the conveyance distance between 64.

  After the interval Lg is ensured in this way, when the preceding sheet 14A is conveyed, the succeeding sheet 14B is fed by the same distance, so that the preceding sheet 14A is conveyed and the succeeding sheet 14B is supplied while the interval Lg is maintained. Sending proceeds in parallel. For this reason, the subsequent sheet 14B is fed relatively quickly after the discharge of the preceding sheet 14A is started at the time of page switching. Thus, during the printing of the preceding paper 14A, the inter-page control that advances the feeding of the succeeding paper 14B while maintaining the small interval Lg may be performed only in the high-speed printing mode (draft mode), or all printing It may be implemented in a mode. Note that the position of the first sensor 63 may be changed to an appropriate position on the feeding path where inter-page control can be performed. For example, it may be provided at a position upstream of the roller 37 in the feeding direction.

  Next, with reference to FIG. 12, a flushing operation in a process from when the printing of the previous page is finished and before the fed paper 14 is printed and the next page of paper is fed will be described. In FIG. 12, the carriage 25 is omitted, and the scanning path is shown by the print head 26, and the movement path (scanning path) of the print head 26 is a relative movement path with respect to the paper 14 conveyed in the conveyance direction Y. It is drawn in.

  As shown in FIG. 12, the movement (scanning operation) of the print head 26 (that is, the carriage 25) in the scanning direction X and the transporting operation of the paper 14 in the transporting direction Y overlap each other. By repeating substantially alternately, an image or the like is printed on the paper 14. Specifically, the print head 26 prints one line (one line) on the paper 14 by ejecting ink from the nozzles during one pass that moves once in the scanning direction X. After the first scanning, the sheet 14 is conveyed by the conveyance amount Δy. In the example of FIG. 12, the print head 26 performs printing in both the forward and backward scans in the scanning direction X.

  The print head 26 that has moved to the flushing position FP after printing the previous page performs regular flushing, starts scanning the first pass from the flushing position FP in the middle of feeding the paper 14, and prints the first pass. Next, the conveyance of the conveyance amount Δy1 of the first sheet 14 is performed. Then, after the second pass scanning is performed, the second conveyance of the sheet 14 by the conveyance amount Δy2 is performed. Hereinafter, similarly, scanning and conveyance are performed approximately alternately. Time measurement is started by the FL timer 111 (see FIG. 6) from the end of the first regular flushing. If, for example, the time measured by the FL timer 111 reaches the flushing interval time Tf during the printing of the Kth pass during printing, the scanning of the printhead 26 of the Kth pass is extended and moved to the flushing position FP. The print head 26 performs flushing during printing. The FL timer 111 reset by execution at the time of flushing starts timing from the end of the flushing during printing. Hereinafter, similarly, the printing head 26 extends the scanning to the flushing position at every flushing interval time Tf, and flushing during printing is executed. Then, the scanning to the home side of the final pass (Nth pass) is extended to move to the flushing position FP, and regular flushing is executed. When the regular flushing is finished, the FL timer 111 starts measuring from the end of the regular flushing, and the print head 26 starts moving the first pass of the next page from the flushing position FP in the middle of the feeding operation of the next page. Printing by ink ejection is started from the printing start position (ink ejection start position) of the pass.

  During flushing during printing, it is necessary to move the carriage 25 to the flushing position FP (home position HP) and return to the printing area again, so that the movement time of the reciprocating distance is one of the causes of a decrease in printing throughput. Therefore, in this embodiment, regular flushing is performed in which the carriage 25 moves to the flushing position FP and ejects ink droplets toward the cap 55 during the page switching period. By performing the regular flushing, it is possible to relatively reduce the frequency of performing the flushing during printing that is performed at each flushing interval time Tf during the printing of the succeeding paper 14B. In this example, the cap 55 is used as the droplet receiving portion. However, the flushing may be performed separately from the cap 55 toward a box, hole, or groove dedicated to flushing. Further, the flushing position is not limited to the position of one end on the movement path of the carriage 25, but is set to both end positions, and the final path of the carriage 25 is directed toward the droplet receiving portion both during the forward movement and during the backward movement. Flushing for discharging ink droplets may be performed.

  For example, as shown in FIG. 13, in the case where the regular flushing is performed immediately after the carriage 25 extended in the last pass of the previous page stops at the flushing position FP, the regular flushing operation includes the initial biting operation and the operation timing. At least a part of is superimposed. Here, since the flushing operation is a process of ejecting ink from all the nozzles, the data processing by the image processing unit 87 is large and the load on the CPU 81 is large. For this reason, it is a command prohibition period during which the command from the job control unit 95 to the sequence control unit 92 cannot be performed during the flushing operation. Therefore, in order to perform the regular flushing operation by superimposing at least a part of the operation time on one of the plurality of operations in the feeding operation, at least before the start of the regular flushing operation (for example, immediately before). It is necessary to instruct the execution of the operation to be superimposed. In other words, when the operation to be superimposed is started, the regular flushing operation needs to be stopped before the start.

  In the page switching period, a data writing process for writing data of ink consumption (or ink remaining amount) in a memory element (not shown) attached to the container 27 is executed, and ink droplets are discharged from the print head 26. A head temperature monitoring process for monitoring the temperature of the print head 26 based on the detection value of the temperature sensor at the time of executing the ejecting operation is executed. These processes also contribute to increase the burden on the CPU 81 during the period of the regular flushing operation.

  As shown in FIG. 13, when the last pass scanning of the previous page is extended and the regular flushing operation is executed immediately after the carriage 25 stops at the flushing position FP, the initial biting operation is performed as in the example of FIG. If the regular flushing has not been completed even after the completion, the next skew removal operation cannot be started within the command prohibition period until the regular flushing is completed. For this reason, after completion of the initial biting operation, a command is issued after the end of the regular flushing operation, and a delay of Δt occurs at the start time of the next skew removal operation started by the command.

  Here, each operation time of a plurality of operations constituting the feeding operation (in the example of FIG. 13, “initial biting operation”, “skewing operation”, “cueing operation”) and periodic flushing operation is Varies according to printing conditions. For this reason, in the present embodiment, the following control is performed in order to suppress a decrease in the throughput of the feeding operation caused by this type of delay time Δt. That is, the delay time Δt of the start timing of the next operation that occurs when the flushing operation is performed by superimposing at least a part of the operation timing on one of the plurality of operations constituting the feeding operation, Estimation is performed for each operation to be superimposed. And one operation | movement which satisfy | fills the condition which can minimize delay time (DELTA) t among several operation | movement is selected dynamically as operation | movement of the superimposition object of regular flushing operation | movement.

  The operation times Tpf1, Tpf2, Tpf3, and Tfl of the plurality of operations and the periodic flushing operations that constitute the feeding operation shown in FIGS. 14 to 17 vary as follows depending on the printing conditions at each time. 14 shows an example in which the periodic flushing operation is partially overlapped with the initial biting operation, FIGS. 15 and 17 are examples in which the periodic flushing operation is partially overlapped with the skew removal operation, and FIG. 16 shows the periodic flushing operation. This is an example in which a part of the feeding operation is overlapped.

  First, the regular flushing operation time Tfl depends on the flushing amount (ink discharge amount), and this flushing amount depends on the elapsed time Tm from the end of the previous flushing. Further, the correspondence between the elapsed time Tm and the flushing amount is different for each print mode, and the flushing amount is different if the print mode is different even if the elapsed time Tm is the same. For this reason, the regular flushing operation time Tfl depends on the “printing mode” and the “elapsed time Tm”.

  Further, it is equal to the flushing movement time Tcr1 (hereinafter also referred to as “FL movement time Tcr1”) required for the carriage 25 to move from the printing end position (final dot position) of the last pass of the previous page to the flushing position FP. The flushing movement time Tcr1 depends on the movement distance (number of steps) of the carriage 25 that moves from the printing end position of the last pass of the previous page to the flushing position FP and the carriage movement speed at that time. This moving distance depends on the print end position of the last pass of the previous page, which depends on the print pattern (print data) of the previous page. The carriage moving speed depends on the printing mode. Therefore, the flushing movement time Tcr1 depends on “print data” and “print mode”.

  The initial biting operation time Tpf1 depends on the conveyance speed of the paper 14 determined from the rotation speeds of the rollers 17A, 36, and 18A and the conveyance distance from the feeding start position to the biting position. The conveyance speed depends on the printing mode. The feeding start position depends on the print data of the previous page because it is determined by the leading edge position of the next page at the end of printing the previous page. Further, the amount of biting, which is the protruding length of the paper 14 from the pair of transport rollers 18 to the downstream side in the transport direction, is a paper type such as plain paper, photographic paper, cardboard, etc., and A4 size, B4 size, A3 size, L size, postcard It changes according to the paper size. For example, the thicker the paper 14, the larger the amount of biting, and the larger the paper size, the larger the amount of biting. Therefore, the initial biting operation time Tpf1 depends on “print mode” and “paper information” (“paper type” and “paper size”).

  The skew removal operation time Tpf2 (discharge operation time) depends on the transport speed at the time of discharge and the discharge amount, which is the reverse rotation amount of the transport roller pair 18 for discharging the paper 14. The conveyance speed depends on the printing mode, the discharge amount depends on the biting amount, and the biting amount depends on the paper information (paper type and paper size). Therefore, the skew removal operation time Tpf2 depends on the “print mode” and the “paper information” (paper type and paper size), similarly to the biting operation time.

  The cueing operation time Tpf3 depends on the carrying speed and the cueing distance (carrying distance) from the position of the carrying roller pair 18 to the printing start position (cueing position) of the next page. The conveyance speed depends on the print mode, and the cue distance depends on the print pattern (print data) of the next page. Therefore, the cueing operation time Tpf3 depends on “print mode” and “print data”.

  The carriage movement time Tcr2 required for the carriage 25 after the completion of the regular flushing operation to move from the flushing position FP to the printing start position (first dot position) of the first pass on the next page is 1 on the next page from the flushing position FP. It depends on the moving distance to the printing start position of the pass and the carriage moving speed at that time. This moving distance depends on the print start position of the first pass of the next page, and this depends on the print pattern (print data) of the next page. Therefore, the carriage movement time Tcr2 depends on “print data” and “print mode”.

  Also, in the reverse contact method shown in FIGS. 18 to 20, each operation of a plurality of operations (“butting operation”, “skewing operation”, “cueing operation”) during the regular flushing operation and the feeding operation. The times Tfl, Tpf1, Tpf2, and Tpf3 change as follows depending on the printing conditions at that time. 18 shows an example in which the periodic flushing operation is superimposed on the butting operation, FIG. 19 shows an example in which the periodic flushing operation is superimposed on the skew removal operation, and FIG. 20 shows an example in which the periodic flushing operation is superimposed on the cueing operation. is there.

  The regular flushing operation time Tfl and the cueing operation time Tpf3 are basically the same as the biting discharge method. That is, the regular flushing operation time Tfl depends on the “print mode” and the “elapsed time Tm”, and the cue operation time Tpf3 depends on the “print mode” and the “print data (print pattern)”.

  The abutting operation time Tsf1 includes a conveyance time Tsf11 required to convey the paper 14 until the leading end abuts against the conveyance roller pair 18, and a reverse rotation abutting that holds the paper 14 in a state of abutting against the reverse conveyance roller pair 18. And holding time Tsf12 (Tsf1 = Tsf11 + Tsf12). The conveyance time Tsf11 depends on the conveyance distance from the feeding start position of the paper 14 until the leading edge reaches the conveyance roller pair 18 and the conveyance speed at that time. Since the feeding start position is the leading edge position of the next page that is located at a distance Lg from the trailing edge of the previous page at the end of printing, the transport distance depends on the print data (print pattern) of the previous page. Further, the conveyance speed depends on the printing mode. Therefore, the transport time Tsf11 depends on the “print data (print pattern) of the previous page” and the “print mode”. Further, the reverse rotation holding time Tsf12 is equal to the skew removal operation time Tpf2.

  Here, the skew removal of the paper 14 by the reverse abutting method is realized by the paper 14 turning around the corner after the leading edge of the skewed paper 14 hits the conveying roller pair 18. Therefore, the skew removal operation time Tpf2 is set as a time obtained by adding a little margin time to the holding time necessary for turning until the skew of the paper 14 having the assumed maximum skew angle is eliminated. The rotational speed of the paper 14 at this time depends on the “printing mode” that determines the rotational speed of the intermediate roller 17A, and the rotational speed becomes slower as the paper size increases, and therefore depends on the “paper size”.

  In addition, the frictional resistance when the paper 14 is rotated differs depending on the paper type. The larger the frictional resistance, the slower the rotational speed of the paper 14. Therefore, the paper type with the higher frictional resistance increases the skew removal operation time Tpf <b> 2. It is set. The rotational speed of the paper 14 also depends on the “paper type”. Therefore, the skew removal operation time Tpf2 depends on “print mode” and “paper information (paper size and paper type)”. The abutting operation time Tsf1, which is the sum of the transport time Tsf11 and the reverse abutting holding time Tsf12 (= Tpf2), is “print mode”, “print data for the previous page”, and “paper information (“ paper size ”). "Paper type") ".

  Also, during the skew removal operation time Tpf2, since the transport roller pair 18 needs to be reversed, it is necessary to match the end times of the abutting operation and the skew removal operation. For example, as shown in FIG. 18, when the skew removal operation is started after the end of the regular flushing, in order to match the end time of the abutment operation with the end time of the skew removal operation, the start time of the abutment operation Need to delay. The flushing movement time Tcr1 and the carriage movement time Tcr2 are the same as in the case of the biting discharge method, and both depend on “print data (print pattern)” and “print mode”.

  By the way, when performing flushing during printing, it is necessary to move from the position in the print area to the flushing position FP, perform flushing, and then return to the print start position of the next pass, resulting in loss of time and printing. The throughput is reduced. Therefore, in the present embodiment, periodic flushing is performed during the page switching period to reduce the frequency of performing flushing during printing, thereby improving the print throughput. In addition, by performing at least a part of the operation timing on one of the feeding operations, the flushing operation is not delayed so much even if periodic flushing is performed during the page switching period. I am doing so.

  Here, as described above, the feeding operation includes three operations of an initial biting operation, a skew removal operation, and a cueing operation in the case of the biting discharge method. Further, in the case of the reverse rotation abutting method, it consists of two operations, a reverse rotation abutting operation and a cueing operation.

  In this embodiment, a command from the main control unit 91 in the computer 73 to the sequence control unit 92 is prohibited during execution of a flushing operation based on a request from the flushing control unit 94.

  For example, as shown in FIG. 13, after the carriage 25 that has finished printing the final pass moves to the flushing position FP and stops, a regular flushing operation for ejecting ink droplets from the print head 26 is executed. In this case, the regular flushing is performed during the initial eating operation performed by the power of the transport motor 62 that has been driven from the end of printing the last pass of the previous page, and the regular flushing operation is performed as the initial eating operation. And proceed in parallel with some. However, since the command is prohibited during the regular flushing operation, the driving of the transport motor 62 for the next skew removal operation cannot be started even after the initial biting operation is completed. For this reason, in the example of FIG. 13, even after the initial biting operation is completed, it is necessary to wait for the end of the regular flushing operation, so a delay time Δt occurs at the start time of the next skew removal operation.

  Then, the delay time Δt of the start time of the next operation that varies depending on which of the plurality of operations in the feeding operation is performed with at least a part of the operation time overlapped. Therefore, in this embodiment, the calculation unit 114 calculates the delay time Δt for each operation to be overlapped with the regular flushing operation.

  Next, a delay time calculation method will be described with reference to FIGS. First, a method of calculating the delay times Δt1, Δt2, and Δt3 in the eating and discharging method will be described with reference to FIGS. The initial biting operation time Tpf1 required for the initial biting operation is the sum of the acceleration time Ta1, the constant speed time Tc1, and the deceleration time Td1 of the initial biting operation. Therefore, Tpf1 = Ta1 + Tc1 + Td1.

  Further, the carriage 25 moves from the printing end position Xend to the flushing position Xfl (hereinafter also referred to as “FL position Xfl”) on the coordinate (X coordinate) in the scanning direction X with the home position HP as the origin until it stops. The flushing movement time Tcr1 required for the above is expressed as follows. That is, the flushing movement time Tcr1 is the sum of the constant speed time Tc1 at which the carriage 25 moves at a constant speed from the printing end position of the final pass and the deceleration time Td1 until the carriage 25 starts to decelerate and stops. Therefore, Tcr1 = Tc1 + Td1.

  In addition, in the process of moving to the FL position Xfl after the printing is completed, a dedicated low speed may be set. In this case, Tcr1 is a deceleration time Td11 required to decelerate at a deceleration β1 from a constant speed Vcr of the carriage 25 during printing to a constant speed Vfl for flushing, and a constant speed time Tc11 that moves at a constant speed Vfl for flushing. And the deceleration time Td11 required to decelerate at the deceleration β2 from the constant speed Vfl to the FL position Xfl. Therefore, Tcr1 = Td11 + Tc11 + Td11. At this time, since the print end position Xend and the FL position Xfl (for example, zero) are also known, the distance Df (= Xend−Xfl) from the print end position Xend to the FL position Xfl is obtained. Since the constant speeds Vcr and Vfl and the decelerations β1 and β2 are known, the FL movement time Tcr1 can be calculated.

The time required for the initial biting operation is defined as an initial biting operation time Tpf1, and the time required for the regular flushing operation is defined as a regular flushing operation time Tfl. A delay time Δt1 (see FIG. 14) that occurs when at least a part of the operation timing is overlapped with the initial flashing operation is represented by the following equation.
Δt1 = Tcr1 + Tfl−Tpf1 (1)
Further, the delay time Δt2 (see FIG. 15) that occurs when the regular flushing operation is overlapped with the skew removal operation at least in part by the operation time is expressed by the following equation.
Δt2 = Tfl−Tpf2 (2)
Furthermore, the delay time Δt3 (see FIG. 16) that occurs when the periodic flushing operation is overlapped with the cueing operation at least part of the operation time is expressed by the following equation.
Δt3 = Tfl + Tcr2−Tpf3 (3)
Further, a delay time Δt2 (see FIG. 17) that occurs when the periodic flushing operation is overlapped at least partially in the operation timing from the middle of the skew removal operation is expressed by the following equation.
Δt2 = Tcr1 + Tfl−Tpf1−Tpf2 (4)
When the values of Δt1 to Δt3 are negative values, the delay times Δt1 to Δt3 are set to zero (Δt = 0).

  Next, with reference to FIG. 18 to FIG. 20, a method for calculating the delay time in the case where the reverse abutting type skew removal is performed will be described. As described above, the reverse rotation abutting method includes the abutting operation by the feeding motor 67, the reverse rotation operation (skewing operation) by the transport motor 62, and the cueing operation by both the motors 62 and 67. A time required for the abutting operation by driving the feeding motor 67 is defined as an abutting time Tsf1.

A delay time Δt1 (see FIG. 18) that occurs when at least a part of the operation timing is overlapped with the abutting operation by the periodic flushing operation is expressed by the following equation.
Δt1 = Tcr1 + Tfl + Tpf2-Tsf1 (5)
Further, the delay time Δt2 (see FIG. 19) that occurs when at least a part of the operation timing is overlapped with the skew removal operation (reverse operation) in the regular flushing operation is expressed by the following equation.
Δt2 = Tfl−Tpf2 (6)
Furthermore, the delay time Δt3 (see FIG. 20) that occurs when the periodic flushing operation is overlapped with the cueing operation at least partially in the operation time is expressed by the following equation.
Δt3 = Tfl + Tcr2-Tpf3 (7)
When the values of Δt1 to Δt3 are negative values, the delay times Δt1 to Δt3 are set to zero (Δt = 0).

  The second determination unit 113 compares and determines the magnitudes of the delay times Δt1, Δt2, and Δt3 calculated by the calculation unit 114, determines the shortest one of these delay times, and corresponds to the one delay time. Select one action. At this time, if there are two or more delay times Δt1, Δt2, and Δt3 having the shortest value (including zero), the second determination unit 113 performs two or more operations corresponding to each delay time Δt. It is determined that one operation performed first is to be selected with priority. As priorities to be preferentially selected, in the case of the biting discharge method, the priorities are set in the order of initial biting operation, skew removal operation, and cueing operation. In the case of the reverse butt method, the priority is set in the order of the butt operation, the skew removing operation, and the cueing operation. The second determination unit 113 selects one operation by determination according to the determination rule. Then, the flushing control unit 94 requests the job control unit 95 to perform the flushing operation by designating a start timing for superimposing at least a part of the operation timing on one operation selected by the determination of the second determination unit 113. .

  The reason why the priority is set higher as the operation timing is earlier is that it is preferable to stop the thickening of ink that causes nozzle clogging early by performing periodic flushing early. is there. In other words, if the timing of regular flushing is delayed, the viscosity of the ink in the nozzles will increase by that delay, and the nozzle clogging will not be completely eliminated even after the flushing operation has been completed. This is because of the relative increase. Note that the skew removal method is not limited to the above two methods, and other methods may be used. For example, in the reverse rotation abutting method, the conveyance roller pair 18 is stopped, and the sheet 14 is placed on the conveyance roller pair 18 in the stopped state. A simple butting method of abutting the tip may be used. Further, depending on the printing conditions, there may be a feeding operation that does not perform the skew removal operation.

Next, the operation of the printer 11 will be described.
The flushing control performed in the printer 11 when the computer 73 executes the control program shown in the flowcharts of FIGS. 21 to 23 will be described. When the computer 73 receives the print job data D1 and accepts a print execution command based on the command therein, the computer 73 starts printing by the printer 11. The computer 73 acquires necessary information such as the print mode and the paper size based on the print condition data in the print job data D1.

  Hereinafter, the flushing control will be described with reference to FIGS. If the skew removal method determined in accordance with the mode at that time is a dripping method in which the paper 14 is merely carried to the cueing position without skew removal, the carriage 25 is not executed without executing the routine. Perform regular flushing immediately after stopping at the FL position. Then, in the case of the biting discharge method or the reverse hitting method, the computer 73 executes the routine. The regular flushing operation time Tfl is also simply referred to as flushing time Tfl.

First, in step S11, an FL movement time Tcr1 required for the carriage to move from the printing end position Xend to the flushing position Xfl is calculated. The FL movement time Tcr1 is calculated by the following equation.
Tcr1 = (Xend−Xfl−Sd1) / Vcr + Td1
Here, Xend is the printing end position of the last pass of the previous page, Xfl is the flushing position, Sd1 is the number of carriage deceleration steps, Vcr is the carriage constant speed, and Td1 is the carriage deceleration time when moving to the flushing position. The position uses an encoder conversion value (step count value), and the speed uses a motor rotation speed conversion value.

In step S12, a flushing time Tfl is calculated. The flushing time Tfl is calculated by the following equation.
Tfl = f (Δtfl)
Here, Δtfl is the flushing interval time counted by the FL timer 111. The function f (x) is a function that increases as the value of the variable x increases. The flushing interval time Δtfl is a value obtained by adding the value Δtflo acquired from the FL timer 111 at the end of printing (ink ejection end) and the time Tcr1 required for the carriage 25 to move from the print end position to the FL position. , Calculated from the equation Δtfl = Δtflo + Tcr1.

In step S13, a CR movement time Tcr2 required for movement from the flushing position Xfl of the carriage to the printing start position Xstr of the next page is calculated. The CR movement time Tcr2 is calculated by the following equation.
Tcr2 = Ta1 + (Xstr-Xfl-Sa2) / Vcr
Here, Ta1 is the carriage acceleration time when moving to the printing start position of the first pass of the next page, Xstr is the printing start position of the first pass of the next page, Xfl is the flushing position, and Sa2 is one pass of the next page. The acceleration step number of the carriage when moving to the print start position of the eye, Vcr is a constant carriage speed when moving to the print start position of the first pass of the next page.

  In step S14, the skew removal method is determined. That is, it is determined whether it is a biting and discharging method or a reverse butting method. If it is the biting discharge method, the process proceeds to step S15, and if it is the reverse-butting method, the process proceeds to step S18.

In step S15, an initial biting operation time Tpf1 is calculated. The initial biting operation time Tpf1 is calculated by the following equation.
Tpf1 = Tapf1 + Tdpf1 + (Spf1- (Sa1 + Sd1)) / Vpf
Here, Tapf1 is the paper acceleration time during the initial biting operation, Tdpf1 is the paper deceleration time during the initial biting operation, Spf1 is the number of initial biting driving steps, Sa1 is the number of acceleration steps during the initial biting operation, Sd1 is the number of deceleration steps during the initial biting operation, and Vpf is the constant speed of the paper during the initial biting operation.

In step S16, a skew removal operation time Tpf2 is calculated. The skew removal operation time Tpf2 is calculated by the following equation.
Tpf2 = Tapf2 + Tdpf2 + (Spf2- (Sa2 + Sd2)) / Vpf
Here, Tapf2 is the sheet acceleration time during the skew removal operation, Tdpf2 is the sheet deceleration time during the skew removal operation, Spf2 is the number of skew removal drive steps, Sa2 is the number of acceleration steps during the skew removal operation, and Sd2 is the skew removal. The number of deceleration steps during operation, Vpf, is the constant speed of the paper during the skew removal operation.

In step S17, a cueing operation time Tpf3 is calculated. The cueing operation time Tpf3 is calculated by the following equation.
Tpf3 = Tapf3 + Tdpf3 + (Spf3- (Sa3 + Sd3)) / Vpf
Here, Tapf3 is the paper acceleration time during the cueing operation, Tdpf3 is the paper deceleration time during the cueing operation, Spf3 is the number of cueing operation steps, Sa3 is the number of acceleration steps during the cueing operation, and Sd3 is the cueing operation. The number of deceleration steps during operation, Vpf, is the constant speed of the paper.

In step S18, the abutting operation time Tsf1 is calculated. The abutting operation time Tsf1 is calculated by the following equation.
Tsf1 = Tapf1 + Tdpf1 + (Spf1- (Sa1 + Sd1)) / Vpf
Here, Tapf1 is the sheet acceleration time during the abutting operation, Tdpf1 is the sheet deceleration time during the abutting operation, Spf1 is the number of abutting drive steps, Sa1 is the number of acceleration steps during the abutting operation, and Sd1 is the abutting The number of deceleration steps during operation, Vpf, is the constant speed of the sheet during the abutting operation.

  In step S19, a skew removal operation time Tpf2 is calculated. In this case, the reverse drive time of the transport roller pair performed by driving the transport motor 62 in reverse is calculated. The reverse drive amount Rr (rotation amount) and the reverse speed Vr are determined according to the mode, and the skew removal operation time Tpf2 is calculated by using the reverse drive amount Rr and the reverse speed Vr according to the mode at the time, the formula Tpf2 = Vr / Calculated by Rr.

In step S20, a cueing operation time Tpf3 is calculated. The cueing operation time Tpf3 is calculated by the following equation.
Tpf3 = Tapf3 + Tdpf3 + (Spf3- (Sa3 + Sd3)) / Vpf
Here, Tapf3 is the paper acceleration time during the cueing operation, Tdpf3 is the paper deceleration time during the cueing operation, Spf3 is the number of cueing drive steps, Sa3 is the number of acceleration steps during the cueing operation, and Sd3 is the cueing operation. The number of deceleration steps during operation, Vpf, is the constant speed of the paper during cueing operation.

  When the operation times Tpf1, Tpf2, and Tpf3 corresponding to the skew removal method are determined in this way, the feeding operation is performed using these operation times Tpf1, Tpf2, and Tpf3 in the processes after step S21 shown in FIGS. Among the plurality of operations constituting the period, one operation for superimposing at least a part of the periodical flushing and the operation time is determined. Then, a periodic flushing operation is performed by superimposing at least a part of the operation time on the determined one operation. Hereinafter, such processing after step S21 will be described with reference to FIGS.

  First, in step S21 in FIG. 22, it is determined whether or not the carriage can move to the flushing (FL position) within the initial biting operation time Tpf1. That is, the initial meal started when the FL movement time Tcr1 required for the carriage to move from the printing end position Xend of the last pass of the previous page to the flushing position Xfl reaches the printing end position of the last pass of the previous page. It is determined whether or not the attached operation time Tpf1 is shorter (Tcr1 <Tpf1). If Tcr1 <Tpf1 is satisfied, the process proceeds to step S22. If Tcr1 <Tpf1 is not satisfied, the process proceeds to step S30 shown in FIG.

  In step S22, it is determined whether or not the regular flushing can be completed within the initial biting operation time Tpf1. That is, it is determined whether the sum of the FL movement time Tcr1 and the flushing time Tfl is equal to or shorter than the initial biting operation time Tpf1 (Tcr1 + Tfl ≦ Tpf1 is satisfied). If Tcr1 + Tfl ≦ Tpf1 is satisfied, the process proceeds to step S27. If Tcr1 + Tfl ≦ Tpf1 is not satisfied, the process proceeds to step S23.

  In step S27, regular flushing is performed immediately after the carriage stops at the FL position. As a result, the regular flushing operation is performed by overlapping at least part of the operation timing with the alignment operation (initial biting operation or butting operation) started when the carriage 25 reaches the printing end position of the last pass of the previous page. Is done. In this case, in FIGS. 14 and 18, Tcr1 + Tfl ≦ Tpf1 is satisfied, and the periodic flushing operation is completed within the operation period of the biting operation or the butting operation, so that the feeding operation is not delayed. Note that the flushing operation may be started during deceleration immediately before the carriage 25 is stopped as long as the droplets discharged by the flushing operation are received by the droplet receiving portion (cap 55 in this example).

  In step S23, it is determined whether or not the flushing time Tfl falls within the skew removal operation time Tpf2 (whether Tfl ≦ Tpf2 is satisfied). If Tfl ≦ Tpf2 is satisfied, the process proceeds to step S28, and if Tfl ≦ Tpf2 is not satisfied, the process proceeds to step S24.

  In step S28, periodic flushing is performed in superposition with the skew removal operation. As a result, the periodic flushing operation is performed by superimposing at least a part of the operation timing on the skew removal operation. In this case, in FIG. 15 and FIG. 19, since the regular flushing is shorter than the operation period of the skew removal operation (Tfl ≦ Tpf2), the regular flushing operation ends within the operation period of the skew removal operation. Does not occur.

  In step S24, the respective delay times Δt1, Δt2, and Δt3 when the periodic flushing is superimposed on each of the feeding operations are calculated. That is, when the operation timing of the regular flushing operation is at least partially overlapped with one of a plurality of operations in the feeding operation, the delay times Δt1, Δt2, and Δt3 are set for each operation to be overlapped. calculate. Specifically, the delay time Δt1 when the periodic flushing operation is at least partially overlapped with the operation period of the initial biting operation is calculated by the equation Δt1 = Tcr1 + Tfl−Tpf1 (see FIG. 14). Further, the delay time Δt1 when the periodic flushing operation is at least partially overlapped with the operation period of the butting operation is calculated by the equation Δt1 = Tcr1 + Tfl + Tpf2−Tpf1 (see FIG. 18). Further, the delay time Δt2 when the periodic flushing operation is at least partially overlapped with the operation period of the skew removal operation is calculated by the equation Δt2 = Tfl−Tpf2 (see FIGS. 15 and 19). Further, the delay time Δt3 when the periodic flushing operation is at least partially overlapped with the operation period of the cueing operation is calculated by the equation Δt3 = Tcr2 + Tfl−Tpf3 (see FIGS. 16 and 20).

  In step S25, it is determined whether or not Δt1 is the shortest. That is, it is determined whether or not Δt1 ≦ Δt2 and Δt1 ≦ Δt3 are satisfied. When the delay time Δt1 is the shortest, the process proceeds to step S27, and when the delay time Δt1 is not the shortest (that is, Δt1> Δt2 and Δt1> Δt3 are satisfied), the process proceeds to step S26.

  In step S27, regular flushing is performed immediately after the carriage stops at the FL position. As a result, the regular flushing operation is performed by overlapping at least part of the operation timing with the alignment operation (the biting operation or the abutting operation) started when the carriage 25 reaches the printing end position of the final pass of the previous page. The In this case, in FIGS. 14 and 18, Tcr1 + Tfl> Tpf1 is satisfied, and the periodic flushing operation cannot be completed within the operation period of the initial biting operation or the butting operation, and at the start time of one operation in the feeding operation A delay of delay time Δt1 occurs.

  In step S26, it is determined whether or not Δt2 is the shortest. That is, it is determined whether or not Δt2 ≦ Δt3 is satisfied. If Δt2 ≦ Δt3 is satisfied, the process proceeds to step S28. If Δt2 ≦ Δt3 is not satisfied, the process proceeds to step S29.

  In step S28, periodic flushing is performed in superposition with the skew removal operation. In this case, in FIG. 15 and FIG. 19, since the operation period of the regular flushing operation is longer than the operation period of the skew removal operation (Tfl> Tpf2), the regular flushing operation cannot be completed within the operation period of the skew removal operation. A delay of Δt2 occurs at the start time of one of the sending operations (ie, cueing operation).

  In step S29, periodic flushing is performed in superposition with the cueing operation. In this case, in the example of FIGS. 16 and 20, the carriage 25 that has completed the periodic flushing operation after the cueing operation is completed after Tcr2 + Tfl> Tpf3 is reached, reaches the print start position of the first pass of the next page, and is printed. Is delayed by a delay time Δt3.

  In step S30, it is determined whether or not the carriage can move to the FL position within the skew removal operation time Tpf2 (whether Tcr1 <Tpf1 + Tpf2 is satisfied). That is, it is determined whether or not the regular flushing can be superimposed on the skew removing operation from the middle thereof. If Tcr1 <Tpf1 + Tpf2 is satisfied, the process proceeds to step S31. If Tcr1 <Tpf1 + Tpf2 is not satisfied, the process proceeds to step S32.

  In step S31, it is determined whether the regular flushing can be completed within the skew removal operation time Tpf2 (whether Tcr1 + Tfl ≦ Tpf1 + Tpf2 is satisfied). That is, it is determined whether or not the regular flushing operation is within the skew removal operation time Tpf2 even if it is started in the middle of the skew removal operation. If Tcr1 + Tfl ≦ Tpf1 + Tpf2 is satisfied, the process proceeds to step S35. If Tcr1 + Tfl ≦ Tpf1 + Tpf2 is not satisfied, the process proceeds to step S32.

  In step S35, periodic flushing is performed in superposition with the skew removal operation. In this case, the carriage 25 stops at the FL position in the middle of the start of the skewing operation after the end of the initial biting operation or the butting operation, and the periodic flushing operation is performed by superimposing the operation timing on the skew removal operation from the middle. To be implemented. Unlike the example of FIG. 17, the regular flushing operation ends before the end of the skew removal operation, and the delay time Δt2 does not occur.

  In step S32, it is determined whether or not the sum of the flushing time Tfl and the movement time Tcr2 to the print start position of the next page falls within the cueing operation time Tpf3 (Tfl + Tcr2 ≦ Tpf3 is satisfied). In other words, when periodic flushing is added to the cue operation and the operation time is overlapped from the start of the operation, printing (ink ejection) from the print start position of the first pass of the next page can be performed simultaneously with the end of the cue operation, It is determined whether or not a delay occurs at the print start time of the first pass of the next page. If Tfl + Tcr2 ≦ Tpf3 is satisfied, the process proceeds to step S36. If Tfl + Tcr2 ≦ Tpf3 is not satisfied, the process proceeds to step S33.

  In step S36, periodic flushing is performed in superposition with the cueing operation. In this case, the driving of the carriage 25 can be started at a timing at which printing can be started at the end of the cueing operation after the end of the regular flushing operation. For this reason, there is no delay in the print start time in the first pass of the next page.

  In step S33, the respective delay times Δt2 and Δt3 when the periodic flushing is superimposed on each of the skew removal operation and the cueing operation are calculated. That is, when at least a part of the periodical flushing operation timing is superimposed on one of the skew removal operation and the cueing operation, the delay times Δt2 and Δt3 are calculated for each operation to be superimposed. Specifically, the delay time Δt2 when the periodic flushing operation is at least partially overlapped with the operation period of the skew removal operation is calculated by the equation Δt2 = Tcr1 + Tfl− (Tpf1 + Tpf2) (see FIG. 17). Further, the delay time Δt3 when the periodic flushing operation is at least partially overlapped with the operation period of the cueing operation is calculated by the equation Δt3 = Tcr2 + Tfl−Tpf3 (see FIGS. 16 and 20).

  In step S34, it is determined whether or not Δt2 is the shortest among Δt2 and Δt3 (whether Δt2 ≦ Δt3 is satisfied). If Δt2 ≦ Δt3 is satisfied, the process proceeds to step S35, and if Δt2 ≦ Δt3 is not satisfied, the process proceeds to step S36.

  In step S35, periodic flushing is performed in superposition with the skew removal operation. In this case, the carriage 25 stops at the FL position FP in the middle of the skew removal operation, and the regular flushing operation is carried out by superimposing at least a part of the operation timing on the skew removal operation from the middle, and after the skew removal is finished, The flushing operation ends. For this reason, a delay of Δt2 occurs at the start timing of the cueing operation (see FIG. 17).

  On the other hand, in step S36, periodic flushing is performed in superposition with the cueing operation. In this case, after the end of the regular flushing operation, the carriage 25 starts to move from the FL position FP toward the print start position of the first pass of the next page, and after the cueing operation is finished, the carriage 25 starts the first page of the next page. A delay of Δt3 occurs until the printing start position of the pass is reached and printing is started (see FIGS. 16 and 20).

  As described above, when the delay time Δt does not occur or the value of the delay time Δt is the same, priority is given to one operation performed earlier among a plurality of operations in the feeding operation, and the periodic flushing operation is performed. At least partially overlap the time. When a delay time occurs, at least a part of the operation timing of the regular flushing operation is superimposed on one operation that requires the shortest delay time.

  Therefore, the periodic flushing operation is performed in the feeding operation even in a configuration in which each operation time of the plurality of operations constituting the feeding operation and the periodic flushing is changed according to the printing mode and the printing pattern at that time. It is possible to superimpose at least a part of the operation time on one optimal operation. Then, it is possible to suppress a delay in the feeding operation for feeding the next page of paper to the print start position and a delay in the printing start time for starting printing on the next page of paper.

According to the embodiment described in detail above, the following effects can be obtained.
(1) A flushing operation in which the print head 26 is stopped to face the cap 55 to eject ink droplets is performed within a page switching period from when the print head 26 stops at the flushing position FP until the movement is resumed. To do. During the page switching period, when the flushing operation is performed by superimposing at least a part of the operation timing on one of the plurality of operations constituting the feeding operation, the operation is started after the end of the regular flushing operation. One operation with the least delay in the start time of the next operation is predicted. Then, the periodic flushing operation is performed by superimposing at least a part of the operation time on the predicted one operation. Therefore, the delay of the feeding operation can be reduced as compared with the configuration in which the flushing operation is performed by superimposing at least a part of the operation timing on one of the plurality of operations constituting the feeding operation. Can do. For this reason, since the printing of the next page can be started early, the printing throughput of the printer 11 can be improved.

  (2) When a periodic flushing operation is performed by superimposing at least a part of the operation timing on one operation among a plurality of operations constituting the feeding operation, both the one operation and the flushing operation are terminated. A delay time of the start timing of the next operation that is started after waiting is predicted for each of the plurality of operations. Then, the flushing operation is performed by superimposing at least a part of the operation timing on one operation satisfying the condition that the predicted delay time is the shortest. Therefore, printing by the print head 26 on the paper 14 fed by the feeding operation can be started at an early stage.

  (3) When there are two or more operations that satisfy the condition that the delay time Δt is minimized, one operation is determined according to the set priority order among the two or more operations. Therefore, one more appropriate operation according to the priority order can be determined as an overlap target of the flushing operation.

  (4) As an aligning operation, a biting operation in which the paper 14 is sandwiched (nip) between the conveyance roller pair 18 so that the leading end of the paper 14 protrudes downstream in the conveyance direction of the conveyance roller pair 18; A biting discharge method including a discharge operation in which the tip ends of 14 are bent from the conveyance roller pair 18 toward the upstream side in the conveyance direction is adopted. Therefore, the delay of the start time of the next operation started after the end of the regular flushing operation can be shortened as much as possible.

  (5) As an alignment operation, an abutting operation in which the leading end of the sheet 14 on the downstream side in the conveying direction is abutted against the conveying roller pair 18; A reverse rotation abutting method including a reverse rotation operation of rotating the conveyance roller pair 18 in the rotation direction that can be conveyed to the side is adopted. Therefore, the delay of the start time of the next operation started after the end of the regular flushing operation can be shortened as much as possible.

  (6) Among the plurality of operations constituting the feeding operation, the periodic flushing operation is stopped when starting one operation in which at least a part of the periodic flushing operation and the operation time is overlapped. Therefore, even when the main control unit 91 can instruct the sequence control unit 92 to execute the operation only when the flushing operation is stopped, the regular flushing operation can be started after starting one operation. For this reason, the flushing operation can be performed by superimposing at least a part of the operation time on one operation.

  (7) With respect to the operation (initial biting operation or abutting operation) that has already been started when the print head 26 that has finished printing on the paper 14 has moved to the flushing position FP facing the cap 55 and stopped. Then, the regular flushing operation is started from the stop point. On the other hand, for an operation that has not yet started when the print head 26 is stopped, the stop flushing operation is started after the start of the operation. Therefore, it is possible to ensure a long period in which the operation timing of the regular flushing operation and one operation can be overlapped.

  (8) The scanning operation in which the print head 26 moves for printing the first pass of the next page after the end of the regular flushing operation is started before the end of the cueing operation. For this reason, since the operation timings of the scanning operation and the cueing operation of the print head 26 are at least partially overlapped, printing by the print head 26 on the paper 14 conveyed by the cueing operation can be started at an early stage. . For example, it can contribute to an improvement in printing throughput.

  (9) Since at least the operation time of the periodic flushing operation is variable among the operation times (required times) of the plurality of operations constituting the periodic flushing operation and the feeding operation, the operation of the flushing operation for each page (paper 14) Even if the time changes, it is possible to perform the flushing operation for each page by superimposing at least a part of the operation time on one appropriate operation. In particular, in the present embodiment, since all of the operation times (required times) of a plurality of operations constituting the flushing operation and the feeding operation are variable, even if the operation time of each operation varies from page to page, it is different for each page. In addition, the flushing operation can be performed by superimposing at least a part of the operation time on one appropriate operation.

In addition, the said embodiment can also be changed into the following forms.
An allowable range (allowable value) may be set when comparing the magnitudes of the delay times Δt1, Δt2, and Δt3. The control unit (computer 73), for example, compares and determines the delay times Δt1, Δt2, and Δt3 under the allowable value Δα (where Δα> 0), and the delay time is the shortest under the allowable value. A configuration is adopted in which one operation that satisfies the shortening condition is selected. For example, if Δt1> Δt2 + Δα and Δt2> Δt3 + Δα are satisfied, one operation corresponding to the delay time Δt3 is selected, and if both of the two conditions are not satisfied, an operation corresponding to the delay time Δt1 is selected. If the former condition is satisfied and the latter condition is not satisfied, an operation corresponding to the delay time Δt2 is selected. In addition, when there are two or more operations that satisfy the above conditions, it is preferable to select one appropriate operation according to the set priority order.

  -It is not limited to the structure which selects one operation | movement corresponding to the shortest delay time among several delay time (DELTA) t1-Δt3 as a superimposition object of flushing operation | movement. For example, each operation time (required time) Tpf1, Tpf2, and Tpf3 of a plurality of operations constituting the feeding operation is obtained, and these operations are compared in size to superimpose one operation satisfying the longest operation time on the flushing operation. The structure selected as object may be sufficient. Also with this configuration, it is possible to select one operation that can minimize the delay of the start time of the operation that is started next to the flushing operation as an overlap target of the flushing operation. In addition, when there are two or more operations that satisfy the above conditions, it is preferable to select one appropriate operation according to the set priority order.

-One kind of alignment operation may be employed in the printing apparatus. For example, only the reverse abutment method may be employed, or only the biting discharge method may be employed.
In the above embodiment, all the operation times of the regular flushing operation and the plurality of operations in the feeding operation are variable, but at least one of these operations may be variable. For example, it is sufficient that at least the operation time of the regular flushing operation is variable. With this configuration, the periodical flushing operation time can be as short as possible according to the elapsed time from the end of the previous flushing operation, and the frequency of occurrence of delays in the feeding operation can be reduced. Of course, a configuration in which the operation time of the regular flushing operation is constant and at least one of the feeding operations is variable is also possible.

  -ASF / CR overlay control may be abolished. That is, after the carriage 25 that has finished printing by the print head 26 at the printing end position of the last pass of the previous page stops at the flushing position FP, the feeding operation is started, and at least the end of the feeding operation is waited before the next page. The scanning operation of the carriage 25 for the first pass may be started.

  The priority order is not limited to a setting that gives priority to an operation that is performed earlier, but may be a setting that gives priority to an operation that is executed later, for example. Further, the priority order may be set in an order that is not related to the order of the implementation times.

  In the above embodiment, the alignment operation includes two operations (initial biting operation and skew removal operation, butting operation and skew removal operation), but the alignment operation may include at least one operation. For example, even in a configuration in which the alignment operation consists of one operation, one operation to be superposed on the flushing operation can be selected from the two operations of the alignment operation and the cue operation.

  The feeding operation may include operations other than the skew removal operation (an example of the alignment operation) and the cue operation. For example, the sheet feeding confirmation operation described in Patent Document 1 may be included. Further, when the second sensor 64 detects the leading edge of the paper 14, the feeding of the paper 14 is temporarily stopped, and the initial biting operation and the abutting operation are performed before the stop (initial feeding operation), It may be divided into an operation after the stop (initial biting operation or butting operation).

  A through hole for flushing is provided as an example of a droplet receiving portion on the upper surface of the end position outside the scanning area during printing (left end position in FIGS. 2 and 3) on the support base 29 opposite to the home position HP. An opening or a flushing box may be arranged. A configuration in which the droplet receiving portions are provided on both sides of the scanning area of the print head 26 during printing may be employed. With this configuration, regardless of whether the carriage scanning direction that moves the final path of the final page is forward or backward, the print head 26 moves to a position facing the droplet receiving portion ahead of the current traveling direction, and flushing is performed. It can be performed.

  -You may replace a feeding motor and a conveyance motor with one motor which shared the power source of a feeding system and a conveyance system. For example, a power transmission switching unit (clutch mechanism) is provided between the feed system and the conveyance system and the motor, and the power transmission destination can be selected for at least one of the feeding system and the conveyance system by switching the power transmission switching unit. do it. In this case, if the configuration is such that the direction of turning of the power transmitted by the switching position of the power transmission switching unit can be selected, it is also possible to perform the skew removal operation of the biting discharge method and the reverse contact method.

  Each functional part constituting each functional part in the computer 73 is realized only by software by a CPU that executes a program, realized only by hardware by an electronic circuit such as an ASIC, or cooperation between software and hardware. It may be realized by work.

The feeding device may be a system that feeds roll paper as an example of a print medium.
The printing apparatus is not limited to a serial printer as long as it is an inkjet type, and may be a line printer. Even in line printers, when the flushing time is reached, a flushing operation is performed by moving the line-type print head from the position in the print medium transport area during printing to a position facing the droplet receiving portion outside the transport area. If it is. The printing apparatus is not limited to a printer having only a printing function, and may be a multifunction machine.

  The printing medium is not limited to paper, and may be a resin film or sheet, a metal foil, a metal film, a resin-metal composite film (laminate film), a woven fabric, a nonwoven fabric, a ceramic sheet, or the like.

  DESCRIPTION OF SYMBOLS 11 ... Printer as an example of a printing apparatus, 14 ... Paper as an example of a printing medium, 17A, 36 ... Intermediate roller which comprises an example of a conveyance part, 18 ... The conveyance roller pair which comprises an example of a conveyance part, 19, 20 DESCRIPTION OF SYMBOLS ... Discharge roller pair, 25 ... Carriage, 26 ... Print head, 30 ... Linear encoder, 53 ... Carriage motor, 55 ... Cap as an example of droplet receiving part, 62 ... Conveyance motor, 61, 68 ... Encoder, 63 ... No. 1 sensor, 64 ... second sensor, 67 ... feed motor, 70 ... controller constituting an example of control unit, 73 ... computer constituting an example of control unit, 85 ... nonvolatile memory, 85a ... flushing information storage unit, 91 ... Main control unit, 92 ... Sequence control unit, 93 ... Print control unit, 94 ... Flushing control unit, 5 ... Job control unit, 97 ... CR control unit, 97A ... CR counter, 98 ... PF control unit, 98A ... PF counter, 99 ... ASF control unit, 99A ... ASF counter, 111 ... FL timer, 113 ... Second determination unit , 114... Arithmetic unit, Tf... Flushing interval time, .DELTA.t1, .DELTA.t2, .DELTA.t3... Delay time, Tpf1, Tpf2, Tpf3.

Claims (11)

A print head that performs printing by moving relative to the print medium and ejecting droplets onto the print medium;
A transport roller pair disposed upstream of the print head in the transport direction of the print medium and transporting the print medium to the print head; and at least one operation of aligning the print medium with respect to the transport roller pair A conveying unit that performs a feeding operation including a plurality of operations including an aligning operation and a cueing operation that conveys the print medium to a printing start position by the conveying roller pair;
A control unit for controlling the print head and the transport unit;
A liquid droplet receiving part that receives the liquid droplets disposed outside the scanning region during printing of the print head;
Have
When the control unit performs a flushing operation for stopping the print head against the droplet receiving unit and discharging the droplets, a period from when the print head is stopped to when movement is resumed A delay in the start timing of the next operation that is started after the end of the flushing operation when the flushing operation is performed by superimposing at least a part of the operation timing on one of the plurality of operations. A printing apparatus that predicts one operation that requires the least amount and performs the flushing operation by superimposing at least a part of the operation time on the predicted one operation.   When the controller performs the flushing operation by superimposing at least a part of the operation timing on one of the plurality of operations, the control unit waits for completion of both the one operation and the flushing operation. A delay time of a start time of a next operation to be started is predicted for each of the plurality of operations, and an operation satisfying a condition that minimizes the delay time is predicted as the one operation. The printing apparatus according to 1.   When the controller performs the flushing operation by superimposing at least a part of the operation timing on one of the plurality of operations, the control unit waits for completion of both the one operation and the flushing operation. The delay time of the start time of the next operation to be started is predicted for each of the plurality of operations, and the operation that satisfies the shortest condition with the delay time being given an allowable range is predicted as the one operation. The printing apparatus according to claim 1.   The control unit predicts a required time of each of the plurality of operations, and performs the flushing operation by superimposing at least a part of the operation time on one operation satisfying the condition that the predicted required time is the longest. The printing apparatus according to claim 1.   5. The control unit according to claim 2, wherein when there are two or more operations that satisfy the condition, the control unit determines one operation according to a set priority order among the two or more operations. A printing apparatus according to claim 1. The alignment operation is a biting operation that bites the transport roller pair in a state in which a front end portion of the print medium protrudes downstream in the transport direction of the transport roller pair;
6. The printing apparatus according to claim 1, further comprising: a discharging operation of discharging the bitten tip portion upstream in the transport direction. The alignment operation includes an abutting operation that abuts the leading end of the printing medium in the conveyance direction on the conveying roller pair, and the printing medium when the leading edge of the printing medium abuts on the conveying roller pair by the abutting operation. 6. The printing apparatus according to claim 1, further comprising a reverse operation that reversely rotates the transport roller pair in a rotation direction in which the medium can be transported upstream in the transport direction.   8. The flushing operation is stopped when the one operation in which at least a part of the flushing operation and the operation timing are overlapped is stopped. 9. Printing device.   For the operation that has already started at the stop point when the print head that has finished printing on the print medium has finished moving to the position facing the droplet receiving part, the control unit starts from the stop point. 9. The flushing operation is started, and for an operation that has not yet started at the stop time, the flushing operation is started after waiting for the start of the operation. The printing apparatus as described in.   10. The printing apparatus according to claim 1, wherein the scanning operation of the print head after the flushing operation is started before the end of the cueing operation.   The printing according to any one of claims 1 to 10, wherein at least the time required for the flushing operation is variable among the time required for a plurality of operations constituting the flushing operation and the feeding operation. apparatus.